Hybrid drive system for vehicle with clutch control

A hybrid drive system for a vehicle, comprising:

• at least one driven wheel;
• a first electric motor having a first rotor in driving relationship to said driven wheel via a transmission;
• a fuel powered heat engine having an engine drive shaft;
• a second electric motor having a second rotor in driving connection to said engine drive shaft,
• a clutch between said engine drive shaft and said first rotor;
• and
• a controller for generating a command to engage said clutch in response to the vehicle operator's torque request demand and the vehicle speed, comparing the vehicle operator's torque request demand with the maximum input torque by said second electric motor and the maximum output torque by said first electric motor, and controlling operation of the procedure of engagement of said clutch beginning with said command in response to result from said comparison.

A hybrid drive system for a vehicle, comprising:

• at least one driven wheel;
• a first electric motor having a first rotor in driving relationship to said driven wheel;
• a fuel powered heat engine having an engine drive shaft;
• a second electric motor having a second rotor in driving connection to said engine drive shaft,
• a clutch to engage and disengage said heat engine to and from said first rotor;
• and
• means for translating the vehicle operator's torque request demand into operation of said first electric motor, said second electric motor and said clutch in response to a command to engage said clutch.

A method of operating a vehicle hybrid drive system including an electric motor in driving relationship to a driven wheel, a heat engine, and a clutch to engage and disengage the heat engine to and from the electric motor, comprising:

• sensing vehicle operator's desire relative to movement of the vehicle;
• translating the sensed vehicle operator's desire into vehicle operator's torque request demand;
• generating a command to engage the clutch;
• and
• translating the vehicle's operator torque request demand into operation of the engine, operation of the electric motor and operation of the clutch during transient period beginning with said command to engage the clutch.