in·ter·nal-com·bus·tion engine (ĭn-tûrnəl-kəm-bŭschən)
n. An engine, such as an automotive gasoline piston engine or a diesel, in which fuel is burned within the engine proper rather than in an external furnace, as in a steam engine.

internal-combustion engineone cycle of a four-stroke diesel engine
A. intake stroke
B. compression stroke
C. power stroke
D. exhaust stroke