Method and apparatus to monitor output of an electro-mechanical transmission

Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to transmit mechanical power flow to an output through selective actuation of a plurality of torque-transfer clutches, the method comprising:

• monitoring an operator torque request;
• determining maximum and minimum allowable transmission output torques based upon the operator torque request, wherein determining the maximum allowable transmission output torque based upon the operator torque request comprises combining the operator torque request, an electrical regeneration torque, and a positive torque offset;
• determining a commanded transmission output torque;
• and comparing the commanded transmission output torque and each of the maximum and
• minimum allowable transmission output torques;
• wherein determining the minimum allowable transmission output torque based upon the operator torque request comprises establishing a minimum threshold torque when the operator torque request is positive.

Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to transmit mechanical power flow to an output through selective actuation of a plurality of torque-transfer clutches, the method comprising:

• monitoring an operator torque request;
• determining maximum and minimum allowable transmission output torques based upon the operator torque request;
• determining a commanded transmission output torque;
• and
• comparing the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques;
• wherein determining the minimum allowable transmission output torque based upon the operator torque request comprises subtracting a negative torque offset from the operator torque request when the operator torque request is negative.

Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to transmit mechanical power flow to an output through selective actuation of a plurality of torque-transfer clutches, the method comprising:

• monitoring an operator torque request;
• determining maximum and minimum allowable transmission output torques based upon the operator torque request;
• determining a commanded transmission output torque;
• comparing the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques;
• and
• intervening when the commanded transmission output torque falls outside of one of the maximum and minimum allowable transmission output torques X times out of Y preceding executions of the code.

Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to transmit mechanical power flow to an output through selective actuation of a plurality of torque-transfer clutches, the method comprising:

• monitoring an operator torque request;
• determining maximum and minimum allowable transmission output torques based upon the operator torque request;
• determining a commanded transmission output torque;
• and
• comparing the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques;
• wherein monitoring the operator torque request comprises monitoring a magnitude and a rotational direction of the operator torque request.

Article of manufacture, comprising a storage medium having a machine-executable program encoded therein to monitor operation of an electro-mechanical transmission adapted to transmit mechanical power flow to an output shaft, the program comprising:

• code to monitor an operator torque request and an operator command for rotational direction;
• code to determine maximum and minimum allowable transmission output torques based upon the operator torque request;
• code to determine a commanded transmission output torque and a rotational direction of the output;
• code to compare the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques;
• and
• code to compare the rotational direction of the output to the operator command for rotational direction;
• wherein the code to determine the maximum allowable transmission output torque based upon the operator torque request comprises arithmetically adding the operator torque request, any commanded electrical regeneration torque, and a positive torque offset.

Article of manufacture, comprising a storage medium having a machine-executable program encoded therein to monitor operation of an electro-mechanical transmission adapted to transmit mechanical power flow to an output shaft, the program comprising:

• code to monitor an operator torque request and an operator command for rotational direction;
• code to determine maximum and minimum allowable transmission output torques based upon the operator torque request;
• code to determine a commanded transmission output torque and a rotational direction of the output;
• code to compare the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques;
• and
• code to compare the rotational direction of the output to the operator command for rotational direction;
• wherein the code to determine the minimum allowable transmission output torque based upon the operator torque request comprises establishing a minimum threshold torque when the operator torque request is positive.

Article of manufacture, comprising a storage medium having a machine-executable computer program encoded therein operative to control a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and a plurality of electric machines each adapted for mechanical power flow to an output through selective actuation of a plurality of torque-transfer clutches;

• the program comprising:
• code to monitor an operator torque request;
• code to determine maximum and minimum allowable transmission output torques based upon the operator torque request;
• code to determine a regeneration torque;
• code to determine electric machine torque commands;
• code to determine a commanded transmission output torque based upon the electric machine torque commands;
• code to compare the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques;
• and
• code to intervene when the commanded transmission output torque falls outside of one of the maximum and minimum allowable transmission output torques X times out of Y preceding executions of the code.