Systems and methods for improving operation of a driveline disconnect clutch for a hybrid vehicle shifting are presented. In one example, pressure of a working fluid supplied to the driveline disconnect clutch is adjusted in response to a rate of change in accelerator pedal position. Further, pressure of the working fluid may be decreased responsive to selected operating conditions.

A drive force control system to improve efficiency of a vehicle by controlling motors connected to drive wheels. A controller is configured to: calculate a total required torque of the drive unit; obtain combinations of a first interim torque of a first motor and a second interim torque of a second motor to achieve the total required torque; select a combination of the first interim torque and the second interim torque to minimize an output of a power source; and output the first interim torque of the first motor and the second interim torque of the second motor based on the selected combination.

A slip control method and arrangement for a driveline is described herein. The driveline includes a clutch that is so controlled as to slip when a torque higher than the usable torque attempts to pass through. Accordingly, the clutch prevents the prime mover from stalling.

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, inertia torque compensation is provided to counter inertia torque during a power-on upshift.

In a hybrid vehicle control system, when a first traveling mode using torque of an electric motor is switched to a second traveling mode using torque of an engine, a controller performs an engine start control by applying an engagement pressure to a first clutch and by cranking the engine by the electric motor, so as to start the engine. Specifically, the controller obtains a predicted start time and an actual start time by the engine start control, and corrects the engagement pressure so as to decrease the engagement pressure applied to the first clutch at a subsequent time of starting the engine, when the actual start time is shorter than the predicted start time.

Systems and methods for operating an engine and a driveline disconnect clutch are presented. In one example, a transient vehicle maneuver that may allow at least some air to be drawn into an oil pump pickup tube may be detected. Engine torque may be reduced and a pump output command may be increased responsive to the transient vehicle maneuver.

A method for operating a vehicle that includes a driveline disconnect clutch is described. In one example, the method includes adjusting a pressure of the driveline disconnect clutch as a function of an engine pull-up torque minus a driver demand torque when the pressure of the driveline disconnect clutch is between a torque stroke pressure and a hydraulic stroke pressure.

A control system for a hybrid vehicle configured to prevent an excessive drop in an engine speed and while reducing vibrations when decelerating the vehicle abruptly. When an abrupt decelerating operation is detected in the fixed mode, a controller shifts an operating mode from the fixed mode to the high mode or the low mode by disengaging one of engagement devices in which a torque applied thereto in the fixed mode is reduced smaller by an inertia torque of the motor resulting from the decelerating operation.

Presented are hybrid electric vehicle (HEV) powertrains and control logic for vehicle response management, methods for making/operating HEV powertrains, and motor vehicles equipped with HEV powertrains. A method of controlling a hybrid powertrain includes receiving data indicative of a motor speed of a traction motor and torque commands for the motor, an engine, and an engine disconnect clutch (EDC). A vehicle controller uses a state observer module to estimate a jerk response based on the motor speed, and determines if the EDC is in a torque-transmitting active state. Responsive to the EDC being in the active state, the controller calculates an incremental feedback control signal that is predicted to reduce the estimated jerk based on the engine, motor, and clutch torque commands. One or more torque command signals are transmitted to the engine, motor and/or EDC to modulate a torque output thereof based on the incremental feedback control signal.

An engine clutch disengagement control method for a hybrid electric vehicle is disclosed to overcome a sense of discontinuous travel caused when an engine clutch is disengaged due to influence of the inaccuracy of model engine torque. The method includes: acquiring vehicle acceleration information during engine clutch disengagement control of the hybrid electric vehicle, determining whether a predetermined condition for determining inaccuracy of model engine torque required for engine clutch disengagement control is satisfied from the acquired vehicle acceleration information, when the predetermined condition is satisfied, determining a situation in which the model engine torque is inaccurate and calculating target compensation torque using the vehicle acceleration information, calculating a target slippage amount in a transmission clutch using the calculated target compensation torque, and performing transmission clutch torque control for inducing slippage in a transmission clutch based on the target slippage amount and a current transmission speed.