WO1999001312A1

WO1999001312A1 - Method and device for controlling a clutch

Info

Publication number: WO1999001312A1
Application number: PCT/DE1998/001904
Authority: WO
Inventors: Klaus KÜPPER
Original assignee: Luk Getriebe-Systeme Gmbh
Priority date: 1997-07-05
Filing date: 1998-07-03
Publication date: 1999-01-14
Also published as: FR2765644B1; GB2331792B; BR9806019A; DE19829835A1; DE19880849D2; FR2765644A1; AU9251698A; GB9904327D0; GB2331792A; KR20000068477A

Abstract

The invention relates to a method for controlling the operation of a clutch positioned between a drive engine and a manual gear mechanism in the power train of a motor vehicle. According to said method, any actuation of the gear lever of the gear mechanism is detected and, if certain requirements are met, identified as an intention to change gears, after which the clutch is opened if an intention to change gears has been identified. The conditions determining identification of an intention to change gears are modified when such an intention to change gears is identified for longer than a predetermined period or if more than a predetermined number of intentions to change gears is identified during a predetermined period or if the motor vehicle is travelling on a poor road which results in relative movements between the gear lever and gear mechanism or if a play between the gear lever and gear elements within the gear mechanism changes.

Description

Method and device for controlling a clutch

The invention relates to a method and a device for controlling the operation of an automated clutch arranged in the drive train of a vehicle with a drive motor and a transmission.

The automation of clutches in connection with manual transmissions is becoming increasingly popular. Coupling automation not only increases the ease of use of a vehicle; it is also a means of reducing fuel consumption, since it encourages shifting more frequently and thus driving more frequently in the most fuel-efficient gear. An automatically actuated clutch is also advantageous in automated manual transmissions, in which manual transmissions can be actuated automatically by a controllable actuator.

In the case of an clutch that can be actuated automatically, a shift request of the driver must be recognized in order to open the clutch and thereby facilitate the gear change or even make it possible in the first place. A sensor detects the driver's shift request, for example by a sensor in / on the manual shift lever or transmission, and the control unit of the automated system processes this signal and generates a shift intention signal, whereupon the clutch is disengaged, for example, when changing gear. If there is a malfunction with this switching intention, specifically unintentional opening of the clutch, this can have various negative consequences. This includes loss of comfort, high clutch loads, increased loads on the clutch actuator, etc.

The invention is based on the object of further developing a method of the type described at the outset in such a way that a switching intention is reliably detected in each case. It is also part of the task to recognize an intention to shift when there is a driver-side shift request by actuating an element and also to recognize that there is no intention to shift when this signal is not present. The invention is further based on the object of providing an apparatus for carrying out the method according to the invention.

The subordinate claims 1, 2, 12 and 15 are directed to solutions of the part of the object of the invention relating to the method.

With the features of claim 1 it is achieved that a permanent or unusually long actuation of the shift lever or a supposed actuation of the shift lever, for example because of play of the shift lever in the external circuit, which normally leads to a corresponding intention to identify the shift, is determined, which then leads to suppression of the intention to switch. With the features of claim 2 it is achieved that an unusually rapid succession of identifications of a shift intention, which can be attributed to operating errors or, for example, vibrations in the drive train or signal disturbances that are transmitted to the shift lever, is detected and leads to a suppression of the shift intention .

With the features of claim 3 it is achieved that the shift intention suppression can be adapted in an advantageous manner to the respective operating conditions of the vehicle and / or the drive train, for example to the gear engaged in each case, to the driving speed, to the actuation of the brake, engine speed, transmission speed etc..

Claims 4 to 11 are directed to advantageous examples of changing the conditions for identifying a switching intention.

With the features of claim 12, possible influences on the identification of a shift intention are suppressed by a poor road condition.

According to claims 13 or 14, it is advantageous to increase threshold values, the exceeding of which is a prerequisite for the identification of a shift intention, ie to make the shift intention detection less sensitive. With the features of claim 15 it is achieved that games in the transmission path from the shift lever to the shift members in the transmission are taken into account and are not incorrectly identified as an intention to shift.

Claims 16, 17 and 18 are each directed to an exemplary embodiment of a method according to the invention which is particularly advantageous in practice.

The claim 19 characterizes the basic structure of a device for performing the method according to the invention. Claims 20 and 21 represent advantageous embodiments.

The invention is explained below with reference to schematic drawings, for example and with further details.

They represent:

1 is a block diagram of a motor vehicle equipped with an automated clutch and manual transmission; FIG. 2 shows some details of the shift actuation according to FIGS. 1, 3 and 4

Graphics for explaining two implementation examples of methods according to the invention and FIG. 5 an arrangement of a transmission with an actuating element, such as a shift lever. 1, a motor vehicle has an internal combustion engine 2 serving as a drive motor, which is connected via a clutch 4 to a manual transmission 6. A gear lever or shift lever 7 is used to shift the manual transmission 6. The driven wheels, such as the rear wheels 12 or the front wheels or both rear and front wheels, are driven from the manual transmission 6 via a propeller shaft 8 and a differential 10. A braking system 14 with a braking device 16, which is actuated via a brake pedal 18, is used to brake the motor vehicle. All wheel brakes are preferably actuated from the braking device 16, only the line to the left front wheel being shown.

An accelerator pedal 20 is used to control the load of the internal combustion engine 2, the position of which is detected by a position transmitter 21 and is fed to a control unit 22. An actuator 23 for actuating a throttle valve 24 is controlled by the control unit.

The clutch 4 is automated and is actuated by an actuator 25 via a master cylinder 27 and a slave cylinder 29. The actuator 25 is controlled by the control unit 21, which contains a microprocessor with associated memories in a manner known per se and whose inputs are connected to various sensors of the drive train, for example a sensor 32 for the speed of the internal combustion engine, a sensor 34 for the wheel speed, a sensor 36 for detecting the position of the shift lever 7, a sensor 37 for detecting the shift lever actuation, a sensor for detecting the position of the clutch 4, a sensor 40 for the position of the actuator 25, a sensor 42 for detecting the cooling water temperature, a sensor 44 for detecting the temperature of the intake air and, if appropriate, others Sensors. The sensors or the electronic units can also transmit the sensor signals to the control unit via a data bus, such as a CAN bus.

The slave cylinder 29 interacts directly with a clutch lever 48 or indirectly via a linkage which is urged into its rest position by a clutch return spring, not shown, such as a plate spring, in which the clutch 4 is fully closed, i.e. can transmit their maximum moment.

The function of the various arrangements is such that when the switching lever 7 is actuated, which is detected by means of the sensors 36 and / or 37 or further sensors arranged inside / outside the transmission 6, the control unit 22 is stored / implemented in it as software or hardware Algorithms determine whether the shift lever operation expresses a driver's request or not. When a shift request is identified, the actuator 25 is activated by the control unit 22, so that the clutch 4 opens. At the same time, the actuator 23 for the throttle valve 24 can be actuated in such a way that the throttle valve 24 closes during the switching operation, despite the accelerator pedal 20 being actuated. Is the control unit 22 based on the Sensor 36 and / or other sensors within the manual transmission 6 detected that a shift is complete, the clutch is closed and the throttle valve 24 assumes the position corresponding to the position of the accelerator pedal 20. A pedal value transmitter of the accelerator pedal and / or a brake light switch which detects the actuation of a brake can also be used.

The control unit for controlling the automated clutch actuation can be in signal connection with other control units. These control units can exchange data, for example, via a data bus. Such signals can be data about the state of the road, for example.

The shift lever 7 actuates indirectly via a linkage or a Bowden cable or directly via transmission elements a shift shaft 52 which is arranged within the transmission and can be moved axially back and forth and pivoted. The axial back and forth movement of the control shaft 52 corresponds to a selection movement; the pivoting movement corresponds to a switching movement. The selector shaft 52 has a selector finger 54 which protrudes into selector forks 56 which are mounted on the transmission housing in a linearly displaceable manner and can be moved back and forth between two end positions, each end position corresponding to the shifting of a gear. The end position of the shift forks 56 are detected by microswitches 58, of which only the right-hand side is shown in FIG. 2. The selection movement of the switching shaft 52 is detected by a sensor 60 and the switching movement by a sensor 62. The sensor configuration of the gearbox can vary greatly depending on the requirements and the sensors selected. For example, the sensor 37 provided directly in the knob of the shift lever 7 according to FIG. 1, which can respond to a mere touch and / or can detect the actuating force, can be completely omitted and replaced by one or more sensors, for example sensors 60 and 62, which detect the movement of the shift lever 7 or the shift shaft 52, wherein a signal can be derived from the movement signal which indicates the actuation speed of the shift lever 7 or the shift shaft 52.

As already explained at the beginning, reliable shift intention detection is a prerequisite for the correct actuation of the clutch 4. It is in the nature of things that the shift intention detection is only active for the short time of changing gear. As soon as a gear is removed (recognizable by the signal from the microswitches 58 and / or the signal from the sensor 62) or the driver changes his intention to shift, ie leaves the old gear, the intention to shift no longer responds. Since the clutch does not close as long as a shift intention is recognized, it is expedient to change the conditions for identifying a shift intention within the control device if a shift intention is identified continuously beyond a predetermined period of time. The long duration of an intention to shift can be caused by an error in one of the sensors or also in the control unit or by the driver, for example, not switching the shift lever after performing a shift releases and is identified as an intention to shift when a force exerted on the knob of the shift lever exceeds a predetermined value. The period of time that leads to a change in the shift intention can be constant, it can be selected differently from gear to gear and depending on the driving situation. It is advantageous to choose a short period of time for high load requirements by the driver and, for example, to extend it in overrun mode, since experience has shown that the shift lever is actuated very slowly in overrun mode.

The consequences of an intention to switch beyond the predetermined period of time can be different. On the one hand, the intention to switch can be deleted if their identification continues beyond the predetermined period of time. On the other hand, a threshold value, for example the level of force with which the shift lever 7 has to be actuated in order to trigger an intention to shift, can be increased in order in this way to prevent or stop the triggering.

3 shows an example of how the threshold S, the exceeding of which leads to the triggering of a switching intention, can be changed dynamically, t indicates the time. The curve drawn shows how the initially low threshold is gradually increased until it is greater than the actuating force at time 1, so that the intention to switch is deleted. From time 2, the threshold is gradually lowered in order to remain at the setpoint shown in dashed lines. The associated adaptation methods or programs are stored in the control unit 22. Another problem with shift intention identification is as follows:

For example, if a driver changes his intention to shift, i.e. If he first actuates the shift lever with a predetermined force or by a predetermined distance so that he does not shift after all, and even does this in repeated alternation, this may lead to a brief intention to shift with the associated opening of the clutch. In order to suppress those states which lead to a rapid change between shift intention identification and no existing shift intention, it is advantageous to change the conditions for identifying a shift intention if more than a predetermined number of shift intentions have been identified within a predetermined period of time. The change in the conditions can consist, for example, in that after identifying closely sequential switching intentions, the switching intent is deleted over a predetermined period of time. It is also possible to monitor the path of the shift lever or another element of the circuit, for example the shift shaft 52, and to suppress a shift intention identification if a certain path has been traveled after (or before) the shift intention.

One possibility that can lead to incorrect shift intention identification is driving on bad or uneven roads, which lead, for example, to natural vibrations of shift lever 7, which can be incorrectly identified as shift intention. To rule out such errors, For example, driving on bad roads can be sensed by detecting movement amplitudes and frequencies of the bearing in a bearing (not shown) of the motor / transmission unit on the chassis and supplying them to the control unit 22 as corresponding signals. In control unit 22, threshold values can then be raised and lowered again in accordance with the roadway signals, the threshold values of which are necessary to identify a shift intention, these threshold values being able to be briefly increased to such an extent that a shift intention is not recognized at all. In this way, incorrect identifications of a switching intention can be avoided. It goes without saying that the increase in threshold value can depend on the strength of the strength of the disturbances caused by the road. Furthermore, individual impacts, for example through potholes or thresholds on the road, can be detected in order to make it more difficult to identify the gearshift intention for the short period of time when such faults occur and their after-effects.

The detection of a bad road surface is possible in a variety of ways, for example, as described, by sensors on the bearings of the motor / gear unit on the chassis, or by detecting the relative movements of the wheels to the body, by evaluating irregularities in the wheel speed signals, etc.

A strategy shown in FIG. 4 has proven itself in practice as a criterion for the detection of the switching intent. The path SW that the Shift lever moves, and the speed SG at which the shift lever is operated. The switching lifting speed SG can be obtained, for example, by differentiating the signals from displacement sensors. As can be seen, a longer switching path is required at low switching speeds in order to detect an intention to switch. With increasing actuation speed of the shift lever, the shift lever travel SW approaches asymptotically a straight line O drawn in dashed lines, which indicates an offset value for the shift lever travel which must be exceeded in any case so that an intention to shift is detected or is assessed as being present. In order to rule out incorrect identification of a shift request, the offset value O must in any case be greater than the play that the shift lever has with respect to the shift forks 56 (FIG. 2), for example on poor roads or as a result of the motor / transmission unit moving suddenly when strong Torques or fluctuations in the torque can move this distance, without this being accompanied by an intention to shift initiated by the driver.

There are different ways of determining the game that can change during operation:

For example, the neutral positions can be sensed using the sensor 62 (FIG. 2) and their maximum and minimum values can be detected. The difference between the two sizes is a measure of the play of the external circuit, ie in the transmission path between the shift lever 7 and the shift forks 56 It goes without saying that the neutral position is sensed, for example by means of the sensor 62, only when the switching state N for a predeterminable period of time

Δtj exists, which can be recognized by the sensor 60. The sensed maximum

and minimum values are stored as adaptive parameters in the control unit 22 and used in suitable operating phases for adapting the offset value O (FIG. 4). The entire curve drawn through in FIG. 4 thus shifts upwards with increasing play, that is to say with increasing offset O. The difference between the maximum and minimum values essentially corresponds to the game, taking into account any factors or summands that can be specified. If the game changes during operation, the difference between the above signals changes. As a result, the control unit can bind the offset value O to the changed difference by always taking an additional summand and / or factor into account.

O = factor ^* (maximum value - minimum value) + summand

As a further solution according to the invention it can be provided that the disengagement thresholds of the intention to shift are detected by a differential path method, as the differential path between the sensors 104 and 120 of FIG. 5, during operation of the device according to the invention. Decoupling thresholds are considered to be variables that occur during a shift process from the maximum expansion or difference between the sensor data of sensors 104 and 120, that is to say on the transmission and on the shift lever. This determined the maximum difference path during of a switching process can then be converted into a disengagement threshold or processed. These disengagement thresholds can be the same for gear groups such as 1, 3, 5 gear and 2, 4 and R gear or they can be different for all gears. The changes in the disengagement thresholds in the operation of the device according to the invention are detected and used as a measure for the change in play or the elasticity in the external circuit. The value O of the offset can be adjusted by changing the external circuit.

Furthermore, to adapt the value O, the expansion of the external circuit, and thus the difference between sensors 104 and 120, can be detected in a predeterminable range, such as the neutral range, and an increase in this expansion, such as difference, can be used to increase the value O. .

FIG. 5 shows an arrangement 100 of a transmission 101 with a central shift shaft 102, which is operatively connected to shift elements 103 inside the transmission. The gears within the transmission 101 are shifted by the axial and / or rotary movement of the central shift shaft 102. The axial movement of the central switching shaft 102 is detected by the sensor 104, the rotational movement of the central switching shaft 102 being detected by the sensor 105. The sensors are connected to the central control shaft via levers and connecting elements 106, 107, such as rods. The actuation or position of the central control shaft 102 can be detected by the deflection of the sensor elements. The shift lever 110 is connected to the central shift shaft via the connection 111, 112 and 113, such as a linkage or Bowden cable. The central shift shaft 102 is rotated about its axis by a pivoting movement of the shift lever. The shift shaft is actuated in the axial direction by the longitudinal movement of the shift lever. The longitudinal movement takes place essentially along the shift lanes to reach the gear positions or the neutral position. The swivel movement takes place to select the shift gates. In this regard, the shift gate 119 is shown. The shift gate is shown for example for a transmission with five forward gears and one reverse gear. Another gear can also be used. The sensor 120 detects the longitudinal movement of the shift lever. At least some of the sensors 104, 105 and 120 can be designed as potentiometers, Hall sensors and / or other sensors.

By moving the shift lever 110, an intention to shift can be detected by means of the sensor 120. Likewise, a difference path between the sensors 104 and 120 can be detected if the mechanical section 111, 113a, 113b, 102 between the sensors 104, 120 has a predeterminable elasticity and this section is compressed or stretched when the shift lever 110 is actuated. If the detected difference exceeds or falls below a threshold value, an intention to switch is recognized. Instead of a rotatable or rotatable central shift shaft, the transmission shown in FIG. 5 can also have more than one shift shaft, which are rotatable or axially displaceable.

If an error message occurs that is generated by faulty sensor signals from the control unit, it is possible, for example, to switch to another program branch or to an emergency program or replacement strategy, as a result of which the switching intention detection used can be changed. For example, different methods can be used and / or threshold values can be changed. The intention to shift can be deleted until the neutral transmission range is detected. The shift intention thresholds can be corrected or changed individually for each gear or jointly for groups of gear. The change can depend on at least one vehicle operating parameter, how it can be increased or reduced.

The patent claims submitted with the application are proposals for formulation without prejudice for the achievement of further patent protection. The applicant reserves the right to claim further features previously only disclosed in the description and / or drawings.

Back-references used in subclaims indicate the further development of the subject matter of the main claim by the features of the respective subclaim; they are not to be understood as a waiver of the achievement of an independent, objective protection for the characteristics of the subordinate claims. However, the subjects of these subclaims also form independent inventions which have a design which is independent of the subjects of the preceding subclaims.

The invention is also not limited to the exemplary embodiment (s) of the description. Rather, numerous changes and modifications are possible within the scope of the invention, in particular those variants, elements and combinations and / or materials which, for example, by combining or modifying individuals in conjunction with and described in the general description and embodiments and the claims Features or elements or process steps contained in the drawings are inventive and, by means of combinable features, lead to a new object or to new process steps or process step sequences, also insofar as they relate to manufacturing, testing and working processes.

Claims

claims

1. A method for controlling the operation of a clutch arranged in the drive train of a motor vehicle with a drive motor and a manual transmission, in which method an actuation of a

Control element, such as the shift lever of the transmission, is detected by means of at least one sensor, is identified as a shift intention when certain conditions of the sensor signals are met and the clutch is opened when a shift intention is identified, characterized in that the conditions for identifying a

Switching intent can be changed if a switching intent is identified over a predetermined period of time.

2. A method for controlling the operation of a clutch arranged in the drive train of a motor vehicle, a drive motor and a manual transmission, in which method an actuation of an operating element, such as a shift lever of the transmission, is detected by means of at least one sensor when certain conditions of the sensor signals are met as the intention to shift is identified and the clutch is opened upon identification of a shift intention, characterized in that the conditions for identifying a shift intention are changed if more than a predetermined number of shift intentions have been identified within a predetermined period of time.

3. The method according to claim 1 or 2, characterized in that the conditions for identifying a shift intention are changed depending on the operating state of the drive train or the vehicle.

4. The method according to claim 3, characterized in that the predetermined period and / or the predetermined number is a function of the gear engaged in the transmission.

5. The method according to claim 4, characterized in that the predetermined period and / or the predetermined number for each gear, such as forward gear and / or reverse gear, is the same.

6. The method according to claim 4, characterized in that the predetermined period and / or the predetermined number for each

Gear, such as forward gear and / or reverse gear, is different.

7. The method according to claim 4, characterized in that the predetermined time period and / or the predetermined number for groups of gears is different.

8. The method according to claim 1, characterized in that the predetermined

Time period with high load of the drive motor is shorter than in overrun mode and / or the predetermined number at high engine load is less than in overrun mode.

9. The method according to claim 1, characterized in that the switching intention is deleted if their identification continues beyond the predetermined period of time.

10. The method according to claim 1, characterized in that the switching intention is deleted if its identification is present in a predeterminable time period beyond a predeterminable number.

11. The method according to claim 10, characterized in that the switching intention is deleted if a predeterminable number of switching intention signals in the range from 2 to 30 are present within a period of 0.2 s to 3 s, preferably in the period from .5 s to 1.5 s 3 until 10

Signals.

12. A method for controlling the operation of a clutch arranged in the drive train of a motor vehicle with a drive motor and a manual transmission, in which method an actuation of a

Control element, such as the shift lever of the transmission, is detected by means of at least one sensor, is identified as a shift intention when certain conditions of sensor signals are met, and the clutch is opened when a shift intention is identified, thereby characterized in that the conditions for identifying a shift intention on uneven road driven by the vehicle are changed in such a way that relative movements excited by the road between the shift lever and the transmission are at least partially suppressed when the shift intention is identified.

13. The method according to at least one of claims 1 to 12, characterized in that a threshold value of the actuation of the control element, the exceeding of which is a condition for the identification of a switching intention, is increased.

14. The method according to claim 13, characterized in that the threshold value is an actuation path or an actuation force or a differential path when actuating the control element.

15. A method for controlling the operation of a clutch arranged in the drive train of a motor vehicle with a drive motor and a manual transmission, in which method an actuation of the shift lever of the transmission is detected by means of at least one sensor when certain conditions of sensor signals are met

Shift intention is identified and the clutch is opened upon identification of a shift intention, characterized in that the actuation path of the control element, such as shift lever, and a game between the control element and switching elements can be detected within the transmission.

16. The method according to claim 15, characterized in that when a game is recognized, a switching intention is only identified if the detected actuation path is greater than the game.

17. The method according to claim 15 or 16, characterized in that in addition the actuation speed of the control element, such as the shift lever, is detected and that an intention to shift is identified when the actuation path is above a threshold value.

18. The method according to claim 17, characterized in that the threshold value increases with increasing actuation speed.

19. Device for controlling the operation of a clutch arranged between a drive motor and a manual transmission in the drive train of a motor vehicle, comprising an actuator, actuated by a control unit, for actuating the clutch, at least one

Sensor for detecting an actuation of a shift lever that switches the transmission, and a microprocessor contained in the control unit for evaluating the sensor signals and for identifying a shift request if the sensor signals predetermined, in one Program memory stored conditions meet, the microprocessor generates a control signal for controlling the actuator of the clutch when an identified shift request, and with a device for changing the conditions stored in the program memory to identify a shift request according to an im

Program memory stored change program.

20. The apparatus according to claim 19, characterized in that for checking the fulfillment of the sensor signals predetermined conditions, a comparison between actual values of sensor signals with setpoints stored in a memory.

21. The apparatus according to claim 19, characterized in that in order to check whether certain conditions are met, actual values previously processed by the control unit from sensor signals to control signals are compared with target values.