DE102017119105A1 - Method for adjusting a torque characteristic of a clutch actuation system, preferably a vehicle - Google Patents

Abstract

The invention relates to a method for adapting a torque characteristic of a clutch actuation system, preferably of a motor vehicle, in which a nominal torque characteristic, which indicates a transmissible clutch torque as a function of an actuator position, is adapted to a clutch-specific torque characteristic by a friction value adaptation. In a method in which the accuracy of the clutch system-specific torque characteristic to be determined is increased, during the friction value adaptation, the nominal characteristic is shifted via an actuator travel at a constant torque level, whereby the clutch-specific torque characteristic is determined.

Description

The invention relates to a method for adapting a torque characteristic of a clutch actuation system, preferably a vehicle, in which a nominal torque characteristic, which indicates a transmissible clutch torque as a function of an actuator position, is adapted to a clutch-specific torque characteristic by a friction value adaptation.

From the WO 2016/008463 A1 a method for determining a Tastpunktänderung and for adapting a coefficient of friction of a hybrid disconnect clutch of a hybrid vehicle is known. To ensure that when the engine is restarted by an electric motor sufficient torque is provided by the electric motor, which both moves the hybrid vehicle via the drive wheels without loss of comfort and the engine starts simultaneously, a precise knowledge of a clutch characteristic of the hybrid disconnect clutch is required, which is a clutch torque over a Aktorweg maps. An interface of this clutch characteristic is a touch point, by which the position of the hybrid disconnect clutch is to be understood, in which the friction surfaces of the input or output part of the hybrid disconnect clutch in frictional contact with each other. The inclination of the clutch characteristic is determined by a coefficient of friction.

In a new clutch system, a theoretical torque characteristic is stored in the software in the clutch system, which changes in reality on the component distribution and on the operation, for example, the temperature. How out 3 can be seen, the theoretical torque characteristic curve is determined from a plurality of interpolation points, which are determined by scanning point and friction value adaptation (FIG. 4 ) is adapted to the real torque characteristic.

The interpolation points are recorded on a fixed actuator position by means of the coefficient of friction. The problem is that the torque characteristic of automated disconnect systems varies greatly in their inclination. The support points are shifted at very high friction to higher torque and at very low friction to lower torque. This means that the accuracy of the required operating range of the torque characteristic is changed by the displacement of the support points. Thus, the real determined torque characteristic is reproduced with less accuracy.

The invention has for its object to provide a method for adjusting a torque characteristic in which the real determined torque characteristic of a given clutch actuation system has a high accuracy.

According to the invention, the object is achieved in that during the friction value adaptation, the nominal characteristic is shifted via an actuator travel at a constant torque level, whereby the clutch-specific torque characteristic is determined. This has the advantage that the torque level remains constant in the considered operating range, whereby the accuracy of the clutch torque to be transmitted of the clutch actuating system is improved.

Advantageously, the Aktorweg by which the nominal characteristic is shifted, determined in dependence of a measured coefficient of friction. Since the coefficient of friction depends on the wear of the friction linings and other influencing variables of the coupling, the torque transmission is improved by the adaptation of the Aktorweges, which contributes to the accuracy of the torque characteristic curve of the clutch actually determined.

Advantageously, a touch point adaptation for shifting the nominal characteristic along the Aktorweges is performed. Since this touch point represents an essential interpolation point of the torque characteristic of the coupling, the accuracy is further increased by the additional touch point adaptation.

In one embodiment, the determination of the clutch-specific torque characteristic takes place during initial commissioning of the clutch actuation system. Here, the theoretical nominal torque curve, which is the basis of the newly built clutch actuation system, immediately adapted to the real conditions of the clutch actuation system.

In a further development, the determination of the clutch-specific torque characteristic takes place at predetermined intervals during operation of the clutch actuation system. Thus, a change in the wear conditions in the clutch actuation system over the aging process of the clutch is taken into account and the accuracy of the real torque curve continuously adjusted.

Advantageously, an automated disconnect clutch system is used as the clutch actuation system.

• 1 ein Ausführungsbeispiel eines Antriebsstranges zur Durchführung des erfindungsgemäßen Verfahrens,
• 2 ein Ausführungsbeispiel des erfindungsgemäßen Verfahrens,
• 3 ein Ausführungsbeispiel einer nominalen Kupplungskennlinie nach dem Stand der Technik,
• 4 ein Ausführungsbeispiel für einen Verfahrensablauf zum Lernen einer Kupplungskennlinie,
• 5 ein Vergleich zwischen einem Verfahren nach dem Stand der Technik und einem erfindungsgemäßen Verfahren.

Show it:

• 1 An embodiment of a drive train for carrying out the method according to the invention,
• 2 an embodiment of the method according to the invention,
• 3 An embodiment of a nominal clutch characteristic according to the prior art,
• 4 an embodiment of a method sequence for learning a clutch characteristic,
• 5 a comparison between a method according to the prior art and a method according to the invention.

In 1 is an embodiment of a drive train 1 a vehicle shown how it is used to carry out the method according to the invention. This is a hybrid powertrain of a vehicle. An internal combustion engine 2 is via a friction release clutch 3 with a motor and generator operable electric machine 4 connected, in turn, via an example hydraulic working torque converter 5 with an automated transmission 6 connected to the wheels 7 of the vehicle, not shown drives. The electric machine 4 Depending on the operating state, it works with an energy store 8th together, in generator operation of the electric machine 4 is charged and from the motorized operation of the electric machine 4 Energy is taken. The friction release clutch 3 is powered by a clutch actuator 9 actuated. To control the drive train described 1 serves an electronic control device 10 with inputs 11 equipped with sensors for detecting the operating state of the drive train 1 are connected. These sensors include, for example, an accelerator pedal sensor, a gear selector lever sensor, a speed sensor for detecting the rotational speed of the internal combustion engine, a load sensor for detecting the position of a load actuator of the internal combustion engine, and a sensor for detecting the rotational speed of the vehicle wheel. outputs 12 the electronic control device 10 are with actuators and other control devices for controlling the operation of the internal combustion engine 2 , the electric machine 4 , the automatic transmission 6 and optionally the converter 5 connected. Shown is only the connection of an output 13 the electronic control device 10 with the clutch actuator 9 ,

In a newly manufactured clutch actuation system, the software included in the controller 10 is stored for the clutch control, given a nominal torque characteristic. This is a theoretical characteristic which is based on the actual conditions of the friction-separating clutch 3 the clutch actuation system must be adapted, the torque curve is a clutch torque M over an actor way s indicates. This adaptation first takes place in a touch point determination, in which the nominal moment characteristic curve in x -Axis direction (Aktorweg s) is moved. With a friction value adaptation, the inclination of the nominal torque characteristic changes. In particular, in order to improve the accuracy of the inclination of the torque characteristic, is for individual bases of the friction clutch 3 determines a coefficient of friction and determines an actuator travel s with this determined coefficient of friction. This Aktorweg s is along a predetermined clutch torque M on the x Axis, which sets the real torque curve. This is related to 2 shown. The clutch moments M1 . M2 . M3 and the associated paths s1 . s2 and s3 represent the interpolation points of the nominal torque characteristic curve. The paths detected as a function of the coefficient of friction s1 * . s2 * . s3 * become moment at the respective moment level M1 . M2 . M3 shifted, with the respective moment level M1 . M2 . M3 is kept constant. The inclination of the real torque characteristic curve is based on the touch point T changed and thus achieved a real torque curve with a reliable accuracy.

This result is obtained by comparing the real characteristic K1 , which was determined according to the prior art and the real characteristic K2 , which was determined by the method according to the invention, in 5 clarified. It shows 5a the characteristics K1 . K2 at a low coefficient of friction, 5b at a high coefficient of friction and 5c at an initial coefficient of friction.

LIST OF REFERENCE NUMBERS

1

powertrain

2

internal combustion engine

3

Friction clutch

4

electric machine

5

torque converter

6

transmission

7

wheel

8th

energy storage

9

clutch actuator

10

control device

11

Inputs of the control device

12

Outputs of the control device

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2016/008463 A1 [0002]

Claims (6)

Method for adapting a torque characteristic of a clutch actuation system, preferably a motor vehicle, in which a nominal torque characteristic which indicates a transmissible clutch torque as a function of an actuator position, is adapted to a clutch-specific torque characteristic by a friction value adaptation, characterized in that during the Reibwertadaption the nominal characteristic via an Aktorweg is shifted at a constant torque level, whereby the clutch-specific torque characteristic is determined. Method according to Claim 1 , characterized in that the actuator travel, by which the nominal characteristic is shifted, is determined as a function of a measured coefficient of friction. Method according to Claim 1 or 2 , characterized in that a Tastpunktadaption is performed to shift the nominal characteristic along the Aktorweges. Method according to Claim 2 . 3 or 4 , characterized in that the determination of the separating clutch-specific torque characteristic takes place at a first commissioning of the clutch actuating system. Method according to at least one of the preceding claims, characterized in that the determination of the clutch-specific torque characteristic takes place at predetermined intervals during operation of the clutch actuation system. Method according to at least one of the preceding claims, characterized in that the clutch actuation system used is an automated disconnect clutch system.

Images