Abstract: A control system including a method and apparatus for operating a hybrid vehicle. A disconnect clutch selectively separates an electric machine from a combustion engine. If a wide open throttle or high torque command is requested and the combustion engine is shut down, a 12 volt starter may be used to start the combustion engine while disconnected from the electric machine and all of the electric machine torque available may be used for traction.

Abstract: A vehicle includes a powertrain having an electric machine operatively coupled to a transmission and selectively coupled to an engine, and a controller. The controller, while operating the powertrain in an electric mode and in response to an accelerator pedal position initiating a transmission ratio change that results in a request to operate the powertrain in a hybrid mode and an engine start fault, outputs a cancellation request to cancel the transmission ratio change.

Abstract: A method of operating a hybrid electric vehicle coordinates operation of an internal combustion engine, a motor, and friction brakes to mitigate a driveline lash crossing without delaying generation of negative torque. In response to a request to transition from positive torque to negative torque, the engine and motor are controlled to rapidly reduce powertrain torque to a small positive value, slowly reduce powertrain torque through the driveline lash zone, and then rapidly reduce powertrain torque to the target. To avoid delay, the friction brakes are applied in a coordinated manner to supply the negative torque during the transition.

Abstract: A vehicle includes a power source, such as an engine, an electric machine, or combination thereof. A torque converter is selectively coupled to the power source such that drive torque can be altered before being distributed into a transmission of the vehicle. A torque converter bypass clutch enables torque from the power source to selectively transmit directly to the transmission with little or no torque altering provided by the torque converter. At least one controller in the vehicle is in communication with a storage device. The controller sends road condition data to the storage device regarding a road segment. During a subsequent drive to or over the road segment, the controller receives the road condition data and enables the torque converter bypass clutch to slip to dampen driveline disturbances when the vehicle passes over the road segment.

Abstract: A vehicle includes a powertrain having an electric machine operatively coupled to a transmission and selectively coupled to an engine, and a controller. The controller, while operating the powertrain in an electric mode and in response to an accelerator pedal position initiating a transmission ratio change that results in a request to operate the powertrain in a hybrid mode and an engine start fault, outputs a cancellation request to cancel the transmission ratio change.

Abstract: A hybrid vehicle powertrain includes an internal combustion engine, first and second electric machines, traction wheels, and an output shaft having meshing gears configured to establish a final drive ratio between the output shaft and the traction wheels. The powertrain additionally includes a first mechanical linkage and a second mechanical linkage. The first mechanical linkage is configured to selectively transmit engine torque to the fraction wheels and selectively transmit electric machine torque to the traction wheels. The second mechanical linkage is configured to selectively transmit engine torque to the traction wheels. When transmitting engine torque to the wheels, the second mechanical linkage defines a fixed overdrive speed relationship between the engine and the fraction wheels.

Abstract: A control system and method for a hybrid electric vehicle powertrain supplies battery power boost torque to vehicle traction wheels to modify shift points for a multiple ratio transmission in the powertrain. A shift schedule is adjusted to avoid a downshift for small changes in torque demand, thus reducing shift frequency due to small transient changes in torque demand.

Abstract: A control system including a method and apparatus for operating a hybrid vehicle. A disconnect clutch selectively separates an electric machine from a combustion engine. If a wide open throttle or high torque command is requested and the combustion engine is shut down, a 12 volt starter may be used to start the combustion engine while disconnected from the electric machine and all of the electric machine torque available may be used for traction.

Abstract: A vehicle includes an engine, a traction motor, a clutch, and a controller. The clutch selectively couples the traction motor to wheels. The controller, in response to a torque output by the fraction motor achieving a torque limit while operating to partially satisfy a demand for driveline damping and while the clutch is locked, slips the clutch to completely satisfy the demand for driveline damping.

Abstract: A hybrid electric vehicle having a discrete ratio transmission shifts according to distinct shift schedules in various operating modes. For example, different shift schedules may be used for operating with the engine off, operating with the engine running, and regenerative braking. When the vehicle transitions from one mode to another, the new shift schedule may schedule a shift that the driver would not expect. To avoid annoying the driver, a control strategy inhibits the shift until either the old strategy would also schedule a shift or a customer event occurs.

Abstract: A method for controlling a hybrid electric powertrain includes, in response to a request to increase a powertrain braking force on at least one of a plurality of traction wheels, (i) commanding at least one clutch to increase a gear ratio of a transmission, and (ii) during clutch stroke, commanding an electric machine to act as a generator such that the electric machine applies a braking force to at least one of the traction wheels.

Abstract: A vehicle includes a motive power source, a transmission, and a clutch system. The vehicle further includes a controller that causes the clutch system to generate a generally constant clutch pressure to mechanically couple the motive power source and transmission as a line pressure associated with the transmission varies.

Abstract: In response to a transmission upshift command and a transmission element speed being greater than a threshold, a controller may reduce a rate of engine air intake prior to initial engagement of an oncoming shift element, at least until a target speed ratio is achieved. This reduction may reduce a transmission input torque such that upshift driveline disturbances are reduced.

Abstract: A vehicle transmission system having a combustion engine, an electric motor and a transmission includes a first clutch operatively connected between the engine and the motor and a one way clutch. The one way clutch is connected in parallel with the first clutch that permits the engine to increase speed with the clutch disengaged until the engine speed matches the motor speed. The engine provides positive torque through the one way clutch to the motor and transmission upon matching the motor speed. The first clutch and the one way clutch may be a hybrid rocker one way clutch.

Abstract: A method for controlling a hybrid electric powertrain includes, in response to a request to increase a powertrain braking force on at least one of a plurality of traction wheels, (i) commanding at least one clutch to increase a gear ratio of a transmission, and (ii) during clutch stroke, commanding an electric machine to act as a generator such that the electric machine applies a braking force to at least one of the traction wheels.

Abstract: A parallel hybrid electric vehicle discrete step-ratio automatic transmission shift strategy attempts to cause a speed of a motor to approach a target motor speed to increase fuel economy for a coupled engine when in hybrid 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.

Abstract: A vehicle includes a motive power source, a transmission, and a clutch system. The vehicle further includes a controller that causes the clutch system to generate a generally constant clutch pressure to mechanically couple the motive power source and transmission as a line pressure associated with the transmission varies.

Abstract: A vehicle includes a power source, such as an engine, an electric machine, or combination thereof. A torque converter is selectively coupled to the power source such that drive torque can be altered before being distributed into a transmission of the vehicle. A torque converter bypass clutch enables torque from the power source to selectively transmit directly to the transmission with little or no torque altering provided by the torque converter. At least one controller in the vehicle is in communication with a storage device. The controller sends road condition data to the storage device regarding a road segment. During a subsequent drive to or over the road segment, the controller receives the road condition data and enables the torque converter bypass clutch to slip to dampen driveline disturbances when the vehicle passes over the road segment.

Abstract: A vehicle includes a powertrain having an electric machine configured to selectively apply regenerative braking torque to decelerate the vehicle. The vehicle also includes a controller programmed to control a rate of change of a regenerative braking torque limit during a transmission downshift that occurs during a regenerative braking event based on a change in speed of an output shaft of the powertrain caused by the transmission downshift.

Abstract: A vehicle includes an engine and a traction motor. A clutch is configured to selectively mechanically couple the engine to the traction motor. A controller or controllers are provided that are configured to command a change in magnitude of an electric current supplied to the electric machine. The command is made in response to initiation of the clutch engaging the traction motor to the engine. The change in magnitude of the electric current ensures the speed of the traction motor remains generally constant during clutch engagement while a speed of the engine is less than that of the traction motor.