Method and apparatus for selecting an engine operating state for a multi-mode powertrain system

A method for controlling operation of a powertrain system including a multi-mode transmission configured to transfer torque among an engine, torque machines, and a driveline, the method comprising, for each of a plurality of loop cycles:

• determining a bias engine speed based upon an engine speed for an immediately previous loop cycle and an expected change in the engine speed for an immediately previous loop cycle and determining an engine speed driveability cost;
• and
• executing a search, comprising:
• for each of a plurality of candidate engine operating points including candidate engine speeds:
• determining a respective candidate power cost for operating the powertrain system in response to an output torque request, and
• determining a respective candidate driveability cost for the candidate engine speed based upon the bias engine speed;
• selecting one of the candidate engine operating points that achieves a minimum of a combination of the respective candidate driveability cost and the candidate power cost as a preferred engine operating point;
• and
• controlling operation of the powertrain system based upon the preferred engine operating point.

A method for controlling operation of a powertrain system including a multi-mode transmission configured to transfer torque among an engine, torque machines, and a driveline, the method comprising, for each of a plurality of loop cycles:

• determining a bias engine speed based upon an engine speed for an immediately previous loop cycle and an expected change in the engine speed for an immediately previous loop cycle and determining an engine speed driveability cost;
• and
• executing a search, comprising:
• for each of a plurality of candidate engine operating points including candidate engine speeds:
• determining a respective candidate power cost for operating the powertrain system in a transmission range in response to an output torque request, and
• determining a respective candidate driveability cost for the candidate engine speed based upon the bias engine speed;
• selecting one of the candidate engine operating point that achieves a minimum of a combination of the respective candidate driveability cost and the respective candidate power cost as a preferred engine operating point for operating the powertrain system in the transmission range in response to the output torque request;
• and
• controlling operation of the powertrain system in the transmission range in response to the output torque request including controlling the engine at the preferred engine operating point.