Patent ID: 8219303

Claim:
A method for operating a hybrid powertrain system including an internal combustion engine operatively connected to first and second torque machines to transmit torque to an output member, the method comprising: monitoring an operator torque request; determining an output torque command based upon the operator torque request; commanding a transition between an engine-off state and an engine-on state; monitoring an engine crank angle; operating the first torque machine to spin the engine unfueled; estimating cylinder pressure based upon the engine crank angle during the spinning of the engine; predicting a cylinder pulse torque based upon the cylinder pressure; determining a cancellation torque for the first torque machine based upon the predicted cylinder pulse torque; and controlling the motor torque output of the first torque machine in response to both the cancellation torque and the output torque command and controlling the motor torque output of the second torque machine only in response to the output torque command.