ABSTRACT

The modern motor vehicle engine burns a fuel to obtain power. The fuel is usually petrol (gasoline) or diesel, although liquid petroleum gas (LPG) and compressed natural gas (CNG) are sometimes used. Specialist fuels have been developed for racing car engines. Towards the end of the compression stroke, the fuel is ignited and burns to give a large pressure rise in the cylinder above the piston. Valve overlap helps clear remaining exhaust gases from the combustion chamber. The camshaft rotates once for the two revolutions of the crankshaft during the four-stroke cycle. The drive from the crankshaft to the camshaft has a 2:1 ratio produced by the numbers of teeth on the driven and driver gears. During the downwards movement of the piston, the hot expanding gases are forcing the piston down the bore, producing torque at the crankshaft. This is the expansion process. The mounting system has to isolate the vehicle from the engine vibrations.