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 ...

If you've ever looked under the bonnet of a car, the engine can seem like a maze of metal parts, pipes and wires. In reality, its job is quite simple: it turns fuel into the power that moves your car.