DE102006033589B4 - Method for improving a tire pressure monitoring system - Google Patents

Abstract

Method for improving a tire pressure monitoring system in motor vehicles, the tire pressure monitoring system determining reference values (DIAG, SIDE, AXLE) for determining a pressure loss from values about the rolling circumference of the wheels of the vehicle, characterized in that the respective slip (LEFT, RIGHT ) of the torque-affected drive wheels, at least the slip of a left torque-affected drive wheel (LEFT) and the slip of a right torque-affected drive wheel (RIGHT), depending on the drive torque (M), it is learned that a determination of tire properties by evaluating the dependency of the respective slip of the left and right drive wheel (LEFT, RIGHT) from the drive torque (M) and by evaluating the reference values (DIAG, SIDE, AXLE), and that the tire pressure monitoring system is adapted to tire properties in accordance with the tire properties to increase the detection accuracy of the tire pressure monitoring system.

Description

The invention relates to a method for improving a tire pressure monitoring system according to the preamble of claim 1. Furthermore, the invention relates to a computer program product according to claim 10.

Reliable monitoring of the tire pressure on all wheels of a motor vehicle is of great importance for the safety of the vehicle. There are various approaches for implementing tire pressure monitoring systems.

There are so-called direct measuring tire pressure monitoring systems, for example described in the application DE 199 26 616 C2 which use pressure sensors in the individual tires to determine the respective pressure in the associated wheel. Such systems monitor the tire pressure on all wheels independently.

So-called indirectly measuring tire pressure monitoring systems are also known. From the German patent application DE 100 58 140 A1 a method for detecting a tire pressure loss (DDS: Deflation Detection System) in motor vehicles is known, which makes it possible to determine a tire pressure loss even without pressure sensors solely by comparing the rolling circumferences of the individual wheels. Furthermore is from Scripture WO 2005/072995 A1 a method for indirect tire pressure monitoring is known in which a known indirectly measuring tire pressure monitoring system (DDS) is improved taking into account the natural torsional frequency of the vehicle tires.

Next describes the DE 10 2005 031 156 A1 a method for the automatic initialization of an indirectly measuring tire pressure monitoring system (DDS) which recognizes a pressure loss on a vehicle wheel due to a change in the rolling circumference by comparing learned reference values with continuously newly determined values, the automatic initialization being carried out if the newly learned values are not correspond to the reference values already taught in and there is no pressure loss.

the WO 2005/097525 A1 describes a method for detecting the tire sensitivity, which comprises the steps: determining the tire load F _{tires of} the vehicle, determining wheel speed information of the wheels, determining the tire sensitivity from the change in the wheel speed information as a function of the change in the tire load F _tires .

Furthermore describes the EP 0 773 118 B1 a system for determining a tire pressure loss for a vehicle, wherein a reduction in tire pressure in a vehicle tire is based on a difference in diameter between driven wheels and trailing wheels.

the DE 103 43 247 A1 describes a method for the detection of a µ-split situation, in particular for the improved detection of a tire pressure loss in an indirect tire pressure monitoring system (DDS), which is based on wheel speed information, taking into account the road surface coefficient of friction of the right and left side of the vehicle or the coefficient of friction present on each wheel , in which the influence of the slip is taken into account as a function of the wheel torque, in particular the drive torque, on the driven wheels.

the WO 2004/058519 A1 describes a method for improving an indirectly measuring tire pressure detection system, such as in particular a pressure loss detection method based on wheel speed information (DDS), in which the determination of reference values is made dependent on driving parameters, with a two or more-dimensional completely closed driving parameter space being generated within the currently determined reference values be admitted as valid.

Next describes the DE 198 07 880 A1 a method and a device for determining the tire air pressure of the wheels of a motor vehicle using pairs of tire circumferential force / slip measured value pairs for at least one driven wheel that are recorded during ongoing driving operation.

the WO 95/12498 A1 describes a method for tire pressure monitoring by comparing and evaluating the rotational speeds of the individual vehicle wheels, which is based on the formation of speed correction factors K (t, FS).

Finally describes the DE 44 00 913 B4 a method for determining a loss of inflation pressure in a tire on a driven axle of a motor vehicle, in which the rotational speeds of the wheels are measured and slip values for the driven wheels are calculated therefrom, characterized in that wheel drive forces of the vehicle and associated slip values are determined in the form of pairs of values belonging to one another and from this a wheel drive force / slip characteristic is determined and that a warning signal is generated when a maximum limit value for the gradient of the wheel drive force / slip characteristic is exceeded.

The object of the invention is to provide a method which improves an indirectly measuring tire pressure monitoring system or a combined tire pressure monitoring system which contains an indirect and a direct measuring tire pressure monitoring system.

This object is achieved according to the invention by the method according to claim 1.

The invention is based on the idea of learning the respective slip of the torque-affected drive wheels, at least the slip of a left torque-affected drive wheel and the slip of a right torque-affected drive wheel, depending on the drive torque of the drive wheels, and by evaluating the dependency of the respective slip, while driving of the left and right drive wheels from the drive torque and by evaluating reference values, which are determined from values that are related to the rolling circumferences of the wheels of a vehicle, to determine tire properties. Depending on the tire properties, the tire pressure monitoring system is then adapted to tire properties in order to increase the detection accuracy of the tire pressure monitoring system.

Teaching-in of the slip / drive torque value pairs is preferably carried out in certain driving states. This can be, for example, driving at constant speed or driving at low acceleration, during which, as is known, there is drive slip. Teaching-in of value pairs during slip control, e.g. traction control, should preferably not be carried out.

In a preferred embodiment of the invention, the gradients of the associated relationships are determined from the taught-in slip / drive torque value pairs. For this purpose, it is particularly preferable for only the slip / drive torque value pairs to be taken into account in the case of small drive torques of the drive wheels. It is also particularly preferred that the gradients are determined by determining a compensation curve, very particularly preferably a compensation straight line, from the slip-drive torque value pairs.

Furthermore, it is preferred that the reference values are learned and then the wheel position (s) of the wheel (s) with a larger or smaller rolling circumference compared to the other wheels is / are determined by evaluating the size and the sign of the reference values. This provides the tire pressure monitoring system with information about the tire properties, namely with regard to the rolling circumference of the wheels.

In a further preferred embodiment, at least one reference value is taught in as a function of a vehicle transverse acceleration. For this purpose, the vehicle transverse acceleration is advantageously measured with a sensor.

The gradient of the associated relationship for positive and negative vehicle lateral acceleration values is preferably determined from the taught-in reference value / transverse acceleration value pairs. For this purpose, a compensating curve, very particularly preferably a compensating straight line, is particularly preferably determined from the reference value-transverse acceleration value pairs.

It is also preferred that the pressure sensitivity of the rolling circumference of at least one tire, in particular each tire, is determined from the gradients determined from the slip / drive torque value pairs and / or from the gradients determined from the reference value-vehicle transverse acceleration value pairs. This provides the tire pressure monitoring system with further information about the tire properties, namely with regard to the pressure sensitivity of the rolling circumferences of the wheels.

In a further preferred embodiment of the invention, the properties of the tire pressure monitoring system, particularly preferably the warning thresholds for detecting a pressure loss, are automatically adapted to the determined tire properties. This is particularly preferred when the system classifies the determined tire properties as reliable. It is particularly preferred that a separate adaptation of the warning threshold (s) of the wheel is carried out for each drive wheel, and very particularly preferably for each wheel. However, it is also preferred that the tire pressure monitoring system is adapted to the specific tire properties on the basis of a request from the vehicle driver, e.g. by pressing a button.

The learning of the pairs of slip drive torque values and / or the reference values and / or the pairs of reference values and vehicle transverse acceleration values is preferably carried out as a function of the vehicle speed.

The method according to the invention preferably outputs a malfunction display to the vehicle driver if sufficient pressure loss detection is not possible, for example because the rolling circumference is not sufficiently sensitive to pressure for use in an indirect tire pressure monitoring system and / or if the Tire properties cannot be determined and / or if an adaptation of the properties of the tire pressure monitoring system to the tire properties is not possible.

The method according to the invention offers the advantage that tire properties of different tires on the vehicle are also recognized. Furthermore, the tire pressure monitoring system can be automatically adapted to the existing tire properties. This improves the functionality of the tire pressure monitoring system.

Another advantage of the method according to the invention is that a fault display is output if an adjustment or tire pressure monitoring is not possible due to unfavorable tire properties (e.g. worn tires).

The method according to the invention can be carried out in an indirectly measuring tire pressure monitoring system, which is based exclusively on the evaluation of the rolling circumference of the wheels, or in an indirectly measuring tire pressure monitoring system which, in addition to evaluating the rolling circumference, also performs a frequency analysis of the tire vibrations. It is also possible to carry out the method according to the invention in a combined tire pressure monitoring system in which an indirectly measuring tire pressure monitoring system is combined with a directly measuring tire pressure monitoring system.

The invention also relates to a computer program product which defines an algorithm according to the method described above.

Further preferred embodiments of the method according to the invention emerge from the subclaims and the following description of exemplary embodiments on the basis of figures.

• 1 eine Übersicht zur Bestimmung der Radposition eines Rades mit kleinerem/größerem Abrollumfang aus den Vorzeichen von Referenzwerten DIAG, SIDE und AXLE (Tabelle 1),
• 2 eine schematische Darstellung eines Zusammenhangs zwischen einem Schlupf LEFT bzw. RIGHT der Antriebsräder und einem Antriebsmoment M,
• 3 eine schematische Darstellung eines Zusammenhangs zwischen einer Reifenempfindlichkeit C und einer Steigung K_L bzw. K_R, welche sich durch Auswertung des in 1 gezeigten Zusammenhangs ergibt,
• 4 eine schematische Darstellung eines Zusammenhangs zwischen einem Referenzwert DIAG und einer Querbeschleunigung a_Lat eines Fahrzeugs, und
• 5 eine schematische Darstellung eines Zusammenhangs zwischen einer Reifenempfindlichkeit C und einer Steigung K_D1 bzw. K_D2, welche sich durch Auswertung des in 4 gezeigten Zusammenhangs ergibt.

Show it:

• 1 an overview for determining the wheel position of a wheel with a smaller / larger rolling circumference from the signs of reference values DIAG, SIDE and AXLE (Table 1),
• 2 a schematic representation of a relationship between a slip LEFT or RIGHT of the drive wheels and a drive torque M,
• 3 a schematic representation of a relationship between a tire sensitivity C and a gradient K _L or K _R , which is determined by evaluating the in 1 the relationship shown,
• 4th a schematic representation of a relationship between a reference value DIAG and a transverse acceleration a _{Lat of} a vehicle, and
• 5 a schematic representation of a relationship between a tire sensitivity C and a gradient K _D1 or K _D2 , which is determined by evaluating the in 4th shown correlation results.

Indirectly measuring tire pressure monitoring systems use the changes in the tire properties (e.g. the rolling circumference or the characteristic frequency) to detect a loss of tire pressure. The changes in the characteristic reference values that are used for the detection are dependent on the type and condition of the tire. Knowing the tire properties is therefore an important prerequisite for the reliable detection of a pressure loss in the tire.

In particular, it has been shown that the tire sensitivity C, i.e. the change in the rolling circumference of the tire due to a loss of tire pressure, turns out differently for different tires and tire types. If a fixed warning threshold for a specific change in the rolling circumference is used in an indirectly measuring tire pressure system, a warning is issued with regard to a loss of air pressure for different types of tires at different tire pressure levels. This can lead to false warnings or the absence of necessary warnings.

Since not only tires of one type with the same tire properties can be used on a vehicle, but also tires with different tire properties and / or tires of different types and / or tires with different degrees of wear, it is important to recognize such a condition for reliable detection of a pressure loss. The invention therefore provides an improved method for adapting a tire pressure monitoring system to tire properties.

An indirect measuring system can determine whether all vehicle wheels have the same or different rolling circumferences. If the rolling circumference of one or two wheels differs from the others, this can be recognized when learning the indirect measuring system. In this case, the amount of at least one of the learned reference values becomes large. The position of the affected wheel can be determined by comparing the various reference values.

$$\text{SIDE}=\frac{{\text{T}}_{\text{FL}}+{\text{T}}_{\text{RL}}}{{\text{T}}_{\text{FR}}+{\text{T}}_{\text{RR}}}-1$$

$$\text{AXLE}=\frac{{\text{T}}_{\text{FL}}+{\text{T}}_{\text{FR}}}{{\text{T}}_{\text{RL}}+{\text{T}}_{\text{RR}}}-1$$

As an example, the following reference values (DIAG, SIDE, AXLE) are used in an indirectly measuring tire pressure monitoring system: $$\text{DIAG}=\frac{{\text{T}}_{\text{FL}}+{\text{T}}_{\text{RR}}}{{\text{T}}_{\text{FR}}+{\text{T}}_{\text{RL}}}-1$$

$$\text{SIDE}=\frac{{\text{T}}_{\text{FL}}+{\text{T}}_{\text{RL}}}{{\text{T}}_{\text{FR}}+{\text{T}}_{\text{RR}}}-1$$

$$\text{AXLE}=\frac{{\text{T}}_{\text{FL}}+{\text{T}}_{\text{FR}}}{{\text{T}}_{\text{RL}}+{\text{T}}_{\text{RR}}}-1$$

• T_xy: Zeitintervall für eine bestimmte Anzahl von Umdrehungen des entsprechenden Rades xy,
• FL: Rad vorne links,
• FR: Rad vorne rechts,
• RL: Rad hinten links, und
• RR: Rad hinten rechts.

Where:

• T _xy : time interval for a certain number of revolutions of the corresponding wheel xy,
• FL: front left wheel,
• FR: front right wheel,
• RL: rear left wheel, and
• RR: rear right wheel.

First, the reference values DIAG, SIDE and AXLE are taught in. For the learning, the measured values, in particular at the same or close speeds and / or the same or close wheel torques, are collected and the mean values are calculated. Learning is only stopped when the results are significant (e.g. when they have a small standard deviation). The learned values are then saved.

If all wheels have the same rolling circumference, the amounts of the learned reference values become small.

If a wheel has a significantly larger or smaller rolling circumference than the other wheels, the amounts of the learned reference values become large. The position of the affected wheel is determined from an analysis of the signs of the reference values (e.g. with a drive torque of zero, M = 0) (see Table 1 in 1 ).

If two different pairs of tires have been mounted on the vehicle, the amount of only one learned reference value DIAG, SIDE or AXLE, e.g. with a drive torque of zero (M = 0), becomes large. The signs of the reference values then indicate the positions of the larger and smaller tires. If, for example, the reference value DIAG is positive and large, but SIDE and AXLE are close to zero, the "smaller" wheels are attached to the front left and rear right of the vehicle. If the reference value AXLE is positive, but the amounts of DIAG and SIDE are small, the “smaller” wheels are fitted in the front left and front right. If the reference value SIDE is positive and large, the amounts of DIAG and AXLE are small, the “smaller” wheels are fitted at the front left and rear left.

If the situation arises that the wheels have different rolling circumferences, the parameters of the system, e.g. the warning thresholds for recognizing a loss of pressure, are changed on the basis of the situation analysis, in particular with the help of the specific tire sensitivities C (see description below), to ensure that To be able to recognize the pressure level prescribed for the system. The system adapts itself to the current situation. If, on the basis of the situation analysis, it is recognized that the pressure level prescribed for the system cannot be recognized, the fault display is output (e.g. fault warning lamp).

Even if all wheels have the same rolling circumference, the wheels can otherwise have different tire properties, in particular different tire sensitivities C. The situation analysis described in the previous paragraph with subsequent adaptation of the tire pressure monitoring system to the current situation and / or output of a fault display must then also be carried out.

C wird als Empfindlichkeit des Rades bei Druckverlust oder auch kurz als Reifenempfindlichkeit bezeichnet. C gibt die Veränderung des Abrollumfangs des Reifens aufgrund eines Reifendruckverlustes an.The change in the tire rolling circumference ΔD due to a loss of air pressure is proportional to the loss of air pressure ΔP: $$\mathrm{\Delta }\text{D.}=\text{C.}*\mathrm{\Delta }\text{P.}$$

C is referred to as the sensitivity of the wheel in the event of pressure loss or, for short, tire sensitivity. C indicates the change in the rolling circumference of the tire due to a loss of tire pressure.

$$\text{RIGHT}=\frac{{\text{T}}_{\text{FR}}-{\text{T}}_{\text{RR}}}{{\text{T}}_{\text{RR}}}$$

According to the example, the tire sensitivity of each drive wheel is recognized via the dependency of the slip of the drive wheels (LEFT: slip of the left drive wheel, RIGHT: slip of the right drive wheel) on the wheel torque M (drive torque). The slip is calculated as follows: $$\text{LEFT}=\frac{{\text{T}}_{\text{FL}}-{\text{T}}_{\text{RL}}}{{\text{T}}_{\text{RL}}}$$

$$\text{RIGHT}=\frac{{\text{T}}_{\text{FR}}-{\text{T}}_{\text{RR}}}{{\text{T}}_{\text{RR}}}$$

The dependence of the slip of the drive wheels LEFT or RIGHT on the wheel torque M. is approximated using a straight line for small wheel torques. This is in 2 shown schematically.

$$\text{RIGHT}={\text{RIGHT}}_0+{\text{K}}_{\text{R}}*\text{M}$$

The following applies to a rear-wheel drive vehicle: $$\text{LEFT}={\text{LEFT}}_0+{\text{K}}_{\text{L.}}*\text{M.}$$

$$\text{RIGHT}={\text{RIGHT}}_0+{\text{K}}_{\text{R.}}*\text{M.}$$

$$\text{RIGHT}={\text{RIGHT}}_0-{\text{K}}_{\text{R}}*\text{M}$$

LEFTo und RIGHT₀ beschreiben hierbei die Schlupfwerte der angetriebenen Räder bei einem Antriebsmoment von Null (M = 0, entspricht freirollenden Antriebsräder), K_L und K_R sind die Steigungen der Geraden Schlupf LEFT als Funktion des Antriebsmoments M und Schlupf RIGHT als Funktion des Antriebsmoments M.The following applies to a front-wheel drive vehicle: $$\text{LEFT}={\text{LEFT}}_0-{\text{K}}_{\text{L.}}*\text{M.}$$

$$\text{RIGHT}={\text{RIGHT}}_0-{\text{K}}_{\text{R.}}*\text{M.}$$

LEFTo and RIGHT ₀ describe the slip values of the driven wheels with a drive torque of zero (M = 0, corresponds to free rolling drive wheels), K _L and K _R are the gradients of the straight line Slip LEFT as a function of the drive torque M and slip RIGHT as a function of the drive torque M.

It has been shown that the sensitivity of the wheel at pressure loss C _{correlates with the gradients K L} (K _R ). This is in 3 shown schematically.

$$\text{DIAG}={\text{DIAG}}_0+{\text{K}}_{\text{D2}}*{\text{a}}_{\text{Lat}}{\text{ a}}_{\text{Lat}}<0$$

In a further preferred embodiment, the dependence of the reference value DIAG on the transverse acceleration a _{Lat of} the vehicle is also used to determine the sensitivity of the wheels in the event of a pressure loss C. The following applies: $$\text{DIAG}={\text{DIAG}}_0+{\text{K}}_{\text{D1}}*{\text{a}}_{\text{Lat}}{\text{a}}_{\text{Lat}}>0$$

$$\text{DIAG}={\text{DIAG}}_0+{\text{K}}_{\text{D2}}*{\text{a}}_{\text{Lat}}{\text{a}}_{\text{Lat}}<0$$

DIAG ₀ describes the value of the reference value DIAG with a transverse acceleration of zero (a _Lat = 0), K _D1 and K _D2 are the gradients of the straight line Reference value DIAG as a function of the transverse acceleration a _Lat for positive (a _Lat > 0) and negative ( a _Lat <0) lateral accelerations. These relationships are shown schematically in 4th shown.

The gradients K _D1 and K _{D2 of} the straight line reference value DIAG as a function of the transverse acceleration a _Lat correlate with the sensitivity of the wheels in the event of a pressure loss C. This is in FIG 5 shown schematically.

These findings are used to determine the tire properties and to set the detection thresholds of the indirectly measuring tire pressure monitoring system. For this purpose, the variables LEFT, RIGHT and DIAG are taught in first. For learning, value pairs are formed from the corresponding values LEFT (RIGHT) and the wheel torques M as well as the corresponding values DIAG and the lateral accelerations a _Lat . A regression line (equation (4), (5) or (6)) is calculated using the least squares method. Learning is only ended when the corresponding regression line is significant (eg when it shows a small standard deviation). The learned values K _L , K _R and LEFT ₀ , RIGHT ₀ as well as K _D1 , K _D2 and DIAG ₀ are saved.

It is advisable to carry out this learning process taking into account the vehicle speed, e.g. in speed intervals.

The slopes K _L and K _R or K _D1 and K _D2 are then compared with one another. If K _L and K _{R are} not the same, then it is recognized that the tires on the drive axle are different, even if these tires have the same dimensions. If K _L and K _{R are the} same, but K _D1 and K _D2 are not the same, then it is recognized that the tires on the non-driven (free rolling) axle are different, even if these tires have the same dimensions.

The warning thresholds of the indirectly measuring tire pressure monitoring system (DDS) are adjusted separately for each drive wheel or wheel.

The sensitivities of the tires C on the non-driven (free rolling) axle can also be determined, for example, by analyzing the characteristic frequencies of the tire vibrations.

If, for example, it is recognized that there are tires with different properties on the vehicle, the indirectly measuring tire pressure monitoring system is adapted to this situation. In other words, using the method according to the example, the different tire properties are determined separately and the air pressure monitoring is carried out as a function of the tire properties. If it is not possible to adapt the indirectly measuring tire pressure monitoring system to the tires with different properties, a fault display is output, for example, to inform the driver that reliable and / or required / desired pressure loss detection is not possible.

When combining a directly measuring tire pressure monitoring system with an indirectly measuring tire pressure monitoring system (a so-called hybrid TPMS), knowledge of the tire properties is also of great importance, since the detection thresholds and other parameters of the tire pressure monitoring system are adapted to the tire properties, which improves the detection of a pressure loss will. If it is recognized that the properties of at least one wheel are not favorable for the system (hybrid TPMS), or the recognition of a certain pressure loss level (e.g. 75% of the pressure of a cold tire) cannot be fulfilled for the system, a Fault display output (e.g. fault warning lamp).

The fault display is also output if a tire pressure monitoring system is not able to determine the tire properties.

Claims (10)

Method for improving a tire pressure monitoring system in motor vehicles, the tire pressure monitoring system determining reference values (DIAG, SIDE, AXLE) for determining a pressure loss from values about the rolling circumference of the wheels of the vehicle, characterized in that the respective slip (LEFT, RIGHT ) of the torque-affected drive wheels, at least the slip of a left torque-affected drive wheel (LEFT) and the slip of a right torque-affected drive wheel (RIGHT), depending on the drive torque (M), it is learned that a determination of tire properties by evaluating the dependency of the respective slip of the left and right drive wheel (LEFT, RIGHT) is carried out from the drive torque (M) and by evaluating the reference values (DIAG, SIDE, AXLE), and that the tire pressure monitoring system is adapted to tire properties in accordance with the tire properties d to increase the detection accuracy of the tire pressure monitoring system. Procedure according to Claim 1 , characterized _{in that slopes (K L} , K _R ) of the associated relationships, in particular in the case of small drive torques (M) of the drive wheels, are determined from the taught-in slip drive torque value pairs. Procedure according to Claim 1 or 2 , characterized in that the reference values (DIAG, SIDE, AXLE), in particular with a drive torque of the wheels of zero, are learned and the wheel position (FL, FR, RL, RR) of the wheel (s) with a larger or smaller rolling circumference compared to the other wheels. Method according to at least one of the Claims 1 until 3 , characterized in that at least one reference value (DIAG) is learned as _{a function of a vehicle transverse acceleration (a Lat).} Procedure according to Claim 4 , characterized _{in that a slope (K D1} , K _D2 ) of the associated relationship for positive and negative vehicle transverse acceleration values is determined from the taught-in reference value-vehicle transverse acceleration value pairs. Method according to at least one of the Claims 2 until 5 , characterized in that the pressure sensitivity of the rolling circumference (C) of at least one tire, in particular each tire, from the gradients (K _L , K _R ) determined from the slip-drive torque value pairs and / or from the reference value-vehicle transverse acceleration value pairs certain slopes (K _D1 , K _D2 ) is determined. Method according to at least one of the Claims 1 until 6th , characterized in that properties of the tire pressure monitoring system, in particular warning thresholds for detecting a pressure loss, are automatically adapted to the determined tire properties, in particular the property of having a larger or smaller rolling circumference and / or the pressure sensitivity of the rolling circumference (C). Method according to at least one of the Claims 1 until 7th , characterized in that the slip drive torque value pairs and / or the reference values (DIAG, SIDE, AXLE) and / or the reference value-vehicle transverse acceleration value pairs are learned as a function of the vehicle speed. Method according to at least one of the Claims 1 until 8th , characterized in that a fault display is issued to the vehicle driver if sufficient pressure loss detection, in particular due to insufficient pressure sensitivity of the rolling circumference for use in an indirect tire pressure monitoring system, is not possible and / or if the tire properties cannot be determined and / or if an adaptation of the properties of the tire pressure monitoring system to the tire properties is not possible. Computer program product, characterized in that it has an algorithm defines which a method according to at least one of Claims 1 until 9 includes.

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