JP2018509574A - Method for adapting the clutch model of an automatic clutch by adjusting the friction value of the clutch - Google Patents

Abstract

The present invention relates to a method for adapting a clutch model of an automatic clutch by adjusting a friction value of the clutch (5, 6). In this method, an actual friction value during a slip period of the clutch (5, 6) is obtained, If the actual slip rate (k _s) exceeds a predetermined slip rate threshold (n _s), adjusts the coefficient of friction. In the method of increasing the number of adaptation situations during the driving operation of the vehicle, the friction value is adjusted depending on the state of “inaccuracy of the rotational speed signal of the internal combustion engine (2) or the transmission input shaft (9, 10)”. Increase the sliding speed threshold ( _ns ) to be performed.

Description

  The present invention relates to a method for adapting a clutch model of an automatic clutch by adjusting a friction value of the clutch. In this method, an actual friction value during a slip period of the clutch is obtained, and the actual slip speed is a predetermined slip speed threshold value. If it exceeds, adjust the friction value.

  In order to better meet the comfort requirements of a vehicle, a clutch arranged between the internal combustion engine and the transmission and transmitting the torque of the internal combustion engine to the drive system must be operated as accurately as possible. Since the clutch has a temporally variable characteristic, for example under the influence of temperature changes, a clutch model is required, which must be adapted periodically. The adjustment of the friction value of the clutch model can be applied only when there is a clutch slip that can be reliably determined.

  German Patent Application No. 102010024941 describes a method of controlling a dual clutch transmission having two partial drive trains, each of which is coupled to an internal combustion engine using a clutch. be able to. During the running operation of a vehicle equipped with a dual clutch transmission, the clutch sampling point is determined without depending on the engine torque. Thus, this sampling point is determined during vehicle startup and is adapted during vehicle operation.

  From WO 2008/064633 a method and device for adapting a hybrid separation clutch of a vehicle hybrid drive system is known which stops the internal combustion engine and releases the hybrid separation clutch after the internal combustion engine is shut off. Next, a time gradient of the rotational speed of the internal combustion engine is acquired with the internal combustion engine shut off and the hybrid separation clutch released. In the case of the half clutch of the hybrid separation clutch, the time gradient of the rotational speed of the internal combustion engine at the time of the half clutch of the clutch is obtained immediately when the rotational speed of the internal combustion engine falls below a predetermined value. Next, the characteristic curve of the hybrid separation clutch is adapted based on the obtained clutch torque transmitted by the hybrid separation clutch at the time of the half clutch. This clutch characteristic curve is represented by the sampling point and the friction value, and the state of the vehicle and the clutch changes. Therefore, both the sampling point and the friction value must be adjusted.

  If the rotational speed signal of the internal combustion engine or the transmission input shaft is not accurate, for example if it indicates an offset error or time delay, it may be erroneously determined that the clutch is slipping despite the clutch being in close engagement. obtain. Such determination results in erroneous adaptation of the clutch model.

FIG. 3 shows a general method when the state “accuracy” of the rotational speed of the internal combustion engine or the transmission input shaft is generated, and a general method when the state “inaccuracy” occurs. When the signal state “accurate” is transmitted, the clutch operation exhibits the characteristics as shown for section C. In such a case, without the hands slip speed threshold n _s of performing friction value adjustment. On the other hand, as shown in the section D, when the signal state “inaccurate” is transmitted, the slip exceeds the region ss where the slip and the close contact of the clutch cannot be reliably distinguished. However, no adaptation of the friction value is performed. This is indicated by an adaptation bit b _a equal to 0. This is not done even if a large slip occurs, for example during a “creep” of the vehicle. In such a case, the clutch model becomes unresponsive to any change in the friction value. In this case, even if the actual friction value changes, the clutch model does not follow the change, so that a significant clutch model error occurs. This ultimately results in an error in the estimated clutch torque.

  In the case of a normal driving situation, many adjustment means for the friction value remain unused even depending on the “rotational speed inaccuracy” state of the internal combustion engine or the transmission input shaft. Therefore, the frequency of applying the friction value is reduced, and this also makes it impossible to control the clutch model following the change in the friction value. As described above, there is an error in estimation of the clutch model, so that the driving comfort is deteriorated.

  An object of the present invention is to realize a method for adapting a clutch model of an automatic clutch by adjusting a friction value, which can calculate a friction value by distinguishing slip and clutch attachment with high reliability.

  In the present invention, the above problem is solved by increasing the slip speed threshold for adjusting the friction value depending on the state of “inaccuracy of the rotational speed of the internal combustion engine or the transmission input shaft”. Increasing the sliding speed threshold eliminates the need to abandon all adaptation situations and ensures that only adaptation situations below this increased sliding speed threshold need be abandoned. By increasing the slip speed threshold, the possibility of confusion between the slip of the clutch and the contact state is prevented with high reliability. The slip speed threshold rises to the extent that it can be reliably determined that the clutch is in a slip state when the slip exceeds the increased slip speed threshold. Thus, an accurate clutch torque can be provided even in the case of an “inaccuracy in the rotational speed of the internal combustion engine or transmission input shaft” state in which the rotational speed indicates an offset error and / or time delay, for example. , Running comfort is maintained at a high level.

  In one embodiment, the sliding speed threshold for adjusting the friction value is increased depending on the state of “inaccuracy of the rotational speed of the internal combustion engine or the transmission input shaft”. This supports a situation in which clutch slip is generated artificially, and an additional period for applying the clutch model can be added.

  In one embodiment, the actual friction value is determined by comparing the clutch torque with the torque of the internal combustion engine.

  In another embodiment, the friction value adjustment is terminated when the actual sliding speed falls below the raised sliding speed threshold. This makes it possible to reliably narrow down the period during which adaptation is performed.

  Many embodiments are possible with the present invention. One of these embodiments will be described in detail with reference to the figures in the drawings.

It is a basic diagram of a dual clutch transmission. FIG. 3 shows an embodiment of the method of the present invention. FIG. 2 is a diagram illustrating an example of a prior art method.

  The method of the present invention will be described using the dual clutch transmission 1 as an example. However, this example does not limit the invention and can be applied to all possible transmissions with clutches.

FIG. 1 is a basic view of a dual clutch transmission 1 as used in an automobile. The dual clutch transmission 1 is connected to an internal combustion engine 2 and includes two partial systems 3 and 4. Each partial system 3, 4 and the internal combustion engine 2 are connected via clutches 5, 6 operated by the control unit 15. The first partial system 3 includes odd stages 7, and the second partial system 4 includes even stages 8. These gear stages 7 and 8 are connected to transmission input shafts 9 and 10 of the transmission 11 when necessary, and the transmission 11 drives the drive wheels 14 via the differential transmission device 12 and the drive shaft 13. The rotational speed n _v of the internal combustion engine 2 is detected by the rotational speed sensor 16, and the rotational speed n _G of the transmission input shaft 9 is measured by the rotational speed sensor 17. Both the rotational speed sensors 16 and 17 are connected to the control unit 15.

  In such a dual clutch transmission 1, the gear stage 7 of the partial system 3 is connected to the transmission input shaft 9 while the gear stage 8 of the other partial system 4 is put on. In order to do this, the characteristics of both clutches 5 and 6 must be set accurately in order to avoid disturbance. Each of the clutches 5 and 6 is controlled using a clutch model stored in the control unit 15. The parameter of this clutch model is the friction value, which needs to be applied regularly during vehicle operation. In order to adapt the friction value, the clutch 5 will be described. The clutch 5 operates in a sliding state to transmit the clutch torque. However, this is true for the clutch 6 as well. The clutch torque is compared with the torque of the internal combustion engine 2 during the slip period of the clutch 5, and the friction value is obtained from this comparison.

Prior to the application of the friction value, the internal combustion engine speed _nv and the transmission input shaft speed _nG are evaluated. Internal combustion engine state of the rotating speed n _v or transmission input shaft speed n _G is "correct" (Figure 2, section A) if it is, may be confused with the adhesion of the clutch 5 unable reliably determine the slip of the clutch 5 It is determined that the sliding speed region ss is very small. When the sliding speed k _s exceeds a predetermined sliding speed threshold value n _s , an adaptation bit b _a that permits adaptation of the friction value is set (FIG. 2a). In such a region, the rotational speed n _K of the clutch corresponding to the rotational speed n _v of the internal combustion engine 2 exceeds the rotational speed n _G of the transmission input shaft 9. As can be seen from FIG. 2c, in which the slip of the clutch 5 is represented on the time t-axis, the slip speed region ss in which the slip generated in the clutch 5 is slight and confusion between the close engagement of the clutch and the slip can occur is very high. small. Since the slip rate k _s is beyond the sliding speed threshold n _s, adapting the coefficient of friction. Here, the target speed k _s of the slip corresponding to the slip request is not changed.

The section B, and shows the rotational speed of the characteristic when one of the state of the internal combustion engine speed n _v or transmission input shaft speed n _G becomes "inexact". Specifically, the rotational speed indicates, for example, an offset error and / or a time delay. In such a case, since the slip speed region ss where the slip cannot be reliably determined is large, the minimum slip speed threshold for adaptation is also raised. The target slip threshold is raised as shown in FIG. 2c to ensure that a slip that can be reliably determined (sufficiently large) occurs. Even when the actual sliding speed k _s exceeds the raised sliding speed threshold value n _s , the adaptive bit b _a that permits the friction value adjustment is set. At the same time, the target slip _{nz for} adjusting the friction value is raised. This will increase the sliding speed k _s over time as shown in FIG. 2b.

  With the solution disclosed here, it is possible to adapt the friction value even in the “rotational speed signal inaccurate” state, so that the clutch model can always follow the change of the friction value characteristic.

DESCRIPTION OF SYMBOLS 1 Dual clutch transmission 2 Internal combustion engine 3 Partial system 4 Partial system 5 Clutch 6 Clutch 7 Shift stage 8 Shift stage 9 Transmission input shaft 10 Transmission input shaft 11 Transmission 12 Differential transmission device 13 Drive shaft 14 Drive wheel 15 Control unit 16 Number of rotations Sensor 17 Speed sensor n _v Internal combustion engine speed n _G Transmission speed b _a Adaptation bit n _K Clutch speed n _z Target slip k _s Slip speed _ns Slip speed threshold ss Slip speed range

Claims (4)

A method for adapting a clutch model of an automatic clutch by adjusting a friction value of the clutch (5, 6),
Obtain the actual friction value during the sliding period of the clutch (5, 6),
When the actual slip speed (k _s) exceeds a predetermined slip rate threshold (n _s), the method of adjusting the coefficient of friction,
The slip speed threshold value ( _ns ) for adjusting the friction value is increased depending on the state of "inaccuracy of the rotational speed signal of the internal combustion engine (2) or the transmission input shaft (9, 10)". And how to.   The target rotational speed of the internal combustion engine (2) corresponding to a slip request is increased depending on the state of "inaccuracy of rotational speed signal of the internal combustion engine (2) or transmission input shaft (9, 10)". The method according to 1.   The method according to claim 1, wherein the actual friction value is obtained by comparing a clutch torque with a torque of the internal combustion engine. The method according to any one of claims 1 to 3, wherein the adjustment of the friction value is terminated when the sliding speed (k _s ) falls below a raised sliding speed threshold ( _ns ).

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