Patent ID: 8165777

Claim:
Method for controlling a powertrain system including an engine coupled to an input member of a hybrid transmission, the hybrid transmission operative to transmit torque between the input member and a torque generating machine and an output member, the hybrid transmission operative in one of a plurality of operating range states to transfer power between the input member and the torque generating machine and the output member, the method comprising: monitoring an operator torque request; determining an output torque command and an output speed of the output member; selecting candidate operating range states; iteratively selecting candidate input speeds to the input member for each of the candidate operating range states; determining mechanical power loss in the hybrid transmission in each of the candidate operating range states for each of the candidate input speeds and the output speed; selecting a preferred input speed comprising the candidate input speed that achieves a minimum mechanical power loss in the hybrid transmission at the candidate operating range state for each of the selected operating range states at the output speed; and selecting a preferred operating range state comprising the candidate operating range state having the minimum preferred input speed at the output speed.