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 six-speed includes first and second input shafts and on which drive gears are disposed, an idler shaft on which idler drive gears are disposed, and first and second output shafts on which driven gears are disposed. The whole length of the DCT is formed such that an upper whole length section is reduced by the length of a second output shaft that is reduced by disposing the sixth-speed and reverse driven gears on the second output shaft, or an intermediate whole length section formed between the upper and lower whole length sections is reduced by the length of the first input shaft that is reduced by disposing the fifth-, sixth- and reverse driven gears on the second output shaft.

A power transmission system for a vehicle includes: an engine; input shafts, at least one of which configured to selectively engage with the engine, each of the input shafts being provided with a shift driving gear thereon; output shafts, each of the output shafts being provided with a shift driven gear configured to mesh with a corresponding shift driving gear; a motor power shaft configured to rotate together with one of the output shafts; and a first motor generator configured to rotate together with the motor power shaft, wherein when the motor power shaft is rotated together with one of the output shafts, the first motor generator is configured to generate electric power utilizing at least parts of power generated by the engine while the vehicle in a running state or a parking state. A vehicle including the power transmission system is also provided.

A power transmission system for a vehicle includes: an engine; input shafts, each of the input shafts being provided with a shift driving gear thereon; output shafts, each of the output shafts being provided with a shift driven gear configured to mesh with a corresponding shift driving gear; a generator gear fixed on one of the output shafts; a reverse output gear configured to rotate together with or to disengage from a shift driving gear; an output idler gear configured to engage with one of the output shafts so as to rotate together with the output shaft or disengage from the output shaft so as to rotate with the output shaft at different speeds; a motor power shaft configured to rotate together with the generator gear; and a first motor generator configured to rotate together with the motor power shaft. A vehicle including the power transmission system is also provided.

A power transmission system of a hybrid electric vehicle uses an engine and a motor/generator as power sources, and includes: a torque converter including a planetary gear set having first, second, and third rotating elements, the first rotating element being selectively connected to a transmission housing, the second rotating element being connected to an engine output shaft of the engine, and the third rotating element being connected to a motor output shaft of the motor/generator; an input device including a first input shaft selectively connected to the motor output shaft through one clutch and a second input shaft that is disposed on a same shaft line as the first input shaft to be selectively connected to the motor output shaft through another clutch; and a shift output device shifting and outputting rotation power of the input device.

The present disclosure provides a clutch control method of a hybrid vehicle of the including an entering condition determining step in which a controller determines whether shifting is being performed during regenerative braking; an error calculating step in which the controller calculates a torque error by subtracting observer torque, which is clutch transfer torque calculated by a clutch torque estimator receiving transmission input torque and motor speed, from map torque, which is clutch transfer torque calculated based on a clutch transfer torque map for clutch actuator strokes learned in advance, when shifting is being performed during regenerative braking; a correcting step in which the controller corrects the clutch transfer torque map for the clutch actuator strokes using the torque error calculated in the error calculating step; and a clutch control step in which the controller controls a clutch using the map corrected in the correcting step.