Method and apparatus to determine a preferred output torque in mode and fixed gear operation with clutch torque constraints for a hybrid powertrain system

Method for controlling a hybrid transmission operative to transfer torque between an input member and torque machines and an output member in one of a plurality of fixed gear and continuously variable operating range states through selective application of torque transfer clutches, the torque machines operative to transfer power from an energy storage device, the method comprising:

• applying torque transfer clutches and operating the hybrid transmission in one of the operating range states;
• determining clutch reactive torque ranges of the applied clutches, motor torque ranges of the torque machines, and power transferred from the energy storage device;
• determining constraints on the output torque transferred to the output member based upon the clutch reactive torque ranges of the applied clutches;
• determining constraints on the output torque transferred to the output member based upon the motor torque ranges of the torque machines;
• determining constraints on the output torque transferred to the output member based upon the power transferred from the energy storage device;
• determining an allowable output torque range that is achievable within the constraints on the output torque transferred to the output member based upon the clutch reactive torque ranges of the applied clutches, the motor torque ranges of the torque machines, and the power transferred from the energy storage device;
• and
• controlling output torque from the transmission based upon the allowable output torque range.

Method for controlling a hybrid transmission operative to transfer torque between an input member and first and second torque machines and an output member in one of a plurality of fixed gear and continuously variable operating range states through selective application of torque transfer clutches, the torque machines operative to transfer power from an energy storage device, the method comprising:

• determining an operator torque request;
• determining clutch reactive torque ranges of applied clutches, motor torque ranges of the torque machines, and power transferred from the energy storage device;
• determining constraints on the output torque transferred to the output member based upon the clutch reactive torque ranges of the applied clutches;
• determining constraints on the output torque transferred to the output member based upon the motor torque ranges of the torque machines;
• determining constraints on the output torque transferred to the output member based upon the power transferred from the energy storage device;
• inducing a constraint on the clutch reactive torque range of one of the applied clutches;
• determining constraints on the output torque transferred to the output member based upon the induced constraint on the clutch reactive torque range of one of the applied clutches;
• determining an allowable output torque that is achievable within the constraints on the output torque transferred to the output member based upon the clutch reactive torque ranges of the applied clutches, the motor torque ranges of the torque machines, the power transferred from the energy storage device, and the induced constraint on the clutch reactive torque range of one of the applied clutches;
• and
• controlling the motor torques of the torque machines based upon the allowable output torque.