In 1957, Wankel of Germany manufactured the world's first rotary engine and obtained the patent right. But now only Mazda in Japan is studying it. The following is a detailed introduction to the rotary engine: 1. The rotor of a rotary engine works once every revolution. Compared with the general four-stroke engine, which only does work once every two revolutions, it has the advantage of high horsepower-volume ratio (smaller engine volume can output more power). 2. Because of the axial running characteristics of the rotary engine, it can achieve higher running speed without accurate crankshaft balance. The whole engine has only two rotating parts. Compared with the general four-stroke engine with more than 20 moving parts such as intake and exhaust valves, the structure is greatly simplified and the possibility of failure is greatly reduced. In addition to the above advantages, the advantages of rotary engine include smaller size, light weight, low center of gravity and so on.