starts with the piston at the top of the cylinder (TDC) and the intake valve open to admit air and fuel. At bottom-dead-center (BDC) the inlet valve is closed and the compression stroke (b) starts.

This means that the high torque efficiency of the two-stroke engine is kept, while the cleanliness and longevity of the four-stroke engine is gained. A win-win scenario. What’s more, the exhaust ...

Six-stroke engines are having a moment. Porsche made waves last year for patenting a six-stroke powerplant that promised more efficiency and power by using a funky planetary gearset attached to the ...