A method for learning a touch point of an engine clutch of a hybrid electric vehicle including a motor connected to a transmission and an engine selectively connected to the motor through the engine clutch includes determining whether a learning condition of the touch point of the engine clutch is satisfied, releasing a transmission clutch and controlling a motor speed when the learning condition is satisfied, increasing a coupling pressure of the engine clutch when a change amount of the motor speed is less than a first predetermined value, comparing a change amount of a motor torque according to the increased coupling pressure of the engine clutch with a second predetermined value, and learning the touch point of the engine clutch when the change amount of the motor torque is greater than or equal to the second predetermined value.

A method for learning a clutch pedal may include determining whether a clutch pedal is operated; determining at least one of a depressed speed of the clutch pedal, a depressed value of the clutch pedal, and a speed of an engine at a shifting timing when the clutch pedal is operated; determining at least one of a moving average value of the depressed speed of the clutch pedal, a moving average value of the depressed value of the clutch pedal, and a moving average of the speed of the engine for a predetermined time; and storing the moving average value as a correction value for preventing an abrasion of a shift clutch.

A fail-safe control method and apparatus for an engine clutch actuator includes determining whether a driving mode of a hybrid vehicle is an electric vehicle (EV) mode. An oil pressure in a cylinder of the engine clutch actuator is measured when the driving mode of the hybrid vehicle is the EV mode. The oil pressure value in the cylinder is compared with a previously stored average pressure value. A motor of the engine clutch actuator rotates to decrease the oil pressure value in the cylinder t when the oil pressure value in the cylinder is greater than the previously stored average pressure value. An engine clutch is connected to an internal combustion engine as the oil pressure value in the cylinder decreases.

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.

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.

Methods and systems are provided for operating a driveline of a hybrid vehicle powertrain, where the driveline includes an electric machine downstream of a dual clutch transmission, which is downstream of an engine. In one example, a method comprises communicating from a transmission, a torque to accelerate transmission components from a first speed to a second speed with first and second clutches of a dual transmission open, the communicating performed while an electric machine coupled to the dual clutch transmission at a location downstream of the dual clutch transmission is providing torque to propel a vehicle. In this way, wheel speed may remain substantially constant while the transmission is shifted and the engine is stopped.

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 entering into a parked state in a hybrid electric vehicle that includes a dual clutch transmission. In one example, a driveline operating method comprises in response to a first condition, engaging a first gear and engaging a second gear of a dual clutch transmission in response to a request to enter a vehicle park state where an output of a transmission is held from rotating, and in response to a second condition, engaging a third gear and engaging a fourth gear of a dual clutch transmission in response to a request to enter a vehicle park state. In this way, a park state may be entered into without the use of a park pawl, which may reduce costs associated with the vehicle and which may prevent issues associated with degradation of the park pawl.

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 comprises 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 method for learning an engine clutch kiss point of a hybrid vehicle includes: controlling, by a controller, an engine clutch which connects an engine with a motor or disconnects the engine from the motor so that the engine clutch is engaged after the controller checks stop of the engine and of the motor and stabilization operation for a hydraulic pressure line of the engine clutch is performed; controlling the motor to have a certain speed after the stabilization operation; controlling the engine clutch to be engaged after speed of the motor is stabilized; determining whether torque variation of the motor when the engine clutch is engaged is equal to or greater than a threshold value; and determining a hydraulic pressure at which the torque variation is the threshold value as the kiss point of the engine clutch.