A major improvement over the piston-driven internal-combustion engine [IV], the Wankel engine was developed over the early 1950s and perfected in 1956 by Felix Wankel (1902–1988). Wankel was a German engineer who sought for many years to find a way to harness internal
combustion without the necessity of transforming linear motion into rotary motion, a major source of the inefficiency of piston-driven internalcombustion engines. Wankel began working on the concept of a rotary engine in 1924. He formed his own engineering company in the 1930s and worked for the German Air Ministry during World War II. Following the war he worked on the engine design at his own risk. He began in 1945 with a pump design, improving it by trial and error. When he sought a patent, he discovered that some elements of his final design had been tried out previously in Sweden, France, and Switzerland.
His revolutionary solution to the internal-combustion chamber was a lighter and more efficient engine. Inside a cylinder, a triangular-shaped rotor rotates around a central axis. The engine can fire three times on each rotation, allowing the engine to do three times as much work as a conventional piston engine with the same internal engine volume. The rotor itself serves to clear the intake and exhaust openings, removing the necessity for valves and the complex camshaft drive for the valve mechanism. In some of Wankel’s designs the outside casing would rotate in one direction while the rotor rotated in the opposite direction. However, in the automotive application, Wankel decided on a stationary casing.
The Wankel engine operates at high efficiency and at very high revolutions per minute, up to 17,000. A number of manufacturers bought the rights to the Wankel design. Mazda was the first to introduce a production car powered with the new engine, in 1968. Its smooth operation at high speed won it praise from automotive journalists and observers. However, difficulties with worn seals and the lack of mechanics trained to repair the engines worked against their commercial success.