Rotary engines (also known as Wankel engines and Wankel rotary engines) are quite different from piston or "reciprocating" engines. One of the distinguishing features is that they don't need valves to ...

Most modern gasoline and diesel-powered engines found in the cars and trucks seen on today's roadways rely on the four-cycle-engine principles developed in the late 1800s by Nikolaus Otto, Gottlieb ...