The Wankel engine is a type of INTERNAL COMBUSTION ENGINE. It was invented by the German engineer, the up and down motion of the pistons has to be converted into a rotary and wheels could be simplified if the pistons themselves rotated. In the Wankel engine, a triangular piston rotates inside a chamber shaped like an eight. As it rotates, FUEL and air are sucked in through a valve, compressed and ignited by an electrical spark. The burning gases expend rapidly and drive the piston round.