noun
external combustion engine
Technical term for an engine where fuel combustion occurs outside the working fluid, such as a steam engine or Stirling engine.
蒸気機関は外燃機関の一種です。
A steam engine is a type of external combustion engine.
内燃機関 is an internal combustion engine, where fuel burns inside the engine itself (e.g., car engine). 外燃機関 is the opposite, with combustion outside.
Compound of 外 (outside), 燃 (burn), and 機関 (engine). A straightforward technical term formed from kanji components.