Practical Hand Book of Gas, Oil and Steam Engines / Stationary, Marine, Traction; Gas Burners, Oil Burners, Etc.; Farm, Traction, Automobile, Locomotive; A simple, practical and comprehensive book on the construction, operation and repair of all kinds of engines. Dealing with the various parts in detail and the various types of engines and also the use of different kinds of fuel.

by John B. Rathbun

In the majority of cases the crank revolves, while the cylinder stands still, but in some of the recently developed aeronautic motors this is reversed, the cylinders revolving with the crank stationary. The relative motion, however, is the same in both cases.

(6.) The CRANK SHAFT, of which the crank is an integral part, transmits the rotary motion of the crank to the driving pulley.

(7.) The admission and release of the gases to and from the cylinder are controlled by the INLET VALVE and EXHAUST VALVE, respectively, in a four stroke cycle engine.

The valves are merely gates, allowing the gas to flow, or stopping it, at the proper intervals, depending on the event taking place at that time in the cylinder.

In the two stroke cycle engine there are no valves, the admission and release of the gas being controlled by the position of the piston, and the openings cut in the cylinder walls.

6. IGNITION or the firing of the combustible charge is accomplished by the IGNITION SYSTEM. In most modern engines the mixture is ignited when it is under the greatest pressure or at the end of the stroke.

For maximum efficiency the mixture should be ignited when it is under the greatest pressure or compression. The time at which ignition occurs is also controlled by the ignition system.

7. The GOVERNOR regulates the speed of the engine; either by changing the richness of the mixture, by changing the number of working strokes in a given time or by altering the quantity of gas admitted to the cylinder, or sometimes by a combination of these methods.

8. The BELT WHEELS or PULLEYS are the means of transmitting the power of the engine to the work to be performed. The engine is generally connected to the driven machinery by a belt connecting the engine pulley with the pulley of the driven machine.

9. The FLY WHEELS by reason of their mass and their momentum, store up a portion of the energy expended during the working stroke, and return it to the engine in order to carry it through the idle strokes of compression, admission and expulsion. In some engines the fly wheels serve in double the capacity as pulleys.