RKM engine

The Schapiromotor is a rotary engine of the mathematician Boris Schapiro. Schapiro invented the motor end of the 1960s. As the Wankel engine is based on the Schapiromotor a circular triangular flask with curved sides. However, the piston revolves not only one but two waves, resulting in a better contact between the piston and the combustion chamber results in edges, which can be dispensed with strong seals are subject to wear. In contrast to the Wankel engine, it needs valves to control the gas exchange.

The idea for the second wave, which serves as a discontinuous axis of rotation of a gear, Schapiro developed in 1995.

So far, no executable engine demonstrated (as of 2008 ).