DE102018205703A1 - Electronic tire module for a tire monitoring system of a vehicle - Google Patents

Abstract

The invention relates to an electronic tire module (12) for a vehicle tire monitoring system (10), comprising: module electronics (30) for detecting at least one tire operating parameter of a tire (3) when the tire module (12) is disposed in the tire (3) and generating and wirelessly transmitting data signals (D) in response to a result of the detection of the at least one tire operating parameter; and a module housing (34) housing the module electronics (30). In order to be able to detect a "sudden loss of tire pressure" of the tire (3), a module cavity (36) is formed in the module housing (34) and is connected to an environment of the tire module (12) via an air flow passage (38) Tire module (12) has a sensor device (18) accommodated in the module housing (34) and designed to move a predetermined amount of air flow out of the module cavity (36) via the air flow passage (38) into the environment of the tire module (12). to detect and output a corresponding flow detection signal (f) to the module electronics (30) for detecting the sudden loss of tire pressure.

Description

The present invention relates to an electronic tire module for a tire monitoring system of a vehicle, according to the preamble of claim 1. Furthermore, the invention relates to a tire monitoring system comprising such tire modules, and to a vehicle having a tire monitoring system comprising such tire modules.

• - eine Modulelektronik zum Erfassen wenigstens eines Reifenbetriebsparameters eines Reifens, wenn das Reifenmodul in dem Reifen angeordnet ist, und zum Erzeugen und drahtlosen Senden von Datensignalen, insbesondere in Abhängigkeit von einem Ergebnis der Erfassung des wenigstens einen Reifenbetriebsparameters, und
• - ein Modulgehäuse, in dem die Modulelektronik untergebracht ist.

Such electronic tire modules are known in various designs from the prior art and have:

• a module electronics for detecting at least one tire operating parameter of a tire when the tire module is arranged in the tire and for generating and wirelessly transmitting data signals, in particular depending on a result of the detection of the at least one tire operating parameter, and
• - A module housing in which the module electronics is housed.

In the case of known tire modules, the module electronics are often designed at least for detecting a tire pressure of the relevant tire and have a pressure sensor for this purpose.

In addition, the to be detected at least one tire operating parameters z. B. also include a tire temperature and / or acceleration at the placement of the tire module within the tire, for which the tire module is accordingly equipped with a temperature sensor and / or an acceleration sensor.

The data signals are usually transmitted with a radio transmitter of the module electronics to a radio receiver of the vehicle.

Since a tire module is usually equipped with an electric battery for the electrical supply of the module electronics and thereby a long battery life (eg, approximately corresponding to the typical life of a tire) is sought, the envisaged detection can not be continuous and can radio data signals only in certain temporal Spaces of typically at least a few seconds are sent to ensure a sufficiently long life of the electric battery.

If the tire module or its module electronics is equipped with a pressure sensor for measuring the tire pressure, a tire pressure monitoring system thus formed can thus advantageously z. B. warn a driver of the vehicle in question, as soon as a gradually decreasing tire pressure falls below a predetermined tire pressure threshold.

However, the known tire pressure monitoring systems are not suitable due to the relatively large time intervals between the tire pressure measurements and corresponding data signal emissions, a "sudden loss of tire pressure" z. B. as a result of sudden damage to the tire (eg., Due to age or, for example, after driving over a sharp-edged or pointed object) to capture promptly.

In the worst case, in known tire pressure monitoring systems, a sudden tire pressure loss indicating data signal could be generated only after a period of time and thus sent to a vehicle-side receiver of the system, which corresponds to the time interval of the data signal emissions. For a warning of the driver or other use of this data signal, this would usually be too late.

It is an object of the present invention to eliminate the above-described problem and in particular to improve an electronic tire module of the type mentioned so that a thus implemented tire monitoring system can detect a sudden loss of tire pressure in a timely manner.

This object is achieved by an electronic tire module according to claim 1. The dependent claims relate to advantageous developments and refinements of the invention.

In the tire module according to the invention, a module cavity is further formed in the module housing, which is connected via a leading out of the module housing air flow passage with an environment of the tire module. In addition, the tire module has a sensor device accommodated in the module housing, which is designed to detect a predetermined extent exceeding air flow from the module cavity via the air flow passage out into the environment of the tire module and a corresponding flow detection signal to the module electronics for detecting a sudden loss of tire pressure Tire spend.

The operation is as follows: A sudden loss of tire pressure leads to a rapid and considerable drop in tire pressure, ie the pressure in the vicinity of the tire module (arranged in the tire). As a result, air flows out of the module cavity via the air flow passage into the environment of the tire module, depending on the volume of the module cavity and Depending on the flow resistance of the air flow passage, the pressure in the module cavity adjusts to the pressure in the vicinity of the tire module (tire pressure) within a short "adjustment period".

The basic idea of the invention is to detect as a tire operating parameter, whether exclusive or in addition, a sudden loss of tire pressure based on the existence of said air flow during the adjustment period.

According to the invention, this is realized by the sensor device accommodated in the module housing, which outputs a corresponding flow detection signal to the module electronics so that the module electronics can detect the sudden loss of tire pressure based on the flow detection signal and correspondingly take into account the generation and wireless transmission of the data signals.

As described below, based on this detection principle, embodiments of the sensor device with minimal energy consumption are advantageous.

In one embodiment, it is provided that the sensor device has a flow sensor arranged in the air flow passage.

In this embodiment, the air flow is effectively detected directly (as such), according to a first embodiment may be provided that the flow sensor comprises a turbine driven by the air flow and signal generating means for generating the flow detection signal due to rotation of the turbine, wherein the signal generating means z. B. may have a rotationally driven by the rotation of the turbine electric generator.

According to a second embodiment variant of the embodiment with a flow sensor, it is provided that the flow sensor has a flap which can be displaced and / or deformed by the air flow and signal generating means for generating the flow detection signal as a result of a displacement and / or deformation of the flap, wherein the signal generating means z. B. a piezoelectric device or z. B. a Hall probe or z. B. may have an electrical switch.

As a piezoelectric device can, for. Example, a piezoelectric material layer may be provided which forms the flap or a part of the flap, so that in the case of deformation of the flap (due to the air flow) is generated as a flow detection signal to the module electronics outputable piezo voltage.

In the case of using a Hall probe can, for. B. be provided to integrate the Hall probe as part of the flap in the flap and in a region of the air flow passage bounding wall a magnetic field generating means, in particular z. As a permanent magnet, to be arranged, such that upon a displacement and / or deformation of the flap due to the air flow, a relative arrangement of the Hall probe and the magnetic field generating means to each other changed. In this case, a Hall voltage can be detected by the module electronics as the flow detection signal. The locations of the Hall probe and magnetic field generating means may also be interchanged, i. the probe may be provided in a stationary region of the air flow passage (eg, wall thereof) and the magnetic field generating means on the flap.

An electrical switch can, for. Example, be formed with two electrical switch contacts, one of which is formed on the flap and the other in the stationary region of the air flow passage, such that at a displacement and / or deformation of the flap due to the air flow, these switches either open or (preferably) closed becomes. In this case, the generation of the flow detection signal to be detected by the module electronics is based on the detection of the switch state. In particular, it may be provided to apply a voltage to the normally open switch and to detect the occurrence of the air flow on the basis of the current flow via the (then closed) switch.

In the embodiments of the sensor device described so far, a direct detection of the air flow exceeding a predetermined extent is provided. The predetermined extent can be set within wide limits by the choice of design details of the flow sensor.

In another embodiment, an indirect detection of the air flow is realized in that the sensor device has a arranged in the region of the module housing pressure difference sensor for measuring a pressure difference between a pressure in the housing cavity and a pressure in the vicinity of the tire module.

The operating principle of this embodiment is based on the physical fact that the air flow rate through the air flow passage always in good approximation proportional to the pressure difference of the pressures on both sides of Air flow passage is. This pressure difference is therefore quantitatively representative of the extent of air flow through the air flow passage. Also in this embodiment, by appropriate choice of design details of the pressure difference sensor, the "pressure loss detection triggering" predetermined amount of air flow can be set within wide limits.

In a specific embodiment of this embodiment, it is provided that the pressure difference sensor has a membrane formed at least partially of piezoelectric material, which is loaded on one side by the pressure in the housing cavity and on the other side by the pressure in the vicinity of the tire module.

For example, the membrane may have on at least one of its flat sides a coating of piezoelectric material, so that the piezoelectric voltage generated thereon can be detected as the flow detection signal from the module electronics.

Alternatively comes z. B. into consideration, on the one hand to use an electrically conductive middle section of the membrane and on the other hand adjacent thereto stationarily arranged in the flow passage electrical conductor as contacts of an electrical switch in the manner already described above for generating the module electronics to be detected flow detection signal.

Depending on the specific configuration of the sensor device in a tire module according to the invention, it can not always be ruled out that gravitational forces and, during a rotation of the relevant vehicle tire, centrifugal forces also influence the detection process. In one embodiment, the tire module therefore has an acceleration sensor and the module electronics are designed to take into account an acceleration sensor signal supplied by the acceleration sensor in order to compensate for the aforementioned influence on the detection of the sudden loss of tire pressure (in addition, the acceleration sensor signal may for example be provided by the module electronics processed to detect a rotational speed and / or rotational position of the vehicle tire). Alternatively or additionally, especially with the use of a flap or a membrane, it may also be provided to minimize the aforementioned influence by providing an arrangement of the flap or membrane in which one plane of the flap or membrane is at least approximately one Radial level of the vehicle tire represents.

The tire module according to the invention (or its module electronics) is preferably designed such that a detection of a sudden loss of tire pressure immediately sends a data signal indicating this detection.

In accordance with another aspect of the invention, there is provided a tire monitoring system for a vehicle tire-equipped vehicle, comprising one or more electronic tire modules of the type described herein and receiving means for receiving data signals transmitted by the electronic tire modules.

According to a further aspect of the invention, a vehicle is provided with a driver assistance system, for example with an ESP (Electronic Stability Program) and / or ABS (Anti-lock Braking System), and with a tire monitoring system comprising one or more electronic tire modules of the type described here, wherein the tire monitoring system is designed for this purpose is, in the case of detecting a sudden loss of tire pressure to output this detection indicating data signal to the driving assistance system.

In many applications, the use of the invention allows a considerable improvement in the functionality of driver assistance systems, in particular an ESP. In conventional vehicles, sudden tire pressure loss on a tire typically results in immediate shutdown of the ESP, because proper operation of the ESP requires proper detection of individual wheel rotational speeds of the individual wheels, but with a drastic change in the dynamic wheel radius Tire due to the sudden pressure loss on this tire causes erroneous or implausible measurements for the Raddrehgeschwindigkeit and in this case the shutdown of the ESP is provided. The same applies to the case where such erroneous or implausible measured values of the wheel rotational speeds are caused due to a defect in the sensor system used for this purpose (for example, rotational angle sensors arranged in the vehicle on each vehicle wheel). In known vehicles, the ESP can not distinguish between the cases of a tire pressure loss and a defect in the sensor for measuring rotational speed.

Using the invention, however, such distinctness is advantageously made possible, since in the case of a sudden loss of tire pressure, a data signal indicating this can be sent immediately from the relevant module electronics to a receiver arranged in the vehicle and immediately provided to the ESP on the vehicle side.

Based on this timely information of the ESP, especially if the data signal sent from the respective electronic tire module also contains localization information, ie the information on which tire of the vehicle the sudden tire pressure loss has occurred, the ESP can advantageously enter a corresponding special ESP operating mode change, in which for the stabilization of the driving dynamics of the vehicle, the circumstance of a more or less "flat tire" is taken into account in a suitable manner. For example, in this mode of operation, special characteristics of a flat tire (as opposed to a properly air-filled tire) may be taken into account or, for example, as follows: B. the lowest possible mechanical stress of the flat tire can be provided.

Thus, the invention advantageously makes it possible to maintain a functionality of the ESP or of another driver assistance system even after a sudden loss of tire pressure.

In particular with the embodiments of the sensor module provided according to the invention in the tire module, a timely detection of this pressure loss can be realized with reasonable (low) power consumption in order to advantageously ensure a high battery life.

• 1 eine Seitenansicht eines Fahrzeugreifens mit einem darin angeordneten elektronischen Reifenmodul, sowie ein Blockschaltbild eines Teils einer Fahrzeugelektronik zum Empfangen und Verarbeiten von Datensignalen des Reifenmoduls,
• 2 ein Blockschaltbild des im Ausführungsbeispiel von 1 verwendeten Reifenmoduls,
• 3 eine Seitenansicht des Reifenmoduls von 1 gemäß einer ersten konstruktiven Ausführungsvariante,
• 4 eine teilweise Seitenansicht des Reifenmoduls gemäß einer zweiten konstruktiven Ausführungsvariante, und
• 5 eine teilweise Seitenansicht des Reifenmoduls gemäß einer dritten konstruktiven Ausführungsvariante.

The invention will be further described by means of embodiments with reference to the accompanying drawings. They each represent schematically:

• 1 a side view of a vehicle tire with an arranged therein electronic tire module, and a block diagram of a part of a vehicle electronics for receiving and processing of data signals of the tire module,
• 2 a block diagram of the embodiment of 1 used tire module,
• 3 a side view of the tire module of 1 according to a first constructional variant,
• 4 a partial side view of the tire module according to a second constructive embodiment, and
• 5 a partial side view of the tire module according to a third constructive variant.

1 shows a vehicle wheel 1 with a rim 2 and a tire mounted on the rim 3 , The arrow 4 symbolizes a rotation of the vehicle wheel 1 while driving one with the vehicle wheel 1 equipped vehicle. Depending on the type of vehicle, a corresponding number of vehicle wheels on the example of 1 be provided kind shown.

In the tire 3 is an electronic tire module 12 arranged in the example shown on the inside of a tire tread of the tire 3 is glued on. Alternatively, a tire module z. B. also be locked in a holder, which in turn is glued in the tire.

The electronic tire module 12 In the example shown, a TPMS ("tire pressure monitoring system") sensor module, ie designed to, during the drive of the vehicle from time to time radio data signals D to a radio receiver arranged in the vehicle 40 to send.

The from the tire module 12 transmitted radio signals D each contain an identification (eg identification code) of the relevant tire module 12 and information about multiple tire operating parameters, such as, in particular, a tire pressure of the tire 3 and a rotational speed of the tire 3 ,

The of the in 1 shown tire module 12 and yet other tire modules in data signals (not shown) of further tires of the vehicle D be from the radio receiver 40 of the vehicle decoded and in the illustrated example via a digital data bus system 42 (eg CAN bus, LIN bus or the like) to a central control device 44 of the vehicle forwarded for evaluation.

The control device 44 in particular has a program-controlled computer unit 46 and an associated storage unit 48 for storing the operation of the computer unit 46 controlling program and storing further data.

2 shows in a block diagram the structure of the electronic tire module 12 ,

The tire module 12 has a pressure sensor 14 which is operated from time to time and then a representative of the tire pressure sensor signal p supplies.

Furthermore, the tire module 12 an acceleration sensor 16 which is operated from time to time and then one for acceleration at the location of the tire module 12 representative sensor signal "a" provides. By evaluating the signal "a" over a few revolutions of the vehicle wheel 1 in particular z. B. determine a wheel speed.

Furthermore, the tire module 12 a sensor device 18 which, in the case of a "sudden loss of tire pressure", delivers a "flow detection signal" f "in the manner explained below.

The detection signals p . a and f become a program-controlled computer unit 20 entered. The computer unit 20 is with an associated storage unit 22 connected, in which a the operation of the computer unit 20 controlling program and other data (eg identification of the tire module, wheel or tire information data, etc.) can be stored.

The computer unit 20 generates from time to time data signals by means of a radio transmitter 24 of the tire module 12 in the form of the radio data signals D to the vehicle (radio receiver 40 ).

Because in terms of a desired life of the battery-powered tire module 12 in particular the pressure sensor 14 can not be operated continuously, the specific sensor device is for detecting a tire operating parameter "sudden tire pressure loss" 18 intended.

3 illustrates the constructive implementation of the electronic tire module 12 , comprising a module electronics 30 that with a battery 32 is operated.

The module electronics 30 includes in particular the with regard to 2 already described components 14 . 16 . 20 . 22 and 24 and thus serves to detect in particular the tire operating parameters "tire pressure" and "acceleration", and to generate and wirelessly transmit the data signals D depending on a result of these observations.

The tire module 12 also has a module housing 34 on, in which the module electronics 30 is accommodated and in the further a module cavity 36 is formed, which via one of the module housing 34 outgoing airflow passage 38 with an environment of the tire module 12 connected is.

In the 2 in summary with the reference number 18 designated sensor device is in the structural design according to 3 formed of three components, namely a sensor part 18-1 , here a turbine driven by air flow, a line arrangement 18-2 and an electronic detection part 18-3 the module electronics 30 by means of which from the turbine 18-1 generated flow detection signal "f" after transmission via the line arrangement 18-2 Will be received.

The in the module housing 34 accommodated sensor device 18-1 . 18-2 . 18-3 is designed to have a predetermined air flow exceeding a predetermined extent (see arrow in FIG 3 ) from the module cavity 36 out into the environment of the tire module 12 to detect and the flow detection signal "f" to the module electronics 30 for detecting a "sudden loss of tire pressure" of the tire in question 3 issue.

In the example shown, the turbine represents 18-1 in conjunction with an electric generator (not shown) in the air flow passage 38 arranged flow sensor. The flow sensor has the drivable by the air flow turbine 18-1 and as signal generating means for generating the flow detection signal "f" due to rotation of the turbine 18-1 the electric generator, due to the rotation of the turbine 18-1 is driven.

So if a sudden loss of tire pressure occurs, this leads to a short-term rotation of the turbine 18-1 , As a result, the flow detection signal (voltage) "f" generated by the electric generator becomes the line arrangement 18-2 to the detection part 18-3 issued, whereupon using the computer unit 20 and the radio transmitter 24 immediately a radio data signal D is sent to the information about the occurrence of the tire pressure loss (together with the identification of the tire module 12 ) to the vehicle.

Advantageously thus receives one of the tire module 12 (and other such tire modules) and the vehicle-mounted components 40 . 42 . 44 formed tire monitoring system 10 ( 1 ) very promptly the information about the detection of sudden tire pressure loss, so that z. B. a warning to the driver of the vehicle can be issued immediately.

The "sudden tire pressure loss" may be defined in the context of the invention, in particular with regard to a certain minimum time pressure loss rate, z. B. at least 0.1 bar / s or z. B. at least 0.5 bar / s.

Based on such a definition chosen in the specific application, the volume of the module cavity and the flow resistance of the air flow passage can be chosen in particular such that the "adjustment period" within which the pressure in the cavity is equal to the pressure in the vicinity of the tire module ( Tire pressure), z. B. is in the range of 0.05 to 1 s. During this period, a pulse-like outflow of air out of the module cavity occurs, the extent of which (eg averaged over this period) Mass flow or volumetric flow rate) then represents that amount of air flow which the sensor device should detect as a "sudden pressure loss".

In the case of a vehicle equipped with a driver assistance system, it is particularly preferred that the detection of the sudden tire pressure loss by the control device 44 is forwarded to the driver assistance system. The driver assistance system can thus advantageously take account of the circumstance of a "flat tire" when carrying out its control tasks.

In the following description of further embodiments, the same reference numerals are used for equivalent components, each supplemented by a small letter to distinguish the embodiment. In this case, essentially only the differences to the or the already described embodiments will be discussed and in the remainder hereby expressly made to the description of previous embodiments.

4 illustrates a (in 4 partially illustrated) embodiment variant of an electronic tire module 12a , which is opposite the tire module 12 from 3 only with regard to the design of the air flow detecting sensor part 18a-1 is modified.

This sensor part 18a-1 is in the example of 4 formed by a flexible and thus deformable by the air flow flap, wherein a piezoelectric coating of the flap 18a-1 in the case of deformation of the flap, a corresponding flow detection signal (piezo voltage) "f" supplies, which via a connected to the piezoelectric coating line arrangement 18a-2 is forwarded.

5 illustrates a (in 5 partially shown) further embodiment variant of a tire module 12b in which one of a module housing 34b outgoing airflow passage 38b However, a sensor device is provided for an indirect detection of an air flow over this air flow passage 38b is trained.

The sensor device has a in the region of the module housing 34b arranged sensor part 18b-1 acting as a pressure difference sensor for measuring a pressure difference between a pressure in the housing cavity 36b and a pressure around the tire module 12b is trained.

The pressure difference sensor has a membrane formed of piezoelectric material, which on one side (in 5 below) by the pressure in the housing cavity 36b and on the other side (in 5 above) is stressed by the pressure in the environment.

As in the case of air outflow through the air flow passage 38b a corresponding pressure difference exists between the two sides of the membrane (which drives the air flow), a deflection of the membrane represents a measure of the extent of the air flow through the air flow passage 38b wherein a corresponding flow detection signal "f" as a piezoelectric voltage signal via a line arrangement 18b-2 is forwarded.

LIST OF REFERENCE NUMBERS

1

vehicle

2

rim

3

tires

4

wheel rotation

10

Tire monitoring system

12

electronic tire module

14

pressure sensor

p

Pressure sensor signal

16

accelerometer

a

Acceleration sensor signal

18

sensor device

f

Flow detection signal

20

computer unit

22

storage unit

24

radio transmitter

D

Radio data signal

30

module electronics

32

battery

34

module housing

36

Modulkavität

38

Air flow passage

40

radio receiver

42

data bus system

44

control device

46

computer unit

48

storage unit

Claims (12)

An electronic tire module (12) for a tire monitoring system (10) of a vehicle, the tire module (12) comprising: module electronics (30) for detecting at least one tire operating parameter of a tire (3) when the tire module (12) in the tire (3 ), and for generating and wirelessly transmitting data signals (D), - a module housing (34), in which the module electronics (30) is housed, characterized in that in the module housing (34) further formed a Modulkavität (36) which is connected to an environment of the tire module (12) via an air flow passage (38) leading out of the module housing (34), and in that the tire module (12) further comprises a sensor device (18) accommodated in the module housing (34) adapted to detect a predetermined amount exceeding air flow from the module cavity (36) via the air flow passage (38) out in the vicinity of the tire module (12) and output a corresponding flow detection signal (f) to the module electronics (30) to detect a sudden loss of tire pressure (3). Electronic tire module (12) according to Claim 1 wherein the sensor device (18) has a flow sensor arranged in the air flow passage (38). Electronic tire module (12) according to Claim 2 wherein the flow sensor comprises a turbine (18-1) drivable by the airflow and signal generating means for generating the flow sensing signal (f) due to rotation of the turbine (18-1). Electronic tire module (12) according to Claim 3 wherein the signal generating means comprises an electric generator rotatably driven by the rotation of the turbine (18-1). Electronic tire module (12) according to Claim 2 wherein the flow sensor comprises a flap (18a-1) displaceable and / or deformable by the air flow and signal generating means for generating the flow detection signal (f) due to displacement and / or deformation of the flap (18a-1). Electronic tire module (12) according to Claim 5 wherein the signal generating means comprises a piezoelectric device. Electronic tire module (12) according to Claim 3 or 5 wherein the signal generating means comprises a Hall probe. Electronic tire module (12) according to Claim 5 wherein the signal generating means comprises an electrical switch. Electronic tire module (12) according to Claim 1 in that the sensor device has a pressure difference sensor (18b-1) arranged in the region of the module housing (34) for measuring a pressure difference between a pressure in the housing cavity (36) and a pressure in the vicinity of the tire module (12). Electronic tire module (12) according to Claim 9 wherein the pressure difference sensor (18b-1) comprises a membrane formed at least partially of piezoelectric material, which is loaded on one side by the pressure in the housing cavity (36) and on the other side by the pressure in the vicinity of the tire module (12) , A tire monitoring system for a vehicle tire (3) equipped vehicle, comprising one or more electronic tire modules (12) according to any one of Claims 1 to 10 and receiving means (40) for receiving data signals (D) sent from the electronic tire modules (12). Vehicle with a driver assistance system, for example ESP and / or ABS, and with a tire monitoring system (10) having one or more electronic tire modules (12) according to one of Claims 1 to 10 wherein the tire monitoring system (10) is adapted, in the case of detecting a sudden loss of tire pressure, to output a data signal (D) indicating this detection to the driving assistance system.

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