Method and apparatus to control operation of an electro-mechanical transmission

Article of manufacture, comprising a storage medium having a computer program encoded therein for effecting a method to control a powertrain system including an internal combustion engine, electrical machines and an electro-mechanical transmission device configured to transmit torque to an output shaft, the transmission device comprising a plurality of torque-transfer clutches each actuable by selective control of a hydraulic circuit comprising a plurality of flow control devices and pressure monitoring devices, the computer program comprising:

• code to monitor pressures in the hydraulic circuit;
• code to identify a fault in the torque transmission device when any one of the monitored pressures in the hydraulic circuit does not correspond to an expected pressure thereat;
• code to restrict operation of the transmission device and controlling operation of the internal combustion engine and the electrical machines to maintain a torque output to the output shaft;
• and,
• code to verify presence of the fault during the restricted operation.

Apparatus, comprising:

• an internal combustion engine and first and second electrical machines and an electro-mechanical transmission operative to transmit torque therebetween and transmit torque to an output shaft;
• the transmission comprising an electro-hydraulic control circuit comprising a plurality of pressure monitoring devices and a plurality of selectively controllable flow control devices, and, a plurality of torque-transfer clutches;
• the transmission operative in one of a plurality of operating modes comprising fixed gear ratio modes and two continuously variable modes;
• and
• a control system configured to:
• control the flow control devices of the electro-hydraulic control circuit;
• and,
• execute a computer program to selectively control the flow control devices of the electro-hydraulic control circuit during execution of a shift, comprising:
• code to monitor hydraulic pressures in the hydraulic circuit;
• code to identify a fault and restrict operation of the transmission when any one of the monitored hydraulic pressures in the hydraulic circuit does not correspond to an expected pressure thereat;
• code to control operation of the internal combustion engine and the first and second electrical machines to maintain a torque output to the output shaft during the restricted operation of the transmission;
• and,
• code to verify presence of the fault in the hydraulic circuit during the restricted operation.