Abstract: In a power unit for a vehicle, an internal combustion engine, equipped with electromagnetic valves on the respective cylinders and a generator connected to the output shaft of the engine, is provided. The electromagnetic valves are controlled by an electromagnetic valve actuating device. The generator converts at least a part of the engine output into electric power. The generated electric power is stored in a battery. The electric power stored in the battery is supplied to a motor in order to drive the vehicle. A control unit controls the output of motor in accordance with the requirement of the driver of the vehicle. Since the engine is not directly controlled by the driver, the engine can be operated at a predetermined speed range regardless of the requirements of the driver. This speed range is selected so that the maximum reliability and durability of the electromagnetic valves can be obtained.