Abstract: A method for stabilizing selection between a plurality of operating range states of an electro-mechanical multi-mode transmission configured to transfer torque among an engine, at least one electric machine, and a driveline includes requesting operation of the transmission in a preferred operating range state while a shift from a first operating range state to a second operating range state is in progress prior to achieving the second operating range state. Powertrain information is monitored and compared to a driver perception threshold only if a change of mind condition is detected. The shift to the second operating range state is avoided and a shift to the preferred operating range state is commanded if the powertrain information does not violate the driver perception threshold.

Abstract: A method for stabilizing selection between a plurality of operating range states of an electro-mechanical transmission configured to transfer torque among an engine, at least one electric machine, and a driveline includes requesting execution of a shift from a first operating range state to a second operating range state. Costs associated with operating the transmission in each of the plurality of operating range states including the first and second operating range states are monitored and an energy differential between the first and second operating range states is determined based on the monitored costs. The shift from the first operating range state to the second operating range state is executed only if the energy differential achieves an integration threshold.

Abstract: A method for determining a preferred engine speed and a preferred engine torque of a selected operating range state of an electro-mechanical multi-mode transmission configured to transfer torque among an engine, at least one electric machine and a drive includes selecting between of a first search window and a second search window. Each of the first and second search windows includes a two-dimensional search window definable by a first axis having minimum and maximum engine speed values and a second axis having minimum and maximum engine torque values. A plurality of candidate operating points within the selected one of the first and second search windows is iteratively generated. One of the plurality of candidate operating points within the selected one of the first and second search windows is iteratively determined as an optimum operating point.

Abstract: A method for operating a powertrain system including a multi-mode transmission configured to transfer torque among an engine, torque machines, and a driveline, includes executing a first search to determine a first engine operating point within an all-cylinder state and a corresponding operating cost for operating the powertrain system in response to an output torque request. A second search is executed to determine a second engine operating point within a cylinder deactivation state and a corresponding operating cost for operating the powertrain system in response to the output torque request. One of the first and second engine operating points is selected as a preferred engine operating point based upon the operating costs and the engine is controlled at the preferred engine operating point in the corresponding one of the all-cylinder state and the cylinder deactivation state.

Abstract: A method for operating a powertrain system to transfer torque among an engine, torque machines, and a driveline includes 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. The search includes employing a 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 for each of a plurality of candidate engine speeds within an input speed range and a plurality of candidate torque normalization ratios. A preferred engine speed is determined, and includes the candidate engine speed corresponding to the one of the candidate engine torques associated with a minimum of the candidate power costs. Engine operation is controlled responsive to the preferred engine speed.

Abstract: A method for operating a powertrain system includes selecting a plurality of candidate transmission ranges associated with a present powertrain operating point and deselecting candidate transmission ranges not associated with the present powertrain operating point. A high resolution engine speed/torque search is executed for each of the selected candidate transmission ranges. A low resolution engine speed/torque search is executed for each of the deselected candidate transmission ranges. Each search is executed to determine a respective minimum power cost for operating the powertrain system in one of the candidate transmission ranges in response to an output torque request and output speed. A preferred transmission range is determined from the candidate transmission ranges. A preferred engine operating point is determined corresponding to the minimum power cost for the preferred transmission range.

Abstract: A method for operating a vehicle including a hybrid powertrain system includes enabling a commanded electric vehicle (EV) launch when a high-voltage battery state-of-charge (SOC) is greater than an SOC threshold, a transmission output speed is less than a low speed threshold, a transmission output torque is less than a speed-based torque threshold, and an operator torque request is achievable in the EV traction mode. An EV traction mode is employed to execute the commanded EV launch in response to the operator torque request including a launch maneuver.