DIESEL ENGINE STEADY STATE AND TRANSIENT HYBRID OPTIMIZATION

A method for selecting an engine operating point in a multi-mode powertrain system includes monitoring a desired axle torque based on an operator torque request and vehicle speed. For each available combustion mode of the diesel engine, engine torque and speed ranges are received and a plurality of fuel losses and a plurality of emissions losses are retrieved, each fuel and emissions loss corresponding to respective ones of a plurality of engine operating points within the engine torque and speed ranges. The respective fuel and emissions losses are compared at each of a plurality of potential engine operating points within the engine torque and speed ranges of the available combustion modes. A desired engine operating point within one of the available combustion modes is selected that corresponds to one of the potential engine operating points having a lowest power loss based on the compared respective fuel and emissions losses.