The operating principle of the motor is based on an internal gearbox consisting of a fixed toothed ring with internal teeth and a gearwheel meshing with it, through which the output torque and speed are transmitted. The distributor valve is driven synchronously with the gear set so that the filling and emptying of the individual chambers of the engine takes place precisely - without losses. The drum valve is part of the output shaft. The cardan shaft transmits the mechanical energy from the gear set to the output shaft.