DE102017127918A1 - Method for controlling an automated clutch - Google Patents

Abstract

The invention relates to a method for controlling an automated clutch, in particular for a vehicle, in which in a hydraulic clutch system (1) arranged clutch (13) by a hydrostatic actuator (2) in response to a characteristic (Kp) is actuated, wherein the characteristic curve (Kp) is determined by a pressure occurring in the hydraulic clutch system (1). In a method in which the drive is optimized, a pressure rise position (p) of the characteristic curve (Kp) characterizing the beginning of actuation of the clutch (13) is measured, which is arranged in a position of a predetermined pressure actuator travel-dependent coordinate system which corresponds to a maximum moment.

Description

The invention relates to a method for controlling an automated clutch, in particular for a vehicle, in which the arranged in a hydraulic clutch system clutch is actuated by a hydrostatic actuator in response to a characteristic, wherein the characteristic is determined by a pressure occurring in the hydraulic clutch system.

From the DE 10 2011 103 774 A1 For example, there is known a method of driving an automated clutch that is actuated by a hydrostatic actuator. In this case, a load signal of the hydrostatic actuator is used to determine a sniffer position of a clutch encoder. The control of the clutch takes place via a clutch characteristic, which represents a transmitted clutch torque on a Aktorweg, which is stored in a Ansteuersoftware. A minimum position of the Aktorweges is defined by a snoop position, ie the position at which a Schnüffelnut is securely opened to adjust the volume of hydraulic fluid. The maximum position of the Aktorweges is defined by the coupling itself and by the geometry of the slave cylinder. In addition, a zero position is defined in which, taking account of design-relevant tolerances, the sniffer groove is always closed.

To open the clutch, the positions of the characteristic are controlled, which are above the zero position up to a maximum position of the actuator. The positions smaller than the zero position are actuated to equalize the pressure of the fluid path through the actuator. A pressure rise position at which a pressure build-up begins in the characteristic line, which is equivalent to the beginning of a clutch actuation in the clutch-open direction, is thus by definition smaller than the zero position. However, this pressure rise position is subject to tolerances. Therefore, this pressure rise position is firmly defined in the design and rating of the software in the characteristic curve. This has the consequence that on the one hand, the clutch must be designed for a larger Ausrückweg by these scatters to open them. On the other hand, the coupling must be designed for a correspondingly higher torque capacity by the occurring in the zero position preload, which has a reduced contact pressure of the clutch to compensate for the effect of preload.

The invention has for its object to provide a method for controlling an automated clutch, wherein the control of the clutch is improved by reducing the torque capacity while minimizing the space of the coupling system.

According to the invention the object is achieved in that a beginning of an actuation of the clutch pressure-increasing position of the characteristic curve is measured, which is arranged in a position of a predetermined pressure Aktorweg-dependent coordinate system, which corresponds to a maximum torque of the clutch. This has the advantage that a targeted control of the clutch without provision of the pressure increase variations is possible. This eliminates the applied preload, whereby the maximum torque is reached because the actuator is in a closed sniffer position. This allows an actuator stroke as well as the maximum actuation stroke of the coupling to be reduced, with the result that the components can be optimized in terms of installation space and component load.

Advantageously, the position for transmitting the maximum torque corresponds to a zero position of the predetermined coordinate system. This zero position determines the position of the actuator, in which the Schnüffelnut is always closed. This position corresponds to an approximately force-free adjustment of the actuator, in which the clutch ideally sees no release force. Such a method is widely applicable for a variety of coupling designs, with design-dependent, temperature-dependent or slave piston dependent tolerances can be reliably detected and taken into account in the determination of the pressure rise position.

In one embodiment, starting from the pressure rise position, the actuator positions corresponding to the pressure rise of the characteristic line are aligned. These actuator positions, which make up the characteristic curve, are reliably in the positive range of the movement of the actuator, wherein the space available size is smaller than in the known from the prior art method.

In a variant, the pressure rise position is determined by detecting a pressure level. Alternatively, the pressure rise position may be determined by detecting a pressure gradient. In a further alternative, the pressure rise position is determined via an intersection of a regression curve to be determined via the pressure rise. Depending on the expected accuracy, the various methods for determining the pressure rise position can be selected or used for plausibility parallel to each other.

In a development, a distance between the pressure rise position and a position of the clutch actuator, in which a pressure and volume compensation of a hydraulic medium is carried out in the hydraulic clutch system, set. Since the distance to the so-called Sniffing position, in which the pressure equalization takes place, is known at zero position for each coupling design, this must always be stored only in the control software, so that starting from the zero position of the actuator, the snoop position can be calculated at any time. An additional measurement of the sniffer position is eliminated, which speeds up the process for controlling the automated clutch.

In one embodiment, a minimum translation of the path of the actuator to a disengagement of the clutch is taken into account for determining a maximum travel of the actuator for complete opening of the clutch. The consideration of this minimum ratio is necessary to operate the minimum lift of the clutch.

In one embodiment, the pressure rise position is adapted at predetermined time intervals. This ensures that the pressure rise position assumes its current value at any point in time when the clutch is actuated so that reliable and more accurate activation of the automated clutch can take place.

The invention allows numerous embodiments. One of them will be explained in more detail with reference to the figures shown in the drawing.

• 1 einen schematischen Aufbau eines hydraulischen Kupplungssystems,
• 2 eine schematische Darstellung einer Druck-Weg-Kennlinie der Kupplung gemäß dem erfindungsgemäßen Verfahren,
• 3 eine schematische Gegenüberstellung der Wirkung des erfindungsgemäßen Verfahrens und des Standes der Technik

Show it:

• 1 a schematic structure of a hydraulic coupling system,
• 2 a schematic representation of a pressure-displacement curve of the coupling according to the inventive method,
• 3 a schematic comparison of the effect of the method and the prior art

In 1 is a schematic structure of an automated coupling system 1 using the example of a hydrostatic clutch actuator shown schematically 2 (HCA), how it is used in vehicles. The coupling system 1 includes on a donor side 3 a control unit 4 which is an electric motor 5 controls, in turn, a threaded spindle 6 for converting the rotation of the electric motor 5 in a translational motion of a piston 7 that drives inside a master cylinder 8th is mounted axially movable. The electric motor 5 , The piston 7 as well as the master cylinder 8th form the hydrostatic clutch actuator 2 ,

Causes a rotary motion of the electric motor 5 a change in position of the piston 7 in the master cylinder 8th along the coupling path to the right, is the volume of the master cylinder 8th changed, causing a pressure p in the master cylinder 8th is built, which has a pressure medium 9 in the form of a hydraulic fluid via a hydraulic line 10 to the recipient side 11 of the hydraulic coupling system 1 is transmitted. On the taker side 11 causes the pressure p of the pressure medium 9 in a slave cylinder 12 a change of direction on a clutch 13 is transmitted to operate this.

The master cylinder 8th , the hydraulic line 10 and the slave cylinder 12 form thereby the hydraulic distance. The slave cylinder 12 engages to actuate the clutch 13 in a release bearing 14 one, which is against the tongues of a plate spring 15 pushes and thus the clutch 13 emotional.

The pressure p in the hydraulic system is controlled by a pressure sensor 16 measured, which at the master cylinder 8th is positioned. Also, the position change of the piston 7 is via a further displacement sensor 17 on the master cylinder 8th detected.

To control the clutch 13 via the control unit 4 is using the signals from the pressure sensor 16 and the displacement sensor 17 a characteristic kp recorded as they are in 2 is shown. A pressure rise position x _A is being measured. The detection of the pressure rise position p _A can be done by detecting a pressure level, by detecting a pressure gradient or via an intersection of the regression curve to be determined by the pressure increase. The distance x1 between pressure rise position and sniffer position can be learned and stored.

In the control software of the control unit 4 is given a pressure-displacement coordinate system, in which the recorded characteristic kp is inserted so that the pressure rise position p _A the characteristic kp is entered approximately at the point in the coordinate system where the maximum torque of the clutch 13 is transmitted. This is the zero position in the given coordinate system. The maximum opening position for the clutch 13 is with x2 _optimized designated. The distance between the position x _A and x2 _optimized corresponds to the Abhub (Ausrückweg) of the clutch 13 taking into account a translation between Aktorweg and the clutch travel corresponding Ausrückweg. Between Abhub and Ausrückweg the clutch is an additional translation by a lever of the diaphragm spring.

After adaptation of the pressure rise position p _A the pressure characteristic Kp in the predetermined coordinate system, the positive actuator positions are aligned.

The pressure rise position p _A defines the beginning of the clutch operation. To define the maximum actuator travel position x2 _optimized in which the clutch 13 is completely open, must correspondingly a minimum translation of Aktorweges x to Ausrückweg x _K the clutch 13 be considered to actuate the minimum lift on the coupling level.

In 3a is the characteristic kp shown, which was determined by a method according to the prior art. The arrows PF characterize the variations of the characteristic curve kp , The pressure rise position x _A is located between the actuator positions x1 and 0, where - x1 represents a position of the actuator, wherein the pressure equalization of the pressure medium 9 he follows. The maximum position x2 _optimized of the actor 2 to achieve the maximum opening of the coupling 13 is thus smaller than the maximum position x2 according to the prior art.

In 3b is the lift of the clutch 13 over the Ausrückweg x _K the clutch 13 illustrated where it is clear that a actuation of the clutch 13 is reduced by the way B, since a minimum lift (point C ) is more likely to be achieved by the proposed method.

In principle, when setting the pressure rise position in the coordinates 0 - 0 In the specified pressure-distance - coordinate system to reach a maximum torque of the clutch when no preload is applied, ie the actuator is in snoop position. However, since the area of the Schnüffelnut must not be run over with high dynamics, the system is operated with closed Schnüffelnut to open the clutch as quickly as possible.

LIST OF REFERENCE NUMBERS

1

coupling system

2

actuator

3

donor side

4

control unit

5

electric motor

6

screw

7

piston

8th

Master cylinder

9

lever

10

hydraulic line

11

recipient side

12

slave cylinder

13

clutch

14

release bearing

15

Belleville spring

16

pressure sensor

17

displacement sensor

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

• DE 102011103774 A1 [0002]

Claims (9)

Method for controlling an automated clutch, in particular for a vehicle, in which the clutch (13) arranged in a hydraulic clutch system (1) is actuated by a hydrostatic actuator (2) as a function of a characteristic (Kp), the characteristic (Kp ) is determined by a pressure occurring in the hydraulic clutch system (1), characterized in that a pressure rise position (p _A ) of the characteristic curve (Kp) characterizing the beginning of an actuation of the clutch (13) is measured, which is in a position of a predetermined pressure Aktorweg-dependent coordinate system is arranged, which corresponds to a maximum torque. Method according to Claim 1 , characterized in that the position for transmitting the maximum torque corresponds to a zero position of the predetermined coordinate system. Method according to Claim 1 or 2 , characterized in that, starting from the pressure rise position (pA), the actuator positions corresponding to the pressure rise of the characteristic curve (Kp) are aligned. Method according to Claim 1 . 2 or 3 , characterized in that the pressure rise position (pA) is determined by detecting a pressure level. Method according to at least one of the preceding claims, characterized in that the pressure rise position (pA) is determined by detecting a pressure gradient. Method according to at least one of the preceding claims, characterized in that the pressure rise position (pA) is determined via an intersection of a regression curve to be determined via the pressure rise. Method according to at least one of the preceding claims, characterized in that a distance between the pressure rise position (pA) and a position (-x1) of the actuator (2), in which a pressure and volume compensation in the hydrostatic actuator (2) is executed, predetermined becomes. Method according to at least one of the preceding claims, characterized in that for determining a maximum travel of the actuator (2) for complete opening of the clutch (13) a minimum translation of the path (x) of the actuator (2) to a Ausrückweg (xK) of Coupling (13) is taken into account. Method according to at least one of the preceding claims, characterized in that the pressure rise position (pA) is adapted at predetermined time intervals.

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