DE10346885B4 - Method for operating a commercial vehicle - Google Patents

Abstract

method for operating a motor vehicle, in particular a utility vehicle or a truck, with a drive train (10), with a in the drive train (10) arranged automatically actuated starting clutch (17) and an associated Control device (16), wherein the starting clutch (17) in dependence of operating parameters of the drive train (10) for warranty a follow-up torque (M_NF) about a clutch release path (Ks_ausrück) is disengaged and the tracking torque (M_NF) between the moment of the fully disengaged clutch (17) and the moment of complete engaged clutch (17), wherein the Nachführmoment (M_NF) depending an engine braking torque is determined, characterized in that upon first detection of actuation of a service brake (22) of the vehicle a short-term opening pulse (BB_Peak) for the starting clutch (17) is generated.

Description

The The invention relates to a method for operating a commercial vehicle, in particular a truck, with one in the drive train arranged automated actuated Starting clutch according to the preamble of patent claim 1.

From the German patent application DE 199 49 204 A1 is a motor vehicle with a drive train known with an arranged in the drive train automatically actuated (start) clutch and an associated control device, the (start) coupling in response to operating parameters of the drive train to ensure a Nachführmomentes, ie a clutch torque to a Kupplungsausrückweg is disengaged and thereby the Nachführmoment between the moment of the fully disengaged and the moment of the fully engaged clutch, wherein the tracking torque is determined in response to an engine braking or engine drag torque.

It It has been found that with this solution the automated coupling, especially in a commercial vehicle, not in all driving situations on time and / or fast enough and / or at the right time open Consequently, there are situations in which the drive motor stall can be.

Of the The invention is therefore based on the object, a method for operation a motor vehicle, in particular a commercial vehicle or a Truck, with an automated driveline included Start clutch to be designed so that in every driving situation kill of the engine is prevented.

Is solved this object by a method with the specified in claim 1 Features.

at the engine braking torque is in particular a braking torque of the engine and / or an additional Engine braking system. Especially for commercial vehicles and trucks becomes frequent in overrun the engine with its braking torque and possibly an additional one Brake transmission for braking or maintaining the speed used. The engine braking torque can be increased by lifting the Abgasgegendrucks means of an exhaust valve and / or by control the gas exchange valves or an additional valve. The drive motor, which is, for example, an internal combustion engine, is not flammable in this state and needs some Time until the ignitability is restored.

Becomes on wet, slippery or slippery roads in addition to the activated engine brake from the driver nor the service brake, especially one of a Brake assistants and axle modulators extremely fast operated electro-pneumatic wheel brake, actuated, it can be used to block at least one drive wheel or a Drive axle come. This is the automated start-up clutch opened at the wrong time, the non-combustible engine dies the speed of the (now ignitable) engine is decreasing or decreasing through the blocking drive wheel or the blocking drive axle below a critical value, which also causes death of the engine leads.

According to the invention, it is proposed that upon first detection of the operation of a service brake of the vehicle a momentary opening pulse for the Starting clutch is generated.

Thereby, that always only the smallest, just necessary clutch transmission torque is set is guaranteed that the engine braking torque at any time reliable from the drive motor on the Starting clutch and the other drive train on the drive wheels of the Motor vehicle transmitted and thus can be used for braking. On the other hand can off the engine speed and the known relationship between engine speed-dependent engine braking torque and engine speed to the size of the current one Engine braking torque closed and the automated starting clutch at the right time, when the engine is again flammable and the engine speed is not yet has fallen below a critical value, to be opened.

By the inventive method is about it It also ensures that even with an ABS braking (braking with use of the anti-lock braking system) or during a blocking braking (braking with at least one blocking drive axle) of the drive motor not stalled becomes. The starting clutch can due to the small, yet to be set remaining Kupplungsausrückweges open fast enough be, because by the short-term, the first recognition of the activity a service brake of the vehicle generated opening pulse (hereinafter also referred to as "opening peak") for the starting clutch a corresponding time gain arises.

In a further development of the invention according to claims 2 and 3 it is proposed that, moreover, the opening pulse causes a halving of the current setpoint value of the clutch release path and that, finally, in the presence of an opening criterion, the opening pulse is at least partially maintained and otherwise the starting clutch is closed again to ensure the Nachführmomentes.

Thereby on the one hand the for the subsequent recognition of the gradient criteria (gradient of the Brake pedal travel, gradient of engine or transmission input speed) needed Time must be saved and on the other hand does not have the startup clutch permanently with a low transferable moment be operated, which contributes significantly to material conservation.

Of the comparatively slow actuator for actuating the automated starting clutch makes at the short, by the opening pulse triggering time did not make a significant difference when previously the starting clutch was closed because the torque tracking still has not addressed and therefore none of the criteria for opening the Starting clutch fulfilled is. Is however an opening criterion Fulfills, then adds it is the opening pulse in the case of the criterion for the Bremsspedalweggradienten even without delay, so that a corresponding Time to open the Starting clutch is created.

Farther is according to claim 4, the Nachführmoment is proposed calculated from the engine braking torque and a safety factor. This ensures that in overrun and even in unfavorable influences the starting clutch is not for longer Time slipped and damaged by excessive thermal load or destroyed becomes.

at a preferred embodiment of the method according to claim 5 it is proposed that the starting clutch after a switching operation is not is completely closed, but in a position to guarantee of the follow-up torque is brought or remains. This results in a discharge for the Clutch adjustment device and a reduction of wear, there between two switching operations the starting clutch not fully closed and then again the tracking torque opened accordingly must become.

To Another proposal of the invention according to claim 6, the determination of the follow-up torque dependent on of the engine braking torque started when the gradient of the brake pedal travel in the direction of an increase exceeds a threshold. The gradient, so the rate of change, of the brake pedal way gives information about it, what kind Braking it is. In a normal, foreseen (soft) Braking actuated As a rule, the driver carefully and doses the brake pedal with a correspondingly small rate of change, so that no wheel is blocked by the braking. In such a Case of soft braking must be the automated starting clutch Not open because the risk of engine stalling does not exist.

in the In contrast, in case of unforeseen (hard) braking, For example, to avoid a rear-end collision, the driver depresses the brake pedal fast and with great Force, i. with high rate of change, actuate, which usually blocks one or more wheels. In the case of one (hard) ABS or blocking braking must be the automated starting clutch to be opened not to stall the drive motor.

The So that means based on the rate of change the brake pedal operation with big ones Safety can be concluded whether a soft or a Hard braking is imminent and therefore whether the automated starting clutch open must or not. Building on empirical values is therefore advantageously a threshold for the gradient of the brake pedal operation set an assessment of the upcoming braking and so the decision allows whether the automated starting clutch needs to be opened.

Especially It is advantageous if according to claim 7 the threshold for the gradient of the brake pedal travel from the engine or transmission input speed dependent is because there are critical and non-critical speed ranges. In critical Speed ranges there is a risk of engine stalling, so that there the automated starting clutch must be opened. In uncritical Speed ranges, however, this risk does not exist, so that the Starting clutch can remain closed.

Analogous this is it according to claim 17 also advantageous that the tracking of the clutch torque is omitted if in uncritical gear ratios or uncritical Engine speeds is driven.

Comparable behave It is with the gradient, ie the rate of change, the Engine or transmission input speed, so that in a preferred method according to claim 8 the determination of the tracking torque depending on the Engine braking torque is started when the gradient of the engine or transmission input speed exceeds a threshold. Again, there is the Advantage in that the real danger of engine stalling in an early one Stage is detected and by opening the automated startup clutch can be safely prevented.

Furthermore it is advantageous that the coupling is opened immediately completely according to claim 18, when the gradient of the engine or transmission input speed in the direction a decrease exceeds a threshold or if the gradient of the brake pedal travel in the direction of an increase exceeds a threshold, to be reliable an engine stall to avoid.

Also It is also particularly advantageous if, according to claim 9, the threshold for the Gradients of the engine or transmission input speed from the engine or transmission input speed is dependent, with the already mentioned Benefits.

Farther is in the claims 10 and 11 proposed that the motor braking torque dependent Nachführmoment additionally depends on the vehicle speed and that of the Engine braking torque dependent Nachführmoment with increasing vehicle speed to increasingly larger values is set. This has higher Speeds smaller clutch opening paths result and can be accepted because with increasing speed the danger of stalling becomes smaller or disappears completely and you do without the torque tracking to a corresponding extent can. For the protection of the aggregates involved is very important.

to Gentle on the material even if, according to claim 19 the threshold for the gradient of the engine or transmission input speed and / or the threshold for the gradients of the brake pedal travel are speed-dependent and uncritical Speeds a torque tracking omitted.

advantageous Embodiments of the invention will become apparent according to claims 12 and 15 also, if in addition to tracking the Kupplungsausrückweges if there is one Criterion, a pilot control of the clutch torque takes place, namely also depending on the Engine braking torque. This ensures that the tracking torque a minimum value does not fall below and on the one hand a possible Carefully transfer engine braking torque and on the other hand, the engine in an ABS or blocking braking not stall becomes. In addition, one becomes unnecessary high actuator load avoided, as the clutch and rare less open must become.

Further advantageous embodiments of the invention are in further claims, the Description and the figures indicated.

The Invention will now be described with reference to an embodiment with the aid explained the drawing.

there demonstrate:

1 a detail of a drive train of a motor vehicle in a basic block diagram similar representation,

2a a flowchart of a method for the precontrol of a clutch release path,

2 B a flowchart of a method according to the invention for determining a Kupplungsnachführmomentes and

2c a diagram showing the qualitative relationship between a torque to be transmitted and the Ausrückweg at a starting clutch ("clutch characteristic").

The according to the invention is particularly suitable for operating a motor vehicle, in particular a commercial vehicle or a truck, with one in the drive train arranged automated actuated Starting clutch.

According to 1 has a powertrain 10 a motor vehicle, not shown, in particular a commercial vehicle or a truck, via a drive motor 11 , which by a control device 12 is controlled. The control device 12 stands with not shown actuators, such as a throttle plate actuator, and sensors, such as speed sensors, in signal communication. Furthermore, one with the drive motor 11 related engine braking system 28 present, which also with the control device 12 is in signal connection.

The control device 12 also features a power actuator designed as an electronic drive or accelerator pedal 13 in signal connection, by means of which a driver to be dispensed torque of the drive motor 11 can adjust. The control device 12 can from recorded variables further operating variables of the drive motor 11 , For example, the actual output torque of the drive motor 11 to calculate.

The drive motor 11 is over an output shaft 14 with an automatically actuated starting clutch 17 connected, the starting clutch 17 in turn about another wave 26 with a gear 15 Being as a manual or automated Gear shift or is designed as an automatic transmission and by a control device 16 is controlled. The automatically actuated starting clutch 17 is powered by a clutch actuator 25 operated, which is also from the controller 16 is controlled.

The gear 15 is by means of a drive shaft 18 with a axle drive 19 connected, which in a known manner the output torque of the drive motor 11 about side waves 20 on powered vehicle wheels 21 transfers.

At the vehicle wheels 21 are braking devices 22 a service brake arranged, which of a control device 23 be controlled. The braking devices 22 the service brake are designed as conventional, pneumatic, electrohydraulic or electric motor operated wheel brakes, the necessary signal and / or supply lines are not shown. The control device 23 stands with a brake pedal 24 in signal connection, by means of which the driver of the braking devices 22 can apply the service brake applied and thus acting on the motor vehicle braking torque.

This is the position of the brake pedal 24 detected by a sensor, not shown, and to the control device 23 which then transmit the braking devices 22 the service brake controls accordingly. The control device 23 but can the braking devices 22 the service brake also independent of the position of the brake pedal 24 For example, upon request of the controller 12 or the controller 16 go, drive.

In the brake systems 22 the service brake are integrated speed sensors, not shown, by means of which the control device 23 a speed of the vehicle wheels 21 can capture. From these speeds, the speed of the motor vehicle can be determined. The service brake with the associated brake devices 22 and the associated control device 12 may be designed via known operating modes such as ABS (anti-lock braking system), ASR (traction control) or an anti-slip device.

The engine brake system 28 For example, by influencing the charge exchange, usually by raising the exhaust backpressure by means of an exhaust flap, activated or by an intervention in the high pressure loop, for example by controlling the gas exchange valves or an additional valve (clocked or unclocked decompression brake). In addition, the engine brake system can 28 one between engine 11 and starting clutch 17 switched, generally multi-stage hydrodynamic brake (retarder) include.

The control devices 12 . 16 and 23 are connected to each other via a serial bus connection 27 , for example via a CAN bus (Controller Area Network), in signal connection. This can be detected variables, such as the speed of the vehicle wheels 21 , exchanged or requirements for one of said or to another control device, for example, the setting of a specific braking torque from the control device 12 of the drive motor 11 to the control device 23 the braking devices 22 to be sent. The braking devices 22 the service brake are at least indirectly by the controller 12 of the drive motor 11 driven.

A method for pilot control of a Kupplungsausrückweges A according to 2a starts in the block 30 , A feedforward control on a specific clutch release travel A or on a specific follow-up torque corresponding to this clutch release travel A takes place when a triggering criterion described in this respect, which is described below, is fulfilled.

In the following query block 32 it is checked if the service brake 22 ( 1 ) is pressed. In next query block 34 it is checked whether in the control device 12 for the service brake 22 the operating mode ABS (antilock braking system) is activated. When the operating mode ABS is activated, in a subsequent query block 36 queried if the engine braking system 28 ( 1 ) is activated. With the engine brake system activated 28 will be in a subsequent query block 38 checked if the engine speed is less than 1250 1 / min. If this is the case, in a subsequent block 40 set a value for a Kupplungsausrückweg A.

Is in the query block 34 found that for the service brake 22 the operating mode ABS (antilock braking system) is not activated, is in a subsequent query block 42 checked if the engine speed is less than 1500 1 / min. If this is the case, in the following block 40 branches and set a value for a clutch release path A. In one on the block 40 subsequent block 44 the method for pilot control of a clutch release path A is terminated.

The flowchart of the method for determining a Kupplungsnachführmomentes M_NF or a Nachführmoment M_NF corresponding Kupplungsausrückweges Ks_ausrück according to 2 B starts in a block 50 , In a subsequent block 52 is calculated as large, the current minimum transmission torque Mmin of the starting clutch 17 ( 1 ), so that any current braking torque of the engine 11 still safe on the starting clutch 17 on the gearbox 15 and finally to the vehicle wheels 21 can be transferred.

This is done in a block 54 determines the engine speed nMot and the result to the block 52 and to a block 56 transmitted. Furthermore, in the block 56 the current engine braking torque as a function of the block 54 determined motor speed nMot and a safety factor K_M_MB and determined to the block 52 transmitted.

The Engine braking torque is assumed to be engine speed-dependent, namely linear or square between 500 Nm at an engine speed nMot of 1000 1 / min and 1000 Nm at 2000 1 / min. The safety factor K_M_MB, for example, assuming a value of 1.5, is variable. He is dimensioned so that the engine braking torque transmitted safely can be and considered also uncertainties regarding the knowledge of the engine torque and the clutch characteristic.

In some cases, it may be useful, instead of or in addition to the engine speed nMot mentioned here, to determine and possibly take into account the possibly easier to determine transmission input speed, and possibly also the gradient of the engine or transmission input speed, by setting a respective associated threshold value becomes. It can also be useful that the respective threshold value can be changed and, for example, increased with increasing engine or transmission input speed. The associated algorithm does not run within this flowchart 2 B but in a separate routine.

Between in block 52 calculated current minimum transmission torque Mmin and the engine speed nMot a linear or quadratic relationship is assumed, or the determination of the current minimum transmission torque Mmin is analogous to the determination of the engine speed dependent engine braking torque in the block 56 as described above, wherein the thus determined engine braking torque is still multiplied by the safety factor K_M_MB.

When first detecting the operation of a service brake 22 ( 1 ) of the vehicle and when the gradient of the brake pedal travel exceeds an associated threshold value, in a subsequent block 58 a momentary opening peak (opening impulse) BB_Peak for the starting clutch 17 generated. This is done in a block 60 the respective state of the service brake 22 and the engine braking system 28 queried and the result to the block 58 transmitted. If the engine brake system 28 is activated, is at the transition of the service brake 22 from the status "not actuated" to the status "actuated" in the block 60 set a flag. At this time, in the block 58 for a certain short time, for example for 100 ms, also set a flag BB_Peak.

The gradient of the brake pedal travel leads to a reaction when the associated threshold value is exceeded (starting clutch 17 immediately fully open), as is the case with braking with the use of ABS. In this case, the threshold value for the gradient of the brake pedal travel can be variable and dependent on the engine or transmission input rotational speed; It is increased, for example, with increasing engine or transmission input speed. The associated algorithm does not run within this flowchart 2 B but in a separate routine.

In a subsequent decision block 62 is queried, whether in the previous block 58 the flag BB_Peak has been set. If this is true, it will be in a subsequent block 64 branches in which the in the block 52 certain minimum transmission torque Mmin halved and the result to a subsequent block 66 is transmitted. The setting of the flag BB_Peak, together with the consequent halving of the minimum transmission torque Mmin, causes a short activation of the clutch actuator 25 ( 1 ) in the direction of a further open starting clutch 17 , whereby the reaction time is significantly reduced during braking with the use of ABS.

The flag BB_Peak is set, for example, for a duration of 100 ms when the service brake is actuated for the first time and causes the current torque tracking torque Mmin to be halved in order, on the one hand, to detect the gradient criteria (see block 60 ) Save time and on the other hand, the startup clutch 17 not having to operate permanently with a low transmittable torque.

The comparatively slow actuator for actuating the automated starting clutch 17 , the actor 25 ( 1 ), does not make a significant difference in this short driving time, if previously the starting clutch 17 was closed, because the torque tracking has not yet addressed and therefore none of the above criteria for opening the starting clutch 17 is satisfied. However, if such an opening criterion is block 60 If it is satisfied, then it adapts to the opening peak BB_Peak, in the case of the criterion for the brake pedal travel gradient even without delay, so that a corresponding time gain for opening the clutch 17 arises.

Is the query in the decision block 62 that in the previous block 58 the flag BB_Peak has not been set, so it goes directly into the following block 66 branched.

In the block 66 the determination of a provisional follow-up torque M_Nf takes place. This is done first in a block 68 a through the power actuator 13 ( 1 ) set by the driver accelerator pedal torque M_FP and a safety factor for the transmission torque K_M_FP determined and the respective result the block 66 transmitted.

In the block 66 there is a maximum choice between the one in the block 52 and possibly in the block 64 certain minimum transmission torque Mmin on the one hand and the product of the accelerator pedal torque M_FP and the safety factor for the transmission torque K_M_FP on the other. The larger of the two values, either the minimum transmission torque Mmin or the product M_FP · K_M_FP from the accelerator pedal torque M_FP and the safety factor K_M_FP, is referred to as the preliminary tracking torque M_Nf to a subsequent block 70 passed.

In a block 72 For example, the vehicle speed v, a lower threshold v_min for the vehicle speed v and a vehicle speed factor K_v are determined, and the results are sent to the block 70 forwarded.

The driving speed v is usually already present in at least one of the control units and can be queried for example via the CAN bus. The vehicle speed factor K_v is a freely selectable proportionality factor that has a linear or a quadratic relationship between a vehicle speed-dependent magnification factor KV_v (block 70 ) and the speed v: KV_v = K_v · v or KV_v = K_v · v · v.

Below the lower threshold value v_min for the vehicle speed v, clutch tracking no longer takes place, the starting clutch 17 is then completely closed.

It may be useful to set an upper threshold for the vehicle speed v, from which the starting clutch 17 is completely closed. For example, when driving on a highway no clutch tracking takes place, because in such a driving situation enough time remains, the starting clutch 17 To open at the right time and thus the risk of engine stalling, for example, due to a blocking or ABS braking, is not given.

In the present embodiment, no discrete upper threshold for the speed v is established. However, the magnification factor KV_v, which assumes values greater than one above the lower threshold value v_min, causes an increase in the tracking torque and thus in conjunction with a clutch characteristic ( 2c ) that, for example, from a speed of 30 km / h, the torque tracking with increasing speed is increasingly overridden.

In the block 70 First, the vehicle speed-dependent magnification KV_v for that in the block 66 determined provisional follow-up torque M_Nf determined. Below the block 72 determined lower limit value v_min this vehicle speed-dependent magnification KV_v takes the value one, above it a value greater than one, in linear or quadratic dependence on that in the block 68 certain driving speed factor K_v.

Subsequently, in the block 70 a new, final tracking torque M_NF determined by the block 66 determined provisional Nachführmoment M_Nf multiplied by the driving speed-dependent magnification Kv_v, so that applies to the final tracking torque M_NF: M_NF = M_Nf · KV_v.

The dependent on the engine braking torque Nachführmoment M_NF is thus increasing with increasing vehicle speed v larger values set.

This final tracking torque M_NF applies to operation with an adhesive starting clutch 17 ( 1 ), that is, when no switching, stopping or starting process takes place or when driving in uncritical gear ratios (for example, in a high gear) or at non-critical engine speeds (for example, more than 1250 1 / min), ie if in such grades or is driven at such engine speeds, where the risk of engine stalling is very low or not. Uncritical gear ratios or engine speeds are to be determined as a function of the vehicle and the time behavior of the engine brake and flow in the form of the safety factors K_M_MB (Block 56 ), K_M_FP (block 68 ) and the vehicle speed factor K_v (block 72 ) as well as the lower threshold for the driving speed v_min (block 72 ) in the in the flowchart of 2 B illustrated algorithm.

In a subsequent block 74 is a setpoint Ks_ausrück for the Ausrückweg of the starting clutch 17 ( 1 ) as a function of the block 70 calculated final tracking torque M_NF calculated.

2c shows a diagram based on a "clutch characteristic" 84 the relationship between a torque to be transmitted and the Ausrückweg a start clutch, here the start clutch 17 ( 1 ). On an abscissa 80 with the clutch release path (in mm or 0 to 100%) is on an ordinate 82 the torque to be transmitted, in general, the output torque of the drive motor to be transmitted 11 or a braking torque to be transmitted, applied.

The for each starting clutch 17 typical clutch characteristic 84 is known and stored for example in a characteristic field, so that at a known and transmitted output torque 82 of the drive motor 11 on the set for this Kupplungsausrückweg 80 can be deduced.

In the diagram of 2c is used to determine the setpoint Ks_ausrück for the release travel of the starting clutch 17 ( 1 ) for the clutch torque to be transmitted on the ordinate 82 that in the block 70 determined final tracking torque M_NF used, for example, a value 86 accepts. Based on the clutch characteristic 84 then results for the Nachführmoment to be transmitted M_NF on the abscissa 80 a certain value 88 for the Kupplungsausrückweg to be set, in the block 74 of the 2 B corresponds to the setpoint Ks_ausrück.

In a block 76 of the 2 B the method for determining a clutch follow-up torque is terminated. The determination of the Kupplungsnachführmomentes takes place constantly. The tracking of the block 74 Calculated Kupplungsausrückweges Ks_ausrück depending on the engine braking torque occurs when the calculated value is greater than the piloted, in the method according to 2a certain clutch release travel (A).

Claims (19)

Method for operating a motor vehicle, in particular a utility vehicle or a lorry, with a drive train ( 10 ), with one in the drive train ( 10 ) arranged automatically actuated starting clutch ( 17 ) and an associated control device ( 16 ), wherein the starting clutch ( 17 ) as a function of operating parameters of the drive train ( 10 ) to ensure a Nachführmomentes (M_NF) is disengaged by a Kupplungsausrückweg (Ks_ausrück) and the tracking torque (M_NF) between the moment of the fully disengaged clutch ( 17 ) and the moment of fully engaged clutch ( 17 ), wherein the follow-up torque (M_NF) is determined as a function of an engine braking torque, characterized in that the first time the actuation of a service brake ( 22 ) of the vehicle a short-term opening pulse (BB_Peak) for the starting clutch ( 17 ) is produced. Method according to claim 1, characterized in that that the opening pulse (BB_Peak) halves the current setpoint of the clutch release path (Ks_ausrück) causes. Method according to Claim 1 or 2, characterized in that, when an opening criterion is present, the opening pulse (BB_Peak) is at least partially maintained and otherwise the starting clutch ( 17 ) is closed again until the follow-up torque (M_NF) is guaranteed. Method according to claim 1, characterized in that that the tracking torque (M_NF) from the engine braking torque and a safety factor (K_M_MB) is calculated. Method according to claim 1 or 4, characterized in that the starting clutch ( 17 ) is not completely closed after a switching operation, but is brought into a position to ensure the Nachführmomentes (M_NF) or remains. Method according to one of claims 1, 4 or 5, characterized that the determination of the Nachführmomentes (M_NF) depending of the engine braking torque is started when the gradient of the brake pedal travel in the direction of an increase exceeds a threshold. Method according to Claim 6, characterized that the threshold for the gradient of the brake pedal travel from the engine or transmission input speed dependent is. Method according to one of claims 1 or 4 to 7, characterized characterized in that the determination of the Nachführmomentes (M_NF) depending on the engine braking torque is started when the gradient of engine or transmission input speed exceeds a threshold. Method according to claim 8, characterized in that that the threshold for the gradient of the engine or transmission input speed from the engine or transmission input speed is dependent. Method according to one of claims 1 or 4 to 9, characterized characterized in that the follow-up torque (M_NF) dependent on the engine braking torque additionally depends on the vehicle speed (v). A method according to claim 10, characterized ge indicates that the engine braking torque dependent Nachführmoment (M_NF) with increasing vehicle speed (v) is set to increasingly larger values. Method according to one of claims 1 or 4 to 12, characterized characterized in that a pilot control on a Kupplungsausrückweg (A) or on a Nachführmoment corresponding to this Kupplungsausrückweg (A) (M_NF), if any trigger criterion Fulfills is. A method according to claim 12, characterized in that the triggering criterion for the precontrol of the Kupplungsausrückweges (A) is met, when in an anti-lock brake system, the engine brake system ( 28 ) and a service brake ( 22 ) and the engine speed is less than or equal to 1250 rpm. A method according to claim 12, characterized in that the triggering criterion for the precontrol of the Kupplungsausrückweges (A) is met, when in an anti-lock brake system, a service brake ( 22 ) and the engine speed is less than or equal to 1500 rpm. Method according to one of claims 12 to 14, characterized that the pilot control of the clutch torque in addition to tracking the Kupplungsausrückweges (A) depending on Engine braking torque occurs. Method according to one of claims 1 or 12 to 15, characterized characterized in that the tracking of the clutch torque (M_NF) as a function of the engine braking torque occurs when the tracking torque (M_NF) is larger as the clutch torque already set by the pilot control, that the clutch release path (A) corresponds. Method according to one of claims 1 to 16, characterized in that the tracking of the clutch torque (M_NF) is omitted when the engine braking system ( 28 ) is not actuated, or during a start, shift or stopping operation or when driving in uncritical gear ratios or at uncritical engine speeds. Method according to one of claims 1 to 17, characterized that the triggering criterion for the complete opening of the Clutch is met, when the gradient of the engine or transmission input speed in the direction a decrease exceeds a threshold or when the gradient of the brake pedal travel toward an increase Threshold exceeds. Method according to claim 18, characterized that the threshold for the gradient of the engine or transmission input speed and / or the threshold for the gradient of the brake pedal travel are speed-dependent.