Editing External combustion engine (section)

{{Redirect|External combustion|the album|External Combustion}}
{{Short description|Type of reciprocating heat engine}}
[[File:Stirling Engine.jpg|thumb|Model [[Stirling engine]], with external heat from a [[spirit lamp]] (bottom right) applied to the outside of the glass displacer cylinder.]]
[[File:Newcomen atmospheric engine animation.gif|thumb|upright|[[Newcomen engine|Newcomen's engine]], a precursor of the [[steam engine]], with the boiler heated from beneath]]
[[File:Cutaway steam locomotive.jpg|thumb|Sectioned [[steam locomotive]]. Although the fire is within an enclosed [[firebox (steam engine)|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 engine|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 (engineering)|mechanism]] of the engine, produces motion and usable [[Mechanical work|work]].<ref>[http://www.merriam-webster.com/dictionary/external%20combustion external combustion - Definition from the Merriam-Webster Online Dictionary]</ref> 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.