A vehicle powertrain includes an engine and a transmission coupled to the engine. The transmission has a first neutral state in which a first combination of clutches are engaged and a second neutral state in which a second combination of clutches are engaged. A vehicle controller is programmed to, in response to the transmission being in the first neutral state and an engine-torque request exceeding a threshold value, shift the transmission to the second neutral state.

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 controller commands an engine torque level in response to a driver demanded torque based on an accelerator pedal position. If the driver demanded torque decreases rapidly during or just prior to a torque phase of a shift, the controller commands the engine to temporarily generate torque exceeding the driver demand. The controller sets a nominal engine torque equal to the driver demand torque before the rapid decrease, slowly decreases the nominal engine torque during the torque phase, and decreases the nominal torque at progressively faster rates during the inertia phase to bring the nominal torque back into agreement with the driver demanded torque. The commanded engine torque is based on the nominal torque, but may be less than the nominal torque during the inertia phase to permit the engine speed to decrease faster.

A vehicle lock-up clutch control device includes a torque converter, a fuel cutoff control unit and a lock-up release/transmission cooperative control unit. The torque converter is disposed between an engine and a continuously variable transmission. The fuel cutoff control unit is configured to prevent fuel injection to the engine while in a coasting state with the driver's foot away from the accelerator, and configured to restart the fuel injection based on a fuel recovery permission. The lock-up release/transmission cooperative control unit is configured to carry out a cooperative control of a lock-up release control for reducing the clutch engagement capacity of the lock-up clutch and a transmission control for shifting the transmission. Then, if there is an accelerator depression operation while coasting with the lock-up clutch in an engaged state, the lock-up release timing and the shift timing are offset from one another.

The present disclosure provides a shift control method for a hybrid vehicle with a DCT that includes: a shifting state-determining step in which a controller determines whether an inertia phase of power-off down-shift is entered; a motor torque-adjusting step that request to reduce regenerative braking torque of a motor as much as a predetermined requested reduction amount, when the controller determines that the inertia phase has been entered in the shifting state-determining step; and a clutch torque-reducing step that ends the motor torque-adjusting step and reduces torque of an engagement clutch, when the requested reduction amount of the regenerative braking torque of the motor is less than zero while the controller performs the motor torque-adjusting step.