For slow speed E is stationary; for high speed A and E revolve with the gear C; and for reversing A is locked by means of the brake.
Fig. 62. Frictional Transmission.
Frictional Transmission.—A single illustration will suffice to show the principle involved in Frictional transmission. Fig. 62 represents a driven shaft A, which receives its power from the engine, and on which is mounted a friction wheel B, that is adapted to travel along on the shaft in front of a friction disk C, secured to the transmission shaft D.
The shaft A has a spline E, and means are provided at the end of the wheel B to draw it back and forth on the shaft, the slightest movement toward the center of the friction disk C serving to increase the speed of the driven shaft D.
CHAPTER IX
THE MOTOR
This is a subject so vast and comprehensive, that it will require most careful thought and attention in order to get a working idea of the principle. The greatest refinements are resorted to in the building and handling of engines, and more attention is bestowed on this part of the automobile than on any other feature for the following reason:
Value of Fuel Utilized.—Not more than eighteen per cent. of the value of the fuel is actually utilized. The rest is waste. A gasoline engine is a heat motor,—that is, it derives its power from the expansion of the fuel, and this expansion is produced by the heat.
Now the loss referred to comes about in this way: About 52 per cent. of the loss is taken up by the water which surrounds the engine cylinders; from sixteen to seventeen per cent. escapes at the exhaust; and fifteen per cent. loss is due to conduction and radiation.
The Waste.—The great waste, therefore, lies in the cooling means, which must be employed. The temperature of the ignited gases reaches fully 2200 degrees, which is over ten times the temperature required to convert water into steam.