Method for detecting a faulty arrangement of a sensor module in a sensor module holder in a tire monitoring system of a vehicle

Abstract

Method for detecting a faulty arrangement of a sensor module (12) in a sensor module holder (13) in a tire (2) of a vehicle (1) equipped with a tire monitoring system, wherein the tire monitoring system has several sensor modules (12) arranged in a respective sensor module holder (13) of a respective tire (2) of the vehicle (1), each of which determines an operating parameter (FPQ) of the respective tire (2) depending on a sensorially detected acceleration at the arrangement point (4) of the sensor module (12) and transmits wirelessly to a receiving and evaluation unit (30, 40) arranged in the vehicle (1), wherein a faulty arrangement of one of the sensor modules (12) in the relevant sensor module holder (13) is detected by comparing the operating parameters (FPQ) determined by the sensor modules (12) and determining that for this sensor module (12) there exists a deviation of the operating parameter (FPQ) from an expected operating parameter (FPQ) that depends on the speed of the vehicle (1). characterized by the fact that the deviation from the expected operating parameter (FPQ) shows a dependence on the current speed of the vehicle (1), and that the detection of a deviation that changes with varying speed of the vehicle (1) is provided for.

Description

[0001] The present invention relates to the field of tire monitoring systems in vehicles equipped with tires.

[0002] Tire monitoring systems are frequently used, for example, in modern road vehicles (e.g., cars, trucks, etc.) and typically comprise several sensor modules arranged in a respective sensor module holder of a respective tire of the vehicle, which each determine at least one operating parameter of the respective tire (e.g., tire pressure, tire temperature, etc.) depending on at least one sensor-detected variable (e.g., pressure, temperature, acceleration, etc.) and transmit it wirelessly to a receiving and evaluation device arranged in the vehicle.

[0003] The radio transmissions, mostly in the form of digital data telegrams, usually occur from time to time, according to a transmission strategy defined in the sensor modules.

[0004] For example, one of the sensor-detected variables can be used directly as an operating parameter, which is useful for the variables “pressure” and “temperature,” for example, in order to transmit the corresponding tire operating parameters “tire pressure” or “tire temperature” to the receiving and evaluation device located in the vehicle.

[0005] In contrast, in many known tire monitoring systems, an "acceleration" (e.g. radial acceleration) detected by the sensor modules is generally not used as such as an operating parameter to be transmitted, but the sensor modules determine one or more operating parameters based on an evaluation of a temporal progression of the acceleration and, if necessary, taking into account one or more other variables, which then depend on the detected acceleration but do not represent this acceleration as such.

[0006] For example, the “rotational speed” of the vehicle wheel or tire in question is often determined from the acceleration detected by the sensors and included in the data transmissions as an operating parameter.

[0007] In addition, it is known, for example, to determine an operating parameter that is representative of the “length of a tire contact patch” of the tire in question (often referred to as “tire footprint”) depending on the acceleration detected by the sensor.

[0008] Finally, tire monitoring systems are already known in which, among other things, operating parameters such as "tire tread depth", "tire load", "road surface condition", "risk of aquaplaning", etc. can be monitored for the individual tires of the vehicle based on the acceleration detected by sensors.

[0009] The sensor module holders arranged in the individual tires advantageously allow for easy subsequent replacement of a sensor module, e.g., in the event of a defect in the sensor module or in the event of a depleted electrical battery of the sensor module.

[0010] However, it has been found that the use of such sensor module mounts is disadvantageous: incorrect (e.g., slightly tilted) positioning of a sensor module in a sensor module mount can significantly distort the results of a sensor-based acceleration detection. As a result, all operating parameters determined based on the detected acceleration can also be distorted, which is very detrimental.

[0011] DE 102 43 441 A1 discloses a transponder embedded in a substrate, which is connected to the inner side of a tire via a connecting or holding device. DE 10 2011 003 134 A1 discloses an arrangement of a tire pressure sensor unit on the inner wall of the tread of a vehicle tire in a holding device for the tire pressure sensor unit connected to this inner wall.

[0012] From WO 2018 / 042112 A1 a method for detecting an incorrect arrangement of a sensor module in a sensor module holder in a tire is known.

[0013] US 2017 / 241566 A1 describes a method for determining the need to replace a snap-in valve on a vehicle tire. This method involves calculating a pressure or force on the snap-in valve at specific rotational speeds to predict signs of aging.

[0014] DE 10 2009 044 573 A1 describes a method for detecting a tire module for vehicles that has detached from the inner side of a tire. This involves measuring the centrifugal acceleration acting on a tire module of the vehicle using an acceleration sensor located in the tire module. The acceleration values ​​are analyzed during vehicle acceleration during the starting phase or at constant low vehicle speeds. A statistically significant standard deviation compared to a tire module that has not detached from the inner side of the tire is used as a test benchmark.

[0015] DE 10 2016 202 382 A1 also discloses a method for detecting a sensor device that is not properly attached to a vehicle tire.

[0016] It is an object of the present invention to improve the reliability of a tire monitoring system with regard to the case, which cannot be ruled out in practice, of an incorrect arrangement of a sensor module in the relevant sensor module holder.

[0017] The stated object is achieved according to the invention by a method according to claim 1 and a tire monitoring system according to claim 9. The dependent claims are directed to advantageous developments of the invention.

[0018] The basic idea of ​​the invention is to detect an incorrect arrangement of a sensor module.

[0019] In the invention, detection of an incorrect arrangement of one of the sensor modules in the relevant sensor module holder is achieved by determining, based on a comparison of the operating parameters determined by the sensor modules as a function of the sensor-detected accelerations at the sensor module arrangement locations, that for this sensor module, a deviation of the operating parameter, dependent on the vehicle speed, exists from an operating parameter to be expected for this sensor module (assuming proper arrangement in the sensor module holder). The deviation from the expected operating parameter indicates a dependence on the current speed of the vehicle, and the detection of a deviation that changes with varying vehicle speed is provided.

[0020] An incorrect arrangement of a sensor module means that the sensor module is not fixed in the intended position and / or intended orientation by the sensor module holder in the tire.

[0021] This could, for example, involve the rather unlikely case of a "loose" (movable) mount, or the more likely case of a mount that is more or less stable but incorrect in terms of position and / or orientation. In particular, the invention can be used to detect a sensor module that is installed tilted in the sensor module mount.

[0022] For most practical misalignments, it has been found that the resulting distortions of (at least one) operating parameter based on the detected acceleration (deviation from the expected operating parameter) indicate a dependence on the current vehicle speed. Therefore, the detection of a deviation dependent on the vehicle speed provided by the invention has a particularly high degree of significance with regard to the misalignment to be detected.

[0023] One reason for the speed dependence of the deviation of the determined operating parameter is presumably that the speed-dependent centrifugal force acting on the sensor module (and the sensor module holder) in conjunction with a generally high degree of flexibility of typical tire materials (e.g. rubber or the like) and / or a sensor module holder (often made of rubber or the like) influences the position and / or orientation of the incorrectly arranged sensor module accordingly, i.e. changes it depending on the speed.

[0024] In this respect, the method according to the invention is particularly advantageous if the sensor module holders are each designed as a receptacle made of an elastic material (rubber or the like) for inserting the respective sensor module.

[0025] The receptacle can, for example, define an at least approximately cylindrical receiving space into which a sensor module with a suitably dimensioned cylindrical shape (overall or at least in certain areas) can be inserted. The cylinder axis can, in particular, be provided extending in the radial direction of the tire.

[0026] In one embodiment, it is provided that the sensor module holders are each fastened to an inner side of a tire tread of the respective tire.

[0027] The fastening of the sensor module holders can be realized, for example, by gluing them into the tire.

[0028] In one embodiment, it is provided that the tire monitoring system serves as a tire pressure monitoring system, wherein the sensor modules each detect a pressure in the respective tire and (also) wirelessly transmit the tire pressure of the respective tire to the receiving and evaluation device as a (further) operating parameter.

[0029] In this embodiment, not only is acceleration at the location of the sensor module detected by sensors, but at least also the pressure in the respective tire.

[0030] Alternatively or in addition to detecting the pressure in the respective tire, it can also be provided that the sensor modules each detect a temperature, e.g., to determine a tire temperature as a further operating parameter of the tire and to send it to the vehicle-side receiving and evaluation device.

[0031] In one embodiment, the acceleration sensed by the sensor modules at the location of the respective sensor module comprises a radial acceleration and / or a tangential acceleration. Alternatively or additionally, however, the sensor-sensed acceleration can also comprise at least one differently oriented acceleration or another "type of acceleration" (e.g., mechanical "shock," "vibration," etc.).

[0032] The measurement of radial acceleration has proven particularly advantageous for many applications (e.g. determination of rotational speed and / or length of a tire contact patch and / or tire load).

[0033] In one embodiment, it is provided that the operating parameter determined by the sensor modules is representative of a length of a tire contact patch (“tire footprint”) of the tire in question.

[0034] In this sense, an absolute measurement of this length is representative of the length of the tire contact patch, but also a relative measurement which indicates this length in relation to another dimension that can be determined on the tire in question, such as a tire circumference or a tire diameter.

[0035] In one embodiment, the determined operating parameter indicates the ratio of the length of the tire contact patch to the outer circumference of the tire, hereinafter also referred to as "tire contact quotient" (FPQ).

[0036] In terms of measurement technology, the determination of the tire contact quotient in the relevant sensor module can be realized, for example, by forming the quotient of the time period corresponding to the passage of the sensor module through the tire contact area and the time period corresponding to a full tire rotation (360°).

[0037] In one embodiment, the tire monitoring system in question is used (also) to determine wheel loads acting on the wheels and thus tires of the vehicle.

[0038] For the implementation of such a load monitoring functionality, for example, the use (processing) of the above-mentioned operating parameter, which is representative of a length of a tire contact patch, such as the aforementioned tire contact ratio, may be provided.

[0039] When determining the wheel load on a specific tire, such an operating parameter can be processed, for example, in conjunction with the tire pressure determined for that tire and / or tire information stored in the sensor module of that tire regarding the properties of the tire.

[0040] In one embodiment, the wheel load of the tire in question is determined and transmitted by the sensor module as a (further) operating parameter.

[0041] At very low vehicle speeds, in practice, for example, less than about 10 km / h, speed-dependent effects of the centrifugal force acting on the sensor module tend to be negligible or can only be determined with inaccurate measurement technology.

[0042] At very high vehicle speeds, in practice, for example, greater than approximately 100 km / h, the centrifugal force is relatively large, but even in this case, often only relatively small speed-dependent effects (with regard to the deviation of the determined operating parameter from the expected operating parameter) can be observed due to a certain "saturation" of the influence of the centrifugal force on the position and / or orientation of the sensor module.

[0043] In particular, from this aspect, according to one embodiment, the determination of the deviation is provided in a predetermined sub-range of an overall range of the speed of the vehicle that is intended for operation of the vehicle.

[0044] In one embodiment, the said sub-range is predetermined (e.g., fixed) with a lower limit, which may be, for example, at least 0 km / h, in particular at least 5 km / h, and, for example, at most 60 km / h, in particular at most 50 km / h.

[0045] In one embodiment, the said sub-range is predetermined (e.g., fixed) with an upper limit, which may, for example, be no more than 150 km / h, in particular no more than 100 km / h, and may, for example, be at least 60 km / h, in particular at least 70 km / h.

[0046] Such a focus on only a partial range of vehicle speeds advantageously influences the quality and reliability of the detection provided according to the invention.

[0047] As far as the knowledge of the speed of the vehicle, which is required anyway within the scope of the invention regardless of the latter embodiment, all methods already known from the prior art can be used to determine this vehicle speed.

[0048] In one embodiment of the invention, for example, it is provided that the speed of the vehicle is determined based on a detection of the rotational speed of one or more (e.g. averaging) of the vehicle wheels provided with the tires, wherein each of these detections can in turn be realized by a sensor device arranged on the relevant vehicle wheel in the vehicle and / or based on the sensory detection of the acceleration carried out by the sensor module in the tire of this vehicle wheel.

[0049] Alternatively or in addition to detecting at least one such wheel rotation speed, a satellite-based positioning system (e.g. GPS) can also be used to detect the vehicle speed.

[0050] In one embodiment, it is provided that the detection of a deviation which changes monotonically with varying speed of the vehicle is provided.

[0051] In many cases, this measure also contributes to improving the quality of the detection according to the invention. Since the explained influence of the speed-dependent centrifugal force acting on the sensor module suggests such a monotonic relationship, the detection of such a monotonicity is highly informative for detecting the misalignment of the sensor module.

[0052] In principle, for the determination of a deviation that changes monotonically with varying vehicle speed, both the variant in which an increasing deviation with increasing vehicle speed is used as a criterion for the presence of a misalignment of the sensor module in question and the variant in which a decreasing deviation with increasing vehicle speed is used as such a criterion can be considered.

[0053] The latter variant, which provides for the detection of a deviation that decreases with increasing speed, is particularly well suited for detecting a misalignment of the sensor module that is common in practice, which consists in the sensor module being slightly tilted and / or not properly (fully) recessed in the relevant sensor module holder.

[0054] In this common error case, the tilting and the incorrect distance of the sensor module from the tire material lead to a falsification of the determined operating parameter, particularly at relatively low vehicle speeds, and thus to a relatively large deviation of the operating parameter (from the expected operating parameter), whereas with increasing vehicle speed the sensor module is presumably tending to be straightened up and pressed closer to the tire material or into the sensor module holder due to the greater centrifugal force, whereby the deviation of the determined operating parameter becomes smaller or can no longer be determined as significant.

[0055] In the method according to the invention, the detection of a faulty arrangement is preferably carried out in a parallel processing mode for all sensor modules of the tire monitoring system in question, wherein, based on the comparison of the operating parameters determined by all sensor modules, it is checked for each individual sensor module whether the operating parameter for this sensor module shows a (significant) deviation from the operating parameter to be expected for this sensor module and whether this deviation depends on the speed of the vehicle.

[0056] Given the latter aspect, it is understandable that before a sensor module misalignment can be detected, operating parameters determined for various vehicle speeds must first be collected (stored) and evaluated. As already explained above, it may be possible to collect and evaluate the relevant information only for a sub-range of vehicle speeds that is limited in both directions.

[0057] In one embodiment, the operating parameters used for the evaluation or detection of a misalignment are collected for at least three different speeds of the vehicle.

[0058] In one embodiment, for each speed of the vehicle predetermined by a detection algorithm, at least ten operating parameters (determination results) of each sensor module are collected for evaluation or detection (e.g. carried out using a statistical method).

[0059] In one embodiment, for the evaluation or detection of a misalignment, operating parameters are collected only within a predetermined range of vehicle dynamics states. This range may, for example, provide for the vehicle to travel essentially straight (e.g., lateral acceleration below a predetermined threshold) and / or travel at an essentially constant speed (e.g., longitudinal acceleration below a predetermined threshold).

[0060] As regards the "expected operating parameter" to be determined within the scope of the invention for a specific sensor module, this determination can be made, for example, based on a predetermined mathematical model that describes the operating parameter (tire operating parameter) for all sensor modules as a function of one or more other operating parameters of the tires and / or the vehicle.

[0061] The mathematical model should ideally consider the dependence of the operating parameters for the individual sensor modules on at least the individual tire pressures and the individual wheel loads (on the vehicle wheels equipped with tires). This is because different tire pressures and / or different wheel loads acting on the tires lead to different tire deformation states or tire geometries, which in turn lead to different temporal profiles of the sensor-detected accelerations as the tires roll over the road surface.

[0062] Using the mathematical model, a "plausibility check" can be carried out for each sensor module, for example, to determine whether the operating parameter determined by the sensor module is plausible or not in view of the operating parameters determined by the other sensor modules (and whether a corresponding deviation of the operating parameter has a dependency on the vehicle speed specified by the mathematical model).

[0063] This is explained using the example of a tire monitoring system with sensor modules which, depending on the acceleration detected by the sensors, determine the operating parameter "tire contact quotient" (FPQ), defined as the ratio of the length of the tire contact patch to the outer circumference of the tire in question, and determined by the sensor module, for example, as the ratio between a time period of the "tire contact patch" of the sensor module and the time duration of a complete wheel rotation.

[0064] Assuming further that the vehicle is a two-track, four-wheeled vehicle with four identical tires, each with identical tire pressure and wheel load, traveling straight ahead at a constant speed, it can be expected that the operating parameter determined by the individual sensor modules (here: FPQ) is identical for all sensor modules.

[0065] When checking for a deviation in the operating parameter of a specific sensor module, an average value (e.g., an arithmetic mean) of the operating parameters of the other three sensor modules can be used as the "expected operating parameter" in this situation. If it is determined that a vehicle-speed-dependent deviation of the operating parameter from this expected operating parameter exists for a specific sensor module, this can be assessed accordingly as a faulty positioning of this sensor module in the relevant sensor module holder.

[0066] If the above requirements, such as identical tire pressures, identical wheel loads, etc., are not met, a mathematical model used to determine the expected operating parameter can take this into account (model) appropriately.

[0067] In this regard, it can be considered, for example, that a lower tire pressure in a particular tire (detected by the sensor module in question) leads to a larger tire contact ratio for that tire. Likewise, it can be considered, for example, that when the vehicle corners, depending on the vehicle speed, the tire contact ratios of the tires on the outside of the curve are increased and the tire contact ratios of the tires on the inside of the curve are decreased.

[0068] In a preferred embodiment, the operating parameter to be expected for a specific sensor module is determined based on an averaging of “normalized operating parameters” of the remaining sensor modules, wherein the normalization is provided in such a way that the physically remaining influences caused by different tire pressures and / or different wheel loads and / or the influence of the driving condition (speed, road inclination, steering angle, etc.) are compensated even when all sensor modules are correctly arranged in the sensor module holders.

[0069] In one embodiment, the "expected operating parameter" is determined based on the aforementioned mathematical model, which also takes into account a dependence of the operating parameters for the individual sensor modules on the vehicle speed. For example, a misalignment of the sensor module could be detected in this way if the speed dependence of the operating parameter determined by this sensor module is significantly different from the speed dependence expected according to the model and / or the speed dependence observed for the other tires.

[0070] In one embodiment of the invention, it is provided that the detection of the misalignment is carried out in a program-controlled manner, whereby this can expediently be realized by means of the receiving and evaluation device of the tire monitoring system in question.

[0071] If the receiving and evaluation device of the tire monitoring system does not itself determine the current speed of the vehicle (e.g. based on the accelerations detected by sensors at the locations where the sensor modules are arranged), it can be provided that information about the current vehicle speed is communicated to the receiving and evaluation device from other parts of the vehicle electronics (e.g. wheel sensors and / or GPS device).

[0072] According to a further aspect of the present invention, there is provided a tire monitoring system for a vehicle, comprising: - a plurality of sensor modules arranged in a respective sensor module holder of a respective tire of a vehicle, each of which is designed to determine and wirelessly transmit an operating parameter of the respective tire as a function of a sensor-detected acceleration at the location of the sensor module, and - a receiving and evaluation device arranged in the vehicle for receiving and evaluating the tire operating parameters transmitted by the sensor modules, wherein the receiving and evaluation device is further configured to detect an incorrect arrangement of one of the sensor modules in the relevant sensor module holder by determining, based on a comparison of the operating parameters determined by the sensor modules, that for this sensor module, a deviation of the operating parameter from an operating parameter to be expected for this sensor module exists, which deviation is dependent on the speed of the vehicle. The deviation from the expected operating parameter indicates a dependence on the current speed of the vehicle, and the detection of a deviation that changes with varying vehicle speed is provided.

[0073] The embodiments and special configurations described here for the detection method according to the invention can, individually or in any combination, also be provided in an analogous manner as embodiments or special configurations of the tire monitoring system according to the invention (and vice versa).

[0074] The invention will be further described below using exemplary embodiments with reference to the accompanying drawings. They show: Fig. 1 a schematic side view of a vehicle wheel with a tire in which a sensor module held in a sensor module holder is arranged, Fig. 2 a block diagram of the sensor module of Fig. 1, Fig. 3 is a schematic side view of a detail of the tire of Fig. 1 to illustrate an incorrect arrangement of the sensor module in the sensor module holder, Fig. 4 another schematic view (cross-section) of the detail of Fig. 3, Fig. 5 is a schematic plan view of a vehicle equipped with a tire monitoring system, and Fig. 6 a diagram illustrating the effect of an incorrect arrangement of a sensor module on a tire contact ratio determined by means of this sensor module.

[0075] Fig. 1 shows a vehicle wheel W comprising a rim and a tire 2 mounted on the rim. Rotation of the tire 2 during travel of the vehicle in question is symbolized by the arrow 3.

[0076] In the tire 2, as a component of a tire monitoring system of the vehicle in question, a sensor module 12 is arranged in a sensor module holder 13, wherein the sensor module holder 13 is designed as a receptacle made of an elastic material (e.g. rubber) into which the sensor module 12 is inserted.

[0077] In the illustrated embodiment, the sensor module holder 13 defines a cylindrical receiving space for accommodating a correspondingly cylindrically shaped body of the sensor module 12 and securing it by elastically enclosing the sensor module body. In this example, the sensor module holder 13 is adhesively bonded to the inner side of a tire tread of the tire 2.

[0078] During the journey of the vehicle, the sensor module 12 determines, for example, in particular an operating parameter that is representative of the Fig. 1 is the length L of a tire contact patch of tire 2.

[0079] Fig. 2 shows a block diagram of the sensor module 12, comprising a pressure sensor 14 for detecting a sensor signal “p” representative of a pressure in the tire 2, an acceleration sensor 16 for detecting a sensor signal “a” representative of an acceleration, in the exemplary embodiment the radial acceleration, and a temperature sensor 18 for detecting a sensor signal “T” representative of the temperature inside the tire 2.

[0080] The sensor module 12 further comprises a program-controlled control device 20 (e.g., microcontroller) with an associated memory device 22 for storing a program controlling the operation of the control device 20. The control device 20 receives the aforementioned sensor signals p, T, a and, depending on these sensor signals, determines, in a program-controlled manner, several tire operating parameters, which are included from time to time in a data telegram D generated by the control device 20 and transmitted by means of a radio transmission device 24 in the form of radio transmissions R to a device arranged in the vehicle and in Fig. 1 receiving and evaluation device 30, 40 also shown.

[0081] In this exemplary embodiment, the receiving and evaluation device 30, 40 is formed from a radio receiving device 30 for receiving and decoding the radio transmissions R and an evaluation device 40, which receives the data telegrams D decoded by the radio receiving device 30 via a digital bus system 32 (e.g. CAN bus, LIN bus or the like) and then evaluates them or forwards information obtained therefrom to other parts of a vehicle electronics system.

[0082] In the example shown, the evaluation device 40 is formed by a program-controlled computer unit 42 and an associated memory unit 44 for storing a program that controls the operation of the computer unit 42. In practice, the evaluation device 40 can also be implemented, for example, as a partial functionality of a central control device (ECO) already present in the vehicle in question.

[0083] In the example shown, the tire operating parameters of tire 2, which are transmitted to the receiving and evaluation device 30, 40 by means of the radio transmissions D, are in particular the tire pressure, the tire temperature, the rotational speed and a "tire contact quotient" FPQ of tire 2.

[0084] The tire pressure and the tire temperature are determined directly from the corresponding sensor signals “p” and “T”, whereas the determination of the rotational speed and the tire contact quotient FPQ is based on an evaluation, carried out by the control device 20, of the temporal course of the sensor signal “a” representative of the radial acceleration at the arrangement point 4.

[0085] To determine the rotational speed, it is possible, for example, to evaluate the gravitational component of the sensor signal "a", which changes periodically with each wheel rotation, or, for example, to evaluate the frequency of occurrence of signal characteristics in the sensor signal "a", which arise with each passage of the arrangement point 4 through the so-called "tire contact patch". This also allows the tire contact quotient FPQ to be determined, which is defined here as the quotient between the Fig. 1 drawn length L of the tire contact patch and the total circumference of the tire 2.

[0086] With each “impact” of the sensor module 12 upon entering the tire contact patch and each “lift-off” of the sensor module 12 upon exiting the tire contact patch, typical signal characteristics appear in the sensor signal “a”, so that the operating parameter FPQ can be calculated as the quotient between the time period between impact and lift-off and the time duration of a complete rotation (360°) of the tire 2.

[0087] In addition to the operating parameters already mentioned, further operating parameters can be determined by the control device 20 depending on the sensor-detected variables and transmitted to the receiving and evaluation device 30, 40.

[0088] The Fig. 3 and Fig. 4 illustrate again, using enlarged (not to scale) representations, the arrangement of the sensor module 12 in the sensor module holder 13 at the arrangement point 4 in the tire 2.

[0089] In Fig. 3 illustrates an incorrect arrangement of the sensor module 12 in the sensor module holder 13, which cannot be ruled out in practice. In this example, the sensor module 12 is arranged slightly tilted (at an angle of inclination α) in the circumferential direction of the tire 2.

[0090] Such a misalignment of the sensor module 12 is generally not a problem for determining tire pressure and tire temperature. However, this misalignment can, in principle, falsify all operating parameters determined by the sensor module 12 as a function of the detected acceleration (signal "a"), such as, in this case, the determined tire contact ratio FPQ. The tilted sensor module 12 is no longer capable of detecting the radial acceleration as intended, but in the situation shown, actually detects an acceleration oriented slightly inclined with respect to the radial direction at location 4.

[0091] The Fig. The incorrect arrangement of the sensor module 12 illustrated in Figure 3 leads to a falsification of the sensor's radial acceleration measurement results. This error therefore also impairs the functionality and reliability of the tire monitoring system in which such an incorrectly installed sensor module 12 is integrated.

[0092] The present invention aims to prevent a misalignment of a sensor module such as in Fig. 3, so that, for example, operating parameters supplied by the sensor module in question can be assessed by the receiving and evaluation device as invalid (in whole or in part) and / or can be excluded from further use.

[0093] Fig. Figure 5 shows a vehicle 1 equipped with a tire monitoring system according to the invention, which in the example shown is a two-track, four-wheeled road vehicle (e.g., a passenger car) with two front wheels W1, W2 and two rear wheels W3, W4. The wheels W1 to W4 are each equipped with a tire in which a sensor module 12-1, 12-2, 12-3, or 12-4 is arranged. The associated sensor module holders are shown in Fig. 5 are designated by the reference numbers 13-1 to 13-4.

[0094] The following description of the tire monitoring system from Fig. 5 assume that each of the vehicle wheels W1 to W4 is designed as already described with reference to the Fig. 1 to 4 for the vehicle wheel W ( Fig. 1) and therefore each of the sensor modules 12-1 to 12-4 together with the associated sensor module holders 13-1 to 13-4 are designed and function as described with reference to the Fig. 1 to 4 for components 12 and 13 respectively have already been described.

[0095] The tire monitoring system used in the vehicle 1 comprises the plurality of sensor modules 12-1 to 12-4, each of which is mounted in an associated one of the sensor module holders 13-1 to 13-4 of the respective (in Fig. 5 not shown) of the vehicle 1 and are each designed to determine, depending on, among other things, the acceleration detected by the sensor (here: radial acceleration), several operating parameters of the tire in question, including in particular the "tire contact quotient" FPQ, and to transmit them wirelessly (as radio transmissions R1 to R4).

[0096] Furthermore, the tire monitoring system comprises the receiving and evaluation device 30, 40 arranged in the vehicle 1 for receiving and evaluating the operating parameters sent by the sensor modules 12-1 to 12-4.

[0097] The receiving and evaluation device 30, 40, here consisting of the radio receiving device 30 and the program-controlled evaluation device 40 connected thereto via the communication bus 32, is designed to detect a faulty arrangement of one of the sensor modules 12-1 to 12-4 (cf. e.g. Fig. 3) in the respective sensor module holder 13-1, 13-2, 13-3 or 13-4 by determining, based on a comparison of the tire contact quotients FPQ determined by all sensor modules 12-1 to 12-4, that for this sensor module there is a deviation of the tire contact quotient FPQ from a tire contact quotient FPQ to be expected for this sensor module, which deviation is dependent on the speed of the vehicle 1.

[0098] During this detection, for example, a type of plausibility check can be performed in such a way that, for each of the sensor modules 12-1 to 12-4, it is checked whether the FPQ value supplied by the respective sensor module is plausible or not in view of the FPQ values ​​supplied by the remaining three sensor modules. In the case of a detected implausibility, equivalent to a significant (e.g., above a predetermined threshold) deviation of the FPQ value from an FPQ value to be expected with a proper sensor module arrangement, this is evaluated as a misalignment of the respective sensor module if (the deviation) is dependent on the speed of the vehicle 1.

[0099] To determine the speed of vehicle 1, wheel sensors (speed sensors) 10-1 to 10-4 are used in the illustrated embodiment, each of which is assigned to one of the wheels W1 to W4. Sensor signals S1 to S4 supplied by these wheel sensors 10-1 to 10-4 are transmitted via a cable (e.g., using the digital bus system 32) to the evaluation device 40, which then determines the instantaneous vehicle speed in a conventional manner.

[0100] Based on the knowledge of the current vehicle speed, the evaluation device 40 continuously collects data during the travel of the vehicle 1, including the FPQ values ​​supplied by the sensor modules 12-1 to 12-4, each associated with a respective identification of the supplying sensor module (e.g., encoded in the respective radio transmission R1, R2, R3 or R4) and associated with the speed of the vehicle 1 at the respective time. The evaluation device 40 carries out the detection explained on the basis of this data.

[0101] If, for example, the sensor module 12-4 installed in wheel W4 is incorrectly positioned and the plausibility of the FPQ value supplied by the sensor module 12-4 is checked as part of the detection method, the evaluation device 40 can, for example, determine a deviation of the FPQ value from an expected FPQ value based on the data collected for various vehicle speeds. The expected FPQ value can, for example, be determined according to a predetermined algorithm running in the evaluation device 40, e.g., from (among other things) the FPQ values ​​supplied by the remaining sensor modules 12-1 to 12-3. Before a final determination of the "misalignment," however, it is also checked whether or not the detected deviation depends on the vehicle speed in a manner defined by the detection method (e.g., deviation increases / decreases with increasing vehicle speed).

[0102] Fig. 6 illustrates the effect of a misalignment of a sensor module on the FPQ value determined by this sensor module.

[0103] In Fig. 6, the FPQ value is plotted upwards. The FPQ values ​​represented by dots or a solid line are those of a correctly positioned sensor module. In contrast, the dashed line illustrates the FPQ values ​​of an incorrectly positioned sensor module in the same driving situation.

[0104] In Fig. In Figure 6, the five sub-diagrams "A" to "E" illustrate the dependence of the FPQ value on the wheel load currently acting on the respective tire. The individual sub-diagrams A to E are based on the following wheel loads: 525 kg (A), 600 kg (B), 675 kg (C), 750 kg (D), and 825 kg (E). This shows that the higher the wheel load, the higher the FPQ value.

[0105] Within each of the sub-diagrams A to E, three results for the FPQ value are given, identified by an index i with i = 1, 2, or 3, where the index i is representative of the respective vehicle speed as follows: 40 km / h (i=1), 60 km / h (i=2), and 90 km / h (i=3). This shows that, in the example shown, for the properly positioned sensor module, the FPQ value is somewhat dependent on the vehicle speed. In the example, the FPQ value tends to increase slightly as the vehicle speed increases.

[0106] The FPQ value of the incorrectly positioned sensor module (dashed line) results in a significant deviation from the expected FPQ value (solid line), whereby this deviation depends on the vehicle speed. In the example shown, regardless of the wheel load, the deviation decreases monotonically with increasing vehicle speed in the considered speed range from 40 km / h to 90 km / h.

[0107] In the example shown, this deviation is relatively large at a speed of 40 km / h (i=1) and practically zero at a speed of 90 km / h (i=3).

[0108] Transferred to the Fig.In the exemplary embodiment of a tire monitoring system shown in Figure 5, it can be provided in this tire monitoring system as a criterion for detecting an incorrectly arranged sensor module (18-1, 18-2, 18-3 or 18-4), for example, that in the sub-range from 40 to 90 km / h of the vehicle speed, an FPQ value that decreases monotonically with increasing vehicle speed results for the sensor module in question. List of reference symbols 1 vehicle W vehicle wheels 2 tires 3 wheel rotation 4 Ordering office L Length of the tire contact patch FPQ tire contact quotient 10 wheel sensors 12 sensor modules 13 sensor module holders 14 Pressure sensor p pressure sensor signal 16 Accelerometer a acceleration sensor signal 18 Temperature sensor T temperature sensor signal 20 Control device 22 Storage device 24 radio transmitting device D Data Telegram R radio broadcasts 30 radio receiving device 32 bus system 40 Evaluation device 42 computer unit 44 storage unit

Claims

[1] Method for detecting a faulty arrangement of a sensor module (12) in a sensor module holder (13) in a tire (2) of a vehicle (1) equipped with a tire monitoring system, wherein the tire monitoring system comprises a plurality of sensor modules (12) arranged in a respective sensor module holder (13) of a respective tire (2) of the vehicle (1), each of which determines an operating parameter (FPQ) of the respective tire (2) as a function of a sensor-detected acceleration at the location (4) of the sensor module (12) and transmits it wirelessly to a receiving and evaluation device (30, 40) arranged in the vehicle (1), wherein a detection of a faulty arrangement of one of the sensor modules (12) in the respective sensor module holder (13) is carried out by determining, based on a comparison of the operating parameters (FPQ) determined by the sensor modules (12), that for this sensor module (12) there is a deviation of the operating parameter (FPQ) dependent on the speed of the vehicle (1) from an operating parameter (FPQ) to be expected for this sensor module (12) characterized by , that the deviation from the expected operating parameter (FPQ) shows a dependence on the current speed of the vehicle (1), and that the detection of a deviation which changes with varying speed of the vehicle (1) is provided. [2] Method according to claim 1, wherein the sensor module holders (13) are each designed as a receptacle made of an elastic material for inserting the respective sensor module (12). [3] Method according to one of the preceding claims, wherein the sensor module holders (13) are each fastened to an inner side of a tire tread of the respective tire (2). [4] Method according to one of the preceding claims, wherein the tire monitoring system serves as a tire pressure monitoring system, wherein the sensor modules (12) each detect a pressure in the respective tire (2) and transmit the tire pressure wirelessly to the receiving and evaluation device (30, 40) as an operating parameter (FPQ) of the respective tire (2). [5] Method according to one of the preceding claims, wherein the acceleration detected by the sensor modules (12) at the arrangement point (4) of the respective sensor module (12) comprises a radial acceleration and / or a tangential acceleration. [6] Method according to one of the preceding claims, wherein the operating parameter (FPQ) determined by the sensor modules (12) is representative of a length (L) of a tire contact patch of the tire (2) in question. [7] Method according to one of the preceding claims, wherein the determination of the deviation is provided in a predetermined sub-range of an overall range of the speed of the vehicle (1) which is operationally provided for the vehicle (1). [8] Method according to one of the preceding claims, wherein the determination of a deviation which changes monotonously with varying speed of the vehicle (1) is provided. [9] Tire monitoring system for a vehicle, comprising - a plurality of sensor modules (12) arranged in a respective sensor module holder (13) of a respective tire (2) of a vehicle (1), each of which is designed to determine an operating parameter (FPQ) of the respective tire (2) as a function of a sensor-detected acceleration at the arrangement point (4) of the sensor module (12) and to transmit it wirelessly, - a receiving and evaluation device (30, 40) arranged in the vehicle (1) for receiving and evaluating the operating parameters (FPQ) of the tires (2) sent by the sensor modules (12), wherein the receiving and evaluation device (30, 40) is further designed to detect a faulty arrangement of one of the sensor modules (12) in the respective sensor module holder (13) by determining, based on a comparison of the operating parameters (FPQ) determined by the sensor modules (12), that for this sensor module (12) there is a deviation of the operating parameter (FPQ) from an operating parameter (FPQ) to be expected for this sensor module (12), which deviation is dependent on the speed of the vehicle (1). characterized by , that the deviation from the expected operating parameter (FPQ) shows a dependence on the current speed of the vehicle (1), and that the detection of a deviation which changes with varying speed of the vehicle (1) is provided. [10] Tire monitoring system according to claim 9, wherein the tire monitoring system is designed and arranged to carry out a method according to one of claims 1 to 8.

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