LIST OF ILLUSTRATIONS
| FIG. | PAGE | |
| 1. | Engine Actions | [3] |
| 2. | Gasoline Engine Cycle | [7] |
| 3. | Gasoline Engine in Section | [21] |
| 4. | Crank Shafts | [22] |
| 5. | One-Throw Crank Shaft | [23] |
| 6. | Connecting Rod | [23] |
| 7. | Piston and Piston in Section | [24] |
| 8. | Piston Rings | [24] |
| 9. | Conical Valve Seat | [25] |
| 10. | Automatic Inlet Valve in Cage | [25] |
| 11. | Cam Action | [27] |
| 12. | Four Arrangements of Valves | [29] |
| 13. | Circulation of Cooling Water | [31] |
| 14. | Types of Pumps | [32] |
| 15. | Radiator Constructions | [33] |
| 16. | Radiator and Fan | [33] |
| 17. | Engine Arrangements Showing Order of Firing | [40] |
| 18. | Two-Cycle Engine | [48] |
| 19. | Carburetor Principles | [54] |
| 20. | Automatic Carburetors | [59] |
| 21. | Mechanically Controlled Carburetor | [63] |
| 22. | Float-Feed Carburetor with Gravity Gasoline Feed | [65] |
| 23. | Pressure-Feed Gasoline System | [67] |
| 23A. | Types of Float Valves | [69] |
| 23B. | Types of Auxiliary Air Inlets | [71] |
| 24. | Battery Connections | [85] |
| 25. | Make-and-Break Ignition | [92] |
| 26. | Types of Timers | [99] |
| 27. | Mechanical Vibrator | [104] |
| 28. | Magnetic Vibrator | [104] |
| 29. | Spark Plug and Spark Plug in Section | [107] |
| 30. | Ignition Circuit | [108] |
| 31. | Friction Cone Clutches | [115] |
| 32. | Multiple-Disk Clutch | [117] |
| 33. | Sliding Gear—Progressive Type | [122] |
| 34. | Selective Type | [127] |
| 35. | Planetary Type | [133] |
| 36. | Individual Clutch and Friction Drive | [139] |
| 37. | Propeller and Single-Chain Drives | [143] |
| 38. | Typical Universal Joint | [144] |
| 38A. | Types of Shaft Drives | [145] |
| 39. | Live Axle—Non-floating Type | [147] |
| 40. | Live Axle—Floating Type | [147] |
| 40A. | Dead Axle with Driving Shaft | [149] |
| 41. | Torsion Rod | [150] |
| 42. | Double Side-Chain Drive | [151] |
| 43. | Differentials | [154] |
| 44. | Two Arrangements of the Drag Link | [162] |
| 45. | Steering Principles | [163] |
| 46. | Steering Mechanisms | [165] |
| 47. | Three Varieties of Brakes | [168] |
| 48. | Springs | [175] |
| 49. | Distance or Radius Rods | [177] |
| 50. | Jump-Spark Wiring Diagrams | [237] |
| 51. | Jump-Spark Wiring Diagrams | [239] |
| 52. | Make-and-Break Wiring Diagram | [241] |
| 53. | Make-and-Break Wiring Diagram | [241] |
ILLUSTRATIONS IN APPENDIX
| 1. | Magnetic Lines of Force | [250] |
| 2. | Armature | [256] |
| 3. | The Armature and Lines of Force | [256] |
| 4. | The Armature and Lines of Force | [257] |
| 5. | The Armature and Lines of Force | [257] |
| 6. | The Armature and Lines of Force | [258] |
| 7. | The Armature and Lines of Force | [259] |
| 8. | Make-and-Break System | [271] |
| 9. | Eisemann Ignition System | [285] |
| 10. | Wiring Diagram, H.-T. Magneto Interchangeable with Secondary Coil | [298] |
| 11. | Wiring Diagram, Two-Spark Magneto | [302] |
| 12. | Timing Diagram, Two-Spark Magneto | [304] |
| 13. | Diagrams showing Position of Shield Revolving about Armature | [309] |
| 14. | Wiring Diagram, Four-Spark Magneto | [312] |
| 15. | Timing Diagram, Four-Spark Magneto | [314] |
| 16. | Bosch Jump-Spark Dual System | [318] |
| 17. | Remy Inductor | [321] |
| 18. | Inductor Giving Six Waves | [321] |
| 19. | Magnetic Igniter | [324] |
| 20. | Wiring Diagram of Magnetic Igniter System | [324] |
MOTOR-CAR PRINCIPLES
CHAPTER I
GASOLINE ENGINE PRINCIPLES
The action of a steam, gasoline, or hot-air engine depends on the principle that when air or other gas is heated it expands, and that if it is confined in a space that will not permit it to expand, in striving to do so it creates pressure against all parts of the chamber in which it is contained. The more a gas is heated, the more it will expand if it is free to do so, and if not free, the greater will be the pressure that it will exert in striving to expand. Pressure may thus be generated by heat, and following along similar lines, heat may be produced by pressure, for when the pressure of a gas is increased by compressing it, or forcing it to occupy a smaller space, the gas will become heated. The reverse is also true, that when a gas is cooled, its volume is reduced, which reduces the pressure that it exerts; similarly, reducing the pressure by permitting the gas to expand reduces its temperature.
To state these principles in another form, to create pressure in a gas it must either be heated or compressed into a smaller space, and to reduce its pressure it must either be cooled or permitted to expand.
The action of a locomotive, the most familiar type of steam engine, is no mystery, and the production of steam in the boiler, its passage to the cylinder, and the application of its steady pressure against first one side of the piston and then the other, resulting in the turning of the driving wheels, are well understood. Water being converted into steam in the boiler, pressure is created because of the tendency of the steam to expand, but the only place in which it may expand is the cylinder, where in so doing it moves the piston.
Fig. 1.—Engine Actions.
A gasoline engine is similar to a steam engine in that its piston is moved by the pressure exerted by a heated and expanding gas; it is different in that the pressure is produced inside of the cylinder by the combustion of an inflammable mixture of gasoline vapor, instead of being generated in a boiler away from the cylinder. The heat of the combustion creates great pressure, and as the piston is the only part that can give before it, it is moved from one end of the cylinder to the other, this motion being utilized in the turning of the crank shaft. The combustion, which is so rapid that the generally accepted term for it is explosion, can occur only after the mixture has been drawn into the cylinder, and so prepared that it ignites quickly and burns completely, with the object of obtaining the greatest possible heat from it in the shortest possible time. In order that one explosion may be followed by another, the burned and useless products of combustion must be expelled to make place for a fresh charge of the inflammable mixture.
These successive events, forming a cycle, must be performed as long as the engine runs, and the constantly changing pressure in the cylinder due to the movement of the piston allows a fresh charge to enter, prepares it, and expels the products of combustion after the pressure that they have exerted has been utilized.
While in the great majority of steam engines the steam acts first on one side of the piston and then on the other, in an automobile gasoline engine the pressure is exerted on only one side, the combustion of the mixture taking place between the piston and the closed end, or head, of the cylinder. The other end of the cylinder is open, and the piston slides between the ends, its movement from one end to the other, called a stroke, corresponding to a half revolution of the crank shaft.
Gasoline engines are divided into two classes, according to the number of strokes of the piston that are necessary to accomplish the cycle; in the most usual type, four strokes are necessary, the class being called the four-stroke-cycle, or four-cycle, in distinction to the two-stroke-cycle, or two-cycle, in which but two strokes are necessary.
Of the five events that compose the cycle, three (the inlet, during which the fresh mixture enters the cylinder, its compression or preparation, and the exhaust of the burned gases) are performed by the piston; during the power event the piston is moved by the pressure resulting from the combustion, while the combustion event is due to an outside source. In the four-cycle type of engine, which is in almost universal use for automobiles, the events are considered with reference to the movement made by the piston during which they are performed, and may be called the inlet, compression-combustion, power, and exhaust strokes. In order that the engine may continue to run, it is obvious that the events must be performed in the correct order, and that the failure of one will affect all the others.
During the inlet stroke, a charge of fresh mixture enters the cylinder as the piston makes an outward stroke from the closed toward the open end. When the piston makes the following inward stroke, the mixture is compressed and combustion occurs, the pressure from which drives the piston outward on the power stroke. This is followed by another inward stroke, which pushes the burned gases out of the cylinder. It will be seen that power is developed during only one stroke of the four, the other three being required in the preparation for the following power stroke. The movement of the piston over these three dead strokes is secured by attaching to the crank shaft a heavy fly wheel, the momentum of which, acquired during the power stroke, keeps the crank shaft revolving and the piston in motion while the events are performed.
Fig. 2.—Gasoline Engine Cycle.
The space between the piston and cylinder head in which the combustion occurs is called the combustion space, and the inlet and exhaust valves open into it, the first being that by which the fresh mixture enters, and the second that by which the products of combustion escape. The device for igniting the mixture projects into the combustion space, and the means of ignition in universal use for automobile engines is an electric spark.