The other parts of an automobile which need a brief description are the starting handle, the carbureter, silencer, governor, magneto, and gears.
Starting Handle. - In front of the car there is a handle attached to a tube which terminates in a clutch. A powerful spring keeps this clutch from a second one that is keyed to the engine shaft. When one desires to start the engine he presses the handle towards the right, so as to bring the clutches together and turns the handle in the direction of the hands of a clock. When the engine begins to fire the clutches slip over one another.
FIG. 179. - Valves and Valve Cages. Showing how they may be removed.
Carbureter. - The carbureter (Fig. 183) reduces the liquid fuel to a fine spray and mixes it with sufficient quantity of air so that it will burn. It consists of two parts - a device for regulating the supply of fuel called the float chamber, and a device for controlling the amount of air to be mixed with the liquid spray.
Fig. 180. - Ignition Apparatus for a Gas Engine. The illustration to the left shows the interior with four dry cells and a spark-coil. The illustration to the right shows the waterproof case, switch, and necessary wiring.
Silencer. - As the products of combustion are given off at high pressure they expand violently and cause a vacuum in the exhaust pipe. The air rushes back with terrific force (15 lbs. per square inch) causing a loud noise. To overcome this noise, a device called a silencer is fitted to the machine which allows the gas to escape gradually, or reduces it to atmospheric pressure so that the noise becomes a gentle hiss.
Brakes. - There are usually two brakes on each car - a side hand-lever that acts on the axle of the driving wheel and another, operated by the foot, that acts on the transmission gear.
Governor. - The speed of the engine may be regulated in three ways by a centrifugal ball governor. When the speed exceeds a certain limit it either raises the exhaust valve so that no fresh charges are drawn in, prevents the opening of the inlet valve, or throttles the gas supply. The last arrangement is the one most commonly employed.
Gear-Box. - The gear-box of a motor car is very important. An explosion engine must be run at a high speed to develop its full power. There are times when a machine must do heavier work than usual, as for example, when it passes from a level road to a steep hill. It accomplishes this task by altering the speed ratio of the engine to the driving wheel. This change in the speed ratio is made possible by the mechanism of the gear-box.
Spark-Plug. - An accumulator and induction coil is an arrangement for producing a spark. It consists of a disk of insulating material mounted on a cam or half-speed shaft with a piece of brass, called a contact piece, attached. A
Fig. 181. - Electrical Gas Engine. Notice the two fly-wheels and the pulley attached on the left. Power is transmitted from the pulley by means of belting.
Fig. 182. - Chassis of a Motor Car.
A - Front Axle
B - Engine
C - Fly-Wheel Clutch
D - Frame
F - Driving Shaft
G - Universal Joint H - Silencer
I - Change Speed Gearing K - Rear Axle (live) L - Housing
M - Differential Gear N - Car Springs O - Brake P - Rear Axle movable plate rotates and presses against the disk. When this contact takes place a current flows from the accumulator through the different parts, including the induction coil, and back to the accumulator. In this circuit is a spark plug so arranged that there is a small gap through which the current passes and produces a spark.