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 …showed first 75 words of 1385 total…

…showed last 75 words of 1385 total…An internal-combustion engine must also have some kind of transmission system to control and direct the mechanical energy where it is needed; for example, in an automobile the energy must be directed to the driving wheels. Since these engines are not able to start under a load, a transmission system must be used to 'disengage' the engine from the load during starting and then to apply the load when the engine reaches its operating speed.