Abstract: A multi-mode powertrain system is described, and includes an internal combustion engine and electric machines operative to transfer mechanical power through a gear train to an output member coupled to a driveline, wherein the electric machines electrically connect to a battery. The method includes determining an audible noise-based maximum engine speed, wherein the internal combustion engine generates an audible noise that is less than a threshold noise level when operating at a speed that is less than the audible noise-based maximum engine speed. The electric machines and the internal combustion engine are controlled responsive to an operator torque request including controlling the engine speed to be less than the audible noise-based maximum engine speed when battery power is greater than a minimum threshold.

Abstract: A method for controlling operation of a multi-mode powertrain system includes periodically determining a power cost difference between a first power cost and a second power cost. This includes determining the first power cost associated with operating the powertrain system with the engine operating in a presently commanded engine state in response to an operator torque request and determining the second power cost associated with an expected powertrain operation with the engine operating in a non-commanded engine state in response to the operator torque request. The first power cost is compared with the second power cost, and successive iterations of the periodically determined power cost difference between the first power cost and the second power cost are integrated to determine an integrated power cost difference. A transition to the non-commanded engine state is commanded when the integrated power cost difference is greater than a threshold.

Abstract: A multi-mode powertrain system is described, and includes an internal combustion engine and electric machines operative to transfer mechanical power through a gear train to an output member coupled to a driveline, wherein the electric machines electrically connect to a battery. The method includes determining an audible noise-based maximum engine speed, wherein the internal combustion engine generates an audible noise that is less than a threshold noise level when operating at a speed that is less than the audible noise-based maximum engine speed. The electric machines and the internal combustion engine are controlled responsive to an operator torque request including controlling the engine speed to be less than the audible noise-based maximum engine speed when battery power is greater than a minimum threshold.

Abstract: A method for controlling operation of a multi-mode powertrain system includes periodically determining a power cost difference between a first power cost and a second power cost. This includes determining the first power cost associated with operating the powertrain system with the engine operating in a presently commanded engine state in response to an operator torque request and determining the second power cost associated with an expected powertrain operation with the engine operating in a non-commanded engine state in response to the operator torque request. The first power cost is compared with the second power cost, and successive iterations of the periodically determined power cost difference between the first power cost and the second power cost are integrated to determine an integrated power cost difference. A transition to the non-commanded engine state is commanded when the integrated power cost difference is greater than a threshold.

Abstract: A multi-mode powertrain system employing a power-split configuration to transfer torque to a driveline includes an internal combustion engine fluidly coupled to an exhaust aftertreatment system having a catalytic device. A method for controlling the multi-mode powertrain system includes identifying permitted transition paths between a plurality of engine states. The plurality of engine states includes a default state, a pre-light-off state, a light-off state, and a post-light-off state. A preferred one of the plurality of engine states is selected in response to an output torque request and an operating temperature of the catalytic device. Engine operation is transitioned to the preferred one of the plurality of engine states via the permitted transition paths, and the engine is operated in the preferred one of the plurality of engine states.

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 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 multi-mode powertrain system employing a power-split configuration to transfer torque to a driveline includes an internal combustion engine fluidly coupled to an exhaust aftertreatment system having a catalytic device. A method for controlling the multi-mode powertrain system includes identifying permitted transition paths between a plurality of engine states. The plurality of engine states includes a default state, a pre-light-off state, a light-off state, and a post-light-off state. A preferred one of the plurality of engine states is selected in response to an output torque request and an operating temperature of the catalytic device. Engine operation is transitioned to the preferred one of the plurality of engine states via the permitted transition paths, and the engine is operated in the preferred one of the plurality of engine states.