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.

An output control system incorporated in a vehicle including a clutch device comprises an upper limit setting section which sets an upper limit value of an output of the drive source to a starting control upper limit value when the output control system is performing a starting control; and a wheelie determiner section which determines whether or not a wheelie is occurring in the vehicle when the output control system is performing the starting control, wherein when the wheelie determiner section determines that the wheelie is occurring, the output control system performs a wheelie suppressing control for suppressing the output of the drive source while maintaining the starting control in such a manner that the output becomes less when the wheelie determiner section determines that the wheelie is occurring than before the wheelie determiner section determines that the wheelie is occurring.

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 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 drive train of a motor vehicle includes the steps: detecting at least one variable; quantifying and/or influencing a movement of the motor vehicle; depending on the variable, switching on an all-wheel drive of the motor vehicle; wherein it is estimated on the basis of the at least one variable whether a relevant driving situation is impending and in this case the all-wheel-drive is switched on before occurrence of the relevant driving situation. A system for operating a drive train of a motor vehicle is also disclosed.

An output control system incorporated in a vehicle including a clutch device comprises an upper limit setting section which sets an upper limit value of an output of the drive source to a starting control upper limit value when the output control system is performing a starting control; and a wheelie determiner section which determines whether or not a wheelie is occurring in the vehicle when the output control system is performing the starting control, wherein when the wheelie determiner section determines that the wheelie is occurring, the output control system performs a wheelie suppressing control for suppressing the output of the drive source while maintaining the starting control in such a manner that the output becomes less when the wheelie determiner section determines that the wheelie is occurring than before the wheelie determiner section determines that the wheelie is occurring.

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

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.