In common usage, an engine burns or otherwise consumes fuel, and is differentiated from an electric machine (., electric motor) that derives power without changing the composition of matter.[3] A heat engine may also serve as a prime mover, a component that transforms the flow or changes in pressure of a fluid into mechanical energy.[4] An automobile powered by an internal combustion engine may make use of various motors and pumps, but ultimately all such devices derive their power from the engine
