JP4500800B2 - Method for correcting the clutch characteristic curve - Google Patents

Description

  The invention relates in particular to a method for correcting the clutch characteristic curve of an automatic twin clutch transmission of an automobile.

  A twin-clutch transmission typically includes a first transmission input shaft with a first clutch and one or more odd gear gears attached, a second clutch and one or more even gear gears. And a second transmission input shaft to which a gear is attached. In the twin clutch transmission thus formed, the shifting process, i.e. the shift from a valid active gear to the next upper or lower gear, the so-called target gear, is first made to this target gear. However, this can be done, for example, via a shift sleeve and a synchronizer coupled to the shift sleeve, but with subsequent simultaneous disengagement of the clutch corresponding to the transmission input shaft of the gear in operation and The clutch corresponding to the transmission input shaft of the target gear is closed. That is, power transmission is alternately performed via the first or second transmission input shaft.

  When such shift stroke control is automated, the traction force interruption and shift shock are avoided via the corresponding clutch adjustment force control, i.e. the transition from the operating gear to the target gear is as comfortable as possible. To achieve this, a relatively accurate grasp of the friction values of both clutches is necessary.

  Since the friction value of the clutch changes based on wear, temperature changes, dirt and other influences, the clutch to the instantaneous friction characteristic, as is known, for example, from US Pat. Control fit is desirable. By correcting the characteristic curve, the frictional characteristic in which the relationship between the torque transmitted by each clutch and the clutch adjustment force corresponding to this torque or the control value associated with this clutch adjustment force is changed is performed. If the torque is large, the confirmation of the respective transmitted torque and thus the friction value of the clutch is possible via the corresponding driving engine operating parameters and characteristic maps. However, if the torque is less than 20 Nm, this is not possible or is associated with a large inaccuracy. However, this very small transmission torque region is important for a comfortable start and control of the shifting process.

Patent Document 2 describes a method for correcting a clutch characteristic curve of an automatic twin clutch transmission that is particularly suitable for a small transmission torque. In this method, first, a free transmission input shaft is supported. A constant clutch adjusting force is generated to close the clutch to be operated, and thus the synchronizer corresponding to one gear of the free transmission input shaft is operated, and the operation of the synchronizer is released at a later time, Next, the gradient of the rotational speed of the free transmission input shaft is confirmed, the transmission torque of the clutch corresponding to the free transmission input shaft is confirmed, and finally, the clutch characteristic curve of the clutch corresponding to the free transmission input shaft is Clutch adjustment force and corresponding transmission torque It is corrected using the value. This method is based on the assumption that synchronisation, i.e., on a free transmission shaft, the transmitted clutch torque is smaller than the torque transmitted by the synchronizer. In other cases, the method works incorrectly.
German Patent Application Publication No. 197 51 455 specification German Patent Application Publication No. 199 31 160

  Therefore, the problem underlying the present invention is to develop and develop a known method so that a selective method for correcting the clutch characteristic curve of an automatic twin clutch transmission, in particular to reduce the control costs, is realized. It is to let you.

  This problem presented previously is solved by a method according to the features of claim 1. Further advantages and details of the invention can be seen from the subclaims.

  There are many possibilities to form and develop the method according to the invention. For this reason, reference should first be made to the claims that follow claim 1.

  Hereinafter, a method for correcting the clutch characteristic curve of an automatic twin clutch transmission will be described in detail with reference to the drawings based on the change of the method.

  FIG. 3 schematically shows a known twin clutch transmission G to which the method according to the invention can be applied. The twin clutch transmission G includes a pair of gears corresponding to six forward gears G1 to G6 and a reverse gear R. On the output side, the respective gears are rotatable and are supported by the transmission output shaft W3 via the shift and synchronizers S1 to S4 or can be coupled to the output shaft. The shift and synchronizers S1, S3 and S4 are effectively formed on both sides, whereas the synchronizer S2 is effectively formed on only one side. On the input side, each gear is fixedly coupled to one of the two transmission input shafts W1 and W2. The odd gears G1, G3 and G5 and the reverse gear R are attached to the first transmission input shaft W1, and the even gears G2, G4 and G6 are attached to the second transmission input shaft W2. The two transmission input shafts W1 and W2 are coupled to independent clutches K1 or K2, respectively, through which the transmission input shafts can be coupled to or separated from the drive engine M. It is. During standard driving, one of the gears G1 to G6 is connected and the clutch K1 or K2 connected to the corresponding transmission input shaft W1 or W2 to which the gear is attached is closed.

  In the shift process, first, a target gear corresponding to another released clutch K1 or K2 is connected. The transition from the active gear to the target gear is then performed by simultaneously releasing the active gear clutch and closing the target gear clutch. That is, the transmission power flow is the first clutch K1, the first transmission input shaft W1 and the gear pair attached thereto, or the second clutch K2, the second transmission input shaft W2 and the gear pair attached thereto. It alternately passes through one of the gear pairs to the transmission output shaft W3. For the method according to the invention, the correspondingly released clutch K1 or K2, which is not currently used, the corresponding released transmission input shaft W1 or W2, and the corresponding gears G1 to G6 of the transmission input shaft W1 or W2, respectively. Devices S1 to S4 are used.

  A variant of the method according to the invention for correcting the clutch characteristic curve of the automatic twin clutch transmission G illustrated in FIG. 1 is configured for application to a motor vehicle. The method for correcting the clutch characteristic curve is performed in the released clutch K1 or K2 of one of the two transmission input shafts W1 or W2 that is not currently coupled for power transmission. Before carrying out the method, it is first checked whether the vehicle is in a quasi-stationary driving state, i.e. not in the acceleration or deceleration phase. If this check results in a negative result, it is possible to branch to the program end without executing the steps of the program, and from there, for example, to branch back to the upper control program. In the quasi-static operation state, first, a constant clutch adjustment value is generated in the clutch (K1; K2) corresponding to the free transmission input shaft (W1; W2). The clutch adjustment value can be, for example, a hydraulic pressure for adjusting the clutch adjustment force FK or an electrical value. This depends on the hydraulic and / or electrically actuable actuators used respectively. The clutch torque MK according to the constant value of the clutch adjustment value is advantageously in the range from 5 Nm to 20 Nm. The correspondence between the constant value of the clutch adjustment value and the clutch torque MK is read from the characteristic curve used so far, and this characteristic curve is corrected. The released clutch torque MK of the clutch K1 or K2 has the result that the corresponding free transmission input shaft W1 or W2 is accelerated to the engine speed nMot of the drive engine M.

  Thereafter, the process waits until the rotational speed nfW of the free transmission input shaft W1; W2 becomes equal to the engine rotational speed nMot. In the case of a dry clutch, the clutch torque MK can be selected such that the clutch is at least lightly closed so that the free transmission input shaft W1 or W2 is at the engine speed nMot of the drive engine M. In the case of a wet clutch, the drag torque is such that the free transmission input shaft W1 or W2 is linked to the engine speed nMot of the drive engine M even when the clutch is released. Nevertheless, if there is slip, the system waits until the rotational speed nfW of the free transmission input shaft W1; W2 becomes sufficiently constant.

  Gears G1 to G6 of the synchronizers S1 to S4 to be operated are set. The corresponding gears can always be identical for each of the two transmission input shafts. However, depending on the currently engaged working gear, the next upper or lower gear or a synchronizer corresponding to this gear may be set. The operation of the synchronizers S1 to S4 corresponding to the gears G1 to G6 of the free transmission input shaft W1; W2 is performed with a synchronizing force that increases as the value of the synchronization adjustment value increases. In other words, it is as if it is not synchronized. Shifting of the gear, i.e., this gear engagement, is avoided. As the closure of the synchronizer increases, an increased sync torque MSync is also transmitted. As soon as the synchro torque MSync exceeds the clutch torque, the rotational speed nfW of the free transmission input shaft W1; W2 deviates from the engine rotational speed nMot. The value of the synchronization adjustment value at which this divergence is performed is confirmed.

  The synchronization adjustment value can be, for example, a hydraulic pressure or an electrical value for adjusting the synchronization force FSync. A known stored characteristic curve is applied for the correspondence between the synchronization adjustment value or the synchronization force FSync and the synchronization torque MSync generated thereby. Both the synchronization mechanism, i.e. this characteristic curve, changes very slightly with time and is therefore suitable for correcting the clutch characteristic curve.

  In the next method step, the value of the confirmed synchronization adjustment value is made to correspond to a constant value of the clutch adjustment value. Therefore, the points of the characteristic curve are realized and thus the characteristic curve is corrected.

  In particular, the clutch torque corresponding to the synchronized torque corresponding to the value of the confirmed synchronization adjustment value is made to correspond to the constant value of the clutch adjustment value. It can be seen that in handling, the friction or drag torque resulting from the free transmission input shaft and the corresponding co-rotating structure can be taken into account.

  The characteristic curve points to be corrected may be fixed or may be changed within a predetermined range. This range is advantageously limited by the clutch torque MKo of the released clutch and by the maximum clutch torque MKmax that should not be exceeded to protect the synchro ring.

The method according to the invention is particularly advantageously suitable for checking the drag torque of the wet clutch and for taking this into account when setting the clutch engagement point. In this case, the drag torque is mostly dependent on the current operating parameters, depending on the viscosity of the hydraulic oil, which in turn depends on the oil temperature. Here, the method according to the present invention first confirms the drag torque MKo of the released clutch in the first step, and then confirms the drag torque when the clutch is slightly closed in the second step. Can be used to make corrections that take into account. In this case, in the second step, the clutch torque MK is adjusted based on the stored characteristic curve so far, and this clutch torque is released in the first step by a preset torque difference ΔM. It is larger than the drag torque MKo of the clutch. The preset torque difference ΔM is 1 to 3 Nm, particularly in the case of a very small Nm, for example, a clutch capacity of 400 Nm. With this adjusted clutch torque, the method according to the invention is repeated and the adjusted characteristic curve points are corrected with MK. In this way, the clutch engagement point of the wet clutch can be monitored depending on the operating conditions. The first and second method steps are particularly short in time and follow each other.

  With the clutch torque MKo, in particular the drag torque of the wet clutch can be confirmed and taken into account. In this case, the method according to the invention first confirms at the clutch torque MKo the drag torque of the wet clutch, i.e. when the clutch is fully disengaged, and subsequently at one or more points of the characteristic curve. It can be used to make corrections that take into account the confirmed drag torque.

  Advantageously, the method according to the invention is repeated at regular or irregular time intervals, mostly depending on the preset driving performance of the vehicle.

  After confirming the synchronization torque outside the expected synchronization torque region, the clutch engagement point is particularly corrected. For this reason, the method according to the invention is repeated at other points of the clutch characteristic curve.

  In order to clarify the previously described method, FIG. 2 shows in a simplified linearized manner the temporal transition of the rotational speed n and the torque M over time t. The uninterrupted horizontal line 10 shows the transition of the engine speed nMot. A broken line 20 shows a transition of the rotational speed nfW of the free transmission input shaft of the automatic twin clutch transmission G. The dash-dot line 14 reproduces the transition of the synchro torque MSsync generated by the used synchronizers S1 to S4, and the uninterrupted line 16 reproduces the transition of the torque MK transmitted by the released clutch K1 or K2. .

  Here, since the quasi-stationary operation of the vehicle is assumed, the engine speed nMot remains constant over time t. First, the rotational speed nfW of the free transmission input shaft is similarly constant, and in this example, is the rotational speed between the stop state and the engine rotational speed nMot. At the time t1, the released clutch K1 or K2 of the automatic twin clutch transmission G is closed under the action of the clutch adjustment force FK according to a constant value of the clutch adjustment value, and therefore the released clutch K1 or K2 Torque MK is transmitted to the free transmission input shaft W1 or W2, which accelerates the free transmission input shaft W1 or W2 from the output speed to the engine speed nMot achieved at time t2. At time t3, the gear synchronizers S1 to S4, which are higher than the active gear being engaged, are operated, which generates an effective synchro torque MSsync on the free transmission input shaft W1 or W2. The synchro torque MSync is increased in a ramp shape between t3 and t5. At t4, the synchro torque MSync exceeds the clutch torque MK, and the rotational speed nfW of the free transmission input shaft W1; W2 deviates from the engine rotational speed nMot. The value of the synchronization adjustment value at which this divergence is performed is confirmed.

Therefore, the released clutch K1 or K2 starts the slip operation, the corresponding free transmission input shaft W1 or W2 is braked, and the operation of the synchronizer is released again, so that the gear shift is avoided. The brake is applied until the time t5. Furthermore, the free transmission input shaft W1 or W2 is accelerated to the engine speed nMot which is achieved again at time t6, essentially under the action of the clutch torque MK. At time t7, the released clutch K1 or K2 is separated again, and the corresponding free transmission input shaft W1 or W2 is decelerated again under the action of most of the friction torque.

  The method according to the invention is implemented in particular by corresponding control equipment not shown in detail here. A corresponding control device, in particular a corresponding transmission control device, here comprises a corresponding electrical and / or electronic structural unit and is connected via a corresponding signal line to the actuator of the synchronizer and the actuator of the engine or clutch. ing. Therefore, the transmission control device controls the shift progress and the corresponding gear de-synchronization stage in the twin clutch transmission, with the current speed of the engine shaft or transmission input shaft being set accordingly. Is transmitted to the control device via a rotation speed sensor (not shown) and further via a signal line. In particular, the transmission control device comprises a microprocessor for processing the data and storing a corresponding specially corrected characteristic curve.

  As a result, the method according to the invention makes it possible to correct the clutch characteristic curve quickly and comfortably and with components already present in the control system, so that the method is very inexpensive.

The course of the method according to the invention is shown in the form of a flowchart. Fig. 4 shows in graph form the time course of the rotational speed and torque of a free transmission input shaft according to the method according to the invention. The structure of the twin clutch transmission by a prior art is shown as a principle diagram.

Explanation of symbols

dn / dt Speed gradient FK Clutch adjustment force FSync Synchro adjustment force G Twin clutch transmission G1 First forward gear G2 Second forward gear G3 Third forward gear G4 Fourth forward gear G5 Fifth forward gear G6 6 forward gear K1 first clutch K2 second clutch M drive engine M torque MK (transmitted) clutch torque MSsync synchro torque n speed nfW free transmission input shaft speed nMot drive engine speed R reverse Gear S1 1st synchronizer S2 2nd synchronizer S3 3rd synchronizer S4 4th synchronizer t Time, time t1 Release clutch closure start t2 Free transmission input shaft to engine speed for the first time Reach t3 Synchronize Operation start t4 Deviation of free transmission input shaft speed from engine speed t5 Synchronizer operation end t6 Second arrival of free transmission input shaft engine speed t7 Release of clutch closed W1 First transmission input shaft W2 Second transmission input shaft W3 Transmission output shaft

Claims (16)

(A) a method step of generating a clutch adjustment value at a constant value in a clutch (K1; K2) corresponding to a free transmission input shaft (W1; W2);
(B) a method step of waiting until the speed (nfW) of the free transmission input shaft (W1; W2) is equal to the engine speed (nMot);
(C) Method of operating the synchronizer (S1 to S4) corresponding to the gears (G1 to G6) of the free transmission input shaft (W1; W2) in which the value of the synchronize adjustment value increases in accordance with the increase of the synchronize force Steps,
(D) a method step of confirming the value of the synchronization adjustment value at which the rotational speed (nfW) of the free transmission input shaft (W1; W2) deviates from the engine rotational speed (nMot);
(E) a method for correcting a clutch characteristic curve of an automatic twin clutch transmission of an automobile during engine operation by a method step of associating a value of a confirmed synchronization adjustment value with a constant value of a clutch adjustment value. .   2. The clutch characteristic curve according to claim 1, wherein a clutch torque corresponding to a synchronized torque corresponding to the value of the confirmed synchronization adjustment value is made to correspond to the constant value of the clutch adjustment value. the method of. For the clutch adjustment value of the first constant value according to the release of the clutch, according to claim 1 the first value of the synchronization adjustment value corresponding to the drag torque of the released clutch is characterized in that it is confirmed or A method for correcting the clutch characteristic curve according to 2.   The second value of the synchronization adjustment value according to the clutch torque of the lightly closed clutch is confirmed for the second constant value of the clutch adjustment value according to the lightly closed clutch. The method for correcting the clutch characteristic curve according to claim 1.   5. The method for correcting a clutch characteristic curve according to claim 1, wherein the synchronization adjustment value is a control value for operating the synchronization ring.   4. The method for correcting a clutch characteristic curve according to claim 3, wherein the synchronization adjustment value is a hydraulic pressure for operating the synchronization ring.   The method for correcting a clutch characteristic curve according to claim 1, wherein the clutch adjustment value is a hydraulic pressure for operating the clutch.   8. The method for correcting a clutch characteristic curve according to claim 1, wherein the correction of the clutch characteristic curve is performed when the vehicle is in a quasi-stationary driving mode. .   The method for correcting a clutch characteristic curve according to claim 1, wherein the correction of the clutch characteristic curve is repeated at regular or irregular time intervals.   10. The method for correcting a clutch characteristic curve according to claim 1, wherein the constant value of the clutch adjustment value is changed when the correction of the clutch characteristic curve is repeated.   11. The synchronizer (S1-S4) corresponding to a fixed gear (G1-G6) of a free transmission input shaft (W1, W2) is operated, respectively. A method for correcting the described clutch characteristic curve.   The synchronizers (S1 to S4) corresponding to the gears above or below the free transmission input shaft (W1; W2) are respectively operated in relation to the currently engaged gear. A method for correcting a clutch characteristic curve according to any one of claims 1 to 11.   The clutch characteristic curve according to any one of claims 1 to 12, wherein the operation of the synchronizer is performed with a constant synchronizing force (Fsync) set so as to avoid switching of the gear. Method to correct for.   The clutch characteristic curve correction according to any one of claims 1 to 13, wherein an expected clutch torque region ([Me1, Me2]) corresponding to an expected synchronized torque region is determined. How to do.   15. The method for correcting a clutch characteristic curve according to claim 14, wherein the clutch engagement point is corrected after confirming a synchronized torque outside an expected synchronized torque range. In the first steps, method steps (a) ~ (e) is implemented in the released clutch, by which, the first value of the synchronization adjustment value corresponding to the drag torque of the released clutch is confirmed, the second in step, correction is performed in the clutch closed lightly, the correction of the clutch characteristic curve of any one of claims 1 to 15 has been identified that dragged torque is characterized in that it is considered A method for correcting a clutch characteristic curve of a wet clutch by a method for

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