The invention relates to a powertrain for a motor vehicle having a permanently driven primary axle, comprising: a drive unit for the generation of a drive torque; a first clutch for the transfer of a variable portion of the drive torque to a secondary axle of the motor vehicle; a second clutch for the deactuation of a torque transfer section of the powertrain arranged between the first clutch and the second clutch when the first clutch is opened; and a control unit for the automatic control of the first clutch, with the control unit being connected to at least one sensor for the detection of a wheel slip at the primary axle; with the control unit being made, starting from a deactuated state of the torque transfer section, to close the second clutch in dependence on a detected wheel slip at the primary axle.

A system and method of controlling engine clutch engagement during TCS operation of a hybrid vehicle are provided. The method includes determining whether a TCS is operating and upon determining that the TCS is operating, determining a compensation value for early engagement of an engine clutch during the TCS operation based on a difference between a front wheel speed and a rear wheel speed and a slip amount of front wheels. Additionally, the method includes determining whether engagement of the engine clutch is capable of being started based on the compensation value and starting the engine clutch engagement. Since the engagement of the engine clutch is controlled based on the speed of non-drive wheels during TCS operation, the engagement stability of the engine clutch is improved and the amount of time required to engage the engine clutch is decreased.

A mechanical front wheel drive roller wedging control system includes a 4WD switch in a vehicle operator station, a roller cage drag mechanism electrically activated by the 4WD switch and providing a drag on a roller cage if the 4WD switch is in an on position, and a throttle pedal switch actuated by the throttle pedal and that deactivates the roller cage drag mechanism when the throttle pedal is released.

A method of controlling a selectable one way clutch operable to selectively couple a shaft to a housing of a transmission includes determining if an electric motor is currently operating, and if the selectable one way clutch is currently engaged to couple the shaft to the housing. It is further determined whether or not wheel torque of at least one wheel is currently being actively managed by at least one vehicle control system. When the electric motor is operating with the selectable one way clutch engaged, and wheel torque of at least one wheel of the hybrid vehicle is currently being actively managed by at least one vehicle control system, then selectable one way clutch is disengaged to release the shaft from the housing and allow rotation of the shaft relative to the housing.

A four-wheel drive vehicle are provided which enable enhancement of responsiveness to switching from a two-wheel drive state to a four-wheel drive state. A four-wheel drive vehicle includes a driving force transmission and cut-off apparatus that enables cut-off of transmission of a driving force from an engine to a propeller shaft, a driving shaft that rotates under a tuning force of the propeller shaft, a pair of hydraulic clutches and each disposed between the driving shaft and a corresponding one of rear wheels, and a control apparatus that controls a hydraulic unit that supplies hydraulic oil to the hydraulic clutches. In shifting the two-wheel drive state to the four-wheel drive state, the control apparatus controls the hydraulic unit such that a higher priority is given to supply of the hydraulic oil to first hydraulic clutch than to supply of the hydraulic oil to second hydraulic clutch.

A method for operating a drivetrain for a motor vehicle, said method includes: reducing a transmission torque transmitted between a primary drive axle operatively connected with a secondary drive axle of the motor vehicle via a clutch configured to allow adjustment of the transmission torque when determining at the secondary drive axle a wheel slip which exceeds a defined slip threshold value

A clutch control system mitigates driveline shock loads in a vehicle. The clutch control system has 1) A friction clutch capable of transitioning between a fully open, a partially open, and a fully closed position; 2) A control unit configured to receive vehicle data, wherein the vehicle data comprises current engine torque, and define one or more operational modes of the friction clutch, wherein the one or more operational modes comprise a driveline protection mode defined by having an operating range between the fully open position and an effectively closed position of the clutch, wherein the effectively closed position is a partially open position having a torque capacity that exceeds the current engine torque, thereby preventing clutch slip at the effectively closed position; and 3) A clutch actuator configured to operate the clutch in accordance with the one or more operational modes, including the driveline protection mode.

Embodiments relating to a method for a vehicle comprising two clutches connected to rear wheels of the vehicle and arranged to transmit torque to the rear wheels of the vehicle, the two clutches being connected to a propulsion actuator, the operating method comprising detecting an oversteering situation based on first data indicative of a vehicle motion state, detecting that a propulsion torque generated by the propulsion actuator is above a first threshold based on second data indicative of the propulsion torque generated by the propulsion actuator, and adjusting a torque request to the two clutches, wherein the two clutches are arranged to transmit torque to the rear wheels based on the torque request and based on the propulsion torque generated by the propulsion actuator.

A method for controlling a starting process of a vehicle includes activating a control sequence and setting a control sequence signal, defining a maximum engine drive torque, and detecting a drive request for a starting process. The method further includes, in response to the drive request, controlling a clutch-gearbox unit with an engagement process duration, controlling wheel slip of driven wheels by determining wheel speeds of the driven wheels and at least setting an output drive torque at the output shaft, and redefining the maximum engine drive torque depending on the wheel slip and a driving speed. The method also includes deactivating the control sequence and resetting the control sequence signal when limit values are reached.