A system and method for controlling a powertrain, comprising an internal combustion engine connected to a double clutch transmission having a first and a second partial transmission with at least one shiftable transmission stage. A first friction clutch is arranged between the internal combustion engine and the first partial transmission, and a second friction clutch is arranged between the internal combustion engine and the second partial transmission. An engine torque of the internal combustion engine is transmitted by the first and second friction clutches to the first or second partial transmissions to provide a drivetrain torque at the output of the double clutch transmission. The powertrain is monitored for an occurrence of juddering oscillations, wherein in response to juddering oscillations being detected a regeneration process of one of the first and second friction clutches is triggered, and a friction lining is removed in the regeneration process.

A vehicle may include a dual clutch transmission that adjusts a travel speed of the vehicle based on clutch torque, a brake that makes the vehicle slow down to reduce the travel speed of the vehicle, and a controller that sets a target speed of the vehicle and controls the dual clutch transmission and the brake to allow the travel speed of the vehicle to follow the set target speed.

Systems and methods for operating a hybrid powertrain that includes an engine and a motor/generator are described. The systems and methods provide a way of estimating driveline disconnect clutch torque so that driveline torque disturbances may be reduced. In one example, driveline disconnect clutch torque capacity and engine torque may be a basis for estimating driveline disconnect clutch torque.

Disclosed is a downshift control method for a hybrid DCT vehicle. The method includes: determining, by a controller, whether a downshift is desired while a vehicle travels on a slope having equal to or more than a predetermined reference gradient; comparing, by the controller, a motor speed with a desired shift stage input shaft speed, and selectively performing either a forward control step of increasing a motor torque in a forward direction to increase the motor speed in the forward direction or a negative control step of increasing the motor torque in a negative direction to increase the motor speed in the negative direction. Thus, it is possible to reduce the backward sliding of the vehicle by suppressing the motor speed from unnecessarily increasing and rapidly finishing the downshift.

A method for controlling gear shifting of a hybrid electric vehicle, which is configured for reducing gear-shifting time, minimizing loss by a drive system, improving fuel efficiency and enhancing drivability and which enables a driver to feel a change in acceleration when the driver manipulates the accelerator pedal during power-on upshift active control operation may include speed control of the driving source of the vehicle based on a change rate of a transmission input speed and feedforward control of the clutch of the engagement element in the transmission, to which a driver requested torque is reflected, which are performed at the same time during power-on upshift active control operation, facilitating the driver to feel a change in acceleration which is produced by his or her driving manipulation.

To reduce fuel consumption, a transmission is shifted into a neutral state, called neutral idle, when a vehicle stops in a drive mode. During a transition from a neutral idle state to an engaged state, the engine torque is controlled to avoid excessive shift energy and to mitigate acceleration drop. Specifically, the engine torque is set to a level equal to a sum of a transmission torque capacity and an offset, which is a function of accelerator pedal position. The transmission torque capacity is calculated based on the engaging shift element torque capacity and torque ratios associated with the kinematics and the torque converter. To accommodate noise factors such as variation over time, the offset function is adapted in response to measured clutch energy and acceleration drop.

A method controls a drive system for an axle of a motor vehicle, wherein the drive system has at least an electrical machine as drive unit, a drive shaft which is driven by the drive unit, a first output shaft and a second output shaft and also a first clutch which connects the drive shaft to the first output shaft and a second clutch which connects the drive shaft to the second output shaft.

Disclosed are a parallel start control method and system for a hybrid electric vehicle, and a hybrid electric vehicle. The parallel start control method includes: acquiring current working conditions of a clutch and a gearbox of the hybrid electric vehicle, an engine request torque of the hybrid electric vehicle and a start mode of the hybrid electric vehicle; judging whether the hybrid electric vehicle meets an over-heat protection condition according to the current working conditions of the clutch and the gearbox and determining a start basic torque according to a judging result and the engine request torque; determining a start clutch request torque based on the start basic torque according to the start mode of the hybrid electric vehicle and conducting start control on the clutch according to the start clutch request torque. The start security, responsiveness and power performance of the hybrid electric vehicle are improved.

A hybrid powertrain includes a torque provider, an automatic transmission without a torque converter, and a transfer case configured for providing four wheel drive low range. A controller receives a signal indicative of the transfer case being in low range and determines if brake pedal torque is indicative of a brake pedal being released and, if so, commands engagement of a launch clutch of the transmission up to maximum creep torque capacity at a predetermined maximum gradient. The controller determines when torque provider speed is synchronized with vehicle creep speed, and upon such determination, controls the launch clutch to fully engage to a lock up state to mimic behavior of engagement of a manual transmission gear when the hybrid powertrain is in low range to thereby substantially eliminate a time lag associated with automatic transmissions having a torque converter or a constantly slipping launch clutch.

The present disclosure relates to a shifting control method that improves driving stability by reducing roll-back of a vehicle during the process of shifting on an uphill slope. The shifting control method for a hybrid vehicle includes: determining a degree of roll-back of the vehicle on the basis of a change in the number of revolutions of a transmission input shaft, when power-off down-shifting into a lowest gear is requested; decreasing a disengaging clutch torque, increasing an engaging clutch torque, and increasing a motor torque so that the motor torque follows a desired motor torque, when the degree of roll-back is equal to or greater than a set value; synchronizing a motor speed with an engaging input shaft speed by decreasing the motor torque, when the disengaging clutch torque is equal to or less than a set torque; and finishing the shifting by increasing the motor torque when the synchronization is finished.