Piston Engine Operation and Construction

The piston engine is an internal combustion engine working on the principle devised by Dr. Otto

in

1876. The piston engine converts chemical energy in the form of petroleum fuel into

mechanical energy via heat and can be termed a heat engine. The working medium is air, which

is capable of changes in volume and pressure when subjected to an increase in temperature

caused by the burning fuel.

The working cycle consists of four strokes of the piston: Induction, Compression, Power, and

Exhaust. This is known as the four-stroke or Otto cycle. The cycle is of an intermittent nature;

each stroke is distinct and separate from the others. During each cycle, the piston moves in a

reciprocating motion within a tube termed a cylinder barrel. The crankshaft converts this linear

motion into a rotary motion. In one four-stroke cycle, the crankshaft makes two complete

revolutions -

720°.