Abstract
Possibilities of combustion engine - electric machine assembly run irregularity improvement have been presented in the following paper. Such system is the basic one in numerous hybrid car available on the market but the concept of using an electrical machine for reduction of rotational speed changeability amplitude in reciprocating machines could be utilized in any drive unit, especially in ship propulsion. This idea consists in generation of braking torque by the electric machine whenever the coupling shaft increases its rotational speed and vice versa, driving the system when the momentary speed is lower than the average speed within a complete shaft rotation.