Methods and systems are provided for controlling clutch capacity in a hybrid electric vehicle. In one example, a method includes adjusting values of a transfer function of a clutch of a dual clutch transmission in response to an operating condition of an engine and/or operating condition of an integrated starter/generator coupled to the engine while a vehicle is propelled via an electric machine coupled to the dual clutch transmission, and maintaining a driver demand wheel torque at vehicle wheels via adjusting torque of the electric machine in response to the operating condition of the engine and/or operating condition of the integrated starter generator. In this way the method may apply pressure to one of the clutches where engine speed is independently controlled to maintain positive or negative slip, thus enabling adaptation of positive and negative clutch transfer functions, which may improve driveline operation and shift quality.

Methods and systems are provided for adjusting clutch pressures and electric machine torques as a function of a stability metric threshold(s) in order to balance performance and charging of an onboard energy storage device. In one example, a method includes during an upshift of a transmission from a first gear to a second gear, adjusting a clutch pressure of the transmission to adjust slippage of a clutch in response to a vehicle stability control parameter exceeding a threshold. In this way, torque delivered to a transmission output shaft may be reduced, which may increase vehicle stability.

A control device that controls a vehicle drive transfer device in which a speed change device that includes a plurality of engagement devices and that selectively establishes one of a plurality of shift speeds with different speed ratios in accordance with a state of engagement of the plurality of engagement devices is provided in a power transfer path that connects between a drive force source and wheels.

Methods and systems are provided for launching a vehicle in an electric-only mode of operation. In one example, a driveline operating method comprises engaging a parking pawl to an output shaft of a dual clutch transmission in response to a request to engine a vehicle into a parked state, and disengaging the parking pawl via rotating an engine via an integrated starter/generator in response to a request to propel the vehicle solely via power of an electric machine positioned downstream of the dual clutch transmission. In this way, the vehicle may be launched in the electric-only mode without activating the engine in a fueled mode of operation and then deactivating the engine, which may increase vehicle operator satisfaction and which may improve fuel economy.

A method and a system for controlling a backlash of a powertrain included in a vehicle in connection with a gear shifting operation is presented. The method comprises: controlling, in connection with a first gear shifting operation, a clutch included in the powertrain to a slipping position, in which slipping position the clutch transfers a slipping torque that is less than a torque being transferred in a closed position for the clutch; analyzing a change of a rotational speed for an input shaft of a gearbox included in the powertrain; determining a position for the clutch, for which position the change of the rotational speed has a value corresponding to a backlash torque, the backlash torque having a predetermined value for eliminating the backlash; and utilizing the determined clutch position for controlling the clutch in connection with a second subsequent gear shifting operation.

A vehicle regenerative speed control device is provided that includes a controller which performs a regenerative speed control for downshifting a belt-type continuously variable transmission to the low gear ratio side and increasing a rotational speed of a transmission input shaft to which a motor generator is connected when there is a request for an increase in the regeneration amount while decelerating. The controller also imposes the limitation of staying within a Pri end command rotational speed change rate for the Pri end command rotational speed when performing a regenerative speed control for increasing the Pri end command rotational speed based on a braking operation in a brake switching region for switching from regenerative braking to hydraulic braking due to a decrease in vehicle speed.

When an inertia phase has started while torque phase control is being executed, the torque phase control is ended, a target torque capacity of an engaging element in inertia phase control is corrected on the basis of a difference between the target torque capacity of the engaging element at the time when the inertia phase has started and the target torque capacity of the engaging element at the time when the torque phase control has completed (or a difference between the target torque capacity of the engaging element at the time when the inertia phase has started and the target torque capacity of the engaging element, which is set at the time when the inertia phase control has started), and the inertia phase control is started.

A vehicle regenerative speed control device is provided that includes a controller which performs a regenerative speed control for downshifting a belt-type continuously variable transmission to the low gear ratio side and increasing a rotational speed of a transmission input shaft to which a motor generator is connected when there is a request for an increase in the regeneration amount while decelerating. The controller also imposes the limitation of staying within a Pri end command rotational speed change rate for the Pri end command rotational speed when performing a regenerative speed control for increasing the Pri end command rotational speed based on a braking operation in a brake switching region for switching from regenerative braking to hydraulic braking due to a decrease in vehicle speed.

A control method of a dual clutch transmission for a hybrid electric vehicle includes: determining, by a transmission controller, whether a vehicle has entered a power-off down-shift state; determining, by the transmission controller, whether a transmission including a first input shaft, a second input shaft, and an output shaft has entered a torque phase, when the first determining step determines that the vehicle has entered the power-off down-shift state; calculating a compensatory torque for compensating for a change in a regenerative braking force according to a change of a gear ratio in accordance with a completion percentage of the torque phase, when it is determined that a transmission has entered the torque phase; and compensating for regenerative torque of a motor by applying the compensatory torque.

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, the engine is started and coupled to the driveline via closing a clutch of a dual clutch transmission. Speed of the engine and clutch pressure are controlled to reduce driveline torque disturbances and provide a desired wheel torque.