Mazda Rotary Engine Pioneer Yamamoto Dies

Kenichi Yamamoto, the engineer who led Mazda Motor Corp.’s rotary engine program, died on Dec. 20 at the age of 95.

Yamamoto joined Mazda, then known as Toyo Kogyo, in 1946. In 1961 he was named to head the team that successfully commercialized the Wankel rotary engine in the late 1960s.

Yamamoto successfully led Mazda from obscurity to a global presence. But he was above all recognized as the father of the Wankel rotary engine, a fact he attributed to Mazda’s decades-long commitment to advancing the technology.

The engine, with its distinctive triangular rotor (above), was patented by German inventor Felix Wankel in the late 1920s. The technology was made commercially viable in the early 1950s by Germany’s NSU Motorenwerke AG. NSU (later acquired by Audi AG) also began licensing the technology in 1960 to such carmakers as American Motors, Ford, General Motors, Mercedes-Benz, Nissan and Toyota.

NSU introduced the first Wankel-powered model, a sports car, in Europe in 1964, followed by the RO 80 sedan in 1967. But neither car sold well, largely because of engine rotor and oil sealing failures.

Since then the company has continued development of a small Wankel-powered electrical generator designed to extend the range of electric cars. Mazda said last month it intends to introduce the device in 2019.