Abstract:
A vehicle system may include a controller configured to increase, after a specified delay, an engagement pressure of a torque converter clutch prior to occurrence of the event to a target pressure that is based on a regenerative braking torque estimate associated with the event such that a portion of energy associated with the event is converted to electricity. The controller may increase the engagement pressure in response to an accelerator pedal release and an expected regenerative braking event.
Abstract:
Methods and systems are provided for operating a driveline of a hybrid vehicle that includes an internal combustion engine, an electric machine, and a transmission are described. In one example, gears of a transmission may be unlocked from layshafts while an engine is stopped to conserve energy. Alternatively, the gears may be locked and unlocked from layshafts in response to vehicle operating conditions while the engine is stopped to improve driveline response.
Abstract:
Methods and systems are provided for operating a driveline of a hybrid vehicle that includes an internal combustion engine, a rear drive unit electric machine, an integrated starter/generator, and a transmission are described. In one example, charging of an electric energy storage device may be allocated between the rear drive unit electric machine and the integrated starter/generator to increase charge stored in the electric energy storage device.
Abstract:
A vehicle includes a powertrain and at least one controller programmed to, in response to a brake request and a shaft speed associated with a speed of the vehicle achieving a starting speed that is defined by a torque of the powertrain that changes with brake demand at a given shaft speed, reduce a regenerative torque limit that constrains regenerative braking torque over a blend-out duration based on the shaft speed.
Abstract:
A vehicle includes a starter motor, an engine having an output mechanically coupled to the starter motor, a transmission having an input, and an electric machine mechanically coupled to the transmission input. The vehicle further includes a clutch configured to mechanically couple the electric machine and the output of the engine, and at least one controller. The at least one controller is programmed to initiate an engine start based on driver demand. The controller is further configured to enable pressure to the clutch for the engine start if driver demand is less than a calibratable torque value or enable the starter motor for the engine start if the driver demand is greater than a calibratable torque value. The controller may lock the clutch to the output of the engine in response to the speed of the engine being approximately equal to the speed of the electric machine.
Abstract:
A vehicle includes a traction motor coupled to a driveline. An engine and a generator are coupled to the driveline through a planetary gearset. A controller commands the traction motor torque based on a difference between a driver torque demand and an estimated powertrain torque. The estimated powertrain torque is based on an error between actual and estimated engine speed and an error between actual and estimated generator speed. The estimated powertrain torque may be further based on commanded or estimated engine torque and generator torque. The estimated powertrain torque may utilize a state estimator to calculate internal states based on the errors.
Abstract:
A vehicle control system includes a controller that is programmed to, in response to an accelerator lift-pedal event, generate a drag torque, with at least one of an engine and electric machine, having a magnitude that is based on a deceleration fuel shut-off torque of the engine and a desired power output of the electric machine, and limit the drag torque to a threshold value that is based on the deceleration fuel shut-off torque.
Abstract:
A control strategy for a hybrid electric vehicle powertrain having an engine, a motor, and a transmission includes operating the powertrain according to a motor power loss term that is adapted based on battery power supplied to the motor, motor power output, and an estimated motor power loss such that the motor power loss term changes over time and converges to a constant value to thereby be indicative of actual motor power loss.
Abstract:
A vehicle includes an engine, an electric machine, a torque converter and a controller. The torque converter includes an impeller and receives power from the engine and electric machine. The controller, in response to an absence of driver demanded torque and a difference between desired and estimated impeller speeds, adjusts a torque of the electric machine based on a difference between an estimated engine torque and a desired impeller torque in order to drive the impeller toward the desired impeller speed.
Abstract:
A vehicle includes an engine and at least one controller. A first engine cycling command based on route information and a second engine cycling command independent of route information are generated. The engine transitions state according to the first engine cycling command when the second engine cycling command permits the transition. When a first engine cycling profile based on route information includes at least a number of engine cycles, the engine is cycled according to the first engine cycling profile, otherwise, the engine is cycled according to an engine cycling state derived independent of route information. The vehicle includes a traction battery. A state of charge of the traction battery is controlled according to a target state of charge that is derived using route information and a base battery power reference that is independent of route information.