Method and apparatus for fault mitigation in a torque machine of a powertrain system

Method for operating a powertrain system including an internal combustion engine rotatably coupled to a torque machine via a pulley mechanism, said torque machine and internal combustion engine configured to transfer torque to a driveline and including a first sensor configured to monitor rotation of the engine and a second sensor configured to monitor rotation of the torque machine, the first sensor directly signally connected to a first controller configured to control operation of the engine and the second sensor the first sensor signally connected to a second controller configured to control operation of the torque machine, the method comprising:

• upon detecting a fault associated with the second sensor, employing a signal output from the first sensor to monitor rotation of the torque machine to control operation thereof, said signal output from the first sensor adjusted for a pulley ratio of the pulley mechanism, including;
• derating the operation of the torque machine to a reduced maximum torque capability by reducing a maximum electric power capability of the torque machine upon detecting the fault associated with the second sensor;
• and
• operating the torque machine with the reduced maximum torque capability to generate electric power to support a vehicle electric load including limiting regenerating torque output from the torque machine to effect battery charging based upon the reduced maximum electric power capability.