Patent Document ID: 8761988
Application ID: 13568061

Base Claim:
1. A method for operating a powertrain system including a multi-mode transmission configured to transfer torque among an engine, torque machines, and a driveline, the method comprising: executing a search to determine a preferred engine operating point for operating the powertrain system in a transmission range in response to an output torque request, said search comprising: for each of a plurality of candidate engine speeds within an input speed range and each of a plurality of candidate torque normalization ratios wherein the candidate torque normalization ratios for the candidate engine speed include a normalized engine torque at 0.0 corresponding to a minimum permissible engine torque for the candidate engine speed and a normalized engine torque at 1.0 corresponding to a maximum permissible engine torque for the candidate engine speed: employing the candidate torque normalization ratio to determine a candidate engine torque from a normalized torque search space, and determining a candidate power cost associated with operating the powertrain system at the candidate engine torque; determining a preferred engine speed comprising the candidate engine speed corresponding to the one of the candidate engine torques associated with a minimum of the candidate power costs; and controlling engine operation responsive to the preferred engine speed.

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Claim 6:
6. The method of claim 1 , wherein determining the candidate power cost associated with operating the powertrain system at the candidate engine torque comprises: determining a preferred powertrain operating point in response to the output torque request when the engine is operating at the candidate engine torque; and determining the candidate power cost at the preferred powertrain operating point.