Wankel Engine

Wankel Engine, internal-combustion engine, powered by gasoline, that uses a triangular-shaped rotor, or rotating part, to produce mechanical energy. Traditional internal-combustion engines use pistons (solid cylinders moving within a closely fitted casing) instead of a rotor. The Wankel engine is powerful for its weight and size, vibrates much less than piston engines, has few moving parts, and can run comparatively quietly and smoothly on different grades of fuel. The engine is named after German engineer Felix Wankel for his contribution to the engine’s development in the 1950s.

The Wankel engine produces rotary motion by directly powering a main driveshaft, instead of powering pistons that indirectly drive a main driveshaft. The rotor of the Wankel engine is encased in an oval-shaped housing. Although all three points of the triangular rotor remain in tight contact with the housing wall, space remains between the sides of the rotor and the housing wall. When the rotor turns, gasoline is pulled into the housing through an intake port and trapped between one side of the rotor and the housing wall. It compresses as the rotor continues to turn. The trapped gas is then carried past a spark plug and ignited, releasing the energy that moves the rotor. The rotor moves the spent gas and air to an exhaust port, sending it quickly out of the housing. Each of the three sides of a Wankel engine’s rotor constantly drives the shaft. When the rotor moves one-third of the distance around its center, the main drive shaft rotates one complete turn.

Felix Wankel researched internal-combustion engines in the 1930s. During World War II (1939-1945) he worked in aeronautical research, but after the war he continued his research on engines. He produced a successful prototype of the engine during the mid-1950s. The first automobile fitted with a Wankel engine was the Spyder produced during the mid-1960s by the company NSU (Neckarsulmer Strickmaschinen Union).

In addition to automobiles, the Wankel engine has been used successfully in trucks, boats, electric generators, golf carts, lawn mowers, snowmobiles, and motorcycles. The aircraft industry has also shown interest in the engine, since it is small and more easily serviceable than piston engines. Use of the Wankel engine, however, has been limited by the engine’s comparatively high fuel consumption and exhaust emissions.