DE10221262A1 - Process to regulate operation of automotive automatic gearbox and clutch reduces engine speed while changing down gear - Google Patents

Abstract

In an automotive process to operate an automatic gearbox and clutch, during deceleration the gearbox automatically changes down from e.g. a third gear to a second gear. The change is accompanied by disengagement and re-engagement of the clutch. While the clutch is disengaged, the automatic system esp. effects a brief reduction in engine speed, to effect a steady reduction in vehicle speed.

Description

The invention relates to a method for controlling and / or regulating an automatic based clutch and / or an automated transmission of a vehicle, in particular of a motor vehicle in which a torque reduction during a Disengagement phase is carried out.

Methods for controlling and / or regulating an au are from vehicle technology automated clutch and / or an automated transmission of a vehicle known. Through an automated clutch or an automated Ge drives, in particular, the disengagement process is automated, so that a driver of the vehicle no longer has to operate the clutch.

In the known method, however, particularly in the case of a train upshift gene, the duration of the disengagement phase is relatively long. Be Known procedures may occur that the Auskup pelphase a thrust torque of the engine on the wheels of the vehicle still  is transmitted, which in particular with regard to the life of a clutch lung is unfavorable.

In order to enable a gear change in a vehicle, the be Known procedures abge the torque transmitted from the engine to the wheels builds. This torque reduction of both the engine torque and the transmission clutch torque is triggered automatically. For the driver, this can come very surprisingly, especially when full load switching operations occur be performed. This can cause a relatively strong jerk or vibrations lead on the vehicle, which significantly affects the driver's perception flows and is perceived as unpleasant.

The present invention is therefore based on the object of a method of to create the type mentioned, in which the jerk at given degradation time of the clutch torque is kept as low as possible and the excitation and transmission of drive train vibrations to the wheels is avoided that will.

This object is achieved by the features of the claim 1 solved.

Accordingly, the torque reduction is possible in the method according to the invention Lich carried out evenly, so that in particular vibrations of the An drive train can be avoided. Through targeted control of the transferable  Ren clutch torque, it is possible to meet this requirement. To suppress Covering back vibrations z. B. the drive train, it is therefore useful especially the rotating mass of the engine, e.g. B. right at the beginning of the moments Disassembly phase, uncoupling from the drive train. This can be done in particular by a quick reduction of the clutch torque can be achieved.

Therefore, according to a development of the invention, it is provided that during the decoupling phase, the clutch torque according to a suitable function is broken down. So that the transition from sticking to slipping in the Coupling can be suppressed in an advantageous manner right from the start.

It is particularly advantageous if slip occurs at the start of the disengaging phase is permitted on the clutch, as is the case with another training of Invention can be provided.

Through a carefully chosen time course of the transferable dome vibrations in the drive train are minimized. By Si mulations has shown that in particular a temporally parabolic Ab Construction of the clutch torque is particularly advantageous for this. Therefore, according to Another development of the invention provides that the clutch motor ment preferably first by a parabolic function and then is given by a linear function. Of course you can too other suitable functions for the timing of the clutch torque can be provided in order to further optimize the method according to the invention.  

It is particularly advantageous if the aforementioned measures are combined with one another when the clutch torque is reduced. This means that slip at the clutch is permitted at the beginning of the torque reduction and then a temporally parabolic reduction of the clutch torque follows. The water parabolic reduction of the clutch torque can after a certain decay time τ _{R of} the jerky vibrations continuously and differentially in a linear course, as seen in an advantageous development of the invention. This combination further improves driving comfort in the vehicle.

Another development of the present invention can provide that the temporal course of the clutch torque is predetermined by an initial clutch torque and by the gradient of the initial clutch torque. Preferably, the initial clutch torque can be determined by the following equation:
T _{c, 0} = α. (T _{e, 0} - J _e . _{E, 0} ), where
T _{c, 0} = initial clutch torque,
α = ratio of transferable clutch torque and dynamic engine torque,
T _{e, 0} = initial engine torque,
J _e = moment of inertia of the motor,
_{e, 0} = angular acceleration of the motor at the start of the decoupling process.

It has been shown that the ratio α is preferably in the range of approximately 1.0 should be up to 1.025. Of course, other values can also be used become.

The following equation can be given for the slope of the initial clutch torque:
_{c, 0} = β. _{c, max} , where
_{c, 0} = slope of the initial clutch torque,
β = ratio of the start and end degradation rate of the transmitted clutch torque,
_{c, max} = maximum slope of the clutch torque.

It has been shown that the ratio β should preferably be in the range from 0.3 to 0.6. Of course, other values can also be used here. The aforementioned relationships or equations can be used to minimize vibrations during disengagement. In the equations, J _e denotes the moment of inertia of the motor and _{e, 0} the angular acceleration of the motor at the beginning of the decoupling phase. α is the ratio of transferable clutch torque and dynamic engine torque at the start of the disengagement phase, where β is the ratio of the start and end degradation rate of the transferable clutch torque. The aforementioned conditions for α and β lead to a ruckmi-minimized disengagement in the method according to the invention. The jerk can be defined as the time derivative of the vehicle acceleration, so that the loss of comfort is less, the smaller the amount of the time derivative of the vehicle acceleration. The aforementioned equations can also be suitably varied or changed in the method according to the invention.

Another embodiment of the present invention can provide that a time-dependent course of the clutch torque is described by the following equations:
T _c (t) = T _{c, 0} + (s ₀ + bt) .t for t ≦ τ _g and
T _c (t) = c + s. (T - τ _g ) for t <τ _g

Here, t is the time from the start of the decoupling phase and T _{c, 0 is} the transmittable torque to which the clutch is set at the start of the decoupling phase. The slope of the linear engine torque reduction and thus the slope at the beginning of the engine torque reduction are designated with s. Should be since both T _c, that the temporal course of the clutch torque, as well as _c, that is the slope of the clutch torque profile during the transition from the parabolic curve for linearly continuous, should b and c are preferably the following conditions ge nügen:

Of course, others can also be used in the method according to the invention appropriate conditions are used.

It is also possible for the slope s of the linear torque reduction to be applied in the vehicle during fine tuning. Dependencies on engine torque and gear can also be taken into account. In order to provide the simplest possible calculation formulas for s ₀ and T _{c, 0} , the following approaches are suggested as examples:
s ₀ = β.s,
T _{c, 0} = α. (T _{e, 0} - J _e . _{E, 0} )

The angular acceleration of the motor at the beginning of the decoupling is indicated with _e . In the formula given here, values of 0.8 to 1.1 were preferably given for α, which can be varied in steps of 0.05. Values from 0 to 1 are given for β, which can be varied in steps of 0.2. Of course, other value ranges or other steps are also possible here. The initial engine torque T _{e, 0} was preferably set to 100 Nm. Variations are also possible with this value.

It has been shown that preferably in the method according to the invention the clutch should be at the slip limit at the beginning of the torque reduction and the initial slope of the torque reduction approximately between 30 to 60% of the Final slope should be. These values give the inventions process according to the invention an optimal torque reduction, in which the Vibrations of the drive train can be minimized. This is because a early decoupling of engine and drive train in the invention Procedure is made possible.

Due to the optimal interplay of temporally non-linear and linear Mo vibrational excitation is practically elimi in the beginning niert and a largely uniform torque reduction achieved. In advantageous In the method according to the invention, the number of application pairs becomes parameters significantly reduced, making coordination in the vehicle easier becomes.

Another development of the present invention can provide that Optimizing the method according to the invention uses a simulation model becomes. In the simulation model, the turning masses of the Engine, the clutch disc, the gearbox and the vehicle, as well as the Elasti The quality and damping of the drive shafts and the clutch are taken into account. Of course, other suitable ones can also be used in the simulation model Operating variables or parameters are used.  

The driving resistance torque can be smaller than that in the simulation model Engine torque so that an acceleration situation is simulated can. The initial conditions can be chosen so that the drive strand of the vehicle does not vibrate and the clutch adheres. For the engine and the clutch torque can implement different reduction profiles tated, so that different strategies of engine torque reduction with the simulation model can be examined.

The most important parameters of the vibration system are preferably the _{rotating mass of} the vehicle J _Fzg = 0.75 kgm ² , the rotating mass of the transmission J _Get = 0.025 kgm ² , the rotating mass of the motor J _Mot = 0.165 kgm ² , C _drive = 33 Nm / rad and d _drive = 1 Nms / rad.

This results in the period for the jerking between the engine and the gearbox has a value of 675 ms (1.5 Hz) and the Jerk between the gearbox against the vehicle a value of 170 ms (5.9 Hz).

The vehicle acceleration can be differentiated in the simulation model, whereby one can make a statement about the present jerk in the vehicle holds. The negative maximum value of the jerk provides a decisive criterion the evaluation of the different strategies.  

Another development of the present invention can provide that the clutch slip in the torque reduction at the beginning of the decoupling phase is achieved by a KME factor of the global strategy being set to a value z. B. is set less than 1. In order to also take into account the proportion of the engine torque that is included in the self-acceleration of the engine, the following approach can be taken:
M _Kup = KME. (M _Mot - J _Mot . _Mot ), where
M _Kup = clutch torque,
KME = factor of global strategy,
M _Mot = engine torque
J _Mot = moment of inertia of the motor,
_Mot = angular acceleration of the motor.

It is particularly advantageous if the KME factor during the moment decremented to a value less than 1 until a specified mini mum is reached. Of course, the KME factor can also be used in other ways be reduced and limited.

According to another development of the invention, it can be provided that the gradient of the clutch torque in the linear range depending on the driving situation is determined as a shift comfort parameter. Because the gradient of the clutch motor in the linear range is directly proportional to the jerk maximum together.  

The beginning jump in the reduction of moments together with the initial gra served in the parabolic reduction of the clutch torque determines the size of the first peak in the jerk course.

According to a further embodiment of the present invention, it is conceivable that a situation-independent KME factor and / or a gradient in the linear range proportional torque offset is used. Selbstverständ Lich other suitable parameters in the Ver invention driving can be used.

It is also conceivable that the initial gradient of the clutch torque at at least depending on the course, a constant percentage of the gradient in the linear Be has rich. This is because the level of damping in the drive train is down pending is constant.

With regard to the duration of the parabolic torque reduction, according to one other development of the invention take into account that at the end of parabolic degradation of the excited natural vibrations in the drive train should have sounded so that the subsequent linear torque reduction none causes further jerk increase. Because the natural frequency and the damping degrees in the drive train are constant depending on the gear, the duration of para bolic torque reduction should preferably be a gear-dependent constant.  

With the aforementioned parameters, this can be used to optimize the coordination Parameters also the variation of the moment, the speed and damping tion and adaptation parameters of the clutch characteristic are used to To get statements about the robustness of the strategy. From that you can then derive results for the control implementation.

The method according to the present invention can be used for any kind of Torque transmission systems are used. Particularly advantageous use in electronic clutch management (EKM) and with an automatic gearbox (ASG).

Further advantages and advantageous configurations result from the subordinate sayings and from the descriptive description of the accompanying drawings environment. Show it:

FIG. 1 is a time course of the torque reduction according to the present invention;

Figure 2 shows a time course of the jerk during a Disengaging for two different α-β-pairs.

Fig. 3 is a Konturplott the maximum jerk in an α-β plane for a first parameter variation;

Fig. 4 is a Konturplott the maximum jerk in the α-β plane for a second parameter variation;

Fig. 5 is a Konturplott the maximum jerk in the α-β plane for a third parameter variation;

Fig. 6 is a Konturplott the maximum jerk in the α-β plane for a fourth parameter variation;

Fig. 7 is a Konturplott the maximum jerk in the α-β plane for a fifth parameter variation;

Fig. 8 is a Konturplott the maximum jerk in the α-β plane for a sixth parameter variation;

Fig. 9 is a Konturplott the maximum jerk in the α-β plane for a seventh parameter variation;

FIG. 10 is a Konturplott the maximum jerk in the α-β plane for an eighth parameter variation;

FIG. 11 is a schematic representation of a simulation model of a drive train of a vehicle;

FIG. 12 is three graphs in which various vehicle sizes, while a linear torque degradation in 250 ms are shown;

FIG. 13 is three graphs in which various vehicle sizes are shown in a linear torque reduction in 500 ms;

FIG. 14 is three graphs in which various vehicle sizes are shown in a parabolic torque reduction in 500 ms;

FIG. 15 is three graphs in which various vehicle sizes are shown in a linear torque reduction in 500 ms with slip;

FIG. 16 is three graphs with different vehicle sizes in the inventive torque reduction; and

Fig. 17 is a graphically illustrated measurement result with vehicle data during a switching operation.

In Fig. 1 the curves of the engine torque T _E and the clutch torque T _c are shown during the Disengaging. In order to avoid vibrations in the drive train, slip is permitted at the start of the disengagement phase. This is followed by a parabolic reduction in the clutch torque, which is followed by a linear reduction. In order to prevent the motor from touring away, T _e should drop below T _c towards the end of the decoupling phase, as is indicated in FIG. 1.

In FIG. 2, the jerk is plotted over time, and different in the two diagrams αβ pairs are used. It can be seen from FIG. 2 that α and β have a noticeable influence on the jerk J of the vehicle. In the upper diagram, the values for α are 0.9 and for β are 0. Clear vibrations can be seen at these values. In the lower diagram, the value for α is 1 and the value for β is 0.6. With these values, the excitation of vibrations is practically eliminated.

The initial engine torque in these representations in FIG. 2 is 100 Nm, the driving resistance is 50 Nm, the damping coefficient of the drive train is 1 Nms / rad and the gradient is -350 Nm / s.

In Figs. 3 to 10 are Konturplotts the amount of maximum jerk | _max J | shown in the α-β level for different parameter variations. The white areas are areas in which the maximum jerk is not more than 20 rad / s ³ above the absolute minimum of the respective plot. It is assumed that a change in the jerk by 20 rad / s ^{3 is} still perceived as low by the driver. Typical values of the absolute minima are 260 rad / s ³ at s = -250 Nm / s or 470 rad / s ³ and at s = -350 Nm / s. The α values belonging to the absolute minima are 1.0 or 1.05, the β values are 0.4; 0.6 or 0.8. If you create the intersection of all white surfaces, you get approximately the conditions already specified for almost jerk-minimized disengagement of α and β. Then α should be between 1.0 and 1.025 and β between 0.3 and 0.6.

This means that the clutch at the beginning of the torque reduction Should be the slip limit and the initial slope of the torque reduction 30 to 60% of the final climb should be.

In Fig. 3, the absolute minimum at 267 rad / s ^{3 is} marked by a circle and the star indicates the position of the absolute maximum 930 rad / s ³ . The maximum jerk on the white surface is at most 20 rad / s ³ above the absolute minimum. The engine torque at the start of disengagement is 100 Nm, the driving resistance is 90 Nm, the torque reduction rate in the linear range is -200 Nm / s and the damping coefficient of the drive train is 0.5 Nms / rad.

In Fig. 4, the circle shows the position of the absolute minimum at 264 rad / s ³ and the star shows the position of the absolute maximum at 903 rad / s ³ . The maximum jerk on the white surface is at most 20 rad / s ³ above the absolute minimum. The engine torque at the start of disengagement is 100 Nm, the driving resistance is 10 Nm, the torque reduction rate in the linear range is -200 Nm / s and the damping coefficient of the drive train is 1.0 Nms / rad.

In Fig. 5 the circle again shows the position of the absolute minimum at 267 rad / s ³ and the star shows the position of the absolute maximum at 967 rad / s ³ . The maximum jerk on the white surface is at most 20 rad / s ³ above the absolute minimum. The engine torque at the start of disengagement is 100 Nm, the driving resistance is 50 Nm, the torque reduction rate in the linear range is -200 Nm / s and the damping coefficient of the drive train is 1.0 Nms / rad.

In FIG. 5, the absolute minimum is characterized by the circle at 267 rad / s ³ and the absolute maximum indicated by an asterisk at 1049 rad / s ^3. The maximum jerk on the white surface is at most 20 rad / s ³ above the absolute minimum. The engine torque at the start of disengagement is 100 Nm, the driving resistance is 90 Nm, the torque reduction rate in the linear range is -200 Nm per second and the damping coefficient of the drive train is 1.0 Nms / rad.

In Fig. 7, the circle shows the position of the absolute minimum at 461 rad / s ³ and the star shows the position of the absolute maximum at 962 rad / s ³ . The maximum jerk on the white surface is at most 20 rad / s ³ above the absolute minimum. The engine torque at the start of disengagement is 100 Nm, the driving resistance is 10 Nm, the torque reduction rate in the linear range is -350 Nm per second and the damping coefficient of the drive train is 1.0 Nms / rad.

In Fig. 8, the circle shows the position of the absolute minimum at 461 rad / s ³ and the star shows the position of the absolute maximum at 1027 rad / s ³ . The maximum jerk on the white surface is at most 20 rad / s ³ above the absolute minimum. The engine torque at the start of disengagement is 100 Nm, the driving resistance is 50 Nm, the torque reduction rate in the linear range is -350 Nm per second and the damping coefficient of the drive train is 1.0 Nms / rad.

In Fig. 9, the circle shows the position of the absolute minimum at 462 rad / s ³ and the star shows the position of the absolute maximum at 1092 rad / s ³ . The maximum jerk on the white surface is at most 20 rad / s ³ above the absolute minimum. The engine torque at the start of disengagement is 100 Nm, the driving resistance is 90 Nm, the torque reduction rate in the linear range is -350 Nm per second and the damping coefficient of the drive train is 1.0 Nms / rad.

In Fig. 10, the circle shows the position of the absolute minimum at 264 rad / s ³ and the star shows the position of the absolute maximum at 1823 rad / s ³ . The maximum jerk on the white-white surface is a maximum of 20 rad / s ³ above the absolute minimum. The engine torque at the start of disengagement is 100 Nm, the driving resistance is 90 Nm, the torque reduction rate in the linear range is -200 Nm per second and the damping coefficient of the drive train is 2.0 Nms / rad.

Fig. 11 shows a simulation model of the drive train showing the vehicle. The simulation model includes the rotating masses of the engine, the clutch disc, the gearbox and the vehicle as well as the elasticity and damping of the drive shafts and the clutch.

In Figs. 12 to 16, the engine torque, the clutch torque, the torque of the drive train, the engine speed, the transmission speed, the take-off speed, the vehicle acceleration and the residue are shown over time.

In Figs. 12 and 13, a linear degradation in 250 ms or 500 ms is shown with the condition clutch torque <engine torque. In Fig. 14 a parabolic degradation is indicated in 500 ms with the condition clutch torque <engine torque.

From Fig. 15, a linear torque reduction in 500 ms with slip again be seen. The simulation results for the same torque reduction as in FIG. 14 are indicated there, but in FIG. 15 the KME factor has been decremented to a value below 1.

In Fig. 15 abge is now also built with linear torque reduction with slip. This is achieved by setting the KME factor to a value below 1, as already mentioned. The resulting clutch torque is no longer linear. In this case, the negative jerk is reduced more quickly when the system slips. This is due to the higher natural frequency. For the selected parameters, the negative jerk maximum with slipping torque reduction is greater than with non-slipping torque reduction. The natural vibration decays faster with the same damping with a higher natural frequency, ie with a slipping clutch. The coupling of the clutch torque to the engine torque by means of the KME value leads to considerable engine touring if torque loss slips (KME <1). The gearbox speed, however, is below the output speed, which can be explained by the relaxation of the drive train.

Fig. 16 shows both a parabolic and a linear torque reduction, which are combined with each other. The simulation results show that an almost constant jerk can be achieved during the torque reduction with this approach.

Overall, it can be determined that with linear torque _{reduction, there} is a contribution-related maximum pressure after some time. With a parabolic torque reduction, the largest jerk in terms of amount occurs towards the end. After the late transition of the clutch from sticking to slipping, the jerk is intensified. In a direct comparison of the two degradation curves, the linear torque degradation can do better because the amount of jerk maximum is smaller.

In Fig. 16, a clutch torque jump is provided at the beginning of the torque reduction, which generates the slip and thereby stimulates the higher jerk frequency. This is followed by a parabolic torque reduction on the clutch, where the initial gradient is not 0. After the natural vibrations in the drive train have subsided, a constant gradient of the clutch torque follows. At the end, the engine torque is reduced more quickly than the clutch torque so that the engine cannot travel away and the slip is limited.

The curves shown in FIG. 16 show that an almost constant jerk is achieved during the torque reduction. With a degradation time of 500 ms, the maximum of the deceleration jerk is only -245 rad / s ³ . In contrast, with a linear torque reduction without slip, a deceleration jerk of -325 rad / s ^{3 is} generated. The deceleration jerk can thus be reduced by approximately 25% in the method according to the invention. In addition, the torque reduction time can be significantly reduced with the method according to the invention, namely by approximately 25%.

FIG. 17 shows a full-load upshift process from the second to the third gear. In this shifting process, the clutch is suddenly opened when the engine torque is at a standstill and the gear change is initiated at the same time. The torque builds up after the gear change in accordance with a suitable engagement strategy, preferably through sporty engagement. It is clear from FIG. 17 that the duration of the switching process can be reduced to approximately 340 ms in the method according to the invention.

The claims submitted with the application are drafted strikes without prejudice for obtaining further patent protection. The An notifier reserves the right to add more, so far only in the description and / or To claim drawings disclosed combination of features.

Relationships used in subclaims point to further training the subject of the main claim by the features of the respective towards subclaim; they are not considered a waiver of achieving one independent, objective protection for the combination of features to understand related subclaims.

Since the subjects of the subclaims with regard to the prior art reserves the right to make its own independent inventions on the priority date  Applicant before becoming the subject of independent claims or part to make statements of compliance. You can also continue to invent independently containing one of the subjects of the preceding subclaims Chen independent design.

The exemplary embodiments are not to be understood as a limitation of the invention hen. Rather, there are numerous variations within the scope of the present disclosure Rations and modifications possible, especially such variants, elements and combinations and / or materials, for example by combination or modification of individual in connection with that in the general Be writing and embodiments and the claims described and in the features, elements or process contained in the drawings steps can be taken by the person skilled in the art with regard to the solution of the task are and through combinable features to a new item or lead to new process steps or process step sequences, also insofar as they Manufacturing, testing and working procedures concern.

Claims (27)

1. A method for controlling and / or regulating an automated clutch and / or an automated transmission of a vehicle, in particular a motor vehicle, in which a torque reduction is carried out during a coupling phase, characterized in that the torque reduction is carried out in such a way that the acceleration of the vehicle is broken down as evenly as possible in order to avoid vibrations of the drive train of the vehicle. 2. The method according to claim 1, characterized in that during the Disengaging phase the clutch torque according to a suitable function is broken down. 3. The method according to any one of claims 1 or 2, characterized in that that at least at the beginning of the disengagement phase due to the moments construction slip on the clutch is permitted. 4. The method according to any one of claims 2 or 3, characterized in that the clutch torque is reduced, the temporal profile of the clutch torque (T _c ) is initially given by a parabolic function and then by a linear function. 5. The method according to any one of claims 3 or 4, characterized in that at the beginning of the torque reduction slip on the clutch is admitted that the parabolic reduction of the clutch torque (T _c ) is carried out approximately in a time interval (τ _g ), and that a linear reduction in the clutch torque (T _c ) is seen before after a decay time (τ _R ). 6. The method according to any one of claims 3 to 5, characterized in that the time profile of the clutch torque (T _c) is determined by an on fang clutch torque (T _{c, 0)} and / or by the slope of the initial clutch torque _{(c, 0)} , 7. The method according to claim 6, characterized in that the initial clutch torque (T _{c, 0} ) is determined by the following equation:
T _{c, 0} = α. (T _{e, 0} - J _{e, 0. E, 0} ), where
T _{c, 0} = initial clutch torque,
α = ratio of transferable clutch torque and dynamic engine torque,
T _{e, 0} = initial engine torque,
J _e = moment of inertia of the motor,
_{e, 0} = angular acceleration of the motor at the start of the decoupling process. 8. The method according to claim 7, characterized in that the ratio (α) is approximately in the range from 1.0 to 1.025. 9. The method according to any one of claims 7 or 8, characterized in that the slope of the initial clutch torque ( _{c, 0} ) is determined by the following equation:
_{c, 0} = β. _{c, max} , where
_{c, 0} = slope of the initial clutch torque,
β = ratio of the start and end degradation rate of the transmitted clutch torque,
_{c, max} = maximum slope of the clutch torque. 10. The method according to claim 9, characterized in that the ratio (β) is in the range of 0.3 to 0.6. 11. The method according to any one of claims 1 to 10, characterized in that the time course of the clutch torque (T _c ) is described by the following equation:
T _c (t) = T _{c, 0} + (s ₀ + bt) .t for t ≦ τ _g and
T _c (t) = c + s. (T - τ _g ) for t <τ _g , where
T _c = nominal curve of the clutch torque,
s ₀ = initial slope of the clutch torque
s = slope of the linear torque reduction,
t = time at the beginning of the disengagement phase,
τ _s = duration of parabolic coupling torque reduction,
b and c = parameters. 12. The method according to claim 11, characterized in that the parameter (b) satisfies the following condition:
13. The method according to claim 11 or 12, characterized in that the parameter (c) satisfies the following condition:
c = T _{c, 0} + (s ₀ + .τ _g ) .τ _g 14. The method according to any one of claims 11 to 13, characterized in that the following approach applies to the slope at the beginning of the torque reduction (see above):
s ₀ = β. s, where
b = ratio of the initial slope of the torque reduction to the final slope. 15. The method according to any one of claims 11 to 14, characterized in that the following approach is chosen for the initial slope of the clutch torque (T _{c, 0} ):
T _{c, 0} = α. (T _{e, 0} - J _e . _{E, 0} ), where
α = ratio of dynamic engine torque to transferable clutch torque at the start of torque reduction,
T _{e, 0} = initial engine torque,
J _e = moment of inertia of the motor,
_{e, 0} = angular acceleration of the motor at the start of disengagement. 16. The method according to claim 14, characterized in that the ratio nis (β) is in the range from 0 to 1 and is varied in steps of 0.2. 17. The method according to claim 15, characterized in that the ratio (α) is in the range from 0.8 to 1.1 and is varied in steps of 0.05 and that the initial engine torque (T _{e, 0} ) is in the range of about 100 Nm. 18. The method according to any one of claims 1 to 17, characterized in that a simulation model is provided to optimize the torque reduction will see. 19. The method according to claim 18, characterized in that in the Si simulation model at least the rotating mass of the motor, the rotating mass of the transmission, the rotating mass of the vehicle, the elasticity of the on drive shaft, the damping of the drive shafts and the elasticity and / or the damping of the clutch can be used. 20. The method according to any one of claims 1 to 19, characterized in that the slipping torque reduction is achieved by a KME Global strategy factor is set to a value <1. 21. The method according to claim 20, characterized in that the following approach is chosen for Maubenaubau:
M _Kup = KME. (M _Mot - J _Mot . _Mot ), where
M _Kup = clutch torque,
KME = factor of global strategy,
M _Mot = engine torque
J _Mot = moment of inertia of the motor,
_Mot = angular acceleration of the motor. 22. The method according to any one of claims 20 or 21, characterized in net that the KME factor during the torque reduction to a value is decremented less than 1 until a predetermined minimum is reached. 23. The method according to any one of claims 1 to 22, characterized in that the gradient of the clutch torque in the linear range driving situation is determined depending on the tion as a shift comfort parameter. 24. The method according to any one of claims 1 to 23, characterized in that the initial gradient in parabolic torque reduction in the Zu in connection with a situation-independent KME factor becomes. 25. The method according to any one of claims 1 to 24, characterized in that the initial gradient for linear torque reduction with a ge suitable moment offset is combined. 26. The method according to any one of claims 1 to 25, characterized in that the initial gradient is specified such that it at least a constant portion of the gradient for linear Mo depending on the gear ment reduction is.   27. The method according to any one of claims 1 to 26, characterized in that essentially as the period of parabolic torque reduction a gear-dependent constant is selected.