Abstract: A control system for a modular hybrid electric vehicle operates an internal combustion engine at a torque level above the driver demanded torque improving the engine's efficiency. A traction motor driveably connected to the engine is operated at a torque level such that the combined torque satisfies the driver demand. The traction motor torque is limited to avoid inefficient combinations of speed and torque at which the motor is inefficient. During idle operation, the traction motor is operated at a torque determined from a battery state of charge and the engine is operated to maintain a predetermined speed. If the engine speed drops below a threshold, motor torque is adjusted to reduce the load on the engine to avoid stalling.

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: A hybrid powertrain includes a traction battery and a controller. The controller is programmed to, responsive to a current vehicle speed exceeding a first threshold, reduce a parameter indicative of state of charge (SOC) of the battery by an offset amount that varies with an amount of predicted distance for which a predicted vehicle speed profile is less than a second threshold to prompt charging of the battery to increased SOC values.

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 vehicle includes an engine having a crankshaft, a transmission, an electric machine, and at least one controller. The transmission includes a torque converter having a turbine fixed to a turbine shaft that is driveably connected to driven wheels of the vehicle. The torque converter includes an impeller and a bypass clutch configured to selectively lock the impeller and the turbine relative to each other. The electric machine includes a rotor selectively coupled to the crankshaft via a disconnect clutch and fixed to the impeller. The at least one controller is configured to generate a first torque command for the electric machine that defines a magnitude equal to driver-demanded torque while the bypass clutch is locked. The controller is further configured to, in response to a reduction in fluid pressure supplied to the bypass clutch, generate a second torque command for the electric machine that defines a magnitude equal to driver-demanded torque plus impeller inertia torque.

Abstract: A method according to an exemplary aspect of the present disclosure includes, among other things, controlling a torque output of an electric machine of an electrified vehicle during a vehicle creep condition, the torque output calculated based at least on a road grade estimate and a vehicle mass estimate.

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: A vehicle includes an engine and an electric machine coupled to a gearbox. A controller is programmed to predict, at an onset of a shift, a supplemental torque profile to fill a torque hole expected during the shift and an available electric machine torque during the shift. The controller is further programmed to, in response to the supplemental torque profile exceeding the available electric machine torque during the shift, operate the engine from the onset to achieve a torque reserve in anticipation of increasing the engine torque.

Abstract: A hybrid electric vehicle having a motor and an engine that are selectively connected on a driveline and controlled by a controller. The controller is configured to schedule additional motor torque to compensate for engine inertia drag based upon a clutch pressure value and a clutch slip speed value during a period of clutch engagement. The controller is also configured to maintain vehicle acceleration using a proportional integral controller to adjust the motor torque during a period of clutch engagement.

Abstract: A hybrid electric vehicle has a powertrain including an internal combustion engine, an electric machine, and a transmission coupled to controller(s) that control torque disturbances arising from changing output torques of the engine, electric machine, and transmission. A torque disturbance threshold is adjusted for driver comfort, and is used to respond to torque demand signals from the vehicle systems, including a battery charging subsystem, and a driver. The controller(s) respond to battery charge and driver demand torque signals, among others, and adjust engine and electric machine torque at a controlled rate and magnitude, using charge-torque-slew-rate, charge-torque, and other limits. Battery charging is similarly managed.

Abstract: A vehicle having an engine, a starter-generator, and a controller is disclosed. The controller is configured to respond to an engine start command, operate the engine to produce excess torque beyond a demand torque, and in response to engine speed achieving a threshold, operate the starter-generator to load the engine to consume the excess torque and drive the engine speed toward an electric machine speed, and engage a clutch to couple the engine and an electric machine.

Abstract: A hybrid electric vehicle having a powertrain including an engine and an electric machine, and controllers configured to derate powertrain output torque below a nominal maximum to a fault-torque limit, in response to a vehicle fault or issue. The vehicle and controllers are also configured to transiently increase powertrain torque output above the fault-torque limit in response to a torque demand that exceeds the limit, and which is needed to enable a predicted vehicle maneuver. The controller also establishes a predicted duration for the predicted interim vehicle maneuver and for override of the fault-torque limit and delivery of the additional torque from the torque-demand signal and other signals. The predicted duration includes a time span to maneuver through roadway obstacles and traffic, but does not exceed a limited operation time or a limited power output established by the controller from the vehicle issue or fault identified by the fault signal.

Abstract: Systems and methods for operating a driveline of a hybrid vehicle are disclosed. In one example, powertrain output is limited or constrained so that powertrain output variation is limited to a desired level at different altitudes. The powertrain output may be constrained based on a ratio of a threshold electric machine torque to a threshold engine torque.

Abstract: A vehicle includes an engine, electric machine, starter-generator, and a controller. The engine and electric machine are each configured to propel the vehicle. The starter-generator is coupled to the engine and is configured to adjust engine speed during an engine start-up event. The controller is programmed to, in response to engine speed increasing towards a target speed during an engine start-up event, generate a target drag torque with the starter-generator to reduce overshoot of the target engine speed.

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.

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: An electrified vehicle includes a transmission system including a differential and an electrically powered heating device configured to selectively warm a differential fluid of the differential. The electrically powered heating device is selectively powered to warm the differential fluid.

Abstract: A system and method for controlling a vehicle powertrain including an engine and a motor operable to propel the vehicle includes reducing a torque of the motor at a first torque reduction rate from a torque level above a minimum motor torque in response to a deceleration request. A torque of the engine is reduced at a second torque reduction rate less than the first torque reduction rate in response to the deceleration request.

Abstract: A control system is provided to account for differences in engine response times and motor response times during an upshift in a transmission. A vehicle includes a driveline that has an engine, a traction motor, and a transmission selectively connected in series. A control area network (CAN) connects a plurality of controllers. At least one of the controllers is programmed to, during an upshift in the transmission, output signals over the CAN to reduce torque of the traction motor. The controller also reduces the engine torque based on signal delays in the CAN.

Abstract: According to one embodiment of this disclosure, a vehicle having an electric machine and at least one controller is described. The electric machine may be configured to generate creep torque to move the vehicle. The controller may be programmed to decrease a target speed of a torque converter impeller to create a desired brake torque and partially cancel the creep torque without application of friction brakes in response to a brake pedal being pressed while an accelerator pedal is not being pressed.