Internal combustion engines

Publisher Summary This chapter discusses the internal combustion engines. In a steam engine, the working substance—that is steam—receives heat energy from a fuel burnt in a furnace, which may be sited at some considerable distance from the engine. Such an engine may be referred to as an external combustion engine. Space and weight may be saved if the fuel is made to give up its heat energy to the working substance by burning inside the cylinder and the engine is then known as an internal combustion engine. This cycle of operations may occur while the piston completes four strokes, in which case the engine is known as a 4-stroke engine, or the cycle may occur while the piston completes only two strokes, in which case the engine is known as a 2-stroke engine. In its simplest form, the gas turbine unit consists of an air compressor, a combustion chamber, and a turbine. Air is drawn from the atmosphere into a rotary compressor where it is compressed to a high pressure before passing to a combustion chamber where it is heated by the internal combustion of the fuel. The hot gases at high pressure then pass to the turbine.