WO2012065587A2

WO2012065587A2 - Detecting the interference behavior of a dual clutch system

Info

Publication number: WO2012065587A2
Application number: PCT/DE2011/001871
Authority: WO
Inventors: Erhard Hodrus
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2010-11-18
Filing date: 2011-10-20
Publication date: 2012-05-24
Also published as: WO2012065587A3; DE112011103807B4; CN103210230A; CN103210230B; DE102011084833A1; WO2012065587A8; DE112011103807A5

Abstract

Method for detecting an interference behavior of a dual clutch system in a dual clutch transmission in the drive train of a motor vehicle comprising a drive unit.

Description

Determination of the cross-talk behavior of a dual-clutch system

The invention relates to a method with the features according to the preamble of

Claim 1.

In dual-clutch systems, the adhesion between the engine and the wheel is realized by two parallel paths, each consisting of a clutch and a partial transmission. The paths are merged towards the wheel via the differential. An example of a known dual clutch system is shown in FIG.

The crosstalk behavior has an influence

- Overlaps during the change of the power flow from one part to the other and to the

- Tactile point determination via evaluation of the transmission input speeds.

Influence of crosstalk behavior in case of overlapping during the change of the power flow from one partial transmission to the other:

In the various driving situations, a clutch is predominantly closed, wherein a gear is engaged on the associated partial transmission. If you change the adhesion from one part of the transmission to the other, e.g. is engaged in the 1st gear part of the 1st gear and driven with the clutch closed and the 2nd gear is preselected in the partial transmission 2, so. the clutch 1 is opened in a ramp and the clutch 2 on the partial transmission 2 is closed ramp-shaped.

In this so-called overlap, both clutch torques ideally result in the applied engine torque. However, even small deviations in a clutch model in comparison to the real system can lead to torque peaks or torque holes, which can severely disturb the ride comfort by virtue of a rattle perceived by the driver.

Investigations have shown that the crosstalk behavior of the couplings has a non-negligible influence, since the touch point of the other clutch and thus

| Confirmation copy | the clutch model changes significantly. At the beginning of a crossover circuit, one clutch is very far closed, while the other clutch is being closed. According to current findings, the clutch to be closed transmits more and more momentum than expected, which in total would lead to an increase in torque. When the clutch is fully closed, one must expect a not insignificant touch point shift of 1-2 mm on the other clutch.

Influence of the crosstalk behavior in the Tactile Point Determination by evaluation of the transmission speeds:

The special arrangement with two parallel paths in a dual-clutch transmission ^" permits the determination of the touch points via the evaluation of the transmission input speeds, such as disclosed in German patent application DE 10 20 0 024 941.6 designed the other part of the transmission gear and the clutch is open. ^'By observation of the speed curve of the transmission input shaft, in a first phase, it is concluded that a drag torque. Later, in a second phase, during closing of the clutch to a small torque is applied to a clutch torque By comparing the requested and actually achieved clutch torque of the touch point and thus the model can be determined on the inactive coupling while driving and thus adapted.

Is the crosstalk behavior of the couplings in the Tastpunktermittelung on the

Evaluation of the transmission input speeds not observed in current building conditions, then the touch point can not be determined in sufficient accuracy.

Model of crosstalk behavior:

It has become known to compensate for the crosstalk behavior, for example, as follows. The following dependency of the current clutch position ^{x is} used in order to torque over the clutch characteristic f

M = f (x) _m to determine. Depending on the index of the coupling results in the process

ST, = + _t x ₂ + bx]

For the two clutches, therefore, the parameters ^α · and with ' ^{e must} be determined; become.

Determination of model parameters on a commissioning test bench:

It has already been proposed the parameters' and the crosstalk model for each. Determine the coupling at the end of the belt on a geared operation test bench and place it in the E Prom memory of the control unit for further use.

For example, the routine closes the active clutch on the transmission test bench to a low torque, in which the most stable clutch torque is transmitted. The test bench sets a previously defined slip between the drive and driven side of the clutch, which is stabilized by a control. A gear is engaged in the active sub-transmission, while Neutral is preselected in the inactive sub-transmission. The routine closes the inactive clutch on this transmission with a position ramp and then opens it again. The moment that is transmitted via the active clutch changes when the inactive clutch is actuated.

From the course of the measured torque can then be the parameters for the

Determine crosstalk model for each clutch.

The determination of the model parameters on the commissioning test stand serves the purpose of

To learn parameters before the first operation. After the clutch has been installed in the bell housing, this determination can only be made once on the transmission test bench. A later repeated determination of the parameters is not possible without a transmission test bench.

If only the dual-clutch system without gearbox is replaced in the workshop during servicing, the oversight behavior must also be determined for this clutch system. For an implementation in the controller, the polynomial representation of the crosstalk is in some cases inappropriate. The representation as characteristic curve or characteristic field allows more complex forms.

The present invention is now based on the object to propose a method which the determination of parameters for a crosstalk model for both clutches of. Dual clutch, for example, by the clutch control software in the vehicle without the aid of a transmission dynamometer allowed.

The object is achieved by a method having the features according to claim 1.

According to the invention, a method for determining the crosstalk behavior of a

Dual clutch system proposed in a dual clutch transmission in the drive train of a motor vehicle having a drive unit, wherein the dual clutch transmission comprises two partial transmissions, each partial transmission is assigned a respective friction clutch of the dual clutch system, which is arranged between a respective partial transmission and the drive unit. According to the invention, it is provided that in a first, the active part transmission a gear is preselected and in the other, the inert partial transmission is neutral vorge-: is selected, both clutches of the partial transmission are fully open, the drive unit runs at an idle speed, the vehicle by a Vehicle brake is held at a standstill, with the following steps are carried out sequentially: a) the clutch of the inactive subtransmission is moved to an initial position along the

Travel of the clutch driven, in which the clutch is at least partially open b) the clutch of the active sub-transmission is several times from the fully open position to a predetermined moment that is driven by a predetermined value greater than the predetermined Tastpunktmoment towards closing, in each case the position of the clutch of the active partial transmission at which the torque of the drive unit is equal to the predetermined Tastpunktmoment, is evaluated as Tastpunktposition c) the average over the determined Tastpunktpositionen due to the repeated

Driving the clutch of the active sub-transmission in the direction of closing in step b) were determined is formed d) the clutch of the inactive subtransmission is driven by a predetermined distance in the direction of closing and the process is continued in step b) until the clutch of the inactive subtransmission has reached an end position in which the clutch is at least partially closed. In a preferred embodiment of the invention, it is provided that in step a) the initial position of the clutch of the inactive partial transmission is the fully open position.

In a further preferred embodiment of the invention, it is provided that, in step b), the clutch of the active subtransmission is repeatedly moved in each case in the ramp direction in the direction of closing.

In a further preferred embodiment of the invention, it is provided that in step b) the clutch of the active subtransmission is driven three times in the direction of closing.

In a further preferred embodiment of the invention, it is provided that in step b) the predetermined value by which the predetermined moment is greater than the predetermined Tastpunktmoment is 0.1 to 75 percent of the predetermined Tastpunktmoments.

In a further preferred embodiment of the invention, it is provided that in step b) the predetermined torque is a predetermined engine torque of the drive unit

In a further preferred embodiment of the invention, it is provided that the predetermined distance of the clutch of the inactive subtransmission in step d) has the same value in each passage of step d).

In a further preferred embodiment of the invention, it is provided that in step d) the end position of the clutch of the inactive partial transmission is the fully closed position.

In a further preferred embodiment of the invention, it is provided that, in step b), starting from the fully open position to a predetermined moment which is greater than the predetermined Tastpunktmoment in the direction of closing, a filtering of a clutch position signal and the Torque signal, in particular the engine torque signal is performed with a filter with the same properties.

In a further preferred embodiment of the invention, it is provided that, when the inactive clutch is fully opened, a touch point position of the active clutch is determined in step b) which deviates too far from the touch point position previously determined by another method for determining the touch point position, in particular a touch point startup , is waived on the determined in step b) Tastpunktposition in the averaging of step c) to take into account or to take into account by a weighting weaker.

With the method according to the invention thus the determination of the crosstalk behavior is carried out for the hitherto designated active coupling. The crosstalk behavior is present as the average value of the determined touch point positions against the clutch position of the inactive clutch. The process now also has to be carried out for the hitherto inactive coupling.

With the method according to the invention, the repeated execution of the determination of the crosstalk behavior - ie the parameter determination for the over-talk model - can also be carried out during each workshop stay without the need for a transmission test bench being necessary.

Further advantages and advantageous embodiments of the invention are the subject of the following description and the following figures.

They show in detail:

Figure 1 is a block diagram of a known in its construction per se dual-clutch transmission with associated electronic control device

Figure 2: Position ramps on the active clutch affect the engine torque and the engine speed

FIG. 3: Exemplary ascertained curves for crosstalk Figure 4: Represent moment by position

FIG. 5: schematic representation of the method according to the invention

The solution of the above-mentioned object provides for the parameters for the crosstalk model in the vehicle to be determined by means of a routine developed for this purpose and used for the later compensation of travel requirements during operation.

FIG. 5 shows schematically the method according to the invention for solving the problem. The vehicle is prepared in step 510 for the determination of the crosstalk behavior by preselecting a gear in a first, the active sub-transmission and in the other, preselecting the inactive sub-transmission neutral. Both clutches of the partial transmission are fully opened, the drive unit runs at an idling speed, the vehicle is held by a vehicle brake at a standstill. Subsequently, in method step 510, the clutch of the inactive partial transmission is moved to an initial position along the travel path of the clutch, in which the clutch is at least partially opened.

In method step 520, the clutch of the active subgear is driven several times from the fully open position to a predetermined moment by a predetermined value is greater than the predetermined Tastpunktmoment in the direction closing, wherein in each case the position of the clutch of the active subtransmission to the torque the drive unit is equal to the predetermined Tastpunktmoment is evaluated as a Tastpunktposition.

In method step 530, the mean value over the determined Tastpunktpositionen which was determined due to the repeated driving of the clutch of the active partial transmission in the direction of closing in step 520, is formed.

In method step 540, the clutch of the inactive partial transmission is moved by a predetermined distance in the direction of closing.

In method step 550, we check whether the clutch of the inactive subtransmission has reached an end position. If so, the method is terminated in step 560. If this is not the case, step 520 continues. In the following, the method will be described in more detail.

The vehicle is prepared for the determination of the crosstalk behavior by selecting a gear in the active partial transmission and in the neutral partial transmission neutral. The drive motor, usually an internal combustion engine, is ready and running at idle speed. Both clutches are fully open. The brakes of the vehicle are actuated. This takes place in method step 510.

On the inactive clutch, a fixed position is approached - which takes place in method step 510 - which is increased in each cycle - which corresponds to the course of step 520 to step 550 - to the next value, which in step 540 'follows. In this case, a plurality of positions in the entire travel path of the clutch actuator belonging to the inactive clutch are predetermined. Advantageously, a uniform distribution of the total path into equidistant sections between the fully open and the fully closed position proves - which is checked in step 550 - including these two positions themselves.

The active clutch is now closed several times - in step 520 - per cycle ramped up to a small moment above the Tastpunktmoment. FIG. 2 shows by way of example a cycle in which the inactive clutch 120 is fixed at 35 mm, while on the active clutch three position ramps 110 are driven to just above the touch point.

If the engine torque signal delivered by the vehicle exceeds the defined one

Tastpunktmoment so the current clutch position is interpreted as a position for the touch point, which is provided in step 520. For each individual ramp in the cycle, a touch point position can be determined. At the end of the cycle, the average is then averaged over all determined touch point positions, which takes place in method step 530. For one cycle, this results in exactly one averaged touch point position. Measurements show that the averaged sense point position shifts to smaller values the farther the inactive clutch is closed.

Plotting the deviations between the averaged Tastpunktpositionen at not fully open inactive clutch and the average Tastpunktposition with fully open inactive clutch on the associated position of the inactive clutch, we obtain a curve that gives the crosstalk again. The absolute touch point Positions are thus adjusted by the touch point position with the inactive clutch open. FIG. 3 shows, by way of example, the determined characteristic curves for the crosstalk of both clutches 210, 220 of the dual-clutch system.

The method described above is thus carried out separately for both the one and the other clutch of the dual clutch system.

Close the active clutch:

There are several possibilities for closing the active clutch up to a torque that is above the contact point torque: e) The active clutch is moved up to just above the current position in the

Software stored touch point position closed. Since the Tastpunktposätion will be different in each cycle, there is a risk that the drive motor, especially in an internal combustion engine, stalled. f) The active clutch is closed by a position ramp until the engine is on

Moment greater than the required Tastpunktmoment indicates. Since the engine torque signal in the vehicle can be subject to strong noise / interference influences (eg due to the connection of electrical consumers), it may happen that the required torque threshold is reached much sooner in the signal displayed by the engine, thus falsely determining a too small touch point position for this ramp , g) The active clutch is closed by a position ramp until the engine speed drops significantly below the idle speed! sinks. In Figure 2, the course of the engine speed is exemplified.

It is conceivable to combine the conditions e), f) and g) via a suitable logic.

Filtering the signals:

When determining the touch point during a ramp of a cycle, when filtering the position signal and the motor torque signal with a filter having the same properties, the signal curve for the evaluation of the achievement of the required torque threshold, the - as described above - a small moment is above the Tastpunktmoment, be smoothed.

In this case, not only the measured engine torque but also the clutch position is filtered and then to use these two signals for the evaluation. Both signals, the measured engine torque, as well as the measured clutch position, are compared with a filter with the same characteristics, i. same parameters, filtered.

By filtering the signals with a filter having the same characteristics, the signal of the coupling position is equally delayed as the torque signal. This eliminates the hitherto prevailing delay of the filtered torque signal compared to the unfiltered, measured clutch position signal.

So if the position signal and the torque signal with a filter with the same

Filtered properties, resulting in the same phase shift on both signals, so that in the representation of the characteristic 330, moment after position, the phase shift has no influence, as can be seen from Figure 4.

Any torque threshold:

Alternatively, the clutch can be closed to any other torque threshold instead of just above the touch-point torque, but it should be noted that the smaller the torque threshold, the stronger the effect of noise / disturbances of the engine torque. The larger the torque threshold is assumed, the easier it would be to stall the engine using an internal combustion engine as the prime mover.

Plausibility check of the determined touch point positions:

The averaging of the determined touch point positions or positions belonging to the selected torque threshold can be extended by a plausibility check:

- When the inactive clutch is open, a touch point of the active clutch is expected near the previously determined by the Tastpunktinbetriebnahme tactile point. If the touch point, which is determined by the ramp, deviates too much, it is possible, for example, to dispense with this special measuring method. to be taken into account in averaging, or to be taken less into account by a suitably chosen weighting.

Since the inactive clutch is only ever closed a little further in each cycle than in the last cycle, it can be expected that newly determined touch point / torque threshold positions within a band will be around the last determined tactile / torque threshold position of the last cycle.

It is known from measurements that the touch point / momentary position changes monotonically for a largely closed inactive coupling. It can thus be checked for monotony in this area.

Plausibility check of engine torque:

When the active clutch is fully open, the engine torque signal provided by the engine should be constant. Stronger changes suggest that the sig. is subject to interference. The beginning of the ramp could be delayed in this case until the engine torque signal has stabilized again or cancel the process if necessary.

Waiver of the touch point commissioning:

Alternatively, in the service on the Tastpunktinbetriebnahme be dispensed with for reasons of timing and the Tastpunktposition derived from the determination of the Tastpunkt- / torque threshold position for a fully open inactive coupling from the presented here determination of the parameters for the crosstalk model.

Use of engine speed information:

Alternatively, instead of an engine torque threshold, in which an associated clutch position is determined, the falling below an engine speed threshold can be used. However, the prerequisite is that the motor control does not adapt too much and a similar behavior is reproducible.

Repeated parameter determination during service or inspection: The repeated execution of the parameter determination for the crosstalk model can thus also be carried out during each visit to the workshop.

In order to avoid damaging influences on the torque accuracy during the change of power transmission from one part clutch to the other, and to be able to provide a moment at the touch point adaptation via the evaluation of the transmission input speeds, which allows the touch point adaptation, it is necessary to have precise parameters for the crosstalk behavior of the Detecting coupling.

It has already been proposed to determine the parameters for a crosstalk model on the commissioning test bench, for the replacement of couplings in the service case in the workshop there is currently no way to determine the parameters for a crosstalk model. The method presented here makes it possible to determine the parameters for a crosstalk model directly in the vehicle by executing a diagnostic command. This thus opens up the possibility of the parameters of the crosstalk model during each inspection NEN re-ler _^ and to adjust the clutch wear.

According to Figure 1, a per se known Doppelkupplungs- or parallel gearbox, for 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 pairings of wheels, for example for producing a rotationally fixed connection between the arranged on the input shaft 8 or 10 wheel with the respective input shaft 8 or 10, which meshes with a respective, permanently connected to the output shaft 12 rotatably connected to the wheel, actuators 18 and 20 are provided For example, each may include a switch actuator and a select actuator. 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.

For controlling the actuators 14, 16, 18 and 20 is an electronic control device 26 with microprocessor and associated program and data storage, the outputs each one of the actuators control and their inputs 28 with sensors 30, 32 and 34 respectively. are connected, which detect the rotational speed of the drive shaft 6, the input shaft 8 and the input shaft 10, 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 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 may 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).

The torque which can be transmitted by the clutch is important for the function of a clutch and is stored in a memory of the control device 26 as a curve indicating the transmittable clutch torque depending on the position of a clutch actuator, for example a clutch lever. In a change of the functional state of the clutch due to wear and the like, the characteristic curve must be updated, which is done by adaptation method, including, for example, the touch point of the clutch checked while driving and must be adapted to any resulting changes in the coupling properties.

FIG. 1 shows a block diagram of a dual-clutch transmission known per se with its construction and associated electronic control device. In the dual clutch transmission shown in Figure 1, in the respective partial transmission 22 or 24, the clutch is open, in each case a gear are engaged, while the effective gear ratio of the transmission is determined by that part gear 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. If the clutch K2 takes over the torque transmission, if not at least one of the clutches K1, K2 slips simultaneously, destroys the transmission by overdetermination of the translations. Therefore, at least temporarily, when both clutches K1, K2 are closed at the same time beyond its touch point, being defined as the touch point that point from which the clutch increases as Schüeßen torque transmits (in the touch point torque of at most a few Newton meters is transmitted) made a slipping state in which at least one of the two clutches K1, K2 slips.

LIST OF REFERENCE NUMBERS

drive shaft

input shaft

10 input shaft

12 output shaft

14 actor

16 actor

18 actor

20 actor

22 partial transmissions

24 partial transmissions

26 control device

28 inputs

30 sensor

32 sensor

34 sensor

K1 clutch

K2 clutch

110 active clutch

120 inactive clutch

210 clutch 1

220 clutch 2

310 measured moment over measured position

320 filtered moment over measured position

330 filtered moment over filtered position

510 process step

520 process step

530 process step

540 process step

550 process step

560 process step

Claims

claims

1. A method for determining the crosstalk behavior of a dual clutch system in a dual clutch transmission in the drive train of a motor vehicle having a drive unit, wherein the dual clutch transmission comprises two partial transmissions, each partial transmission is assigned a respective friction clutch of the dual clutch system, which is arranged between each of a partial transmission and the drive unit, characterized characterized in that in a first, the active sub-transmission one gear is preselected and in the other, the inert partial transmission neutral is selected, both clutches of the partial transmission are fully open, the drive unit runs at an idle speed, the vehicle is held by a vehicle brake at a standstill, wherein subsequent steps are performed sequentially:

a) the clutch of the inactive sub-transmission is moved to an initial position along the travel of the clutch in which the clutch is at least partially open b) the clutch of the active sub-transmission is several times from the fully open position to a predetermined moment by a predetermined Value is larger than the predetermined Tastpunktmoment driven in the direction of closing, in each case the position of the clutch of the active sub-transmission at which the torque of the drive unit is equal to the predetermined Tastpunktmoment, is evaluated as Tastpunktposition c) the average over the determined Tastpunktpositionen due to the repeated driving d) the clutch of the inactive subtransmission is driven by a predetermined distance in the direction of closing and the process is continued in step b) until the clutch of the i naktive sub-transmission has reached an end position in which the clutch is at least partially closed

2. The method according to claim 1, characterized in that in step a) the initial position of the clutch of the inactive partial transmission is the fully open position.

3. The method according to claim 1 or 2, characterized in that in step b) dre coupling of the active sub-transmission is repeatedly driven in each case rampwise in the direction of closing.

4. The method according to any one of the preceding claims 1 to 3, characterized in that in step b) the coupling of the active sub-transmission is moved three times in the closing direction.

5. The method according to any one of the preceding claims 1 to 4, characterized in that in step b) the predetermined value by which the predetermined torque is greater than the predetermined Tastpunktmoment 0, 1 to 75 percent of the predetermined Tastpunktmoments.

6. The method according to any one of the preceding claims 1 to 5, characterized in that in step b) the predetermined torque is a predetermined engine torque of the drive unit.

7. The method according to any one of the preceding claims 1 to 6, characterized in that the predetermined distance of the clutch of the inactive subtransmission in step d) has the same value in each pass of step d).

8. The method according to any one of the preceding claims 1 to 7, characterized in that in step d) the end position of the clutch of the inactive Teügetriebes is the fully closed position.

9. The method according to any one of the preceding claims 1 to 8, characterized in that when in step b), starting from the fully open position to a predetermined moment which is larger by a predetermined value than the predetermined Tastpunktmoment is moved in the direction of closing, a Filtering a clutch position signal and the torque signal, in particular the engine torque signal is performed with a filter with the same properties.

10. The method according to any one of the preceding claims 1 to 9, characterized in that when a fully opened inactive clutch a Tastpunktposition the active clutch in step b) is determined, which is too far from the, previously by another method for determining the Tastpunktposition particular deviates a touch point position determined by a Tastpunktinbetriebnahme, it is waived in Step b) to take into account the detected scanning point position in the averaging of step c) or to take it into account more negatively by means of a weighting.