Control system for hybrid vehicles

There is provided a control system for a hybrid vehicle including an internal combustion engine (1), a drive shaft (2) driven by the engine, a motor (3) having an assisting function of driving the drive shaft by operating on electrical energy and a regenerating function of converting kinetic energy of the drive shaft to electrical energy, and an electrical storage device (14) for supplying electrical energy to the motor (3) and for storing electrical energy output from the motor. An amount of remaining charge in the electrical storage device is detected. A demanded output of the engine is calculated based on operating conditions of the engine. Running resistance of the hybrid vehicle is calculated based on running conditions of the hybrid vehicle. An extra output of the engine is calculated based on the demanded output of the engine and the running resistance of the hybrid vehicle. A desired output of the motor (3) is calculated based on the extra output of the engine (1). An operating mode of the motor is determined based on the amount of remaining charge in the electrical storage device and the desired output of the motor. An output from the motor is controlled based on the operating mode of the motor and the desired output of the motor.