WO2013124122A1

WO2013124122A1 - Method for determining a clutch torque requirement

Info

Publication number: WO2013124122A1
Application number: PCT/EP2013/051578
Authority: WO
Inventors: Erhard Hodrus; Ekkehard Reibold
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2012-02-20
Filing date: 2013-01-28
Publication date: 2013-08-29
Also published as: DE112013001042A5; DE112013001042B4; JP2015513052A; DE102013201317A1; CN104053923B; JP6203201B2; CN104053923A

Abstract

A method for determining a contact point of a friction clutch device comprising a first friction clutch and a second friction clutch in a motor vehicle, said motor vehicle having an internal combustion engine and a transmission, said transmission having a first partial transmission comprising a first input shaft and a second partial transmission comprising a second input shaft, each of which can be coupled to and/or uncoupled from the internal combustion engine by means of a friction clutch of the friction clutch device, wherein in a drive operation a drag torque of the input shaft of a partial transmission is first determined in a partial transmission uncoupled from the internal combustion engine with a disengaged transmission gear, then a clutch torque is built up by means of actuation of a corresponding friction clutch based on a clutch torque requirement and then an overall torque is formed from the drag torque and the clutch torque, wherein the clutch torque requirement is limited when the clutch torque requirement is determined from said overall torque, in order to improve the method.

Description

Method for determining a clutch torque request

The invention relates to a method for determining a touch 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 , 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 determined in a driving operation in a decoupled from the engine part transmission with gear ratio geared a drag torque of the input shaft of this sub-transmission, 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 DE 10 2010 024 941 A1 a method is known for controlling a dual-clutch transmission with at least two partial drive trains, each of which can be coupled by means of a clutch to an internal combustion engine, in which the following steps are carried out on the inactive part drive train: change with the clutch disengaged inlaid gear in neutral; Determining the drag torque M _{s of} the input shaft of the inactive sub-drive train during a predetermined period of time 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} the input shaft of the inactive part of the drive train from 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 10 201 1 106 774.8 a method for monitoring a clutch, in particular a power shift clutch is known a drivetrain 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, in which the following steps are performed: 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 10 201 1 087 900.5 a method is known for determining a Kupplungstastpunkts a friction clutch in a motor vehicle with 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 When driving the motor vehicle, a speed gradient of the transmission input shafts is determined and wherein the determined speed gradient is used to determine the Kupplungstastpunkts, in which the speed curve of the transmission input shaft is checked for linear behavior and determination of a linear behavior, the speed gradient of the transmission input shaft is determined by the To shorten determination significantly while maintaining the accuracy of the touch points.

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 contact 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. ne 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 a deceleration torque of the input shaft of this sub-transmission determined by an actuation of an associated friction clutch based on a clutch torque request and subsequently formed from the drag torque and the clutch torque a cumulative moment 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 can 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" can also be used to designate the actuator position assigned to the touch point 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 designation "gear ratio shifted" may indicate an idle or neutral position of the sub-transmission In this case, the input shaft can be braked against a transmission housing due to bearing friction. The cumulative torque can be generated 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 adapted to a speed of the other input shaft while a speed difference between the input shafts are reduced to a predetermined minimum value.

In a determination of 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. In particular, the torque offset value serves 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 moment 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 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. That for a complete adjustment of the speed of the input shaft of the decoupled th partial gear to a speed of the other input shaft required torque 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. For this purpose, a cumulative drag torque from the clutch-side and the transmission-side drag torque can be used.

The calculation of the torque request for the Tastpunktadaption can over the

Evaluation of the transmission input speeds takes place in several steps, a) determination of the necessary torque for the reduction of the residual slip, b) limitation of the specific torque from a) to a torque range, c) reduction of the limited torque from b) by the total drag torque. d) limitation of the moment from c) to a torque range, e) reduction of the limited torque 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.

In particular, optional features of the invention are referred to as "may." 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:

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

Fig. 2 is a diagram of speed curves during a Tastpunktadaption.

Fig. 1 shows a block diagram of a dual-clutch transmission with associated electronic control device. The Doppelkupplungs- or parallel gearbox has an example driven by an internal combustion engine drive shaft 6, which is selectively rotatably connected to two input shafts 8 and 10. The torque flow from the drive shaft 6 in the input shafts 8 and 10 is selectively controllable via a respective clutch K1 and K2. Between the input shaft 8 and an output shaft 12, different ratios are switchable via pairs of wheels, of which only one is shown. Likewise, 12 different wheel pairs are switchable between the input shaft 10 and the output shaft, of which only one is shown. To actuate the clutches K1 and K2 actuators 14 and 16 are provided. For switching the wheel pairings, for example, for establishing a rotationally fixed connection between the arranged on the input shaft 8 or 10 wheel with the respective input shaft 8 or 10, with a respective, with the Output shaft 12 constantly connected rotatably connected wheel, actuators 18 and 20 are provided, for example, each may include a shift actuator and a Wählaktuator. Overall, the input shaft 8 and the output shaft 12 and the input shaft 10 and the output shaft 12 each form a partial transmission 22 and 24 of the dual-clutch transmission.

To control the actuators 14, 16, 18 and 20 is an electronic control device 26 with microprocessor and associated program and data storage, whose outputs each one of the actuators drive and whose inputs 28 are connected to sensors 30, 32 and 34, respectively, the speed the drive shaft 6, the input shaft 8 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 Accelerators, etc. The illustrated controller 26 may 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).

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

To control the clutches K1, K2 26 clutch characteristics are stored in the control device. 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 is disengaged at a decoupled actuation position. Henden operation in the direction of a coupling operating position begins to transmit a moment. 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 nos. An actuator position assigned to 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 touch point adaptation serves to adapt a 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 of speed curves during a touch point adaptation of a clutch, such as clutch K1 and / or K2 according to FIG. 1. The x-axis is a time axis, on the y-axis are rotational speed values 42 of the first input shaft, rotational speed values 44 second input shaft, a shift curve 46 of the first sub-transmission, switching curves 48 of the second sub-transmission and clutch positions 50 of a second input shaft and the second sub-transmission associated clutch applied. The touch point adaptation is performed when the part gear associated with this clutch is inactive.

The Tastpunktadaption takes place in two phases 52, 54. In a first phase 52, a drag torque of the second input shaft of this sub-transmission is first determined in a driving operation in the inactive second partial transmission with gear ratio designed. The drag torque is determined based on a speed drop 56 of the second input shaft. The speed drop 56 of 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, a clutch torque is established by means of an actuation of the associated clutch based on a clutch torque request and a speed 44 of the second input shaft of the decoupled partial transmission is adapted to a speed 42 of 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 without limiting the clutch torque request. To determine the clutch torque request, a torque required for a complete adaptation of the speed 44 of the input shaft of the decoupled partial transmission to a speed 42 of the other input shaft is first determined, subsequently the torque determined in the preceding 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 cumulative torque from the drag torque and the clutch torque, subsequently, the torque determined in the previous step is limited to a torque range between 1 Nm and 3 Nm, and subsequently the torque determined in the previous step is reversed reduces a torque offset value. In this case, the values important for determining the clutch torque request are stored.

From the shift curve 46 of the first partial transmission and the rotational speed values 42 of the first input shaft it can be seen that in the first partial transmission during the Tastpunktadaption shown in the diagram 40, a gear ratio, in this case the 2nd gear is engaged and an accelerating drive. The shift profiles 48 of the second partial transmission show that at the beginning of the first phase 52, a transmission stage initially engaged in the second partial transmission, in the present case of FIG. 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. The clutch positions 50 show how the clutch associated with the second partial transmission and the second input shaft is closed at the beginning of the second phase 54 in order 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. Engagement of the clutch without limiting the clutch torque requirement is indicated at 62. An engagement of the clutch with limitation of the clutch torque requirement is designated 64. It can be seen that the limited clutch torque request clutch engages less far than without limited clutch torque demand. List of accessories Drive shaft

input shaft

10 input shaft

12 output shaft

14 actuator

16 actuator

18 actuator

0 actuator

2 partial transmissions

4 partial transmissions

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 curves

48 switching curves

50 coupling positions

52 first phase

54 second phase

56 speed drop

58 speed drop

60 speed drop

62 Engage the clutch

64 Engage the clutch

Claims

claims

1 . Method for determining a contact point of a friction clutch device having 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 (8) 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 initially in a driving operation in one of the internal combustion engine decoupled partial transmission (24) determines a drag torque of the input shaft (10) of this sub-transmission (24), then by means of an operation of an associated friction clutch (K2) constructed and nachfo a clutch torque based on a Kupplungsmomentenanfor- tion a momentum torque is formed from the drag torque and the clutch torque, characterized in that the Kupplungsmomentenan- request is limited in a determination of the clutch torque request.

2. The method according to claim 1, characterized in that the clutch torque request is dynamically limited.

3. The method according to at least one of the preceding claims, characterized in that during the construction of the clutch torque, a speed (44) of the input shaft (10) of the decoupled partial transmission (24) adapted to a speed (42) of the other input shaft (8) and a Speed difference between the input shafts (8, 10) is reduced to a predetermined minimum value.

4. The method according to at least one of the preceding claims, characterized in that in a determination of the clutch torque request first for a complete adjustment of the rotational speed (44) of the input shaft (10) of the decoupled partial transmission (24) to a rotational speed (42) of the other input shaft (8) determines the required torque, subsequently limiting the torque determined in the previous step to a predetermined torque range, subsequently reducing the torque determined in the preceding step by the summation torque, subsequently limiting the torque determined in the preceding step to a predetermined torque range and subsequently in the previous step, certain moment is reduced by a predetermined torque offset value.

5. The method according to claim 4, characterized in that the torque is limited in different steps in each case to the same torque range.

6. The 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.

7. The method according to least one of claims 4-6, characterized in that before the reduction of the moment to the summation moment the summation torque is scaled.

8. The method according to claim 7, characterized in that the summation moment is scaled by means of a fixed predetermined factor or by means of an individually determined factor.

9. 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.