Parallel hybrid vehicle employing parallel hybrid system, using both internal combustion engine and electric motor generator for propulsion

A parallel hybrid vehicle employing a parallel hybrid system, using both an internal combustion engine and an electric motor generator for propulsion, said parallel hybrid vehicle comprising:

• a torque composition means including a differential system for combining a torque output produced by the engine and a torque output produced by the motor generator to generate a combined torque, said torque composition means connected via a transmission in a powertrain to drive wheels for outputting the combined torque via the transmission to the drive wheels;
• a direct-coupling clutch which directly couples the engine with the motor generator;
• an engine-speed sensor means for detecting engine speed of the engine;
• a throttle opening sensor means for detecting a throttle opening of a throttle valve;
• a torque control means connected electrically to the motor generator and the direct-coupling clutch for controlling the torque output produced by the motor generator and engagement and disengagement of the direct-coupling clutch, said torque control means allowing the direct-coupling clutch to operate in a disengaged state and allowing the engine speed to be maintained at a predetermined value and allowing the direct-coupling clutch to engage at a timing when the engine speed synchronizes a rotational speed of the motor generator during starting of the vehicle;
• said torque control means comprising:
• (a) a desired motor/generator torque setting means for setting a desired motor/generator torque on the basis of both the engine speed and the throttle opening from a predetermined characteristic map to generate a signal indicative of the desired motor/generator torque, and
• (b) a response-characteristic compensating means for attenuating high-input-frequency components and for passing low-input-frequency components, out of the signal indicative of the desired motor/generator torque set through the desired motor/generator torque setting means, to generate a compensated signal;
• and
• said torque control means controlling the torque output of the motor generator on the basis of a signal value of the compensated signal generated by the response-characteristic compensating means.

An electronic control method for a parallel hybrid vehicle employing a parallel hybrid system, using both an internal combustion engine and an electric motor generator for propulsion and including a direct-coupling clutch directly coupling the engine with the motor generator, and an engine-braking clutch incorporated in a transmission in a powertrain, the electronic control method comprising:

• detecting a throttle opening of a throttle valve;
• calculating an average throttle opening as a time mean of the throttle opening;
• detecting engine speed of the engine;
• calculating an average engine speed as a time mean of the engine speed;
• retrieving a desired motor/generator torque of the motor generator on the basis of the average throttle opening and the average engine speed from a predetermined characteristic map to produce a signal indicative of the desired motor/generator torque;
• calculating an average desired motor/generator torque as a time mean of the desired motor/generator torque;
• detecting a reduction ratio of the transmission in the powertrain;
• detecting input information regarding which state the direct-coupling clutch is in;
• detecting input information regarding which state the engine-braking clutch is in;
• selecting a response-characteristic-compensator frequency characteristic responsively to the reduction ratio of the transmission, the input information regarding which state the direct-coupling clutch is in, and the input information regarding which state the engine-braking clutch is in;
• making a response-characteristic compensating process of the selected response-characteristic-compensator frequency characteristic to the signal indicative of the average desired motor/generator torque to generate a compensated motor/generator torque command;
• and
• controlling the motor generator in response to the compensated motor/generator torque command.