DE102013201317A1 - Method for determining a clutch torque request - Google Patents

Abstract

A method for determining a tactile point of a friction clutch device having a first friction clutch and a second friction clutch in a motor vehicle, the motor vehicle having an internal combustion engine and a transmission device, the transmission device comprising a first partial transmission with a first input shaft and a second partial transmission with a second input shaft, each using a friction clutch of the friction clutch device can be coupled to the internal combustion engine and / or decoupled from the internal combustion engine, wherein initially determined in a driving operation in a decoupled from the engine part gear with gear ratio geared a drag torque of the input shaft of this sub-transmission, subsequently using an operation of an associated friction clutch based on a Clutch torque request built a clutch torque and then from the drag torque and the clutch torque a buzzing is formed at a determination of the clutch torque request, the clutch torque request is limited to improve the process.

Description

The invention relates to a method for determining a touch point of a friction clutch device with a first friction clutch and a second friction clutch in a motor vehicle, the motor vehicle having an internal combustion engine and a transmission device, the transmission device comprising a first partial transmission with a first input shaft and a second partial transmission with a second input shaft , Which can be coupled by means of a friction clutch of the friction clutch device with the internal combustion engine and / or decoupled from the internal combustion engine, wherein first in a driving operation in a decoupled from the engine part gear with gear ratio geared a drag torque of the input shaft of this sub-transmission determined, subsequently by means of an operation of an associated Friction clutch based on a clutch torque request built a clutch torque and subsequently from the drag torque and the K moment a momentum is formed.

From the DE 10 2010 024 941 A1 a method is known for controlling a dual-clutch transmission with at least two sub-drive trains, each of which can be coupled by means of a clutch to an internal combustion engine, wherein the following steps are carried out on the inactive part-drive train: change with the clutch disengaged from an engaged gear to neutral; Determining the drag torque M _{S of} the input path of the inactive sub-drive train during a predetermined time period P1; Closing the clutch of the inactive sub-drive train to a predetermined position at which a clutch torque is transmitted and determining a total torque M of the input shaft of the inactive sub-drive train during a predetermined period P2; Determining the clutch torque M _K of EingangsweIle the inactive part of the drive train of the drag torque M _S and the total torque M as the sum of drag torque M _S and clutch torque M _K ; Determining the Tastpunktposition from the absolute value of the detected clutch torque M _K and the clutch characteristic of the clutch of the inactive part of the drive train to determine the tactile regardless of engine torque, as often as possible, as possible without affecting the shift sequence and without increased wear during operation of the vehicle.

From the German patent application with the file number 10 2011 106 774.8 a method is known for monitoring a clutch, in particular a power shift clutch of a drive train of a motor vehicle, wherein the clutch upstream of an engine output shaft and a transmission input shaft of a transmission of the drive train is followed, are carried out in the following steps: keeping open the clutch of the transmission; Laying out a gear of the gearbox; Determining a spin magnitude indicative of a spin behavior of the transmission input shaft of the transmission; Storing the detected spin magnitude or a derived quantity associated with a name of the transmission and associating the information whether the speed of the transmission input shaft of the transmission is greater or smaller than the speed of the motor output shaft at the time of determining the spin quantity, in a non-volatile memory , For an improved monitoring of a clutch, in particular a power shift clutch, a drive train of a motor vehicle is possible, in particular to identify a state of the drive train and / or the power-shift clutch.

From the German patent application with the file number 10 2011 087 900.5 a method is known for determining a Kupplungstastpunkts a friction clutch in a motor vehicle having a drive unit and a transmission, wherein the friction clutch between the drive unit and the transmission is arranged, wherein from the transmission input shaft speed while driving the motor vehicle, a speed gradient of the transmission input shafts is determined and wherein for determining the speed gradient of the transmission input shaft is checked for linear behavior and is determined upon detection of a linear behavior, the speed gradient of the transmission input shaft to greatly reduce the determination while maintaining the accuracy of the tactile points of the Kupplungstastpunkts.

The invention has for its object to improve a method mentioned above. In particular, a Tastpunktermittlung should be reliably enabled even at very different drag moments of the input shafts. In particular, a possibly repeated, canceling a determination process should be prevented. In particular, a rapid adjustment of a torque offset value should be made possible. In particular, a change in the torque offset value should be limited. In particular, a requirement should be made possible for both positive and negative clutch torques.

The object is achieved by a method for determining a touch point of a friction clutch device with a first friction clutch and a second friction clutch in a motor vehicle, the motor vehicle having an internal combustion engine and a Transmission device, the transmission device comprising a first partial transmission with a first input shaft and a second partial transmission with a second input shaft which can be coupled by means of a friction clutch of the friction clutch device with the internal combustion engine and / or decoupled from the internal combustion engine, wherein initially in a driving operation in one of the Internal combustion engine decoupled partial transmission with gear ratio designed a drag torque of the input shaft determines this sub-transmission, subsequently constructed by using an associated friction clutch based on a clutch torque request, a clutch torque and subsequently from the drag torque and the clutch torque a cumulative torque is formed in which in a determination of the clutch torque request, the clutch torque request is limited. The clutch torque request can be limited to one range. The area may have a lower bound and an upper bound.

The friction clutch device may have at least one actuator for actuation. The friction clutch device may include a first actuator for actuating the first friction clutch and a second actuator for actuating the second friction clutch. The touch point may describe an actuator position in which the respective friction clutch begins to transmit a moment at an operation proceeding from a decoupled actuation position in the direction of a coupling actuation position. The touch point may describe an actuator position in which the respective friction clutch transmits a predetermined moment. The predetermined moment may be, for example, about 2-3 Nm. The friction clutch device may have a control device. The control device can serve to carry out the method according to the invention. The control device may have a memory device. The memory device may comprise a nonvolatile electronic memory whose stored information may be electrically erased or overwritten. The memory device may comprise an EEPROM. An actuator position associated with the touch point may be stored in the memory device. In the present case, the term "touch point" may also designate the actuator position assigned to the touch point. The touch point can be adapted. A touch point adaptation can be used to adapt a calculated touch point to a real touch point. The determination of the touch point can be done within the scope of a touch point adaptation. A touch point adaptation can lead to a touch point shift. A touch point shift may correspond to a parallel shift of a clutch characteristic in which a transmittable torque is applied across a path.

The friction clutches can each be actuated between an open and a closed actuation position. The friction clutches may each have an input part and an output part. In a fully open actuation position, the input part and the output part can each be at least approximately completely decoupled from each other. In a fully closed actuation position, the input part and the output part can each be at least approximately completely coupled to each other. An actuation of a friction clutch in the closing direction can each cause an increasing torque transmission. An actuation of a friction clutch in the opening direction can each cause a decreasing torque transmission.

In the present case, the term "at gear ratio interpreted" an idle or neutral position of the sub-transmission designate. The drag torque of an input shaft can be determined using a speed gradient of the input shaft. The speed gradient may be achieved by slowing down the input shaft from an output speed. The input shaft can be decelerated due to its moment of inertia. The input shaft can be braked due to bearing friction against a transmission housing. To build up a clutch torque, the friction clutch can be actuated in the closing direction. The actuation of the friction clutch can be moment-controlled. The clutch torque request can be used for torque control of the friction clutch. The formation of the cumulative torque can take place with the aid of the control device. The summation torque can be formed by adding the drag torque and the clutch torque.

The method according to the invention allows rapid adaptation while at the same time limiting the change of a torque offset value. A clutch torque request is stabilized. A Tastpunktermittlung is reliably enabled even at very different drag torques of the input shafts. Canceling a discovery process is prevented.

The clutch torque request can be limited dynamically. The clutch torque request can be limited individually. When determining the clutch torque request, the drag torque can be incorporated. When determining the clutch torque request, the current drag torque can be incorporated.

When building the clutch torque, a speed of the input shaft of the decoupled partial transmission to a speed of the other Adjusted input shaft while a speed difference between the input shafts are reduced to a predetermined minimum value.

When determining the clutch torque request, a torque required for a complete adaptation of the rotational speed of the input shaft of the decoupled partial transmission to a rotational speed of the other input shaft can first be determined, subsequently limiting the torque determined in the preceding step to a predetermined torque range, subsequently determined in the preceding step Moment reduced by the summation moment, subsequently limiting the torque determined in the previous step to a predetermined torque range and subsequently reducing the determined in the previous step moment by a predetermined torque offset value. The reduction of the torque by the predetermined torque offset value enables a request of negative moments. The torque offset value serves, in particular, to quickly return a touch point, which causes too much engagement of the friction clutch, to a real touch point.

The moment can be limited to the same torque range in different steps. The torque required for complete adaptation of the rotational speed of the input shaft of the decoupled partial transmission to a rotational speed of the other input shaft and the torque reduced by the cumulative torque can each be limited to the same torque range. The moment can be limited to a fixed torque range or to an individually determined torque range. The torque can be limited to a torque range between about 1 Nm and about 5 Nm, in particular between about 1 Nm and about 3 Nm. The lower limit ensures the demand of one moment.

Before the torque is reduced by the summation torque, the summation torque can be scaled. The sum moment can be scaled by using a fixed factor or by using an individually determined factor. Thus, the moment may be kept within the torque range, if necessary.

At least one value required for determining the drag torque can be stored. The torque required for a complete adaptation of the rotational speed of the input shaft of the decoupled partial transmission to a rotational speed of the other input shaft can be stored. A limit value or bounding area can be stored. The summation moment can be saved. The torque offset value can be stored. A storage can take place in the storage device. Thus, a stored value after switching on an ignition of a motor vehicle immediately available again. A drag torque value can be immediately available again after switching on an ignition of a motor vehicle. It can be realized a kind of feedforward control.

In summary and in other words, the invention thus provides, among other things, a determination of a torque requirement for a touch point adaptation via an evaluation of transmission input rotational speed signals in the case of dual-clutch transmissions during driving operation. Known values for drag torques on input shafts can be included directly in a calculation of a torque to be requested. It can be used for this purpose a total drag torque from the clutch side and the transmission side drag torque.

The calculation of the torque request for the touch point adaptation can take place via the evaluation of the transmission input speeds in several steps. a) Determination of the necessary moment for the reduction of the residual slip. b) Limiting the specific moment from a) to a range of moments. c) reduction of the limited moment from b) by the sum drag torque. d) Limiting the moment from c) to a torque range. e) reduction of the limited moment from d) by the determined torque offset value.

The limitation in point b) and d) can be made with the same limits. For example, 1 Nm can be used as the lower limit and 3 Nm as the upper limit. It should be a minimum requested moment, z. B. 1 Nm, not be exceeded. Starting with a total drag torque of 2 Nm, the minimum torque request can be selected in this example if the upper limit is reached after step b). It may therefore make sense to first scale the drag torque by one factor and then subtract it in point c). Only the reduction of the limited moment in point e) can make it possible to request negative moments. The torque offset value can then only be used to quickly reduce a too high software sample point with the routine to the actual hardware sample point.

Important values for the calculation of the drag torques can be stored in an EEPROM. If the ignition is switched on, the old drag torque can be restored immediately. The use of the Schleppmomentwertes in the calculation of the torque request can represent a kind of feedforward control from a control perspective.

By "may" in particular optional features of the invention are referred to. Accordingly, there is an embodiment of the invention each having the respective feature or features.

Hereinafter, an embodiment of the invention will be described with reference to figures. From this description, further features and advantages. Concrete features of this embodiment may represent general features of the invention. Features associated with other features of this embodiment may also represent individual features of the invention.

They show schematically and by way of example:

1 a block diagram of a dual-clutch transmission with associated electronic control device and

2 a diagram of speed curves during a Tastpunktadaption.

1 shows a block diagram of a dual clutch transmission with associated electronic control device. The dual-clutch or parallel transmission has an example driven by an internal combustion engine drive shaft 6 on, with optional two input shafts 8th and 10 rotatably connected. The torque flow from the drive shaft 6 in the input shafts 8th and 10 is via either a clutch K1 and K2 selectively controllable. Between the input shaft 8th and an output shaft 12 are wheel pairs, of which only one is shown, different translations switchable. Likewise, between the input shaft 10 and the output shaft 12 different wheel pairs switchable, of which only one is shown. To operate the clutches K1 and K2 are actuators 14 and 16 intended. For switching the wheel pairings, for example for establishing a rotationally fixed connection between the on the input shaft 8th or 10 arranged wheel with the respective input shaft 8th or 10 that with a respective, with the output shaft 12 constantly non-rotatably connected wheel combs are actuators 18 and 20 For example, each may include a shift actuator and a select actuator. Overall, the input shaft 8th and the output shaft 12 as well as the input shaft 10 and the output shaft 12 one sub-transmission each 22 respectively. 24 of the dual-clutch transmission.

For controlling the actuators 14 . 16 . 18 and 20 serves an electronic control device 26 with microprocessor and associated program and data memories whose outputs each control one of the actuators and their inputs 28 with sensors 30 . 32 respectively. 34 connected to the speed of the drive shaft 6 , the input shaft 8th and the input shaft 10 detect, and other sensors for detecting operating parameters of the vehicle drive train, such as a sensor for detecting the rotational speed of the driven vehicle wheels, a sensor for detecting the position of a gear selector lever, a sensor for detecting the position of an accelerator pedal, etc. The illustrated control device 26 can be connected via a bus system with other control devices of the vehicle, such as an engine control unit with which a power actuator of the engine is controlled. The actuators can be designed, for example, as lever actuators, which are actuated, for example, by an electric motor, wherein the revolution of each electric motor is detected by an increment counter (not shown).

At the in 1 shown dual-clutch transmission can in the respective partial transmission 22 or 24 whose clutch is open, one gear each are engaged, while the effective transmission ratio of the transmission is determined by that (active) part transmission, whose clutch is closed. When in the partial transmission 22 For example, a gear is engaged and the clutch K1 is closed, then this gear for the ratio between the drive shaft 6 and the output shaft 12 effective. At the same time, in the other partial transmission 24 a new gear to be switched be inserted. When switching the transmission of the currently engaged gear in the newly engaged gear, the clutch K1 must open and, for a traction-free connection between the drive shaft 6 and the output shaft 12 , the clutch K2 be closed overlapping.

For controlling the clutches K1, K2 are in the control device 26 Coupling characteristics saved. There is a transferable moment over a path. A clutch characteristic comprises a touch point of a clutch. The touch point describes an actuator position in which the clutch begins to transmit a torque at an operation starting from a decoupled actuation position in the direction of a coupling actuation position. The touch point describes an actuator position in which the respective friction clutch transmits a predetermined moment. The predetermined moment is a small moment. The predetermined moment is for example about 3 Nm. An actuator position associated with the touch point is stored in the memory device.

In order to bring about an adaptation to changed operating conditions, for example to a changed temperature or to a changed state of wear, the touch point is adapted. A Tastpunktadaption serves to a to adjust the calculated touch point to a real touch point. A touch point adaptation can lead to a touch point shift. A touch point shift causes a parallel displacement of a clutch characteristic.

2 shows a diagram 40 to speed curves during a Tastpunktadaption a clutch, such as clutch K1 and / or K2 according to 1 , The x-axis is a time axis, on the y-axis are speed values 42 the first input shaft, speed values 44 the second input shaft, a switching curve 46 of the first partial transmission, switching characteristics 48 of the second partial transmission and clutch positions 50 one of the second input shaft and the second partial transmission associated clutch applied. The touch point adaptation is performed when the part gear associated with this clutch is inactive.

The touch point adaptation takes place in two phases 52 . 54 , In a first phase 52 is first determined in a driving operation in the inactive second partial transmission with gear ratio designed a drag torque of the second input shaft of this sub-transmission. The drag torque is based on a speed drop 56 the second input shaft determined. The speed drop 56 The second input shaft results in particular due to the moment of inertia and a bearing friction of the second input shaft.

In a second phase 54 For example, clutch torque is established based on a clutch torque request, and a speed is established by operating the associated clutch 44 the second input shaft of the decoupled partial transmission to a speed 42 adapted to the first input shaft. Subsequently, a summation moment is formed from the drag torque and the clutch torque. The clutch torque request is dynamically limited. This results in the second phase 54 a speed drop 58 which is less steep than a speed drop 60 runs without limiting the clutch torque request.

To determine the clutch torque request is first one for a complete adjustment of the speed 44 the input shaft of the decoupled partial transmission to a speed 42 Subsequently, the torque determined in the previous step is limited to a torque range between 1 Nm and 3 Nm. Subsequently, the torque determined in the previous step is reduced by the summation torque from the drag torque and the clutch torque in the previous step, certain torque is limited to a torque range between 1 Nm and 3 Nm, and subsequently the torque determined in the previous step is reduced by a torque offset value. In this case, the values important for determining the clutch torque request are stored.

From the shift history 46 of the first partial transmission and the speed values 42 the first input shaft, it can be seen that in the first partial transmission during the in the diagram 40 shown Tastpunktadaption a translation stage, in this case the 2nd gear, is inserted and an accelerating drive takes place. The switching curves 48 of the second partial transmission show that at the beginning of the first phase 52 a first engaged in the second partial transmission gear ratio, in this case the first gear, designed and switched to an idle. After completion of the Tastpunktadaption a new gear ratio, in this case the third gear, is inserted in the second part of transmission. Based on the coupling positions 50 is apparent as the second part of the transmission and the second input shaft associated clutch at the beginning of the second phase 54 is closed to build up the clutch torque. After completion of the second phase 54 and before inserting the new gear ratio, the clutch is opened again. An engagement of the clutch without limiting the clutch torque request is with 62 designated. An engagement of the clutch with limitation of the clutch torque request is with 64 designated. It can be seen that the limited clutch torque request clutch engages less far than without limited clutch torque demand.

LIST OF REFERENCE NUMBERS

6

 drive shaft

8th

 input shaft

10

 input shaft

12

 output shaft

14

 actuator

16

 actuator

18

 actuator

20

 actuator

22

 subtransmissions

24

 subtransmissions

26

 control device

28

 inputs

30

 sensor

32

 sensor

34

 sensor

K1

 clutch

K2

 clutch

40

 diagram

42

 Speed values

44

 Speed values

46

 switching courses

48

 switching courses

50

 clutch positions

52

 first phase

54

 second phase

56

 Speed drop

58

 Speed drop

60

 Speed drop

62

 Engage the clutch

64

 Engage the clutch

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 102010024941 A1 [0002]
• DE 102011106774 [0003]
• DE 102011087900 [0004]

Claims (9)

Method for determining a contact point of a friction clutch device with a first friction clutch (K1) and a second friction clutch (K2) in a motor vehicle, the motor vehicle having an internal combustion engine and a transmission device, the transmission device having a first partial transmission ( 22 ) with a first input shaft ( 8th ) and a second partial transmission ( 24 ) with a second input shaft ( 10 ), each of which can be coupled to the internal combustion engine by means of a friction clutch (K1, K2) of the friction clutch device and / or decoupled from the internal combustion engine, wherein first in a driving operation in a partial transmission decoupled from the internal combustion engine ( 24 ) with the gear stage designed, a drag torque of the input shaft ( 10 ) of this sub-transmission ( 24 ), then by means of actuation of an associated friction clutch (K2) based on a clutch torque request to build up a clutch torque and subsequently to form a cumulative torque from the drag torque and the clutch torque, characterized in that the clutch torque request is limited in a determination of the clutch torque request. A method according to claim 1, characterized in that the clutch torque request is dynamically limited. Method according to at least one of the preceding claims, characterized in that, during the construction of the clutch torque, a rotational speed ( 44 ) of the input shaft ( 10 ) of the decoupled partial transmission ( 24 ) to a speed ( 42 ) of the other input shaft ( 8th ) and thereby a speed difference between the input shafts ( 8th . 10 ) is reduced to a predetermined minimum value. Method according to at least one of the preceding claims, characterized in that, for a determination of the clutch torque requirement, first one for a complete adaptation of the rotational speed ( 44 ) of the input shaft ( 10 ) of the decoupled partial transmission ( 24 ) to a speed ( 42 ) of the other input shaft ( 8th Subsequently, the torque determined in the previous step is limited to a predetermined torque range, subsequently the torque determined in the previous step is reduced by the summation torque, subsequently the torque determined in the preceding step is limited to a predetermined torque range, and subsequently that in the previous step is reduced by a predetermined torque offset value certain moment. A method according to claim 4, characterized in that the torque is limited in different steps in each case to the same torque range. A method according to claim 5, characterized in that the torque is limited to a fixed predetermined torque range or to an individually determined torque range. Method according to at least one of claims 4-6, characterized in that the summation torque is scaled before the reduction of the moment about the summation moment. A method according to claim 7, characterized in that the summation torque is scaled by means of a fixed predetermined factor or by means of an individually determined factor. Method according to at least one of the preceding claims, characterized in that at least one value required for determining the drag torque is stored.

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