Abstract: A vehicle having an internal combustion engine and flywheel includes a first clutch arranged between the flywheel and the vehicle drive shaft and a second clutch arranged between the flywheel and engine for selectively disconnecting the engine from the vehicle drive. A motor-generator is connected to the flywheel by a planetary gear train which includes a planetary gear carrier rigidly connected with the output drive shaft. during a first driving stage, the clutch between the flywheel and vehicle drive shaft is disconnected, such that the flywheel is coupled to the drive shaft through the planetary gear train. In a second driving stage, the clutch between the flywheel and vehicle output shaft is engaged to effect a direct connection between the flywheel and output shaft. In both driving stages, the vehicle can be driven by the engine, or by the motor-generator, or by the engine and motor-generator combined.