Process and device for adjusting a friction clutch located in a drive train of a vehicle and actuated by an actuator

1 . A process for adjusting a friction clutch located in a drive train of a vehicle and actuated by an actuator, said friction clutch comprising an adjustment device which, on moving an actuation element beyond a displacement range, effects a clutch adjustment compensating for friction lining wear, said process comprising the following steps:

determining whether the drive train of the vehicle is in a state in which an adjustment of the clutch is possible;

determining whether an adjustment of the clutch is necessary;

moving the actuation element beyond the theoretical range so that the adjustment device carries out an adjustment;

activating a slip-control process of the clutch;

determining whether an adjustment has taken place; and, updating the engagement point of the clutch.

2 . The process recited in claim 1 , wherein the friction clutch is pressed into its closed position by the actuation element and the adjustment device is activated by the actuation element being moved beyond a theoretical closed position of the clutch.

3 . The process recited in claim 1 , in which to determine that the vehicle drive train is in a state in which an adjustment of the clutch is possible it must be the case that at least one of the following operating states of the drive train obtains:

suspension of slip control is not critical;

the motor torque is less than a predetermined value;

the rotary speed of the clutch input shaft exceeds a minimum rotary speed;

the gear has been shifted longer than a predetermined period of time;

the slip is less than an upper limit value; or,

no shifting process is activated.

4 . The process recited in claim 1 , where the necessity of an adjustment of the clutch is determined by the period of operation of the clutch.

5 . The process recited in claim 1 , whereby the necessity of an adjustment of the clutch is determined by at least one of the following events:

reduction of the clutch torque which can be transferred during a predetermined actuation of the actuation element;

shift of the engagement point;

reduction of the force to be applied to the actuation element located at a predetermined position; or,

a calculated wear value exceeds a predetermined wear value.

6 . The process recited in claim 1 , where the actuation element is moved beyond the theoretical range according to one of the following control processes:

path control, force control, speed control.

7 . The process recited in claim 1 , where after carrying out an adjustment with a combination of torque control and slip control there is a return to slip control.

8 . The process recited in claim 1 , where it is checked whether an adjustment has taken place by at least one point of an actual characteristic curve for a clutch stored before the activation of an adjustment being compared to one point of a characteristic curve present after the adjustment.

9 . The process recited in claim 8 , where the actual characteristic curve is adapted according to the deviation.

10 . A device for adjusting a friction clutch located in a drive train of a vehicle, actuated by an actuator, and comprising an adjustment device which, on moving an actuation element beyond a displacement range, effects a clutch adjustment compensating for friction lining wear, comprising the actuator ( 14 ) for actuating the actuation element ( 16 ), sensors for determining the clutch slip, the torque transferred by the clutch ( 10 ), and the position of the actuation element and an electronic control device ( 32 ) for controlling the actuator as a function of clutch slip, of clutch torque, and in given cases of additional operational parameters of the drive train, said control device comprising at least one characteristic curve for a clutch, said characteristic curve including the torque transferable by the clutch as a function of the position of the actuation element and being operatively arranged for carrying out a process for adjusting the friction clutch, said process comprising the following steps:

determining whether the drive train of the vehicle is in a state in which an adjustment of the clutch is possible;

determining whether an adjustment of the clutch is necessary;

moving the actuation element beyond the theoretical range so that the adjustment device carries out an adjustment;

activating a slip-control process of the clutch;

determining whether an adjustment has taken place; and,

updating the engagement point of the clutch.

11 . The device recited in claim 10 , where the clutch is a clutch comprised in a parallel shift gearbox.