DE102007027702A1 - Method and device for controlling a clutch - Google Patents

Abstract

The invention relates to a method for controlling a clutch, in particular a friction clutch in a drive train of a motor vehicle, via which an internal combustion engine can be connected to a transmission, in which clutch travel points are determined with the aid of at least one learning process. To enable comfortable and safe starting operations with constant starting conditions, at least when the vehicle is inactive starting, starting from a predetermined resting point of the clutch without torque transmission, a, in the closing direction moving clutch with the aid of monitoring engine-related parameters determined, marginal Kupplungswegpunkt with low torque transmission approached. In a device for carrying out the method, a control device has means for detecting and processing engine, clutch and gearbox-relevant data and for storing clutch waypoints derived therefrom.

Description

The The invention relates to a method for controlling a clutch according to the Preamble of claim 1 and an apparatus for implementation the method according to the preamble of the claim 12th

at Vehicles with automated manual transmissions or automatic transmissions with an automatic friction clutch as controllable starting element are used to control the torque transmission between the drive motor and the transmission of an electronic control device different operational sensor data, such as engine speed, Transmission input speed, accelerator pedal position, driving speed and Switching intent supplied and after a corresponding evaluation a disengagement or engagement of the starting clutch, possibly with a variable closing or opening, triggered.

Around to ensure a flawless and comfortable driving, It is known, in automatic couplings, the individual road conditions in the adjustment of the friction partners, in particular characteristic Clutch way points, such as the Zupunkt or Anlegepunkt, via automatic Determine learning processes. This results in a coordinate system, via the specific functions of the clutch, for example, "clutch open when switching "or" waiting position when the vehicle is stationary with engaged gear until start-up signal is generated ", can be displayed are.

There the path conditions for closing as well as the opening of the clutch and thus the torque transmission the clutch over its life, in particular by Wear, as well as in the current operation by external Influences, for example, different temperatures and speed fluctuations, can change, it is necessary, the Einlernprozesse possible with each clutch operation or at least at predetermined intervals, around the relevant clutch waypoints according to the current travel conditions to adjust for the clutch operation.

Various methods for teaching characteristic clutch waypoints are known from the prior art:
The DE 103 52 611 A1 For example, proposes a method for adapting a clutch travel point defined as a grinding point with incipient engagement, in which a teaching of the waypoint is not with a clutch moving in the closing direction as in a common approach but by detecting a differential speed between the drive side and output side of the clutch when the clutch opens he follows. In addition, in order to take into account a hysteresis of the clutch travel, a second waypoint can be determined when the clutch is closing.

The DE 100 54 867 A1 describes a method for adapting a clutch travel point defined as a creep point for setting a desired creep torque. In this case, the actual transmission torque of the clutch is compared with a transmission torque of a creep point set in a preceding cycle, and assuming a deviation from a desired creep torque when the starting gear is engaged, a reference point lying between a grinding point and the creeping point, over which a new creep point is determined, which corresponds to the desired creep torque.

The DE 695 16 391 T2 describes a method for determining a clutch point defined as the contact point, wherein the clutch moves at a constant speed in the closing direction and is closed from a detected at a time interval speed difference of a transmission input shaft at two positions of the closing path to a lying before the first position touch point.

The DE 101 63 438 A1 proposes a method for determining a clutch application point, which is set as the limit point of a torque transmission which starts with further engagement of the clutch. The procedure can also be carried out with the engine off. Therein, in contrast to the conventional use of speed and motor signals, a manipulated variable is varied. In particular, the application point is detected on a discontinuity in a gradient of a disengaging force or on a value of zero accepting contact force of the clutch.

The DE 103 06 934 A1 shows another method for determining an application point with starting torque transmission without incorporating motor-related sensor data, in which an unsynchronized reverse gear is used. In this case, a contact point is determined when the vehicle and the engine is running when the torque transmission of the clutch is sufficient to move the teeth of a sliding sleeve against the teeth of a coupling body of a reverse gear in a tooth-on-tooth position.

Disadvantageously, in the known methods and the taught coordinate systems changes in the relevant Kupplungswegverhältnisse of a startup to the next start-up when in-vehicle gear standing up to now have been rather inadequate considered. However, in particular in the area of torque transfer, that is to say in the transition between open and slipping clutch, temperature and speed fluctuations may cause comfort and safety problems during starting and / or maneuvering.

Becomes For example, the starting clutch when stopping the vehicle, triggered by the clutch control, by means of a clutch actuator disengaged, for example, to prevent the internal combustion engine stalled when the speed is below an idle speed falls off and / or to a Ankriechen the vehicle at not inhibited brake, so can by a due changing clutch way points too wide open Coupling of the closing path in the subsequent starting process become relatively large until the start of torque transmission. This can cause disturbing and wear-increasing Torque surges and / or an undesirable short-term rolling of the vehicle against the selected Lead approach direction.

Becomes on the other hand, the clutch when the vehicle is stationary and inlaid Gear not disengaged, so can by a towards indenting the Clutch too far shifted Anlegepunkt already at a standstill be transferred relatively high torque, which as a result, to an undesirably strong creep of the vehicle leads.

In front In this background, the invention is based on the object Specify a method for controlling a clutch, which possible independent of operational influences largely constant provides comfortable starting conditions and ensures a high level of operational safety. Continue to an apparatus for carrying out such a method to be discribed.

The Solution to this problem arises from the features of independent method claim and the device claim, while advantageous embodiments and further developments of Invention the subclaims are removable.

Of the The invention is based on the finding that when learning or Adaptation of a coupling coordinate system starting from a first specific clutch way point, in which the clutch under All operating conditions are safely opened second clutch waypoint, in which just transmit a very low torque is, can be approached, creating each a clutch position is determined in a limited range, which is largely Consistent initial conditions for start-up and shunting operations allows.

Therefore the invention is based on a method for controlling a clutch, in particular a friction clutch in a drive train of a motor vehicle, via an internal combustion engine with a transmission is connected, at with the help of at least one learning process Kupplungswegpunkte be determined.

to Solving the problem, the invention provides that at least when the vehicle is in a starting gear, starting from a pre-determined rest point of the clutch without Torque transmission, on, in the closing direction moving coupling with the help of a monitoring motor-relevant Parameter, determined, marginal clutch waypoint with low torque transmission is approached.

to Carrying out such an inventive Method, the invention also provides a device in which a control device for controlling the clutch corresponding Means for detecting and processing engine, clutch and gearbox-relevant Data as well as for storing derived clutch waypoints having.

There in modern motor vehicles, speed and fuel injection quantity data Anyway, these data can be available an existing control device supplied to the clutch and by means of a suitably adapted transmitter or a suitable evaluation program are processed. The adjusting device The clutch is then each with the appropriate control signals applied. Thus, the inventive Method particularly cost in existing vehicles be implemented.

The the process according to the invention is particularly advantageous applicable to automated manual transmissions. in principle It may, however, be analogous to all types of powertrains and transmissions with automatic clutches, for example in dual-clutch transmissions, step machines and stepless Automatic transmissions are used.

By the method is advantageously achieved that start-up and maneuvering operations can always be initiated with the same conditions and high comfort. In particular, torque shocks and switching delays are due to excessive clutch travel in the torque transfer of the clutch or increased wear due to undesirably high friction moments at a standstill with too tight friction partners of the clutch ver avoid and the risk of unwanted rolling against the selected approach direction significantly reduced.

This is in a standing gear with the vehicle by a stable and under all conditions very little torque transmission reached. For this purpose, a rest point is first determined at the clutch is safely open under all circumstances, So no torque transfers. This resting point serves as a starting point for clutch positioning as well as reference point for the acquisition of engine-relevant data without Torque transmission to the gearbox. As a motor-relevant Parameters may include the idle speed and / or the idle fuel injection amount and optionally also the engine torque of the internal combustion engine recorded and evaluated.

The Determination of the rest point is advantageously dependent from a previously taught when the vehicle is driving point as Auxiliary coordinate. The pickup point can be taught in by, starting from fully opened clutch in the closing direction moving clutch, a speed monitoring a transmission input side secondary side of the clutch takes place and when exceeding a predetermined speed threshold at the transmission input a clutch waypoint determined as a driving point and is stored.

at The determination of the rest point is advantageous from the clutch manufacturer or design-conditioned given Mindestauskuppelweg taken into account. As a result, from the learned driving point in a simple way a rest point can be found, on the one hand, the clutch safely is open and the other hand, as close as possible is located at a touch point or Anlegepunkt.

to following positioning of the clutch on a clutch waypoint with low torque transmission is engaged Starting gear, starting from the opened clutch position at rest, the clutch in the closing direction adjusted. The beginning friction of the primary and secondary side Friction partner of the clutch causes a decrease in the speed on Internal combustion engine below the idle speed. This speed loss is by readjusting the idle injection amount over a existing idle controller of the engine control compensated, wherein in the transition area starting torque transmission the increase in the injection quantity is at least approximately proportional varies the transmission torque of the clutch.

There The idle control is relatively sensitive, can be a marginal Clutch waypoint, so close to the edge of the torque transmission lying Waypoint detected with a very low transmission torque and be set. Additionally or alternatively also the idle speed directly for the determination of beginning torque transmission of the clutch can be used.

Preferably the procedure is in each case with an engaged starting gear Vehicle - without start request - carried out. Thus, this setting reproducibly same starting conditions created for the respective approach of the driver.

in principle the resting point can not only be with already engaged gear Vehicle as starting position for setting the waypoint with low torque transfer for the on it following startup be used. Also when switching the Anfahrganges itself, the rest point can be approached advantageous.

Around no unnecessary wear, fuel consumption, and pollutant emission increasing friction work when stationary Vehicle can also be provided that with engaged starting gear with brake control via a service brake or a parking brake, if exceeded a predetermined time threshold or at the expiration of a predetermined Period of rest is approached and only at a detected Reduction of braking energy of the clutch waypoint with less Torque transmission is approached.

Farther can reduce the friction work and thus reduce the Kupplungsverschleißes be provided that when in gear without braking operation standing vehicle and already approached Clutch waypoint with low torque transmission when exceeded a predetermined period for starting the vehicle, so if the driver despite the brake released and starting lower Torque transmission within a certain period of time is not anfährt, first again the rest point by a appropriate clutch adjustment is approached. in principle It is possible that when reaching the rest point in cyclic Sequence immediately returns the waypoint with low torque transfer is approached to the possibly following startup a short operating time and a high starting comfort to back up.

To increase the ride comfort in automated manual transmissions can also be provided that opened during a switching operation while driving the clutch and then the previously learned and saved with a low-torque torque transmission when the vehicle is stationary when the vehicle is engaged.

Conveniently, can provide extra waypoints to complete of the clutch travel coordinate system. Especially can be a point where the clutch is fully engaged is, about a movement of the clutch in the closing direction until reaching an end position, ie the position at which the Path gradient of the clutch during the closing process takes the value zero, to be taught. About the previously learned pickup point may also be a preselected one besides the rest point Contact point, at which the friction partners of the coupling touch, be determined.

to Clarification of the invention, the description is a drawing an embodiment attached. It shows the single FIGURE is a flow chart for the sequence of an inventive Method for controlling an automatic friction clutch in a Drive train of a vehicle.

Therefore when the vehicle is stationary and idling the internal combustion engine first a Zupunkt and a driving point of the clutch learned. To teach in the Zupunktes is optionally already closed clutch activated in the closing direction and checked for a zero path change or, if appropriate, completely closed. To learn the driving point, the clutch is complete opened and until the detection of a speed increase at Gearbox input adjusted in closing direction. When exceeded a preset speed threshold becomes the current clutch position set as takeaway point.

From this pickup point as an auxiliary position from a rest point is approached, the at least one structurally predetermined Mindestauskuppelweg taken into account so that the clutch is independent safely opened by external influences is.

Subsequently the clutch moves in the closing direction when the starting gear is engaged. The starting gear is engaged after initiation by the driver, for example, by pressing a switch of the Neutral to a forward driving position. Here are the Idle fuel injection amount and / or idle speed observed. When determining a through the idle controller of the Internal combustion engine increased fuel injection quantity, for Compensation of the engine speed loss due to beginning friction of the friction partner of the clutch, becomes a clutch waypoint detected at very low torque transmission and the Clutch on this target point as a starting point for a expected to start.

At the Initiation of the start-up process is signaled by the start-up request the driver, ie the operation of the accelerator pedal, the Zupunkt approached, the clutch is fully engaged, what is the vehicle according to the engaged gear or the inserted gear set in motion.

additionally is advantageous a service life monitoring with inlaid Approaching stationary vehicle provided. This is when exceeded a predetermined time threshold or the expiration of a predetermined time Time, the rest point is approached and a waiting loop is switched, until this by a release signal or at the latest by the approach is interrupted. When the brake is applied For example, the enable signal may be a drop in braking energy be, so a release of the brake pedal or the parking brake. Without brake actuation, the clutch may fail after a monitoring timeout be set to a start request signal to the rest point.

Of the inventive learning cycle is preferably carried out again before each start, so that at with vehicle in gear standing independent of Parameters such as wear state, temperature or speed fluctuations a stable, very low torque transmission of the clutch is reached. Thus, start-up and maneuvering operations be initiated with always the same conditions and high comfort.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 10352611 A1 [0005]
• - DE 10054867 A1 [0006]
• - DE 69516391 T2 [0007]
• - DE 10163438 A1 [0008]
• - DE 10306934 A1 [0009]

Claims (12)

Method for controlling a clutch, in particular a friction clutch in a drive train of a motor vehicle, via which an internal combustion engine is connectable to a transmission, in which by means of at least one learning process Kupplungswegpunkte be determined, characterized in that at least when inlaid with starting vehicle, starting from a predetermined point of rest of the clutch without torque transmission, a, is determined in the closing direction moving coupling by means of monitoring engine-related parameters determined, marginal Kupplungswegpunkt with low torque transmission. Method according to claim 1, characterized in that that as engine-relevant parameters, the idle speed and / or the idle fuel injection amount and / or the engine torque of the internal combustion engine are detected and evaluated. Method according to claim 1 or 2, characterized that the rest point depends on a previously learned Carrying point is determined. Method according to claim 3, characterized that for learning the driving point, starting from open Clutch in the closing direction moving clutch, a Speed monitoring of a transmission input secondary side the clutch takes place and when exceeding a predetermined Speed threshold at the transmission input a clutch waypoint as a driving point is determined and stored. Method according to at least one of the claims 1 to 4, characterized in that in the determination of the rest point a predetermined minimum Auskuppelweg is taken into account. Method according to at least one of the claims 1 to 5, characterized in that when engaged with starting with braking operation standing vehicle when exceeding a predetermined time threshold, the rest point is approached, and at a detected drop in braking energy, the clutch waypoint is approached with low torque transmission. Method according to at least one of the claims 1 to 6, characterized in that with inlaid gear without Brake operation stationary vehicle and already approached Clutch waypoint with low torque transmission when exceeded a predetermined period for starting the vehicle first the rest point is approached again. Method according to at least one of the claims 1 to 7, characterized in that when switching a starting gear when the vehicle is stationary, the rest point is approached becomes. Method according to at least one of the claims 1 to 8, characterized in that during a switching operation during drive the clutch open and then the previously taught when engaged in starting gear vehicle and stored clutch waypoint with low torque transmission is approached. Method according to at least one of the claims 1 to 9, characterized in that a Zupunkt, wherein the clutch is fully engaged, over one Movement of the clutch in the closing direction until reaching an end position at which the path change of the clutch during the closing process assumes the value zero, is taught. Method according to at least one of the claims 1 to 10, characterized in that a preselected Contact point, at which the friction partners of the coupling touch, depending on the previously learned pickup point is determined. Device for controlling a clutch, in particular a friction clutch in a drive train of a motor vehicle, via an internal combustion engine with a transmission is connected, characterized characterized in that a control device for driving the clutch means for detecting and processing engine, clutch and control-relevant data as well as for the storage thereof Having clutch waypoints, by means of a method according to a of claims 1 to 11 is feasible.