DE4134669C2 - Arrangement for detecting the position of starting torque transmission of a motor vehicle clutch - Google Patents

Description

The invention relates to an arrangement for detecting the position starting Torque transmission (limit position) of an actuatable by an actuator, in Driving force path between an engine and a transmission of a motor vehicle orderly friction clutch.

It is known to egg in the driving force path between an engine and a transmission Nes motor vehicle arranged, operated by an actuator friction clutch both when starting the motor vehicle and when changing gears of a controller automatically disengage or engage. During the movement in off coupling direction is comparatively unproblematic, provided that it takes place quickly enough for a clutch-friendly and jerk-free engaging to ensure that the Coupling, based on the disengaged, no torque transmitting Position is quickly transferred to a so-called limit position in which the clutch is just starting to transmit torque to subsequently correspond to the driving si tuation moved more or less slowly to the fully engaged position will. For the movement between the limit position and the fully engaged  position, a number of clutch control strategies have been developed which Grinding area, d. H. in the event of a slipping clutch, as gently and jerk-free as possible allow it to engage. Examples of such engagement strategies are described in DE-A-39 35 438 and DE-A-39 35 439.

The conventional engagement strategies assume that the current limit position, in which the clutch begins according to its current operating situation To transmit torque is known exactly. If the from the disengaging position Limit position leading rapid coupling movement into the grinding area leads, this manifests itself as an undesirable jerk. However, the rapid movement Ended too early, so there is dead time within which the engine starts, for example ren already accelerated to undesirably high speeds while the clutch transmits no or too little torque. This also reduces driving comfort and causes increased clutch wear.

From DE-A-40 11 850 and EP-A-392 762 it is used to determine the current Limit position known, with the vehicle stationary and neutral gear position of the gearbox the clutch to determine the limit position from the disengaged Position over the limit position in the fully engaged position control and then open again. The motor monitored during this movement speed changes as torque transmission begins, which is an indicator of the limit position detected by means of a clutch position sensor is used. A disadvantage of the known limit detection methods is that they are special Require operating situations that may only occur in normal driving rarely occur. On the other hand, the limit position of the clutch does not only change depending on the wear-related long-term behavior of the clutch, but also from depending on the currently changing operating parameters, especially the clutch lung temperature. It is therefore desirable that the limit position of the clutch is updated as often as possible, but only with the known investigation methods is insufficiently realized.

A similar limit position determination method is known from DE-C-32 18 933, at which however not the engine speed, but the transmission input speed for the Determination of the limit position is evaluated. With this method, the transfer  a certain torque is allowed to reduce the frictional effects of the clutch, which can lead to a falsification of the limit position measurement. But also with this method the limit position of the clutch is in neutral gear position and stationary motor vehicle determined so that the above parts result.

From British patent application 2 170 571 is a device for actuating a Friction clutch known in which stored data for the start of the Torque transmission are monitored, for example, the actuation pressure is used for clutch actuation. Here, based on changes changes in the actuation pressure to the wear condition of the clutch will.

Furthermore, it is known from the German patent application 38 00 607, in the area to arrange the clutch a temperature sensor which with the clutch actuation in Connection is established and the switching operations of a certain limit temperature Coupling prevented.

It is an object of the invention to begin an arrangement for detecting the position Torque transmission (limit position) of an automatically operated friction clutch ment of a motor vehicle to specify the one hand, an exact determination of the limit position allowed and on the other hand frequent updating of the stored value the limit position.

The invention is based on an arrangement with a detected the speed of the engine send engine speed sensor, a clutch that detects the position of the clutch Position sensor, means that detect a starting mode of the motor vehicle, one the drive movement of the actuator of the clutch at least in the start-up mode Art automatically transmits no torque across the limit position the, disengaged position in a torque-transmitting, at least partially se coupled position controlling control, a data storage for storage clutch control data, including data indicating a current limit position of the Represent coupling and means for correcting the current limit position data depending on the engine speed detected by the engine speed sensor.  

Based on such an arrangement, the above object is fiction solved according to that the limit position data correction means the size of the maxi mums one that occurs when the clutch is closed during start-up Detect engine speed overshoot and save them in the data memory Limit position data depending on the size of the maximum engine speed Correct overshoot.

The invention is based on the knowledge that when starting the motor vehicle the engine usually accelerates faster than the clutch for transmission supply of the torque generated by the engine closes. There is a short one early increase in engine speed in the form of an engine speed overshoot, before the clutch has closed so far that it brakes the motor again. It has been shown that the size of the maximum of this engine speed overshoot is a measure of the current limit position of the clutch and to update the ge stored limit value can be used. The maximum of the engine speed overshoot is greater, the more time the motor has due to Ab deviations of the stored limit value from the actual limit position remains for the acceleration. The correction of the stored limit position data can be carried out comparatively often because it is during start-up of the motor vehicle, i.e. during a comparatively frequent operating situation, is carried out.

The assignment of the maximum size of the engine speed overshoot to the current one The limit is set empirically. The less operating temperature to be taken into account the easier and more accurate it is to store the stored limit position data correct. In a particularly simple embodiment of the invention provided that the means detecting the starting operation a the setting of a Accelerator pedal of the motor vehicle detecting accelerator pedal sensor have and in the start-up mode an essentially constant time setting acceleration pedal, and that the limit position data Correction means the limit position data only with a substantially constant setting Correct the accelerator pedal. This way at least one of the Motor parameters kept constant. This parameter is, for example the torque generated by the motor according to the pedal position, or else it  is the motor speed kon for a motor with setpoint-controlled speed control kept constant.

Keeping the motor parameter constant is easier, the lower that of Engine generated engine torque or the lower the engine speed. Purpose moderately it is ensured by monitoring suitable parameters that the ge saved current limit position data only when starting slowly or when Shunting be corrected. This can be achieved in a very simple way by that the limit position data correcting means only then the limit position data correct if the accelerator pedal is less than a predetermined fraction, in particular less than 40% of its maximum out steering position, is deflected.

To the current, stored limit position data depending on the respectively recorded To be able to correct the size of the maximum of the engine speed overshoot is in a preferred embodiment of the invention provides that the limit position ten correction means comprise a characteristic curve memory, the predetermined limit position data as a function of the size of the maximum of the engine speed overshoot saves and the current limit position data depending on the recorded size of the Selects maximums. The characteristic curve memory stores at least one empirically telte characteristic, but preferably several for different operating parameters of the Motors determined characteristic curves, for example in the form of tables, for updating the limit position data are evaluated.

The empirically determined, predetermined, stored in the characteristic curve memory Limit position data is expediently a function of the size one on one Reference speed-related maximum of the engine speed overswing chert. The reference speed can be, for example, the idling speed of the Act motors or the accelerator already mentioned above Accelerator pedal position dependent target engine speed.

While in the embodiment of the invention explained above, a predetermined one Relationship between the size of the maximum of the engine speed overshoot and the limit position exists, the limit position data correction means regulate the  The embodiment of the invention explained below shows the current limit position data automatically to a correct value. In this embodiment, the controller controls the actuator at least in the area of torque-transmitting positions from the saved current limit position data. The limit position data correction Turmittel compare here the size of the maximum of the engine speed overshoot gers with the value of a predetermined reference speed and correct the in the data memory stored limit position data in particular step by step for correction increments so that the size of the maximum adjusts itself to a value that in the we is substantially equal to the reference speed value. The reference speed value becomes empi It determines and sets the value to which the engine speed when starting in the correctly set limit position. Among the above The reference speed is suitable for conditions of starting parameters that are as constant as possible moderately depending on the current idling speed and / or depending on the setpoint which is set when the vehicle is started up in accordance with the accelerator pedal Engine speed.

An embodiment that is particularly suitable for the latter variant is that is characterized in that the means detecting the starting operation one the one position of the accelerator pedal of the motor vehicle detecting acceleration have pedal sensor, and that the limit position data correction means a characteristic include memory, the predetermined reference speed data as a function of on position of the accelerator pedal and the current limit position data depending on the current assigned to the detected accelerator pedal position Corrected reference speed data. An embodiment of this type allows particularly exact correcting the limit position data, especially when the characteristic curve saves data which, as already mentioned, represent target engine speeds and the control comprises engine speed control means, the engine speed at least during part of the starting operation on the accelerator pedal detected by the position set certain current target engine speed so that the limit position da correction means the current limit position data depending on the current target Can correct engine speed. The reference speed can be the target Act engine speed; however, the reference speed value can also be increased by one empi risch determined, predetermined value to be increased compared to the target engine speed.  

Motor vehicles are usually used when the outside temperature fluctuates greatly drove. While temperatures can be as low as -20 ° C in winter, can rise to 40 ° C and more in summer. Although the middle operation temperature fluctuates far less and in the order of magnitude between 70 and 90 ° C, the operating temperature can temporarily if the clutch is overloaded also rise to much higher values, for example 150 ° C and more. Nevertheless, this is said to range from a cold start in winter to overheating stood in the summer temperature range a flawless automatic Coupling operation are made possible. The invention is therefore under another Aspect of the task in a very wide temperature range for a jerk Free and clutch-friendly mode of operation of an automatically operated friction clutch to ensure the driving force path between an engine and a transmission be a motor vehicle is arranged.

In this aspect of the invention it is proposed that the limit position Correction means a temperature detecting the temperature in the area of the clutch have sensor and the stored, current limit position data only then correct during a drive movement leading over the limit position, if the detected temperature is less than a predetermined upper limit temperature. This Aspect is based on the knowledge that it is more favorable for clutch comfort, outside the specified temperature limits of the ambient temperature of the coupling to waive the determination of the current limit position data or the correction the limit position data according to principles other than the measurement of the limit position to carry out, because outside of these temperature limits the properties of the components involved in the position measurement can change significantly. Here will expediently not only takes into account a predetermined upper limit temperature, but also a predetermined lower limit temperature, the limit position Correction means only then during the stored current limit position data the drive movement of the actuator corrected via the limit position, if the detected temperature is greater than the specified lower limit temperature.

To be outside the range between the upper and lower limit temperature It is possible to correct the saved current limit position data in one preferred embodiment provided that the limit position correction means the ge  correct the current limit position data by one position increment proportional to the temperature difference of a given average operating temperature is in the area of the clutch minus the sensed temperature when the sensed tempera tur above the upper limit temperature or below the lower limit temperature lies. This configuration takes into account that the ambient temperature of the Clutch both for a cold start in winter and for a momentary over heating of the clutch will return to the mean operating temperature in the foreseeable future same, which lies between the upper and the lower limit temperature. The ak Current limit position data is thus temperature-dependent in the direction of the for mean operating temperature applicable value, with a suitable choice of Proportionality constant jumps in the limit position data at the transition between the normal correction method and the temperature-dependent correction method largely avoided. The temperature sensor expediently measures that Air temperature in a bell housing enclosing the clutch, for example of the transmission.  

In the following the invention with reference to drawings explained in more detail. Here shows:

Figure 1 is a schematic block diagram of an arrangement for actuating a friction clutch of a motor vehicle.

Fig. 2 to 4 diagrams for explaining the vorese hen in the arrangement of FIG. 1 according to the invention means for detecting and correcting a limit position of the clutch and

Fig. 5 is a flow chart for explaining a preferred embodiment of the invention.

Fig. 1 shows a between a motor 1 and a gearbox 3 of a motor vehicle arranged Reibungskupp treatment 5 , which is adjustable by means of a positioning drive 7 on a determined by a position control signal Ausrückerposi tion. A clutch position sensor 9 detects the actual position of the positioning drive 7 acting as a position control circuit. A clutch control 11 , which is preferably a microprocessor or the like, supplies, depending on the driving situation of the motor vehicle, target data for the position control signal both when starting off and when changing the gears of the transmission 3 . Clutch control data required for this are stored in a data memory 13 . The power of the engine 1 is set on a driving or accelerating pedal 15 , the position α of which is detected by a pedal position sensor 17 . The controller 11 , which is connected to the pedal position sensor 17 , controls a drive mechanism 19 of a power actuator 21 of the engine 1 , for example its throttle valve or injection pump, in driving operation depending on the detected pedal position.

For the starting of the vehicle, the clutch 5 is positioned by the speed control means of the controller 11, by means of a speed sensor 23, the actual speed of the motor 1 can detect and Len the positioning drive 7 so stel that the error between the detected by the sensor 23 the actual engine speed and a target engine speed n _s disappears. The target engine speed n _s is determined by a characteristic curve stored in the data memory 13 as a function of the accelerator pedal position α. Fig. 4 shows an example of such a characteristic, which specifies a target value of the engine speed when starting the motor vehicle or when maneuvering and controls the positioning drive 7 so that the engine speed is maintained at the target engine speed predetermined by the current accelerator pedal position while the clutch 5 is adjusted from its non-torque-transmitting disengaged position to a limit position in which it begins to transmit torque to its torque-transmitting engaged position. Details of the method used for starting are described in DE-A-39 35 439, to which reference is made here. Another method can be provided for changing gears, as described for example in DE-A-39 35 438. In this method, the transmission input speed is additionally detected by means of a speed sensor 25 and the slip of the clutch 5 is reduced as a function of time according to a predetermined characteristic curve when changing gear. The transmission 3 comprises gear position sensors connected to the controller 11 and optionally further sensors, such as vehicle speed sensors, which enable the controller 11 to distinguish between a start-up mode and gear change modes.

When engaging the clutch 5 , the positioning drive 7 drives the clutch 5 first quickly to the limit position starting torque transmission, in order to then engage the clutch according to the starting mode or the gear change mode. The limit position data are stored in the data memory 13 and must be updated if jerk-free and gentle operation of the clutch 5 is to be achieved. The limit position data change not only with increasing wear of the clutch 5 , but also depending on the operating situation of the clutch, in particular its temperature. Since the operating temperature of the clutch 5 can change comparatively quickly, a frequent update of the limit position data is desirable. In the context of the invention, this is achieved by monitoring a speed overshoot that occurs during slow starting or in maneuvering operation, as will be explained below with reference to FIGS .

FIG. 2 shows the accelerator pedal position α over time t for a slow starting process or for maneuvering operation, at which time t ₀ begins to deflect the accelerator pedal 15 from its rest position until it reaches a maximum value α _m at time t ₁ which is then held for the following maneuvering or starting process. The position α _m is smaller than a predetermined limit value α ₀ , which in turn is considerably smaller than the full-load deflection of the accelerator pedal 15 . The limit value α ₀ is expediently chosen to be smaller than approximately 40% of the maximum possible deflection of the acceleration pedal 15 and is usually between approximately 15% and approximately 25% depending on the motor vehicle.

Depending on the current position α of Accelerati supply pedals 15, the controller 11 outputs corresponding to in Fig. 4 shown, stored in the data memory 13 characteristic of a target engine speed n _s in front of which only small due to the by α ₀ limited deflection of the accelerator pedal 15 in is close to the idle speed n _{0 of} the engine 1 and changes according to the position of the accelerator pedal. Fig. 3 shows dashed lines the time course of the target engine speed n _s for the accelerator pedal position changing according to FIG. 2.

Fig. 3 shows with a solid line the course of the engine speed n _m measured by the sensor 23 and with a dash-dotted line the course of the transmission input speed n _g . The engine reacts to the increase in the target engine speed n _s in the period t ₀ to t ₁ with a slight delay with an increase in the engine speed n _m . Due to the resulting deviation of the engine speed n _m from the target engine speed n _s , the controller 11 begins to engage the clutch 5 via the positioning drive 7 .

Since the torque transmitted by the clutch builds up more slowly than the torque generated by the engine 1 during the engagement process, there is a brief overshoot Δn of the engine speed n _m beyond the target engine speed n _s before the engine 1 through the closing Clutch 5 is braked and the gearbox input speed n _{g adapts to} the engine speed n _m . The size of the maximum of the overshoot Δn is a measure of the limit position. in which the clutch begins to transmit torque. The limit position, the data of which are stored in the data memory 13 , determine that position of the clutch 5 at which the control 11 switches the positioning drive 7 from the rapid approach operation to the smooth closing of the clutch 5 in its slip area. If the stored current limit position is set too far in the coupling direction, the clutch is guided too quickly into the torque-transmitting area, so that there is a Einkup pelruck, with the result that the engine speed overshoot reaches only a small size. On the other hand, the stored current limit position is too strongly offset in the disengaging direction, the control 11 slows down the delivery rate of the clutch before the limit position is actually reached, with the result that the motor 1 can accelerate more in the meantime, which is called increased engine speed overshoot.

The correction of the current limit position data used by the controller 11 for engaging the clutch and stored in the data memory 13 can be carried out, for example, on the basis of an empirically determined characteristic field which is also stored in the data memory 13 and which shows the value of the limit position as a function of the size of the Engine speed overshoot Δn represents. This can be a single characteristic curve or a family of characteristic curves which take into account further parameters, in particular the target engine speed n _s .

Alternatively, the stored current limit data can also be corrected step by step using the control method explained below with reference to FIG. 5. This control method takes into account the temperature dependency of empirically determined values and characteristics and enables the clutch 5 to be controlled smoothly and gently even in a large operating temperature range using correctly determined limit position data. This point of view can also be used in the variant of the characteristic curve-dependent correction of the stored limit position data explained above, as well as in other, in particular, conventional limit position correction arrangements.

For the consideration of the operating temperature of the clutch 5 position data in the identification and correction of the limit, the clutch measures a temperature sensor 27, the temperature indicated structure of the ambient air of the clutch 5 in a at 29, 5 protectively surrounding clutch housing. The correction means of the controller 11 respond to the temperature sensor 27 and only allow the stored current limit position data to be corrected on the basis of the engine speed overshoot if the bell air temperature is less than an upper limit temperature and greater than a lower limit temperature. The limit temperatures are dimensioned such that they enclose the mean bell air temperature occurring during operation and allow the corrective means to work properly on the basis of empirically determined data. For an average bell air temperature of, for example, 70 to 80 °, the upper limit temperature is approximately 120 °, while the lower limit temperature is selected at approximately 40 ° C.

Outside the temperature range between lower and upper limit temperature can in individual cases to a cor correction of the limit position data can be dispensed with if until operational adjustment of the bell air temperature temperature at the range of the mean bell air temperature a reduction in comfort is accepted. The comfort however, mitigation can be significantly reduced if outside the temperature range between lower and upper limit temperature the limit position data each because corrected by correcting the correcting values be proportional to the difference between the average bell air temperature minus the current are measured bell air temperature. The proportion This factor is determined empirically. For example, the average bell air temperature 70 ° and the current temperature 150 °, see above  results with a proportionality factor of to Example 8 a correction value of minus 10 by which the currently saved limit position data reduced will. The sign of the correction value is chosen so that if the temperature falls below the lower limit corrected the limit position data in the engagement direction and if the upper limit is exceeded temperature in the disengaging direction.

Step 31 of the flowchart according to FIG. 5 denotes a distribution program of the control 11 , with which the limit position correction routine is periodically repeated. In step 33 , a query is made as to whether the bells air temperature measured by means of the temperature sensor 27 is within the abovementioned temperature limits. If the bell air temperature is outside, the program is exited via the NO branch. The program jumps to step 35 "End" and, if necessary, leads back to distribution step 31 . If the bell air temperature lies between the upper and the lower limit temperature, a query is made in step 37 as to whether a gear suitable for starting is engaged on the transmission 3 . If no, the program is exited via end step 35 ; if so, step 39 checks whether the vehicle brake, in particular the hand brake, is released. If no, the correction program is terminated, if yes, a check is carried out in a step 41 to determine whether a predetermined time span of 1 to 2 seconds has been exceeded since the start of the program. This step makes it possible to recognize whether the clutch is already in a grinding area in which the vehicle is held on a slope with a sliding clutch, for example. If step 41 is answered in the negative, the program is terminated; if the answer is affirmative, it is checked in step 43 whether the accelerator pedal 15 is deflected from its rest position, but is in a position smaller than the limit position α ₀ . If the limit position α _{0 is} exceeded, the correction program is terminated; If the limit position α ₀ has not yet been reached, a step 45 checks whether the position α of the accelerator pedal 15 is still changing. If the position of the accelerator pedal 15 is not constant, the correction program is terminated; if it is constant, the value α _{m is} determined in a step 47 , which the position of the accelerator pedal 15 has reached as a maximum. In a step 49 it is checked again whether the maximum position α _{m of} the acceleration pedal 15 determined in this way has remained below the limit position α ₀ . If α _m exceeds the limit position α ₀ , the correction program is terminated; otherwise it is checked in a step 51 whether the maximum position α _m remains constant. If it does not remain constant, the correction program is canceled; If it remains constant, the engine speed at the maximum of the engine speed overshoot is determined in a step 53 . In a subsequent step 55 , this maximum engine speed is compared with the target engine speed n _s corresponding to the characteristic curve from FIG. 4 for the maximum accelerator pedal position α _m and the difference Δn between the maximum engine speed overshoot and the target -Motor speed determined. In a step 57 , the value Δn is compared with an empirically determined, predetermined threshold and, depending on the comparison, the current value of the limit position of the clutch 5 stored in the data memory 13 is increased or decreased by a predetermined increment. If Δn is greater than the threshold, the limit position is changed by the increment in the coupling direction; If Δn is less than the threshold, the limit position in the disengaging direction is corrected by the increment. After step 57 , the correction program is ended via the end step 35 to the distribution step 31 .

Claims (13)

1. An arrangement for detecting the position of starting torque transmission (limit position) of a stall drive ( 7 ) which can be actuated and is arranged in the driving force path between an engine ( 1 ) and a transmission ( 3 ) of a motor vehicle arranged friction clutch ( 5 ), comprising:

• 1. - a motor speed sensor ( 23 ) detecting the speed of the motor ( 1 );
• 2. - a clutch position sensor ( 9 ) detecting the position of the clutch ( 5 );
• 3. - means ( 17 , 49 , 51 ) which detect a starting mode of the motor vehicle;
• 4. - The drive movement of the actuator of the clutch at least in the driving mode automatically beyond the limit position from a torque-transmitting, disengaged position into a torque-transmitting, at least partially engaged position controlling control;
• 5. - A data memory ( 13 ) for storing clutch control data, including data representing a current limit position of the clutch ( 5 ) and
• 6. means for correcting the current limit position data as a function of the engine speed detected by the engine speed sensor ( 23 ),

characterized in that the limit position data correction means detect the size of the maximum of an engine overspeed overshoot occurring when the clutch ( 5 ) is engaged during starting operation and correct the limit position data stored in the data memory ( 13 ) depending on the size of the maximum of the engine speed overshoot . 2. Arrangement according to claim 1, characterized in that the starting mode detecting means ( 17 , 49 , 51 ) have an accelerator pedal ( 15 ) of the motor vehicle detecting the accelerator pedal sensor ( 17 ) and in the starting mode a temporally substantially constant setting of the accelerator pedal ( 15 ), and that the limit position data correcting means correct the limit position data only when the accelerator pedal ( 15 ) is set substantially constant. 3. Arrangement according to claim 2, characterized in that the limit position data correction means correct the limit position data only when the accelerator pedal ( 15 ) is deflected in the starting mode by less than a predetermined fraction, in particular less than 40%, of its maximum deflection position. 4. Arrangement according to claim 1, characterized in that the limit position data correction means comprise a characteristic curve memory ( 13 ), which stores predetermined limit position data as a function of the size of the maximum of the engine speed overshoot and selects the current limit position data depending on the detected size of the maximum. 5. Arrangement according to claim 4, characterized in that the limit position data correction means store the predetermined limit position data as a function of the size of a reference speed (n _s ) related maximum of the motor speed overshoot. 6. Arrangement according to one of claims 1 to 3, characterized in that the controller ( 11 ) controls the actuator ( 7 ) at least in the area of torque-transmitting positions depending on the stored, current limit position data, and that the limit position data correction means the size of the Compare the maximum of the engine speed overshoot with the value of a predetermined reference speed and correct the limit position data stored in the data memory ( 13 ) in particular step by step so that the size of the maximum adjusts to a value that is essentially the same as the reference speed. 7. Arrangement according to claim 5 or 6, characterized in that the starting operation detecting means ( 13 , 49 , 51 ) have a setting of an accelerator pedal of the motor vehicle detecting accelerator pedal sensor ( 17 ), and that the limit position data correction means a Kennli nienspeicher ( 13 ), which stores predetermined reference speed data (n _s ) as a function of the setting of the accelerator pedal and corrects the current limit position data as a function of the current reference speed data assigned to the detected accelerator pedal setting. 8. Arrangement according to claim 7, characterized in that the characteristic curve memory stores data representing the target engine speed (n _s ), that the controller ( 11 ) comprises engine speed control means which the engine speed at least during part of the starting operation on the determined by the accelerator pedal position he determined current target engine speed, and that the limit position data correcting means correct the current limit position data depending on the current target engine speed. 9. Arrangement according to claim 8 in connection with claim 6, characterized, that the reference speed value is equal to that increased by a predetermined value Target engine speed is selected. 10. Arrangement according to claim 1 for detecting the position of torque transmission (limit position) of an actuator ( 7 ) operable in the driving force path between a motor ( 1 ) and a transmission ( 3 ) of a motor vehicle arranged friction clutch ( 5 ), comprising

• 1. - a clutch position sensor ( 9 ) detecting the position of the clutch;
• 2. - The drive movement of the actuator ( 7 ) of the clutch ( 5 ) automatically over the limit position between a no torque-transmitting position and a torque-transmitting, at least partially engaged position controlling control ( 11 );
• 3. - a data memory ( 13 ) for storing clutch control data, including data representing a current limit position of the clutch; and
• 4. means which deliver information data representing the limit position during the drive movement of the actuator leading over the limit position and accordingly correct the current limit position data stored in the data memory ( 13 ),

characterized in that the limit position correction means have a temperature sensor in the area of the coupling ( 27 ) and correct the stored current limit position data only during the drive movement leading over the limit position if the detected temperature is lower than a predetermined upper limit temperature . 11. The arrangement according to claim 10, characterized in that the limit position correction means correct the stored current limit position data only during the movement of the actuator ( 7 ) leading over the limit position when the detected temperature is greater than a predetermined lower limit temperature. 12. The arrangement according to claim 10 or 11, characterized in that the limit position correction means correct the stored current limit position data by an increment which is proportional to the temperature difference of a predetermined average operating temperature in the region of the clutch ( 5 ) minus the detected temperature, if the detected temperature is above the upper limit temperature or below the lower limit temperature. 13. Arrangement according to one of claims 10 to 12, characterized in that the temperature sensor ( 27 ) measures the air temperature in a coupling ( 5 ) around the closing bell ( 29 ).