, AUTOMOBILE CONSTRUCTION, OPERATI A'.NTZN/ KCE f " REPA' LIBRARY OF \ HERBERT S. CONANT \ S TROY, N. Y. ; 5 i ,***+**> . ... ...** ! V* Spar A /% End Sectional View of Typical Internal Combustion Motor. The Prime Mover that Made the Automobile, Motorcycle, Aeroplane, and Motor Boat Possible, THE MODERN GASOLINE AUTOMOBILE ITS DESIGN, CONSTRUCTION MAINTENANCE AND REPAIR A PRACTICAL, COMPREHENSIVE TREATISE EXPLAIN- ING ALL PRINCIPLES PERTAINING TO GASOLINE AUTOMOBILES AND THEIR COMPONENT PARTS. THE MOST COMPLETE UP-TO-DATE TREATISE ON GASOLINE AUTOMOBILES EVER PUBLISHED INVALUABLE TO MOTORISTS, STUDENTS, MECHANICS, REPAIR MEN AUTOMOBILE DRAUGHTSMEN, DESIGNERS AND ENGINEERS. EVERY PHASE OF THE SUBJECT BEING TREATED IN A PRACTICAL, NON-TECHNICAL MANNER VICTOR W. PAGE, M.E. LATE TECHNICAL EDITOR OF "THE AUTOMOBILE JOURNAL*' AUTHOR "THE MODERN GAS TRACTOR," "AUTOMOBILE QUESTIONS AND ANSWERS," ETC. NEW, REVISED AND ENLARGED EDITION SHOWING ALL RECENT IMPROVEMENTS Illustrated By 575 Special// Made Detailed //lustrations and Diagrams THE ILLUSTRATIONS DEFINING CONSTRUCTION OF PARTS ARE MADE FROM ACCURATE ENGINEERING DRAWINGS ACCORDING TO BEST AUTOMOBILE ENGINEERING PRACTICE NEW YORK THE NORMAN W. HENLEY PUBLISHING COMPANY 132 NASSAU STREET 1914 COPYRIGHTED, 1914, 1913 AND 1912, BY THE NOKMAN W. HENLEY PUBLISHING COMPANY COPYRIGHTED IN ENGLAND AND ALL OTHER COUNTRIES WHICH HAVE BECOME PARTIES TO THE BERNE CONVENTION All rights reserved THIRD ni!'l;i:ssu>N i; I 'VISED AND ENLARGED All illustrations in this book have been specially made by the publishers, and their use without permission is strictly prohibited COMPOSITION, ELKCTROTYPING AND PRESSWORK THE TROW PRESS, NEW YORK, U. S. A. 205 P I M PREFACE TO 1914 EDITION jci While the major portion of the 1913 edition of this work remains unchanged owing to the highly developed state of the art at the time it was first prepared, it has been found desirable to prepare much addi- tional matter for this latest edition in order to keep pace with the progress of the industry. The entire work has been thoroughly revised and a number of corrections made in the text. Much supplementary matter has been added relating to ignition, the action of magneto generators and basic principles on which they operate, so this subject should be more easy of comprehension. Entirely new material has been added on tractors in three- and four-wheel forms, cyclecars and agricultural tractors or automobile plows ; combination gasoline-electric drive, front-wheel and four-wheel drive and steer systems and other important developments in power propelled vehicles. The discussion of power transmission methods has been augmented by consideration of the skew bevel gear and two-speed direct drive rear axle, as well as sev- eral new forms of worm gear drive. The subject of electrical motor starting systems has been considered at length and all leading systems and their components described. A discussion on ball and roller bear- ings, their maintenance and installation, has also been included, and a number of other features of timely interest such as latest types of gasoline and kerosene carburetors, cyclecar power plants, the Fischer slide valve motor, detachable wire wheels, etc., have been added to bring the work thoroughly up to date. Many new illustrations have been made to illustrate the new matter and the treatment of some of the subjects changed a trifle upon the advice of various educators to permit the work to be used to somewhat better advantage in teaching classes in automobile engineering courses in various technical schools that have adopted this work exclusively as a text-book. THE" AUTHOR. April 1, 1914. TO MY UNCLE ERNEST F. MCCARTHY A PIONEER AUTOMOBILE DESIGNER AND CONSTRUCTOR THIS TREATISE IS INSCRIBED IN GRATEFUL APPRECIATION OF PRACTICAL AID AND MECHANICAL INSTRUCTION GIVEN AT A TIME IT WAS MOST NEEDED CONTENTS CHAPTER I PAGES Defining Trend of Modern Practice Explaining Components of Motor Cars and Considering Functions of Each Group of Mechanism Parts of Typical Pleasure Car Chassis Assembling Typical Chassis Arrangement of Truck Parts Wind Resistance and Body De- signClassification of Motor-Car Types Utility of Three-Wheel Tractor Advantages in Three-Wheel Construction Two-W 7 heel and Four-Wheel Drive Trucks Light Cars and Cycle Cars Agri- cultural Automobiles or Gas Tractors Automobile Plow . . 45-99 CHAPTER II How Power is Generated Forms of Power Plants Commonly Used Two- and Four-Cycle Engine Action How the Gasoline Engine Works Internal Combustion Motor Parts and Their Functions Typical Single-Cylinder Engines Described Sequence of Cycles in One- and Two-Cylinder Engines Sequence of Cycles with Multiple- Cylinder Engines Actual Duration of Strokes Typical Engine Types Described Features of Knight Slide- Valve Motor Action of Poppet Valve Motor Described Operating Principles of Two-Cycle Engines Two-Port Two-Cycle Motor Action How Three-Port Two- Cycle Engine Operates Action of Differential Piston Two-Cycle Motor Why Two-Cycle Motor is Not Widely Used in Automobiles Power-Plant Installation Three-Point Support Unit Power- Plant Advantages 100-142 CHAPTER III The Principal Parts of Gasoline Engines, Their Design, Construction, and Application Methods of Cylinder Construction Influence" of Crankshaft Design Combustion-Chamber Design Bore and Stroke Ratio Meaning of Piston Speed Advantages of Offset Cylinders Influence of Cylinder Construction on Engine Design Valve Lo- cation of Vital Import Separable Head Motors Valve Design and Construction Valve Operation Means Methods of Driving Cam- shaft Spur Camshaft Gearing Silent Chain Camshaft Drive 1 2 Contents PAOE8 Valve Springs Piston and Rotary Valve Motors The Valveless Miesse Engine The Itala Rotary Valve Motor The Reynolds Ro- tary Valve Design Cylindrical and Conical Rotary Valves The Sphinx Ring- Valve Motor Darracq Rotary Distributor Valve The Hewitt Piston-Valve Motor Valve Timing Causes of Blowing Back Lead Given Exhaust Valve Exhaust Closing, Inlet Open- ing Closing the Inlet Valve Time of Ignition Typical Valve- Timing Diagrams Outlined Unconventional Poppet Valve Arrange- ment The Fischer Slide Valve Motor 143-213 CHAPTER IV Constructional Details of Pistons Methods of Wristpin Retention Pis- ton-Ring Construction Connecting-Rod Forms Camshaft Forms Crankshaft Types Outlined Typical Built-up Crankshaft Two- Cylinder Crankshaft Types for Four- and Six-Cylinder Engines Bali-Bearing Crankshafts Flywheel Construction and Retention Utility of Fan-Blade Form Spokes Marking Flywheel Rim to Indicate Valve Timing Engine-Base Construction Outlined Barrel Type Crankcase Divided Crankcases Typical Two-Cycle Motors The Amplex Power Plant The Legros Design Features of Cot< Differential Piston Motor The Rayner Construction Conventional Four-Cycle Power Plants Cyclecar Power Plants . . . 214-263 CHAPTER V Defining Liquid Fuels Used and Methods of Vaporizing to Obtain Ex- plosive Gas Distillates of Crude Petroleum Benzol and Its Prop- erties Special Vaporizers Needed for Kerosene Advantages of Al- cohol Solid Gasoline as Fuel Principles of Carburetion Outlined What a Carburetor Should Do Methods of Carrying Fuels in Automobiles Gravity-Feed Systems Gasoline Supply by Pressure Fuel Supply by Pump Early Vaporizer Forms Wick Carbu- retor Construction Filtering or Bubbling Vaporizers Marine Type Mixing Valves Development of Float-Feed Carburetor Elements of Carburetor Design Mixing Chamber Forms Problem of Float-Bowl Design Gasoline Spray Xozzle Forms Important Typical Auxiliary Air Valves Methods of Gas-Supply Regulation Use of Automatic Governor Construction of Modern Carbu- retors Schebler Models Kingston Carburetor Holley Carburetor Features Features of Mercedes Carburetor Chapin Carburetor De- sign Excelsior Carburetor Construction Fierce-Arrow Vaporizer Grouvelle and Arquemburg Mixing Device Peerless Carburetor and Induction Manifold Breeze Automatic Carburetor Features Contents FAQE8 Multiple-Nozzle Carburetors Stromberg Double-Jet Device Car- buretor Used on F. I. A. T. Motor Saurer Economy Carburetor The Zenith Appliance Utility of Gasoline Strainers How Kero- sene May Be Utilized Holley Kerosene Vaporizer Supplying Kerosene by Direct Injection Intake Manifold Design and Con- struction Compensating for Varying Atmospheric Conditions Disposition of Exhaust Gases Muffler Forms Utility of Cut-Out Valve Kerosene Vaporizer Using Water Spray The 1914 Holley Kerosene Carburetor A Camphor Vaporizer The Ford Gasoline Carburetor Muir Automatic Carburetor The Diesel System . 264-352 CHAPTER VI Automobile Power-Plant Ignition Systems Outlined Chemical Current Production How Primary Cells are Used Construction of Dry Battery Methods of Coupling Dry Cells Principles of Storage- Battery Construction Dynamo Electric Machines Typical Gov- erned Dynamo Ford Magneto Generator Distinctive Tinier and Distributor Forms Arrangement of Timer Contacts Essential Ele- ments of Simple Ignition System Induction-Coil Forms Spark- Plug Design and Application Plugs for Two-Spark Ignition Typical Battery Ignition Systems Features of Low-Tension Igni- tion Make and Break Igniter Plate Magneto-Generator Construc- tion High-Tension Magneto Systems Inductor Magneto Design Installation and Drive of Magnetos Double-Ignition System . 353-413 CHAPTER VII Reason for Lubrication of Mechanism Theory of Lubrication Deriva- tion of Lubricants Devices for Supplying Oil Gravity Feed Oil- ers Mechanical Oiling Methods Oil Supply by Constant Level Splash System Distributing Lubricant by Pressure Individual Pump System Why Cooling Systems are Necessary Cooling Sys- tems Generally Applied Cooling by Positive Water Circulation Forms of Water Pumps Water Circulation by Natural System Direct Air-Cooling Methods Utility of Auxiliary Exhaust Valves Forms of Air Fans Two-Cycle Air-Cooled Engine The Frank- lin Air-Cooling System The Frayer-Miller Blower System . 414-451 CHAPTER VITI Utility of Clutches and Gearsets Defined Why These are Needed on All Gasoline-Motor-Driven Vehicles Clutch Forms and Their Require- ments How Friction Clutches Transmit Power Materials Em- Contents PAGI ployed to Increase Frictional Adhesion Forms of Cone Clutches Outlined Attaching Leather Facings to Cones Securing Gradual Engagement Three- and Five-Plate Clutches Features of Multi- ple-Disc Clutches Functions of Gearsets Face-Friction Gearing Installing Face-Friction Gears How Planetary Gearing Operates Typical Planetary Gearsets Form Using Internal Gears All Spur Epicyclic Gearing Individual Clutch Transmission Silent Chain Transmission How Sliding Gearsets Operate Action of Progres- sive System Operation of Selective Sliding Gearset Typical Three- and Four-Speed Sliding Gearsets Methods of Installing Change Speed Gearing in Chassis Combination with Power Plant Unit Rear Axle Transmission Gear Combination Transmission Gear for Four-Wheel Drive Combination Gasoline-Electric Drive The Couple-Gear Four-Wheel Drive System 452-519 CHAPTER IX The Chassis and Its Components Frame Design and Construction Ad- vantages of Low Weight Placing Underslung Frame Type Ma- terials Employed in Frame Construction Suspension of Motor Vehicles Design of Leaf Springs Suspending Front Ends of Motor- Car Frames Rear End Suspension Unconventional Spring Forms How Automobiles are Steered Features of Pivoted Axle Rack and Pinion Steering Gear Worm Gear Reduction Steering Device Thread and Nut Steering Arrangement Spark and Throttle Lever Location Front Axle Forms I Beam Axle Tubular Axle Construction Steering Knuckle Design Methods of Power Trans- mission Straight Line Shaft Drive Rear Axle Types Live and Stationary Axle Combination Purpose of Differential Gear Bevel Gear Drive Assembly Worm Gear Driving Axles Employing Dou- ble Reduction Gearing Chain Driving Method Utility of Motor- Car Brakes Forms of Brakes Internal and External Band Brakes Multiple-Disc Brake Application of Front Wheel Brakes Four- Wheel Drive System Skew Bevel Drive Gearing Two-Speed Direct Drive Axle Differential Locks Practical W T orm Gear Drive Sys- temsSingle Chain Drive 520-587 CHAPTER X Wheels, Rims and Tires Characteristics of Wooden Wheels Wire and Metal Wheels Spring and Resilient Wheels Forms of Automobile Tires Construction of Pneumatic Tires Clincher Type Dunlop Type Outer Casing Quick Detachable Rim Forms Fisk Bolted-On Contents 5 PAGES Casing Forms of Outer Casing Treads Supplementary Treads and Anti-Skidding Attachments Demountable Rim Forms Fea- tures of Cushion Tires Sectional Cushion Tires Forms of Solid Rubber. Tires Methods of Fastening Solid Tires Twin Type Solid Tires Tools and Supplies for Pneumatic Tire Restoration Tire Irons and Their Use Small Repair Kit for Emergency Repairs Tire Manipulation Hints Loosening Clincher Casings from Rim of Wheel Tools for Removing Bolted-On Casings Rules for Tire Selection and Inflation Increase in Air Pressure Caused by Driv- ing Tire Repair and Maintenance Some Conditions That Cause Tire Failure Repairing Punctures Restoring Outer Casing That Has " Blown Out " Small Vulcanizers and Their Use Replacing Inner Tubes Advantages of Detachable Wheels Ball and Roller Bearings 588-646 CHAPTER XI Motor Car Equipment and Accessories Self-Starters for Gasoline En- gines Ignition Starters Gas Starting Systems Compressed Air Starting Methods Starting the Gasoline Engine by Electric Motor Electric Starting Systems for 1914 One-Unit System Two- Unit Electric Starting System Motor Car Lighting Systems Acetylene Gas Lighting Systems Method of Generating Gas Ac- tion of Automatic Generator Electric Lighting Systems Special Lighting Battery Forms of Electric Lamps Combination Kero- sene and Electric Lamps Incandescent Bulbs and Sockets Special Electric Lighting Fixtures Construction of Electric Headlight Combination Gas and Electric Headlights Typical Three-Lamp Lighting System Complete Six-Lamp Three-Circuit Lighting Sys- tem Utility of Windshields Windshield Construction Functions of Shock Absorbers Auxiliary Springs Dampening Spring Ac- tion Motor Car Warning Signals Speed Measuring Devices Tools and Miscellaneous Equipment Small Tool Outfit Outlined Supplementary Useful Tools General Supplies and Spare Parts Car-Raising Jacks How Supplies May Be Carried Kemco Com- bined Fan and Dynamo 647-707 CHAPTER XII Operating Advice and Explanation of Automobile Control Methods How to Start a Gasoline Engine How Motor Speed is Controlled Ma- nipulation of Spark Lever Why Spark Lever is Advanced and Retarded Position of Spark and Throttle Control Levers to Obtain Contents PAGES Varying Speeds Controlling Cars with Friction Transmission Obtaining Varying Speed Ratios with Planetary Gearsets How to Run a Maxwell Car Operating Ford Model T Gear Selection of Brush Runabout Operating Sliding Gearsets How Selective Gears are Shifted Typical Change-Speed Gates Left-Hand Con- trol Typical Speed-Changing Systems General Driving Instruc- tions Suggestions for Oiling Winter Care of Automobiles Anti- Freezing Solutions Spot-Removing Preparations Vulcan Electric Gearshift . 708-744 CHAPTER XIII Practical Hints to Assist in Locating Power-Plant Troubles Systematic Detection of Conditions to which Imperfect Engine Operation Can Be Ascribed Faults of Ignition System Derangements of the Car- buretor Group and Their Symptoms Cooling and Lubrication Group Troubles Summary of Hints 745-757 CHAPTER XIV Keeping Up the Motor-Car Chassis Common Defects of Clutches and Gearsets Faults in Chain- and Shaft-Driving Systems Troubles in Front and Rear Axles Adjustment of Brakes Care of Miscella- neous Chassis Components Maintenance of Body Finish, Tops and Upholstery ' 758-772 CHAPTER XV Elements of Magneto-Electric Phenomena Why Current Flows Action of High Tension Coil Ignition Systems, etc 773-78!) INDEX 790 LIST OF ILLUSTRATIONS CHAPTER I PAGE Fig. 1. Plan View and Side Elevation of Pleasure Car Chassis Propelled by Four-Cylinder Gasoline Motor Showing Important Components and their Relation to Each Other in the Assembly (Plate) . . 46-47 Fig. 2. Plan View Depicting Important Parts of a Prominent English Pleasure Car Chassis in which Power is Furnished by a Six-Cylinder Internal Combustion Engine (Plate) 48-49 Fig. 3. Side Elevation of Sheffield-Simplex Six-Cylinder Chassis; a Typical Design of English Derivation 50 Fig. 4. Plan and Side Elevation of Heavy Commercial Truck Chassis of Foreign Design Showing Essential Elements and Their Location in the Frame (Plate) 50-51 Fig. 5. Plan View of Light American Motor Truck Chassis . . 52 Fig. 6. Side Elevation of Light Truck Chassis Showing Important Mechanism 53 Fig. 7. Front View of Gasoline Pleasure Car Chassis with Section of Radiator Broken Away to Show Placing of Power Plant in Frame 54 Fig. 8. Showing Typical Pressed Steel Frame which Forms the Founda- tion of the Modern Gasoline Automobile Before Placing Parts of the Mechanism 55 Fig. 9. Views Detailing Further Steps in Assembling Typical Gasoline Car Chassis Illustrating Location of Motor and Gear Box . . 56 Fig. 10. How the Pleasure Car Chassis Looks with Rear Axle Installed and Gearset Coupled to Engine 57 Fig. 11. After Driving Shaft, Steering Wheel and Control Levers are Added the Chassis Begins to Assume a Finished Appearance . 58 Fig. 12. Plan View of Chassis when Radiator, Cooling Fan and Muffler Have Been Put in Their Proper Places 59 Fig. 13. The Finished Chassis as It Appears After the Front Wheels, Tires, Traction Wheels, Brake Drums, Running Boards and Finish- ing Touches Have Been Made 60 Fig. 14. Front View of Typical Gasoline Car of Modern Design Showing Parts which Tend to Impede Speed of Car by Producing Air Resist- ance . 63 Fig. 15. Side View of Typical Gasoline Car Demonstrating Influence of Body Form on Air Flow 64 7 8 List of Illustrations PAGE Fig. 16. Plan View Showing Path of Air Currents Around Body of Gasoline Car when No Attempt Has Been Made to Secure Lessened Air Resistance 65 Fig. 17. Depicting Flow of Air Currents Around Torpedo Body Designed to Reduce Friction of Atmosphere at High Speeds ... 66 Fig. 18. Plan View of Vehicle Body Shown in Preceding Illustration which Clearly Indicates Influence of Symmetrical Body Form in Promoting Lessened Air Resistance 66 Fig. 19. Outline of Exaggerated Torpedo Body Type, Seldom Seen Ex- cept on Racing Cars 67 Fig. 20. Typical Modern Roadster Chassis Fitted with Fore Door Body, Showing Application of Stream Line Body Form in Practice . 67 Fig. 21. Application of Fore Door, Five-Passenger Touring Body to Gasoline Car Chassis 68 Fig. 22. The Coupe; a Popular Form of Closed Body Favored by Pro- fessional Men G8 Fig. 23. The Rockwell Taxicab, or Public Service Vehicle, with Con- vertible Type Body, which May Be Used as Shown and which Be- comes a Closed Car when the Top is Raised 69 Fig. 24. One and One-half Ton Capacity White Truck; a Conventional Example of American Commercial Car Having Power Plant Located Under the Hood, as in Pleasure Car Practice 70 Fig. 25. Front and Rear Elevation of Special Sampson Truck, Designed for United States Army Service 71 Fig. 26. Side View of Sampson Army Type Transport Wagon . 71 Fig. 27. Showing Typical American Motor Truck Design in which Power Plant is Placed Under Operator's Feet, thus Providing More Carrying Space for Body without Lengthening Wheel Base . 72 Fig. 28. Motor Truck Chassis Fitted with Special Body for Fire Depart- ment Service; a New Field to which the Gasoline Motor is Par- ticularly Well Adapted . 72 Fig. 29. Showing Different Body Forms Fitted to Same Chassis Type 73 Fig. 30. Light Motor Truck Chassis which Follows Typical Pleasure Vehicle Design Except in Size of Parts. The Frame and Running Gear are Heavier and Stronger, to Compensate for the Greater Load-Carrying Capacity 74 Fig. 30a. Typical Modern Touring Car with Stream Line Body and Detachable Wire Wheels 75 Fig 30b. The Knox-Martin Tractor, a Mechanical Substitute for the Horse 76 Fig. 30c. Two Methods of Applying the Knox-Martin Tractor to Conven- tional Types of Horse-Drawn Fire Apparatus ..... 78 Fig. 30d. How the Three-Wheel Tractor is Utilized in Connection with Heavily Loaded W T agon Bodies 79 List of Illustrations 9 PAGE Kij,. ;u)p. Demonstrating How the Three-Wheel Tractor with Hook and Ladder Attached Can Turn in a Narrow Street .... 80 Fig. 30f. How One Tractor May Be made to Serve a Number of Wagon Bodies 81 Fig. 30h. Application of the Hoadley System Two-Wheel Drive and Steer Tractor to Heavy Low Gear 82 Fig. 30g. The Couple Gear Four-Wheel Drive and Steer Tractor At- tached to Large Coal Wagon 83 Fig. 30i. The Jeffery Four- Wheel Drive and Steer Motor Truck Chassis. 84 Fig. 30 j. Forms of Light Cars that May Be Included in the Cyclecar Class 86 Fig. 30k. Plan and Side Elevation of the Marlborough Cyclecar Chassis which is Built on Regular Motor Car Lines, but on a Miniature Scale (Plate) 87-88 Fig. 30-1. Representative Types of True Cyclecars 89 Fig. 30m. Side Elevation of Pilot Light Car Chassis, an English De- sign Employing Friction Disc Drive 91 Fig. 30n. Chassis of Simple Cyclecar Type Showing Location of Com- ponents and Relation to Each Other 93 Fig. 30o. Plan View of the Falcon Cyclecar Showing Staggered Ar- rangement of Seats 94 Fig. 30p. The Avery Farm Truck which is Designed for Carrying Loads or for Use as a Tractor in Hauling Farm Machinery ... 96 Fig. 30q. Side Elevation of the Hackney Auto Plow .... 98 CHAPTER II Fig. 31. Typical Motor Car Power Plant Showing External Appearance and Location of Important Auxiliary Mechanisms .... 101 Fig. 32. Diagram Comparing Action of Four-Cycle Engine with that of Muzzle-Loading Cannon in Order to Simplify Explanation of Cycle of Operations, thus Enabling the Reader to Comprehend this Funda- mental Principle Clearly (Plate) 102-103 Fig. 33. Sectional View One-Cylinder Horizontal Engine Used on Some Reo Models, a Type that is Rapidly being Replaced by Four-Cylinder Motors. These Motors were Operated at Moderate Speed and Had Considerable Vibration if Speeded Up or Run Slowly . . . 107 Fig. 34. Sectional View of Brush Runabout Motor, a Simple Single- Cylinder Power Plant of the Vertical Type, Designed to Operate at High Speeds 109 Fig. 35. Diagrams Illustrating Sequence of Cycles in One- and Two- Cylinder Engines Show More Uniform Turning Effort on Crank- shaft with Two-Cylinder Motors 110 10 List of Illustrations PAGE Fig. 36. Diagrams Demonstrating Clearly Advantages which Obtain when Multiple-Cylinder Motors are Used as Power Plants. The Continuous Power Application Possible Makes for Even Turning Movement and Reduces Vibration 113 Fig. 37. Diagram Showing Actual Duration of Different Strokes in Degrees 116 Fig. 38. Simple Form of Two-Cylinder Motor Having Opposed Cylin- ders; a Very Popular Form of Power Plant for Light Service . 117 Fig. 39. Sectional View of Four-Cylinder Motor, the Most Widely Used Type of Multiple Cylinder Engine 118 Fig. 40. Sectional View of Typical Four-Cycle, Four-Cylinder Engine Showing Important Internal Components and Their Relation to Each Other 119 Fig. 41. Sectional View of Rear Cylinder of Gasoline Engine with Im- portant Parts Indicated 120 Fig. 42. Comparing Poppet Valve and Sliding Sleeve Valve Power Plants. Upper View Shows Knight Engine with Sleeves to Control Gas Ports. Lower Illustration Shows Gas Passages Controlled by Mushroom Valves 122 Fig. 43. Showing Action of Inlet Valve and Cam of Conventional Type. Note Gradual Valve Opening, which Does Not Attain Its Full Value for Some Time 124 Fig. 44. Showing Action of Exhaust Valve of Conventional Motor Type 126 Fig. 45. End Sectional View of Knight Sliding Sleeve Type Motor Showing Sleeves which Take Place of the Poppet Valves of Conven- tional Motors. A Outer Valve Shell. B Inner Valve Shell. C Operating Lever for A. D Operating Lever for B. E Lay Shaft, F Crank Shaft. G Helical Gears. H Valve Opening. K Cyl- inder Head. L Sparking Plug Holes. Cross-shaft Driving Pump and Magneto. U Piston 127 Fig. 46. Diagrams Depicting Action of Sliding Sleeves on Intake Stroke. A Inlet Port About to Open. B Inlet Port Fully Open. C Inlet Port Closed (Plate) 127-128 Fig. 47. Diagrams Illustrating Movement of Sliding Sleeve Valves on the Exhaust Stroke. A Exhaust Port About to Open. B Exhaust Port Fully Open. C Exhaust Port Closed (Plate) . . . 127-128 Fig. 48. Defining Two-Port, Two-Cycle Engine Action . . . . 131 Fig. 49. Showing Three-Port, Two-Cycle Engine Operation . . 133 Fig. 50. Explaining Action of Differential Piston Type of Two-Cycle Engine 135 Fig. 51. Defining Advantages of Unit Power Plant Construction when Supported on Three Points 138 Fig. 52. Four-Cylinder Power Plant and Transmission Unit Adapted for Three-Point Support 139 List of Illustrations 11 PAGE Fig. 53. Six-Cylinder Unit Power Plant Utilized in Knox Motor Car is Supported by Four Points 139 Fig. 54. Views of Typical Power Plant as Installed in Motor Car Frame, the Common Method of Installation in Pleasure Cars . . . 140 Fig. 55. Showing Method of Installing Engine in Light Truck. Seat and Dashboard Units Removed to Illustrate Accessibility of Engine if Extensive Repairs are Necessary 142 CHAPTER III Fig. 56. Illustrating Different Methods of Cylinder Construction Com- monly Employed. A Single or One-Cylinder Casting Used on Jack- son Cars. B Individual Cylinder Forming Part of Knox Power Plant. C Typical Twin Casting Generally Used on Motor Car Engines. D Four Cylinders Cast in One Block, a Feature of the Chalmers " 30 " Motor 144 Fig. 57. Block Casting of Everitt "Six," a Remarkable Innovation in Motor Design Because the Six Cylinders, Upper Part of Crank Case and Inlet and Exhaust Manifolds are Included in One Casting . 146 Fig. 58. Example of Four-Cylinder Block Motor Having One Separately Cast Head Member Common to All Cylinders. A Copper-Asbestos Gasket is Utilized in Making a Gas and Water Tight Joint Between the Parts. Note Accessibility of Pistons and Valves ... 147 Fig. 59. Showing Separable Head Construction of Argyl Sleeve Valve Motor, Made Necessary by Use of Sleeve 149 Fig. 60. Section Through Sheffield Simplex (English) Engine, Presented to Show Excellent Proportions of Water-jacket Spaces and Easy Gas Passages Leading to Valve Chest 151 Fig. 61. Section Through Sizaire-Naudin (French) Motor Showing a Typical Small Bore, Long Stroke Cylinder 152 Fig. 62. End View Humber (English) Motor Depicting Off -set Cylinder Construction 153 Fig. 63. Diagrams Demonstrating Advantages of Off-set Crank Shaft Construction 155 Fig. 64. Part' Sectional View of Sheffield Simplex Six-Cylinder Motor Showing Use of Block Castings, Seven-Bearing Crank Shaft and Other Constructional Details. Note Exceptionally Good Water- jacketing of Cylinders 150 Fig. 65. Section Through Typical Four-Cylinder Block Motor with Three-Bearing Crank Shaft 157 Fig. 66. Sectional View Knox Model R Motor Illustrating Application of Individual Cylinder Castings, Separable Head Members and Five- Bearing Crank Shaft. A Simple and Substantial Design that is En- during and Efficient 158 12 List of Illustrations PAQH Fig. 67. Sectional View of Typical Four-Cylinder Motor Using Indi- vidual Cylinder Castings with Cylinder Heads Cast Integral. Gen- eral Design Fair, Excepting that of Connecting Rods . . . 159 Fig. 68. Illustrating Typical Methods of Valve Installation in Internal Combustion Motors. A Valves on Opposite Sides of T Head Cylinder. B L Head Cylinder Having Intake Valve Placed Di- rectly in the Center of the Cylinder Head 162 Fig. 69. Benz Racing Motor, Presented to Show Method of Valve Placing so These Members Open Directly into the Cylinder Head 163 Fig. 70. Part Sectional View of Bergdoll Motor Showing Placing of Valves. The Exhaust Member is Fitted in a Side Pocket of the L Cylinder. The Inlet Valve is Placed Directly in the Center of the Combustion Chamber 165 Fig. 71. Cylinder Head of Knox Engine Cut in Two to Show Method of Valve Placing and Seating Directly in Separately Cast Member. Valves Operated by Rocker Arms. Note Exceptionally Good Water Spaces Around Valve Seats 166 Fig. 72. Section Through Concentric Valve Used on Some Franklin Models. The Exhaust Valve, which is a Regular Poppet Type, Seats in the Inlet Member, which is a Hollow Shell of Metal. Both Valves Open Directly into the Combustion Chamber . . . 167 Fig. 73. Section Through Cylinder of Hudson Car. A Typical Form Having L Shape Cylinder with Inlet and Exhaust Valves on Same Side of Cylinder and Actuated from Common Cam Shaft. Note Plate Used to Enclose Valve Springs 168 Fig. 74. Types of Valves in Common Use. A One-Piece Steel Valve of Good Design which Permits Easy Gas Flow. B Steel Valve Made by Electrically Welding a Nickel Steel Head to a Carbon Steel Stem. C A Construction Often Employed for Exhaust Valves, a Two- Piece Built-Up Member. D Valve with Flat Seat, Often Used to Admit Mixture to Cylinder 170 Fig. 75. Forms of Valve-Lifting Cams Generally Employed. A Cam Profile for Long Dwell and Quick Lift. B Typical Inlet Cam Used with Mushroom Type Follower. C Average Form of Cam. D Designed to Give Quick Lift and Gradual Closing ... 172 Fig. 76. Showing Principal Types of Cam Followers which Have Re- ceived General Application 173 Fig. 77. Defining Different Possible Methods of Valve Operation. A Overhead Valve Actuated by Rocker Arm, Tappet Rod and Roller Type Cam Follower. B Both Valves Operated from One Cam, T Head Cylinder. C Valves of L Type Twin Cylinder Casting Operated by Mushroom Type Cam Followers. D Suggested Method of Indirect Valve Operation 175 List of Illustrations 13 PAGE Fig. 78. Diagram Showing Forms of Cylinder Demanded by Different Valve Placings. A T Head Type, Valves on Opposite Sides. B L Head Cylinder, Valves Side by Side. C L Head Cylinder, One Valve in Head, Other in Pocket. D Inlet Valve Over Exhaust Member, Both in Side Pocket. E Valve-in-the-Head Type with Vertical Valves. F Inclined Valves Placed to Open Directly into Combustion Chamber . 177 Fig. 79. Cam Shaft and Valve Operating Plunger Case of Hupp Motor, a Separate Member. Note Simple Type of Cam Follower . . 178 Fig. 80. Front View of Warren-Detroit " 30 " Motor with Timing Gear Case Cover Removed to Show Arrangement of Cam Shaft and Water Pump Driving Gears 180 Fig. 81. Showing Use of Silent Chain Connection Between Crank Shaft and Cam Shaft, and also for Driving Water Pump and Magneto Shafts. A Chain Drive on Wolseley (English) 1912 Motor. B Method of Using Silent Chains on White & Poppe ( English ) Power Plant 181 Fig. 82. Section Through Cylinder of Knight Motor Showing Important Parts of Valve Motion 183 Fig. 83. Diagram Showing Relative Movement of Sleeves and Cam Shaft of Knight Type Motor. Note Port Opening at Various Piston Posi- tions. Shaded Portions of Sleeves Represent Ports . . . 184 Fig. 84. Sectional Views Showing Action of Miesse Combination Sleeve and Piston Valve at Different Points in Cycle of Engine Operation 186 Fig. 85. Defining Action of Peculiar Rotary Valve Used in Latest Itala (Italian) Motor 188 Fig. 86. Partial Section of Reynolds Rotary Valve Motor Cylinder Showing Method of Rotating Simple Disc Valve and Ports in Cylinder Head 189 Fig. 87. Part Section of Reynolds Rotary Valve Motor Showing Prac- tical Application of Ported Disc in Controlling Gas Passages. Note Compact Design of Cylinder Block and Two-Bearing Four-Throw Crank Shaft 191 Fig. 88. Unconventional Forms of Rotary Valve Motors Designed to Meet the Present Day Demand for Silent Valve Action. A Mead Motor Using Two Revolving Cylindrical Valves, One at Each Side of Cylinder. B Single Ported Cone Valve. C Application of Two Single Ported Cones, One Superposed. D Use of Distinct Valves, One for Inlet Port, the Other to Govern Exhaust Passage . . 192 Fig. 89. Part Section of Sphinx Valveless Motor in which Poppet Valves are Replaced by a Split Ring which Reciprocates in the Cylinder Head, Opening and Closing the Gas Ports as It Moves Up and Down. A Inlet Ports Open. B and C All Ports Closed. D Exhaust Ports Open 194 14 List of Illustrations PAGE Fig. 90. Diagrams Illustrating Action of Darracq (French) D Form Eotary Valve Motor. A Piston at Beginning of Induction Stroke. B Piston at Inception of Compression Stroke. C Piston in Posi- tion for Receiving Explosion Impact. D Valve Position at Start of Exhaust Period 196 Fig. 91. Section of Hewitt Piston Valve, Motor Cylinder and Valve Chest 198 Fig. 92. Hewitt Piston Valve Motor Action Outlined Graphically. A Suction Stroke. B Compression. C Explosion. D Exhaust . 199 Fig. 93. Diagram Showing Different Valve Timing Methods . . 206 Fig. 94. Diagram Showing Method of Marking Fly-wheel Circumference to Obtain Proper Timing of Typical Four-Cylinder Motor . . 208 Fig. 94a. Sectional View of the Julian Engine which Employs a Pecu- liar Valve Arrangement 210 Fig. 94b. Part Sectional View of the Fischer Slide Valve Motor . 212 CHAPTER IV Fig. 95. Forms of Pistons Commonly Employed in Gasoline Engines. A Dome Head Piston with Three Packing Rings. B Flat Top Form Almost Universally Used. C Concave Piston Utilized in Knight Motors and Some Having Overhead Valves. D Two-Cycle Engine Member with Deflector Plate Cast Integrally. E Differ- ential or Two-Diameter Piston Used in Some Engines Operating on Two-Cycle Principle 215 Fig. 96. Typical Methods of Piston Pin Retention Generally Used in Engines of American Design. A Single Set Screw and Lock Nut. B Set Screw and Check Nut Fitting Groove in Wristpin. C, D Two Locking Screws Passing into Interior of Hollow Wristpin. E Split Ring Holds Pin in Place. F Use of Taper Expanding Plugs Outlined. G Spring Pressed Plunger Type. H Piston Pin Pinned to Connecting Rod. I Wristpin Clamped in Connecting Rod, Small End by Bolt 217 Fig. 97. Types of Piston Rings and Ring Joints. A Eccentric Ring. B Concentrically Machined Form. C Lap Joint Ring. D Butt Joint, Seldom Used. E Diagonal Cut Member, a Popular Form 219 Fig. 98. Showing Flat Top Piston Provided with Four Concentric Rings, One of the Packing Members and the Wristpin with Its Bushing 220 Fig. 99. Typical Connecting Rod and Its Wristpin. Lower Bearing Cap Held by Four Bolts. White Metal Boxes in Cast Bronze Rod . 221 Fig. 100. Connecting Rod Types Summarized. A Simple Connecting Rod Made in One Piece, Usually Fitted in Small Single-Cylinder Engines Having Built-up Crank Shafts. B Marine Type, a Pop- ular Form on Heavy Engines. C Conventional Automobile Type, a List of Illustrations 15 PAGE Modified Marine Form. D Type Having Hinged Lower Cap and Split Wristpin Bushing. E Connecting Rod Having Diagonally Divided Big End. F Ball Bearing Rod. G Sections Showing Structural Shapes Commonly Employed in Connecting Rod Con- struction . 223 Fig. 101. C'rank Shaft, Piston and Connecting Rod Assembly Used in Reo Motors 224 Fig. 102. Some of the Components of Corbin " 40 " Motor. A Piston and Connecting Rod Assembly. B Inlet and Exhaust Cam Shafts. C Twin Cylinder Casting . . . 225 Fig. 103. Typical Cam Shaft with Valve Lifting Cams and Gears to Op- erate Auxiliary Devices Forged Integrally 226 Fig. 104. Auxiliary Shaft Used in Connection with Cam Shaft Driven from a Spiral Gear Turns Tinier and Oil Pump . . . 227 Fig. 105. Showing Method of Making Crank Shaft: A The Rough Steel Forging Before Machining. B The Finished Six-Throw, Seven-Bearing Crank Shaft 228 Fig. 106. Defining Built-up Crankshaft Construction Sometimes Used in Small Motors . . . ... .... . . 229 Fig. 107. Showing Form of Crank Shaft for Twin-Cylinder Opposed Power Plant 230 Fig. 108. Two Forms of Four-Cylinder Crank Shaft. A Five-Bearing Type with Fly-wheel Fastening Key at Front End. B Three-Bea/- ing Type with Flange for Securing Fly-wheel Formed Integral . 230 Fig. 109. Representative Three-Bearing Crank Shafts. A For Use with Cylinders Cast in Pairs. B Used with Individually Cast Cylin- ders. Note Round Section Portions Connecting Ends to Center Crank Throws 231 Fig. 110. Bottom View of Premier Engine Showing Four-Bearing Six- Cylinder Crank Shaft with Connecting Rods in Place ... 232 Fig. 111. Design of Four-Cylinder Crank Shaft Mounted on Two An- nular Ball Bearings. Note Method of Fly-wheel Retention by Key and Taper and Bearing Housing 232 Fig. 112. Four-Throw, Two-Bearing Chalmers Crank Shaft Mounted on Anti-Friction Journals of the Ball-Bearing Type .... 233 Fig. 113. Four-Throw, Three-Bearing Lozier Crank Shaft and Connecting Rod Assembly Mounted on Three Large Annular Ball Bearings. Note Connecting Rod Design and the Use of Plain Bearings at Both Wristpin and Crankpin Ends 234 Fig. 114. Typical Fly-wheel Showing Female Member of Cone Clutch and Fan Blade Spokes. Rim is Light Because of Large Diameter 236 Fig. 115. Rear View of Overland Power Plant Showing Fan Blade Spoke Fly-wheel Construction 237 16 List of Illustrations PAGE Fig. 116. Outlining Methods of Fly-wheel Retention Commonly Used. A By Gib Key. B By Woodruff Key, Taper and Clamp Nut. C By Bolting to Flange Forged Integrally with Crank Shaft . 239 Fig. 117. Showing Method of Marking Rim of Six-Cylinder Fly-wheel for Guiding Repairman or Motorist to Retain Correct Valve Timing 240 Fig. 118. Crank Case of Reo Four-Cylinder Motor, a Barrel Type with Ends Closed by Plates which Support Crank Shaft ... 242 Fig. 119. Crank Case of Corbin " 40 " Power Plant Made in Two Halves. Crankshaft Bearings and Caps Secured to Upper Half, which also Has Supporting Arms Cast Integral. Lower Portion of Crank Case Simply Acts as Oil Container. This is the Common Construction 243 Fig. 120. Bottom View of Inter-State Power Plant. Crank Case a Barrel Form with Removable Bottom Plate to Permit Access to Engine Interior. Important Power Plant Parts Clearly Shown . . 244 Fig. 121. Top Half of Knox Crank Case. Xote Method of Supporting Five-Bearing Crank Shaft and Substantial Yoke Encircling Space for Fly-wheel and Serving to Hold Transmission Gearing to Form Unit Power Plant 245 Fig. 122. Sectional Views of Amplex Two-Cycle Motor Cylinder. A Piston at Top of Stroke, Ready to Receive Impact Due to Gas Ex- plosion. B Piston at Bottom of Stroke. Note Gas Transfer From Engine Base and Expulsion of Burnt Gases .... 247 Fig. 123. Sectional View Showing Construction of Legros (French) Motor Denning Peculiar Cylinder Construction . . . . 249 Fig. 124. The Cote (French) Two-Cycle Motor is a Good Example of the Type Employing a Two-Diameter Piston and Distributor Valve 250 Fig. 125. The Rayner (English) Two-Cycle Motor Employs Distinctive Double-Piston Arrangement. A Side View Showing Crank Shaft and Connecting Rods. B End Section Showing Relative Angu- larity of Connecting Rods. C Inner Piston Uncovers Inlet Ports, Outer Piston Covers Exhaust Passages 251 Fig. 126. Inlet Side of Typical Four-Cylinder Power Plant Showing Carburetor and Magneto Placing 253 Fig. 127. Exhaust Side of Four-Cylinder Power Plant Showing Water Pump Location 254 Fig. 128. Valve Side Regal Motor Showing Compactness of Design Pos- sible with L Cylinder Construction. Note Manifold Placing and Magneto and Carburetor Location . . . . : . . . 254 Fig. 129. Exhaust Side of Columbia " Mark 85 " Motor. Note En- , closed Valve Springs and Arrangement of Parts .... 255 Fig. 130. Inlet Side of Matheson " Silent Six " Power Plant, an Over- Head Valve Type 256 List of Illustrations 17 PAGE Fig. 131. View of Eight-Cylinder Hendee Motor, a Type Seldom Used on Motor Cars, but Popular for Aviation. Eight-Cylinder Mo- tors Designed for Automobile Propulsion are Always of the V Type, which Permits Compactness and No Greater Overall than the Usual Four-Cylinder Power Unit 257 Fig. 131a. Part Sectional View of the De Dion Eight-Cylinder "V" Type Automobile Motor 258 Fig. 13 Ib. Front and Side Views of the Spacke De Luxe Cyclecar Motor 260 Fig. 131c. A Two-Cylinder Vertical Engine of English Design. A Type Used on Some Foreign Cyclecars 261 Fig. 131d. Part Sectional View of the Maxwell "25" Motor which is Representative of the Class Using Detachable Cylinder Head Cast- ings . 262 CHAPTER V Fig. 132. Illustratirg Method of Storing Fuel in Brush Runabout, which Permits Short and Direct Gasoline Piping 275 Fig. 133. Denning the Usual Methods of Fuel Storage in Motor Cars. A Oval Tank Back of Seat. B Round Tank at Rear of Chassis, Common on Racing Cars. C Container Under Front Seat, the Conventional Method. D Tank at Rear of Frame, Underslung, which Makes Pressure Feed Necessary 276 Fig. 134. Complete Fuel System Used on Some Models of Peerless Cars, Showing Method of Supplying Carburetor with Fuel and Joining It to Cylinders 278 Fig. 135. Unconventional System in which a Pump is Depended Upon to Draw Fuel from Container and Deliver It to Vaporizer . . 279 Fig. 136. First Forms of Gasoline Vaporizers. A An Early Wick Car- buretor. B Type in which Air is Drawn Through Fuel to Charge It with Explosive Vapor . . . 281 Fig. 137. Marine Type Mixing Valve, by which Gasoline is Sprayed into Air Stream Through Small Opening in Air Valve Seat . . . 283 Fig. 138. Lanchester Wick Feed Carburetor. The Only Modern Adapta- tion of Earlier Forms 284 Fig. 139. Tracing Evolution of Modern Spray Carburetor. A Early Form Evolved by Maybach. B Phoenix-Daimler Modification of Maybach's Principle. C Modern Concentric Float Automatic Com- pensating Carburetor 286 Fig. 140. Showing Common Forms of Mixing Chambers and Spray Noz- zle Locations 200 Fig. 141. Types of Float Chambers in Common Use Defining Various Methods of Controlling Fuel Supply Valve 292 Fig. 142. Spray Nozzle Forms and Methods of Supplying Auxiliary Air to Modern Carburetors . . 294 18 List of Illustrations PAGE Fig. 143. Showing Method of Regulating Fuel Mixture Supplied the Cyl- inders by Means of Centrifugal Governor, which Automatically Re- duces the Quantity when Engine Speed Exceeds a Certain Predeter- mined Limit 296 Fig. 144. Schebler Carburetor Construction Outlined. This is One of the Simplest Forms that Have Been Used Extensively .... 298 Fig. 145. Kingston Automatic Carburetor Admits Auxiliary Air Through Ball-Controlled Ports at Side of Mixing Chamber . . 299 Fig. 146. Holley Carburetor with Spring Controlled Poppet Valve to Regulate Auxiliary Air Passage 300 Fig. 147. Latest Model of Holley Carburetor with By-Pass Tube to Pro- vide Easier Starting 302 Fig. 148. Mercedes Carburetor, which Has Retained Substantially the Same Form as when First Designed Nearly a Decade Ago . . 303 Fig. 149. Sectional View of Chapin Carburetor, which Has Mechanical Control of Auxiliary Air Opening and Spray Nozzle Needle . 304 Fig. 150. Sectional View of Excelsior Carburetor. A Side Section De- picting Floating Ball Controlling Mixture Passage. B Showing Peculiar Air Valve Spring and Geared Control of Air Valve Stem 305 Fig. 151. Views of the Efficient Vaporizer Used on Pierce- Arrow Cars, Showing Method of Fuel Regulation, Auxiliary Air Control by Reeds, and Mixture Supply Regulation by Cylindrical Throttle Valve 307 Fig. 152. Grouvelle and Arquemburg (French) Carburetor with Venturi Tube Mixing Chamber and Air Port Control by Floating Balls . 308 Fig. 153. Peerless Carburetor, which is Combined with Induction Mani- fold. Has Spray Nozzle and Float Chamber at Bottom and Air Valve at Top 310 Fig. 154. Showing Details of Breeze Carburetor, a Simple, Automatic Instrument. Note Fuel Adjustment by Needle Valve Over Spray Nozzle 312 Fig. 155. Details of Stromberg Double-Jet Carburetor, which Provides Extra Fuel Through Auxiliary Spray Jet when Motor Demands It 313 Fig. 156. Carburetor Incorporated in F. I. A. T. Cylinder Casting is a Multiple- Jet Type Having Two Spray Tubes 314 Fig. 157. Denning Principles of Construction Incorporated in Saurer Economy Carburetor, a Two-Jet Form Having Automatic Control of Mixture 316 Fig. 158. The Zenith Carburetor, which Embodies Novel Application of Double-Jet Principle, One Spray Nozzle Being Concentric with the Other 318*- Fig. 159. Types of Strainers Interposed Between Vaporizer and Gasoline Tank to Prevent Water or Dirt Passing Into Carbureting Device 320 List of Illustrations 19 PAGE Fig. 160. Holley Combined Gasoline and Kerosene Carburetor May Be Used with Either Fuel Though Specially Adapted for the Less Vola- tile Liquid Distillates of Petroleum, Because of Preheating Ar- rangement 322 Fig. 161. Combined Intake and Exhaust Manifold Suggested as Suit- able for Use with Kerosene and Air Mixture. The Hot Exhaust Gases Heat the Inlet Pipe Walls and Produce More Complete Va- porization 323 Fig. 162. Showing Two-Cycle Motor with Device for Direct Injection of Heavier Petroleum Distillates into Cylinder 325 Fig. 163. Typical Induction Pipes Used on Four-Cylinder Motors . 328 Fig. 164. Conventional Inlet Manifolds Adapted for Six-Cylinder Motors 329 Fig. 165. Some Unconventional Forms of Gas Supply Pipes Used on Six-Cylinder Power Plants 330 Fig. 166. Holley Method of Compensating for Temperature Variations and Securing Easy Starting from Dash-Adjusted Regulator. Posi- tions of Regulator Valve Sleeve for Different Conditions Outlined 332 Fig. 167. Muffler Forms Adapted to Reduce Pressure of Exhaust Gases Before Discharging Them 334 Fig. 168. Water-Cooled Muffler Used when Exceptional Silence is De- sired. Often Applied in Marine Service 336 Fig. 169. Suggested Exhaust Manifold in which Ejector Action of Ex- haust Gases Under High Velocity is Said to Reduce Back Pressure on Pistons 337 Fig. 170. How Muffler Cut-out Valve is Arranged on Wolseley (English) Cars to Reduce Noisy Direct Exhaust 338 Fig. 170a. Sectional View of Typical Kerosene Vaporizer Employing Water Spray to Insure Combustion of Kerosene Vapor . . . 340 Fig. 170b. The Holley Kerosene Vaporizer in Section .... 342 Fig. 170c. Gasoline Carbureter Used in Connection with Holley Kerosene Vaporizer for Starting Purposes 343 Fig. 170d. A Bi-Fuel Carburetor of English Design .... 344 Fig. 170e. Vaporizer of French Design Adapted for Use with Either Gasoline or Camphor Fuel 346 Fig. 170f. Part Sectional View Showing Construction of One Type of Carburetor Used in Ford Cars 347 Fig. 170g. The Muir Carburetor with Mechanically Controlled Fuel Valve 349 Fig. 170h. The Winton-Stromberg Carburetor Utilizes a Double Spray Nozzle 350 Fig. 170i. Section of the Scott-Robinson Carburetor: an English Design 351 20 List of Illustrations CHAPTER VI PAGH Fig. 171. Simple Primary Cells Used to Produce Electric Current. A Form to Show Principle of Current Production by Chemical Ac- tion. B Dry Cell, the Type Suitable for Automobile Service . 355 Fig. 172. Methods of Joining Dry Cells to Form Batteries of Varying Value 357 Fig. 173. Types of Accumulators or Storage Batteries. A Simple Form of Cell. B Battery Composed of Three Cells, Such as Commonly Used for Motor Car Engine Ignition 360 Fig. 174. Gray & Davis Governed Dynamo, an Appliance for Producing Electricity by Mechanical Means 365 Fig. 175. Distinctive Form of Current Producer Used on Ford Cars is Incorporated in the Power Plant Fly-Wheel 366 Fig. 176. Simple Forms of Contact Breakers Used on One-Cylinder En- gines. A Wipe Contact. B Touch Contact .... 369 Fig. 177. Timers Employed on Four-Cylinder Engines. A Four-Contact Device for Commutating Primary Current. B Combined Timer and Distributor Directs Both High and Low Tension Energy . 370 Fig. 178. Showing Disposition of Contact Points on Timers for Differ- ing Numbers of -Cylinders. A One-Cylinder Type. B Arrange- ment for Two-Cylinder Opposed Motor. C Contacts Separated by 90 Degrees in One Direction and 270 Degrees in the Other when Used on Two-Cylinder Vertical Engine with Opposed Crank-Pins. D Three-Cylinder Form. E Suitable for Four-Cylinder Engines. F Type Employed on Six-Cylinder Power Plants .... 371 Fig. 179. Simple Ignition System for One-Cylinder Motor Showing Important Components and Their Relation to Each Other . . 373 Fig. 180. Part Sectional View of Simple Induction Coil, an Important Component of All Battery Ignition Groups and Sometimes Used Avith Magnetos 375 Fig. 181. Conventional Induction Coil Forms. A Coil Unit and Plug Combined. B Simple Box Coil for One-Cylinder Ignition. C Two-Unit Coil for Two-Cylinder Motors. D Four-Unit Coil for Four-Cylinder Service 377 Fig. 182. Spark Plug Construction Outlined. A Sectional View of Porcelain Plug. B Part Sectional View of Mica Plug . . 379 Fig. 183. Three Forms of Spark Plugs in which Electrodes are Sep- arated by Porcelain Insulation 380 Fig. 184. Methods of Installing Spark Plugs of Conventional Form. A Incorrect Method. B Correct Installation in Valve Chamber i Cap. C Combined with Cylinder Priming Device or Compression Relief Cock 381 List of Illustrations 21 PAGE Fig. 185. Novel Spark Plugs and Accessory Parts. A Spark Gap Designed to be Placed in Series with Plug Electrode and Current Source. B Plug Shell with Glass Insets to Show Spark. C Spark Plug with Waterproof Terminal Cover 383 Fig. 186. Double Pole Spark Plug and Method of Applying It to Obtain Two Sparks in the Cylinder 386 Fig. 187. Assembly View of Four-Cylinder Ignition Group Showing All Devices and Methods of Wiring 387 Fig. 188. Method of Employing Single Coil to Fire Four Cylinders when Secondary Current is Distributed Instead of Battery Energy 388 Fig. 189. Distributor and Coil Ignition Group for Six-Cylinder Motor Showing Order of Firing and Wiring Connections Clearly . . 389 Fig. 190. Low-Tension Igniter Plate by which Spark is Produced in Some Locomobile Engine Cylinders. A External View Showing Rocker Arm. B Interior View Depicting Contact Points. C Method of Operation 390 Fig. 191. Low-Tension Ignition System for Four-Cylinder Motor Utilizes Battery and Magneto for Current Production. Note Simple Wir- ing. All Conductors Conveying Low-Tension Current . . . 392 Fig. 192. Simple High-Tension Magneto for One-Cylinder Ignition. A Complete Apparatus Comprising Source of Current and Timing De- vice as Well 393 Fig. 193. How Distributor Contacts are Spaced on Two-, Three-, Four- and Six-Cylinder Magnetos 395 Fig. 194. Partially Dismantled Four-Cylinder Magneto Showing Impor- tant Parts of Current Producing and Distributing Elements . 397 Fig. 195. Simple Wiring Scheme when Four-Cylinder Magneto is Utilized for Gas Engine Ignition. Magneto Members Shown Sep- arate to Facilitate Explanation of Principles of Operation . . 398 Fig. 196. Side Sectional View of Bosch High-Tension Magneto Shows Disposition of Parts. End Elevation Depicts Arrangement of Inter- rupter and Distributor Mechanism . 399 Fig. 197. Wiring Diagram Outlining Method of Combining Magneto and Transformer Coil to Form Device for Four-Cylinder Ignition . 400 Fig. 198. Defining Construction of Connecticut Magneto, a Form in which Transformer Coil is Placed Between Magnets Above Arma- ture Tunnel 401 Fig. 199. Showing Application of High-Tension Principle in K.W. Four- Cylinder Magneto 402 Fig. 200. K.W. High-Tension Magneto, a Distinctive Form Utilizing Stationary Winding and Revolving Inductor Elements to Produce Current for Ignition 403 Fig. 201. Typical American Magneto Forms. A Heinze Machine with Round Section Field Magnets. B Kingston Magneto for Dual Igni- 22 List of Illustrations PAGB tion. C Clean-Cut Design of Connecticut Device. D Splitdorf Double Distributor Form .Designed for Two-Spark Ignition Systems 405 Fig. 202. Conventional Methods of Placing and Driving Magneto Genera- tors. A System Used on Regal Engine. B Magneto is Driven from Pump Shaft Extension on Velie Motors 406 Fig. 203. Simple Methods of Holding Magneto in Place on Engine Base to Permit of Easy Removal of Apparatus when Desired . . . 408 Fig. 204. The Ford Magneto is Integral with Engine Base, and Revolv- ing Magnets are Attached to Fly-wheel. Thus Direct Drive from Crank Shaft is Possible Without Gears 409 Fig. 205. Double Ignition System Utilizing Battery and Induction Coil Group for Starting -and Emergency Service, and Pittsfield High Ten- sion Magneto as the Main Ignition System 410 Fig. 206. Practical Application of Double Ignition System to Four- Cylinder Power Plant 411 Fig. 207. Method of Applying Bosch Dual Ignition System to Conven- tional Four-Cylinder Power Plant 412 CHAPTER VII Fig. 208. Showing Use of Magnifying Glass to Demonstrate that Ap- parently Smooth Metal Surfaces May Have Minute Irregularities which Produce Friction 415 Fig. 209. Simple Gravity-Feed Oil Cups with Glass Body to Show Height of Lubricant in Container, and Sight Gauges to Give Visible Evidence of Amount of Oil Supplied 421 Fig. 210. Positive Mechanical Methods of Supplying Lubricant. A Worm Gear Driven Plunger Pump Oiler. B Gear Pump with High- Pressure Relief Valve 423 Fig. 211. How Oil May Be Supplied to Interior Mechanism of Internal Combustion Motor. A Oil Pick-up Finger on Connecting Rod End Dips into Lubricant and Splashes It Over Interior Parts. B Oil Drops into Channel in Horizontal Connecting Rod and Supplies Bear- ings and Cylinder 424 Fig. 212. Sectional View of Typical Motor Showing Parts Needing Lubrication and Method of Applying Oil by Constant Level Splash System. Note also Water-jacket and Spaces for Water Circula- tion 426 Fig. 213. Sectional View of Part of Rutenber Engine Depicting Method of Driving Oil Pump and Distribution to Bearing Points . . 427 Fig. 214. Oil Distributing System Employed on Stoddard-Dayton Motor Cars 428* Fig. 215. Part Sectional View of Motor Car Engine Showing Oil Dis- tribution by Splashers at the Ends of the Connecting Rods, which Dip into Troughs Disposed Under Them 429 List of Illustrations 23 PAGE Fig. 216. Method of Supplying Oil Under Pressure to Main Bearings, from which It is Directed to Connecting Rods by Passages Drilled in Crank Shaft 430 Fig. 217. Showing Application of Mechanical Oiler having Individual Pumps and Leads to Bearing Points in Connection with Sight-Feed Gauge on Dash ' . . . 431 Fig. 218. Oil Supply System Utilized on Knox Automobile Power Plants has Many Good Features 432 Fig. 219. Constant Level Positive Supply System Used in Columbia " Mark 85 " Motor 433 Fig. 220. Components of Typical Motor Car Cooling Group Utilizing Pump to Maintain Circulation of Liquid. System Shown Used on Peerless Cars with Success 436 Fig. 221. Elements of Typical Cooling Group, Defining Construction of Centrifugal Pump, Cooling Fan and Cellular Cooler . . . 437 Fig. 222. Two Forms of Water Circulating Pumps Representing Current Practice. A Cooling Fan and Water Pump Driven from Common Source by Single Belt; Pump Impeller Placed Directly in Water- Jacket. B Gear Circulating Pump '. 438 Fig. 223. Water Cooling Group Used on Maxwell Automobiles in which Water Circulation is Maintained by Natural Means. A Side View of Power Plant Showing Application of Piping. B Plan View Out- lining Disposition of Parts 439 Fig. 224. Renault Thermo-Syphon System, in which Radiator is Placed in Back of Engine Instead of in Front, as is Conventional Practice. A Showing Method of Utilizing Fan Fly-wheel to Insure Air Cir- culation Through Radiator. B Plan View Depicting Flow of Air Currents Through Cooler 440 Fig. 225. Showing Large Water Manifolds Designed to Secure Positive Circulation by Thermo-Syphon or Natural Methods . . . 441 Fig. 226. Typical Ball-Bearing Hub-Cooling Fan Designed to Create Air Draught Through Radiator and Around Cylinders of Motor Car Power Plant '. 44i> Fig. 227. Air-Cooling System Employed on Cameron Motors Depends upon Air Draught from Fan to Circulate Around Flanges on Cyl- inders and Absorb Excess Heat 443 Fig. 228. Parts of Air-Cooled Cylinder Showing Method of Seating Valves Directly in Detachable Cylinder Head, and Large Flanges on Both Cylinder and Head Member to Largely Increase Effective Radiating Surface 444 Fig. 229. Depicting Section Through Lower Section of One Type of Franklin Engine. Showing Application of Auxiliary Exhaust Valve to Relieve Cylinder of Flaming Gases at End of Power Stroke . 44(5 24 List of Illustrations PAGE Fig. 230. Two Forms of Positive Air Fans Used in Automobile Cooling Systems. A Gear-Driven Three-Blade Fan Utilized to Draw Air Through Winton Radiator. B Blower Member Used on Kelly Air- Jacketed Cylinder Motor 447 Fig. 231. Sectional View of Chase Two-Cycle Engine, a Two-Stroke Form Successfully Cooled by Air Flanges Cast Integral with Cyl- inder 448 Fig. 232. Positive Cooling Method Used on Franklin Automobiles in which Air Currents are Drawn Through Cylinder Jackets by Fly- wheel Fan Suction 449 Fig. 233. Air-Jacketed Frayer-Miller Engine Used in Kelly Trucks Cooled by Air Currents Directed over Cylinders by Positive Air- Blower System 450 CHAPTER VIII Fig. 234. Plan of Components of Power Transmission System of Typ- ical Gasoline Automobile, Depicting Relation of Clutches, Gearset and Driving Gears 453 Fig. 235. Sectional View of Cone Clutch Having Female Member Formed Integral with Fly-wheel Rim 459 Fig. 236. Cone Clutch Design with Female Member a Separate Casting Bolted to Fly-wheel Rim 461 Fig. 237. Typical Cone Clutch Male Members Showing Methods of At- taching Leather Facing to Cone Castings. A Pope-Hartford Clutch Cone Faced with Leather and Cork Inserts. B White Cone Uses Leather Band Held in Place by T Bolts 462 Fig. 238. Cone Clutches of English Design. A Metal-to-Metal Surfaces in Oil-tight Case. B Method of Holding Parts in Contact with Ad- justable Springs 463 Fig. 239. Columbia Clutch Employs Friction Shoes to Grip Fly-wheel Before Cone is Fully Engaged, to Secure Gradual Application of Power 465 Fig. 240. Three-Plate Clutch Utilized on Knox Motor Cars Uses a Cen- tral Driven Plate Studded with Cork Inserts 467 Fig. 241. A Three-Plate Clutch Equipped with Friction Brake to Arrest Motion of Driven Member when Clutch is Released .... 468 Fig. 242. Five-Plate Clutch which Employs Two Driving Members Attached to Fly-wheel and Three Driven Plates .... 469 Fig. 243. Typical Multiple Disc Clutch Assembly. The Form Illus- trated is Used on Some of the Hudson Cars 472 Fig. 244. Multiple Disc Clutch Utilized on Franklin Automobiles is Housed in Blower Fly-wheel. Parts are Shown Separated to Make Construction Clear 473 List of Illustrations 25 PAGE Fig. 245. Clutch of Premier Cars Uses Multiple Discs Studded with Cork Inserts as Driving Members, and Plain Metal Plates as Driven Elements 473 Fig. 246. Outlining Action of Simple Face Friction Gearing, which Combines Clutching and Speed-Changing Functions . . . 476 Fig. 247. How Face Friction Gearing is Installed in Motor Car Chassis. A Arranged for Shaft Drive. B Power Transmitted to Wheels by Side Chains 478 Fig. 248. Disposition of Important Elements of Simple Face Friction Gearing Adapted for Single Chain Drive 479 Fig. 249. Sectional View of Simple Planetary Gearset .... 481 Fig. 250. Demonstrating Action of Epicycle Gearing. A The Slow Speed Gear Assembly. B Gears and Pinions Used for Reverse Drive 482 Fig. 251. Planetary Gearing Utilizing Only Spur Gears Carried in Oil- tight Case 483 Fig. 252. Two-Speed and Reverse Planetary Gear Employed on Ford Automobiles 484 Fig. 253. Part Sectional View of Cotta Individual Clutch Transmission Designed for Heavy Motor Truck 486 Fig. 254. Individual Clutch Transmission Using Silent Chain Connec- tion Between Main and Countershafts for Forward Speeds and Slid- ing Spur Gears for Reverse Action 487 Fig. 255. Sectional View of Individual Clutch Gearset with Silent Chains Removed to Show Arrangement of Gearing .... 488 Fig. 256. Arrangement of Gears in Progressive Sliding Gearset . . 490 Fig. 257. Showing Application of Two Shifting Members on Main Shaft of Selective Sliding Gear Speed-Changing Mechanism . . . 491 Fig. 258. Comparing Progressive and Selective Gearset Action to Dem- onstrate Advantages of the Latter Form 492 Fig. 259. Three-Speed Selective Gearset in which All Speeds are Ob- tained by Gears, Xo Direct Lack Being Provided for High Speed 495 Fig. 260. Arrangement of Gears and Shafts in Typical English Three- Speed Selective Gear Box 496 Fig. 261. White Four-Speed Gearset Has Direct Drive on Highest Ratio 496 Fig. 262. Winton Four-Speed Gearset Provides Direct Drive on Third Speed and Gears Up for Highest or Fourth Speed Ratio . . 497 Fig. 263. Conventional Methods of Installing Gearsets in Chassis. A Combined with Engine to Form Unit Power Plant. B Fitted as an Individual Unit Back of Engine. C Combined with Rear Axle. D Mounted at Front End of Driving Shaft Housing . 498 Fig. 264. Clutch and Gearset Portion of Unit Power Plant Showing Positive Alignment Between Clutch and Gearset Main Shaft . 499 26 List of Illustrations PAGE Fig. 265. Herreshoff Unit Power Plant Partially Dismantled to Show Clutch and Gearset Construction 500 Fig. 266. Change-Speed Gearing Combined witli Countershaft for Side Chain Drive 501 Fig. 267. Countershaft and Three-Speed Selective Sliding Gearset Mounted as a Unit Insures Positive Alignment of Speed- Changing and Power-Transmitting Elements 502 Fig. 268. Unconventional Arrangement of Three-Speed Selective Sliding Gearset in Combination with Rear Axle to Secure More Compact Construction by Housing Change Speed and Driving Gearing in Common Case 503 Fig. 269. Usual Arrangement of Change Speed and Driving Gearing at Differential Housing of Live Rear Axle or Countershaft . . 504 Fig. 269a. Special Gearset with Integral Reduction Gearing for Four- Wheel Drive Truck 506 Fig. 269b. Plan View of Chassis of Four-Wheel Drive Truck . . 507 Fig. 269c. Amoskeag Steam Fire Engine Attached to Hoadley System Tractor 509 Fig. 269d. Principal Parts of Hoadley System Tractor. A Power Plant and Generator Assembly. B The Combined Driving and Steering Axle Showing Method of Supporting Wheel Drive Motors 511 Fig. 269e. Depicting the Important Parts of the Wheel and Motor As- sembly Used on the Hoadley Combination Gasoline Electric Drive Tractor 513 Fig. 269f. Power Plant of the Couple Gear Combination Gasoline- Electric Drive Trucks 515 Fig. 269g. Outlining Construction of the Wheel Used on Couple Gear Vehicles. Note the Location of the Driving Motor in the Center of the Wheel and Method of Driving 517 Fig. 269h. Front View of Couple Gear W T heel with Tire and Rim Re- moved to Show Method of Driving by Bevel Pinions and Racks . 518 Fig. 270. Conventional Gasoline Automobile Chassis Forms. A Type in which Frame is Mounted Over Axles, the Usual Construction. B Underslung Chassis, in which Frame is Suspended Beneath Axles (Plate) 520-521 CHAPTER IX Fig. 271. Advantage of Low Weight Placing and Carrying Center of Gravity Near the Ground. A Low Center of Gravity Makes for Stability. B. High Center of Gravity Unsafe .... 521 Fig. 272. Conventional Form of Pressed Steel Automobile Frame with Cambered Side Members 523 Fig. 273. Frame Forms Having Raised Side Members. A Frame Side Raised Over Axle. B Framework with Drop Side Member . 524 List of Illustrations 27 PAGE Fig. 274. Springs Usually Employed for Supporting Motor Car Frames and Horse-Drawn Vehicle Bodies 527 Fig. 275. Spring Suspension Means for Front Ends of Motor Car Frames. A Semi-elliptic. B Full Elliptic of Franklin Car. C Single Cross Spring of Ford Design 528 Fig. 276. Spring Suspensions for Rear Ends of Motor Car Chasses. A Single Elliptic Cross Spring of Ford Cars. B Semi -elliptic Side Member. C Rear Support by Full Elliptic Spring. D Platform Spring Construction. E Three-Quarter Elliptic Application . 529 Fig. 277. Unconventional Spring Suspensions. A Double Semi-elliptic Used on Winton Cars. B Coil Spring and Shock Absorber Com- bination of Liberty-Brush Runabouts 532 Fig. 278. Methods of Steering Vehicles Outlined. A Horse-Drawn Wagon Directed by Swinging Axle. B Motor Car Steered by Mov- able Wheels on Fixed Axle 534 Fig. 279. How Front Wheels of Motor Cars are Moved. A Conven- tional Worm-Gear Reduction Steering Arrangement. B Simple Rack and Pinion System Used on Light Cars .... 536 Fig. 280. Unconventional Steering Gear Employing Threaded Steering Post and Movable Nut with Rack to Engage Sector on Steering Arm Shaft 537 Fig. 281. Construction of Worm and Worm-Gear Reduction Gearing for Steering Purposes 539 Fig. 282. Typical Steering Post Assembly Showing Hand Wheel and Motor Controlling Levers. Sectional View of Worm and Worm Wheel and Steering Arm Connecting Member 540 Fig. 283. Typical Front Axle Types. A Forging of I Section. B Tubular Axle 542 Fig. 284. Typical Front Hub and Steering Knuckle Designs. A Elliot Type Hub with Taper Roller Bearings. B Front Hub Mounted on New Departure " Radax " Ball Bearings. C Mercedes Type Steer- ing Knuckle, Hub Mounted on Single and Double Row Bearings . 543 Fig. 285. Methods of Power Transmission Employed by Motor Car De- signers. A Single-Chain Drive from Planetary Gearset to Live Rear Axle. B Side Chain System. C Drive by Exposed Shaft Having Two Universal Joints. D Drive Shaft Enclosed in Torque Tube Needs but One Universal Joint 545 Fig. 286. Chassis of Knox Car, in which Straight-Line Driving Shaft is Utilized, which Permits Power Transmission with but Minimum Loss 546 Fig. 286a. Side Elevation of the Jeffery Four-Wheel Drive Truck Show- ing Method of Drive from the Change-Speed Gearing to the Axles 547 Fig. 286b Details of Special Gearset Used in Jeffery Four-Wheel Drive Truck 548 28 List of Illustrations PAGE Fig. 286c. Sectional View of Wheel of Jeffery Truck Showing Method of Drive by Spur Gearing 550 Fig. 286d. Details of the Jeffery Four-Wheel Drive Construction. A Axle End with Wheel Removed to Show Driving Gear. B Arrange- ment of Differential Case and Universal Joints on Drive Axle . 551 Fig. 286e. Sectional View of Front Portion of English Motor Truck Chassis Employing Front Wheel Drive 552 Fig. 286f. Plan View of Front Wheel Drive Truck Showing Location of Power Plant, Countershaft Assembly and other Parts . . . 553 Fig. 286g. How Power May Be Transmitted to a Combined Driving and Steering Wheel without Universal Joints 555 Fig. 287. Rear Axle Types Generally Used. A Live Rear Axle Using Shafts which Transmit Power and also Carry Weight, Equipped with Roller Bearings. B Full Floating Type Bevel Gear Drive Axle. C Stationary Axle with Chain Drive to Free Wheels . 557 Fig. 288. Combined Live and Stationary Axle which Combines Good Features of Both Types and Eliminates All Objections to Either. The Strongest Possible Construction 558 Fig. 289. Illustrating Differential Gear Action when Applied to Bevel Gear Drive Axle 560 Fig. 290. Bevel Gear Drive Assembly of Ford Light Cars Mounted on Hyatt Flexible Roller Bearings 562 Fig. 291. Bevel Gear Drive Assembly Mounted on Timken Tapered Roller Bearings 563 Fig. 292. Worm Gear Driving Assembly Utilized on Pierce Motor Trucks and Form of Worm and Worm Wheel Utilized in Power Trans- mission 564 Fig. 293. Worm Gear Driving Axle Used on Dennis (English) Motor Cars 565 Fig. 294. Method of Enclosing Driving Chain in Oil-tight Casing to Secure Efficient Driving and Long Life of Mechanism . . . 566 Fig. 295. Sectional View of Torbensen Axle for Motor Trucks which Combines Features of Both " Live " and " Dead " Rear Axle Forms and which Utilizes Two Driving Gearing Sets 567 Fig. 296. Live Rear Axle with Combined Bevel and Spur Gear Final Drive 567 Fig. 297. Simple Form of Shoe Brake Used on Horse-Drawn Vehicles 569 Fig. 298. Internal and External Band Brakes Used on Motor Car Wheels 570 Fig. 299. Typical Automobile Brake Forms. A Two Internal Bands. B Double Expanding Type. C External and Internal Brake Combination ............ 571 Fig. 300. Typical Automobile Brake Assembly with Rear Wheel Re- moved to Show Application of Brake Drum to Wheel and Internal and External Bands on End Axle 572 List of Illustrations 29 PAGE Fig. 301. Rear Hub of Metz Car Showing Multiple-Disc Brake . . 573 Fig. 302. Types of Front Wheel Brakes that Have Been Used on British Automobiles Showing Novel and Ingenious Methods of Brake Actuation 576 Fi.tr. 302a. The Packard Skew Bevel Driving Gearing .... 578 Fig. 302b. Outlining Construction of the Austin Two-Speed Direct Driv- ing Gearing Used on Rear Axle 570 Fig. 302c. Outlining Two Practical Methods of Locking Differential Gear . 582 Fig. 302d. Practical Application of Worm Gear Drive to Live Axle of English Design 584 Fig. 302e. Part Sectional View of the Lyons-Knight Automobile Show- ing Practical Application of Knight Motor and Worm Gear Drive 585 Fig. 302f. Plan View of the Pilot Light Car Chassis Utilizing Friction Disc Change-Speed Gearing and Single-Chain Drive to Live Rear Axle 586 CHAPTER X Fig. 303. Wooden Portions of Artillery Type Automobile Wheel . 580 Fig. 304. Complete Artillery Wheel Assembly ...... 590 Fig. 305. Wire Spoke Automobile Wheel Modified from Bicycle Prac- tice 593 Fig. 306. Steel Resilient Wheel Having Coil Springs Separating Hub and Rim Members 594 Fig. 307. Spring Wheels Designed to Provide a Resilient Support for Automobiles Without Using Pneumatic Tires 595 Fig. 308. Comparison of Action of Pneumatic and Solid Rubber Tires whi-n Wheel Rides Over Obstacle 597 Fig. 309. Outlining Construction of Pneumatic Automobile Tire Fitted to Simple Clincher Rim 590 Fig. 310. Construction of Schrader Universal Tire Valve . . . 600 Fig. 311. Forms of Quick Detachable Rims which Permit Easy Re- moval of Pneumatic Tires 602 Fig. 312. Showing Various Raised Treads Used on Pneumatic Tire Cas- ings 004 Fig. 313. How Outer Casing Treads May Be Formed to Secure Greater Tractive Effort than Obtained from Smooth Treads and Prevent Side Slipping 606 Fig. 314. Supplementary Treads and Anti-Skidding Attachments De- signed to Use in Connection with Smooth-Tread Ca-inirs . . 608 Fig. 315. Methods of Applying Weed Chains to Tire without Jacking Up Wheel .... 600 Fig. 316. Quick Detachable Rim of the Demountable Form ... 611 30 List of Illustrations PAGE Fig. 317. Examples of Standard Demountable Rims for Conventional Types of Casings 612 Fig. 318. Cushion Tires which Provide More Resiliency than Solid Rub- ber Types but are Not Equal to the Pneumatic Forms . . . 614 Fig. 319. Novel Forms of Cushion Tires. A Cairns Detachable Seg- ment Construction. B Combination Form Comprising Heavy Tread and Inflatable Inner Tube 615 Fig. 320. Outlining Construction and Methods of Fastening Solid Rub- ber Tires to Wheels 617 Fig. 321. Twin Type Solid Tires for Heavy Motor Trucks and Meth- ods of Holding Members in Place on Wheels 618 Fig. 322. Hartford Detachable Twin Solid Tire Construction . . 619 Fig. 323. Spare Parts and Necessary Repair Equipment for Automo- biles Using Pneumatic Tires 620 Fig. 324. Forms of Tire Irons Used in Removing and Repairing Clincher Shoes 621 Fig. 325. Small Repair Kit Containing Necessary Tools and Supplies for Emergency Repairs 622 Fig. 326. Tools Found Useful when Repairing Inner Tubes . . . 623 Fig. 327. Portable Vulcanizer Outfit for Filling Cuts in Outer Casings of Patching Inner Tubes 623 Fig. 328. Acid-Cure Vulcanizing Outfit 624 Fig. 329. Special Appliance for Loosening Clincher Shoes from Rim of Wheel 625 Fig. 330. Tools for Removing Fisk " Bolted On " Casings and Method of Using Them 627 Fig. 331. Adjustable Iron for Loosening Clincher Casings that Have Stuck to Rims 628 Fig. 332. Sectional View of Pneumatic Tire Showing Some Conditions which Cause Failure 632 Fig. 333. Temporary Casing Repairs Possible when'Small Blow-out or Large Puncture Occurs on the Road 634 Fig. 334. Methods of Using Small Electric or Vapor Vulcanizers on Tube and Casing Work, a Very Convenient Method of Effecting Permanent Repairs 636 Fig. 335. How Inner Tubes May Be Pinched and Ruptured if Outer Cas- ing is Replaced Carelessly or if Tire Lugs are Not Properly Placed 637 Fig. 335a. Sectional View Showing Construction of Triple Spoke Rudge Whitworth Detachable Wire Wheel 639 Fig. 336b. Principal Types of Anti-Friction Bearings that Have Been Used in Automobile \Vork 640 Fig. 335c. Two Types of the Hyatt Flexible Roller Bearings . . 643 List of Illustrations 31 PAGE Fig. 335d. Front Wheel of Heavy Truck Mounted on Double Row Bearings . 644 Fig. 335e. Sectional View of Mais Motor Truck Power Plant with Crankshaft Mounted on Ball Bearings 645 CHAPTER XI Fig. 336. Simple Ignition Starting System Using Acetylene Gas and Hand-Operated Distribution Valve on Dash 649 Fig. 337. Ignition Starting System in which a Hand-Operated Pump Forces Mixture to Cylinders 650 Fig. 338. Never-Miss Starting System with Special Air Motor for Mechanical Cranking 651 Fig. 339. Janney-Steinmetz Compressed Air Starting System . . 652 Fig. 340. Parts of Air Starting Group Supplied on Chalmers Cars. A Pressure Supply Valve. B Compressed Gas Tank. C Dash Start- ing Button. D Mechanical Distributor. E Cylinder Check Valves. F Gas Shut-off. G Pressure Gauge on Dash. H and I Air Connection for Tire Inflation 653 Fig. 341. Motor Generator Employed in Starting Cadillac Motor also Furnishes Current for Ignition and Lighting 655 Fig. 341a. Diagram Defining Principal Types of Electric Motor Start- ing Systems 656 Fig. 341b. Practical Application of One-Unit Starting System to Motors of Conventional Design . . . 658 Fig. 341c. One-Unit Starting System in which Combination Motor- Generator Replaces Engine Flywheel 659 Fig. 341d. Practical Application of Two-Unit System Showing Relation of the Various Parts to the Power Plant 661 Fig. 341e. Wiring Diagram of Two Unit Electric Starting and Five- Lamp-Lighting System 662 Fig. 341f. Sectional View of Typical Starting Motor Showing Reduction Gearing, Clutch, and Sliding Gear to Engage the Flywheel . . 664 Fig. 341g. Sectional Views of Typical Generators Used in Connection with Electric Starting and Lighting Systems 665 Fig. 341h. Defining Construction of Overrunning Clutch of the Pawl and Ratchet Type with Automatic Throwout 666 Fig. 342. Gas Generators and Lamps Used in Connection with Acetylene Headlight Installation 670 Fig. 343. Special Storage Battery Employed to Furnish Lighting Cur- rent 672 Fig. 344. Side and Tail Lamps Using Electric Bulbs for Illumination. A Kerosene Side Lamp with Tungsten Lamp in Corner. B Pillar 32 List of Illustrations PAGE Lamp for Limousine Bodies Uses Electric Lamp Exclusively. C Small Electric Tail Lamp 673 Fig. 345. A Side Lamps Designed to Use only Electric Bulbs. B Methods of Combining Kerosene Burner and Tungsten Bulb in Side Lamps . 674 Fig. 346. Gray & Davis Combined Electric Tail Lamp and License Plate Holder, a Device of Marked Utility 675 Fig. 347. Incandescent Bulbs and Sockets Used in Motor Car Lamps 676 Fig. 348. Convenient Electric Fixtures that May Be Included in Equip- ment of Cars Using Electric Lighting Systems .... 677 Fig. 349. Sectional View of Gray & Davis Electric Headlight Showing Method of Focusing Bulb by Accessible Adjusting Screw . . 678 Fig. 350. Combination Headlight Fitted with Both Gas Burner and Electric Bulb. A Position of Bulb with Gas Flame in Use. B Bulb Furnishing Light ' . . 679 Fig. 351. Wiring Diagram. Showing Connections of Simple Three-Lamp Electric Lighting System . 680 Fig. 352. Complete Six-Lamp, Three-Circuit Electric Lighting System with Mechanical and Chemical Current Producers . . . . 682 Fig. 353. Conventional Wind Shield Forms 683 Fig. 354. Methods of Promoting Easy Riding of Automobiles Supplied with Inadequate Springs 685 Fig. 355. Efficient Shock Absorbers that Improve Spring Action on Rough Roads. A Truffault-Hartford with Friction Pad. B Con- necticut Device Moves Cam Against Spring Resistance . . 686 Fig. 356. Forms of Motor Car Alarms that Give Satisfactory Service. A Combined Klaxon Signal and Bulb Horn. B and C Exhaust Whistles. D Electrically Operated Signal 687 Fig. 357. Speedometers Useful in Indicating Speed and Mileage . 688 Fig. 358. Sectional View of Speedometer which Depends on Centrifugal Force Stored in Governor Weights to Actuate Indicating Needle 689 Fig. 359. Tool Roll Suitable for Making All Ordinary Repairs on Auto- mobile Mechanism 692 Fig. 360. Useful Tools that May Be Furnished to Supplement Contents of Tool Rolls or Ordinary Small Tool Outfits 694 Fig. 361. Group of Supplies that Will'Be Found Useful when Touring or in Maintaining Motor Cars ........ 697 Fig. 362. Leading Types of Car Raising Jacks 701 Fig. 363. Some Conventional Methods of Storing Supplies and Equip- ment 703 Fig. 364. How Two Leading Motor Car Manufacturers Make Provision for Carrying Spare Tires and Other Supplies 704 List of Illustrations 33 PAGE Fig. 365. Side Elevation and Plan View of Modern Motor Car Showing Disposition of Various Articles of Equipment without Hampering Passengers or Reducing Carrying Capacity 705 Fig. 365a. Showing Method of Utilizing the Kemco Combined Fan and Dynamo 706 CHAPTER XII Fig. 366. Parts of Motor Control System of Peerless Car. Spark Ad- vance Regulated by Small Hand Lever. Gas Supply Controlled by Automatic Engine Governor, Accelerator Pedal or Throttle Lever on Steering Wheel 710 Fig. 367. Position of Spark and Throttle Control Levers on Cadillac Car to Obtain Various Car Speeds with Gearing in Direct Drive . 714 Fig. 368. Control System of Carter Car, which Employs Friction Trans- mission 716 Fig. 369. Simple Speed -Regulation Method on Maxwell Cars Furnished with Planetary Gearsets 718 Fig. 369A. Outlining the Distinctive Control System of Ford Model " T " Automobile, which Employs Two Speed and Reverse Planetary Gearing. Location of Spark and Throttle Levers Clearly Shown in Inset 720 Fig. 370. Selective Change-Speed System of Liberty-Brush Light Runa- bout 722 Fig. 371. Side Control Levers and Pedals of Fierce-Arrow Sliding-Gear Cars 723 Fig. 372. Complete Control System of Buick Automobiles Showing En- gine Regulating Levers on Steering Wheel, Enclosed Hand Levers and Foot Control of Clutch and Running Brake .... 725 Fig. 373. Change-Speed Gates for Three- and Four-Speed Selective Trans- missions 726 Fig. 374. Control System with Single Centrally Located Gear Shift Lever and Steering Wheel on Left Side 727 (.'hart Showing Action of Selective Sliding Gearset (Plate) . . . 728 Fig. 375. Speed-Change Levers of Knox Cars 729 Fijr. 376. Complete Control Group of Mitchell Motor Cars . . . 730 Fig. 377. Center Control Levers of Jackson Cars and Pedals for Clutch Running Brake, Accelerator and Muffler Cut-out Operation . . 731 Fig. 378. Comprehensive Lubrication Chart Furnished by Manufactur- ers of Thomas Automobiles for Guidance of Owners Insures Ade- quate Lubrication of All Essential Parts of the Mechanism at Regular Periods (Plate) 733-734 Fig. 379. Two Methods of Obtaining Gasoline from Container to Prime Cylinders and Facilitate Motor Starting in Cold Weather . . 739 34 List of Illustrations Fig. 380. Special Cover to Protect Radiator During Cold Weather and Prevent Freezing Cooling Water. A Slots Open for Air Passage While Car is Used. B Radiator Completely Protected when En- gine is Stopped. Cover Retains Heat and Makes for Easy Re- starting . . 740 Fig. 380a. How the Change Speed Buttons are Located on the Steering Post of Cars Utilizing the Vulcan Electric Gearshaft ... 743 CHAPTER XIII Chart Showing Common Troubles Causing Defective Operation of Unit Power Plant (Plate) 757-758 CHAPTER XV Fig. 381. Diagram Illustrating How Current Pressure Causes Elec- tricity to Flow by Comparing It to Flow of Water from One Tank to Another 773 Fig. 382. Typical Simple Battery Ignition Group for One Cylinder Motor Using Four Terminal Induction Coil 700 Fig. 383. Some Simple Experiments to Demonstrate Various Magnetic Phenomena and Clearly Outline Effects of Magnetism and Various Forms of Magnets 778 Fig. 384. Elementary Form of Magneto Showing Principal Parts Simpli- fied to Make Method of Current Generation Clear , 782 Fig. 385. Showing How Strength of Magnetic Influence and of the Cur- rents Induced in the Windings of the Armature Vary With the Rapidity of Changes of Flow of Magnetism 784 Fig. 386. Diagrams Explaining Action of Low Tension Transformer Coil and True High Tension Magneto Ignition System . . . 787 GENERAL INTRODUCTION THE modern motor car has reached that period in its development where one can safely say that it has become perfected to such an ex- tent that further improvements must be in matters of detail only and not in alterations of essential components. It has been so widely adopted and is used in so many industrial applications that even the most conservative must admit the automobile has ceased to be an ex- periment and it is a reliable method of transportation that has dem- onstrated its worth conclusively. It is said that there are over 800,000 motor vehicles in use in the leading countries of the world, and the yearly output of the world's manufactures is approximated at about 300,000 cars per annum. Of this number over 500,000 power-propelled vehicles are used in the United States, and the yearly output of domestic producers is esti- matpd at 190,000 automobiles. The enormous demand existing for this practical conveyance has impelled the manufacture of well-devel- oped types of motor cars which can be sold at very moderate prices because they are produced in large numbers. This has resulted in a wide increase in the number of motorists and many who formerly could not afford the higher priced automobiles have become motor car operators because they can maintain the moderate priced cars at present obtainable without too great expense. Obviously, it is not difficult to acquire a knowledge of the princi- ples of operation or the mechanism .of the conventional motor car if one has had mechanical training or a practical knowledge of automo- bile construction, and it is patent that many motorists who are driv- ing their own cars have but a vague understanding of the principles of operation of the mechanism which comprises the up-to-date auto- mobile. The ranks of motorists might be augmented by many who have the means to purchase but who believe that the maintenance cost would exceed that of a horse-drawn conveyance of equal capacity, and the natural impression which prevails that only those well versed 35 36 General Introduction mechanically can operate motor cars successfully can be dispelled only by a better understanding of motor car construction. When one takes cognizance of the many vehicles successfully operated by compara- tively inexperienced persons it is apparent that operating is not diffi- cult, but it is the repairing and maintenance costs that deter many from owning motor cars. There has been no lack of instruction books or elementary treatise dealing with motor vehicle construction, maintenance or operation, but in these, for the most part, a common error has been made of assuming that the reader had more or less knowledge of mechanics. It is evident that any work which presupposes a certain amount of train- ing on the part of the reader cannot be successfully employed in teach- ing the rudiments of any science. At the other hand, pamphlets which are too elementary in character cannot convey a practical work- ing knowledge because so much is left for the motorist to learn after he has grasped the main principles underlying the design. Many business or professional men do not possess even an elementary knowl- edge of mechanical principles, and as this class forms the largest proportion of the motoring element, in defining the basic principles of an automobile, it is necessary to use simple exposition that often- times appears to be elementary to the student or engineer well versed in the subject under discussion. Many of the works on automobile construction which have been exceptionally valuable in the past have a materially lessened value because much of the matter contained therein is out of date and not applicable to the vehicles of the present day. In the present work the writer will endeavor to define the essential elements of the modern gasoline motor car, and after explaining the basic principles upon which the successful use depends, it is proposed to describe actual forms and typical mechanisms so that their practical application and the relation the various parts bear to each other can be easily under- stood. It is obvious that familiarity with the machinery of an auto- mobile will enable the operator to give intelligent attention which will insure the longest life and minimum operating expense. It is believed that a systematic and logical arrangement of the subject will enable the reader to gain an understanding of the func- tions of each part and the typical groups of mechanism illustrated General Introduction 37 and described should make for a better understanding of the various parts as they actually are in the leading automobiles. While it has been the practice in works of this character to include a general expo- sition of all types of self-propelled conveyances, including gasoline, strain, and electric automobiles, in the present instance, matter re- lating to the steam or electric motor car will not be given. The writer will discuss only those automobiles in which the gasoline engine or hydro-Carbon motor is utilized as a prime mover. The gasoline car is now used almost universally, and the steam vehicle or conveyance propelled by electric power has been practically relegated to the background. The gasoline car has such obvious advantages and is so economical to maintain that when a proper analy- sis of its good features is made, the reason for its popularity will be apparent. Among many of the advantages of the gasoline car may be mentioned first the large range of choice because of the number of types available on the market. Second the capability of running long distances without replenishing supplies. Third wide dissemi- nation of knowledge regarding its construction. Fourth no gauges to watch and practically automatic operation. Disadvantages some- times cited are an occasional unpleasant exhaust, the necessity for physical starting of the engine (at the present time largely eliminated by self-starting mechanisms), and shifting change speed gearing when road conditions or gradients demand maximum engine power. The steam car still has a number of staunch adherents because it possesses important advantages in that it has a good range of power which can be easily controlled, it is quiet in action, has freedom from vibration and simple means for control and easy restarting after a temporary stop. Some of the factors which militate against its use are a limited number of makes to select from, attention and time required to get the vehicle started after a stop of some moment, close attention required to steam, air, water, and other indicators, and on cold or damp days a visible exhaust due to the condensation of the uscil steam discharged from the engine. The electric car has many good features, and it is widely used for both pleasure and business purposes wherever proper charging facili- ties are available. It is quiet, clean, easily started and controlled, runs with no appreciable vibration, and has very simple and efficient gear- 38 General Introduction ing. The disadvantages, however, counterbalance the good points. Such vehicles are expensive to operate, owing to the great weight to be driven. Their touring radius is limited, the average being from twenty to fifty miles per charge of batteries. Other factors are the great weight to horse power ratio due to the use of storage batteries; the time taken to recharge; the liability of batteries to injury, a high initial and maintenance cost and slow speed. It is apparent that its chief field of activity would be in towns or cities, delivering merchandise, making professional or social calls, attending theaters, shopping, and other strictly urban work. Obviously, it cannot be used for touring purposes, but where cost is not an all-important ele- ment one will find the electric automobile entirely suitable and prac- tical for all town work. The writer believes that neither the steam nor electric automobile is of sufficient moment at the present time, when compared to the num- ber of gasoline automobiles in use, to warrant an extended discussion of their construction or operation. In the present volume the space which in contemporary works is usually devoted to these types will be utilized in a practical discussion of items which are usually neg- lected, such as gas engine operation, maintenance and repair; hints relating to tire restoration or manipulation and an exposition of the latest and most suitable accessories which conduce to greater safety or comfort while motoring. The omission of the historical matter which usually prefaces a work of this character may be criticized as well as the elimination of many machine details that are commonly presented chiefly because of their value in showing progress made. As the science of automo- bile engineering has reached that point where radical departures from the conventional or standard construction are not considered with favor, it is safe to assume that the era of standardization and stability of design is at hand. Many changes have been made in the past in basic design of vehicles or their components, and many parts formerly thought essential can be dispensed with. As an example of the dis- carding of designs which gave promise of being permanent, one may mention the practical elimination of the high-wheeled or buggy-type automobile, which are now almost entirely off the market. One-, two-, and three-cylinder four-cycle engines and those of the General Introduction 39 compound form or having horizontal cylinders have been displaced by the modern four and six vertical cylinder forms, the former being used even in the cheapest types which formerly utilized one or two cylinder power plants. Simple air-cooling systems are seldom used, and angle iron or wood frames which were supplied on many pleas- ure cars are now used solely on heavy commercial vehicles and pressed steel frames are now almost universally used in pleasure cars. Plain bearings, used in the past in gear sets and axles, have been replaced by anti-friction members. Lever, tiller or rack and pinion steering gears are seldom used now, irreversible wheel types are employed on nearly all classes of cars except some electric runabouts. The single chain drive is seldom seen, while the double chain system of power transmission which had wide application in pleasure cars has been succeeded by more efficient driving systems and is used only in heavy commercial car work by modern engineers. Low tension ignition and the use of batteries for electric current production are found only on old type cars. All modern vehicles in- clude mechanical generators of electricity such as the magneto, or dynamo. Two-cycle engines are not widely used except in marine ap- plications. Short stroke high-speed motors have been replaced by the more efficient and enduring modern moderate speed forms. Expand- ing band clutcrhes which had a number of advocates in the past are seldom used at the present time. But few makers use planetary or individual clutch transmissions, and two speed gearsets are seldom seen except when an epicyclic change speed gear is fitted. ' The progressive sliding gear type is passe, and the friction trans- missions which were formerly employed in many forms are now util- ized only in the simplest design on a few cars. It was formerly con- sidered good practice to use engines fitted with automatic speed gov- ernors as automobile power plants, but governed engines are now found mainly on motor trucks. Wick, surface, drip, bubbling, film or generator valve type carburetors or vaporizers have been entirely replaced by the float feed spraying type. Among some of the other features of construction which are in decline ma\ be mentioned tubu- lar front axles, semi-elliptic rear springs or long side springs and driving axles without torque or radius members. On the other hand,, during the past year there have been a number 40 General Introduction of innovations which merit detailed description because they are found on many automobiles of late models. Other works dealing with auto- mobile construction published in the past, make no reference to these improvements owing to their recent development. Among these may be mentioned torpedo and other symmetrical body forms designed to overcome air resistance ; sleeve valve motors, a general adoption of the selective sliding gearset in the three and four speed forms, the adop- tion of shaft and bevel gear drive on even the heaviest pleasure vehi- cles, the increasing tendency to favor worm gear power transmission, the universal application of magneto ignition and development of electric lighting systems. There is also more consideration of left hand control, growing use of unit power plants, wider application of block motors and two bear- ing crank shafts, and a better appreciation of the advantages of the underslung chassis. The I-beam section front axle is almost univer- sally used, and there is marked improvement in multiple disc clutches, wider application of practical self-starters, and more general adoption of ball and roller bearings at all points. The use of long stroke motors, offset cylinders and automatic lubrication systems make for pronounced increase in automobile efficiency. There is also an aug- menting tendency to place change speed gearing on the rear axle, toward the use of three-quarter springs for rear suspension, supplying larger wheels and tires as well as quick detachable wheels and rims. Some of the foreign tendencies which may influence domestic design are a return to wire wheels by some of the leading European engi- neers; the application of silent chains for valve operation, in change speed gearing and even final drive and use of front wheel brakes. In addition to these final improvements may be added a better realization of the advantages of alloy steels, a universal tendency to weight reduction, and increase of power to weight ratio. The floating rear axle has almost entirely displaced the simpler form and marked improvement is noticed in carburetor construction owing to changes in grade of fuel now supplied which impelled the development of multiple jet and compensating vaporizer forms. Many novel and practical accessories have also been developed. In order to make this work wide in scope, not only will principles of construction and operation be discussed comprehensively, but many General Introduction 41 examples from contemporary foreign and domestic practice will be given to amplify the subject and increase the reader's opportunity for the acquirement of a practical motoring education. The illustrations have been carefully prepared, and for the most part the cuts detailing construction of the various components are reproduced or adapted from actual working drawings and thus are true outline representa- tions of the objects described. As previously stated, it is believed that a concentration of effort in treating exclusively of vehicles propelled by internal combustion motors will make this treatise one of more practical value to the majority of motorists than any heretofore published. The repair hints and suggestions given for maintenance and equipment are based on a wide practical experience which dates since the inception of the industry as a designer, repairer, and operator of motor vehicles, and should be of exceptional value to those who have not had an opportunity to become familiar with automobiles but who can apply the experience of others to good.advantage. THE AUTHOR. THE MODERN GASOLINE AUTOMOBILE CHAPTER I Defining Trend of Modern Practice Explaining Important Components of the Motor Car and Considering Functions of Each Group of Mechanism. DURING the past decade great progress has been made in all branches of engineering and science. This is especially true in me- chanics, and one of the most notable achievements has been the advancement of the self-propelled vehicle from a crude and unsatis- factory construction to one of great refinement and practicability. In ten years the growth of the automobile industry stands unparalleled in the industrial history of the world. One familiar with the im- provement of the motor conveyance during that time and who remem- bers the early types marvels at the refinement of detail and the changes in design which exist in the vehicles of the present day. The modern gasoline automobile fills every need as it is comparatively light, powerful enough for all road conditions, easily controlled and capable of running for thousands of miles without adjustment of the mechanism. It surpasses the powerful locomotive in speed and relia- bility, and has a radius of travel greater than any other conveyance. There are numerous standard principles upon which motor-car construction is based, and some of these differ from each other radi- cally, both in theory and practice. Many constructions, if looked at from a purely academic point of view, will appear to possess advan- tages which cannot be questioned, though on further consideration a car of apparently inferior design which does not have the same method of accomplishing a like object may be a better seller and a more popular car among motorists. The tendency of the motor-car designer of the present day is toward simplicity and increasing efficiency of the mechanism. There 43 44 The Modern Gasoline Automobile are many rules of practice leading to this end generally known to engineers, though not accepted by all as the best methods of construc- tion for motor vehicles. It is the writer's purpose to review all the types of the various automobile components that have merit, and the qualities of each design will be given as stated by those favoring it. This is not intended as a criticism, but to enable the motorist not informed regarding details of motor-car building to make intelli- gent comparison with other forms. Within the last few years the design of automobiles has been con- siderably changed, and the difficulties that previously retarded devel- opment have been for the most part eliminated by modern automobile engineers. This gradual modification of the automobile from a crude mechanism to a practical product has been attained without radical changes that many confidently forecasted at the inception of the in- dustry. The essential elements of the motor car of to-day remain practically the same as far as basic principles of design are concerned, as those which formed the basis of the first motor car. Only the details have been changed and the forms which have resulted from the gradual process of evolution show a steady tendency toward uni- formity of design. Important Components of Modern Motor Cars. In this era of progress, one would hesitate to assert that the motor car had been perfected or that it had reached a finality in design, though the expe- rience of the last few years would justify one in assuming that the principles of construction now applied so successfully may reasonably be considered permanent. The elements which have been proven essential to insure successful operation of all self-propelled convey- ances may be easily defined as follows : First: The endeavor of modern constructors is to make all oper- ating parts of such material, size, and strength, that the severe strains imposed by the rough nature of the average road surface will be re- sisted adequately and to secure endurance and serviceability under all possible conditions of operation. Second: The mechanism should be as simple as it is possible to make it, as this promotes ease of repairing, facility in handling, and lessens the liability of trouble by reducing complications. The parts should be in proper proportion and arranged in such a manner rela- The Modern Gasoline Automobile 45 tive to each other that one may be removed or replaced without dis- turbing other correlated appliances. Third: The power furnished by the gasoline motor carried in the frame must be transmitted to the traction wheels or to the revolving shafts to which they are fastened with as little friction and power loss as is possible. Fourth: The two driven wheels (preferably the rear ones) must be connected to some form of compensating or balance gear which enables each wheel to revolve independently of the other at times and at different velocities, because in turning corners the outer wheel describes a larger arc and consequently a longer path than the inner member. The differential gear was one of the most important ele- ments which made for the successful development of the auto- mobile. Fifth : The steering should be done by the two front wfreels which are carried at the ends of a yoke axle which is securely fastened to the chassis frame by means of the springs. The wheels are carried on steering knuckles which must be arranged to assume different angles when the vehicle is turning corners or deviates from a straight path in order to secure positive steering. Sixth: Springs must be provided, which will have sufficient strength and elasticity to neutralize vibration and allow for uneven- ness of the road surface by their yielding qualities and thus reduce body movement. In order to relieve the machinery, running gear and passengers of the inevitable vibration which obtains at even moderate speed on ordinary roads the wheels should be provided with very resilient tires, preferably of the pneumatic or inflated forms for pleasure cars, and cushion or solid rubber on the heavier and slower moving motor trucks. Seventh: The gas supply to the motor, the ignition of the charge, and the continuation of the engine cycle of operations should be auto- matic and require no attention from the operator after the motor is once started. To secure continued operation, mechanical means must be provided for constant lubrication of all moving parts. All com- ponents which have movement relative to other parts should move with as little power loss by friction as possible, in order to conserve the available motor energy for tractive purposes. Anti-friction bear- 46 The Modern Gasoline Automobile ings of the ball or roller type should be employed on all rotating shafts in the power plant, transmission system, and in the wheels to save power. Eighth: The center of gravity must be carried relatively low, which involves placing the body as close to the ground as practical considerations will permit. The wheel base, which is the distance between front and rear wheel centers, should be long, in order to secure the best result in tractive effort, steering, and comfortable riding. The power plant and other essential mechanism should be carried on a frame which will be supported in such a manner that road shocks will not be transmitted to them and so coupled together that no frame distortion will produce disalignment of the driving shafts. Ninth: The control elements must be designed with a view to easy handling. This means that the steering gear should be irre- versible i. e., the hand wheel should not be affected by side movement of the front wheels, thus relieving the driver's arms of all undue strain while driving. Motor regulation should be by levers placed convenient to the driver's hands or feet, and gear shifting should be accomplished without difficulty. Powerful brakes must be employed to insure positive check of vehicle motion whenever it is desired to bring the conveyance to a stop. It is evident that the levers through which the brakes are operated should be so proportioned that a mini- mum of effort on the part of the operator will serve to check the vehicle immediately. Division of Motor-Car Mechanism in Groups. In ord^r to deal sys- tematically with the subject of motor-car construction, one may divide the essential mechanism into groups and treat each of these assemblies in detail. In order to understand the functions of the various parts, views of typical pleasure and commercial car chassis, with all components clearly indicated are presented in Figs. 1 to 7. These show conventional arrangements of parts in vehicles which are adapted to a wide range or work. Of the many elements comprising the automobile, the source of power is the most important. Then comes the method of power transmission, and last the various chassis parts which have to do with suspension, control, etc. By referring to illustrations, which show the construction of typi- LJ \uVv boft Spring Clips 70s C Rear Hub Exhc Muffler Front UniuersalJoii Brake Rod Rocker Shaft Rear Universal Joint Foot Brake Rod /Emergency fferentialandBeuef Hanger Spring riuingGear Case \ ^J Rear Spring S ^ Brake Drum FiaiiieSids Membe ChangeSpeed I Step Hanger Traction Member Semi-EllipticJSprinq inq Shackle ' Steering Whee/i Steering Column Change Speed Gear Lev Emergency Brake Le front Universal Joint Frame Side Step Hanger Rearllniuersal JointSprmg Hanger Driving Shaft Fig. 1. -Plan View and Side Elevation of Pleasure-Car Chassis Propelled by F( Each Other Flywheel Radiator Exhaust Manifold Cranhcase Breather Carburetor p iJM : Cylinder Gasoline Motor, Showing Important Components and Their Relation to : ;the Assembly. " !*<>>>>, WlKO The Modern Gasoline Automobile 47 cal gasoline car chassis so clearly, the functions of the various parts and their relation may be easily understood. The basis of any con- veyance, whether animal drawn or power propelled, is a running gear. This consists of a frame supported on springs which rest on the axles, which in turn carry the wheels on which the whele assembly can roll over the ground. In the horse-drawn carriage where there is no necessity for a heavy or strong supporting frame, because of the light weight of the body it is possible to attach the springs directly to the sills on which the body rests. In a motor vehicle, however, the frame is usually separate from the carriage work, because it is often necessary to remove the body to gain access to some portion of the mechanism which may need attention. The frame of an automobile must be strong, because the engine and parts of the transmission system are installed thereon, and also because the speed possibilities of the auto- mobile make it necessary that the frame be of sufficient strength to resist the stresses due to car movement when driven over uneven road surfaces. These strains are not present in other forms of conveyances. The locomotive which is capable of high speed and which is very heavy, travels on a smooth track, while ordinary horse-drawn car- riages are not affected materially by the roughness of the path on which they travel because of their low speed and light weight. In the frame, or chassis group, one may include the main frame, sub- frame, steering gear, clutch and brake pedals, hand levers for varying change speed gear ratios, and applying emergency brakes; the front axle and its steering connections, the driving axle and brakes, the wheels, the tires, and the springs which form a yielding connection be- tween the axles and the frame. The power plant of a gasoline automobile is composed of a num- ber of distinct devices of which the engine proper is the most impor- tant, though all of them are necessary to insure practical operation. In order to describe power plant construction logically, it may be divided into six distinct assemblies, each of which may be resolved into the various parts of which they are composed. The most im- portant assembly is the motor; then the gas-supply system, the igni- tion apparatus, the devices used for lubrication, the system of cooling, and the muffler assembly. The power transmission mechanism is the next group of impor- 48 The Modern Gasoline Automobile tance. In this assembly one places the clutch, the gearset, the driving means, and, in most instances, the rear axle and traction members. Arrangement of Parts Varies. In the conventional car the motor is usually placed at the front end of the frame, and the various aux- iliary devices are grouped around it. This is the modern method of power plant placing, but even now there are cars constructed in which a horizontal engine is placed longitudinally in the frame par- allel with the side members. This arrangement was formerly more popular than it is at present, because it permitted a simple method of power transmission by use of single driving chain. In some cars the change speed gearing is placed in the center of the frame, or directly back of the engine, as shown at Fig. 1. In other cars it may be incorporated with the rear axle, as outlined in Fig. 2. The final drive to the rear wheels may be by means of shaft and universal joint connection, as shown at Figs. 1 and 2 ; this being the common arrange- ment on pleasure cars; or by means of a combination of shaft and chains used more often on commercial vehicles. This form of drive is shown at Figs. 4, 5, and 6. The power delivered by the motor crank shaft is transmitted to a countershaft which is placed across the frame by means of a shaft, and from each end of these countershafts the energy is delivered to the rear wheels by chain and sprocket con- nection. There are many other variations in arrangement of parts which will be described in proper sequence. The examples mentioned are given merely to show that the essential elements may be placed at various points in the frame without impairing their utility. The complete frame assembly, including power plant and exclusive of the body or other carriage work, is usually termed a " chassis." There is no marked difference between pleasure or commercial vehicle con- struction. The same essential elements are incorporated in both, though obviously the parts of a conveyance intended for industrial transportation are made much heavier because of the severer duties they perform than those employed in pleasure cars which, neverthe- less, may have much greater power. Parts of Typical Automobiles and Their Functions. A brief expla- nation of the function of each part of the gasoline car chassis de- picted at Fig. 1 will serve to afford a better understanding of the W.t.M\ U V'^%% Rof ferential and Btuel Driving Gear Atsembly Fig. 2. Plan View Depicting Important Parts of a Prominent English Pleasure C ? : Chassis in which Power is Furnished by a Six-Cylinder Internal Combustion Engine. c . The Modern Gasoline Automobile 49 construction of an automobile. The purpose of the front axle is not unlike that of a horse-drawn vehicle, but it is much different in con- struction. The wheels are installed on movable spindles, or steering knuckles, which are supported by yokes permitting one to move the wheels for steering rather than turning the entire axle on a fifth wheel, or jack-bolt arrangement, as in a horse-drawn vehicle. This axle is attached to the frame by spring members which allow a certain degree of movement without producing corresponding motion of the frame. The radiator, which is placed directly over the axle in front of the motor, is employed to hold the water used in keeping the engine cool and is an important part of the heat-radiating system. The starting handle is a crank by which the motor crank shaft is given sufficient initial movement by the operator to carry the engine parts through one or more portions of the cycle of operations, this starting the engine. The tiebar joins the arms of the steering spindles on which the wheels revolve, and insures that these will swing together and in the same direction, either to the right or left. The steering link, often called the " drag link," connects one of the steering knuckles of the front axle with the steering gear. The motor may be one of the many forms to be described and one of two distinct types. The dash is a wooden or metal partition placed back of the power plant to separate the engine from the seating compartment. It is often employed to support some of the auxiliary apparatus necessary to motor action or some of the control elements. The clutch is a device operated by a pedal, which permits the motor power to be coupled to the gearset and from thence to the driving wheels, or interrupted at the will of the operator. It is used in starting and stopping the car and whenever the change speed gears are shifted. The accelerator is a small pedal which actuates a valve on the gas- supply device to permit more explosive mixture being fed to the engine when it is desired to increase the motor speed. Its function is comparable to that of the throttle of a steam engine. The pedals are foot-operated levers; one of which releases the clutch, the other applies the running brakes. The motor control levers on the steering column are used in conjunction with the accelerator to vary the rota- tive speed of the motor and thus regulate the energy produced in 50 The Modern Gasoline Automobile proportion to the work to be performed. The emergency brake lever applies a powerful braking effect when it is desired to stop the car quickly and also when one wishes to lock the brakes if car movement is arrested on a down grade. The change speed lever operates the sliding gearing, which is utilized to produce varying ratios of velocity Steering Wheel front Wheel Water Outlet Steerjng Posf 1 ^. Emergency Brake Leuer Radiator \ fxnauat />/pe*\ s$\ /.Gear Shift Leuer Fig. 3. Side Elevation of Sheffield-Simplex Six-Cylinder Chassis; a Typical Design of English Derivation. between the engine shaft and the rear wheel. The steering wheel actu- ates the mechanism which moves the wheels to the right or left when one wishes to describe the circle, turn a corner, or otherwise deviate from a straight line. The change speed gear is one of the most important elements of the power transmission system and in connection with the clutch it is much used in operating and controlling the vehicle. The function of the frame has been previously described. The exhaust pipe is em- ployed to convey the inert gases discharged from the motor cylinders to a device known as the muffler which is designed to reduce gas pres- sure by augmenting the volume and thus diminish the noise made as it issues to the atmosphere. The driving shaft transmits power from the change speed gearset to the bevel gearing in the rear axle. A universal joint is a positive connection which permits a certain degree of movement between two shafts which must be driven at the same speed. One or the other, or both, may move in a lateral or ver- tical plane to a limited extent without interrupting the drive or cramp- Cou Foui "SpeedtSelectiue" Sliding Gearbox Intake Pipe Power PI Pad \ Flywheel ^y^ ^^ ^ ^^ JSteeringKnucMe Counter Solid Rubber Tire Steering Wheel .Coolinq Fan Solid Rubber -Tire Emergencyffrah6t Lever Brake Operating flod Main Frame Side Member l( N ,< ,, Driving Shaft \Spring HangeT\^~- -\ Geur BOX P _ ; r^ ..__ 'fO J 8ub-Fram& Drag Link Fig. 4. Plan and Side Elevation of Heavy Commercial Truck Chassis of F. Traction Wheel shaft Brake Rod 1am Shaft DnvingChain Shaft Shaft 1 : Bevel Gear ana.. - Differential Assembly.Case Countershaft Distance Rod "Dead" or Stationary hear. Axle Frame Overhang Q ft Brake Pear Wheel Brake Rod Countershaft Brake Rod Re-in forced Spoke Wood Wheel 'firing Shackle Rear-Spring Hanger Rear Spring Wide Steel Tire ; ign Design, Showing Essential Elements and their Location in the Frame. The Modern Gasoline Automobile 51 ing the moving parts. The rear construction houses the differential and driving gears, and the shafts or axles which transmit the power to the traction wheels. Brakes are used to retard, or stop, the move- ment of the wheels, and are operated by rods which transmit the force the operator applies at the brake pedal oj hand lever to the brake band. Torque members are used to maintain a definite relation between the driving gears in the axle and those in gearset, and to take the driving thrusts off the axle and the strains imposed by brak- ing and driving from the springs. The principles underlying opera- tion of each of the parts shown and the number of different forms in which they may exist, will be described more extensively in the chap- ters dealing fully with the various groups. Assembling Typical Chassis. The parts which compose the mod- ern automobile and their relation to each other can be very easily as- certained and understood by even those deficient in mechanical knowl- edge, by consulting Figs. 8 to 13, inclusive. These show the various steps in assembling a typical American car, and have been prepared by the Locomobile Company to show the ease with which their cars may be assembled, or dismantled. At Fig. 8, A is shown the bare pressed steel frame which forms the basis of practically all motor cars, before any of the other parts have been added to it. It will be seen that it consists of two side members of pressed steel, these usually being a channel section. The two side members are joined by a series of four cross pieces. The wide one at the front end serves to support the radiator and the starting crank. The two which are placed a little forward of center in the chassis are utilized to support the change speed gear case. The rear cross mem- ber is employed solely as a bracing piece, and is reinforced by two triangular gusset plates. All the frame members are securely joined together by steel rivets. It will be noticed that the front end of the frame is narrower than the rear portion. This is to permit the front wheels to assume a more abrupt angle than would be the case if the frame bars were not cambered. This permits one to maneuver the car more easily in narrow streets because it permits one to turn more briskly. At Fig. 8, B, several parts have been added to the frame. The front springs have been attached directly under the front end, and Steering .Wheel Traction Wheel Fig. 5. Plan View of Light American Motor Truck Chassis. 52 54 The Modern Gasoline Automobile the front axle has been installed and fastened to the springs by means of clips. The supporting springs at the back end as well as the front and rear shackles or hangers have also been installed. Attention is called to the method of supporting the rear ends of the rear springs Spark Advance Leue Throttle Lever Gear Shift Leuer Emergency Brake Steering Wheel Fig. 7. -Front View of Gasoline Pleasure Car Chassis with Section of Radiator Broken Away to Show Placing of Power Plant in Frame. by a through bar which passes through the two side members, serving very effectively as an additional brace. The illustration at Fig. 9, C depicts the chassis after the headlight supporting brackets, or lamp irons, the motor or complete power plant and the dash have been placed in their proper positions. The appear- Radiator Bar Frame 2r i Fig. 30h. Application of the Hoadley System Two- Wheel Drive and Steer Tractor to Heavy Low Gear. medium of a change speed gearset, which in turn delivers the power to a countershaft carried by the frame side members forward of the rear axle. The drive to the rear wheel sprockets from the counter- shaft is by roller chains. The method of control, power application, etc., is the same as in any motor truck. The application of the three-wheel tractor to the work of hauling heavy loads in a commercial manner is clearly indicated at Fig. 30/. At the top view the tractor is shown attached to a load of lumber, while at the bottom the method of detaching the tractor and sending it for another load while the trailer is being unloaded is shown. It is merely necessary to fit the trailer with a pair of supporting jacks at the forward end so that it mav be raised clear of the fifth wheel The Modern Gasoline Automobile 83 on the rear axle of the tractor. Using the tractor in this manner makes it possible to utilize one of these mechanical horses to haul various trailers, and tlnere need be no loss of time as far as the motive power is concerned while unloading the trailer. Steel Tired Trailer Fig. 30g. The Couple-Gear Four- Wheel Drive and Steer Tractor Attached to Large Coal Wagon. Other forms of tractors have been devised for hauling very heavy loads in which four driving wheels are employed to secure better traction. As a general rule the four-wheel drive tractors are of the gasoline-electric type and all four wheels combine directive and tractive functions, as the electric motor imparting power to the wheel is housed in its interior. The four wheels are mounted on steering knuckles, so they may be turned to any desired angle for steering. A tractor of this form is shown at Fig. 3Qg, and is of the Couple- Gear type. The power is generated by a four-cylinder gasoline motor which drives a dynamo, and the current from this dynamo is directed through a suitable controller to the motors in the four wheels. This system of drive is specially well adapted to moving very heavy loads, and the adaptability of the Couple-Gear tractor in hauling an ex- tremely large and heavy coal wagon is clearly depicted. A full 7hich is Buflt on Regular Motor Car Lines, but on a Miniature Scale. v>V*\ The Modern Gasoline Automobile 87 simpler or less expensive cyclecar forms will be. They cannot be built as cheaply as a certain light car that is produced in very large quan- tities in this country and which gives exceptional service. The car shown at A is the baby Pugeot and is a French design employing a four-cylinder water-cooled motor of about 10-12 H. P., a sliding gear transmission and shaft drive to a live rear axle. In all respects it follows automobile practice. The form outlined at B is an Eng- lish design known as the " Humberette." This employs a two-cylinder air- or water-cooled motor. It uses a geared transmission and also has shaft drive to a live rear axle. The form depicted at C is the Auto-Carrier's four-cylinder model and is an English design pat- terned more after the automobile than the motorcycle. As an example of the method of construction followed by the designers of miniature automobiles, the chassis of the Marlborough small car is depicted in both plan and side elevation at Fig. 30fc. As will be seen, the general design follows regular automobile prac- tice very closely, starting with the four-cylinder water-cooled block motor at the front end and the flywheel clutch, sliding gearset, and shaft drive to a live rear axle. That it is a miniature car, however, is apparent if one considers that the motor is rated at about 12 H. P. and that the tread is but 36 inches. The frame is very narrow and is arranged so the two passengers are carried tandem fashion, with the driver in the front seat. The only respect in which a chassis of this form may be considered as following motorcycle practice is in the use of wire wheels, small tires, and motorcycle type mud-guards. In all other respects it is a miniature motor car and will cost as much to build, if it is not actually more expensive in construction than the popular American runabout. The original cyclecar was designed to take the place of the motor- cycle and sidecar combination that has been very popular in Europe, even more so than in this country. This is shown at the top of Fig. 30/, is known as the "Bedelia," and a model was built by M. Bar- beau, of Paris, France, as early as 1910. This was a very small automobile driven by a motorcycle power plant. Its weight was less than 400 pounds and it had a tread of 36 inches. The wheel-base was 100 inches, and as it was very low, the passengers were carried very comfortably. It was made to accommodate two persons, the 88 The Modern Gasoline Automobile passenger being seated in front, while the driver sits over the rear axle. On the modern forms the twin-cylinder motorcycle engine of about eight H. P. is placed just behind the front axle and drives a countershaft which is crosswise of the chassis under the passenger's seat by a roller chain. Pulleys of the motorcycle type suitable to take the regular V belt are attached to the ends of the countershaft, and these impart motion to the large belt pulleys on the rear wheels by means of motorcycle belts. An ingenious clutch action is obtained by drawing the rear axle forward when it is desired to stop the car, as this makes the belt run loose and enables the motor to turn without driving the wheels. A further movement of the hand lever brings the rear axle forward far enough so the belt pulleys engage fixed brake blocks or shoes which arrest motion of the wheels. The steering is by means of a wire- spoke hand wheel which turns the whole front axle through a drum on the steering shaft and a steel cable connection through pulleys. The axle is hung at a central point in a steering head very similar to that of the bicycle. The first public appearance of the car was in a road race over a course one hundred and thirty-eight miles long, and this small vehicle surprised the public, and more so its inventor, by averaging thirty- eight miles an hour the entire distance. The same car attained a speed of fifty- five miles per hour on a track. This resulted in a large demand for these cyclecars and induced many manufacturers to enter the field. The De Cross cyclecar, which is shown at Fig. 30Z, is an Amer- ican design patterned largely after the Bedelia. The Lester is a light English design adapted for but one passenger and is a true cyclecar in all respects, as the motor is an air-cooled type and the drive to the rear wheels is by means of motorcycle belts. The first Bedelia type cars built in England were patterned very largely after the original design, but very soon the demand was for more artistic body designs and more luxury, so that at the present time many of the vehicles produced in England that are called cycle- cars are really small automobiles that sell for as high as $1,000, although they still retain the narrow tread, which is considered a feature of decided advantage, inasmuch as it permits the cyclecar to be housed in a small shed and avoids the necessity of special full-size The Modern Gasoline Automobile 89 Fig. 301. Representative Types of True Cyclecars. garage facilities. It is claimed that the 36-inch tread construction is not suitable for American roads because it will not track with other vehicles which use the standard tread of 56 inches. It is, of course, admitted that the main highways of Continental Europe and of 90 The Modern Gasoline Automobile England have exceptionally good road surfaces. In France, however, where the first cyclecars were produced, there are plenty of byways with ruts worn by traffic which, while perhaps not as bad as the majority of country roads in America, offered ample opportunity to test the practicability of the narrow-tread cyclecar. As there has been no change in the tread of the Bedelia in three or four years, and as the narrow tread has been continued by other French and English designers, it is apparent that the narrow tread gave satis- factory service. The usual width of the road ruts in America is 7 or 8 inches and they are 56 inches apart, which means that there is approximately a space of 42 inches between the wheel tracks, which should be ample to allow a vehicle of 36-inch tread to pass between them. The true cyclecar offers a number of features that will enable it to fill a distinct field that cannot be catered to by the builders of either low-priced automobiles or motorcycles. In the cyclecar there is a lack of complication in the mechanism, a low center of gravity making for stability is obtained, a streamline body construction, especially in the tandem seating arrangement, is possible which reduces wind resistance to a minimum, and owing to the lightness of the vehicle a small engine may be employed that will use very little gasoline and lubricating oil, and the small motorcycle tires that can be used will reduce tire cost materially. While at the present time there are no reliable statistics regarding the cost of maintenance in this country, if one reasons from experience with a motorcycle and sidecar combination, it is possible to arrive at the conclusion that two persons can travel over average highways at a total cost for fuel and tires of not more than two cents per mile, whereas it would cost at least three times this sum to cover the same distance with the lightest form of miniature motor car. Several designs are being pro- duced at the present time in this country that will sell at prices ranging from $350 to $450, and it would seem reasonable to assume that many people could afford to purchase a cyclecar who would not be interested in a small automobile on account of its higher initial cost and greater maintenance expense, and yet who would not favor the motorcycle or sidecar combination at the same cost on account of the superior protection and easier control of the cyclecar. The Modern Gasoline Automobile 91 92 The Modern Gasoline Automobile The chassis of a simple form of English cyclccar in which n friction-disc transmission is employed to obtain the various speed ratios, and which derives its power from a small four-cylinder motor, is clearly shown at Fig. 30m. This chassis is more on the light-car order and can be compared to the true cyclecar form at Fig. 30n, to enable the reader to make comparisons between the two methods of construction. It will be observed that the chassis construction outlined at Fig. 30n is a fourwheel motor vehicle reduced to its simplest form. The engine, which is an air-cooled motorcycle type having two cylinders set at an angle, is secured at the front end, where it will get ample cooling, and is located immediately under the torpedo-shaped gasoline tank. The wire wheels are carried by miniature steering knuckles attached to a light tubular front axle. The spring suspension at the front end is by quarter elliptic leaf springs which combine the duties of a resilient support for the frame as well as distance or radius rods for the -axle. The wood frame is extended to the rear, where it tapers to a point, and in most cycle- cars it is made of ash. The drive from the sprocket on the engine crankshaft is by a motorcycle roller chain to a larger sprocket on the countershaft. At each side of the countershaft V belt pulleys are mounted which drive the rear wheels through leather belts. In the simple form shown the clutching action is obtained by sliding the axle back to tighten the driving belt and produce forward motion, while it is pushed forward to loosen the belt and obtain a free engine action by the belt slipping over the pulleys. The simple arrange- ment shown is varied in other constructions by placing the power plants crosswise of the frame and utilizing a friction-disc transmis- sion, as shown at Fig. 30m, to obtain the varying speed ratios. In such a case the movable friction wheel will be moved back and forth on the countershaft to obtain different speed ratios, while the friction disc will be pulled out of contact with the friction wheel when it is desired to interrupt the drive to the rear wheels. It is generally believed that the tandem seating arrangement is superior on account of the lessened air resistance, and it will pro- vide greater speed than the side-by-side seating so widely used in automobile practice. The arrangement of the tandem seats is clearly The Modern Gasoline Automobile 93 1 94 The Modern Gasoline Automobile shown in two of the cyclecars at Fig. 30/, though in this country the arrangement is usually varied so the driver occupies the front seat instead of the rear one, as is the case in the Bedelia design. An ingenious arrangement to provide side-by-side seating without unduly increasing the width of the body is shown' at Fig. 30o. The seat for the passenger is placed somewhat in the rear of the driver's seat and the body can be narrower than if the seats were on the same plane. Agricultural Automobiles or Gas Tractors. During the past decade there has been important advances made in the application of Fig. 30o. Plan View of the Falcon Cyclecar Showing Staggered Arrangement of Seats. gas power to agricultural purposes, and now practically all farms of any size in the United States or Canada are tilled by plows drawn by mechanical power and the crops threshed by the same means. These large machines are really automobiles and in many respects fol- low automobile designs, especially as relates to power generation and transmission, though on a much larger scale. A few paragraphs out- lining the requirements of the ideal tractor and a consideration of several types that follow automobile practice will enable one to form an intelligent idea of the main features of a well-developed modifi- cation of the commercial type of automobile. The requirements of the ideal tractor can be summed up as fol- The Modern Gasoline Automobile 95 lows: First, it should have universal adaptability, in order to be able to accomplish all kinds of belt or drawbar work, as it is only by having a machine that is applicable to a large variety of tasks that one can justify the investment needed to purchase a practical machine. It should be capable of operating every machine on the farm that requires power. Second, it should have correct weight for the work it is to do and the proper arrangement of components. A logical distribution of weight is necessary to insure proper traction. If the machine is too heavy it will pack the soil and much power will be consumed in moving the huge mass over the ground. The factor of weight is especially noticeable when climbing grades. If the tractor is too light, it will not have adequate adhesion with the ground and much power will be lost in slipping between the driving wheels and the ground. The weight should be distributed so the greater part of it will come over the rear wheels, as in most constructions these are called upon to do the driving. Third, there should be a large contact area between the traction members and the ground in order to avoid loss of power, packing of soil, and slipping. It should be provided with change speed gearing that will provide at least two forward speeds and a reverse motion. The drive from the power plant to the rear wheels should be positive and designed so that there will be minimum loss of energy through friction in gearing. Fourth, it should be of consistent design for the work it is to do, built of the best materials that can be obtained within reasonable limits and incorporate in the construction strength without excessive weight. The entire mechanism, including the power plant, should be simple, because lack of complication is practical insurance against mechanical trouble. Fifth, it should be easy to start and the control elements should be designed so the tractor can be directed without undue expenditure of energy. The simpler the control members, the easier the avonigo farmhand will find it to handle the machine. The construction should be such that an automatic steering attachment can be used in cer- tain classes of work, such as plowing, so the engineer may tie rote part of his time to manipulating the plowshares. 96 The Modern Gasoline Automobile to f* o , The Modern Gasoline Automobile 97 Sixth, it is desirable that the engine be capable of operating on any liquid fuel, especially the cheaper and more plentiful distillates of petroleum. There are a number of tractors offered at the present day that meet all of the above requirements. The construction is good, both from an engineering and practical point of view. The machines are economical to maintain and operate, and in many cases, especially in power plant and driving mechanism design, useful lessons have been drawn from current automobile practice. It is safe to say that the tractors which more nearly incorporate the good features and ideal requirements are those which follow, in a modified form, some of the rules of practice established by automobile designers. In essen- tial elements the automobile and tractor are similar. It is merely in detail arrangement of parts that they vary. A tractor that has been well received by many farmers is built on the order of the motor truck used in cities for hauling merchan- dise. It will carry a load of three tons in the wagon bed with which it is provided and has a pulley for driving stationary machines. A drawbar is provided for pulling plows and other machines requir- ing draft. The weight of this truck is carried on four wheels, there- fore when used for plowing, ballast must be put over the driving wheels in order to provide proper traction. As the machine is spring mounted and adapted to speeds from two to fifteen miles per hour, ; can be used for a wide variety of work. Instead of using rubber res as the ordinary motor track does, the wheels are provided with 'ooden plugs to adapt the tractor to hard roads. Traction on soft round is provided by an extension rim with a number of mud lugs ttached, which is so fastened to the wheel that these automatically ip the soil when the wheels sink to a certain depth. It is also pos- ble to move a hand lever on each driving wheel which, causes a eries of sharp spikes to project beyond the periphery of the wheel increase traction when desired. A machine of this nature is shown at Fig. 30p, which clearly ntlines the general construction. As will be seen, in general form it does not differ radically from the usual typo of motor truck. A? ; is provided with a wagon bed, it will haul grain, hay, stock, coal, The Modern Gasoline Automobile The Modern Gasoline Automobile 99 lumber, milk, fruit, vegetables and other kinds of merchandise. It has suflicient tractive power to pull three 14-inch plows and a har- ro\v in ordinary stubble plowing and will complete an acre an hour. It will pull two disks, two spike harrows, two seeders, two binders, corn planters, a road grader, a train of loaded wagons, or any other machinery. It has a draft equal to ten horses. This gen- eral purpose machine, therefore, is ideal for the small or medium- si /in! farm, as it will not only haul loads of all kinds on its own body, but will do field work and serve as a portable belt-power plant when desired. Automobile Plow. A form of automobile which has been designed e-jvially for agricultural use is depicted at Fig. 3Qq. This is a self-contained automobile plow having three shares carried un- derneath the frame. The front wheels are employed for traction and are driven from sprockets on the countershaft by means of roller chains. The motor is carried at the front of the machine, and is mounted directly over the front axle. It drives a transmission gear carried on the countershaft and is controlled just the same as the regular form of automobile motors by control levers attached to the steering wheel, which regulate the motor speed by varying the time of ignition and amount of gas supplied the cylinders. A single roar wheel is carried at the back end of the frame and is adapted to be moved by steering ropes controlled by the hand wheel. This rear wheel is depended on for steering, whereas the front members are employed only for traction. It is claimed that when the plow- shares dig into the ground the traction members have sufficient ad- hesion to draw them through the most resisting soils. Other forms of tractors have received very wide application in our middle West that follow automobile construction to some ex- lent, as far as power plant location, method of power transmission, speed changing, etc., are concerned, though the large size of the driving wheels and the massive construction of the frame, power !!;uii. etc., resembles more the design of the steam road rollers \v are all familiar with, rather than having the appearance usually n Delated with the conventional automobile. CHAPTER II How Power is Generated Two- and Four-Cycle Engine Action Features of Sleeve Valve Motor Principal Engine Types Described One- and Two- Cylinder Engines Advantages of Four- and Six-Cylinder Forms Power Plant Location. IT has been previously stated that the gasoline automobile may be divided into groups and that these various assemblies all have their important work to do and that each depend, to some extent, upon the correct action of the others to insure a smooth working motor car. The most important, and the least understood, element is the power plant, and it is important that the prospective motorist familiarizes himself with the principles of gasoline engine operation in order to easily locate troubles and derangements which interfere with correct action. If the operator is familiar with the basic prin- ciples of internal combustion engine action it will not be difficult to apply this knowledge to all forms of gasoline motors used as automo- bile power plants. Forms of Engines Commonly Used. If one raises the hood at the front of a motor car, one will find a complete engine assembly very much the same as that depicted at Fig. 31, which outlines a con- ventional engine with the various auxiliary parts lettered so that one can obtain an idea of their location relative to each other. Of the external parts shown the carburetor is employed to mix the gasoline used as fuel with a certain amount of air in order to form a gas that can be ignited in the engine cylinders. This explosive mixture is supplied to the cylinders by a conductor known as the inlet pipe. The spark plugs and magneto form part of the ignition outfit. The engine shown is a four-cylinder form and operates on fhe four-cycle principle. Various forms of engines have been applied to automobile propulsion, and of the large number of different types the majority operate on the four-stroke principle, though the two- stroke types are simpler. In the latter there is an explosion in each 100 The Modern Gasoline Automobile 101 cylinder every turn of the crank shaft, while the other method pro- vides but one power impulse per cylinder every two turns of the re- volving elements. Though the four-stroke motor is more complicated in construction than the other it is the easiest to understand. All in- ternal combustion motors, usually termed " gasoline engines " because of the use of this liquid fuel, are forms of heat motors owing to the Oil Tank Spark Plugs Comoreesio Cylinder- 'ater Outlet Spark Advance Rods Flywheel Lower Half of Crankcate Upper Crankcaae Fig. 31. Typical Motor-Car Power Plant, Showing External Appearance and Location of Important Auxiliary Mechanisms. energy being produced by the rapid burning, or combustion, of a gas which expands after it is exploded and produces pressure that is transformed into mechanical power by simple mechanism. In defin- ing the principles of four-cycle motor action, one can explain the matter very clearly by comparing the effect produced by exploding -oline gas to that which obtains when one explodes gunpowder n a gun. 102 The Modern Gasoline Automobile How the Gasoline Engine Works. At Fig. 32, A, the upper view shows a section through a simple one-cylinder gasoline engine, while the lower one illustrates an old pattern muzzle loading cannon. Con- sidering first the phenomena which obtains when gunpowder is burned, one can obtain some idea of how exploded gasoline vapor may be transformed into power. In fact, the preliminary operations which have been necessary before the gun was fired, are very similar to those which preceded an explosion in the cylinder of the gasoline engine of the four-cycle type. Following first the cycle of operations necessary to fire the cannon, graphically shown at the lower portion of Fig. 32, it will be seen that a certain sequence is necessary. At A we have the loading, or charging of the mortar. The powder which is carried in bags for convenience is introduced in the muzzle and pushed back into the breech with the ramrod. After the powder has been compressed the ball is placed and tightly rammed in place on top of the powder in the explosion chamber, as shown at B. After the powder is properly compacted it is exploded by means of a lighted fuse, or percussion cap, and the cannon ball is forced out through the open end because of the pressure of gas on its underside, this having been produced by the rapid burning of the powder. The next operation is clearing the mortar of the burned gases in order to introduce a fresh charge of powder and shot. The clear- ing is automatically performed, a,s shown at D. As soon as the ball leaves the mouth of the mortar the gas which is still under high pres- sure escapes to the atmosphere. After the barrel is swabbed out, one can introduce another charge and fire the cannon again. The power to propel the shot through the air has been obtained by burning a substance which before ignition had no power to produce motion of the ball. If an equal charge of gunpowder had been placed in the open air and the shot placed upon it, one would find that if the com- bustible material were ignited, there would be very little energy produced. There would be a flash of flame, but it is doubtful that this would have sufficient energy to cause the cannon ball to leave its position. Powder compacted in the cannon barrel produced use- ful energy because pressure was confined in a chamber having rigid walls at all sides, except one, this being the side of the cannon ball nearest the explosive. The metal surrounding the explosion chambo" 1. Cylinder Filling with Gas. 2. Piston Compressing Gas. Inlet Pipe Inlet Value shown Cylinder i ' Combu,\ J. Powder Inserted 2. Powder Compressed. Fig. 32. Diagram Comparing Action of Four-Cycle Engine with that of M Enabling the Reader to Compr< iding Cannon in Order to Simplify Explanation of Cycle of Operations, thus s Fundamental Principle Clearly. >wQ\QXu '. The Modern Gasoline Automobile 103 had sufficient strength to resist the high gas pressure, but the ball which was movable was driven out because its weight was not suf- ficient to resist the force applied to it by the exploded powder. It is evident that burning powder in the air will produce a certain amount of energy, but as the explosion takes place in the open there will be nothing to restrain the pressure, and just as soon as the powder is lighted any energy evolved is dissipated into the atmosphere instead of the force being directed against yielding members. The ball is forced out of the gun barrel, not only by the gas pressure which re- sults as soon as the powder is exploded, but also by the expansion of the gases generated by combustion which tends to accelerate its motion toward the end of the barrel. As the shot moves toward the end and the gas occupies more space its pressure becomes less, and when the ball leaves the mouth of the motor there is very little power remain- ing in the moving gas. There is sufficient pressure, however, so that the gas rushes out of the interior and the barrel is thus cleared of inert products which have no useful force. The action of a modern repeating rifle is somewhat different than that of a muzzle loader, because the powder is already compressed in metal shells which are introduced at the breech of the gun instead of at the muzzle. The number of shells are carried in a magazine, and after one of these explodes the recoil due to the explosion of the gas supplies another charged shell to the breech and the operation of firing the gun may be repeated as long as the supply of ammunition in the magazine lasts. The modern gasoline engine follows the action of both the old type muzzle loader and the more modern form in which the shell is introduced at the breech. Eeferring again to sketches at top of Fig. 32, we can compare the action of a simple four-stroke engine with that of a cannon which is illustrated below them. Th principal elements of a gas engine are not difficult to understand and their functions are easily defined. In place of the barrel of the gun one has a smoothly machined cylinder in which a small cylindrical or barrel-shaped element fitting the bore closely may be likened to a bullet or cannon ball. It differs in this important respect, however, as while the shot is discharged from the mouth of the cannon the piston member sliding inside of the main cylinder cannot leave it. 104 The Modern Gasoline Automobile as its movements back and forth from the open to the closed end and back again are limited by simple mechanical connection or linkage which comprises crank and connection rod. It is by this means that the reciprocating movement of the piston is transformed into a rotary motion of the crank shaft. The fly wheel is a heavy member attached to the crank shaft which has energy stored in its rim as the member revolves, and the momentum of this revolving mass tends to equalize the intermittent pushes on the piston head produced by the explosion of the gas in the cylinder. If some explosive is placed in the chamber formed by the piston and closed end of the cylinder and exploded, the piston would be the only part that would yield to the pressure which would pro- duce a downward movement. As this is forced down the crank shaft is turned by the connecting rod, and as this part is hinged at both ends it is free to oscillate as the crank turns, and thus the piston may slide back and forth while the crank shaft is rotating or describing a curvilinear path. In addition to the simple elements described it is evident that a gasoline engine must have other parts. The most important of these are the valves, of which there are two to each cylinder. One closes the passage connecting to the gas supply and opens during one stroke of the piston in order to let the explosive gas into the combustion chamber. The other member, or exhaust valve, serves as a cover for the opening through which the burned gases can leave the cylinder after their work is done. The spark plug is a simple device which may be compared to the fuse or percussion cap of the cannon. It permits one to produce an electric spark in the cylinder when the piston is at the best point to utilize the pressure which obtains when the compressed gas is fired. The valves are open one at a time, the inlet valve being lifted from its seat while the cylinder is filling and the exhaust valve is opened when the cylinder is being cleared. They are normally kept seated by means of compression springs. In the simple motor shown at Fig. 32, the exhaust valve is operated by means of a pivoted bell crank rocked by a cam which turns at half the speed of the crank shaft. The inlet valve operates automatically, as will be explained in proper sequence. Considering the view shown at Fig. 32, A, the first necessary The Modern Gasoline Automobile 105 operation is charging the cylinder with explosive material. The piston is at the top of. its stroke and it moves toward the open end of the cylinder. The engine works as a pump, and the piston draws in a charge of combustible gas through the open intake valve, which is in connection with the vaporizer which furnishes the gas. An auto- matic valve opens because of a light vacuum or suction existing when the piston has traveled down a certain portion of its stroke, and then the outside air pressure is greater than that in the cylinder. The external air pressure is greater than the tension of the spring which tends to keep the valve closed and the member is therefore drawn from its seat by the piston. At the end of the intake stroke, which is shown at Fig. 32, A, and after the cylinder has filled with gas the pressure inside and outside is the same and the valve spring closes the intake valve. As the exhaust valve spring is very strong this member has not been lifted from its seat by the difference in pres- sure. The exhaust valve is opened by mechanical means solely and only when operated by the cam and push-rod mechanism. The condition in the cylinder and the gas engine after the piston has reached the bottom of its stroke is very much the same as that which obtains in a gun of the muzzle-loading type after the explo- sive charge has been introduced. We have learned that, to obtain power from gunpowder, it was necessary to compact it firmly in the combustion chamber of the gun. The gasoline gas which has been taken into the engine cylinder must also be compressed before it is ignited, in order to obtain power. It is compacted into one- third or one-quarter of its former volume, and whereas its pressure is about fifteen pounds per square inch before it is compacted at the end of the compression stroke of the piston the pressure will be in- creased to forty-five, sixty, and even seventy-five pounds per square inch. At the end of this compression stroke, which is shown at B, the conditions in the engine cylinder are the same as those which prevail in the barrel of the cannon -after the powder has been tightly rammed in the closed end of the gun barrel and the ball is forced in on top of it. At C we have seen that the powder was fired by means of a fuse. The compressed gas in the engine cylinder is exploded elec- trically by a spark occurring between the points of the spark plug. The explosion in the cannon drives out the ball, while that in the 106 The Modern Gasoline Automobile engine cylinder forces the piston out and causes the crank shaft and fly wheel attached to it, to revolve. In order to obtain a perfectly tight combustion chamber, both intake and exhaust valves are closed before the gas is ignited, because all of the pressure produced by the exploding gas is to be directed against the top of the movable piston. When the piston reaches the bottom of its power stroke, as indicated at D, the exhaust valve is lifted by means of the bell crank which is rocked because of the point or lift on the cam. The cam shaft is driven by positive gearing and revolves at half the engine speed. The exhaust valve remains open during the whole of the return stroke of the piston, and as this mem- ber moves toward the closed end of the cylinder it forces out burned gases ahead of it, through the passage controlled by the exhaust valve. The cam shaft is revolved at half the engine speed because the ex- haust valve is raised from its seat during only one stroke out of four, or only once every two revolutions. Obviously, if the cam was turned at the same speed as the crank shaft it would remain open once every revolution, whereas the burned gases are expelled only once in two turns of the crank shaft. It will be evident that three strokes of the piston are necessary to secure one useful explosion just as practically three operations are needed to fire the cannon. The first downward movement of the piston fills the cylinder with gas and is known as the " intake stroke." This is accomplished during the first half revolution of the crank shaft. The return movement of the piston is accomplished during the second half of the first revolution and compacts the gas previously inspired. This is called the " compression stroke." The expansive force back of the piston produced by the explosion forces the piston down again, this turning the crank shaft through the first half of the second revolution which is known as the " power stroke." The last half of the second revolution produces a return movement of the piston toward the closed end, and as the burned gases are expelled and the cylinder is cleared to receive the fresh charge, this movement of the piston is known as the " exhaust stroke." The cycle of opera- tions described is continued and repeats as long as the cylinder is supplied with fuel, the spark takes place to fire the gas and the engine prevented from overheating by means of lubrication between 107 108 The Modern Gasoline Automobile all moving parts and cooling those portions liable to become exces- sively hot by suitable extraneous means. Typical Single-Cylinder Engines Described. The gasoline engine may have any number of cylinders, though the conventional types used in automobile propulsion seldom use any but an even number and rarely more than six. At one time single-cylinder motors were very popular. These were used in both the horizontal and vertical types. A typical form of horizontal motor is shown at Fig. 33. Power plants of this type were, for the most part, of low power and were patterned largely after stationary gasoline engine practice as far as proportion of parts was concerned. They were heavy and oper- ated at low speed. Such engines are seldom employed at the present time, except in cars of ancient construction, many of which are still in use. Though this type of motor was comparatively slow acting and considerable vibration existed while it was in operation, they were strongly constructed and capable of giving very satisfactory service. Engines of this type are usually installed under the body, the engine cylinder being parallel with the frame side member while the crank shaft was at right angles to it. This permitted a very simple and efficient method of power transmission as the change speed gearing which was usually carried on the crank shaft extension could be easily coupled to the rear axle by means of a single chain and a pair of sprockets. Owing to the vibration which obtains from the heavy explosion in the large single-cylinder engine other forms were evolved in which the cylinder was smaller and power obtained by running the engine faster. The single-cylinder motor of the vertical type is shown at Fig. 34. The pattern shown at Fig. 33 is distinctively of American derivation and was designed to avoid the rapid wearing and noisy acting single-cylinder motors of the foreign vertical type. When a single-cylinder engine is employed a very heavy fly wheel is needed to carry the moving parts through idle strokes necessary to obtain a power impulse. For this reason modern designers prefer to use more than one cylinder, and the tendency is to produce power by frequently occurring light impulses rather than by a smaller number, of explosions having greater force. When a single-cylinder motor is employed the construction is heavier than is needed with a multiple- The Modern Gasoline Automobile 109 cylinder form. Using two or more cylinders conduces to steady power generation and a lessening of vibration. Most modern motor cars employ four-cylinder engines because a power impulse may be secured twice every revolution of the crank shaft, or a total of four-power strokes during two revolutions. The parts are so arranged that while the charge of gas in one cylinder is exploding, those which come next in firing order are compressing, discharging the inert gases and drawing in a fresh charge respectively. When the power stroke is Value Lifters Connecting Hod Fig. 34. Sectional View of Brush Runabout Motor, a Simple Single- Cylinder Power Plant of the Vertical Type, Designed to Operate at High Speeds. completed in one cylinder, the piston in that member in which a charge of gas has just been compressed has reached the top of its stroke and when the gas is exploded the piston is reciprocated and keeps the crank shaft turning. When a four-cylinder engine is used tin- 11 v wlii'd is much lighter than that of the single-cylinder form. In fact, many modern four-cylinder engines developing thirty horse power weigh less than the early single-cylinder forms which developed but one-third or one-fourth that amount of energy. Single Cylinder Ttvo Cylinder Vertical Cranhpins on Same Plane Two Cylinder, Opposed Cranhpins At J 80 Degrees Fig. 35. Diagrams Illustrating Sequence of Cycles in One- and Two-Cylinder Engines Show More Uniform Turning Effort on Crank Shaft with Two- Cylinder Motors. 110 The Modern Gasoline Automobile 111 Describing Sequence of Operations. Referring to Fig. 35, A, the uf operation in a single-cylinder motor can be easily under- stood. Assuming that the crank shaft is turning in the direction of the iirniw. it will be seen that the intake stroke conies first, then the com- pression, which is followed by the power impulse, and lastly the exhaust stroke. If two cylinders are used, it is possible to balance the ex- plosions in such a way that one will occur each revolution. This is true with either one of two forms of four-cycle motors. At B, a two- cylinder vertical engine using a crank shaft in which the crank pins are on the same plane is shown. The two pistons move up and down simul- taneously. Referring to the diagram describing the strokes, and as- suming that the outer circle represents the cycle of operations in one cylinder while the inner circle represents the sequence of events in the other cylinder, while cylinder No. 1 is taking in a fresh charge of gas, cylinder Xo. 2 is exploding. When cylinder Xo. 1 is compressing, cylinder Xo. 2 is exhausting. During the time that the charge in cylinder Xo. 1 is exploded, cylinder Xo. 2 is being filled with fresh gas. While the exhaust gases are being discharged from cylinder Xo. 1, cylinder Xo. 2 is compressing the gas previously taken in. The same condition obtains when the crank pins are arranged at one hundred and eighty degrees and the cylinders are opposed, as shown at C. The reason that the two-c} r linder opposed motor is more popular than that having two vertical cylinders is that it is difficult to balance the construction shown at B, so that the vibration will not be excessive. The two-cylinder opposed motor has much less vibra- tion than the other form, and as the explosions occur evenly and the motor is a simple one to construct, it has been very popular in the past on light cars. To demonstrate very clearly the advantages of multiple-cylinder engines the diagrams at Fig. 36 have been prepared. At A, a three- cylinder motor, having crank pins at one hundred and twenty degrees, which means that they are spaced at thirds of the circle, we have a form of construction that gives a more even turning than that pos- sible with a two-cylinder engine. Instead of one explosion per revo- lution of the crank shaft, one will obtain three explosions in t\\<> revolutions. The manner in which the explosion strokes occur and the manner they overlap strokes in the other cylinder is shown at A. 112 The Modern Gasoline Automobile Assuming that the cylinders fire in the following order, first No. 1, then No. 3, and last No. 2, we will see that while cylinder No. 1, represented by the outer circle, is on the power stroke, cylinder No. 3 has completed the last two-thirds of its exhaust stroke and has started on its intake stroke. C} r linder No. 2, represented by the middle circle, during this same period has completed its intake stroke and two-thirds of its exhaust stroke. A study of the diagram will show that there is an appreciable lapse of time between each explosion. In the four-cylinder engine operation which is shown at Fig. 36, B, it will be seen that the power strokes follow each other without loss of time, and one cylinder begins to fire and the piston moves down just as soon as the member ahead of it has completed its power stroke. In a four-cylinder motor, the crank pins are placed at one hundred and eighty degrees, or on the halves of the crank circle. The crank pins for cylinder No. 1 and No. 4 are on the same plane, while those for cylinders No. 2 and No. 3 also move in unison. The diagram describing sequence of operations in each cylinder is based on a firing order of one, two, four, three. The outer circle, as in previous in- stances, represents the cycle of operations in cylinder one. The next one toward the center, cylinder No. 2, the third circle represents the sequence of events in cylinder No. 3, while the inner circle outlines the strokes in cylinder four. The various cylinders are working as follows : 1. 2. 3. 4. Explosion Exhaust Intake Compression Compression Explosion Exhaust Intake Exhaust Intake Compression Explosion Intake Compression Explosion Exhaust It will be obvious that regardless of the method of construction, or the number of cylinders employed, exactly the same number of parts must be used in each cylinder assembly and one can conveniently com- pare any multiple-cylinder power plant as a series of single-cylinder engines joined one behind the other and so coupled that one will de- liver power and produce useful energy at the crank shaft where the, other leaves off. The same fundamental laws governing the action of a single cylinder obtain when a number are employed, and the Firing Order 1,3,2 1 3 Three Cylinder, Cranks At 120 Degrees Firing Ordzr J. 2.4,3 Four Cylinder, Cranhs At 750 Degrees First Reuoluticn Second /?< 780' 760' ICO" Fig. 36. Diagrams Demonstrating Clearly Advantages which Obtain when Multiple-Cylinder Motors are Used as Power Plants. 113 114 The Modern Gasoline Automobile sequence of operation is the same in all members, except that the necessary functions take place at different times. If, for instance, all the cylinders of a four-cylinder motor were fired at ihe same time, one would obtain the same effect as though a one-piston engine was used, which had a piston displacement equal to that of the four smaller members. As is the case with a single-cylinder engine the motor would be out of correct mechanical balance because all the connecting rods would be placed on crank pins that lie in the same plane. A very large fly wheel would be necessary to carry the piston through the idle strokes, and large balance weights would be fitted to the crank shaft in an effort to compensate for the weight of the four pistons, and thus reduce vibratory stresses which obtain when parts are not in correct balance. There would be no advantage gained by using four cylinders in this manner, and there would be more loss of heat and more power consumed in friction than in a one-piston motor of the same capacity. This is the reason that when four cylinders are used the arrangement of crank pins is always as shown at Fig. 36, B i. e., two pistons are up, while the other two are at the bottom of the stroke. With this construction, we have seen that it is possible to string out the explo- sions so that there will always be one cylinder applying power to the crank shaft. The explosions are spaced equally. The parts are in correct mechanical balance because two pistons are on the upstroke while the other two are descending. Care is taken to have one set of moving members weigh exactly the same as the other. With a four-cylinder engine one has correct balance and continuous applica- tion of energy. This insures a smoother running motor which has greater efficiency than the simpler one-, two-, and three-cylinder forms previously described. Eliminating the stresses which would obtain if we had an unbalanced mechanism and irregular power application makes for longer life. Obviously a large number of relatively light explosions will produce less wear and strain than would a lesser num- ber of powerful ones. As the parts can be built lighter if the explo- sions are not heavy, the engine can be operated at higher rotative speeds than when large and cumbersome members are utilized. The six-cylinder type of motor, the action of which is shown at Fig. 36, C, is superior to the four-cylinder, inasmuch as the power The Modern Gasoline Automobile 115 strokes overlap, and instead of having two explosions each revolution we have three explosions. The conventional crank-shaft arrangement in a six-cylinder engine is just the same as though one used two three- cylinder shafts fastened together so pistons 1 and 6 are on the same plane as are pistons 2 and 5. Pistons 3 and 4 also travel together. With the cranks arranged as outlined at Fig. 36, C, the firing order is one, five, three, six, two, four. The manner in which the power strokes overlap is clearly shown in the diagram. An interesting comparison is also made in the small diagram in the upper left-hand corner of this view. A rectangle is divided into four columns ; each of these correspond to one hundred and eighty degrees, or half a revolution. Thus the first revolution of the crank shaft is represented by the first two col- umns, while the second revolution is represented by the last two. Taking the portion of the diagram which shows the power impulse in a one-cylinder engine, we see that during the first revolution there has been no power impulse. During the first half of the second revo- lution, however, an explosion takes place and a power impulse is ob- lained. The last portion of the second revolution is devoted to ex- hausting the burned gases, so that there are three idle strokes and but one power stroke. The effect when two cylinders are employed is shown immediately below. Here we have one explosion during the first half of the first revo- lution in one cylinder and another during the first half of the second revolution in the other cylinder. With a four-cylinder engine there is an explosion each half revolution, while in a six-cylinder engine there is one and one-half explosions during each revolution. When six cylinders are used there is no lapse of time between power impulses, as these overlap and a continuous and smooth-turning movement is imparted to the crank shaft. While the six-cylinder engine has ob- vious advantages, it will be evident that it must be fifty per cent more complicated than the four-cylinder, and as one obtains a smooth- acting engine with the lesser number, the majority of engineers favor the four-cylinder type of power plant for general service. Actual Duration of Different Strokes. In the diagrams presented at Figs. 35 and 36, the writer has assumed, for the sake of simplicity, that each stroke takes place during half of one revolution of the 116 The Modern Gasoline Automobile crank shaft, which corresponds to a crank-pin travel of one hundred and eighty degrees. The actual duration of these strokes is somewhat different. For example, the inlet stroke is usually a trifle more than a half revolution, and the exhaust is always considerably more. The Fig. 37. Diagram Showing Actual Duration of Different Strokes in Degrees. diagram showing the comparative duration of the strokes is shown at Fig. 37. The inlet valve opens ten degrees after the piston starts to go down and remains open thirty degrees after the piston has reached the top of its stroke. This means that the .suction stroke cor- responds to a crank-pin travel of two hundred degrees, while the com- The Modern Gasoline Automobile 117 pression stroke is measured by a movement of but one hundred and sixty degrees. It is common practice to open the exhaust valve before the piston reaches the end of the power stroke so that the actual dura- tion of the power stroke is about one hundred and forty degrees, while the exhaust stroke corresponds to a crank-pin travel of two hundred and twenty-five degrees. In this diagram, which represents proper time for the valves to open and close, the dimensions in inches given are measured on the fly wheel and apply only to the " Model M " Thomas motor. If the fly wheel were smaller ten degrees would take up less than the dimensions given, while if the fly wheel was larger a greater space on its circumference would represent the same crank- pin travel. Spark Plug Cylinder Connecting Rod Fig. 38. Simple Form of Two-Cylinder Motor Having Opposed Cylinders; a Very Popular Form of Power Plant for Light Service. Typical Engine Types Described. A very simple and efficient type of power plant is shown at Fig. 38. In this motor the cylinders are horizontally disposed and opposed to each other. The valves are car- ried in a pocket, or chamber, on top of the cylinder and they are oper- ated by direct push-rod movement from a cam shaft carried just above the crank shaft. The general arrangement of parts is clearly 118 The Modern Gasoline Automobile outlined, and as each component is indicated there should be no diffi- culty in grasping the details of this form of power plant. The motor illustrated at Fig. 39 is a simple four-cylinder type of modern con- struction and may be considered representative of standard practice. In this motor it will be seen that the four cylinders are arranged on a crank case common to them all. The crank case also acts as a sup- porting member for the crank shaft and cam shaft. A section of the crank case is broken away to show the crank-shaft design, and also to illustrate the method employed of raising the valves from their Fig. 39. Sectional View of Four-Cylinder Motor, the Most Widely Used Type of Multiple Engine. seats by means of cams. The front cylinder is not sectioned. The second cylinder, which is immediately back of it, is sectioned through the valve chest in order to show the gas passages and the method of closing them by mushroom valves. Cylinder No. 3 is divided on its center line to show the piston and connecting rod assembly, while the last cylinder is sectioned in such a way that the construction of the piston, connecting rod, and wrist pin is clearly shown. Another type of four-cylinder engine sectioned in a somewhat similar manner with all parts indicated is shown at Fig. 40. A 119 120 The Modern Gasoline Automobile careful study of this illustration should familiarize one with the gen- eral arrangement of the parts of conventional power plants. The views shown at Figs. 39 and 40 are longitudinal sections. In order Fig. 41. Sectional View of Rear Cylinder of Gasoline Engine with Important Parts Indicated. to show the appearance of the parts of an engine when one of the cylinders is cut in such a manner that it is viewed from the end rather than from the side, such a section is given at Fig. 41. As is the case in other illustrations all parts are clearly indicated. This The Modern Gasoline Automobile 121 view is also valuable in showing the arrangement of some of the aux- iliary components, such as the water pump, which is used to circulate the cooling liquid; the carburetor, which is employed to furnish the explosive mixture; and the magneto, which is supplied to ignite the compressed gas. The exhaust pipe, which is attached to the side of the cylinder to carry away the burned gases, and the sump, or oil con- tainer, which carries a supply of the lubricant to keep the working surfaces free, are also outlined. Features of the Knight Slide Valve Motor. One of the latest ten- dencies of engineers responsible for the design of motor-car power plants is toward the elimination of all noises incidental to their opera- tion. Much of this has been attributed to operation of the valves and in order to reduce the clatter, types of engines in which the poppet, or mushroom, valves are replaced by sliding or revolving elements are being extensively experimented with. The earliest types of explosion motors, as evolved by Lenoir, Bray- ton, and Otto, employed simple slide valves which were patterned after those used in steam engines. Owing to faulty construction these early forms were not successful, as considerable difficulty was expe- rienced from warping and in keeping the cylinder tight enough to retain gas pressure. In several engines of recent development the mushroom valves are being replaced by sleeves which have a more gradual motion and which slide by ports in the cylinder instead of being brought forcibly in contact with the seats by a strong spring. An advantage of the slide valve motor, which is perhaps even more important than that of silence, is the increased flexibility and aug- mented power developed, because the large gas passages permit the entering stream of fresh vapor, or the departing current of inert gas to leave the cylinder without being impeded. The disadvantage often cited against poppet valves 'is that at high speeds they fail to follow the contour of their actuating cams accurately and there is consider- able loss of power because of the irregular gas flow. The most practical and satisfactory of the valveless motors now in Qge was invented by Charles Y. Knight, an American engineer, sev- < mi years ago. When first introduced in this country it was met with considerable ridicule, and the inventor was forced to take his inven- tion to Europe, where its advantages met with prompt recognition. 122 The Modern Gasoline Automobile Fig. 42. Comparing Poppet Valve and Sliding Sleeve Valve Power Plants. Upper View Shows Knight Engine with Sleeves to Control Gas Ports. Lower Illustration Shows Gas Passages Controlled by Mushroom Valves. The Modern Gasoline Automobile 123 The Knight valveless motor is now made and used by such celebrated automobile manufacturers as, Daimler, in England; Panhard-Levas- sor, in France ; Minerva, in Belgium ; and Mercedes, in Germany. In this country it will be found on models of the Columbia, Stearns, and Stoddard-Dayton. The operating principles in this engine do not differ materially from other four-cylinder, four-cycle types, the only difference being in the method of admitting and expelling gases from the cylinder. The illustrations at Fig. 42 show very clearly the difference which exists between the slide valve and the conventional poppet valve motor. Both of" these are the same in general design, except that changes have been made in the power plant to permit the use of reciprocating sleeves. The upper illustration represents the slide valve motor in part section, while the lower view shows the conventional poppet valve type. The Knight motor has four cylinders cast in pairs. The top of ;u h cylinder has two lateral slots which communicate respectively with the inlet and exhaust pipes. The cylinder is water-jacketed, and inside of this member and interposed between it and the piston sin- t\vo thin, hollow cast-iron cylinders, or sleeves, adapted to be moved up and down by a suitable crank shaft and connecting rod mechanism or eccentrics. These sleeves have large ports which com- municate with the orifices in the cylinder wall. They are moved in such a manner that the slots in the cylinder are opened and closed by the reciprocating movement of the sleeves. They are operated by small connecting rods which work from a smaller crank shaft mounted to one side of, and above the main crank shaft, and driven by silent chain gearing. The travel of the sleeves is comparatively small, as their velocity is but one-tenth that of the piston. The open- ings in the sleeves are so wide that the gases enter and leave the combustion chamber much more easily than they could through ports rli-si-il by valves of the conventional type. The movement of the sleeves is such that the ports in the cylinder are closed by one or both sleeves during three-quarters of the cycle of operation, and are kept open during the remaining quarter by a simultaneous lining up of the openings in both sleeves with that in the cylinder. As is the case with a four-cycle motor of the conven- 124 The Modern Gasoline Automobile 125 tional pattern during the first downstroke of the piston the inlet port is opened and the exhaust orifice closed. During the next two piston strokes, one up and the other down, corresponding to the com- pression and explosion of the gas, both ports are kept closed. Then during the last upstroke, which corresponds to the scavenging period, the exhaust port is opened and the inlet port closed. It is claimed that this motor is very silent at high speeds, and it is more flexible in operation than other forms. It is also said that this type of motor will retain its compression longer than the poppet valve type, because there can be no escape of gas through the ports when they are closed by the sleeves. The moving members are lubri- cated in the usual manner, the only precaution taken being to insure an even distribution of oil by cutting a spiral groove and boring a number of holes in each sleeve. The great advantage of this type over the poppet valve motor can be very well shown by comparing the illustrations at Figs. 43 and 44, which show action of the valves used on the ordinary motor with the views at Figs. 46 and 47. At Fig. 43, A, the position of the piston, crank shaft, cam, and intake valve are shown at the beginning of the charging stroke. It will be noticed that the intake valve has just barely left its seat and that there will be little space for the gases to flow into the cylinder until the piston has reached the position shown at Fig. 43, B, at which point the inlet valve is fully opened. From this point to that outlined at Fig. 43, C, the inlet valve closes and the gas passage becomes more and more restricted as the piston travels down. The same condition obtains when the exhaust valve is operated. It lifts gradually, and the full opening is not attained until the parts have assumed the position shown at Fig. 44, B. From this point to that outlined at Fig. 44, C, the valve is closing. It will be evident that with mushroom valves one attains the maximum port opening only during the time that the cam follower rides on the point of the cam which is but an instant. The cam roller follows the cam profile only at low and moderate speeds. When the velocity increases the cam will throw the push rod instead of lifting it and the action will be erratic. Incidentally, these views show very clearly the method of valve operation and will prove valuable in assisting the reader to gain an idea of valve timing which will be discussed at length in proper sequence. 126 The Modern Gasoline Automobile 127 The view at Fig. 45 is a simplified section which shows the parts of the Knight type motor to advantage. The diagrams at Figs. 46 and 47 will enable the reader to see the relation of the sleeves at dif- ferent points in the cycle of opera- tion. At Fig. 46, A, the position at the inception of the intake stroke is clearly shown. At B the parts have assumed positions that permit the fresh gas to flow quickly into the cylinder. At C the sleeves are closed. It will be apparent that one obtains a clear port through which the gases may flow easily as soon as the intake stroke begins. This is increased in value until the maximum open- ing is reached, just as with a pop- pet valve. The important point to observe, however, is that there is always a straight passage for the gas to flow through while the port is open. Even when the pop- pet valve has been raised to the highest point there is still diffi- culty for the gas to leave the cylinder because of the tortuous passage and the number of turns the gas stream must make to enter and leave the combustion chamber. Fig. 47 depicts the movement of the sliding sleeve valves on the ex- haust stroke. In order to obtain uniform power application and a smooth running engine it is essential that the gases in each cylinder be com- pressed to the same value before Fig. 45. End Sectional View of Knight Sliding Sleeve Type Motor, Show- ing Sleeves which Take Place of the Poppet Valves of Conventional Mo- tors. A Outer Valve Shell, fi- lmier Valve Shell. C Operating Lever for A. D Operating Lever for B. E Lay Shaft. F Crank Shaft. G Helical Gears. H Valve Opening. K Cylinder Head. L Sparking Plug Holes. O Cross - Shaft Driving Pump and Magneto. U Piston. 128 The Modern Gasoline Automobile ignition takes place. If the compression is less in one cylinder then that member will be doing less work than the others and the rotative speed will not be constant. The crank shaft will slow up when it comes to the weak cylinder, and will accelerate when the three strong ones are acting on it. It is claimed that in the Knight motor the absolute constancy of compression makes for uniformity of action because the intervals between the successive explosions are always equal and all of the power strokes have the same strength. It is also advanced that the construction of the Knight motor makes it possible to obtain combustion chambers which are equal in volume, which con- dition is difficult to attain with the ordinary construction, because of the difficulty m^t in securing perfect equality of castings. As the cylinders and cylinder heads of the Knight motor are machined to the required dimensions and polished, all combustion chambers will have the same volume. Another advantage is that there will be no projecting particles of metal such as would be present in castings that might remain hot and cause premature explosions. It is also difficult for carbon to adhere to the absolutely smooth walls of the combustion chamber or piston head. There is very little strain on the parts, and as the wear of the sleeves is negligible the motor action improves Avith service, because the sleeves become polished and work easier the more they are used. As the sleeves are driven by cranks and connecting rods and not by cams as poppet valves are, they are not liable to go wild at even the highest motor speeds. The ports are opened and closed exactly at the proper time, and the openings or passages for the gas are so large that the motor capacity augments with an increase of speed. In a comparative test of two similar motors, one with mushroom valves and the other with sleeves, the former developed but twenty- five horse power at 2,000 revolutions per minute, while the sleeve type generated in excess of thirty horse power under the same con- ditions. The Knight motor has been subjected to severe tests before adoption in comparison with motors of the poppet valve type. In one of these an engine rated at thirty-eight horse power which had cylinders of 5-inch bore and stroke developed 55.3 horse power con* tinuously during a period of 5^2 days, or 132 hours. The fuel con- sumption was but 0.85 pint of gasoline per horse power hour. The Sparh Plugs Exhaust Fig. 46. Diagrams Depicting Action of Sliding Sleeves on Intake Stroke. Port About to Open. B Inlet Port Fully Open. C Inlet Port Closed. Water Pipe Fig. 47. Diagrams Illustrating Movement of Sliding Sleeve Valves on the I C Exhau *5troke. A Exhaust Port About to Open. B Exhaust Port Fully Open. tClosed. The Modern Gasoline Automobile 129 average fuel consumption of the four-cycle type of motor is placed at one pint per horse power hour. At the completion of this running in test the power plant was installed in a car weighing 4,000 pounds. This was driven over 2,000 miles on Brooklands Motor Track, near London, England, at a speed which averaged forty-three miles per hour. At the completion of this test the motor was replaced on a test stand in the shop where it developed an average of 57.25 horse power during a run of five hours at 1,'200 revolutions per minute. The fuel consumption was reduced to 0.75 pint of gasoline per horse power hour and it had gained two horse power, or about four per cent ay use. This type of valveless motor is considered to be an improvement over the conventional forms, and it is all the more strange when one considers that the height of its development has been reached at a time when all believed the explosion motor had attained its maximum efficiency. The success attending the use of the Knight motor has promoted great interest in all forms of valveless motors which are jeing actively experimented with at the present time. Some of the most successful of these types will be described in detail in the fol- owing chapters. Operating Principles of Two-Cycle Engines. While the majority of automobiles use four-cycle internal combustion engines for propul- sion there are cases where the simpler two-stroke cycle motor has been used. Though it has been widely used in marine applications for years it has not become very popular in motor-car service. If con- sidered from a theoretical point of view the two-cycle- engine has important advantages, and if ideal conditions were obtained in practice, motors of this type would develop twice the amount of power obtain- able from four-cycle engines having the same number of cylinders, equal piston displacement and operating at the same crank shaft speed. The two-cycle motor is much simpler than the other forms, and it has but three moving parts per cylinder. In this type a power im- pulse is obtained with each downstroke of the piston instead of every other downstroke. With the explosion occurring twice as often the energy delivered is increased in direct proportion and a more even turning movement of the crank shaft results because of the more 130 The Modern Gasoline Automobile rapid series of explosions. It has been shown that with the four- stroke engine three operations are necessary to obtain a useful power impulse. The first downward movement of the piston draws in the gas. The following upward movement compresses the mixture. The second down movement of the piston takes place during the expan- sion or explosion stroke, and is the third and power-producing part of the cycle. Following this operation the remaining stroke of the piston, which is upward, clears the cylinder of burned gas. Obviously all the work is done at the top of the piston, and the differing functions take place in the combustion chamber or that por- tion of the cylinder above the piston. With a two-cycle engine all this work can be accomplished in half the number of strokes, and it is possible to secure an explosion stroke after each idle stroke. There is a power impulse every revolution of the crank shaft for each cylin- der instead of every two turns, and energy is created every two strokes of the piston. To accomplish this, work is performed on both sides of the piston, as the crank case is utilized as well as the part of the cylinder above the piston. The top of this member compresses the charge and receives the pressure of the explosion, as these two essential functions can only take place in that portion of the cylinder above the piston. The crank case performs the duty of the inspiration stroke, as the mixture is drawn into the engine base by the upwardly moving piston. This is done at the same time that the piston is mov- ing up to compress the gas above it, previously taken in. The views at Fig. 48 show the principles of operation of two-port, two-cycle engines, while those at Fig. 49 define the fundamentals of three-port two-cycle engine operation. The principle in the main is the same for both types, the only difference being in the method of introducing the gas to the crank case. It will be seen that such engines are very simple, and that the pistons, connecting rods, and crank shaft are the only moving parts. Instead of valves and operating mechanism to control the gas flow by ports, or passages which are cast in the cylinder walls about halfway down their length are used. The gas is taken into the engine base, which is air tight, and of small capacity ; in one case through an auto- matic check valve fitting to which the carburetor is attached. In the three-port form this valve is eliminated and the carburetor is coupled 131 132 The Modern Gasoline Automobile directly to the cylinder. The gas is transferred from the crank case to the cylinder through a bypass, or a passage leading from the engine base to the intake port. Considering first the action of the two-port, two-cycle type it will be evident that if the base is air tight an upward movement of the piston will produce a suction in the engine base, drawing the inlet valve down from its seat and inspiring a mixture of gasoline and air from the carburetor. Thus when the piston moves up, the engine base fills with vapor. On the down movement of the piston the gas in the crank case is compressed, and when the top of the piston reg- isters with the inlet port in the side of the cylinder the mixture will transfer to the cylinder above the piston because of its pressure. The intake port is opened as the piston side uncovers it. The compres- sion in the engine base is light compared to that above the piston. While the compression pressure before ignition may be as high as eighty pounds per square inch, that in the engine base necessary to insure prompt transfer of the charge seldom exceeds ten pounds. The operation of this type engine is not difficul't to understand. Eeferring to Fig. 48, A, we will assume that there is a compressed charge of gas above the top of the piston, and that the crank case is full of mixture. The spark occurs at the spark plug and the resulting explosion forces the piston down on its power stroke, this movement also compressing the gas already in the engine base. When the piston uncovers the exhaust port it begins to open before the intake port is uncovered and the burned gases escape to the air because of their pressure. After the exhaust port has been open for a small period the inlet port is uncovered by the piston which is still on its downward movement. The compressed gas in the case flows through the bypass and into the cylinder. It cannot escape out of the open exhaust port opposite, because the deflector directs the gases toward the top of the cylinder. The fresh gas coming in tends to force out any of the burned residue which tends to remain. As the piston rises on the return stroke both ports are closed and the gas in the cylinder is com- pressed. Simultaneously with the gas compression the partial vacuum created in the engine base draws in new mixture from the carburetor through the open check valve. Three-port engine operation, as shown at Fig. 49, is very similar 134 The Modern Gasoline Automobile to that previously described, except that the intake port in the cylin- der to which the carburetor is coupled is uncovered by the piston only when it has traveled up in the cylinder. There is a pronounced vacuum in the crank case when this port is uncovered and the rapid rush of gas insures quick charging. The three-port engine is con- siderably faster than the two-port type, and is more popular for motor- car service. In the three-port form of engine the mixture rushes in to fill the engine base as a body, whereas in the two-port type it is drawn in gradually during the whole upstroke of the piston. If the reader compares the views of the simple two-cycle engines shown, with the four-cycle types previously described, it will be seen that the former are simpler, because many of the small parts necessary for the successful action of a four-stroke motor are not needed in the two-stroke motor. The valves and operating mechanism are dis- pensed with, which means elimination of the cam shafts, driving gear- ing, cams, and push rods, incidental to valve operation. As the cylin- der of the two-cycle engine is charged and cleaned through simple ports which are but orifices left after cutting away part of the cylinder wall, the gas can be introduced and discharged with much less mech- anism. The ports are covered by the piston until the time comes when they are needed. In the two-port form both openings are opened fully only when the piston reaches the end of the downstroke, but in the three-port motor the remaining opening through which the crank case is charged is uncovered when the piston reaches the end of its upward movement. The simple forms of two-cycle motors described have been replaced in some cases by types in which the preliminary compression of gas in the crank case has been eliminated. This is accomplished by the use of a two-diameter piston, as shown at Fig. 50. The cylinder proper consists of an upper and lower chamber. The small portion of the piston fits the upper cylinder while the enlarged part fits the lower end. Instead of the gas being inspired into the engine base it is drawn into the enlarged portion of the cylinder. It has been diffi- cult to maintain regularity of two-cycle motor action when crank case compression was used, because any leakage at the bearings, or pack- ings in the crank case, meant a reduction in vacuum and made for uncertain charging. The Modern Gasoline Automobile 135 With the construction outlined at Fig. 50, the gas is taken into the large portion of the main cylinder, and as the pumping piston is provided with packing rings just as the working piston is, it is not difficult to keep a tight charging chamber. The positions of the pistons in the various cylinders of a four-cylinder motor using a dif- ferential piston arrangement are shown at Fig. 50. It will be seen that a rotary distributing valve must be used to permit the gas to enter the pump cylinder and flow into the working cylinder at the right time; this is turned by gearing from the crank shaft. Fig. 50. Explaining Action of Differential Piston Type of Two-Cycle Engine. At A the piston is going up and a charge of gas is being com- : pressed in both the working cylinder and the pump cylinder. At B, which represents the section through cylinder No. 2, the piston is moving down under the influence of the explosion and the pumping piston is drawing in a charge of gas through the distributing valve which is in communication with the inlet pipe. At C a section through cylinder No. 3 is shown. The working piston in this case has reached the top of its stroke and is ready to receive the impact due to the explosion of the charge. At D a section through cylinder No. 1 is outlined. The cylinder valve has made communication with the pumping chamber of cylinder No. 3, as shown at C, and a charge of gas is being transferred to the working cylinder No. 1. The burned gases are expelled through the open exhaust port in the usual manner and admitted by the customary intake port adjacent to the deflector plate. The action in this type of engine may be easily un- 136 The Modern Gasoline Automobile derstood if one considers that the pumping chamber of one cylinder is employed to draw in gas and compress it prior to transferring it to the working chamber of another cylinder. Why Two-Cycle Motor is not Widely Used. It has been previously stated that the four-cycle motor is almost universally used, and to properly understand the reason for the preponderance of this type over the simpler two-cycle forms it is necessary to compare the actual results obtained from the two-stroke motor in ordinary practice with the advantages a purely theoretical consideration will give it. There are a number of problems to be solved before the two-cycle motor will compare with the other type in efficiency. To obtain maximum power it is necessary that a full charge of explosive gas enter the cylinder: that this mixture must be properly proportioned; that it should be compacted to a certain point before ignition, and that it must be ignited promptly and at the proper time. In order to obtain a full charge of pure mixture it is evident that the exhaust gases must be entirely expelled from the cylinder in order that the incoming fresh gas will not be contaminated by mixing with the dead products of combustion. It is much more difficult to secure a full charge of clean mixture with a two-cycle engine than with a four-cycle. In the former, the charging with fresh gases and expulsion of dead gases must take place in half the time allowed in the latter form, and the piston does not pump in a charge or force the burned gases out of the cylinder, as is the case with a four-stroke engine. As the two-cycle motor does not fully expel the burned products it cannot run as fast because of a tendency to choke up at high speeds. In the four-cycle engine a full stroke of the piston is employed in emptying the cylinder, and the natural gas pressure is increased by the reduction of cylinder volume caused by the upwardly moving piston. In the two-cycle forms the burned gas is discharged through the open exhaust port by its own pressure. If prompt charging and clearing of the cylinder was the only problem to be solved in securing efficient action it would not be difficult to provide large enough ports to attain this end. The port size must be restricted, however, and carefully proportioned because as both intake and exhaust passapvs are uncovered by the piston at practically the same time a large por- The Modern Gasoline Automobile 137 tion of the incoming gas may be discharged with the burned product, tliis making for a large fuel consumption and material reduction of efficiency. As the gas is not perfectly clean and pure, some difficulty may be experienced in igniting it. Trouble is also experienced with the cooling, lubrication, and carburetion groups, as most two-cycle motors have peculiarities which make proper oiling and gas supply difficult. Most automobile designers have adopted the four-cycle power plant, because it has been perfected to a greater degree than the two- cycle, and is easier to keep adjusted and in good running condition. Though the two-cycle motor is undoubtedly the simplest form, it is liable to be erratic in operation and it is sometimes difficult to locate the trouble positively. They consume more fuel than the four-cycle engine of the same power and are not so economical as regards use of lubricating oil. Various types of two-cycle engines which have been designed for automobile use will be described in a following chapter. Power Plant Installation. The method of installing the power plant varies on different types of automobiles, though the majority of cars have the engine placed at the extreme front end of the chassis. In some types of cars where single or double cylinder motors of the horizontal type are used the motor is placed under the body. This type of construction is nearly obsolete at this time, and is found only on early forms of vehicles and one or two commercial cars. The power plant is sometimes combined with the clutch and change speed gearing in such a way as to form a unit construction. This method of joining the parts is widely used at the present time, and is superior to the other common method where the motor and change speed gears are independent units. Each method has advan- tages. As will be seen by inspecting Fig. 51, A, when the gearset and motor are separate the transmission may be removed from the < iiassis frame without disturbing the power plant and vice versa. At the other hand, when the unit construction, as shown at B, is em- ployed, it is sometimes difficult to remove one member without having to take the entire unit from the frame. The unit construction has the advantage of retaining positive alignment of the gearset with the engine indefinitely. This relation 138 The Modern Gasoline Automobile between the parts is obtained when they are first assembled and the alignment cannot be changed by any condition of operation after the unit is installed in the frame. This method of mounting also per- mits the three-point suspension which is very desirable. For in- stance, the power plant shown at A is supported on four points and the gearset is supported on another series of four points. While the tendency of these members is to brace the frame and prevent dis- Fig. 51. Defining Advantages of Unit Power Plant Construction when Sup- ported on Three Points. alignment, it is possible on extremely rough roads for- the frame distortion to vary the relation of the transmission and engine shaft to some extent. Where a three-point suspension is employed, as out- lined at B, the frame distortion will not impose stress on the indi- vidual members of the power plant because in a rigid unit construc- tion all parts must remain in alignment. The advantages of this The Modern Gasoline Automobile 139 dt-siirn arc becoming better appreciated and it is widely used at the present time. Fig. 52. Four-Cylinder Power Plant and Transmission Unit Adapted for Three- Point Support. At Fig. 52, a typical four-cylinder power plant and transmission unit adapted for three-point support is clearly shown, while at Fig. 53 a six-cylinder unit power plant which. is designed for attachment to the frame at four points is illustrated. To show the method of power- Fig. 63. Six-Cylinder Unit Power Plant Utilized in Knox Motor Car is Sup- ported by Four Points. Fig. 54. Views of Typical Power Plant as Installed in Motor-Car Frame, The Common Method of Installation in Pleasure Cars. 140 The Modern Gasoline Automobile 141 plant installation that is generally employed, the views at Fig. 54 are presented, these representing a typical four-cylinder power plant viewed from the front and rear, snowing clearly the method, of sup- porting the engine base by four arms and also outlining the position of the various auxiliary components. In some types of commercial vehicles the motor is installed at the front end under the hood as in pleasure ear practice, but in other cases it is placed at practically tin- same point but under floor boards or driver's seat. The advantages of the motor under the seat location may be very well summed up by saying that it permits more loading space and or all or wheel base for a given carrying capacity. The shorter wheel base vehicle is especially valuable in congested city traffic, be- cause it may be more easily controlled when driving in narrow thor- oughfares, taking corners, or backing up to a loading platform. The main advantage advanced for the motor in front type of commercial vehicle is accessibility of power plant, which may be easily reached by raising the hood. This feature is not lost when the motor is placed under the seat, however, because all average adjustments may be made ly raising the floor boards or by opening a hinged door at the side ] of the motor compartment. Some makers who install the motor under |the seat arrange the components in such a manner that they may be removed as units permitting ready access to the motor and making 'for its prompt removal in event of overhauling or serious accident. Such a construction is shown at Fig. 55, which depicts a light truck with the seat and dash units removed from the frame. It will be seen that the dash unit includes the radiator, control levers, fuel tank and frame, for' the support of the floor boards. The seat unit is sep- arate and is designed to fit over the dash unit when it is in place on the chassis. 142 CHAPTER III The Principal Parts of Gasoline Engines Their Design, Construction, and Practical Application in Typical Power Plants Treating of the Cylinders, Valve System and Valve Timing, Rotary Valve Types, Combination Piston and Sleeve Valve Operation, Ring and Distributor Valve Motor Con- struction. THE improvements noted in the modern internal combustion mo- : tors have been due to many conditions. The continual experimenting I by leading mechanical minds could have but one ultimate result. The I parts of the engines have been lightened and strengthened, and greater power has been obtained without increasing piston displace- ment. A careful study has been made of the many conditions which I make for efficient motor action, and that the main principles are j well recognized by all engineers is well shown by the standardization I of design noted in modern power plants. There are many different 1 methods of applying the same principle, and it will be the purpose of this chapter to define the ways in which the construction may be changed and still achieve the same results. The various components may exist in many different forms, and all have their advantages and ', disadvantages. That all methods are practical is best shown by the ) large number of successful cars which use radically different designs. Methods of Cylinder Construction. One of the most important purls of the gasoline engine and one that has material bearing upon its efficiency is the cylinder unit. Of late there hae been a tendency to depart from the previous methods of casting the cylinders individu- ;illy, or in pairs, and make all cylinders a unit or block casting. Some typical methods of cylinder construction are shown at Fig. 56. The appearance of individual cylinder castings of two different types are shown at A and B. In the former, the cylinder and cylinder head are cast integral and the valves are supported by inserted cages. In fit- i \ Under design shown at B, the head member is a separate casting from that forming the cylinder, and the valves seat directly in this 143 Fig. 66. Illustrating Differing Methods of Cyl- inder Construction Commonly Employed. A Single or One-Cylinder Casting Used on Jack- son Cars. B Individual Cylinder Forming Part of Knox Power Plant. C Typical Twin Casting Generally Used on Motor Car Engines. D Four Cylinders Cast in One Block, a Fea- ture of the Chalmers " 30 " Motor. 144 The Modern Gasoline Automobile 145 member. It is held to the cylinder by means of four bolts. The casting shown at C comprises two cylinders and is the usual form. That at D is a block casting in which the four cylinders are cast together and conforms to up-to-date practice. Considered from a purely theoretical point of view the individual cylinder casting has much in its favor. It is advanced that more uniform cooling is possible than where the cylinders are cast either in pairs or three or four in one casting. More uniform cooling in- sures that the expansion or change of form due to heating will be more equal. This is an important condition because the cylinder bore must remain true under all conditions of operation. If the heating effect is not uniform, which condition is liable to obtain if metal is not evenly distributed, the cylinder may become distorted by heat and the bore be out of truth. When separate cylinders are used it is possible to make a uniform water space and have the cooling liquid evenly distributed around the cylinder. In multiple cylinder castings this is not always the rule, as in many instances, especially in four- cylinder block motors where compactness is the main feature, there is no space between the cylinders for the passage of water. Under such circumstances the cooling effect is not even, and the stresses which obtain because of unequal expansion may distort the cylinder to some extent. The advantage of casting the cylinders in blocks is that a motor may be much shorter than it would be if individual castings were used. It is admitted that when the cylinders are cast together a more compact, rigid, and stronger power plant is obtained than when cast separately. There is a disadvantage, however, in that if one cylinder becomes damaged it will be necessary to replace the entire unit, which means scrapping three good cylinders because one of the four has failed. When the cylinders are cast separately one need only replace that one that has become damaged. The casting of four cylinders in one unit is made possible by improved foundry methods, find when proper provision is made for holding the cores when the metal is poured and the cylinder casts are good, the construction is one of distinct merit. It is sometimes the case that the proportion of sound castings is less when cylinders are cast, in block, but if the proper precautions are observed in molding and the proper mixtures 146 The Modern Gasoline Automobile of cast iron used, the ratio of defective castings is no more than when cylinders are molded individually. As an example of the courage of modern motor-car engineers in departing from old-established rules, the cylinder casting shown at Fig. 57 may be considered typical. This is a remarkable departure from standard construction, because not only Fig. 57. Block Casting of Everitt " Six," a Remarkable Innovation in Motor Design Because Six Cylinders, Upper Part of Crank Case and Inlet and Exhaust Manifolds are Included in One Casting. the six cylinders are cast in a block but the upper part of the engine base and the inlet and exhaust manifold are also included in the one casting. A method of construction which is attracting some attention at the present time is that shown at Fig. 58. This is a four-cylinder motor in which the four cylinders and the top half of the crank case are cast together, but it employs a separately cast head member which is common to all cylinders. This is held to the cylinder casting by means of a series of bolts, and a copper-asbestos gasket, or packing, is utilized in making a gas- and water-tight joint between the parts, The advantage of this construction is that it permits ready access to pistons and valves without dismantling the entire motor as is neces- The Modern Gasoline Automobile 147 sary when the conventional form of cylinder casting is employed. This type of construction is also used on some motors having indi- vidually cast cylinders. The member shown at Fig. 56, B, which forms a part of Knox power plant, has a separately cast head, and this construction is also followed in the sleeve valve motors of the Knight type previously described, and in the Argyle motor which is illustrated at Fig. 59. Fig. 58. Example of Four-Cylinder Block Motor having One Separately Cast Head Member Common to All Cylinders. A Copper-Asbestos Gasket is Utilized in Making a Gas- and Water-Tight Joint Between the Parts. Note Accessibility of Pistons and Valves. It is common practice to cast the water jackets integral with the cylinders, and this is also the most economical method of applying it because it gives good results in practice. An important detail is that the water spaces must be proportioned so that they are equal around 148 The Modern Gasoline Automobile the cylinders whether these members are cast individually, in pairs, threes or fours. When cylinders are cast in block form it is good prac- tice to leave a large opening in the jacket wall which will assist in supporting the core and make for uniform water space. It will be noticed that the casting shown at Fig. 56, D, has a large opening in the side of the cylinder block. These openings are closed after the interior of the casting is thoroughly cleaned of all sand, core wire, etc., by brass, cast iron or aluminum plates. These also have particular value in that they may be removed after the motor has been in use, thus permitting one to clean out the interior of the water jacket and dispose of the rust, sediment, and incrustation which are always present after the engine has been in active service for a time. Among the advantages claimed for the practice of casting cylinders in blocks may be mentioned compactness, lightness, rigidity, simplic- ity of water piping, as well as permitting the use of simple forms of inlet and exhaust manifolds. The light weight is not only due to the reduction of the cylinder mass but because the block construction per- mits one to lighten the entire motor. The fact that all cylinders are cast together decreases vibration, and as the construction is very rigid, disalignment of working parts is practically eliminated. When inlet and exhaust manifolds are cored in the block casting, as is sometimes the case, but one joint is needed on each of these instead of the multi- plicity of joints which obtain when the cylinders are individual cast- ings. The water piping is also simplified. In the case of a four- cylinder block motor but two pipes are used; one for the water to enter the cylinder jacket, the other for the cooling liquid to discharge through. Influence on Crank-Shaft Design. The method of casting the cylin- ders has a material influence on the design of the crank shaft as will be shown in proper sequence. When four cylinders are combined in one block it is possible to use a two-bearing crank shaft. Where cylin- ders are cast in pairs a three-bearing crank shaft is commonly sup- plied, and when cylinders are cast as individual units it is thought necessary to supply a five-bearing crank shaft, though sometimes shafts having but three journals are used successfully. Obviously the shafts must be stronger and stiffer to withstand the stresses imposed if two supporting bearings are used than if a larger number are em- Inlet Pipe Detachable 'Cylinder Heacf Exhaust Pipy Fig. 59. Showing Separate Head Construction of Argyl Sleeve Valve Motor, Made Necessary by Use of Sleeve. 149 150 The Modern Gasoline Automobile ployed. In this connection it may be stated that there is less difficulty in securing alignment with a lesser number of bearings and there is also less friction. At the other hand, the greater the number of points of support a crank shaft has the lighter the webs can be made and still have requisite strength. Combustion Chamber Design. Another point of importance in the design of the cylinder and one which has considerable influence upon the power developed, is the shape of the combustion chamber. The endeavor of designers is to obtain maximum power from a cylinder of certain proportions, and the greater energy obtained without increas- ing piston displacement or fuel consumption the higher the efficiency of the motor. To prevent troubles due to preignition it is necessary that the combustion chamber be made so that there will be no rough- ness, sharp corners, or edges of metal which may remain incandescent when heated or which will serve to collect carbon deposits by provid- ing point of anchorage. With the object of providing an absolutely clean combustion chamber some makers use a separable head unit such as shown at Fig. 56, B, and Figs. 58 and 59. These permit one to machine the entire interior of the cylinder and combustion chamber. The relation of valve location and combustion chamber design will be considered in proper sequence. Bore and Stroke Ratio. A question that has been a vexed one and which has been the subject of considerable controversy is the proper proportion of the bore to the stroke. The early gas engines had a certain well-defined bore to stroke ratio, as it was usual at that time to make the stroke twice as long as the bore was wide, but this cannot be done when high speed is desired. With the development of the present-day motor the stroke or piston travel has been gradually short- ened so that the relative proportions of bore and stroke have become nearly equal. Of late there seems to be a tendency among designers to return to the proportions which formerly obtained and the stroke is sometimes one and a half or one and three-quarter times the bore. Engines designed for high speed should have the stroke not much longer than the diameter of the bore. The disadvantage of short- stroke engines is that they will not pull well at low speeds, though they run with great regularity and smoothness at high velocity. The long-stroke engine is much superior for slow speed work, and it will The Modern Gasoline Automobile 151 pull steadily and with increasing power at low speed. It was formerly thought that such engines should never turn more than a moderate number of revolutions in order not to exceed the safe piston speed. Water Space Combustion C*amoe Spark Plug Valve Cap Cxhaust an,fol/ Cylinder Fig. 63. Diagrams Demonstrating Advantages of Off-set Crank-Shaft Con- struction. Another important advantage is that greater efficiency is obtained from the explosion with an off-set crank shaft, because the crank is already inclined when the piston is at top center and all the energy imparted to the piston by the burning mixture can be exerted directly into producing a useful turning effort. When a cylinder is placed di- rectly on a line with the crank shaft, as shown at A, it will be evident that some of the force produced by the expansion of the gas will be 156 The Modern Gasoline Automobile 157 exerted in a direct line and until the crank moves the crank throw and connecting rod are practically a solid member. The pressure which might be employed in obtaining useful turning effort is wasted by causing a direct pressure upon the lower half of the main bearing and the upper half of the crank-pin bushing. Very good and easily understood illustrations showing advantages of the off-set construction are shown at E and F. This is a bicvcle \. (, M^-^ 1J\ \^-l ^J \ i.UJ^-p s Fig. 65. Section Through Typical Four-Cylinder Block Motor with Three- Bearing Crank Shaft. crank hanger. It is advanced that the effort of the rider is not as well applied when the crank is at position E as when it is at position F. Position E corresponds to the position of the parts when the cylinder H placed directly over the crank-shaft center. Position F may be compared to the condition which is present when the off-set cylinder construction is used. Influence of Cylinder Construction on Engine Design. To show the manner in which the various methods of casting cylinders previously 158 The Modern Gasoline Automobile 159 defined may alter engine design some views of typical power plants are presented. That at Fig. 64 is a part sectional view of the Sheffield Simplex, an English six-cylinder motor. In this the cylinders are cast in blocks of three, and the motor is composed of two blocks. A seven-bearing crank shaft is used, there being a journal between each pair of cylinders in addition to the two end members. A feature of this power plant that may be commended is the exceptionally good water jacketing of the cylinders. The water spaces are large and all |.aris of the cylinder are surrounded by cooling liquid. Individual Cylinder 'Breather Pipe Rtar Bearing Fig. 67. Sectional View of Typical Four-Cylinder Motor Using Individual Cylin- der Castings with Cylinder Heads Cast Integral. General Design Fair, Excepting that of Connecting Rods. At Fig. 65 a section through a typical four-cylinder block motor is given. In this power plant a short crank case is used, but the rnmk sliiii't. is supported on three bearings instead of two journals as is com- mon practice with four-cylinder motors. To show the use of indi- 160 The Modern Gasoline Automobile vidual castings the motors shown at Figs. 66 and 67 are valuable. It will be evident if these are compared to Fig. 65 that the motor will have a greater overall length than when all cylinders are cast in one block. In the motor shown at Fig 66 a five-bearing crank shaft is employed while that at Fig. 67 uses a three-bearing crank shaft. There are a number of other constructional details dependent upon cylinder design which merit detailed description such as valve placing and operation, crank case design, etc., but these are of sufficient im- portance to be discussed in a more comprehensive manner and will be considered separately. Valve Location of Vital Import. It has often been said that a chain is no stronger than its weakest link and this is as true of the explosive motor as it is of any other piece of mechanism. Many motors which appeared to be excellently designed and which were well constructed did not prove satisfactory, because some minor detail or part had not been properly considered by the designer. A factor having material bearing upon the efficiency of the internal combustion motor is the location of the valves and the shape of the combustion chamber which is largely influenced by their placing. The fundamental consideration of valve design is that the gases be admitted and discharged from the cylinder as quickly as possible in order that the speed of gas flow will not be impeded and produce back pressure. This is imperative in ob- taining satisfactory operation in any form of motor. If the inlet passages are constricted the cylinder will not fill with explosive mix- ture promptly, whereas if the exhaust gases are not fully expelled the parts of the inert products of combustion retained dilute the fresh charge, making it slow burning and causing lost power and overheat- ing. When an engine employs water as a cooling medium this sub- stance will absorb the surplus heat readily, and the effects of over- heating are not noticed as quickly as when air-cooled cylinders are employed. Valve sizes have a decided bearing upon the speed of mo- tors and some valve locations permit the use of larger members than do other positions. While piston velocity is an important factor in determinations of power output it must be considered from the aspect of the wear pro- duced upon the various parts of the motor. It is evident that engines which run very fast, especially of high power, must be under a greater The Modern Gasoline Automobile 161 strain than those operating at lower speeds. The valve-operating mechanism is especially susceptible to the influence of rapid move- ment, and the slower the engine the longer the parts will wear and the more reliable the valve action. As will be seen by reference to the accompanying illustrations, there are many ways in which valves may be placed in the cylinder. Each method outlined possesses some point of advantage because all of the types illustrated are used by reputable automobile manu- facturers. The method outlined at Fig. 68, A, is widely used and because of its shape the cylinder is known as the " T " form. It is approved for several reasons, the most important being that large valves can be employed and a well-balanced and symmetrical cylinder casting obtained. Two independent cam shafts are needed, one op- erating the inlet valves, the other the exhaust members. The valve- operating mechanism can be very simple in form, consisting of a plunger actuated by the cam which transmits the cam motion to the valve stem, raising the valve as the cam follower rides on the point of the cam. Piping may be placed without crowding, and larger mani- folds can be fitted than in some other constructions. This has special value, as it permits the use of an adequate discharge pipe on the ex- haust side with its obvious advantages. At the other hand, if considered from a viewpoint of actual heat efficiency, it is theoretically the worst form of combustion chamber. This disadvantage is probably compensated for by uniformity of ex- pansion of the cylinder because of balanced design. The ignition spark plug may be located directly over the inlet valve in the path of the incoming fresh gases, and both valves may be easily removed and inspected by unscrewing the valve caps without taking off the mani- folds. The valve installation shown at D is somewhat unusual, though it provides for the use of valves of large diameter. Easy charging is insured because of the large inlet valve directly in the top of the cyl- inder. Conditions may be reversed if necessary, and the gases dis- charged through this large valve. Both methods are used, though it would seem that the free exhaust provided by allowing the gases to escape directly from the combustion chamber through the overhead valve to the exhaust manifold would make for more power. The 102 The Modern Gasoline Automobile 163 inroming fresh gas cannot fail to flow into the cylinder easily, because it is drawn into the cylinder by the pumping action of the piston, whereas if the inert gas is not expelled promptly the factor of back Rocker Arm Valve Cage Fig. 69. Benz Racing Motor, Presented to Show Method of Valve Placing so these Members Open Directly into the Cylinder Head. \ 164 The Modern Gasoline Automobile pressure is of some importance. The method outlined at Pig. 69 is one that has been widely employed on large racing motors where ex- treme power as required as well as in engines constructed for regular service. The inclination of the valve cages permits the use of large valves and these open directly into the combustion chamber. There are no pockets to retain heat or dead gas, and free intake and outlet of gas is obtained. This form is quite satisfactory from a theoretical point of view because of the almost ideal combustion chamber form. Some difficulty is experienced, however, in properly water-jacketing the valve chamber which experience has shown to be necessary if the engine is to have high power. The motor shown at Fig. 62 employs a c} r linder of the " L " type. Both valves are placed in a common extension from the combustion chamber, and being located side by side both are actuated from a com- mon cam shaft. The inlet and exhaust pipes are placed on the same side of the engine and a very compact assemblage is obtained. The valves may be easily removed if desired, and the construction is fairly good from the viewpoint of both foundry man and machinist. The chief disadvantage is the limited area of the valves and the loss of heat efficiency due to the pocket. This form of combustion chamber, however, is more efficient than the " T " head construction, though with the latter the use of larger valves probably compensates for the greater heat loss. It has been stated as an advantage of this construc- tion that both manifolds can be placed at the same side of the engine and a compact assembly secured. At the other hand, the disadvantage may be cited that in order to put both pipes on the same side they must be of smaller size than can be used when the valves are oppo- sitely placed. The " L " form cylinder may be made more efficient if but one valve is placed in the pocket while the other is placed in the cylinder head. This construction is well shown at Fig. 70, which is a side sectional view of the same motor depicted in end section at Fig. 68, B. The large valves one can use are well emphasized in this illus- tration. The method of valve application shown at Fig. 71 is an ingenious method of overcoming some of the disadvantages inherent with valve- in-the-head motors. In the first place it is possible to water-jacket the valves thoroughly, which is difficult to accomplish when they are The Modern Gasoline Automobile 165 mounted in cages. The water circulates directly around the walls of the valve chambers which is superior to a construction where separate are used, as there are two thicknesses of metal with the latter, Fig. 70. Part Sectional View of Bergdoll Motor, Showing Placing of Valves. The Exhaust Member is Fitted in a Side Pocket of the L Cylinder. The Inlet Valve is Placed Directly in the Center of the Combustion Chamber. I that of the valve cage proper and the wall of the cylinder. The cool- ing medium is in contact only with the outer wall, and as there is always a loss of heat conductivity at a joint it is practically impossi- ble to keep the exhaust valves and their seats at a uniform temper- 166 The Modern Gasoline Automobile ature. The valves may be of larger size without the use of pockets Avhen seating directly in the head. In fact, they could be equal in diameter to almost half the bore of the cylinder, which provides an ideal condition of charge placement and exhaust. SEAT GUIDE Fig. 71. Cylinder Head of Knox Engine Cut in Two to Show Method of Valve Placing and Seating Directly in Separately Cast Member. Valves Operated by Rocker Arms. Note Exceptionally Good Water Spaces Around Valve Seats. When valve grinding is necessary the entire head is easily removed by taking off four nuts and loosening inlet and exhaust manifold con- nections, which operation would be necessary even if cages were employed. The cylinder is easily cast and machined, and as the head is separately water- jacketed there is no water joint between the head and cylinder which must be made tight with a packing capable of resisting both water and hot gas. The sole junction of the copper asbestos washer which fits in the annular groove in the cylinder head is to prevent escape of gas. The ease with which the head and cylin- der may be machined and smooth combustion chamber obtained lias been previously dealt with. The Modern Gasoline Automobile 167 The form shown at Fig. 72 shows an ingenious application of the va I \c-in-the-head idea which permits one to obtain large valves. It has been used on some of the Franklin air-cooled cars. The inlet pas- sage is controlled by the sliding sleeve which is hollow and slotted so as to permit the exhaust gases to leave the cylinder and out through the regular type poppet valve which seats in the inlet sleeve. When EXHAUST 15 SPRING Fig. 72. Section Through Concentric Valve Used on Some Franklin Models. The Exhaust Valve, which is a Regular Poppet Type, Seats in the Inlet Mem- ber, which is a Hollow Shell of Metal. Both Valves Open Directly into the Combustion Chamber. the inlet sleeve is operated by the tappet rod and rocker arm the ex- haust valve is also carried down with it. The exhaust gas passage is closed, however, and the fresh gases are taken in through the large annular passage surrounding the inlet sleeve. When the inlet valve 168 The Modern Gasoline Automobile Fig. 73. Section Through Cylinder of Hudson Car. A Typical Form Having L-shaped Cylinder with Inlet and Exhaust Valves on Same Side of Cylinder and Actuated from Common Cam Shaft. Note Plate Used to Enclose Valve Springs. . The Modern Gasoline Automobile 169 leaves its seat in the cylinder the passage of cool gas around the sleeve keeps the temperature of both valves to a low point and the danger of win-ping is minimized. A dome-shaped combustion chamber may be usi-d which is an ideal form in conserving heat efficiency and as large valves may be installed the flow of both fresh and exhaust gases may be obtained with minimum resistance. At Fig. 73 a section through a typical " L "-shaped cylinder is depicted. It will be evident that where a pocket construction is em- ployed in addition to its faculty for absorbing heat, the passage of gas would be impeded. For example, the inlet gas rushing in through the open valve would impinge sharply upon the valve cap directly over the valve and then must turn at a sharp angle to enter the com- bustion chamber and then at another sharp angle to fill the cylinders. The same conditions apply to the exhaust gases, though they are re- versed. When the valve-in-the-head type of cylinder is employed the only resistance offered the gas is in the manifold. As far as the pas- sage of the gases in and out of the cylinder is concerned ideal condi- tions obtain. It is claimed that valve-in-the-head motors are more flexible and responsive than other forms but the construction has the disadvantage in that the valves must be opened through a rather complicated system of push rods and rocker arms instead of the sim- pler and direct plunger which can be used with either the " T " or " L " head cylinders. Valve Design and Construction. Valve dimensions are an im- portant detail to be considered and can be determined by several con- ditions, among which may be cited method of installation, operating mechanism, material employed, engine speed desired, manner of cyl- inder cooling, and degree of lift desired. A review of various methods of valve location has shown that when the valves are placed directly in the head, we can obtain the ideal cylinder form though larger valves may be used if housed in a separate pocket, as afforded by the " T " head construction. The method of operation has much to do with tin- size of the valves. For example, if an automatic inlet valve is employed it is good practice to limit the lift and obtain the required area of port opening by augmenting the diameter. Because of this a valve of the automatic type is usually made twenty per cent larger than one mechanically operated. When both are actuated by cam 170 The Modern Gasoline Automobile mechanism, as is now common practice, they are usually made the same size and are interchangeable, which greatly simplifies manufac- ture. The relation of valve diameter to cylinder bore is one that has been discussed for some time by engineers. The writer's experience would indicate that they should be at least half the bore, if possible. The larger the area of the valve the less lift required, and this is an important factor where high rotative speeds are desired. A valve with a small lift will reach its maximum opening sooner and close quicker than one with a high lift and small diameter. This will produce less wear on the parts and tend to more silent operation. At the other hand, a large diameter valve is more apt to warp than a narrower one, and greater care is needed in securing positive cooling Key Slot * Seat Cast Iron Head 45% Seat A Nickel Steel Fig. 74. Type of Valves in Common Use. A One-Piece Steel Valve of Good Design which Permits Easy Gas Flow. B Steel Valve Made by Electric- ally Welding a Nickel Steel Head to a Carbon Steel Stem. C A Con- struction Often Employed for Exhaust Valves, a Two-Piece Built-Up Mem- ber. D Valve with Flat Seat, Often Used to Admit Mixture to Cylinder. when large diameter members are used. While the mushroom type or poppet valve has become standard and is the most widely used form at the present time, there is some difference of opinion among designers as to the materials employed and the angle of the seat. Most valves have a bevel peat, though some have a flat seating, as shown at Fig. 74, D. The flat seat valve has the distinctive advantage of providing a clear opening with lesser lift, this conducing to free gas flow. It also The Modern Gasoline Automobile 171 has value because it is silent in operation, but the disadvantage is pres- ent that best material and workmanship must be used in their con- struction to obtain satisfactory results. As it can be made very light it is particularly well adapted for use as an automatic inlet valve. Among other disadvantages cited is the claim that it is more sus- o-ptilile to derangement owing to the particles of foreign matter get- ting under the seat. With a bevel seat valve it is argued that the foreign matter would be more easily dislodged by the gas flow, and that the valve would close tighter because it is drawn positively against the hovel seat. Several methods of valve construction are the vogue, the most popular form being the one-piece type; though those which are com- posed of a head of one material and stem, of another are often used. Jf the built-up construction is favored the head is usually of high nickel steel, Monel metal, or cast iron, which metals possess good heat resisting qualities. Heads made of these materials are not likely to warp, scale, or pit, as is sometimes the case when ordinary grades of machinery steel are used. The cast-iron head construction is not popular because it is often difficult to keep the head tight on the stem. There is a slight difference in expansion ratio between the head and the stem, and as the stem is either screwed or riveted to the cast-iron head the constant hammering of the valve against its seat may loosen the joint. As soon as the head is loose on the stem the action of the valve becomes erratic. The valve shown at Fig. 74, A, is made from a forging of thirty-five per-cent nickel steel in the large sizes, and is often machined from the bar liy automatic machinery in making the smaller sizes. Among the fat tors considered in design are to make the stems of ample size so that they will not be likely to bend, and to leave enough metal between the stem and the head so that the gases may be directed toward the periph- ery of the head. This has a tendency to make a slightly heavier valve than that shown at Fig. 74, B. It is also considered good practice to use a domed or arched head instead of one that is perfectly flat, and it is advisable to leave the head smooth and without a slotted boss which is often left on so that a screw-driver blade can be used to turn the valve when grinding it. When the arched head construction is used two small holes may be drilled into it. These have the advantage of 172 The Modern Gasoline Automobile leaving no sharp edges exposed to retain heat and cause too early ex- plosions of gas. If desired, a slot may be cut directly in the head and the valve turned with a screw-driver. The form of valve shown at B is a common one, and its only advantage is that the design permits of light construction. The slotted boss is not desirable for the reason previously outlined, the valve head is not as strong as that shown at A and it will warp sooner. The point of weakness where the stem joins the head may cause trouble. As the gases strike the under surface and are sharply de- flected at a sharp angle instead of having an easy flow the passage is somewhat impeded. The form of construction is a nickel steel head electrically welded to a machinery steel stem. The former material is a better heat-resisting substance while the softer steel makes a bet- ter bearing. The joint is indistinguishable because the metals are fused together, and that point is as strong as any other part of the stem. The valve shown at C is composed of a cast-iron head member screwed on to a steel stem. The construction at D is a good example of flat seat inlet valve. Fig. 75. Forms of Valve-Lifting Cams Generally Employed. A Cam Profile for Long Dwell and Quick Lift. B Typical Inlet Cam Used with Mush- room Type Follower. C Average Form of Cam. D Designed to Give Quick Lift and Gradual Closing. Valve Operation. The methods of valve operation commonly used vary according to the type of cylinder construction employed. In all cases the valves are lifted from their seats by cam actuated mechan- ism. Various forms of valve-lifting cams are shown at Fig. 75. As will be seen, a cam consists of a circle to which a raised, approximately triangular member has been added at one point. When the cam fol- Tlic Modern Gasoline Automobile 173 lower rides on the circle, as shown at Fig. 76, there is no difference in height between the cam center and its periphery and there is no move- ment of the plunger. As soon as the raised portion of the cam strikes the plunger it will lift it, and this reciprocating movement is trans- mitted to the valve stem by suitable mechanical connections. The cam forms outlined at Fig. 75 are those commonly used. That at A is used on engines where it is desired to obtain a quick lift and to keep the valve fully opened as long as possible. It is a noisy form, however, and is not very widely employed. That at B is utilized more often as an inlet cam while the profile shown at C is generally de- pended on to operate exhaust valves. The cam shown at D is a com- posite form which has some of the features of the other three types. It will give the quick opening of form A, the gradual closing of form B, and the time of maximum valve opening provided by cam profile C. Fig. 76. Showing Principal Types of Cam Followers which Have Received General Application. The various types of valve plungers used are shown at Fig. 76. That shown at A is the simplest form, consisting of a simple cylindri- cal member having a rounded end which follows the cam profile. These are sometimes made of square stock or kept from rotating by 174 The Modern Gasoline Automobile means of a key or pin. A line contact is possible when the plunger is kept from turning whereas but a single point bearing is obtained when the plunger is cylindrical and free to revolve. The plunger shown at A will follow only cam profiles which have gradual lifts. The plunger shown at B is left free to revolve in the guide bushing and is provided with a flat mushroom head which serves as a cam fol- lower. The type shown at C carries a roller at its lower end and may follow very irregular cam profiles if abrupt lifts are desired. While forms A and B are the simplest, that outlined at C in its various forms is more widely used. The illustrations at Fig. 77 show some of the different possible methods of valve operation. At A the application of a rocker arm and tappet rod to operate an overhead valve is clearly depicted. The rocker arm is interposed in order that the upward movement of the tappet rod will produce a down movement of the valve stem. The method of valve operation shown at B is possible when it is desired to operate both valves of a " T " head cylinder from a common cam shaft. One of the valves is lifted directly by the usual cam actuated plunger, while the other member is raised from its seat by a plunger operated from the cam through a centrally pivoted simple lever. At C the simplest method of valve operation is shown. The cylinder cast- ing is a twin " L " form, and the valves are placed side by side in the pocket at one side of center. They are operated directly by means of simple mushroom head plungers guided in bushings secured in bosses formed integrally with the cylinder base. These plungers bear against the lower end of the valve stems. All the methods in which levers are used to operate valves are more or less noisy because clearance must be left between the valve stem and the top of the plunger. The space must be taken up before the valve will leave its seat, and when the engine is operated at high speeds the forcible contact between the plunger and valve stem produces a pro- nounced hammering sound. At D a method of indirect valve opera- tion is shown. The main purpose is to obtain silent working and to permit the valves being arranged in any convenient position. Instead of using direct cam action against the end of the valves, the valves are lifted from their seats by a liquid under pressure. The cams are placed across the front of the engine, though they could be placed at Rocker Arm Tappet Rod Fig. 77. Defining Different Possible Methods of Valve Operation. A Over- head Valve Actuated by Rocker Arm, Tappet Rod and Roller Type Cam Follower. B Both Valves Operated from One Cam, " T " Head Cylinder. C Valves of " L " Type Twin Cylinder Casting Operated by Mushroom Type Cam Followers. D Suggested Method of Indirect Valve Operation. 175 176 The Modern Gasoline Automobile any other point so long as they could be conveniently driven from the crank shaft. There are eight cams, one for each valve, and under each cam an oil force pump is placed. This is connected by a tube to a plunger under the valve stem. Each pipe is filled with oil, and when the cam operates its particular pump the incompressible liquid in the pipe is forced against the plunger under the valve and the valve is lifted. In- stead of the cam pushing the tappet and the plunger pushing the valve, as in other constructions described, the cam works a pump and this in turn a tappet. The return of the valve stem is effected by the valve springs in the usual way. Each oil pump is also provided with a return spring which keeps the roller on top of the pump plunger bearing against the cam. The whole of the cam action is in an oil bath and any leakage of liquid from the pipes is automatically com- pensated for through a simple form of ball valve. Each pipe is always full of oil as long as there is any in the bath. As it is not possible to compress the liquid, it may be stated broadly that the driving effect is the same as though the oil pipes were filled with steel balls. The simile is not a correct one, because the fluid pressure provides a softness and silence of action which could not be very well obtained by direct operation. It is also expected that clear- ance between the valve stem and operating plungers will not be neces- sary because the slight leakage of working fluid will compensate for any expansion of the valves and the resulting lengthening of the stems automatically. It is not expected that this method of valve operation will be used to any extent because the mechanism is more complicated than when simple direct lift plungers are employed. With modern forms of plungers which are provided with suitable adjusting features which make it possible to maintain a minimum clearance between valve stem and lifting member, the valve action is silent enough so that it would not pay to introduce a complicated hydraulic system as that described. This has been presented mainly to show that valves may be operated by other means than direct cam and plunger action. We have seen that the method of valve placing has material bear- ing on the system of valve-actuating mechanism employed. At Fig. 78 the various methods of valve installation are presented in diagram- matic form and will assist the reader in obtaining a clear idea of the The Modern Gasoline Automobile 177 valve placings most commonly used. With the " T " head cylinder as shown at A separate cam shafts are usually employed and the valves, are raised by direct lift plungers. The " L " head cylinder as de- N Fig. 78. Diagram Showing Forms of Cylinder Demanded by Different Valve Placings. A T Head Type, Valves on Opposite Sides. B L Head Cylinder, Valves Side by Side. C L Head Cylinder, One Valve in Head, Other in Pocket. D Inlet Valve Over Exhaust Member, Both in Side Pocket. E Valve-in-the-Head Type with Vertical Valves. F Inclined Valves Placed to Open Directly into Combustion Chamber. 178 The Modern Gasoline Automobile picted at B calls for but one cam shaft, and as is true of the previous case the valves may be lifted directly from their seats by a simple cam follower. At C the valve location demands the use of an overhead rocker arm which may be actuated from the same cam shaft which is employed to raise the exhaust valve from its seat. At D a method of valve placing is shown which is very popular on small motors used for motorcycle propulsion. The inlet valve is placed directly over the exhaust member and may be automatically operated or may be de- pressed by the conventional form of rocker arm. When overhead valves are used, as shown at E, two rocker arm assemblies are needed and both valves are operated from a common cam shaft. With the form shown at F having inclined valves two sets of rocker arms may be Pig. 79. Cam Shaft and Valve Operating Plunger Case of Hupp Motor, a Separ- ate Member. Note Simple Type of Cam Follower. used actuated by two cam shafts, one on each side of the motor. Sometimes a single rocker arm is fulcrumed at the center, having one extremity bearing on each valve stem. The lever is rocked by a special form of cam provided with a depression as well as a raised portion. When the tappet rod is raised it may depress one of the valves, whereas when the cam follower drops in the depression of the cam the other end- of the rocker arm will fall and open the other valve. A cam case assembly, such as used on the Hupp motor, is shown at The Modern Gasoline Automobile 179 Fig. 79. This is bolted to the side of the engine base and the large gear at iat lied to the cam shaft is driven from a suitable gear on the crank shaft at half the engine speed. The cam followers are the simple form shown at Fig. 76, A. They are provided with a fiber inset at their top end which comes into contact with the valve stem. The use of this material tends to reduce noise which would be present if two metals came in contact. - Methods of Driving Cam Shaft. Two systems of cam shaft opera- tion are used. The most common of these is by means of gearing of some form. If the cam shaft is at right angles to the crank shaft it may be driven by worm, spiral, or bevel gearing. If the cam shaft is parallel to the crank shaft, simple spur gear or chain connection may be used to turn it. At Fig. 80 a conventional system of cam gears is shown. The front of the gear case has been removed, this exposing the gear train which drives the cam shaft and accessory mechanism. A small gear having thirty-two teeth is placed on the crank shaft. This engages a larger member having sixty-four teeth turning it at one-half its speed. This large gear is securely fastened to a flange on the cam shaft by three bolts. At the right an idler gear meshes with the crank-shaft gear and serves to transmit motion from that member to the small gear at the extreme right which is utilized to drive the circulating pump shaft and the magneto employed for ignition. While gearing is more commonly used, considerable attention has been directed of late to silent chains for cam shaft operation. The ordinary forms of block or roller chain have not proven successful in this application, but the silent chain, which is in reality a link belt operating over toothed pulleys, has demonstrated its worth. The tendency to its use is more noted on foreign motors than those of American design. It first came to public notice when employed on the Daimler-Knight engine for driving the small auxiliary crank shafts which reciprocated the sleeve valves. At Fig. 81 two efficient cam shaft drives are illustrated. That at A is furnished on the Wolseley 1912 motors. It will be observed that the small gear on the crank shaft is coupled to a larger gear on the cam shaft by one chain, while a separate gear wheel and chain drives the magneto from the cam shaft. The sprockets are so proper- 180 The Modern Gasoline Automobile tioned that the cam shaft revolves at half the engine speed, while the magneto is speeded up so it will have the same speed as the crank shaft. CRANKSHAFT Of. AK Fig. 80. Front View of Warren-Detroit " 30 " Motor with Timing Gear Case Cover Removed to Show Arrangement of Cam Shafts and Water Pump Driving Gears. The Modern Gasoline Automobile 181 At Fig. 81, B, the silent chain drive on the White & Poppe engines is shown. This installation is similar in the main to that previously described, and further description is not needed. The advan- tages cited for the application of chains are, first, silent operation which obtains even after the chains have worn considerably; second, in designing it is not necessary to figure on maintaining certain abso- lute center distances between the crank shaft and cam shaft sprockets, Fig. 81. Showing Use of Silent Chain Connection Between Crank Shaft and Cam Shaft, and also for Driving Water Pump and Magneto Shafts. A Chain Drive on Wolseley (English) 1912 Motor. B Method of Using Silent Chains on White & Poppe (English) Power Plant. as would be the case if conventional forms of gearing were used. On some forms of motor employing gears, three and even four members are needed to turn the cam shaft. With a chain drive but two sprock- et- arc necessary, the chain forming a flexible connection which per- mit- the driving and driven members to be placed at any distance a | art that the exigencies of the design demand. When chains are used it is advised that some means for compensating chain slack be provided or the valve timing will lag when chains are worn. Many combination drives may be worked out with chains that would not be possible with other forms of gearing. It is expected that there will be a irradual tendency on the part of American designers to incorporate the silent chain drive in their product. 182 The Modern Gasoline Automobile Valve Springs. Another consideration of importance is the use of proper valve springs, and particular care should be taken with those of automatic valves. The spring must be weak enough to allow the valve to open when the suction is light and must be of sufficient strength to close it in time at high speeds. It should be made as large as possible in diameter and with a large number of convolutions, in order that fatigue of the metal be obviated, and it is imperative that all springs be of the same strength when used on a multiple-cylinder engine. On the exhaust valve the spring must be strong enough so that the valve will not be sucked in on the inlet stroke. It should be borne in mind that if the spring is too strong a strain will be imposed on the valve-operating mechanism and a hammering action produced which may cause deformation of the valve seat. Only pres- sure enough to insure that the operating mechanism will follow the cam is required. It is common practice to make the inlet and exhaust valve springs of the same tension when the valves are of the same size and both mechanically operated. This is done merely to simplify manufacture and not because it is necessary for the inlet valve spring to be as strong as the other. Piston and Rotary Valve Motors. Mention has been previously made of the interest obtaining in various forms of valves which permit more silent operation than the conventional poppet type. The main features of the Knight engine and its advantages have been considered, but a more complete description of the valve action may be timely. The sectional view through the cylinder at Fig. 82 shows the Knight sliding sleeves and their actuating means very clearly. The diagrams at Fig. 83 show graphically the sleeve movements and their relation to the crank shaft and piston travel. At A the piston has reached the top of the exhaust stroke and the exhaust port is barely open. The inlet port is just beginning to open. At B the piston is about two- thirds down on the inlet stroke and the inner sleeve has moved down, this bringing the two ports in alignment. This movement of the sleeve has closed off the exhaust port. At C the position of the sleeves at the end of the intake stroke is shown. The timer sleeve continues to go up, the outer sleeve is still moving down. Here we see the inlet port is almost closed; the exhaust port entirely so. D represents the position assumed by the sleeves at the end of the compression stroke, The Modern Gasoline Automobile 183 both ports are closed and the compressed charge is ready for ignition. At E the piston has covered about three-quarters of the power stroke Spark Plug Cranks Ova rating Sleeves Relief Cock Cylinder Head Outer Sleeve ner Sleeve Fig. 32. Section Through Cylinder of Knight Motor, Showing Important Parts of Valve Motion. and the exhaust port begins to open. Both sleeves are now traveling down. At F the piston has reached the bottom of the power stroke 184 The Modern Gasoline Automobile and the exhaust port is almost fully opened. At G the piston is mov- ing upward and the burned gas is being discharged through the fully opened exhaust port. At H the piston has started down on the intake stroke. The exhaust port is fully closed and the inlet port is just be- Fig. 83. Diagram Showing Relative Movement of Sleeves and Cam Shaft of Knight Type Motor. Note Port Opening at Various Piston Positions. Shaded Portions of Sleeves Represent Ports. ginning to open. The action may be summed up as follows : The inlet port begins to open when the lower edge of the opening of the outside sleeve which is moving down passes the top of the slot in the inner member also moving downwardly. The inlet port is closed when the The Modern Gasoline Automobile 185 lower edge of the slot in the inner sleeve which is moving up passes the top edge of the port in the outer sleeve which is also moving toward the top of the cylinder. The inlet opening extends over two hundred degrees of crank motion. The exhaust port is uncovered slightly when the lower edge of the port in the inner sleeve which is moving down passes the lower edge of the portion of the cylinder head which protrudes in the cylinder. When the top of the port in the outer sleeve traveling toward the bottom of the cylinder passes the lower edge of the slot in the cylinder wall the exhaust passage is closed. The exhaust opening extends over a period corresponding to about two hundred and forty degrees of crank motion. The Valveless Miesse Engine. The title given to this engine is hardly correct as it is not a valveless engine, but, as a glance at the illustration Fig. 84 will show, it is a combination of the single sleeve and piston valve forms. In the views presented, B is the single sleeve in which the port D is formed ; A is the inlet and E the exhaust open- ing. The part designated by C is termed the " distribution " piston. Both the inlet and exhaust passages open into and lead from the small cylinder in which the piston C reciprocates. This, as well as the sleeve B, derives its motion from the cam or valve shaft through connecting rods. But little explanation is necessary to describe the operation of the valves and their effect. At A the relative positions of the sleeve and piston valve during the induction stroke are shown. It will be seen that the port D in the sleeve coincides with the slot in the cylinder proper, and the piston valve C is in such position that while the mix- ture has free access from A to the cylinder the exhaust port E is cut off therefrom. At B the relative positions of the sleeve and piston valve during the explosion stroke are shown. The port D in the sleeve has moved up above the opening in the cylinder wall while the latter is there closed against any possible escape of gas by the cylin- drical head of the piston valve C. The position of the parts on the exhaust stroke are shown at C. The piston valve has risen still fur- ther, closing the induction passage A which leads the fresh gases to the cylinder and at the same time has made it possible for the exhaust products to be discharged beneath it through the opening E which is in connection with the exhaust manifold. The advantages claimed for this design are the use of a single 186 The Modern Gasoline Automobile sleeve, cooling of the sleeve cylinder ports and piston valve by the incoming mixture on the induction strike and the protection of the Fig. 84. Sectional Views Showing Action of Miesse Combination Sleeve and Piston Valve at Different Points in Cycle of Engine Operation. piston valve from contact with the exploded charge during the power stroke. It is said that the exhaust gases are discharged through the The Modern Gasoline Automobile 187 lower orifice rather than the upper one in order that no pressure be exerted upon the head of the piston and upon its connecting rod and crank pin bearings. By passing the exhaust gases which have con- siderable pressure between the upper and lower portions of the piston valve the latter is balanced during exhaust period by the products of the combustion under pressure. The valve shaft, which is the small auxiliary crank shaft reciprocating the sleeve and piston, is supported on five bearings and is driven by a silent chain connection from the main crank shaft. The Itala Rotary Valve Motor. A type of rotary valve which is said to be efficient is depicted at Fig. 85. This is used in the Itala engine and has features of merit. This motor does not differ much in appearance from the ordinary poppet valve type. The cylinders are cast in pairs with a projection at one side which acts as a cylinder for the valve. Provision is made for water circulation around this chamber and the valve is also formed in such a way that water may be circulated through it. But two valves are employed, one for each pair of cylinders, and these two members take the place of the eight valves used on the poppet engine. The valve driving shaft, which is placed similar to the conventional cam shaft, turns the vertical shaft to which the valves are attached by helical gears. There is but one port in each cylinder which provides the means of communication between the valves and combustion chamber, this alternately serving the purpose of inlet and exhaust port. The manifolds are on opposite sides of the engine. The gas enters the base of each valve chest and the inert products pass from the top of the valve chamber by a pecu- liar cored passage in the cylinder casting. The rotary valve is made of cast iron and carries a number of packing rings. Each valve has four vertical openings; two for the fresh gases, the others for the burned product. These openings are arranged so that there is one inlet and one exhaust port registering with the openings in the re- spective cylinders. The exhaust ports are wider than the inlet open- ings, because a longer period of opening is required for the exhaust. The views at Fig. 85 show the operation of the valve clearly. A depicts its position at the beginning of the intake stroke, the fresh gas entering from the bottom passes through the interior of the valve and into the combustion chamber. The smaller sectional views show a Fig. 85. Defining Action of Peculiar Rotary Valve Used in Latest Itala (Italian) Motor. 188 The Modern Gasoline Automobile 189 plan of the cylinder and valve chest. Referring to these it will be seen that the valve which is rotating in the direction of the arrow is just beginning to uncover the port in the cylinder. At B conditions dur- ing the compression stroke are shown. The port in the cylinder is Port Value Shaft Fig. 86. Partial Section of Reynolds Rotary Valve Motor Cylinder, Showing Method of Rotating Simple Disk Valve and Ports in Cylinder Head. closed by the solid wall of the valve. At C the position of the valve during the power stroke is shown. It will be observed that the open- in'.! in the cylinder is still closed by the valve wall. At D the condi- 190 The Modern Gasoline Automobile tions during the exhaust stroke are outlined. The valve has revolved so that the exhaust port therein is in communication with the exhaust pipe at the top of the cylinder and the port of the combustion cham- ber. This permits the inert gases to leave the cylinder freely. Careful study of the drawings will show that the gas flow is easy and that there are no sharp corners to impede the gases as they enter or leave the cylinders. The Reynolds Rotary Valve Motor. The Eeynolds motor, a sec-, tional view through one of its cylinders being shown at Fig. 86, has not been used to any extent in automobile service, but has proven thoroughly practical in marine applications. The valve consists of a flat disk seating directly against the top of the combustion chamber. It is turned by a shaft which extends through a boss on top of the cylinder head and which is driven direct from the crank shaft by gear- ing at half the motor speed. The valve has a port cut into it of the keystone shape, clearly shown in illustration, this registering suc- cessively with openings in the cylinder head. The valve mechanism is said to be very quiet, and, as will be seen at Fig. 87, the motor is a very compact design. A disadvantage is cited that the force of the explosion keeps the valve disk tight against the seat, this tending to cause considerable resistance to its motion. It is claimed that no difficulty is experienced from this source, and that an oil film is main- tained positively between the valve disk and its seat so that it turns with minimum friction. Other Rotary Valve Types. Various other forms employing rotary valves have been devised, and some of these which are said to have been used in a practical way are shown at Fig. 88. That at A is known as the Mead. This is a four-cylinder motor with two long cylindrical valves extending along opposite sides of the cylinders in close connection with the combustion chamber. These cylinders have ports cut through them at distances equal to the center line of the cylinders and are suitably spaced so that the ports in the cylinders are uncovered in proper succession. One of the drums serves to control the inlet ports ; the other regulates the exhaust openings. " The valves are driven at one-quarter crank-shaft speed by suitable gearing. The type shown at B is a French design which differs from the Eeynolds motor previously described only in the shape of the rotary The Modern Gasoline Automobile 191 valve member which is conical instead of flat. The parts are shown as follows : A is the rotary valve member ; B is the gas passage, and D is a port in the valve member. The small view presented below the vertical section is a plan showing the disposition of the ports. The Fig. 87. Part Section of Reynolds Rotary Valve Motor, Showing Practical Application of Ported Disk in Controlling Gas Passages. Note Compact Design of Cylinder Block and Two-Bearing, Four-Throw Crank Shaft. same lettering applies as above. If the cone (urns in the direct ion of the arrow, B is the exhaust port and C the intake port, while D repre- sents the opening in the valve. The form shown at C is a modification of that depicted at B. Two conical valves are used instead of one, 192 The Modern Gasoline Automobile Driving Gear Driven Gear Gas Passage Pig. 88. Unconventional Forms of Rotary Valve Motors Designed to Meet the Present Day Demand for Silent Valve Action. A Mead Motor Using Two Revolving Cylindrical Valves, One at Each Side of Cylinder. B Single Ported Cone Valve. C Application of Two Single Ported Cones, One Superposed. D Use of Distinct Valves, One for Inlet Port, the Other to Govern Exhaust Passage. The Modern Gasoline Automobile 193 these being turned in opposite directions by suitable gears. It is claimed that this gives a more rapid port opening than when a single valve is employed. Sometimes when two conical valve members are used they are placed side by side, as shown at D, one of these serving exclusively for the exhaust; the other for the inlet. The objection to this construction is that owing to the smaller size of the cone the ports are more limited in area than when a single valve member is employed. The Sphinx Ring Valve Motor. One of the designs which has been used successfully and which employs a ring valve in place of the usual poppet valves is called the Sphinx motor. It is claimed that all the advantages of the sliding sleeve types are obtained with much less com- plication. In this motor a split ring reciprocated by a bell crank serves to uncover the intake and exhaust ports. The construction of this member, as well as the actuating bell crank, return spring and ram shaft are clearly shown at Fig. 89. In the cylinder walls, and near the head, two annular chambers are provided, these forming the intake and exhaust ports. Within the cylinder is a split ring having sufficient face depth to cover both the intake and exhaust ports, but having the necessary reciprocating motion to allow it to uncover either one or the other of the ports as required to insure the admission of the fuel and the discharge of the spent gases. In its central position, shown at Fig. 89, B and C, the split ring covers the two ports, pro- viding a gas-tight chamber; on being moved down, as depicted at A, it uncovers the intake port and closes the exhaust, and on being raised, as outlined at D, it opens the exhaust and closes the intake. Being split, its extensibility assures gas-tightness, the degree of tightness being in proportion to the pressure in the cylinder, while leakage around the ports is impossible at any time. Its movement is slight, being less than one inch for a motor of 3.9-inch by 5.5-inch bore and stroke, and the intake port being above the ring, this latter is swept by the fresh, cool gases at every induction stroke and conse- quently maintained at a moderate temperature. This design particularly lends itself to an easily produced and clean monobloc casting, and has the further advantage of giving a compact combustion chamber without pockets and with unusually large valve area. On the ordinary type of motor with valves on one or both sides any increase in the valve diameter involves a propor- 194 The Modern Gasoline Automobile tional increase in the size of the pocket with a decrease of thermal efficiency. The split sliding ring, or sleeve, which in the " Sphinx " replaces the pair of poppet valves of the ordinary motor, and the costly concen- Value Return Spring Fig. 89. Part Section of Sphinx Valveless Motor in which Poppet Valves are Replaced by a Split Ring which Reciprocates in the Cylinder Head, Opening and Closing the Gas Ports as it Moves Up and Down. A Inlet Ports Open. B and C All Ports Closed. D Exhaust Ports Open. trie sleeves in motors of the sliding valve type, is shown in Fig. 89. It is a gray iron casting, having a face depth of one and a half inches for a motor of 3.9-inch by 5.5-inch bore and stroke, and provided with a hoi- The Modern Gasoline Automobile 195 ,ow spindle or bearing block for the rocker arm. As will be seen from the illustration, the depth of the ring is greater around the hollow spindle than at any other point, this increased depth being necessary to cover the port through which the rocker arm is passed from the outside to the inside of the cylinder. The face depth at this point is suffi- cient to assure the covering of this port whatever the position of the split ring; in other words, this slot in the cylinder wall is never uncovered. By means of a bell crank, the long arm of which operates in the socket of the ring valve, and an ordinary type of cam shaft the neces- sa ry reciprocating motion of the ring is obtained to allow the different phases of a four-cycle motor. One of the most valuable features of 'this motor is the large valve area obtainable without the complication attending the use of large diameter poppet valves and without the big pockets necessary with motors of the " L " or " T " type. The poppet valve spring must be of sufficient strength to correctly seat the valve at high motor speeds. If a weak spring is used it will not have time to return the valve to its seating before it will be again lifted by the cam and there is loss of power. The spring used on the " Sphinx " motor need only be strong enough to balance the weight of the split ring, for it is only responsible for its return and in no way jfor its proper seating. Further, as each upward movement of the ring is followed by the induction stroke of the motor, the work of the spring is relieved by the inrushing of the gases. In other words, the suction of the gas around the ring tends to draw it down, just as an automatic intake valve is drawn down on the suction stroke of the motor. The spring, then, need only be sufficiently strong to keep the roller in contact with the face of the cam, and as it is carried in an independent housing and not subjected to a high temperature, its life i- practically indefinite. Darracq Rotary Distributor Motor. In the Darracq power plant which is shown at Fig. 90, the gases enter through a rotary member of D section, which is placed horizontally along the side of the cylinder head and parallel with the crank shaft. This distributor is approxi- mately two-thirds the diameter of the cylinder and revolves on large annular ball bearings, one placed at each end. One member serves to control both intake and exhaust openings. This is accomplished by 196 The Modern Gasoline- Automobile providing the barrel-shaped chamber in which the valve revolves with three ports for each cylinder. One of these provides communication between the valve case and the combustion chamber, the others serve for intake and exhaust passages. Piston^ | Rotary Valve Fig. 90. Diagram Illustrating Action of Darracq (French) D Form Rotary Valve Motor. A Piston at Beginning of Induction Stroke. B Piston at Incep- tion of Compression Stroke. C Piston in Position for Receiving Explosion Impact. D Valve Position at Start of Exhaust Period. The Modern Gasoline Automobile 197 As the valve rotates the cylinder is placed in communication with either the intake or exhaust passages and the valve is driven by suit- able gearing at one-half the engine speed, as is the case with the con- ventional cam shaft. The various valve positions are clearly shown at Fig. 90. A corresponds to the suction stroke ; and the piston is shown starting to uncover the port leading from the valve chamber into the cylinder. The rotary valve is also uncovering the intake port. By the time the top of the piston reaches the bottom of the passage communi- < a ling between combustion and valve chambers, the inlet opening is uncovered and the gas rushes into the cylinder. At B it will be seen that the valve has closed the passage leading from the cylinder, and as the piston rises, the gas previously inspired is compressed. The posi- tion of the piston when it has reached the end of the compression stroke is shown at C. At this position the compressed charge is ignited. It will be noted that the piston covers the port leading into the valve chamber, and that the valve is thus protected from the direct heat of combustion. At D the position of the valve at the inception of the exhaust stroke is shown, and it is about to uncover the port lead- ing from the cylinder to the valve chamber and permit the exhaust gases to flow out through suitable openings. The heat evolved during ' the first intervals of the explosion, at which point the maximum tem- perature obtains, is kept from the valve and simplifies the problem of lubrication. It will be evident that with this construction a small por- tion of the inert gases are retained in the combustion chamber, but it is claimed by those favoring this construction that this does not con- stitute as serious defect in practice as theoretical considerations might indicate. The Hewitt Piston Valve Motor. A type of motor in which true piston valves are used successfully is shown in section at Fig. 91. This is the Hewitt, a pioneer form of English derivation. Two piston valves are provided fo % r each cylinder; one for the intake, the other to regulate the exhaust passage. They are placed adjacent to each other on the same side of the motor, and are inclined toward the top. A small crank shaft revolving at one-half the speed of the main crank shaft is employed to operate the piston. Each of these piston valves are simply smaller trunk pistons similar in type to those used in the cylinder proper, reciprocating in their distinct small water-cooled cyl- 198 The Modern Gasoline Automobile Main Connecting Hod inder. Piston rings of the conventional pattern are used to maintain a gas-tight joint, as is the case with the main piston. The fresh gas manifold is coupled to the side of one valve cylinder and the exhaust piping with the side of the other valve chamber. The timing of both intake and exhaust valves is such that they receive a portion of the explosive impulse, which drives them downward and tends to make them partially self - operating. When the explo- sion occurs, both valve pistons are at the top of their cylinders and receive part of the impact. On the compression stroke both pistons move up, the exhaust member moving ahead of the other. The piston valves are lubricated by splash just as the main piston chamber. These pistons have comparatively long stroke, about two-thirds that of the working piston. The various piston positions during the cycle of operation are clearly shown in diagrams at Fig. 92, the valves being shown at oppo- site sides of the cylinder to make their action clearer. At A the main piston is part way down on the intake stroke, and the inlet piston has uncovered the slots leading from the gas manifold to the combustion chamber. The exhaust is fully closed. At B the main piston is start- ing to go up on the compression stroke and both inlet and exhaust ports are fully closed by their respective pistons. At C the explosion has taken place and the three pistons are being driven down in the Crankshaft Value Shaft Fig. 91. Section of Hewitt Piston Valve, Motor Cylinder and Valve Chest. The Modern Gasoline Automobile 199 directions indicated by the arrow. At D the exhaust piston has un- covered the series of holes which provide communication between the combustion chamber and the manifold, while the inlet piston covers fully the slots it controls. It is claimed that this four-cylinder piston valve motor has superior torque to that obtained from a similar power plant using poppet valves. Fig. 92. Hewitt Piston Valve Motor Action Outlined Graphically. A Suction Stroke. B Compression. C Explosion. D Exhaust. Valve Timing. It is in valve timing that the greatest difference of opinion prevails among engineers and it is rare that one will see the same formula in different motors. It is true that the same timing could not be used with motors of different construction, as there are many factors which determine the amount of lead to be given to the 200 The Modern Gasoline Automobile valves. The most important of these is the relative size of the valve to the cylinder bore, the speed of rotation it is desired to obtain, the fuel efficiency, the location of the valves, and other factors too numerous to mention. Most of the readers should be familiar with the cycle of operation of the internal combustion motor of the four-stroke type, and it seems unnecessary to go into detail except to present a review. The first stroke of the piston is one in which a charge of gas is taken into the motor; the second stroke which is in reverse direction to the first is a compression stroke, at the end of which the spark takes place, ex- ploding the charge and driving the piston down on the third or expan- sion stroke, which is in the same direction as the intake stroke, and finally, after the piston has nearly reached the end of this stroke, another valve opens to allow the burned gases to escape, and remains open until the piston has reached the end of the fourth stroke and is in a position to begin the series over again. The ends of the strokes are reached when the piston comes to a stop at either top or bottom of the cylinder and reverses its motion. That point is known as a center and there are two for each cylinder, top and bottom centers, re- spectively. All circles may be divided into 360 parts, each of which is known as a degree, and in turn each of these degrees may be again divided into minutes and seconds, though we need not concern ourselves with any- thing less than the degree. Each stroke of the piston represents 180 degrees travel of the crank, because two strokes represent one complete revolution or three hundred and sixty degrees. The top and bottom centers are therefore separated by 180 degrees. Theoretically each phase of a four-cycle engine begins and ends at a center, though in actual practice the inertia or movement of the gases makes it neces- sary to allow a lead or lag to the valve, as the case may be. If a valve opens before a center, the distance is called " lead " ; if it closes after a center, this distance is known as " lag." The profile of the cams ordinarily used to open or close the valves represents a consider- able time in relation to the 180 degrees of the crank-shaft travel, and the area of the passages through which the gases are admitted or exhausted is quite small owing to the necessity of having to open or close the valves at stated times; therefore, to open an ade- The Modern Gasoline Automobile 201 quately large passage for the gases it is necessary to open the valves earlier and close them later than at centers. That advancing the opening of the exhaust valve was of value was discovered on the early motors and is explained by the necessity of releasing a large amount of gas, the volume of which has been greatly raised by the heat of combustion. When the inlet valves were mechan- ic all v operated it was found that allowing them to lag at closing en- abled the inspiration of a greater volume of gas. Disregarding the inertia or flow of the gases, opening the exhaust at center would enable one to obtain full value of the expanding gases the entire length of the piston stroke, and it would not be necessary to keep the valve open after the top center, as the reverse stroke would produce a suction effect which might draw some of the inert charge back into the cylin- der. On the other hand, giving full consideration to the inertia of the gas, opening the valve before center is reached will provide for quick expulsion of the gases, which have sufficient velocity at the end of the stroke, so that if the valve is allowed to remain open a little longer, the amount of lag varying with the opinions of the designer, the cylinder is cleared in a more thorough manner. Blowing Back. When the factor of retarded opening is considered without reckoning the inertia of the gases it would appear that, if the valve were allowed to remain open after center had passed say on the closing of the inlet, the piston having reversed its motion would have the effect of expelling part of the fresh charge through the still open valve as it passed inward at its compression stroke. This effect is called blowing back and is often noted with motors where the valve settings are not absolutely correct, or where the valve springs or seats are defective and prevent proper closing. This factor is not of as much import as might appear, as on closer consideration it will be seen that the movement of the piston as the crank reaches either end of the stroke is less per degree of angular movement than it is when the angle of the connecting rod is greater. Then again a certain length of time is required for the reversal of motion of the piston, during which time the crank is in motion but the piston practically at a standstill. If the valves are allowed to remain open during this period, the passage of the gas in or out of tin- cylinder will be by its own momentum. 202 The Modern Gasoline Automobile Lead Gives Exhaust Valve. The faster a motor turns, all other things being equal, the greater the amount of lead or advance it is necessary to give the opening of the exhaust valve. It is self-evident truth that if the speed of a motor is doubled, it travels twice as many degrees in the time necessary to lower the pressure. As most designers are cognizant of this fact the valves are proportioned accordingly. It is well to consider in this respect that the cam profile has much to do with the manner in which the valve is opened, that is, the lift may be abrupt and the gas allowed to escape in a body, or the opening may be gradual, the gas issuing from the cylinder in thin streams-. An analogy may be made with the opening of any bottle which contains liquid highly carbonated. If the cork is removed suddenly the gas escapes with a loud pop, but on the other hand, if the bottle is un- corked gradually, the gas escapes from the receptacle in thin streams around the cork, and passage of the gases to the air is accomplished without noise. While the second plan is not harsh, it is slower than the former, as must be evident. Exhaust Closing, Inlet Opening. A- point which has been much discussed by engineers is the proper relation of the closing of the ex- haust valve and the opening of the inlet. Theoretically they should succeed each other, the exhaust closing at upper dead center and the inlet opening immediately afterward. The reason why a certain amount of lag is given the exhaust closing in practice is that the piston cannot drive the gases out of the cylinder unless they are com- pressed to a degree in excess of that existing in the manifold or pas- sages, and while toward the end of the stroke this pressure may be feeble, it is nevertheless indispensable. At the end of the piston's stroke, as marked by the upper dead center, this compression still exists, no matter how little it may be, so that if the exhaust valve is closed and the inlet opened immediately afterward, the pressure which exists in the cylinder may retard the entrance of the fresh gas and a certain por- tion of the inert gas may penetrate into the manifold. As the piston im- mediately begins to aspirate this may not be serious, but as these gases are drawn back into the cylinder the fresh charge will be diluted and weakened in value. If the spark plug is in a pocket the points may be surrounded by this weak gas, and the explosion will not be nearly as energetic as when the ignition spark takes place in pure mixture. The Modern Gasoline Automobile 203 It is a well-known fact that the exhaust valve should close after dead center and that a certain amount of lag should be given to open- ing of the inlet. The lag given the closing of the exhaust valve should not be as great as that given the closing of the inlet valve. Assuming thai the excess pressure of the exhaust will equal the depression during a-pi ration, the time necessary to complete the emptying of the cylinder will be proportional to the volume of the gas within it. At the end of the suction stroke the volume of gas contained in the cylinder is equal to the cylindrical volume plus the space of the combustion cham- ber. At the end of the exhaust stroke the volume is but that of the dead space, and from one-third to one-fifth its volume before compres- sion. While it is natural to assume that this excess of burned gas will escape faster than the fresh gas will enter the cylinder, it will be seen that if the inlet valve were allowed to lag twenty degrees, the exhaust valve lag need not be more than five degrees, providing that the ca- pacity of the combustion chamber was such that the gases occupied one-quarter of their former volume. It is evident that no absolute rule can be given, as back pressure will vary with the design of the valve passages, the manifolds, and the roust ruction of the muffler. The more direct the opening, the sooner il ie valve can be closed and the better the cylinder cleared. Ten de- grees represent an appreciable angle of the crank and the time re- quired for the crank to cover this angular motion is not inconsiderable and an important quantity of the exhaust may escape, but the piston is still very close to the dead center after the distance has been covered. Before the inlet valve opens there should be a certain depression in the cylinder, and considerable lag may be allowed before the de- pression is appreciable. So far as the volume of fresh gas introduced during the admission stroke is concerned, this is determined by the displacement of the piston between the point where the inlet valve opens and the point of closing, assuming that sufficient gas has been in- pi red so that an equilibrium of pressure has been established be- tween the interior of the cylinder and the outer air. The point of inlet opening varies with different motors. It would appear that a fair amount of lag would be fifteen degrees past top center for the inlet opening, as a certain depression will exist in the cylinder, assum- ing that the exhaust valve has closed five or ten degrees after center, 204 The Modern Gasoline Automobile and at the same time the piston has not gone down far enough on it- stroke to materially decrease the amount of gas which will be taken into the cylinder. Closing the Inlet Valve. As is the case with the other points of opening and closing, there is a wide diversity of practice as relates to closing the inlet valve. Some of the designers close this exactly at bottom center, but this practice cannot be commended, as there is a considerable portion of time, at least ten or fifteen degrees angular motion of the crank, before the piston will commence to travel any extent on its compression stroke. The gases rushing into the cylinder have considerable velocity, and unless an equilibrium is obtained between the pressure inside and that of the atmosphere outside, they will continue to rush into the cylinder even after the piston ceases to exert any suction effect. For this reason, if the valve is closed exactly on center, a full charge may not be inspired into the cylinder, though if the time of closing is delayed, this momentum or inertia of the gas will be enough to insure that a maximum charge is taken into the cylinder. The writer considers that nothing will be gained if the valve is allowed to remain open longer than twenty degrees, and an analysis of practice in this respect would seem to confirm this opinion. From that point in the crank movement the piston travel increases and the compressive effect is appreciable, and it would appear that a considerable propor- tion of the charge might be exhausted into the manifold and carbu- retor if the valve were allowed to remain open beyond a point cor- responding to twenty degrees angular movement of the crank. Time of Ignition. In this country engineers unite in providing a variable time of ignition, though abroad some difference of opinion is noted on this point. The practice of advancing the time of ignition, when affected electrically, was severely condemned by early makers, these maintaining that it was necessary because of insufficient heat and volume of the spark, and it was thought that advancing ignition was injurious. The engineers of to-day appreciate the fact that the heat of the electric spark, especially when from a mechanical generator of electrical energy, is the only means by which we can obtain prac- tically instantaneous explosion, as required by the operation of motors at high speeds, and for the combustion of large volumes of gas. The Modern Gasoline Automobile 205 It is apparent that a motor with a fixed point of ignition is not as desirable, in every way, as one in which the ignition can be advanced to best meet different requirements, and the writer does not readily perceive any advantage outside of simplicity of control in establishing a fixed point of ignition. In fact, there seems to be some difference of opinion among those designers who favor fixed ignition, and in one case this is located forty-three degrees ahead of center, and in another motor the point is fixed at twenty degrees, so that it may In 1 said that this will vary as much as one hundred per cent in various forms. This point will vary with different methods of ignition, as well as the location of the spark plug or igniter. The writer favors a variable point of ignition, as this offers advantages which cannot be obtained with fixed ignition, and enables one to best gauge the require- ments of the time of firing the charge by conditions of operation from time to time. The range may be as desired, varying from a point after center for starting to one forty-five degrees advanced for maxi- mum speed. Then again, flexibility of control is greatly increased when spark time may be varied to suit requirements. It is obvious by consideration of the foregoing that there can be no arbitrary rules established for timing, because of the many condi- tions which determine the best times for opening and closing the valves. It is customary to try various settings when a new motor is designed until the most satisfactory points are determined, and the ^citing which will be very suitable for one motor is not always right for one of different design. A series of valve-timing diagrams are presented at Fig. 93, these showing the timing employed on four different engines of about the same size. In that outlined at A the inlet valve begins to open eight degrees after center and closes exactly on the bottom center. The exhaust opens thirty degrees before bottom center and closes five ii'iiTres after top center. This motor employs large valves placed in the head and does not need much lead of the exhaust opening. In the diagram shown at B the inlet valve has a lag of fourteen degrees on the opening and closes six degrees after bottom center. The exhaust valve opens forty-one degrees before bottom center. The timing method outlined at C gives a greater lead to the ex- haust than any of the others shown. The exhaust valve starting 206 The Modern Gasoline Automobile to open forty-seven degrees before center and closing twelve degrees after top center. The inlet valve begins to open nine degrees after top center and lags seventeen degrees after bottom center. It will be Fig. 93. Diagrams Showing Different Valve Timing Methods. noticed that the exhaust valve is just closing while the inlet is open- ing, the closing of one member being coincident with the opening of The Modern Gasoline Automobile 207 the other. This is not very often followed, because there is danger of the admixture of gases should anything interfere with prompt valve action. The diagram shown at D does not differ very much from that shown at B, except in the lag of the inlet valve. This opens at thir- teen degrees after top center and does not close until twenty-two de- ;rivcs after bottom center. The exhaust valve opens thirty-nine de- grees before bottom center and closes ten degrees after top center. It will be seen that at A there is a lapse of three degrees between exhaust valve closing and inlet valve opening. At B the lapse is two degrees. At C the timing arrangement is such that there is no lapse between exhaust closing and inlet opening. Practically as soon as the exhaust valve is closed fully the inlet valve has opened materially. At D the la !>.<< between exhaust valve closing and inlet opening is three degrees. These methods of timing may be considered representative, though almost every designer follows his own preferences. Sometimes con- siderable experimenting is necessary before the point is reached where the motor runs with the maximum power and without noise. The diagram at Fig. 94 shows clearly the method utilized in mark- ing the fly wheel of a typical four-cylinder engine so that the valves may be properly timed without following piston or crank-shaft move- ment directly. The fly wheel, which is 15^4 inches in circumference, has been marked off as indicated. As this is a four-cylinder engine, the marks on the fly wheel enable one to time all cylinders, as one of two will fire when one mark corresponding to upper center coincides with the fixed indicating device on the center line of the crank case. The others explode in turn when the mark indicating the lower center registers with the trammel point, as the little indicating device on the crank case is called. When the diameter of a fly wheel is 15^4 inches, <;> inches measured from one of the center lines indicate the crank- pin travel of fifteen degrees. The lag of inlet closing which in this motor is thirty-three degrees is represented by a distance of 4.536 inches on the circumference of the fly wheel. The exhaust valve lead which is fifty-three degrees and thirty minutes is determined by meas- uring 7.353 inches ahead of the center lines. The point where the exhaust valve closes which is twelve degrees after center is represented by a distance of 1.649 inches on the flv wheel. It will be noted that in 208 The Modern Gasoline Automobile this case there is a lapse of three degrees between the exhaust closing and the inlet opening. The exhaust valve is kept open considerably longer than is usually the case, as it lags thirty-three degrees after the piston is started to go up on its compression stroke. The exhaust Inlet Opens 15 =2. 062 Late on Circumference. Inlet Closes 33 =4.536" Late on Circumference. Exhaust Opens 5330'=7.3 Early on. Circumference. Exhaust Closes 12=L649 Late on Circumference. Motor Fires 1-3-4-2 HUDSON Fig. 94. Diagram Showing Method of Marking Fly-wheel Circumference to Obtain Proper Timing of Typical Four-Cylinder Motor. valve opens much earlier, i. e., it is given a greater lead than an analy- sis of common practice shows to be desirable. The exhaust valve is opened considerably longer than is usually the case, as the average lead given to exhaust is about forty degrees. In timing a motor from the marks on the fly-wheel rim it is neces- sary to regulate the valves of but one cylinder at a time. Assuming that the fly wheel is revolving in the direction of the arrow and that the firing order of the cylinders is 1-3-4-2 the operation of timing would be carried on as follows : The fly wheel would be revolved until The Modern Gasoline Automobile 209 the line marked " Exhaust opens 1 and 4 " registered with the trammel on the motor bed. At this point the exhaust valve of either cylinder Xo. 1 or Xo. 4 should begin to open. This can be easily determined by noting which of these cylinders holds the compressed charge ready for ignition when the fly wheel is in the position shown in drawing. Assuming that the spark has occurred in cylinder Xo. 1, then when the fly wheel is turned from the position shown in the sketch to that in which the line marked " Exhaust opens 1 to 4 " coincides with the trammel point, the valve plunger under the exhaust valve of cylinder 1 should be adjusted in such a way that there is no clearance ^tween it and the valve stem. Further movement of the wheel in same direction should produce a lift of the exhaust valve. The ]y wheel is turned about two hundred and forty-five degrees or about three-quarters of a revolution ; then the line marked " Exhaust closes 1 and 4 " will register with the trammel point. At this period the valve plunger and the valve stem should separate and a certain amount clearance obtained between them. The next cylinder to time would No. 3. The fly wheel is rotated until mark " Exhaust opens 2 and ' comes in line with the trammel. At this point the exhaust valve of rlinder Xo. 3 should be just about opening. The closing is deter- icd by rotating the fly wheel until the line " Exhaust closes 2 and 3 " comes under the trammel. This operation is carried on with all the cylinders, it being well to remember that but one cylinder is working at a time and that a half revolution of the fly wheel corresponds to a full working stroke of all the cylinders, and that while one is exhausting, the others are respect- ively taking in a new charge, compressing and exploding. For in- stance, if cylinder X T o. 1 has just completed its power stroke the piston in cylinder Xo. 3 has reached the point where the gas may be ignited to advantage. The piston of cylinder Xo. 4, which is next to fire, is at the bottom of its stroke and will have inspired a charge, while cylinder Xo. 2, which is the last to fire, will have just finished expelling a charge of burned gas, and will be starting the intake stroke. Unconventional Poppet Valve Arrangement. While practically all motors of the L-head form have the valves arranged in the same plane, i. e., one behind the other, efforts have been made to arrange the valves in a different manner in the Julian motor, shown at Fig. 210 The Modern Gasoline Automobile 94. In this the valves are placed side by side, both being approxi- mately in a line with the center line of the cylinder. It is contended by the designer that this method of placing makes for a better com- Corer For Top of Fig. 94a. Sectional View of the Julian Engine which Employs a Peculiar Valve Arrangement. bustion-chamber form than the usual system, though it is difficult to see how this claim is justified, because while the pocket is not as long as those in which the valves are placed one to each side of the cylinder center line, it is wider and probably has the same amount The Modern Gasoline Automobile 211 of space that would be present in the conventional form. The inlet valve is inclined and is the one immediately under the spark plug, while the exhaust valve or outer one is placed vertically, as in con- ventional construction. The inlet and exhaust manifolds are cast integral with the cylinder block and the arrangement permits of ample water cooling of the exhaust manifold. This form of engine has not been generally applied and is presented simply to show one of many possible valve arrangements. The Fischer Slide-Valve Motor. The Fischer slide-valve motor employs a very peculiar form of reciprocating member to control the flow of gases in and out of the cylinder. These valves, which are c-rcx-cnt shape in cross section, operate in suitably formed recesses in the opposite sides of the cylinder bore, which is not a circle, as in the usual construction, but an irregular figure composed of approxi- mately two semi-circular parts connected by two crescent-shaped parts. The slide valves occupy approximately 69 degrees of the cylinder-wall circumference. They are of cast iron and extend the entire length of the cylinder and approximately two inches below it. At their lower extremities they carry slots for the engagement of the operating bell-crank mechanism worked by box cams, mounted on shafts which are driven by silent chains from the crank shafts. The sleeves are reciprocated by bell cranks, one end being attached to the sleeve, the other arm carrying a roller which fits the depression in the cam. This form of cam insures positive movement in both directions and makes it possible to entirely dispense with the use of springs. The slides are provided with suitable slots or ports which register with openings in the cylinder walls communicating with the inlet and exhaust passages respectively. The arrangement of the cams is such that the reciprocation of the sleeves gives the following timing: The inlet has a lag of 11 degrees after the upper dead center and closes 71 degrees after lower dead center. The exhaust opens 63 degrees before lower dead center and closes 19.75 degrees late, or after the piston reaches the top of its exhaust stroke. This means that the intake and exhaust overlap approximately 8 degrees, which is claimed to give additional power. Owing to the peculiar box-cam construction the slide valves are not in motion during the compression and power 212 The Modern Gasoline Automobile Fig. 94b. Part Sectional View of the Fischer Slide-Valve Motor. The Modern Gasoline Automobile 213 strokes. The Fischer motor is a four-cylinder monobloc type with a bore of 3 T ^ inches and a stroke of 4J inches. The pistons recipro- cate up and down in a cylinder which is composed of two fixed por- tions and two movable sleeves. After the sleeves are in place the interior of the cylinder bore is a true circle and the piston has an even bearing on all portions of the cylinder wall and sleeves. The general features of construction and the arrangement of the sliding sleeves and their actuating mechanism are clearly shown at Fig. 946. CHAPTEE IV Considering Pistons, Piston Rings, Connecting Rods, Crank Shafts, the Fly Wheel, and Engine Base Construction Typical Two- and Four-Cycle Power Plants Described. Constructional Details of Pistons. The piston is one of the most important parts of the gasoline motor inasmuch as it is the recipro- cating member that receives the impact of the explosion and which transforms the power obtained by the combustion of gas to mechan- ical motion by means of the connecting rod to which it is attached. The piston is one of the simplest elements of the motor, and it is one component which does not vary much in form in different types of motors. The piston is a cylindrical member provided with a series of grooves in which packing rings are placed on the outside and two bosses which serve to hold the wrist pin in its interior. It is usually made of cast iron, though in some motors where extreme lightness is desired, such as those used for aeronautic work, it may be made of steel. The use of the more resisting material enables the engineer to use lighter sections where it is important that the weight of this mem- ber be kept as low as possible consistent with strength. A number of piston types are shown at Pig. 95. That at A has a round top and is provided with four split packing rings and two oil grooves. A piston of this type is generally 'employed in motors where the combustion chamber is large and where it is desired to obtain a higher degree of compression than would be possible with a flat top piston. This construction is also stronger because of the arched piston top. The most common form of piston is that shown at B, and it differs from that previously described only in that it has a flat top. The piston outlined in section at C is a type used on some of the sleeve-valve motors of the Knight pattern, and has a concave head instead of the convex form shown at A. The design shown at D in side and plan views is the conventional form employed in two- cycle engines. The deflector plate on the top of the cylinder is cast 214 The Modern Gasoline Automobile 215 integral and is utilized to prevent the incoming fresh gases from flow- ing directly over the piston top and out of the exhaust port which is usually opposite the inlet opening. On those types of two-cycle en- gines where a two-diameter cylinder is employed, the piston shown at E is used. This is known as a " differential piston," and has an en- larged portion at its lower end which fits the pumping cylinder. The Fig. 95. Forms of Pistons Commonly Employed in Gasoline Engines. A Dome Head Piston with Three Packing Rings. B Flat Top Form Almost Universally Used. C Concave Piston Utilized in Knight Motors and Some Having Overhead Valves. D Two-Cycle Engine Member with Deflector Plate Cast Integrally. E Differential of Two-Diameter Piston Used in Some Engines Operating on Two-Cycle Principle. usual form of deflector plate is provided at the top of the piston and one may consider it as two pistons in one. One of the important conditions in piston design is the method of securing the wrist pin which is used to connect the piston to the upper end of the connecting rod. Various methods have been devised to keep the pin in place, the most common of these being shown at Fig. 216 The Modern Gasoline Automobile 96. The wrist pin should be retained by some positive means which is not liable to become loose under the vibratory stresses which obtain at this point. If the wrist pin was free to move it would work out of the bosses enough so that the end would bear against the cylinder wall. As it is usually made of steel, which is a harder material than cast iron used in cylinder construction, the rubbing action would tend to cut a groove in the cylinder wall which would make for loss of power because it would permit escape of gas. The wrist pin member is a simple cylindrical element that fits the bosses closely, and it may be either hollow or solid stock. The method of retention shown at A is. the simplest and consists of a set screw having a projecting portion passing into the wrist pin and holding it in place. The screw is kept from turning or loosening by means of a check nut. The method outlined at B is similar to that shown at A, except that the wrist pin is solid and the point of the set screw engages an annular groove turned in the pin for its recep- tion. A very positive method is shown at C. Here the retention screws pass into the wrist pin and are then locked by a piece of steel wire which passes through suitable holes in the ends. The method outlined at D is sometimes employed, and it varies from that shown at C only in that the locking wire, which is made of spring steel, is passed through the heads of the locking screws. Some designers ma- chine a large groove around the piston at such a point that when the wrist pin is put in place a large packing ring may be sprung in the groove and hold the wrist pin in place. The system shown at F is not so widely used as the simpler meth- ods, because it is more costly and does not offer any greater security when the parts are new than the simple lock shown at A. In this a hollow wrist pin is used, having a tapered thread cut at each end. The wrist pin is slotted at three or four points, for a distance equal to the length of the boss, and when taper expansion plugs are screwed in place the ends of the wrist pin are expanded against the bosses. This method has the advantage of providing a certain degree of adjustment if the wrist pin should loosen up after it had been in use for some time. The taper plugs would be screwed in deeper and the ends of the wrist pin expanded proportionately to take up the loss motion. The method shown at G is an ingenious one, One of the piston bosses is provided 217 218 The Modern Gasoline Automobile with a projection which is drilled out to receive a plunger. The wrist pin is provided with a hole of sufficient size to receive the plunger, which is kept in place by means of a spring in back of it. This makes a very positive lock and one that can be easily loosened when it is desired to remove the wrist pin. To unlock, a piece of fine rod is thrust into the hole at the bottom of the boss and pushes the plunger back against the spring until the wrist pin can be pushed out of the piston. Some engineers think it advisable to oscillate the wrist pin in the piston bosses, instead of in the connecting rod small end. It is argued that this construction gives more bearing surface at the wrist pin and also provides for more strength because of the longer bosses that can be used. When this system is followed the piston pin is held in place by locking it to the connecting rod by some means. At H the simplest method is outlined. This consisted of driving a taper pin through both rod and wrist pin and then preventing it from back- ing out by putting a split cotter through the small end of the tapered locking pin. Another method, which is depicted at I, consists of clamping the wrist pin by means of a suitable bolt which brings the slit connecting rod end together as shown. Piston Ring Construction. As all pistons must be free to move up and down in the cylinder with minimum friction, they must be less in diameter than the bore of the cylinder. The amount of freedom or clearance provided varies with the construction of the engine, but it is usual to provide from .005 to .010 of an inch to compensate for the expansion of the piston due to heat and also to leave sufficient clearance for the introduction of lubricant between the working sur- faces. Obviously, if the piston were not provided with packing rings, this amount of clearance would enable a portion of the gases evolved when the charge is exploded to escape by it into the engine crank case. The packing members or piston rings, as they are called, are split rings of cast iron, which are sprung into suitable grooves machined on the exterior of the piston, three or four of these being the usual number supplied. These have sufficient elasticity so that they bear tightly against the cylinder wall and thus make a gas-tight joint. Owing to the limited amount of surface in contact with the cylinder wall and the elasticity of the split rings the amount of friction resulting from the The Modern Gasoline Automobile 219 contact of properly fitted rings and the cylinder is not of enough mo- ment to cause any damage and piston is free to slide up and down in the cylinder bore. These rings are made in two forms, as outlined at Fig. 97. The design shown at A is termed a "concentric ring," because the inner circle is concentric with the outer one and the ring is of uniform Fig. 97. Types of Piston Rings and Ring Joints. A Concentric Ring. B Ec- centrically Machined Form. C Lap Joint Ring. D Butt Joint, Seldom Used. E Diagonal Cut Member, a Popular Form. thickness at all points. The ring shown at B is called an " eccentric ring," and it is thicker at one part than the other. It has theoretical ;i< I \antages in that it will make a tighter joint than the other form, as it is claimed its expansion due to heat is more uniform. The piston rings must be split in order that they may be sprung in place in the grooves, and also to insure that they will have sufficient elasticity to take the form of the cylinder at the different points in their travel. If the cylinder bore varies by small amounts the rings will spring out at the points where the bore is larger than standard, and spring in at those portions where it is smaller than standard. It is important that the joint should be as nearly gas-tight as pos- sible, because if it were not a portion of the gases would escape through the slots in the piston rings. The joint shown at C is termed a " lap joint," because the ends of the ring are cut in such a manner that they overlap. This is the approved joint. The butt joint shown at D is seldom used and is a very poor form, the only advantage being its cheapness. The diagonal cut shown at E is a compromise between the very good form shown at C and the poor joint depicted at D. It 220 The Modern Gasoline Automobile is also widely used, though most constructors prefer the lap joint, because it does not permit the leakage of gas as much as the other two types. The illustration at Fig. 98 shows a typical flat top piston, provided with diagonal cut concentric packing rings. One of these members is Fig. 98. Showing Flat-Top Piston Provided with Four Concentric Rings, One of the Packing Members and the Wrist Pia with its Bushing. shown on top of the piston and the wrist pin and the bushing which fits it and which is forced into the small end of the connecting are placed at one side. In some cases the piston rings are pinned ii place in their grooves so that they cannot move around until they ai all in such a position that the slots will come in line. In others, it believed that they are left free to turn that they will wear in The Modern Gasoline Automobile 221 and conform to the bore of the cylinder better than if they are kept from turning. When the rings are pinned they usually have the diag- onal cut, while those that are left free are usually provided with the lap joint. Connecting Rod Forms. The connecting rod is the simple member that joins the piston to the crank shaft and which transmits the Fig. 99. Typical Connecting Rod and its Wrist Pin. Lower Bearing Cap Held by Four Bolts. White Metal Boxes in Cast Bronze Rod. power imparted to the piston by the explosion so that it may be use- fully applied. It transforms the reciprocating movement of the piston to a rotary motion at the crank shaft. A typical connecting rod and its wrist pin are shown at Fig. 99. It will be seen that it has two bearings, one at either end. The small end is bored out to receive the wrist pin which joins it to the piston, while the large end has a hole of sufficient size to go on the crank pin. . The connecting rod is usually a steel forging, though it is sometimes made a steel or high tensile strength bronze casting. In all cases it is desirable to have softer metals than the crank shaft and wrist pin at the bearing point, and for this reason the connecting rod is usually provided with bush- ings of anti-friction or white metal at the lower end, and bronze at the upper. The upper end of the connecting rod may be one piece, because the wrist pin can be introduced after it is in place between the bosses of the piston. The lower bearing must be made in two parts in most cases, because the crank shaft cannot be passed through the bearing owing to its irregular form. 222 The Modern Gasoline Automobile Some of the various designs of connecting rods that have been used are shown at Fig. 100. That at A is a simple form often em- ployed in single-cylinder motors, having built-up crank shafts. Both ends of the connecting rod are bushed with a one-piece bearing, as it can be assembled in place before the crank-shaft assembly is built up. A built-up crank shaft such as this type of connecting rod would be used with is shown at Fig. 106. The pattern shown at B is one that has been used to some extent on heavy work, and is known as the " marine type." It is made in three pieces, the main portion being a steel forging having a flanged lower end to which the bronze boxes are secured by bolts. The modified marine type depicted at C is the form that has received the widest application in automobile construc- tion. It consists of two pieces, the main member being a steel drop forging having the wrist-pin bearing and the upper crank-pin bearing formed integral, while the lower crank-pin bearing member is a sepa- rate forging secured to the connecting rod by bolts. In this construction bushings of anti-friction metal are used at the lower end, and a bronze bushing is forced into the upper- or wrist-pin end. The rod shown at D has also been widely used. It is similar in construction to the form shown at C, except that the upper end is split in order to permit of a degree of adjustment of the wrist-pin bushing, and the lower bearing cap is a hinged member which is retained by one bolt instead of two. When it is desired to assemble it on the crank shaft the lower cap is swung to one side and brought back into place when the con- necting rod has been properly located. Sometimes the lower bearing member is split diagonally instead of horizontally, such a construction being outlined at E. In a number of instances, instead of plain bushed bearings anti- friction forms using ball or rollers have been used at the lower end. A ball-bearing connecting rod is shown at F. The big end may be made in one piece, because if it is possible to get the ball bearing on the crank pins it will be easy to put the connecting rod in place. Ball bearings are not used very often on connecting rod big ends because of difficulty of installation, though when applied properly they give satisfactory service and reduce friction to a mini- mum. One of the advantages of the ball bearing is that it requires no adjustment, whereas the plain bushings depicted in the other con- 223 224 The Modern Gasoline Automobile necting rods must be taken up from time to time to compensate for wear. This can be done in forms shown at B, C, D, and E by bringing the lower bearing caps closer to the upper one and scraping out the Fig. 101. Crank Shaft, Piston and Connecting Rod Assembly Used in Reo Motors. brasses to fit the shaft. A number of liners or shims of thin brass or copper stock varying from .002 inch to .005 inch are sometimes inter- posed between the halves of the bearings when it is first fitted to the crank pin. As the brasses wear the shims may be removed and the portions of the bearings brought close enough together to take up any lost motion that may exist. The various structural shapes in which connecting rods are formed are shown in section at G. Of these the I section is most common, because it is strong and a very easy shape to form by the drop-forging process. Where extreme lightness is desired, as in small high-speed motors used for cycle propulsion, the section shown at the extreme left is often used. If the rod is a cast member the cross, hollow cylin- der, or TJ sections are sometimes used. If the sections shown at the right are employed, advantage is often taken of the opportunity for passing lubricant through the center of the hollow round section on Tlic Modern Gasoline Automobile 225 vertical motors or at the bottom of the 17 section, which would be used on a horizontal cylinder power plant. Cam-Shaft Forms. Piston and connecting rod types having been described, the next component of importance to receive attention should be the crank shaft. These vary in form according to the de- signs of the motor and number of cylinders employed. A typical crank shaft, piston, and connecting rod assembly which forms part of the Eco motor is shown at Fig. 101, and the parts are so clearly shown that no description is necessary. Before going extensively into the subject of crank-shaft construc- tion it will be well to consider cam-shaft design, which is properly a part of the valve system and which should be considered in connection Fig. 102. Some of the Components of Corbin " 40 " Motor. A Piston and Con- necting Rod Assembly. B Inlet and Exhaust Cam Shafts. C Twin- Cylinder Casting. with the other elements which have to do directly with cylinder con- struction. Cam shafts are usually simple members carried at the base of the cylinder in the engine case by suitable bearings and having the cams employed to lift the valves attached at intervals. A typical cam- shaft design is shown at Fig. 102 in connection with one of the twin- cylinder castings and the piston and connecting rod assembly of the 226 The Modern Gasoline Automobile Corbin " 40 " motor. Two main methods of cam-shaft construction are followed that in which the cams are separate members, keyed and pinned to the shaft, and the other where the cams are formed integral. The cam shafts shown at Fig. 102 are of the former type, as the cams are machined separately and held in place by means of keys and *=* Fig. 103. Typical Cam Shaft with Valve Lifting Cams and Gears to Operate Auxiliary Devices Forged Integrally. taper pins. The small gears used to drive some of the accessory mech- anism, such as the oil pump, timer, etc., are also separately formed and pinned to the cam shaft. At Fig. 103 the other method of cam- shaft construction is outlined. In this case not only the cams but also the gears used in driving the auxiliary shafts are forged integral. This is a more expensive construction than that shown at Fig. 102, because of the high initial cost of forging dies as well as the greater expense of machining. It has the advantage over the other form in which the cams are keyed in place in that it is stronger, and as the cams are a part of the shaft they can never become loose, as might be possible where they are separately formed and assembled on a simple shaft. As an example of an auxiliary shaft carried at the side of the motor and driven from the cam shaft the assembly at Fig. 104 is given. This is driven from one of the small gears shown at Fig. 103 and carries the ignition timer at the upper end and drives the oil pump through a spring coupling at its lower end. Crank-shaft Types Outlined. The importance of the crank shaft has been previously considered, and some of its forms have been shown in views of the motors presented in earlier portions of this work. The crank shaft is one of the parts subjected to the greatest strain and extreme care is needed in its construction and design, because prac- The Modern Gasoline Automobile 227 tii-ally the entire duty of trans- mitting the power generated by tin- motor to the gearset de- M lives upon it. Crank shafts are usually made of high tensile strength steel of special composi- tion. They may be made in four wavs, the most common being from a drop or machine forg- ing which is formed approxi- mately to the shape of the fin- ished shaft and in rare instances they may be steel castings. Sometimes they are made from machine forgings, where con- siderably more machine work is necessary than would be the case where the shaft is formed between dies. Some engineers favor blocking the shaft out of a solid slab of metal and then machining this rough blank to form. In some single-cylinder motors of the enclosed fly-wheel i.v I M- the crank shaft and fly wheel are built up as a unit. The form of the shaft de- l"-nds on the number of cylin- ders and the form has material influence on the method of con- struction. For instance, a one-, two- or four-cylinder crank shaft could be made by either of the methods outlined. On the other hand, a three- or six-cylinder shaft is best made by the ma- chine forging process, because Fig. 104. Auxiliary Shaft Used in Con- nection with Cam Shaft Driven from a Spiral Gear Turns Timer and Oil Pump. 228 The Modern Gasoline Automobile if drop forged or cut from the blank it will have to be heated and the crank throws bent around so that the pins will lie in three planes one hundred and twenty degrees apart, while the other types described need no further attention, as the crank pins lie in planes one hundred OLTZD Dr-tnQ Fig. 105. Showing Method of Making Crank Shaft. A The Rough Steel Forging Before Machining. B The Finished Six-Throw, Seven-Bearing Crank Shaft. and eighty degrees apart. This can be better understood by referring to Fig. 105, which shows a six-cylinder shaft in the rough and finished stages. At A the appearance of the machine forging before any of the material is removed is shown, while at B the appearance of the finished crank shaft is clearly depicted. The built-up crank shaft is seldom used on multiple-cylinder motors, except in some cases where the crank shafts revolve on ball bearings and the connecting rods are provided with this form as well. A typical single-cylinder high-speed motor is shown at Fig. 106, this being the De Dion-Bouton, a power plant which has been quite popular in France in the past for " voiturette " or small car use. In this design the fly wheels are enclosed in the crank case and the crank shaft is a built-up construction formed of five pieces. The two halves of the crank shaft fit into taper holes in the fly wheels and are held securely in place by means of keys and clamping nuts. The crank pin is similarly retained. Brief study of the illustration will show this method of construction very clearly. It should be stated that this is seldom used on automobile motors but. that it is very common con- struction in motorcycle power plants. The Modern Gasoline Automobile 229 Flywheel Fig. 106. Defining Built-up Crank-shaft Construction Sometimes Used in Small Motors. 230 The Modern Gasoline Automobile Crank-shaft form will vary with a number of cylinders and it is possible to use a number of different arrangements of crank pins and bearings for the same number of cylinders. The simplest form of Fig. 107. Showing Form of Crank Shaft for Twin-Cylinder Opposed Power Plant. crank shaft is that used on a one-cylinder motor, as it would consist of but one crank pin, two webs, and the crank shaft. As the numbor Fig. 108. Two Forms of Four-Cylinder Crank Shaft. A Five-Bearing Type with Fly-wheel Fastening Key at Front End. B Three-Bearing Type with Flange for Securing Fly-wheel Formed Integral. of cylinders increase, as a general rule more crank pins are used. The crank shaft that would be used on a two-cylinder opposed motor is shown at Fig. 107. This has two throws and the crank pins are The Modern Gasoline Automobile 231 spaced 180 degrees apart. The bearings are exceptionally long and a flange is forged integral at the rear end for fly-wheel retention. Four- cylinder crank shafts may have two, three or five main bearings and three or four crank pins. In some forms of two-bearing crank shafts, such as used when four cylinders are cast in a block, or unit casting, two of the pistons are attached to one common crank pin, so that in reality the crank shaft has but three crank pins. Such a form is shown at Fig. 112, which depicts a four-cylinder two-bearing crank shaft used on Chalmers' motors. When the cylinders are cast individually five-bearing crank shafts are the rule. One of these, which is used on Maxwell engines, is shown Fig. 109. Representative Three-Bearing Crank Shafts. A For Use with Cylinders Cast in Pairs. B Used with Individually Cast Cylinders. Note Round Section Portions Connecting Ends to Center Crank Throws. at Fig. 108, A. The three-bearing type shown at Fig. 108, B, is used when the cylinders are cast in pairs. Two other three-bearing shafts used in four-cylinder motors are shown at Fig. 109. That at A forms part of the E. M. F. engine, whicli has the cylinders cast in pairs, while the three-bearing four- throw type, shown at B, is used in the Rambler four-cylinder engine, which has individually cast cylinders. Six-cylinder crank shafts usually have four or seven main bearings depending upon the disposition of the crank pins and arrangement of cylinders. At Fig. 110 the bottom view of a Premier six-cylinder engine with bottom half of crank case removed is given. This illus- trates clearly the arrangement of crank pins and main bearings when 232 The Modern Gasoline Automobile the crank shaft is supported on four journals. The crank shaft shown at Fig. 105, B, is a six-cylinder seven-bearing type. L Fig. 110. Bottom View of Premier Engine Showing Four-Bearing, Six-Cylinder Crank Shaft with Connecting Rods in Place. Ball-Bearing Crank Shafts. While crank shafts are usually sup- ported in plain journals there seems to be a growing tendency of late to use anti-friction bearings of the ball type for their support. This is Fig. 111. Design of Four-Cylinder Crank Shaft Mounted on Two Annular Ball Bearings. Note Method of Fly-wheel Retention by Key and Taper and Bearing Housing. The Modern Gasoline Automobile 233 especially noticeable on block motors where but two main bearings are utilized. When ball bearings are selected with proper relation to the load which obtains they will give very satisfactory service. They permit the crank shaft to turn with minimum friction, and if properly i selected will never need adjustment. The drawing at Fig. Ill shows the usual method of mounting a four-cylinder crank shaft on two annular ball bearings. The front end is supported by a bearing which is clamped in such a manner that it will take a certain amount of load in a direction parallel to the axis of the shaft, while the rear end is > suppnrU'd that the outer race of the bearing has a certain amount Fig. 112. Four-Throw, Two-Bearing Chalmers Crank Shaft Mounted on Anti- Friction Journals of the Bali-Bearing Type. of axial freedom or " float." The inner race or cone of each bearing is firmly clamped against shoulders on the crank shaft. At the front end of the crank-shaft timing gear and a suitable check nut are used, while at the back end the bearing is clamped by a threaded retention member between the fly wheel and a shoulder on the crank shaft. The fly wheel is held in place by a taper and key retention. The ball bear- ings are carried in a housing of bronze or malleable iron, which in turn are held in the crank case by bolts. The two-bearing crank shaft shown at Fig. 112 is that used in Chalmers' motors, while a three- bearing crank shaft supported on anti-friction members of the ball typr which has been used successfully on Lozier cars is shown at Fig. 234 The Modern Gasoline Automobile 113. Figs. Ill and 112 show designs of two-bearing, four-cylinder crank shafts, such as used in block motors very clearly, while the form depicted at Fig. 113 forms part of a motor having the cylinders cast in pairs. Fig. 113. Four-Throw, Three-Bearing Lozier Crank Shaft and Connecting Rod Assembly Mounted on Three Large Annular Ball Bearings. Note Con- necting Rod Design and the Use of Plain Bearings at Both Wrist-pin and Crank-pin Ends. Fly-wheel Construction and Retention. In explaining the princi- ple of operation of the internal combustion engine it was made clear that there were four strokes of the piston necessary to complete the cycle of operation in any one cylinder, and of these but one was a useful or power stroke. The gasoline engine would not be a practical The Modern Gasoline Automobile 235 p<>\ver producer, especially if made in one- and two-cylinder patterns, without some means of equalizing the uneven power generation. Con- sidering first the single-cylinder motor, we find that we have but one explosion every four strokes, and as this represents two revolutions of the crank shaft it will be evident that it is necessary to store up energy 1\ some means in order to carry the crank shaft through the idle strokes. This is accomplished by supplying a heavy- wheel which is Mvured in a positive manner to the crank shaft and which turns with it. When the explosion drives the piston down considerable energy i- -tred in the fly-wheel rim and it will continue to revolve after the impulse given it has diminished in value to a considerable extent. In t'ai-t there is enough energy stored in the fly wheel of proper weight to carry the piston through all the idle strokes and to equalize the i or- 1 ue produced. This insures an even turning moment and makes for uniform application of power to the mechanism. The fly-wheel weight is dictated largely by the number of cylin- ders employed, it being a general rule that the motors having the least number of cylinders require the heaviest fly wheels. This means that a single-cylinder motor will need a heavier equalizing member than one having a greater number of cylinders and a more even turning n 101 1 ient at the crank shaft. As an example of how the number of cylinders directly affects fly-wheel weight, one may say that if a single- cylinder engine of given power required a fly wheel of two hundred pounds weight to equalize the power effect, a double-cylinder engine would need one of about one hundred and sixty pounds, a four-cylin- der engine would use one weighing but one hundred pounds, while a .-i \-cylinder motor would furnish a uniform torque with a fly-wheel member weighing no more than sixty pounds. Fly-wheel weight is determined by many conditions, some of the important ones being bore of the cylinder, speed of crank-shaft rotation, degree of compression, and mode of transmission. It is common practice to provide a fly wheel somewhat heavier than the actual requirements on multi-cylin- der motors of large bore so that these may be more easily started by a person of average strength. Fly-wheel types vary from simple spoked members resembling a belt pulley with a heavy rim to others having fan-shaped spokes and liu r ht rims. Where a sliding gear transmission is used it is customary 236 The Modern Gasoline Automobile to make one of the clutch members integral with the fly wheel. For instance, at Fig. 114 a typical fan-blade fly wheel adapted for use with a cone clutch is shown. This has a central web member which forms Fig. 114. Typical Fly Wheel Showing Female Member of Cone Clutch and Fan- Blade Spokes. Rim is Light Because of Large Diameter. the back of a saucer-shaped casting which serves as a female member of the cone clutch. From the periphery of this, the spokes radiate to the rim. As the fly wheel is of comparatively large diameter the rim is lighter than would be necessary if the weight were concentrated nearer the center of the crank shaft. At Fig. 115 the rear view of a power plant is given showing a simple type of fan-blade fly wheel, The Modern Gasoline Automobile 237 which is secured to the crank shaft by means of four bolts. As this member is designed for use with a type of gearset with the clutches Fig. 115. Rear View of Overland Power Plant Showing Fan-Blade Spoke Fly- wheel Construction. incorporated, it is not necessary to provide for part of the clutch in the fly-wluvl casting. The diameter of a fly wheel must be held to certain limits and this restricts the useful weight one can put at the rim. If the fly 238 The Modern Gasoline Automobile wheel is placed low in the car it cannot be of large diameter, becfmse one must have at least twelve or fourteen inches clearance between the bottom of the fly wheel and the roadway. Then again, the factor of centrifugal force must be taken into account, as when a fly wheel re volves there is a tendency for the particles of which it is composed to fly out in a direction tangential to the circle of rotation, and this force tends to rupture the rim. If steel is used instead of cast iron, the fly wheel may be of larger diameter, because the stronger material has greater resistance to this rupturing stress, but these wheels are not easy to make because in ordinary motor car sizes they must be steel castings and are thus quite costly. For a cast-iron fly wheel a safe value for speed of rotation of a point on the rim is about a mile a minute. It will be seen that the diameter must be such that the fly wheel may be run at maximum speeds without danger of bursting. A fly wheel having a solid web joining the hub and rim is consid- erably stronger than one of the spoke type. The object of providing spokes shaped like fan blades is to take advantage of a suction effect produced to draw air from the motor compartment and exhaust it under the car. In some cars the draft created by the fly wheel is de- pended upon to supply the air needed for cooling the engine, either by applying it directly to the cylinders or by pulling it through the interstices of a water-cooling radiator. It is considered desirable to concentrate as much of the weight of the fly wheel at the rim as pos- sible, because the further away from center the weight is carried the more effective the fly wheel is as a reservoir of energy and equali/cr of torque. Positive Fly-wheel Retention Important. Methods of fly-wheel re- tention vary to some extent, and the main point observed by most designers is to use as secure a method of attaching it to the crank shaft as possible. The common systems of retention employed are shown at Fig. 116. The simplest of these is depicted at A. This consists merely of forcing the shaft into the fly-wheel hub and keeping the fly wheel from turning on the shaft by a substantial key which fits keyways machined in both shaft and fly-wheel hub. This method was for- merly used to a greater extent than it is at present, but its use has been practically abandoned, except on marine engines, because the means of fastening was not reliable. The intermittent application of The Modern Gasoline Automobile 239 power to the fly wheel meant that its speed of rotation was accelerated at a certain point of the crank-shaft travel corresponding to the power stroke and checked at the other, or idle strokes. This produced stresses which tended to loosen the fly wheel on the key, and as soon as the retaining member was slightly loose a very disagreeable knocking Fig. 116. Outlining Methods of Fly-wheel Retention Commonly Used. A By Gib Key. B By Woodruff Key, Taper and Clamp Nut. C By Bolting to Flange Forged Integrally with Crank Shaft. sound was produced by the hammering action of the loose fly wheel on its retaining key. At B a system often employed on types of crank shafts where it i- n>t practical to use the preferred method shown at C is outlined. For instance, when ball bearings are applied it is necessary that they be put on the shaft from each end and if a flange was formed integral it would not be possible to use ball bearings except of very large bore. 240 The Modern Gasoline Automobile Then again, some engineers using alloy steel for crank-shaft construc- tion machine it from a slab of that material, and in order to reduce cost of manufacture no attempt is made to form the flange integral with the shaft. In this the end of the shaft designed to support the Fig. 117. Showing Method of Marking Rim of Six-Cylinder Fly Wheel for Guiding Repairman or Motorist to Retain Correct Valve Timing. fly wheel is tapered, as is also the fly-wheel hub. In addition to the taper a Woodruff key is usually let into the shaft and keyway cut into the fly-wheel hub to receive it. When the fly wheel is forced on the taper by the clamping nut it is firmly retained by the key, and at the The Modern Gasoline Automobile 241 same time the wedging effect of the taper and the pressure of the damping nut prevents the fly wheel from loosening. The fly wheel at B has a portion of the rim machined on a taper, so it can receive the male member of a cone-type clutch. The fly wheel shown at C is held by the preferred method. In forging the crank shaft a flange is formed integral and the fly wheel is secured to this flange by means of suitable retaining screws or bolts. If these are properly fitted it is practically impossible for the fly wheel to loosen on the flange, and as the flange is a part of the shaft it is obviously impossible for it to become separated therefrom. The fly wheel shown at C is provided with a casing formed integral which is designed to receive a clutch of the multiple-disk pattern. The writer has previously explained the action of the valve mech- anism and diagrams have been presented to show the sequence of the strokes. Most manufacturers mark the fly wheel with the various points at which valves should open or close. This not only facili- tates work at the plant of the producer, but it insures that the timing will be restored to the proper point in event of taking the engine down for repair at some garage or machine shop. The various points are laid out on the fly-wheel periphery by means of steel stamps or letters, which may be easily interpreted. The position of these lines is deter- mined by the peculiarities of that specific engine, and will vary in the different designs. The layout is always made with reference to some fixed point on the motor bed, this usually being a small metal pointer attached to a center point and known as a " trammel." The various points at which valves should open and close for a typical six- cylinder engine are clearly shown laid out on the fly-wheel rim at Kg. 117. Engine-Base Construction. One of the important parts of the power plant is the substantial casing or bed member, which is em- ployed to support the cylinders and crank shaft and which is attached directly to the motor-car frame. This will vary widely in form, but as a general thing it is an approximately cylindrical member which may be divided either vertically or horizontally in two or more parts. Automobile crank cases are usually made of aluminum, a material which has about the same strength as cast iron, but which only weighs a third as much. In some cases cast iron is employed, but is not '242 The Modem Gasoline Automobile favored by most engineers because of its brittle nature and low re- sistance to tensile stresses. Where exceptional strength is needed al- loys of bronze are used, and in some cases where cars are produced in large quantities a portion of the crank case may be a sheet steel or aluminum stamping. Crank cases are always large enough to permit the crank shaft and parts attached to it to turn inside and obviously its length is deter- Tig. 118. Crank Case of Reo Four-Cylinder Motor, a Barrel Type with Ends Closed by Plates which Support Crank Shaft. mined by the number of cylinders and their disposition. The crank case of the single-cylinder or double-opposed cylinder engine would be substantially the same in length. That of a four-cylinder will vary in length with the method of casting the cylinder. When the four cylinders are cast in one unit and a two-bearing crank shaft is used, the crank case is a very compact and short member. When a three-bearing crank shaft is utilized and the cylinders are cast in pairs, the engine base is longer than it would be to support a block casting, but is The Modern Gasoline Automobile 243 shorter than one designed to sustain individual cylinder castings and a five-hearing crank shaft. A four-cylinder crank case of the harrel type is shown at Fig. 118. The construction calls for the use of end-bearing plates, which carry the front and rear main journals. In order to gain access to the in- terior, large openings are provided at the side of the case and closed l)\- plates when the assembly is completed. The cylinders are held in place by a series of stud bolts screwed into the top of the case, and a similar method of retention is utilized for the end plates. A projec- tion from the side serves to house the cam shaft, while the motor- Fig. 119. Crank Case of Corbin " 40 " Power Plant Made in Two Halves. Crank-Shaft Bearings and Caps Secured to Upper Half, which also Has Sup- porting Arms Cast Integral. Lower Portion of Crank Case Simply Acts as Oil Container. This is the Common Construction. timing gears are protected by a separate casting member, which is part of the front bearing plate. It is now common construction to asl an oil container integral with the bottom of the engine base and to draw the lubricating oil from it by means of a pump. The arms 244 The Modern Gasoline Automobile by which the motor is supported in the frame are substantial-ribbed members cast integrally. The approved method of crank-case construction favored by the majority of engineers is shown at Fig. 119, bottom side up. The upper half not only forms a bed for the cylinder but is used to hold the crank shaft as well. In the illustration the three-bearing crank shaft is shown resting in the upper main bearing boxes which form part of the case, while the lower brasses are in the form of separately cast caps retained by suitable bolts. In the construction outlined the bottom part of the case serves merely as an oil container and a pro- tection for the interior mechanism of the motor. Fig. 120. Bottom View of Inter-State Power Plant. Crank Case a Barrel Form with Removable Bottom Plate to Permit Access to Engine Interior. Im- portant Power Plant Parts Clearly Shown. In some instances where barrel-type crank cases are employed, in- stead of using hand holes for adjustment in the side, the design is as shown at Fig. 120. The bottom of the crank case is left open in cast- ing and is closed by a large plate. The interior parts of the engine 245 246 The Modern Gasoline Automobile are clearly depicted, as they appear viewed from the bottom, and the accessibility afforded by this design should be readily perceived. En- gineers who favor unit power plants often include a portion of the crank case with the housing for the clutch and gearset. Such a construction is clearly shown at Fig. 121. It will be seen that a sub- stantial yoke member which encircles the fly wheel is used to join the gear case to the engine base. In this view the method of retaining the five-bearing crank shaft to the upper half of the case is also shown. In designing crank cases the main thing to be considered is to have it of ample strength and to arrange the various parts so that the interior mechanism may be reached without dismantling the entire engine when adjustments are necessary. Typical Two-Cycle Motors. As a general rule the two-stroke cycle engines that have been adapted for automobile propulsion differ ma- terially from the simple forms previously described. Some makers, who use the simple form, have been able to secure very satisfactory results in practice by careful attention to port design. When a two- cycle motor is to be used for motor-boat propulsion, it is a moderate speed proposition and great flexibility or efficiency are not sought. In the automobile, however, the conditions that obtain make it necessary to design the power plant in such a way that it would have a wide range of speed and so that it can be easily accelerated from its lowest to its highest speed without missing explosions 01 running irregularly. A sectional view through the cylinder of the Amplex two-cycle motor is shown at Fig. 122, A. This motor is a simple construction which resembles the marine type in general design, though great care has been taken in proportioning the ports and gas passages to obtain the flexibility which is so essential to the motor-car power plant. This motor is a three-port type and the gas is taken into the engine base through ports which are uncovered by the piston when it reaches the end of its compression stroke. When the parts are in the position shown at A, the piston has reached the top of its stroke and the com- pressed gas in the cylinder is ready for ignition. At the same time the inlet ports just at the bottom of the piston have been uncovered and the gas flows through the intake manifold from the carburetor. In the other view shown at B, the position of the parts when the pis- ton has completed its power stroke is depicted. The exhaust port is l"j< 247 248 . The Modern Gasoline Automobile fully opened and the burned gases are discharged through it. Com- munication is also made between the engine base where the charge has received preliminary compression necessary to insure its transfer through the safety screen and the open ports in the cylinder wall. The entering fresh gas is deflected to the top of the cylinder by the deflector plate provided on the top of the piston, as is usual practice. The Amplex motor is a four-cylinder type and gives very satisfactory results in practice. The Legros two-cycle motor, which is of French derivation, em- bodies a distributor valve and a peculiar arrangement of pistons. In this construction a stationary member is placed inside of the regular working piston and it is the space between these members that is utilized to store the gas taken in, prior to transferring it from the pump portion of the engine to the combustion chamber. The action is very similar to that of the usual form of differential piston motor. When the piston goes up on the compression stroke it draws in a charge of gas from the carburetor through the rotary distributor valve and up through the passage which joins the valve chambers to the space between the stationary and movable pistons. When the piston reaches the top of its stroke the rotary valve turns to such a position that it cuts off the carburetor from the pumping chamber and provides communication between the pumping chamber and the cylin- der by means of the usual transfer passage and inlet ports cored into the cylinder wall. Otherwise the action is just the same as that of the more simple forms of engines. The construction of this motor is clearly shown at Fig. 123, and as all parts are clearly indicated the principle of operation should be easily grasped. Another differential piston motor designed by a French engineer, Monsieur Cote, is shown at Fig. 124. In this a double-diameter piston is used and the cylinder is formed so that the smaller of these members fits the upper portion while the large end of the piston fits the correspondingly enlarged lower portion. The functions of com- pression and explosion of the charge take place in the smaller cylinder, while the lower member acts as a pump. On every downstroke of the piston a charge of gas is drawn into the annular space between the piston and cylinder wall, and on every upward stroke it is compressed and forced into the working cylinder adjacent. The construction out- Fig. 123. Sectional View Showing Construction of Legros (French) Motor Defining Peculiar Cylinder Construction. 249 250 The Modern Gasoline Automobile lined is applicable only to motors having an even number of cylinders. and the arrangement must be such that they will work in pairs and that the piston in one cylinder will be at one end of its stroke while Con pr Spark Plug ession Relie f Cock Cctnbustion Chamber Cylinder Water Space Cranhcase -" Flywheel Fig. 124. The Cote (French) Two-Cycle Motor is a Good Example of the Type Employing a Two-Diameter Piston and Distributor Valve. that of its mate is in the other extreme position. The peculiar type of transfer passage depicted is necessary because the pumping por- The Modern Gasoline Automobile 251 tion of one cylinder must be joined to the working portion of the other member. Outside of peculiarities of construction, the operating cycle is just the same as other two-stroke engines, and an explosion is ob- tained in each cylinder every two strokes of the piston. Fig. 125. The Rayner (English) Two-Cycle Motor Employs Distinctive Double- Piston Arrangement. A Side View Showing Crank Shaft and Connecting Rods. B End Section Showing Relative Angularity of Connecting Rods. C Inner Piston Uncovers Inlet Ports; Outer Piston Covers Exhaust Pas- sages. An unconventional two-cycle engine of English design is shown at Fig. r'.x Two pistons are used, one working inside of the other; the outer member carries an annular flange which fits the enlarged bore of the cylinder and acts as a pump for taking in the gas and sub- 252 The Modern Gasoline Automobile jecting it to preliminary compression. The pump chamber is divided from the crank case by a flange, which also acts as a guiding member for the bottom of the large piston. At the end of the downstroke each piston uncovers a ring of ports, the outer member opening the exhaust while the inner piston controls the inlet openings. A pecu- liar form of crank shaft having two throws for each cylinder is used, and the crank to which the inner piston is attached has twice the amount of throw the crank connected to the larger member has. This means that both pistons work in the same direction, but that the inner member travels twice the distance the big piston does. The, crank which controls the movement of the outer piston is given a lead of about twenty degrees so that the exhaust ports are opened at the proper time in relation to the opening of the inlet passages. When the pistons travel on the upstroke, the inner one is com- pressing a charge previously supplied the working cylinder and simul- taneously fresh gas is being inspired into the pump chamber. When the pistons reach the top of the stroke the spark takes place and the resulting explosion drives the piston down and imparts power to the crank shaft in the usual manner. At the same time that the pis- tons are driven down by the explosion, the new charge which has been drawn in through the pump chamber is partially compressed. Near the end of the stroke the outer piston uncovers the exhaust ports, and the burned gases escape by virtue of their pressure. The inlet ports open and new gas enters the cylinder in the usual manner and is directed to the top of the cylinder by the peculiar formation of the outer piston, which acts as a chimney to direct the gases to the top of the combus- tion chamber. As the new charge enters at considerable speed the high velocity of the gas forces out the burned products and insures thorough scavenging. The view at A is a side section and depicts the arrangement of the pistons relative to each other and the peculiar arrangement of the crank shaft. At B an end section is presented, this to show the angularity of connecting rods, showing how the short throw crank is given a slight lead over that which works the inner piston. The inset at C is given to enable the reader to understand the principle involved in controlling the intake and exhaust ports. Typical Four-Cycle Power Plants. The writer has previously men- tioned the fact that most engineers favor the four-cycle form of power The Modern Gasoline Automobile 253 plant, and the majority of the descriptive matter presented in this chapter has dealt specifically with this form of engine. As a fitting conclusion a brief description of some representative American power plums will he given. At Fig. 126 the inlet" side of a four-cylinder water-cooled motor is illustrated, while the exhaust side of the same power plant is depicted at Fig. 127. It will be observed that the Fig. 126. Inlet Side of Typical Four-Cylinder Power Plant Showing Carburetor and Magneto Placing. carburetor and magneto are placed on the side of the motor with the inlet valves while the water pump is installed on the exhaust side. The front end of the power plant is supported by a steel member bolted to the upper part of the crank case, while the rear portion is fastened to the frame by means of arms cast integral Vith the upper half of the engine base. The cylinders are cast in pairs with water jackets integral, while the engine base is made in three pieces and is (.livided horizontally. Fig. 127. Exhaust Side of Four-Cylinder Power Plant Showing Water Punr Location. Fig. 128. Valve Side Regal Motor Showing Compactness of Design Possible with L Cylinder Construction. Note Manifold Placing and Magneto and Carburetor Location. 254 The Modern Gasoline Automobile 255 The valve side of a light four-cylinder power plant used on Regal motor cars is shown at Fig. 128. This demonstrates clearly the com- pact design possible with " L " head cylinders, which permits placing both inlet and exhaust valves on the same side of the motor. The placing of the magneto and the method of protecting the wires lead- ing from it to the spark plugs at the top of the cylinders, as well as ?ig. 129. Exhaust Side of Columbia " Mark 85 " Motor. Note Enclosed Valve Springs and Arrangement of Parts. the method of retaining the inlet and exhaust manifolds, are clearly outlined. Xo water pump is employed on this engine, the natural ar thermo-siphon system of water circulation being depended upon to adequately cool the cylinders. The exhaust side of the Columbia Mark 85 four-cylinder motor is illustrated at Fig. 129. In this the cylinders are of the "T" head typo and are cast in pairs. Attention is called to the method of en- 256 The Modern Gasoline Automobile closing the valve springs and operating plungers to keep them free of grit and to minimize noise incidental to the valve mechanism. The wter pump is driven by a shaft extending from the gear case at the front end of the motor while the oil-circulating pump is suspended at the rear of the crank case between the oil container and the fly wheel. While the greatest number of automobiles use four-cylinder power plants, there are a number of manufacturers who provide engines hav- Fig. 130. Inlet Side of Matheson " Silent Six Power Plant, an Overhead Valve Type. ing six cylinders. As a rule these do not differ materially from the four-cylinder forms, except for the addition of an extra pair of cylin- ders and the added length to the crank case that this makes necessary. The six-cylinder motor shown at Fig. 130 is a distinctive construction in which the cylinders are cast in pairs and have valves in the head. A very compact power plant is made possible by the peculiar form of the cylinder castings which have flat ends so that they can be placed very close together. It is seldom that more than six cylinders are used, but there have been automobiles made for racing purposes that had eight and even twelve cylinders. The Modern Gasoline Automobile -57 When an eight-cylinder motor is used it is usually of the " V " type, i. e., the cylinders are arranged in two sets of four, as shown at Fig. 131. This view represents a motor which has been designed for Fig. 131. View of Eight-Cylinder Hendee Motor, a Type Seldom Used on Motor Cars, but Popular for Aviation. Eight-Cylinder Motors Designed for Automobile Propulsion are Always of the V Type, which Permits Com- pactness and no Greater Overall than the Usual Four-Cylinder Power Unit. aeronautic service, but when eight-cylinder power plants are used for automobile propulsion they are built very much the same. The reason that the cylinders are arranged opposite each other and at an angle in- stead of being placed one after the other is that the " V " construe- 258 The Modern Gasoline Automobile tion makes it possible to use a crank case which is not much longer or heavier than would be needed for the conventional four-cylinder mo- tor. An eight-cylinder engine is rather complicated, and difficulties obtain in lubrication, cooling, and ignition, so that this type is not, apt to become very popular, even though it furnishes power very stead- ily when all cylinders are working. An eight-cylinder motor of the four-cycle type will give four explosions every revolution of the crank shaft or one impulse every quarter turn. A car equipped with such a motor would be much more flexible than with a lesser number of cylinders, but as the four- and six-cylinder forms give practically a uniform and regular turning movement of the crank shaft it is not considered advisable to use more than six cylinders in touring cars and four cvlinders in motor trucks. Fig. 131a. Part Sectional View of the De-Dion Eight-Cylinder " V " Type Auto- mobile Motor. The Modern Gasoline Automobile 259 The cross section of the De-Dion 8-cylinder V type automobile motor is outlined at Fig. 13 la. The c} r linders are water-cooled with in- tegral L head and water jackets, and have the valves placed side by side, so that all valves may be operated from a common camshaft. The cam- shaft is mounted directly above the crankshaft in the portion of the case between the two sets of cylinders. It is disposed in such a way that simple rocker levers or bell cranks which carry rolls at one end will ride on the cams and lift the valves by the conventional push-rods carried in guides at the top of the crank case. The valve action is ingenious and offers the important advantage of employing but one cam for two of the valves in opposite cylinders. This type of motor has received but limited application in automobiles. Cyclecar Power Plants. The type of power plant utilized in cycle- car propulsion depends entirely upon the nature of the vehicle. For instance, the simple type or true cyclecars use motors patterned after forms that have received general application in motor-cycle service, while the light cars or those which follow automobile practice more closely employ water-cooled motors, usually of the four-cylinder type. The engine shown at Fig. 1316 is a two-cylinder form that will develop about 12 H. P. at a maximum speed of 2,500 r. p. m., and follows motor bicycle practice very closely in that it employs two air-cooled cylinders, disposed one each side of the crank case centre line at an an- gle of about 22$ degrees with the crank case centre line, or one might say that the two cylinders had an included angle of 45 degrees. As is common with the light engines used in motor cycles, the inlet valves are mounted above the exhaust valves and are operated by tappet rods and rocker arms, whereas the exhaust valve stems are actuated directly by the usual form of push rods. In order to make for stead} r running, the motor is provided with an outside flywheel in addition to the bal- ancing members mounted inside of the enclosed crank case. To in- sure adequate cooling when the vehicle is standing still, a two-blade fan directs a current of air against the cylinders. Ignition is by high /tension magneto and the weight of the entire power plant, including magneto, carburetor, external flywheel, and cooling fan, is but one hun- dred pounds. This type of motor is efficient, fairly well balanced, and powerful enough for the simple form of cyclecar that does not weigh over five or six hundred pounds. It will propel such vehicles at speeds 260 The Modern Gasoline Automobile The Modern Gasoline Automobile 261 262 The Modern Gasoline Automobile The Modern Gasoline Automobile 263 up to 50 miles per hour without difficulty, and is very economical of fuel, inasmuch as one gallon of gasoline will serve for 50 miles if the carburetor is properly adjusted. Another form of motor which has been adapted to cyclecar service in England is shown at Fig. 131c. This is a two-cylinder water- cooled type having the cylinders cast in a pair with a common water- jacket. The cylinders are of the T-head type and follow conventional practice in regard to the location and operation of the valves. It will be noted that the crank pins are spaced 180 degrees apart, which means that while the engine has a fair mechanical balance, it will not have a good explosion balance, because the power impulses are not separated by equal intervals, one occurring immediately after the other and then a lapse of one turn of the flywheel takes place before another power impulse is obtained. This form of motor is used to eome extent, but is not as popular as the V type, when only two cyl- inders are used. The two-cylinder vertical form has received much wider application in Europe than in America. In this country the two- cylinder V type or horizontal opposed motors are preferred. Many four-cylinder motors employed on light cars follow the gen- eral lines of design depicted at Fig. I31d. This motor, which is utilized on the Maxwell " 25 " automobile, is of.the same general pat- tern employed in the Ford, Metz and other light cars. The cylinders and upper half of the crank case are cast together, while the cylinder head, which* also includes the valve chamber, is a separate casting secured to the cylinder block by bolts. A gas-tight joint is obtained between the two members by a copper asbestos gasket, which is tightly compressed to form a very satisfactory packing when the retention bolts are properly tightened. CHAPTER V Defining the Liquid Fuels Commonly Used and Methods of Vaporizing to Obtain Explosive Gas Methods of Carrying Fuel in Automobiles De- velopment of Modern Carburetor from Early Vaporizer Forms Elements of Carburetor Design Outlined Typical Gasoline Vaporizers Described in Detail How Kerosene May be Utilized Discussing Fuel Supply by Direct Injection Inlet and Exhaust Manifold Design Muffler Forms in Common Use. THERE is no appliance that has more material value upon the effi- ciency of the internal combustion motor than the carburetor or vapor- izer which supplies the explosive gas to the cylinders. It is only in recent years that engineers have realized the importance of using car- buretors that are efficient and that are so strongly made that there will be little liability of derangement. As the power obtained from the gas engine depends upon the combustion of fuel in the cylinders, it is evident that if the gas supplied does not have the proper propor- tions of elements to insure rapid combustion the efficiency of the engine will be low. When a gas engine is used as a stationary instal- lation it is possible to use ordinary illuminating or natural gas for fuel, but when this prime mover is applied to automobile or marine service it is evident that considerable difficulty would be experienced in carrying enough compressed coal gas to supply the engine for even a very short trip. Fortunately, the development of the internal com- bustion motor was not delayed by the lack of suitable fuel. Engineers were familiar with the properties of certain liquids which gave off vapors that could be mixed with air to form an explo- sive gas which burned very well in the engine cylinders. A very small quantity of such liquids would suffice for a very satisfactory period of operation. The problem to be solved before these liquids could be applied in a practical manner was to evolve suitable apparatus for vaporizing them without waste. Among the liquids that can be com- bined with air and burned, gasoline is the most common and is the 264 The Modern Gasoline Automobile 265 fuel utilized by the majority of internal combustion engines employed in self-propelled conveyances. The widely increasing scope of usefulness of the internal combus- tion motor has made it imperative that other fuels be applied in some instances because the supply of gasoline may in time become inade- quate to supply the demand. In fact, abroad this fuel sells for fifty to two hundred per cent more than it does in America because most of the gasoline used must be imported from this country or Kussia. Because of this foreign engineers have experimented widely with other substances, such as alcohol, benzol, and kerosene. The proper- ties of these fuels, their derivation and use should be considered fully before describing the types of apparatus utilized for vaporizing them. Distillates of Crude Petroleum. Crude petroleum is found in small quantities in almost all parts of the world, but a large portion of that produced commercially is derived from American wells. The petro- leum obtained in this country yields more of the volatile products than those of foreign production, and for that reason the demand for it is greater. The oil fields of this country are found in Pennsylvania, Indiana, and Ohio, and the crude petroleum is usually in association with natural gas. This mineral oil is an agent from which many compounds and products are derived, and the products will vary from heavy sludges, such as asphalt, to the lighter and more volatile com- ponents, some of which will evaporate very easily at ordinary tem- peratures. The compounds derived from crude petroleum are composed prin- cipally of hydrogen and carbon and are termed " Hydro-Carbons." In the crude product one finds many impurities, such as free carbon, sulphur, and various earthy elements. Before the oil can be utilized it must be subjected to a process of purifying which is known as re- fining, and it is during this process, which is one of destructive dis- tillation, that the various liquids are separated. The oil is broken up into three main groups of products as follows : Highly volatile, naph- tha, benzine, gasoline, eight to ten per cent. Light oils, such as kero- sene and light lubricating oils, seventy to eighty per cent. Heavy oils or residuum, five to nine per cent. From the foregoing it will be seen that the available supply of gasoline is determined largely by the de- 266 The Modern Gasoline Automobile mand existing for the light oils forming the larger part of the prod- ucts derived from crude petroleum. As a very small portion of the distillates can be used with ordinary vaporizing devices any improvements to make possible the use of less liquid or utilize the cheaper fuels, such as kerosene, will be of great value in increasing the usefulness of internal combustion motors. Considerable attention is being given to mixing devices which will permit the use of kerosene, and many authorities have agreed that this material or alcohol will be the fuel of the future. To show the enor- mous consumption of gasoline in this country, it has been said that if all of the engines in use which depended on this fuel were to be oper- ated continuously together for a ten-hour day that over five million gallons of liquid would be consumed. When one considers that the number of explosive engines is constantly augmenting it will not be difficult to perceive the reason why the development of devices to use fuels other than gasoline should be encouraged. Benzol and Its Properties. In England, where gasoline sells for fifty cents a gallon or one hundred and fifty per cent more than the average price in this country, engineers have sought to use benzol, which is said to be adaptable to the present types of motors without change, and in cases where it has been used as much power is obtained as with gasoline. This material is a by-product incidental to the manufacture of illuminating gas and coke, and while it was formerly distilled from coal-tar and obtained only in small quantities, improved methods make it possible to produce about three gallons from every ton of coal changed into coke or gas. The former material was at one time produced by a process which permitted the gas to escape, but at the present time this is retained and condensed to form benzol. The crude product is a foul-smelling liquid which has about the same con- sistency and color as heavy ale. When subjected to a refining process the dirty liquid is converted to one that is about the same color as water. Benzol is not so volatile as gasoline, but it is claimed that a motor may be started without difficulty with this fuel supplied to a carbu- retor of ordinary construction. Owing to the greater number of heat units it contains, it is said it will develop more power than gasoline, and as it will not evaporate so readily it does not become stale or The Modern Gasoline Automobile 267 heavy by the vaporization of the lighter constituents. A disadvantage incidental to its use has been that owing to it being richer in carbon than gasoline it would deposit more of this substance on the piston head and interior of the combustion chamber. While this may be true of a poorly refined benzol and when mixture proportions are not cor- rect, it applies equally well when low grades of gasoline are used and when the mixture of gasoline vapor and air supplied the cylinders is too rich. Special Vaporizers Needed for Kerosene. As kerosene forms one of the larger portions of the distillates of crude oil it is apparent that if this material could be used as fuel for internal combustion engines it might replace gasoline to a certain extent. If considered from a point of view of heat units contained or heating value kerosene would be a better fuel than gasoline, though considering it with its other disadvantages in mind it is not so suitable for use in existing types of motors. The chief difficulty which retards its use is that it will not vaporize readily at ordinary temperatures, and before it will evap- orate sufficiently to form a gas with air it must be heated. This calls for specially constructed vaporizing devices and jacketed manifolds, which will be described in proper sequence. Owing to the low rate of evaporation it is contended that it cannot be used successfully on high- speed motors where flexibility of control is desired and where the engine must be accelerated from its minimum to the highest speed in a short time. On slow and moderate speed motors, such as used for stationary and marine service, kerosene has been employed with some degree of success. It contains more carbon in its composition, and as the combustion of kerosene vapor is not so apt to be as complete as gasoline gas, more carbon will be deposited in the interior of the com- bustion chamber than when gasoline is burned. Advantages of Alcohol. Considerable experimenting with alcohol has been done by French and German engineers, and there are many points to be considered in its favor when discussing its value as a fuel. Alcohol, instead of being derived from natural mineral deposits, which become more and more depleted as the demands increase, is derived from various plants and vegetables and is the one fuel that can be produced in quantities that could be augmented as the demand for it increased. The vegetable substances which are distilled to make alco- 268 The Modern Gasoline Automobile hoi are reproduced each cycle of seasons, and in tropical countries there is no cessation to the growth of the vegetation. The raw mate- rials from which alcohol may be manufactured are found in all parts of the earth. It is derived from any substance which contains either starch or sugar, and it can profitably be produced from fruits, grains, and vegetables. It may be made from beets, sugar-cane, rice, barley, rye, corn, wheat, or potatoes, and decaying fruit or other refuse, which could not be utilized otherwise, may be subjected to a process of distillation and alcohol derived therefrom. Alcohol differs materially from gasoline, and as it is less volatile it requires more heat to vaporize it. Alcohol vapor can be compressed to a greater degree than the vapors of gasoline, and as the heat units liberated from a fuel vary with the degree of compression even though alcohol gives out less heat when burned under the same conditions, higher efficiency may be obtained by compressing the alcohol vapor to a higher degree. While this substance has been used for a decade or more abroad, in engines designed especially for its use, it has not been applied with any degree of economy in motors designed for use with gasoline. A motor constructed for use with alcohol must use a higher degree of compression than a gasoline motor, and a form of carburetor which will heat the mixture before it is taken into the cylinder should be used. An engine designed for gasoline will use twice as much alcohol as it does gasoline to develop the same amount of energy, though in a special motor the same amount of power will be obtained as when equal quantities of gasoline are burned in the conventional engine. One of the disadvantages of alcohol that is shared in common with kerosene is that it is difficult to start an engine when cold, as alcohol is not very volatile unless heated. The amount of air necessary for complete combustion is roughly estimated at one third that needed with gasoline. Twice the amount of compression before ignition can be used with alcohol vapor. The range of explosive mixture proportions of alcohol and air is much greater than that possible with gasoline and air. Various authorities have stated that a compression of one hundred and fifty pounds per square inch is possible with alcohol, but it is doubtful if automobile engines will ever be built using such high degrees of compression. The Modern Gasoline Automobile 269 A new process has been recently developed with a view of permit- ting one to use alcohol in engines of present design with no change except a special form of vaporizer. In this the alcohol vapor is passed through calcium carbide before it enters the cylinder. The water which is present in commercial alcohol and which lowers its efficiency as a fuel is absorbed by the carbide and the resulting chemical action liberates acetylene gas. This is very inflammable and increases the ex- plosive value of the alcohol vapor. When the alcohol-acetylene combi- nation is used, to obtain the same thermal efficiency as with gasoline gas, it is necessary to add water to the alcohol until a solution con- taining seventeen per cent water and eighty-three per cent alcohol is obtained. This is no great disadvantage, as water costs nothing to speak of, and the increase in the bulk of the fuel nearly pays for the carbide. It is estimated that one pound of carbide is used per gallon of liquid. As the market price of carbide in lots of one hundred pounds or more is but four to five cents per pound, the only objection that can be ad- vanced to the process is the increased complication of the vaporizing appliance. The combination of alcohol and acetylene has proved effi- cient on motors employing compressions as low as sixty pounds to the square inch and running as high as two thousand revolutions per min- ute, but when used alone the slow burning qualities of alcohol vapor has made it most efficient on slow-speed high-compression motors. Alcohol used for fuel purposes must be rendered unfit for drinking by mixing substances with it which are not palatable, but which do not interfere with its use as a fuel. When so treated the substance is called denatured alcohol. Among the substances which may be mixed with the ethyl alcohol are wood alcohol, benzine, and benzol, and various distillates of crude petroleum. Chemists contend that it is better to use a hydrocarbon, such as benzol, than the wood alcohol, as a denaturizing substance, because wood alcohol tends to produce acetone and other compounds which are of corrosive nature and which might corrode the metal parts of the cylinder which were exposed to the effects of a by-product resulting from incomplete combustion of such a vapor. Alcohol has the advantage in that the fire risk is less than with gasoline. The latter is a more volatile liquid than alcohol, and is 270 The Modern Gasoline Automobile more dangerous because it evaporates more readily. The flame of burning gasoline is one which radiates heat rapidly, whereas the alco- hol flame does not radiate heat to such an extent. A mass of burning gasoline will generate sufficient heat to set objects at a considerable distance from it on fire. The heat from burning alcohol goes upward and exists mostly in the hot gases evolved by the flame. A gasoline fire is spread by water, whereas burning alcohol may be extinguished by it. Gasoline is much lighter than water and floats on its surface, but alcohol is so nearly the same density that it will mix with the water. If one compares the chemical composition of alcohol and gasoline it will be found that it requires less air to burn a pint of alcohol than the same amount of gasoline. The oxygen contained in the alcohol tends to make combustion better, and there is practically no residue left in an engine burning alcohol gas. The exhaust from any of the petroleum distillates will smell strong and be smoky if an excess of fuel in proportion to air is in the mixture. The burned products of an alcohol mixture are not objectionable even if there is an excess of alcohol. These exhaust gases besides being more agreeable to the senses are cooler and cleaner, and as they contain a smaller propor- tion of free carbon less of this is deposited in the combustion chamber and muffler. Among the conditions which are unfavorable to the use of alcohol and which militate against its use at the present time can be cited the present types of engines and carburetors, and the high price of denatured alcohol. While alcohol has not been extensively experi- mented with in this country, because the supply of gasoline at the present time seems adequate, it is expected that, should there be a shortage of this valuable commodity, forms of vaporizers will be devised which will permit the use of alcohol in connection with pres- ent-day forms of motors. Some authorities contend that alcohol will be the fuel of the future, while others believe that kerosene is more adaptable for use in the hydrocarbon motor. Solid Gasoline as a Fuel. Experiments are being conducted in Europe with gasoline in the solid form, which is said to have some advantages over the liquid fuels. Solid gasoline is a transparent product which is in the form of a jelly, having sufficient consistency The Modern Gasoline Automobile 271 so that it can be handled like any other solid body. It can be cut into pieces just as gelatine can, and may be conveyed in wooden or cardboard boxes. If examined under the microscope its structure is similar to that of a very fine sponge and the theory is that liquid gaso- line is present in the pores. Its properties in general are the same as liquid fuels as it evaporates very easily, and has the same heat value. When solid gasoline is heated it does not melt under ordinary condi- tions but evaporates. If it is lighted it does not melt, but burns like wood, and the flame may be easily extinguished by covering with a piece of cloth. Solidified gasoline has about eighty per cent the bulk of ordinary liquid gasoline; whereas a gallon of liquid will occupy a space of 231 cubic inches, the same amount solidified will occupy but about 185 cubic inches. The mixture may be easily obtained, as solid gasoline dissolves in air at ordinary temperatures and yields a combustible gas which may be used in explosion motors. Solid gasoline can be used without first converting it into a liquid and a mixture of gasoline vapor and air is formed by causing a slightly heated current of air to pass over the surface of the solid fuel. It is claimed that a very good mixture is obtained. Appliances designed for carbureting solid gasoline utilize the exhaust gases of the motor as a source of heat for securing more ready evaporation. In the experiments made abroad a special form of carburetor was constructed to use with solid fuel. This was composed of a box with a series of pipes in its lower portion through which the exhaust gases from the engine were passed. A plate which formed the bottom of the fuel compartment which was 28 inches by 17 inches wide by 17 inches high was placed on these pipes. The solid gasoline was not placed directly on the bottom of the box but on a wire mesh screen which formed a false bottom, raised about two inches from the true bottom of the fuel compartment. Four cakes of solid fuel, each seven inches square by three and one half inches thick, were placed on the wire screen. An air inlet was provided at one end of the box, the air being drawn through the space between the bottom of the fuel box and the false bottom of wire mesh on which the fuel rested. As it passed it brushed by the gasoline which had been forced through the mesh in a form very much the same as icicles and which offered a very 272 The Modern Gasoline Automobile large surface for contact. The carbureted air was passed into a mix ing box fitted with extra air openings and from thence to the inlet pipe of the motor. Four gauze screens were interposed between the mixing and fuel chambers in order to prevent ignition of the gas in the fuel compartment should the motor back fire. When the apparatus was cold the motor did not run very well, but after it had been running for several minutes and the heating pipes raised in temperature the engine worked very well. This crude ex- periment showed that the ratio of weight of solid gasoline to the liquid fuel for equal work done was eighty-three and five tenths per cent, which meant that considered on a basis of weight that twenty-three per cent less solid fuel was needed to obtain the same power, and that eighty-three and five tenths per cent of solid gasoline would do as much work as one hundred per cent of liquid fuel. It is not likely that gasoline in this form will ever be used to any extent because the carburetor used will have to be very bulky and very much different in construction from that used for the liquid. The argument that solid gasoline is safer than liquid gasoline is not borne out by facts because it will evaporate quite readily and give off vapors at ordinary temperatures. It is open to question whether a fuel can be handled easier in solid or liquid forms. It would seem to the writer that it would be as easy to pour fuel out of a can directly into a suitable container as it would be to handle it in the form of blocks. The expense of solidifying the liquid would probably be suf- ficiently large so that any advantages accruing would be more than balanced by disadvantages of some moment. When one considers that all motor vehicles now in use are fitted to burn liquid gasoline the diffi- culty experienced in attempting to put the solid fuel on the market, even if it was cheaper than the liquid form, will be readily understood. Principles of Carburetion Outlined. The process of carburetion is combining the volatile vapors which evaporate from the hydrocarbon liquids with certain proportions of air to form an inflammable gas. The quantities of air needed vary with different liquids and some mixtures burn quicker than do other combinations of air and vapor. Combustion is simply burning and it may be rapid, moderate, or slow. Mixtures of gasoline and air burn quickly, in fact, the combus- tion is so rapid that it is instantaneous and we obtain what is com- The Modern Gasoline Automobile 273 monly termed an " explosion." Therefore the explosion of gas in the automobile engine cylinder which produces the power is really a com- bination of chemical elements which produce heat. If the gasoline mixture is not properly proportioned the rate of burning will vary, and if the mixture is either too rich or too weak the power of the explosion is reduced and the amount of power applied to the piston is decreased proportionately. In determining the proper proportions of gasoline and air, one must take the chemical composi- tion of gasoline into account. The ordinary liquid used for fuel is said to contain about eighty-four per cent carbon and sixteen per cent hydrogen. Air is composed of oxygen and nitrogen and the former has a great affinity, or combining power, with the two constituents of hydrocarbon liquids. Therefore, what we call an explosion is merely an indication that oxygen in the air has combined with the carbon and hydrogen of the gasoline. In figuring the proper volume of air to mix with a given quantity of fuel, one takes into account the fact that one pound of hydrogen requires eight pounds of oxygen to burn it, and one pound of carbon needs two and one third pounds of oxygen to insure its combustion. Air is composed of one part of oxygen to three and one half portions of nitrogen by weight. Therefore for each pound of oxygen one needs to burn hydrogen or carbon four and one half pounds of air must be allowed. To insure combustion of one pound of gasoline which is com- posed of hydrogen and carbon we must furnish about ten pounds of air to burn the carbon and about six pounds of air to insure combustion of hydrogen, the other component of gasoline. This means that to burn one pound of gasoline one must provide about sixteen pounds of air. While one does not usually consider air as having much weight at a temperature of sixty-two degrees Fahrenheit, about fourteen cubic feet of air will weigh a pound, and to burn a pound of gasoline one would require about two hundred cubic feet of air. This amount will provide for combustion theoretically, but it is common practice to allow twice this amount because the element nitrogen, which is the main constituent of air, is an inert gas and instead of aiding combus- tion it acts as a deterrent of burning. In order to be explosive, gaso- line vapor must be combined with definite quantities of air. Mixtures that are rich in gasoline ignite quicker than those which have more 274 The Modern Gasoline Automobile air, but these are only suitable when starting or when running slowly, as a rich mixture ignites much quicker than a weak mixture. The richer mixture of gasoline and air not only burns quicker but produces the most heat and the most effective pressure in pounds per square inch of piston top area. The amount of compression of the charge before ignition also has material bearing on the force of the explosion. The higher the degree of compression the greater the force exerted by the rapid combustion of the gas. Mixtures varying from one part of gasoline vapor to four of air to others having one part of gasoline vapor to thirteen of air can be ignited, but the best results are obtained when the proportions are one to five or one to seven, as this mixture is the one that will produce the highest temperature, the quickest explosion, and the most pressure. What a Carburetor Should Do. While it is apparent that the chief function of a carbureting device is to mix hydrocarbon vapors with air to secure mixtures that will burn, there are a number of factors which must be considered before describing the principles of vapor- izing devices. Almost any device which permits a current of air to pass over or through a volatile liquid will produce a gas which will explode when compressed and ignited in the motor cylinder. Modern carburetors are not only called upon to supply certain quantities of gas, but these must deliver a mixture to the cylinders that is accurately pro- portioned and which will be of proper composition at all engine speeds. Flexible control of the engine is sought by varying the engine speed by regulating the supply of gas to the cylinders. The power plant should run from its lowest to its highest speed without any irregularity in torque, i. e., the acceleration should be gradual rather than spasmodic. As the degree of compression will vary in value with the amount of throttle opening the conditions necessary to obtain maximum power differ with varying engine speeds. When the throt- tle is barely opened the engine speed is low and the gas must be richer in fuel than when the throttle is wide open and the engine speed high. Wlien an engine is turning over slowly the compression has low value and the conditions are not so favorable to rapid combustion as when the compression is high. At high engine speeds the gas velocity through the intake piping is higher than at low speeds, and regular The Modern Gasoline Automobile 275 engine action is not so apt to be disturbed by condensation of liquid fuel in the manifold due to excessively rich mixture or a superabund- ance of liquid in the stream of carbureted air. Carburetor Das Fig. 132. Illustrating Method of Storing Fuel in Brush Runabout, which Permits Short and Direct Gasoline Piping. Liquid Fuel Storage and Supply. The problem of gasoline storage and method of supplying the carburetor is one that is determined solely by design of the car. While the object of designers should be to 276 The Modern Gasoline Automobile Tank Fig. 133. Defining the Usual Methods of Fuel Storage in Motor Cars. A Oval Tank Back of Seat. B Round Tank at Rear of Chassis, Common on Rac- ing Cars. C Container Under Front Seat, the Conventional Method. D Tank at Rear of Frame, Underslung, which Makes Pressure-Feed Neces- sary. The Modern Gasoline Automobile 277 supply the fuel to the carburetor by as simple means as possible the iticl supply system of some cars is quite complex. The first point to consider is the location of the gasoline tank. This depends upon the amount of fuel needed and the space available in the car. A very simple and compact fuel supply system is shown at Fig. 132, which represents a plan view of the motor compartment of the Brush Runabout. The power plant in this little car is a single-cylin- der engine of comparatively low power and correspondingly low fuel consumption. As it does not require much gasoline to run a small engine one can obtain a satisfactory touring radius on one filling of a comparatively small tank. In this instance the fuel container is suspended from the dashboard and is placed immediately back of the engine cylinder. The carburetor which is carried as indicated is joined to the tank by a short piece of copper tubing. This is the simplest possible form of fuel supply system. As the sizes of cars increase and the power plant capacities aug- ment it is necessary to use more fuel, and to obtain a satisfactory touring radius without frequent stops for filling the fuel tank it is necessary to supply large containers. The principal methods of carry- ing fuel are depicted at Fig. 133. At A the tank is placed back of the seats and is oval in shape. It can be easily filled, and is carried high enough above the carburetor so that the fuel will run from the tank by gravity. The tank shown at B is a cylindrical form of large eapacit}', and is mounted at the extreme rear end of the chassis. This member also is mounted high enough above the carburetor so the gaso- line will flow to it by gravity. In some touring cars sufficient space is provided for the recep- tion of a fair-sized tank under the front seats, as shown at C. In this the tank is rectangular and is placed on suitable channel members so it can be supported on top of the frame. When a very powerful power plant is fitted, as on touring cars of high capacity, it is neces- sary to carry large quantities of gasoline. With the latest forms of bodies with low seats it is very difficult to find space enough for the placing of an adequately large tank. The usual method is depicted at D. In this the large fuel container is carried under the frame members at the extreme rear of the chassis. When installed in this manner it is necessary to force fuel out of the tank by air pressure or If 1 t.? t i -i I * jy- jyti 5 1 \>=tf 278 The Modern Gasoline Automobile 279 to pump it because the gasoline tank is lower than the carburetor it supplies. A typical fuel system in which the tank is placed under the seat, as depicted at Fig. 133, A, is shown in detail at Fig. 134. The carbu- retor is shown in section and is attached to the cylinders by means of a " T " form built-up manifold. The gasoline tank is joined to a filter by a short length of pipe and after the liquid passes through the filter it goes to the carburetor through a suitable length of brass or copper tubing. The filter is an important little device which removes any water, sediment, or other foreign matter from the fuel before it reaches the float chamber of the carburetor. Mixing Chambe O let Manifold " -7 Supply Chamber From Pump to Carburetor rainer Main Fuel Container Priming Pipe Hand Pump Fig. 135. Unconventional System in which a Pump is Depended Upon to Draw Fuel from Container and Deliver It to Vaporizer. The fuel system shown at Fig. 135 shows how the gasoline may be raised to the carburetor when the tank is placed at the rear of the iiassis, as shown at Fig. 133, D. A gear-driven plunger pump takes the fuel from the tank through the suction pipe and delivers it to the supply bowl of the carburetor, which it fills to a height determined by an overflow tube. When the liquid in the supply compartment of the carburetor exceeds the predetermined level it returns to the tank 280 The Modern Gasoline Automobile through an overflow pipe. Two pumps are provided, one worked by the engine, the other manually operated. The hand pump is used in emergencies, such as for priming the carburetor or for regular supply of fuel in case of failure of the main pump. The most common method of supplying gasoline to the carburetor when the tank is carried so low that the fuel will not flow by its weight is to pump air or gas into the supply tank and displace the gasoline "by its pressure. From the main supply tank the fuel goes to a small auxiliary tank carried on the dash of the power-plant compartment. A short pipe connects this small container with the carburetor, and as this auxiliary tank is higher than the mixing device the fuel will flow by gravity. If the gasoline under pressure was fed directly to the carburetor it might result in an oversupply of fuel because there might exist pressure enough to force the gasoline into the float cham- ber because the shut-off needle valve would not seat positively. The auxiliary tank is generally provided with some form of automatic cut- off mechanism, which interrupts the fuel supply when the small con- tainer is nearly full. Early Vaporizer Forms. The early types of carbureting devices were very crude and cumbersome, and the mixture of gasoline vapor and air was accomplished in three ways. The air stream was passed over the surface of the liquid itself, through loosely placed absorbent material saturated with liquid, or directly through the fuel. The first type is known as the surface carburetor and is now practically obso- lete. The second form is called the " wick " carburetor because the air stream was passed over or through saturated wicking. The third form was known as a " bubbling " carburetor. The illustrations at Fig. 136 show the principles of operation of two of the earliest forms of carbureting devices that were applied to change liquid gasoline into an explosive vapor. That shown at A consisted of a large cylinder divided into three parts by sheet metal partitions. The upper one was utilized as a fuel compartment, and this was joined to the main tank by suitable piping. The center compartment was gas storage space, and was divided from the bottom chamber by two perforated baffle plates. The lower portion of the cylinder was filled with wicking. This wicking was kept saturated with gasoline supplied from the up- permost compartment through a pipe which directed the stream of The Modern Gasoline Automobile 281 liquid against the center of the top baffle plate. As this member was provided with a large number of holes the gasoline was divided into a number of fine streams and the entire mass of wicking was saturated. Fig. 136. First Forms of Gasoline Vaporizers. A An Early Wick Carburetor. E Type in which Air is Drawn Through Fuel to Charge It with Explosive Vapor. When the piston of the motor went down on its suction stroke air was drawn in through the air pipe at the bottom of the vaporizing device and into the center compartment or gas chamber through the wicking. In passing through this saturated material the air became charged with gasoline vapor and the resulting gas was supplied to the cylinder through the mixture pipe. This method of vaporizing the gasoline produced mixtures extremely rich in fuel and in order to burn these successfully, a simple form of valve which permitted a certain amount of pure air to enter the cylinder and dilute the rich charge was provided in the mixture pipe. The carburetor shown at B is known as the " filtering" or "bub- bling " type. This consists of two chambers : one to hold the fuel, the 282 The Modern Gasoline Automobile other utilized as a gas storage or mixing chamber. A telescopic air pipe is needed, one portion fixed to the tank, the other, or sliding mem- ber, is carried by a float which maintains a certain definite distance between a deflector plate on the pipe and the surface of the liquid. The air enters through the air tube at the top, passes down under the surface of the gasoline, and is saturated with fuel particles. The rich gas flows into the mixing chamber through screens of wire gauze and after mixing with air entering through the auxiliary air regulator, the gas passes from the mixing chamber to the engine cylinder through suitable piping. While these primitive forms gave fairly good results with the early slow-speed engines and the high grade, or very volatile, gasoline which was first used for fuel, they would be entirely unsuitable for present forms of engines because they would not carburate the lower grades of gasoline which are used to-day, and would not supply the modern high-speed engines with gas of the proper consistency fast enough even if they did not have to use very volatile gasoline. The form of carburetor used at the present time operates on a different principle. These devices are known as " spraying carburetors/' The fuel is re- duced to a spray by the suction effect of the entering air stream draw- ing it through a fine opening. The advantage of this construction is that a more thorough amal- gamation of the gasoline and air particles is obtained. With the ear- lier types previously considered the air would combine with only the more volatile elements, leaving the heavier constituents in the tank. As the fuel became stale it was difficult to vaporize it, and it had to be drained off and fresh fuel provided before the proper mixture would be produced. It will be evident that when the fuel is sprayed into the air stream, all the fuel will be used up and the heavier portions of the gasoline will be taken into the cylinder and vaporized just as well as the more volatile vapors. The simplest form of spray carburetor is that shown at Fig. 137. In this the gasoline opening through which the fuel is sprayed into the entering air stream is closed by the spring-controlled mushroom valve which regulates the main air opening as well. When the engine draws in a charge of air it unseats the valve and at the same time the air flowing around it is saturated with gasoline particles through the gaso- The Modern Gasoline Automobile 283 line opening. The mixture thus formed goes to the engine through the mixture passage. Two methods of varying the fuel proportions are provided. One of these consists of a needle valve to regulate the amount of gasoline, the other is a knurled screw which controls the amount of air by limiting the lift of the jump valve. Jump Value Adjustment Mixture Passage Fig. 137. Marine-Type Mixing Valve, by which Gasoline is Sprayed into Air Stream Through Small Opening in Air-Valve Seat. While practically all modern motor cars use spraying carburetors having automatic fuel regulation, in rare cases one sometimes finds the earlier forms of carburetors used in improved and modified types. The wick carburetor, shown at Fig. 138, is that used on Lanchester (English) cars. In this the gasoline is taken from the main tank by means of a pump and forced up through the delivery pipe into a com- 284 The Modern Gasoline Automobile partment in which a number of wicks are placed. The fuel is main- tained to a certain level by means of an overflow pipe which returns any excess to the tank. The entering air stream which is taken from a jacket around the exhaust pipe and thoroughly heated passes through the wicks and becomes thoroughly saturated with gasoline. It is well mixed with the liquid vapors by passing through screens which sepa- rate the wick compartment from the mixture pipes. An auxiliary air pipe and valve are provided to dilute the rich gas before it passes into the motor through the usual form of inlet manifold. Auxiliary Air Wire Scree Gas Chamber 'Pump Piston Fig. 138. Lanchester Wick Feed Carburetor. The Only Modem Adaption of Earlier Forms. This is the only instance at the present time to the writer's knowledge where the earlier forms of carburetors have survived. One still finds many vaporizer valves, as shown at Fig. 137, used in marine installations, though there is a growing tendency at the present time to use more modern spraying carburetors in this field as well. Development of Float-Feed Carburetor. The modern form of spraying carburetor is provided" with two chambers, one a mixing The Modern Gasoline Automobile 285 chamber through which the air stream passes and mixes with a gaso- line spray, the other a float chamber in which a constant level of fuel is maintained by simple mechanism. A jet or standpipe is used in the mixing chamber to spray the fuel through and the object of the float is to maintain the fuel level to such a point that it will not overflow the jet when the motor is not drawing in a charge of gas. With the simple forms of generator valve in which the gasoline opening is con- trolled by the air valve, a leak anywhere in either valve or valve seat Will allow the gasoline to flow continuously whether the engine is drawing in a charge or not. The liquid fuel collects around the air opening, and when the engine inspires a charge it is saturated with _ra>oline globules and is excessively rich. With a float-feed construc- tion, which maintains a constant level of gasoline at the right height in the standpipe, liquid fuel will only be supplied when drawn out of the jet by the suction effect of the entering air stream. The first form of spraying carburetor ever applied successfully ivas evolved by Maybach for use on one of the earliest Daimler engines. The general principles of operation of this pioneer float-feed carbu- retor are shown at Fig. 139, A. The mixing chamber and valve cham- oer were one and the standpipe or jet protruded into the mixing cham- oer. It was connected to the float compartment by a pipe. The fuel [Tom the tank entered the top of the float compartment and the Qpen- ng was closed by a needle valve carried on top of a hollow metal float. When the level of gasoline in the float chamber was lowered the float tfould fall and the needle valve uncover the opening. This would Derm it the gasoline from the tank to flow into the float chamber, and is the chamber filled the float would rise until the proper level had >een reached, under which conditions the float would shut off the gaso- ine opening. On every suction stroke of the engine the inlet valve, vhich was an automatic type, would leave its seat and a stream of air vould be drawn through the air opening and around the standpipe or et. This would cause the gasoline to spray out of the tube and mix vith the entering air stream. The form shown at B was a modification of Maybach's simple levice and was first used on the Phoenix-Daimler engines. Several mprovements are noted in this device. First, the carburetor was nade one unit by casting the float and mixing chambers together in- 286 The Modern Gasoline Automobile 287 stead of making them separate and joining them by a pipe, as shown j at A. The float construction was improved and the gasoline shut-off valve was operated through leverage instead of being directly fastened to the float. The spray nozzle was surrounded by a choke tube which concentrated the air stream around it and made for more rapid air flow at low engine speeds. A conical piece was placed over the jet to break up the entering spray into a mist and insure more intimate admixture of air and gasoline. The air opening was provided with ] an air cone which had a shutter controlling the opening so that the ; amount of air entering could be regulated and thus vary the mixture proportions within certain limits. The form shown at B has been further improved, and the type shown at C is representative of modern practice. In this the float i chamber and mixing chamber are concentric. A balanced float . mechanism which insures steadiness of feed is used, the gasoline jet j or standpipe is provided with a needle valve to vary the amount of gasoline supplied the mixture and two air openings are provided. The :( main air port is at the bottom of the vaporizer, while an auxiliary air inlet is provided at the side of the mixing chamber. There are two methods of controlling the mixture proportions in this form of carburetor. One may regulate the gasoline needle or adjust the auxiliary air valve. A full description of the modern types of carbu- retors will be given in proper sequence. Elements of Carburetor Design. The design of the components of modern carburetors differ largely, but most of the modern mixing devices operate on the same general principle. Certain features of design have been accepted generally, such as automatic mixture com- pensation by auxiliary air valves, Yenturi type of mixing chamber, float and mixing chamber concentric, separate adjustment for gaso- line and air, and simplicity of construction. Automatic compensation is made necessary because a satisfactory mixture must be furnished at all engine speeds without the operator constantly varying the fuel supply or air proportions to allow for : different conditions of operation produced by varying speeds. On early types of carburetors it was necessary to constantly vary the mix- ture proportions by working the air shutter or fuel valve from the driver's seat while the vehicle was in motion. The aim was to secure 288 The Modern Gasoline Automobile a mixture that was best adapted to the conditions of operation then present, and while a skillful driver would manipulate the adjustments in a way to deliver well-proportioned mixtures to the cylinder the average operator did not control the mixture exactly and the results obtained did not make for efficiency. The writer has described the process of carburetion, and it is evi- dent that the gas is supplied the cylinder by the pumping effect of the piston. The velocity of the entering gases depends upon engine speed, and as the draught diminishes it will not pick up as much fuel as when it is traveling at a higher rate. The present type of compen- sating carburetor provides for a sufficiently rapid flow of gas at low speed by constricting the mixing-chamber bore at the spray nozzle so that the gas speed will be sufficiently high when the engine is pump- ing slowly. The reduced diameter of the mixing chamber increases the velocity of the gases because the cylinder must be filled through a smaller hole in a certain unit of time than would be the case if the bore were larger. Therefore to insure a full supply reaching the cylinder the gases must pass the top of the jet at a high rate of speed even if the piston is working slowly. As the opening is con- stricted not enough air will be drawn in at high speed, and it is neces- sary to supply it through an auxiliary opening usually controlled by some automatic form of valve. This can be adjusted to open only when the suction effect is sufficiently high to overcome the tension of the spring which holds the valve to the seat, and this increased suc- tion effect obtains only at high speeds. The Venturi type of mixing chamber is one which is being widely used at the present time because it has properties when properly pro- portioned of insuring high gas velocity at low engine speed. Special care must be taken in the proportions of the air passage, as it is neces- sary that the area be large enough to allow the air stream to pass through freely, yet at the same time it must be constricted to such a point that the entering air stream will pass the top of a standpipe with sufficient momentum to draw an adequate supply of gasoline from the spray nozzle. The velocity of the air stream has been vari- ously estimated, but most authorities are agreed that it should be from 7,000 to 9,000 feet per minute to insure picking up a sufficient amount of liquid as it passes around the spray nozzle. The Modern Gasoline Automobile 289 If one compares the carburetors shown at Fig. 139, B and C, one will find that there may be two distinct forms. In that shown at B the mixing chamber is set to one side of the float compartment while at C the mixing chamber is concentric with the compartment in which the float is carried. The reason for putting the mixing chamber in the center of the float is to insure a constant level of fuel in the stand- pipe regardless of the way the carburetor is tipped. With a mixing device having two chambers, as shown at B, the level in the float compartment and the spray nozzle will be at the same height only when the carburetor is on the level. In ascending or descending hills cither the float chamber will be higher than the mixing chamber or the reverse conditions obtain. At such times that the mixing chamber is higher than the float container fhe level of fuel in the jet will be lower than it should be. If, at the other hand, the float chamber is higher than the jet the fuel will overflow and the mixture will be excessively rich. With a carburetor constructed as depicted at C, the spray nozzle is at a central point and the level will not vary appreciably if the carburetor tilts one way or the other. This insures an even gas supply which in turn produces uniform motor action. The engine is not alternately starved or flooded, and the mixture proportions remain practically the same. In most cases carburetor designers believe it desirable to incorpo- rate separate adjustments for gasoline and air, in order that all tem- perature variations be compensated for. When an automatic air valve is provided and the spray-nozzle opening is controlled by a needle valve it is possible to obtain a wide variety of mixtures. With this form of construction two adjustments are provided which may be used separately or worked in unison as conditions demand. Gas mix- tures having proportions best adapted for low and medium speeds are usually obtained by regulating the gasoline valve, while the best high- speed adjustments are secured by altering the tension of the valve spring which regulates the air supply by restricting or increasing the lift of the air valve. Mixing Chamber Forms Commonly Used. One of the most impor- tant points to be considered is to provide a mixing chamber of such form that a direct passage will be provided for the charge to enter the 290 The Modern Gasoline Automobile cylinder. Any sharp angles or turns are apt to cause trouble because the gas speed will be retarded and an opportunity afforded for the condensation of fuel on sharp corners. A number of representative forms of mixing chambers are shown at Fig. 140. That at A has been very popular and the gradual curve permits the gases to flow easily. The spray nozzle is inserted at the point where the gases turn and there is no possibility of the entering air stream passing the gasoline supply pipe without picking up some fuel. Mixture Outlet Mixture Outlet Fig. 140. Showing Common Forms of Mixing Chambers and Spray Nozzle Locations. The form of mixing chamber shown at B is a preferred form, as the passage for the gas is direct to the engine pipes and there is no opportunity for the collection of liquids at any sharp corner. It is apparent that the diameter of the air-pipe bore is less around the spray nozzle than it is at the point above the gasoline 'supply jet. This gives a Venturi effect, which is known to produce automatic mix- ture variations. The Venturi tube construction is valuable because it insures high gas velocity at low engine speed. The theory of Venturi tube or constricted air passage can be easily understood if one considers the basic facts properly. When any fluid, either liquid or gaseous, passes through a tube the volume passing will be the same at all points if the bore of the pipe is constant. If gas flows through a pipe having a variable section the quantity of gas or liquid flowing through the tube remains the same, but the velocity is inversely proportional to the area of the section at different points. Therefore, if the air passage is contracted at a certain point the speed of the air stream will be greater where the area of the opening is The Modern Gasoline Automobile 291 A? will be evident the air passage is usually constricted at the spray nozzle for reasons previously outlined. In the form of mixing chamber shown at A no auxiliary air device i> provided, but in that depicted at B an auxiliary air valve is pro- vi< KM! at one side of the mixing chamber. The form of air passage i outlined at C is not as satisfactory as the simpler forms, which pro- vide for more direct gas flow. In this the entering air is forced to turn a sharp corner, and the resistance this offers will seriously retard the speed of the entering air stream. The form of mixing chamber outlined at B is that commonly used. Problem of Float-Bowl Design. Next in importance to the mixing chamber form is the problem of float-chamber design, and the mech- anism which regulates the height of the fuel in the spray nozzle should be as simple and as positive in action as possible. The float and nee- dle should be so arranged that the gasoline will be regulated in such a manner that as soon as the proper level is reached the gasoline ori- 1 fice should be shut off positively. If the mechanism is made simple it i- n<>t so likely to get out of order as when more complicated methods ' of valve operation are provided. The floats are made in two forms. They may be a hollow sheet- metal construction, or cork. When a hollow metal float is employed , care is taken to insure that it will be absolutely tight and that fuel cannot enter its interior. Cork floats are usually coated with a shellac varnish to minimize the danger of the cork absorbing fuel. The metal float is more expensive than the cork, and if it leaks it will fill with liquid and cause the carburetor to flood. The cork float may absorb sutlii-ient fuel to change its weight enough so that the gasoline level will be too high. It is also contended that particles may become de- tached from the cork float and enter the passage leading from the float compartment to the spray nozzle and clogging it or passing on | further and constricting the bore of the jet. The simplest form of float mechanism is depicted at Fig. 141, A. 1 1--!-.- the float is pivoted at one end and carries the needle at the other. The needle closes the gasoline orifice when the level of fuel is at the right height. As soon as the level falls the float drops and the needle valu- leaves its seat and permits gasoline to enter. When sufficient has been admitted to restore the level to the proper point the float 292 The Modern Gasoline Automobile rises and the gasoline opening is stopped up by the needle. The form shown at B is a modification of the simpler construction outlined at A. In this the fuel-supply needle is carried at the center of the cir- cular float instead of at one end. The disadvantage of these simple forms in which the gasoline enters at the top of the float chamber is Gasoline Entrance Weight Fig. 141. Types of Float Chambers in Common Use Defining Various Methods of Controlling Fuel-Supply Valve. that the weight of the entering fuel which falls on the float's surface prevents the float from rising as quickly as it should, and the fuel supply is not cut off until the level is somewhat higher than it should be. The form shown at C utilizes a hollow metal float which operates the shut-off needle through toggle linkage. As the float falls the lev- ers reverse the movement and the needle valve is lifted, this admitting The Modern Gasoline Automobile 293 fuel through the hole at the bottom of the float chamber. A balanced float construction is outlined at D. The needle-valve stem carries a \\viirlit which tends to keep it seated in a positive manner, and with this form of weighted valve one is not apt to have the erratic fuel supply that might be caused by vibration of power plant or road on tin- simpler forms depicted at A and B. The float is not balanced by the weight unless the level is at the proper height, and when the fuel level falls the weight of the float which is increased in value by the system of leverage raises the needle and weight. As in the previous case, shown at C, the function of the leverage is to reverse the direc- tion of movement. That is, the needle valve is raised from its seat when the float falls and is seated when the float rises. Gasoline Spray Nozzle Form Important. At Fig. 142 various forms of spray nozzles and auxiliary air valves are depicted. The simplest form is presented at A, this consisting of a standpipe having a single small hole at the top through which the fuel is discharged in a solid stream in much the same manner as water through a hose. On some foreign carburetors the standpipe is provided with a tapered plug, hav- ing series of grooves cut in its surface for the passage of fuel, as shown at B. The advantage of this construction is that the gasoline is atom- ized and is discharged in a number of fine streams instead of the coarser single stream. When the gasoline is discharged in a form of a mist it produces a much better mixture than when ejected in a single stream which must be broken up and divided into fine particles before it will form a homogeneous mixture. The disadvantage of the grooved i plug is that the fine passages are apt to become clogged from very small particles of foreign matter in the fuel. In fact, pieces of dirt which would pass out with the stream of gasoline from the nozzle shown at A will clog the fine passages of the plug shown at B. The amount of fuel delivered through the simple standpipe is regulated by the size of the hole, while the quantities of liquid sprayed from the nozzle shown at B can be varied to obtain different mixtures by changing the number of grooves in the plug seat. The spray noz- zles illustrated at C and D are forms in which the gasoline supply is regulated by a needle valve, that at C using an overhead valve, while that at D has the needle valve adjusted from the bottom. The former coii>truction is preferred when it is possible to apply it because it 294 The Modern Gasoline Automobile has a tendency to divide the stream of fuel into a spray or mist which is more easily vaporized. The spray nozzles shown at C and D are used more often than those depicted at A and B because of the ease with which the gasoline Grooved Plug Needle Value Fig. 142. Spray Nozzle Forms and Methods of Supplying Auxiliary Air to Modern Carburetors. proportions may be varied by screwing the needle in or out of its seat, thus reducing the size of the opening when one desires to diminish the amount of fuel or screwing it out and allowing more fuel to pass when richer mixtures are desired. Typical Auxiliary Air Valve Forms. Considerable difference of opinion exists in air valve construction as well, and many methods of admitting auxiliary air are used. The ordinary mushroom or poppet The Modern Gasoline Automobile 295 valves depicted at Fig. 142, E and F, are more widely applied. The former is a flat seat type kept seated by a compression spring while that at F is the ordinary form of automatic valve having a bevel seat, The disadvantage of a poppet valve is that its action is not regular, and it is apt to chatter or vibrate rapidly if the suction is not constant. Ball and reed valves have been applied on many forms of carbu- retors, and it is claimed for these that they will provide an increasing supply of air as the engine speed augments without chattering or fluctuation. When a series of openings are provided instead of one large port and each of the smaller holes is regulated by an individual reed or ball it is possible to so vary the strength of the reeds, or the weight of the ball, that the air supply will be progressive. When poppet valves are used it is customary to make these of leather or fiber so that they will not be noisy when they seat. The method defined at G is one in which reeds are used, three being pro- vided, so graduated in strength that one alone opens at medium speed, 'then the other two leave their seats progressively as the engine speed augments and the suction effect becomes greater. The various forms of spray nozzles and auxiliary valves commonly used will be further described in connection with the features of the leading types of vaporizers. Methods of Gas-Supply Regulation. The methods of regulating the amount of gas supplied the cylinder vary to some extent, though the general system is to introduce some form of butterfly or shutter valve in the mixture pipe between the mixing chamber and the valve chamber. These valves are operated by rod connection to hand lever placed on top of the steering post or accelerator pedal on foot boards, land the amount of gas passing from the carburetor into the cylinder ^depends upon the amount of opening provided by the valve. When it is fully opened the gas may fill the cylinders easily, though as its position changes the area of the mixture passage is gradually decreased and the amount of gas passing through reduced. In some cases the hand throttle is supplemented by an automatic ; governor which is designed to shut off the gas supply should the engine ; speed increase beyond a certain predetermined point. A carburetor fitted with both hand-operated throttle and shutter actuated by a governor from the engine is shown at Fig. 143. The hand throttle 296 The Modern Gasoline Automobile is a simple disk valve attached to a stem passing through the mixture pipe at a central point. When in the position shown the passage is fully opened. The governor throttle is a shutter valve placed in a special pocket above the hand-operated disk. It is worked by lever and rod connection by a centrifugal governor. The governor consists of two weights pivoted in such a manner that they lie close to the governor shaft when engine speeds are low. Governor Throttle- Hand Throttle Fig. 143. Showing Method of Regulating Fuel Mixture Supplied the Cylinders by Means of Centrifugal Governor, which Automatically Reduces the Quantity when Engine Speed Exceeds a Certain Predetermined Limit. As the speed of the governor shaft increases the weights tend to fly out from center due to centrifugal force, and as they are thrown out they pull a sliding collar back against a spring. The sliding collar actuates a lever which closes the governor-throttle valve by the rod connecting it to the governor. The governor is driven from the engine by some form of driving gear, or it may be located on the cam shaft. The amount the weights fly out is regulated by the spring, and as its ten- sion is increased it will take a higher engine speed to throw the weights out sufficiently to close the governor throttle. When the spring is weakened the governor weights fly out at lower speeds and the gov- ernor throttle is closed sooner. Such a device is useful in preventing racing of the engine under certain conditions. For instance, if the car was climbing a hill on one The Modern Gasoline Automobile 297 of the lower gear ratios which would permit the engine to run quite fast and the clutch pedal was depressed so that the drive would be momentarily interrupted, the tendency of the engine, thus relieved of its load, would be to run at an extremely high rate of speed. If the operator was fully occupied in steering and shifting gears he could not regulate the hand-throttle valve and the result would be that the engine would run dangerously fast. When a governor is fitted, as soon as the engine speed tends to become excessive the weights fly out and the supply of gas is diminished automatically. - A governor is also useful on commercial cars where it is desired to keep the vehicle speed within certain limits. As speed is directly dependent upon the number of engine revolutions, the governor can be set in such a way that the engine will run up to a certain point and no faster. Governors are not so widely used at the present time as they were in the past, owing to improvements in carburetor control devices. All governors do not operate on the centrifugal principle. Some are hydraulic, others are worked by compressed air. The fly ball governor described is the most common, and as it shows clearly the principle of action and utility of such devices there is no need of considering the other forms which are so rarely found. Construction of Modern Carburetors. As the gasoline used in for- eign countries is an imported product and is therefore more costly than it is in the United States, the foreign carburetors have been de- veloped with a main object in view of securing maximum fuel effi- ciency, and minimum fuel consumption is sought rather than greater flexibility. In this country conditions have been such that the eco- nomical aspect has been somewhat neglected because at the present time the cost of fuel is really one of the smallest items to be consid- ered in operating the average touring car. Carburetors of domestic development are not so susceptible to derangement as those of foreign derivation, but they are not so efficient and consume more fuel. The varying conditions to be met in the effort made to. secure power, gaso- line economy, and flexibility have resulted in a wide variety of instru- ments. It is apparent that these must operate on definite principles common to all, but at the same time considerable difference of opin- ion exists among designers and details of construction differ in almost all forms. 298 The Modern Gasoline Automobile The Schebler Model " E " carburetor is a concentric float type, and is one of the simplest and most satisfactory of the many forms that have received wide application. The primary air inlet is through an air bend at the bottom of the carburetor, as shown at Fig. 144, and an auxiliary air inlet controlled by the usual form of poppet valve is Air Value Spring. Leather Air Value Disc. Auxiliary Air Port Throttle Lever Loch Spring Loch Nut Air Value Adjust! 'crew Oas Outlet Primary Air Inlet Air Bend Reversible Union Ell Needle Valve Packing Nu Gasoline A djustingNeedle Valv Fig. 144. Schebler Carburetor Construction Outlined. This Is One of the Simplest Forms that Have Been Used Extensively. provided at the top of the mixing chamber. The spraying nozzle is inserted at an angle and the amount of fuel sprayed into the mixture is regulated by a gasoline-adjusting needle. The gasoline shut-off valve in the float chamber is operated through a lever fulcrumed at its central point, the float being attached at one end while the float- control valve is carried at the other. An upward movement of the The Modern Gasoline Automobile 299 float closes the valve, which is opened as the float falls. The gasoline needle is depended upon for varying the mixture for low speed, while the auxiliary air valve takes care of high-speed mixture adjustments. The Kingston device, which is shown in section at Fig. 145 with important parts clearly depicted, is similar in principle to that pre- Needle Value Loch Screw Throttle Lever 'ne Adjusting Screw Venturi Tube Auxiliary Air Ports Float Value Cap Cork Float Float Chamber Spraying Nozzle Pipe Connection Gasoline Inlet Needle Valve Fig. 145. Kingston Automatic Carburetor Admits Auxiliary Air Through Ball- Controlled Ports at Side of Mixing Chamber. viously described, inasmuch as it has a concentric float and mixing chamber and a lever-control float valve. The main air opening is through an air bend at the bottom of the carburetor, and the mixing chamber is constricted at the top of the spray nozzle to produce a Venturi tube effect. The auxiliary air ports are controlled by a series of balls of varying weight which open progressively as the motor suc- tion increases. Fuel regulation is by an overhead needle valve, while the amount of mixture passing to the cylinders through the gas outlet is regulated by a simple throttle disk which operates on the same 300 The Modern Gasoline Automobile principle as the damper of a stove pipe. This differs from the throttle arrangement of the carburetor shown at Fig. 144, as that member is composed of a movable plate which has an up-and-down motion instead of the oscillating motion of the damper form. The throttle of the former type is known as a " butterfly valve," while that shown at Fig. 144 is a simple shutter type. Throttle Disc Spraying Nozzle Auxiliary Air Port Float Valve Cap Air Value ir Value Spring f-vf /> Value Spring Adjusting Screw Air Value Lift Adjustment Primary Air Inlet Needle Value Packing Nut Gasoline Adjusting Needle Valve Fig. 146. Holley Carburetor with Spring-Controlled Poppet Valve to Regulate Auxiliary Air Passage. Another simple type of vaporizer which has given very good re- sults in practice is shown in section at Fig. 146. This is a concentric float design having the auxiliary air port closed by a flat-seated valve. The Modern Gasoline Automobile 301 The gasoline control member is a balanced valve having a counter- weight which tends to prevent vibration. The mixture proportions are regulated by a gasoline-adjusting needle valve at the bottom of the mrlmretor and the air valve spring tension adjustment. The mix- ture delivered to the cylinders of the motor is regulated by a simple form of throttle disk. A later and improved form of Holley Carburetor is shown in sec- tion at Fig. 147. In this the main air enters through a pipe at the side of the carburetor which communicates with an annular chamber surrounding the mixing tube. The gasoline collects in a small basin, at the top of the partition separating the float bowl from the mixing tube. The gasoline supply is regulated by the usual form of needle valve at the bottom of the float bowl. In this carburetor the only moving part is the float and the auxiliary air valve or auxiliary air openings have been eliminated by a special construction of the spray nox/le. Referring to the lettering on the drawing the action of this form of carburetor can be easily understood. The fuel from the tank enters the float chamber A to the gasoline filter screen B, and the level is regulated by the inlet valve C, which is actuated by the usual float and lever combination D. "When the motor is not running the level is halfway up the cup E and submerges the lower end of the low-speed tube F. When starting the engine the throttle G is nearly closed and gasoline and air are drawn through F with very high velocity owing to the degree of suction, thus forming a rich mixture and mak- ing starting easy. The tube F continues to supply the motor at low speeds, but as the throttle valve opens the small tube gradually emerges into the larger one and all the mixture supplied at motor speeds above 300 E. P. M. passes through the main mixing tube H. The spray nozzle I has a slot J which is supplied by two separate channels, the series of holes M and the plug L, the latter having a limited hole. At low engine speeds both operate, M predominating, but as the speed increases the fuel level automatically drops, because the needle C must lift higher with the increase in amount furnished. The leverage is about three to one, so that the float drop is three times the movement of the needle, and the holes M are uncovered to the atmosphere above the fuel surface, which passes through the slot J 302 The Modern Gasoline Automobile and maintains the uniformity of the mixture. The gasoline feed at low speeds is adjusted by the size of the plug opening 0, extreme high speeds by the area of the orifice in plug L, and the intermediate Fig. 147. Latest Model of Holley Carburetor with By-pass Tube to Provide Easier Starting. ratios through the automatic action provided by the series of holes M, the slot J and the nozzle I, and the adjusting needle. The advantages The Modern Gasoline Automobile 303 claimed by the designer are : permanent adjustment, positive starting, due to high vacuum and air velocity directly applied to the source of fuel supply; positive action at low and idling speed due to rich mix- ture ; greater economy and rapid acceleration, owing to more homo- geneous and better-proportioned vaporization. A richer mixture is automatically obtained for hill climbing and hard pulling because the fuel level rises with slower motor speed and feeds the spray nozzle through two channels instead of one. A typical foreign type of simple carburetor is shown at Fig. 148, this being the vaporizing device used on Mercedes cars. This is a float- Fig. 148. Mercedes Carburetor, which Has Retained Substantially the Same Form as when First Designed Nearly a Decade Ago. feed type having a float chamber carried at one side of the mixing chamber. The spray nozzle is a simple type which extends in a tube having one end open to the main supply pipe and the other to the 304 The Modern Gasoline Automobile annular chamber through which the air is inspired. The mixtui supply is regulated by a sliding throttle valve K, which also provid( the auxiliary air in increasing proportions as the amount supplied the cylinders is increased. The only way the gasoline proportions may be altered is by varying the spray nozzle or changing the level of the float. Fig. 149. Sectional View of Chapin Carburetor, which Has Mechanical Cont of Auxiliary Air Opening and Spray Nozzle Needle. The carburetor shown in section at Fig. 149 is a type which has auxiliary air valve, the auxiliary air opening being controlled by valve which is directly actuated by a mechanical connection between The Modern Gasoline Automobile 305 the throttle disk so that as the throttle is opened more air is allowed to flow through the auxiliary opening. The main air enters through the air bend at the bottom and passes around the spray nozzle, which is placed at the point of least area of the air tube. The amount of gasoline supplied the mixture is regulated by the fuel needle F, and this is raised by leverage from the throttle so that more fuel is sprayed into the mixture at higher motor speed. In other respects the carbu- retor is a conventional construction. The Excelsior carburetor, which is shown in section at Fig. 150, has several distinctive features, one of these being the floating ball Large Gear -Air Value Spring Tension Adjustment Fig. 150. Sectional View of Excelsior Carburetor. A Side Section Depicting Floating Ball Controlling Mixture Passage. B Showing Peculiar Air Valve Spring and Geared Control of Air Valve Stem. in the air tube and others exist in the peculiar form of auxiliary air- valve mechanism. It is claimed that the ball which rests against the pin D, shown in sectional view A, constricts the bore of the air tube at low speed so that the velocity of the air passing the spray nozzle is sufficiently high to insure taking up the proper amount of gasoline, but no more than that required to insure positive action of the engine. At highest engine speed the floating ball is drawn up against the stop 306 The Modern Gasoline Automobile pin D, and the air passage is practically free from any interruption. Under this condition the Venturi tube is permitted to exercise its function and a correspondingly large amount of gasoline is drawn from the spray nozzle. It is claimed that the floating ball controls the mixture automatically in that it permits the motor to get just the amount of gasoline it needs and thus conduces to economy. The auxiliary air valve is controlled by a clock spring the tension of which is multiplied by a series of gears. The tension is extremely light when the valve is closed and increases as the valve opens. It is claimed that this form of spring cannot vary and that it will main- tain its tension indefinitely. The air valve stem is provided with a spiral rack at one end which meshes with a small pinion controlled by the air valve spring. Any movement of the light air valve is multi- plied many times by the gearing so that the spring tension may be comparatively light. The carburetor is a concentric float type and with the exception of the floating ball in the air tube and the peculiar form of air-valve mechanism it does not differ from conventional practice. Referring to sectional view A at Fig. 150 the principle of action can be easily un- derstood. The fuel enters the float chamber F through connection TJ and a constant level is maintained by the float valve, which is directly actuated by the hollow metal float W. The primary air enters at P and is drawn by motor suction past the spray nozzle M located in the restricted portion of the Venturi tube. The amount of gasoline ad- mitted to the mixture is adjusted by the fuel-regulating needle G, while the amount of movement of the auxiliary air valve X may be controlled by the air valve spring tension adjustment shown in top sectional view at B. The mixture supplied to the cylinders is gov- erned by the usual form of disk throttle valve T. To insure easy starting the stop K may be turned so that the air valve is held closed, this making for strong suction through the restricted portion of the Venturi tube and insuring easy starting by providing a rich mixture. The carburetor shown at Fig. 151 is that used on Pierce cars, and is illustrated because it presents a number of novel features. While the construction in the main follows conventional practice inasmuch as the spray nozzle is concentric with the float, it employs a novel method of auxiliary air valve control and a form of throttle which is 307 308 The Modern Gasoline Automobile not generally used. The auxiliary air ports are regulated by reec which are backed by supplementary springs to prevent excessive mo- tion. The reeds open progressively as the suction increases. Tl throttle chamber contains a barrel-shaped throttle member which Water Water Inlet Water Outlet Pipe Connection Primary Air Inlet Fig. 152. Grouvelle and Arquemberg (French) Carburetor with Venturi Tx Mixing Chamber and Air Port Control by Floating Balls. openings cut in it registering with the gas outlet and the orifice cor municating with the mixing chamber. The gasoline supply is regu- lated by a needle valve which may be adjusted to regulate the size of the opening in the nozzle. The mixing chamber is water-jacketed, The Modern Gasoline Automobile 309 and as the stream of hot water from the engine is kept circulating through the water space the heat tends to promote more positive vaporization of fuel and insure thorough mixture of gasoline and air. The Grouvelle and Arquemberg carburetor depicted at Fig. 152 is a foreign type that has been applied with some degree of success in this country. The float chamber is carried to one side of the mixing chamber and the usual Yenturi tube construction is followed. No gasoline regulation is possible without changing the spraying nozzle, and as the auxiliary air supply is regulated by a series of ball valves this adjustment cannot be varied. The mixing chamber is water- jacketed and the amount of fuel admitted to the cylinders is regulated by a simple disk valve. It is advanced by the makers of this apparatus that once fitted to an engine it will need no further attention and is entirely automatic in its action. The combination of the Venturi tube and the floating ball auxiliary air control are said to provide mixtures of suitable proportions for all engine speeds without using adjustable members which are liable to get out of order and cause trouble. Another simple form of carburetor in which the Venturi tube effect is depended upon is shown at Fig. 153. In this device the car- buretor and induction pipe are a unit. The float chamber is carried to one side of the mixing chamber and the auxiliary air valve and throttle are located at the top of the air tube. The float chamber and spray nozzle construction are conventional, but the combined throttle and air valve construction is unique. The air valve is a light sheet metal member located at the extreme top of the mixing chamber and held to its seat by a cone-shaped helical spring. The air valve is guided by the throttle stem. The throttle consists of a cylindrical member connected to a hub by four ribs, and when it is desired to shut off the gas the lower portion of the throttle seats against the top of the air tube, thus effectively shutting off the branches which lead to the cylin- der from the central member. Owing to the small bore of the mixing chamber a rich gas is in- spired at low motor speeds, and when the suction effect increases the auxiliary air supply enters through the throttle and meets the incom- ing column of rich gas to dilute it sufficiently to obtain a properly proportioned mixture. The course of the gas is direct, rising verti- 310 The Modern Gasoline Automobile cally from the top of the spray nozzle to the throttle where it branches to the two inlet pipes forming the letter Y. Float Chamber X Metal Float Float Value Primary Air Inlet Qasollne Inlet "V Spraying Nozzle Fig. 163. Peerless Carburetor, which is Combined with Induction Manifold. Has Spray Nozzle and Float Chamber at Bottom and Air Valve at Top. The air tube is water- jacketed its full length to insure vaporization of comparatively low grade fuel. The main air entrance is through a The Modern Gasoline Automobile 311 funnel-shaped opening provided with a fine mesh screen, past a hinged shutter and then around the spray nozzle. The function of the shut- ter is to promote easy starting, as it may be dropped so the air pipe is almost shut off when it is desired to promote high gas velocity past the top of the spray nozzle. The mixture proportions are altered by changing the tension of the air valve spring which directly affects the degree of opening and the amount of auxiliary air inspired. A simple form of automatic carburetor is shown at Fig. 154. This utilizes a concentric mixing chamber of the Venturi tube type. The auxiliary air port is controlled by a flat seat valve and the gaso- line spray is regulated by an overhead needle adjusting tube. The air entrance through an air bend at the bottom of the carburetor flows past the spray nozzle and out through the gas outlet which is con- trolled by a butterfly throttle valve. A feature of this instrument is the detachable strangling tube which may be removed in case the proper adjustments cannot be obtained by the air valve and gasoline needle and replaced by one of larger or smaller bore as conditions demand. Multiple Nozzle Vaporizers. To secure properly proportioned mix- tures some carburetor designers have evolved forms in which two or more nozzles are used in a common mixing chamber. The usual con- struction is to use two, one having a small opening and placed in a small air tube and used only for low speeds, the other being placed in a larger air tube and having a slightly augmented bore so that it is employed on intermediate speeds. At high speeds both jets would be used in series. Some multiple jet carburetors could be considered as a series of these instruments each one being designed for certain con- ditions of engine action. They would vary from small size just suf- ficient to run the engine at low speed to others having sufficient capac- ity to furnish gas for the highest possible engine speed when used in conjunction with the smaller members which have been brought into service progressively as the engine speed has been augmented. The multiple nozzle carburetor differs from that in which a single spray tube is used only in the construction of the mixing chamber, as a common float bowl can be used to supply all spray pipes. It is com- mon practice to bring the jets into action progressively by some form of mechanical connection with the throttle or by automatic valves. 312 The Modern Gasoline Automobile 313 A simple form of multiple jet carburetor h shown at Fig. 155, this being an adaptation of the Stromberg carburetor. It does not differ materially from the single jet construction except that there is Needle Value Lift Lever, Gas Outlet Auxiliary Ga dine Needle Priming Lever Float Value Gasoline Inlet Wire Gauze Settling Chamber Nozzle Air Value Stem Auxiliary Jet Primary Air Inlet Primary Jet Drain Cock Fig. 166. Details of Stromberg Double-Jet Carburetor, which Provides Extra Fuel Through Auxiliary Spray Jet when Motor Demands It. an auxiliary nozzle which is closed by a spring-controlled auxiliary gasoline needle. This is operated by a, needle valve lift lever which in turn is affected only when the auxiliary air valve is drawn down, a certain distance by the motor suction. At low and intermediate speeds the mixture is supplied through the primary jet in the main mixing chamber. When the engine speed augments to such an extent that the auxiliary air valve is opened to a certain point the adjusting 314 The Modern Gasoline Automobile nut on the end of the valve stem bears against the long arm of the lever and lifts the auxiliary gasoline needle from its seat. More gaso- line is then sprayed into the mixture which has become too thin because of an oversupply of air through the auxiliary valve and proper mixture proportions are maintained. Fig. 156. Carburetor Incorporated in F. I. A. T. Cylinder Casting Is a Multiple- Jet Type Having Two Spray Tubes. The form shown at Fig. 156 is a novel one in several respects. It is the type where a common float bowl supplies both spray nozzles. The small nozzle A is used at low speeds and is brought into commu- nication with the throttle chamber C by a small port in the throttle The Modern Gasoline Automobile 315 shell. When the throttle is opened still further to secure higher speed of the motor the mixing nozzle B, which is a larger one, is brought into play and assists the nozzle A, which would be inadequate if used alone. The auxiliary air enters through the openings E which are also con- trolled by ports in the throttle shell. One of the most distinctive features of this carburetor is the manner in which it is incorporated with the cylinder unit casting, it being installed at a point between the pairs of the cylinders. The induction manifold is formed integral with the cylinder casting and no outside manifold is used or needed. The throttle assembly is formed as a unit and inserted into a suitably machined opening while the float chamber and spray nozzle assembly is inserted at the lower portion as another unit. A simple form of two-jet carburetor having an automatic control of the mixing chamber is shown in section at Fig. 157. In this a clack valve is used to close off the secondary mixing chamber at low speeds. All the air is drawn through a common opening and deliv- ered to an annular air chamber which surrounds the mixing chamber. This permits one air inlet to serve both primary and secondary mixing chambers. At low throttle openings only the primary nozzle is util- ized and the amount of gasoline supplied can be adjusted to a degree which will insure a mixture of such proportions as will produce steady running with minimum gasoline consumption. When the throttle is opened to increase engine speed the degree of suction is increased and at a time that the primary nozzle is not adequate to supply a full charge of gas the clack valve opens auto- matically and the secondary nozzle is brought into play. The valve is joined to a piston which works in a dashpot by means of a crank and connecting rod in order that its movement will be gradual. The coil spring back of the dashpot piston tends to keep the valve closed until the higher degree of vacuum or suction causes the valve to open against the spring resistance. If the throttle were suddenly closed the tendency of the valve might be to close very rapidly and to pre- vent too rapid movement of this member the piston is moved against an air cushion at the bottom of the dashpot cylinder. As this member must oscillate to a certain extent when the shutter works back and forth it is journaled at its lower end to permit a certain degree of movement. As will be evident both spray nozzles furnish mixture at The Modern Gasoline Automobile 317 high engine speeds. The view shown at A depicts clearly the con- struction of the clack valve and how its motion is controlled by the crank, connecting rod and piston in the dashpot cylinder. The view at B depicts clearly the arrangement of the float and mixing cham- bers, and the method of supplying both primary and secondary nozzles with air through one main air inlet and with gasoline from a common source. In the Zenith carburetor, which is shown at Fig. 158, a compound nozzle is used, this being composed of two jets designated as G and H. The center nozzle G is the main member and concentric with it is a tube which forms the compensating jet H. The inner nozzle com- municates with the float chamber through passages E and C, while the annular space between the main jet and the cap of the compen- sating member is supplied with gasoline by the passage F. At one side of the mixing chamber, and between that member and the float compartment, is a cylinder in which the secondary well P and the priming tube K are suspended. The upper end of the priming tube is in communication with th passage U in the mixing chamber walls. The passage U is controlled by the throttle T. When the throttle is closed the suction through the priming tube K is so great that it drains the gasoline from the secondary well and furnishes a very rich mixture through the opening U in the wall of the air tube D. The gasoline enters the secondary well P through the small hole Q at the bottom. With this vaporizer the quantity of air increases almost directly as the engine speed but the gasoline supply does not. Since the air supply increases with a constant ratio the amount of gasoline must be regulated to such proportions that a correct mixture will be obtained at all speeds. This is the function performed by the double nozzle because at low speed the outer or compensating nozzle lias a large quantity of fuel, but this decreases as the engine speed augments until at high speed the compensating nozzle does not add much fuel to the mixture. In this form the multiple nozzle construc- tion is employed to do away with the automatic air valve, all air being drawn through the primary air opening at the bottom of the mixing tube D. A strangling tube A is dropped into the air tube in order to constrict its area at the spray nozzle and secure a Venturi tube effect. 318 The Modern Gasoline Automobile The object of any multiple nozzle carburetor is to secure greater flexibility and endeavor to supply mixtures of proper proportions at all speeds of the engine. It should be stated, however, that while devices of this nature lend themselves readily to practical application Fig. 158. The Zenith Carburetor, which Embodies Novel Application of Double- Jet Principle, One Spray Nozzle Being Concentric with the Other. it is more difficult to adjust them than the simpler forms, having but one nozzle. When a number of jets are used the liability of clogging up the carburetor is increased, and if one or more of the nozzles is choked by a particle of dirt or water the resulting mixture trouble is The Modern Gasoline Automobile 319 difficult to detect. One of the nozzles may supply enough gasoline to permit the engine to run well at certain speeds and yet not be ade- quate to supply the proper amount of gas under other conditions. In adjusting a multiple jet carburetor in which the jets are pro- vided with gasoline regulating needles, it is customary tp consider each nozzle as a distinct carburetor and to regulate it to secure the best motor action at that throttle position which corresponds to the conditions under which the jet is brought into service. For instance, that supplied the primary mixing chamber should- be regulated with the throttle partly closed, while the auxiliary jet should be adjusted with the throttle fully opened. Utility of Gasoline Strainers. Many carburetors include a filter- ing screen at the point where the liquid enters the float chamber in order to keep dirt or any other foreign matter which may be present in the fuel from entering the float chamber. This is not general prac- tice, however, and the majority of vaporizers do not include a filter in their construction. It is very desirable that the dirt should be kept out of the carburetor because it may get under the float control fuel valve and cause flooding by keeping it raised from its seat. If it finds its way into the spray nozzle it may block the opening so that no gasoline will issue or may so constrict the passage that only very small quantities of fuel will be supplied the mixture. Where the carburetor itself is not provided with a filtering screen a simple filter is usually installed in the pipe line between the gasoline tank and the float oh amber. Some simple forms of filters and separators are shown at Fig. 159. That at A consists of a simple brass casting having a readily detach- able gauze screen and a settling chamber of sufficient capacity to allow the foreign matter to settle to the bottom from which it is drained out by a pet cock. Any water or dirt in the gasoline will settle to the bottom of the chamber, and as all fuel delivered to the carburetor must pass through the wire gauze screen it is not likely to contain impurities when it reaches the float chamber. The heavier particles, such as scale from the tank or dirt and even water, all of which have greater weight than the gasoline, will sink to the bottom of the cham- IT. whereas light particles, such as lint, will be prevented from flow- ing into the carburetor by the filtering screen. 320 The Modern Gasoline Automobile The filtering device shown at B is a larger appliance than that shown at A, and should be more efficient as a separator because the gasoline is forced to pass through three filtering screens before it reaches the carburetor. The gasoline enters the device shown at C Supporting Boss v To Carburetor Wire Gauze Mire Gauze Settling Chambe Settling Chamber Gasoline Tank To Carburetor Wire Gauze Settling Chamber Settling Chamber Fig. 159. Types of Strainers Interposed Between Vaporizer and Gasoline Tank to Prevent Water or Dirt Passing Into Carbureting Device. through a bent pipe which leads directly to the settling chamber and from thence through a wire gauze screen to the upper compartment which leads to the carburetor. The device shown at D is used on Chalmers motor cars and is a combination strainer, drain, and sedi- ment cup. The filtering screen is held in place by a spring and both The Modern Gasoline Automobile 321 are removed by taking out a plug at the bottom of the device. The shut-off valve at the top of the device is interposed between the sedi- ment cup and the carburetor. This separating device is incorporated with the gasoline tank and forms an integral part of the gasoline sup- ply system. The other types shown are designed to be interposed In 'tween the gasoline tank and the carburetor at any point in the pipe line where they may be conveniently placed. How Kerosene May be Utilized. The carburetion of kerosene seems to be partially solved at the present time, and. there are several forms of carbureting devices which permit one to utilize this fuel. It is important that the vaporizer employed be one that can be readily adapted to present day forms of motors. It is a fact that with lower grade fuels, as kerosene or benzol, a motor of lower compression than one can use successfully with gasoline and some means for heat- ing the entering mixture are needed. When kerosene is used as .fuel the conditions are similar to those which obtain with gasoline except the temperature at which vaporization commences. The heavier liquid requires more heat to cause it to vaporize, it being necessary to pre- heat kerosene to about two hundred degrees Fahrenheit before it will evaporate and form a mixture with air. It is necessary to provide a heated passage to further vaporize the mixture as it leaves the spray nozzle and as direct an entrance to the motor should be provided as possible. It is necessary to maintain a high velocity of the kerosene vapor in order to prevent condensation. The carburetor depicted at Fig. 160 is the Holley form adapted to use kerosene. It consists of a conventional form concentric jet, float- feed vaporizer, to which the kerosene is fed at the lower end and a mix- ing chamber having an auxiliary air valve is carried at the upper end of the device. In connection with this appliance a simple form of gasoline vaporizing valve is mounted at the upper end near the gas outlet, and is used to supply mixture enough to promote easy starting of the motor. The exhaust gases from the motor are passed through a jacket which surrounds the mixture tube leading from the kerosene vaporizer and which goes through the float bowl to heat the fuel therein. The liquid in the fuel container is heated to about two hundred degrees before it is sprayed in the motor, and it is contended that if 322 The Modern Gasoline Automobile kerosoie is kept near its boiling point it will leave the spray nozzle just as readily as gasoline will at ordinary temperature. It would be extremely difficult to start an engine on kerosene unless the vaporiz- Throttle Value. Air Valve Spring Exhaust Inlet Kerosene Inlet Primary Air Inlet Fig. 160. Holley Combined Gasoline and Kerosene Carburetor. May Be Used with Either Fuel, Though Specially Adapted for the Less Volatile Liquid Distillates of Petroleum, Because of Preheating Arrangement. The Modern Gasoline Automobile 323 ing device was raised in temperature to a point that would permit of ready vaporization of fuel. In the device shown at Fig. 160 if the motor is to be started cold the mixture supplied by the gasoline vapor- ixing valve is directed into the cylinder by a three-way valve which closes off the kerosene compartment and provides a by-pass for the gasoline mixture through the gas outlet. After the engine has run for a time, usually two or three minutes, the kerosene vaporizer ha? been raised in temperature to the proper point and a shift from one fuel to another is easily made by throwing the three-way valve over si i that the gasoline vaporizer is shut off from the gas outlet and direct communication is provided by the large opening in the throttle valve between the motor cylinder and the mixing chamber of the kerosene carburetor. When kerosene vapor is used with the usual type of induction manifold it is liable to condense if conditions are unfavorable to rapid Fig. 161. Combined Intake and Exhaust Manifold Suggested as Suitable for Use with Kerosene and Air Mixture. The Hot Exhaust Gases Heat the Inlet Pipe Walls and Produce More Complete Vaporization. volatilization. This "loading up" as it is called is due to the low velocity and temperature of the mixture which passes through com- paratively large passages, and while it can be reduced to a certain extent by making the area of the manifold cross section smaller, this is not desirable because at high speeds it would not be possible to supply an adequate amount of mixture to the cylinders unless the full cross section of the intake pipe is used. To minimize condensation the combination manifold shown at Fig. 161 lias been recommended. This consists of forming the intake and exhaust manifold in one 324 The Modern Gasoline Automobile easting, the thought being to heat the inlet manifold by the hot inert products of combustion to such a point that the kerosene vapor would be turned into a gas and all liquid particles vaporized. It is recom- mended that a manifold of this type be used in connection with the carburetor shown at Fig. 160. It is stated that the heated vapor from the kerosene vaporizer with its quota of air comprises about one fourth of the total volume of the charge, the balance of the air being supplied by the auxiliary valve at the top of the kerosene vaporizer. When the proper degree of com- pression obtains in the motor and the kerosene is properly heated before attempt is made to vaporize it the action of the carburetor de- scribed is claimed to be very similar to that of a gasoline vaporizer. It is claimed that it is possible to convert the usual gasoline motor by adding a spacer of proper thickness under the cylinder to reduce the compression to the point where kerosene can be used successfully. The degree of compression recommended as most suitable for use with kerosene vapor furnished by a carbureting device is between fifty and sixty pounds per square inch. Another important consideration is that the initial heating of the motor parts by use of gasoline gas be complete before one attempts to use kerosene. If the heavier liquid is supplied to the engine before the carburetor has been raised to the proper degree .of temperature, poor combustion of kerosene results and carbon deposits, or gummy residue is deposited in the interior of the combustion chamber. Supplying Kerosene by Direct Injection. The most logical method of utilizing fuels which have a low vaporizing point and which must be raised in temperature before they will give off vapor is to supply to the motor cylinder by direct injection. Several types of stationary power plants and some used in marine applications have been designed to use the cheaper fuels which cost less than gasoline, such as kerosene, benzol, or crude oil. The view at Fig. 162 is a section through a Detroit two-port two-cycle engine which has been adapted to use kero- sene by direct injection. The engine is of the conventional pattern, having an automatic inlet valve at the side of the crank case to admit air on the upward stroke of the piston. If this engine was used with gasoline the carburetor or mixing valve would be attached to this check valve cage and the engine would operate on the two-port principle. The Modern Gasoline Automobile 325 In the design under discussion the fuel supply device consists of a float feed arrangement attached to a spray nozzle placed in the trans- fer port in such a way that it discharges the fuel against the deflector Water Space Water Space Fig. 162. Showing Two-Cycle Motor with Device for Direct Injection of Heav- ier Petroleum Distillates into Cylinder. plate on the piston top. The float keeps the kerosene level in the float chamber to a height equal to the point of the spray jet. The amount of kerosene supplied can be regulated by the usual needle valve which controls the nozzle opening. 326 The Modern Gasoline Automobile Assume for the purpose of making the explanation clearer that tl cylinder is full of fresh gas and that the piston is traveling upward. It will close the transfer passage and the exhaust port and will com- press the charge above it. As the piston continues to move upward a vacuum is created in the crank case which draws in a current of air through the spring-controlled automatic valve P, and fuel into the fuel-feeding chamber. At the top of the compression stroke the gas is ignited by an electric spark and the resulting explosion causes a downward movement of the piston. As this member moves toward the end of its stroke the air in the crank case and the fuel-supply chamber is under compression. As the exhaust port is uncovered by the piston as it continues to go down the inert products of combus- tion, which have a pressure of forty to fifty pounds per square inch, stream out of the open port until but a very small portion of burned gas which is at atmospheric pressure remains at the cylinder. As the piston continues to move down it uncovers the spraying nozzle I. The compressed air in the crank case rushes into the cylin- der F and strikes the deflector H which directs it to the top of the cylinder and drives before it the remainder of the burned gases out of the open exhaust port. Simultaneously with this function the pres- sure in the fuel chamber B relieves itself by spraying a stream of fuel through the nozzle I. As this stream of liquid strikes the hot de- flector plate it is immediately vaporized, and as it is in the center of the incoming air stream it mixes with it to form an inflammable mixture. A disadvantage of this method of fuel injection is that it does not provide for the flexibility of engine action which is so essential in automobile service. This disadvantage does not militate against it to any great extent in stationary or marine application where the motor speed does not need to be varied within a wide range and where constant speeds are more often used. This method of auto- matic fuel injection is not practical when a four-cycle engine is used, and if fuel is to be suppled in this manner a small plunger pump driven by the engine is usually employed to- force it into the combus- tion chamber under considerable pressure. Intake Manifold Design and Construction. On four- and six-cylin- der engines and in fact on all multiple-cylinder forms, it is important The Modern Gasoline Automobile 327 that the piping leading from the carburetor to the cylinders be made in such a way that the various cylinders will receive their full quota of gas and that each cylinder will receive its charge at about the same point in the cycle of operations. In order to make the passages direct the bends should be as few as possible, and when curves are necessary they should be of large radius because an abrupt corner will not only impede gas flow but will tend to promote condensation of the fuel. Kvrry precaution should be taken with four- and six-cylinder engines to insure equitable gas distribution to the valve chambers if regular action of the power plant is desired. If the gas pipe has many turns and -angles it will be difficult to charge all cylinders properly. The problem of intake piping is simplified to some extent on block motors where the intake passage is cored in the cylinder casting and where but one short pipe is needed to join this passage to the carburetor. If the cylinders are cast in pairs a simple pipe of T or Y form can be used with success. When the engine is of a type using individual cylinder castings, especially in the six-cylinder power plants, the proper application and installation of suitable piping is a difficult problem. Intake piping is constructed in two ways, the most common method being to cast the manifold of brass or aluminum. The other method, which is more costly, is to use a built-up construction of cop- per or brass tubing with cast metal elbows and Y pieces. One of the disadvantages advanced against the cast manifold is that blowholes may exist which produce imperfect castings and which will cause mix- ture troubles because the entering gas from the carburetor, which may be of proper proportions, is diluted by the excess air which leaks in through the porous casting. Another factor of some moment is that the roughness of the walls have a certain amount of friction which tends to reduce the velocity of the gases, and when project- ing pieces are present, such as core wire or other points of metal, these tend to collect the drops of liquid fuel and thus promote con- densation. The advantage of the built-up construction is that the walls of the lubinj; are very smooth, and as the castings are small it is not difficult to clean them out thoroughly before they are incorporated in the manifold. The tubing and castings are joined together by hard sol- 328 The Modern Gasoline Automobile dering or brazing, and extreme care is needed to insure tight joints at all points. Some typical manifolds used on four-cylinder engines of various types are depicted at Fig. 163. That at A is composed of four pipes leading from a central member, each one communicating with an Fig. 163. Typical Induction Pipes Used on Four-Cylinder Motors. individual cylinder. The pipes are so nearly the same length that gas distribution is fairly uniform. The manifolds shown at B and C are substantially the same, except that one is a more pronounced Y than the other. Both are cast forms, that at B being of round section, while that at C is a square section casting. The manifold depicted at D is another type which has been evolved for use with a four-cylinder motor having individual cylinder castings. At E a cast manifold which is combined with a water-jacket cover plate used on the Chalmers block motor is illustrated, it being plain that the heating effect of the jacket-water tends to raise the tempera- The Modern Gasoline Automobile 329 ture of the entire manifold and promote more rapid vaporization if low-grade fuels are used. The manifold at' F is a type applied to a four-cylinder motor having cylinders cast in pairs, and this cast form has been made with graceful curves rather than straight lines. The induction pipe depicted at G is also utilized to supply a four-cylinder motor having twin cylinder castings and is made in the form of a letter T. At H a ramshorn type is outlined, the curves being reversed to the usual construction. The form at I is still another variation of the simple two-branch or T form of induction pipe. Fig. 164. Conventional Inlet Manifolds Adapted for Six-Cylinder Motors. When six-cylinder motors are used the problem is one that is not so easily solved, and designers show considerable ingenuity in devising manifolds to secure even charge distribution. A number of conven- tional forms that have received successful application are depicted at Fig. 164. All types shown except that outlined at D are used with six- cylinder engines having three pairs of cylinders, while that at D is employed when the motor is composed of two three-cylinder block castings. All the manifolds illustrated are built-up forms composed Additional matter relating to Induction Coil Action will be found on pages 774, 775, 776. 330 The Modern Gasoline Automobile of tubing and cast fittings with the exception of that outlined at C, which is a cast aluminum member. Another group of six-cylinder manifolds is given at Fig. 165. The forms at A, B, C, and E are designed for use with six-cylinder motors Fig. 165. Some Unconventional Forms of Gas Supply Pipes Used On Six-Cylin- der Power Plants. having individual cylinder castings. The form at A, while of peculiar shape, provides gas passages of about the same length leading to all cylinders. This is not true of those shown at B, C, and E, which are faulty in design, inasmuch as the gas will reach cylinders three and four much quicker than it will get to two and five, and to these two cylinders quicker than it will reach those on the extreme ends of the manifold, or one and six. It is claimed that the loop shown at B has given very satisfactory results, and that the peculiar construction compensates to a certain degree for the varying lengths of piping leading from the carburetor to the various valve chambers. The manifold at D is a built-up form utilized when cylinders are cast in pairs, and is much superior to that outlined at F, which is a cast aluminum member designed for the same type of motor. The Modern Gasoline Automobile 331 Compensating for Varying Atmospheric Conditions. The low- grade gasoline used at the present time makes it necessary to use vaporizers that are more susceptible to atmospheric variations than when higher grade and more volatile liquids are vaporized. Sudden temperature changes, sometimes being as much as forty degrees rise or fall in twelve hours, affect the mixture proportions to some extent, and not only changes in temperature but variations in altitude also have a bearing on mixture proportions by affecting both gasoline and air. As the temperature falls the specific gravity of the gasoline increases and it becomes heavier, this producing difficulty in vaporiz- ing. The tendency of very cold air is to condense gasoline instead of vaporizing it and therefore it is necessary to supply heated air to some carburetors to obtain proper mixtures during cold weather. In order that the gas mixtures will ignite properly the fuel must be vaporized and thoroughly mixed with the entering air either by heat or high velocity of the gases. A> it would be somewhat inconvenient to constantly regulate the avi-rage carburetor from day to day by the regular adjustments incor- porated in the device, forms of dash-controlled regulators have been devised. One of these is shown at Fig. 166 as applied to the Holley carburetor. It consists of a special form of valve interposed between the hot air connection around the exhaust manifold and the primary air entrance at the side of the carburetor. It is worked by a simple k-y and leverage connection. An indicator plate on the dash shows the different positions of the regulator. When the shutter is in the position shown at A only cold air is supplied the carburetor, this be- ing the proper position for summer running. When in the position shown at B the cold air slot is closed and only warm air which is taken from the jacket surrounding the exhaust pipe is supplied the car- buretor. This would be the proper position for cold or damp weather. If the shutter is placed as shown at C the air supplied the carburetor will be composed of both warm and cold currents in any desired proportion. When it is desired to exert a strong suction on the gasoline in the carburetor, as is often necessary in starting, the shutter may be turned as depicted at D in which case both air open- ings are shut off with the exception of but a very small slot. The equipment illustrated has been designed especially for use with the 332 The Modern Gasoline Automobile 333 Holley carburetor and is supplied by the manufacturers of that device. Air shutter regulation has been used on many cars, however, and has proved to be a very satisfactory way of compensating for extremes of temperature or altitude and variations in fuel quality. Disposition of Exhaust Gases. While the problem of getting the fresh gases into the cylinders is an important one the means of dis- posing of them after they have been burned is also important. The form of the exhaust manifold, which is usually a large malleable iron casting, is not so important as that of the induction pipe and the chief precaution to be observed is to make the passages in this mem- ber as large as possible and to proportion it in such a way that all parts of the casting will expand with the same ratio. An impor- tant condition to be observed, however, is the method of discharging the gases to the air and for this purpose various forms of mufflers, or silencers, are used so that the gases will be discharged in an un- objectionable manner. It has been demonstrated that the average motor vehicle engine cannot utilize the full expansive force of the burned charge because the exhaust valve is opened a certain number of degrees before the bottom center or before the piston reaches the end of its power stroke. This is done to give a lead or start to the gases and obtain higher engine speeds than would otherwise be possible. As a result of the early opening of the exhaust valve the gases will issue through the valve port at sufficient pressure to produce a report like a gun shot which would be apt to disturb persons and animals of nervous tem- perament and at the same time not be exactly music to the normal ear. It is not difficult to muffle the gases so there will be but little noise to the exhaust, but it is quite a problem to do it without producing back pressure in the muffling device that will cause serious loss of power. A muffler should offer minimum resistance to the passage of the gas and means should be provided for not only breaking the entering gas stream into smaller streams, but the capacity of the muffler should be sufficiently large so that the gases will expand to nearly atmospheric pressure before they are discharged into the air. Various forms of mufflers are shown in section at Fig. 167. The simplest, outlined at A, consists of a sheet metal shell having its ends closed by cast metal pieces. This has several times the volume of Inlet' Baffle Plates Fig. 167. Muffler Forms Adapted to Reduce Pressure of Exhaust Gases Before Discharging Them. 334 The Modern Gasoline Automobile 335 the cylinder and the gases expand to about atmospheric pressure be- fore they are discharged through the series of small holes at the bottom. The gas enters and leaves the muffler in streams indicated by the arrows. The objection to the use of small holes for breaking up the gas stream is that these are liable to clog with carbonaceous matter' from the interior of the engine, such as would result when excessive amounts of oil were used or from mud or clay from the road surface. The form shown at B consists of a number of concentric chambers which afford an excellent opportunity for the gas to expand to atmospheric pressure and to break it up thoroughly before it is dis- charred to the air. The exhaust gas enters the central pipe, passes out through a series of fairly large holes at its extremity into the middle compartment where it expands and passes out through another series of holes into the outer chamber. Here it again expands and finally leaves the muffler through a series of openings punched in the outer shell. The course of the gas may be easily followed by referring to the illustration, as it is indicated by arrows. A form employing a series of perforated baffle plates which divide the muffler body into eight compartments is shown at C. The function of the baffles is to break up the gas by making the gas streams follow a devious path through the first six chambers and expand into the seventh compartment, from which it passes to the eighth compartment through a series of fine holes in the last baffle plate of the series. The form at D consists of a central pipe member around which are placed thirteen pairs of stamped disks which form the same number of expansion chambers. The gas issues from the center pipe, where opportunity is given it to expand into the chambers provided by the disks which are merely placed in contact with each other at their edges and held together by moderate pressure. The force of the gas causes the disks to spring slightly at their edges and thus produce an annular discharge passage in each set of disks which insures thor- ough breaking up of the issuing gas stream. It is claimed that this method of construction provides a large amount of cooling surface and that the pressure of the gas is reduced just as much by the cooling effect as it is by the increase in volume permitted by the expansion chambers. 336 The Modern Gasoline Automobile The form shown at E is built on the ejector principle and is claimed to be particularly efficient, not only as relates to silencing qualities but also because back pressure is practically eliminated. The efficiency is due to its design, which allows that part of the gases which pass through the central pipe to do so with considerable force. This tends to produce a partial vacuum, which in turn promotes a ready expulsion of gas by drawing the main portion through the muffler rather than depend upon the upward stroke of the piston to clear both cylinder and muffler. This device is of the baffle plate type and the partitions are in the form of cones instead of the usual vertical or horizontal dividing walls because the conical form lends itself to the ejector principle better than the other types. \ \\\\\\\ Fig. 168. Water-Cooled Muffler Used when Exceptional Silence is Desired. Often Applied in Marine Service. A very good muffler for marine purposes is shown at Fig. 168. This consists of a double-expansion chamber and a water jacket. If the exhaust gases are cooled they will be considerably reduced in volume and pressure and for this reason water cooled forms are very quiet. As the gases are considerably reduced in pressure by the cool- ing effect one may use large holes for the passage of gas from one chamber to the other and the back pressure is correspondingly reduced. While a water cooled form of muffler can be readily adapted to marine service, it is not possible to use such on a motor car because of the large volumes of water which would have to be supplied to insure adequate cooling of the muffling device. The Modern Gasoline Automobile 337 It is sometimes possible to secure a more prompt discharge of the exhaust gases from the cylinder if a little attention is paid to the de- sign of the exhaust manifold. The form shown at Fig. 169 is a corn- Fig. 169. Suggested Exhaust Manifold in which Ejector Action of Exhaust Gases under High Velocity is Said to Reduce Back Pressure on Pistons. posite member consisting of four separate castings, the object of the arrangement being to secure an ejector effect by which the discharge from any one cylinder would tend to keep a condition of partial vacuum in the manifold and thus draw out the gases. The discharge from cylinder 1 goes through pipe A; that from cylinder 2, through member B, while the gases from cylinders 3 and 4 pass out through pipes C and D respectively. If the exhausts occur in the order 1, 2, 4, 3, it will be seen that the gases flowing through pipe A will pro- duce a certain suction effect in pipe B, which will tend to draw out the gases discharged from that cylinder when the exhaust valve opens. A manifold so constructed is but little more complicated than the ordinary construction, as it consists of the four bent tubes A, B, C and D, which are assembled together in such a manner that a portion of one projects into the other. The faster the engine works the more rapid the ejection of the gases and consequently the ejector action has a higher value at a time that it is needed .the most. Such a mani- fold would be more expensive than the conventional pattern, however, and there might be some difficulty in keeping it tight at the multi- plicity of joints. Utility of Cut-out Valve Explained. In order to take advantage of the gain in power which results when the gases are discharged directly into the air instead of being passed through the muffling device, many 338 The Modern Gasoline Automobile automobile makers provide a simple valve, which is called a " cut- out/"' between the exhaust manifold and the muffler. This is arranged in such a manner that when opened, the gases are free to issue directly to the air instead of passing through the muffling device, and as the back pressure incidental to the silencer is eliminated more power is obtained from the motor. A cut-out is also useful because it permits one familiar with gasoline motors to detect irregularity in engine operation by sound of the exhaust. A typical cut-out installation is shown at Fig. 170, this being more efficient than that commonlv used because even with the cut-out valve Main Muffle Fig. 170. How Muffler Cut-out Valve is Arranged on Wolseley (English) Cars to Reduce Noisy Direct Exhaust. opened the gases are silenced to a certain extent by being passed through the chamber P before they issue to the air. When the cut-out valve is closed the gases must follow a circuitous route through the muffler and by being broken up and allowed to expand issue to the The Modern Gasoline Automobile 339 air without appreciable noise. Whenever a cut-out valve is provided it is usually planned to open out so that any explosion of gas in the muffler which might result if the motor missed several explosions and then fired the gas in the silencer will tend to open the valve and relieve the excessive pressure in the muffling device. If some means were not provided to relieve the pressure, it might burst the muffler asunder. The average cut-out valve, therefore, performs three useful functions : First, it permits the exhaust gases to be discharged direct- ly to the air at such times that maximum motoi power is desired ; second, it provides audible indication of irregular engine action; third, it is a safety or relief valve to prevent excessive pressures from, damaging the muffler. Action of Kerosene Vaporizer Utilizing Water Spray. In order to insure proper combustion of kerosene when used in carburetors of the conventional form, it is necessary to start the engine on gaso- line, until all parts are thoroughly heated. If proper means are taken to heat the carburetor and the intake manifold to prevent con- densation of kerosene, it may be used just as soon as the various working parts have been properly heated. A float feed carburetor of conventional design arranged to burn kerosene is shown at Fig. 170a. It will be noted that the float chamber is surrounded by a jacket, through which hot water can enter at G and pass out at H, this heating all parts of the float chamber. The kerosene enters the device through the connection F and passes into the float chamber through the usual form of float-controlled valve. In the ordinary automatic carburetor, as the speed increases and the tendency is to draw in more fuel, an automatic air valve opens to admit an auxiliary supply of air to dilute the vapor. The carbu- retor illustrated utilizes the auxiliary valve in a different manner. The spray nozzle, instead of being the conventional form, is a small standpipe having numerous fine holes on one side and it is called a spray turret. At the bottom of the spray member the float bowl upper wall is shaped in such a way that a small pool of liquid fuel is allowed to collect in the bottom. The main air in- take is divided and is alone sufficient only to run the motor idle. The air that enters the primary intake passes directly over the pool of fuel and a rich mixture is obtained for starting on. The auxiliary 340 The Modern Gasoline Automobile Auxiliary Air Inlet ,GasOutlet Water Spray Hot Water Jacket Fuel Inlet Fig. 170a. Sectional View of Typical Kerosene Vaporizer Employing Water Spray to Insure Combustion of Kerosene Vapor. air enters through the opening D, and before it enters the cylinders it must pass the spray turret. This lifts the fuel up in the stand- pipe, where it is drawn through the small holes in the form of a spray. The greater the amount of air that is passing through, the higher the fuel rises in the spray turret, until with the throttle wide open it is sprayed from all the holes in the standpipe. The condition with a partially opened throttle is shown in sectional view and it will be noticed that the kerosene spray is coming through only the The Modern Gasoline Automobile 341 holes at the lower part of the standpipe. The amount of liquid sprayed into the mixture is regulated by the needle valve C. In order to burn kerosene successfully water is introduced into the mixture through the auxiliary spray nozzle I. This supplies an extra amount of oxygen and insures a more complete combustion of the kerosene vapor than would be the case if just air was used. The 1914 Holley Kerosene Carburetor. At this time a number of kerosene carburetors have been evolved and some have received practical application on various makes of cars. The carburetor shown at Fig. 170& is a late design by George M. Holley and is intended to be used in connection with kerosene after the motor has been started by means of the auxiliary gasoline vaporizer which is shown at Fig. 170c. Speaking of kerosene carburetors in general and the Holley device in particular, the inventor has offered the following facts : " As a commercial proposition, the four most striking features of the kerosene carburetor are : First, the low cost of fuel, which at present averages one-half as much as with gasoline. With a car using gasoline at the rate of one gallon per twenty miles, with gasoline costing 18 cents, the cost for fuel is .00 cent per mile. With a car using kerosene at the rate of one gallon for twenty miles, with kero- sene costing 9 cents, the cost of fuel is .43 cent per mile. This makes the fuel cost 52% lower with kerosene than with gasoline. Second, increased power, ranging in value from 5% to 8%. Third, a saving of about one-half in the amount of lubricating oil required, as kero- sene is itself a lubricant. Fourth, less spark-plug trouble on account of kerosene carbon being drier and finer than that deposited from the gasoline combustion. "Its two most serious deficiencies would seem to be the necessary use of two fuels, one sufficiently volatile to permit the motor to start when cold, and the other, or cheaper, for regular running after the engine has become heated. There is also the necessity, if a kerosene carburetor is applied to automobile motors already manufactured, of reducing the compression to 40 pounds to prevent knocking under extreme conditions. It requires but a few minutes' operation to heat an engine sufficiently on gasoline so the kerosene vaporizer may be used. The starting device which is shown at Fig. 173c consists 342 The Modern Gasoline Automobile of a floatless gasoline carburetor with a starvation type atomizing nozzle at one end. The device is controlled from the dash and works in connection with the kerosene carburetor, which is always in action. When starting, about 75% of the mixture supplied is gasoline vapor, and as the throttle of the kerosene carburetor is opened, as in driving a car, this proportion is decreased according to the throttle opening, Exhaust Gas Enters Here Float Shut off Valve Starting Tube Mixture Heating ' Tube Exhaust Gas Heating Chamber Main Spray Nozzle Main S Air Intake Regulating Fuel Needle Inlet Exhaust Gas Outlet Fig. 170b. The Holley Kerosene Vaporizer in Section. The Modern Gasoline Automobile 343 so that at driving speeds, even when starting from a standstill, 50% of the mixture is kerosene vapor and the balance gasoline gas. This starting device accomplishes two things, prompt starting and abso- lute prevention of smoking in starting. After the engine has been run for several minutes on the mixture of gasoline and kerosene vapor, the gasoline shut-off valve may be closed and the kerosene carburetor only employed to supply the mixture. "The kerosene carburetor is primarily a vaporizer, as the heat of the exhaust is utilized to convert atomized kerosene into a true vapor. The exhaust gas enters a jacket which is disposed around a spiral lixturePpe to Manifold Side Section Gasoline Container Gasoline Regulator Fig. 170c. Gasoline Carbureter Used in Connection with Holley Kerosene Vaporizer for Starting Purposes. mixture heating tube and is discharged to the air through a pipe having a number of fine holes at one end. In order to insure that only warm air will be 'taken into the mixture, the main air intakes are in a pipe which surrounds the exhaust pipe serving as an outlet from the exhaust gas jacket. The mechanism of the float is prac- tically the same as in a gasoline carburetor, as the float-controlled 344 The Modern Gasoline Automobile lever regulates the amount of fuel admitted so that a certain level is maintained at all times. When the engine is running with the throttle valve practically closed a rich mixture is supplied through a small auxiliary jet placed at one side of the main spray nozzle. As the throttle is opened the mixture from the main spray nozzle flows through the corrugated mixture heating tube, which is con- structed in that form so as to obtain the greatest possible heated sur- Induction Pipe Hot Water Pipe Gasoline Inlet Kerosene Inlet Mixture Heatinrf Tubes Sectional View Kerosene Spray Nozzle Fig. 170d. A Bi-Fuel Carbureter of English Design. face for a given length. An auxiliary air-valve is provided which surrounds the top of the mixture heating tube, which is closed on low throttle, but which opens to admit auxiliary air supply to the mixture as the suction increases. The amount of kerosene sprayed through the main nozzle may be adjusted by a regulating needle valve at the bottom of the carburetor. It is believed practical at the pres- The Modern Gasoline Automobile 345 ent time to equip any automobile with this type of kerosene car- buretor if the user does not object to handling an accessory in the form of a gasoline starter." The objectionable pounding which is present at certain times when kerosene is employed is considerably minimized by the use of the water spray, as in the device shown at Fig. 170a, or by admit- ting a small portion of the exhaust gases into the mixture through a by-pass from the exhaust pipes to the mixture pipes. It is claimed that either of these methods will eliminate the knocking sounds without lowering the compression and, consequently, the thermal efficiency of the motor. A form of carburetor which is being experimented with abroad is shown at Fig. 170^. This is known as the bi-fuel, because two independent float chambers and spray nozzles are provided, one being utilized for gasoline, the other for kerosene. In order to vaporize the heavy fuel mixture a portion of the hot water from the cylinder jacket is by-passed through a chamber in which the mixture heating tubes are placed as outlined in the sectional view. Two throttle valves of the spring-control poppet type are provided and are operated by means of an auxiliary lever or clack valve which is adapted to depress the throttles from their seats in order to permit the mixture to flow from the spray nozzle to the mixture heating tubes. Auxiliary air is admitted into the mixture by an oscillating shutter valve placed at the top of the carburetor just below the inlet manifold. A Camphor Vaporizer. Repeated attempts have been made in France to use camphor or naphthaline in the form of ordinary moth balls as a fuel for internal combustion engines. The first trials of this fuel date back over a decade, but it seems that the recent increase in the price of gasoline has revived interest in it, and new tests have recently been made. A form of vaporizer which has been submitted to tests at the laboratory of the Automobile Club of France is shown at Fig. 170e. There are two spray nozzles, one for the gasoline used for starting and the other for the liquefied camphor. The cam- pbor is vaporized by heat derived from the exhaust gapes which pass through a heating jacket or chamber adjacent to the camphor-mixing chamber. In all respects the vaporizer resembles an ordinary carbu- 346 The Modern Gasoline Automobile retor, as it has both primary and secondary air inlets. The camph is melted by contact with a separate coil heated by the exhaust and after being thus melted it flows to the spray nozzle through gauze strainer. After being sprayed from the spray nozzle the liquid comes in contact with the hot wall of the mixing chamber and is thereby gasified. It is claimed that in France camphor costs about 50 cents per hundred pounds when bought in large quantities. The test of the vaporizer was made with a two-cylinder taxicab. -The vehicle was first run over a macadam road with slight gradients and good surface for a distance of 32.5 miles out and the same distance Throttle Gasoline Spray Nozzle Camphor Spray Nozzle Heating Jacket Napthaline or Camphor Float Chamber Fig. 170e. Vaporizer of French Design Adapted for Use with Either Gasoline or Camphor Fuel. back again. This trip was made at an average speed of 22.5 miles per hour, the highest speed attained being 25 miles per hour. The entire distance was covered on camphor, the consumption being at the rate of substantially two miles per pound of camphor. At that rate the cost per hundred miles would be about 56 cents, as compared The Modern Gasoline Automobile 347 with $1.60 for gasoline at present French prices. The second test \\;i- made to determine the time required to heat up the engine suffi- ciently so it would run on the camphor vapor. It was ascertained that 13 minutes sufficed to heat up the engine and that when hot the power plant could be restarted directly on camphor after a stop not exceeding fifteen minutes. Stops of longer duration made it necessary to restart on gasoline. The Ford Gasoline Carburetor. Owing to the popularity of the Ford Automobile, which has been sold in very large numbers and which are in use in practically all parts of the world, it seems desir- able to illustrate the interior construction of one type of vaporizer used on these cars. This is a "puddle" type that is exceptionally NEEDLE VALVE LOCKING SCREW CHOKE AUXILIARY AIR DUCT KING SCREW USTING SCREW THROTTLE LEVER OVERFLOW TUBE TO ENGINE CORK FLOAT SPRAY NOZZLE DRAIN COCK Fig. 170f. Part Sectional View Showing Construction of One Type of Carburetor Used in Ford Cars. Additional matter pertaining to Magnetism, Magneto Principles and Operation will be found on page* ??(> to 789. 348 The Modern Gasoline Automobile simple in construction. The gasoline is admitted to the float bowl through the usual form of gasoline supply valve regulated by a cork float, which determines the proper level of fuel in the float chamber. The mixing chamber is a peculiar form, so designed that all air enter- ing through the main air intake must pass over the small pool of gasoline at the bottom of the mixing chamber before it can reach the engine. The amount of gasoline supplied the mixture may be varied by a regulating needle valve, and the amount of gas reaching the cylinders is controlled in the usual manner by a butterfly throttle valve. At low engine speeds, as when starting, the air cannot fail to pick up gasoline vapor no matter how slow it passes over the top of the spray nozzle. At higher speeds, when the mixture would be too rich, due to the high velocity of the air flow, a number of auxiliary air valves of the ball type open progressively as the suction increases and admit more air to the mixture to dilute it. The only adjustment possible on this device is by the needle valve, which may be locked in position when the proper adjustment has been reached by a suitable locking screw. The general details of construction may be clearly grasped by reference to illustration at Fig. 170/. The Muir Automatic Carburetor. A late addition to the already large carburetor field is the Muir single- jet automatic carburetor shown in section at Fig. 170^. The feature of this carburetor is the automatic regulation of the proportion of gasoline to air by the auxiliary air valve. The fuel is admitted to the float chamber in the usual manner and the float needle is controlled by a hollow metal float which regulates the level of fuel in the float chamber. The connection between the gasoline regulating needle which fits into the spray nozzle and the auxiliary air-valve stem is by means of a hard- ened steel pin which is permanently attached to the upper barrel portion of the needle and which is kept in constant contact with the cam on the end of the air-valve stem by a suitable compression spring. Any horizontal movement of the air-valve stem to the right, which occurs when the air valve opens through the suction of the engine, allows the pin to travel further up on account of the inclined work- ing face of the cam, and as this action permits the needle to rise slightly from the spray nozzle, the flow of gasoline is increased to correspond to the larger quantity of air admitted. The spray nozzle The Modern Gasoline Automobile 349 points diagonally into a restricted Venturi passage in the center of the float chamber. Adjustment of the needle valve is made by turning a screw at the head which is provided with a spring and ball ratchet lock which prevents any slackening after adjustment. Each notch in turning represents one-thousandth (.001") of an inch travel of the needle Air Valve Stem Mixture Outlet JKrottle "Disc Cam Flo&t eedle Choke VaJve Air Ber\d Fig. 170g. The Muir Carburetor with Mechanically Controlled Fuel Valve. point. The needle valve is provided with a cap, so that once the throttle adjustment has been attained for a certain engine the adjust- ment may be made permanent by sealing the cap. The whole claim for economical operation rests on the shape of the cam, and it is claimed that the proper shape for this member is obtained by actual experiment with the engine on a block test. To facilitate starting, 350 The Modern Gasoline Automobile Water-Jacket Mixture Outlet Throttle sc Glass Needle Valve Operating" Lever /Fuel Inlet 'Drain CocK Regulating Needle Fig. 170h. The Winton-Stromberg Carburetor Utilizes a Double Spray Nozzle. the main air bend or pipe is provided with a choke valve, which may be partially closed to provide for high air velocity at low engine speed. Another form of carburetor, in which the amount of gasoline drawn from the spray nozzle is increased as the throttle is opened, is shown at Fig. 170/t. A direct mechanical connection exists Between the throttle disk and the top of the spray nozzle. This is in the form of a bent wire which is adapted to move into the jet as The Modern Gasoline Automobile 351 the: throttle disk is opened. In starting, air is drawn through a small opening at the side of the mixing chamber and through a by-pass passage to a point in the outer spray nozzle which will insure that a sufficiency of fuel will be drawn into the engine to produce a rich mixture for starting. When the throttle is fully opened, both inner and outer nozzles supply gasoline to the mixture. The spray nozzle construction is patterned largely after the Zenith, previously described. The carburetor shown at Fig. 170i is an English design, known as the " Scott-Robinson," and is a variable jet type -in which the air velocity and the flow velocity of the gasoline are automatically main- tained at a constant speed. This is accomplished by a dash pot arrangement in which a piston carrying a needle valve is mounted. Throttle Barrel Float Controlled, Needle Spray Nozzle Fig. 170i. Section of the Scott-Robinson Carburetor: an English Design. 352 The Modern Gasoline Automobile As the suction increases, the piston rises and more gasoline is sprayed into the mixture at the same time as more air is admitted through the main air inlet around the spray nozzle because of the increase in area of the air passage by the rising of the piston in the dash pot. As the amount of suction depends upon the throttle opening, and as the dash-pot piston will be drawn up higher as the suction becomes greater, more air and gasoline in a definite fixed ratio will be admitted to the mixing chamber. The normal position of the piston is down to a point approximately as shown in the illustration. The tapering needle valve has partly constricted the spray nozzle and the sides of the piston practically close the main air opening. The Diesel System. A system of fuel supply developed by the late Dr. Diesel, a German chemist and engineer, is attracting con- siderable attention at the present time on account of the ability of the Diesel engine to burn low-grade fuels, such as crude petroleum. In this system the engines are built so that very high compressions are used, and only pure air is taken into the cylinder on the induc- tion stroke. This is compressed to a pressure of about 500 pounds per square inch, and sufficient heat is produced by this compression to explode a hydrocarbon mixture. As the air which is compressed to this high point cannot burn, the fuel is introduced into the cylinder combustion chamber under still higher compression than that of the compressed air, and as it is injected in a fine stream, it is immediately vaporized because of the heat. Just as soon as the compressed air be- comes thoroughly saturated with the liquid fuel, it will explode on ac- count of the degree of heat present in the combustion chamber. Such motors have been used in marine and stationary applications, but have not yet been adapted to automobiles because of lack of flexibility and great weight in proportion to power developed. CHAPTER VI Automobile Power Plant Ignition Systems Outlined Chemical Current Pro- ducers Mechanical Generators of Electricity Essentials of Battery Igni- tion Systems Functions of Timers and Distributors Operating Prin- ciples of Induction Coil Spark Plug Construction and Action Defined Advantages of Two- Spark Ignition Typical Battery Ignition Groups Low-tension Ignition Systems High-tension Magneto Forms Typical Double Ignition Systems. ONE of the most important auxiliary groups of the gasoline engine comprising the automobile power plant and one absolutely necessary to insure engine action is the ignition system or the method employed of kindling the compressed gas in the cylinder to produce an explosion and useful power. The ignition system has been fully as well devel- oped as other parts of the automobile, and at the present time prac- tically all ignition systems follow principles which have become stand- ard through wide acceptance. During the early stages of development of the automobile various methods of exploding the charge of combustible gas in the cylinder were employed. On some of the earliest engines a flame burned close to the cylinder head and at the proper time for ignition, a slide or valve moved to provide an opening which permitted the flame to ignite the gas back of the piston. This system was practical only on the primitive form of gas engines in which the charge was not com- pressed before ignition. Later, when it was found desirable to com- press the gas a certain degree before exploding it, an incandescent platinum tube in the combustion chamber, which was kept in a heated condition by a flame burning in it, exploded the gas. The naked flame was not suitable in this application because when the slide was opened to provide communication between the flame and the gas the compressed charge escaped from the cylinder with enough pressure to blow out the flame at times and thus cause irregular ignition. When the flame was housed in a platinum tube it was protected from 353 354 The Modern Gasoline Automobile the direct action of the gas, and as long as the tube was maintained at the proper point of incandescence regular ignition was obtained. Some engineers utilized the property of gases firing themselves if compressed to a sufficient degree, while others depended upon the heat stored in the cylinder head to fire the highly compressed gas. None of these methods were practical in their application to motor car engines because they did not permit flexible engine action which is so desirable. At the present time, electrical ignition systems in which the compressed gas is exploded by the heating value of the mi- nute electric arc or spark in the cylinder are standard, and the general practice seems to be toward the use of mechanical producers of elec- tricity rather than chemical batteries. Two general forms of electrical ignition systems may be used, the most popular being that in which a current of electricity under high tension is made to leap a gap or air space between the points of the sparking plug screwed into the cylinder. The other form, which has been almost entirely abandoned in automobile practice, but which is still used to some extent on marine engines, is called the low- tension system because current of low voltage is used and the spark is produced by moving electrodes in the combustion chamber. The essential elements of any electrical ignition system, either high or low tension, are : First, a simple and practical method of current production; second, suitable timing apparatus to cause the spark to occur at the right point in the cycle of engine action ; third, suitable wiring and other apparatus to convey the current produced by the generator to the sparking member in the cylinder. The various appliances necessary to secure prompt ignition of the compressed gases should be described in some detail because of the importance of the ignition system. It is patent that the scope of a work of this character does not permit one to go fully into the theory and principles of operation of all appliances which may be used in connection with gasoline motor ignition, but at the same time it is important that the elementary principles be considered to some extent in order that the reader should have a proper understanding of the very essential ignition apparatus. The first point considered will be the common methods of generating the electricity, then the appliances to utilize it and produce the required spark in the cylinder. The M title nt (rr< l>e employed as a source of electricity for regular ignition service. Such devices are driven directly from the engine and the amount of energy they deliver is proportionate to the speed of rotation. When the engine is accelerated and more electricity is needed, the mechanical generator speed increases directly as that of the driving source, and more current is delivered as the demands upon the gener- ator augment. Dynamo Electric Machines. Two distinct types of mechanical . Coils Fig. 175. Distinctive Form of Current Producer Used on Ford Cars is Incor porated in the Power Plant Fly Wheel. ject being to absorb any heat which may be produced while the dynamo is in action. An appliance of this nature may be driven from the engine by belt, chain, or gear connection. It will deliver low voltage current which must be transformed by means of an induc- tion coil to current of higher value in order that it may be success- The Modern Gasoline Automobile 367 fully utilized to produce the spark in the combustion chambers of the engine. A \i-iy ingenious application of the dynamo is shown at Fig. 175. The elect rie generator is built in such a manner that it forms an integral part of the power plant. The magneto field is produced by a scries of revolving magnets which are joined to and turn with the fly wheel of the motor. The armature coils are carried by a fixed plate which is attached to the engine base. This apparatus is really a magneto having a revolving field and a fixed armature, and as the magnets are driven from the fly wheel there is no driving connection to get out of order and cause trouble. As the coils in which the cairrent is generated are stationary, no commutator or brushes are needed to collect the current because the electricity may be easily taken from the fixed coils by direct connection. It has been ad- vanced that this form of magneto is not as efficient as the conventional patterns Urause more metal and wire are needed to produce the cur- rent required. As the magnets which form the heavier portion of the apparatus are joined to the fly wheel, which can be correspondingly lighter, this disadvantage is not one that can be considered seriously Ill-cause the magnet weight is added to that of the motor fly wheel, the combined weight of the two being that of an ordinary balance member used on any other engine of equal power. Timer and Distributor Forms. Anyone familiar with the basic principles of internal combustion engine action will recognize the need of incorporating some device in the ignition system, which will insure that the igniting spark will occur only in the cylinder that is ready to be fired and at the right time in the cycle of opera- lion-. There is a certain definite point at which the spark must take place, this having been determined to be at the end of the compres- sion upstroke, at which time the gas has been properly compacted and the piston is about to start returning to the bottom of the cyl- inder again. Timers or distributors are a form of switch designed so that hundreds of positive contacts which are necessary to close and open the circuit may be made per minute without failure. \Yhen the device is employed to open and close a low-tension cir- cuit, it i< known as a commutator or timer, and when used in connec- tion with current of high voltage they are called secondary distribu- 368 The Modern Gasoline Automobile tors. Certain constructional details make one form different from the other, and while they perform the same functions they vary in design. Such distributing devices are always driven by positive gear- ing from the engine and are timed so the sparks will occur in the cylinders at just the proper ignition time. The usual construction is to use a fixed case which carries one or more contact members suitably disposed around its periphery and a central revolving member or cam which contacts with the points on the body of the device to close any desired circuit. On a four-cycle engine the cam is revolved at one half the engine speed and the timer is usually driven from the cam shaft. In two-cycle engines the revolving member of the timer turns at engine speed, and should be driven directly from and at the same speed as the crank shaft. Simple timer forms suitable for one-cylinder motors are shown at Fig. 175. The simplest one, depicted at A, consists of a rocking member of fiber or other insulating material which carries a steel spring that is normally out of engagement with the surface of the cam. When the point of the cam brushes by the contact spring, any circuit in which the device is incorporated will be closed and current will flow from the battery or dynamo to the transformer coils and spark plugs which are depended on to furnish a spark of sufficient intensity to insure ignition of the gas. It is desirable that the mem- ber which carries the contact spring be capable of a certain degree of movement, in order that the spark time may be advanced or retarded to suit various running conditions. In the form shown if the top of the casing is pushed in the direction of the arrow, the contact spring will come in contact with the point of the cam which is turn- ing in the direction indicated sooner than it will if the base member is rocked in a reverse direction and the contact spring pulled away from the point of the cam instead of being moved forward to meet it. The wipe contact form is the simplest, but the spring is liable to wear at the point of contact and may break off and cause trouble. Such a device is more suitable for low-speed engines than it is for those which have high crank-shaft velocity. The single-cylinder timer depicted at B is a form that is widely used on high-speed engines and contact is made between a pair of platinum contact points which just touch each other instead of wip- The Modern Gasoline Automobile 369 ing. Platinum is a material that is not affected by the arcing or heat of the spark as much as steel or brass would be and provides a more positive contact In the wipe contact form the continual brushing action of the cam against the spring tends to keep the contact surfaces clean, but this condition does not obtain in the simple touch contact of the form shown at B. The casing is rocked in the direction of Contact Points Fig. 176. Simple Forms of Contact Breakers Used on One-Cylinder Engines. A Wipe Contact. B Touch Contact. the arrow to advance a spark in either case. The form shown at B is more economical of current because the contact is shorter and is more suitable for high-speed engines. While the forms considered prove jmu-tical in their application to simple one- and two-cylinder engine 1 forms, they are very heavy or clumsy appliances when used for four- cylinder engines, as it is very hard to assemble the spring element so that the contact will take place at the proper point in all cylinders. When a timer is to be used in connection with a four- or six-cylin- der engine the compact form shown at Fig. 177, A, is usually adopted. This has many desirable features and permits of timing the spark with great accuracy. The contact segments are spaced on quarters and are imbedded in a ring of fiber which is retained in a casing of 370 The Modern Gasoline Automobile aluminum. The central revolving element carries a lever which has a roll at one end and a tension spring designed to keep the roller in contact with the inner periphery of the fiber ring at the other. The segments are of steel and are accurately machined and hardened, Fig. 177. Timers Employed on Four-Cylinder Engines. A Four-Contact Device for Commutating Primary Current. B Combined Timer and Dis- tributor Directs Both High- and Low-Tension Energy. and as the surface of the roller is also hardened, this form of timer is widely used because it provides a positive contact and works smoothly at all engine speeds. A secondary distributor which is employed to distribute both high- and low-tension current is shown at Fig. 177, B. This consists of a primary timing arrangement in the lower portion, and a secondary current-distributing segment at the upper portion. The central re- volving member carries as many rolls as there are cylinders to be fired, these being spaced at the proper points in the circle to insure correct timing. One primary contact member is screwed into the casing, this contacting with the rolls as they revolve. At the upper The Modern Gasoline Automobile 371 portion of the case a number of terminals are inserted from which wires lead to plugs in the cylinders. When a tinier of the form shown at Fig. 177, A, is used, a separate induction coil is needed for each cylinder and the number of units in the coil box and contact points on the timer will be the same as the number of cylinders to be fired. When a secondary distributor is employed but one induction coil is needed for all cylinders, because the secondary or high-tension current from one unit is distributed to the spark plugs at the proper time. Various wiring diagrams will be presented to show the methods of using timers and distributors. It will be noticed that the high-tension portion of the distributor is well insulated from the primary circuit closing member at the lower end. This is necessary because current of high voltage is much more difficult to handle than that of lower pressure, and it is more liable to short circuit. The arrangement of the contact points for various numbers of cylinders in roller contact timers is shown at Fig. 178. At A but Fig. 178. Showing Disposition of Contact Points on Timers for Number of Cylinders. A One-Cylinder Type. B Arrangement for Two-Cylinder Opposed Motor. C Contacts Separated by 90 Degrees in One Direction and 270 Degrees in the Other when Used on Two-Cylinder Vertical Engine with Opposed Crank Pins. D Three-Cylinder Form. E Suitable for Four-Cylinder Engines. F Type Employed on Six-Cylinder Power Plants. 372 The Modern Gasoline Automobile one segment is provided, this obviously serving only one cylinder. The form depicted at B is utilized with a double-cylinder opposed motor or a twin-cylinder vertical type in which both connecting rods act on a common crank pin or crank pins in the same plane. As the explosions are evenly spaced and the intervals separating the sparks are equal, the contact segments are placed diametrically opposite and are separated by a space of 180 degrees. If the two-cylinder engine is a vertical form having opposed cranks, the explosions will not be separated by equal intervals, so the segments must be placed to com- pensate for the difference which exists in the time interval separating the power impulses. Two contact segments are imbedded in the in- sulating ring, the contacts being separated by a space of 90 degrees on one side and 270 degrees on the other. This form of timer is seldom used at the present time because the two-cylinder engine of the pattern for which it is adapted has been practically discarded. When three cylinders are used the contact points are separated by a space of 120 degrees, as shown at D. In a four-cylinder timer the contact segments are spaced on quarters of the circle and are separated by a space equal to 90 degrees. With a six-cylinder motor six segments are necessary, these being separated by a space of 60 degrees, as shown at F. Before considering the other components of a battery ignition system it would be well to outline the essential elements of a simple ignition group so that the circuit and flow of current may be easily followed. Essential Elements of Simple Ignition System. The current ob- tained from the dry or storage battery or low-tension dynamo or magneto is not sufficiently powerful to leap the gap which exists be- tween the points of the spark plug in the cylinder unless it is trans- formed to a current having a higher potential. The air gap between the points of the spark plug has a resistance which requires several thousand volts pressure to overcome, and as a battery will only deliver six to eight volts, it will be evident that, unless the current value is increased, it could not produce a spark between the plug elec- trodes. The low voltage current is transformed to one of higher potential by means of a device known as the induction coil. The current from the battery is passed through the primary coil, which is composed of The Modern Gasoline Automobile 373 several layers of coarse wire wound around a core of soft iron to form an electro-magnet as shown at Fig. 179. Surrounding this primary coil is one composed of a large number of turns of finer Plug Ground Fig. 179. Simple Ignition System for One-Cylinder Motor Showing Important Components and Their Relation to Each Other. 374 The Modern Gasoline Automobile conductor. When a current of electricity of low voltage passes through the prima^ coil, a current of very high electro-motive force is produced in the secondary winding. One end of each coil is grounded. The free end of the primary coil is coupled to the battery while that of the secondary coil is attached to the insulated terminal of the spark plug. The arrangement of wiring at Fig. 179 is that employed in a typical transformer coil which is used to increase the voltage of the current sufficiently to cause it to overcome the resistance of the air gap at the spark plug and produce a spark which will ignite the gas. In the primary circuit are included a suitable timer for closing the circuit, a battery of chemical cells to supply the energizing ciirrent, and a vibrator or make-and-break mechanism on the coil. The sec- ondary circuit includes the spark plug and the secondary winding of the coil. When the primary circuit is closed by the cam of the timer making contact with the segment, the current from the battery flows through the primary coil of the transformer. This magnetizes the core which draws down the trembler blade, this in turn separating the platinum contact point of the vibrator and interrupting the current. As soon as the current is interrupted at the vibrator the core ceases to be a magnet and the trembler blade flies back and once again closes the circuit between the platinum points. Every time the circuit is made and broken at the vibrator an electrical impulse is induced in the secondary winding of the coil. The vibrator may be adjusted so that it will make and break the circuit many times a minute and as a current of high potential is produced in the secondary winding with each impulse, a small spark will be produced between the points of the spark plug. The condenser is a device composed of layers of tin foil separated from each other by waxed or varnished paper insulation. It is utilized to absorb some of the excess current produced between the vibrator points, which causes sparking. This extra current is induced by the action of the primary coils of wire upon each other and by a reversed induction in- fluence from the secondary coil. If this current is not taken care of, it will impede the passage of the primary current and the sparks are apt to burn or pit the The Modern Gasoline Automobile 375 platinum contact points of the vibrator. When a condenser is pro- vided the extra primary current is absorbed by the sheets of tin foil which become charged with electricity. When contact is made again the condenser discharges the current in the same direction as that (lowing through the primary coil from the battery and the value of the latter is increased proportionately. There is less sparking be- tween the vibrator points and a stronger current is induced in the secondary coil which in turn produces a more intense spark between the points of the spark plug. A typical induction coil such as would be used for firing a one- evlinder engine if used with a simple timer, or a multiple-cylinder Spring Adjustment Fig. 180. Part Sectional View of Simple Induction Coil, an Important Component of All Battery Ignition Groups and Sometimes Used with Magnetos. engine if used in connection with a combined timer and distributor,, is depicted in part section at Fig. 180. It will be observed that three terminal screws are provided on the box, one designed to be attached to the battery, the other two to the spark plug and ground, respec- tively. The terminal to which the battery wire is attached is coupled 'o the bridge member which carries the contact screw while the \i- 376 The Modern Gasoline Automobile brator blade is connected with one of the ends of the primary coiOL The other end of the primary coil goes to the terminal which i jo>ined' to the ground. The condenser is shunted in between the vibrator points, i. e., one of the leads is attached to terminal No. 1 while the other is soldered to the end of the primary coil which goes on the vibrator spring member. One end of the secondary coil is attached to terminal No. 2, which is grounded on some metal part of the chassis frame, while the other end is secured to terminal No. 3, which is joined to the spark plug electrode. After the various components of the induction coil are assembled in the box and the connections made as indicated, the spaces between the sides of the box and the coil member are filled with an insulating compound composed of bees- wax, pitch and rosin. This holds everything rigidly in place and prevents the wire joints loosening through vibration. The method of connecting the members of an induction coil, shown at Fig. 180, is a conventional one, though the connections will differ with the nature of the circuit of which the coil forms a part and the number of units comprising the coil assembly. When such devices are employed for igniting multiple-cylinder motors, the internal wiring is very much the same as though the same number of box coils for single-cylinder ignition were combined together by outside conductors. The number of terminals provided will vary with the number of units. Various forms of induction coils are depicted at Fig. 181. That at A is a simple unit form in which the coil is attached directly to the spark plug, which in turn is screwed into the cylinder. On this coil but two primary terminals are attached, one being connected to the insulated contact point on the timer, the other being grounded, or attached to the battery. Coils of this type have been very popular in marine application because of the simple and direct wiring possible, but they have not been used in connection with automobile engine ignition to any extent. The form shown at B is a simple dasli coil for one-cylinder use which has three terminals, one being used for a secondary lead to the spark plug, the other two being joined to the battery and ground respectively, as shown at Fig. 180. The form of coil shown at C is a two-unit member designed for double-cylinder ignition. As the switch is mounted on the coil box The Modern Gasoline Automobile 377 o use two sets of batteries, six terminals are provided on the bottom f the coil case. Two of these are attached directly to the insulated Fig. 181. Conventional Induction Coil Forms. A Coil Unit and Plug Com- bined. B Simple Box Coil for One-Cylinder Ignition. C Two-Unit Coil for Two-Cylinder Motors. D Four-Unit Coil for Four-Cylinder Service. 378 The Modern Gasoline Automobile contact point of the timer; two others which are enclosed in hard rubber insulating caps are attached to the spark plugs. The two imme- diately under the switch are attached to the free terminals of the bat- tery, two sets being provided, one being coupled to each side of' the switch. With a four-unit coil, as shown at D, ten terminals are provided because of the attached switch. Four go to the spark plugs, four to the insulated segments of the timer and two to the battery, or battery and magneto or dynamo, as the case may be. In modern coils the units may be removed from the box without disturbing any internal connection, and a new one slipped in its place if it does not function properly. Special care is taken in insulating the high-tension ter- minal by means of rubber caps which surround the wire, and care is taken to have the vibrator contact points readily accessible for in- spection, cleaning, or adjustment. Spark Plug Design and Application. With the high-tension system of ignition the spark is produced by a current of high voltage jump- ing between two points which break the complete circuit, which would exist otherwise in the secondary coil and its external connections. The spark plug is a simple device which consists of two terminal electrodes carried in a suitable shell member, which is screwed into the cylinder. Typical spark plugs are shown in section at Fig. 182 and the construction can be easily understood. The secondary wire from the coil is attached to a terminal at the top of a central electrode member, which is supported in a bushing of some form of insulating material. The type shown at A employs a molded porcelain as an insulator, while that depicted at B uses a bushing of mica. The in- sulating bushing and electrode are housed in a steel body, which is provided with a screw thread at the bottom, by which it is screwed into the combustion chamber. When porcelain is used as an insulating material it is kept from direct contact with the metal portion by some form of yielding pack- ing, usually asbestos. This is necessary because the steel and porce- lain have different coefficients of expansion and some flexibility must be provided at the joints to permit the materials to expand differently when heated. The steel body of the plug which is screwed into the cylinder is in metallic contact with it and carries sparking points The Modern Gasoline Automobile 379 which form one of the terminals of the air gap over which the spark occurs. The current entering at the top of the plug cannot reach I the ground, which is represented by the metal portion of the engine, until it has traversed the full length of the central electrode and overcome the resistance of the gap between it and the terminal point on the shell. The porcelain bushing is firmly seated against the Spring Washer Fibre Washer LJ Long . -|l Porcelain Sleeue > I Heavy Nickel Points flBM Standard I M Thread Hp So//rf /WcAe/ Hod. Mica Insulation Fig. 182. Spark Plug Construction OutKned. A Sectional View of Porcelain Plug. B Part Sectional View of Mica Plug. asbestos packing by means of a brass screw gland which sets against a flange formed on the porcelain, and which screws into a thread at the upper portion of the plug body. The mica plug shown at B is somewhat simpler in construction than that shown at A. The mica core which keeps the central elec- trode separated from the steel body is composed of several layers of pure sheet mica wound around the steel rod longitudinally, and hun- dreds of stamped steel washers which are forced over this member 380 The Modern Gasoline Automobile and compacted under high pressure with some form of a binding material between them. Porcelain insulators are usually molded from high grade clay and are approximately of the shapes desired by the designers of the plug. The central electrode may be held in Sparh Points Sparh Points Fig. 183. Three Forms of Spark Plugs in which Electrodes are Separated by Porcelain Insulation. place by mechanical means such as nuts, packings, and a shoulder on the rod., as shown at A. Another method sometimes used is to cement the electrode in place by means of some form of fire-clay cement. Whatever method of fastening is used, it is imperative that the joints be absolutely tight so that no gas can escape at the time of explosion. With a mica plug the electrode and the insulating bushing are really a unit construction and are assembled in permanent assembly at the time the plug is made. Other insulating materials sometimes used are glass, steatite (which is a form of soapstone), and lava. Mica and porcelain are The Modern Gasoline Automobile 381 the two common materials used because they give the best results. Glass is liable to crack while lava or the soapstone insulating bushings absorb oil. The spark gap of the average plug is equal to about ^ of an inch for coil ignition and from ^ to -^ of an inch when used in magneto circuits. A simple gauge for determining the gap setting is the thickness of an ordinary visiting card for magneto plugs, or a space equal to the thickness of a worn dime for a coil plug. The insulating bushings are made in a number of different ways, and while details of construction vary, spark plugs do not differ essen- tially in design. Three different forms of plugs using porcelain insu- lation are shown in part section at Fig. 183. Porcelain is the ma- terial most widely used because it can be glazed so that it will not absorb oil, and it is subjected to such high temperature in baking that it is not liable to crack when heated. The spark plugs may be screwed into any convenient part of the combustion chamber, the general practice being to install them in the , Spark Plug Electrodus Pocket Fig. 184. Methods of Installing Spark Plugs of Conventional Form. A In- correct Method. B Correct Installation in Valve Chamber Cap. C Combined with Cylinder Priming Device or Compression Relief Cock. caps over the inlet valves, or in the side of the combustion chamber, so the points will be directly in the path of the entering fresh gases from the carburetor. The methods of spark plug installation com- monly used are shown at Fig. 184. At A the plug is screwed into a threaded hole which passes through the valve cap in such a manner 382 The Modern Gasoline Automobile that the points are in a pocket. This is not considered to be as good as the method depicted at B, where the interior of the valve cap is recessed out so there is considerable space around the spark point. When the electrodes are carried in a pocket they are more liable to become short circuited by oil or carbon accumulations, because it is difficult for the fresh gases to reach them and the pocket tends to retain heat. Ignition is not so certain because some of the burned gases may be retained in the pocket and prevent the fresh gas from getting in around the spark gap. With a recess, as shown at B, condi- tions are more favorable because the fresh gases can sweep the points of the spark plug and keep them clear, and also because of the larger space any burned products retained in the cylinder are not so apt to collect around the plug point. On some types of engines which are not provided with compression relief, or priming cocks, plugs are sometimes installed, as shown at C. A special fitting, which carries a priming cup at one side, is screwed into the cylinder and the spark plug is fitted to its upper portion. When it is desired to relieve the compression, the valve portion is turned in such a way that a passage is provided from the interior of the fitting to the outer air. At the same time when the valve is in the position shown in illustration, gasoline may be introduced into the cylinder for priming purposes. It is advanced that this method of constructon also provides a simple means of freeing the plug points from oil or particles of carbon if the cock is opened while the engine is running. The high pressure gas which brushes by the points on its way out of the cylinder tends to dislodge any particle of foreign matter which may be present near the spark gap. The same objections apply to this method of mounting as to that illustrated at A. Spark plugs are made in many different forms and some have been designed with a view of permitting one to see if the charge is being exploded regularly in the cylinder by some form of transparent material for insulation, so that the light produced by the explosion could be seen from the outside of the cylinder. The simplest method of determining if a spark is occurring regularly between the points is to use some form of spark gap which is interposed between the source of current and the plug terminal. A device of this nature is The Modern Gasoline Automobile 383 shown at Fig. 185, A. It consists of a body of insulating material which carries in a glass tube two points, which are separated by a slight air space. The eye or hook end is attached to the plug ter- minal, while the other end is attached to the secondary wire. If the current is passing between the points of the plug, a spark will take Terminal for 'High Tension Wire Clip\ High Tension Cable ' Fig. 185. Novel Spark Plugs and Accessory Parts. A Spark Gap Designed to be Placed in Series with Plug Electrode and Current Source. B Plug Shell with Glass Insets to Show Spark. C Spark Plug with Waterproof Terminal Cover. place between the points of the auxiliary spark gap every time one occurs between the points of the plug in the cylinder. It is claimed that there are certain advantages obtained when a spark gap is used in the circuit, in that the spark in the cylinder is more effective and less liable to be short circuited by particles of foreign matter. At the other hand, others contend that the current must be stronger to jump two gaps than would be required if only 384 The Modern Gasoline Automobile the resistance of one was to be overcome. While very popular at one time, the spark gap is of rather doubtful utility and is seldom used at the present time, except as a means of indicating if spark has taken place between the points of the spark plug. It is apt to be somewhat misleading, however, because even if the points of the plug are short circuited and no spark is taking place between the plug points, and yet current is passing to the ground, a spark will con- tinue to take place at the auxiliary spark gap. The device is use- ful in showing when there is a break or derangement of the wiring or coils. A form of spark plug having glass bull eyes set into the plug shell or body is shown at Fig. 185, B. These simple lenses are made of specially compounded glass, which has a high resistance to heat and every time an explosion takes place in the cylinder the light resulting causes a flash which is readily seen through the lens. If the flashing is regular it is safe to assume that the cylinder is functioning prop- erly, but should the flashes be intermittent or separated by unequal intervals of time the cylinder is missing explosions. It is often desirable to have a water-tight joint between the high tension cable and the terminal screw on top of the insulating bush- ing of the spark plug, especially in marine applications. The plug shown at C is provided with an insulating member or hood of porce- lain, which is secured by a clip in such a manner that it makes a water-tight connection. Should the porcelain of a conventional form of plug become covered with water or dirty oil, the high-tension cur- rent is apt to run down this conducting material on the porcelain and reach the ground without having to complete its circuit by jumping the air gap and producing a spark. It will be evident that wherever a plug is exposed to the elements, which is often the case in motor- cycle or motor-boat service, that it should be protected by an insulat- ing hood which will keep the insulator dry and prevent short circuit- ing of the spark. Plugs for Two-Spark Ignition. On some forms of engines, es- pecially those having large cylinders, it is sometimes difficult to secure complete combustion by using a single-spark plug. If the combustion is not rapid the efficiency of the engine will be reduced proportionate- ly. The compressed charge in the cylinder does not ignite all at The Modern Gasoline Automobile 385 once or instantaneously, as many assume, but it is the strata of gas nearest the plug which is ignited first. This in turn sets fire to con- secutive layers of the charge until the entire mass is aflame. One may compare the combustion of gas in the gas-engine cylinder to the phenomena which obtains when a heavy object is thrown into a pool of still water. First a small circle is seen at the point where the object has passed into the water, this circle in turn inducing other and larger circles until the whole surface of the pool has been agitated from the one central point. The method of igniting the gas is very similar as the spark ignites the circle of gas immediately adjacent to the sparking point, and this circle in turn ignites a little larger one concentric with it. The second circle of flame sets ; fire to more of the gas, and finally the entire contents of the combus- tion chamber are burning. While ordinarily combustion is sufficiently rapid with a single plug so that the proper explosion is obtained at moderate engine speeds, if the engine is working fast and the cylinders are of large capacity, ' more power may be obtained by setting fire to the mixture at two different points instead of but one. This may be accomplished by using two sparking plugs in the cylinder instead of one, and experi- ments have shown that it is possible to gain from twenty-five to thirty per cent in motor power at high speed with two-spark plugs, because the combustion of the gas is accelerated by igniting the gas simul- taneously in two places. To fit a double-spark system successfully, one of the plugs must be a double pole member to which the high- tension current is first delivered, while the other may be one of ordinary construction. A typical double-pole plug is shown in section at Fig. 186, A. In this member two concentric electrodes are used, these being well in- sulated from each other. One of these is composed of the usual form passing through the center of the insulating bushing, while the other is a metal tube surrounding the tube of insulating material which is wound around the center wire. The current enters the plug through the terminal at the top in the usual manner, but it does not go to the ground because the sparking points are insulated from the steel body of the plug which screws into the cylinder. After the current has jumped the gap between the sparking head and the point, it 386 The Modern Gasoline Automobile flows back to the terminal plate at the top, from which it is conducted to the insulated terminal of the usual type plug. The method of wiring these plugs is shown at Fig. 186, B. The secondary wire from the coil or magneto is attached to the central Mica Washers Fig. 186. Double-Pole Spark Plug and Method of Applying It to Obtain Two Sparks in the Cylinder. terminal of the double-pole plug, and another cable is attached to the insulated terminal plate below it and to the terminal of the regu- lar type plug. One is installed over the inlet valve, the other over the exhaust valve, if the system is fitted to a T head cylinder. Before the current can return to the source it must jump the gap between the points of the double-pole plug as well as those of the ordinary plug, which is grounded because it is screwed into the cylinder. When a magneto of the high-tension type furnishes the current a The Modern Gasoline Automobile 387 double distributor is sometimes fitted, which will permit one to use two ordinary single-pole plugs instead of the unconventional double- pole member. Each of the plugs is joined to an individual distrib- utor, and as but one primary contact breaker or timer is used to determine the time of sparking at both plugs, the ignition is properly synchronized and the sparks occur simultaneously. Typical Battery Ignition Systems. The components of typical bat- tery ignition systems may be easily determined by studying the illus- trations given at Figs. 187, 188, and 189. The four-cylinder ignition group shown at Fig. 187 depicts the conventional method of wiring High Tension Wires Induction Coil Switch Primary Circuit Dry Coils ^Storage Battery ?ig. 187. Assembly View of Four-Cylinder Ignition Group Showing All Devices and Methods of Wiring. two sets of batteries, a four-point timer or commutator, and a four- init induction coil together. It will be seen that eight dry cells are wired together in series and are used as an auxiliary to a six-volt or three-cell storage battery. The negative terminals of the storage bat- :ery and dry cell set are coupled together by a short length of wire 388 The Modern Gasoline Automobile and are grounded by being attached to the engine base by a suitable -conductor. The positive terminals are coupled to the two binding posts under the switch or the coil. The four points of the commutator are attached to the different units of the coil while the secondary wires run from the high-tension terminals on the bottom of the coil to the spark plugs in the cylinders. If the switch lever is placed on one contact button, the current is obtained from the dry cells. If it is swung over to the other side, electricity from the storage batterv is utilized. Fig. 188. Methods of Employing Single Coil to Fire Four Cylinders when Sec- ondary Current is Distributed Instead of Battery Energy. A typical high-tension distributor 'system is shown at Fig. 188. Two sources of primary current are provided, one being a six-cell, dry battery, the other a three-cell, or six-volt storage battery. The bat- tery connections are similar to those previously shown and but a single unit coil is needed to fire all cylinders. A single primary wire is attached to the commutator section of the distributor. The second- The Modern Gasoline Automobile 389 ary wire from the induction coil is joined to the distributing terminal on the top of the distributor, from which it is delivered to the collect- ing terminals spaced on quarters around the outer periphery of the distributor casing by means of a central distributing segment. Suit- able conductors connect the distributor with the spark plugs in the cylinders. Side View Firing Order 1,2,3,6,5,4- ^Ground ^Cylinde. Fig. 189. Distributor and Coil Ignition Group for Six-Cylinder Motor Showing Order of Firing and Wiring Connections Clearly. The illustration at Fig. 189 is practically the same as that at Fig. 188, except that a distributor capable of firing a six-cylinder engine is used. If individual unit coils were to be employed, as is the case at Fig. 187, the coil box would contain six units and the primary timer would have six contact points. The wiring would be considerably more complicated than the system outlined. Features of Low-Tension Ignition System. Though the low-tension i- n it ion system is seldom used at the present time, a brief descrip- tion of the method of producing a make-and-break spark is desirable so the reader may gain a thorough knowledge of the methods of ignition the vogue. In order to obtain a spark in the cylinder of any 390 The Modern Gasoline Automobile engine, it is necessary that there be a break in the circuit and that this break or interruption be inside of the combustion chamber. The igniter plate used is different in construction from the spark plug forming part of the high-tension system, as the break is made by moving contacts which serve to time the spark as well as produce it. Plate Fig. 190. Low-Tension Ignition Plate by which Spark is Produced in Some Locomobile Engine Cylinders. A External View Showing Rocker Arm. B Interior View Depicting Contact Points. C Method of Operation. A typical igniter is shown at A and B, Fig. 190. It consists of a drop-forged plate approximately triangular in form which has a coni- cal ground surface to fit a corresponding female member in the com- bustion chamber. It is secured by three bolts to a corner of the The Modern Gasoline Automobile 391 cylinder close to the inlet valve so the contact points will be traversed by the gases entering from the carburetor. As shown at B, the fixed contact point is called the anvil, while the movable or rocking mem- ber is called the hammer. The anvil is insulated from the igniter plate by a bushing of mica or lava, and the hammer alternately makes and breaks contact with the anvil. The method of actuating the ham- mer by a rocker arm is clearly shown at C. The rocker arm 5 is in the form of a short lever ending in a slotted opening which is con- nected to the top of the vertical lifter rod 9. This "is actuated by a cam on the inlet valve cam shaft which raises the valve plunger 11 in the guide bushing 10. When the lifter rod moves upward the con- tact point on the hammer inside of the cylinder comes into contact with the platinum point on the anvil and closes the circuit. When the igniter cam reaches the proper point for igniting the charge the lifter rod 9 falls and as the action is quickened by a spring at the bottom of the lifter rod the hammer arm 4 is separated from the con- tact point on the anvil 6 and a spark takes place as the points are lied apart. The coil used when batteries are employed to furnish the current a simple form. It is a winding of comparatively coarse wire around a core composed of a bundle of soft iron wire. The battery current is intensified to a certain extent by the self-induction of one layer of wire upon the others, and when contact is broken a brilliant spark occurs between the points of the igniter plate. Batteries are sel- dom used for regular service on the low-tension system because the demands are too severe. One of the advantages of this system is that the wiring is ex- tremely pimple, as will be seen by consulting the diagram of the low- tension ignition system illustrated at Fig. 191. In this both a low- tension magneto and set of batteries are provided, the former being iist-i! for regular ignition while the latter are carried for emergency service. A simple form of magneto will serve any number of cyl- inders because the insulated terminals of the igniters are joined to- gether by a simple conductor or bus bar. A wire from the magneto terminal is joined to one side of the switch, while the other side of the switch is coupled to the coil which is carried in the battery box. A short wire connects the top of the switch lever with the bus bar. 392 The Modern Gasoline Automobile If the switch lever is swung to the left, the magneto produces the current for the igniters, and if the switch lever is placed on the button at the right, the current supply is taken from the batteries. The dry Battery Magneto Battery Fig. 191. Low-Tension Ignition System for Four-Cylinder Motor Utilizes Bat- tery and Magneto for Current Production. Note Simple Wiring All Con- ductors Conveying Low-Tension Current. cells are joined together in series connection, one pole being joined to a coil terminal, the other being grounded. The coil and the igniter plates are in series with the batteries and the current is returned to the ground through the rocker arm, which is a metallic contact with the igniter plate. The disadvantage which has militated, against the general use of the make-and-break system, of ignition is that it is very difficult to obtain synchronized spark after the mechanism had become worn, and unless the igniter plates were kept in perfect adjustment the spark time would vary and the efficiency of the engine would be lowered. As the moving electrodes operate under extremely disadvantageous conditions it is difficult to prevent rapid wear of the rocker arm bearing at the igniter plate and consequent leakage of gas results. The Modern Gasoline Automobile 393 Owing to the multiplicity of joints in the operating mechanism it is difficult to secure regular action without hacklash or lost motion. With a high-tension system there are no moving parts inside of the cylinder and it is not difficult to maintain a tight joint between the plug body and the cylinder head. The timer mechanism which is employed when batteries and coils are utilized to furnish the cur- rent is a comparatively simple device which is not liable to wear be- cause it can be easily oiled and has a regular rotating movement which can operate without getting out of time much better than the recipro- cating parts of the make-and-break mechanism. When a direct high- tension magneto is used the system is not much more complicated as far as wiring is concerned than a low-tension group, and as the ignition is more reliable it is not strange that jump spark or high- tension ignition is almost generally used in automobile practice. Carbon Ring Brass ^Condenser Timing Case Fig. 192. Simple High-Tension Magneto for One-Cylinder Ignition. A Com- plete Apparatus Comprising Source of Current and Timing Device as Well. Magneto Generator Construction. The magneto is a simple form of dynamo and a mechanical generator of electricity in which per- manent magnets are used to produce the magnetic field and between which the armature revolves. The permanent magnets are called " field magnets " and at their ends are provided cast-iron shoes which 394 The Modern Gasoline Automobile form the walls of the armature tunnel and which are known as pole pieces. A typical magneto adapted for single-cylinder ignition is shown in section at Fig. 192. It consists of two compound horse- shoe magnets attached to the pole pieces which collect and concentrate the magnetism upon the armature. The armature is shuttle-shaped and carries a double winding of wire which consists of two coils, one of coarse, the other of fine conductor. The armature is attached to end pieces which carry shafts and the whole assembly revolves on annular ball bearings. An ebonite or hard rubber spool is carried at one end while the condenser is housed at the other. The make- and-break mechanism is partly carried by an oscillating casing and the revolving member is turned from the armature shaft. The current generated in the coil is delivered to a metal ring on the ebonite spool from which it is taken by a carbon brush and de- livered directly to the spark plug. Every time the contact points in the make-and-break devices become separated, a current .of high potential passes through the wire attached to the spark plug and produces a spark between the points. The magneto is the simplest and most practical form of ignition appliance as it is self-contained and includes the current generator and the timing device in one unit. In the one-cylinder form shown all connections are made inside of the device and but one wire leading to the spark plug is necessary to form the external circuit. A magneto employed for multiple-cylinder ignition is not much more complicated than that used for single-cylinder service, the only difference being that a different form of cam is provided in the breaker box and that a secondary distributor is added to commutate the current to the plugs in the various cylinders. The distributor consists of a block of insulating material fixed to the magnets which carries as many segments as there are cylinders to be fired. A cen- tral distributing arm or segment is driven from the armature shaft by means of gearing, and is employed to distribute the high-tension current to the spark plugs. The spacing of the distributor segments does not differ materially from that of the battery timers previously described. Various distributor forms used on magnetos are shown at Fig. 193. That at A is employed for a double opposed cylinder motor and The Modern Gasoline Automobile 395 the contacts are separated by a space of 180 degrees. When a three- cylinder engine is used, as is sometimes the case in the two-cycle forms, the distributor segments are separated by distances of 120 degrees. Fig. 193. How Distributor Contacts are Spaced on Two-, Three-, Four- and Six- Cylinder Magnetos. If the distributor is used on a four-cylinder motor the segments are spaced 90 degrees apart, as shown at C. To fire a six-cylinder motor, six segments must be used and they are placed 60 degrees apart, as indicated at D. The speed at which the armature of the magneto turns also varies with the number of cylinders. One- and two-cylinder forms turn at cam-shaft speed. The three-cylinder types when applied to a four- cycle engine turn at three quarters the crank-shaft speed. The four- 396 The Modem Gasoline Automobile cylinder magneto armature is driven at crank-shaft speed, while that of the six-cylinder forms turn at one and one half times crank-shaft speed. When used on two-cycle motors, the speeds given for four- cycle engines of the same number of cylinders should be doubled. The important parts of a four-cylinder form of high-tension mag- neto are shown at Fig. 194, which is a view of a partially dismantled device. The armature assembly and one of the end plates by which it is supported are shown at the extreme left. Attached to the end of the armature shaft are the distributor drive pinion and the ebonite spool which carries the collector ring. The timer case and interrupter assembly are shown at the extreme right. Above it the distributor case is clearly depicted. When the device is assembled the end of the armature shaft protrudes through the housing at the lower part of the magnet assembly which is shown in the center of the group, with the end plate which carries the distributor gear and disk and one end of the armature in place. The distributor gear serves to drive a hard rubber plate in which the distributor segment is imbedded. When the distributor case is screwed in place, the carbon brushes, which are spaced around the interior of the distributor case, collect current from the revolving distributor segment and lead it to the spark plugs by suitable cables which run from the terminals at the top of the distributor casing. Two systems of high-tension magneto ignition are used, one termed the true high-tension system, in which a current of high po- tential is delivered directly from the armature ; the other is the trans- former coil system, so termed because the current produced by the armature winding is of low tension and must be stepped up or in- creased in value before it is delivered to the spark plug by an induc- tion coil similar in construction to that needed in battery-ignition systems. In the former apparatus the high-tension current is pro- duced by means of a secondary winding on the armature itself, and as the whole apparatus is self-contained it is much more compact and simpler to install than those which need a separate transformer coil. The simplified wiring system of a true high-tension magneto is shown at Fig. 195. The armature carries two windings, one indicated by the heavier lines at the bottom called the " primary " ; the other, composed of finer conductor, is known as the " secondary." One end < -nine sensibly greater in weight. As the water becomes cooler, it falls to the bottom of the radiator and it is again supplied to the 440 The Modern Gasoline Automobile water jacket. The circulation is entirely automatic and continues as long as there is a difference in temperature between the liquid in the water spaces of the engine and that in the cooler. The circula- tion becomes brisker as the engine becomes hotter and thus the tem- perature of the cylinders is kept more nearly to a fixed point. With the thermosyphon system the cooling liquid is nearly always at its boiling point, whereas if the circulation is maintained by a pump the engine will become cooler at high speed and will heat up more at low speed. There are two methods of applying the thermosyphon system in a practical manner, the most common being that outlined at Fig. 223. Here the radiator is carried at the front end of the car and a fan Tight Motor Compartment Underpan Flywheel Fan Fig. 224. Renault Thermosyphon System, in which Radiator is Placed in Back of Engine Instead of in Front, as is Conventional Practice. A Showing Method of Utilizing Fan Fly Wheel to Insure Air Circulation Through Radia- tor. B Plan View Depicting Flow of Air Currents Through Cooler. driven from the crank shaft by belt connection is used to draw the air through the radiator. The other system, which is illustrated at Fig. 224, is one that was introduced on the Eenault automobile In this the radiator is mounted just forward of the dashboard instead of at the front of the frame. The air draught through the radiator is produced by the suction effect of a fan member which is incorporated with the fly wheel. When a radiator is mounted at the front end of a frame, it is one of the most vulnerable portions of the motor-car mechanism, and as The Modern Gasoline Automobile 441 they are delicately constructed they may be easily damaged in collis- ion. When installed as shown at Fig. 224, they are protected by the heavier construction of the cylinders and other portions of the motor and are not liable to be damaged. Then again, as the fan is incorpo- rated with the fly wheel and driven directly by the crank shaft of the motor, there is no possibility of failure of this member, such as might be possible when it is driven by a belt connection from the front end of the engine. With the therm osyphon or natural system of cooling more water must be carried than with the pump maintained circulation methods. Water Outlet Water Inletr"" Fig. 226. Showing Large Water Manifolds Designed to Secure Positive Circu- lation by Thermosyphon or Natural Methods. The water spaces around the cylinders should be larger, the inlet and discharge water manifolds should have greater capacity, and be free from sharp corners which might impede the flow. The radiator must also carry more water than the form used in connection with the pump because of the brisker pump circulation which maintains the 442 The Modern Gasoline Automobile -ran Blade. Grease Cup. engine temperature to a lower point. The large piping which expe- rience has shown necessary is clearly shown in views previously de- scribed and in Fig. 225. The form of fan which is gen- erally placed behind the radiator with either system of water cool- ing and which is often used in the simple air-cooling systems as well, is shown in part section at Pig. 226. The hub is usually a cast- aluminum member which has a series of projecting spokes to which the fan blades are riveted. The blades are inclined at the proper angle to draw air through the radiator and force it to the rear of the motor compartment. As a fan requires but little power, they are usually driven by small leather belts and as they operate at speeds two or three hundred per cent greater than that of the motor- crank shaft they are mounted on ball bearings in order that they may turn with as little friction as possible. The fan spindle is usually supported by some form of movable bracket which can be ad- justed so that the fan belt may be maintained at a constant degree of tension. Direct Air-Cooling Methods. The earliest known method of cool- ing the cylinder of gas engines was by means of a current of air passed through a jacket which confined it close to the cylinder walls and was used by Daimler on his first gas engine. The gasoline engine Fig. 226. Typical Bail-Bearing, Hub- Cooling Fan Designed to Create Air Draught Through Radiator and Around Cylinders of Motor-Car Power Plant. The Modern Gasoline Automobile 443 of that time was not as efficient as the later form, and other condi- tions which materialized made it desirable to cool the engine by water. Kvi'ii as gasoline engines became more and more perfected there has al \vays existed a prejudice against air cooling, though many forms of engines have been used, both in stationary and automobile applications where the air-cooling method has proven to be very practical. The simplest system of air cooling is that in which the. cylinders are provided with a series of flanges which increase the effective radi- ating surface of the cylinder and directing an air current from a fan against the flanges to absorb the heat. This increase in the avail- ,Cooling Fan Flanged Cylinders Fig. 227. Air-Cooling System Employed on Cameron Motors Depends Upon Air Draught from Fan to Circulate Around Flanges on Cylinders and Absorb Excess Heat. able radiating surface of an air-cooled cylinder is necessary because air does not absorb heat as readily as water and therefore more sur- face must be provided that the excess heat be absorbed sufficiently fast to prevent distortion of the cylinders. Air-cooling systems are based on a law formulated by Newton, which is : " The rate for cooling for 444 The Modern Gasoline Automobile a body in a uniform current of air is directly proportional to the speed of the air current and the amount of radiating surface exposed to the cooling effect." A simple four-cylinder power plant in which cooling is obtained by air blast against the flanges of the cylinders is depicted at Fig. 227, and views of a cylinder and detachable head construction also adapted to be cooled by air are shown at Fig. 228. Piston Rings K Connecting Rod Detachable Head Fig. 228. Parts of Air-Cooled Cylinder Showing Method of Seating Valves Directly in Detachable Cylinder Head, and Large Flanges on Both Cylinder and Head Member to Largely Increase Effective Radiating Surface. There are certain considerations which must be taken into ac- count in designing an air-cooled engine, which are often overlooked in those forms cooled by water. Large valves must be provided to insure rapid expulsion of the flaming exhaust gas and also to admit promptly the fresh cool mixture from the carburetor. The valves of air-cooled engines are usually placed in the cylinder head, as shown at Figs. 227 and 228, in order to eliminate any pockets or sharp pas- sages which would impede the flow of gas or retain some of the products of combustion and their heat. When high power is desired multiple-cylinder engines should be used, as there is a certain limit to the size of a successful air-cooled cylinder. Much better results are secured from those having small cubical contents because the heat from small quantities of gas will be more quickly carried off than from greater amounts. All successful engines of the automobile type which have been air cooled have been of the multiple-cylinder type and the use of single cylinders is confined to power plants of less than five horse power such as used in motorcycle construction. The Modern Gasoline Automobile 445 An air-cooled engine must be placed in a chassis in such a way that there will be a positive circulation of air around it all the time that it is in operation. This air current may be produced by a fan at the front end of the motor, by natural draught when a car is in motion, or by a suction or blower fan in the fly wheel. Greater i-;uv is required in lubrication of the air-cooled cylinders and only the best quality of oil should be used to insure satisfactory oiling. The combustion chambers must be proportioned so that distribu- tion of metal is as uniform as possible in order to" prevent uneven expansion during increase in temperature and uneven contraction when the cylinder is cooled. It is essential that the inside walls of the combustion chamber be as smooth as possible because any sharp , angle or projection may absorb sufficient heat to remain incandescent and cause trouble by igniting the mixture before the proper time. The best grades of cast iron should be used in the cylinder and piston and the machine work must be done very accurately so the piston will operate with minimum friction in the cylinder. Utility of Auxiliary Exhaust Valves. As an example of the care taken in disposing of the exhaust gases in order to obtain practical air cooling the illustration at Fig. 229 is presented. This is a sec- tion through the bottom of one of the Franklin power plants and shows the auxiliary exhaust valve which is furnished as an adjunct to the regular member in the cylinder head. The auxiliary exhaust valve opens just as soon as the full force of the explosion has been spent and the greater portion, or 70%, of the flaming gases is dis- charged through the port in the bottom of the cylinder. But 30% of the exhaust gases remain to be discharged through the regular exhaust member in the cylinder head and this will not heat the walls of the cylinder nearly as much as the larger quantity of hot gas would. That the auxiliary exhaust valve is of considerable value is conceded by many engineers unless exceptional care is taken in the method of cooling employed. The earlier Franklin engine, which used the auxil- iary exhaust valves, was cooled by an air blast from a fan at the front end which was directed against flanges applied to the cylinders, but on later models the auxiliary valve has been dispensed with be- <-ausp the more positive system of cooling provided makes its use unnecessary. 446 The Modern Gasoline Automobile One of the important considerations in connection with air cool- ing is that the air blast be confined as close to the cylinders as possible and a more energetic flow of air is needed than with water-cooling Cooling Flanges. Auxiliary Exhaust Valve. Fig. 229. Depicting Section Through Power Section of One Type of Franklin Engine, Showing Application of Auxiliary Exhaust Valve to Relieve Cylinder of Flaming Gases at End of Power Stroke. systems. The form of fan shown at Fig. 226 and at Fig. 230, A, is considered entirely adequate for water-cooled engines, but engineers who favor air cooling at the present time use blower forms such as The Modern Gasoline Automobile 447 shown at Fig. 230, B, which will furnish larger quantities of air than Ithe simple fan would and which also direct it to the cylinders in a positive manner by enclosing them in air jackets which are attached !to a manifold member to which the discharge opening of the blower is coupled. The discussion of air cooling so far has considered only the adapta- bility to the four-stroke motor and many believe that it is not possible Blower Blades. Crank-shaf Gear. Air Inlet Fig. 230. Two Forms of Positive Air Fans Used in Automobile-Cooling Systems. A Gear-Driven, Three-Blade Fan Utilized to Draw Air Through Winton Radiator. B Blower Member Used on Kelly Air-Jacketed Cylinder Motor. to cool two-cycle engines by this method because the great heat gen- erated in engines of this type is thought to make the use of water cooling imperative. As the two-cycle motor has an explosion in each cylinder, every revolution of the crank shaft, and has no strokes devoted exclusively to scavenging, it is true the cylinder walls will heat up more. Several forms of two-cycle engines have been evolved, however, in which positive cooling has been obtained by providing the cylinders with cooling ribs. One of these, which is used in the Chase light truck, is depicted in section at Fig. 231. It will be noted that 448 The Modern Gasoline Automobile the exhaust ports are large and that the transfer port for the passage of the gas from the crank case to the cylinder is proportioned so that it will have a minimum resistance to the gas flow. Two engines of modern devel- opment which utilize positive air- cooling methods are shown at Figs. 232 and 233. The system of cool- ing is practically the same in both instances, except in the methods employed of creating the air blast. In the Franklin system the cyl- inders are provided with vertical ribs, or flanges, and are encased by jackets which form part of a sheet-metal casing that covers the entire lower portion of the power plant. The fly wheel is provided with a series of curved llower blades and as it turns it creates a partial vacuum in the compartment formed by the mo- tor-base casing and the air-tight underpan. The strong suction created draws air in from the front end of the bonnet and down through the cylinder jackets. The air currents pass over the flanges at high velocity and as there is a large amount of exposed surface the excess heat is promptly dis- posed of and absorbed by the air passing around the cylinders which is ejected from the motor-base compartment by the action of the blower fly wheel. As the fan is part of the balance member and is driven direct from the engine crank shaft there can be no failure of the driving means and a positive air draught must be induced around the cylinders as soon as the motor is started. The velocity of the air currents increase directly as the motor speed augments, and positive cooling is obtained under all conditions. Fig. 231. Sectional View of Chase Two-Cycle Engine, a Two-Stroke Form Successfully Cooled by Air Flanges Cast Integral with Cylinder. The Modern Gasoline Automobile 449 In the Prayer-Miller engine which is used in the Kelly trucks, the mot hod of cooling is different in detail but practically the same in principle as that previously described. An air blower is mounted at the front end of the motor and the strong current of air it produces is conveyed to an air pipe at the top of the cylinders, to which the j;u -kfts surrounding them are attached. The cylinder heads are pro- vided with a series of vertical flanges, but the cylinder-wall area is Fig. 232. Positive Cooling Method Used on Franklin Automobiles in which Air Currents are Drawn Through Cylinder Jackets by Fly-wheel Fan Suction. increased by using a large number of spines which are cast integral with the cylinder. The air blower forces a blast of air into the air pipe above the cylinders at considerable pressure, and the only way it can escape is by passing around the heated portion of the cylinder before it is discharged through the bottom of the air jacket. As the blower speed increases with engine speed the value of the air current becomes greater when an augmented cooling effect is desired. Among the advantages stated for air cooling the greatest is the elimination of cooling water, which is a factor of some moment. In the temperate zone, where the majority of automobiles are used, the weather conditions change in a very few months from the warm 450 The Modern Gasoline Automobile summer to the extreme cold winter, and when water-cooled systems are employed it is necessary to add some chemical substance to the water to prevent it from freezing. The substances commonly em- ployed are glycerine, wood alcohol, or a saturated solution of calcium chloride. Alcohol has the disadvantage in that it vaporizes readily and must be often renewed. Glycerine affects the rubber hose, while the calcium chloride solution crystallizes and deposits salt in the radiator and water pipes. Obviously the elimination of water and the use of air cooling will provide a system that will be fully as effective during the extreme Air Pip. Fig. 233. Air- Jacketed Prayer-Miller Engine Used in Kelly Trucks Cooled by Air Currents Directed Over Cylinders by Positive Air-Blower System. cold weather as it is during the more favorable summer season. It would seem that air-cooling methods could be applied to advantage in commercial vehicle power plants which must be capable of efficient service under widely varying conditions. One of the disadvantages of an air-cooling method as stated by those who do not favor this system is that engines cooled by air cannot be operated for extended periods under overloads or at very high speed without heating up to The Modern Gasoline Automobile 451 such a point that premature ignition of the charge may result. The water-cooling systems, at the other hand, maintain the temperature of the engine more nearly constant than is possible with an air-cooled motor, and an engine cooled by water can be operated under condi- tions of inferior lubrication or poor mixture adjustment that would seriously interfere with proper and efficient cooling by air. Air-cooled motors, as a rule, use less fuel than water-cooled en- gines because the higher temperature of the cylinder does not permit of a full charge of gas being inspired on the intake stroke. As special care is needed in driving an air-cooled car to obtain satisfactory re- suits and because of the greater difficulty which obtains in providing proper lubrication and fuel mixtures which will not produce undue heating, the air-cooled system has but few adherents at the present time and practically all automobiles, with but very few exceptions, are provided with water-cooled power plants. CHAPTER VIII Utility of Clutches and Gearsets Defined Why These Vital Components of the Transmission System Are Needed on Gasoline Motor-driven Vehicles Conventional Forms of Cone Clutch and their Practical Application Characteristics of Three- and Five-plate and Multiple-disk Clutches Function of Gearset Types of Speed Changing Mechanism The Fric- tion Transmission Planetary and Individual Clutch Types Progressive and Selective Sliding Gearsets Typical Speed Changing Mechanisms Out- lined. ONE of the important functions making for efficient operation of the gasoline motor car is the method of power transmission em- ployed. While power plant efficiency is an important factor and one that should be conserved to the utmost, it is well to remember that the actual power of the car is not the rated power of the engine but the amount of energy exerted at the point of contact between the traction members and the ground. A 60 H. P. car in which there is a 30% loss in power transmission is not as efficient as a vehicle of but 45 H. P. which delivers the power to the rear wheels with but 10% loss. Under the conditions stated the rear wheels of the lower-powered car would actually receive more useful effort than the driving members of the high-powered vehicle, and the energy is supplied with less stress on the various parts and with a lower fuel consumption. The attention of mechanical engineers had been directed to the efficient transmission of power long before the motor . car was com- mercially practical. As a result many ingenious systems which had been applied in standard mechanical work and for driving the machine tools of manufacturing establishments have been readapted for use in motor-car propulsion. One who has studied the subject can easily trace the evolution from the crude forms of a decade ago to the perfected types used in modern automobiles. The problem of power transmission in motor cars was one that was not easily solved, 452 453 454 The Modern Gasoline Automobile and much experimenting was necessary before the perfected forms of the present day were evolved. A typical power-transmission group such as employed in the modern gasoline automobile is depicted in Fig. 234. In this the power is applied to the crank shaft of the motor and from thence it is delivered to the motor fly wheel which forms the female member of a friction clutch. The male member of the clutch is coupled to the change-speed gearing and this in turn is joined to the driving pinion in the rear axle by a length of shaft. The driving pinion delivers its power to a bevel-driving gear which is carried by the differential casing in the rear axle housing. From the differential gear independent shafts or axles drive the rear wheel hubs. The function of the clutch is to permit the engine to be run in- dependently of the transmission gearing when desired. The engine can drive the car only when one of the sets of gears in the gearset and the clutch are engaged simultaneously. For example, if the clutch is out or released, even if the gears were in mesh in the change-speed device, the rear wheels would not be turned until the clutch cone was allowed to engage the female member formed in the fly-wheel rim. At the other hand, when the parts are as shown with the clutch in engagement and the speed gears out of mesh the engine can still be revolved without turning the rear wheels. Why Clutch Is Necessary. In order to secure a better understand- ing of the general requirements of clutching devices it will be well to consider the conditions which make their use imperative when a motor car is propelled by a hydrocarbon motor. If a steam engine or an electric motor are installed as prime movers it is not necessary to include any clutching device or gearset between them and the driving wheels, and these members may be driven directly from the power plant if desired. With either of the forms mentioned the power is obtained from a separate source which may be uncoupled from the motor by the simple movement of a throttle valve or switch lever. Steam and electric motors are also capable of delivering power in excess of their rating and are more flexible than internal combus- tion power plants. If steam is the motive agent it is generated and contained in a special device known as a boiler, and the amount of power delivered The Modern Gasoline Automobile 455 In the engine to which the boiler is connected will vary with the amount of steam admitted and its pressure. If the steam supply is interrupted entirely the engine and the car which it drives are 1 > n alight to a stop. When it is desired to start again a simple move- ment of the throttle-valve lever will permit the steam to flow from the holler to the engine cylinders again and the vehicle is easily set in motion. If it is desired to reverse the car the steam flow is re- versed by a simple mechanical movement and the engine will run in the opposite direction to that which obtains when. the car is driven in a forward direction. If an electric motor drives a vehicle the electrical energy is se- (ii red from a group of storage batteries. W r hen these are fully rh urged varying amounts of electric current may be drawn from them and allowed to flow through the windings of the field or arma- ture of the motor and different ratios of power or speed obtained. The vehicle is easily started by completing the circuit between the motor and the source of current and stopped by interrupting the sup- ply of electrical energy. As the flow of electricity can be reversed easily by a switch the car may be driven backward or forward at will, and as the speed may be easily varied by changing the value of the current strength there is no need of speed changing or reversing gears. When a gasoline engine is fitted, conditions are radically different than with either a steam or electric power plant. The power devel- oped depends upon the number of explosions per unit time and the energy augments directly as the number of explosions and revolutions of the crank shaft increase. It is not possible to start a gasoline engine when under load because the power is obtained by the com- bustion of fuel directly in the cylinders, and as there is no external source of power to draw from it is obvious that the energy derived depends upon the rapidity with which the explosions follow each other. It has been demonstrated that a certain cycle of operation is necessary to secure gasoline-engine action and it is imperative that the engine revolves freely until it attains sufficient speed to supply the lor(jue or power needed to overcome the resistance that tends to prevent motion of the car before it can be employed in driving the vehicle. Then, again, it is very desirable that the vehicle be started or 456 The Modern Gasoline Automobile stopped independently of the engine. With a steam or electric motor the vehicle may be started just as soon as the driving power is ad- mitted to the prime mover, but with a gasoline engine it is customary to interpose some device between the engine and driving wheels which make it possible to couple the engine to the wheels or driving gearing and disconnect it at will. The simplest method of doing this is by means of some form of clutching device which will lock the driving shaft to the crank shaft of the engine. Clutch Forms and Their Requirements. Clutch forms that have been applied to automobile propulsion are usually of the frictional type, though some have been devised which depend upon hydraulic, pneumatic, or magnetic energy. Thqse which utilize the driving properties of frictional adhesion are most common and have proven to be the most satisfactory in practical application. The most impor- tant requirement in considering clutch forms is that such devices- must be capable of transmitting the maximum power of the engines to which they are fitted without any power loss due to slipping. Such a clutch must be easy to operate and but minimum exertion should be required of the operator. When the clutch takes hold the engine power should be transmitted to the gearset and driving means in a gradual and uniform manner, or the resulting shock may seriously injure the mechanism. When released it is imperative that the two portions of the clutch disengage positively so that there will be no continued rotation of the parts after the clutch is disengaged. The design should be carefully considered with a view of provid- ing as much friction surface as possible to prevent excessive slipping and loss of power. It is very desirable to have a clutch that will be absolutely silent whether engaged or disengaged. If the clutch parts are located in an accessible manner it may be easily removed for inspection, cleaning, or repairs. It is desirable that adjustment be provided, so a certain amount of wear can be compensated for with- out expensive replacement. A simple, substantial design with but few operating parts is more to be desired than a more complex de- vice which may have a few minor advantages, but which is more likely to cause trouble. The friction clutch in its various efficient types is the one that more nearly realizes the requirements of the ideal clutch. As a result The Modern Gasoline Automobile 457 this form is now universally recognized by automobile designers, and all standard gasoline automobiles utilize some form of friction clutch. These devices are capable of transmitting any amount of power if properly proportioned, and permit of gradual engagement and positive disconnection. Most friction clutches are simple in form, easily un- derstood, and may be kept in adjustment and repair without difficulty. How Friction Clutches Transmit Power. To illustrate the trans- mission of power by the frictional adhesion of substances with each other we can assume a simple case of two metal disks or plates in contact, the pressure existing between the surfaces being due to the weight of one member bearing upon the other. If the disks are not too heavy, it will be found comparatively easy to turn one upon the other, but if weights are added to the upper member a more decided resistance will be felt which will increase directly as the weight on the top disk and consequently the pressure between the disks increases. It may be possible to add enough weight so it will be practically im- possible to move one plate without turning the other. It is patent that if one of these plates was mounted rigidly on the engine shaft and one applied to the transmission shaft so that it had a certain amount of axial freedom and pressure of contact was maintained by a spring instead of weights, a combination capable of transmitting power would be obtained. The spring pressure applied to one disk would force it against the other and one shaft could not turn without producing a corresponding movement of the other. Materials Employed to Increase Frictional Adhesion. The main object of engineers in designing a clutch is to increase the amount of friction adhesion existing between the parts as much as possible. The transmitting efficiency of the clutch will vary- with the coefficient of friction between the surfaces and the more the friction between them the more suitable the clutch will be for transmitting power. A metal usually forms one frictional surface in all forms of clutches, and some types have been designed and used successfully in which all friction surfaces are metals. The materials of a metallic nature commonly used are cast iron, aluminum and bronze castings, and sheet steel and bronze, usually in the form of thin-stamped disks. The nonmetallic frictional ma- terials generally used are leather,, asbestos fabrics, textile beltings, 458 The Modern Gasoline Automobile and cork. Leather is the best lining or facing for clutches where the frictional area is large. When used it must be kept properly lubricated and soft, as if it becames dry it will engage very suddenly and clutch action will be harsh. At the other hand, care must be taken not to supply too much lubricant or the coefficient of friction will be reduced to a low point and the surfaces will slip. Oak-tanned leather is generally used because it has good wearing qualities, is a very resilient material, and possesses a very satisfactory degree of frictional adhesion when pressed against a cast-iron member. As- bestos fabrics are being applied in many forms of dry plate clutches and have been used to some extent in facing the male member of cone clutches. These are not as elastic as leather and unless some auxil- iary-relieving member is employed they will grip suddenly and un- desirable harsh clutch action obtain. When cork is used it is inserted in the metal surface in suitable holes which are machined to receive the inserts. Cork possesses pe- culiar qualities which make it very suitable for use in a clutch. It has perhaps the highest coefficient of friction of any of the materials employed, is not materially affected by either excessive lubrication or lack of it, and possesses very desirable wearing qualities. A clutch fitted with cork inserts will engage gradually and power will be trans- mitted to the rear wheels without shock or jar. It is the lightest and most elastic of the solids. In application cork must be used as an in- sert, because it is too brittle to be used in sheet form with any degree of success. When applied to a clutch the cork always works alone at low or medium pressures and at high pressures the other surfaces become engaged. This is given as the reason for the excellent wearing qual- ities of such combination surfaces, and when corks form a relatively large proportion of one of the contact surfaces they prevent cutting, no matter whether there is lubricant present or not. Then again, in the presence of a lubricant, which would obviously cause slippage between plain metallic or other surfaces, the corks so largely increase the total frictional adhesion that slippage is almost impossible. Opinions vary among designers regarding the most suitable ma- terials to use, though the selection of frictional material depends in most cases upon the type of clutch used. The large majority who The Modern Gasoline Automobile 459 favor the cone clutch employ a leather and cast iron combination and in many cases cork inserts are also employed. Metal to metal surfaces are the rule in multiple disk or plate clutches of small diameter, though as a general thing when a lesser number of plates of large diameter are used cork inserts or an asbestos fabric facing are invari- ably provided on one set of plates. Gearset Driving Member. Crankpin. Fig. 235. Sectional View of Cone Clutch Having Female Member Formed In- tegral with Fly- Wheel Rim. Forms of Cone Clutches Outlined. A simple and efficient form of cone clutch is shown at Fig. 235. This consists of three main parts, the female member, which is machined integral with the fly wheel, a 460 The Modern Gasoline Automobile corresponding male member, which fits into it, and a spring to main- tain contact between the surfaces. The fly wheel is attached to a flange forged integral with the end of the crank shaft by suitable screws. The male member is a truncated cone of metal faced with leather. The female member may be machined integral with the fly wheel, as shown at Fig. 235, or it may be applied to the fly-wheel rim by means of bolts, as outlined at Fig. 236. Experience has demonstrated that cast iron and leather make a very good wearing combination, and the tendency to use cork inserts to prevent harsh engagement is growing at the present time. Plain metal-to-metal surfaces are not suitable with this form because they would grip too suddenly and would soon slip if there was a thin film of oil between the surfaces. It will be noted that in either case frictional contact between the clutch cone and fly-wheel rim is main- tained by the use of a coil spring which is backed by a ball-thrust bearing in order to relieve the operating mechanism of any torque strain when the clutch is disengaged. In the cone clutch shown at Fig. 235, the male member is carried by a hub portion to which it is bolted, concentric with an annulus which bears on the crank-shaft extension. One end of the spring bears against the closed end of the annulus while the other end is held by the ball-thrust washer and nut screwed on to the end of the crank shaft. The spring pressure in this case keeps the cone seated by pushing it directly toward the crank shaft. When it is desired to release the clutch the operating pedal is depressed in such a manner that it swings on the fulcrum point and moves the clutch cone and the annulus member by which it is supported back so the clutch cone is pulled away from the fly wheel and the spring compressed. Some form of Oldham coupling or sliding joint is carried by the gearset driving member and is attached to the shaft extending from the gear case. When the spring pressure forces the clutch cone into engage- ment with the fly wheel, the assembly turns as a unit and the gear- set is driven by the engine crank shaft through the medium of the clutch and the gearset driving member which is attached to the clutch cone. When the cone is pulled away from the fly wheel the annulus which carries the gearset driving member remains stationary and the crank-shaft extension revolves in it. The Modern Gasoline Automobile 461 The clutch outlined at Fig. 236 differs from that previously shown in that the cone is inverted and the spring pressure is employed to Retention Bolt. , Flywheel Rim Female Member. Male Cone. Fig. 236. Cone Clutch Design with Female Member a Separate Casting Bolted to Fly- Wheel Rim. push the cone away from the fly wheel to engage it. The cone is carried at one end of the transmission shaft and revolves idly when it is pushed toward the fly wheel so that it is not in contact with the 462 The Modern Gasoline Automobile female member. In the cone clutch previously described the female member was machined in the fly-wheel rim. In that outlined at Fig. 236 the female member is a separate easting bolted to the fly- wheel rim. Typical designs of clutch cones and methods of fastening the friction facings to the cone castings are shown at Fig. 237. In that shown at A a combination of leather facing and cork inserts is employed. The leather is secured to the cast aluminum cone by means of rivets and the cork inserts are forced into recesses cast into the cone member. At B the practical method of retaining the leather facing employed on "White automobiles is illustrated. Cork Inserts Fig. 237. Typical Cone Clutch Male Members, Showing Methods of Attaching Leather Facing to Cone Casting. A Pope-Hartford Clutch Cone Faced with Leather and Cork Inserts. B White Cone Uses Leather Band Held in Place by T Bolts. When the leather facing is riveted to the cone rim considerable labor is involved in removing it after it has worn to such a point that re- placement is necessary because the large number of rivets must be driven out before the leather can be removed. The leather band which forms the friction facing of the cone at B is held by a number of T head bolts which pass through the cone rim and which seat into longitudinal grooves cast into the periphery of the cone member. These are of sufficient depth to prevent the heads of the bolts rub- The Modern Gasoline Automobile 463 bing against the female member of the clutch and only the leather facing acts as a driving surface. When the leather becomes worn it is a comparatively simple matter to remove the T bolts and put a new leather band in place. On some cone clutches of European design the endeavor has been made to use metal-to-metal surfaces by housing the cone in an oil- Outch Release. 'Lever 'utch Co/ie Fig. 238. Cone Clutches of English Design. A Metal-to-Metal Surfaces in Oil-Tight Case. B Method of Holding Parts in Contact with Adjustable Springs. tight casing so that it worked in a bath of lubricant. The lower co- efficient of friction existing between lubricated surfaces is compen- sated for by increasing the spring pressure. Such a clutch is shown in section at Fig. 238, A. The clutch case is formed of two members, one of these being the fly wheel, which is attached to the crank-shaft flange by bolts, the other is a cast casing, which is bolted to the fly- wheel rim on its face. The clutch cone is attached to a sliding shaft which telescopes on to the projecting end of the crank-shaft extension and which slides through an oil-tight bearing carried by the clutch cast- wliii-h is bolted to the fly-wheel rim. The spring thrust is taken at one end by the clutch casing and bears against a ball-thrust 464 The Modern Gasoline Automobile washer which seats against the flange to which the clutch cone is attached. The female member is machined in the fly wheel and does not differ from conventional forms. Another form of English derivation is shown at Fig. 238, B, this differing from those previously described only in the method of ap- plying the spring pressure. A three-arm spider carries three studs spaced at 120 degrees which also pass through bosses on the clutch cone. The spider is kept in place by a ball-thrust bearing retained on the fly-wheel hub by a clamping nut screwed on a thread cut at the end of the fly-wheel-retaining member which serves to keep the fly wheel in place, as well as forming a backing for the thrust bear- ing. The studs which project through the clutch cone have nuts threaded on the outer ends, and a spring is mounted outside of each clutch cone boss in such a way that it presses against the nut on the end of the stud and presses the cone into engagement with the fly wheel. The drive is interrupted by pulling the cone out of engage- ment in the usual manner. One of the disadvantages of the cone clutch, unless it is exception- ally well designed, is that it is likely to engage harshly if the leather facing becomes charred or hard from any other cause. When cork inserts are used in connection with the leather, a more gradual en- gagement is secured, even when the leather is dry, than would be possible without their use. Some designers have sought to secure easy engagement by using a number of auxiliary friction pads at- tached to the cone periphery, while others have been satisfied to use springs under the clutch leather which would raise it at a number of points around the periphery of the clutch cone. The object of this is to have a limited area of the leather surface engage the female member before the full spring pressure is exerted to bring the entire frictional surface in contact. The clutch shown at Fig. 239, which has been used on Columbia automobiles, is a conical type having a number of auxiliary friction pads extending through the periphery of the cone and projecting slightly above its surface. These are kept in place by auxiliary springs of the coil type. When the clutch cone is first engaged these friction shoes will engage the surface of the female member at a number of points and then when full spring pressure is exerted it The Modern Gasoline Automobile 465 will overcome the resistance of the small radial springs and the fric- tion blocks will be depressed so they will be flush with the surface of the male member which then takes the drive. The cone clutch is one of the most popular forms and has received general application, and its simple construction enables the motorist to easily understand its action. As there are but few parts there is but little liability of the cone clutch giving trouble if the leather Clutch Cone. Clutch Spring. Fig. 239. Columbia Clutch Employs Friction Shoes to Grip Fly Wheel Before Cone is Fully Engaged, to Secure Gradual Application of Power. surface is kept in proper condition. The chief disadvantage advanced against cone clutches is that they are more bulky than other forms of equal capacity. The large size of the members of a cone clutch tend to make it " spin " after it is disengaged. The natural tendency of a body in motion is to continue in motion until stopped by some external force, which property is known as " inertia." If two wheels of the same weight are set in motion by the expen- 466 The Modern Gasoline Automobile diture of equal amounts of energy the one that has the weight carried nearer the rim or which is larger in diameter will revolve the longest. The male member of a cone clutch, when released, will have a ten- dency to continue to revolve even when the driving pressure is re- lieved. When sliding gearsets are employed to obtain the various speed ratios it is imperative that the engine be entirely disconnected from the main shaft of the change-speed gearing before any attempt is made to shift the gears. If the sliding members are moved without first disconnecting the shafts from the engine it would be very diffi- cult to engage them and it might result in stripping the teeth from the gears. The average cone clutch is of large diameter if much power is to be transmitted because the two surfaces in contact are comparatively narrow. When the clutch is released considerable energy has been stored in the rim of the cone and its tendency is to keep revolving and carry the shaft of the gearset to which it is attached at the same speed. In some cases it is difficult to shift the gears until the motion of the shaft ceases and it is either necessary to wait until the momentum of the clutch cone becomes less or to apply some form of brake which will stop the cone from rotating. Such brakes are usually interconnected with the foot pedal and act only when the clutch is fully disengaged. Cone-clutch efficiency depends on a number of factors, chief among which is the angle of the cone. The greater the angle the more spring pressure required because the wedging effect of a large angle is not as pronounced as when more gradual tapers are employed. Most cone clutches have the cone tapering at an angle of 12^ degrees and is not considered good design to use a lesser angle because the wedging effect may make it extremely difficult to release the clutch. At the other hand, angles much greater than 15 degrees make it necessary to use excessive spring pressure to maintain proper frictional adhesion between the parts. Three- and Five-Plate Clutches. A number of cars are provided with clutches composed of three or more plates of large diameter instead of the use of two cone members. It is claimed that these forms make for very easy engagement and that they will give a very prompt releasing action when the surfaces are separated. The usual The Modern Gasoline Automobile 467 construction is to use two driving members which are carried around by the fly wheel which clamp against a central-driven member which drives the gearset shaft. These clutches are very effective, but one of the chief disadvantages is the same as that advanced against the cone clutch and that is the inertia of the driven member when re- leased. When these clutches are fitted it is desirable that they be provided with some form of a brake to bring them to a stop as soon as disengaged. Adjusting: Screw. Driving Plate. Clutch Spring Throwout Stud. _A Fly Clutch Spring. Crankpin. Fulcrum of Foot Pedal. Clutch Spring Pressure and Driving Plate. Driven Plate. Driving Plate. Fig. 240. Three-Plate Clutch Utilized on Knox Motor Cars Uses a Central Driven Plate Studded with Cork Inserts. A three-plate clutch which has been used successfully on Knox automobiles is shown at Fig. 240. In this construction the clutch springs are spaced at equal distances around the periphery of the fly wheel and bear against a pressure plate which is carried around by studs placed just outside the springs. Two driving plates are provided 468 The Modern Gasoline Automobile and these clamp a single-driven member attached to a revolving sleeve to which the gearset driving shaft is keyed. The pressure of the springs against the pressure plate holds the driven plate firmly against the outside driving plate. When it is desired to release the clutch the pedal is depressed and it pushes the clutch throw-out levers toward the fly wheel so the clutch spring throw-out studs push the pressure plate away from the driven plate and allow it to revolve independent of the clutch. The clutch throw-out studs perform a double duty in that they also act as driving members for the two driving plates. The driven plate is provided with a large number of cork inserts to increase its frictional adhesion. Flywheel.-"" -Driving Stud. -Driving Plate. -Outer Driven Plate. Bell Crank. Clutch Brake Pad. Clutch Throwout Lever. earset Shaft Driving Coupling. Clutch Brake Drum. Toggle Link. Adjusting Screw. Fig. 241. A Three-Plate Clutch Equipped with Friction Brake to Arrest Motion of Driven Member when Clutch is Released. Another form of three-plate clutch in which there are two driven plates and one driving member is shown at Fig. 241. The driving plate is carried around by a number of studs spaced around the fly- The Modern Gasoline Automobile 469 wheel-rim face. The driven member nearest the fly wheel carries a number of arms to which, small bell cranks are fulcrumed. These Flywheel. Flywheel Stud. Driven Plates. Adjusting Screw. Clutch Throwout. Driving Plates. Driving Stud. Fig. 242. Five-Plate Clutch which Employs Two Driving Members Attached to Fly Wheel and Three Driven Plates. arms also act as a support for the outer driven plate. The clutch spring bears against a sliding member which forces the ends of the 470 The Modern Gasoline Automobile bell crank to which it is connected by a series of toggle links out- wardly, and clamps the driving plate firmly between the inner and outer driven plates. When the clutch spring is depressed the bell cranks drop back and the pressure between the driving plate and the faces of the driven members is relieved. When this condition exists the driving plate turns with the fly wheel but does not pro- duce movement of the driven members to which the gearset shaft is attached by a semiuniversal driving coupling. When the clutch throw-out lever is moved away from the fly wheel to release the clutch it brings a small brake pad in contact with a drum carried by the driven member and stops its rotation. When the parts are as shown in illustration, the driving plate is firmly clamped between the driven members and the power of the engine is being transmitted directly to the gearset shaft. In order to obtain more driving surface some designers have used five plates instead of three. A five-plate clutch which operates on the same general principle as the three-plate type previously de- scribed is shown at Fig. 242. In this, two driving plates are carried by studs set into the fly-wheel face and the three driven members are kept in engagement by means of bell cranks and toggle-link action. The reason that five disks are used instead of three is that the aug- mented surface makes it possible to reduce the spring pressure to some extent and makes for easier operation when it is desired to dis- engage the clutch. When the driving contact between the clutch plates is interrupted the member to which the gearset shaft is attached is kept stationary and the fly-wheel hub and crank-shaft extension revolve freely because anti-friction bearings of the ball type are interposed between the members. Features of Multiple-Disk Clutches. Power transmission by plates is sometimes accomplished by using a large number of small diameter disks instead of the smaller number of large plates. The multiple- disk type offers several advantages not found in other forms, as it is the most compact form of clutch. The required contact area is ob- tained by using a multiplicity of comparatively small surfaces in preference to two large ones as is the case with the cone clutch or the greater number possible when three- or five-plate clutches are employed. The Modern Gasoline Automobile 471 The type of multiple -disk clutch that seems to be most widely employed consists of a number of soft steel disks which sometimes alternate with others of different material such as phosphor bronze. One set of these disks is driven by the engine while the remaining plates are attached to a floating member to which the transmission shaft is joined. Pressure is usually obtained from a coil spring which acts against one of the disks, which in turn acts upon the neighboring one. It is common practice to house a clutch of this type in an oil-tight case, which insures that the members will always be kept in an oil bath. Oil performs the dual function of securing easy engagement by interposing a cushion between the metal elements and also to prevent wear because of its value as a lubricant. As multiple-disk clutches are usually of small diameter, the inertia of the driven member is small compared to that of a 'cone or large plate type, and the spinning tendency is reduced. The spring pres- sure is usually sufficient to squeeze the oil from the plate as soon as engagement is fully made and a metal to metal contact then obtains. The fact that the lubricant is gradually forced out and that there will be a certain amount of slipping as long as any of the lubricant remains means that the power will be applied in a gradual manner even if the clutch is carelessly operated. While a multiple-disk clutch does not have a tendency to spin because of inertia, the plates may sometimes refuse to disengage be- cause of a partial vacuum existing between them, produced when the oil film was forced out. This sometimes causes the plates to adhere together. This trouble is rare in well-designed clutches and is sel- dom present unless poor lubricating oil is used between the plates. This drag and consequent trouble in shifting gears is more apt to occur on forms which employ flat-stamped plates without spring tongues to separate them when the spring pressure is relieved. ' Mul- tiple-disk clutches are sometimes provided with plates having cork inserts, while others have a number of the disks faced with some friction material such as the asbestos-wire fabric and are designed to run dry instead of in an oil bath. A typical multiple-disk clutch is shown at Fig. 243. In this member the clutch case is cast integral with the fly wheel and forms the fly-wheel hub. A series of disks are carried by a driving drum 472 The Modern Gasoline Automobile and are kept in engagement with those carried around by the fly wheel by means of pressure derived from a coil spring which is let into a bored-out recess at the end of the crank shaft. The clutch depicted is intended to run in oil and a number of the plates are Flywheel. Disc Assembly. Fig. 243. Typical Multiple-Disk Clutch Assembly. The Form Illustrated Used on Some of the Hudson Cars. provided with cork inserts. The multiple-disk clutch depicted Fig. 244 is that used on Franklin cars, and is a form in which all metal plates running in oil are used. That depicted at Fig. 245 is Fig. 244. Multiple-Disk Clutch Utilized on Franklin Automobiles is Housed in Blower Fly Wheel. Parts are Shown Separated to Make Construction Clear. Driving Discs. Plate with Cork Inserts. Fig. 246. Clutch of Premier Cars Uses Multiple Disk Studded with Cork In- serts as Driving Members, and Plain Metal Plates as Driven Elements. 473 474 The Modern Gasoline Automobile used on Premier cars and one set of plates is provided with a number of cork inserts to promote easy engagement, positive drive, prompt release. While the clutch forms described are the most common, a few cars have been provided with internal expanding band clutches or external constricting band forms. The internal member consists of a steel band or shoe faced with leather or other frictional material or provided with cork inserts which expands against the inner periph- ery of a drum integral with the fly wheel. The band is expanded by spring pressure which spreads the driven member either by toggle linkage or a right and left hand quick-acting screw. Planetary gearsets employ external constricting bands to stop rotation of the gear drums, but these should properly be considered under the head of brakes rather than clutches. The disadvantage of either internal or external band clutches is that they are very hard forms to balance and the internal expanding band is especially sus- ceptible to the influence of wear and oil between the surfaces. The external band provides a very gradual clutching action, but owing to the difficulty in balancing it because of the unsymmetrical operating mechanism usually employed, it has not been used to any extent in this country. With the forms described no difficulties are present as relates to balancing, and as the band forms have no apparent ad- vantages when compared to the better developed cone and plate types there seems to be no reason for further development of forms which are good in theory but hard to apply in a practical manner. Why Change-Speed Gearing is Necessary. Those who are familiar with steam or electricity as sources of power for motor vehicles may not understand the necessity for the change-speed gearing which is such an essential component of the automobile propelled by in- ternal combustion motors. In explaining the reason for the use of the clutch it has been demonstrated that steam or electric motors were very flexible and that their speed and consequently the power derived from them could be varied directly by regulating the amount of energy supplied from the steam boiler or the electric battery, as the case might be. If, for example, we compare the steam motor with the explosive engine it will be evident that the power is produced in the former The Modern Gasoline Automobile 475 by the pressure of steam admitted to the cylinders as well as the quantity and the speed of rotation. When the engine is running slowly and a certain amount of power is needed more steam can be supplied the cylinders and practically the same power obtained as though the steam pressure was reduced and the engine speed in- creased. The internal combustion motor is flexible to a certain de- gree, providing that it is operating under conditions which are favorable to accelerating the motor speed by admitting more gas to the cylinders. There is an arbitrary limit, however, to the power capacity or the mean effective pressure of the explosion, and beyond a certain point it is not possible to increase the power by supplying vapor having a higher pressure as is possible with a steam engine. In an explosive motor we can increase the power after the maxi- mum throttle opening has been reached only by augmenting the number of revolutions. Whereas it is possible to gear a steam engine or an electric motor directly to the driving wheels, it is not possible to do this with a gasoline engine, and some form of gearing must be introduced between the motor and the driving wheels in order that the speed of one relative to the other may be changed as desired and the engine crank shaft turned at speeds best adapted to produce the power required, and to allow the rear wheels to turn at speeds dictated by the condition of the roads or the gradients on which the car is operated. It is customary in all automobiles of the gasoline-burning type, where combustion takes place directly in the cylinders, to interpose change-speed gearing which will give two or more ratios of speed between the engine and the road wheels. As it is not possihle to reverse the automobile engine utilized in conventional cars, it is neces- sary to add a set of gears to the gearset to give the wheels a reverse motion when it is desired to back the conveyance. Many methods of varying the ratio of speed between the engine and traction members have been evolved, but few speed-changing mechanisms have survived. At the present time the majority of automobile makers employ sliding gear transmissions which are al- most invariably of the selective type. One or two cars are fitted with simple face friction gearing and a limited number provide two for- ward speeds and a reverse motion by using planetary gearing. 476 The Modern Gasoline Automobile At one of the recent automobile shows held at Xew York, 385 models of cars were exhibited, and of this number but a. very small percentage used change-speed gearing that differed radically from standard practice. Of this number 347 models were equipped with selective sliding gear transmissions and six cars used progressive slid- ing gearing. Thirteen models utilized planetary transmissions and friction change-speed gearing was supplied in nineteen instances. While the sliding gear form of transmission is without doubt the most unmechanical and brutal of all speed gearing, if considered from a purely theoretical viewpoint, the very satisfactory service which is secured in actual use justifies its general application, especially at the present time when engineers are so thoroughly conversant with details of design and motor-car drivers have been so well trained to operate gears of this character with proper care. Face Friction Gearing. A form of gearing that has many ad- herents because of its simple design and easy operation employs two friction disks which are held together by sufficient pressure to cai c Fig. 246. Outlining Action of Simple Face Friction Gearing, which Combines Clutching and Speed-Changing Functions. one of these members to turn the other. This was one of the earliest forms of gearing used, and while it was abandoned for a time because of defects of a purely technical nature continual experiments made possible a combination of materials which gave satisfactory results in practice. The rolling traction, or friction transmission, as it is commonly called in its simplest form, is shown at Fig. .246, A. It consists of two disks or plates, one faced with an aluminum-copper alloy driven TJie Modern Gasoline Automobile 477 by the engine and a wheel which is provided with a strawboard fiber driving ring mounted on a cross shaft at right angles to the ( rank shaft of the power plant. The cross shaft is journaled in anti- friction bearings and the driven disk or plate can be moved axially so as to engage with different portions of the aluminum driving disk. The driving member is mounted on a sliding shaft which can be moved toward the driven member and held in contact by a definite amount of pressure or pulled away when it is desired to interrupt the drive. In this manner both clutching and spee'd-changing func- tions are combined in one simple mechanism. The method by which various speed changes may be secured is demonstrated at Fig. 246, B. The driven member is shifted across 'the face of the driving disk so it can engage different portions at varying distances from the center. As the wheel is moved from the center toward the outer periphery the speed ratios increase in proportion to the amount the disk is moved out. If the driven disk is moved over to the other side of the driving disk and past the central point a reverse motion will be obtained when driving contact is again established between the surfaces. To interrupt the drive the members are separated and when the faces are brought together the frictional adhesion permits one to drive the wheels. Assume that both disks are sixteen inches in diameter and that the driven member has moved away from center until it engages a point having a mean radius of two inches from the center line. The disk would be moved from position B in which it is placed, as shown in illustration, to position indicated by the dotted rectangle D. In this case the driving effect would be just the same as though a four-inch diameter wheel was engaged with the sixteen-inch diameter driven member. This would give a low gear ratio because the engine would be turning at four times the speed of the driven member. If driving contact was again broken and the driven wheel moved along the shaft until it occupied the position indicated by the rectangle E, the effect would be the same as though an eight-inch driving member \\a> turning the sixteen-inch driven wheel. This would give a higher ratio than in the case previously described, as the engine shaft would only turn at twice the speed of the driven member. If the driven member was moved so that it occupied position G, 478 The Modern Gasoline Automobile the highest speed would be obtained because the disks would be turn- ing at equal speed as one sixteen-inch wheel would be turning another one of the same diameter. If the disk was moved back to the other side of center or from position B, to that shown by the rectangle C, Driving Disc. Driven Disc. Drive Shaft. Engine. Driving Disc Slip Joint. N -Flywheel. Differential. Countershaft. Driven Wheel. Chain. Fig. 247. How Face Friction Gearing is Installed in Motor-Car Chassis. A Arranged for Shaft Drive. B Power Transmitted to Wheels by Side Chains. the driven wheel would be turned at one fourth the engine speed and in a reverse direction. This form of gearing is not generally used for high-powered cars because the driving wheel must be of large diameter and very bulky to transmit the higher powers. The amount of energy it is possible to transmit efficiently depends upon the nature and size of the sur- The Modern Gasoline Automobile 479 faces in contact and the amount of pressure which is exerted to bring the friction members together. When a friction transmission is us* 'i 1 it is usually applied in connection with single- or double-chain drives to the rear wheels, though forms have been devised where driv- ing by shaft and bevel gears is possible. The application of a friction transmission to a shaft-drive chassis is shown at Fig. 247, A. In this the double-opposed motor is mounted so the crank shaft is at right angles to the frame side member while the cross shaft on which the driven disk slides is parallel with the frame side. The aluminum-alloy driving disk is attached directly to the fly wheel of the motor, while the fiber-faced friction wheel is carried on a countershaft so journaled that the entire shaft may be swung over and bring the driven disk in contact with the driving member. A shaft serves to connect the driven disk shaft to bevel gearing in the rear axle. At Fig. 247, B, the method of installation when a double-chain drive is provided is shown, while at Fig. 248 the layout of a friction gearing employing single-chain drive is outlined. The relation of the parts to each other can be very easily understood by referring Fig. 248. Disposition of Important Elements of Simple Face Friction Gearing Adapted for Single-Chain Drive. to the illustrations. In the system depicted at Fig. 248 the double- cylinder engine is placed in the frame in such a way that the crank sluil't is parallel with the frame side member. The drive from the engine cr;uik shaft is through a sliding coupling at one end of the 480 TTie Modern Gasoline Automobile shaft which carries the aluminum driving disk. This memher is backed by a ball-thrust bearing which in turn forms part of a sliding sleeve or bushing connected to the small arm of a lever which is joined to the foot pedal. When the long arm of the lever is moved in the direction of the arrow the sliding coupling is pushed in a reverse direction and the pressure exerted against the aluminum disk brings it in contact with the fiber-faced wheel on the countershaft. The driven wheel is moved along the countershaft by means of a long bell crank, the short end of which goes to the control lever while the long end is employed to swing the fiber-faced wheel along the coun- tershaft. The drive from the countershaft is by means of chain and sprocket connection with a live rear axle. In the form shown at Fig. 247, B, the rear axle is a stationary member and the wheels are driven independently by means of sprockets carried by the axle shafts of the compound countershaft, which is in reality a live axle mounted on the frame members and carrying the differential gear. As the power transmitted is directly proportional to the pressure maintaining contact between the sur- faces it is imperative that the leverage employed to produce this pres- sure be very substantial and rigid. Tests have demonstrated that the best combination of surfaces is a strawboard fiber driving ring against an aluminum or copper-alloy driving plate, and these are the materials commonly used. This form of gearing has the advantage that it is easily handled by the novice and it is difficult to injure it by careless manipulation. The number of forward speeds provided are infinite, as the driven member may be moved across the driving face very gradually and engage driving circles which vary by small increments. The sur- faces must be kept clean and free from grease or the gearing will slip, and for this reason this form is not so generally used as one might suppose, if its value was judged only by its simplicity and ease of operation. How Planetary Gearing Operates. The planetary or epicyclic transmission is an easily operated form of speed gear that has been very popular on small cars. This has many features of merit, it provides a positive drive, and as the gears are always in mesh these members cannot be injured by careless shifting. Individual clutches The Modern Gasoline Automobile 481 are used for each speed and as the operation of the clutch occurs at the same time that the desired speed is selected the various speed changes desired may be easily effected by manipulating a single lever if desired. A typical planetary gearing of simple form which was formerly used on Oldsmobile cars, which were one of the earliest makes to Brake Drum. Engine Shaft. 1 Tf J V Clutch C w Speed and Reverse Bands. Planetary Gears. Fig. 252. Two-Speed and Reverse Planetary Gear Employed on Ford Auto- mobiles. and a similar member constricted around the reverse drum will give the reverse motion. The gearing is locked together by means of a face-friction clutch, which is pressed in contact with the slow-speed drum face by means of a high-speed locking cone and cone-operated The Modern Gasoline Automobile 485 dogs or bell cranks. The form shown is intended to work in connec- tion with shaft drive, and a universal joint is attached to the squared driving end. The planetary gearing shown at Fig. 252 is that used in Ford automobiles and its operation is similar to the forms previously de- scribed. In this mechanism, however, the master clutch which pro- vides the direct drive is a multiple-disk form composed of steel disks, which are kept in permanent contact and proper driving relation by means of a heavy coiled spring. The low and reverse speeds are obtained in the conventional manner by tightening the external con- tracting clutch bands, which are shown between the gearing and disk clutch. Planetary gearing has been very successful when properly designed (and installed, and its chief disadvantage is that it is very difficult to provide more than two forward speeds and one reverse. For this reason it can only be adapted to light cars which have a surplus of (power in the engine, or to heavy trucks where it is not so essential ! that a large number of speed ratios be provided as in touring cars. f Such gearing is not efficient on low and reverse speeds as considerable power is absorbed in friction, but when on the high speed or direct drive it is superior to any other form of change-speed gearing because the entire assembly is locked to the crank shaft, no gears are turning idly, and the weight of the gearing serves merely as an additional fly-wheel member. Considerable trouble was experienced with the (early forms because it was difficult to keep oil in the case, but in mod- ern forms special care has been taken in housing the reduction gears so these are constantly oiled, and both wear and noise, which were I formerly detrimental to the adoption of this form of gearing and which militated largely against its general use, have been eliminated. Individual Clutch Transmission. A form of gearset which com- bincs the good features of the planetary type in that the driving gears Ice always in mesh and which can be provided with any desired num- iber of speed ratios is known as the individual clutch type. In gear- .sets of this form one set of gears is carried by the countershaft and is fixed thereto while another set of gears, with which these members , revolve idly on the main driving shaft. A transmission of this type which has been applied successfully 486 The Modern Gasoline Automobile in motor-truck design is shown at Fig. 253. In this the power is delivered to a main shaft, which is supported on ball bearings and which carries a bevel pinion engaged with a bevel gear for driving the wheels at the rear end. The gears mounted on the main shaft are normally free to revolve independently from the shaft unless they are clutched to it by sliding positive jaw clutch members driven High and Intermediate and Reverse Clutch Clutch Fig. 253. Part Sectional View of Cotta Individual Clutch Transmission Designed for Heavy Motor Truck. by the main shaft. Any desired speed ratio may be selected by en- gaging the gear desired by means of the clutch carried at its side, thus causing it to turn with the shaft. When the clutches are placed as shown in illustration, the gears are neutral and' the driving shaft turns without producing movement of the bevel driving gears. If it is desired to engage the low speed the low and reverse clutch member is moved toward the front end of the gearset until it clutches the low-speed gear to the main shaft. The power of the engine is then applied to the countershaft through the constant mesh gears at the extreme front end of the gearset and as the main shaft is made in two pieces, the end of one member telescoping into the portion that carries the driving connection to the engine, the drive is back from the countershaft low-speed pinion to the big gear which has been clutched to the main shaft and which causes it to turn slower than the driving member attached to the engine. I The Modern Gasoline Automobile 487 To obtain a reverse ratio the low and reverse clutch is moved to flu' hark end of the transmission and the reverse gear is locked to the main shaft. To obtain direct forward drive the high and inter- mediate clutch member is pushed forward until it engages the teeth on the side of the constant mesh gear. This operation locks both portions of the main shaft together and causes that part to which the bevel driving pinion is secured to turn at the same speed of rotation as the driving end which is joined to the engine. The dutches are arranged in such a manner that only one can be used at a time and in addition to the positive clutches carried in the gear case | some form of master clutch, which is invariably of the friction type, must lie provided between the power plant and the gearset. t Chain. Countershaft. Constant Drive Chain. O Intermediate. Reverse Gears. Fig. 254. Individual Clutch Transmission Using Silent Chain Connection Be- tween Main and Countershafts for Forward Speeds and Sliding Spur Gears for Reverse Action. There is a growing tendency to apply the silent chain to positive individual clutch types of transmissions instead of utilizing direct gear connection. The application of silent chains to a gear box is sho\\ M at Fig. 254, and the sectional view which is shown at Fig. 255 kes the method of operation clear. The advantage of the silent inaivi 488 The Modern Gasoline Automobile chain when used in gear boxes of this character is that it provides a more silent drive than direct gear connection would. This is very valuable in the .case of heavy, low-powered cars such as omnibuses and commercial vehicles, where the gearing is frequently used and where the vehicles are operated for the most part under traffic con- ditions which make noisy operation undesirable. The method of operation when silent chains are used is exactly the same as though the drive was by spur gearing. Referring to the sectional view of the gear box given at Fig. 255, it will be seen that the power from the motor is delivered to a drive Countershaft Drive Gear. \ Intermediate. Low Pinion. .Countershaft. Reverse Pinion. Brake. High and mediate Shif Member. Idle Gear. Reverse Gear. Low and Reverse Shift Rod. Fig. 255. Sectional View of Individual Clutch Gearset with Silent Chains Re- moved to Show Arrangement of Gearing. sprocket in the interior of which the end of the main shaft telescopes and which is supported by suitable ball bearings. The countershaft mounted above the main shaft carries four gears, three of which are adapted to use silent chains, while the smallest member is a clash gear of the conventional pattern, employed only to obtain reverse speed. It will be observed that two gear members are carried by ball The Modern Gasoline Automobile 489 bearings at the center of the main shaft in such a way that they .revolve independently of that member unless they are clutched to it by the positive clutches keyed to the shaft. To obtain the reverse drive the large reverse gear is moved back in such a way that it engages the reverse pinion on the countershaft. The drive in this case is from the motor to the constant drive gear, forming part of the main shaft which turns the countershaft drive gear by means of a silent chain which is not shown in this view but which can be very clearly seen at Fig. 254. The countershaft is turning in the same direction as the motor and the spur gears used at the back end of the gearset are employed to reverse the motion. When the low speed is desired the low and reverse shift member is moved in such a manner that the idle gear is clutched to the shaft. When this condition obtains the drive is from the motor through the constant drive gears and from the countershaft by the low-speed pinion and the big gear which has been clutched to the main shaft and which serves to drive the universal joint con- nected to the bevel gearing in the rear axle. A movement of the high or intermediate shift member will give either of these speeds desired. The intermediate speed is obtained in exactly the same manner as the low speed except that the gear ratio is such that a higher ratio of drive is provided, while the high speed or direct drive is obtained by locking the two sections of the main shaft together. How Sliding Gearsets Operate. The majority of change-speed gearsets which have been generally fitted to automobile service are forms of sliding gear arrangements and may be divided into two main classes. In progressive sliding gearsets but one member is employed for all speeds and this is shifted along from one extreme position to the other. In the selective system it is possible to go into any one of the speeds or gear ratios desired without passing into other speeds and with but a limited movement of the shifting mem- bers. The sliding gear system was one of the first to receive general application in early forms of motor vehicles and in its primitive condition it was but a modification of the back gearing used on (crtain classes of machine tools, such as lathes, drill presses, etc. One 490 The Modern Gasoline Automobile of the advantages of this type when compared to other gear trans- missions is that it is possible to provide a greater number of speed changes and that there is a higher driving efficiency when on the lower ratios because but two pairs of gears are in mesh. An example of a progressive sliding gear transmission is depicted at Fig. 256, this providing three forward speed ratios and one re- Constant Mesh Gears. // Intermediate. Lever. Counter.' Engine End. Main Shaft. Sliding Member. Fig. 256. Arrangement of Gears in Progressive Sliding Gearset. verse. The various speed ratios are secured by moving the sliding member which is composed of two gears along the main shaft so that it engages successively the gears on the countershaft. When the sliding member is in the position shown, no gears are engaged and no power can be transmitted through the gearset. If the sliding member is moved toward the right so that it engages the small pinion under the reverse gear on the countershaft a reverse drive would be obtained. If the sliding member is shifted toward the left until the large gear member engages with the low-speed gear on the countershaft the lowest forward drive ratio is obtained. The Modern Gasoline Automobile 491 Continued movement of the sliding member toward the left will cause the small gear to engage with the intermediate pinion and produce a ratio of drive that will not be as fast as the direct con- Engine End. Countershaft. High and Intermediate Speed Shift Member. Fig. 257. Showing Application of Two Shifting Members on Main Shaft of Selective Sliding Gear Speed-Changing Mechanism. iicction but which is faster than the slow-speed ratio. When the sliding member is moved to the extreme left it serves to lock the tun portions of the main shaft together and a direct drive is ob- 492 The Modern Gasoline Automobile tained. The power from the engine is first delivered to the constant mesh gear which normally drives the countershaft and which re- volves around the main portion of the main shaft which telescopes into its interior. If the design of this gearset be compared to that outlined at Fig. 257, it will be evident that in the latter two shifting members are employed which have a smaller degree of movement than the single member of the progressive type. The reason that the selective system is generally preferred may be easily understood by referring to the comparison between the forms as shown at Fig. 258. In the progressive sliding gearset which is shown at A, the shifting member- High and Int. Shift Member Shifting Member for all Speeds. Direct./ s Slow. Intermediate. Fig. 258. Comparing Progressive and Selective Gearset Action to Demonstrate Advantages of the Latter Form. is shown engaged with the intermediate gear on the countershaft. If it is desired to pass into the reverse from this position the slow speed must be engaged before the reverse gear can be reached. The hand lever used to shift the gearing is moved back with one con- tinuous movement. For instance, if the gearing be in the reverse position and it is desired to engage the direct drive it will be neces- sary to pass the one shifting member to the low speed, past the in- termediate and from thence into the direct drive position. With the selective gearset which is depicted at Fig. 258, B, the plurality of shifting members provided makes it possible to go into any speed directly without passing through the others. For in- stance, the high and intermediate shift member is shown in the position at which the intermediate speed ratio is obtained. If it is The Modern Gasoline Automobile 493 desired to engage the high speed this member may be pushed directly into position so that the main shaft and the constant drive gear are locked together. If it is desired to go into reverse a simple movement of the operating or shifting member, which is guided by an H slot gated segment, will disengage the high speed and throw the other shift member into position by one simple movement. One of the advantages of this method is that it is much easier to engage the gears and that the liability of injuring the gear teeth by injudicious shifting is not as great as in the "progressive type. Another advantage of the selective system is that it permits a more compact construction and makes possible the use of shorter shafts which are stiffer than longer ones because the distance between points of support is not so great. Not only is the operation much easier but it is possible to obtain the varying speed ratios much more quickly than with the progressive system. The usual number of gear ratios provided is three forward speeds and one reverse motion. On some of the heavier touring cars four forward speeds are provided and when this is done engineers differ as to whether the direct drive should be on the third or fourth ratio. When the direct drive is on the third ratio the fourth speed is ob- tained by gearing up and the driving shaft revolves faster than the main shaft of the engine. When the fourth speed is a direct drive the crank shaft and the driving shaft turn at the same speed. Those who favor the former method contend that as most of the regular driving is done at a medium rather than at an extreme high speed the direct drive on the third is preferable to a direct drive on the highest ratio. The geared-up fourth speed can be used only when conditions are exceptionally favorable to high speed. If the highest speed was ol it ained by a direct drive the natural tendency of the motorist would be to use this most, but there would be many conditions where the ratio would be too high and one of the lower gears would have to be used. If the direct drive was obtained in the third ratio this would be employed the greater part of the time, and as there would be less wear on the gearing with the direct drive engaged it would !>' preferable to use this as much as possible. The question of gear ratio to use depends entirely upon local con- ditions and before determining the ratios of the gearing in the speed- 494 The Modern Gasoline Automobile changing mechanisms it is imperative that a definite relation be es- tablished between the speed of the driving shaft and the Toad wheels. When heavy pleasure cars use engines of moderate power the gear reduction is usually three and one half or four to one, this meaning that when the gearing is in the direct drive the engine crank shaft will turn three and a half or four times to one revolution of the driving wheels. On cars where the margin of power is large and where high speeds are desired the ratio may be but two and one half to one. If the car is geared too low, the engine must make a very high number of revolutions when on the highest speeds and use much more fuel than necessary. On the other hand, if the driving ratio is too high it will be necessary to change gears frequently because even moderate grades will make it imperative to use a lower ratio than that afforded by the direct drive. The body fitted to the car has a material bearing upon the gear ratios provided. The driving speed that would be entirely practical on a chassis fitted with a roadster body would be much too high if a limousine or coupe body was fitted to the same chassis. If the car is to be operated in regions where the conditions are not favorable, such as hilly sections, or where the highways are poorly developed, a much lower final drive ratio must be provided than where the roads are good and conditions favorable to higher speeds. The speed ratios when the low gears are engaged will vary from ten to one to such extremes as twenty-five to one. The intermediate speed usually varies from five to one to ten to one, and a third ratio in a four-speed gearset may vary from three to one to six to one, and in some gear- sets it may have a value of seven or eight to one. If the fourth speed is obtained by gearing up one may get a ratio of drive as high as two to one, though when the direct drive is on the fourth speed it is seldom higher than three to one. Most of the sliding gearsets have at least one of the speeds a direct drive, but some forms have been devised where the power is transmitted through gears at all ratios. A gearset of this type, which has been used in an English omnibus, is outlined at Fig. 259. This operates on the selective principle, but the drive at all speeds is through gears. Two shifting members are mounted on the main shaft. One of these carries two small gears, the other has two larger Modern Gasoline Automobile 495 members. When the highest speed ratio is desired, the largest gear on the main shaft is engaged with the smallest member on the counter- shaft and a? the. Tn the former the main shaft of the gearset is in the form of a quill or tube which surrounds one of the axle shafts and the countershaft is a separate member carried directly in back of the main shaft. When on the direct drive the high-speed shift member i> moved toward the left and locks the differential gear case firmly to the quill, which acts as the main shaft. When the parts are locked together in this manner a direct drive is obtained. The lower speed 504 The Modern Gasoline Automobile 505 ratios are obtained in the same manner as in any other selective transmission, the gears on the main shaft being moved to engage the corresponding members on the countershaft. The contention is made that this method of design makes for a more compact as- sembly as all parts are housed in one casing member. Most engineers who favor combining the rear axle and the trans- mission use the constmction outlined at Fig. 269. In this all parts are so clearly shown that the method of application should be suffi- ciently clear without lengthy description. The change-speed gearing is a conventional three-speed and reverse selective sliding gear type and the drive to the rear axle is by the usual bevel-gear connection. The various systems of driving and methods of manipulating the speed-change levers will be considered more fully in proper sequence. Transmission Gear for Four-Wheel Drive. When a four-wheel drive system is employed it is necessary to use a radically different form of gearset from that commonly employed in cars where a single drive shaft goes to a rear axle to which the tractive members are attached. A gearset of this type is clearly outlined at Fig. 269a, and its actual application to a four-wheel drive chassis is shown at Fig. 2696. The change-speed gearing is of the individual clutch type and provides three forward speeds and a reverse ratio by means of sliding jaw clutches which lock gears that are always in mesh with each other securely to the drive shaft. The main driving shaft is extended through a supplementary casing attached to that containing change-speed mechanism. A silent chain serves to transmit power from a suitable sprocket on the driving shaft to another member placed on the driven shaft below it. This driven shaft extends through the casing at both ends and the drive to the front and rear axles is by means of the usual propeller shafts and universal joints from the front and rear ends of the chain-reduction case respectively. In the chassis shown at Fig. 269&, the axles are different. The rear axle is a conventional form and the wheels are utilized for tractive pur- poses only. The front axle is a special construction, in which the wheels are driven by ball and socket joints which permit of their inclination to steer the vehicle without interfering with the power- tran?mision functions. Combination Gasoline-Electric Drive. One of the great ad van- 506 The Modern Gasoline Automobile The Modern Gasoline Automobile 507 508 The Modern Gasoline Automobile tages of the electric automobile outside of its silence and smooth operation is the ease Avith which the speed and power may be controlled. On the true gasoline type it is necessary to shift gears in order to attain various speed changes, and unless this gear shifting is very carefully done it may be possible to damage the transmission and also to impose shocks on the entire mechanical structure, due to too sudden engagement of driving gearing or clutches. While this defect is not serious enough to be a disadvantage of moment, at the same time it is evident that the operator of a gasoline car must be very competent and thoroughly familiar with the manipulation of the speed-changing and clutch-control lever. The various speeds are obtained by a simple movement of a controller handle, without shock or jar, when electric current is used for propulsion. This makes it possible for ordinary drivers to control the vehicle, because it does not require any special skill to move the controller handle, whereas it does take practice and experience to properly manipulate a sliding gear transmission and clutch. There are some general disadvantages to the application of elec- tric power alone, and it seems to be the general opinion of engineers all over this country and in Europe that gas power is more suited for commercial work than is electric power, if the latter is derived solely from storage batteries. An electric vehicle depending upon stored energy is not capable of the speed that can be made with a gasoline engine as a power plant. The range or radius of action of the average electric battery is apt to be somewhat limited, and one might easily imagine a condition, especially in a city or town of any size, where enough distance might be covered in the course of a day to prevent proper charging of the storage battery, and this, of course, would result in diminished efficiency as the battery charge became depleted. The writer does not mean to imply that electric power derived from a storage battery is impractical. On the contrary, many very effi- cient automobiles are propelled by this power. An ideal combination in which the main advantages of both gas and electric power are obtained is the combination or gasoline-electric system in which the prime mover is a gasoline motor which delivers its power to an electric generator instead of to the usual form of gear transmission. With this combination one is obliged to obtain a large The Modern Gasoline Automobile 509 510 The Modern Gasoline Automobile radius of action, inasmuch as the gasoline engine may be operated continuously as long as the supply of gasoline and oil is adequate, and by the use of the electric power to turn the wheels one is enabled to gain the main advantages, namely, easy control and simplicity of operation that would be obtained in electric automobiles. A very efficient tractor has been devised by the American and British Manufacturing Conrpany which is particularly suited for fire department and general commercial service, as it can be just as well adapted to use on existing wagons and all kinds of fire apparatus as to new fire engines and other machines. The construction is such that the change from horse-drawn to motor traction is a simple operation that does not require the vehicle to be out of commission very long. This tractor construction operates on the Hoadley system and gives excellent service because there is nothing radical in the design. Effi- ciency is obtained by an ingenious application of well-known mechan- ical elements. Among some of the advantages of this system as ad- vanced by the makers may be mentioned, extreme simplicity, mini- mum depreciation, because there are few parts that can wear out, and every part of the machine is unusually substantial. There is great flexibility of control as relates to power and speed. It possesses satis- factory hill-climbing ability, has superior traction and stability on slippery roads, and it can be steered and maneuvered without expendi- ture of undue energy. In addition to the points enumerated this sys- tem of construction also shares the advantages present with the trac- tor system of propulsion. These are that the body design will be independent of the mechanism, which makes the same tractor construc- tion suitable for all forms of vehicles ; the body may be high or low as desired, and the tractor can be applied to any existing horse-drawn vehicle. The general appearance of the A. & B. tractor applied to an Amoskeag Fire Engine is clearly shown at Fig. 269c. It is claimed that the 40 H. P. tractor with a "first size fire engine" can be speeded to a maximum of twenty-five miles per hour, which is about four times as fast as the same engine can be drawn with a three-horse hitch for any distance, that it will climb a 15% grade at three to five miles per hour, and that it has sufficient reserve power to start from a standstill and maneuver on that incline. It will climb a twelve-inch curbstone or pull through sand until the axle is buried. The Modern Gasoline Automobile 511 Corr\bir\ed. Directive Tractive Member Fig. 269d. Principal Parts of Hoadley System Tractor. A Power Plant and Generator Assembly. B The Combined Driving and Steering Axle Show- ing Method of Supporting Wheel Drive Motors. So sensitive is the control that the massive machine may be moved an inch or two at a time by the driver standing on the ground and controlling the speed lever. This tractor is made in four sizes, as follows : 22 H. P., suited for 512 The Modern Gasoline Automobile vehicles of 1 tons capacity ; 30 H. P., adapted to vehicles up to 2% tons capacity; 40 H. P., suited for 5 tons, and 60 H. P., for vehicles up to 7 tons. The power plant, which is clearly outlined at A, Fig. 2Q9d, con- sists of a four-cylinder L head gasoline motor with cylinders cast in pairs, which drives an electric generator coupled directly to the motor flywheel. This generator supplies current to operate the driving motors, which are located at each front wheel. Each motor, with the entire driving gearing, is combined with the combination tractive and directive member in a unit structure which swings on pivots for the purpose of steering. The wheels are connected and controlled by the usual form of handwheel and reduction gearing and by drag link and tiebar, as in the conventional front axle. The electric generator is connected directly to the wheel motors through a simple form of three-point control switch, there being no other electric intermediate member, except plain simple wiring. The power and speed are controlled chiefly by controlling the power and speed of the gasoline motor by the usual spark and throttle levers. The controller offers two forward speeds and a reverse, and by this added control the power and speed of the vehicle may be varied to suit conditions. With this electric drive combination, ideal control is obtained. Both speed and power are under instant command, and one can obtain any variations from zero to the maximum point with- out the various steps that are unavoidable where a clutch and change speed gears are part of the transmission mechanism. The illustration at B, Fig. 269d, shows a completely assembled tractor axle with wheels and driving motors in place. At Fig. 269e one will see the various details of the combined motor and wheel assembly at A, the appearance of the motor with the wheel and one end of the casing removed is depicted at C, and the wheel with internal spur driving gear in place is clearly shown at B. These views give excellent ideas of the application of the various parts of the power plant, the axle with the wheel driving motors and the various members comprising the axle assembly. The axle is of particularly stiff and rigid design, as the depth and bracing near the pivot ends permit of obtaining great strength without the use of a large mass of metal. The mo- tors, which are of the enclosed type, as shown at Fig. 269e, are built The Modern Gasoline Automobile 513 514 The Modern Gasoline Automobile into the steering knuckles, so that the motor, knuckle and spindle are practically an integral structure. As the combined driving and steering wheel forms a substantial unit, the torque reaction on the wheels is sustained by the pivots of the steering knuckle and the exceptionally strong front axle. The weight of the motor on one side of the pivot is said to closely balance the weight of the wheel on the other side, and it is advanced that this method of sustaining the weight minimizes the evil effects due to impact stresses found in construction where the motor had a pronounced overhang in rela- tion to the wheel. This feature proved to be a serious drawback in the early attempts that were made to employ an electric motor drive directly attached to members that could be moved for steering. The wheel is driven by spur pinions which engage with the large internal gear fastened to the wheel spokes. To anyone who has had experience in applying electric power to heavy vehicle drive, it is apparent that it is not easy to design a mechanically efficient method of drive between the motor and the driving wheels. An electric motor must run up to a certain speed in order to obtain the proper amount of power without using ex- tremely large motors and also to obtain the proper degree of effi- ciency. The driving wheels of heavy vehicles must turn at a rela- tively slow rate to correspond to the speed of the vehicle, and as large wheels are generally used on fire apparatus, this necessitates having a large ratio of speed reduction from electric motors to wheels which might be obtained by a two-step or three-step reduction. The two- step reduction is much the simplest, and is also the most efficient because less power is lost in friction of gearing. By referring to the illustration which the electric motor used for power, it will be seen that the method of power application is based on a clear under- standing of correct mechanical principles. Instead of taking the drive from but one end of the motor armature, as is common practice in most electric vehicles, the driving strains on the motor armature and the loads on the bearings due to driving torque are equalized by taking the power from each end of the armature shaft. A bevel pinion is securely attached by means of a taper fit and key at each end of the armature shaft and the driving pinions are retained firmly in place by the clamping nuts provided for that purpose. The armature The Modern Gasoline Automobile 515 516 The Modern Gasoline Automobile shaft is mounted on ball bearings which provide maximum effi- ciency, owing to. the practical elimination of bearing friction. At each end of the motor casings a cross shaft is placed which is right angles to the armature shaft. These shafts have the spur driv- ing pinions (which engage with the large internal gears of tl wheels) formed integral and are driven from the motor armatui shaft by bevel gears securely fastened to the shaft and meshing witl the bevel drive pinions. The wheel pinion drive shafts are mount* on roller bearings of the taper form which are provided with adjus ments by which they may always be kept in proper alignment. The use of the taper roller bearings mounted in the manner indicated permits of keeping the shaft from end movement, and also makes it possible to resist the end thrust on the gears, due to the angularity of the teeth. While there would be a certain amount of end thrust pres- ent on the armature shaft of the motor if the drive was taken from only one end, the use of the two bevel pinions and the method of mounting make it possible for the end thrust of one pinion to bal- ance that of the member on the other end of the shaft. The traction member is driven by the spur pinions, which are placed at opposite sides of the large internal gear, and thus the power delivered by the electric motor is applied to the wheel at very effective points or near the contact point of traction member and the ground. By the use of the two pinions at opposite sides of the large rack or internal gear, an absolutely balanced drive is obtained at the wheel as well as at the motor armature. The electric motors are designed so they will operate at a 300% overload with absolute safety. The Couple-Gear Four- Wheel Drive System. The Couple-Gear system is another method of utilizing electricity as a means of speed changing and power transmission with a gasoline engine as. a prime mover that supplies electrical energy by driving a dynamo attached directly to the crankshaft. The general arrangement of parts of the power plant is depicted at Fig. 269/. The gasoline engine and the dynamo it drives are attached to a subframe member, so the power plant complete is a unit that may be readily installed on the main frame of the chassis. The distinctive feature of the Couple- Gear system is the method of mounting the wheel driving motors between the two members comprising the wheel. One motor is The Modern Gasoline Automobile 517 518 The Modern Gasoline Automobile Fig. 269h. Front View of Couple-Gear Wheel with Tire and Rim Removed to Show Method of Driving by Bevel Pinions and Racks. attached inside of each driving wheel, as shown at Fig. 269g. The motor frame is attached to a carrier member integral with the wheel spindle and drives the wheel through two beveled pinions at the ends of the armature shaft, one of which meshes with a bevel drive The Modern Gasoline Automobile 519 rack at one side of the wheel, while the other pinion engages a rack of similar size on the other side of the wheel. At Fig. 26Sg one side of the wheel is taken off so the construction of the wheel-driving motor and the arrangement of the driving gearing may be readily ascertained. The illustration Fig. 269/i shows a front view of the wheel with the rim removed to show the manner in which bevel pinion A drives bevel rack A, while the bevel pinion B is in mesh with the bevel rack B. The wheel spindle which projects from one side of the wheel fits a corresponding taper hole in a steering knuckle of suitable form, which makes it possible to incline the wheel as desired for steering without interrupting the continuity of the drive. The couple-gear system is sold in two- and four-wheel units, and where four wheels are used, all four members combine directive and tractive functions. The two-wheel type is in the nature of a tractor that is intended to be attached to the front portion of the frame of any heavy vehicle, such as fire apparatus. CHAPTER IX The Chassis and Its Components Frame Design and Construction Typical Methods of Spring Suspension Outlined Function of Steering Gears Steering Gear Forms Defined Front Axle Types Rear Axle and Driv- ing Means Power Transmission by Bevel and Worm Gearing Conven- tional Braking Systems Application of Front Wheel Brakes. THE average motor-car chassis is composed of a number of parts distinct from the power plant and transmission groups. The im- portant components are the axles, the steering system, the method of power transmission to the wheels, the design of the frame, and the spring suspension means. The frame forms a connecting link be- tween the motive power and the parts which serve to support the body and machinery. Formerly frames were made in many different styles and a number of different materials were utilized in their con- struction. At the present time the practice has crystallized to a point where certain construction has been definitely accepted as the best and this is generally followed in practically all forms of motor cars. Frame Design and Construction. The usual arrangement of the components of typical chassis forms is outlined at Fig. 270. The power plant and its accessory groups as well as the change-speed gear- ing have been previously described, and the chassis forms outlined are presented to show the two distinct systems of chassis construction generally followed. The arrangement of parts depicted has become accepted as best practice and practically all motor cars are about the same in general design. The arrangement of the chassis shown at A is the conventional one, and in this the frame which carries the operating parts is mounted above the axle. In the form shown at B an underslung frame construction is used. In this case the springs are coupled to the axles but the frame members are suspended from the springs instead of being placed above them as shown at A. The advantages claimed for the underslung construction are that it is more stable because the weight is carried nearer the ground and 520 Spring otor Steeri:: Front Kg. 270. Conventional Gasoline Automobile Chassis Forms. A Type in whi* in which Frame is ' it. ring Wheel Change Speed Levers Gearbox Frame Rear Spring Drive Shaft Rear Spring ie is Mounted Over Axles, the Usual Construction. B Underslung Chassis, .ed Beneath Axles. The Modern Gasoline Automobile 521 the car is more easy riding and will sway less at high speeds than those types where the frame is carried above the axle. The advantage of bringing the center of gravity close to the ground is clearly illus- trated at Fig. 271. At A the center of gravity of a heavy limousine car whk-li lias an underslung frame is at a point just above the axle, Fig. 271. Advantage of Low Weight Placing and Carrying Center of Gravity Near the Ground. A Low Center of Gravity Makes for Stability. B High Center of Gravity Unsafe. and if the car tilts over a marked degree, a line drawn from the center of gravity will fall within the area of the base of support as repre- sented by the rectangle, the corners of which are at the contact points of the wheels and the ground. The center of gravity of any body is *he theoretical point around which the weight may be said to be f.'-nly distributed, and whenever a line drawn from the center of gnivitv falls within the base line of any body or mass it is in stable equilibrium. In the case outlined at B the center of gravity is carried higher because the frame is mounted above the axle and conditions may obtain where the line drawn from the center of gravity will fall out- side of the base line and the car tip over. While the conditions shown an- somewhat exaggerated they will serve to make the comparison clear and will enable the nontechnical reader to understand the 522 The Modern Gasoline Automobile advantage of carrying the weight of the machinery as near the ground as possible to secure steadiness at high speeds. The factor of carrying the weight low is much more important in the case of cars which are to be equipped with large closed bodies of the limousine type. It must not be inferred that it is not possible to carry the weight low with the form of frame construction denned at Fig. 270, A, as in the case illustrated the machine weight is car- ried practically as near to the ground as it is when the underslung frame shown at B is employed. The difference in center of gravity of the whole machine is evident only when the body is fitted and it will be carried considerably lower with the underslung frame than in the one where the frame members are mounted above the axles. Materials Employed in Frame Construction. The first motor cars were based somewhat on experience obtained in bicycle construction and had frames made of steel tubing. This material was not as suitable for motor-car frames as it had been for the lighter two- wheeled vehicles because the multiplicity of brazed joints necessary made the frame quite a costly proposition. Then again the round section of the tubing did not offer as easy means of attaching the engine, and transmission units as do those frames which are com- posed of members having a rectangular section. Tubing is used only in subframe work, at the present time notably in the Flanders light four-cylinder car and some of the Lozier models. Following the use of the tubing, automobile builders used angle iron and other structural shapes available on the open market. Other makers used wooden frame members, but at the present time one rarely finds either structural iron or wood used in pleasure cars, though both of these materials have been applied to some extent in motor-truck construction. Some makers, notably the Franklin Com-< pany, employ frames which are made of laminations of specially seasoned and strong wood. The majority of manufacturers, however, favor the use of pressed steel forms which are not only light and 3 strong but which have a degree of flexibility which is very desirable and which is not easily obtained with the various structural shapes in iron. Frames may be divided into five main classes, as follows: Those in which wood only is used, forms utilizing pressed steel construction, The Modern Gasoline Automobile 523 types employing steel tubes, frames built up of iron structural shapes, and combination frames where two or more different methods of construction may be combined. For instance, it is possible to reen- force a wooden frame side member with a strip of steel or iron, or at the other hand some makers sometimes fill the channel of a pressed steel frame with wood to strengthen it. Each of these main divi- sions might be again divided. For instance, wood frames may be made of a solid strip or beam or may be composed of vertical or horizontal laminations. Pressed steel may be made into channels, angles, or modifications of these, while frames composed of tubing may be square, rectangular, or round section. The various structural shapes may be utilized in the form of plate, angles, T rail sections, and I beams. A typical pressed steel frame is shown at Fig. 272 and this is the type which is very generally employed. The frame-side members are Running Board Irons Fig. 272. Conventional Form of Pressed Steel Automobile Frame with Cambered Side Members. two pressed steel forms cambered at the front ends and joined to- gether by a series of three cross braces. The front one serves as a radiator support, that in the center provides anchorage for the torque tube of the axle, while the rear cross member projects on either side of the frame and provides a point of anchorage for the rear support- ing springs. The object of cambering the frame members in front is to provide a greater angle of operation for the front wheels and to 524 The Modern Gasoline Automobile permit turning on curves of smaller radius than would be possible if the frame members were straight and movement of the wheels limited thereby. In some frame constructions where semi-elliptic springs are used at the rear end as well as the front of the car, the frame is some- times raised at a point directly over the axle, as shown at Fig. 273, A. Often a double drop is provided in the frame side, as shown at Fig. 273, B. In this construction the frame side is straight to a point Fig. 273. Frame Forms Having Raised Side Members. A Frame Side Raised Over Axle. B Framework with Drop Side Member. about half the length of the chassis, then it drops and when it reaches the axle it raises again to allow for movement of the axle. The ob- ject of dropping the frame is to provide a slightly lower floor board placing than would be possible if the body was carried at one level. The rear upsweep, by raising the back end of the frame, enables the axle to be carried in a position that will permit a nearly straight line drive. It will also bring the running board of the car closer to the ground, which makes the body more accessible, and it lowers the center of gravity as well. At the same time sufficient space is provided between the raised rear end and the axle to permit of using springs which will be adequate to support the weight of the mechan- ism and body and yet permit these to have a considerable radius of movement and make for much easier riding. The Modern Gasoline Automobile 525 By bringing the lowest level at a point between the front and rear it is possible to carry the body low and at the same time support the engine and transmission at a sufficient height above the ground to insure ample clearance between the bottom of the motor and the surface of the roadway. The advantage of the pressed steel frame over the other forms is that it is a very easy type to make and very cheap after the forming dies have been made. It lends itself read- ily to designs where it would not be possible to use the wood frame because of the serious diminution of strength if wood is bent in any way that will distort the grain. Suspension of Motor Vehicles. One of the most important prob- lems in connection with chassis designing is that of the supporting members which join the frame to the axles and which are depended upon to absorb much of the shock and jar incidental to motor-car operation. The importance of the springs and the part they play iii promoting the comfort of the passengers, the durability of the machinery, and economical application of power are but little appre- ciated by the majority of motorists. One point that has made it difficult for the automobile designer to evolve spring types which were entirely satisfactory was the paucity of data regarding spring action of high-speed vehicles. The forms of springs that were used on wagons and carriages were studied, but when these were applied to motor cars which had much greater speed than the simpler vehicles the problem assumed a new aspect. While the horse-drawn vehicle operates on rough roads the speeds are comparatively low, and the roughness of the roads is not such an important factor as it is in the design of automobile springs. Railway cars were studied in the hope of finding a solution. Here the conditions are reversed, and while they operate at high speeds they run on comparatively level- steel rails and the conditions of operation make the problem of spring suspension one that is not difficult. One point greatly in favor of the motor car is that for the most part these are mounted on pneumatic- or air-filled tires and these have valuable cushioning properties in themselves and are of material value in solving the problem of spring suspension. It is very difficult to combine both strength and resiliency in springs, as if these are made light and flexible they are not likely to be strong. A vehicle 526 The Modern Gasoline Automobile that might be very easy riding on good roads would have too much spring movement if the springs were lacking in strength Avhen oper- ated on rougher road beds. At the other hand, if springs are made stiff to take care of severe conditions they will be hard acting when used on smooth roads. Another factor which makes it difficult to select the proper springs is the variation in weight carried. When an engineer de- signs a five-passenger touring car he must provide springs of adequate strength to take care of the car when it carries its full complement. If but two passengers are carried the car will be stiffer riding than when the weight of five persons must be supported. An added point that makes it difficult to select springs for auto- mobile suspension except by experiment is that the propelling force forms part of the conveyance and power must be transmitted from the source mounted on the frame to the wheels resting on the ground. As the frame is suspended on more or less flexible members and moves in various directions, the degree of movement must be limited so there will be no excessive strain imposed on the transmission mechanism. Ease of riding is largely determined by the radius of movement or upward throw of the body, and the object with any kind of spring suspension is to reduce the up and down movement to as low a point as possible without actually retarding the vibrations. Eapid vibration of the springs will cause discomfort and will affect to a considerable degree various parts of the chassis which connect the frame to the axle, such as radius rods, steering connections, torque members, and driving means. Of the various forms of springs it is possible to use the laminated leaf spring is that which has been generally applied on automo- biles just as its use has become universal on horse-drawn conveyances. The great value of the laminated leaf spring is that its capacity can be varied by changing the number of plates or leaves used and almost any desired degree of resiliency can be obtained by varying the thickness, grade of material, and width of the plates of which the spring is composed. Design of Leaf Springs. The leaf springs used for the suspension of road vehicles consist of several layers of steel plates so shaped that when laid together they form superimposed arcs of as many The Modern Gasoline Automobile 527 circles as there are leaves. The spring effect is obtained by the elas- ticity of the metal used which is increased in value by a process of ]ir;it tn-iit iii(.'iit known as tempering. The leaves are usually gradu- j ated in thickness, being thicker at the center and tapering from the center to the ends. The reason for following a common line or arc when a spring is composed of more than one leaf is that as all of the leaves are de- tlccted ;il omr by the load and as the tendency is to straighten out the curved member, they should slide upon one another when alter- ing their shape in such a manner that they will always be in contact with the neighboring leaf at all points. If the curvature of the leaves differed appreciably' the tendency of the plates under load would be to straighten out and separate and the load would only be carried on those members which were in contact at all points. This would be undesirable because it would cause a loss of spring action i and would also result in frequent breakage. Fig. 274. Springs Usually Employed for Supporting Motor-Car Frames and Horse-Drawn Vehicle Bodies. The common forms of springs which have been used for supporting motor-car frames are shown at Fig. 274. That at A is a full elliptic type and consists of two semi-elliptic spring members hinged together at their ends. The semi-elliptic type, which is half of a full elliptic 528 The Modern Gasoline Automobile spring, is shown at B. The spring illustrated at C is a three quarter elliptic form used for suspending the front end of some types of cars. The scroll elliptic spring depicted at D is a modification of the full type, but it is somewhat more flexible because the lower member is fastened to the upper by means of shackles which permit more movement than the rigid bolt and eye connecting the members of form A. The side spring depicted at E is a modification of the side spring commonly fitted to Concord buggies, and while it has received some application on earlier forms of automobiles it is not used at the present time. The form shown at F is a three quarter scroll elliptic member which is very widely used at the present time for rear suspension of motor cars, especially in those chassis having upswept rear ends. The application of the spring forms previously considered to the front end of motor-car frames is outlined at Fig. 275. The view* at Fig. 275. Spring Suspension Means for Front Ends of Motor-Car Frames. A Semi-Elliptic. B Full Elliptic of Franklin Car. C Single Cross Spring of Ford Design. Fig. 276 show various spring combinations used for rear-end suspen- sion. The common method of supporting the front end is shown at Fig. 275, A, and is used on the greater proportion of motor cars. Of the rear suspensions that shown at Fig. 276, D, is popular on heavy The Modern Gasoline Automobile 529 vehicles, while the full elliptic depicted at C and the three quarter scroll elliptic outlined at E also receive general application. The semi-elliptic spring is not as easy riding as the other forms unless it is made very long and composed of but a few leaves. The various full Fig. 276. Spring Suspensions for Rear Ends of Motor-Car Chassis. A Sin- gle Elliptic Cross Spring of Ford Cars. B Semi-elliptic Side Member. C Rear Support by Full Elliptic Spring. D Platform Spring Con- struction. E Three Quarter Elliptic Application. and three quarter elliptic forms are much more flexible than a semi- elliptic of the same length and are more generally used for rear sus- pension where a greater degree of movement is desirable than at the front end. When an automobih chassis is suspended on springs the frame will move in various directions. There is a certain amount of for- ward and backward end throw, an element of side sway and the up and down motion caused by the deflection and recoil of the spring. The object of an efficient spring suspension should be to minimize the end throw and side sway as much as possible and yet preserve the freedom of movement of the spring. It is for this reason that the semi-elliptic form is so popular for front suspension. It is a stiffer member than the others and is better adapted to carry the weight of the power plant without side away and to keep the front axle in that 530 The Modern Gasoline Automobile relation with the steering mechanism necessary to secure the best action. In general the methods of suspension employed by automobile de- signers follow closely those that have been used for a number of years by manufacturers of horse-drawn vehicles. When elliptic or semi- elliptic springs of the ordinary description are used one will see that in most light horse-drawn carriages but two are employed, one being placed over each axle and parallel with it. In motor cars one seldom finds a single spring used for suspension at both ends. Usually if one spring is placed in this manner over one of the axles there are generally two arranged in the conventional manner over the other axle to provide a three-point support. A notable exception is the: Ford car which employs a single cross spring at each end of the frame.- When only one spring is used in this manner radius or distance rods are required to maintain a fixed distance between the axle and the frame at the front axle., and more substantial members of the same character which will have to take the driving torque effect as well as the braking stresses will be required for the rear end. This makes two sets of radius rods necessary on each car. Most automobile de- signers favor the use of two semi-elliptic springs at the front end be- cause with these there will be no need of using radius rods, as the springs are capable of maintaining the proper relation between the axle and the frame as well as resist the pushing or pulling effect due to traction, which would otherwise have to be taken by radius rods. With practically all forms of rear suspension, especially in those which utilize the elliptical forms of springs, the inevitable forward throw makes the use of radius rods imperative. It is necessary that the proper distance be maintained between the motor mounted on the frame and the rear axle where the power is applied to the wheels. The amount of play permissible is governed entirely by the char- acter of the driving system and with some forms there can be more latitude of movement than possible with others. In nearly all cases, however, it is essential that very nearly a fixed distance be maintained, or there will be injurious stresses on the sprockets, chains, universal joints, or gears with attendant loss of power. A factor that has become very important is the selection of suitable alloy steels for the construction of the springs. The rapid develop- The Modern Gasoline Automobile 531 ment of high-powered automobiles which are capable of extremely high speeds had made the development of more resisting and elastic steels imperative, as the open hearth metal of standard analysis used in the manufacture of carriage springs would not make satisfactory supporting members under the severe conditions imposed by the mod- ern automobile. For this reason, various alloy steels, such as vana- dium steel and mixtures of iron, carbon, chromium, and 'nickel have been developed especially for fabrication into springs. Among the other functions of springs they reduce to a certain extent the traction resistance. When the driving wheels meet ob- stacles the shock produced depends upon the inertia of the axle and that of the wheel which comes into contact with the impeding sub- stance plus the resistance of the springs, which factor varies with the elasticity and design. If the springs are not sufficiently resilient the shock will lift a portion of the car as well as the wheel and axle, whereas if elastic members are employed only the axle and spring will be affected. It is patent that more power is required to sur- mount obstacles when stiff springs are employed, and part of the power delivered by the engine which might be used to better advan- tage in propelling the car is absorbed in overcoming the obstacle. The attachment of springs to the frame and axle is a phase of the suspension problem that is important. The front end of the front springs is usually pivoted directly to the frame in spring horns forming a portion of the frame-side member. The free end of the spring is connected to the frame by a shackle to allow the necessary motion. The rear springs are usually attached to the frame in a different manner than the front member because to secure maximum efficiency the rear springs should be called upon only to support the load, and they should be relieved of all traction and torsion forces by suitable torque members or radius rods. If springs of the semi-elliptic type are used it is advisable to double-shackle them, whereas full elliptic forms should be attached to the frame by some sort of a swivel joint in order to allow the necessary motion. The method of fastening the springs to the axle is by means of clips very similar to those that are used in carriage construction, but they are usually heavier and of better material. The spring rests upon a piece of leather or wood placed between it and the supporting 532 The Modern Gasoline Automobile pad on the axle and this material is usually curved enough to con- form with the arc of curvature of the spring. This cushion is interposed between the two elements for two reasons,, one of these being to avoid the strain which would be imposed upon the spring if attempt was made to attach it directly to the flat or slightly curved spring pad on the axle. The other reason is that the cushion provides a more rigid fastening because there is a certain amount of friction Spring Friction Washers Fig. 277. Unconventional Spring Suspensions. A Double Semi-Elliptic Used on Winton Cars. B Coil Spring and Shock Absorber Combination of Liberty-Brush Runabouts. between the spring and the wood or leather piece which prevents slipping of the fastening. Authorities agree that springs should never be fastened by means of bolts passing through the leaves, as this will make a weak place in the spring which may break if stressed unduly at this point. Some manufacturers use distinctive forms of springs developed The Modern Gasoline Automobile 533 solely for use on their product. The spring shown at Fig. 277, A, is that employed on some models of the Winton cars and is a com- pound form which consists of two parts which are virtually separate and distinct semi-elliptic springs. These are shackled up in such a manner that when the loads are light but one portion of the spring is used, though when the car is fully loaded both sections of the spring are brought in action. It is claimed that this method of spring con- struction permits easy riding under all varying conditions of load or road surface, as the strength or resiliency of the .springs is governed entirely by the demands made upon it. When conditions of operation are severe the spring strength is augmented proportionately, and it becomes more resilient as the load is decreased. The method of suspension employed on the Brush runabout is outlined at Fig. 277, B. This is distinctive inasmuch as it is the only motor vehicle produced in large quantities or in a commercial way which employs helical coil springs under tension to support the load. It will be noted that a combined shock-absorbing and radius- rod device is essential. Ths method, while extremely efficient, ap- pears rather unconventional and is regarded as a " freak " design by most engineers. The construction is clearly outlined in the illustra- tion and four such springs are employed, one at each corner of the frame. How Automobiles are Steered. The problem of steering the motor ear is a somewhat different one than that of directing a horse-drawn vehicle because in the animal-drawn conveyance the shafts which are attached to the front axle are used to turn the vehicle as well as to pull it along. The front axle is usually pivoted at a central point and turns on a fifth- wheel arrangement, as shown at Fig. 278, A. When it is desired to turn in either direction the animal is guided by the reins and the axle is turned at an angle to the body sufficient to allow the vehicle to describe a curve as shown by the dotted lines. When turning sharply or in a narrow thoroughfare the construction is usually such that the front wheels may swing under the carriage body in such a way that the front axle may be parallel with the body side members or at right angles to the rear axle under extreme condi- tions. The stability of the carriage would be very poor if it was not for the bracing effect derived from the horses' weight between the shafts. 534 The Modern Gasoline Automobile In most motor vehicles the propulsive force is applied to the rear wheels and the structure is pushed from behind instead of being pulled, as is the case with a horse-drawn conveyance. Obviously, it would not be practical to turn the entire axle under the car because if it described a too acute angle when the car was driven at high Fig. 278. Methods of Steering Vehicles Outlined. A Horse-Drawn Wagon Directed by Swinging Axle. B Motor Car Steered by Movable Wheels on Fixed Axle. speed it would be extremely difficult to control the vehicle. This was very ingeniously -overcome by an engineer named Ackerman, who de- vised the pivoted axle which is commonly accepted as the proper method of steering automobiles. This consisted of a fixed axle member, as shown at Fig. 278, B, The Modern Gasoline Automobile 535 which was attached to a frame by suitable springs or other means in such a way that it could only move in a vertical direction under the influence of road irregularity. The wheels are mounted on spindles carried in a yoke at each end of the axle, and when it is desired to turn an automobile only the wheels are turned instead of moving the entire axle assembly as is the case in a horse-drawn vehicle. In order to actuate the steering knuckles, suitable mechanism that will lie easily operated must be placed convenient to the driver. The earlier forms of automobiles were provided with forms of tillers very similar to those employed in controlling boats, but while these simple levers gave a certain degree of satisfaction on light cars operated at slow speeds, the development of the higher-speed vehicles made neces- sary more easily handled and positive forms of steering gears. The disadvantages of the tiller are that it may be whipped out of the operator's hands by road irregularities, and it is very tiresome to hold because of the continual vibration. With the modern forms of wheel-steering devices the hands are always in an easy position, the wheels may be readily operated and because of the elimination of vibration by the feature of irreversibility provided by most steering gears of conventional construction, no road shock can loosen the grip of the driver, nor is he fatigued by con- tinued movement of the wheel. Steering gears are made in a variety of forms and all types have their adherents. The accepted construction is clearly illustrated at Fig. 279, A. In this the steering wheel is attached to a rod which carries a worm at its lower end. This worm meshes with a worm gear to which a steering arm is attached, and a rotary movement of the hand wheel will produce a reciprocating movement of the steer- ing arm at the lower end of the steering column. The steering arm is coupled to one of the steering knuckles of the front axle by a connecting link and the movement imparted to the one steering knuckle is translated to the other one by means of the tiebar which joins them. The form of steering gear outlined at B is a simpler one, but it does not incorporate the good features of the worm-gear type. It consists of a spur pinion at the end of the steering post which meshes with the spur-gear rack actuated when the hand wheel is turned in 536 The Modern Gasoline Automobile such a way that the rotary motion of the wheel is transformed to a reciprocating movement of the rack. The rack is directly attached to one of the steering knuckles by a drag link coupled to an extension from one of the steering arms. In a modification of this type a bevel gear is used at the lower end of the steering post and a bevel-gear sector is utilized to actuate the drag link. The principle of action is Fig. 279. How Front Wheels of Motor Cars are Moved. A Conventional Worm-Gear Reduction Steering Arrangement. B Simple Rack and Pinion System Used on Light Cars. the same as in the form described, however, and while either of these forms may be applied to light cars and make for ready control be- cause they are quick acting they are not desirable on heavy vehicles because they do not provide the feature of irreversibility which is necessary. The factor of irreversibility in steering gearing is one that was formerly a point of contention among authorities on automobile con- struction. It was argued that the irreversible form does not provide that quick action which is considered necessary to secure prompt con- trol of the car. At the other hand, the strictly reversible gear such as the spur rack and pinion, which is especially quick acting, will tire the operator whenever the car is operated on rough roads, as every inequality of the road service will tend to produce a corresponding The Modern Gasoline Automobile 537 side motion of the wheel which will mean considerable play at the rim of the steering wheel. Some engineers who contended that the worm and sector gear wore liable to wear devised combination forms in which a screw and Throttle Lever \ Steering Post Beuel Gears Fig. 280. Unconventional Steering Gear Employing Threaded Steering Post and Movable Nut with Rack to Engage Sector on Steering Ann Shaft. mil principle was combined with a rack and sector gear, the object (icing to provide a largely increased bearing surface on the threads and gear teeth and in this manner reduce wear. A gear of this type is shown at Fig. 280. The nut or internally 538 The Modern Gasoline Automobile threaded member is held from turning by various methods, such as flattening one side and having this in contact with the walls of the casing, by the use of keys or dowel pins, or merely by the pressure of the rack and sector shown in illustrations. The advantage of this form of steering gear is that it is wholly irreversible and at the same time a minimum of effort is needed on the part of the driver to properly control a very heavy car. The amount of movement of the nut, up and down, is regulated by the pitch and angle of the thread and as the nut is provided with a spur rack its rectilinear motion is transformed into an oscillating movement of the steering arm at- tached to the spur-gear sector. The worm and segment type of steering gear is without doubt the most popular with automobile manufacturers of this country and Europe. It is simple, compact, and positive in action. The steering post carries a worm at its lower end, as shown at Fig. 281. This in turn meshes with a suitable worm wheel or segment attached to the steering arm. The worm when turned will produce a fore and aft movement of the steering arm which in turn is transmitted to the wheels by suitable leverage. This type of gear must be maintained in perfect adjustment and be well lubricated at all times. The great- est defect is the wear that will exist between the worm and worm- gear teeth, and the difficulty of devising any really practical method of taking up the play. The constant oscillations of the vehicle wheels will cause the sector teeth and worm thread to wear at one place, which corresponds to the straightahead position of the gear. This may be taken up in most forms by the use of eccentric bush- ings in which the sector shaft is mounted, these being moved in such a way that the sector teeth are brought into closer engagement with the- thread of the worm. This method is not desirable because if the eccentric bushings are turned enough to take up the lost motion existing between the teeth, the change in worm-gear position would cause binding between those portions which had not worn as much and which were brought into play only when it was desired to turn the wheels to nearly the extreme angular position. The preferred method is that outlined at Fig. 281. In this a full Avorm wheel is used instead of a sector and when wear occurs at one point the worm wheel is removed, the hand wheel and worm are given a complete turn, The Modern Gasoline Automobile 539 and the worm wheel is replaced in such a way that a new set of teeth i on both worm and worm gear will be in mesh. With all conventional forms of steering gears the object has been ; to get a complete sweep of the front wheels, that is to turn them from one extreme position to the other with about one and one half - Spark Lever Rod 'Throttle Control Tube -Sector Anchoratre Spark Lever Steering Post / Spark Lever Gear Throttle Lever Gear teeringr Arm Fig. 281. Construction of Worm and Worm-Gear Reduction Gearing for Steering Purposes. turns of the hand wheel. Anything slower than this will be so tardy of action that it will be difficult to steer the car properly and quickly at anything but low speed. On some heavy commercial vehicles, how- ever, it is necessary to provide lower reduction, and two or two and a half turns of the steering wheel are sometimes necessary to produce the proper degree of movement of the front wheels. This is not a point that can be seriously objected to when one considers the low speed of the conventional motor truck. On high-speed cars some authorities claim that one turn of the wheel to produce a full move- ment of the steering wheel is entirely satisfactory, as it permits han- dling the car with minimum lag and makes it quick to respond to the control gearing at all speeds. It is common practice on most motor cars to combine the motor- 540 The Modern Gasoline Automobile controlling levers with the steering gear in such a way that the speed of the motor may be varied as desired without the operator removing his hands from the steering wheel. The manner in which this may Steering Wheel Spokes Steering Wheel Rim ark Lever Throttle Lever Ball Ball Joint DragLink Bearing Fig. 282. Typical Steering Post Assembly Showing Hand Wheel and Motor Controlling Levers. Sectional View of Worm and Worm Wheel and Steering Arm Connecting Member. be accomplished is clearly shown in the steering-gear design depicted at Fig. 282. In this the steering wheel is attached to a tubular The Modern Gasoline Automobile 5-U :eering post, through the center of which a rod mounted inside of vo concentric tubes is passed. The outer tube is anchored at the >tt oin end of the steering-gear casing and carries the sector on which ic spark and throttle levers move. The short lever is attached to ic rod passing through the center of the assembly, and this in turn ituates by means of bevel gearing an auxiliary control shaft mounted i front of the steering-gear assembly. The long lever is attached to ic tube which surrounds the central rod, and this member also carries gear at its lower end which engages a tube surrounding the spark- ^ver control shaft at the front of the steering gear. The spark e resisted. The general construction of these steering knuckles ;m<] the mode of application of the bearings on which the hubs re- volve are so clearly shown that further description is not necessary. Typical Power Transmission Systems. One of the factors making for motor-car efficiency is the system of transmission employed by which the power delivered by the engine is transmitted to the rear 544 The Modern Gasoline Automobile wheels, and the most efficient system is obviously that which will deliver the power to the rear wheels with minimum loss. The com- mon methods of power transmission are outlined at Fig. 285. That at A is the system formerly used on many light cars which derived their power from a single-cylinder engine placed lengthwise in the chassis. The drive from the sprocket on the planetary gearset is by means of a chain to a sprocket on the differential gear of the rear axle. This was one of the most direct methods of transmission possible and was remarkably efficient as long as the chain was kept clean, properly oiled, and in correct adjustment. The efficiency of this arrangement was very high, and about ninety per cent of the en- gine power was delivered to the wheels on the direct drive and about seventy-five per cent when the planetary gearset was in operation. The system shown at B was formerly very popular on all classes of touring cars, but is seldom used at the present time except in heavy commercial vehicles. With this system the differential gear is carried adjacent to the gearset and driving shafts extend therefrom to sprockets at each side of the frame. The drive from the counter- shaft member is by means of driving chains to sprockets on each rear wheel. The wheels are mounted so they revolve on a stationary axle. It is believed that this construction is stronger than the live axle for heavy vehicles, and it is also used because it permits the designer to obtain a double reduction and very low ratios of speed, which make it very suitable for motor- truck service. The efficiency of this method of driving is lower than that in which either chains or gears are used alone, and even when the gearset is in the direct drive position or high-speed ratio there is a loss of twenty-five per cent in transmission, which gives a net efficiency of seventy-five per cent under most favorable conditions. When on the lower ratios, which demand the use of the change-speed gearing, the efficiency is reduced to about sixty per cent. Various forms of shaft-drive systems are popular at the present time and the two methods of employing shafts differ merely in detail. In the diagram shown at Fig. 285, C, two universal joints are em- ployed and a length of driving shaft. One of these joints is mounted at the end of the gear box on the power plant unit, while the other flexible member is attached to the differential housing. The drive Pig. 286. Methods of Power Transmission Employed by Motor Car Designers. A Single Chain Drive from Planetary Gearset to Live Rear Axle. B Side Chain System. C Drive by Exposed Shaft Having Two Uni- versal Joints. D Drive Shaft Enclosed in Torque Tube Needs but One Universal Joint. 545 546 The Modern Gasoline Automobile from the shaft to the wheels may be by bevel or worm gearing and when this system is employed it is necessary to use some form of radius rod member to keep the axle in proper relation with the frame. When the method depicted at D is employed but one universal joint is needed. The driving shaft is encased in a tubular member usually attached to the frame in such a manner that it serves as a radius member and permits the axle to move up and down under the influence of rough road surfaces, but does not permit end movement of the axle. The efficiency of the shaft-driving systems is very high compared to the double-chain drive and as all parts are always en- Emersrenoy Cover Fig. 286. Chassis of Knox Car, in which Straight-Line Driving Shaft is Utilized, which Permits Power Transmission with but Minimum Loss. closed and run in lubricant the efficiency may be conserved. While the power loss with a bevel-gear and shaft-driving system is apt to be a little higher than the single-chain method when both are new, deterioration is apt to be more rapid in the chain-driven cars. If care is taken to install the power plant so the propeller shaft will be on a straight line with the engine crank shaft, as depicted at Fig. 286, but fifteen per cent of the power will be lost in transmission. If the driving-shaft angle increases the efficiency will be lower. A safe rule for estimating this is given by some authorities as one per cent loss for each degree of shaft inclination. This power loss is due to fric- tion in the universal joints, as the amount of movement of the joint yokes on the cross or bearing pins increases with the angularity of the shaft. The universal joints will depreciate rapidly if there is too much movement and soon become noisy. The Modern Gasoline Automobile 547 I* T -o 1 I 548 The Modern Gasoline Automobile Pour- Wheel Drive and Steer System. Gasoline automobiles have been designed where the drive is through all four wheels which combine directive and tractive functions. A side elevation of the new Jeffery four-wheel drive motor truck with important parts depicted is clearly shown at Fig. 286a. In this the power is obtained by the regular Eambler power plant driving through a dry disc clutch to a change-speed gear of special construction mounted on the chassis frame about midway between the front and rear axles. One drive shaft extends from the front end to the front axle, while a similar member transmits power to the rear axle, which is a duplicate of that used at the front of the car. Drive Shafts to Axles Fig. 286b. Details of Special Gearset Used in Jeffery Four- Wheel Drive Truck. The Modern Gasoline Automobile 549 The special form of gear box necessary is outlined at Fig. 2866. In this the drive is through gearing at all speeds, there being no direct drive clutch, as is true of conventional gear sets. The trans- ini>sion provides four speeds forward and a reverse and in addition to the usual countershaft carried below the main shaft, a quill is mounted below this which carries a differential gear. From this differential two drive shafts provided with universal joints transmit the power to two auxiliary differentials located on the front and rear axles respectively. The differentials on the axles in turn drive the wheels and as the wheels are movable to steer the vehicle, as well as rotatable to drive it, it is apparent that the final drive shafts which transmit power to the wheels must have universal joints to compensate for wheel movement when set at an angle to direct the vehicle. One of the universal joints employed at the wheels is shown at Fig. 286r. The universal joint is a regular double yoke and cross type enclosed in a housing that protects it from the dirt and grit and which permits of considerable movement of the drive shaft without allowing the lubricant with which the universal joint is packed to escape. One end of the universal joint is attached to the drive shaft which runs to the differential on the axle, while the other yoke drives a spur pinion which is well supported by a taper roller bearing placed at each side. This spur drive pinion engages with an internal spur gear car- ried within the body of the wheel and applies the power near the wheel rim, thereby gaining the greatest driving leverage possible. The internal gear of the wheel and the pinion driving it are well housed to exclude grit and retain lubricant, and this housing at the same times serves as a brake drum. The wheels, one of which is shown at Fig. 286c, are interchange- able. The two drive axles w r i.th their universals are duplicates of each other and the three differential gears, consisting of that in the gear box and those on the axles, are all alike. The differential is a special AVayne type which differs from the common construction in that it automatically drives the wheel which has the greatest resist- ance and which has traction, and this feature, coupled with the use of four driving wheels, makes it possible to propel the truck if any one 550 The Modern Gasoline Automobile Spoke Steering Knuchle Bolt Solid Rubber Tire Fig. 286c. Sectional View of Wheel of Jeffery Truck Showing Method of Drive by Spur Gearing. of the four wheels has traction. It is claimed that while the truck has 120 inches wheel base, it will turn in a circle of twenty-two feet radius, which is accomplished by the four-wheel steering feature. There are four ample brakes, one on each wheel, and it is claimed that either set of two brakes is sufficient to hold the loaded truck on a 30% grade. The wheel revolves on taper roller bearings car- ried by the wheel spindle. The steering knuckle is a special form of the inverted Elliot type, and not only carries the wheel spindle, but the frame supporting the spur driving pinion as well. The loaded front axle is supported by a taper roller bearing at the lower end of the steering knuckle which makes it possible to turn the wheel with The Modern Gasoline Automobile Wheel reJto0fi>fir* > \ 551 Brake /internal Spur Gear Band/ Brake Drum Roller Fig. 286d. Details of the Jeffery Four-Wheel Drive Construction. A Axle End with Wheel Removed to Show Driving Gear. B Arrangement of Differential Case and Universal Joints on Drive Axle. 552 The Modern Gasoline Automobile minimum exertion on the part of the operator. When the wheel is moved by the steering knuckle the frame carr} r ing the spur drive pinion turns as well, but owing to the universal joint the drive is not interrupted and the wheels are all driven regardless of whether they are in a straight-ahead position or at an angle to steer the car. Other vehicles have been evolved and applied as tractors for fire department service where the drive is through the front wheels only, these mem- bers being very similar in construction to the form described. Radiator Steering / Wheel Power Plant Tractive and Directive Member Fig. 286e. Sectional View of Front Portion of English Motor Truck Chassis Employing Front Wheel Drive. Front Wheel Drive System. In some forms of vehicles the front wheels only are employed for driving even when the power is derived from a gasoline engine and transmitted to the wheels by some form The Modern Gasoline Automobile 553 Fig. 286f. Plan View of Front Wheel Drive Truck Showing Location of Power Plant, Countershaft Assembly and other Parts. of mechanical transmission instead of by a more flexible medium, such as electric current. The front end of a truck of this nature is clearly outlined at Fig. 2S67, and this is really a tractor that becomes an integral part of the vehicle to which it is joined. The power is derived from the conventional form of four-cylinder water-cooled motor which delivers its power to a gear set combined with a counter- 554 The Modern Gasoline Automobile shaft which is shown in the plan view at Fig. 286L As far as the location of the power plant and gearset goes and the method of coupling these members together, the construction follows conventional practice. The difference is that instead of the drive being from the sprockets at the end of the countershaft member to the rear wheels, the chains go to the front end of the car and drive the front wheels, which form part of an axle of peculiar design. One end of the distinctive axle construction is shown at Fig. 286g, and in this the wheels are mounted in such a way that the steering is not interfered with while the power may be transmitted efficiently, re- gardless of the degree of inclination of the wheel. The axle consists of a substantial forged member having the wheel carrier mounted in a knuckle of the Mercedes type. The knuckle spindle bolt is in reality a driving shaft having bevel pinions at each end. The upper of these bevel pinions is in mesh with another member of the same size carried by a bearing member attached to the axle which serves to support a driving shaft which joins the sprocket at one end to the bevel gear at the other. The wheel is driven by a bevel gear which is rigidly secured to the wheel hub, and which meshes with the bevel pinion at the lower end of the intermediate drive shaft that forms the steering knuckle bolt. The power is thus transmitted from the sprocket, rigidly mounted on the axle through the medium of the bevel gearing and intermediate shaft to the driving member attached to the wheel hub. It will thus be apparent that the bevel gears on the inter- mediate shaft transform the rotation of the horizontal shaft to an equivalent rotary movement of the vertical intermediate drive shaft. With the gear construction described it will be possible to transmit power without interruption and with no more loss when the wheel carrying member is at an angle than when it is in the straight-ahead position. When the steering knuckle is turned by the arm bolted to it, which is controlled by the usual form of tie-bar and drag-link, as in conventional constructions, the driving gears do not vary their rela- tionship because the vertical intermediate drive shaft is mounted in such a way that it is independent of the movement of the wheel carry- ing member. It is claimed that the opportunity for power loss is con- siderably less with this system when the wheels are placed at an angle for steering than is the case when the drive is through universal joints. J The Modern Gasoline Automobile 555 : ^ Sprocket Fig. 286g. How Power may be Transmitted to a Combined Driving and Steer- ing Wheel without Universal Joints. The advantage of driving a vehicle by the front wheels is that liability of skidding is considerably reduced, and that the wheels serve to pull instead of push the vehicle. The front wheel drive system may be applied to chassis forms where it would be extremely difficult to use the rear wheel mechanical drive on account of having a very low carrying platform, as would be the case in vehicles designed to carry bulky and heavy merchandise. The front wheel drive system permits one to attach a low gear directly to the tractor frame and obtain in this way an efficient and effective motor vehicle for carrying heavy loads. 556 The Modern Gasoline Automobile Rear Axle Forms. In any motor car the rear axle is an impor- tant member as it combines two functions, one being that it is de- pended upon to support part of the car weight and that it must also drive the vehicle. The rear axle forms in common use are known as the " live " or " dead " types. The latter is the simplest and is built on the same principle as that generally utilized in horse-drawn vehicles. Two types of live axles are shown at Fig. 287. That at A is the simplest form and in this the wheel hubs are mounted directly on the axle shaft, and these members are depended upon to carry the weight of the car as well as to transmit to the wheels the power de- livered to the bevel gearing and the propeller shaft. In this construc- tion the axles revolve in roller bearings carried by the axle housing. The form shown at B is known as the " floating type " because the wheel hubs are mounted directly on the substantial housing member which is called upon to support the weight of the car. The wheels can revolve freely on the housing because they are mounted on ball bearings. The axles float in the housing and are called upon only to transmit power to the hubs and are not depended upon to sustain any of the car weight. The live axle depicted at A has been adapted to a certain extent on light cars, but the full floating type depicted at B is much more efficient and is used on heavy vehicles. It will be evident that should the simple form of live axle deflect under load the shafts will bind and considerable loss of power will obtain. In the construction out- lined at B the substantial housing members have ample capacity to sustain the load, and as the driving shaft does not become cramped through deflection it will deliver the power to the wheels much more efficiently. A strong advantage of the floating type rear axle is that the driving shafts and differential gearing may be removed without relieving the housing of the car weight. If it is desired to take the simple live axle shown at A apart it will be necessary to remove it from the car. The fixed or stationary axle construction is clearly shown at Fig. 287, C. In this the wheel hubs are mounted on ball bearings which permit them to revolve about the fixed axle spindle. The hubs are turned by chain connection with suitable driving sprockets on a coun- The Modern Gasoline Automobile 557 tcrslial't. The advantage of the fixed or stationary axle construction is that it is a much simpler assembly than the live axle forms, and as it may be constructed of few pieces it is apt to be considerably Fig. 287. Rear Axle Types Generally Used. A Live Rear Axle Using Shafts which Transmit Power and also Carry Weight Equipped with Roller Bear- ings. B Full Floating Type Bevel-Gear Drive Axle. C Stationary Axle with Chain Drive to Free Wheels. stronger than the built up live axles. It is contended that the lighter axle, which is practically free from any delicate mechanism, is more 558 The Modern Gasoline Automobile desirable because there is less weight carried directly on the tires. In the live axle forms some method of driving must be provided and some form of differential gearing must be included in the rear hous- ing. It is contended that while this construction is very suitable for light cars such as roadsters., or touring vehicles, that it would be extremely heavy if it was built of adequate strength to resist the stresses incidental to motor-truck operation. In the fixed or stationary axle with the wheels independent of each other, a differential gear must be provided just as much as in the live axle forms. This member is usually driven by gearing and must be installed on some form of a countershaft arrangement which Fig. 288. Combined Live and Stationary Axle which Combines Good Features of Both Types and Eliminates All Objections to Either. The Strongest Possible Construction. is attached to the frame. It is contended that mechanism supported by the frame which is mounted on resilient springs will not be so apt to get out of order as that which is attached directly to the axle, and which is kept from direct stress of the road shock only by means of the more or less resilient tires with which the wheels are provided. Axles have been evolved in which engineers sought to combine The Modern Gasoline Automobile 559 the strength of the dead axle with the efficiency of the live axle. One of these combinations is shown at Fig. 288. It consists of a sta- tionary load-carrying axle forging on which the wheels revolve, this serving to take the direct load of the car as well as serving as a support for the bevel gear and differential housing that receives the p<> \vt-r of the engine and directs it to the wheels by means of suitable shafts extending thereto from each side of the gear box. These com- posite forms are necessarily considerably heavier than either the live axle or the fixed axle forms as they are a combination of both, and as they are more expensive in first cost and add a large item to the unsprung weight of the car they are used very seldom at the present time. Purpose of Differential Gear. One of the most important elements of any form of automobile-driving system is the differential gear, but as this is usually placed at a point where it is not easily seen by the motorist and as but very little trouble is experienced from this mechanism, many owners of cars are not aware of its existence and do not realize the important work performed by this relatively simple component. Without a differential gear it would be difficult to con- trol the machine when driving around corners, so this really performs an important function with both steering and driving systems. When turning corners with a four-wheel vehicle the outer wheels must turn at a higher rate of speed than the inner ones because they are describing a larger arc of the circle. The more sharply the vehicle is turned the greater the difference in velocity between the inner and outer wheels. In a horse-drawn conveyance all the wheels are independent of each other and may all revolve at different speeds if necessary, without interfering with each other or impairing the ac- tion of the conveyance. In an automobile different conditions prevail because while the front wheels are usually independent of each other, the driving wheels must be connected together so that each will receive its share of the energy produced by the motor and will perform its quota of the work incidental to propelling the vehicle. In order to permit one of the driving wheels to turn at a lower speed than its mate in rounding a corner the balance or differential gear is used. Its simplest application is shown at Fig. 289. From this it is patent that the driving axle is split in the center and that 560 The Modern Gasoline Automobile the wheels are mounted on and driven by distinct shafts. At the inner end of each shaft a bevel gear is carried, these being firmly se- cured to the axles so they revolve with them. The main bevel-driven gear, which is actuated by thej..dsivi^ff pinion turned by the engine Fig. 289. Illustrating Differential Gear Action when Applied to Bevel-Geat Drive Axle. shaft, is mounted independent of the axles and is coupled to them by means of small bevel pinions which are applied so that they will drive the gears on the axle shafts. Assuming that all the gears are in mesh, as outlined, and that power is being applied to the driven gear, and that the resistance to traction is the same at both rear wheels, the entire assembly comprised of driven gear, the differential pinions attached to it and the axle shafts revolve as a unit. If the resistance against the driving wheels varies so one wheel tends to revolve faster than the other, the differential pinions will not only turn around on the studs on which they are mounted, but at the same time will run around the gears on the axle shafts, because the bevel-driven gear is carrying the studs on which the differential pinions revolve forward. When turning a corner the outer wheel must turn so much faster than the inner member that it is just the same as though one of the wheels was held stationary and the other The Modern (Inxoline Automobile 561 turned. If botli wheels are turning forward at the same speed, the differential pinions remain stationary and act simply as a lock which forms a driving connection between gear No. 1 on axle shaft No. 1 and gear No. 2 on axle shaft No. 2. This will mean that both wheels must turn in the same direction as long as the work is uni- formly distributed. Just as soon as the resistances are unequal the differential pinions will turn on their supporting stud, and one mem- ber may turn at comparatively slow speed while the other revolves at a much faster rate. The action of the differential pinions may be clearly understood by reference to Fig. 289 and giving due consideration to the follow- ing principles: The same resistance at the point of contact between the driving wheels and the ground prevents the pinions from revolv- ing on their own studs, and in this case they are carried around by the supporting members and the ring gear. If the resistance upon axle shaft No. 1 is greater than that on axle shaft No. 2, the ring gear will rotate forward with the wheel offering the least resistance and the differential pinions will turn on their studs and run over the surface of the gear which tends to remain stationary, this being the one against which there is the greatest resistance. The differential pinions can thus turn independently of one gear wheel and run over its surface without turning it, and at the same time act as a clutch- ing member of sufficient capacity on the other gear and axle to carry them in the same direction as the ring gear and at a ratio of speed which will depend upon the difference in resistance between the driv- ing members and the ground. While the differential gear described is of the bevel pinion type, other forms have been devised in which the differential action is obtained by means of spur gearing which utilizes the same principle of compensation. Various friction and leverage combinations have been adapted in an endeavor to secure a differential action, but these have eventually been displaced by the simpler and more * efficient geared forms. The differential gear which utilizes bevel pinions is the form that is more generally used, and has proved to be the most cilicii nt and enduring. The differential gear is usually incorporated iu the rear axle if the drive is by shaft or single chain, and in the countershaft if transmission is by means of side chains. The con- 562 The Modern Gasoline Automobile struction of typical differential gears and bevel-driving gear assemblv is clearly shown at Figs. 290 and 291 ; the former is utilized on light vehicles and is mounted on flexible roller bearings, while the other Bevel Gear Roller Searing: Differential Gears Fig. 290. Bevel-Gear Drive Assembly of Ford Light Cars Mounted on Hyatt Flexible Roller Bearings. construction is a type more suitable for heavier cars and is mounted on tapered roller bearings. Worm-Gear Driving. A number of designers have used worm gearing in connection with shaft-driving systems instead of the bevel gears so generally adapted. The greatest development of worm driv- ing has taken place abroad, and very efficient and enduring mech- anisms have been evolved. The advantages of the worm gear are more apparent in motor-truck construction than in pleasure-car prac- tice, though it has been used to advantage in both classes of vehicles. A high degree of efficiency has been obtained by using worms of peculiar tooth formation which have a spiral angle often approaching 45 degrees. Such worms may have from six to ten or twelve threads, The Modern Gasoline Automobile 563 and they are perfectly reversible, when contrasted to the single- threaded worm used in steering gears, which are an irreversible form. Obviously the worm employed for driving an automobile must be perfectly reversible to be practical, as very often conditions will be Pinion Drive Shaft Bevel Driving Gear Axle Shaft Differential Gearing Taper Roller Bearing Housing Cover Fig. 291. Bevel-Gear Drive Assembly Mounted on Timken Tapered Roller Bearings. such that the rear wheels and worm gear to which they are attached must turn the worm and driving shaft, as in descending hills, with the rear axle overrunning the engine. This form of gearing offers many inducements and has positive advantages which commend it as a means of direct final drive. Any range of reduction that would be likely to be needed may be obtained with but a single pair of worm gears, and reductions of twenty to one may be as easily accomplished as securing the higher ratios without the efficiency of the combination being affected. It would not be possible to obtain as low speed reduction as possible with worm gear- ing by the use of a single set of bevel gears or a single pair of sprockets 564 The Modern Gasoline Automobile and chain connections, because the driven member would have to be of such large size that it would be difficult to place it within the confines of an ordinary axle. It is for this reason that most motor- truck manufacturers use a combined bevel gear and chain drive and a double reduction of speed between the engine and the rear wheel. Among some of the advantages advanced in favor of worm gear- ing may be cited : It is silent in operation ; when properly designed it will transmit eighty-five to ninety per cent cf the engine power to the rear wheels on direct drive, and it is extremely enduring. Its efficiency under ideal conditions is equal to the most accurately ma- chined and finely adjusted bevel gearing, and instead of the efficiency becoming less as the gearing .wears, it actually becomes more silent and freer running with use. Many of the more progressive manufacturers of automobiles are giving the worm and worm-gear drive that consideration which means its eventual adoption. It has been used with success in pleasure-car applications, but its greatest field of usefulness will undoubtedly be Drive Shaft '^m Fig. 292. Worm-Gear Driving Assembly Utilized on Pierce Motor Trucks and Form of Worm and Worm Wheel Utilized in Power Transmission. the commercial vehicle industry because of its undoubted superiority over all other forms of gearing from which considerable reductions in ratio are demanded and where the efficiency of the transmission system should be conserved as much as possible. A typical worm- gear assembly and the method of mounting the worm in connection with the shaft drive is shown at Fig. 292, while the illustration at The Modern Gasoline Automobile 565 Fig. 293 shows clearly the application of worm and w,orm-wheel drive in a live or floating axle construction. Worm. Worm Casing. Worm Gear Worm Ball Thrust Bearing Radial Load Bearing Spring Pad. Fig. 293. Worm-Gear Driving Axle Used on Dennis (English) Motor Cars. Axles Employing Double Reduction Gearing. The simplest form of axle in which two gear reductions are necessary is the stationary or dead axle, but it must be used with the jack-shaft combination previously described. There is one gear reduction by means of bevel driving gearing in the countershaft assembly, and the ratio between the driving sprockets and the driven members attached to the wheel may be altered so a wide range of speed may be obtained. The use of a separate countershaft assembly is favored by the majority of builders of motor cars who find it necessary to use two speed reduc- tions in the driving gearing, and one of the objections which has been advanced against the use of exposed driving chains has been 566 The Modern Gasoline Automobile overcome in many designs by the use of oil-tight chain cases that protect both chains and sprockets from grit and dirt and insure effi- cient operation because the chains operate in an oil bath. If a driving chain is kept properly adjusted and remains clean and well oiled its efficiency will be very high, and chain cases are very desirable attachments to attain these ends. The usual form of chain case is depicted at Fig. 294. In this construction the case proper is composed of an aluminum casting which is also utilized as a distance member to maintain a fixed relation between the front sprocket and that on the driving wheel. When the cover is in place Driving Chain Front Sprocket Wheel Sprocket' Fig. 294. Method of Enclosing Driving Chain in Oil-Tight Casing to Secure Efficient Driving and Long Life of Mechanism. the assembly is oil-tight and the chain and sprockets always receive adequate lubrication, which tends to greater endurance and main- tenance of efficiency. Some engineers do not favor the chain-driving method, and when a double speed reduction is necessary between the motor and the driving wheels it is incorporated directly in the rear-axle structure. A combination axle of this type, known as the " Torbensen," is de- picted at Fig. 295. This is in reality a combination of the live and dead axle forms and has been designed specifically for application in motor-truck work. The differential gear is carried in the casing attached to the back of the fixed axle and receives power from the engine through the drive shaft and a pair of bevel gears. The wheels are mounted directly on the ends of the fixed axle and are driven fro: The Modern Gasoline Automobile 567 the differential gear by means of axles extending therefrom and carrying driving pinions of the spur type which mesh with internal Fig. 295. Sectional View of Torbensen Axle for Motor Trucks which Combines Features of Both "Live" and "Dead " Rear Axle Forms and which Utilizes Two Driving Gearing Sets. gears attached to the wheels. It will be evident that one reduction of speed is obtained at the bevel gearing, and this would be further Drive Shaft. Spur Gear. Fig. 296. Live Rear Axle with Combined Bevel-and Spur-Gear Final 568 The Modern Gasoline Automobile reduced by the difference in ratios between the spur-driving pinions and the internal gears carried by the wheels. The live-axle form shown at Fig. 296 is that used on some of the Peugeot (French) cars and also uses bevel and spur reduction gears. In this case, however, but one spur gear is used to drive both wheels, this being attached directly to the differential gear case, and the wheels are turned by live floating axles. The first speed reduction is by means of the bevel gears, one of which is driven by the motor, the other being attached to the countershaft, which also carries the small spur-driving pinion, which meshes with the large gear on the dif- ferential case. The efficiency of either of these axles will be about the same as that of the combination countershaft and side-chain drives, but those who favor the latter construction advance the argu- ment that combining a double reduction on the axle makes for greater unsprung weight than is desirable, whereas carrying the countershaft on the frame makes it possible to support it on springs, just as the greater part of the power-generating and transmission mechanism is. Utility of Motor-Car Brakes. One of the most important of the components of the motor-car controlling system is usually carried with and forms part of the rear construction, this being the braking means which is utilized to bring the vehicle to a stop when it is de- sired to arrest forward or backward motion. It will be evident that in a horse-drawn vehicle the animal drawing it can be used as a brake, but that in any form of self-propelling conveyance it is essen- tial that some means of stopping be included in the construction. Even if the clutch was operated in such a way that the motor was disconnected from the driving wheels the conveyance would continue to move because it had acquired a certain momentum which would increase in value with the weight of the car -and the speed at which it was driven. On some forms of horse-drawn vehicles, particularly those of large capacity, some form of supplemental retarding member must be provided to assist the braking effect of the animal, which may not be sufficient to stop the vehicle when descending grades or when operated with some degree of speed on the level. A simple form of shoe brake, such as used on a horse-drawn con- veyance, is shown at Fig. 297. This consists of a brake block of The Modern Gasoline Automobile wood or other material carried at the end of a fulcmmed lever, which in turn is joined to a pedal by a connecting link. When it is desired to bring the vehicle to a stop, a moderate degree of pressure at the Brake Blocks Steel Tire.- Fig. 297. Simple Form of Shoe Brake Used on Horse-Drawn Vehicles. foot pedal will bring the brake block in contact with the periphery of the wheel, and but a very moderate amount of pressure suffices to lock the wheel in a positive manner. This construction could not be very well applied to motor vehicles, because the action of the shoe against the rubber tire would be apt to produce rapid depreciation of these costly elements. For this reason the brakes of automobiles are t-s 1 M-ci ally -designed so that they will wear instead of producing deteri- oration of the points to which they are applied. Forms of Motor-Car Brakes. The braking members generally used on automobiles may be divided into two classes, each of these depend- ing upon the property of frictional adhesion between substances In- Id together by considerable pressure. The usual construction is to 570 The Modern Gasoline Automobile attach a drum to some portion of the change-speed mechanism, to the differential gear or to the wheels themselves. At the present time most engineers favor applying the brakes directly to the driv- ing wheels, and pressed-steel drums are usually fastened to these members, against which the brake acts. The retarding effect may be obtained either by an internal expanding shoe brake or by an external contracting band brake. The principal forms are outlined at Fig. 298. That at A con- sists of an internal expanding member consisting of two shoes which Fig. 298. Internal and External Band Brakes Used on Motor Car Wheels. conform to the arc of the brake drums. These are spread apart and brought into forcible contact with the drums by means of a simple lever and toggle linkage. Another method of expanding the internal band so it will engage the inner surface of the drum is out- The Modern Gasoline 571 lined at B. In this the toggle linkage is replaced by a cam which is rocked by the lever to force the brake shoes apart when it is moved in one direction, and permits them to close up and release the drum when it is rocked the other way. External Brake Internal Service Brake Internal Emergency Brake Fig. 299. Typical Automobile Brake Forms. A Two Internal Bands. B Double Expanding Type. C External and Internal Brake Combination. The brake shown at C consists of a steel band which is lined with some friction material possessing considerable resistance to heat, such as asbestos-wire fabric. The band is attached to a double-bell crank lever in such a way that it will be brought into forcible engagement with the external surface of the drum if the end of the lever is moved in the direction of the arrow. Another form of band brake is depicted at Fig. 298, D. This is a much more efficient form than that outlined at C and it has great holding power. The band may 572 The Modern Gasoline Automobile be adjusted as the friction material wears, and thus the brake may be always kept in perfect adjustment. The methods in which the brakes are usually mounted in auto- mobiles are clearly shown at Fig. 299. At A two internal expanding bands are mounted inside of each brake drum, one pair of these being connected to a pedal and used as a service brake, while the other is attached to a hand lever and is depended upon as an emergency or Wheel: Fig. 300. Typical Automobile Brake Assembly with Rear Wheel Removed to Show Application of Brake Drum to Wheel and Internal and External Bands on End of Axle. auxiliary braking member. The cast shoes are hinged at their lower end and are faced with friction material. They are spread by means of cam expanders, and when the shoes are spread apart they engaj The Modern Gasoline Automobile 573 the inner portion of the brake drums with considerable force and retard its motion. The brakes shown at B are similar in operation to those outlined at A, and the assembly is presented merely to show the relation of the brake shoes to the axle on which they are mounted. A combination of internal expanding and external constricting brakes is shown at Fig. 299, C. This is a very common method of construc- tion and is found on many cars. The inner brakes are usually de- pended on for emergency service, while the outer brakes, which may be more easily applied, are used for braking under ordinary condi- tions. A common brake drum serves both brakes, as the expanding member will engage the inner periphery, while the external band will contract around the outer face of the drum. The method of install- ing the brake on a typical motor-car rear construction is shown at Fig. 300. The braking members in automobiles have been mounted on both front and rear wheels, on the jack shaft of a double-chain driven car, Yv r hecl Hub Ball Bearing Fig. 301. Rear Hub of Metz Car Showing Multiple-Disk Brake. or on the propeller shaft of a bevel- or worm-gear drive arrangement. Brakes are not always of the internal or external band form, some designers having used other combinations to obtain the same results. The multiple-disk brake employed on the Metz car is shown at Fig. 301. In this a series of disks is attached to and revolves with the wheel hub, while another group is fixed to the stationary axle. Pressure is brought to bear against one of the fixed disks by means 574 The Modern Gasoline Automobile of pressure pins passing through one of the wheel-supporting cones, and this is in turn communicated by each disk to its neighbor. The same object is attained as in a multiple-disk clutch and a larger amount of braking surface is obtained by using a comparatively large number of small diameter disks instead of two larger members, which might not have as much effective surface. Multiple-disk brakes have been used to some extent on foreign cars, but this is the only instance to the writer's knowledge where they have been applied on a domestic product. Side slipping or skidding is one of the dangers of motoring on highways which may have a slippery surface. If one turns the corner of a wet asphalt, macadam, or clay pavement a certain amount of side-slipping action will be evident, and if the brake be applied at this time this skidding tendency will be accentuated. The skidding tendency of a self-propelled vehicle is most noticeable when the brakes are applied suddenly to the rear wheels, and it is evident by a swing- ing movement at the rear end of the car which tends to bring the braking wheels around to the front in the direction in which the car is moving. Various means have been proposed to eliminate this side- slip action, and numerous forms of tire chains, studded tire treads or treads with knobs or other projections of rubber molded integral with them have been devised to minimize the skidding tendency. Application of Front-Wheel Brakes. A number of foreign engi- neers have applied brakes to the front wheels instead of the rear members to reduce the skidding action. It is claimed that the appli- cation of brakes to the steering members instead of the driving mem- bers will eliminate the skidding tendency, because the braking action would be on the wheels which were already at the front end and pointing in the direction in which the car was moving. There are a number of disadvantages which militate against the general adop- tion of front-wheel brakes, these being of a nature which makes them extremely difficult to surmount successfully. In the first place, it is rather difficult to mount the brakes on the steering knuckles and operate them from a fixed portion of the car. Then, again, the usual front axle, as designed at the present time, is not adequate to resist the torsional stresses which obtain when the motion of the car is stopped by arresting the rotation of The Modern Gasoline Automobile 575 the front wheel, and some form of torque member would have to be provided to take care of this strain. This would mean considerable mechanical complication which is not necessary, as when the brakes are applied on the rear wheels one common member may be used to take both braking and driving torque stresses, and this member would be needed, even if the brakes were applied to the front wheels, in order to take care of the driving torque. If brakes are applied to all four wheels, some arrangement must be provided by which the front-wheel brakes could be applied first to do away with the tendency to skidding, while the rear brakes would be called upon to add to the braking effort already provided. The principal difficulty in fitting up front- wheel brakes is in the arrange- ment of the operating parts. These must be attached to the vehicle frame at one end, and must also be supported on the axle at the other, and as the axle is free to move relative to the frame it will be evident that the problem of providing a flexible and positive brak- ing connection will be made more difficult of solution when one con- siders that some provision must be made for the angularity of the wheels when turning corners. This would mean that the operating mechanism on one side must shorten, while that at the other side must lengthen in some way to compensate for the difference in angu- larity of the brake drums. Whatever form of brake actuation is used it must be designed so these members will be applied with equal force and at the same time in each wheel. This problem is not a difficult one when the brakes are attached to the rear axle, but it is not easy to operate front- wheel brakes in a positive manner and insure that each will be applied with equal force. Various forms of front-wheel brakes are shown at Fig. 302. The design shown at A is a cam-expanded shoe which is mounted on an extension of the steering spindle. The cam is rocked .by means of a lever attached to it, which is moved by a pin passing down through the steering knuckle bolt and resting against the end of a bell-crank form of brake lever carried by the axle. When the brake lever is moved the movement of the end against which the pin rests is trans- mitted to the cam which spreads the shoe by means of the pin pass- ing through the steering knuckle. Another form of cam-expanding brake is outlined at B. In this the cam is rocked by a lever which 576 The Modern Gasoline Automobile passes down to the bottom of the steering spindle, where it is coupled to the operating gear by means of a steel- wire cable passing around a roll at the end of the steering-knuckle bolt designed to give a cer- Fig. 302. Types of Front- Wheel Brakes that Have Been Used on British Auto- mobiles Showing Novel and Ingenious Methods of Brake Actuation. tain degree of universal motion. The shoes are kept from rubbing against the inner face of the drum by a coil spring joining the upper The Modern Gasoline Automobile 577 extremities of the shoes to keep them in contact with the cam face. The brake shoes are supported at the bottom in adjustable yokes which may be moved out to compensate for wear of the brake-shoe surfaces. The method outlined at C is that used in the Argyl (Scotch) motor car. In this form the brakes are operated directly from the frame side instead of by bell cranks or wire cables attached to the axle. The brake is a cam-expanded shoe type, the cam being moved by a brake-operating rod, extending from the frame-side member to the top of the fixed member employed to carry the brake band which forms part of the steering knuckle. The brake-operating rod is pro- vided with a pair of double ball-and-socket universal joints and is operated by means of a small lever attached directly inside of the frame-side member. Front-wheel brakes have not been used to any extent on American motor cars, but they have been applied in quite a number of instances abroad. The advantages advanced by the English designers for this peculiar form of brake are chiefly centered around the factor of eliminating skidding and of being more accessible and easier to adjust than the rear-wheel brakes. Against these advantages one may ad- vance the disadvantages of complicated operating mechanism, the possibility of unequal braking effort, and the interference with posi- tive and correct steering should some one of the universal operating rods become stuck in such a way that it would not permit the wheel to turn as it should. Skew Bevel Drive Gearing. The skew bevel or worm bevel, as it is sometimes called, differs from the regular form of bevel gear in that the teeth on pinion and ring gear are cut on an angle, as in worm gearing. The construction of typical skew bevel driving gears detached from the differential casing is shown in illustration Fig. 302a. It is claimed that the skew bevel produces increased quietness of drive, as backlash or looseness between the teeth, which is a common cause of noisy action of conventional bevel gearing, is entirely eliminated by the angular teeth. It is also claimed that whereas ordinary bevel gearing has a straight line contact that the worm bevel with its curved teeth has one set of teeth constantly meshing while the next 578 The Modern Gasoline Automobile Skew Bevel Gee^r SKew Bevel Pin,ior\ Fig. 302a. The Packard Skew Bevel Driving Gearing. set is becoming disengaged. This affords a continuous contact, in some degree the same as accomplished with worm gearing. Two-Speed Direct-Drive Axle. This is an axle construction of recent development and is called the two-speed direct-drive axle be- cause, in place of a single bevel pinion and ring gear used in the ordinary construction, there are two bevel pinions and two ring gears attached to the differential casing. A typical assembly of this nature is shown at Fig. 30"2&. The drive pinion B is integral with the drive shaft and always revolves with it, .while the larger drive pinion A only revolves with the drive shaft when the sliding clutch A is engaged with the corresponding clutch member attached to the pinion. When the sliding clutch A is shifted into position, the actuating bell The Modern Gasoline Automobile 579 580 The Modern Gasoline Automobile crank shifts another sliding clutch attached to the differential gear case which releases ring gear B and allows the engine to drive the differential casing and the gearing it contains through the medium of drive pinion A and ring gear A. When the other ratio is desired, the positive clutch-shifting lever is moved so that it brings sliding clutch A out of engagement, which causes a simultaneous movement of sliding clutch B so that ring gear B is clutched to the differential casing. It will be apparent that the drive is through only one set of gears at a time, the set that is not in use revolving idly on suitable bearings. This construction affords two gear ratios, each driving direct from the engine to the wheels without any intermediate gearing other than the regular driv- ing gears ordinarily employed in a one-speed axle. It is contended that no one single gear ratio can be just right for all vehicle speeds and all road conditions. The usual gear ratio of a single direct-drive axle ranges from 3.5 to 1 to 4 to 1, according to the weight and power of the car. If a car is geared low, higli speeds can only be obtained by racing the engine, but its hill-climbing abili- ties on the high are excellent. At the other hand, if the gear ratio is such that the car can be operated at high speed without racing the engine, it will be a poor hill climber and the low gears will have to be resorted to ,on any gradient of magnitude. In the axle shown* there are two gear ratios, one of which is low, and which is especially adapted for city driving, where starting, stopping, and slowing down are frequent and where cautious operation is necessary. When con- ditions are more favorable, the higher direct-drive gearing may be brought in action, and higher vehicle speeds are possible without a corresponding increase of engine revolutions. For example, with the lower direct-driving gears in operation, an engine speed of 700 revolutions per minute would mean a car speed of approximately 20 miles per hour, whereas if the high direct- drive gears are used the car will travel approximately 30 miles per hour, with no increase in engine speed. This increase in car speed without a corresponding increase in crank-shaft revolutions means that there is a decrease in fuel consumption for a given mileage. A given quantity of gas is utilized to greater advantage and produces more actual power at the rear wheels than with the engine turning The Modern Gasoline Automobile 581 over more rapidly on the low gear ratio. Friction and wear of power plant and transmission gearing are also materially reduced, because the parts are operated more slowly. When a low gear ratio is employed a car will vibrate very much at high vehicle speeds on account of the great speed at which the motor is operating, while with the higher ratios there is comparative freedom from vibration, because the power plant is not operated at excessive speed. Differential Locks. Under some conditions it is undoubtedly a great advantage to be able to temporarily lock the differential of a truck against action. Whenever one wheel is so situated that it slips readily while the other is on ground affording good traction, the truck can generally be moved if the differential is locked. This condition is sometimes met when one wheel is in a mud hole or on a wet spot of pavement, and it is most acute in the winter when the streets and roadways are icy so that one wheel may get on ice and obtain prac- tically no traction. Differential locks have been known at least since 1903, when they were applied on one steam freight wagon built in this country and on an English steam lorry, but they have not been very extensively used on trucks so far. Among the advantages which the differential lock offers may be mentioned that it frequently obviates the necessity of using chains, mud hooks, and similar devices, because when any vehicle is unable to obtain traction it is generally found that only one of the wheels is slipping. This advantage would be more apparent when a trailer was being used, because it is harder to get sufficient traction to draw a trailer. It would also be more important if wood block or metal tires were used. Of course it takes considerable time to put on chains and to remove them in order to get out of a difficult position, while if the chains are left on they unnecessarily consume power, and, more- en 7. That at A einii]i-.y> a series of radial compression springs which provide the resilient feature, while the strength is obtained by means of the plungers fastened to the upper member which is attached to the wheel rim; these in turn fit the cylinders attached to the outer periphery of the inner wheel. The spring serves to keep these mem- 596 The Modern Gasoline Automobile bers separated at all times. In the construction outlined at B the spokes are flat springs, curved in a peculiar manner, and join the central hub member with the outer rim. Neither one of the forms shown have been adapted practically, and the illustrations are presented merely to show freak constructions which have but little practical value. It may be said of all forms of spring wheels that their disad- vantages are of sufficient magnitude to make those which are advanced against the pneumatic tire seem simple by comparison. While pneu- matic tires may fail on the road, they may be easily restored or repaired and the journey continued with but little interruption. If members of a spring or resilient wheel should fail in service the work of replacement would entail a degree of mechanical skill not usually possessed by the average motorist. Many inventors have given this problem considerable attention, but it is safe to say that the rubber tire in either of its forms is absolutely necessary to successful motor- vehicle operation, and that there is but little future for resilient wheels depending on springs or other metal resilient members to cushion the shocks met with when traveling over ordinary highways. Forms of Automobile Tires. The wheels of automobiles, with but few exceptions, are provided with rubber tires. The simplest is a solid band of rubber composition ; next in order we have the various forms of cushion tires in which the band of rubber is perforated with a number of small holes or provided with a series of openings de- signed to provide greater resiliency and make the tire more yielding than the solid-rubber form. Solid tires are invariably adapted to industrial conveyances. The most common form of tire, and that generally used on auto- mobiles, is composed of a hollow rubber tube of circular section filled with air and protected from wear by means of an outer shoe or casing. The use of air under compression provides a very resilient medium for supporting the vehicle, and of the various forms of rub- ber tires the pneumatic form is the one that is the most desirable. The development of the modern automobile may be attributed largely to the advances made in pneumatic-tire construction, as these mem- bers made it possible to drive automobiles at high speed over rough road surfaces without stressing the mechanism or causing discom- The Modern Gasoline Automobile 597 fort of the passengers. While solid-rubber tires and members of the cushion form have a certain degree of elasticity, they do not ride as easy as pneumatic tires, because rubber cannot be compressed, but only distorted. Solid-rubber and cushion tires are suitable where vehicle speeds are low, but are very unsatisfactory for automobiles traveling at speeds over fifteen miles per hour. Fig. 308. Comparison of Action of Pneumatic and Solid-Rubber Tires when Wheel Rides Over Obstacle. A comparison between the action of pneumatic and solid-rubber tires is made at Fig. 308 so the superiority of the latter form may be readily understood. At A, a wheel shod with a pneumatic tire is shown in contact with an obstacle in the road. When the wheel 598 The Modern Gasoline Automobile passes over this obstruction, the walls of the tire, which are rela- tively light, will deflect inward and compress the air inside of the tires. The wheel is not raised from the ground and the vehicle rides over the obstruction without any appreciable upward movement or throw of the chassis. At B a solid rubber tire is shown passing over the same obstacle. In this case the composition is so stiff that it will not bend in and the wheel is. raised from the ground. This throws the vehicle body upward, jarring both mechanism and pas- sengers. The severity of the jolt augments proportionately to the speed of the vehicle. It will be patent that the form of tire depicted at A, which permits the stone to imbed itself into the tire, will be much more easy riding than that form which will ride over the obstacle. The great advantage of a pneumatic tire is that it will give more than ordinary elasticity to the wheel and will absorb most of the minor shocks that would be transmitted to the springs of the vehicle if noncompressible tires were used. Construction of Pneumatic Tires Defined. The pneumatic tire of the present day is invariably of the double-tube type and is com- posed of two members, the inner tube and the shoe or carcass. The inner member is utilized to retain the air and is made of a very pure rubber, about an eighth of an inch thick for cars of average weight. While this tube is very elastic and is air-tight, it would not be strong enough or have adequate resistance to be run directly in contact with the road surface; therefore it is necessary to protect it by a shoe composed of layers of fabric and rubber composition. The shoe member is provided with beads on its inner periphery designed to interlock with the rim channel, as shown at Fig. 309. The main portion of the outer casing is composed of five or more layers of a Sea Island cotton fabric " frictioned " with high-grade rubber composition. This is forced into the mesh of the cloth by machinery so the fabric will be practically waterproof and will join intimately with the other plies by a process of vulcanization when the shoe is cured. Outside of the fabric body a layer of very resilient rubber, approximately of crescent form, known as the padding, is provided to give a certain degree of elasticity to the shoe. Between this member and the tread a number of pieces of heavy fabric called " breaker strips " are interposed to offer a certain degree of resistance Tread Padding Breaker Strips Rim Channel Felloe Valve Inside Valve- Cap Kig. 309. Outlining Construction of Pneumatic Automobile Tire Fitted to Sim- ple Clincher Rim. 599 600 The Modern Gasoline Automobile to any sharp object that might penetrate the tread and go through the padding and into the fabric body if the breaker strips were not interposed to deflect the puncturing object to one side. Valve Closed Valve Open Fig. 310. Construction of Schrader Universal Tire Valve. The tread is the part of the tire that is subjected to the greatest stress, as it must resist the abrading influence of the road and, when The Modern Gasoline Automobile 601 the tire is used on the rear wheels, the wearing effect of the friction produced by the tractive effort which exists at the point of contact 1 >ft ween the driving member and the ground. The tread is of very tough rubber composition and differs from the material used as padding or for the inner tube in that it does not possess a very great degree of elasticity. This quality is sacrificed for that of greater strength and resistance to wear, which is more essential at this point. The air is introduced into the tire through a simple form of automatic valve which is securely attached to the inner tube. As the inner tube becomes distended by the air pumped into it, it forces the beads of the tire outward and clinches the shoe so firmly in the rim channel that it will be impossible to dislodge it without the use of special tire irons, and then only when the air pressure is relieved from the inner tube. A detailed view of the valve stem in the open and closed position is shown at Fig. 310, and the construction of this simple fitting can be easily understood. The valve is held againfct its seat by a tension spring and will only open when the valve stem is depressed by the hand or from the pressure of the air forced against it when it is desired to inflate the tire. While the air pressure from the pump will be sufficient to force the valve from its seat, the air pressure from the inside of the tire only serves to hold it more firmly in place. Pneumatic tires are not always of the clincher form. Various other constructions have been devised, some to facilitate a more ready removal than the clincher construction permits, while others have been designed to make for a more secure attachment by some me- chanical means. Various forms of quick-detachable rims and the tires adapted for use with them are shown at Fig. 311. In the ordinary clincher tire it is necessary to force the bead over the chan- nel when it is desired to remove the outer casing, and while this can be accomplished with comparative ease on the smaller tires, it is very difficult to remove or apply large clincher tires. In the form shown at A the clincher rim is made in two parts, one of the sections being easily removable when the locking ring is taken out of the groove in which it fits. When the movable section of the rim is taken off the outer casing may be easily removed, as it can be slipped off 602 The Modern Gasoline Automobile the fixed portion of the rim just as a belt can be removed from a pulley. The Dunlop type of outer casing is depicted at B and C, these also being fitted to quick-detachable rims. In the Dunlop casing Fig. 311. Forms of Quick-Detachable Rims which Permit Easy Removal of Pnematic Tires. retention is by a series of steel wires at the base of the tire which have a certain amount of holding power, which is further augmented by The Modern Gasoline Automobile 603 tin- air pressure inside of the tube. It is claimed for this construc- tion that it is more easily removed than the clincher tire when applied to a one-piece rim, though on the quick-detachable type shown in illustration one form is as easily removed as the other. The rim shown at A and B is the same member, and it will take either clincher or Dunlop type casing. When used for the latter a rubber filler rinu is provided to fill the channel of the fixed portion of the rim, while the flat side of the removable portion is brought in contact with the casing walls instead of the channel or hooked side. The fnnii shown at C is made exclusively for use with Dunlop type casings, and cannot be utilized for clincher tires. At D the Fisk bolted-on casing is shown. This differs from the other forms in that the clinchers are designed in such a manner that they practically form a foot or base, and when closed together will keep the inner tube away from the rim, which is not done with the other forms of rims. The rim proper consists of a flat band of steel attached to the wheel felloe. Two locking rings are provided, one at either side of the tire, and these are held into proper relation and clamped tightly against the base member of the shoe by means of bolts which pass through the enlarged beads of the casing. This form of attachment is very secure and the tire is held to the rim by mechanical means as well as air pressure. In other forms of tires in which air pressure alone is depended upon to keep the beads in contact with the rim it is possible for tires to be thrown off the wheels if they become deflated, though with the mechanically fastened form, as shown at D, the tire will be held in place, even when par- tially deflated, much more securely than in the other forms. The construction of inner tubes is practically the same in all standard makes of tires, and these are usually interchangeable. The outer casings differ in some respects, these being merely a matter of detail involving the number of plies of fabric, the thickness of the padding, the arrangement of breaker strips, and the character of the tread. All the tires shown at Fig. 311 have the plain round tread, which is the most satisfactory for all-around use. The smooth nv:id, however, has the disadvantage in that it is liable to slip on muddy roads, and for this reason a number of tread forms have been to secure greater adhesion to the road or to reduce wear. 604 The Modern Gasoline Automobile A round-tread tire will wear off until the breaker strips are exposed, and the tire should be retreaded as soon as this condition is apparent. The casings shown at Fig. 312 are a few of the forms which have been designed to secure greater wear of the tread. In that shown at A the tread is raised at five portions and is very thick. In that shown at B the tread is provided with a large number of small Fig. 312. Showing Various Raised Treads Used on Pneumatic Tire Casings. rubber studs or projections which are depended on to prevent side slip more than providing any great amount of added wear to the tread. The form shown at C is known as a raised-tread type, and in this the round tread is reenforced with a flat band running around the outer periphery, this providing a greater thickness of tread than will be possible with the round-tread construction. The leading forms of treads designed to secure greater traction than that obtained from the plain-tread forms are shown at Fig. 313. In the Morgan & Wright, shown at A, a large number of knobs are molded integral with the tread to prevent skidding. The Empire casing shown at B has a number of disks composed of strips of fabric rolled up and set edgewise in the tread to promote adhesion. In the Swinhart, which is depicted at C, strips of rubber are molded with the tread to form a species of basket weave. This prevents skidding, because the spaces between the strips will fill with mud or dirt and will not slip over the road surface as readily as a smooth tread. The casing shown at D is provided with a number of rings molded with the tread to form little cups which grip the road by the suction effect The Modern Gasoline Automobile 605 of the air compressed between the tire and the road surface in the depressions. The Ajax nonskid tread depicted at E is composed of diamond-shaped rubber pieces molded integral with the tread when the tire is cured. A very ingenious method of roughening the sur- face of the tread to promote traction is that used on the Fire- stone casings. In this the words " Firestone " and " Non-Skid " are molded in bold lettering alternately and at an angle all around the shoe. The Harford Midgeley tread is depicted at G. This construc- tion has a series of coil springs molded around the outer periphery of the casing. The Diamond casing outlined at H utilizes the Bailey rubber-stud tread, one of the first antiskidding treads to be devised. In the Michelin casing illustrated at I, a leather band provided with steel studs, which are riveted through it and the casing, is depended on to prevent skidding, to secure improved traction, and to make the casing practically puncture proof from ordinary road obstacles. The Republic Staggard tread tire is shown at J. The principle of providing a large number of projections which is used in the forms depicted at A, D, H, I, is followed on this casing as well, but these knobs are of such size the liability of rapid wear, which is present when rubber buttons of comparatively small size are used, is reduced and the life and antiskidding properties of the tread are augmented proportionately. While the nonskidding forms of tires have peculiar advantages which adapt them for use on soft and slippery roads, they are more expensive than the round-tread casings, and are really not needed a large part of the time. The labor of changing from the antiskid type of tread to smooth casings would be considerable, and it would not be practical to make the changes as often as conditions imposed by our variable climate would make necessary. For this reason a num- ber of auxiliary treads and nonskid devices have been placed on the market, the idea being to use these in conjunction with the plain- tread tires when necessary. These auxiliaries may be divided into two classes. First, those designed merely to promote better tractive effort and eliminate skidding, and, secondly, those which have been designed to act as a protector for the casing of rubber which they encircle. 606 The Modern Gasoline Automobile 607 A number of these auxiliaries are shown at Fig. 314. That at A is a leather tread provided with steel studs on the tread surface, made in such a form that it is put around the tire when the casing is deflated and held firmly in place by blowing up the tire again. This may be classed with the tire protectors, as it is believed the heavy chrome-leather band has much more resistance to nails or other objects which might puncture the rubber tube, than the plain round-tread tire would have. At B and C devices which belong to the first class are depicted. These consist of cross chains attached i to suitable side members which encircle the wheels. The object of i the chains on the tire tread is to eliminate loss-power effort by pro- viding a better grip between the wheels and road surface, and not to act as a protector for the outer casing except in a somewhat limited way. In the form shown at B the cross chains are attached in such a manner that they lie in the same plane as do the rungs of a ladder. At (' the chain members are of zigzag form. The protectors shown I at D, E, and P are very similar in principle to that outlined at A, except that the method of securing them to the wheel varies to a ; slight extent. That at D is a form designed to encircle the casing i and can be held in place by the air pressure inside of the tire. At E the protector is fastened to the wheel by a series of strap members which clinch under a side-retaining ring member. At F the edges I of the protector are provided with hooks which grip the flanges of i the clincher tire and thus hold the protector very firmly in place i when the tire is properly inflated and the casing distended. The disadvantage of tire protectors is that they decrease the ' resiliency of the tire, because leather is not as flexible as rubber, i-s|'( -ially after it has become hard by exposure to water. The use of these protectors undoubtedly conserves the tire casing from punc- ture, but considerable heat is generated between the tire and the protector, and this may be sufficiently high to weaken the rubber < -a .-ing. Most motorists favor the use of the quick-detachable chains to prevent skidding, because these may be easily removed when they are not needed. There is some labor involved in removing and re- placing the leather protectors, and these are not usually used with new casings on account of the decrease of tire resiliency. They are often applied to weak casings or shoes which have been worn to the 608 The Modern Gasoline Automobile Fig. 314. Supplementary Treads and Anti-Skidding Attachments Designed to Use in Connection with Smooth-Tread Casings. The Modern Gasoline Automobile 609 fabric, and when used in this manner they are very useful in securing greater service from the weak tires, which would have to be discarded if some form of protecting tread was not used. The views at Fig. 315 show the ease with which Weed chain grips can be attached to the wheel. In the view shown at A the chain has been applied to the tire and the vehicle has been pushed forward just enough to ride over the loose ends of the chain, which are on the ground. At B the car has been pushed forward sufficiently so the loose ends of the chain are clear of the wheel, and the process of hooking up by means of little snap hooks is easily performed, as outlined at C. Demountable Rim Forms. The advantages of the quick - detachable rim over the ordinary clincher pattern have been previously consid- ered. It will be seen that it is possible to re- move a tire with less dif- 610 The Modern Gasoline Automobile ficulty than is present when the clincher rims are used. While a defective tire may be removed and replaced with a new one very easily, it is necessary to inflate the new tire with air by means of a hand or power pump or with carbonic-acid gas carried under pressure in a portable gas tank. In order to reduce the time occupied in changing tires, which is needed to adjust the shoe properly and blow up the inner tube, a number of demountable rims have been devised. The wheel felloe carries a metal rim, and to this is attached a second member on which the tire is mounted. The tire-carrying rim may be securely attached to the wheel by means of suitable and quickly operated clamping bolts or rims'. When demountable rims are fitted instead of carrying the usual spare outer casing, fully inflated tires are carried on rims similar to the demountable portions, and when the tire is punctured the dam- aged one and its rim are removed as a unit and a new, fully inflated member replaced. When it is necessary to remove the shoe, as in the ordinary single-rim construction, the operation of replacing a tire will take from ten to fifteen minutes under favorable condition-. but with quick-demountable rims the operation of changing a tire will take only two or three minutes. Demountable rims are more expensive than the simpler forms, but the convenience and elimina- tion of time-consuming delay, as well as the saving in labor, more than compensates for the increased cost of equipment. Numerous forms of demountable rims have been devised, but few have survived the test of time and have received general appli- cation. At Fig. 316 a combination of quick-detachable and demount- able rims is shown. With this construction the advantages of both types are obtained without disadvantages of any moment, excepting those of cost of equipment. The quick-detachable type of rim makes it possible to change the tires very easily, should this be necessary, and makes for more easy removal for repairing when the damaged tires are restored to their efficient condition. In this form the tire- carrying rim is held on the felloe band by a clamping collar mounted on the stud and forced in place by a nut on the outer end of the stud. The construction is so clearly shown that its advantages will be readily understood. The clincher type of rim has been used on many cars because it Tin' Modern Gasoline Automobile 611 has been a standard fitting for a number of years, but at the present time il is seldom used in connection with large tires, which are diflicult to remove from the wheels unless used in combination with ' a demountable rim. A number of standard demountable rims which have received general application are shown at Fig. 317. That at A holds the clincher rim which carries the tire in place by a series of clamps and wedges which are forced against the tire-carrying rim Projection on Collar Felloe-" Bolt STANDARD DEMOUNTABLE Fig. 316. Quick-Detachable Rim of the Demountable Form. by pressure of nuts carried at the end of bolts passing through the [wheel felloe and having peculiarly shaped heads, which prevent the tire-carrying rim from moving over the inner edge of the wheel. A nui iiber of these bolts are provided, the spacing varying with the weight of car and size of tire. On light cars one bolt to every two [spokes is considered ample, while on heavier vehicles a bolt may be iUsed between every two spokes, which would -mean that there would as many clamping bolts used as there were spokes Jn the wheel. The form outlined at B is similar in construction to that outlined at A. except that the felloe band is a substantial member which does not need to be reenforced to hold the tire-carrying clincher rim finnly in place when the clamps are screwed home by the nuts. The Fisk demountable rim, used in connection with the Fisk bolted-on type of detachable tire, as shown at Fig. 311, D, is outlined in section at Fig. 317, C. In this a portion of the felloe is chamfered off and 612 The Modern Gasoline Automobile 613 the felloe band is made to fit. The tire-carrying rim is locked in place by a wedge member that slides on the angular side of the felloe band when pressure is brought to bear upon its face by the nuts carried at the end of the bolts passing through the felloe and felloe band. As the wedge rides up on the incline it locks the tire-carrying rim firmly in place and prevents either lateral or circumferential displacement. In the construction depicted at D a tire-carrying rim of the clincher type is used, and this in turn is attached to' a ring member which has chamfered corners. The felloe band has two inclines, one designed to rest against one side of the chamfered ring, while the | other acts as a seat for the wedge-shape locking ring, which is forced 'in place under the tire-carrying rim by means of clamps and nuts. Jn order to make for quick removal, a wrench of the socket type is usually attached to a bit brace, such as used by carpenters, for loosen- ing and tightening and clamping nuts. With some forms of de- mountable rim it is necessary to remove the nut entirely in order to islip the clamp off the bolt. In others the nuts are merely loosened and the clamps either swung or dropped out of the way of the tire- carrying rim, which is easily slid off the felloe band. Other forms of demountable rims have been devised in which the tire-carrying member is held in place by some form of expanding bands which is jmade to increase its diameter by means of wedges or cam action, but these are not so generally used as the types described. Features of Cushion Tires. Some classes of vehicles that are not designed to run at high rates of speed, and which are not intended to ?arry heavy loads, are fitted with cushion tires. While these do not lave the resiliency of the pneumatic form, they have much greater lexibility than solid-rubber tires. For this reason they are some- inies used on the electrically propelled light delivery or pleasure .'chides and sometimes on the light-weight commercial cars of the ra-.line type. Some of the popular forms of cushion tires are shown it Fiir. 318. At A the tire tread, which is of the dual form, is molded n such a manner that a series of shallow grooves are formed around he tire. These incline from the outside toward the center and are lepended on to give improved traction as well as to make the tire nore resilient. The base of the tire is pierced with a large number 614 The Modern Gasoline Automobile of holes which extend clear through from side to side, so the outer tread or load-carrying portion is supported on a series of rubber bridges which are adapted to bend and provide a certain degree of flexibility. The cushion tire shown at B is similar in form to the conven- tional dincher casing, and is designed to be used on clincher rims Fig. 318. Cushion Tires which Provide More Resiliency than Solid-Rubber Types but are Not Equal to the Pneumatic Forms. of the pattern commonly supplied with pneumatic tires. The flexible feature of this tire is obtained by using a number of rubber load- supporting partitions to join the walls of the tire, and at the same time they are separated from each other by an air space of sufficient size so the tire will distort more easily than the conventional solid- rubber pattern.' The cushion tire shown at C depends upon the form of tread to provide resiliency, and it would not be as flexible as either of the two forms previously considered. One -objection to either solid or cushion tires is that a deep cut or stone bruise will seriously weaken the entire structure, whereas only a limited portion is really unfit for use. Then again, sometimes, when brakes are locked too suddenly, a portion of the tire may bf The Modern Gasoline Automobile 615 worn more than the other parts, but the entire efficiency of the tire will be affected and the strength will depend upon that of the weakest portion. The sectional cushion tire which is depicted at Fig. 319, A, has been evolved to make possible the replacement of one or more injured portions without disturbing the other members. The tire is composed of a series of hollow rubber segments, as shown, which Hollow Rubber Segments Solid Rubber Tread Washers / Wooden Felloe Steel Kim ?ig. 319. Novel Forms of Cushion Tires. A Cairns Detachable Segment Construction. B Combination Form Comprising Heavy Tread and In- flatable Inner Tube. are held securely in place by means of a dovetail structure which extends from the face of one segment to engage with a corresponding uember on one of the faces of the neighboring segment. These are ely fastened to the wooden felloe of the wheel and into the steel im by means of bolts and washers. A certain amount of air is Drained in the spherical chambers of the rubber segment by the seal- >ct of a special washer, and this provides an air cushion which - for easier riding than would be possible with a solid tire. In vent of damage to one segment it may be removed without difficulty ml a new one substituted. A combination cushion tire composed of a heavy solid-rubber iread and an inner tube inflated with air to form a cushion is shown t Fiir. 310, B. It is claimed for this construction that the resiliency I not greatly diminished and that the tire is absolutely puncture roof. The tire consists of two main parts, the solid-rubber outer 616 The Modern Gasoline Automobile tread being of rubber composition and mounted on a base of fabric and rubber, and the air tube, which is inflated and which provides the resilient effect. Both members are firmly clamped between cir- cumferential steel flange side rings. The inner tube rests upon an ordinary steel rim or bonding member attached to the felloe, which is made wider than the usual construction and of channel form. The steel flanges are extended beyond the rim 1 and are turned over at their outer edge in such a way that they form grooves to hold the beads of the tire, and continue to the base of rubber tread, where they end in a bead and leave sufficient space between them for the solid tread to work up and down. One of the flanges is permanently fastened to the felloe, while the other is removable by unscrewing the clamping nuts. It is claimed that as the flanges enclose the air tube as well as the weaker portions of the outer member which are subjected to the air pressure, a very strong construction is obtained. The solid- rubber tread is the only portion that comes in contact with the road, and provision is made to prevent the air tubes being chafed by the sides of the steel rim or by the edges of the outer member. When the solid tread encounters an obstacle in the road it is pressed inward against the air tube in the same manner as the conventional form of outer shoe is, and more resiliency is obtained than with the rigid solid form. The inner tube is well protected from puncture, and it is also claimed that blow-outs are almost impossible, because to reach the inner tube it would be necessary to pierce either the heavy solid tread or one of the steel side flanges. Forms of Solid-Rubber Tires. On heavy commercial vehicles it is not practical to use pneumatic tires because these would have to be of very large size to carry the loads imposed by the usual heavy truck chassis and loaded body. As the speeds of these vehicles are not very high, solid-rubber tires may be employed to advantage. These are molded from special rubber compositions in one continuous ring, and they are usually provided with some form of metal reinforcement at the bottom which insures that they will clamp tightly against the rim or the felloe band. Various forms of quick-detachable rims have been evolved to hold these members in place, and the metal reinforcements at the bottom vary from simple transverse wires to The Modern Gasoline Automobile 617 continuous bands of steel molded integral at the base of the rubber rings. A number of .solid tires and methods of attachment are clearly shown at Fig. 320. Single tires of this form are used on the front wheels of practically all trucks, though the rear members are gen- erally supplied with dual tires, which have greater carrying capacity and which also lessen the dangers of side slip on wet pavements. GOODYEAR FLANGED TYPE MOTZ FLANGED TYPE Fig. 320. Outlining Construction and Methods of Fastening Solid-Rubber Tires to Wheels. "When twin tires are used it is desirable that they be installed in such a way that they can be readily removed from the wheel for replace- ment in event of wear, and it is also thought necessary to provide means of attachment of such nature that they can be removed inde- prmk-ntly, if desired. Various dual tire forms and the method of holding them in place are shown at Fig. 321. The construction out- lined at Fig. 322 shows the application of wedges to lock the solid- ruhhcr tires firmly to the wheel. When solid-rubber tires were first applied to trucks they were of such form that special machinery was needed to install them, and the 618 The Modern Gasoline Automobile 619 work could only be done at depots where this form of machinery formed part of the equipment. When accident to the tire or natural woar made it necessary to replace the worn member with a new one the wheel had to be removed from the truck and sent to the tire company's station to be fitted up with tires. This meant a loss of Fig. 322. Hartford Detachable Twin Solid-Tire Construction. time of some magnitude, which has been entirely overcome by the new demountable construction. Spare tires may be carried in stock and may be used to replace the damaged members without the use of special applying machinery in most instances and without necessitat- ing the removal of the wheel. Tools and Supplies for Pneumatic Tire Restoration. It has been previously stated that one of the chief disadvantages of pneumatic tires has been their liability of failure by puncturing the outer casing and penetrating the inner tube and thus providing a means for escape of the compressed air in the inner tube. The life of a pneumatic iiiv is decidedly uncertain and will depend on many factors outside of those of purely natural wear. There have been cases where outer casings have given satisfactory service for seven or eight thousand miles, but these instances have been the exception rather than the rule. It is the opinion of most motorists who have had practical experience that if an ordinary set of shoes will give a service averag- 620 The Modern Gasoline Automobile e upon ing two thousand miles that they are equal to the demands made them and that they are satisfactory. It may be stated that tires will last longer on light cars than heavy ones and the service obtained from tires fitted to vehicles driven at low and moderate speeds will Air Pump Outer Casing Jack Pressure Gauge Value Tool Casing -Security Bolts Fig. 323. Spare Parts and Necessary Repair Equipment for Automobiles Using Pneumatic Tires. The Modern Gasoline Automobile 621 be much, greater than that obtained from tires fitted to high-speed vehicles. There is also a personal element which must be taken into consideration, and tliat is the way that the car is driven and the care taken of the shoes and inner tubes. Fig. 324. Forms of Tire Irons Used in Removing and Repairing Clincher Shoes. It is necessary, therefore, in all cars using pneumatic tires to carry a certain amount of equipment for handling and repairing these on the road. A typical outfit is shown at Fig. 323, this con- sisting of a spare outer casing, two extra inner tubes for replacement purposes, a blow-out sleeve, a number of patches, and an acid-cure vulcanizing outfit for applying them. Tire irons must be provided to remove the casing from the rim ; the jack is used to raise the wheel of the vehicle on which the defective tire is installed from the ground and make it possible to remove the tire completely from the wheel. The air pump is needed to inflate the repaired tube or the new mem- ber inserted to take its place. The talcum powder is sprinkled be- tween the casing and the tube to prevent chafing or heating, while the spare valves and valve tool will be found useful in event of dam- age to that important component of the inner tube. As it is desirable to inflate the tires to a certain definite pressure, a small gauge which will show the amount of compression in the tire is useful. The outfit shown may be supplemented by other forms of vulcan- izing sets and by special tire irons to make for easier removal of the 622 The Modern Gasoline Automobile outer casing. Tire irons vary in design, and most makers of tires provide levers for manipulating the casings, which differ to some extent. A set of tire irons such as would be needed with a clincher- tire equipment could be selected from the forms shown at Fig. 324. That shown at A is utilized to loosen the clincher bead from under the rim should it become rusted in place. After the shoe has been loosened from the rim flange one of the levers of the form shown at B, C, or D would be inserted under the bead in order to lift it over the rim. Two or more of these levers are provided, and the length and form will vary with the preference of the motorist. It will be remembered that the longer levers are more easily operated than the short ones, and that the length of the lever provided will depend entirely upon the size of the tire to be removed. Fig. 325. Small Repair Kit Containing Necessary Tools and Supplies for Erne gency Repairs. Motorists, as a rule, should carry the releasing lever shown at A, two of the short members depicted at B, and one longer lever, such as the upper one of group C, or the forms D or E. The latter is a I The Modern Gasoline Automobile 623 combination form which may be used as a jack handle as well as a tire iron, and when it is supplied it is not necessary to carry a jack handle in the equipment. The flattened ends are generally employed for prying the bead from the clincher rim, and when this has been Knife Clamps Roller Fig. 326. Tools Found Useful when Repairing Inner Tubes. done and sufficient space exists between the bead and the rim to insert the curved end of the larger levers, considerable leverage is obtained and the bead may be lifted over the clincher rim without undue Lamp Molds Fig. 327. Portable Vulcanizer Outfit for Filling Cuts in Outer Casings or Patch- ing Inner Tubes. 624 The Modern Gasoline Automobile exertion. The object of rounding the corners, and of making the working portions as broad as possible, is to reduce the liability of pinching the inner tube, which would be present if the irons had sharp edges. The tire-repair material is sometimes carried in a special case, as shown at Fig. 325, this consisting of all parts necessary to make temporary repairs to be considered in proper sequence. This outfit is sometimes supplemented by the special tools shown at Fig. 326. The knife is used to cut the rubber, trim patches, etc. The stitcher and roller are useful in rolling the patch after it has been cemented Fig. 328. Acid-Cure Vulcanizing Outfit. to the tire to insure adhesion of the patch with the tube, while the wooden clamps are useful in binding the patch firmly against the damaged portion of the tube while the cement is drying. Some motorists carry small vulcanizers in order to effect more perma- nent repairs than would be possible with the simple patching proc- esses in which the adhesive powers of cement are utilized. A simple steam vulcanizer and molds for use in connection with it are shown at Fig. 327, and an acid-cure vulcanizing set which does not make use of any form of heating apparatus is shown at Fig. 328. The Modern Gasoline Automobile 625 Tire-Manipulation Hints. In removing or replacing outer casings consider;! lik- i-are must be exercised not to injure the shoe or pinch the inner tube. The first step is to jack up the wheel from which the defective tire is to be removed, this relieving the wheel of the car weight. The valve inside is then unscrewed in order to allow any air that may remain in the tube to escape, and then the lock nuts on the valve stem and security bolts are removed so that these members may be lifted to release the clincher beads from the rim channels. If the tire is stiff or has not been removed for some /tdjustable Hinged Portion Flat End Fig. 329. Special Appliance for Loosening Clincher Shoes from Rim of Wheel. time, a special iron, such as depicted at Fig. 329, is utilized in the manner shown, and the beads are pushed clear of the clincher rim. When the casing has been loosened on one side, a flat tool, such as shown at Fig. 324, B, is inserted under the loose bead to act as a pry or lever to work the edge of the casing gradually over the rim. Very long levers are necessary to handle heavy, stiff tires, and new casings are particularly hard to remove. The shorter irons may be employed on the smaller casings and on shoes which have been used 626 The Modern Gasoline Automobile for some time and which are more pliable than the new ones. Two of the levers are generally used together, one being kept under the loosened edge of the bead, while the other is used to force the bead over the edge of the rim. When the outside edge of the bead has been forced over the rim at all points the inner tube is lifted from the rim and is pulled out of the shoe. The start at removing is made at the point diametrically opposite the valve stem. When this portion has been pulled clear of the rim and out of the casing it is not difficult to pull the rest of the tube out and finally lift the valve stem out of the hole through which it passes in the wheel felloe, and take the inner tube entirely off the wheel. If the casing demands attention, or if a new case is to be used, the inside bead is worked over the channel of the clincher rim in just tHe same manner as was done with the outside bead, and after a start has been made and a portion of the inside bead forced over the rim there will be no difficulty in slipping the entire shoe from the wheel. Applying a tire is just the reverse to removing one. The first operation is to place the inner bead of the tire in position in the center of the rim by forcing it over the outside flange. This is done gradually, and in order to force the remaining portion of the shoe it may be necessary to use long levers when the greater part of the casing has been applied. The next step is to work the shoe gradually toward the inner channel of the rim, then to insert the security bolts in the holes made to receive them. The inner tube is replaced after it has been partially inflated by putting the valve stem in first and then inserting the rest of the tube, being careful not to pinch it under the heads of the lugs or security bolts. After the inner tube has been put in place the outer bead of the tire is worked over the edge of the rim, the portion adjacent to the valve stem being inserted first. When working the remainder of the bead over the rim channel much care must be ex cised to insure that the inner tube will not be pinched by the shai edges of the tire levers. The object of partially inflating the inn( tube is to distend it so there are no loose or flabby portions that liable to catch under the tire bead when this is being forced in plac over the wheel rim. The mechanically fastened tires are much easier to remove thi The Modern Gasoline Automobile 627 clincher shoes, because after the retaining rims are taken off the wheels, the outer casings can usually be pulled right off the flat rim. The tools and the manner of using them employed in taking off Fisk bolted-on tires are shown at Fig. 330. The clamp is employed when replacing the shoe and it serves to hold the retaining ring and Fig. 330. Tools for Removing Fisk " Bolted On " Casings and Method of Using Them. the bottom of the shoe closed in such a way that the nuts on the through holts may be easily tightened up by using a socket wrench depicted at A. This wrench has a T handle with a hook end, and this hook is sometimes of value in prying off a retaining ring that has become rusted in place. The method of handling these tools and this type of tire are so clearly shown that further description -'i 'ins unnecessary. Tire-removing tools are made in many forms, and more have been devised for use with clincher type of casings than the other forms because the beads on these casings sometimes become so firmly imbedded in the rim channels that it is extremely difficult to remove them, especially if the shoe has been on the rim for some time. An- other form of removing tool possessing a certain amount of adjuster 628 The Modern Gasoline Automobile bility which makes it adaptable for use in connection with varying sizes of clincher casings, and the method of use, is shown at Fig. 331. In this form the main or handle portion has a piece extending from it that carries a rubber roll designed to pull against the spoke. The part that bears against the shoe is a separate piece, provided with a number of hooks to make it possible to alter its position as desired. For use with a small tube the uppermost notch is used, and as the shoes become larger the notched piece is pulled farther up in the slot in which it slides on the head of the Y-shaped handle. Tools of this nature are extremely useful and should form part of the equip- men of every motorist who uses clincher tires. Fig. 331. Adjustable Iron for Loosening Clincher Casings That Have Stuck Rims. Rules for Tire Selection and Inflation. The tires used on motor cars are generally selected by considering the amount of load si tained by the wheels of the cars, but considerable difference of opin- ion seems to obtain regarding the way the weights should be esti- mated. Tire manufacturers believe that the entire weight of th vehicle with all possible equipment and passengers must be con- The Modern Gasoline Automobile 629 -i'K'ivd. but there have been cases where a car has been supplied with tires that were inadequate because only the weight of the car was considered in making the selection and the added load of passengers and equipment was disregarded. It is believed desirable to provide rear tires that will be twenty-five per cent larger than those needed merely to support the weight of the rear end of the vehicle, because in the majority of cases these members are called upon to sustain stresses incidental to traction as well as the strains produced by the vehicle weight. It is customary to use one size tire on the four wheels, the thought being that the shoes from the front wheels, which are not subjected to the severe service that those on the rear are called upon to endure, can be placed on the rear wheels when those casings be- come weakened by use, and their place taken by the weakened rear shoe, which may have sufficient capacity to do the work expected of front-wheel tires. The following table gives the proportion between vehicle weights and tire sizes that are commonly accepted by tire manufacturers. These figures are based on the maximum permissible weight of a car without passengers, but as they do not consider the factor of possibilities of overload,, and if a motorist is having tir& PROPORTIONS BETWEEN AXLE LOADS AND TIRE SIZES ADOPTED BY AMERICAN TIRE MAKERS tires, all diameters .............. 225 pounds per wheel 3 inch tires, all diameters .............. 350 " 3^ x 28-inch tires ....................... 400 " 3% x 30-inch tires ....................... 450 " 3 Ji x 32-inch tires ....................... 555 " 3i/3 x 34-inch tires ....................... 600 " 3^ x 36-inch tires ....................... 600 " 4 x 30-inch tires ....................... 550 " 4 x 32-inch tires ....................... 650 " 4 x 34-inch tires ....................... 700 " 4 x 36-inch tires ....................... 750 " 4% x 32-inch tires ....................... 700 " Y 2 x 34-inch tires ....................... 800 " V/2 x 36-inch tires ....................... 900 " For weights in excess of 1,000 pounds per wheel, 5-inch tires and over are recommended. Weights given apply to car without passengers. 630 The Modern Gasoline Automobile troubles, it would be well to provide tires that are oversize and of more than sufficient capacity. Such members are not only more enduring than shoes which are barely up to the requirements, but they are not liable to blow out or deteriorate as fast as overloaded tires. Next to the selection of proper size tires the important con- sideration is that these be kept properly inflated. If a tire is not properly filled with air it will flatten out, and the tendency will be to separate the layers of fabric and rubber of which the shoe is com- posed, because of the alteration of the almost round or tubular section that the tire is supposed to be when in use. If a tire is properly inflated the walls will be braced from inside by the pressure of the compressed air in the inner tube, and the flattening effect will have no perceptible effect in producing disintegration of the fabric and rubber plies of the casing. The figures given in tables which follow are those recommended by leading tire manufacturers as being most suitable for the various sizes of tires listed. These usually take into account the increase in temperature and resulting pressure of the air created by the friction between the tires and Tfoe roads caused by prolonged running. A French authority has made a series of tests to determine what the increase of pressure would be on tires from three to four and a half inches in diameter under usual touring-car service conditions. These results are pre- sented in tabular form and should prove very interesting. The in- crease with larger tires is greater in proportion because the walls of the casings are heavier and stiffer and greater internal strains are produced in the fabric by the distortion of the shoe at the points of bending. AIR PRESSURES FOR INFLATING PNEUMATIC TIRES RECOM- MENDED BY LEADING MAKERS Diameter of Tire, Maximum Weight on Air Pressure in Tire, Inches Wheel, Ibs. Ibs. per Square Inch 2Y 2 225 50 3 350 60 3^ 600 70 4 750 80 y?. 1,000 90 5 1,000 90 The Modern Gasoline Automobile 631 INCREASE IN AIR PRESSURES CAUSED BY DRIVING INITIAL PRESSUKE IN TIRE, COLD WORKING PRESSURE IN TIRE, WARM INCREASE RESULTING FROM WORK Lbs. JUT Sg. In. Lbs. per Sq. In. Lbs. per Sq. In. 71.116 88.183 17.067 85.339 105 . 750 20.411 99.562 123.546 23.984 113.785 141.920 28.135 128.008 158.588 . 30.580 142.232 176.368 34.136 The conventional method of inflating tires by using a foot pump docs not always insure that the tire will receive adequate inflation, and when a pump is employed it is imperative that some form of gauge be provided that will register the amount of pressure inside of the tire in order that it will reach the figure recommended by I the tire makers. Different methods of tire inflation have been de- vised which eliminate the necessity of using manually operated pumps. obviously a simple expedient would be to provide a small power- driven pump that could be actuated by any convenient mechanical con- . nection with the engine. Another method is to use an air bottle, which is a steel container in which air is stored under great pressure. Tin air is compressed to such a point that a tank less than two feet Ion- and six inches in diameter will furnish sufficient air to in- | flate seven or eight tires of average size, or twelve to fourteen small ones. The tanks may be exchanged at small expense when exhausted for new containers holding a fresh supply of air. In some tanks gases of various kinds under high pressure are used iind the motorist may obtain these on the same basis as air bottles are supplied. All devices of this character are fitted with gauges to indicate the amount of pressure in the tire, and to prevent overinflation. If a tire is not properly inflated the shoe will be liable to various kinds of road damage and will be easily punctured, while if the pressure is too high the shoe is liable to "blow-out" at any weak point in the -nurture. A tire-pressure gauge is a very necessary article of equip- ment in any car and its proper use when blowing up tires will insure 632 The Modern Gasoline Automobile the best possible results if the schedule recommended by the tire manufacturers is adhered to. Tire Repair and Maintenance. The common causes of tire failure that the motorist is apt to encounter are shown at Fig. 332. The Stone Bruise Sand Blister Leaky Valv Worn Tread A^ Chafed Side Fig. 332. Sectional View of Pneumatic Tire Showing Some Conditions Which Cause Failure. I The Modern Gasoline Automobile 633 most common is natural wear of the tread portion of the tire. The rubber compound in contact with the road surface wears away in time, and the fabric layers which constitute the breaker strips are exposed. The shoe is weakened and any sharp object in the road is apt to penetrate the weakened case and puncture the inner tube. If a num- ber of the layers of fabric comprising the body of the shoe are cut this constitutes a weak place in the casing and a blow-out will result because the few layers of fabric remaining do not have sufficient strength to resist the air pressure. A stone bruise is caused by the removal of a portion of the rubber tread by a sharp stone, piece of glass, etc., and is much more serious than a puncture because it removes some of the tire, whereas in ordi- nary cases of puncture a sharp object merely penetrates the casing. A sand blister is produced by sand or grit from the road working into a space in the tire between the tread and the fabric body through some neglected incision or bruise. The side of the tread is often chafed by running the tires against curb stones or by driving in car tracks. Rim cutting is generally caused by insufficient inflation which permits the rim to cut into the tire and thus tends to sever the bead from the side of the shoe. The chief inner tube trouble is penetration of the wall by some sharp object, or the folding over of part of the tube walls when the tire was applied. The parts of the check valve sometimes give trouble and the valve leaks. In cases of valve trouble it is usually cheaper to replace the valve inside than it is to attempt to fix it. Some of the causes of valve leakage are hardening of the rubber washer, bent stem, which prevents the valve from seating properly or a particle of dust or other foreign matter which would act to keep the valve from closing the air passage positively. The most serious condition that a motorist will meet with is a " blow-out " and usually only temporary repairs can be made on the road. The common methods of restoring a defective outer casing are depicted at Fig. 333. In this an inner sleeve, which is composed of a number of plies of fabric, is placed between the inner tube and the broken portion of the outer casing to prevent pinching of the inner tube by the jagged edges of the cut, and to strengthen the casing from the outside an outer shoe or gaiter made of leather is laced around 634 The Modern Gasoline Automobile the shoe. The object of using both inside and outside reenforcing members in combination is to not only strengthen the weak outer casing but by providing an outer shoe dirt is kept from working into the tire. Punctured inner tubes may be temporarily repaired by using a cemented surface patch. The first step necessary is to clean the surface of the tube very thoroughly with gasoline and then to rough up the surface of both patch and portion of the tube surrounding the 'read in Casing .Outer Casing inner Sleeve with Hooks Fig. 333. Temporary Casing Repairs Possible When Small Blow-Out or Large Puncture Occurs on the Road. holes with a wire scratch brush or with sandpaper. After the sur- faces are properly cleaned and roughened the patch and the tube are coated with suitable patching cement which is alLowed to become thoroughly dry before the second coat is applied. The second coat is allowed to become " tacky," which expresses a condition where the cement is almost dry and yet still possesses a certain degree of ad- hesiveness. The patch is applied to the cemented portion of the tube and the whole is clamped firmly together to secure positive adhesion The Modern Gasoline Automobile 635 while the cementing medium is drying. Patches should always be of suilu-ient size to cover the damaged portion and at the same time have about three quarters of an inch or more of the patch at all sides of the orifice. Very satisfactory repairs to both inner tubes and outer casings of a permanent nature can be made by using small portable vulcanizers which may be heated by either electricity or vapor. AVhen these are used a special vulcanizing cement is necessary and uncured rubber stork must be used for patching or filling openings, caused by punc- tures or blow-outs. The patch of raw material is applied to the cemented surface of the tube or casing and the vulcanizer heated to the proper temperature. The heat of the vulcanizer causes the rub- ber of the patch to unite perfectly with the old material and forms an intimate bond. In vulcanizing the most important precaution is to maintain a proper temperature. Too great a degree of heat will burn the rub- ber, while a proper cure cannot be effected if the temperature is too low. The temperatures recommended for vulcanizing vary from 250 to 375 degrees F. The lower degree of heat is used in working ma- terial that has been previously cured, while the higher temperature is recommended for new rubber. A number of small portable vulcan- ic rs and their method of use is shown at Fig. 334. In the view at A the vulcanizer is heated by electric current and is provided with two faces, one flat, designed for use against inner tubes, and the other curved to conform to the curvature of outer casings. In the view A the vulcanizer is shown with the flat face in use, while at B it is shown clamped to an outer casing with the curved face in contact with the tread. The heat is obtained by passing a current of elec- tricity through suitable resistance coils imbedded in the body of the device. Where electric current is not available various forms of flame- heated vulcanizers may be used. In that form depicted at C the vulcanizer body is filled with water, which is converted into steam by the heat of a flame furnished by the alcohol lamp that forms part of the device. This form of vulcanizer is provided with a flat face as well as a curved one and can be used for either inner tube or outer casing restoration. A combination vulcanizer which is composed of 636 The Modern Gasoline Automobile a large hollow cast-iron body filled with water and heated with spirit lamp is depicted at D. In this the curved face and the flat Curved Face in Use Flat Face in Use Clamp Curved Face in Use eter Flat Face in Lamp Clamp Curved Face in Use Fig. 334. Methods of Using Small Electric or Vapor Vulcanizers on Tut and Casing Work, a Very Convenient Method of Effecting Permanent pairs. The Modern Gasoline Automobile 637 face may be used simultaneously and an inner' tube patched at the same time that the outer casing is being treated. As very complete instructions are furnished with these small vulcanizers, any motorist may become familiar with their use without much difficulty. In describing the methods of removing clincher casings special emphasis was laid on the necessity of careful manipulation to prevent pinching of the inner tube. The manner in which this somewhat Fig. 336. How Inner Tubes May Be Pinched and Ruptured if Outer Casing is Replaced Carelessly or if Tire Lugs Are Not Properly Placed. delicate member may be ruptured when applying or removing outer casings may be easily understood by reference to Fig. 335. At A the inner tube is pinched by a poorly fitting bead which does not bed properly into the channel of the rim. At B a portion of the inner tube has been caught under the bead of the shoe when this was applied because the tube was not properly inflated before it was inserted into 638 The Modern Gasoline Automobile the casing. At C and D the inner tube has been pinched by care- lessly placed or poorly fitting security bolt. The rules to secure satisfactory operation from pneumatic tires may be easily summed up. In the first place it is imperative that the tires be inflated to the pressures recommended by the manufac- turers and that they be selected with a certain margin of safety over the actual requirements. The tires should be kept clean and free from oil or grease because the oleaginous substances used for lubri- cation very quickly attack rubber compounds and cause crumbling and rapid deterioration. Oil or grease should be wiped off as soon as noticed and the tire cleaned by the application of gasoline. Any small cuts or openings in the tire that may permit water to enter or sand to work between the fabric and the tread will cause trouble in time. One should be careful in driving not to apply the brakes too suddenly because this will lock the wheels and wear the tire very quickly. Care should be taken not to drive in car tracks, and when highways do not have the proper surface they should be negotiated very carefully to avoid cutting the casings. Advantages of Detachable Wheels. Detachable wheels may be either of the wire wheel pattern or of the artillery construction. In all forms of detachable wheels two hubs are necessary : an inner mem- ber, which is in permanent assembly with the axle, and a removable outer member to which the spokes and rims are attached. In the Budge-Whitworth construction, shown at Fig. 335a, the steel shell to which the spokes are laced is readily removable from the inner mem- ber or hub casting proper. The object of this construction is to per- mit the motorist to carry a spare wheel with a fully inflated tire, so that in event of puncture or blowout it is possible to remove the entire detachable wheel assembly affected and replace it with the spare member carrying the fully inflated tire which has been provided for replacement purposes. All detachable wheels are constructed so that they may be readily removed from the inner hub member, and the entire wheel assembly may be replaced much easier and quicker than replacing the ordinary form of tire. Another quality of some importance is the ability of the wire wheel with the spokes laced tangent, to absorb the shock or starting Tlic Modern Gasoline Automobile 639 ~ffot//t TTreRtng Speedometer Sprocket Fig. 335a. Sectional View Showing Construction of Triple-Spoke Rudge- Whit- worth Detachable Wire Wheel. 640 The Modern Gasoline Automobile or sudden application of power in the plane in which the wheel rotates. This quality is absent in wooden wheel construction. It is a well-known fact that the friction between tire and road generated in driving a car at even a reasonable speed results in quick and excessive heating of the tire structure. In the wooden wheel, which serves in a sense as insulation, there is a very slight ability to quickly dissipate heat. Wire wheels requiring only a thin metallic rim, the spokes serving in a sense as cooling flanges, will dissipate this heat almost as quickly as it is generated. This results in keep- ing the tire at almost normal temperature even in very warm weather. &&&& jy Fig. 336b. Principal Types of Anti-Friction Bearings that have been Used in Automobile Work. The Modern Gasoline Automobile 641 Ball and Roller Bearings. The plain bearings which have received wide application in all forms of machinery are not as popular in auto- mobile construction, because in the self-propelling mechanism it is important that the power generated by the motor should be delivered to the traction members with as little loss as possible. Plain bearings consume considerably more power than do the anti-friction types, and because of this, the latter are employed generally throughout the power transmission system and wheels of all types of cars, while they have replaced the plain bearings used on motor crankshafts to some extent as well. Anti-friction bearings are those in which rolling fric- tion is substituted for sliding friction and consume from one-fourth to one-eighth as much power as plain bearing forms of equivalent capacity. All anti-friction bearings may be divided in two general classes, those employing balls to carry the load, as shown at A and 5, Fig. 3356, and the other types depicted at C and D, which utilize rollers. The ball bearing depicted at A is cup and cone form patterned some- what after bearings that have received wide application in bicycles and numerous other light machines. This bearing has an angular contact, and is capable of taking radial and thrust loads. A radial load is one applied at a right angle to the centre line of the shaft passing through the bearing cone, while an end thrust is a load that tends to push the cone laterally against the cup. An angular resultant is a load composed of a combination of end thrust and radial stress. A ball or roller bearing having angular line of contact is suited to resist either a radial or thrust load or a combination of the two. Angular contact bearings, or the cup and cone type, are adjustable to a certain degree, inasmuch as lost motion may be eliminated, if not due to bearing depreciation, by forcing the cup or cone into more intimate contact with the balls, providing the other member is held against a suitable shoulder in the housing or or the shaft. The ball bearing shown at B is an annular form having a vertical load line, and is thus adapted only for radial loads and very light end thrust. The roller bearing shown at C is provided with straight rolls, and can only take radial loads just as the ball bearing shown at B. The roller bearing depicted at D, which employs tapered inner and outer race members and correspondingly tapered rollers, is capable of resist- 642 The Modern Gasoline Automobile ing end thrust as well as radial loads, but as is true of the cup and cone bearing depicted at A, the direction of the load must be such that the bearing parts will be forced more closely together. If a straight roller bearing or an annular ball bearing having a vertical line of contact is used at points where considerable end thrust exists, it is necessary to apply another bearing to resist the thrust. A double row form of bearing, which consists virtually of two cup and cone bearings mounted together in a common shell, has received gen- eral application because it can take the loads applied from any direc- tion. The load lines are at an angle and diverge from the centre line of the bearing outwardly. A radial load will be resisted by both rolls of balls, while a thrust load from either direction will be sustained by the outer race and balls opposite the point of application, assuming that the outer race is held against an abutment or shoulder in the housing while the load is applied to the cone. The angularity of a load line of a bearing affects radial and thrust capacity, depending upon the angle the load line assumes with the horizontal or vertical centre lines of the bearing. As a bearing with a vertical load line has the greatest radial capacity and practically no resistance to end thrust, it follows that one with a horizontal load line will have the greatest thrust capacity and practically no resistance to radial loads. Eoller bearings may be made with either solid or flexible rolls. A solid roller should be short in order to prevent deflection or dis- tortion of the roll if the stress is not evenly applied. If long solid rollers are used one end will tend to travel faster than the other, and this is apt to produce friction between the rolls and the retaining cage. It is contended by adherents of the flexible roll construction shown at Fig. 335c that this type adapts itself more readily irregularities in shaft contour, and thus turns with less friction than do the solid rolls. The flexible roller bearings are made in two ij\ one employing long steel rolls, while the high duty type uses short rolls of high tensile strength alloy steel and accurately ground inn* and outer race members. In the regular or long roll pattern the shaft itself is intended to form one bearing surface, and as this is generally soft, the rolls must be long in order to distribute the load over mot surface. Flexible roller bearings are wound from strip stock, so that The Modern Gasoline Automobile 643 STXEL SLEEVE CAGE Fig. 335c. Two Types of the Hyatt Flexible Roller Bearing. right and left spirals exist in alternate rollers, and the oil will be constantly circulated from one side of the bearing to the other. In either ball or roller bearings the effect of the load is to flatten tin 1 supporting members a very small amount, so that in a roller bear- ing the contact between the roller and race-way may be represented by a rectangle having a length equal to the roll, but a width so small thai it is usually considered a line contact. In a ball bearing the flat- ti-iiiiig of the ball produces an ellipse of such small area that it is usually considered a point of contact. As the reduction of friction depends upon the amount of surface in contact, it can readily be understood that the form having the least amount of surface would 644 The Modern Gasoline Automobile Fig. 336d. Front Wheel of Heavy Truck Mounted on Double Row Bearings. have least friction. Ball bearings are generally employed where it is desirable to reduce friction to a minimum or where bearings must attain high speed. Eoller bearings have been widely applied where bearings of relatively small diameter but of large carrying capacity must be used, where the shafts revolve at a compare tively low speed, and where maximum bearing efficiency is not im- portant. The motor truck wheel shown at Fig. 335d is mounted ball bearings of the double row form, while the crankshaft of th The Modern Gasoline Automobile 645 motor depicted at Fig. 335e is supported by single row annular ball bearings. Many other examples showing the practical application of all types of anti-friction bearings will be found at various points in tliis work. Great care is needed to keep anti-friction bearings free from water or grit, and also to keep them adequately lubricated. The lubri- cant must be a pure mineral substance, and should not contain acid or animal fillers, because the highly polished surfaces of the anti- friction members and races will be roughened by etching or rusting due to chemical action, and this will interfere with smooth operation and tend to produce rapid depreciation. A heavy bodied lubricant of the semi-fluid type is best adapted for use in bearings subjected to heavy loads and revolving at low speed. Graphite greases having Fig. 335e. Sectional View of Mais Motor Truck Power Plant with Crankshaft Mounted on Ball Bearings. 646 The Modern Gasoline Automobile about the consistency of vaseline or petroleum jelly are generally aj plied for this purpose. If an anti-friction bearing is housed in oil-retaining, dust-excluding housing, it is good practice to use a medi- um grade machine oil and operate the bearings in a constant bath lubricant. Ball or roller bearings should never be driven in place or moved with a steel drift or hammer, because the races are hard st and are apt to be cracked unless they are forced in place either with steady pressure, as by an arbor press, or by blows applied throuj the medium of a block of hard wood or piece of Babbitt metal inter- posed between the hammer and the bearing. The blow should alwaj be directed or the pressure exerted against the race member that is being forced in place. CHAPTER XI Motor-Car Equipment and Accessories Air- and Gas-Operated Engine Starters Electric Starting Systems Gas- and Electric-Lighting Appliances and Their I'se Wind-Shield Forms Shock Absorbers Speedometer and Mile- age Indicators Tool Equipment for Ordinary Repairs Miscellaneous Supplies of Value to the Motorist How Supplies are Carried. COINCIDENT with the development of the motor car there has been produced a large number of accessories, some of which make for greater comfort while touring and others that have material influence on the safety of the car and its occupants. Many accessories have' been devised for application to motor cars of various classes, but many of these are not necessary and have but little real merit. In this exposition the writer will confine his remarks to tried and proven auxiliaries desirable to include in the motor-car equipment and which may really be regarded as necessary to obtain the maximum amount of pleasure and profit possible from motoring. Many of the devices listed are now supplied by manufacturers as regular equipment because they are considered as much a part of the car as some of the more important components belonging to the mechanism proper. Other devices of considerable value must be furnished by the motorist himself and when one tries to make selec- tions from the stock of the average supply house it is quite difficult to differentiate between the valuable and necessary accessories and those which are not needed unless one is guided largely by the experience of others. Self-Starters for Gasoline Engines. One of the disadvantages of the gasoline engine which has been often advanced by those favoring -tram or electric power is that it is difficult to start it in some cases, and various means were devised to overcome the objection advanced. The early gas engines fitted with poorly designed carburetors and. in- adequate ignition systems were often diilieiilt to set in motion, but as tiie gasoline engine was improved and the multiple-cylinder form 647 648 The Modern Gasoline Automobile gained in favor, those used during the past few years have been easy to start by some form of starting handle or crank and often a quarter turn of that member is sufficient to set the engine in motion if it was in proper adjustment and the various auxiliary groups were function- ing properly. At the present time the improvements made in the gasoline automobile have been more in the nature of detailed refine- ment and those engaged in producing motor cars have studied more carefully the various points which make automobiles more convenient and more easily operated. The requirements of the present day can- not be met by easy starting motors because this feature is common to all automobiles from the smallest runabout to the heaviest touring car or truck. The present demand is for engines that are equipped with -some form of mechanism which will make them self-starting, that is, so thai they may be set in motion by merely pressing a button or push- ing a valve from the seat and not by the usual form of hand crank at the front of the car. The starting handle has always been a dan- ger point and many broken arms and fractured wrists have resulted from a premature explosion of gas in the cylinders which forced the starting handle backward and against the arm or hand of the person starting the engine. Motor-car control has been simplified to a point where many women are running cars, but the average motor requires the expenditure of more strength than that possessed by the average woman or young person to start it. When a separate starting device is fitted the motor may be started as easily by a person lacking strength as by one who can " spin " the engine around at will. Self-starters operate on two principles. First, that in which tl crank shaft is rotated by some form of external mechanism whic causes the pistons to draw in a charge of gas in the usual manner and which is merely a mechanical substitute for hand cranking. Seconc those systems in which a charge of gas is supplied the cylinders anc ignited independently of crank-shaft rotation. Mechanical starter include all devices which rotate the shaft to produce the cycle of oper- ations necessary to secure the power impulse in the cylinders, anc motion may be imparted to the crank shaft in two ways : by the of independent mechanism, or by making a motor of the engine itself. The independent motor devices may be spring, air, or electrically The Modern Gasoline Automobile 649 operated mechanisms. Spring motors have not attained the popular- ity that air or electric motors have because they weigh considerable and occupy more space than would be needed by the other types. Their capacity is limited because the energy is supplied by a spring . Special Check Values Acetylene Tank Fig. 336. Simple Ignition Starting System Using Acetylene Gas and Hand-Oper- ated Distribution Valve on Dash. i or springs which become unwound and which cannot supply any i energy when they are uncoiled. Spring motors are usually geared to ! the crank shaft and thrown out of gear by automatic means after the i engine is started when the springs have been wound to the proper de- ' gree of tension. Air and electric motors have received some appli- cation, but as a general rule it is the simpler ignition starters that are the vogue. Features of Ignition Starters. It is not an uncommon thing to start a four- or six-cylinder motor by merely turning on a switch because a certain amount of unexploded gas may remain in one of the cylinders and this may be compressed to a point where it will explode* as soon as an electric spark takes place in the cylinder to fire the gas. It is natural, then, that the first starting systems proposed should incorporate some means of furnishing a charge of gas to the engine and then exploding it. The gas supplied may be either carbureted 650 The Modern Gasoline Automobile gasoline or acetylene and the conditions which exist are similar to those present when the engine is started on the spark. A simple form of gas-starting systems is outlined at Fig. 336. Special check valves are inserted in each cylinder head of the four- cylinder motor and are supplied with gas through a special form of hand-operated rotary distributor valve carried on the dash. The gas is supplied from an acetylene tank and one or two turns of the dis- tributor handle serves to supply gas to the cylinder, the piston of which is at the upper center and in the proper position to receive the impact of the exploded gas. Turning on the switch, provided that the car is a form using battery ignition as an auxiliary or regular system, will suffice to produce a spark in the cylinder to which the gas has been introduced and will start the motor. Gasoline is sometimes used as a starting medium and when this is employed some form of pump is used to force an explosive vapor into the cylinder. An upward movement of the pump handle draws in a certain amount of gasoline from the tank and air through some Center Line of Handle, when in normal position st line up with notch n Flange, Fig. 337. Ignition Starting System in which a Hand-Operated Pump Forces Mixture to Cylinders. form of special inlet check, and when the pump handle is depressed the gasoline mixture is pumped into the proper cylinder through a pipe which is attached to some form of distributor or selector valve to direct the gas stream to the proper explosion chamber.- A system which depends upon supplying gas is shown at Fig. 337. In this The Modern Gasoline Automobile 651 the hand pump is placed in front of the operator's seat in such a position that the handle may be conveniently reached by the driver <>r passenger. A couple of strokes of the pump suffices to supply enough explosive mixture to start the engine when the ignition cir- cuit is completed. The gasoline-starting system is not as popular as that using acetylene gas because the latter gas will explode easier and the operator does not need to exercise the degree of judgment that is needed when supplying a gasoline vapor. Compressed-Air Starting Systems, Two forms of air-starting sys- tems are in general use, one in which the crank shaft is turned by means of an air motor, the other class where compressed air is ad- mitted to the cylinders proper and the motor turned over because of Dash Value Control Air Gauge Connection for filling Tires Pump engaging Foot Treadle Safety Value- y\ Air s ipply Tank Fig. 338. Never-Miss Starting System with Special Air Motor for Mechanical Cranking. the air pressure acting on the pistons. A system known as the " Xever- Miss " is shown at Fig. 338. In this a small double-cylinder air pump is driven from the engine by means of suitable gearing and supplies air to a substantial container located at some convenient point on the chassis. The air is piped from the container to a dash- control valve and from this member to a peculiar form of air motor mounted near the crank shaft. The air motor consists of a piston to 652 The Modern Gasoline Automobile which a rack is fastened which engages a gear mounted on the crank shaft provided with some form of ratchet clutch to permit it to revolve only in one .direction, and then only when the gear is turning faster than the engine crank shaft. The method of operation is extremely simple, the dash-control valve admitting air from the supply tank to the top of the pump cylinder. When in the position shown in cut the air pressure will force the piston and rack down and set the engine in motion. The Special Cylinder Control Valve* Connection for Tire Inflator Fig. 339. Janney-Steinmetz Compressed-Air Starting System. valve is a special form and the piping is arranged in such a manner that a current of air may be sent against the bottom of the piston when it has reached the end .of its stroke to return it to the top of the pump cylinder. When the piston reaches the bottom of its stroke, the air is automatically discharged through a series of exhaust open- ings in the cylinder wall. An air gauge is placed on the dash so that the pressure of air in the supply tank may be ascertained at a glance. If the pressure is lower than it should be a foot treadle is depressed and the air pump put into action by meshing the driven gear on the pump crank shaft with the driving member that supplies power from the engine. When the air pressure is sufficiently high the treadle is released and the I The Modern Gasoline Automobile 653 pump ceases to supply air. A safety valve is installed on the tank to relieve any excess pressure which might accumulate if the pump is kept in action longer than needed. Another form of air-starting system in which air is supplied di- rectly to the cylinders of the motor through a special distributor ar- rangement is shown at Fig. 339. The small air pump is driven by gear connection from the engine in the usual manner, and supplies air to a pressure tank. The distributor is driven in much the same manner and at the same speed as an ignition distributor used on a magneto, and the arrangement of piping is such that the air is Fig. 340. Parts of Air-Starting Group Supplied on Chalmers Cars. A Pressure- Supply Valve. B Compressed Gas Tank. C Dash Starting Button. D Mechanical Distributor. E Cylinder Check Valves. F Gas Shut-Off. G Pressure Gauge on Dash. H and I Air Connection for Tire Inflation. supplied to the cylinders in the regular firing order. When the foot valve is depressed air is admitted to the cylinders and the engine is kept in motion by air pressure until it has inspired a charge of gas which becomes ignited and starts the motor on its cycle of operation. The starter used on the Chalmers car and fitted to the car as an integral part of the power plant is shown at Fig. 340. In this a check valve in the head of Number 1 cylinder stores air under pressure in a tank carried in the body of the car. A dash valve re- leases air from the tank when it is desired to start the motor and this is carried to a distributor operating upon the same principles as the 654 The Modern Gasoline Automobile usual form of ignition commutator. The compressed air is sent to the cylinders which are ready for firing and in this way the motor is operated and the crank shaft turned by the air pressure until sufficient gas has been drawn in from the carburetor by the downwardly moving piston to make ignition effective. One of the disadvantages of the air-starting system shown at Figs. 339 and 340 is that these are not effective if the motor should stop on dead center, i. e., when the piston in the working cylinder is exactly at the top of its stroke. This condition is one that seldom obtains in a gasoline engine because the natural tendency is for the pistons to balance themselves in such a way that they are nearer the middle of their stroke than the dead center position. Should a motor stop on dead center it may be easily turned over a small amount by the hand crank and then the self-starting device immediately becomes operative. One of the ad- vantages of these systems is that they furnish air for tire inflation as well as for motor-starting purposes. When used on a six-cylinder engine the objection advanced that the motor is liable to stop on dead center is not to be considered as with a four-cylinder motor. Electric Starting Systems. Starters utilizing electric motors to turn over the engine have been recently developed, and when properly made and maintained in an efficient condition they answer all the requirements of an ideal starting device. The capacity is very high, as the motor may draw current from a storage battery and keep the engine turning over for half an hour on a charge. The objection against their use is that it requires considerable complicated and costly apparatus which is difficult to understand and "which requires the services of an expert electrician to repair should it get out of order. A typical electric starter, such as used on the Cadillac car, is out- lined at Fig. 341. The apparatus necessary consists of some source of electric-current supply, means for storing electricity, and some method of applying the power to rotate the engine. In the Cadillac system the electric current is generated by a combined motor genera- tor permanently geared to the engine. When the motor is running it turns the armature and the motor generator is acting as a dynamo, only supplying current to a storage battery. On account of the vary- ing speeds of the generator, which are due to the fluctuation in engine speed, some form of automatic switch which will disconnect the gener- The Modern Gasoline Automobile 655 ator from the batter}" at such times that the motor speed is not sutliciently high to generate a current stronger than that delivered by the battery is needed. These automatic switches are the only delicate part of the entire apparatus, and while they require very delicate adjustment they seem to perform very satisfactorily in practice. Magneto^ Distributor Distributor Coil ~ Motor Generator Fig. 341. Motor Generator Employed in Starting Cadillac Motor also Furnishes Current for Ignition and Lighting. When it is desired to start the engine an electrical connection is established between the storage battery and the motor-generator unit, and this acts as a motor and turns the engine over by suitable gearing which engages the gear teeth cut into the engine fly wheel. On the Cadillac car the motor generator furnishes current for ignition and lighting as well as for starting the motor, and the fact that the current can be used for this work as well as starting justifies to a certain extent the rather complicated mechanism which forms a complete starting, lighting, and ignition system. 656 The Modern Gasoline Automobile The Modern Gasoline Automobile 657 Electric Starting Systems for 1914. Electric starting systems may be divided into a number of distinct types, as shown at Fig. ;ll'/. It may be a single-unit system, as shown at A, in which a single generator also acts as a starting motor and igniter. The sys- tem shown at B is a two-unit system in which the mechanical gen- erator also serves for ignition, but delivers its energy to the crankshaft by means of a separate motor. Another two-unit system is outlined at ('. Here a conventional high-tension magneto is fitted for igni- tion and the combined starting motor and current-generating unit form a separate appliance. A three-unit system, which is the most popular, is outlined at D. Here a mechanical generator is used solely for charging a storage battery, a high-tension magneto of the regular form is depended on for ignition, while the motor flywheel is rotat- ing by a separate electric motor. geared to it. There are approxi- mately nineteen or twenty three-unit systems on the market at the present time, all of which differ only in points of minor detail. There are but twelve two-unit systems and three one-unit systems. An electric generator and motor do not complete a self-starting system, because some reservoir or container for electric current must be provided. The current from the generator is usually stored in a storage battery from which it can be made to return to the motor or to the same armature that produced it. The fundamental units of a self-starting system, therefore, are a generator to produce the elec- tricity, a storage battery to serve as a reservoir, and an electric motor to rotate the motor crank shaft. Generators are usually driven by enclosed gearing, though silent chains are used where the center distance between the motor shaft and generator shaft is too great for the gears. An electric starter may be directly connected to the gaso- line engine, as is the case where the combined motor-generator replaces the flywheel. The motor may also drive the engine by means of a silent chain or by direct gear reduction, as shown at Fig. 341&. Every electric starter must use a switch of some kind for start- ing purposes and most systems include an output regulator and a reverse current cutout. The output regulator is a simple device that regulates the strength of the generator current that is supplied the storage battery. A reverse current cutout is a form of check 658 The Modern Gasoline Automobile The Modern Gasoline Automobile 659 Motor Generator Replaces Flywheel Storage Battery Fig. 341c. One-Unit Starting System in which Combination Motor-Generator Replaces Engine Flywheel. 660 The Modern Gasoline Automobile valve that prevents the storage battery from discharging through the generator. A starting system of the one-unit type is shown at Fig. 341&. Here the generator not only provides current to charge the storage battery, but also may be turned into a starting motor to rotate the engine crankshaft. The storage-battery current is used for ignition purposes as well as for starting and lighting. The combined motor- generator is attached to the side of the engine base and its armature is driven by a silent chain when it is a generator, and it drives the crankshaft through suitable reduction gearing when the device is employed as a starting motor. The complete starting system shown at B, Fjg. 341c, is one in which the motor-generator replaces the gasoline engine flywheel. This means that it is directly connected to the motor crank shaft and does not employ any reduction gearing of any form. The various members comprising the starting system are indicated in heavy black lines, while the rest of the chassis is shown in light black lines. The system is simple and easily understood. An automatic switch which changes the electric machine into a generator for charging the storage battery when the gasoline engine is running and the starting button is in its released position is one of the important parts. The regu- lator which makes the rate of charging the battery the same at all engine speeds is placed on the dash. The simple operation of de- pressing the starting button when the gasoline engine is not turning changes the flywheel generator into an electric motor that draws current from the twenty-four volt storage battery and which rotates the motor crank shaft. A Jeffery motor, with unit motor-generator replacing the flywheel, is shown at A, Fig. 341c. Two-Unit Electric Motor Starting System. The application of a very effective two-unit starting s}'stem employed on the Haynes car is shoAvn at Fig. 341<1 The generator is attached to the right side of the motor crank case and is driven from the timing gear case by positive mechanical connection. The location of the generator in relation to the other portions of the power plant is outlined at A, and it will be observed that a pair of leads go from the commutator end of the generator to an automatic cut-out device attached to the The Modern Gasoline Automobile 661 Automatic Cut-out v fly wheel Drive Pinion Starting Motor \ Toothed F | ywhee | Fig. 341d. Practical Application of Two-Unit System Showing Relation of the Various Parts to the Power Plant. 662 The Modern Gasoline Automobile fl ,f== The Modern Gasoline Automobile 663 dash-board. From this fitting a pair of wires go to the combined switch and junction box attached to the left frame side member, as indicated. The starting motor, which is shown at B, is provided with a reduction gearing placed between the pinion on the end of the motor shaft and engaging with the teeth cut on the flywheel. The pinion on the end of the armature shaft drives a larger gear, which in turn rotates a smaller member meshing with the toothed flywheel. A storage battery is used to supply current to the start- ing motor, and also to the lights, if desired. The" location of the viirious parts and the relative proportions of the components of the starting system and power plant are so clearly outlined that further description seems unnecessary. The method of wiring the combined starting and lighting system of the two-unit type furnished on the Hupmobile is illustrated at Fio4, C. A spring of this nature replaces the usual shackle or link, and the small coil springs will yield readily to obstacles that would make no impression on the stronger leaf spring. Shock absorbers that act by producing a dampening effect to check spring movement are shown at Fig. 355. The simplest of these com- prises a pair of levers hinged together at one extremity and attached to the frame and spring, respectively. The form shown at A has a friction pad between the two portions at the hinge and this member provides the dampening effect desired. The form shown at B is somewhat different in principle. One of the levers is cup shape while the other carries a cam. A number of steel springs are inserted in the cup and excessive movement of either frame or axle is prevented 686 The Modern Gasoline Automobile by the friction effect of the three-point cam on the three compounc leaf springs inside of the cup. Many other forms of shock absorbers have been devised, some consisting of cylinders filled with oil and having a piston to act as check to prevent too rapid movement of a plunger rod working in cylinder. One member would be secured to the axle and the othe to the frame. Many makers furnish shock absorbers as an item of regular equipment, and if a car which is not equipped with these mem- bers does not ride as comfortably as desired the spring action ma) always be improved by installing some form of shock absorber be adapted to meet the conditions. Springs that are too flexible shoulc either have their action dampened or should be provided with some auxiliary buffer. Hard riding springs can be improved by the of auxiliary cushion springs as shown at Fig. 354, C. Cup filled th Grease Steel Anti-Friction Fibre Fig. 355. Efficient Shock Absorbers That Improve Spring Action on Rough Roads. A Truffault-Hartford with Friction Pad. B Connecticut Device Moves Cam Against Spring Resistance. Signals and Alarms. The laws of most commonwealths make it imperative for the motorist to equip his car with some form of warn- ing signal that will be adequate to advise other users of the highway oi the car's approach. Many forms have been devised ranging from simple reed horns operated by hand pressure on a small rubber bulb to more complex alarms in which an electric motor serves to actuate a diaphragm and produce a noise that can be heard for a long distance. The Modern Gasoline Automobile 687 A combined hand- and electrically-operated signal is shown at Fig. 356, A. An ordinary form of bulb-operated reed horn is attached to the sound intensifier of an electrically operated signal. The object Fig. 356. Forms of Motor-Car Alarms That Give Satisfactory Service. A Combined Klaxon Signal and Bulb Horn. B and C Exhaust Whistles. D Electrically Operated Signal. of combining the two alarms in one is to provide a hand-operated alarm for ordinary driving, while the louder electrical signal is em- ployed when the sound must be heard for a considerable distance. The signals shown at B and C are operated by the exhaust gases and are attached to the end of the exhaust pipe. They are operated by depressing a small foot pedal on the foot board, and various sounds may be produced from a mellow note to a shrill whistle de- pending upon engine speeds. The alarm shown at D is operated by electrical means and the diaphragm is actuated by a small electric motor which will run from the storage battery usually employed for ignition purposes. The advantage of the electrically operated sig- nals that makes them popular is apparent. The push button may be attached to the steering wheel convenient to the driver's hand and 688 The Modern Gasoline Automobile the signal may be obtained by a simple pressure of the finger, whic is sufficient to close the circuit and actuate the apparatus which pi duces the sound. Speed-Measuring Devices. When one considers the stringent lav of most communities regulating the speed of motor vehicles it wil evident that some form of speed-indicating device is necessary to si the velocity at which the car is traveling at any time. Speedometer are usually combined with odometers or mileage counters, and it is not uncommon to provide a clock as well. A speedometer has otl uses besides merely indicating the rate of travel. It forms an excel- lent indication of the value of different carburetor adjustments and it enables the motorist to compile definite figures regarding fuel oil consumption or tire depreciation for a given period of time. Various speedometer forms are shown at Fig. 357. That at A is a simple instrument to indicate the speed and distance. The tyj depicted at B indicates the total distance traversed and the number of Fig. 357. Speedometers Useful in Indicating Speed and Mileage. miles covered on each trip as well as the speed. It is provided wil a small electric lamp at the top to illuminate the dial at night. Tl speedometer shown at C has all of the features of the other tw( instruments with the added one of having a clock to indicate tl time. Speedometers are usually placed on the dashboard of the a The Modern Gasoline Automobile 689 and are driven from the front wheels by means of suitable reduction gears mounted on the steering knuckle and a flexible shaft. Speed indicators may operate on different principles, some de- pend on magnetism, or the flow of liquids, others utilize centrifugal force and operate just the same as the fly-ball governor of an engine, An instrument which depends upon the principle of centrifugal force to indicate speed is shown in section at Fig. 358. The driving Mileage Recorder vernor Weights Attachment Lug Driving Shaft Fig. 368. Sectional View of Speedometer Which Depends on Centrifugal Force Stored in Governor Weights to Actuate Indicating Needle. shaft carries a pair of weights which are thrown out as the speed increases. These weights swing a pair of segments meshing with the circular rack and impart an up and down reciprocating motion to this member as they revolve. The circular rack meshes with a small spur pinion and its reciprocating motion is converted to an oscillating one by means of the pinion. A pair of bevel gears trans- 690 The Modern Gasoline Automobile mit the motion of the spur pinion to the speed-indicating needle at the top of the apparatus. The weights and their position are so calculated that as the speed increases they fly out from center and pull down the circular rack. This, in turn, moves the spur pinion and bevel gears, and causes the needle to register the speed corre- sponding to the position of the governor weights. A small train of gearing similar in principle to that used in a bicycle cyclometer is carried between the speedometer case and the dial, and serves as a distance-recording gauge. The driving shaft to which the governor weights are attached is driven by a flexible shaft connecting to one of the front wheels in the conventional manner. It is contended that speedometers which depend on centrif- ugal force are more accurate under all conditions than those utiliz- ing either magnetism or the flow of liquids to indicate the speed. Those who favor the magnetic principle advance the contention that instruments of this character are more sensitive and will register low speeds more accurately than instruments depending upon centrif- ugal force. All of the many forms on the market have been used with success, however, and any speedometer of a reputable make is certain to furnish satisfactory service. Some form of speed-indicat- ing device should be installed on every car, and their obvious utility can be easily understood when one remembers that the amount of one fine for fast driving will pay for a very efficient speed-indicating and mileage-recording instrument. Tools and Miscellaneous Equipment. In equipping a car for the season's use many factors must be considered, as the character of the supplies and spare parts required will vary with the type and make of car, while the tools needed for repairing the mechanism will de- pend largely upon the mechanical ability of the car owner or the person in charge of the automobile. While a very complete outfit of tools and spare parts would be the best insurance against trouble, it should be remembered that the weight of the tool outfit should be kept to as low a point as possible. As a general rule comparatively few well chosen tools that would be apt to be used often would be superior to an indiscriminately selected bulky outfit by one who has no knowledge of the value of the various appliances or how to use them. In modern motor cars it is easy to find storage room for I The Modern Gasoline Automobile 691 very complete assortment of tools and supplies, and while some of these may be considered unnecessary there may be a time when it will be invaluable especially if much touring is contemplated. The first point to consider is selecting the common tools that one would be apt to need and as a guide a very complete tool roll such as sold by practically all automobile supply houses at a moderate price is shown at Fig. 359. The choice of a container for tools and supplies is very important and while the tool roll depicted, which is made I of heavy canvas or leather, is very useful it has the disadvantage of ; being inconvenient to handle. As it must be unrolled every time certain of the tools would be needed, the ground is usually the only available place for its extension and the contents and casing may become very dirty. The writer prefers to use a tool box in which a number of trays are fitted. These are divided into compartments, i each tool having a distinct space and to insure against rattle or injuring the tools the various compartments may be lined with felt or heavy cloth. A very good method of making the trays is to have these composed of or filled in with a wooden block, which is recessed , to fit the tools to be carried. A container of this nature is superior to others as the tools needed most often can be placed in the upper- most tray, making them accessible, while in a roll the tools needed most often may be carried in the center. Some motorists throw the i tools indiscriminately into a box and the result is that many of the appliances are damaged by coming in contact with other tools. The cutting edges of cold chisels and wire cutters are nicked, the teeth , of files become broken or filled up with dirt, and screw driver points , may become quickly blunted, and their utility reduced. At the same time the handles and polished surfaces of the other tools have become marred by the edges of the cutting tools. The roll illustrated has a fair assortment of useful tools of good quality. The outfit consists of two screw drivers, two pairs of pliers, two chisels and one center punch, three drift pins, a set of four files, live wrenches, soldering copper and handle, a file handle, a split pin extractor, small roll of wire solder, two small rolls of wire one soft iron and the other copper, small tin boxes containing extra -plit pins or locking cotters and lock washers, and a ball pein hammer. The wrenches include a set of three double open-end spanners, one 692 The Modern Gasoline Automobile adjustable monkey wrench, and a pipe wrench. Small and large screw drivers are provided and two pairs of pliers, one for handling Cenfer Punch Fig. 359. Tool Roll Suitable for Making All Ordinary Repairs on Automobile Mechanism. The Modern Gasoline Automobile 693 flat pieces and cutting wire, the other for turning round pieces are included. In addition to the tools shown in the outfit depicted at Fig. 359, a motorist who intends to'inake his own repairs will find those shown at Fig. 360 very useful. The valve-spring lifter is employed to com- press the valve spring when it is desired to remove the locking key or washer from the bottom of the valve stem, and will be found very useful when the valves are to be removed for cleaning or grinding. The tinner's snips can be utilized to advantage in cutting sheet metal, packings, asbestos brake lining fabrics, stock for shims and many other purposes. The hack saw and a number of extra blades will be found of value when it is desired to cut bars of brass, steel, or iron, and it can be used in cutting wood, fiber, hard rubber, and other materials as well. The adjustable end wrench should be supplied in two sizes, a six inch for small work and one eight inches long for* use on larger objects. This form of wrench is especially desirable for motor-car use as the opening between the jaws may be altered to suit requirements, and the angle of the head may be varied so it will work in some very inaccessible places where the ordinary forms of monkey wrench or open-end spanner could not be employed. A complete file set is an almost indispensable part of the equip- ment and this should include members of square, round, triangular, and rectangular sections, in order to form various surface profiles needed on motor-car parts. The flat files are usually used for smooth- ing straight surfaces, and the round and half round are employed on curved pieces. The square file and the " three-square " or " three- cornered " file, as it is often called, are very useful in filing work where sharp corners must be left. In choosing files, one has almost as much latitude as in selecting other tools because they are made in various lengths and with different degrees of cutting power. In purchasing files, it should be remembered that the finer grades are used only for finishing, while those having coarser teeth are employed for roughing out work and removing metal. The file set should include in addition to the forms shown a small fine flat file, about the size of a manicuring file, for fine work on the platinum points of spark-coil vibrators or magneto-contact breakers. Files should be carried in cloth or leather cases or wrapped in heavy paper so The Modern Gasoline Automobile 695 that the cutting surfaces will be kept clean and away from other objects. The gasoline blow torch forms part of the soldering outfit and can ho used to advantage in heating the soldering copper. It is also useful in heating nuts or bolts that have become rusted in place, and as the flame is very hot the ends of small rods may be heated sufficiently so that they may be bent into eyes or rod ends very easily. A small hand drill with a number of common sizes of drills ranging from a No. 60 to about five sixteenths, of an inch in diameter can be used so often in fitting small brackets, drilling holes in wood or metal, drilling out broken bolts or studs, and many other uses, that it will soon pay for itself. A wire brush is useful in tire work, where it can be used to roughen up the surfaces of the tube and patch before cementing or vulcanizing and for removing dirt, carbon, or solidified oil from the mechanism and for cleaning the teeth of files. A set of carbon scrapers may be included with advantage in the outfit because these are formed in such a way that much of the carbon deposit that accumulates in the combustion chamber may be removed through spark plug and valve cage openings by their use without dis- mantling the engine. A small bench vise that can be clamped to the running board of the car is of value when filing or fitting pieces that could not be held properly with a pair of pliers. A small hand vise is also useful, as this will grip pieces of wire or sheet metal stock much firmer than a pair of pliers, and as the jaws can be damped together by a winged nut no effort is required to hold the work, which is so securely held that it may be filed or hammered without dislodging it from the jaws of the vise. In addition to the tools shown a lead- or copper-headed, or reen- t'orci-d rawhide leather hammer may be included, as this can often be applied for driving bolts in and out without damaging the thread or for use against finished parts because it will not mar the surface. A set of socket or box wrenches and handle will be found useful in reaching bolt heads and nuts which are in inaccessible locations, and it is often desirable to supplement the two or three sizes of fixed ppanncrs or S wrenches usually furnished in a tool roll by a number of other sizes which will permit one to handle practically all standard 696 The Modern Gasoline Automobile nuts. A set of five may be obtained that will fit all sizes of bolts from three sixteenths of an inch to one half inch, as ten milled openings are supplied which will handle bolt heads or nuts from three eighths of an inch to fifteen sixteenths of an inch in diameter. A ratchet wrench that will fit the spark plug and one that will fit the nuts on the tire lugs have important advantages. With this form of wrench, after the box or end is placed over the nut of bolt head, it is not necessary to remove the wrench each time the handle is moved. The amount of movement permitted will vary with the con- ditions and sometimes will be only fifteen or twenty degrees. With a ratchet the handle is brought back to the starting point without moving the nut because the ratchet mechanism only holds in one direction. These wrenches are time savers wherever they can be used. A word of caution to motorists who are apt to judge tools merely by the price should be heeded. Many men who are not mechanically informed select even the simpler tools by price rather than quality. As a rule the better quality tools only cost a few cents more and will give satisfactory service during a lifetime, while cheaper ones often cannot endure the work of a single season. Cheap chisels and punches are made of soft, improperly tempered steel; cheap wrenches are made from malleable iron castings, instead of steel drop forgings; low-priced screw drivers have the blades of inferior stock and so flimsily secured in the handle that they will turn on the slightest provocation instead of loosening the screw to which they are applied. The motorist who buys cheap tools is penny wise and pound foolish and it is better to purchase fewer tools, but good ones, if economy dictates when the purchase is made. General Supplies and Spare Parts. In addition to the tools enu- merated there are many miscellaneous appliances that can be carried to advantage. Some of these are necessary only with certain types of cars, and many of the list which follows may be kept at home except when the car is taken on an extended tour which is apt to end at some distance from a convenient base of supplies. The group given at Fig. 361 has been selected because it shows many articles of equipment that have real value. Funnels to fit the water, gasoline, and oil containers should carried and it is well to use separate funnels for water, oil, ai 698 The Modern Gasoline Automobile gasoline. That used for water should have a spout the full size of the filler opening in the radiator and it is desirable that it should include a wire gauze screen to filter the water of any particles of foreign matter that might clog the circulating system. The oil funnel should be small and it can be easily carried by nesting in one of the larger funnels. Sometimes a nest of three funnels may be obtained, one fitting in the other, and the entire set of three takes no more room than one funnel would ordinarily. The gasoline funnel should have a chamois skin through which all fuel would pass when filling the tank. This will remove the water and dirt always present in gasoline and is practical insurance against carburetion troubles. A collapsible rubber water pail is useful on all types of cars, as it may be used to replenish the supply in the radiator from any way- side source when on the road or to carry water to the car for washing hands after repairs have been made. A small box of some good grease- dissolving hand soap, a clean towel and a piece of toilet soap take so little space that they can be stowed away anywhere, and their value is only apparent when a particularly dirty job of tire replacement or car repairing has been necessary on the road. A hand oil can and an oil syringe are needed to lubricate the various parts, the syringe being especially valuable to force oil at points that would not be easily reached with the hand oiler or that would require more lubri- cant than could be conveniently supplied by that method. A com- bination funnel and measure is often carried in place of an oil funnel. It is well to carry a gallon can of cylinder oil and a small can of cup grease any time that one is touring away from home when there might be doubt of obtaining the same grade generally used on the car. With the ordinary single-chamber type of gasoline tank it will be found advantageous to carry a spare container holding two gallons of fuel. This occupies but little space and is practical insurance against being stalled by lack of fuel. Calcium carbide and a pair of extra gas burners should be carried if the car is lighted by acetylene gas from a generator, and extra Tungsten bulbs if the car is electrically lighted. A small hand search light is useful in looking at the gaso- line level at night or in inspecting various points about the car where the presence of gasoline fumes would make the use of a naked flar The Modern Gasoline Automobile 699 langerous. For more extended working after nightfall, a small port- >i able trouble lamp, which will take its current from the ignition battery, will often demonstrate its worth. The character of the spare parts needed will depend entirely upon the make of car, and any component must be chosen with reference to the weaknesses of the machine under consideration. ! The selection of the smaller parts for replacement should be by an . experienced person who has had opportunity to study that make of car. It is well to have a spare valve complete with the spring re- j tention collars and locking key on any make of car. At the present I time practically all motor cars use valves that are interchangeable, and but one set for replacement is necessary. If, however, the valves arc different sizes it is well to carry one each of the exhaust and in- take. It is not necessary to carry these around on ordinary trips and they are merely provided as a safeguard when touring away from j a base of supply. It is well to carry at all times assortments of j small parts that are easily lost, such as split pins, lock washers, set i screws, taper pins, cap screws, semifinished hex nuts, some copper and ! iron washers, and a few carriage bolts of the sizes used in securing jthe fenders to the irons or the running boards to the hangers. A ; roll of soft iron wire and a roll of electric tape are very useful in ! general repair work and rubber tubing may be included with advan- j tage for repairs either to the gas piping, conveying acetylene gas to tin- lamps or the fuel line, leading from the gasoline tank to the : carburetor. Some of the. supplies needed that need not be carried on the car aiv a box of valve-grinding compound, asbestos cord and candle wicking, several sheets of emery cloth and sand paper, and a supply of spare gaskets or packing material, if these are used on any portion of the power plant. If battery-and-coil ignition is used it is well , to carry a spare set of batteries, extra primary and secondary wire, battery connectors and terminals, and either a complete coil unit or \ parts enough to make up a complete vibrator. If ignition is by a hi^li-tension magneto, a complete set of the most important brushes and contact-breaker parts may be obtained at small cost from the manufacturer. No matter what kind of an ignition system is sup- plied it is well to carry a complete set of spark plugs. These mem- 700 The Modern Gasoline Automobile bers are liable to give considerable trouble and it is much better to replace a defective member with a new one rather than attempt to repair a poor spark plug on the road. Spare oiler and fan belts are useful if either the mechanical oiler or cooling fan are driven in this manner. A complete set of tire tools and suitable equipment for tire repairing, such as considered in another chapter, should be provided. It is well to carry all smaller screws and parts in envelopes or small boxes which should be plainly marked so the contents could be ascertained at a glance without re- quiring examination. Any brightly finished steel part liable to rust should be covered with grease and wrapped in cloth or paper. All goods made of rubber should be wrapped up to protect them from oil, which has a harmful effect. Spark plugs may be carried in wooden or leather cases and they should be wrapped in such a way that they will not be jarred around, as this is liable to break the in- sulation or bend the sparking points. One of the various forms of jacks shown at Fig. 362 should be included in the equipment. This member really forms part of the tire-repair outfit, though they are used on many occasions in making repairs when the tires are not at fault. The form at A is a simple lever-operated type having a double ratchet. A series of short strokes will raise the lifting ram, while slightly altering the magni- tude of the stroke will allow the lifting ram to fall. In the jack shown at B the lifting ram is raised by means of gearing enclosed in the body of the jack. This is turned by means of a socket wrench, having a handle similar to a bit brace. In the form outlined at C the lifting .ram has a screw thread cut on it and is raised by a bevel gear worked by a hand lever, which includes the ratchet mechanism. A very substantial form of direct lift jack is shown at D. The type outlined at E is used to raise the wheels from the ground quickly and easily and is intended for garage use. These are sold in sets of four and are used by many motorists to raise the wheels from the ground and relieve the tires of the car weight when the vehicle is not liable to be used for a few days or a longer period. The selection of a suit- able jack is important, and while almost any form will be adequate to raise a light car the motorist should be sure that that used in connection with a heavy vehicle has ample capacity and that it is made Tli < Modern Gasoline Automobile 701 of steel instead of treacherous iron castings, such as incorporated in the cheaper jacks. A TIK in ir some of the miscellaneous supplies that will be found 'useful may be mentioned rawhide lacing, fan belt connectors, leather Fig. 362. Leading Types of Car-Raising Jacks. s, dry powder fire extinguisher, hose clamps, brass polish and hing cloths, covers of rubber or fabric for the lamps to protect 702 The Modern Gasoline Automobile them in wet weather and chain grips for the tires. If a cone clutch of the leather-faced type is used some clutch compound will be useful in event of harsh action or fuller's earth if the clutch slips. An emergency spring repairer, which comprises a steel forging and two clamps, enables one to make a broken spring operative and may be found of advantage if the car is operated over rough roads without shock absorbers. A coil of rope should be carried on any car that is to tour in comparatively unsettled countries, and special rope made especially for motorists' use may be obtained from the supply houses. These include thirty or forty feet of one half or three quarter inch diameter Manila rope, fitted with a heavy galvanized iron hook for attaching. The rope may be used for towing, in connection with a " Spanish Windlass " for pulling the car out of mud holes and ditches, for binding a rear wheel to get increased traction when that member drops in a mud hole, and for securing trunks and packages to the running boards or other portions of the car. It should be noted that the equipment advised is more than ordi- narily complete and it is not likely that any motorist will need more than the articles mentioned, and the majority will be able to get along very well with much less. Many of the supplies enumerated need not be carried on the car except when away from home, but it is well at all times to have a complete outfit of tools and tire repair appliances as well as necessary spare parts for eliminating tire troubles or engine derangement. How Supplies May Be Carried. A problem with many motorists is how a very complete outfit may be stowed on the average car. The views at Fig. 363 and Fig. 364 show how this difficulty has been solved on some of the leading automobiles of various types. At A the entire outfit necessary for tire restoration is carried at the back end of the car between the rear springs. The trunk case serves as an anchorage for two or three spare casings while the inner tubes and tire repair outfits, as well as many of the general supplies, are easily stowed away in the trunk. In the view of the rear end of the car shown at B a large tool box is placed back of the gasoline tank and has ample capacity to carry all tools and repair parts that would be needed for ordinary repairing. As the gasoline tank is carried back of the seat there is room under the front seat for mani 3r many The Modern Gasoline Automobile 703 supplies. The form of trunk used in carrying clothing when on a tour is outlined at C. The trunk serves merely as a container and Trunk Fig. 363. Some Conventional Methods of Storing Supplies and Equipment. protector for the standard size suit cases that are employed to hold ilif clothing or supplies. At Fig. 364, A, the very ingenious manner in which a prominent maker has utilized the space back of the seat of the torpedo roadster I'MI- slowing suit cases is shown. To gain access to these the front seals are pushed forward, the center partition between the seats is raised, and the seat back is allowed to fall. The result is that a large opening is provided through which the suit cases or other bulky sup- plies may be easily placed in the body compartments. In this the 704 The Modern Gasoline Automobile spare tires are carried at the rear end of the car while the tools that are apt to be often used are stowed away in an easily reached chest on the running board of the car. Fig. 364. How Two Leading Motor Car Manufacturers Made Provision for Carrying Spare Tires and Other Supplies. At Fig. 364, B, the special case provided for stowing away spare casings on late models of Knox cars is shown. This container is of The Modern Gasoline Automobile 705 motal and access to its interior is obtained by releasing tbe catch and sliding tbe two semicircular doors around to the back end. This view also shows the form of trunk rack provided on many touring cars to take the automobile trunk shown at Fig. 363, C. Two views which show the practical disposition of the various accessories on conventional touring cars are shown at Fig. 365. A side elevation Fig. 366. Side Elevation and Plan View of Modern Motor Car Showing Disposi- tion of Various Articles of Equipment without Hampering Passengers or Reducing Carrying Capacity. and a plan view of the vehicle is given, and the location of the es- sential accessories and supplies are so clearly shown that it would seem unnecessary to describe these in detail. The placing of the lamps, warning signal, wind shield, top, spare casings, and various cases for stowing away the smaller parts may be readily ascertained by a study of the illustrations. 706 The Modern Gasoline 'Automobile Fig. 365a. Showing Method of Utilizing the Kemco Combined Fan and Dynamo. The Modern Gasoline Automobile 707 The Kemco Combined Fan and Generator. Considerable difficulty has been experienced by motorists owning old-model cars and desiring to fit electric-lighting systems on account of no provision having been made by the makers of the car for installing or driving a suitable generator of electricity. A combined fan and dynamo which is novel in construction is shown at Fig. 365. In this the rotary member of the generator is provided with a series of fan blades and is intended to replace the cooling fan usually supplied on most cars, whether air or water cooled. The dynamo portion is very compact and very little of the efficiency of the cooling fan is sacrificed to obtain the advan- tages incidental to electric lighting. The generator is so arranged that it may be driven by the fan belt in just the same manner as the fan originally supplied with the car. A wiring diagram showing the method of installing the various components comprising the Kemco lighting system is presented at B, while the appearance and method of mounting the generator are shown in the drawing above it. CHAPTER XII Operating Advice and Explanation of Automobile-Control Methods Utility of Spark and Throttle Levers Obtaining Various Speed Ratios with Friction Transmission How Planetary Gearsets are Controlled Shift- ing Sliding Gears by Progressive and Selective Systems Standard Auto- mobile-Control Systems Described in Detail Maintenance Hints of Value Suggestions for Oiling Winter Care of Automobiles. THE basic principles of gasoline-motor-car operation are prac- tically the same in all types of cars, though the various forms of speed-changing mechanism demand distinctive methods of control in each specific case. It is not possible to give definite information that will apply to controlling all types of cars, but the general advice given can be applied to all cars, especially the instructions relating to the method of motor-speed control. The methods of regulating the motor speed will be the first point considered; then the control system when the simpler forms of transmission are used, and finally the method of obtaining various speed ratios with sliding gearsets. How the Motor Should Be Started. One of the most important points in the education of the novice motorist is the best method of starting the motor if a self-starting device is not provided. Be- fore the engine is set in motion certain precautions must be observed regardless of the make or type of car. The gasoline tank, radiator, and lubricating-oil container should be inspected to make sure there is enough fuel, water, and lubricating oil. The shut-off valve in the pipe line leading from the gasoline tank to the carburetor is opened so the fuel will flow to the vaporizer. The carburetor should be primed by means of a small plunger usually carried in the float- bowl cover, and if a small resistance is felt to the downward move- ment of the primer or if gasoline escapes from the bottom of the mixing device, this may be considered a positive indication the fuel from the tank has reached the carburetor and that gasoline is present at the spray orifice. The next step is to see that the change-speed 708 The Modern Gasoline Automobile 709 lever is in a neutral position or that the clutch pedal is disengaged. The spark-control lever, which is usually carried on the steering wheel, should be set at the full retard point. In some cars this may be at the back of the sector, while the retard position may be the other extreme in other motor cars. If one attempts to set an engine in motion by means of a hand crank with the spark lever advanced so that an early spark is ob- tained, the motor may " kick back/' and this reversal of motion, which is due to premature combustion, may sprain the wrist or break an arm. It will be well to open the throttle or gas lever a little to insure that a charge of combustible gas will be inspired into the motor. The engine should be turned over several times as briskly as possible, and then the switch which completes the electrical circuit between the battery and the ignition mechanism should be put into circuit and the switch plug inserted. The hand crank is pushed in until it engages a ratchet member on the front end of the crank shaft, and then the motor should be turned by pulling up on the starting handle with the left hand. The hand crank should always be engaged so that an upward pull will be necessary to turn the crank shaft, and a point that cannot be too firmly impressed upon the embryo motorist's mind is that gaso- line engines should always be started by pulling up on the handle of the starting crank, never by pushing down. If the starting handle has been properly placed and the engine has been turned over enough without the switch so the cylinders hold a gas charge, and the switch circuit is closed when a decided resistance is felt as the crank is turned, indicating that the piston in the cylinder in which the gas charge is about to explode is nearing the compression point, a single, quick, strong pull on the crank should be sufficient to start any properly ad- justed motor. Multiple-cylinder engines, especially those of the four- and six- cylinder type, are started much more easily than the one- and two- cylinder forms. These can often be started by turning the starting handle over briskly so the motor will take in gas but without the switch closing the electric circuit. To start the motor the switch is closed and a spark will be produced in the cylinder about to fire (only in cars equipped with battery ignition) by moving the spark lever from 710 The Modern Gasoline Automobile one end of the sector to the other. As soon as the engine becomes started it should be kept from racing by shutting down the supply of gas to the point where the motor will turn freely and yet slowly. Most hydrocarbon vehicle motors have a certain degree of flexi- bility, i. e., they may be run slow or fast, and the speed may be ac- celerated or cut down as desired within a range from 200 revolutions per minute to the maximum, which will vary with the type of motor. Spark Advance Handle i Throttle Lever Knob Accelerator Pedal Throttle Control Stem Gasoline Supply Pipe Fig. 366. Parts of Motor Control System of Peerless Car. Spark Advance Regulated by Small Hand Lever. Gas Supply Controlled by Automatic Engine Governor, Accelerator Peda! or Throttle Lever on Steering Wheel. This is an important advantage, inasmuch as it permits one to regulate the vehicle speed on most occasions by a touch of the throttle alone. The engine speed of practically all automobiles is controlled by two ways, though usually these are employed in conjunction. One of these consists of varying the time of the spark in the cylinder, the other regulating the amount of gas supplied. A typical carburetor-control system is shown in detail at Fig. 366. The Modern Gasoline Automobile 711 The throttle, in this case, may be controlled by three distinct means. One of these is a centrifugal governor which shuts off the gas supply automatically if motor speeds exceed a certain predetermined point. The governor may be temporarily dispensed with by pressing down on the accelerator pedal, which will open the throttle directly, or by means of the throttle lever carried on top of the steering column. The usual method of driving is to set the throttle lever at a point which will give the minimum speed desired and depend upon the gov- ernor to take care of other speed fluctuations. If it is necessary to get more gas than the governor will allow to pass, the accelerator pedal can be used to operate the throttle directly. The function of the spark lever is to regulate the time of sparking to the point best suited to the needs of the engine. The question of motor-speed regulations seems to be a simple one, but many motorists learn proper methods of spark- and throttle- lever placing only after considerable driving experience has been ob- tained. Motor-speed regulation depends upon two factors. First, ad- vancing the time of sparking to the most efficient point after the engine has once been started, and secondly, increasing the amount of mjxture supplied the cylinders. The spark and throttle levers, while designed to be manipulated independent of each other, usually move with a certain definite relation. It would not be good practice to run an engine with the spark lever way advanced and gas-supply throttle nearly closed ; nor would good results be obtained if the spark lever was retarded and the throttle opened as it is desired to increase the motor speed. It is not difficult to understand the function of the throttle lever and how the admission of more gas to the cylinders would act in creating more power, just as augmenting the steam supply to a steam engine will increase its capacity. The rules for manipulation of the spark lever are not so well un- derstood. In order to make clear the reason for intelligent manipula- tion of the spark handle there are certain points that must be con- sidered. On most automobiles there is a position of the spark lever, usually at the center or intermediate point of the sector over which it moves which corresponds to the normal firing point. If the spark lever is not advanced beyond this position, and the motor is turning over slowly, the gas in the c} r linders is being exploded when the 712 The Modern Gasoline Automobile pistons reach the end of their compression stroke. When the gas is fully compacted the explosion or power obtained from combustion is more powerful than if the spark fired gas which was not compressed properly. The electric spark is not produced at the exact time that the motor should be fired at all speeds, and if the spark was supplied the very instant of full compression irrespective of the speed of rota- tion, there would be no need of moving the spark lever. Not only is the current apt to lag, but it takes a certain definite amount of time to set fire to the gas. It requires the same amount of time to ignite the gas, of given composition, regardless of the speed of the motor. If the motor is only turning at a few hundred revolutions per minute there is ample time to ignite all gas charges positively, but if the motor speed increases and the explosions occur oftener, then one must compensate for the more rapidly occurring combustion periods by arranging to start igniting the gas earlier so the explosion will occur when the piston is at its highest point in the cylinder. The compensation for lag is made by advancing the spark. The spark lever on the steering wheel or column moves a commutator, if battery system is employed, or the magneto-contact-breaker box, if that form of current producer furnishes the ignition energy. The amount of spark advance needed depends on engine speed and the greater the piston velocity the more the spark should be advanced. It is possible to advance the spark lever too far, and when this occurs the gas is exploded before the piston reaches the top of its stroke and premature explosion takes place. As a result of this the upwardly moving piston is forced to overcome the resistance exerted by the expanding gas of the ignited charge in completing the remain- der of the compression stroke, and before it will return on the power stroke. The injurious back pressure on the piston reduces the capac- ity of the motor and a pounding noise similar to that produced by loose motor parts gives positive indication of premature ignition due to excessive spark advance. At the other hand, if the spark lever is not set as far forward as it should be, the explosion may be late because of the " retarded spark." If the spark occurs late in the cycle, the charge is not fired until the piston has reached its highest point and after it has completed a small portion of its downward movement. As the point of maximum com- The Modern Gasoline Automobile 713 pression is passed and the piston moves down in the cylinder, the size of the combustion chamber augments and the gas begins to ex- pand again before it ignites. Owing to the moderate compression the power resulting from explosions is less than would be the case with a higher degree of compression. To secure power it is necessary to supply more gas to the cylinders. Driving with a retarded spark pro- duces heating of the motor and is wasteful of fuel. For ordinary running the spark lever is usually placed about mid- way of its travel on the sector, and as a general rule an engine with magneto ignition does not require the frequent manipulation of the spark necessary when current is produced by chemical means. As the engine speed increases the current produced by the magneto is proportionately augmented, and the spark lever need not be advanced from the center position except under conditions which permit of exceedingly high engine speeds. The diagram presented at Fig. 367 is furnished by the Cadillac Motor Car Company to owners of its cars, and shows the position of the spark and throttle levers to obtain various engine speeds when the car is on the direct drive. At five miles per hour the throttle is practically closed and the spark lever has been advanced about a quarter of the way down the segment. To obtain a speed of eight miles per hour the spark lever is moved to the point on the steering- wheel sector indicated by the letter C. The throttle lever is not dis- turbed. Moving the spark lever about two thirds of the way on the sector will increase the speed of the car to nine miles per hour. From this point speed ratios are augmented by moving the throttle lever and the car speed increases progressively as the amount of gas supplied the engine is augmented. For higher speeds than twenty-five miles per hour the spark and throttle levers are moved toward the end of the sector and it is usual practice to advance both in conjunction beyond this point. Summing up, it will be patent that the greatest economy of fuel will result when the car is driven with as little throttle opening as possible, and with the greatest spark advance the motor speed will allow. To obtain maximum power, as in hill climbing on the direct drive, the spark lever should never be advanced beyond center and the throttle should be opened as wide as possible. For extreme high TO Miles per ho 25 Miles per hour Fig. 367. Position of Spark and Throttle Control Levers on Cadillac Car to Ob- tain Various Car Speeds with Gearing in Direct Drive. 714 The Modern Gasoline Automobile 715 speeds, the throttle should be advanced to a point about midway of its travel before the spark lever is advanced beyond that point. If this does not give the required increase in speed, the spark lever should be advanced as far as possible and the amount of gas increased, by mov- ing the throttle lever from its central position to the extreme position on the sector. Control-lever placing varies on nearly all cars, but the most common position is on top of the steering column, where they are convenient to operate and very accessible. In some cars the spark and throttle levers may be placed under the steering wheel and on one side of the steering post, one being located above the other. In other vehicles, they are disposed under the wheel and on opposite sides of the steering post. Some designers do not furnish variable spark when a magneto is provided. The magneto contact breaker is advanced to the point where the best operation under average conditions is at- tained, and motor-speed regulation is entirely by using the throttle lever or accelerator. Controlling Cars with Friction Transmission. After the engine has been started the next point is to put the automobile in motion. The means for obtaining the various speed ratios will determine the steps that should follow. When a friction or planetary transmission is in- stalled the control is very simple and usually a single lever suffices to furnish all desired speed ratios. The Carter Car control system is shown at Fig. 368 and is a good example of the simple method of control possible when friction-disk change-speed gearing is utilized. One hand lever at the side of the car serves to move the driven mem- ber to its various positions on the face of the driving member. The inner foot pedal is employed to bring the friction disks together and establish driving contact between them when the proper speed position has been selected with the hand lever. The other pedal is used to apply a running brake at the rear wheels. Motor speed is regulated by spark and throttle levers on the steering wheel. With this form of control the friction pedal is released before the engine is started and as this breaks the driving connection between the friction disks, the engine can be turned without moving the vehicle. After the motor is started in the manner previously indicated, the speed-changing lever is placed at a position about midway in its travel or so it will line up with the bulb of the horn shown in illustration. 716 The Modern Gasoline Automobile This gives one of the lowest speed ratios. To start the car the friction pedal is pressed with the left foot until sufficient pressure exists to cause the driving member to turn the driven wheels and transmit the engine power to the rear wheels. After a certain degree of headway Fig. 368. Control System of Carter Car, Which Employs Friction Transmission. has been attained, the friction pedal is allowed to return to its free position and the hand lever is pushed forward a few inches to give a slightly higher speed. The friction pedal is again depressed and The Modern Gasoline Automobile 717 when sufficient pressure is exerted the car will move forward at a higher speed. The farther forward the handle is placed, the higher the vehicle speeds, and if the handle is brought back beyond a central position a reverse motion is obtained. The friction pedal may be locked at any desired point by tilting the foot pad up by raising the heel. When it is desired to stop the car the friction pedal is released by bearing down on the lower portion of the foot pad, which loosens the ratchet lock and. by pushing on the brake pedal. It is important that the friction pedal be applied grad- ually and that it is not pressed down any farther than is necessary to drive the car. The amount of pressure will depend on the road con- ditions, and the lighter the degree of pressure the less wear will take place on the friction-wheel fiber ring. When on a hill, or in sand, the friction pedal will have to be pushed up harder than when the car is driven on a level highway with a good surface. Before the hand lever is changed from one position to another the friction pedals should always be released. An emergency braking effect may be obtained by pushing the hand lever in reverse position and applying the friction pedal if the car is going forward, or vice versa, if the car is traveling in a reverse direction. One of the advantages of the friction transmission is that it is difficult to injure it by care- less handling because there are no gears to be stripped if these are not meshed properly. The transmission is practically noiseless and speed changes are effected easily and noiselessly. Planetary Gears Easily Controlled. One of the advantages of the planetary gearset, when applied in the two-speed forward and re- verse forms is that the method of obtaining the various speed ratios is very simple and easily understood. At Fig. 369 the control system of some of the lighter Maxwell cars is shown and the various positions of the lever to obtain the different speeds are clearly indicated. On these cars, the speed of rotation of the double-cylinder motor is regu- lated by a small pedal connected to the throttle of the carburetor and a spark lever at the top of the steering column, under the steering wheel. The speed changes are obtained by a single hand lever and the hub brakes are applied by the usual form of pedal. Five positions of the handle give two neutral points, one reverse motion, and two forward speeds. 'Ordinarily the lever is in an ap- 718 The Modern Gasoline Automobile proximately vertical position and is at the neutral point between the reverse and slow speed. When pulled back from this position a re- Reverse . Throttle Change Speed Lever Foot Brake Fig. 369. Simple Speed-Regulation Method on Maxwell Cars Furnished with Planetary Gearsets. verse motion is obtained. If pushed forward the slow-speed gears are put into action. Moving the hand lever from the slow-speed position The Modern Gasoline Automobile 719 forward gives the second neutral point, while the high speed or direct drive is obtained by pushing the lever to the extreme forward position. The lever must be held in the reverse position but can be locked into low and high speeds. When running the car under conditions where it is not necessary to go into the reverse the lever may be pulled from the high-speed position to the neutral point between high and slow speeds. If the car is stopped it can be easily started forward again by pulling the handle back into slow speed from neutral position and then forward to engage the direct drive. If the handle is pulled way back out of high speed into neutral .position between slow and reverse, either of these ratios may be easily obtained. A point necessary to consider when operating a planetary transmission is that the slow and reverse speed must be applied gradually and that the engine be speeded up pretty well before either reverse or slow-speed bands are tightened. After the car has attained a certain degree of momentum on the low speed the lever should be put forward into the high-speed position gradually in order to avoid the sudden jump which always obtains when changing from the low to the high speed of a two-speed car. This jump is caused by a sudden acceleration due to the higher gearing, provided by the direct-drive position which is much higher than the maximum speed permitted by the slow-speed gears. The Ford car is one of the most popular of moderate-priced auto- mobiles and over 100,000 of the Model " T " are now on the road. The control system of this car is extremely simple and yet it is differ- ent from that of any other automobile. The gearset, which has been previously described, is a planetary type which gives two forward speeds and a reverse motion. The conventional form of steering wheel is used to control the direction of car travel, and spark and throttle levers are mounted on the steering column beneath the wheel to control the speed of the power plant. It is in the method of ob- taining the various speed ratios that the control system is distinctive. As will be seen by referring to Fig. 369, A, three pedals and a hand lever are provided on the left side of the car. The pedal on the extreme left is used to control the high- and low-speed clutches and is marked " C." That next to it, which is marked " E," is used to constrict the reverse band of the transmission and obtain reverse 720 The Modern Gasoline Automobile motion. The pedal at the right, which is provided with a letter " B " cast on its surface, is used to apply the foot brake. The hand lever engages the high-speed or direct-drive clutch when thrown forward and when pulled back it actuates the emergency Gasoline Adjustment Steering Wheel Emergency Brake and Clutch Release High and Low Speed Clutch Rev.erse Fig. 369 A. Outlining the Distinctive Control System of Ford Model " T " Automobile, Which Employs Two-Speed and Reverse Planetary Gearing. Location of Spark and Throttle Levers Clearly Shown in Inset. brake. An interlocking connection is provided so the emergency brake cannot be applied without releasing the direct-drive clutch. The lever may be set in a neutral position and the clutch will be released without applying the brake when it is approximately vertical. When the high speed is in and the hand lever is thrown way forward the high-speed clutch may be released by a light pressure on pedal " C " and a further movement of this pedal will apply the low speed. Thus one pedal gives control of both high and low speeds forward The Modern Guxolim Automobile 721 and the clutch can be released in exactly the same manner as that of a sliding-gear car when it is desired to slow up, such as for turning a corner, descending a hill or passing another vehicle. Before starting the car the hand lever must be in a vertical posi- tion, this releasing the clutch and applying the emergency brakes. To start the car, after the engine has been started in the usual man- ner, the foot is placed on the clutch pedal to keep it in a neutral position, while the hand lever is thrown as far forward as it will go. The engine is then accelerated and the clutch pedal is pushed for- ward until the slow-speed band tightens around the drum of the transmission and the car gathers headway on the lower ratio. After it has attained a certain momentum, the clutch pedal is allowed to drop back gradually into the high-speed position. The foot may then be removed until such times that the clutch must be discon- nected. Before applying the foot brake, which is done by pressing with the right foot upon the pedal marked " B," the clutch pedal should be put in neutral position with the left foot. To reverse the car, it must first be brought to a standstill. The engine is kept running and the clutch is disengaged with the hand lever, which is placed in the neutral position but not pulled far enough back to apply the emergency brake. The reverse pedal marked " R " is then pushed forward with the left foot, leaving the right one free to use on the brake pedal if needed. To stop the car, the throttle is closed so that the engine will not race ; the high speed is released by pressing the clutch pedal forward into its neutral position and ap- plying the foot brake slowly, but firmly, until the forward motion of the car is arrested. It is imperative that the foot be retained on the clutch pedal until the hand lever is pulled back to its neutral position. The placing of the spark and throttle levers is clearly shown in the inset in the right-hand corner of the cut, both levers being pulled back to accelerate the motor and pushed forward to slow it down. The same rules previously given for the manipulation of the spark and throttle levers apply just as well to this make of car. In the Liberty-Brush runabout the control system is somewhat similar to that previously described, except that the hand lever at the side of the car is operated selectively rather than progressively. The control system is shown at Fig. 370, and in the upper corner of the 722 The Modern Gasoline Automobile illustration the different positions of the lever in the gate are shown to obtain the various speeds desired. Engine speed is controlled by spark and throttle levers under the steering wheel in the usual manner. Fig. 370. Selective Change-Speed System of Liberty-Brush Light Runabout. The lever works in a gate arrangement and normally is in the position indicated by the letter N in the inset. In this neutral position the hand lever is normally straight up and down. To obtain slow speed the top of the handle is pushed out and the lever moved sideways until it is in the outer slot. The lever is then pulled back until a distinct resistance is felt, at which time the slow- speed band will be clamped around the slow-speed drum of the trans- The Modern Gasoline Automobile 723 mission and the gearing contained therein be in action. If the lever is pushed from the slew-speed position forward until another resisting X Fig. 371. Side-Control Levers and Pedals of Fierce-Arrow Sliding-Gear Cars. 724 The Modern Gasoline Automobile influence is felt, the gearing will be in reverse ratio. To engage the direct drive, the hand lever is pulled through the neutral slot and pushed forward in the inner slot. The single-foot pedal not only acts to apply the foot brake, but will automatically disengage the high- speed clutch before the brakes are applied without touching the hand lever. In driving the car on the high speed, if it is desired to slow up. to pass another vehicle or turn a corner, a slight pressure on the pedal will release the high speed. A greater degree of pressure on the pedal will apply the foot brakes. Operating Sliding Gearsets. Two sliding gear systems are fitted to motor cars, but at the present time the progressive system of con- trol has been almost entirely superseded by the selective system. The principles of operation are practically the same as relate to clutch operation and gear engagement, but in the progressive system it is necessary to move the gear-shift lever from one end of a segment to the other to obtain the range of speed. In the selective system a gate segment is utilized and the hand lever is moved only short dis- tances to select the speed required. The control system of a typical selective sliding-gear car is shown at Fig. 371. Engine-speed regulation is by spark and throttle levers at the left side of the steering wheel operated in the usual manner. Two pedals are provided and two hand levers. The pedal that is to be worked by the left foot is used to release the clutch, while that that is applied by the right foot actuates the running brake. The outer hand lever works on a notched segment and is pulled toward the operator to apply the emergency brake. The inner lever works in a gated segment and is employed to obtain the varying speed ratios. Another complete control system in which side levers are employed with all parts clearly depicted is shown at Fig. 372. These may be considered representative of conventional practice and the majority of the sliding-gear cars are controlled in practically the same manner. How Selective Gearsets are Operated. The arrangement of guid- ing gates which are used with selective systems of gearset control are shown at Fig. 373. In all of these the neutral point is usually at the center of the bars dividing the segment into slots and the lever can be easily moved in either direction to engage the speed desired. On the Peerless cars, which are provided with a four-forward speed The Modern Gasoline Automobile 725 and reverse gearset, there are three positions or slots for the speed- changing lever at the front end of the segment and two at the rear. To engage the reverse gear the lever would be placed in the slot in- dicated by the letter " R." To give the lowest forward speed the lever would be pulled out of the reverse slot and pushed forward into the adjacent one, indicated by number one; pulling the hand lever back out of this slot, into that marked number two will give the second speed. To engage the third speed the shift lever would be pulled out Fig. 372. Complete Control System of Buick Automobiles Showing Engine- Regulating Levers on Steering Wheel, Enclosed Hand Levers and Foot Control of Clutch and Running Brake. of the center slot and into the outside one and pushed forward until it filled the slot marked three. For the highest speed, the hand lever would be pulled from slot three to the outside rear slot four. On the Locomobile cars a four-speed transmission is provided, but 726 The Modern Gasoline Automobile the arrangement of the control slot differs somewhat from that used on the Peerless cars. As shown in the cut, the lever is in neutral position and can be moved sideways into either the inner or outer slot. To obtain the reverse speed the handle is pushed as far forward Peer/e* Knox Fig. 373. Change-Speed Gates for Three- and Four-Speed Selective Trans- missions. in the outer slot as it will go. Pulled back from this position but keeping it still in the outer slot will give the first speed. Pulling the lever back from point indicated by one to slot two will engage the second speed. The higher ratios are obtained in the inner slot. A forward movement of the lever engaging the third speed, while a pull back will engage the highest ratio. On Knox cars, where three forward speeds are provided, the guid- ing gate is arranged in such a manner that the reverse, first, and third speeds are obtained by pushing the lever into one of three slots at the front end of the gate, while the second-speed gears are meshed by pulling the hand lever back into the one rear slot. Tin Modern Gasoline Automobile 727 In operating a car with the selective method of control it is neces- sary that the gear-shift lever be in a neutral point if the clutch is engaged before starting the engine. After the motor has been started and is running at the proper speed, and it is desired to start the car, the first step is to release the emergency-brake lever and depress the Steering Wheel Fig. 374. Reo Control System with Single Centrally Located Gear-Shift Level and Steering Wheel on Left Side. clutch pedal so that the driving connection between the engine and gearset is interrupted. With the clutch pedal depressed fully the hand lever is pushed into the slot which will give the slowest speed ; then the clutch is allowed to engage slowly and the start forward is made on the lowest speed. After a certain degree of momentum has been attained the clutch pedal is again depressed and the speed lever 728 The Modern Gasoline Automobile shifted into the next higher speed ratio. The velocity of the car is thus gradually increased by moving the lever in steps from the lowest to the highest ratio. With any form of sliding-gear transmission it is imperative that the clutch be released every time a change of speed is to be made and the clutch should not be engaged again until the gearing is positively in mesh. When one desires to stop the car the first step is to release the clutch by pushing forward on the clutch pedal with the left foot and apply the foot brakes with the right foot. The gear-shift lever is brought into a neutral point and then the clutch may be engaged again, if desired. On many cars the emergency-brake lever and clutch- shifting mechanism are interlocked in such a manner that the clutch is released automatically when the hand-brake lever is applied. The emergency brakes of the average car are seldom used in normal opera- tion, the main reliance of most drivers being foot-operated service brakes. When it is desired to lock the car the emergency-brake lever is pulled back until the brakes are engaged and is retained in that position by a locking ratchet that engages suitable teeth cut into the brake-lever segment. There is some difference of opinion regarding the placing of the steering wheel and whether it should be on the right or left side of the car. Most American motor cars, which originally were copies of foreign productions, place the wheel and control levers at the right side of the car, because they were disposed in this manner on the European cars from which the first American vehicles were copied. The road rules in Europe are different than in this country in that a driver has to pass a vehicle going in the same direction on the right and must keep to the left of the road. This made the right hand placing of the wheel logical and desirable. In this country, however, the rules of the road are that all vehicles must keep to the right and when one passes another conveyance going in the same direction it should be passed on its left side. This makes the right-hand control, which is logical and desirable in Europe, unsuitable for road laws of this country. To be logical the steering wheel of American cars should be placed at the left side instead of the right. A number of designers follow this rule, but in order to conform as much as possible with American T. Intermediate Gear High and Intermediate Shift Member In Intermediate Speed Ratio. E- DlfcfECX DtflAE CrfUCH IM bO """"tltlllil IIU . I AYT) I Jt*( 1 Jll ^ JII L 1 I M UT to release the oJutch and apply ice brake, while the one oper- 8HA30 01 at the left side instead of the right. A number of designers Toi this rule, but in order to conform as much as possible with American The Modern Gasoline Automobile 729 practice the gear-shift lever is placed in the center of the car where it can be operated by the right hand instead of at the left side. A typical left-hand control system is shown at Fig. 374. In this a single-hand lever is mounted in the center of the floor board and is moved in four directions. It may be rocked to the right or left and pulled back or pushed forward in either of these positions. "When the Fig. 376. Speed-Change Levers of Knox Cars. lever is straight up and down it is at the neutral point, the three forward speeds and reverse motion are obtained by rocking the lever from side to side and pushing it forward or backward as conditions demand. Two pedals are provided. That at the extreme left serves to release the olutch and apply the service brake, while the one oper- 730 The Modern Gasoline Automobile ated by the right foot actuates the emergency brakes. When a single pedal is used for service-brake application and clutch release, it is Steering Wheel Engine Control Levers Emergency Brake Leue, Fig. 376. Complete Control Group of Mitchell Motor Cars. depressed about half 'its travel to disengage the clutch and applies the running brake from that point to the end of its radius of movement. The Modern Gasoline Automobile 731 Many designers who favor the right hand placing of the steering post locate the gear shift and emergency-brake levers in the center of the floor in order that the torpedo body, with which the cars are fitted, may present an unbroken and smooth appearance without any pro- jecting part or levers when viewed from either side. The placing of Running Brake Muffler Fig. 377. Center Control Levers of Jackson Cars and Pedals for Clutch-Running Brake, Accelerator and Muffler Cut-Out Operation. the change-speed and emergency-brake levers on the latest Knox cars is shown at Fig. 375. The complete control system of Mitchell cars is shown at Fig. 376. The placing of the hand levers on the Jackson car and the functions of the foot pedals are clearly depicted at Fig. 377. The instructions given for operating one type of car with selective sliding-gear transmission applies just as well to all other forms, whicli are controlled in practically the same manner and which differ only in the arrangement of the slots in the guiding gate and the location and direction of movement of the spark and throttle levers. Prac- tically the same units are used in all control systems of sliding-gear 732 The Modern Gasoline Automobile cars, i. e., two pedals and two hand levers are usually provided. One of the pedals invariably releases the clutch while the other applies the | service brake. One hand lever, always the one nearest the operator, | is used to shift the gears, while the one that works on a notched seg- ment is depended upon to apply the emergency brakes. General Driving Instructions. The following instructions apply to all types of gasoline automobiles and may be followed to advantage by all motorists. The gear-shift lever should always be placed in a neu- tral position when the car is stopped, whether it is left alone or at- tended. Gear-shift levers should always move easily and the clutch pedal of all cars equipped with sliding-gear transmission should be fully depressed before attempt is made to shift speeds. The clutch should always be applied gradually and as slowly as possible because too sudden or harsh engagement will produce stresses that will injure the tires or mechanism of the chassis. Xever allow the engine to race or run excessively fast when shifting gears, and it is well not to under- take to change speeds with either motor or car running at high speed. When changing down, i. e., from a higher to a lower gear, allow the car to slow down until its speed is about the same as that which will be produced by the lower gear ratio desired before the clutch is again engaged after the gear lever has been shifted. If difficulty is experienced in meshing the gears do not try and force them in mesh but hold the clutch pedal out for a few minutes, let the car come to almost a stop, apply the clutch quickly, and release it at once and the chances are that the troublesome shift member will have turned to a position where it will engage more easily. Some- times one or more of the gear teeth on the shift member or the gear with which it engages may be burred up on the edges and will not engage promptly, whereas other portions of the same members will have undamaged teeth that will easily slip into engagement. Always drive a car slowly and cautiously until you are thoroughly familiar with the control mechanism and the methods of stopping the car. When driving up grades on the higher ratios, if the motor shows any tendency to labor, shift back into a lower gear ratio which has been provided for that purpose. Many motorists believe that the best test of a car's ability is to rush all hills, or bad spots in roads, on the direct drive. It should be remembered that the lower speed ratios 1 .Jjei L li / , N^ =r r \ j 1 ~i f ! i ii * The Modern Gasoline Automobile 733 were provided for use at all times when employing the third or fourth spwds might produce strains in the motor. All unusual noises should jbe investigated at once, as these sounds usually presage more or less serious trouble. A gasoline car should never be driven with a slipping clutch, and it is imperative that the brakes and steering gear be fre- quently inspected to make sure that they are in proper order. One should never attempt to drive cars at high speeds unless the rtire casings are in perfect condition and the road surfaces good. In jdriving on clay or muddy roads, or on wet asphalt, care must be taken turning corners and the car should be driven cautiously to avoid langerous side slipping or skidding. When driving on unfavorable lighway surfaces always keep one side of the car on firm ground, if ^possible. Brakes should always be carefully applied, especially if the froad surfaces are wet. An automobile should never be brought to a stop in mud, clay or sand, snow or slush, if it can be avoided. When- ever road conditions are unfavorable the smooth tread tires of the Driving wheels should always be fitted with chain-tire grips to insure laving adequate traction. All motorists should familiarize themselves as much as possible ith the mechanism of their cars and should be competent to make the irdinary adjustments and minor repairs before any long trips are attempted. A full equipment of tools and spare tires and casings jshould be carried at all times. It is well to remember that the manu- facturer of the car has issued a set of instructions for its care and maintenance, and these should be followed as closely as possible be- pause intelligent care of any piece of machinery means long life and reliable service and the automobile is no exception to the rule. Suggestions for Oiling. One of the most important points to be >!<( rved in connection with gasoline-automobile operation is that all parts be oiled regularly. It is not enough to apply lubricant indis- criminately to the various chassis parts, but it must be done systemati- :ally and logically to secure the best results and insure the economical use of lubricant. The most important parts are the power plant and transmission system and the engine is but one point in the car that must be properly oiled at all times to obtain satisfactory results. Some Df the running-gear parts are relatively unimportant, others demand vj-ular inspection and oiling. 734 The Modern Gasoline Automobile A very comprehensive oiling chart is presented at Fig. 378, this showing practically all of the points that require oil as well as giving instructions regarding the character of the lubricant needed and how often it should be applied. Some of the points are governed by special instructions, these being the clutch, transmission case, timer, and rear axle. The points of the clutch which need lubricant vary with the form of clutch employed. Multiple-disk types which run in oil must be kept filled up with the proper grade of lubricant. At the other hand cone and dry-plate clutches work better without any lubri- cant between the surfaces. When a cone clutch is employed it is sometimes desirable to soften the leather facings with a little castor oil or neatsfoot oil, if the action is beginning to get hard. A transmission- gear case which is moderately tight can be rilled with a good grade of steam-engine cylinder oil, and heavy grease should not be used if the transmission shafts run on ball bearings. A heavy cylinder oil will have sufficient viscosity to cushion the teeth of the gears against shock and at the same time it will not be too heavy to flow into the bearings and lubricate them properly. Neither the transmission case nor the differential case on the rear axle should be filled with the heavy " Dope " widely sold, which may contain wood fiber or cork particles to make for more silent operation. If gearing is noisy it is either because it is worn or out of adjustment, and the use of nostrums and freak lubri- cants will not improve their operation. The rear-axle differential housing should be filled with as light mineral grease as it is pos- sible to get, those having about the consistency of vaseline being the most desirable as lubricants. Light oils should never be used in either the transmission-gear case or in the rear-axle housing, because these will not stay in place and will not have sufficient body to cushion the gear teeth. The only other point on the chart which needs explanation is lubrication of the timer interior. This should only be oiled when it is a roller contact form and then a few drops of dynamo, magneto, or spindle oil applied to the roll and the contact segments once a week is all that is necessary. If the timer is a form using platinum contact points it does not need any lubricant. Never use graphite grease or any heavy oil in a timer case because these will not only The Modern Gasoline Automobile 735 interfere with regular ignition by short circuiting the current, but they will clog up the timer and prevent the roller establishing proper con- tact with the segments. After a car is oiled it is well to go over all the exposed joints with a piece of cloth to remove the accumulations of surplus oil on the i outside of the parts which serve no useful purpose and which only act to attract and retain dust and grit. The instructions given on the chart : can be followed to advantage on all types of gasoline cars, though, of i course, the different constructions will have to be treated as the peculi- i arities of design dictate. Winter Care of Automobiles. While motoring throughout the en- I tire year is not unusual, many owners of cars, especially in those por- ' tions of the country where the winter climate is exceptionally severe, put up their car for a period. If the car is to be kept in service the most important thing to do is to provide some good antifreezing compound ; in order to prevent the water in the radiator and cylinders from con- gealing. There is some difference of opinion regarding the best solu- tion to use to prevent cracked water jackets and burst radiators. Be- fore we attempt to answer the questions often asked regarding the best antifreezing compound, it will be well to consider the requirements of ' such compounds. To begin with it should have no deleterious effects on the metals or rubber used in the circulating system. It must be ! easily dissolved or combined with water, should be reasonably cheap, , and not subject to waste by evaporation or be of such character that it will deposit foreign matter in the pipes. The boiling point should ' be higher than that of water to prevent boiling away of the solution ' at comparatively low temperature. Solutions of calcium chloride seem to be very popular with motor- ists, and the writer will first discuss the use of this substance. The freezing point of the solution depends upon the proportions of the salt to the water. An important factor to be considered is that if the parts of the circulation system are composed of different metals there is liable to be a certain electrolytic action between the salt and the dissimilar metals at the points of juncture, a certain corrosion taking place, and the intensity of this corrosive effect is only dependent upon the strength of the solution. As calcium chloride is derived from hydrochloric acid, which has very strong effect on metals, and as there 736 The Modern Gasoline Automobile may be particles of free acid in the solution, a certain undesirable corrosive action may take place. In using calcium chloride when compounding an antifreezing solu- tion care must be taken that commercially pure salt is employed as the cruder grades will liberate a larger percentage of free acid. The mis- take should not be made of using chloride of lime, which has much the same appearance, but whose corrosive action is very great. Galvan- ized iron tanks and cast aluminum water manifolds and pump casings prohibit the use of this salt as its destructive action is great on these metals. It is well to test a solution of calcium chloride for acid before plac- ing in the radiator. A piece of blue litmus paper may be obtained at any drug store and immersed in the solution. If the paper turns red it is a sign that there is acid present. Acid may be neutralized by the addition of a small quantity of slacked lime. The solutions may be made in these proportions : Two pounds of salt to the gallon of water will freeze at eighteen degrees Fahrenheit. Three pounds of salt to the gallon of water will freeze at one and five tenth degrees Fahrenheit. Four pounds of salt to the gallon will freeze at seventeen degrees Fahrenheit below zero. Five pounds of salt to the gallon will freeze at thirty-nine degrees Fahrenheit below zero. It must be remembered that the more salt to the solution, the greater the electrolytic effect and the greater the liability of the deposit of salt crystals, which may obstruct the free flow of the liquid. Glycerin is usually considered quite favorably, but it has disad- vantages. It often contains free acid, though the action on metals will be imperceptible in average solutions. While it does not attack metal piping to any extent it is sure destruction to rubber hose and should not be used in a car in which part of the circulation-system piping is of rubber. Glycerin is expensive and it is liable to decompose under the influence of heat and proportions added to the water must be higher than that of some other substances. Denatured alcohol is without doubt the best substance to use as it does not have any destructive action on the metals or rubber hose, The Modern Gasoline Automobile 737 ill not form deposits of foreign matter, and has no electrolytic effect, u solution of sixty per cent water and forty per cent alcohol will hind twenty-five degrees below zero without freezing. The chief dis- dvaiitage to its use is that it evaporates easily and its boiling point < |iiite low. Alcohol volatilizes more rapidly than water and the olution is liable to become too light as proportion of alcohol to water > roncerned. The percentages required are shown in the following: Water ninety-five per cent, alcohol five per cent, freeze at twenty- ive degrees Fahrenheit; water eighty-five per cent, alcohol fifteen >er cent, freeze at eleven degrees Fahrenheit; water eighty per cent, jlcohol twenty per cent, freeze at five degrees Fahrenheit; water .eventy per cent, alcohol thirty per cent, freeze at nine degrees Fahren- heit below zero ; water sixty-five per cent, alcohol thirty-five per cent, 'rt (/' at sixteen degrees Fahrenheit below zero. Various mixtures have been tried of alcohol, glycerin, and water, md good results obtained. The addition of glycerin to a water- plcohol solution reduces liability of evaporation to a large extent, and wrhen glycerin is used in such proportions it is not liable to damage the rubber hose. The proportions recommended are a solution of half glycerin, half alcohol to water. The glycerin in such a solution will remain practically the same, not being subject to evaporation, and water and .alcohol must be supplied if amount of solution in radiator is not enough. The freezing temperatures of such solutions of varying pro- ]( irt inns are as follows: Water eighty-five per cent, alcohol and glycer- in fifteen per cent, freeze at twenty degrees Fahrenheit; water ; seventy-five per cent, alcohol and glycerin twenty-five per cent, freeze at eight degrees Fahrenheit; water seventy per cent, alcohol and glycerin thirty per cent, freeze at five degrees Fahrenheit below ^zero; water sixty per cent, alcohol and glycerin forty per cent, freeze at twenty-three degrees Fahrenheit below zero. The proper proportions to be used must of course be governed by conditions of locality, but it is better to be safe than sorry, and make the solutions strong enough for the extreme that may be expected. Oils of various kinds are often used exclusively, as it is obvious that oil and water would not form a very good mixture. They are of the character that is often used to lubricate ice-making machinery, 738 The Modern Gasoline Automobile and are made especially to withstand low temperatures. The oil will not absorb heat as readily as water, and should only be used where exceptionally good methods of cooling are provided, such as a large radiator, all metal piping and a very positive pump. This oil will attack rubber hose and gaskets, however. It would seem to the writer, from actual experience, that wood-alcohol solutions were preferable to others as combining the greatest number of the requirements of a practical antifreezing compound. After due care has been taken with the cooling system to prevent freezing, the next point to observe is the lubrication of the motor. This will depend on the oil system used and the grades of oil which are normally employed. As a general rule it is well to use a lighter grade in the winter than that utilized during warmer weather. If the clutch is a multiple-disk member it should be filled with light oil of as high cold test as it is possible to obtain. If sight-feed glasses and exposed tubing forms part of the lubricating system or the oil tank or mechanical lubricator is carried in an exposed position it should be re- membered that this part should be inspected frequently to make sure that the oiling system is functioning properly. If an acetylene-lighting system utilizing a gas generator is fitted it is necessary that the water used in the water tank or the water jacket provided on some generators be drained off and replaced with a solution of denatured alcohol and water of the proper consistency for the degree of temperature liable to be met with. During cold weather a certain amount of difficulty is always experienced in start- ing the car, especially when one considers the low grade of gasoline used at the present time. If the motor is provided with compression relief or priming cocks, a small hand oil can should be filled with gasoline and ether mixture of proportions about half and half and kept tightly corked to prevent evaporation of the volatile liquids. On a cold morning when the motor is hard to start, this liquid may be injected into the cylinders, through the priming cock or by removing the spark plugs if relief cocks are not provided and the motor will be started without difficulty. If no priming can is available one of the methods of securing gasoline shown at Fig. 379 for priming purposes may be used to advantage. At A one of the tire valve caps is utilized as a cup to remove a certain The Modern Gasoline Automobile 739 oortion of gasoline from the tank. It is utilized by tying a piece of ?ord or wire to the end and then dropping it into the gasoline tank through the filler opening. One of these caps will hold enough gaso- line to start the ordinary four-cylinder motor. Another method of accomplishing the same result is shown at B. In this a piece of Fig. 379. Two Methods of Obtaining Gasoline from Container to Prime Cylin- ders and Facilitate Motor Starting in Cold Weather. waste is tied into a ball and dropped into the gasoline tank. When removed it is saturated with fuel and enough gasoline may be squeezed 'from the waste into the priming cocks to prime the motor. If an oil 1 squirt gun forms part of the tool equipment, this may be used to draw 'gasoline from the tank without difficulty. In extreme cold weather many motorists disconnect the fan belt m order that the air draught through the radiator will not cool the water to such a point that the engine will not run efficiently. Other motorists provide some form of a lined leather shield for the front of the radiator, as shown at Fig. 380. At A the shield is shown partly opened so that a large area of the radiator is exposed to the air. At B the opening? in the shield have been closed by the shutter-like closure mid the radiator is protected in such a way that the water will be kept warm if a stop of any consequence is made. Spot-Removing Preparations. A point that worries many motor- ists, especially those of the gentler sex, is the methods of removing 740 The Modern Gasoline Automobile oil spots which frequently are present upon the clothing of motorists. The following rules will be found valuable in this connection : Most frequent among the various kinds of spots are those due to oil or grease. Materials in delicate colors require a special treatment so their shade will not be changed. If a grease spot is to be re- moved, the main portion of the grease is first carefully scraped off by means of a knife blade. A plaster of Fuller's earth, prepared by dilut- ing the earth with a little water, is applied to the surface affected. This remains in place for several minutes, and is then scraped off. Any particles of Fuller's earth remaining on the cloth can be washed off with water. By lightly ironing out the affected portion of the garment it will be completely renovated. In no case should a solvent (benzene or gasoline) be used for re- moving spots from materials dyed in light shades, as there is danger Fig. 380. Special Cover to Protect Radiator During Cold Weather and Prevent Freezing Cooling Water. A Slots Open for Air Passage while Car is Used. B Radiator Completely Protected when Engine is Stopped. Cover Retains Heat and Makes for Easy Restarting. that the dye will be dissolved with the grease. Cotton and linen gar- ments, whether white or dyed, can be restored by local treatment with soap ; Materials that are not dyed and broadcloth may be easily cleaned by means of benzol, gasoline or alcohol-benzol mixtures, the latter being the best solvent. Material of light weight is stretched between the hands and the The Modern Gasoline Automobile 741 solvent is poured on it drop by drop until the cloth is penetrated. The degreasing process is completed by pressing the moist portion be- twrrii t\v<> pieces of clean linen. If the material is heavy such as broadcloth the spot is rubbed repeatedly with a rag of linen soaked with one of the solvents mentioned above, until the material is moistened all through, and care must be taken to discard the rag as soon as it becomes dirty, and use a clean one. Kerosene spots, which are easily formed, should first be treated with a flight coating of vegetable oil (lubricating oil; or, better, olive oil ) , so as to absorb the kerosene, and then treated with the Fuller's earth plaster, which absorbs the whole quite rapidly. Authorities recommend a number of liquid compositions tor re- moving grease spots from cloths which are not delicate. One of the simplest of these consists of Wood alcohol 2 parts Alcoholic essence of soap 2 parts Ammonia 4 parts Turpentine 4 parts The alcoholic essence of soap is prepared by dissolving some white Marseilles soap in sixteen times the amount of ninety degrees alcohol, and adding ten parts of water. The white Marseilles soap is probably substantially the same as Ivory soap. Any druggist will undertake to prepare this essence. It is sufficient to apply it moderately with a linen rag. Finally, on a road only recently tarred the motorist's clothes may be spattered with tar and their treatment is a rather delicate matter. If washable garments or fast-color materials are spotted by this ma- terial, one may, after having removed the greater portion of the tar liv si-raping, pour either benzol or gasoline drop by drop on the back side of the material, so the solvent will run through the spotted part. If the material is light colored it may be nearly completely cleaned by using a rag soaked in gasoline, and taking care to touch only the spot. This latter treatment calls for considerable skill, but with patience one is usually successful. 742 The Modern Gasoline Automobile The Vulcan Electric Gearshift. A new system of gear shifting has been recently developed which depends on the use of electric cur- rent to shift the gears instead of the usual hand lever. The steering wheel is shown at Fig. 380o, with the various speed-changing but- tons let into a box attached to the steering post. The operation of shifting a gear is very simple, consisting merely of depressing the clutch pedal and pressing down on the switch button marked with the gear ratio desired. The system is not complicated, the gears being controlled by solenoid coils, one being used for each forward speed and one for reverse. Two switches are utilized between the battery and the coils, a knife switch controlled by the clutch pedal and push button located on the steering wheel. All changes of gears are controlled by the knife switch and the push buttons on steering wheel merely arranges the circuit for the particular speed desired. A glance at the cut shows that the clutch pedal moves through a link during the first part of its motion and during the remainder picks up the link and carries it along with it. Thus the first movement is the regular operation of the clutch, but a continued operation of the clutch lever actuates the knife switch. Current flows from the battery through the solenoid coil and pulls a plunger against a magnet with a force which is given as 40 to 100 pounds. This energy is transmitted through an arm to the gear- shifting fork and gear in exactly the same manner as if the gears were operated with a hand lever. The plungers are normally in a neutral position. When the button is pressed on the control member, current passes through the coil around one of the plungers, drawing it against the magnet. It is said that the current required to make the shift is about 17 amperes, and it is claimed, further, that three hundred speed changes may be made with less current consumption than is re- quired in starting the motor with an electric starting device. An advantage claimed for this electric gearshift is that the gears cannot be stripped, for the reason that the clutch must be disengaged before a shift can be made and the gears are always in neutral before the coils can accomplish the change. Furthermore, no two speeds can be utilized at the same time, because each speed is governed independently of the others, and an interlocking device prevents the The Modern Gasoline Automobile 743 744 The Modern Gasoline Automobile operator from using any two buttons at one time, even if lie should make a mistake or be careless. The box which contains the switches and solenoid coils is mounted at the side of the gear box, and it is said that the device adds only 46 pounds to the weight of the chassis. On the S. G. V. car the control buttons are mounted in a neat aluminum box on the steer- ing wheel, one for each speed, and one for a neutral member. In operation the system is very simple. If, for instance, the fourth speed button is pushed down and the clutch is thrown out and then re-engaged, the car will remain in fourth speed. When driving in traffic on the third speed the driver may set the second speed button and by depressing the clutch pedal fully will automatically shift into second speed. In a similar manner all other changes may be made. The driver- need not lift his hand from the wheel in order to accomplish any change in the gears. Those who have witnessed the operation of this device state that the system is quiet, the only noise being a slight click as the gears engage when changed. This system is also used on the Haynes 1914 automobiles and several other types. CHAPTEE XIII Practical Hints to Assist in Locating Power-Plant Troubles Systematic Detection of Conditions to which Imperfect Operation Can Be Ascribed Faults in the Ignition System Derangements of the Carburetion Group and Their Symptoms Cooling and Lubrication Group Troubles. OXE versed in motor-car construction and repair processes does not have any difficulty in tracing the common motor troubles to their source and the expert readily recognizes the symptoms which denote faulty action of any of the power-plant components. The average motorist, who has but little mechanical experience, is apt to become hopelessly confused when even the simpler derangements, liable to oc- cur at any time, materialize. One who is not thoroughly familiar with motor-car construction will seldom locate troubles by haphazard ex- perimenting and it is only by a systematic search that the cause can be discovered and the defects eliminated. In this chapter the writer proposes to outline some of the most common power-plant troubles and to give sufficient advice to enable those who are not thoroughly informed to locate them by a logical process of elimination. The internal-combustion motor, which is the power plant of all gasoline automobiles, is composed of a number of distinct groups, which in turn include distinct components. These various appliances are so closely related to each other that defective action of any one may interrupt the operation of the entire power plant. Some of the auxiliary groups are more necessary than others and the power plant will continue to operate for a time even after the failure of some important parts of some of the auxiliary groups. The gasoline engine in itself is a complete mechanism, but it is evident that it cannot de- liver any power without some means of supplying gas to the cylinders and igniting the compressed gas charge after it has been compressed in the cylinders. From this it is patent that the ignition and car- buret ion systems are just as essential parts of the power plant as the 745 746 The Modern Gasoline Automobile piston, connecting rod, or cylinder of the motor. The failure of either the carburetor or igniting means to function properly will be immediately apparent by faulty action of the power plant. To insure that the motor will continue to operate it is necessary to keep it from overheating by some form of cooling system and to supply oil to the moving parts to reduce friction. The cooling and lubrica- tion groups are not so important as carburetion and ignition, as the engine would run for a limited period of time even should the cooling system fail or the oil supply cease. It would only be a few moments, however, before the engine would overheat if the cooling system was at fault, and the parts seize if the lubricating system should fail. Any derangement in the carburetor or ignition mechanism would man- ifest itself at once because the engine operation would be affected, but a defect in the cooling or oiling system would not be noticed so readily. The careful motorist will always inspect the motor mechanism before starting on a trip of any consequence, and if inspection is care- fully carried out and loose parts tightened it is seldom that irregular operation will be found due to actual breakage of any of the compo- nents of the mechanism. Deterioration due to natural causes matures slowly, and sufficient warning is always given when parts begin to wear so satisfactory repairs may be promptly made before serious de- rangement or failure is manifested. A Typical Engine Stoppage Analyzed. Before describing the points that may fail in the various auxiliary systems it will be well to assume a typical case of engine failure and show the process of locating the trouble in a systematic manner by indicating the various steps which are in logical order and which could reasonably be followed. In any ase of engine failure the ignition system, motor compression, and carburetor should be tested first. If the ignition system is function- ing properly one should determine the amount of compression in all cylinders and if this is satisfactory the carbureting group should be tested. If the ignition system is working properly and there is a decided resistance in the cylinders when the starting handle is turned, proving that there is good compression, one may suspect the carburetor. If the carburetor appears to be in good condition, the trouble may be caused by the ignition being out of time, which condition is possible when the timer is attached to the cam shaft by a set screw The Modern Gasoline Automobile 747 or the magneto timing gear to the armature shaft by a taper and nut retention instead of the more positive key or taper-pin fastening. It is possible that the inlet manifold may be broken or perforated, that the exhaust valve is stuck on its seat because of a broken or bent stem, broken or loose cam, or failure of the cam-shaft drive because the teeth are stripped from the engine shaft or cam-shaft gears ; or because the key or other fastening on either gear has failed, allowing that member to turn independently of the shaft to which it normally is attached. The gasoline feed pipe may be clogged or broken, the fuel supply may be depleted, or the shut-off cock in the gasoline line may have jarred closed. The gasoline filter may be filled with dirt or water which prevents passage of the fuel. The defects outlined above, except the failure of the gasoline sup- ply, are very rare, and if the container is found to contain fuel and the pipe line to be clear to the carburetor, it is safe to assume the vaporizing device is at fault. If fuel continually runs out of the mixing chamber the carburetor is said to be flooded. This condition results from failure of the shut-off needle to seat properly or from a punctured hollow metal float or a gasoline-soaked cork float. It is possible that not enough gasoline is present in the float chamber. If the passage controlled by the float-needle valve is clogged or if the float was badly out of adjustment, this contingency would be probable. When the carburetor is examined, if the gasoline level appears to be at the proper height, one may suspect that a particle of lint, or dust, or fine scale, or rust from the gasoline tank has clogged the bore of the jet in the mixing chamber. If the ignition system and carburetor appear to be in good working order, and the hand crank shows that there is no compression in one or more of the cylinders, it means some defect in the valve system. If the engine is a multiple-cylinder type and one finds poor compression in all of the cylinders it may be due to the rare defect of improper valve timing. This may be caused by a gear having altered its position on the cam shaft or crank shaft, because of a sheared key or pin having permitted the gear to turn about a half of a revolution and then having caught and held the gear in place by a broken or jagged end so that cam shaft would turn, but the valves open at the wrong time. If but one of the cylinders is at fault and the rest appear to have 748 The Modern Gasoline Automobile good compression the trouble may be due to a defective condition either inside or outside of that cylinder. The external parts may be inspected easily, so the following should be looked for : a broken valve, a warped valve head, broken valve springs, sticking or bent valve stems, dirt under valve seat, leak at valve-chamber cap or spark- plug gasket. Defective priming cock, cracked cylinder head (rarely occurs), leak through cracked spark-plug insulation, valve plunger stuck in the guide, lack of clearance between valve-stem end and top of plunger caused by loose adjusting screw which has worked up and kept the valve from seating. The faulty compression may be due to defects inside the motor. The piston head may be cracked (rarely occurs), piston rings may be broken, the slots in the piston rings may be in line, the rings may have lost their elasticity or have become gummed in the grooves of the piston, or the piston and cylinder walls may be badly scored by a loose wrist pin or by defective lubrication. If the motor is a type with a separate head it is possible the gasket or packing between the cylinder and combustion chamber may leak, either admitting water to the cylinder or allowing compression to escape. Conditions That Cause Failure of Ignition System. If the first test of the motor had showed that the compression was as it should be and that there were no serious mechanical defects and there \\a~ plenty of gasoline at the carburetor, this would have demonstrated that the ignition system was not functioning properly. If a battery is employed to supply current the first step is to take the spark plugs out of the cylinders and test the system by turning over the engine by hand. If there is no spark in any of the plugs, this may be con- sidered a positive indication that there is a broken main current lead from the battery, a defective ground connection, a loose battery ter- minal, or a broken connector. If none of these conditions are present, it is safe to say that the battery is no longer capable of delivering current. If there is no spark at the plugs, but the spark-coil vibrator functions properly, this shows that the primary wiring is as it should be and that the fault must be looked for in either the wires com- prising the secondary circuit, or at the plugs. The spark plugs may be short circuited by cracked insulation or carbon and oil deposits around the electrode. The secondary wires The Modern Gasoline Automobile 749 may be broken or have defective insulation which permits the current to ground to some metal part of the frame or motor. The battery ; strength should be tested with volt or ampere meter to determine if the voltage and amperage are sufficient. Storage-battery capacity is usually gauged by measuring the voltage while dry cells are judged by i their amperage. A storage battery should show at least two volts 1 per cell, while dry batteries that indicate less than seven amperes per ' cell are not considered reliable or satisfactory for ignition service. If there is no vibration at the coil trembler or vibrator the trouble may be due to weak current source, broken timer wires, or defective i connections at the vibrator or commutator contact points. The elec- ; trodes of the spark plug may be too far apart to permit a spark to overcome the resistance of the compressed gas, even if a spark jumps the air space, when the plug is laid on the cylinder. If a magneto is fitted and a spark is obtained between the points of the plug and that device or the wire leading to it from the magneto ' is in proper condition, the trouble is probably caused by the magneto being out of time. This may result if the driving gear is loose on the armature shaft or crank shaft, and is a rare occurrence. If no spark is produced at the plugs the secondary wire may be broken, the ground wire may make contact with some metallic portion of the chassis before it reaches the switch, the carbon collecting brushes may I be broken or not making contact, the contact points of the make-and- break device may be out of adjustment, the wiring may be attached to wrong terminals, the distributor filled with metallic particles, carbon, dust or oil accumulations, the distributor contacts may not be making proper connection because of wear and there may be a more serious derangement, such as a burned out secondary winding or a punctured condenser. If the motor runs intermittently, i. e., starts and runs only a few revolutions, aside from the conditions previously outlined, defective operation may be due to seizing between parts because of insufficient oil or deficient cooling, too much oil in the crank case which fouls I the cylinder after the crank shaft has revolved a few turns, and de- rangements in the ignition or carburetion systems that may be easily remedied. There are a number of defective conditions which may exist in the ignition group, that will result in " skipping " or irregular 750 The Modern Gasoline Automobile operation, and the following is the logical order in which the various points should be inspected ; the parts which demand inspection of tenest are considered first: weak source of current due to worn out dry cells or discharged storage batteries; weak magnets in magneto, or de- fective contacts at magneto; dirt in magneto distributor or poor con- tact at collecting brushes. Dirty or cracked insulator at spark plug will cause short circuit and can only be detected by careful exami- nation. The following points should also be checked over when the plug is inspected : Excessive space between electrodes, points too close together, loose central electrodes, or loose point on plug body, soot or oil particles between electrodes, or on the surface of the insulator. "When testing a dry battery, the terminals should be gone over carefully to make sure that all terminal nuts are tight and that there are no loose or broken cell connectors. The wiring at the coil, timer, and switch should be inspected to see that all connections are tight and that the insulation is not chafed or cracked. Defective insulation will allow leakage of current, while loose connections make for irreg- ular operation. In testing a storage battery care should be taken to remove all the verdigris or sulphate from the terminals before at- taching the testing wires. If a magneto is used there may be a short circuit in the ground wire or a poor connection at either switch lever or switch key. The timer or distributor used with a battery-ignition system may be dirty and if the device wabbles or has loose bearings, the primary contact will be very poor. The insulating ring at the timer or dis- tributor, or the fiber or hard-rubber bushings at magneto or timer may allow loss of current if they are cracked. If the ignition system employs low-tension sparking plates the igniter should be removed and examined with particular reference to the sparking or contact points which should be clean and free from pits or irregular projections. The bushing which insulates the fixed contact or anvil from the plate should be clean and free from oil or cracks. Wear in the operating mechanism of the igniter will cause irregular operation. A poor ground contact at a commutator of the high-tension system will cause irregular ignition. If a vibrator coil is employed the trembler platinum contact points should be examined for pits or carbonized particles that would in- The Modern Gasoline Automobile 751 terfere with good contact. If defective, they should be thoroughly cleaned and the surfaces of the platinum point on both vibrator spring and adjusting screw should be filed smooth to insure positive contact. The tension of the vibrator spring should not be too light or too heavy and the vibrator should work rapidly enough to make a sharp, buzzing sound when contact is established at the timer. The adjust- ing screw should be tjght in the vibrator bridge and when proper spring tension is obtained the regulating screw should be locked firmly to prevent movement. If the vibrator operates satisfactorily, but there is a brilliant spark between the vibrator points and a poor spark at the spark plug, one may assume that the coil condenser is punctured. Short circuits in the condenser or internal wiring of induction coils or magnetos, which are fortunately not common, can seldom be remedied except at the factory where these devices were made. If an engine stops suddenly and the defect is in the ignition system the trouble is usually never more serious than a broken or loose wire. This may be easily lo- cated by inspecting the wiring at the terminals. Irregular operation or misfiring is harder to locate because the trouble can only be found after the many possible defective conditions have been checked over, one by one. Common Defects in Fuel Systems. Defective carburetion often causes misfiring or irregular operation. The common derangement of the components of the fuel system that are common enough to warrant suspicion and the best methods for their location follows : First, dis- connect the feed pipe from the curburetor and see if the gasoline flows freely from the tank. If the stream coming out of the pipe is not the full size of the orifice it is an indication that the pipe is clogged with dirt or that there is an accumulation of rust, scale, or lint in the strainer screens of the filter. It is also possible that the fuel shut-off valve may be wholly or partly closed. If the gasoline flows by gravity the liquid may be air bound in the tank, while if a pressure-feed sys- tem is utilized the tank may leak so that it does not retain pressure; the check valve retaining the pressure may be defective or the pipe conveying the air or gas under pressure to the tank may be clogged. If the gasoline flows from the pipe in a steady stream the carbur- etor demands examination. There may be dirt or water in the float 752 The Modern Gasoline Automobile chamber, which will constrict the passage between the float chamber and the spray nozzle, or a particle of foreign matter may have entered the nozzle and stopped up the fine holes therein. The float may bind on its guide, the needle valve regulating the gasoline-inlet opening in bowl may stick to its seat. Any of the conditions mentioned would cut down the gasoline supply and the engine would not receive suffi- cient quantities of gas. The air-valve spring may be weak or the air valve broken. The gasoline-adjusting needle may be loose and jar out of adjustment, or the air-valve spring-adjusting nuts may be such a poor fit on the stem that adjustments will not be retained. Air may leak in through the manifold, due to a porous casting, or leaky joints in a built up form and dilute the mixture. The air-intake dust screen may be so clogged with dirt and lint that not enough air will pass through the mesh. Water or sediment in the gasoline will cause mis- firing because the fuel feed varies when the water or dirt constricts the standpipe bore. It is possible that the carburetor may be out of adjustment. If clouds of black smoke are emitted at the exhaust pipe it is positive indication that too much gasoline is being supplied the mixture and the supply should be cut down by screwing in the needle valve on types where this method of regulation is provided, and by making sure that the fuel level is at the proper height in those forms where the spray nozzle has no means of adjustment. If the mixture contains too much air there will be a pronounced popping back in the carburetor. This may be overcome by screwing in the air-valve adjustment so the spring tension is increased or by slightly opening up the gasoline- supply regulation needle. When a carburetor is properly adjusted and the mixture delivered the cylinder burns properly, the exhaust gas will be clean and free from the objectionable odor present when gasoline is burned in excess. If a muffler cut-out is provided the character of combustion may be judged by the color of the flame which issues from it when the engine is running with an open throttle after nightfall. If the flame is red, it indicates too much gasoline. If yellowish, it shows an excess of air, while a properly proportioned mixture will be evi- denced by a pronounced blue flame, such as given by a gas-stove burner. The Modern Gasoline Automobile 753 Defects in Oiling Systems. While troubles existing in the ignition or carburetion groups are usually denoted by imperfect operation of the motor, such as lost power, and misfiring, derangements of the lubrication or cooling systems are usually evident by overheating, dim- inution in engine capacity, or noisy operation. Overheating may be c-iiusi'd by poor carburetion as much as by deficient cooling or insuffi- cient oiling. When the oiling group is not functioning as it should the friction between the motor parts produces heat. If the cooling system is in proper condition, as will be evidenced by the condition of the water in the radiator, and the carburetion group appears to be in good condition, the overheating is probably caused by some defect in the oiling system. The conditions that most commonly result in poor lubrication are : Insufficient oil in the engine crank case or sump, broken or clogged oil pipes, screen at filter filled with lint or dirt, broken oil pump, or defective oil-pump drive. The supply of oil may be reduced by a defective inlet or discharge-check valve at the mechanical oiler or worn pumps. A clogged oil passage or pipe leading to an important bear- ing point will cause trouble because the oil cannot get between the working surfaces. When simple compression pressure feed lubricators are employed the check valves may be defective or the container may leak. Either of these conditions will prevent the accumulation of pressure on the surface of the oil and the feed will not be positive. The sight-feed glasses may fill with oil because the pipes leading from them to the engine are full, or because the conductor is clogged with oil wax. This gives sufficient warning, however, and the oil pipe may be easily cleared by removing it and blowing it out with air or steam under pressure. It is well to remember that much of the trouble caused by defective oiling may be prevented by using only the best grades of lu- bricant, and even if all parts of the oil system are working properly, oils of poor quality will cause friction and overheating. Defects in Cooling Systems Outlined. Cooling systems are very simple and are not liable to give trouble as a rule if the radiator is kept full of clean water and the circulation is not impeded. When overheating is due to defective cooling the most common troubles are those that impede water circulation. If the radiator is clogged or the piping or water jackets filled with rust or sediment the speed of water 754 The Modern Gasoline Automobile circulation will be slow, which will also be the case if the water pump or its driving means fail. Some cooling systems are so closely pro- portioned to the actual requirements that the stoppage of a cooling fan will be enough to cause the engine to overheat. Any scale or sediment in the water jackets or in the piping or radiator passages will reduce the heat conductivity of the metal exposed to the air, and the water will not be cooled as quickly as though the scale was not present. The rubber hose often used in making the flexible connections de- manded between the radiator and water manifolds of the engine may deteriorate inside and particles of rubber hang down that will reduce the area of the passage. The grease from the grease cups mounted on the pump-shaft bearing to lubricate that member often finds its way into the water system and rots the inner walls of the rubber hose, this resulting in strips of the partly decomposed rubber lining hang- ing down and restricting the passage. The cooling system is prone to overheat after antifreezing solutions of which calcium chloride forms a part have been used. This is due to the formation of crystals of salt in the radiator passages or water jackets, and these crystals can only be dissolved by suitable chemical means, or removed by scraping when the construction permits. Overheating is often caused by some condition in the fuel system that produces too rich mixture. Excess gasoline may be supplied if any of the following conditions are present : Bore of spray nozzle or standpipe too large, auxiliary air-valve spring too tight, gasoline level too high, loose regulating valve, fuel-soaked cork float, punctured sheet-metal float, dirt under float control shut-off valve or insufficient air supply because of a clogged air screen. If pressure feed is utilized there may be too much gas pressure in the tank, or the float controlled mechanism operating the shut-off in either the auxiliary tank on the dash or the float bowl of the carburetor may not act quickly enough. Some Causes of Noisy Operation. There are a number of power- plant derangements which give positive indication because of noisy operation. Any knocking or rattling sounds are usually produced by wear in connecting rods or main bearings of the engine, though some- times a sharp metallic knock, which is very much the same as that produced by a loose bearing, is due to carbon deposits in the cylinder The Modern Gasoline Automobile 755 heads, or premature ignition due to advanced spark-time lever. Squeaking sounds invariably indicate dry bearings, and whenever such a sound is heard it should be immediately located and oil applied to the parts thus denoting their dry condition. Whistling or blowing sounds are produced by leaks, either in the engine itself or in the gas manifolds. A sharp whistle denotes the escape of gas under pres- sure and is usually caused by a defective packing or gasket that seals a portion of the combustion chamber or that is used for a joint as the exhaust manifold. A blowing sound indicates a leaky packing in crank case. Grinding noises in the motor are usually caused by the timing gears and will obtain if these gears are dry or if they have become worn. Whenever a loud knocking sound is heard careful in- spection should be made to locate the cause of the trouble. Much harm may be done in a few minutes if the engine is run with loose connecting rod or bearings that would be prevented by taking up the wear or looseness between the parts by some means of adjustment. As a general rule the average motorist is not sufficiently informed mechanically to undertake repairs of worn motor parts, and whenever repairs of a mechanical nature are necessary it will be much more sat- isfactory and cheaper to have them done by experienced mechanics or repairmen. Ordinary adjustments may be .attempted by even the inexpert, but it should be remembered that nothing may be changed without a good reason existing for making the alteration. It is not proposed to discuss the various causes of noisy operation at length be- cause the defective conditions which are evident by noisy action can usually be remedied only by skilled labor. The common defects of the auxiliary groups have been mentioned in detail, however, because these troubles may occur on the road and it is well for the motorist to be familiar with the common derangements that may result in ir- regular engine operation or loss of power. It is not in the scope of a work of this nature to analyze fully the mechanical derangement and methods of restoration because a separate volume would be needed to bring these points out adequately enough to be of value. If the motorist follows the hints given in this chap- ter he is not likely to be stalled on the road by simpler defects which he can remedy as well as the more expert. It is well to remember that common troubles can only be located by systematic search and 756 The Modern Gasoline Automobile that causes of imperfect engine action are often located by those who do not recognize the symptoms because they follow a logical process of elimination. It must be evident that all of the defects outlined will never happen within the average experience, but the conditions defined have been named because they have occurred often enough and are sufficiently common to warrant suspicion if trouble is experienced. Brief Summary of Hints for Locating Engine Troubles. First make sure that all cylinders have compression. To ascertain this, open pet cocks of all cylinders except the one to be tested, crank over motor and see that a strong opposition to cranking is met with once in two revolutions. If motor has no pet cocks, crank and notice that oppositions are met at equal distances, two to every revo- lution of the starting crank in a four-cylinder motor. If compression is lacking, examine the parts of the cylinder or cylinders at fault in the following order, trying to start the motor whenever any one fault is found and remedied. See that the valve push rods do not touch valve stems for more than approximately -J revolution in every 2 revolutions, and that there is not more than Y 32 inch clearance be- tween them. Make sure that the exhaust valve seats. To determine this examine the spring and see that it is connected to the valve stem properly. Take out valve and see that there is no obstruction, such as carbon, on its seat. See that valve works freely in its guide. Examine inlet valve in same manner. Listen for hissing sound while cranking motor for leaks at other places. Make sure that a spark occurs in each cylinder as follows: If using battery and vibrating coil system, get commutator rotor on contact. Put switch in " on " position. See that vibrator works. Examine adjustment of vibrator. Test condition of battery. Take out spark plug, widen gap to nearly inch, lay it on the cylinder and, with switch on and vibrator working, see if spark occurs. Be sure to bring plug points closer together, almost 1/32" before replacing in cylinder. If gap in plug cannot be widened, try another plug (from a cylinder that does work). Examine all wires for proper position, good connections, breaks and short circuits. See that commutator is timed correctly. If magneto or magneto and battery with non-vibrating coil is used : Disconnect wire from spark plug, hold end about inch from cylinder. Have motor cranked briskly and see if spark occurs. The Modern Gasoline Automobile 757 Examine adjustment of interrupter points. See that wires are placed correctly and not short circuited. Take out spark plug and lay it on the cylinder, being careful that base of plug only touches the cylinder. Have motor cranked briskly and see if spark occurs. Check timing of magneto and see that all brushes are making contact. See if there is gasoline in the carburetor. See that there is gaso- line in the tank. Examine valve at tank. Prime carburetor and see that spray nozzle passage is clear. Be sure throttle is open. Prime cylinders by putting about a teaspoonful of gasoline in through pet cock or spark plug opening. Adjust carburetor if necessary. CHAPTER XIV Keeping Up the Motor-Car Chassis Common Defects of Clutches and Gear- sets Faults in Chain- and Shaft-Driving Systems Troubles in Front and Rear Axles Adjustment of Brakes Care of Miscellaneous Chassis Com- ponents Maintenance of Body Finish, Tops, and Upholstery. WHEN any defects exist in the power plant they are immediately evidenced by lost power, misfiring, overheating, or other positive indi- cations that cannot be neglected. There are many points in the chas- sis that may wear and be faulty in action that will not be immediately apparent. Deterioration may exist in the power-transmission elements which will mean a serious diminution in power, but as the motor car will run more or less capably the faults are not generally known and cannot be definitely located by motorists. There are some points where wear or loose parts may directly concern the safety of the oc- cupants of the car. For instance, any defect in either the steering gear or the brakes might result disastrously in event of failure. It is not possible to discuss all the points that may need attention or to consider at length the restoration of defective components, but it is well to consider some of the common troubles which may result in im- perfect operation and which can be easily eliminated. Common Defects in Clutches. Considering first the member of the transmission system that will affect the efficiency of the entire as- sembly when deranged, it will be well to discuss the troubles common to the various types of clutches. The defective conditions that most often materialize are too sudden engagement which causes " grabbing," failure to engage properly, slipping under load, and poor release. Clutches utilizing a leather facing will cause trouble after a time be- cause of natural wear or some defect of the friction facing. The leather may be charred by heat caused by slipping, or it may have become packed down hard and have lost most of its resiliency. The clutch spring may be weakened, or broken; this will cause the clutch to slip even if the leather facing of the cone is in good condition. 758 IHAr y CHART SHOWING CAUSING DEFECTIVE OPERA Spark Plug, Broken or Dirty Insulator Causes Irregular Ignition. Loott Fanblade Hits Radiator Causes Rattle. Leaky Petcock Causes Hilling Leak in Gasket Cau -Weak or Broken Valve Spring Causes Loss of Compression and Power. 7 " 00 Little Clearance^) Prevents Value U From Seat Valve Lift Plunger Wear er, ^ Causes Noisy Valve Mien. ^M ^ mrnitmtiytan Produce Grinding Sounds. Center Main Bearing. Worn Bushing Causes Pounaing. Lac^ofOH Produce^Sgueak. Oil Sump or Contain Must Be Kept Ml of High rire Test Cyl" )/IMON TROUBLES N OF UNIT POWER PLANT. n-fead-Wtrpeet, Scored or Pitted, iovered with Carbon, Causes Loss of " ession and Lost Power. <> merely necessary to review the action of the com- plete ignition system outlined. In the diagram shown the action is as follows: When the switch E is closed and the rotor (f ) of the spark-timing device D comes in contact with the terminal (g), the current flows from the positive terminal (m) of the battery to the switch E. From thence to the primary terminal (h) on the coil; and through the vibrator spring (e) across the points (o) which are in contact, to the adjusting screw (i) and into the bridge which supports the adjusting screw. The primary winding (b) is attached to this bridge at (j) and the cur- rent flows through it to the terminal (k), from which terminal it is carried to the point (g) on the commutator and into the rotor (f). A metal brush takes up the current at this point and it is carried to the negative terminal (n) of the battery, passing through the battery it reaches the point (m) from which it started. The current will not flow unless the circuit is complete, and it cannot be complete unless the rotor (f) touches the terminal (g). This rotor is so set on the engine and so timed in relation to the movement of the piston that it will complete the circuit only at the time the spark is desired in the cylinder. When the current flows through the primary wind- ing it makes a magnet of the core and enables it to attract the arma- ture, as a magnet will attract pieces of iron or steel, and the armature is made of magnetic material. The vibrator is composed of a piece of spring steel with a small iron button riveted to the end of it. When the circuit is complete and the core is magnetized it attracts the iron button and breaks the contact of the points at (o), thus interrupting or opening the circuit and preventing further flow of the current. The core then loses its magnetism and the vibrator spring pulls the button back and again brings the points in contact to again complete the circuit. This occurs about one hundred times per second and the rapid vibra- tion produces a pronounced buzzing sound at the vibrator. When the points (o) are in contact and the core is magnetized a very strong magnetic field flows across the wire of the secondary winding (c). When the field becomes strong enough to attract the vibrator button the circuit is broken and the current stops flowing. As soon as the current ceases to flow and the magnetic field or force 776 The Modern Gasoline Automobile becomes reduced in intensity, a strong or high voltage current is produced in the secondary winding. This current flows to the spark plug F from the secondary terminal of the coil (s) and it has suffi- cient power to jump the air gap at (p), causing a spark. The spark plug construction is such that after jumping the air gap the secondary current will flow back to the engine and from the ground terminal (1) to the terminal (t) and then back through the secondary wind- ing to the terminal (s) from which it started. The magnetic field dying down has thus produced an induced current in the secondary winding, and in addition it will also set up a self-induced current in the primary winding. As the break in the primary circuit is made at the vibrator points, a large spark would occur there and very soon burn them away. To absorb the extra current which causes this spark a condenser is connected across the points by the wires (v) and (w). When the circuit is opened at (o) the self-induced current of the primary winding flows in the same direction as the original battery current. As the condenser has less resistance than the air gap which this current would have to jump at (o) it absorbs the current, and immediately that the condenser is charged, it discharges. The contact points (o) of the vibrator being separated at this time, the current from the condenser cannot pass through them to get to its other side, but must travel back through the primary winding in the opposite direction to that in which the battery current was flowing, and thus demagnetizes the core. As the more rapid the change is made from a strong magnetic field to a weak magnetic field, the higher the voltage will be, this will considerably raise the voltage of the secondary winding and give a much better spark at the spark plug. The condenser, therefore, performs two functions, that of absorbing the undesirable spark which without it would occur at the vibrator points, and of giving a much better spark in the spark plug. Fundamentals of Magnetism Outlined. To properly understand the phenomena and forces involved in the generation of electrical energy by mechanical means it is necessary to become familiar with some of the elementary principles of magnetism and its relation to electricity. The following matter can be read with profit by those who are not familiar with the subject. Most persons know that mag- The Modern Gasoline Automobile 777 netism exists in certain substances, but many are not able to grasp the tunns used in describing the operation of various electrical de- vices because of not possessing a knowledge of the basic facts upon which the action of such apparatus is based. Magnetism is a property possessed by certain substances and is manifested by the ability to attract and repel other materials sus- ceptible to its effects. When this phenomena is manifested by a conductor or wire through which a current of electricity is flowing it is termed " electro-magnetism." Magnetism and electricity are closely related, each being capable of producing the other. Prac- tically all of the phenomena manifested by materials which possess magnetic qualities naturally can be easily reproduced by passing a current of electricity through a body which, when not under electrical influence, is not a magnetic substance. Only certain substances show magnetic properties, these being iron, nickel, cobalt and their alloys. The earliest known substance possessing magnetic properties was a stone first found in Asia Minor. It was called the lodestone or leading stone, because of its tendency, if arranged so it could be moved freely, of pointing one particular portion toward the north. The compass of the ancient Chinese mariners was a piece of this material, now known to be iron ore, suspended by a light thread or floated on a cork in some liquid so one end would point toward the north magnetic pole of the earth. The reason that this stone was magnetic was hard to define for a time, until it was learned that the earth was one huge magnet and that the iron ore, being particularly susceptible, absorbed and retained some of this magnetism. Most of us are familiar with some of the properties of the mag- net because of the extensive sale and use of small horseshoe magnets as toys. As they only cost a few pennies everyone has owned one at some time or other and has experimented with various materials to see if they would be attracted. Small pieces of iron or steel were quickly attracted to the magnet and adhered to the pole pieces when brought within the zone of magnetic influence. It was soon learned that brass, copper, tin or zinc were not affected by the magnet. A simple experiment that serves to illustrate magnetic attraction of several substances is shown at A, Fig. 383. In this, several balls are hung from a standard or support, one of these being of iron or 778 The Modern Gasoline Automobile steel, the other two of any other of the common materials or metals. If a magnet is brought close to the group of balls, only one will be .->. Causes of Blowing Back, 201. Causes of Body Finish Dulling, 767. Causes of Difficult Gear Shifting, 762. Causes of Faulty Magneto Action, 749. Causes of Friction Discs Slipping. 761. Causes of Grinding Noise in Engine, 755. Causes of Improperly Timed Ignition, 747. Causes of Irregular Ignition. 750. Causes of Knocking Sounds, 755. Causes of Xoisy Power Plant Opera- tion, 754. Causes of No Spark at Plugs, 748. Causes of Poor Compression, 748. Causes of Poor Fuel Feed from Tank, 751. Causes of Squeaking Sounds. 755. Causes of Tire Failure, 631. Caution, a Few Words of, 772. Center of Gravity, Definition of. 524. Center of Gravity, Influence on Stabil- ity, 521. Chain Protection Cases, 566. Chains, Anti-Skid Forms. 607. Chains, Non-Skid, Application of, 609. Chalmers Starting System, 653. Index 795 Change Speed Gearing, Combined with Countershaft, 502. Change Speed Gearing, Combined with Power Plant, 500. Change Speed Gearing, Combined with Rear Axle, 503. Change Speed Gearing, Face Friction, 477. Change Speed Gearing, Functions of, 475. Change Speed Gearing, Individual Clutch, 486. Change Speed Gearing, Location of, 499. Change Speed Gearing, Planetary, 481. Change Speed Gearing, Progressive Sliding Gear, 563. Change Speed Gearing, Selective Type, 492. Change Speed Gearing, Silent Chain Types, 487. Change Speed Gearing, Sliding Gear Types, 490. Change Speed Gearing, Types of, 476. Change S'peed Gearing, Utility of, 475. Chapin Carburetor Construction, 304. Charging the Gasoline Engine Cylin- der, 105. Chassis, Assembly of, 51. Chassis, Definition of, 48. Chassis Frame Construction, 51. Chassis Frame, Use of, 520. Chassis Parts, Care of, 705. Chemical Action, Producing Electric- ity by, 355. Chemistry of Combustion, 273. Circuits of Electric Lighting Systems, 681. Circuits, Magnetic, 780. ' Circulating Pumps, Centrifugal, for Water, 438. Circulating Pumps, Gear, for Water, 438. Classes of Frame Construction, 523. Classification of Motor Car Types, 69. Cleaning Mohair Tops, 768. Closing Exhaust Valve, 202. Closing Inlet Valve, 204. Clutch and Brake Interlock, 724. Clutch, Function of, 455. Clutch Materials, Frictional Adhesion of, 457. Clutches, Common Defects of, 758. Clutches, Construction of Five-Plate, 470. Clutches, Construction of Multiple- Disc, 471. Clutched, Construction of Three-Plate, 467. Clutches, Design of Cones, 462. Clutches, Factors Determining Effi- ciency of, 466. Clutches, Inverted Cone Type, 461. Clutches, M"*"l to Metal Cone Type, 463. Clutches, Methods of Retaining Fac- ing, 462. Clutches, Oak Tanned Leather Facing, 458. Clutches, Parts of Cone Forms, 459. Clutches of Planetary Gearsets, 474. Clutches, Requirements of, 456. Clutches, " Spinning " Cones, 466. Clutches, Use of Auxiliary Friction Pads, 464. Clutches, Use of Cone Brake, 466. Clutches, Value of Cork Inserts, 458. Coil for Low Tension Ignition, 390. Combination Gas and Electric Lamps, 679. Combination Kerosene and Electric Lamps, 673. Combination " Live " and " Dead " Rear Axle, r>.v.i. Combination Magneto and Battery Ig- nition System, 411. Combination of Alcohol and Acety- lene. 269. 796 Index Combination Piston and Sleeve Valves, 185. Combination Spark Plug and Relief Cock, 382. Combination Gas-Electric Drive, 508. Combined Clutch and Brake Pedal, Use of, 730. Combined Fan and Generator, 706. Combustion Chamber Design, 150. Combustion, Chemistry of, 273. Common Defects in Clutches, 758. Common Troubles of Fuel System, 751. Comparing Automobile and Locomo- tive, 47. Comparing Cannon and Gas Engine, 103. Compensating Carburetor Action, 283. Compensating for Varying Atmos- pheric Conditions, 331. Compound Spring Forms, 533. Compounds, Anti-Freezing, 735. Compressed Acetylene Gas Tank, 671. Compressed Air Starting System, 651. Compressing the Gas Charge, 105. Compression Stroke, Definition of, 106. Concentric Float Design, Advantages of, 289. Concentric Piston Ring Design, 219. Concentric Valve Construction, 167. Condenser Functions, 776. Conical Rotary Valves, 192. Cone Clutch Forms, 459. Cone Clutch, Metal to Metal Type, 463. Cone Clutch with Adjustable Springs, 464. Cone Clutches, Care of Leather Facing, 759. Cone Clutches, Causes of Harsh Ac- tion, 759. Cone Clutches, Causes of Slipping, 759. Cone Clutches, Causes of Spinning, 759. Connecting Rod, Ball Bearing. 222. Connecting Rod Bearings, 221. Connecting Rod Forms, 221. Connecting Rod, Functions of, 103. Connecting Rod, Hinged, 222. Connecting Rod, Marine Type, 222. Connecting Rods, One Piece, 222. Connecting Rods, Shapes of Sections, 224. Connections of Parts of Induction Coils, 376. Constant Level Splash Oiling System, 425. Constant Speed Dynamo, 365. Constructional Details of Pistons, 214. Construction of Breeze Carburetor, 311. Construction of Chapin Carburetor, 304. Construction of Chassis Frame, 51. Construction of Engine Base, 242. Construction of Excelsior Carburetor, 305. Construction of Ford Magneto, 367. Construction of Flywheels, 235. Construction of G and A Carburetor, 309. Construction of Gasoline Strainers, 319. Construction of Induction Coil, 375. Construction of Induction Piping, 327. Construction of Kingston Carburetor, 299. Construction of Knight Motor, 123. Construction of Magneto, 786. Construction of Magneto Generators, 393. Construction of Mercedes Carburetor, 303. Construction of Multiple - Disc Clutches, 471. Index 797 Construction of Peerless Carburetor, .SO!). Construction of Pierce Carburetor, 306. Construction of Piston Rings, 218. Construction of Schebler Model " E " Vaporizer, 298. Construction of Storage Battery, 360. Construction of Five-Plate Clutches, 470. Construction of Valve Head, 171. Construction of Valves, 170. Construction of Windshields, 684. Construction, Trend of, 40. Control System of Buick Car, 725. Control System of Carter Car, 715. Control System of Ford Car, 719. Control System of Jackson Car, 731. Control System of Knox Car, 731. Control System of Liberty -Brush Car, 721. Control System of Maxwell Car, 717. Control System of Mitchell Car, 731. Control System of Fierce-Arrow Car, 724. Control System of Reo Car, 729. Controlling Car with Friction Trans- mission, 715. Controlling Planetary Gears, 717. Conventional Frame Type, 520. Conventional Rear Axle Transmis- sion, 505. Cooling Systems, Air, 436. Cooling Systems, Defects of, 753. Cooling Systems in Use, 433. Cooling Systems, Reason for Use, 434. C'ooling Systems, Thermo-Syphon, 439. Cork Float Features, 291. Cork Inserts, Value in Clutches, 458. Cot6 Two-Cycle Motor, 248. Countershaft and Change Speed Gear- ing, 502, 503. Couple Gear JDrive System, 515. Crankcase, Barrel Type, 243. Crankcase Parts, Accessibility of, 244. Crankcase, Two-Piece, 243. Crankshaft, Built Up, 228. Crankshaft Construction, 227. Crankshaft Design, Influence of Cyl- inders on, 148. Crankshaft, Functions of. 104. Crankshaft, Two Bearing Four-Cylin- der, 231. Crankshaft, Two-Throw, 230. Crankshaft, Types Outlined, 227. Crankshafts, Ball Bearing, 233. Crankshafts, Five Bearing, 231. Crankshafts, Offset, 155. Crankshafts, Three Bearing, 231. Current Consumption of Carbon Fila- ment, 676. Current Consumption, Tungsten Fila- ment, 676. Current Flow, High Tension Coil, 775. Current Production by Chemical Ac- tion, 355. Current Strength from Storage Bat- tery, 362. Cushion Tire, Combination, 615. Cushion Tire, Dual Tread, 614. Cushion Tire, Sectional, 615. Cushion Tires, 613. Cut-out Valve, Utility of, 338. Cycle of Gasoline Engine, 106. Cyclecars, Forms of, 86. Cyclecar Engines, 260. Cylinder Casting Methods Influence Crankshaft Design, 148. Cylinder Cooling by Water. 43.1. Cylinder Cooling, Theory of, 435. Cylinder Construction Methods, 143*. Cylinder, Knox Individual, 165. Cylinder, L Head Type, 104. Cylinder, Lubricants for. 418. Cylinder, Separable Head Types, 147. Cylinder, T Head Type, 101. 798 Index Cylinder, Valve in the Head Type, 161. Cylinders Cast En-bloc, 145. Cylinders Cast Individually, Features of, 145. Cylinders Cast in Pairs, Features of, 145. Darracq, Rotary Distributor Valve, 197. " Dead " Hear Axle, 556. De Dion Eight-Cylinder Engine, 259. Defects in Sliding Gear Transmission, 762. Defects in Spark Plugs, 750. Defects in Timers or Distributors, 750. Defects in Vibrator Coils, 751. Defects in Wiring, 751. Defects of Cooling Systems, 745. Defects of Oiling Systems, 753. Defects of Planetary Transmission, 761. Defining L Head Cylinder Design, 169. Definition of Amperage, 358. Definition of Center of Gravity, 521. Definition of Chassis, 48. Definition of Compression Stroke. 106. Definition of Exhaust Stroke, 106. Definition of Friction, 415. Definition of Intake Stroke, 106. Definition of Piston Speed, 153. Definition of Power Stroke, 106. Definition of Voltage, 358. Definition of Wattage, 358. Deflector, Location of, 215. Demountable Rim Forms, 610. Denatured Alcohol as Fuel, 269. Denatured Alcohol, Use as Anti-freez- ing Compound, 737. Derangements of Friction Gearing, 761. Derivation of Lubricants, 417. Describing Conventional Exhaust Valve Operation, 125. Describing Conventional Inlet Valve Operation, 125. Description of Amplex Motor, 246. Description of Knight Sleeve Valve Operation, 127. Design of Air Cooled Engines, 444. Design of Clutch Cones, 462. Design of Combustion Chamber, 150. Design of Concentric Piston Ring, 219. Design of Eccentric Piston Ring, 210. Design of Float Bowl, 291. Design of Frames, 520. Design of French Rotary Valves, 191. Design of Leaf Springs, 527. Design of L Head Cylinder, 169. Design of Oscillating Wristpin, 218. Design of Spark Plugs, 378. Design of Valves, 169. Detachable Wheels, 638. Determining Power Needed to Propel Car, 68. Development of Float Feed Vaporizers, 285. Devices for Supplying Lubricant, 420. Diagrams, Valve Timing, 206. Diameter Limits of Flywheels, 238. Diesel System, 352. Differential Gearing, Action of. 560. Differential Gear, Purpose of, 559. Differential Gear Locks, 581. Differential Piston Design, 215. Differential Piston Two-Cycle Engine, 135. Direct Air Cooling System, 443. Direction of Air Currents, 65. Disadvantages of Chemical Current Producers, 363. Disadvantages of Gravity Oilers, 422. Disadvantages of Simple Battery. 3~>9. Disadvantages of Single Cylinder Mo- tors, 108. Index 799 Disadvantages of Spring Wheels, 596. Disadvantages of Two-Cycle Engines, 136. Disc, Rotary Valves, 190. Disposition of Exhaust Gases, 333. Distillates of Petroleum, 265. Distributor, Secondary, Action of, 370. Division of Mechanism in Groups, 46. Double Cone Rotary Valves, 191. Double Reduction Gearing in Rear Axles, 565. Drag Link, Functions of, 536. Drive System, Front Wheel, 555. Drive System Couple Gear, 518. Drive System, Hoadley, 511. Driving Chains, Adjustment of, 763. Driving Chains, Faults of, 762. Driving Chains, Proper Method of Lubricating, 763. Drive Gearing, Skew Bevel, 577. Drive, Two Wheel, 85. Drive, Four Wheel, 85, 505, 548. Driving Instructions, General, 731. Driving Magneto Armatures, 407. Drop Frame Type, 524. Dry Battery Action, 356. Dry Battery for Current Supply, 356. Drum Type Rotary Valves, 190. Dual Cylinder Castings, 145. Dual Ignition Systems, 412. Dual Tread Cushion Tire, 614. Dust Disturbance and Body Design, 62. Dynamo, Constant Speed Type, 365. Dynamo Electric Machines, 363. Dynamo Speed Governor, Action of, 365. E Early Methods of Gas Ignition, 353. Early Vaporizer Forms, 280. Eccentric Bushings in Steering Gears, 538. Eccentric Piston Ring Design, 219. Economy of Fuel, Effect of Spark Lever, 713. Edison Screw Base Lamp, 676. Edi-Swan Bulb Retention, G7(i. Efficiency of Power Transmission Systems, 452. Efficiency of Shaft Driving Method, 546. Efficiency of Side Chain Drive, 544. Efficiency of Single Chain Drive, 544. Efficiency of Worm Gearing, 564. Eight-Cylinder V Motor, 257. Electrical Alarms, 687. Electrical Ignition Means, 354. Electrically Welded Valve, 171. Electric Car Features, 37. Electric Cell, Dry Type, 356. Electric Cell, Parts *of, 355. Electric Cell, Simple Primary, 355. Electric Current, Why it Flows, 773. Electric Headlight Design, 678. Electric Ignition Systems, Elements of, 354. Electric Lamps, Combination Gas, 679. Electric Lamps, Combination Type, 673. Electric Lighting Battery, 672. Electric Lighting Fixtures, 677. Electric Lighting System, 672. Electric Lighting System, Fixtures for, 677. Electric Lighting System, Headlight for, 678. Electric Lighting System, Six Lamp, 681. Electric Lighting System, Three Lamp, 681. Electric Lighting Systems, Circuits for, 681. Electric Spark for Ignition, 354. Electric Starting Sy-tcni, 654. Electrolytic Action of Alkaline Solu- tions, 735. 800 Index Elements of Carburetor Design, 288. Elements of Electric Ignition Systems, 354. Elements of Typical Water Cooling Group, 436. Elliot Type Steering Knuckle, 543. En-Bloc Cylinder Castings, 145. Engine Base Construction, 242. Engines, Cyclecar, 259. Engine Cylinder, Functions of, 103. Engine, Darracq Rotary Valve, 197. Engine, De Dion V Type, 259. Engine Design, Influence of Cylinder Construction of, 157. Engine, Eight Cylinder Type, 257. Engine, Hewitt Piston Valve, 197. Engine, Itala Rotary Valve, 187. Engine, Maxwell " 25," 263. Engine, Mead Rotary Valve, 190. Engine, Reynolds Rotary Valve, 190. Engine Starter Forms, 648. Engine, Three-Port, Two-Cycle, 648. Engine, Two-Cycle Principles, 129. Engine, Two-Port, Two-Cycle, 130. Engines for Automobiles, Forms of, 100. Engines, Instructions for Valve Tim- ing, 209. Engines, Miesse Valveless, 185. Equipment for Motor Car, 647. Essential Elements of Gas Engine, 104. Excelsior Carburetor Construction, 305. Excessive Spark Advance, Effect of, 712. Exhaust Gases, Disposition of, 333. Exhaust Manifold with Ejector Ac- tion, 337. Exhaust Operated Alarms, 687. Exhaust Stroke, Definition of, 106. Exhaust Valve Closing, 202. Exhaust Valve Lead Given, 202. Exhaust Valve Operation, Description of, 125. Exhausting the Burnt Gas, 106. Exploding the Gas Charge, 105. Face Friction Gearing, 477. Factors Determining Efficiency of Cone Clutches, 466. Factors Determining Flywheel Diam- eter, 238. Factors Determining Flywheel Weight, 235. Fan Blade Spoke Flywheels, 236. Fans for Circulating Air, 446. Fans for Cooling Systems, 442. Faults of Chain Driving Systems, 762. Faulty Magneto Action, Causes of, 749. Features of Cork Floats, 291. Features of Cylinders Cast in Pairs, 145. Features of Electric Cars, 37. Features of Four-Cylinder Motor, 118. Features of Individually Cast Cylin- ders, 145. Features of Holley Carburetor, 301. Features of Hollow Metal Floats, 291. Features of Knight Motor, 121. Features of Knox Cylinder Head, 165. Features of Low Tension Ignition Sys- tem, 389. Features of Multiple-Disc Clutches, 471. Features of Two-Cylinder Motor, 117. Features of Unit Power Plants, 137. Features of Valve Location, 160. F. I. A. T. Double Jet Carburetor, 314. Fiber Friction Ring, Life of, 761. Figuring Frontal Area of Auto, 63. Fire Inflation Gauges, 631. Five Bearing Four-Cylinder Crank- shafts, 231. Five Plate Clutch Construction, 470. Index 801 Fischer Slide Valve Motor, 212. Fixtures for Electric Lighting, 677. Fixed Winding Type Magneto, 402. Flat Seat Valve, 170. Flexibility of Automobile Power Plants, 710. Float Bowl Design, 291. Float Feed Carburetor Action, 287. Float Feed Vaporizers, Development of, 285. Floating Type Rear Axle, 557. Floats, Cork, 291. Floats, Hollow Metal, 291. Flow of Magnetic Energy, 780. Flywheel, Blower Type, 448. Flywheel Construction, 235. Flywheel, Function of, 235. Flywheel, Function of, 104, 235. Flywheel Retention by Flange and Bolts, 239. Flywheel Retention by Gib Key, 239. Flywheel Retention by Taper and Key, 239. Flywheel Weight, Factors Determin- ing, 235. Flywheels, Factors Determining Diam- eter, 238. Flywheels, Interpretation of Marks, 208. Flywheels, Method of Marking Rims, 241. Flywheels, Retention of, 238. Flywheels with Fan Blade Spokes, 236. Forced Circulation System, 435. Ford Magneto, Action of, 367. Ford Model " T," Control System of, 719. Forms of Auxiliary Air Valves, 294. Forms of Camshafts, 225. Forms of Cone Clutches, 459. Forms of Connecting Rods, 221. Forms of Electrical Ignition, 354. Forms of Engines Commonly Used, 100. Forms of Flywheels, 235. Forms of Front Axles, 541. Forms of Gasoline Spray Nozzles, 293. Forms of Induction Manifolds, 327. Forms of Jacks, 700. Forms of Magnets, 779. Forms of Mixing Chambers, 289. Forms of Mufflers, 335. Forms of Oil Pumps, 423. Four-Cycle Engine Action, 102. Four-Cycle Power Plant, 253. Four-Cylinder Engine Ignition Sys- tem, 387. Four-Cylinder Induction Manifolds, 323. Four-Cylinder Motor, Sequence of Cycles, 112. Four-Cylinder Vertical Motor Fea- tures, 118. Four Speed Selective, Gearset Design, 497. Four-Wheel Drive, 84. Four- Wheel Drive Chassis, 507, 546. Frame Construction, Classes of 523. Frame Construction, Materials Used, 522. Frame Construction, Pressed Steel, 523. Frame Construction, Steel Tubing, 522. Frame Construction, Wood, 522. Frame Design, 520. Frame Suspension Means, 525. Frame Types, Conventional, 520. Frame Types, Under slung, 521. Frame, Utility of, 520. Frames, Drop Type, 524. Frames, Methods of Spring Attach- ment, 531. Frames, Upswept Type, 524. Freezing Point of Alcohol Solutions, 737. Freezing Points of Calcium Chloride Solutions, 736. 802 Index French Rotary Valve Design, 191. Frictional Adhesion of Clutch Mate- rials, 457. Friction Clutch Operation, 457. Friction, Definition of, 415. Friction Gearing, Defects of, 761. Friction Pedal, Operation of, 717. Friction Transmission for Shaft Drive, 479. Friction Transmission, Operation of, 477. Friction Transmission, Side Chain Drive, 479. Friction Transmission, Single Chain Drive, 479. Frontal Area of Automobiles, Figuring of, 63. Front Axle Forms, 541. Front Axle, I Beam, 541. Front Axle, Tubular, 541. Front Axle, Care of, 764. Front End Suspension, 528. Front Hub Bearings, 543. Front Hub Construction, 542. Front Wheel Bearings, Adjustment of, 764. Front Wheel Brakes, 574. Front Wheel Brakes, Disadvantages of, 577. Front Wheel Brakes, Operation of, 577. Front Wheel Drive, 552. Fuel Consumption of Knight Motor, 129. Fuel System, Common Troubles of, 751. Fuels for Engines, Alcohol, 267. Fuels for Engines, Benzol, 266. Fuels for Engines, Camphor, 345. Fuels for Engines, Gasoline, 265. Fuels for Engines, Kerosene, 267. Fuels for Engines, Solid Gasoline, 271. Full Elliptic Springs, 527. y Function of Clutch, 455. Function of Flywheel, 104, 235. Function of Spark Plug, 104. Function of Wristpin, 216. Functions of Change Speed Gearing, 475. Functions of Connecting Rod, 103. Functions of Crankshaft, 103. Functions of Drag Line, 536. Functions of Engine Cylinder, 103. Functions of Motor Car Parts, 47, 49. Functions of Piston, 103. Functions of Piston Rings, 218. Functions of Shock Absorbers, 684. Functions of Spark Gap, 343. Functions of Spring Shackles, 528. Functions of Timer and Distributor, 367. Functions of Tie Bar, 535. Functions of Two-Cycle Cylinder Ports, 132. Functions of Vibrator, 775. Fundamentals of Magnetism, 776. G and A Carburetor Construction, 309. Gas Charge in Cylinder, Compression of, 105. Gas Charge in Cylinder, Exhausting, 106. Gas Charge in Cylinder, Explosion of, 105. Gas Charge in Cylinder, Pressure of, 105. Gas Engine and Cannon Compared, 103. Gas Engine, Essential Elements of, 104. Gas Mixture Supply Regulation. 295- Gas Supply Regulation by Governor, 296. Gasoline Car, Advantages of, 37. Gas-Electric Drive, 508. Index 803 Gasoline Engine, Cycle of, 106. Gasoline Engine Cylinder, Charging the, 105. Gasoline Engine Ignition System, 353. Gasoline Engine Starters, 648. Gasoline Strainers, Construction of, 319. Gasoline Strainers, Installation of, 319. Gasoline Strainers, Utility of, 319. Gasoline Supply by Gravity Feed. 277. Gasoline Supply by Pressure Feed, 277. Gasoline Supply by Pump, 279. Gauges for Tire Inflation, 631. Gearing, Bevel and Spur Combination, 568. Gearing, Double Reduction Axle, 565. Gearing, Face Friction, 477. Gearing for Camshaft Drive, 179. Gear Pump, Oil, 423. Gear Shifting, Cause of Defects in, 672. Gear Shifting on Knox Cars, 726. Gear Shifting on Locomobile Cars, 726. Gear Shifting on Peerless Cars, 725. Gearshift, Vulcan Electric, 742. General Driving Instructions, 732. General Supplies for Repairing, 696. Generator for Acetylene Gas, 669. Glycerine, Use of, as Anti-Freezing Compound, 736. Gravity Feed Systems, 277. Gravity Oilers, Disadvantages of, 422. Grinding Noises in Engine, Causes of, 755. Hand Wheel Movement in Steering Gears, 539. Heat Loss Through Exhaust Valve, 4:54. Heat Loss Through Water Jacket, 434. Helical Coil Spring Suspension. 533. Hewitt Piston Valve Motor, 197. Hickory, Use of, in Wheels, 591. High Tension Coil, Action of, 774. High Tension Ignition System, 387. High Tension Magnets, Action of, 789. Hinged Connecting Rod, 222. Hints for Tire Manipulation, 624. Hoadley System Tractor, 509. Holley Carburetor Features, 301. Holley Hot and Cold Air Shutter, 331. Holley Kerosene Carburetor, 321. Hollow Metal Float Features, 291. Horizontal Single-Cylinder Motor, 107. Horizontally Split Two Piece Crank- case, 243. How Automobiles are Steered, 533. How Current is Induced, 776. How Gasoline Engine Works, 102. How Supplies are Carried, 702. How to Keep Hands Soft, 771. How to Magnetize Iron and Steel, 780. How to Prevent "Kick Back," 709. Hubs, Construction for Front Wheels, 542. Hupp Cam Case Assembly, 178. Hydraulic Valve Operation Means, 175. I Beam Front Axle, 541. Igniter Plate for Low Tension Igni- tion, 390. Igniter Plate, Operation of, 391. Ignition by Electric Spark, 354. Ignition by Flame, 353. Ignition by Hot Head, 354 Ignition by Incandescent Tube, 353. Ignition Magneto, Parts and Func- tions, 396. 804 Index Ignition Magneto, Spacing of Contacts, 395. Ignition Magnetos, Forms of, 405. Ignition Magnetos, Installation of, 406. Ignition Magnetos, Methods of Reten- tion, 407. Ignition Magnetos, Speed of Armature, 395. Ignition Magnetos, Systems Used, 39G. Ignition Out of Time, Causes of, 747. Ignition Starters, 650. Ignition System, Causes of Failure, 753. Ignition Systems, Battery, 387. Ignition Systems, Distributor, 388. Ignition Systems, Early Types, 353. Ignition Systems, Gasoline Engine, 353. Ignition Systems, Magneto, 396. Ignition Systems; Six-Cylinder, 389. Ignition, Time of, 205. Impediments to Water Circulation, 754. Incandescent Bulbs for Electric Lamps, 675. Indirect Valve Operation Method, 174. Individually Cast Cylinder, Features, 145. Individual Clutch Change Speed Gear- ing, 486. Individual Clutch Gearset with Silent Chains, 487. Individual Pump Oiling Method, 431. Induction Coil Action, Theory of, 375. Induction Coil, Connections of Parts, 376. Induction Coil Construction, 375. Induction Coil, Typical Form, 375. Induction Manifold for Kerosene, 323. Induction Manifold Forms, 327. Induction Manifolds, Four-Cylinder, 329. Induction Manifold, Six-Cylinder, 330. Induction Piping, Built up, 327. Induction Piping, Cast Forms, 327. Induction Piping, Construction of, 327. Influence of Cylinder Construction on Engine Design, 157. Inlet Valve Closing, 204. Inlet Valve Opening, 203. Inlet Valve Operation, Description of, 125. Installation of Gasoline Strainers, 319. Installation of Magnetos, 406. Installation of Power Plants, 137. Installation of Spark Plugs, 381. Instruction for Valve Timing, 200. Insulation for Induction Coils, 376. Insulation for Secondaiy Distributor, 370. Insulation for Timer Contacts, 370. Insulation Materials for Plugs, 380. Insulation, Mica for Spark Plugs, 379. Insulation, Porcelain for Spark Plugs, 379. Intake Stroke, Definition of, 106. Internal Brake, Cam Expanded, 570. Internal Brake, Toggle Expanded, 570. Interpretation of Flywheel Marks, 208. Inverted Cone Clutch Construction, 461. Iron and Steel, How to Magnetize, 780. Irregular Ignition, Causes of, 750. Irreversible Steering Gears, 535. Itala Rotary Valve Motor, 187. Jack, Forms of, 700. Jacks, Car Lifting, 700. Jackson Cars, Control System of, 731. Janney-Steinmetz Air Starter, 652. Joining Cells in Multiple, 358. Joining Cells in Multiple Series, 358. Index 805 Joining Cells in Series, 358. Joints in Piston Rings, 219. Judging Combustion by Color of Ex- haust, 752. K Kerosene as Engine Fuel, 267. Kerosene Carburetor, Holley 1914, 341. Kerosene Supply by Injection, 324. Kerosene Vaporizer Using Water Spniy, 339. " Kick Back," How to Prevent, 709. Kingston Carburetor Construction, 299. Knight Motor, Fuel Consumption of, 129. Knight Motor Test Results, 128. Kni-ht Sleeve Valves, 123, 184. Knight Sleeve Valves, Operation of, 127. Knight Slide Valve Motor Features, 121. Knight Sliding Sleeve Valves, 185. Knocking Sounds, Causes of, 755. Knox Cars, Control System of, 731. Knox Cars. Gear Shifting Methods, 726. L Head Cylinder Construction, 164. L Head Cylinder Design, 169. Laminated Leaf Springs, 526. Laminated Wood Frames, 522. Lamps for Acetylene Lighting. 671. Lamps for Electric Lighting, 673. Lanchester Wick Carburetor, 290. Lead Given Exhaust Valve. 202. Leaf Springs, Design of, 527. Leather Auto Tops, Method of Treat- ini.'. 769. Leather Clutch Facings, Care of, 759. Leather, Oak Tanned for Clutches, 458. Leather, Retaining Facings of Cone, 462. Leather, Retention by Rivets, 462. Leather, Retention by T Bolts, 462. Leather Top Treatment, Preparations for, 769. Left Hand Control, Advantages of, 728. Legros Two-Cycle Motor, 248. Liberty-Brush Runabout, Control Sys- tem of, 721. Life of Fiber Friction Rings, 761. Light Cars, Foreign, 87. Lighting System, Acetylene Gas, 669. Lighting System, Electric, 672. Lighting Systems, Motor Car, 668. Liquid Fuel Application, 264. Liquid Fuel Storage, 277. " Live " Rear Axle, 556. Locating Power Plant Troubles, 745. Location of Change Speed Gearing, 499. Location of Deflector, 215. Location of Motor Car Parts, 47, 49. Locks, Differential Gear, 581. Locomobile Cars, Gear Shifting Method, 726. Long Stroke Advantages, 150. Loosening Clincher Shoes, 625. Low Tension Igniter Plate, 390. Low Tension Ignition, Coil for, 391. Low Tension Ignition, Disadvantages of, 392. Low Tension Ignition System, 389. Low Tension Ignition Wiring Scheme, 391. Low Tension Magnets, Action of, 788. Lubricants, Cylinder, 418. Lubricants, Derivation of, 417. Lubricants-, Devices for Supplying, 420. 806 Index Lubricants, Fire Test of Cylinder Oil, 419. Lubricants, Flash Test of Cylinder Oil, 419. Lubricants, Fluid, 417. Lubricants, Oleo-Xapthas, 417. Lubricants, Organic, 417. Lubricants, Qualities Needed, 416. Lubricants, Semi-Solid, 417. Lubricants, Solid, 417. Lubricating System, Winter Care of, 738. Lubrication, by Centrifugal Force, 433. Lubrication, Gravity Method, 425. Lubrication, Individual Pump Sys- tem, 431. Lubrication, Mechanical, 423. Lubrication of Driving Chains, 763. Lubrication of Mechanism, Reason for, 414. Lubrication, Positive Systems, 423. Lubrication, Pressure Feed, 430. Lubrication, Splash System, 425. Lubrication, Theory of, 416. Lubricators, Individual Pump Type, 431. Lubricators, Mechanical, 423. Lubricators, Sight Feed Gravity Cups, 420. Lubricators, Types of, 420. M Magnet Forms, 779. Magnetic Circuits, 780. Magnetic Substances, 777. Magnetism, Flow of, 780. Magnetism, Fundamentals of, 776. Magnetism, How to Impart to Iron or Steel, 780. Magnetism, Lines of Force Defined, 779. Magnetism, Relation to Electricity, 777. Magneto Action, Basic Principles, 787. Magneto, Action of Transformer Sys- tem, 788. Magneto, Action of True High Ten- sion, 789. Magneto Armatures, Methods of Driv- ing, 407. Magneto-Generator Construction, 393. Magneto Ignition, Double System, 410. Magneto Ignition, Dual System, 412. Magneto Ignition Systems, 396. Magneto, Parts and Functions, 785. Magnetos, Wiring of High Tension, 398. Magnetos, Wiring of Transformer Type, 400. Magneto with Fixed Winding, 402. Maintenance of Body and Upholstery, 766. Manifolds for Oil Distribution, 428. Marine Type Connecting Rod, 222. Materials for Frame Construction, 522. Materials, Metallic, for Clutches, 457. Materials Used in Tire Construction, 598. Maxwell " AA," Control System of, 717. Mead Rotary Valves, 190. Mechanically Fastened Tire Tools, 626. Mechanical Oiling Methods, 423. Mechanical Production of Electricity, 363. Mechanical Starters, 649. Mechanism, Division in Groups, 46. Mercedes Carburetor Construction. 303. Mercedes Steering Knuckle, 543. Metal Automobile Wheel Types, 591. Metal, Cast Automobile W 7 heels, 591. Metallic Materials Used in Clutches, 457. Method of Cone Clutch Operation, 460. Method of Indirect Valve Operation, 174. Index 807 Method of Leather Retention, Cone Clutches, 462. Method 01 Marking Flywheel Rim, 241. Method of Using Starting Crank, 709. Methods of Air Cooling, 436. Methods of Constructing Crankshafts, 227. Methods of Cylinder Construction, 143. Methods of Driving Cam Shaft, 179. Methods of Flywheel Retention, 238. .Methods of Oil Distribution, 424. Methods of Valve Operation, 174. Methods of Valve Placing, 161. Methods of Wiring Primary Cells, 357. Methods of Wristpin Retention, 216. Mica Insulated Plug, 378. Miscellaneous Chassis Parts, Care of, 765. Miscellaneous Supplies, 701. Mitchell Car, Control System of, 731. Mixing Chamber Forms, 289. Mohair Auto Tops, Method of Clean- ing, 768. Motor Car Alarms, 687. Motor Car Alarms, Electrical, 687. Motor Car Alarms, Exhaust Oper- ated, 687. Motor Car Brakes, Adjustment of, 765. Motor Car Equipment, 647. Motor Car Lighting Systems, 668. Motor Car Maintenance, Supplies for, 698. Motor Car Parts, Functions of. 47, 49. Motor Car Parts, Location of, 47, 49. Motor Car Principles, 43. Motor Car Repairs, Tools, for, 693. Motor Car Types, Classification of, 69. Motor Control Levers, Mounting on Steering Gear, 541. Motor Control Systems, Typical, 710. Motor Installation, Under Seat, 141. Motor, Knight Slide Valve, 121. Motor Speed Regulation, 711. Muffler Forms, 335. Mufflers, Water-cooled, 336. Multiple Connection for Cells, 358. Multiple-Disc Brake, 573. Multiple-Disc Clutches, Care of, 759. Multiple-Disc Clutches, Features of, 471. Multiple-Nozzle Carburetors, 311. Multiple-Series Connections for Cells, 358. Mushroom Cam Follower, 174. X Natural Circulation System, 435. Necessary Elements of Automobiles, 44. " Never Miss " Starting System, 652. Noisy Action of Planetary Gearing, 761. Xoisy Power Plant, Causes of, 754. Number of Speeds in Sliding Gearsets, Oak Tanned Leather for Clutches, 458. Obtaining Gasoline for Priming Cylin- ders, 739. Obtaining Varying Car Speeds with Friction Gears, 715. Off-Set Crankshafts, 155. Off-Set Cylinder Advantages, 154. Oil Distribution by Manifold, 428. Oil Distribution by Pressure, 430. Oil Distribution Methods, 424. Oil Pump Forms, 423. Oil Spots on Clothing, Removal of, 740. 808 Index Oil Spots, Preparations for Removing, 741. Oiling Devices, Requirements of, 420. Oiling Methods, Individual Pumps, 431. Oiling Methods, Mechanical, 423. Oiling, Suggestions for, 733. Oiling Systems, Constant Level Splash, 425. Oiling Systems, Defects of, 753. Oils, Derivation and Use, 417. Oils for Cooling Systems, 738. One Piece Camshafts, 226. One Piece Connecting Rod, 222. One Piece Steel Valve, 171. Opening Inlet Valve, 203. Operating Front Wheel Brake, 576. Operating Means for Ring Valves, 195. Operating Sliding Gearsets, 724. Operation of Cone Clutches, 460. Operation of Cooling Group, 437. Operation of Differential Piston En- gine, 135. Operation of Friction Clutches, 457. Operation of Friction Transmission, 477. Operation of Igniter Plate, 391. Operation of Individual Clutch Gear- set, 724. Operation of Planetary Gearing, 481. Operation of Selective Sliding Gear- set, 724. Operation of Sliding Gearsets, 490. Operation of Three-Port Two-Cycle Engine, 134. Operation of Two-Port Two-Cycle En- gines, 130. Operation of Valves, 174. Oscillating Wristpin Design, 218. Outer Casing, How to Remove, 626. Outer Casing, Loosening from Rim, 626. Overheating Caused by Rich Mixture, 754. Packing Small Spare Parts, 705. Parts and Functions of Magneto, 785. Parts of Automobile Power Transmis- sion System, 454. Parts of Dry Battery, 356. Parts of Ignition Magneto, 394. Parts of Pressed Steel Frames, 523. Parts of Simple Electric Cell, 355. Parts of Simple Ignition System, 373. Parts of Spark Plugs, 378. Parts of Two-Cycle Engines, 130. Peerless Carburetor Construction, 309. Peerless Cars, Gear Shifting Method, 725. Petroleum Distillates, 265. Peugeot Rear Axle, 568. Pierce-Arrow Cars, Control System of, 724. Pierce Carburetor Construction, 306. Pinching Inner Tubes, 637. Piston, Construction of Differential Type, 135. Piston, Design of Differential Type, 215. Piston, Functions of, 103. Piston Rings, Concentric, 219. Piston Rings, Construction of, 218. Piston Rings, Eccentric, 219. Piston Rings, Functions of, 218. Piston Rings, Methods of Joining, 219. Piston Speed, Definition of, 153. Piston Speed, Safe Limit of, 153. Piston, Two-Cycle, 214. Piston, Two-Diameter, 215. Piston Valves, Hewitt, 197. Pistons, Construction of, 214. Planetary Change Speed Gear, Control of, 717. Planetary Gearing, Advantages of, 485. Planetary Gearing, All Spur Type, 483. Planetary Gearing, Operation of, 481. Index 809 Planetary Gearsets, Cause of Noisy Action, 671. Planetary Gearsets, Clutches for, 474. Planetary Gearsets, Defects of, 761. Plug Gaps for Magneto Current, 412. Plunger for Wristpin Retention, 218. Plunger Pump, Oil, 423. Plunders, Valve Operating, 174. Pneumatic Tire Action, 598. Pneumatic Tire Construction, 598. Pneumatic Tires, Air Valve for, 601. Pneumatic Tires, Anti-Skid Treads, 604. Pneumatic Tires, Bolted-on Type, 603. Pneumatic Tires, Clincher Type, 602. Pneumatic Tires, Dunlop Type, 602. Pneumatic Tires, Inner Tube Con- struction, 598. Pneumatic Tires, Methods of Casing Retention, 601. Pneumatic Tires, Non-Skid Chains for, 607. Pneumatic Tires, Outer Casings, 598. Pneumatic Tires, Protectors for, 607. Pneumatic Tires, Quick Detachable, 601. Pneumatic Tires, Repair of, 633. Pneumatic Tires, Rims for, 601. Pneumatic Tires, Troubles of, 601. Poor Carburetor Adjustment, Symp- toms of, 752. Poor Compression, Causes of, 748. Poor Washing Soaps, Effects on Var- nish, 767. Porcelain Insulated Plug, 378. Portable Vulcanizers, Utility of, 634. Poppet Valve Arrangement, Uncon- ventional, 209. Power Needed to Overcome Air Resist- ance, 64. Power Needed to Propel Car, Deter- mination of, 68. Power Plant, Features of Unit Con- struction, 138. Power Plant, Four Point Support, 139. Power Plant Installation, 137. Power Plant Troubles, Location of, 745. Power Stroke, Definition of, 106. Power Transmission by Bevel and Spur Gearing, 568. Power Transmission by Bevel Gearing, 562. Power Transmission by Shafts, 544. Power Transmission by Side Chains, 544. Power Transmission by Worm Gear- ing, 562. Power Transmission Efficiency, 452. Power Transmission, Single Chain, 544. Power Transmission Systems, 544. Preparations for Removing Oil Spots, 740. Preparations for Treatment of Leather, 769. Pressed Steel Frame, 523. Pressed Steel Frame Parts, 523. Preservation of Upholstery, 770. Pressure at End of Compression Stroke, 105. Pressure Feed Oil Systems, 430. Pressure Feed Systems, 277. Primary Cell Wiring Methods, 357. Principles of Carburetion, 272. Principles of Dynamo Action, 363. Principles of Engine Starter, 648. Principles of Motor Cars, 43. Principles of Two-Cycle Engines, 129. Problem of Spring Selection, 525. Producing Acetylene Gas, 69. Production of Electricity by Mechani- cal Means, 363. Progress of Automobile Design, 39. Progressive Sliding Gearset, 490. 810 Index Properties 'of Benzol, 379. Proportions of Air and Gas Mixtures, 273. Proportions of Valves, 170. Protection Casing for Driving Chains, 566. Protectors, Disadvantages of, 607. Protectors for Tires, 607. Pump, Gear for Circulating Oil, 423. Pump, Plunger Type for Oil, 423. Pump Supply System, 279. Punctures, Repair of, 633. Purpose of Differential Gear, 559. Qualities Desired of Lubricants, 416. Rack and Pinion Steering Gears, 535. Radiator Compounds, Anti-Freezing, 735. Radiator Protection by Shield, 739. Radiator Solutions, Calcium-Chloride, 735. Radiator Solutions, Oil, 738. Ratio of Bore and Stroke, 150. Rayner Two-Cycle Motor, 251. Rear Axle and Change Speed Gearing, 503, 505. Rear Axle, Combination Type, 559. Rear Axle, Floating Type, 556. Rear Axle Forms, 556. Rear Axle, Peugeot, 568. Rear Axle, Torbensen, 566. Rear Axle Transmission, Conventional, 505. Rear Axles, " Dead " Type, 556. Rear Axles, "Live" Type, 556. Rear Axles with Double Reduction Gears, 565. Rear End Suspension, 529. Reason for Cooling Systems, 434. Reason for Lubrication of Mechanism, 414. Reasons for Spark Advance, 712. Regulation of Gas Mixture Supply, 295. Regulation of Motor Speed, 610, 711. Removal of Bolted-on Casing, 626. Removing Grease from Running Gears, 767. Removing Outer Casing, 626. Reo Car, Control System of, 729. Repairing Punctures, 633. Repairing Sagging Frame Members, 765. Repair Outfit for Automobiles, 691. Requirements of Carburetor, 274. Requirements of Clutches, 456. Requirements of Oiling Devices, 420. Results of Knight Motor Trials, 128. Retaining Magneto on Base, 407. Retarded Spark, Effect of, 712. Retention of Leather Cone Clutches, 462. Reynolds Rotary Valve Motor, 190. Rich Gas Causes Overheating, 754. Rims, Clincher, 601. Rims, Fisk, 603. Rims, Solid Rubber Tires, 616. Rims, Demountable, 610. Rims, Dunlop, 601. Rims, Quick Detachable, 601. Ring for Wristpin Retention, 216. Ring Valve Operating Means, 195. Ring Valves, Sphinx, 193. Rocker Arm, Valve Operating. 174. Roller Cam Follower, 174. Rope for Motorists, 702. Rope for Motorists, Utility of, 702. Rotary Valve, Double Cone. 191. Rotary Valves, Conical, 190. Rotary Valves, Disc, 190. Rotary Valves, Drum, 190. Rotary Valves, Itala, 187. Index 811 Rotary Valves, Mead, 190. Rotary Valves, Reynolds, 190. Rules for Manipulating Spark Lever, 712. Rules for Obtaining Best Tire Service, 637, Rules for Tire Inflation, 628. Rules for Tire Selection, 628. Running Gears, Removing Grease from, 767. Safe Piston Speed, 153. Sagging Frame Members, Strengthen- ing, 765. Sand Blister, Cause of, 663. S'aurer Economy Carburetor, 315. Schebler Model " E " Vaporizer, 298. Screw and Nut Steering Gear, 537. Scroll Elliptic Springs, 528. Secondary Distributor Action, 370. Sectional Cushion Tire, 615. Selective Sliding Gearset, 492. Selective Sliding Gearset, Advan- tages of. 493. Selective Sliding Gearset, Operation of, 724. Self-Starters for Gasoline Engine, 648. Semi-Elliptic Springs, 527. Separable Head Cylinder Construction, 147. Sequence of Cycles, Four-Cylinder, 112. Sequence of Cycles, Single-Cylinder, 111. Sequence of Cycles, Six-Cylinder, 114. Sequence of Cycles, Three-Cylinder, Sequence of Cycles, Two-Cylinder, 111. Scries Connection for Cells. 358. Set Screws for Wristpin Retention, 216. Shaft Drive from Friction Transmis- sion, 479. Shaft Driving Methods, 544. Shaft Driving Systems, Care of, 764. Shaft for Pump and Timer Drive, 226. Shapes of Connecting Rod Sections, 224. Shield for Radiator Protection, 739. Shock Absorber, Coil Spring, 684. Shock Absorber, Auxiliary Spring Type, 685. Shock Absorbers, Cam and Spring Type, 685. Shock Absorber, Forms of, 684. Shock Absorber, Friction Type, 686. Shock Absorber, Functions of, 684. Shock Absorbers, Oil Check, 686. Shock Absorbers, Rubber Buffer, 684. Side Chain Drive System, 544. Side Chain Drive from Friction Trans- mission, 479. Side Slipping, Cause of, 574. Side Springs, 528. Sight Feed Lubricators, 421. Signals and Alarms, 687. Silent Chain Camshaft Drive, 180. Silenl Chains, Use in Gearset, 487. Simple Battery, Disadvantages of, 359. Simple Electric Cell, Action of, 355. Simple Ignition System, Action of, 374. Simple Ignition System Parts, 373. Simple Spray Carburetor, 282. Simple Storage Cell, Action of, 360. Single Chain Drive, 543, 586. Single-Cylinder Motor, Horizontal, 107. Single-Cylinder Motor, Vertical, 108. Single-Cylinder Sequence of Cycles, 111. Six-Cylinder Engine Ignition System, 389. Six ( 'ylinder Induction Manifolds, 330. Six-Cylinder Motor, Sequence of Cycles, 114. Skew Bevel Drive Gearing, 577. 812 Index Sleeve and Piston Valve Combination, 185. Sleeve Valves, Knight, 123, 184. Slide Valve Motor, Fischer, 211. Slide Valve Motor, Knight, 121. Sliding Gearsets, Design of Four- Speed Type, 497. Sliding Gearsets, Number of Speeds Provided, 493. Sliding Gearsets, Operation of, 490, 724. Sliding Gearsets, Three-Speed Select- ive, 497. Sliding Gearset without Direct Drive, 495. Sliding Gear Transmissions, Defects of, 762. Slip Covers for Upholstery, 770. Slipping of Friction Disc, Prevention of, 761. Small Spare Parts, Packing, 699. Solid Gasoline as Fuel, 271. Solid Rubber Tires, Attachment of, 617. Solid Rubber Tires, Dual Forms, 617. Solid Tire Action, 598. Spacing Magneto Distributor Contacts, 396. Spare Parts for Repairing, 696. Spark Advance, Reasons for, 712. Spark Gap, Function of, 383. Spark Lever Position, Effect on Fuel Economy, 713. Spark Lever Position for Varying Speeds, 713. Spark Lever, Rules for Manipulating, 712. Spark Plug Design, 378. Spark Plug, Functions of, 30. Spark Plug Parts, 378. Spark Plug, Waterproof Connection, 384. Spark Plugs, Air Gap for Magneto Current, 412. Spark Plugs, Combined with Glass Insets, 384. Spark Plugs, Combined with Relief Cock, 382. Spark Plugs, Defects, 750. Spark Plugs, for Two-Spark Ignition, 385. Spark Plugs, Installation of, 381. Spark Plugs, Two-Pole, 386. Speed Measuring Devices, 688. Speedometer, Centrifugal Type, 690. Speedometer Forms, 688. Speedometer Operating Principles, 689. Sphinx Ring Valve Motor, 193. Spinning of Clutch Cones, 466. Spot Removing Preparations, 740. Spray Xozzle Forms, 293. Squeaking Sounds, Causes of, 755. Spring Attachment to Axles, 531. Spring Attachment to Frames, 531. Spring Selection, Problem of, 525. Spring Shackles, Functions of, 528. Spring Wheel Forms, 594. Spring Wheels, Disadvantages of, 596. Spring, Alloy Steel, 531. Springs, Compound Forms, 533. Springs, Full Elliptic, 527. Springs, Helical Coil, 533. Springs, Influence on Traction Resist- ance, 531. Springs, Laminated Leaf, 526. Springs, Scroll-Elliptic, 528. Springs, Semi-Elliptic, 527. Springs, Side, 528. Springs, Three-Quarter Elliptic, 528. Stability, Influence of Center of Grav- ity, 521. Stamped Metal Wheels, 591. Starters, Air, 651. Starters for Automobile Engines, 648. Starters, Ignition, 650. Starters, Mechanical, 649. Starting Automobile Power Plant, 708. Index 813 Starting Car with Selective Gearing, 727. Starting Crank, Method of Using, 709. Starting Gasoline Engine by Air, 651. Starting Gasoline Engine on Cold .Morning, 738. Starting Multi-Cylinder Engines, 709. Starting System, Cadillac, 655. Starting System, Chalmers, 653. Starting System, Janney-Steinmetz, 652. Starting System, " Never Miss," 652. Starting Systems, Electrical, 654. Starting Systems, One Unit, 657. Starting Systems, Two Unit, 661. Steam Car, Advantages of, 37. Steel Tubing, Use in Frames, 522. Steering Animal Drawn Conveyance, 533. Steering Connections, Care of, 764. Steering Gear Action, 535. Steering Gears, Adjustment for Wear, 538. Steering Gears for Automobiles, 535. Steering Gears, Hand Wheel Move- ment, 539. Steering Gears, Irreversible, 535. Steering Gears, Mounting of Control Levers, 541. Steering Gears, Rack and Pinion, 535. Steering Gears, Screw and Nut, 537. Steering Gears, Use of Ball Thrust Bearings, 541. Steering Gears, Utility of Eccentric Bushings, 538. Steering Gears, Worm and Worm Gear, 535. Steering Knuckles, Elliot Type, 543. Steering Knuckles, Mercedes, 543. Steering Knuckles, Utility of, 535. Steering Mechanism, Back Lash in, 766. Stone Bruise in Tires, 632. Stopping Car with Selective Gearing, 728. Storage Battery Action, 359. Storage Battery Construction, 360. Storage Battery, Current Strength, 362. Storage Battery for Automobile Work, 361. Storage Cell, Action of Simple Type, 360. Storage of Liquid Fuel, 277. Straight Line Shaft Drive, 546. Stream Line Body Design, .67. Strength of Valve Springs, 182. Strength of Wire Automobile Wheels, 592. Strokes, Actual Duration of. 115. Stromberg Double Jet Carburetor, 313. Suggestions for Oiling, 7.33. Summary of Valve Operation Meth- ods, 178. Supplies for Motor Car Maintenance, 698. Supplies, Method of Carrying, 702. Supplies, Miscellaneous, 701. Supplying Kerosene by Direct Injec- tion, 324. Suspension of Frame, 525. Suspension of Front End, 528. Suspension of Rear End, 529. Symptoms Denoting Defective Car- buretion, 752. Symptoms of Poor Carburetor Adjust- ment, 752. Tests for Acid in Calcium Chloride Solution, 736. Tests for Battery Capacity, 749. Tests of Knight Motor, 128. T Head Cylinder Construction, 161. Theory of Cylinder Cooling, 435. Theory of Induction Coil Action, 375. 814 Index Theory of Lubrication, 416. Theory of Thermo-Syphon Cooling System, 439. Thermo-Syphon Cooling Systems, 439. Threaded Plugs for Wristpin Reten- tion, 216. Three Bearing Four-Cylinder Crank- shafts, 231. Three-Cylinder Motor, Sequence of Cycles, 112. Three-Plate Clutch Construction, 467. Three-Plate Clutch with Brake, 470. Three- Point Support Advantages, 138. Three-Port Two-Cycle Engine Opera- tion, 134. Three-Quarter Elliptic Springs, 528. Three-Quarter Scroll Elliptic Springs, 528. Three-Speed Selective Sliding Gear- set, 497. Three-Wheel Tractor, 75. Tie Bar, Functions of, 475. Time of Ignition, 205. Timer and Distributor Forms, 367. Timer and Pump Drive Shaft, 226. Timer, Four-Cylinder Types, 370. Timer, Touch Contact, 369. Timer, Wipe Contact, 369. Timers, Arrangements of Contacts, 372. Timers or Distributors, Defects of, 750. Timers, One-Cylinder Types, 368. Timers, Speed of Rotation, 368. Timing, Fischer Slide Valves, 211. Tire Failure, Causes of, 631. Tire Inflation, Importance of, 630. Tire Inflation Methods, 631. Tire Inflation, Table of Pressure, 630. Tire Manipulation Hints, 624. Tire Irons, Forms of, 621. Tire Irons, Use of, 621. Tire Protectors, 607. Tire Repair Outfit, 624. Tire Restoration, Supplies for, 619. Tire Restoration, Tools for, 619. Tire Size, Table for Selection, 629. Tire Sizes and Axle Loads, 629. Tires for Automobiles, 596. Tool Roll and Tool Assortment, 691. Tools and Miscellaneous Equipment, 691. Tools for Mechanically Fastened Tires, 626. Tools, Use and Care of, G93. Torbensen Rear Axle, 566. Traction Resistance, Influence of Springs, 531. Tractor, Three Wheel, 75. Tractor, Four Wheel, 83. Tractor, Agricultural, 97. Tractor, Hoadley System, 509. Transforming Reciprocating to Rotary Motion, 113. Transmission of Power, 544. Transmission Gear for Four-Wheel Drive, 505, 548. Treads, Anti-Skid, 604. Treads, Raised Type, 604. Treating Leather Tops, 769. Trend of Construction, 40. Troubles in Carburetors, 752. Tubular Front Axle, 541. Tungsten Filament Bulbs, 676. Tungsten Filament, Current Consump- tion of, 676. Two Bearing Four-Cylinder Crank- shaft, 231. i Two-Cycle Cylinder Ports, Function of, 132. Two-Cycle Engine, Differential Piston Type, 135. Two-Cycle Engine Disadvantages, 136. Two-Cycle Engine Parts, 130. Two-Cycle Engines, Principles, 129. Two-Cycle Motor, Air Cooled, 448. Two-Cycle Motor, Amplex, 246. Two-Cycle Motor, Cote, 248. Two-Cycle Motor, Legros, 248. Index 815 Two-Cycle Motor, Rayner, 251. Two-Cycle Piston, 214. Two-Cylinder Motor, Sequence of Cycles, 111. Two-Cylinder Opposed Motor Features, 117. Two-Diameter Piston, 215. Two-Pole Spark Plug, 386. Two-Port Two-Cycle Engine Opera- tion, 130. Two-Spark Ignition System, 385. Two-Speed Axle, 577. Two-Thrown Crankshaft, 230. Types of Change Speed Gearing, 476. Types of Cooling Systems, 435. Types of Crankshafts, 227. Types of Lubricators, 420. Types of Valve Plungers, 174. Typical Engine Stoppage Analyzed, 746. Typical Four-Cycle Power Plants, 253. Typical Front Wheel Brakes, 575. Typical Induction Coil, 375. Typical Magneto Forms, 405. Typical Motor Control System, 710. Typical Valve Timing Diagrams, 206. U Underslung Frame Advantages, 521. Underslung Frames, 521. Unit Power Plant Features, 137. I'pholstery, Preservation of, 770. Upswept Frame Type, 524. Use and Care of Tools, 693. Use of Combined Clutch and Brake Pedal, 730. Use of Cone Brake, 466. Utility of Auxiliary Exhaust Valve, 445. Utility of Change Speed Gearing, 475. Utility of Cut-Out Valve, 338. Utility of Eccentric Bushings, 538. Utility of Friction Pedal, 717. Utility of Gas Engine Valves, 104. Utility of Gasoline Strainers, 319. Utility of Motor Car Brakes, 568. Utility of Windshields, 683. Valve, Bevel Seat, 170. Valve, Cast-Iron Head, 171. Valve Construction, 170. Valve Design, 169. Valve, Electrically Welded, 171. Valve, Flat Seat, 170. Valve for Pneumatic Tires, 601. Valve Head Construction, 171. Valve in the Head Construction, 161. Valveless Miesse Engine, 185. Valve Lifting Cams, 173. Valve Location Features, 160. Valve, One Piece Steel, 171. Valve Operation by Plunger, 174. Valve Operation by Rocker Arm. 174. Valve Operation, Hydraulic, 175. Valve Operation, Indirect, 175. Valve Operation Methods, 174. Valve Operation, Methods Summar- ized, 178. Valve Placing Methods, 161. Valve Plunger Types, 174. Valve Proportions, 170. Valve Springs, Strength of, 182. Valve Timing, Closing Inlet, 204. Valve Timing, Exhaust Closing, 202. Valve Timing, Exhaust Valve Lead, 202. Valve Timing Instructions, 200. Valve Timing, Making Flywheel, 207. Valve Timing, Opening Inlet, 203. Valve Timing, Steps in, 209. Valve Timing, Typical Diagrams, 206. Valves, Concentric Construction, 167. Valves, Darracq, Rotary Distributor, 197. 816 Index Valves, Piston, 185, 197. Valves, Rotary, 187, 190, 191. Valves, Sleeve, 184, 185. Valves, Split Ring, 193. Valves, Utility of, 104. Vaporizing Gasoline, Early Methods, 280. Varnish Deterioration Because of Poor Washing Soap, 767. Varnish Deterioration, Effect of Am- monia Fumes, 768. Venturi Tube Action, 290. Vertical Single-Cylinder Motor, 108. Vibrator, Action of, 775. Vigrator Coil Defects, 751. Voltage, Definition of, 358. Voltage Required for Ignition, 362. Vulcanizers, Acid Cure, 624. Vulcan Electric Gearshift, 742. Vulcanizers, Electrical, 635. Vulcanizers, Method of Using, 635. Vulcanizer, Vapor, 635. Vulcanizing, Temperatures for, 635. W Wagon Brake Form, 568. Water Circulating Pumps, 438. Water Circulation, Impediments to, 754. Water-Cooled Mufflers, 336. Water Cooling by Forced Circulation, 435. Water Cooled by Natural Circulation, 435. Water Cooling Methods, 435. Waterproof Spark Plug Connection, 384. Watt, Definition of, 358. Wheels, Detachable, 638. Wheels, Rudge-Whitworth, 638. Wick Carburetor Action, 280. Wick, Carburetor, Lanchester, 284. Windshields, Construction of, 684. Windshields, Glass, 684. Windshields, Leather and Celluloid, 683. Windshields, Utility of, 683. Winter Care of Automobiles, 735. Winter Care of Lubricating System, 738. Wire Automobile Wheels, 588. Wire Automobile Wheels, Strength of, 592. Wire for Magneto Ignition Systems, 412. Wire Wheels, Disadvantages of, 592. Wiring, Defects of, 751. Wiring Diagram, Four-Cylinder Double System, 411. Wiring Diagram of Low Tension Sys- tem, 391. Wiring of Battery Ignition Systems, 388. Wiring Systems, High Tension Mag- neto, 398. Wiring System, Transformer Coil Magneto, 400. Wood Automobile Wheels, 588. Wooden Wheels, Artillery Hub, 588. Wooden Wheels, Savern Hub, 588. Wood Frames, 522. Worm and Worm Gear Steering, 535. Worm Gear Driving, 562, 583. Worm Gearing, Advantages, of, 564. Worm Gearing, Efficiency of, 564. Wristpin, Functions of, 216. Wristpin Retention by Plunger, 218. Wristpin Retention by Ring, 216. Wristpin Retention by Set Screw, 216. Wristpin Retention by Threaded Plugs, 216. Wristpin Retention of, 216. Yearly Output of Automobiles, 35. Z Zenith Double Jet Carburetor, 317. PRACTICAL SCIENTIFIC TECHNICAL EACH BOOK IN THIS CATALOGUE IS WRITTEN BY AN EXPERT AND IS WRITTEN SO YOU CAN UNDERSTAND IT THE NORIAN I HENLEY PUBLISHING COMPANY Publishers of Scientific and Practical Books 132 Nassau Street New York, U. S. A. Any book in this Catalogue tent prepaid on receipt of price. University of California SOUTHERN REGIONAL LIBRARY FACILITY 305 De Neve Drive - Parking Lot 17 Box 951388 LOS ANGELES, CALIFORNIA 90095-1388 Return this material to the library from which it was borrowed. 000 624 792 7