Abstract: An external combustion engine comprises an actuating cylinder in which a piston with rod is mounted for reciprocation, said piston serving as the actuating member, a valve distributor serving as the switching member, as well as a crank gear serving as the converter of the piston reciprocation to the drive shaft revolution. The piston divides the cylinder cavity into two, namely, a rod cavity and a rodless cavity. Each one of the cavities communicates with a source of working fluid via valve distributor. The piston rod is operatively connected with the drive shaft via crank gear. The engine further comprises an electric oscillator whose frequency is variable in accordance with the preset r.p.m. of the drive shaft, connected electrically with the converter in the form of a linear dynamic link, and a transducer indicating the current value of the piston position relative to its neutral position. The linear dynamic link is coupled mechanically with the distributor slide valve.

Abstract: A method of controlling the revolution of the drive shaft of an external combustion engine comprises shaping a control signal for a switching member and converting said signal to mechanical movement of an actuating member. The control signal is shaped in the form of symmetric, periodic sustained vibrations of variable sign, the time intervals of positive and negative values of said vibrations being of equal duration, and the frequency of said vibrations is set equal to a preset number of drive shaft revolutions. The variation of said movement corresponds in time to variation of the control signal, an instantaneous value of the control signal is varied in proportion to the variation of load on the drive shaft, and the actuating member movement is converted to revolution of the engine drive shaft.