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 powertrain comprising an engine, a motor, a disconnect clutch connected between the engine and the motor, and a transmission. The transmission is connected to the motor by a torque converter and lock-up clutch and selectively and indirectly connected to the engine by the disconnect clutch. A controller receives an engine torque output signal and reduces the torque output of the engine to the clutch capacity limit value. A system and a method are also provided for controlling a powertrain for a hybrid vehicle.
Abstract:
A vehicle includes an electric machine, battery, torque converter bypass clutch, drive wheel, and controller. The electric machine is configured to recharge the battery via regenerative braking. The torque converter bypass clutch is disposed between the electric machine and the drive wheel. The controller is programmed to, in response to a negative drive wheel torque command during a regenerative braking event, adjust a closed-state torque capacity of the torque converter bypass clutch based on the torque command.
Abstract:
A vehicle includes an engine and electric machine connected to a planetary gear, a one-way clutch, and a controller. The one-way clutch transfers torque from the planetary gear to an overdrive gear. The controller, in response to a condition requiring disengagement of the one-way clutch, increases a torque of the electric machine based on a torque command for the electric machine and the torque transferred from the planetary gear to the overdrive gear.
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 vehicle includes a generator, a battery, a transmission, and a controller. The generator is configured to recharge the battery at a maximum power output when a generator speed is above a threshold speed. The transmission is configured to downshift during regenerative braking such that the generator speed is maintained above the threshold speed. The controller is programmed to, in response to a decrease in battery temperature corresponding to a decrease in generator speed required to maintain the maximum power output, decrease the threshold speed.
Abstract:
A system and method for controlling a step-ratio transmission gearshift during a regenerative braking event for a hybrid vehicle having an engine selectively coupled to an electric machine and an automatic transmission control transmission input torque based on a measured shift profile and a target shift profile. A torque trim term may be added to the transmission input torque or electric machine output torque in response to a difference between the measured and target shift profiles. The torque trim term may be used to modify the transmission input torque to speed the shift up or shorten the shift time if the measured shift is progressing too slowly. Likewise, the torque trim term may be used to reduce the transmission input torque or electric machine output torque if the shift is progressing too quickly relative to the target shift profile.
Abstract:
A vehicle includes a powertrain having an electric machine, and friction brakes configured to resist rotation of a vehicle wheel. The further includes at least one controller programmed to (i) issue a command for the electric machine to apply a regenerative torque to decelerate the vehicle in response to driver braking demand, and (ii) cause both a decay in the regenerative torque and a countervailing increase in the resistance of the friction brakes when vehicle speed is reduced to less than a first threshold such that braking demand is substantially satisfied by only the friction brakes when the vehicle speed is less than a second threshold.
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 vehicle includes and an engine, a motor, a transmission, and a controller. The transmission is configured is to receive power from the engine and the motor. The transmission is also configured to shift between gears based on a shift schedule. The controller is programmed to, in response to only the motor providing power to the transmission, adjust the shift schedule to narrow an operating speed range of the motor such that the motor speed maintains a peak range of an available motor power output.