DE102006042357A1 - Method for detecting the application point of a clutch, in particular a wet starting clutch - Google Patents

Abstract

The method for detecting the application point of a clutch, in particular a wet startup engine torque Mmotref and the current engine speed gradient omegamotpref as reference points; - Calculating a reference clutch torque Mkref at the beginning of the implementation of the method according to the following formula: Mkref = Mmotref - Jmot * omegamotpref, where Jmot is the equivalent mass inertia of the engine; - Calculating the clutch torque Mk with the current values for the engine torque Mmot and for the engine speed gradient omegamotp cyclically according to the following formula: Mk = Mmot - Jmot * omegamotp and - Detecting the application point, if there is a significant increase of the calculated clutch torque Mk with respect to the clutch reference torque Mkref is coming.

Description

The The present invention relates to a method of detection the application point of a clutch, in particular a wet starting clutch, according to the generic term of claim 1

at a vehicle comprising a gearbox in order to be able to start or to create traction in the drive train, a clutch in Be engaged, i. moment must be transmitted at the clutch can be.

at a hydraulically actuated According to the state of the art, the clutch is applied to the clutch via a clutch produced with pressurizable piston, to the required Being able to build up pressure, the possibly empty piston chamber is filled and a certain "blind pressure" - caused by springs, Friction ... - be built up must transmit torque before the clutch starts.

in this connection is the "blind pressure" from vehicle to vehicle differently; furthermore, it is dependent on the respective ambient conditions, For example, on the temperature, speed, etc. dependent.

Regarding of ride comfort it is crucial to the point at which a clutch is just beginning to transmit moment, in the following application point called to accurately detect, to control the closing process optimal or to be able to regulate.

at Transmissions which have a hydraulic torque converter, According to the prior art, the application point of the clutch on the basis of Influence of the pressure on the converter output speed detected, wherein upon reaching the application point, the converter output speed bends. However, this procedure is in transmissions, which have a starting clutch and no converter, not possible.

From the EP 0 550 222 81 a method is known for determining the point of contact of a friction clutch, in which the engine is operated at idle speed, the idle position of the transmission is selected, an output shaft of the friction clutch is acted upon by a predetermined braking torque and the rotational speed of the output shaft of the friction clutch is detected. Here, a comparison signal for a speed is first generated, which is lower than the idle speed; then a differential speed between the speed comparison signal and the detected speed of the output shaft is formed and the friction clutch is engaged to such a degree that the differential speed is minimized, then the Kupplungsberührpunktsignal is set according to the degree of Kupplungseinrückens when the detected speed of the output shaft of the friction clutch is within a predetermined range of the speed comparison signal.

A method for determining the contact point of a friction clutch is known from EP 0 635 391 B1 known. Here, the engine is operated at idling speed, the idle position of the transmission is selected, an output shaft of the friction clutch is applied with a predetermined braking torque and a reference speed is selected which is lower than the idling speed. In addition, the rotational speed of the output shaft of the friction clutch is detected to determine the transmission input rotational speed and the friction clutch is engaged with a first engagement amount, wherein a first degree of clutch engagement is detected when the transmission input rotational speed reaches the reference rotational speed. Then, by varying the engagement amount, the clutch is released by a first offset amount from the first clutch engagement amount and engaged with a second engagement amount smaller than the first dimension, and the clutch touch point is detected when the transmission input rotational speed reaches the reference rotational speed when engaged with the second amount ,

Moreover, from the EP 1 437 520 A1 discloses a method for controlling an automatically actuated clutch in which the torque to be transmitted is controlled according to a clutch characteristic in dependence on the clutch position, wherein the clutch characteristic is corrected to compensate for changes in the clutch behavior. Here, a minimum and a maximum characteristic are generated to adapt the clutch characteristic; a valid, interpolated clutch characteristic, which is adapted to influencing variables on the clutch behavior, is calculated by interpolation between the values of the minimum characteristic and the values of the maximum characteristic. In the known method, the contact point of the coupling is also calculated by interpolation of the contact points of the minimum and maximum characteristic curves.

The DE 196 52 244 A1 describes a method for controlling or regulating a torque transmission system arranged in a vehicle, within the scope of which the gripping point of the system can be adapted in at least one operating point by virtue of an accumulatable value of the gripping point usable by a control unit being at least approachable, adaptable or adaptable to an actual value, wherein the value of the physical grip point due to measurements or calculation directly or indirectly deducible. Preferably, an engagement position is identified as a grip point by the control unit, this value being stored as the value of the grip point.

in this connection the value stored as gripping point can be made up of at least one Value of a transferable Clutch torque at least one predetermined engagement position of the torque transmission system be determined; the value of a transferable Clutch torque and / or a difference of such values may be at least one value of the engine torque and / or a difference be determined by motor torque values.

The DE 103 08 699 A1 describes a method for driving a creep torque on a clutch in an automated transmission. In the known method, the time of construction and / or the course of the creep torque is determined as a function of at least one operating parameter of the vehicle,

The DE 102 33 772 A1 describes a method for compensating for deviations in the transmission path of a clutch of a vehicle, in which the gripping point is corrected on the clutch and a dynamic balance is evaluated on the engine during a slip phase to correct the coefficient of friction on the clutch. In the known method, the balance is evaluated at arbitrary times and the respective deviations are separated at the engine torque and at the clutch torque for each operating condition.

Of the The present invention is based on the object, a method for detecting the application point of a coupling, in particular specify a wet starting clutch, soft in as possible a short time one possible delivers exact result.

These The object is solved by the features of claim 1. Further Embodiments of the invention and advantages are apparent from the dependent claims.

Therefore is proposed for detecting the application point of a clutch to observe the dynamic engine torque.

According to the invention will be the current engine torque Mmotref and the current engine speed gradient omegamotpref stored as reference points.

With these reference points and the equivalent inertia of the motor Jmot a reference clutch torque Mkref is calculated at the beginning of the search of the application point according to the following formula: Mkref = Mmotref - Jmot · omegamotpref ,

In the following, this equation is used to cyclically calculate the current Mk for the clutch torque from Mmot for the engine torque and omegamotp for the engine speed gradient: Mk = Mmot - Jmot · omegamotp ,

According to the invention Mooring point detected when there is a significant increase in the calculated Clutch torque Mk with respect the coupling reference torque Mkref comes.

If the point of application is recognized by means of the method according to the invention, can be checked cyclically whether the clutch is still engaged, taking care for this purpose the set pressure at the coupling is observed. If this pressure for a defined Time smaller than the previously detected and thus known application pressure is, it is recognized that the clutch is no longer engaged, so that, if necessary, a new filling is required.

Of another is provided according to the invention, that, e.g. due to an intervention in the emergency program, canceled is checked cyclically as a deposit criterion, whether the target pressure for a defined Time is less than the previously detected and thus known application pressure. If this is the case, it is recognized that the clutch is no longer in Intervention is.

The Invention will be described below with reference to the accompanying figure, which is a inventive method Illustrates illustrative flowchart, explained in more detail by way of example.

To The beginning of the procedure is being examined whether the clutch fills must be (decision "state Filling "). Is this the case, then it is decided whether the Befüllphase be initiated should or should not (decision "Start Filling "). Will the filling phase initiated, then the application criteria for the procedure used initializes or, if initialization has already taken place, the application criteria checked and subsequently evaluated.

Accordingly, the current engine torque (Mmotref) and the current engine speed gradient (omegamotpref) are stored as reference points and a reference clutch torque Mkref calculated according to the following formula: Mkref = Mmotref - Jmot · omegamotpref ,

Then be the application criteria checked (Condition "application criteria check ") and evaluated (Condition "application criteria evaluate ") to the To put on landing status.

is the filling phase not active, the decision "Created" is transferred, when, if the clutch is already created, the discard criteria cyclically tested (Check "Ablegekriterien" status) and then evaluated (Condition "Discard criteria evaluate "), to set the landing status. For the case that the clutch is not applied and no application the clutch desired is, the landing status is retained.

When Discard criterion is checked whether the target pressure for a defined time is smaller than that previously detected and thus known application pressure. If this is the case, it is recognized that the Clutch is no longer engaged. According to the invention, several suitable Deposit criteria checked in parallel become.

According to the invention can for detecting the application point also two or more methods be used, which run in parallel, the detection as successful as soon as a method detects the point of application; i.e. An OR link is provided for detecting the application point.

Claims (5)

Method for detecting the application point of a clutch, in particular a wet starting clutch, characterized in that it comprises the following steps: - storing the current engine torque Mmotref and the current engine speed gradient omegamotpref as reference points; Calculating a reference clutch torque Mkref at the beginning of the implementation of the method according to the following formula: Mkref = Mmotref - Jmot · omegamotpref, where Jmot is the equivalent mass inertia of the motor; - Compute the clutch torque Mk with the current values for the engine torque Mmot and for the engine speed gradient omegamotp cyclically according to the following formula: Mk = Mmot - Jmot · omegamotp and - detecting the application point when there is a significant increase in the calculated clutch torque Mk with respect to the clutch reference torque Mkref. Method for detecting the application point of a Coupling according to claim 1, characterized in that when the Mooring point is detected, cyclically checking whether the clutch is still is engaged, for which purpose the target pressure of the clutch is observed and where, if the clutch pressure for a defined Time smaller than the previously detected and thus known application pressure is recognized that the clutch is no longer engaged. Method for detecting the application point of a Coupling according to one of the preceding claims, characterized that, for the case that the filling phase is not initiated or canceled, with applied clutch Disclosure criteria checked cyclically and subsequently be evaluated, where for the case that the clutch is not applied and not closing the Coupling desired is, the landing status is maintained. Method for detecting the application point of a Coupling according to claim 3, characterized in that as a deposit criterion checked is, whether the target pressure for a defined time is smaller than that previously detected and thus known application pressure, which, if so, it is recognized that the clutch is no longer engaged. Method for detecting the application point of a Coupling according to claim 3 or 4, characterized in that several suitable deposit criteria are checked in parallel.