Felix Wankel, a German engineer who invented the rotary engine, is born on Aug. 13, 1902, in Lahr, Germany. Wankel became fascinated with internal combustion engines at an early age and began developing a rotary engine concept as early as 1924.
With a gift for mathematics and technical drawing, he dreamed of developing a new type of engine that would combine the best features of piston engines and turbines.
In standard internal-combustion engines, moving pistons started and managed the combustion process. In Wankel's rotary engine, an orbiting rotor in the shape of a curved equilateral triangle handled combustion. It is designed to generate more power in less space than conventional engines.
Wankel received his first patent for a pistonless internal combustion engine in 1929.
It proved to be one of many engine developments ahead of its time.
NSU Motorenwerke AG, a German automaker eventually purchased by Volkswagen Group and merged into what became Audi, began work on a rotary engine in 1951. Wankel had signed a consulting agreement with NSU and designed the company's first working prototype; the DKM 54.
The DKM was first operated in February 1957.
The first design had an inner rotating housing and rotor moving around a central shaft. Rotary engines were smaller and lighter than their piston counterparts while still capable of generating enough horsepower and high rpms with turbinelike smoothness.
But rotary engines also had major shortcomings. The original motors had to be disassembled to change the spark plugs. Early models had problems with combustion chamber sealing and poor emissions performance. And their noncylindrical parts were difficult and expensive to mass produce.
A second prototype rotary engine, the KKM 57, was also created by NSU. The KKM was a radical departure from Wankel's original concept and was built without his knowledge. The second design was adopted by NSU for automotive applications due to its superior low-speed operation and serviceability.
In 1964, NSU introduced the world's first rotary powered car, the Spider. Mazda introduced its own rotary powered car, the Cosmo, three years later. Mazda had formed a licensing pact with NSU in 1961 to conduct its own rotary engine development. Mazda President Tsuneji Matsuda wanted a signature technology to distinguish the small but growing Japanese automaker. After hearing of NSU's work on the rotary engine concept, Matsuda was convinced the design and mechanical elegance was just what Mazda needed to stand out.
The first Mazda with a Wankel engine was introduced in the United States in 1971. Over the first ten years, Mazda sold 200,000 rotary-engine cars in the United States, with prices up to $12,000.
Daimler-Benz, Alfa Romeo, Rolls Royce, Porsche, General Motors, Suzuki and Toyota also licensed the rotary engine at one point starting in the 1960s.
GM heavily promoted rotary engine technology in 1973 but abruptly canceled a testing program in 1974.
Wankel died in 1988 at age 86.