Abstract: A vehicle includes an engine, a motor selectively coupled to the engine, a transmission selectively coupled to the motor, and a controller. The motor is able to operate as a motor (to provide torque to the transmission) and a generator (to charge a battery). In one mode, the controller can command the engine to both propel the vehicle and provide torque to the motor to charge the battery. The controller estimates the maximum available engine torque in the current gear and maintains the vehicle in the current gear of the transmission. And, the controller commands the motor to charge the battery by a magnitude based on the difference between driver demanded torque and an estimated maximum available engine torque in a current gear of the transmission. This allows the engine to operate at (or near) its maximum torque output to fulfill driver demands and charge the battery while inhibiting downshifting.

Abstract: A vehicle includes a hybrid powertrain with a motor/generator electrically coupled to a high-voltage bus to provide propulsion. The vehicle also includes an integrated starter/generator electrically copulated to a low-voltage bus and configured to start the engine. A vehicle power system includes a power converter electrically coupled between the high-voltage bus and the low-voltage bus. During engine start events, operation of the integrated starter/generator is coordinated with operation of the power converter to reduce voltage sag on the low-voltage bus. An increase rate of current supplied to the integrated starter/generator is limited such that a current output of the power converter does not saturate at a maximum current output for a period of time after initiating the engine start event.

Abstract: Systems and methods for operating a transmission of a hybrid powertrain that includes a motor/generator are described. The systems and methods may classify transmission degradation in response to an estimated transmission input shaft speed that is determined from transmission output shaft speed. In one example, transmission degradation may be correctable transmission degradation, partial transmission degradation, and continuous transmission degradation.

Abstract: A system and method for estimating disconnect clutch torque during engine start with the motor in vehicles having an engine selectively coupled to the motor and transmission may be configured to control motor torque based on a clutch torque estimated from a difference in a measured powertrain state and a predicted powertrain state using motor torque as an input. The powertrain states may include, for example, motor speed, turbine speed, engine speed and clutch torque. An adaptive gain may be used to drive the difference between measured and estimated clutch torque toward zero.

Abstract: A control strategy is provided for a hybrid vehicle that will increase drivability during low or decreasing driver demands. Coordination between shifting the transmission and stopping or (non-demand) starting of the engine can increase drivability. The vehicle includes a motor/generator with one side selectively coupled to the engine and another side selectively coupled to the transmission. The control strategy acts when an engine start or stop is requested while driver demand is decreasing and a shift of the transmission is demanded. To inhibit these events from proceeding simultaneously, the control strategy delays the engine from starting or stopping until the transmission has finished shifting, or vice versa.

Abstract: A shift strategy is provided for a hybrid electric vehicle to cause a speed of a motor to approach a target motor speed to increase fuel economy for an engine operating in a hybrid drive mode. A controller shifts the transmission according to a magnitude of a driver torque demand, the current rotor or impeller speed, and whether the motor is consuming or producing current. The controller shifts the transmission according to one shift schedule when the motor is motoring, and according to another shift schedule when the motor is generating power.

Abstract: Systems and methods for operating a hybrid powertrain that includes an engine and a motor/generator are described. The systems and methods align in time an estimated motor torque and an actual motor torque to provide an estimated driveline torque. The alignment compensates for communications delays between different controllers over a controller area network.

Abstract: A vehicle is provided with a powertrain including a battery-powered electric motor, an internal combustion engine, a transmission, and a powertrain controller. The controller is programmed to permit an upshift of a transmission gear ratio while a powertrain torque demand is less than a forecasted available powertrain torque sustainable over a predetermined upcoming duration of time. The controller is also programmed to inhibit an upshift while the torque demand exceeds the forecasted available powertrain torque to reduce successive gear shifts. The controller may be further programmed to, in response to battery a state of charge being less than a threshold, reduce the forecasted available powertrain torque by an amount sufficient to provide a recharge to a battery. The controller may be further still programmed to reduce the forecasted available powertrain torque by an amount sufficient to restart the engine while the powertrain is operating in an engine-off traction mode.

Abstract: Methods and systems are provided for improving engine restart operations occurring during a transmission shift in a hybrid vehicle. Engine speed is controller during cranking and run-up to approach a transmission input shaft speed that is based on the future gear of the transmission shift. Engine speed is controlled via adjustments to spark, throttle, and/or fuel, to expedite engine speed reaching the synchronous speed.

Abstract: Systems and methods for operating a hybrid powertrain that includes an engine and a motor/generator are described. The systems and methods adjust battery charging and discharging as well as engine and motor torque based on whether or not the vehicle is operating in a cruise control mode. In one example, curves that provide a basis for operating an engine and motor based on driver demand torque are compressed during a vehicle cruise control mode to improve powertrain efficiency.

Abstract: A system and method for controlling a transmission gear shift in a vehicle having a driveline and an electric motor operable to output torque to the driveline includes applying a negative motor torque to the driveline to reduce driveline oscillations resulting from the transmission gear shift. The negative motor torque is based on vehicle conditions occurring after the transmission gear shift has begun and before the transmission gear shift is complete.

Abstract: Systems and methods for operating a transmission of a hybrid powertrain that includes a motor/generator are described. The systems and methods may improve engine starting during engine starts where little or larger driver demand torques are requested. In one example, engine torque may be commanded to a torque based on a filtered driver demand torque, the filtered driver demand torque filtered based on a position of an accelerator pedal.

Abstract: A method of controlling a vehicle, in which the vehicle includes an engine, a traction motor, and a clutch configured to selectively couple the engine to the motor, includes commanding the traction motor to provide an incremental torque. The motor is commanded to provide the incremental torque in response to the clutch being in a slipping condition. The magnitude of the commanded incremental torque is in response to the lesser of first and second torques. The first torque corresponds to an engine torque, and the second torque corresponds to a clutch torque capacity.

Abstract: A hybrid electric vehicle includes an engine and a traction motor coupled to the engine by a coupling device or a clutch for providing torque to wheels of the vehicle. An inverter is electrically connected to the traction motor. A second coupling device or at least one clutch at least indirectly selectively couples the motor to the drive wheels. A controller controls the second coupling device based upon a temperature of at least one of the traction motor and the inverter.

Abstract: Systems and methods for improving launching of a stopped hybrid vehicle are presented. The systems and methods adjust speed of a motor to reduce the possibility of noticeable impact between driveline gears during vehicle launch. In one example, motor speed is adjusted to a pump pressurization speed where driveline components may be moved to reduce impact between driveline gears during vehicle launch.

Abstract: Systems and methods for operating a transmission of a hybrid powertrain that includes a motor/generator are described. The systems and methods may adjust one or more actuators in response to an estimated transmission input shaft speed that is determined from transmission output shaft speed. The one or more actuators may include a transmission clutch, the motor/generator, or a gear selection solenoid.

Abstract: Methods and systems are provided for improving engine restart operations responsive to a heavy operator pedal tip-in. Engine torque and disconnect clutch capacity are controlled during cranking and engine speed run-up so as to provide excess torque to accelerate the engine to the motor speed and prepare the engine for elevated torque delivery after the engine connects to the driveline. At a time of connecting the engine to the driveline, the engine torque is transiently reduced to avert NVH issues related to engine speed overshooting or undershooting the target speed.

Abstract: Systems and methods for operating a transmission of a hybrid powertrain that includes a motor/generator are described. The systems and methods may classify transmission degradation in response to an estimated transmission input shaft speed that is determined from transmission output shaft speed. In one example, transmission degradation may be correctable transmission degradation, partial transmission degradation, and continuous transmission degradation.

Abstract: A system and method for controlling a transmission gear shift during a braking event in a vehicle having an electric motor and friction brakes both operable to brake the vehicle includes the step of reducing friction braking to increase wheel torque during the braking event. The braking event includes both friction braking and regenerative braking The reduction in friction braking to increase the wheel torque is based at least in part on a reduction in the wheel torque resulting from a change in gear ratio of a step-ratio transmission during the transmission gear shift.

Abstract: A method includes controlling a torque output of an electric machine of an electrified vehicle based on estimated loads present during a transmission engagement of the electrified vehicle. Controlling the torque output may include merging a first feed-forward torque with a feedback torque if an input shaft of a transmission gearbox is spinning, or merging a second, different feed-forward torque with the feedback torque if the input shaft is not spinning.