An internal-combustion engine is a heat engine that burns fuel and air inside a combustion chamber located within the engine proper. Simply stated, a heat engine is an engine that converts heat energy to mechanical energy. The internal- combustion engine should be
distinguished from the external- combustion engine, for example, the steam engine and the Stirling engine, which burns fuel outside the prime mover, that is, the device that actually produces mechanical motion. Both basic types produce hot, expanding gases, which may then be employed to move pistons, turn turbine rotors, or cause locomotion through the reaction principle as they escape through the nozzle.
Most people are familiar with the internal-combustion reciprocating engine, which is used to power most automobiles, boats, lawn mowers, and home generators. Based on the means of ignition, two types of internal-combustion reciprocating engines can be distinguished:
spark-ignition engines and compression-ignition engines. …
