Method and apparatus for clutch torque control in mode and fixed gear for a hybrid powertrain system

Method for controlling a hydraulic line pressure of a hydraulic control system in an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member via selective application of a plurality of hydraulically-applied torque transfer clutches, said method comprising:

• monitoring a current output torque of said transmission;
• monitoring a requested output torque command;
• adjusting a minimum clutch torque capacity as a feed-forward control comprising:
• determining a line pressure compensation factor based upon a greater of one and a ratio of said requested output torque to said current output torque;
• and
• adjusting said minimum clutch torque capacity based upon said line pressure compensation factor;
• and
• controlling said hydraulic line pressure by modulating operation of said hydraulic control system based upon said minimum clutch torque capacity;
• wherein said current output torque is generated by providing mechanical power from said electric machine and selectively providing mechanical power from said engine.