U.S. patent application number 09/913471 was filed with the patent office on 2002-10-31 for method and device for adjusting the braking and/or drive effects on wheel of motor vehicles.
Invention is credited to Gawlik, Rolf, Mattern, Klaus-Peter, Schmitt, Johannes.
Application Number | 20020161504 09/913471 |
Document ID | / |
Family ID | 7932659 |
Filed Date | 2002-10-31 |
United States Patent
Application |
20020161504 |
Kind Code |
A1 |
Schmitt, Johannes ; et
al. |
October 31, 2002 |
METHOD AND DEVICE FOR ADJUSTING THE BRAKING AND/OR DRIVE EFFECTS ON
WHEEL OF MOTOR VEHICLES
Abstract
The present invention relates to a method and a device for
adjusting the braking effect and/or driving effect at the wheels of
a motor vehicle. For this purpose, a tire tolerance adjustment has
at least two different operating modes. It is determined whether a
mounted spare wheel or temporary spare wheel is present. One of the
operating modes is selected as a function of the determined
existence of a spare wheel.
Inventors: |
Schmitt, Johannes;
(Markgroeningen, DE) ; Mattern, Klaus-Peter;
(Beilstein, DE) ; Gawlik, Rolf; (Beilstein,
DE) |
Correspondence
Address: |
KENYON & KENYON
ONE BROADWAY
NEW YORK
NY
10004
US
|
Family ID: |
7932659 |
Appl. No.: |
09/913471 |
Filed: |
November 28, 2001 |
PCT Filed: |
December 6, 2000 |
PCT NO: |
PCT/DE00/04341 |
Current U.S.
Class: |
701/70 |
Current CPC
Class: |
B60T 2240/07 20130101;
B60T 2240/08 20130101; B60T 8/173 20130101 |
Class at
Publication: |
701/70 |
International
Class: |
G06G 007/76 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 1999 |
DE |
199 60 337.5 |
Claims
What is claimed is:
1. A method for adjusting the braking and/or driving effect at the
wheels (101ij) of a motor vehicle, having at least two wheels and
having the sensors (105ij), which are assigned to the wheels, and
which generate speed signals (Nij) representing the rotary motions
of the wheels, the speed signals (Nij) being corrected by a
correction, and the braking and/or driving effect being adjusted at
least as a function of the corrected output signals of the sensors,
wherein the correction has at least two different operating modes
(RTA.sub.normal, RTA.sub.quick); and it is determined whether a
mounted temporary spare wheel or spare wheel having a smaller
radius than the remaining wheels is present; one of the modes
(RTA.sub.normal, RTA.sub.quick) is selected as a function of the
ascertained presence of a temporary spare wheel or spare wheel.
2. The method as recited in claim 1, wherein the correction is
performed more quickly in a first operating mode (RTA.sub.quick)
having a smaller filtering time constant than in a second operating
mode (RTA.sub.normal) having a larger filtering time constant.
3. The method as recited in claim 1, wherein the motor vehicle is
driven by a vehicle engine (103), and the correction is performed
in a second operating mode (RTA.sub.normal), as a function of an
engine quantity (Mmot) representing the output torque and/or the
output power of the vehicle engine, and, in a first operating mode
(RTA.sub.quick), independently of the engine quantity.
4. The method as recited in claim 1, wherein it is determined
whether the vehicle is traveling on a curve, and the correction is
performed in a second operating mode (RTA.sub.normal), as a
function of detected cornering, and, in a first operating mode
(RTA.sub.quick), independently of detected cornering.
5. The method as recited in claim 1, wherein the forward speed (V)
of the vehicle is determined, and the correction is performed in a
first operating mode (RTA.sub.quick), at a lower forward speed of
the vehicle than in a second operating mode (RTA.sub.normal).
6. The method as recited in claim 1, wherein the vehicle's forward
speed (V) is detected, and the determination of whether a mounted
temporary spare wheel or spare wheel is present is begun in
response to the exceeding of a predefinable speed threshold value
(SW1).
7. The method as recited in claim 1, wherein the determination of
whether there is a mounted temporary spare wheel or spare wheel is
made such that the wheel having the highest rotational speed is
determined from the speed signals (Nij); a check is performed to
determine whether the rotational speed (Nfast) of the wheel having
the highest rotational speed deviates in a predefinable manner (Tb)
from the rotational speed of at least one other wheel (Nref), in
particular of the wheel mounted on the same vehicle axle; it is
determined from the differences in the rotational speeds of the
wheels on the axle on which the wheel having the highest rotational
speed is not mounted whether cornering exists; and the wheel having
the highest rotational speed is determined as the temporary spare
wheel or spare wheel provided that the rotational speed (Nfast) of
this wheel deviates in a predefinable manner and especially for a
predefinable period of time (SW2) from the rotational speed (Nref)
of at least one other wheel, and there is no cornering.
8. The method as recited in claim 1, wherein the mode
(RTA.sub.quick), which is selected in response to the presence of a
temporary spare wheel or spare wheel, is terminated as a function
of a comparison of the corrected output signal of the temporary
spare wheel or the spare wheel, to an output signal of at least one
sensor at another wheel.
9. The method as recited in claim 1, wherein, following termination
of the correction in the operating mode (RTA.sub.quick), which is
selected when a mounted temporary spare wheel or spare wheel is
present, this operating mode (RTA.sub.quick) is blocked for at
least a period of time, in particular, at least until the next time
the vehicle is started.
10. The method as recited in claim 9, wherein the blocking of this
operating mode (RTA.sub.quick) is canceled or not induced when it
is determined during this operating mode (RTA.sub.quick) that
cornering exists.
11. The method as recited in claim 1, wherein a status signal is
generated when a mounted temporary spare wheel or spare wheel is
present, and the functioning of other vehicle systems, such as
systems for anti-lock brake control, for traction control, and/or
for vehicle stability control are modified as a function of this
status signal; provision being made in particular for the status
signal to be supplied via a data line, in particular via a bus
system, to other vehicle systems for controlling and/or regulating
vehicle functions; and/or for the forward speed of the vehicle to
be limited when a temporary spare wheel or a spare wheel is
detected; and/or for the status signal to be used for triggering a
display that can be observed by the driver, in the case of the
presence of a temporary spare wheel or a spare wheel, this being
indicated to the driver; and/or for monitoring means to be provided
via which slip values of the wheels are measured and evaluated in
such a manner that, given the existence of slip values of a
specific, preselectable magnitude, predefinable measures are
introduced, and the monitoring means are deactivated when the
presence of a temporary spare wheel or of a spare wheel is
detected.
12. A device for adjusting the braking and/or driving effect at the
wheels (101ij) of a motor vehicle, having at least two wheels and
having the sensors (105ij), which are assigned to the wheels and
which emit speed signals (Nij) representing the rotary motions of
the wheels, the speed signals (Nij) being corrected by a
correction, and the braking and/or driving effect being adjusted at
least as a function of the corrected output signals of the sensors,
wherein the correction has at least two different operating modes
(RTA.sub.normal, RTA.sub.quick); and it is determined whether a
mounted temporary spare wheel or spare wheel having a smaller
radius than the remaining wheels is present; one of the modes
(RTA.sub.normal, RTA.sub.quick) is selected as a function of the
ascertained presence of a temporary spare wheel or spare wheel.
13. The device as recited in claim 12, wherein the correction is
performed more quickly in a first operating mode (RTA.sub.quick)
having a smaller filtering time constant than in a second operating
mode (RTA.sub.normal) having a larger filtering time constant;
and/or the motor vehicle is driven by a vehicle engine (103), and
the correction is performed in a second operating mode
(RTA.sub.normal) as a function of an engine quantity (Mmot)
representing the output torque and/or the output power of the
vehicle engine and, in a first operating mode (RTA.sub.quick),
independently of the engine quantity; and/or it is determined
whether the vehicle is traveling on a curve, and the correction is
performed in a second operating mode (RTA.sub.normal), as a
function of detected cornering and in a first operating mode
(RTA.sub.quick) independently of detected cornering; and/or the
forward speed (V) of the vehicle is determined, and, in a first
operating mode (RTA.sub.quick), the correction is performed at a
lower forward speed of the vehicle than in a second operating mode
(RTA.sub.normal); and/or the forward speed (V) of the vehicle is
detected, and the determination of whether a mounted temporary
spare wheel or spare wheel is present is begun in response to the
exceeding of a predefinable speed threshold value (SW1).
14. The device as recited in claim 12, wherein the determination of
whether a mounted temporary spare wheel or spare wheel is present
is made such that the wheel having the highest rotational speed is
determined from the speed signals (Nij); a check is performed to
determine whether the rotational speed (Nfast) of the wheel having
the highest rotational speed deviates in a predefinable manner (Tb)
from the rotational speed of at least one other wheel (Nref), in
particular of the wheel mounted on the same vehicle axle; it is
determined from the differences in the rotational speeds of the
wheels on the axle on which the wheel having the highest rotational
speed is not mounted whether cornering exists; and the wheel having
the highest rotational speed is determined as the temporary spare
wheel or spare wheel, provided that the rotational speed (Nfast) of
this wheel deviates in a predefinable manner and especially for a
predefinable period of time (SW2) from the rotational speed (Nref)
of at least one other wheel, and there is no cornering.
15. The device as recited in claim 13, wherein the mode
(RTA.sub.quick), which is selected in response to the presence of a
temporary spare wheel or spare wheel, is terminated as a function
of a comparison of the corrected output signal of the temporary
spare wheel or the spare wheel to an output signal of at least one
sensor at another wheel.
Description
BACKGROUND INFORMATION
[0001] The present invention relates to a method and a device
having the features according to the definitions of the species in
the independent claims.
[0002] A plurality of systems for anti-lock braking control, for
traction control, and/or for vehicle stability in motor vehicles
are known from the related art. These systems generally start from
at least the wheel rotational speeds or the wheel speeds of the
vehicle wheels. However, before the wheel speeds are used for
regulation, they are generally corrected by a so-called tire
tolerance adjustment. Such a regulating system for a motor vehicle
is described in DE 42 30 295 A1, for example, in which errors in
the wheel speeds created by tolerances between the tires are
equalized. Such tolerances are due to different wheel diameters,
for example. For example, a low-pass filtering in conjunction with
a tire tolerance adjustment is described in DE 42 30 295 A1.
[0003] Furthermore, a slip regulation system is known, for example,
from EP 0 510 466 A1, where the wheel rotational speeds are used
for slip formation. To equalize the tire tolerances, the wheel
speeds are corrected. When determining the appropriate correction
factors, possibly existing cornering of the vehicle must be taken
into consideration.
[0004] The variations for adjusting tire tolerances known from the
related art generally require relatively long time intervals. If
the braking regulation and/or driving regulation is acted upon
shortly after the vehicle is started, a slow tire tolerance
adjustment can potentially result in unfavorable conditions.
[0005] If there is tire damage on a motor vehicle, often only a
temporary spare wheel or spare wheel is provided. In contrast to
standard wheels, this temporary spare wheel or spare wheel has a
significantly smaller diameter which is to be taken into
consideration by a tire tolerance adjustment. A detection of such
temporary spare wheels or spare wheels is known from EP 0 449 845
B1, for example.
SUMMARY OF THE INVENTION
[0006] As mentioned, the present invention relates to a method and
a device for adjusting the braking effect and/or driving effect at
the wheels of a motor vehicle. Assigned to the wheels are sensors
that emit speed signals representing the rotary motions of the
wheels. These speed signals are corrected via a correction, i.e.,
the tire tolerance adjustment. The braking and/or driving effect
is/are adjusted at least as a function of corrected sensor speed
signals.
[0007] The essence of the present invention is that the correction,
i.e., the tire tolerance adjustment, has at least two different
modes of operation. Furthermore, it is determined whether a mounted
spare wheel or temporary spare wheel having a smaller diameter than
the remaining wheels is present. One of the operating modes is then
selected in accordance with the present invention, as a function of
the determined existence of a spare wheel.
[0008] According to the present invention, a selection module is
connected in series with and upstream from the actual tire
tolerance adjustment, the selection module selecting a specific
operating mode in response to a temporary spare wheel being
present. This certain operating mode of the tire tolerance
adjustment advantageously enables a particularly quick tire
tolerance adjustment. The actual, slow tire tolerance adjustment,
which is, however, generally more precise, follows the first, quick
tire tolerance adjustment. As a result of this adjustment
algorithm, the rotational speed of a temporary spare wheel or spare
wheel is very quickly adjusted to the other wheel speeds. As a
result of the present invention, the temporary spare wheel
adjustment is carried out in such a manner that the complete
functionality of an anti-lock control system, traction control
system, and/or vehicle stability system or of an electronic braking
force distribution system is already present when braking for the
first time. Thus, no additional measures are necessary.
[0009] In an advantageous embodiment of the present invention, it
is provided that the correction, i.e., the tire tolerance
adjustment, is carried out more quickly in a first operating mode
having a smaller filtering time constant than in a second operating
mode having a larger filtering time constant.
[0010] A further embodiment of the present invention start from the
assumption that the standard, slow tire tolerance adjustment is
carried out as a function of the output torque of the vehicle
engine. This can be inferred, for example, from the document DE 42
30 295 A1 mentioned at the outset. Thus, for the standard, i.e.,
slow, tire tolerance adjustment, a certain condition must be given
for the engine torque in order for the tire tolerance adjustment to
be carried out. For example, the drive torque or the drag torque
acting on the wheels must be sufficiently low. However, this
condition slows the tire tolerance adjustment in cases in which the
engine torque does not satisfy this condition. According to this
embodiment of the present invention, it is provided that the
correction is carried out in a first, quick operation mode of the
tire tolerance adjustment, independently of the engine torque.
[0011] It is further known to attach the tire tolerance adjustment
to the condition that no cornering exists. In an additional
embodiment of the present invention, it is provided that it be
determined whether the vehicle is traveling on a curve. The essence
of this embodiment is that the tire tolerance adjustment is
performed in the first, quick operating mode, independently of
determined cornering.
[0012] In a further embodiment of the present invention, it is
provided that, in the first, quick operating mode, the tire
tolerance adjustment is performed at lower forward speeds of the
vehicle than in a second, slower operating mode.
[0013] However, the determination of whether there is a mounted
temporary spare wheel or spare wheel is advantageously only begun
when a predefinable speed threshold value for the vehicle's forward
speed is exceeded.
[0014] In a further advantageous embodiment of the present
invention, it is provided that the determination of whether there
is a mounted temporary spare wheel or spare wheel occurs in such a
manner that
[0015] the wheel having the highest rotational speed is determined
from the speed signals;
[0016] a check is performed to determine whether the rotational
speed of the wheel having the highest rotational speed deviates in
a predefinable manner from the rotational speed having the speed of
at least one other wheel, in particular of the wheel mounted on the
same vehicle axle;
[0017] it is determined from the differences of the rotational
speeds of the wheels on the axle on which the wheel having the
highest rotational speed is not mounted whether cornering exists;
and
[0018] the wheel having the highest rotational speed is determined
as the temporary spare wheel or spare wheel provided that the
rotational speed of this wheel deviates in a predefinable manner
and especially for a predefinable period of time from the
rotational speed of at least one other wheel, and there is no
cornering.
[0019] In a further embodiment of the present invention, it is
provided that the mode selected when a temporary spare wheel or
spare wheel is present is terminated as a function of the result of
a comparison of the corrected output signal of the temporary spare
wheel or the spare wheel to an output signal of at least one sensor
at another wheel. This is because the quick and tolerant tire
tolerance adjustment is only intended to enable a first, quick
adaptation of the temporary spare wheel to the reference wheel. The
standard tire tolerance adjustment including its release conditions
is to subsequently apply again. The quick and tolerant tire
tolerance adjustment is, therefore, ended when the rotational speed
of the temporary spare wheel or spare wheel deviates less than
1.5%, for example, from the other wheel rotational speeds.
[0020] Additional advantageous embodiments are given in the
dependent claims.
BRIEF DESCRIPTION OF THE DRAWING
[0021] FIG. 1 shows an overview of a block diagram of the present
invention. FIG. 2 shows the basic sequence of the adjustment of the
braking effect and/or driving effect at the wheels, while FIG. 3
shows the detailed sequence of a specific embodiment of the present
invention.
EXEMPLARY EMBODIMENT
[0022] Embodiments of the present invention are described below in
light of the exemplary embodiments.
[0023] FIG. 1 shows a schematic view of a vehicle having vehicle
wheels 101ij. In the following, the index i designates the
association of the corresponding quantity with the rear (i=h) or
the front (i=v) vehicle axle. The index j indicates the association
of the corresponding quantity with the right (j=r) or the left
(j=l) side of the vehicle. Speed sensors 105ij and wheel brake
units 106ij are mounted on vehicle wheels 101ij. Wheel speed
sensors 105ij send their output signals Nij to control unit 104. In
control unit 104, drive signals Bij for wheel brake units 106ij are
formed at least as a function of wheel speed values Nij. This
occurs in a generally known manner, for example, by forming slip
values for individual vehicle wheels 101ij from wheel speeds Nij,
the braking effect and/or the driving effect at the individual
vehicle wheels being subsequently adjusted via signals Bij and/or A
in such a manner that a specific brake slip or drive slip is not
exceeded.
[0024] In addition, the vehicle's drive train is sketched in FIG.
1. In this context, reference numeral 103 designates the vehicle
engine whose output power or output torque or output rotational
speed can be controlled or regulated via control unit 104, using
drive signal A. The output torque of engine 103, which, in engine
management, generally exists as torque signal Mmot, is directed to
control unit 104.
[0025] Vehicle engine 103 is connected to transmission 105 via
clutch 108. Transmission 105 is then connected via differential 102
to the drive gears on the back axle. The output rotational speed of
the transmission is determined via speed sensor 107. Corrected by
the transmission ratio of differential 102 and/or by the wheel
diameter at the driving wheels, the output rotational speed of the
transmission is a measure of forward speed V of the vehicle.
[0026] The adjustment of the braking and/or driving effect at
vehicle wheels 101ij via control unit 104 is shown schematically in
FIG. 2. After initial step 201, wheel speed signals Nij and
additional signals are detected in following step 202. In step 203,
the drive signals for wheel brakes 106ij (drive signal Bij) and
drive signal A for vehicle engine 103 are formed at least as a
function of detected wheel speed signals Nij. This is indicated in
step 203 by functional dependence F and G. After final step 204,
the sequence shown in FIG. 2 is restarted. The formation of drive
signals Bij and A is described frequently in the related art and
will not be explained in greater detail here.
[0027] FIG. 3 shows a detailed sequence of an exemplary embodiment
according to the present invention.
[0028] After start step 301, counter value T is first set to zero
in step 302. In step 303, wheel speeds Nij or the vehicle's forward
speed is/are determined.
[0029] In query 304, forward speed V of the vehicle is compared to
a threshold value SW1. If forward speed V of the vehicle does not
exceed threshold value SW1, the following conditions for quick tire
tolerance adjustment 309 are not checked. In this case, standard
tire tolerance adjustment 310 including its special acceptance
conditions (e.g. conditions for the engine torque, cornering, etc.)
is carried out.
[0030] However, if forward speed V of the vehicle does exceed
threshold value SW1, the vehicle is traveling at a sufficiently
high vehicle speed, whereupon the fastest rotating wheel is
determined in step 305. This wheel exhibits non-corrected wheel
speed Nfast. Furthermore, non-corrected wheel speed Nref of the
other wheel of the same axle (reference wheel) is loaded into a
temporary register for further processing.
[0031] In addition, a tolerance band Tb is formed in step 305.
Predefinable threshold values SWu and SWo are provided for this
purpose. Using wheel speed Nref of the reference wheel, tolerance
band Tb is calculated in correspondence with the possibly mounted
temporary spare wheels. For this purpose, a lower value SWu as well
as an upper value SWo are added to wheel speed Nref of the
reference wheel. In this manner, one obtains tolerance band Tb:
Tb=[(Nref+SWu);(Nref+SWo)]
[0032] Step 306 determines whether speed Nfast of the fastest wheel
is within tolerance band Tb. If this is not the case, the fastest
wheel is obviously not a temporary spare tire or spare tire.
Standard tire tolerance adjustment 310 is then performed.
[0033] However, if step 306 determines that rotational speed Nfast
is within the tolerance band, this wheel is a temporary spare wheel
or a spare wheel. Subsequent step 307 then determines whether the
vehicle is cornering at the moment. Cornering is checked for in
light of the following condition.
[0034] The difference in the wheel speeds of the axle on which the
supposed temporary spare wheel (fastest wheel) is not located must
be less than or equal to a certain threshold value. If this is the
case, it can be assumed that the vehicle is traveling on a curve
having a larger radius of curve or is traveling straight. In this
case, step 308 is the next step. However, if the vehicle is
traveling on a curve having a small radius of curve, standard tire
tolerance adjustment 310 including its special acceptance
conditions is performed. If it is determined, for example, that the
temporary spare wheel (fastest wheel) is located on the front axle,
the amount of the rotational speed difference
.DELTA.N=.vertline.(Nhr-Nhl).vertline. of the back wheels is
compared to a relatively small threshold value SW3, which can, for
example, be selected as a function of the vehicle's forward speed,
in order to detect curves. If rotational speed difference .DELTA.N
is less than threshold value SW3, there is essentially no
cornering. If rotational speed difference .DELTA.N exceeds
threshold value SW3, there is cornering.
[0035] To detect curves in step 307, a steering angle signal, a
transverse acceleration signal, and/or a yaw angle signal can be
used, provided that the appropriate sensors are present in or on
the vehicle.
[0036] Query 308 determines whether counter value T exceeds a
corresponding, predefinable threshold value SW2. If this is not the
case, the counter value is increased by one counter value in step
311, and the already described sequence is restarted with step
303.
[0037] However, if step 308 determines that the counter value
exceeds threshold value SW2, the conditions for quick tire
tolerance adjustment 309 have been present for a sufficient length
of time. In this case, quick tire tolerance adjustment 309 is
performed.
[0038] The quick and tolerant tire tolerance adjustment 309 is only
intended to enable a first, quick adaptation of the temporary spare
wheel to the reference wheel. The standard tire tolerance
adjustment including its release conditions is to subsequently
apply again. This is achieved in that wheel speed Nfast of the
temporary spare wheel is corrected to form corrected wheel speed
Nfast,kor in step 313. In subsequent step 314, corrected value
Nfast,kor is compared to rotational speed Nref of the reference
wheel. As long as corrected value Nfast,kor is greater than
reference rotational speed Nref, quick tire tolerance adjustment
309 is maintained. However, as soon as corrected value Nfast,kor
exceeds rotational speed Nref of the reference rotational speed,
the quick tire tolerance adjustment is terminated in final step
312. In step 314, the difference (Nfast,kor-Nref) can also be
compared to a threshold value that is 1.5% of Nref, for
example.
[0039] After the correction is terminated in operating mode
RTA.sub.quick, this operating mode RTA.sub.quick is blocked for at
least a period of time. In particular, it can be provided that the
blocking is maintained at least until the vehicle is started again.
In this manner, a further, possibly incorrect, quick adjustment
during the remaining drive is prevented. However, the blocking of
this operating mode RTA.sub.quick can be canceled or not induced
when the existence of cornering is detected during operating mode
RTA.sub.quick. In this case, mode RTA.sub.quick continues to be
allowed.
[0040] According to the present invention, a software module
detects the typical speed difference of a temporary spare wheel or
spare wheel with respect to other wheel rotational speeds. Certain
conditions are then checked in accordance with the present
invention:
[0041] The vehicle is traveling at a significantly high speed
(query 303).
[0042] No additional wheel satisfies the temporary spare wheel or
spare wheel condition.
[0043] A time criterion is satisfied (query 308).
[0044] If these conditions are satisfied, the subsequent tire
tolerance adjustment module is modified, so that it is enabled as
being tolerant and is quickly carried out until the temporary spare
wheel is adjusted to a certain percentage. This occurs such
that
[0045] the tire tolerance adjustment is begun upon initiating
travel;
[0046] the tire tolerance adjustment is carried out independently
of the engine torque;
[0047] the tire tolerance adjustment is carried out more quickly
(smaller filtering time constant); and
[0048] the tire tolerance adjustment is carried out in a
curve-tolerant manner, i.e., independently of whether cornering
exists.
[0049] The quick and tolerant, tire tolerance adjustment is
terminated when the rotational speed of the temporary spare wheel
or spare wheel deviates less than 1.5%, for example, from the other
wheel rotational speeds. By way of exception, the quick tire
tolerance adjustment is repeated after cornering when this quick
tire tolerance adjustment was performed before or during
cornering.
[0050] As a result of the present invention, the temporary spare
wheel adjustment is carried out in such a manner that the complete
functionality of an anti-lock control system or of an electronic
braking force distribution system is already present when braking
for the first time. Thus, no additional measures are necessary.
[0051] In a further embodiment of the present invention, it is
provided that a status signal is generated when a mounted temporary
spare wheel or spare wheel is present. The functioning of other
vehicle systems, such as systems for anti-lock brake control, for
traction control, and/or for vehicle stability are modified as a
function of this status signal.
[0052] In this context, it is particularly provided that the status
signal is supplied via a data line, in particular via a bus system
(CAN bus, Controller Area Network), to other vehicle systems for
controlling and/or regulating vehicle functions. Thus, for example,
provision can be made for the vehicle's forward speed to be limited
when a temporary spare wheel or a spare wheel is detected.
[0053] Furthermore, the status signal can be used for triggering a
display that can be observed by the driver. In the event that a
temporary spare wheel or a spare wheel is present, this is
displayed to the driver. As a result, the driver is continually
reminded that a temporary spare wheel or a spare wheel is
mounted.
[0054] Furthermore, monitoring means can be provided via which slip
values of the wheels are measured and evaluated in such a manner
that, given the existence of slip values of a certain,
preselectable magnitude, predefinable measures are introduced. For
example, in the case of such sustained slip monitoring, it can be
provided that braking and/or driving systems are switched off when
sufficiently high slip values have been present for a sufficient
period of time. If these monitoring means evaluate the uncorrected
wheel rotational speeds, the monitoring means are deactivated when
a temporary spare wheel or a spare wheel is detected.
* * * * *