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 ...

Modern internal combustion engines — including those that run on diesel fuel — require a lot of special parts and systems to prevent dumping excess emissions into the atmosphere. Not only are those ...

Last month's "How It Works" story gave you the basics of the four-stroke cycle, describing the motion of the intake and exhaust valves in relation to the piston moving up and down in the cylinder.