DE102014208781A1 - Method and control device for determining a reference point for a contact point of a coupling - Google Patents

Abstract

Method for determining a reference point for a contact point of a clutch (4) of a motor vehicle connected between a drive unit (1) and a transmission (3) with a drive unit-side coupling half (5) and a transmission-side coupling half (6). According to the invention, the clutch (4) is opened, the transmission-side coupling half (6) fixed the clutch (4) and detected in this state, an idling torque of the drive unit (1) and / or an idle speed of the drive unit (1), wherein subsequently when the motor vehicle is at a standstill, the clutch (4) is closed in a defined manner on the transmission side coupling half (6) and the torque of the drive unit (1) and / or the rotational speed of the drive unit (1) is monitored, namely in such a way that then, when starting from the idling torque of the drive unit (1) increases the same moment by more than a defined amount and / or starting from the idle speed of the drive unit (1) the same speed decreases by more than a defined amount, a corresponding clutch travel of the clutch (4) Reference point for the application point of the clutch (4) is determined.

Description

The invention relates to a method for determining a reference point for a contact point of a clutch and a control device for carrying out the method.

Between a drive unit and a transmission of a motor vehicle connected clutches serve primarily as a starting element. In order to control the operation of such a clutch exactly, the knowledge of the so-called clutch characteristic is required, the clutch characteristic is defined by defined characteristic points, u. a. by the so-called to-point of the clutch and by the so-called Anlegepunkt the clutch.

From the DE 10 2007 015 679 A1 It is known to determine the point to a clutch characteristic and the application point of a clutch characteristic, which according to the prior art, the application point of a clutch characteristic can only be detected if no gear is engaged in a stationary vehicle and running drive unit in the transmission.

From the DE 10 2011 014 236 A1 a method for operating a clutch of a drive train of a hybrid vehicle is known in which at standstill of the hybrid vehicle and with the internal combustion engine, a torque provided by the internal combustion engine is transmitted from the clutch to the electric machine of the hybrid vehicle, wherein the torque transmitted by the clutch and / or whose influence on the operation of the electric machine is detected and evaluated in order to determine the point of application of the clutch.

On this basis, the present invention based on the object to provide a novel method for determining a reference point for a contact point of a clutch and a control device for carrying out the method.

This object is achieved by a method for determining a reference point for a contact point of a coupling according to claim 1.

According to the invention, the clutch is opened at standstill of the motor vehicle fixed, the transmission side clutch half of the clutch and detected in this state, an idle torque of the drive assembly and / or idle speed of the drive unit, which is subsequently closed at rest of the motor vehicle, the clutch is still defined geared coupling half and closed In this case, the moment of the drive unit and / or the rotational speed of the drive unit is monitored, namely such that when starting from the idling torque of the drive unit, the same torque increases by more than a defined amount and / or starting from the idle speed of the drive unit the same speed decreases by more than a defined amount, a corresponding clutch travel of the clutch is determined as a reference point for the application point of the clutch.

With the present invention, a method is proposed, which does not serve to determine the application point of the coupling, but rather the determination of a close to the application point of the coupling reference point or auxiliary point for the application point of the coupling.

With the help of the method according to the invention, this reference point can be reliably and accurately determined even when a gear is engaged in the transmission. For this purpose, the transmission-side coupling half is fixed at a standstill of the motor vehicle with the drive unit running and with the clutch open. Subsequently, when the motor vehicle is stopped and the transmission side clutch half is fixed, the clutch is closed and the reference point for the application point of the clutch is determined from the resulting torque curve of the drive unit and / or the resulting speed curve of the drive unit.

Preferably, the idling torque of the drive unit is detected at a standstill of the motor vehicle with the clutch open and fixed transmission-side clutch half of the clutch, which is subsequently closed when the motor vehicle, the clutch still set at the transmission side coupling half and active idle speed controller.

Here, the moment of the drive unit is monitored such that when starting from the idling torque of the drive unit, the same momentum by more than a defined amount, a corresponding clutch travel of the clutch is determined as a reference point for the application point of the clutch, namely that clutch travel at starting from the idling torque of the drive unit, the same moment increases by more than the defined amount. The torque of the drive unit is determined by calculation from a demanded by the idle speed controller fuel injection quantity. This procedure for determining the reference point of the application point of the coupling is preferred.

Preferably, the transmission-side coupling half of the clutch is set via a transmission brake, wherein a gear is engaged in the transmission and remains engaged. This can be determined continuously in the stop-and-go operation of the motor vehicle, the reference point for the application point.

The control device according to the invention is defined in claim 7.

Preferred developments emerge from the subclaims and the following description. Embodiments of the invention will be described, without being limited thereto, with reference to the drawings. Showing:

1 a powertrain diagram of a motor vehicle;

2 a flow diagram illustrating the method for determining a reference point for a contact point of a clutch;

3 a first timing diagram to illustrate a first embodiment of the method according to the invention; and

4 a second time chart to illustrate a second embodiment of the method according to the invention.

The present invention relates to a method for determining a reference point or an auxiliary point for a contact point of a clutch and a control device for carrying out the method.

1 shows a schematic of a powertrain of a motor vehicle, wherein between a drive unit 1 and a downforce 2 of the motor vehicle a transmission 3 is switched. Between the transmission 3 and the drive unit 1 is a clutch 4 with a drive unit-side coupling half 5 and a transmission-side coupling half 6 connected. At the clutch 4 it is a friction clutch with a defined clutch characteristic, which serves as a starting clutch.

1 further shows a motor control device 7 and a transmission control device 8th wherein the engine control device 7 for controlling and / or regulating the operating drive assembly 1 with the drive unit 1 Data exchanges, and wherein the transmission control device 8th for controlling and / or regulating the operation of the transmission 3 with the gearbox 3 Exchanges data. Further, the engine control means exchange 7 and the transmission control device 8th with each other data. The coupling 4 is preferably based on the transmission control device 8th driven.

As already stated, it is between the drive unit 1 and the gearbox 3 switched clutch 4 to a friction clutch with a defined clutch characteristic, wherein a relevant clutch characteristic point of the clutch characteristic is the so-called application point. The invention now relates to a method by means of which a reference point or auxiliary point for the application point of such a coupling 4 can be determined.

The method according to the invention will be described below with reference to FIG 2 to 4 described in detail, the block 9 of the signal flow diagram of 2 the start of the method for determining the reference point for the application point of the coupling 4 visualized, and where the block 10 visualized the end of the procedure.

After starting the procedure in block 9 will be in a subsequent block 11 at standstill of the motor vehicle while the drive unit is running 1 the coupling 4 opened so that it does not transmit a moment, with the coupling-side coupling half 6 the clutch 4 is set, in particular via a transmission brake of the transmission 3 , In this state, an idle torque of the drive unit 1 detected.

The determination of the idling torque of the drive unit in block 11 with the clutch open 4 and fixed gear-side coupling half 6 takes place over a defined period of time, being in a block 12 an average of the idling torque of the drive unit detected in this period 1 is determined. By averaging a signal noise is smoothed and improves the signal quality accordingly. As an alternative or in addition to averaging, the signal can also be filtered for signal processing, for example by means of a PT1 filter with a corresponding time constant.

Following this, according to the block 13 at standstill of the motor vehicle and still fixed gearbox side coupling half 6 the coupling 4 defined closed, preferably linearly via a ramp, in which case, ie parallel to the block 13 , according to the block 14 the here forming moment of the drive unit 1 is monitored, namely such that when starting from the in the blocks 11 and 12 certain idling torque of the drive unit 1 the moment of the drive unit 1 increases by more than a defined amount ΔM, a corresponding clutch travel of the clutch 4 as a reference point or auxiliary point for the application point of the coupling 4 is determined.

Subsequently this is in a block 15 the coupling 4 fully opened again and the transmission side coupling half 6 for example, released by releasing the transmission brake.

3 illustrates this procedure for determining the reference point or auxiliary point for the application point of the coupling 4 on the basis of a time diagram, in 3 over time t, on the one hand, the moment M of the drive unit 1 and on the other hand, the clutch travel S of the clutch 4 is applied. At the beginning of the process at time t0 is the clutch 4 fully open, the transmission side coupling half 6 is set. Subsequently, the determination of the idling torque of the drive unit takes place until time t1 1 where, starting with the time t1 in the sense of the blocks 13 and 14 the coupling 4 is closed defined, namely according to 3 ramp-like linear, in which case the forming moment M of the drive unit 1 is monitored. At time t2 decreases, starting from the idling torque of the drive unit 1 , the moment M of the same by more than the defined amount .DELTA.M, so that at the time t2 valid clutch path S2 as the reference point or auxiliary point for the application point of the clutch 4 is determined.

In the above procedure is an idle speed controller of the drive unit 1 that is typically in the engine control device 7 is implemented, active. By the ramp-like closing of the clutch 4 beginning with the time t1 increases the transmission capacity of the clutch 4 so that from a defined clutch travel of the clutch 4 the idle speed controller a larger amount of fuel injection for the drive unit 1 request, so that the idle speed controller the idle speed of the drive unit 1 can keep constant.

From this demanded by the idle speed controller injection quantity and from the maximum engine torque M _MAX , the engine torque M of the drive unit 1 determined by calculation, in particular according to the following formula: M = AEPT · M _MAX where M _{MAX is} the maximum engine torque of the drive unit 1 is, where M is to be monitored engine torque M of the drive unit 1 and AEPT is a characteristic dependent on the demanded by the idle speed controller injection quantity, which is referred to as Actual Engine Percent Torque.

Although the determination of the reference point for the application point of the coupling 4 based on the torque curve of the drive unit 1 is preferred, it is also possible, the reference point based on the speed curve of the drive unit 1 to determine. This will be explained below with reference to 4 described. So shows 4 a time chart in which over time t, on the one hand, the speed n of the drive unit 1 and on the other hand, the clutch travel S of the clutch 4 is applied.

In the embodiment of 4 is used to determine the reference point at standstill of the motor vehicle with the clutch open 4 and with fixed, gearbox-side coupling half 6 the clutch 4 initially detects an idle speed of the drive unit, namely preferably between the times t0 and t1 with appropriate averaging. By averaging a signal noise is smoothed and improves the signal quality accordingly. As an alternative or in addition to averaging, the signal can also be filtered for signal processing, for example by means of a PT1 filter with a corresponding time constant.

Beginning at time t1, the clutch becomes 4 closed, namely at a standstill of the motor vehicle while still fixed gearbox side coupling half 6 , In this case, the speed n of the drive unit 4 is monitored.

Then, when starting from the idle speed of the drive unit, the speed thereof decreases by more than a defined amount .DELTA.n, the corresponding clutch S2 is used as a reference point for the application point of the clutch 4 certainly.

The inventive method can be carried out both when the transmission 3 is in neutral, as well as when, when the motor vehicle is in the transmission 3 a gear is engaged.

Preferably, the engine torque is active at idle speed controller of the drive unit 1 evaluated to the reference point of the application point of the clutch 4 to determine. By offsetting this reference point with an empirically determined offset value from the reference point of the application point of the clutch 4 be determined.

The present invention further relates to a control device for carrying out the method.

This control device is preferably the transmission control direction 8th ,

The control device comprises means for carrying out the method according to the invention. These resources are hardware and software resources. The hardware-side means are data interfaces in order to exchange data with the modules performing the method according to the invention. Furthermore, the hardware means are a processor and a memory, a memory for storing data and a processor for processing data. The software resources are program modules for carrying out the method according to the invention.

The above method for determining the reference point for the application point of between the drive unit 1 and the gearbox 3 switched clutch 4 is executed on the control side as often as possible in order to continuously redetermine the reference point for the application point and thus, for example, to detect a displacement of the reference point, and thus of the application point, which is prevented by a high coupling load.

It can be provided to secure the determination of the reference point for the application point via a plausibility check, e.g. in that outliers, which differ from previously determined reference points, which deviate by more than a percentage factor from the previously determined reference points, are filtered out.

The clutch travel signal S (t) and the torque signal M (t) and / or the rotational speed signal n (t) can be used to provide a respective smoothed signal processing such as signal processing. be subjected to a filtering.

LIST OF REFERENCE NUMBERS

1

power unit

2

output

3

transmission

4

clutch

5

coupling half

6

coupling half

7

Motor controller

8th

Transmission control device

9

block

10

block

11

block

12

block

13

block

14

block

15

block

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 102007015679 A1 [0003]
• DE 102011014236 A1 [0004]

Claims (7)

A method for determining a reference point for a contact point of a switched between a drive unit and a transmission clutch of a motor vehicle with a drive unit-side coupling half and a transmission-side coupling half, characterized in that when the motor vehicle, the clutch is opened, the transmission-side coupling half of the clutch fixed and in this state an idling torque of the drive unit and / or an idling speed of the drive unit is detected; Subsequently, when the motor vehicle is at a standstill, the clutch is closed defined while the transmission side coupling half is fixed and the torque of the drive unit and / or the rotational speed of the drive unit is monitored, namely such that, when starting from the idling torque of the drive unit, the torque is increased by more than rises a defined amount and / or starting from the idle speed of the drive unit, the speed thereof decreases by more than a defined amount, a corresponding clutch travel of the clutch is determined as a reference point for the application point of the clutch. A method according to claim 1, characterized in that the idling torque of the drive unit is detected at a standstill of the motor vehicle with the clutch open and fixed on the transmission side clutch half, that then closed when the motor vehicle, the clutch at defined fixed gear side clutch half and active idle speed controller is closed , And that in this case the moment of the drive unit is monitored such that when starting from the idling torque of the drive unit, the same moment by more than a defined amount, a corresponding clutch travel of the clutch is determined as a reference point for the application point of the clutch. A method according to claim 1 or 2, characterized in that the torque of the drive unit is determined by calculation from a demanded by the idle speed controller fuel injection quantity. A method according to claim 1, characterized in that the idling speed of the drive unit is detected at a standstill of the motor vehicle with the clutch open and fixed gear side coupling half of the clutch, that then closed at a fixed set gear side coupling half is closed at standstill of the motor vehicle and in this case the speed the drive unit is monitored, namely such that when starting from the idle speed of the drive unit, the speed of the same decreases by more than a defined amount, a corresponding clutch travel of the clutch is determined as a reference point for the application point of the clutch. Method according to one of claims 1 to 4, characterized in that the transmission-side coupling half of the clutch is set via a transmission brake. Method according to one of claims 1 to 5, characterized in that in this case a gear is engaged in the transmission and remains engaged. Control device of a motor vehicle, in particular transmission control device of an automatic transmission, characterized by means for carrying out the method according to one of claims 1 to 6.

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