external combustion engine

{{Redirect|External combustion|the album|External Combustion}}

{{Short description|Type of reciprocating heat engine}}

File:Stirling Engine.jpg, with external heat from a spirit lamp (bottom right) applied to the outside of the glass displacer cylinder.]]

File:Newcomen atmospheric engine animation.gif, a precursor of the steam engine, with the boiler heated from beneath]]

File:Cutaway steam locomotive.jpg. Although the fire is within an enclosed firebox, this is still an external combustion engine, as the exhaust gas and the steam working fluid are kept separate.]]

{{Seriesbox aircraft propulsion}}

An external combustion engine (EC engine) is a reciprocating heat engine where a working fluid, contained internally, is heated by combustion in an external source, through the engine wall or a heat exchanger. The fluid then, by expanding and acting on the mechanism of the engine, produces motion and usable work.[http://www.merriam-webster.com/dictionary/external%20combustion external combustion - Definition from the Merriam-Webster Online Dictionary] The fluid is then dumped (open cycle), or cooled, compressed and reused (closed cycle).

In these types of engines, the combustion is primarily used as a heat source, and the engine can work equally well with other types of heat sources.