The Wankel Rotary Piston Engine

The Wankel is the first of many rotary piston designs to have challenged the dominance of the reciprocating piston engine for small power units. Compared with the reciprocating internal-combustion engine, it offers reduced size, weight, vibration, noise and production costs, combined with comparable thermal efficiency. Commercial production was started by N.S.U. Motorenwerke in Germany and Toyo Kogyo in Japan in 1967 as a petrol engine for cars; a joint N.S.U.-Citroen car will follow later. The engine is also suitable for industrial, marine or aeronautical uses, and there is much interest in possible diesel and multi-fuel versions. Sixteen European, American and Japanese companies held licences to build the engine by January 1968.