Patent ID: 7873457

Claim:
A method of controlling torque transfer in an all-wheel drive vehicle having a powertrain, first and second drivelines, a clutch for controlling the distribution of torque to the first and second drivelines, sensors for determining the wheel speeds for both drivelines, a control unit for calculating a new command torque value, and a clutch actuator energized by the control unit for engaging the clutch to generate the new command torque, said method comprising the steps of: calculating a speed difference value based on the wheel speeds detected by the sensors; comparing the speed difference value to a threshold value; integrating the deviation between the speed difference value and the threshold value once the speed difference exceeds the threshold value; continue integration of the deviation until the integral reaches a limit value which is a function of the last command torque value; calculating the new command torque value once the integral reaches or exceeds the limit value as a function of the last command torque and a gradient value of the speed difference; and outputting a control signal to the clutch actuator corresponding to the new command clutch for engaging the clutch.