Patent ID: 7739016

Claim:
Method to estimate a control parameter for a powertrain system, the powertrain system comprising a plurality of torque-generative devices operably connected to a transmission device having a torque output to a driveline, comprising: establishing a plurality of equations operable to estimate the control parameter and a plurality of operating parameters based upon a plurality of torque inputs, said plurality of operating parameters comprising operating speeds of the powertrain system and driveline, said plurality of torque inputs comprising at least one of torque outputs of each of the torque-generative devices, transmission clutch torques, brake torque, road load torque, and accessory torque; determining the operating parameters that comprise operating speeds of the powertrain system and driveline; and adjusting coefficients of the plurality of equations based upon the operating speeds of the powertrain system; wherein said transmission clutch torques are estimated by determining a magnitude of torque applied to each clutch, based upon commanded hydraulic pressure to each clutch, and determining a magnitude of clutch slip for each clutch, based upon rotational speeds of the electrical machines and the operating speeds of the powertrain system comprising a transmission output speed.