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 ...
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How the Atkinson cycle works - car engines

How does a hybrid car engine work? The modern Atkinson cycle is used by cars such as the Toyota Prius, Ford C-max and Fusion ...