WO2003076834A1

WO2003076834A1 - Driving mode changeover

Info

Publication number: WO2003076834A1
Application number: PCT/EP2003/002481
Authority: WO
Inventors: Bernd Wolgast; Norbert Weiss; Dieter Manigel
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2002-03-12
Filing date: 2003-03-11
Publication date: 2003-09-18
Also published as: EP1485640A1; DE10210795A1; DE10210795B4

Abstract

The invention relates to a method for a changeover of the driving mode of a motor vehicle between two or more driving modes of said vehicle, whereby the driving modes are respectively implemented by characteristic maps (FV1, FV2) and a corresponding propulsion request (VOR1, VOR2) is derived from each characteristic map. According to said method, from the time of the changeover of the driving mode from a first driving mode to a second driving mode, the propulsion request passes from a first characteristic map to a second characteristic map. The transition can take place by means of an adaptation factor (f1, f2), which is formed by calculating the quotient of the deactivated propulsion request and the activated propulsion request.

Description

Driving behavior change

The invention relates to a method for switching the driving behavior of a motor vehicle according to the preamble of claim 1 and a corresponding device according to claim 18.

In today's vehicles, the driver's desire for the drive is recorded electronically by suitable devices on the accelerator pedal. The resulting accelerator pedal signal is further interpreted in the control electronics of the vehicle. For this purpose, characteristic maps stored in the control electronics are used, which convert the accelerator pedal signal, as well as, for example, speed or rotational speed, into a quantity that specifies the propulsion request in a practicable manner. Such a variable for the propulsion request can be, for example, engine torque, wheel torque or injection quantity. The relationship between the accelerator pedal signal and the desire to propel is referred to as driving behavior.

In modern motor vehicles, there are cases in which a change in driving behavior is desired or also required. This is the case, for example, when operating a vehicle with an automatic transmission and wheel torque-oriented driving behavior. There, when selecting the tip alley in vehicles with automatic transmissions with manual switching options by the driver, there may be excessive dead travel in the accelerator pedal. Furthermore, a switchover may be desired to represent an economical and a sporty driving behavior, or it may be necessary to adapt the driving behavior in the event of a major change in the drive train conditions by engaging a terrain reduction.

For all changes in driving behavior, the requirements apply in driving operation that a changeover with the accelerator pedal position remaining on the one hand must not result in a jerk / jump in the propulsion request noticeable to the driver and on the other hand that there is no noticeable change in the propulsion or the propulsion request over time.

Today's mechanisms for switching the driving behavior do not meet the above requirements, but the driver notices a change in the driving behavior of the Motor vehicle. In other words, the transition from one driving behavior to another is not smooth or bumpy.

The invention is therefore based on the object of developing a method and a device for switching the driving behavior of a motor vehicle, the switching taking place smoothly and smoothly.

This object is achieved by the features of the method according to claim 1 and the device according to claim 18. Preferred embodiments of the invention are the subject of the dependent claims.

In the method according to the invention for switching the driving behavior of a motor vehicle between two or more driving behavior of the motor vehicle, the driving behavior being implemented in each case by characteristic maps and a corresponding driving request being derived from each characteristic map, the driving request starting from the time (tO) of the switching of the driving behavior ( VOR1, VOR2) of an activated or to be deactivated driving behavior is transferred from a first map (FV1) to at least a second map (FV2).

The transition preferably takes place on the basis of a function to be determined, which is in particular continuous or piece-wise continuous.

Furthermore, the transition from the first driving behavior to the second driving behavior preferably takes place within a predetermined time interval after the time (tO) of the changeover, as a result of which the transition from the first to the second map, i.e. Driving behavior, is complete.

Furthermore, the transition can take place depending on the driving situation, so that, for example, the transition on a straight route takes place in a different way than in a curve.

When the driving behavior is switched over, the propulsion request of the activated driving behavior is preferably multiplied by an adaptation factor which is formed by the quotient from the deactivated propulsion request to the activated propulsion request. With this measure, the resulting propulsion request remains constant and a jerk or jump is avoided.

Afterwards the multiplication factor has to be brought back to the value one within a reasonable time, so that not only qualitatively but also quantitatively the new driving behavior is changed.

A preferred embodiment of the invention is explained below with reference to the drawings.

Fig. 1 shows a known basic configuration of a switch between two different driving behavior, and

2 shows a preferred embodiment of the configuration according to the invention for switching between two driving behaviors.

The restriction to two driving behaviors in the preferred embodiments is only for illustration and the method can therefore be easily expanded to more than two driving behaviors.

The basic configuration for a known driving behavior switch is shown in FIG. 1. Two different driving behaviors are realized in one vehicle. From two input signals, namely the accelerator pedal signal FPS and a further signal, for example engine speed DZ, a first propulsion request VOR1 becomes in a first map FV1, which describes a first driving behavior, and a second in a second map FV2, which describes a second driving behavior Propulsion request derived. Instead of the speed DZ, other input variables can be selected. The limitation to two input variables is also not mandatory, more than two input variables can be used, but one of the input variables must be the accelerator pedal signal FPS. The two propulsion requests VOR1 and VOR2 are directed to a switch S which can be controlled via a switchover signal US. Depending on this switchover signal US, one of the propulsion requirements that corresponds to the desired driving behavior is selected and is passed on to a suitable controller (not shown), for example the engine controller. Such a procedure does not meet the requirements mentioned in the introduction, namely that there should be no jerk / jump in the propulsion request perceptible to the driver and that the propulsion request does not change significantly over time.

In contrast, the method (or device) shown in FIG. 2 fulfills the above-mentioned requirements. Here, too, propulsion requirements VOR1 and VOR2 are determined from the two input variables accelerator pedal signal FPS and speed DZ using corresponding maps FV1 and FV2, which embody different driving behavior. The output values VOR1 and VOR2 of the two driving behavior maps FV1 and FV2 are multiplied by a factor f1 and f2, respectively. A calculation unit T calculates these two factors, which are equal to one in normal driving operation, and then multiplies them in corresponding multipliers M1 and M2. The two propulsion requests then go to a switch S which is controlled by a changeover signal. A resulting propulsion request VOR then arrives at the engine control, not shown. Furthermore, the switchover signal US is sent to the calculation unit in order to trigger it to calculate the adaptation factor in the activated driving behavior in the event of a switchover.

At the time t _{0 of} a switchover between the driving behavior, the factor which is multiplied into the activated path is set to the quotient "deactivated propulsion request to activated propulsion request". If, for example, a switch is made from the first driving behavior, shown by the map FV1, to the second driving behavior, shown by the map FV2, f2 is set to VOR1 / VOR2.

The resulting propulsion request VOR therefore results as

VOR = f2 ^■ VOR2 = VOR1 / NOR2 ^• VOR2.

The resulting propulsion request remains constant after the switchover and a jerk or jump in the propulsion behavior is avoided.

The multiplication factor (in the example: f2) must then be brought back to one in order to switch not only qualitatively but also quantitatively to the new driving behavior VOR2. This is accomplished using the accelerator pedal signal in the manner described below.

In addition to the calculation of the factor f1 or f2, the current accelerator pedal value r _{0 is} also stored at the time t _{0 of} a switchover. Furthermore, to simplify the calculation, it is assumed that the value for the accelerator pedal position is normalized to zero when the accelerator pedal is not actuated. Otherwise an appropriate standardization must be carried out. The following cases can occur:

Case a: The adjustment factor is greater than one

For factors greater than one, the factor is reduced for accelerator pedal values that are below r ₀ . The new factor is calculated according to equation 1.

new = (fait - 1) ^• r _a kt / r ₀ + 1 equation 1

where f _a ι _t = f _ne u is then set.

It is

f _newly new value for the factor ff _a ι _t old value for the factor fr _nude current value of the accelerator pedal position r ₀ value for the accelerator pedal position at the time of handling or conversion of the last calculation of the factor

The factor thus reaches the value 1 as soon as the driver releases the accelerator pedal for the first time after the changeover, the factors initially being greater than one.

Alternatively, the factor can be linearly reduced for each negative pedal gradient. Then r ₀ of equation 1 is to be replaced by the previous value of the accelerator pedal position r _ak t-ι. The reduction is only calculated if the inequality r _ak t <r _{0 is} fulfilled. The following equation then results, which is a generalization of equation 1: fneu = (fait - 1) ^■ r _akt / r _ak t-ι + 1 equation 1 a

With

r _a n Value of the accelerator pedal position in the previous calculation.

It should be noted that equation 1 a corresponds to equation 1 for the first iteration, since in this case the following applies: r _a k-ι = r ₀ .

Case b: The adjustment factor is less than one

For factors less than one, the factor is reduced for accelerator pedal values that are above r ₀ . The new factor is calculated according to equation 2.

fnew = (fall ~ 1) "(rmax cycle) / ( ^(" max - T ₀ ) + 1 equation 2

where f _a | _t = f _ne u is set.

It is

f _newly new value for the factor f, f f _a i _t old value for the factor, r _act current value of the accelerator pedal position, r ₀ value for the accelerator pedal position at the time of driving behavior change or the last

Calculation of the factor, r _a x value for accelerator pedal position when the accelerator pedal is depressed.

The factor thus reaches the value 1 as soon as the driver fully depresses the accelerator pedal after the switchover.

Alternatively, the factor can be increased linearly for each positive pedal gradient. Then r _{0 must} be set to r _act after each sampling step. The increase is only calculated if r _akt > r ₀ . In this case, the following applies to the calculation:

fnew ⁼ (fait - 1) * (r _m ax ^_ cycle) (fmax "r _a kt-l) ⁺ With

Tma value of accelerator pedal position for depressed accelerator pedal (maximum value)

Due to the explained method for varying the factors, they are only adjusted in the moments in which the driver expects a change in the propulsion (desired) by moving the accelerator pedal. This ensures that the direction of the change in the factor and thus the propulsion request corresponds to that of the accelerator pedal. The only prerequisite for the correct functioning of the switchover described above is that the driving behavior maps provide output values which increase monotonically with increasing accelerator pedal signal. This corresponds to the normal expectation and advice.

In order to ensure that the factors are reset to the value 1 after a certain time, especially when driving at constant speed, an additional ramp function must be implemented, which reduces or increases the factors whenever the conditions for the pedal value (r _act > r ₀ or r _act <r ₀ ) are not fulfilled. The time constant of the ramp must be set to a value that ensures that the driver does not feel the change in the active factor.

LIST OF REFERENCE NUMBERS

DZ speed

FPS accelerator pedal signal

FV1 map first driving behavior

FV2 map second driving behavior

VOR1 Propulsion request regarding first driving behavior

VOR2 Propulsion requirement regarding second driving behavior

S switch

US switching signal

BEFORE resulting propulsion request

T Calculation unit (transition) f 1 adaptation factor for the first tunneling request f2 adaptation factor for the second tunneling request

M1 multiplier

M2 multiplier

Claims

PATE NTANS P RÜ CHE

1. A method for switching the driving behavior of a motor vehicle between two or more driving behavior of the motor vehicle, the driving behavior being implemented in each case by characteristic maps (FV1, FV2), and a corresponding propulsion request (VOR1, VOR2) being derived from each characteristic map, characterized in that starting from the time (tO) of switching the driving behavior, the advance request (VOR1, VOR2) of an activated or deactivated driving behavior is transferred from a first map (FV1) to at least a second map (FV2).

2. The method according to claim 1, characterized in that the transition takes place on the basis of a function derived from the propulsion requirements of the first and second characteristic diagram.

3. The method according to claim 2, characterized in that the function is continuous or piecewise continuous.

4. The method according to any one of the preceding claims, characterized in that the transition from the first driving behavior to the second driving behavior takes place within a predetermined time interval after the time (tO) of switching.

5. The method according to any one of the preceding claims, characterized in that the transition takes place as a function of the driving situation.

6. The method according to any one of the preceding claims, characterized in that at the time (tO) of switching the driving behavior, the propulsion request (VOR1, VOR2) of the activated driving behavior is multiplied by an adaptation factor (fl, f2), which is determined by the quotient of the deactivated propulsion request (VOR2, VOR1) is formed for the activated tunneling request (VOR1, VOR2).

7. The method according to claim 6, characterized in that at the time of the switchover (t ₀ ) the current accelerator pedal value (r ₀ ) is stored.

8. The method according to claim 6 or 7, characterized in that the adaptation factor (fl, f2) before the changeover time (t ₀ ) is one.

9. The method according to any one of claims 6 to 8, characterized in that the adaptation factor (fl, f2) after the switchover time (t ₀ ) is brought to the value one in a predetermined manner.

10. The method according to claim 8, characterized in that the adjustment factor (f 1, f2) is brought to the value one by means of a time-dependent function.

11. The method according to claim 9, characterized in that for adaptation factors (f1, f2) greater than one, the adaptation factor is reduced for accelerator pedal values (r _act ) which are below the accelerator pedal value (r ₀ ) at the time (t ₀ ) of the changeover.

12. The method according to claim 11, characterized in that the calculation of the reduced adjustment factor for factors greater than one is carried out according to the following equation: fnew ⁼ 1 ⁺ (fait - 1) ^' clock / l ^" o <where f _{new is} the new value for the Adaptation factor, fait the old value for the adaptation factor, r _a kt the current value for the accelerator pedal position, r _{0 is} the value of the accelerator pedal position at the changeover time t ₀ , and the value of the accelerator pedal position is zero when the pedal is not actuated.

13. The method according to claim 11, characterized in that the adaptation factor (fl, f2) is linearly reduced with each negative accelerator pedal gradient, the calculation of the new adaptation factor according to the equation: fnew = 1 ⁺ (fait - 1) - l ^" act fact -1> occurs, where f _{new is} the new value for the adjustment factor, f _a ιt is the old value for the adaptation factor, r _ak t is the current value for the accelerator pedal position, and r _a t-ι is the value of the accelerator pedal position in the previous calculation, and the value of the accelerator pedal position is zero when the pedal is not actuated.

14. The method according to claim 9, characterized in that for adaptation factors (f1, f2) less than one, the adaptation factor is increased for accelerator pedal values (r _act ) which are above the accelerator pedal value (r ₀ ) at the time (t ₀ ) of the changeover.

15. The method according to claim 14, characterized in that the calculation of the reduced adaptation factor for factors less than one is carried out according to the following equation: fnew ⁼ "I ⁺ (fait - 1) '( ^r max" lact) / ( ^r max "Hj) , where f _{new is} the new value for the adaptation factor, f _a ι _t the old value for the adaptation factor, r _act the current value for the accelerator pedal position, r ₀ the value of the accelerator pedal position at the switchover time t ₀ ,

Cmax is the maximum value of the accelerator pedal position, and the value of the accelerator pedal position is zero when the pedal is not actuated.

16. The method according to claim 14, characterized in that the adaptation factor (f1, f2) is linearly reduced for each negative accelerator pedal gradient, the calculation of the new adaptation factor according to the equation: fnew ⁼ 1 + (fait - 1) ^* ( ^r max ^{- r} act) / (rma ~ l ^" act-l)>, where f _{new is} the new value for the adaptation factor, f _a ι _t the old value for the adaptation factor, r _{act is} the current value for the accelerator pedal position, r _act -ι the value of the accelerator pedal position in the previous calculation is, r _{max is} the maximum value of the accelerator pedal position, and the value of the accelerator pedal position is zero when the pedal is not actuated.

17. The method according to any one of claims 11 to 16, characterized in that a ramp function is implemented that the adjustment factor to the value one Reduces or increases if the condition r _act > r ₀ for reduction or the condition r _act <r ₀ for increase is not fulfilled.

18. Device for carrying out the method according to one of the preceding claims, wherein the device has two or more driving behavior units, from which it consists of an input variable accelerator signal (FPS), which is derived from an accelerator pedal, and at least one further input signal, for example the engine speed ( DZ), for each driving behavior unit derives a propulsion request (VOR1, VOR2), which are given to a changeover switch (S) which, depending on a changeover signal (US), forwards the propulsion request (VOR1, VOR2) of the selected driving behavior to an engine control unit characterized in that the device has a calculation block (T) which calculates a transition from a first driving behavior to a second driving behavior from the propulsion requirements (VOR1, VOR2) and the accelerator pedal value.

19. The method according to claim 18, characterized in that the calculation block calculates an adaptation factor (fl, f2) for multiplication with the selected propulsion request (VOR1, VOR2) in a multiplier (M1, M2).

20. The apparatus according to claim 19, characterized in that the calculation block (T) for each propulsion request (VOR1, VOR2) of a driving behavior calculates an adaptation factor (fl, f2) which is multiplied in a multiplier (M1, M2) by the propulsion request.

21. Device according to one of claims 18 to 20, characterized in that the driving behavior contained in the driving behavior units are implemented by characteristic maps (FV1, FV2).