Clutch contact points

1. A method for controlling a twin clutch transmission including at least two partial drive trains, each of which is coupleable to a combustion engine using a respective clutch (K 1 , K 2 ), comprising the following steps to be carried out on the inactive partial drive train:

shifting from an engaged gear to neutral with the clutch of the inactive partial drive train open;

determining the drag torque M S of the input shaft of the inactive partial drive train during a predetermined period P 1 ( 130 );

closing the clutch of the inactive partial drive train up to a predetermined position in which a clutch torque is transmitted and determining a total torque M of the input shaft of the inactive partial drive train during a predetermined period P 2 ( 140 );

determining the clutch torque M K of the input shaft of the inactive partial drive train from the drag torque M S and the total torque M as the sum of the drag torque M S and the clutch torque M K ; and

determining a contact point position from the absolute value of the determined clutch torque M K and a clutch characteristic of the clutch of the inactive partial drive train.

2. The method recited in claim 1 , wherein the predetermined position is a position of the clutch of the inactive partial drive train that is between the open position of the clutch of the inactive partial drive train and the contact point position determined before period P 1 .

3. The method recited in claim 1 , wherein the predetermined position is a position of the clutch of the inactive partial drive train that is between the open position of the clutch of the inactive partial drive train and the contact point position determined before period P 1 plus an offset.

4. The method recited in claim 3 , wherein the offset is between 0 and 5 millimeters.

5. The method recited in claim 1 , wherein the drag torque M S is determined in accordance with the equation

M

S

=

Θ

EW

⁢

⁢

1

⁢

π

30

⁢

n

.

1

,

with Θ EW1 the moment of mass inertia of the inactive input shaft of the inactive partial drive train and n 1 the speed of the inactive input shaft of the inactive partial drive train.

6. The method recited in claim 1 , wherein the total torque M is determined in accordance with the equation

M

=

Θ

EW

⁢

⁢

1

⁢

π

30

⁢

n

.

1

,

with Θ EW1 the moment of mass inertia of the inactive input shaft of the inactive partial drive train and n 1 the speed of the inactive input shaft of the inactive partial drive train.

7. A device for controlling a twin clutch transmission including at least two partial drive trains, each of which is coupleable to a combustion engine by means of a clutch (K 1 , K 2 ), wherein a method as recited in claim 1 is carried out on the inactive partial drive train.

8. A method for controlling a twin clutch transmission including at least two partial drive trains, each of which is coupleable to a combustion engine using a respective clutch (K 1 , K 2 ), comprising the following steps to be carried out on the inactive partial drive train:

shifting from an engaged gear to a neutral gear ( 100 ) with the clutch of the inactive partial drive train open;

determining the drag torque M S of the input shaft of the inactive partial drive train during a predetermined period P 1 ( 130 );

closing the clutch of the inactive partial drive train up to a predetermined position in which a clutch torque is transmitted and determining a total torque M of the input shaft of the inactive partial drive train during a predetermined period P 2 ( 140 );

determining the clutch torque M K of the input shaft of the inactive partial drive train from the drag torque M S and the total torque M as the sum of the drag torque M S and the clutch torque M K ; and

determining a contact point position from the absolute value of the determined clutch torque M K and a clutch characteristic of the clutch of the inactive partial drive train, wherein the periods P 1 and P 2 are selected in a way that their sum is shorter than the period in which the neutral gear is engaged.

9. A method for controlling a twin clutch transmission including at least two partial drive trains, each of which is coupleable to a combustion engine using a respective clutch (K 1 , K 2 ), comprising the following steps to be carried out on the inactive partial drive train:

shifting from an engaged gear to neutral with the clutch of the inactive partial drive train open;

determining the drag torque M S of the input shaft of the inactive partial drive train during a predetermined period P 1 ( 130 );

closing the clutch of the inactive partial drive train up to a predetermined position in which a clutch torque is transmitted and determining a total torque M of the input shaft of the inactive partial drive train during a predetermined period P 2 ( 140 );

determining the clutch torque M K of the input shaft of the inactive partial drive train from the drag torque M S and the total torque M as the sum of the drag torque M S and the clutch torque M K ; and

determining a contact point position from the absolute value of the determined clutch torque M K and a clutch characteristic of the clutch of the inactive partial drive train, wherein the clutch of the inactive partial drive train is subsequently opened and a gear is engaged in the inactive partial drive train, the gear being the same as or different from the gear from which a shift to neutral occurred with the clutch open.