The control system encompasses a IC engine (1), an electric motor and electrogenerator (motor-generator set) (2) and a gear (transmission) system (4). A planetary gear (30) is connected to the drive mechanism (1) via a drive coupling and is also connected to the motor-generator set (2) and the gears (4). The system also includes a motor drive device to control the motor-generator (2) in a predetermined direction before pulling the coupling back in. When the coupling is retracted the motor drive device controls the generator to lock the drive mechanism (1) and the motor-generator (2) via the planetary gear (30) to output a reaction force of a torque of the drive mechanism to the motor-generator. Preferably the motor drive device varies the drive force of the generator, such that the rotational speed of a rotary component of the planetary gear can be synchronised with the drive mechanism rotational speed.
