internal-combustion engine (ĭn-tûr'nəl-kəm-bŭs'chən) An engine whose fuel is burned inside the engine itself rather than in an outside furnace or burner. Gasoline and diesel engines are internal-combustion engines, as are gas turbine engines such as turbojets. Compare steam engine. |
Any engine powered by burning fuel inside it (for example, a standard automobile engine). Internal-combustion engines normally burn fossil fuels and therefore are a major source of air pollution. (See smog.)