Abstract:
A powertrain system includes an internal combustion engine rotatably coupled to a non-combustion torque machine and a torque converter which is rotatably coupled to an input member of a transmission. A method for operating the powertrain system includes operating the torque converter in a controlled slip operating state and controlling a torque converter clutch capacity in response to a driver requested braking torque. Target torque outputs from the engine and from the torque machine are determined in response to the driver requested braking torque subjected to a time delay. A torque modifier for the torque machine is determined in response to a torque converter clutch slip error. Torque output from the engine is controlled in response to the target torque output from the engine, and torque output from the torque machine is controlled in response to the target torque output and the torque modifier from the torque machine.