DE10113103A1 - Road vehicle drive slip regulation involves setting second threshold with fixed, speed-dependent components, drive slip regulation motor control activated if second threshold exceeded - Google Patents

Abstract

The method involves forming a first component of a drive slip regulation motor regulation threshold as a gas pedal component representing the parameter dependent on the gas pedal position and setting a further motor initiation threshold containing a fixed component and a speed-dependent component, whereby drive slip regulation motor control is activated if the second threshold is exceeded.

Description

The invention relates to the control thresholds of a drive slip control for a road vehicle according to the waiter Concept of the invention according to claim 1 or according the preamble of the invention according to claim 2.

Today's vehicles are largely with an An tiblock system (ABS) and with a drive slip control (ASR). The ABS / ASR can be part of this a conventional brake system or part of an egg electronic braking system (EBS).

ABS / ASR systems have the task of braking or braking Blocking or spinning off the vehicle to prevent the wheels, and the respective Slip on the wheels (only the drive wheels on the ASR) to adjust an optimal setpoint. This can e.g. B. are around 10 percent. For this, the wheel speed len of the vehicle with speed sensors, this Values supplied to an electronic control unit and there with the help of appropriately programmed microprocesses processed. The system emits control signals that Solenoid valves are fed to those wheels that  tend to block or spin sen.

In ASR systems, ASR differential brakes are used regulation the drive wheel that spins, abge slows. As a result, the axle differential is a Transfer torque to the other wheel. However, should the Slip on one wheel get too big or both drive Spin the wheels, is in the course of the ASR engine control the engine control intervened and in addition the Mo Goal speed or performance against the driver's specification reduced. If there has been a response, so The interventions of the ASR differential often complement each other brake control and ASR engine control. A more precise one Description of such a known ABS / ASR system for example in the WABCO brochure "The integrated safety system for commercial vehicles, anti-lock braking system ABS with ASR traction control system ", March 1987, 5-5.3, included (this font is referred to below as E1 records.

Different slip apply to ASR control systems thresholds for the ASR differential brake control and the ASR engine control, so that there are also different Threshold designations for the ASR differential brakes control or the ASR engine control result.

There is slip for the ASR differential brake control

V _HR - V _HL if V _HR <V _HL [1a]

respectively

V _HL - V _HR if V _HL <V _HR [1b]

decisive, where V _{HR represents} the speed of the right drive rear wheel and V _{HL represents} the speed of the left drive rear wheel.

The differential brake control provides a limit value rain in which, if the target limit value is exceeded, namely the ASR differential brake threshold, the Differential brake control is activated and for as long is effective until the ASR differential brake threshold min is reached or fallen below again.

The ASR differential brake threshold represents a compromise between various influencing factors, some of which have contradicting effects, and is in accordance with the St. d. T. z. B. set as

2 km / h + 12% .V _vehicle , [2]

where V _{Fz represents} the vehicle speed.

The ASR differential brake threshold therefore has one fixed offset of 2 km / h and a high speed proportion dependent on density; through the speed dependent share is the ASR differential brake control suppressed if possible at higher speeds  become. This is useful to make both permanent Intervention with a corresponding load on the brake (Temperature and wear), as well as one-sided Braking possible yaw moment, which the vehicle over tries to turn its vertical axis at higher ones To avoid speeds.

The ASR differential brake control sets with friction coefficient differentiated between the left and the right An drive wheel (e.g. left asphalt, right ice) and acts against the sagging of the drive wheels on the Road section with a lower coefficient of friction.

For the ASR engine control there is slip

V _HM - V _Fz [3]

authoritative; V _{HM is} the average speed value of the driven rear axle wheels. The vehicle speed V _Fz is z. B. determined as speed mean value of the non-driven front wheels.

The ASR engine control threshold represents a compromise for e.g. B. different loading conditions, different friction values, relationship of traction to stability. The ASR engine control threshold corresponding to St. d. T. is z. B. set as:

3 km / h + 2% .V _FZ [4]

The threshold therefore basically consists of a fixed one Offset value, but includes a proportion proportional to Vehicle speed, e.g. B. Tire tolerances to be into account.

The invention relates primarily to the case of a very low coefficient of friction (ice, smooth snow, wet Blue basalt, etc.) and not the case of high friction differences between the drive wheels; in this case So it’s very likely that both wheels will go through turn and the ASR engine control takes effect. A ASR differential brake control occurs in this case if at all, in addition to the ASR engine control and temporally limited to. Both regulations can then be the same be active early. For this reason, in the case of very low friction on both sides is the case of ASR Engine brake control Starting point for further behavior of the control system.

When starting and accelerating on this very low Friction coefficient is the problem that the ASR engine re gel threshold in terms of optimal traction and Stability is too high. The driver can only supplement intervene by being very sensitive to the accelerator pedal withdraws completely and tries to get one Slip below the ASR engine control threshold s.

The invention is therefore based on the object  ASR engine control threshold to improve so that at very low friction values the traction is improved.

This object is achieved by the in claims 1 or 2 stated inventions solved; further developments and advantageous embodiments of the invention are specified in the subclaims.

The inventions have the advantage that with the Trakti an increase at the same time an increase in pages executives is achieved, which is an improvement in Stability brings about.

Another advantage of the inventions is that the improvement in stability is also effective when driving is sam.

A development of the invention has the advantage that Driver modifying the ASR engine control threshold via the accelerator pedal a starting process with his subjek can influence the driving sensation itself sensitively.

The invention is based on an embodiment, that is shown in the drawings, explained in more detail tert. Show it:

Fig. 1a, the ASR engine control threshold according to the addition of an accelerator pedal fixed size and an accelerator pedal variable size;

FIG. 1b shows different variants of the accelerator pedal Varia belgröße as a progressive, linear and de gressiver profile over the accelerator pedal threshold;

Fig. 2 shows the courses of the driving force factor µ _An and the cornering force factor µ _S for a high and a low coefficient of friction with the ASR engine control threshold suitable for both cases.

In the exemplary embodiment, a two-axle road vehicle equipped with ABS and ASR with a rear axle drive (4 × 2) is assumed, as shown in Fig. 5 of the E1.

The vehicle is equipped with a rear axle drive, so that the two rear axle wheels "left" and "right" represent two drive wheels, which about the difference tial transmission and the manual transmission with the output shaft of the drive motor are rotatably connected. The front the "left" and "right" represent two non-driven Wheels; all wheels are with a braking device provided which act by the driver's brake pedal be fourth. To determine the wheel speeds for the ABS and ASR functions are sensors on all wheels Determination of the wheel speeds arranged; for this purpose are the electrical outputs of the sensors with the electronic control unit connected. To carry out  The ABS and ASR functions are on the wheels of the driver Stuff to be operated by the electronic control unit Valve devices are provided, which are able the braking force on the wheels, regardless of the brake force specification of the driver via the brake pedal change [decrease or increase].

For the pure ASR function [the ABS function is not as such] it is necessary as such that these valve devices for the brakes of the drive wheels are provided, which are independent of each other be operated by the electronic control unit can.

The one transferred from the drive wheels to the road Drive torque is through the position of one by the driver actuated accelerator pedal, which is the drive engine controls. For the ASR function is one of the electronic control device to be operated device provided by the accelerator pedal position is able to reduce the specified drive torque.

It should be added that the invention also applies to vehicles with more than four wheels is applicable, such. B. at egg four-wheel drive vehicle provided, and in a vehicle with a lifting axle there are two other non-driven wheels.

The vehicle speed V _Fz required for the formulas [2] and [3] is calculated in the electronic control unit from the wheel speeds of the non-driven wheels. In four-wheel drive vehicles, for. B. using certain filter functions, the wheel speeds of the driven wheels are used to determine the vehicle speed V _Fz .

According to the formulas [1a] and [1b], the elec tronic control unit determines a differential slip, which is the wheel related to vehicle speed speed difference between the wheel speeds of the left and the right drive wheel. Under use an ASR differential brake threshold, the z. B. correspond chend formula [2] is formed, is exceeded this threshold due to the differential slip from the elec tronic control unit as a limit control formed ASR differential brake control performed, wel by braking intervention on at least one of the drives gears the differential slip to the specified ASR differences rential brake threshold reduced.

In the electronic control unit continues to correspond According to equation [3] an average value slip determines which cher the difference from that from the wheel speeds of the lin ken and the right drive wheel formed middle Wheel speed to the vehicle speed. In the electronic control device is under a given ASR engine control threshold as Limit control trained ASR engine control leads, which by reducing the drive from the driving torque transmitted to the road  Average slip to the specified ASR engine rule threshold reduced. The facility provided for this to reduce the engine torque in new sys temen executed so that the electronic Steuerein directly into the vehicle's engine control electronics intervenes. According to formula [4] is the ASR engine control threshold determined by adding two parts, where the first part is a fixed value [first term of Formula as a fixed offset value of a speed] and the second part is one of vehicle speed dependent size [second term of the formula]. It may be added that it is also possible to add the two An share further shares according to formula [4] watch, which then depends on other sizes are designed.

In FIG. 1a, values for the ASR motor control threshold are plotted on the ordinate, which are plotted as a function of the accelerator pedal position FP plotted on the abscissa in percent. The dash-dotted straight line ( 6 ) shows the explained fixed value portion corresponding to the first term of formula [4].

According to the first part for the at least two parts of the ASR engine control threshold, which at Prior art represents a fixed value as Fahrpe dal portion formed, d. H. this share represents one depends on the position of the accelerator pedal.  

Formula [4] is thus replaced by the context according to the invention

K (FP) + 2% .V _Fz [5]

This accelerator pedal component K (FP) is designated as Λ in FIG. 1a under reference number ( 2 ).

As also shown in Fig. 1a, the accelerator pedal part ( 2 ) itself is determined by the addition of at least two sizes, the first size being given by a _fixed pedal size Λ _fixed ( 1 ) and the second size corresponding to is given below described Fig. 1b by an accelerator pedal variable size (3), (4) or (5), which depends on the position of the accelerator pedal.

In addition to these two variables to form the accelerator pedal part ( 2 ), further variables can be provided that depend on their variables, so that the accelerator pedal component is determined by the addition of at least two variables.

When starting, the vehicle speed is initially zero, so that the ASR engine control threshold is initially formed only by the accelerator pedal component Λ, and accordingly the function of the accelerator pedal component ( 2 ) above the accelerator pedal position, the accelerator pedal component can be sensitively felt change between a low threshold of 1 km / h when the accelerator pedal is not actuated and a comparatively high threshold of 3 km / h when the accelerator pedal is fully actuated, the latter value corresponding to the fixed ASR engine control threshold ( 6 ) in accordance with the prior art. The driver now has the option of independently selecting the size of the ASR engine control threshold for starting by pressing the accelerator pedal accordingly between the aforementioned sizes.

According to the course of the adhesion curves, the Driver the opportunity to slip [3] the road Adjust the coefficient of friction accordingly.

With higher coefficients of friction, the accelerator pedal becomes corresponding this desired target slip operated more strongly [in Direction 100%] the ASR motor control regulates a ver equally large slip, an approved [yet non-regulated] larger slip creates a ver equally better propulsion. At such a higher one Road surface friction is the engagement of the ASR differential brake control is not likely, so a related comfort impairment is eliminated.

With very low coefficients of friction, on the other hand, a small one ASR engine control threshold with a very low vehicle dal default selected.

The ASR engine control regulates a small slip [cf. [3]] from. Due to the low slip the be leadership improved. In addition, the ASR differences tial brake control compared to St. d. T. less often  active. The alternating right / left braking of the Differential brake control can be considered by the driver be felt uncomfortable.

Because in the invention with small accelerator pedal Set very small ASR engine control thresholds are bar, it could lead to the undesirable response of the ASR engine control coming. Therefore, according to the invention in addition to the ASR engine control threshold, another ASR-Mo gate control threshold provided.

Because when you accelerate a vehicle it's always an on drive slip would exist without such an incentive ASR engine control even at higher levels Often become active and reduce slip, so that an acceleration of the driver desired Vehicle would not be guaranteed in every case. In the ASR indicator lamp would also light up in these cases, which bothers the driver.

For the ASR motor control threshold is the same Way as for the ASR engine control threshold according to equation [4] a fixed value component [preferably 5 km / h] and a Proportion chosen proportional to the driving speed. To this may include at least two parts even more shares come from other sizes are dependent.

ASR engine control only becomes active when the ASR Control threshold is exceeded, but then regulates,  once activated by the ASR engine control threshold determined according to formula [5]. The fact that the scheme only when the "normal" ASR control threshold intervenes, is at high undesirable ASR control avoided.

With the combination of an "insensitive ASR control threshold "and one with the corresponding accelerator pedal actuation are "sensitive" ASR engine control threshold difficult start-up manageable without normal Starting processes are somehow impaired.

In Fig. 1b, the accelerator pedal variable size Λ is shown _variable as a function of the accelerator pedal position; as he mentions above, three different configurations ( 3 ), ( 4 ) and ( 5 ) are shown.

It is a first pedal threshold provided for in Fig. 1b, a value (9) of 10 percent and a second accelerator pedal threshold for which in Fig. 1b a value relates to (11) 100 percent [Λ _variable (3 ) and ( 4 )] is selected. For all positions of the accelerator pedal less than or equal to the first accelerator pedal threshold, the accelerator pedal variable size ( 3 ), ( 4 ) and ( 5 ) is zero; for all positions of the accelerator pedal is equal to or greater than the second accelerator pedal threshold, it is equal to an accelerator pedal Final value, for whose value ( 13 ) in Fig. 1b 2 km / h is selected, and for all positions of the accelerator pedal equal to or greater than the first accelerator pedal threshold, but less than or equal to the second accelerator pedal threshold, the accelerator pedal variable size increases Λ _variable ( 3 ), ( 4 ) and ( 5 ) from zero and reaches the accelerator pedal end value at the second accelerator pedal threshold. As he thinks, the curves of Λ _variable ( 3 ) and ( 4 ) reach this final value at the second threshold ( 11 ) of 100 percent that applies to them. On the other hand, in order to show the procedure for a second accelerator pedal threshold of not equal to 100 percent, the second accelerator pedal threshold is set at 70 percent for curve Λ _variable ( 5 ), so that this curve enters the final accelerator pedal value when this value is reached takes.

In Fig. 1b further areas are shown, within which the parameters mentioned can be sensibly selected: According to the value range ( 10 ) for the first Fahrpedal threshold, this can be set between 0 percent and 90 percent, corresponding to the value range ( 12 ) for the second accelerator pedal threshold is adjustable from 10 percent to 100 percent, whereby the second accelerator pedal threshold is to be selected at least larger than the first accelerator pedal threshold, and according to the value range ( 14 ) for the final accelerator pedal value, this is from 1 km / h to 6 km / h adjustable.

For the course of the accelerator pedal variable sizes Λ _variable ( 3 ), ( 4 ) and ( 5 ), alternative function courses from the first to the second accelerator threshold are shown. The function Λ _variable ( 3 ) has a horizontal tangent at the first accelerator pedal threshold and is designed as a progressively increasing function, ie its slope increases with increasing approach to the second accelerator pedal threshold. The selection of such a function curve represents a preferred embodiment, since a sensitive adjustability is guaranteed for small coefficients of friction, and the sensitivity for larger coefficients of friction is no longer required to this extent.

The curve Λ _variable ( 4 ) shows a linear course between the first and the second accelerator pedal threshold; this function has a uniform adjustability. The function Λ _variable ( 5 ) shows that it is also possible to provide a degressive course of the function, in which the gradient decreases as the second threshold is approached.

It is added that in Fig. 1a a value ( 7 ) of 1 km / h is selected for the above-described accelerator pedal _fixed size Λ, and that a value range ( 8 ) of 0.5 km / h to 3 for this fixed size km / h can be sensibly preselected.

The effect of the change of the ASR engine control threshold according to the invention on the driving behavior of the vehicle is shown in FIG. 2: the drive force coefficient µ _An as a function of the center slip λ _{M of} the engine control corresponds to the representation of the drive force coefficient µ _An of Fig. 2 from the E1 depending on the drive slip λ. In comparison to Fig. 2 from E1, Fig. 2 shows only the fourth quadrant, ie the quadrant that relates to traction control.

In Fig. 2 courses of the drive adhesion coefficient µ _{An are shown} as solid curves once for the road condition of the dry asphalt ( 20 ) and once for the snow-covered road condition ( 21 ). In addition, for these two road conditions, the lateral guiding forces F _{S are drawn in} as dashed lines, in such a way that the lateral guiding forces are related to the vehicle weight G and which result in the cornering force coefficients

are directly comparable with the driving force coefficients µ _{An in} terms of value. For dry asphalt, curve ( 22 ) shows the cornering coefficient µ _S , and for snow-covered roads, curve ( 23 ) shows the course of the cornering coefficient µ _S

The effect of the ASR engine control threshold modified by the accelerator pedal is to be explained using the example of a vehicle which is traveling at low speed and in which the accelerator pedal is fully actuated in the first case and the accelerator pedal is actuated only very slightly in the second case. Driving state for the first case:

V _Fz = 10 km / h
FP = 100%

According to formula [5] with K (100%) = 3 km / h, the ASR engine control threshold λ _S1 related to the vehicle speed V _Fz for the first case corresponds to the course ( 2 ):

In terms of value, the ASR engine control threshold λ _S1 is equal to the engine control threshold which, according to the design according to the prior art [cf. Formula [4] and dash-dotted straight line ( 6 )] results.

Driving state for the second case by taking back the accelerator pedal:

V _Fz = 10 km / h
FP = 10%

According to formula [5] with K (16%) = 1 km / h, the ASR engine control threshold λ _S2 related to the vehicle speed V _Fz , corresponding to the course ( 2 ), results for the second case:

In Fig. 2, the thresholds λ _S1 ( 24 ) and λ _S2 ( 25 ) are drawn; by reducing the accelerator pedal to 10%, the threshold is reduced by a difference Δλ _S ( 26 ).

In the first case, the intersection ( 27 ) of the engine control threshold λ _S1 ( 24 ) with the drive adhesion coefficient µ _An (λ _M ) ( 20 ) is on the stable branch of the coefficient, namely on the branch at which the coefficient is related in size to the Center slip λ _M increases. A stable traction control system is thus determined for the case of dry asphalt with the threshold λ _S1 .

The situation is different when it comes to the condition of the snow-covered road; there is the intersection ( 28 ) of the motor control threshold λ _S1 ( 24 ) with the drive adhesion coefficient µ _An (λ _M ) ( 21 ) on the unstable branch of the coefficient. On this branch, the drive force connection decreases in size with increasing slip, so that the control system is not able to compensate for the insufficient drive force connection by increasing the slip.

At the reduced threshold λ _S2, the point of intersection (29) is the motor control threshold λ _S2 (25) with driving force _to schlußbeiwert μ (λ _M) verscho screws (21) to the stable branch.

With the shift in threshold, the lateral guidance coefficient of the snow-covered road condition also increases from a value of approx. 0.1 at the intersection ( 30 ) to approx. 0.25 at the intersection ( 31 ).

With the reduction of the engine control threshold via driving So pedal becomes one with low friction values enables stable ASR engine control, and on the other hand the cornering forces are increased.

The stable ASR engine control has a very advantageous effect while starting off on a very slippery road. Ver if you compare the invention with the prior art, so is, as already explained above, in this fixed threshold of 3 km / h too high for road conditions: The wheels are spinning; the driver can only use the accelerator pedal fully withdraw, and then remains to start no drive torque left. With the accelerator pedal gene engine control threshold of the invention, however, is a sta Accelerated starting possible even in such extreme cases.

The increase in cornering forces affects during the trip very advantageous if the vehicle z. B. on an uphill road with the accelerator pedal fully depressed in a long curve on icy road areas device. At the first tendency to break out of driving the driver takes the accelerator pedal back, the sides executives increase and the vehicle is back stabilized.  

In addition to the discussed solution of the interaction of the ASR engine control with the ASR differential brake control there is also the case that the wheels of the drive axle are rigidly coupled to each other via a lock, and so with no speed differences between the drive wheels can occur, with which an ASR differential brake regulation becomes superfluous.

Such a lock can e.g. B. as a driver-operated Lock designed. With such a solution the driver is in a critical situation such. B. at Start on a slippery road, insert the barrier.

With such sole operation, the ASR engine regulation can be based on ASR differential devices brake control can be dispensed with, which leads to cost savings leads. For this mode of operation, the Need that the brakes of the drive wheels unab dependent on each other through the electrical control unit are operated, as well as the determination and evaluation of Wheel speed differences as part of an ASR differential braking control.

It should be added that it is also possible, in addition to the ASR Motor control threshold also for the ASR differential ASR differential brake threshold applicable speaking the explained for the ASR engine control threshold Form principles as accelerator pedal dependent variable. at of such a configuration, the ASR differential brake interventions  from the driver to the given Frictional conditions of the road can be adjusted.

Claims (13)

1. traction control for a road vehicle with a drive motor, with at least two Antriebsrä the wheels, sensors being arranged on the wheels, which are connected to determine the wheel speeds with the electronic control unit, and wherein in the road vehicle a device to be actuated by the electronic control device to reduce the drive torque transmitted from the drive wheels to the roadway, which is predetermined by the position of the accelerator pedal operated by the driver and used to control the drive motor, with the following features:

• a) the vehicle speed of the road vehicle is determined by the wheel speeds of wheels;
• b) an average slip is determined with the mean wheel speed, based on the vehicle speed, from the wheel speeds of the left and right drive wheels;
• c) it is designed as a limit control ASR engine control to reduce the mean slip to a predetermined ASR engine control threshold by reducing the drive torque transmitted from the drive wheels to the road to drive torque;
• d) the ASR engine control threshold is determined by the addition of at least two components, with two components providing a first and a second component and the second component representing a variable dependent on the vehicle speed;

characterized by the following features:

• a) the first component for the ASR engine control threshold is designed as an accelerator pedal component, which represents a variable dependent on the position of the accelerator pedal.
• b) in addition to the ASR engine control threshold, an ASR engine control threshold is provided, when the ASR engine control is activated and which is determined by the addition of at least two parts, two parts providing a first and a second part and the the first portion is a fixed value and the second portion is a variable dependent on the vehicle speed.

2. traction control system for a road vehicle with a drive motor, with at least two drive wheels and with at least two non-driven wheels, in which at least the drive wheels are equipped with a brake, and at least the brakes of the drive wheels can be actuated independently of one another by an electrical control unit, wherein sensors are arranged on the wheels, which are connected to the electronic control unit for determining the wheel speeds, and wherein in the road vehicle a device to be actuated by the electronic control unit for reducing the drive torque transmitted from the drive wheels to the roadway is provided, which by the Position of the accelerator pedal operated by the driver and used to control the drive motor is specified, with the following features:

• a) the vehicle speed of the road vehicle is determined by the wheel speeds of the non-driven wheels;
• b) with the wheel speed difference between the wheel speeds of the left and right drive wheels related to the vehicle speed, a differential slip is determined;
• c) an average slip is determined using the average wheel speed, based on the vehicle speed, from the wheel speeds of the left and right drive wheels;
• d) an ASR differential brake control designed as a limit value control for reducing the differential slip to a predetermined ASR differential brake threshold is provided by brake intervention on at least one of the drive wheels;
• e) it is designed as a limit control ASR engine control to reduce the mean slip to a given ASR engine control threshold by reducing the drive torque transmitted from the drive wheels to the road to drive torque;
• f) the ASR differential brake threshold is determined by the addition of at least two parts, the first part being a fixed value and the second part being a variable dependent on the vehicle speed in the case of two parts;
• g) the ASR engine control threshold is determined by adding at least two components, the first component being a fixed value and the second component being a variable dependent on the vehicle speed in the case of two components;

characterized by the following features:

• a) the first component for the ASR engine control threshold is designed as an accelerator pedal component, which represents a variable dependent on the position of the accelerator pedal.
• b) in addition to the ASR engine control threshold, an ASR engine control threshold is provided, when the ASR engine control is activated and which is determined by the addition of at least two parts, two parts providing a first and a second part and the the first portion is a fixed value and the second portion is a variable dependent on the vehicle speed.

3. traction control according to claim 1 or 2, characterized by the following features:

• a) the accelerator pedal portion is determined by adding at least two quantities;
• b) the first of the at least two variables is determined by an accelerator pedal fixed variable, namely a fixed variable;
• c) the second of the at least two variables is determined by an accelerator pedal variable variable, namely by a variable dependent on the position of the accelerator pedal.

4. traction control according to claim 3, characterized ge indicates that for the positions of the accelerator pedal a first and a second accelerator pedal threshold are featured are seen, each for both accelerator pedal thresholds a value between the position of the accelerator pedal of 0% and the position of the accelerator pedal can be selected from 100% is. 5. traction control system according to claim 4, characterized by the following features:

• a) For all positions of the accelerator pedal less than or equal to the first accelerator pedal threshold, the accelerator pedal variable size is zero;
• b) for all positions of the accelerator pedal equal to or greater than the first accelerator pedal threshold, but smaller or equal to the second accelerator pedal threshold, the accelerator pedal variable size increases from zero and reaches an accelerator pedal end value at the second accelerator pedal threshold;
• c) for all positions of the accelerator pedal equal to or greater than the second accelerator pedal threshold, the accelerator pedal variable size is equal to the accelerator pedal end.

6. traction control according to claim 5, characterized ge indicates that for the course of the accelerator pedal Va Belt size above the accelerator pedal position between the first and second accelerator threshold one per gressive course is provided. 7. traction control according to claim 6, characterized ge indicates that the course of the accelerator pedal is variable size above the accelerator pedal position at the position of the first accelerator pedal threshold a horizontal tangent having. 8. traction control according to claim 5, characterized ge indicates that for the course of the accelerator pedal Va Belt size above the accelerator pedal position between the first and the second accelerator pedal threshold one in the substantial proportional course is provided. 9. traction control according to claim 5, characterized ge indicates that for the course of the accelerator pedal Va Belt size above the accelerator pedal position between the first and second accelerator threshold a degres sive course is provided. 10. Traction control according to at least one of the An sayings 4 to 9, characterized in that for the first accelerator pedal threshold a value of the accelerator pedal position between 0% and 90%.   11. Traction control according to at least one of the An sayings 4 to 9, characterized in that for the second accelerator pedal threshold a value of the accelerator pedal Position between 10% and 100%, at least however larger than the first accelerator pedal threshold is. 12. Traction control according to at least one of the An sayings 3 to 9, characterized in that for the Accelerator pedal size is a value of the slip between 0.5 km / h and 3 km / h is provided. 13. Traction control according to at least one of the An sayings 5 to 9, characterized in that for the Accelerator pedal end value a value of the slip between 1 km / h and 6 km / h is provided.