Abstract: A powertrain system is described, and includes an internal combustion engine and an electric machine configured to generate propulsion torque responsive to a driver torque request. A method for operating the powertrain system includes determining, in response to a request to execute an engine autostart operation, whether a driveline torque sag may occur. The method further includes forgoing executing the engine autostart operation when it is determined that a driveline torque sag will occur during the execution of the engine autostart operation.

Abstract: A powertrain system includes an internal combustion engine having a crankshaft that fixedly couples to an input member of a multi-mode transmission including first and second torque machines. The transmission operates in one of a plurality of fixed-gear modes and variable modes through selective activation of first and second clutches. A control method includes, in response to a command to operate the multi-mode transmission in a fixed-gear mode, activating only the first clutch and commanding the engine to an OFF state. The first torque machine is controlled to generate a first torque output responsive to a drag torque that is offset by an engine reactive torque with the engine in the OFF state. The transmission operates in the fixed-gear mode by controlling the second torque machine to generate a second torque output responsive to an operator torque request and the first torque output of the first torque machine.

Abstract: A powertrain system is described, and includes an internal combustion engine and an electric machine configured to generate propulsion torque responsive to a driver torque request. A method for operating the powertrain system includes determining, in response to a request to execute an engine autostart operation, whether a driveline torque sag may occur. The method further includes forgoing executing the engine autostart operation when it is determined that a driveline torque sag will occur during the execution of the engine autostart operation.

Abstract: A powertrain system includes an internal combustion engine having a crankshaft that fixedly couples to an input member of a multi-mode transmission including first and second torque machines. The transmission operates in one of a plurality of fixed-gear modes and variable modes through selective activation of first and second clutches. A control method includes, in response to a command to operate the multi-mode transmission in a fixed-gear mode, activating only the first clutch and commanding the engine to an OFF state. The first torque machine is controlled to generate a first torque output responsive to a drag torque that is offset by an engine reactive torque with the engine in the OFF state. The transmission operates in the fixed-gear mode by controlling the second torque machine to generate a second torque output responsive to an operator torque request and the first torque output of the first torque machine.

Abstract: A multi-mode powertrain system includes a transmission configured to transfer torque among an internal combustion engine, torque machines and an output member. A method for controlling the powertrain system includes operating the multi-mode powertrain system to execute an engine intake manifold pump down mode, and aborting the engine intake manifold pump down mode and fueling the engine, wherein aborting is based upon intake manifold pressure and system constraints.

Abstract: A method of controlling a powertrain system of a hybrid vehicle includes detecting a request to start an engine, incrementally applying torque to the powertrain system, and biasing the torque against a static member of the powertrain system, such as a parking pawl of a transmission when the transmission is disposed in a parking position, to remove lash from the powertrain system prior to starting the engine.

Abstract: A method to start operation of an internal combustion engine of a hybrid powertrain includes initiating rotation of a crankshaft of the engine with at least one electric machine in accordance with a first ramping profile until a first predetermined speed is achieved in response to an engine start event during a cold start condition. Engine speed is monitored and the engine is fired while controlling the engine speed to maintain the first predetermined speed with the at least one electric machine. The first ramping profile is adjusted at a rate corresponding to an estimated rate at which the engine speed is increasing during the engine firing. When at least one predetermined combustion quality parameter is achieved, the engine speed is controlled in accordance with a second ramping profile until a second predetermined speed is achieved based on controlling combustion parameters of the engine.

Abstract: A powertrain system includes an internal combustion engine configured to execute autostop and autostart operations, and a multi-mode transmission with an electrically-powered hydraulic pump configured to provide pressurized hydraulic fluid to a hydraulic circuit. A Method for controlling operation of the hydraulic pump includes operating the hydraulic pump in a low power mode only when the engine is in an engine-off state, operator inputs to a brake pedal, an accelerator pedal, and a transmission range selector are within allowable states, temperatures of select transmission components are within respective predetermined temperature ranges, and transmission output torque is less than a threshold torque request.

Abstract: A powertrain system includes an internal combustion engine, a multi-mode transmission and a driveline. A method for controlling the powertrain system in response to a command to execute an engine autostart operation during vehicle operation includes executing a clutch-driven engine autostart operation to start the engine upon determining that a present transmission output speed is greater than a minimum output speed for engine operation and upon determining that a selected clutch configured to effect a mechanical coupling between the engine and the driveline is activatable.

Abstract: A multi-mode powertrain system includes a transmission configured to transfer torque among an internal combustion engine, torque machines and an output member. A method for controlling the powertrain system includes operating the multi-mode powertrain system to execute an engine intake manifold pump down mode, and aborting the engine intake manifold pump down mode and fueling the engine, wherein aborting is based upon intake manifold pressure and system constraints.

Abstract: A powertrain system includes an internal combustion engine, at least one electric machine and an electro-mechanical transmission operative to transmit torque to a driveline. A method for controlling the powertrain system includes enabling neutral operation of the transmission in response to an operator input, activating a first clutch coupled to a first planetary gear set, the first planetary gear set which includes a first element, a second element and a third element. Torque commands are coordinated between the engine and a first electric machine to establish a net zero output torque condition. If a violation of the net zero output torque condition is present, slippage of the first clutch is allowed to dissipate net output torque from reacting with the driveline of the powertrain system.

Abstract: A powertrain system includes an internal combustion engine, at least one electric machine and an electro-mechanical transmission operative to transmit torque to a driveline. A method for controlling the powertrain system includes enabling neutral operation of the transmission in response to an operator input, activating a first clutch coupled to a first planetary gear set, the first planetary gear set which includes a first element, a second element and a third element. Torque commands are coordinated between the engine and a first electric machine to establish a net zero output torque condition. If a violation of the net zero output torque condition is present, slippage of the first clutch is allowed to dissipate net output torque from reacting with the driveline of the powertrain system.

Abstract: A powertrain system includes an internal combustion engine, a multi-mode transmission and a driveline. A method for controlling the powertrain system in response to a command to execute an engine autostart operation during vehicle operation includes executing a clutch-driven engine autostart operation to start the engine upon determining that a present transmission output speed is greater than a minimum output speed for engine operation and upon determining that a selected clutch configured to effect a mechanical coupling between the engine and the driveline is activatable.

Abstract: A method to start operation of an internal combustion engine of a hybrid powertrain includes initiating rotation of a crankshaft of the engine with at least one electric machine in accordance with a first ramping profile until a first predetermined speed is achieved in response to an engine start event during a cold start condition. Engine speed is monitored and the engine is fired while controlling the engine speed to maintain the first predetermined speed with the at least one electric machine. The first ramping profile is adjusted at a rate corresponding to an estimated rate at which the engine speed is increasing during the engine firing. When at least one predetermined combustion quality parameter is achieved, the engine speed is controlled in accordance with a second ramping profile until a second predetermined speed is achieved based on controlling combustion parameters of the engine.

Abstract: A powertrain system includes an internal combustion engine configured to execute autostop and autostart operations, and a multi-mode transmission with an electrically-powered hydraulic pump configured to provide pressurized hydraulic fluid to a hydraulic circuit. A Method for controlling operation of the hydraulic pump includes operating the hydraulic pump in a low power mode only when the engine is in an engine-off state, operator inputs to a brake pedal, an accelerator pedal, and a transmission range selector are within allowable states, temperatures of select transmission components are within respective predetermined temperature ranges, and transmission output torque is less than a threshold torque request.

Abstract: A method of controlling a powertrain system of a hybrid vehicle includes detecting a request to start an engine, incrementally applying torque to the powertrain system, and biasing the torque against a static member of the powertrain system, such as a parking pawl of a transmission when the transmission is disposed in a parking position, to remove lash from the powertrain system prior to starting the engine.

Abstract: An engine control system comprises a base air per cylinder (APC) module, a catalyst temperature adjustment module, an ambient temperature adjustment module, and an APC adjustment module. The base APC module determines a base APC to reduce first engine pumping losses during a first deceleration fuel cutoff (DFCO) event relative to second engine pumping losses during a second DFCO event. The catalyst temperature adjustment module determines a catalyst temperature adjustment based on a catalyst temperature during the first DFCO event. The ambient temperature adjustment module determines an ambient temperature adjustment based on an ambient air temperature during the first DFCO event. The APC adjustment module selectively adjusts the base APC based on the catalyst temperature adjustment and the ambient temperature adjustment and controls at least one of the engine airflow actuators based on the adjusted base APC during the first DFCO event.

Abstract: An engine control system comprises a base air per cylinder (APC) module, a catalyst temperature adjustment module, an ambient temperature adjustment module, and an APC adjustment module. The base APC module determines a base APC to reduce first engine pumping losses during a first deceleration fuel cutoff (DFCO) event relative to second engine pumping losses during a second DFCO event. The catalyst temperature adjustment module determines a catalyst temperature adjustment based on a catalyst temperature during the first DFCO event. The ambient temperature adjustment module determines an ambient temperature adjustment based on an ambient air temperature during the first DFCO event. The APC adjustment module selectively adjusts the base APC based on the catalyst temperature adjustment and the ambient temperature adjustment and controls at least one of the engine airflow actuators based on the adjusted base APC during the first DFCO event.

Abstract: A vehicle includes an engine, a controller for turning off the engine when the vehicle is idle, a motor/generator for starting the engine, an inverter for converting a DC auxiliary voltage from a battery into an AC voltage for powering the motor/generator, and a device for isolating a DC voltage from the DC auxiliary voltage to prevent voltage sag in a vehicle system during engine starting. The device includes a transformer, a rectifier/regulator, and an isolator. A mechanical relay opens, or an FET is activated, to isolate the DC voltage during engine start. A method for preventing voltage sag in an auxiliary vehicle system includes detecting a commanded engine start, comparing a measured auxiliary voltage to a threshold, isolating a predetermined DC voltage from a DC auxiliary voltage when the measured auxiliary voltage is less than the threshold, and powering the auxiliary vehicle system using the isolated DC voltage.

Abstract: A vehicle includes an engine, a controller for turning off the engine when the vehicle is idle, a motor/generator for starting the engine, an inverter for converting a DC auxiliary voltage from a battery into an AC voltage for powering the motor/generator, and a device for isolating a DC voltage from the DC auxiliary voltage to prevent voltage sag in a vehicle system during engine starting. The device includes a transformer, a rectifier/regulator, and an isolator. A mechanical relay opens, or an FET is activated, to isolate the DC voltage during engine start. A method for preventing voltage sag in an auxiliary vehicle system includes detecting a commanded engine start, comparing a measured auxiliary voltage to a threshold, isolating a predetermined DC voltage from a DC auxiliary voltage when the measured auxiliary voltage is less than the threshold, and powering the auxiliary vehicle system using the isolated DC voltage.