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 vehicles use a piston engine similar to the one-cylinder, four-stroke motor in the first car ever made, Karl Benz's Patent Motorwagen. Lately, a more fuel-efficient and emissions-friendly engine ...