EP0835190A1

EP0835190A1 - Process and device for setting a driving torque

Info

Publication number: EP0835190A1
Application number: EP97923762A
Authority: EP
Inventors: Rolf Maier-Landgrebe
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1996-04-29
Filing date: 1997-04-28
Publication date: 1998-04-15
Also published as: BR9702186A; JPH11511093A; US6182003B1; WO1997040998A1

Abstract

The invention relates to a process for setting a driving torque in a motor vehicle, in particular torque setting within the scope of traction control. At least two controllable actuators are provided to control the driving torque, said actuators having different dynamic behaviour in relation to the setting of a driving torque. The invention consists in that a portion of the driving torque to be set is determined and used to control the actuator with a lower level of dynamics. The change caused by said control of the actuator with a lower level of dynamics is evaluated. The difference between the driving torque to be set and the evaluated driving torque is subsequently used to control at least one actuator with a higher level of dynamics.

Description

Method and device for setting a drive torque

State of the art

The invention is based on a method or a device for setting a drive torque according to the preamble of claims 1 and 10.

From DE-OS 42 39 711 a system for setting an engine torque is known, in which a predetermined by the driver and by a traction control system

Engine torque request is realized by varying the air supply, the ignition timing and / or the injection quantity.

From DE-OS 40 30 881 (corresponds to US 5,445,442) a traction control system is known in which a division of the traction control into a gimbal and a differential speed controller is presented.

In DE-OS 42 29 560 (corresponds to US 5,443,307) a traction control system is presented in which one Improvement of the controller properties is achieved by a differential speed controller, so that there is an improvement in the differential locking effect due to the brake intervention.

In the DE application 19542294.5 or in the article ATZ Automobiltechnische Zeitschrift 96 (1994) "FDR- Fahrdynamikregelung von Bosch" a subordinate traction control system is described within the framework of a driving dynamics control, in which to set the drive torque between a cardan moment acting on all driven wheels and one A distinction is made between the differential torque acting on the drive wheels. To set the drive torque as part of the traction control system, the desired gimbal and differential torque is distributed to the available actuators for setting the drive torque. Interventions on the wheel brakes and / or interventions in the control of the vehicle engine are available for this purpose. As is well known, these effects differ in their dynamic behavior.

The object of the present invention is to optimally distribute a drive torque request to the available torque intervention options.

This object is solved by the features of claims 1 and 10.

Advantages of the invention As already mentioned, the invention is based on a method for setting a drive torque in a motor vehicle. The torque setting within the framework of a traction control system is particularly considered here. At least two controllable actuators are available for influencing the drive torque, the actuators having different dynamic behavior with regard to the setting of a drive torque.

The essence of the invention is that a portion of the drive torque to be set is first determined and this portion determined is used to control the actuator with the lower dynamics. Furthermore, the change in drive torque caused by this actuation of the actuator with less dynamics is estimated. The difference between the drive torque to be set and the estimated drive torque is then used to control at least one actuator with higher dynamics.

This procedure leads to an optimal distribution of the drive torque requirement, taking into account the different dynamics of the actuators, to the available torque intervention options. In particular, it is provided according to the invention that to control the slow-acting

Only a part of the total drive torque request, in particular the stationary part, can be used for moment intervention. The faster-acting interventions then become dependent on the remaining portion and the Moment selected that is currently not possible due to the slow-acting moment intervention option.

If the drive torque setting according to the invention is a drive torque reduction to be set in the context of a traction control system (ASR), the invention leads to a uniform ASR interface for various engine controls.

In a very advantageous embodiment of the invention it is provided that an integral part of the drive torque to be set is determined as part of the drive torque to be set. As a result, only the longer-lasting torque request due to the slow-acting

Intervention realized, while the short-term requirements are only realized through the faster-acting interventions.

If the motor vehicle has a gasoline engine, it can be provided according to the invention that the actuator with lower dynamics changes the air supply, in particular the throttle valve position, while the actuators with higher dynamics vary the ignition timing, the fuel quantity and / or the braking force on the driven wheels.

The estimation according to the invention of the change in the drive torque caused by the control of the actuator with the lower dynamics can be done by means of a motor model. If the control of the actuator with the lower dynamics takes place by means of an actuating signal, this is done this estimate by filtering the actuating signal by means of a time filter (PT ^ element) and / or a dead time element (T _t element).

It is particularly advantageous that the proportion for controlling the actuator with the lower dynamic is determined in such a way that only positive drive torques are set. This means that towing or braking of the vehicle engine is not permitted.

Furthermore, it is provided in an advantageous embodiment of the invention that the portion for controlling the actuator with the lower dynamics is determined such that when there are low longitudinal vehicle _speeds and / or when there are friction values of certain different sizes on the vehicle _sides (μ _split condition) Drive torque is limited to a minimum, positive value. In particular, this should be the case when starting under a μ _split condition (friction values of the drive wheels are different)

Engine torque, which is obtained by the variation of the air supply, be limited to a value that is significantly greater than zero. This results in faster traction after the drive slip has been reduced, for example by changing the coefficient of friction.

In a further advantageous embodiment of the invention it is provided that the actuator of higher dynamics changes the fuel quantity, this change taking place in particular by reducing the fuel metering to individual cylinders of the vehicle engine. The control of this actuator over a predetermined time predicted, whereupon the activation is then prevented when the predicted activation falls below a threshold value. This configuration has the background that a suppression of the fuel injection generally only with a greater delay on the

Driving torque works. For this reason, the control over this delay time is predicted and the fuel injection is only suppressed if the prediction still indicates a desired fuel reduction at the time when the fuel reduction only has a driving torque-reducing effect.

Furthermore, it can be provided that in the event of a change in the fuel quantity, in particular by reducing the fuel metering to individual cylinders of the

Vehicle engine, this change is reduced or prevented if the drive slip (high wheel), which has the higher coefficient of friction, falls below a threshold value. This is done for reasons of comfort, since the high wheel, which essentially ensures the propulsion of the vehicle due to the low drive slip, should not be braked abruptly. This would lead to a comfort-reducing jerk.

The invention further relates to a device for carrying out the method described above for setting a drive torque in a motor vehicle.

Further advantageous embodiments of the invention can be found in the subclaims.

drawing FIG. 1 shows the invention using an overview block diagram, while FIG. 2 shows a detailed block diagram. FIGS. 3, 4 and 5 show details on the basis of flow diagrams or block diagrams.

Embodiment

The invention will be described using the exemplary embodiment described below. For this purpose, the essence of the invention, which lies in the torque distribution on the actuators, is described embedded in an overall system.

This overall system serves to regulate the drive slip in motor vehicles. The target drive slip values for the two drive wheels can either come from an upstream control and a superimposed driving dynamics controller. In the overall system, target braking torques for the two drive wheels and the target engine torque are then calculated. The target braking torques can be converted into brake pressure control signals for brake hydraulics in a downstream control. A throttle valve control signal can be determined from the target engine torque, for example, by a downstream control.

As already mentioned, the division of the traction controller into cardan and differential speed controllers is known from DE-OS 40 30 881. In the present exemplary embodiment, the two controllers are largely independent of those available Actuators designed. The distribution of the two controller variables setpoint cardan torque M _Kar and setpoint differential torque ^M Dif takes place in the downstream actuator-specific module. This makes it easier to supplement the throttle valve intervention with additional (quick)

Engine intervention types such as Ignition angle adjustment or injection suppression).

In FIG. 1, a superimposed driving dynamics controller (FDR controller) is identified by reference number 10. This FDR controller determines setpoints in particular according to a higher-level control and λg ₀ / _r for traction on the left and right driven vehicle wheels. For the disclosure of such a superimposed FDR controller, reference is made to the ATZ article mentioned at the beginning.

In addition to the target values and λg ₀ / _r for the drive slip on the left and right driven vehicle wheels, the FDR controller determines the free-rolling (slip-free) wheel speeds v _Rac jf _re i / ι and ^v Radfrei / r ^unc * ^ ^e rotational speeds v _Rac j / _{r of} the driven wheels. To determine the free-rolling (slip-free) wheel speeds, reference should again be made to the ATZ article mentioned at the beginning or to DE application 42 30 295.

The traction controller 11 are the setpoints and λ _So / _r for the drive slip on the left and right driven vehicle wheels, the free-rolling (slip-free) wheel speeds v _Rac jf _re ± / χ and v _{Ra (j} f _{rej / r} and the rotational speeds v _{Ra (} j / ι, v _{Ra (y} / _{r of} the driven wheels fed. The traction controller 11 then generates signals M _Rac jg ₀ / ι and M-RadSo / r 'in a manner to be described which correspond to the desired braking torques on the right and left driven vehicle wheels. These target braking torques are supplied to blocks 121 and I2r, by means of which, if necessary by means of a subordinate control loop, these braking torques are set on the wheel brakes. In addition, the controller 11 determines a target value M _SoMot for the engine torque, which is fed to the subordinate engine control 13.

Details of the traction controller 11 will be described below.

Setpoint determination 110:

In the setpoint determination 110, the wheel rotation speeds v _Rac j / 2 ^{and <} ^ ^v wheel / r ^ ^es left and right drive wheels, the free wheel rotation speeds ^v Radfrei / l and λ _So / _r for the drive wheels

Cardan rotation speed v _Kar as the mean value of the wheel rotation speeds and v _Racj / _r and the differential rotational speed v _Dj _f calculated as the difference between the _wheel rotational speeds v _Rad / ι and v _Racj / _r :

Actual rotation speeds:

^v Kar = < ^v Rad / l ^{+ v} Rad / r> I ² ^v Dif = ^v Rad / l ^"v Rad / r

From the target rotational _speeds v _SoRacj / _] _ and v _SoRad / _{r of} the wheels, which depend on the target drive slip λ _So / ι and λ are formed _so / _r, the target values can be determined _SoKar v and ^v SoDif f ^ur ^ ^e gimbal and differential speed:

^v SoRad / l = ^v Radfrei / l * ^{(1 + λ} So / l) ^v SoRad / r = ^v Radfrei / r * (l + λ _So / _r )

^v SoKar = < ^v SoRad / l + ^v SoRad / r> / ² ^v SoDif = ^v SoRad / l ^{~ v} SoRad / r

Determination of the operating state 111:

Operating states are determined in block 111, whereupon predetermined measures are initiated in response to certain operating states. As described in the aforementioned DE application 19542294.5, such a measure can be used

Changes in the low-pass behavior of the controller affect when there are such operating conditions in which

Powertrain vibrations are or may be present. This is because torsional elasticities in the drive train of the vehicle can cause drive train vibrations. In order to avoid such drive train vibrations, the cardan rotation speed v _Kar and the differential rotation speed v ^ f are passed in block 111 through a low-pass filter, the time constant τ of this low-pass filter being variable depending on the current operating state. The gimbal speed ^v Kar / f or differential speed ^v _D if / f filtered in this way is supplied to the gimbal speed controller 112 or the differential speed controller 113. Furthermore, a limitation of the target motor torque can be provided in block 111. The point here is that when a desired increase in engine torque Mg ₀ jyi ₀ t, a higher engine torque than the engine torque Mpy specified by the driver should not be possible. The driver request Mpy thus serves to limit the target engine torque. If the target motor torque is in this saturation, the flag stop is set. The motor torque saturation Mpy is determined with the help of the estimated current motor torque, where the stop is set when

^M SoMot> c_motstat * Mpy

with 0 <c_motsat <1.

PID cardan speed controller 112:

The gimbal speed controller (block 112) determines the gimbal speed v _Kar (or low-pass filtered gimbal speed v _Kar / f) and

Cardan rotation speed vg _oKar the cardan torque M _Kar . The cardan speed controller is designed as a PID controller with a proportional, an integral and a differential component. These proportions can be designed as follows:

- p-part;

If the low-pass filtering described above does not take place in block 111, as mentioned, this filtering can be carried out in the gimbal controller 112 according to the equation

^v Kar / f (t + l) = v _{Kar / f} (t) + C _fil * [v _Kar (t) - v _{Kar / f} (t)] are made, where Cf- _{Q is} a filter constant dependent on the above condition. The P component of the gimbal speed controller then corresponds to a PT ₁ component.

The gain Kp is selected in particular as a function of the currently effective total transmission ratio iges or i _w irk (total transmission ratio between the motor and the wheels) in order to take into account the moment of inertia of the motor with respect to the wheels, which is dependent on the gear stage.

where Cl and C2 are constants.

The output of the P component is:

^k np = Kp * (v _Kar / _f - v _SoKar ).

- D component Because of the drive train vibrations, the differentiator is designed essentially as in the aforementioned DE-OS 42 29 560 (corresponds to US 5,443,307):

^k dif = li _, * i ^{mot +} 2jrad] * [v _Kar (t) - v _Kar (t-vT)] / (vT),

where vT corresponds approximately to the oscillation period of the drive train vibrations, iQes ^ ^e currently effective total transmission ratio and the quantities jmot and jrad represent the inertia of the engine and the wheels. The D component has a dead zone. Their size εr _j if depends on the overall translation ices: ^ε dif = ^ε dif / a ⁺ ^ es * ^ε dif / b-

where ε _d £ f / _a and Are constants. The dead zone for the exit results

^k nd = ^c d [min (0, k _d i _f -ε _d if) + max (0, k _d i _f + ε _d if)].

where c _{d is} a constant.

- I share

The integrator gain is normal

κι = κ _{I / a +} i _Q ² _es * κ _{I / a} ,

where Kj / _a and Kj / j- are constants.

The integrator gain K _{j is} corrected in three different cases (I, II and III):

I. High μ criterion:

A roadway with a high coefficient of friction is recognized if the following five different conditions are simultaneously met:

! ■ ^λ Rad / l <min ⁽ ε _λl , λ _So / ₁₊ εχ ₂ ⁾

² - ^λ Rad / r < ^min < ^ε λl < ^λ So / r ^{+ ε} λ2> - where ε _{λl and} εχ ₂

Are constants. 3. vp> ε _v f, where ε _v f is a predefinable threshold value. 4. lir is not set, which means that the overlay

FDR controller provides no intervention. 5. Stability: Both drive wheels must be in the stable slip curve branch for a certain time, that is to say the cardan speed v _Kar may only have a relatively low "roughness" in its course. The following stability criterion is therefore checked:

The drive wheels are stable if:

-

the reference gimbal speed v _re f can be determined from the speeds of the freely rolling drive wheels.

If each of the five conditions above is met over the period t _m ^ _n ^, then K _j becomes high

^K I = ^κ Ihigh

set .

II. Increase the integrator gain

Conditions 1 and 2 described above are dated

High μ criterion adopted. Another condition is

3. k _d if <α ₂ * ktm * + ß ₂ ,

in which

ktm * = (i ^ _es * jmot + 2jrad) * (v _{SoKar t} - v _{SoKar | t} _; ι) / T is

If during the period t _m i _n2 each of the above three conditions is met, then K _{j is} raised to Kj ':

K _l '= C _intfalcl * KL

III. Lower integrator gain if the three conditions

1. k _n i <C _n ü _ow (k _n ^ is the current integrator value) and

2. v _Kar <v _SoKar and

3. og case II no longer than t _m i _n 3,

are satisfied, then the integrator gain K _j becomes K _j by

^κ l '= ^κ l / ^c intfak2

lowered.

The new integrator value is

^k ni, t + l = ^k ni, t ^{+ κ} I * ^(v Kar, t ^{_ v} SoKar, t> -

The integrator value is corrected in the following cases:

I) If

^k rom ^<ε krom is satisfied, k _n i becomes k _n i '

^k ni ' ,

This describes a dead zone, where

x = k _d - ^ f - ktm *.

II) The integrator value is limited below:

^k ni ^{= maχ /} - ^k ni ' ^k ni, min ^ ^■

III) The integrator is limited by the reduced driver torque M _{yes r} :

If k _n i> Mf _{ar is} fulfilled, two cases are distinguished:

If additional

^v Kar> ^v SoKar

applies, will

k _n ^ = Mf _ar " ^K I * ^k _ ^rorn

otherwise the old integrator value applies

^k ni, t ^{_ k} ni, tl

The output of the cardan controller consists on the one hand of the sum of the three controller components: ^M Kar = ^k np + ^k nd ^{+ k} ni

and secondly from the integrator value

^M KarI ^: = ^k ni

PI differential speed controller (block 113):

The PI differential speed controller (block 113) determines the differential torque Mp ^ f. The most important properties of the differential speed controller are described below:

- Setpoint expansion If the driving dynamics control flag lir is set, that is, that the superimposed FDR controller provides for an FDR intervention, the amount of the setpoint vg _0j 3if for the differential speed is increased to vg _oDj _f ':

^v SoDif '= <l ^v SoDifl + ^ε Difl * ^c) * ^si 9 ⁿ < ^v SoDif> -

otherwise the setpoint remains unchanged:

^v SoDif '= ^v SoDif-

- P component

If the low-pass filtering described above does not take place in block 111, as mentioned, this filtering can be carried out in differential speed controller 113 according to the equation

^v Dif / f ^{(t + 1)} = ^v Dif / f ^(fc) + Bfil * tv _Dif (t) - v _Dif / _f (t)] are made, where Bf- _j ^ is a filter constant dependent on the above condition. The P component then corresponds to a PT _] _ component.

The filtered control deviation is then ΔDif

Δ _Dif (t) = v _Dif / _f (t) - v _SoDif (t).

The output of the P component is

^d np = K _dp * Δ _Dif (t).

- I share

If Iir is set, which means that the superimposed FDR controller provides for an FDR intervention, the controller parameters provided with index 1 are used (i = 1), otherwise i = 2 applies.

When calculating the integrator value d _n ±, a total of four cases are distinguished depending on the control deviation Δr _j if and d _n ^. If the condition

^Δ _D if * d _n i <ε _άnl

is fulfilled in the case

l ^Δ Difl ^{> ε} '-2

the controller parameter c _d j_ _j _ (i) uses:

D ^d ni, t + l = ^d ni, t " ^c dil ⁽ i> * sign ⁽ d _{ni / t} ⁾ , otherwise c _d i ₂ (i) is used:

2) d _{ni / t + 1} = d _{ni / t} - c _di2 (i) * sign (d _{ni / t} )

If

^Δ Dif * ^d ni ^ ^ε dnl

and

lΔ _Dif l> ε _Difl

are fulfilled

3) d _{ni / t + 1} = d _{ni # t} + c _di3 (i) * d _rom ,

otherwise applies

⁴ > ^d ni, t _{+ l} = ^d ni, t "o _di4 (i) * sign ⁽ d _{ni / t} ⁾ .

The integrator dynamics are improved by tracking the integrator value in special cases with the P component:

d _ni = max (| d _n i I, c _d i ₄ (i) * Δ _Dif * sign (Δ _Dif ).

The integrator value is finally through

d _ni = min (| d _ni |, d _nimax ) * sign (d _ni )

limited up and down, - controller output

The controller output of differential speed controller 113 consists of the sum of the P and I components:

M _Dif = d _np + d _ni .

Torque distribution on actuators 114:

The distribution of the moments M _Kar (including the

Integrator _values M _Karj = k _n ^) and M ^ f on the actuators take place in block 114. The differential torque Mßif calculated by the differential speed controller 113 can only be applied by corresponding braking torque differences between the left and right drive wheels. In contrast, the gimbal torque ^M Kar calculated by the gimbal speed controller 112, ^which acts on ^the entire drive train, can be applied both by a symmetrical brake intervention and by an engine intervention.

The torque distribution 114 to the actuators in detail can be seen in FIG. 2. The gimbal torque MJ ^ _J - calculated by the gimbal speed controller 112 and the associated integrator _value M _j £ _arj as well as the differential _torque M _D if calculated by the differential _{speed controller} 113 are fed to the block 114 shown in dashed outline. On the output side, in addition to the target braking torques ^M RadSo / l ^{and M} RadSo / r, ^the control _signals M _SomotDk , M _SoZWV and M _Sot i for the engine _actuators throttle valve Dk 131, ignition angle adjustment ZWV 132 and injection suppression ti 133 are present. To determine the output signals, the effective gear ratio u _w - ^ _r ι _< (block 1143, gear ratio under certain circumstances taking into account the converter and / or clutch slip) is also determined in block 114, the longitudinal vehicle speed V _F (block 1144) and the knowledge of whether a so-called μ _sp τ_ _j _ _t condition is present (block 1145, drive wheels have significantly different coefficients of friction). The information on the effective transmission speed ratio u _w i _r iζ may originate from a transmission control unit, while the information about the vehicle longitudinal speed V _F and the presence of a so-called μ _S piit condition generally in the superimposed FDR regulator 10/1 available.

The individual steps which are carried out in the unit 114 can be seen in the sequence shown in FIG. These steps are described in more detail below.

After the start step 301, the above-mentioned variables are read in in step 302.

- Step 303: Determination of the target torque for the throttle valve intervention

The determination of the target torque for the throttle valve intervention is to be illustrated using the sequence shown in FIG. 4.

The one that acts relatively slowly on the drive torque

Throttle valve intervention should set the stationary end value for the drive torque to be set, therefore the reduced throttle valve setpoint torque M _red D _{] ζ} (the target drive torque to be set via the air supply) is initially equal to the integrator value M _] r _{ar j} . Due to the restriction of the reduced throttle valve set torque M _j - _g ^ _j ^ downwards (towards small moments), a drag operation becomes or braking operation of the vehicle engine is excluded:

^M redDk ^{: =} ^ ax [M _KarI , 0]

After the start step 401 and the reading in of the required data in step 402, the reduced throttle setpoint torque M _J _-QQ ^ _] ^ is thus determined in the above manner in FIG. 4 in step 403.

When starting a vehicle (longitudinal vehicle speed Vp below a threshold SW1, query result Y in step 404) of a vehicle, the drive wheels may have very different coefficients of friction (e.g. if the right drive wheel is on loose gravel or ice and the left drive wheel is on a dry road surface) ). If such a so-called μsplit condition exists (query result Y in step 405), the reduced desired throttle valve torque M _j - _g ^ _j ^ must not fall below a predeterminable minimum value Kl (step

406), so that the driving torque can be increased again quickly after the low wheel has been caught (wheel with the lower coefficient of friction). In this case, the engine torque reduction is not applied or only to a small extent by the throttle valve intervention, which acts more slowly on the drive torque.

Since the reduced throttle valve setpoint torque M _j -g ^ _j relates to the wheels, MgomotDk (control signal for

Motor control 13) the effective gear ratio are taken into account: ^M SomotDk ^{: = M} redDk / ^u effective

- Step 304: estimate the reduced throttle valve torque Mrgapkp

In order to estimate the drive torque currently realized by the throttle valve intervention, a correspondingly existing signal from the engine control 13 can be used directly, for which purpose a signal (not shown in FIG. 2) from the engine control 13 is fed to the block 114. If such a signal is not available, the estimation method shown in FIG. 5 is used.

For this purpose, the throttle valve torque MgomotDk determined in step 303 or 407 is supplied to an engine model 50. The behavior of the motor can be simulated in a simple manner by means of a PT 50 element 501 known per se and a dead time element T _t 502 known per se. The time constant τ of the P ^ element 501 is selected depending on whether the engine torque is increasing or decreasing, the dead time is dependent on the current engine speed. By multiplying (block 51) the estimated value related to the wheels by the effective gear ratio an estimate ^M motest is obtained ^{for the} drive torque caused by the throttle valve intervention.

Since, for example, time losses (calculation _times and data transmission) can lead to phase shifts, the estimated value M _redDKF for the reduced throttle valve _torque (based on the Drive wheels) determined as the mean of M _motest - and M _redDK (block 52):

^M redDkF ^: = < ^M motest + ^M redDk> / ²

Filtering is also an alternative

^M redDkF ^: = y * ^M motest + d-ϊ ⁾ * ^M redDk <

where the value γ is between zero and 1 [0 <γ <1].

- Step 305: Determination of the target torques for the

Ignition angle adjustment and injection suppression by the ignition angle adjustment ZWV and the injection suppression ti, the proportion K2 (eg 90%) of the difference between the estimated throttle valve torque ^M redDkF ^{and the} Sol1 cardan torque be applied. This results in the engine torque M _Z wv / ti ^{to be} applied by adjusting the ignition angle and suppressing the injection

^M ZWV / ti ^: = K2 * (M _redDkF -M _Kar ) / u _effective

- Step 306: Determination of the ignition angle adjustment Since the ignition angle adjustment ZWV acts faster than the injection suppression, the ignition angle adjustment has a higher priority than the injection suppression. The injection suppression is intended to apply the portion of the Mgwv / ti determined in step 305 that exceeds the portion of the torque caused by the actual ignition angle adjustment. The target value Mg ₀ zwv ^ ^for the

Ignition angle adjustment is therefore, taking into account the restriction to be described, equal to Mgwv / ti- The restriction mentioned is that the ignition angle adjustment to be set may only last for a certain period of time, since otherwise the engine control unit will display an error message due to the monitoring algorithms installed there.

In the ignition angle, the combustion torque compensates the drag torque unfired Mg _c hiepp of the motor and also produces the drive torque ^M motmodell ^{'the Pieter} h ^the engine model described above can be obtained:

^M motverbrenn ^{: _ M} motmodell * ^M Schle '

where the subtraction applies if the sign of Mg ^ iepp is negative.

- Step 307: Estimation of the moment caused by the ignition angle adjustment

Due to engine control restrictions, the

Setting the setpoint M _SoZ wv necessary

The ignition angle adjustment cannot always be adjusted.

Therefore, the target value Mg ₀ 2wv is not taken into account when calculating the other actuating torques, but rather a

Estimated value M _Z WVQ is formed for the engine torque actually caused by the ignition angle adjustment.

This estimated value M _Z wv _Q ^{k may} correspond to the torque acknowledged by the engine control, for which purpose a signal (not shown in FIG. 2) is fed from block 13 to engine 114. However, this is too take into account that such an acknowledgment signal generally has a relatively long dead time. For this reason, the torque actually caused by the ignition angle adjustment is advantageously estimated.

For this estimation it is assumed that the ignition angle is always adjusted to the maximum possible value ⁽ M _rnotver b _ren n * ^p max / l0θ ', which is just possible with the above-mentioned combustion torque Mmotverbrenn) to set the target value M _SoZW y. The estimate thus results in

^M ZWVQ ^: = ^min t ^M SoZWV, < ^M motverbrenn * ^p max / lOO ^ ^■

Alternatively, the estimate can also be as follows:

^M ZWVQ ^: = ^min t ^M SoZWV, ^M ZWVmaχ] '

where the value M _Z wv _{max is} a selectable parameter.

The drive torque caused by the ignition angle adjustment is then:

^M redZWVQ ^{: = u} effective * ^M ZWVQ

- Step 308: Determination of the injection suppression As already mentioned, because of the faster effectiveness, the ignition angle adjustment ZWV has a higher priority than the injection suppression ti. The injection suppression is intended to apply the portion of the M _Z wv / ti determined in step 305, that of the torque portion M _Z WVQ caused by the actual ignition angle adjustment goes out. The target torque Mg _ot i, which is to be achieved by suppressing the injection, should therefore first be determined by the difference between the torque M _Z wv / ti to be generated by the ignition angle adjustment and the injection suppression and the estimated value M _ZWV Q for the torque actually brought about by the ignition angle adjustment:

^M Soti ^{: = M} ZWV / ti ^"M ZWVQ

However, because the injection suppression only acts on the drive torque with a relatively large delay, the profile of the target torque Mg _ot i is predicted (predicted) over a certain period of time (for example 120 ms), which roughly corresponds to the delay. This can be done by methods known per se, in which, for example, from time derivatives (differentiate) the setpoint torque ^M ^Soti closes the future course. A predicted target torque Mg _ot ip _r for injection suppression is thus obtained.

If a comparison of the predicted target torque M≤otipr ^with the target torque Mg ₀ ti to be set determines that the target torque decreases sharply within the prediction time, the injection suppression is restricted or prevented.

Another restriction when determining the target torque for the injection suppression takes into account starting processes ⁽ vehicle longitudinal speed V _F below a threshold

SWl), in which the drive wheels are on parts of the road with different coefficients of friction. Is the Drive slip λ of the wheel with the higher coefficient of friction (high wheel) less than a predefinable slip threshold λ _s , then this high wheel can get into a brake slip due to the injection suppression. This means that the high wheel, which mainly ensures the vehicle acceleration when starting, by a

Injection blanking can be braked abruptly, which can lead to a comfort-reducing jerk. For this reason, when the conditions

V _F <SWl and λ <λ _c

are present, the target torque Mg ₀ ti for the injection suppression or the number of cylinders to be suppressed itself is reduced or set to zero.

Another restriction when determining the target torque for the injection suppression takes into account that the engine at a low speed by a massive

Injection quantity reduction is stopped (stalled). For example, it can be provided that at a

Engine speed below 900 rpm one

Injection quantity reduction is completely omitted, while only half as much due to an injection suppression to individual cylinders at an engine speed below 1200 rpm

Engine may be switched off.

Further restrictions can be taken into account when determining the target torque for injection suppression. The target torque M _sot i, which by a Injection suppression is to be achieved, then results as a function F of the above-mentioned variables:

^M S _θ ti ^{: = F} C (M _zwv / _ti -M _ZWVQ ); M _Sotipr ; ]

- Step 309: estimate of injection injection suppression. caused moment Because the injection blanking takes place per cylinder, that is, it only assumes discrete values 1 to 6 (with a 6-cylinder engine), the above-mentioned target torque ^M soti 'which is to be achieved by an injection blanking cannot normally be set precisely. When determining an estimated value M _t - _j _ _Q for the moment caused by the injection blanking, the moment obtained by means of the injection blanking must therefore

Discretization errors are taken into account. This is done by reversing the calculation equation for the number of cylinders to be hidden.

The drive torque caused by the injection suppression is then:

^M redtiQ ^: = u _active * M _tiQ

The sum of all drive torques that are caused by rapid engine interventions then results

^M redZWV / tiF ^: = ^M redZWVQ + ^M redtiQ

- Step 310: Determination of the symmetrical target braking torque The engine interventions (throttle valve, ignition and injection intervention) are supported by the relatively fast acting symmetrical brake intervention, by the brake intervention the difference between the estimated current engine torque and the entire drive torque M _j ^ _ar to be set:

^M Brsym ^: = tM _redDkF - ^M redZWV / tiF " ^M KarJ / ²

The division by 2 occurs because the symmetrical braking torque acts on both drive wheels.

The symmetrical braking torque Mg _j - _gy - _r can be filtered for convenience with a time filter with a predefinable time constant.

A further comfort-increasing restriction of the symmetrical braking torque M _j ^ _j - _g y _rr provides that the symmetrical braking torque Mg _j - _g y _jη does not become, or only insignificantly, greater than half of the drive torque applied by the motor.

Braking torque distribution (block 1142 / Figure 2): The braking torques of the two drive wheels consist of a superposition of the symmetrical braking torque Mg ^, _™ and

Differential moment Mr _j if. The sign of Mp ^ f decides on which wheel the greater braking torque is applied, i.e. which wheel is the so-called μ-low wheel. List of abbreviations:

FDR driving dynamics controller

Kl amplification of the I controller component.

Kp gain of the P controller component. Stop flag if target motor torque is in saturation. lir flag if FDR intervention is planned. ⁱ Ges total gear ratio motor-wheel. ^M Kar setpoint for the gimbal moment.

^M Dif setpoint for the differential torque.

^M SoMot setpoint for increasing the engine torque. M _FV engine torque specified by the driver.

^M RadSo / l Desired braking torque on the left driven

Vehicle wheel.

^M RadSo / r Target braking torque on the right driven

Vehicle wheel.

^M SoMot setpoint for the engine torque. S1, S2, S3,

SWl threshold values. ^v Wheel-free / l free-rolling (slip-free) rotation speed of the left driven vehicle wheel. ^v Wheel-free / r free-rolling (slip-free) rotation speed of the right driven vehicle wheel. ^v wheel / l rotational speeds of the left driven

Vehicle wheel. ^v wheel / r rotational speeds of the right driven

Vehicle wheel. ^v SoRad / l Setpoint for the rotational speeds of the left driven vehicle wheel. ^v SoRad / r Setpoint for the rotational speeds of the right driven vehicle wheel. ^v Kar cardan rotation speed. ^v Dif differential rotational speed. ^v SoKar setpoint for the cardan rotation speed. ^v SoDif setpoint for the differential rotational speed. ^v Kar / f filtered gimbal speed. ^v Dif / f filtered differential rotation speed. V _F longitudinal vehicle speed. ^λ wheel / l drive slip on the left driven

Vehicle wheel. ^λ wheel / r drive slip on the right driven

Vehicle wheel. ^λ So / l setpoint for the drive slip on the left driven vehicle wheel. ^λ So / r setpoint for the drive slip on the right driven vehicle wheel. τ, τ ₁ , τ ₂ time constants of the low-pass filter.

^M SomotDk control signal for throttle valve intervention. M _Sot i control signal for injection suppression. ^M KarI integrator value or stationary

Cardan torque. ^M SoZWV control signal for the ignition angle adjustment. ^M redDK reduced Drosselklappenm _^ ment ^M redDkF estimate for the reduced

Throttle moment ^and more effective gear ratio

Kl specifiable minimum value for the reduced throttle valve setpoint torque M _red £ _{) k}

Mm, otest Estimated value for the engine torque caused by the throttle valve intervention.

K2 constant. ^M ZWV / ti that through ignition angle adjustment and

Injection blanking to be applied

Drive torque.

^M SθZWV setpoint for the ignition angle adjustment. ^M ZWVQ Estimated value for the engine torque caused by the ignition angle adjustment.

^M Sθti target torque for the injection suppression ^M Sotipr predicted target torque for the

Injection blanking. λ _s slip threshold λ drive slip

^M tiQ estimate for that by the

Injection suppression caused engine torque. ^M redZWVQ estimates for that by the

Ignition angle adjustment caused drive torque. ^M redtiQ estimate for that by the

Injection suppression caused engine torque. ^M redZWV / tiF Sum of all drive torques caused by fast engine interventions.

M Brsym symmetrical braking torque

Claims

Expectations

1. A method for setting a drive torque (Mκ _ar ) in a motor vehicle, in particular in the context of a traction control system, with at least two controllable actuators (131, 132, 133, 12r, 121) for influencing the drive torque (Mj) _ar ), the actuators relating the setting of a drive torque have different dynamic behavior, characterized in that

a portion (M _jζarj ) of the drive torque (M _jζar ) to be set is determined, -the determined portion (M _j ς _arj ) for actuation (Mg _omo tτ3 _k ) of the actuator (131) with the lower dynamics, - which is used by this actuation (Mg _Qj notDjς) of the actuator (131) with a less dynamic change ( ^M redDkF 'of ^the drive torque is estimated and

the difference (M _red £ _{) k} pM _kar ) between the drive torque to be set (M _j ς _ar ) and the estimated drive torque (M _red £, _k p) for actuation (Mg _oZW v, ^M Soti 'of at least one actuator (132, 133, 12r, 121) is used with a higher dynamic.

2. The method according to claim 1, characterized in that an integral part (M _Karj ) of the drive torque to be set (M _jζar ) is determined as a proportion of the drive torque to be set (Mjζ _ar ).

3. The method according to claim 1 or 2, characterized in that the motor vehicle has a gasoline engine and the actuator (131) lower dynamics the air supply, in particular the throttle valve position, and the actuator (132, 133, 12r, 121) higher dynamics the ignition timing ( ZWV) and / or the amount of fuel (ti) and / or the braking force ( ^M RadSo / l ' ^M RadSo / r) ^on the driven wheels changes.

4. The method according to claim 1, characterized in that the estimation of the by the control (Mg _omot Dk) of

Actuator (131) with the less dynamic change (M _red £> _k p) of the drive torque is carried out by means of a motor model, in particular the control of the actuator (131) with the lower dynamics takes place by means of an actuating signal (Mg _omot D _k ) and for Estimation of the change (M _redDk p) of the drive torque caused by the actuation of the actuator (131) with the lower dynamics, the control signal (Mg _ornotDk ) using a time filter (PTx element) and / or a dead time element (T _t element).

5. The method according to claim 1, characterized in that the portion (M _KarI ) for actuation (Mg _omotDk ) of the actuator (131) with the lower dynamics is determined such that only positive drive torques (no drag torque) are set.

6. The method according to claim 1 or 5, characterized in that the proportion (I% _ar τ_) for actuation (Mg ^ u- _j ^ r ^) of the actuator (131) is determined with the lower dynamics such that when there is less Longitudinal vehicle speeds (Vp) and / or if there are friction values of certain different sizes on the vehicle sides (μ _split condition) the drive torque is limited to a minimum, positive value (Kl).

7. The method according to claim 3, characterized in that the actuator (133) of higher dynamics changes the fuel quantity (ti), this change taking place in particular by reducing the fuel metering to individual cylinders of the vehicle engine, and the control (Mgoti ^ this actuator via a predeterminable time is predicted and the activation (Mgoti ^ is prevented if the predicted activation falls below a threshold value.

8. The method according to claim 3, characterized in that the actuator (133) higher dynamics the amount of fuel

(ti) changes, this change taking place in particular by reducing the fuel metering to individual cylinders of the vehicle engine, and the control (Mg _ot j_) of this actuator (133) is reduced or prevented if the drive slip (high wheel) slips, which has the higher coefficient of friction, falls below a threshold value.

9. The device for performing the method for setting a drive torque (M _Kar ) in a motor vehicle according to claim 1 with at least two controllable actuators (131, 132, 133, 12r, 121) for influencing the drive torque (M _Kar ), the Actuators have different dynamic behavior with regard to the setting of a drive torque, characterized in that means (1141) for determining a proportion (Mκ _ar j) of the drive torque to be set (M _jζar ), the determined proportion (M _KarI ) for actuation (Mg _orno tD _k ) of the actuator (131) with the lower dynamics is used, means (1141) for estimating the change (M _redDk p) of the drive torque caused by this actuation ( ^M SomotDk 'of the actuator (131) with less dynamics, and Means (1141) for determining the difference (M _redjjk pM _Kar ) between the drive torque to be set (M _j £ _ar ) and the estimated drive torque (M _redDk p) and for actuation (Mg _oZ wv, Mg _ot ^) of at least one actuator ( 132, 133, 12r, 121) with a higher dynamic range depending on the determined difference.