Method for determining voltage drop value on power supply battery of sensor of tire pressure monitoring system and sensor of tire pressure monitoring system for motor vehicle

Abstract

The invention relates to a method for acquiring a voltage drop value of a power supply battery of a sensor of a tire pressure monitoring system. The sensor comprises an ultrahigh frequency two-way communication device. According to the invention, the method comprises the following steps:-acquiring (step E1) a load voltage of the battery when the sensor transmits data; calculating (step E2) the voltage drop on the basis of the load voltage; -transmitting (step E3) said voltage drop. The invention also relates to a sensor for a tire pressure monitoring system.

Description

[Technical Field]

[0001] The present invention relates to a method for obtaining a voltage drop value of a power supply battery of a sensor of a tire pressure monitoring system.

[0002] The present invention also relates to a sensor for a tire pressure monitoring system of a motor vehicle. [Background Art]

[0003] For safety purposes, it is known to equip motor vehicles with a tire pressure monitoring system for the motor vehicle.

[0004] A system with a set of sensors (referred to as a "WFC" (Wheel Fitment Component) system) performs measurements through various sensors of the motor vehicle.

[0005] These sensors can be, for example, tire inflation pressure sensors, temperature sensors, or wheel acceleration sensors.

[0006] These measurements are transmitted to a central computing unit, which includes an electronic computer called an ECU (Electronic Control Unit).

[0007] Communication between the WFC system and the ECU is performed via a radio frequency communication network including a transceiver.

[0008] The set of devices implemented (sensors of the WFC system, central unit, communication network) forms a system commonly referred to as a tire pressure monitoring system (TPMS).

[0009] Tire pressure sensors are usually powered by non-rechargeable batteries.

[0010] When manufacturing tire pressure sensors, a set of tests are performed to ensure that the manufactured parts meet given specifications in order to detect any faults in the manufacture or behavior of the sensors.

[0011] To this end, a radio frequency frame commonly referred to as "RF_DIAGNOSIS" or "RF frame" is transmitted by the WFC system in order to verify whether certain basic parameters of the wheel are correct.

[0012] The RF frame provides a set of fields to ensure the absence of errors, especially on the pressure sensor.

[0013] Among these fields, the field called "V 下降 " (for voltage drop) calculates the difference between the voltage of the unloaded battery (i.e., the voltage obtained when the sensor is stationary (e.g., when the sensor is not transmitting an RF frame)) and the voltage of the battery when the sensor is loaded (i.e., when the sensor is transmitting).

[0014] Then the obtained V下降 The field is compared with a predetermined threshold value. This threshold value varies in particular according to the transmission frequency of the pressure sensor, and as the transmission frequency of the sensor varies, the sensor consumes different transmission currents.

[0015] As is well known, pressure sensors perform unidirectional link transmissions at frequencies of 433 MHz or 315 MHz.

[0016] Therefore, depending on whether the pressure sensor transmits at a frequency of 433 MHz or 315 MHz (a difference of several tens of millivolts to several hundreds of millivolts), the threshold value adopted will be different.

[0017] To reduce manufacturing costs and simplify the method for manufacturing pressure sensors, the pressure sensors can communicate via ultra-high frequency radio waves (e.g., according to standards) in a known manner.

[0018] Then, such sensors perform two-way link transmissions at a frequency in the order of 2.4 GHz.

[0019] Currently on the market Compatible components of the standard are not specifically designed for TPMS.

[0020] Therefore, their architecture does not naturally have the possibility of measuring the battery voltage when the sensor is under load (i.e., when the sensor transmits at a frequency of 2.4 GHz).

[0021] Therefore, when the sensors of the TPMS communicate via an ultra-high frequency two-way communication protocol (such as according to standards), the voltage drop of the power supply battery of the sensor cannot be determined according to the usual methods known in the art. [Summary of the Invention]

[0022] The present invention aims to overcome the drawbacks of the prior art, and for this purpose, relates to a method for obtaining the value of the voltage drop of the power supply battery of a sensor of a tire pressure monitoring system, the sensor being designed to detect anomalies in a wheel unit of a motor vehicle and including, for example, an ultra-high frequency two-way communication device according to standards, the method notably including the following steps:

[0023] - Obtaining the load voltage of the power supply battery when the sensor transmits data;

[0024] - Calculating the voltage drop based on the obtained load voltage;

[0025] - Transmitting the calculated voltage drop.

[0026] Therefore, by means of the present invention, when the system sensor is in an ultra-high frequency two-way mode (such as according to When transmitting according to the standard, the voltage drop value of the battery powering the sensor of the tire pressure monitoring system can be obtained.

[0027] The method obtained according to the invention can be used, for example, to detect certain manufacturing faults, certain damages or certain defective behaviour of a sensor of a tire pressure monitoring system.

[0028] Furthermore, the method according to the invention is combined with a method according to Compatibility with use in sensors of tire pressure monitoring systems communicating in standard ultra-high frequency two-way mode advantageously allows detection of certain manufacturing faults, certain damages or certain defective behaviors of the sensors which would not be detectable with sensors communicating in low frequency unidirectional mode (particularly 433 MHz or 315 MHz).

[0029] According to optional features of the method according to the invention:

[0030] - performing a step of acquiring the load voltage of the power supply battery when the sensor transmits data on a first transmission frame, and performing a step of transmitting the calculated voltage drop on a second transmission frame following the first transmission frame;

[0031] - performing a step of acquiring the load voltage of said power supply battery when said sensor transmits data on a first set of transmission frequencies comprising at least one transmission channel, and performing a step of transmitting said calculated voltage drop on a second set of transmission frequencies of said sensor, said second set of transmission frequencies comprising at least one transmission channel and being different from said first set of transmission frequencies used to perform said acquiring step;

[0032] - the first set of transmission frequencies comprises three transmission channels and the second set of transmission frequencies comprises a single transmission channel;

[0033] - performing a step of acquiring the load voltage of the power supply battery when the sensor transmits data on each of the transmission channels, and the transmission power of at least one of the transmission channels of the first transmission frequency set is different from the transmission power of the other transmission channels of the first transmission frequency set;

[0034] - performing the step of acquiring the load voltage of the power supply battery when the sensor transmits data and the step of transmitting the calculated voltage drop on the same first transmission frame;

[0035] - Perform the step of obtaining the load voltage of the power supply battery when the sensor transmits data on a first set of transmission frequencies including at least one transmission channel, and perform the step of transmitting the calculated voltage drop on a second set of transmission frequencies of the sensor, the second set of transmission frequencies including at least one transmission channel and being different from the first set of transmission frequencies for performing the obtaining step;

[0036] - The first set of transmission frequencies includes a single transmission channel, and the second set of transmission frequencies includes two transmission channels following the single transmission channel of the first set of transmission frequencies;

[0037] - The first set of transmission frequencies includes two transmission channels, and the second set of transmission frequencies includes a single transmission channel following the transmission channels of the first set of transmission frequencies;

[0038] - Perform the step of calculating the voltage drop based on the obtained load voltage by measuring the no-load voltage of the power supply battery.

[0039] The present invention also relates to a sensor for a tire pressure monitoring system of a motor vehicle, and it is noted that the sensor includes hardware means and / or software means for implementing the method according to the present invention. [Description of the Drawings]

[0040] Additional features, objects, and advantages of the present invention will become apparent by reading the following detailed description, and these features, objects, and advantages can be understood with reference to the accompanying drawings, in which:

[0041] Figure 1 : Figure 1 is a schematic diagram of a motor vehicle according to the present invention;

[0042] Figure 2 : Figure 2 lists the steps of a method for obtaining the voltage drop value of the power supply battery of a sensor for a tire pressure monitoring system according to the present invention;

[0043] Figure 3 : Figure 3 schematically shows a first embodiment of the method according to the present invention;

[0044] Figure 4 : Figure 4 schematically shows a second embodiment of the method according to the present invention;

[0045] Figure 5 : Figure 5 schematically shows a third embodiment of the method according to the present invention;

[0046] Figure 6 ​​​​​​: Figure 6 Shows an alternative embodiment of a third embodiment of the method according to the present invention. [Detailed Description]

[0047] In the remainder of the specification, elements having the same structure or similar functions are denoted by the same reference numerals.

[0048] Reference Figure 1 , which shows a motor vehicle 1 according to the present invention.

[0049] The motor vehicle is equipped with a central computing unit 3, which includes, for example, an electronic computer (referred to as an "electronic control unit" (ECU)) and a memory.

[0050] The motor vehicle further includes: four wheel units 5a, 5b, 5c, 5d, each of which is mounted on an associated wheel 7a, 7b, 7c, 7d; and at least one communication device 9, which allows two-way exchange of messages or signals between the central unit 3 and each wheel unit 5a, 5b, 5c, 5d.

[0051] Each wheel unit 5a, 5b, 5c, 5d includes an electronic housing that contains a set of sensors (not shown), which are particularly designed to measure parameters such as the pressure and temperature of a tire mounted on the associated wheel, and are designed to detect anomalies in the corresponding wheel unit.

[0052] Communication with the sensors of the TPMS is carried out according to a communication protocol that allows short-range two-way data exchange using ultra-high frequency (UHF) radio waves, for example, according to standards.

[0053] Therefore, the sensors of the TPMS include ultra-high frequency two-way radio frequency communication devices according to standards.

[0054] The sensors of each wheel unit define a system called the "WFC" ("Wheel Fitment Component") system.

[0055] This set including the sensors of the WFC system, the central unit, and the communication device forms a system commonly referred to as a tire pressure monitoring system (TPMS).

[0056] The sensors of the TPMS, especially the tire pressure sensors, are usually powered by non-rechargeable supply batteries.

[0057] The supply battery can be, for example, a 3-volt lithium button battery (e.g., type CR2032).

[0058] Reference Figure 2, This figure shows the steps of a method for obtaining the voltage drop value of the power supply battery of a sensor for a tire pressure monitoring system according to the present invention.

[0059] In one embodiment of the present invention, the method according to the present invention is started when manufacturing the sensor of the TPMS in order to monitor whether the manufactured sensor meets the requirements of the specifications.

[0060] To this end, the sensor of the TPMS includes hardware means and / or software means adapted to implement the method according to the present invention.

[0061] The software means may in particular include computer program code means, in particular algorithms designed to execute the steps of the method according to the present invention.

[0062] The method according to the present invention includes a first step E1 of obtaining the load voltage V of the power supply battery of the sensor to be monitored 负载 of.

[0063] The load voltage V 负载 is the voltage of the battery when the sensor transmits data.

[0064] This data transmission occurs when the sensor transmits a radio frequency frame (e.g., a frame called "RF_DIAGNOSIS" or an "RF frame").

[0065] When transmitting the RF frame, the battery consumes a certain amount of energy and thus current. This consumption causes a voltage drop in the battery of the monitored sensor, for example, a drop of dozens of millivolts to hundreds of millivolts. Therefore, the load voltage V 负载 is thus lower than the no-load voltage V of the battery 空载 , which is observed when the sensor is stationary (i.e., when the sensor is not transmitting).

[0066] The obtaining step E1 is performed on one or more transmission channels of the sensor, as will be seen in the rest of the specification.

[0067] Based on the load voltage V 负载 thus obtained, the method of the present invention includes a second step E2, during which the voltage drop V 负载 is calculated based on the obtained load voltage V 下降 .

[0068] The following formula is used to obtain the value of the voltage drop V 下降 :

[0069] V 下降 = V 空载 - V 负载

[0070] where:

[0071] V 下降 is the voltage drop of the battery;

[0072] V 空载 is the no-load voltage of the battery;

[0073] V 负载 is the voltage of the battery with load.

[0074] According to a first alternative embodiment of the method according to the invention, for calculating the voltage drop V 下降 of the no-load voltage V 空载 of the battery is equal to the no-load voltage specified by the battery manufacturer. Therefore, the no-load voltage V 空载 of the battery is a theoretical value.

[0075] Therefore, only the measurement of the load voltage V 负载 of the battery is performed in order to infer therefrom the voltage drop V 下降 .

[0076] According to a second alternative embodiment of the method according to the invention, the no-load voltage V 下降 for calculating the voltage drop V 空载 of the battery is obtained by measuring the no-load voltage of the battery (i.e., the voltage when the sensor is stationary, for example, when the sensor does not transmit an RF frame).

[0077] For example, this measurement is performed before measuring the load voltage V 负载 of the battery.

[0078] In this case, the no-load voltage V 空载 of the battery is real and allows the wear factor of the battery to be taken into account. In fact, over time, the no-load voltage V 空载 of the battery may decrease by several tens or hundreds of millivolts compared to its original value specified by the battery manufacturer.

[0079] Therefore, by means of this second alternative embodiment, compared to the first alternative embodiment, the calculation of the voltage drop V 下降 is thus optimized.

[0080] The voltage drop V 下降 can be calculated by software or physical means known to those skilled in the art.

[0081] According to a third step E3 of the method according to the invention, the method includes a step of transmitting the voltage drop V 下降 calculated during step E2.

[0082] The transmission step E3 is implemented on one or more transmission channels of the sensor that are different from one or more transmission channels used for performing the acquisition step E1, as will be seen in the remainder of the specification.

[0083] Reference Figure 3 , which shows a first embodiment of the method according to the present invention.

[0084] In this first embodiment, the step E1 of obtaining the load voltage V is performed on the first transmission frame T1 of the sensor, and the step E3 of transmitting the calculated voltage drop V is performed on the second transmission frame T2 of the sensor that is temporally after the transmission frame T1. 负载 下降 of.

[0085] According to the current standard, each transmission frame of the sensor includes three transmission channels CH37, CH38, and CH39, which transmit at frequencies of 2402 MHz, 2426 MHz, and 2480 MHz, respectively.

[0086] For example, the step E1 of obtaining the load voltage V implemented on the first transmission frame T1 is performed on each transmission channel CH37, CH38, and CH39 of the first transmission frame T1. 负载 of.

[0087] When the channels CH37, CH38, and CH39 of the transmission frame T1 have stopped transmitting, the step E1 of obtaining the load voltage V is stopped, and the step E2 of calculating the voltage drop V based on the obtained load voltage V is started. 负载 负载 下降 of.

[0088] To perform the step E2 of calculating the voltage drop V, the no-load voltage V of the battery can be equal to the no-load voltage specified by the battery manufacturer, or the no-load voltage can be measured before measuring the load voltage V of the battery (previous step indicated by the reference numeral "EP" in 下降 空载 ). 负载 Figure 3 ).

[0089] In the case where the sensor has completed transmission on the transmission frame T1, the step E3 of transmitting the thus calculated voltage drop V is performed when transmitting the next transmission frame T2. 下降 of.

[0090] For example, the step E3 of transmitting the voltage drop V implemented on the second transmission frame T2 is performed on the transmission channel CH39 of the second transmission frame T2. 下降 of.

[0091] For example, the second transmission frame T2 on which the step E3 of transmitting the voltage drop V is implemented directly follows the first transmission frame T1. 下降

[0092] ​​​​​​In the provided embodiment, the sensor performs the step of acquiring the load voltage V 负载 The transmission channels CH37, CH38, and CH39 of the first transmission frame T1 where step E1 is located define a first transmission frequency set EF1 belonging to the first transmission frame T1.

[0093] As a variant, the first transmission frequency set EF1 can be defined by only one of the channels CH37, CH38, CH39 of the first transmission frame T1 or by two of the channels CH37, CH38, CH39 of the first transmission frame T1.

[0094] Similarly, in the provided embodiment, the sensor performs the step of transmitting the voltage drop V 下降 The transmission channel CH39 of the second transmission frame T2 where step E3 is located defines a second transmission frequency set EF2 different from the first transmission frequency set EF1 used for performing the acquisition step.

[0095] As a variant, the second transmission frequency set EF2 can be defined by another transmission channel (channel CH37 or channel CH38) of the second transmission frame T2, or can be defined by several channels CH37, CH38, CH39 of the second transmission frame T2.

[0096] In this first embodiment, the value of the voltage drop V 下降 calculated based on the data acquired during the transmission of the transmission frame N is then transmitted during the transmission of the transmission frame N + 1.

[0097] In this way, the value of the voltage drop V 下降 can be provided in the most recent transmission.

[0098] Refer to Figure 4 , which shows a second embodiment of the method according to the present invention.

[0099] In this second embodiment, several measurements are performed on the load voltage V 负载 by configuring the transmission power of the sensor on one or more of the transmission channels CH37, CH38, CH39 in the same transmission frame T1.

[0100] Thus, for example, step E1 of acquiring the load voltage V 负载 implemented on the first transmission frame T1 is performed on each of the transmission channels CH37, CH38, CH39 of the first transmission frame T1, and the transmission power can vary from one transmission channel to the next.

[0101] In Figure 4 the example shown, the power P1 of channel CH37 of frame T1 is lower than the power P2 of channel CH38, and the power P2 itself is lower than the power P3 of channel CH39.

[0102] For example, the power P1 of channel CH37 can be equal to -2 dBm, the power P2 can be equal to 0 dBm, and the power P3 can be equal to +2 dBm.

[0103] As a variant, the power P3 can be lower than the power P2, and the power P2 itself is lower than the power P1. Additionally, the power P1 can be higher than the power P3, and the power P3 itself is higher than the power P2.

[0104] For the first embodiment, on the second transmission frame T2 after the transmission frame T1 of the sensor, perform the transmission of the calculated voltage drop V based on the data obtained when transmitting on the channel of the transmission frame T1. 下降 Step E3.

[0105] In the provided embodiment, the sensor performs the transmission of the voltage drop V 下降 The transmission channel CH39 of the second transmission frame T2 where step E3 is located defines a second transmission frequency set EF2 different from the first transmission frequency set EF1 used to perform the acquisition step.

[0106] As a variant, the second transmission frequency set EF2 can be defined by another transmission channel (channel CH37 or channel CH38) of the second transmission frame T2, or can be defined by several channels CH37, CH38, CH39 of the second transmission frame T2.

[0107] By changing the transmission power, some faults in the sensor can be inferred. Notably, it is possible to detect the absence of electronic components, especially the "matching" components present between the circuit and the transmission antenna.

[0108] Reference Figure 5 , which shows a third embodiment of the method according to the present invention.

[0109] In this third embodiment, perform step E1 of acquiring the load voltage V 负载 and step of transmitting the calculated voltage drop V 下降 on the same transmission frame T1.

[0110] To this end, perform step E1 of acquiring the load voltage V 负载 on the first transmission frequency set EF1 including a single transmission channel CH37, while perform step E3 of transmitting the calculated voltage drop V 下降 on the second transmission frequency set EF2, which includes two transmission channels CH38, CH39 after the single transmission channel CH37 of the first transmission frequency set EF1.

[0111] According to Figure 6In the alternative embodiment shown, step E1 of obtaining the load voltage V is performed on a first transmission frequency set EF1 including two transmission channels CH37, CH38, while step E3 of transmitting the calculated voltage drop V is performed on a second transmission frequency set EF2, which includes a single transmission channel CH39 after the transmission channels CH37, CH38 of the first transmission frequency set EF1. 负载 Thus, according to this third embodiment, compared with the first and second embodiments, regardless of which variant is used (i.e., 下降 the variant shown or

[0112] the variant shown), the transmission time is reduced and thus the cycle time is decreased. Figure 5 In fact, it is no longer necessary to wait for the transmission of the second transmission frame T2 to transmit the calculated voltage drop V on the second transmission frequency set EF2 of the first transmission frame T1. Figure 6 That is to say, on the same transmission frame T1 as the transmission frame used to measure the load voltage V

[0113] but on a transmission frequency set different from the transmission frequency set used to measure the load voltage V 下降 the value of V is transmitted.

[0114] In an embodiment of the present invention, the method according to the present invention is started when manufacturing the sensor of the TPMS. 负载 The method according to the present invention can be used to detect certain manufacturing faults, damages or defective behaviors of the sensor. 负载 In addition, making the method according to the present invention compatible with the use in sensors of a tire pressure monitoring system that communicates in a standard ultra-high frequency two-way mode, for example, advantageously allows the detection of certain manufacturing faults, certain damages or certain defective behaviors of the sensor, which would not be possible to detect with sensors that communicate in a low-frequency one-way mode (especially 433 MHz or 315 MHz). 下降 By way of non-limiting example, the method of the present invention can be used for:

[0115] - detecting a batch of malfunctioning power supply batteries (internal resistance exceeding specifications);

[0116] - detecting batteries that have been stored for too long, for example, due to factory shutdowns, bad weather, pandemics, etc.

[0117]

[0118]

[0119]

[0120]

[0121] ​​​​​- Infer that certain finished products have been stored for too long;

[0122] - Detect the absence of electronic components, especially the "matching" components present between the circuit and the transmission antenna. Their absence causes an increase in current when transmitting frames, resulting in a voltage drop value V that exceeds the limit. 下降 ;

[0123] - Detect incorrect values of certain "matching" electronic components;

[0124] - Detect the presence of incorrect soldering on the transmission antenna or other components;

[0125] - Detect non - compliance in the transmission antenna;

[0126] - Detect unforeseen online coupling effects with metal parts, which can lead to excessive power consumption of the supply battery;

[0127] - Detect consumption failures of the chipset, which can lead to a reduced service life of the finished product or a risk of premature degradation of the supply battery.

[0128] The method according to the invention can be particularly applied to the pressure sensors of the TPMS of a motor vehicle. However, the method can be applied to all sensors of the TPMS powered by a supply battery.

[0129] Of course, the present invention is not limited to the embodiments of the method for obtaining the voltage drop value of the supply battery of the sensors of the tire pressure monitoring system and the embodiments of such sensors for the tire pressure monitoring system of a motor vehicle, which have been described above only by way of illustrative examples. On the contrary, the present invention covers any variants of the described device and their combinations (if these variants fall within the scope of the present invention) that are technically equivalent.

Claims

1. A method for obtaining the voltage drop (V 下降 ) value of a supply battery of a sensor of a tire pressure monitoring system, the sensor being designed to detect anomalies in wheel units (5a, 5b, 5c, 5d) of a motor vehicle and including a very high frequency bidirectional communication device, the method being characterized in that it comprises the following steps: - Obtain (step E1) the load voltage (V 负载 ) of the power supply battery when the sensor transmits data; - Calculate (step E2) the voltage drop (V 负载 ) based on the obtained load voltage (V 下降 ); - Transmit (step E3) the calculated voltage drop (V 下降 ).

2. The method according to claim 1, characterized in that, Perform the step (E1) of obtaining the load voltage (V 负载 ) of the power supply battery when the sensor transmits data on the first transmission frame (T1), and perform the step (E3) of transmitting the calculated voltage drop (V 下降 ) on the second transmission frame (T2) after the first transmission frame (T1).

3. The method according to claim 2, wherein: - Perform step (E1) of obtaining the load voltage (V 负载 ) of the supply battery when the sensor transmits data on a first set of transmission frequencies (EF1) including at least one transmission channel (CH37, CH38, CH39); - Perform the step (E3) of transmitting the calculated voltage drop (V 下降 ) on a second set of transmission frequencies (EF2) of the sensor, the second set of transmission frequencies including at least one transmission channel (CH37, CH38, CH39) and being different from the first set of transmission frequencies (EF1) used to perform the acquisition step (E1).

4. The method according to claim 3, wherein The first transmission frequency set (EF1) includes three transmission channels (CH37, CH38, CH39), and the second transmission frequency set (EF2) includes a single transmission channel (CH37, CH38, CH39).

5. The method according to any one of claims 3 or 4, characterized in that, Perform the step (E1) of obtaining the load voltage (V 负载 ) of the power supply battery when the sensor transmits data on each transmission channel in the transmission channels (CH37, CH38, CH39), and the transmission power (P1, P2, P3) of at least one transmission channel in the transmission channels (CH37, CH38, CH39) of the first transmission frequency set (EF1) is different from the transmission power (P1, P2, P3) of other transmission channels (CH37, CH38, CH39) of the first transmission frequency set (EF1).

6. The method according to claim 1, wherein Perform the step (E1) of obtaining the load voltage (V 负载 ) of the power supply battery when the sensor transmits data and the step (E3) of transmitting the calculated voltage drop (V 下降 ) on the same first transmission frame (T1).

7. The method according to claim 6, wherein: - Perform the step (E1) of obtaining the load voltage (V 负载 ) of the supply battery when the sensor transmits data on a first set of transmission frequencies (EF1) including at least one transmission channel (CH37, CH38, CH39); - Perform the step (E3) of transmitting the calculated voltage drop (V 下降 ) on a second transmission frequency set (EF2) of the sensor, the second transmission frequency set including at least one transmission channel (CH37, CH38, CH39) and being different from the first transmission frequency set (EF1) used to perform the acquisition step (E1).

8. The method according to claim 7, wherein The first transmission frequency set (EF1) includes a single transmission channel (CH37), and the second transmission frequency set (EF2) includes two transmission channels (CH38, CH39) after the single transmission channel (CH37) of the first transmission frequency set (EF1).

9. The method according to claim 7, wherein The first transmission frequency set (EF1) includes two transmission channels (CH37, CH38), and the second transmission frequency set (EF2) includes a single transmission channel (CH39) after the transmission channels (CH37, CH38) of the first transmission frequency set (EF1).

10. The method according to any one of claims 1 to 9, characterized in that, By measuring the no-load voltage (V 空载 ) of the power supply battery, the step (E2) of calculating the voltage drop (V 负载 ) based on the obtained load voltage (V 下降 ) is performed.

11. A sensor for a tire pressure monitoring system of a motor vehicle (1), characterized in that, The motor vehicle includes hardware means and / or software means for implementing the method according to any one of claims 1 to 10.

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