Method of communication between a wheel unit and a central computing unit of a motor vehicle, wheel unit for implementing said method and wheel comprising such a wheel unit

Abstract

A method for communication between a wheel unit and a central processing unit of a motor vehicle, a wheel unit for implementing said method, and a wheel comprising such a wheel unit. The invention relates to a method for communication between a wheel unit and a central processing unit of a TPMS system, said wheel unit being intended to be integrated into a wheel of a motor vehicle, said method comprising the following steps for: - transmitting (step E1) a set of transmission frames containing information relating to said wheel associated with said wheel unit, - sending (step E2) an acknowledgment frame as soon as said central processing unit has received a frame from said set of transmission frames transmitted by said wheel unit. According to the invention, the method includes a step for interrupting (step E3) the transmission of a frame from said set of transmission frames transmitted by said wheel unit. Figure for the abstract: Figure 2

Description

Title of the invention: Method of communication between a wheel unit and a central computing unit of a motor vehicle, wheel unit for implementing said method and wheel comprising such a wheel unit Technical field

[0001] The present invention relates to a method of communication between a wheel unit of a tire pressure monitoring system and a central computing unit. The invention also relates to a wheel unit for implementing said communication method and a wheel comprising such a wheel unit. Prior art

[0002] For safety purposes, it is known to equip a motor vehicle with a tire pressure monitoring system, known as "TPMS", the English acronym for "Tire Pressure Monitoring System".

[0003] Such a monitoring system generally comprises a central computing unit, wheel units which each equip an associated wheel of the vehicle and a radio frequency communication device adapted to ensure communication between each wheel unit and the central computing unit.

[0004] The central computing unit comprises an electronic calculator known as “ECU” (an English acronym for “Electronic Control Unit”).

[0005] Each wheel unit comprises an electronic box comprising a set of sensors designed in particular to detect an anomaly of the wheel. These sensors may, for example, be a tire inflation pressure sensor, a temperature sensor and a wheel acceleration sensor. The electronic box also comprises, in a conventional manner, a means for measuring the angular position of the electronic box.

[0006] Each wheel unit has a battery that provides the energy needed to transmit messages.

[0007] The communication device allows an exchange of messages, or signals, between the central unit or a mobile terminal on the one hand, and each wheel unit on the other hand. The messages include in particular data representative of the operating parameters of each wheel unit and an identification code for each wheel unit.

[0008] According to a known embodiment of the prior art, the electronic boxes of each wheel unit emit low frequency signals (called “LF signals” for “Low Frequency” in English terminology) thanks to a low frequency antenna towards the vehicle's central computing unit or a mobile terminal.

[0009] In order to reduce manufacturing costs and simplify the manufacturing process, ultra-high frequency or "UHF" radio communication, for example according to the Bluetooth® standard, is also used in the field of TPMS systems.

[0010] While the operation of transmitting low frequency (LF) signals consumes little energy, this is not the case for ultra-high frequency communication according to the Bluetooth ® standard.

[0011] However, the battery of a wheel unit has a limited lifespan and is not designed to be recharged.

[0012] There is thus a recurring need in the field of TPMS system communication to limit the consumption of the battery of a wheel unit.

[0013] One of the problems encountered during the transmission of data between the electronic boxes mounted on the wheels of motor vehicles and the central unit integrated in these motor vehicles, results from the existence of areas of radiofrequency non-coverage, commonly called "shadow zones" ("black spots" in English), which consist of relative positions between the electronic boxes and the central unit for which the communications between the latter are cut or altered.

[0014] Since the position of these non-coverage zones is very difficult to predict and define, the current solutions implemented to overcome the disadvantages linked to their presence consist, overall, of multiplying the number of messages sent.

[0015] For example, in the context of the transmission by electronic boxes of signals comprising data representative of operating parameters of each wheel, the current solution consists of transmitting signals comprising several identical data frames at regular time intervals over a rotation of the wheel.

[0016] Also, in the context of the implementation of methods for locating wheels by synchronization and angular correlation, the concept of which is based on the correlation of angular information existing between the signals delivered by the electronic box and signals delivered by a wheel speed sensor mounted in the vehicle near each wheel, the solution implemented to avoid a loss of information during transmissions on shadow zones, consists of controlling the transmission, by each electronic box, of several signals, called synchronized, delivered at successive times for different angular positions of the electronic box.

[0017] Consequently, in order to statistically guarantee the performance of radiofrequency transmissions, current solutions consist of multiplying the number of messages emitted by the electronic boxes of the wheel units by playing either on a repetition of the number of frames transmitted during each broadcast, or on a distribution of broadcasts synchronized over several angles.

[0018] The multiplication of the number of messages sent by the electronic boxes significantly reduces the battery life of a wheel unit. Statement of the invention

[0019] The present invention aims to overcome the drawbacks of the prior art, and to do this relates to a method of communication between at least one wheel unit of a tire pressure monitoring system and a central computing unit of said monitoring system, said at least one wheel unit being intended to be integrated into at least one wheel of a motor vehicle and comprising: - an electronic box, comprising a set of sensors designed to detect an anomaly of said at least one wheel and a means for measuring the angular position of said electronic box, - a battery providing the energy necessary for communication between said at least one wheel unit and said central computing unit, said method comprising the following steps aimed at: - transmit, from said at least one wheel unit, a set of transmission frames containing information relating to said at least one wheel associated with said at least one wheel unit, - sending, from said central computing unit, an acknowledgment frame as soon as said central computing unit has received at least one frame from said set of transmission frames transmitted by said at least one wheel unit, said method being remarkable in that it comprises, following said step aimed at sending said acknowledgment frame, a step aimed at interrupting the sending of at least one frame of said set of transmission frames transmitted by said at least one wheel unit.

[0020] Thus, by providing for interrupting the sending of frames following the step of sending an acknowledgment frame, it is avoided that the wheel units of the TPMS system continue to transmit while the central computing unit has received the expected information.

[0021] In this way, the number of exchanges between the electronic boxes of the wheel units and the central unit of the motor vehicle is limited.

[0022] By optimizing the exchanges in this way, the energy consumption of the wheel unit batteries is optimized.

[0023] This increases the battery life of such wheel units compared to the prior art, despite the use of communication by ultra-high frequency radio waves according to the Bluetooth® standard and while avoiding a communication mode with emission of low frequency (LF) signals, communication mode according to which the architecture is more expensive and more complex than that deployed to communicate according to the Bluetooth ® standard.

[0024] According to optional characteristics of the communication method according to the invention: - said interruption step is implemented as soon as said acknowledgment frame informing of the correct reception of said transmission frame has been sent during said sending step; - according to one embodiment, said transmission step is implemented by transmitting said set of transmission frames at predetermined transmission angles and the motor vehicle comprises a set of wheel speed sensors, said method comprises an additional step subsequent to said sending and prior to said interruption step aimed at qualifying, among said set of transmission frames transmitted during said transmission step, which ones have satisfactory reception power and which ones have unsatisfactory reception power; - said interruption step consists of interrupting the sending of transmission frames qualified during said qualification step as having unsatisfactory reception power; - in one embodiment, said satisfactory reception power has a range of values ​​between 0 dBm and -80 dBm, in particular between -40 dBm and -50 dBm; - in one embodiment, said unsatisfactory reception power has a range of values ​​less than -80 dBm, in particular between -90 dBm and -100 dBm; - according to one embodiment, said transmission step is implemented by transmitting said set of transmission frames on transmission channels and said method comprises an additional step subsequent to said sending and prior to said interruption step aimed at eliminating, from among said set of transmission frames transmitted during said transmission step, the ineffective transmission channels on which no acknowledgment frame was transmitted during said sending step; - said interruption step consists of interrupting the sending of transmission frames on said ineffective transmission channels eliminated during said elimination step; - in one embodiment, a pair of data is determined associating an optimum emission angle and an optimum emission channel; - said qualification step and / or said elimination step are carried out by implementing a learning phase; - according to one embodiment, said method comprises a step prior to said transmission step according to which said at least one wheel unit sends to said central computing unit a prior message indicating a transmission date and a transmission channel envisaged for the transmission of a first transmission frame of said set of transmission frames.

[0025] The invention also relates to a wheel unit of a tire pressure monitoring system, intended to be integrated into a motor vehicle wheel and comprising hardware and / or software means for implementing the method according to the invention.

[0026] The invention also relates to a motor vehicle wheel comprising at least one wheel unit of a tire pressure monitoring system, remarkable in that said wheel unit is according to the invention. Brief description of the drawings

[0027] Other characteristics, aims and advantages of the invention will appear on reading the detailed description which follows, for the understanding of which reference will be made to the appended drawings in which: [Fig.l] [Fig.l] is a schematic view of a motor vehicle according to the invention. [Fig.2] [Fig.2] details the steps of the communication method according to the invention. [Fig.3] [Fig.3] illustrates the steps of implementing the communication method according to a first embodiment. [Fig.4] [Fig.4] illustrates the steps of implementing the communication method according to a second embodiment. [Fig.5] [Fig.5] shows the steps of implementing the communication method according to an alternative embodiment. [Fig.6] [Fig.6] shows an example of the implementation of the method according to the embodiment variant of [Fig.5]. Description of the embodiments

[0028] In the remainder of the description, elements having an identical structure or similar functions are designated by the same reference.

[0029] Reference is made to [Fig.l] illustrating a motor vehicle 1 which is equipped with a tire pressure monitoring system, known under the name “TPMS”, the English acronym for “Tire Pressure Monitoring System”.

[0030] The TPMS system comprises a central calculation unit 3 comprising an electronic calculator known as “ECU” (an English acronym for “Electronic Control Unit”) and four wheel units 5a, 5b, 5c, 5d which are each mounted on an associated wheel 7a, 7b, 7c, 7d.

[0031] Each wheel unit 5a, 5b, 5c, 5d comprises a battery which provides the energy necessary for communication between the wheel unit 5a, 5b, 5c, 5d and the central computing unit 3.

[0032] Each wheel unit 5a, 5b, 5c, 5d further comprises an electronic box 9a, 9b, 9c, 9d, comprising a set of sensors for example secured to the rim or to the inflation valve of the wheel 7a, 7b, 7c, 7d so as to be positioned inside the tire casing, or on the internal face of the tire tread.

[0033] Each of the electronic boxes 9a, 9b, 9c, 9d is designed to detect an anomaly of the wheel 7a, 7b, 7c, 7d.

[0034] For this purpose, each of the electronic boxes 9a, 9b, 9c, 9d integrates sensors dedicated to measuring the parameters of the tires, connected to a microprocessor calculation unit linked to a transmitter 11.

[0035] Each of the electronic boxes 9a, 9b, 9c, 9d also integrates, in a conventional manner, means 13 for measuring the angular position of the electronic box 9a, 9b, 9c, 9d.

[0036] Such measuring means may advantageously consist of an accelerometer capable of providing modulated signals representative of the values ​​of gravity and therefore of the angular position of the electronic box 9a, 9b, 9c, 9d, the frequency of which, equal to the rotation frequency of the wheels 7a, 7b, 7c, 7d, also makes it possible to calculate the rotation speed of the wheels 7a, 7b, 7c, 7d.

[0037] Furthermore, the central unit 3 of the TPMS system comprises a microprocessor and a communication device 15 capable of receiving the signals emitted by the transmitters 11 of each of the four electronic boxes 9a, 9b, 9c, 9d.

[0038] For this purpose, the communication device 15 comprises a transmitter-receiver which allows a bidirectional exchange of messages or signals between the central unit 3 and each wheel unit 5a, 5b, 5c, 5d.

[0039] The messages exchanged between the central unit 3 and each wheel unit 5a, 5b, 5c, 5d include in particular data representative of operating parameters of each wheel 7a, 7b, 7c, 7d.

[0040] Communication is carried out according to a communication protocol allowing a two-way exchange of data over a short distance using ultra-high frequency or “UHF” radio waves, for example according to the Bluetooth® standard.

[0041] The motor vehicle 1 is also equipped with an active safety system such as an “ABS” anti-lock braking system or an “ESP” dynamic stability control system, comprising four wheel speed sensors 17a, 17b, 17c, 17d positioned on the motor vehicle 1, each in proximity to the wheels 7a, 7b, 7c, 7d, and adapted to provide, in the form of values ​​convertible into angular values, data representative of the orientation of the wheel 7a, 7b, 7c, 7d.

[0042] This active safety system comprises a computer 19 “ABS” or “ESP” connected to the different wheel speed sensors 17a, 17b, 17c, 17d, so as to receive the wheel speed information measured by said sensors, and programmed to anticipate regulations intended to avoid wheel lock 7a, 7b, 7c, 7d.

[0043] Usually, the wheel speed sensors 17a, 17b, 17c, 17d consist of inductive, magneto-resistive or Hall effect sensors, adapted to measure the speed of each wheel 7a, 7b, 7c, 7d on a toothed or magnetic wheel.

[0044] Such equipment makes it possible in particular, firstly, to locate the wheels 7a, 7b, 7c, 7d by a method of synchronization and angular correlation based on the correlation existing between the signals delivered by the speed sensor 13 equipping each wheel 7a, 7b, 7c, 7d and synchronized signals delivered by the wheel speed sensor 17a, 17b, 17c, 17d mounted on the motor vehicle 1 in the vicinity of each wheel 7a, 7b, 7c, 7d.

[0045] Such equipment makes it possible in particular, subsequently, to transmit signals comprising data representative of operating parameters of each wheel 7a, 7b, 7c, 7d and an identification code of the electronic box 9a, 9b, 9c, 9d mounted on said wheel.

[0046] Reference is made to [Fig.2] to illustrate the steps of the communication method according to the invention.

[0047] The communication method according to the invention aims to optimize the communication between at least one of the wheel units 5a, 5b, 5c, 5d of the TPMS system and the central computing unit 3, by limiting the energy consumption of the battery which provides the energy necessary for the communication between the wheel unit 5a, 5b, 5c, 5d and the central computing unit 3.

[0048] To do this, the communication method comprises a first step (step E1) aimed at transmitting, from at least one of the wheel units 5a, 5b, 5c, 5d, a set of transmission frames containing information relating to the wheel 7a, 7b, 7c, 7d associated with the wheel unit 5a, 5b, 5c, 5d, for example information from the TPMS system which contains the pressure and temperature values ​​of the tire associated with the wheel unit 5a, 5b, 5c, 5d.

[0049] The communication method comprises a second step (step E2) aimed at sending, from the central computing unit 3, an acknowledgment frame when the central computing unit 3 has received at least one frame from the set of transmission frames transmitted during step E1 by the wheel unit 5a, 5b, 5c, 5d.

[0050] As is known, the acknowledgment frame contains a set of information. Natively according to the Bluetooth® standard, when a transmitter transmits a frame, the receiver can indicate to the transmitter that it has received the sent frame. To do this, the transmitter transmits a frame called a "scan request". The receiver triggers the sending of a frame called a "scan response", which includes a set of additional information. Also, an acknowledgment message indicating that the sent frame has been received is then sent. The reception of an acknowledgment message can, in a known manner, trigger the triggering of a set of steps, which are not part of the invention.

[0051] According to the invention, the communication method comprises a step E3 aimed at interrupting, following step E2 aimed at sending the acknowledgment frame, the sending of at least one frame from the set of transmission frames sent during step E1 by the wheel unit 5a, 5b, 5c, 5d.

[0052] Thus, by providing for interrupting the sending of a frame from the set of transmission frames sent during step E1 by the wheel unit 5a, 5b, 5c, 5d following the sending of an acknowledgment frame, the number of transmissions of frames sent is limited while an acknowledgment frame informing of the correct reception of the transmission frame has been sent.

[0053] The number of messages sent by the electronic boxes of the TPMS system is therefore reduced, which makes it possible to significantly increase the battery life of the wheel unit 5a, 5b, 5c, 5d.

[0054] Reference is made to [Fig.3] to detail a first embodiment of the communication method according to the invention.

[0055] The communication method according to the invention can be implemented in order to interrupt the sending of transmission frames as soon as an acknowledgment frame is sent by the central computing unit 3.

[0056] To do this, step E3 aimed at interrupting the sending of a frame from the set of transmission frames sent during step E1 by the wheel unit 5a, 5b, 5c, 5d following the sending of an acknowledgment frame is implemented as soon as an acknowledgment frame informing of the correct reception of the transmission frame has been sent during step E2.

[0057] Thus, when the motor vehicle is in a so-called “regular” driving mode, the electronic unit 9a, 9b, 9c, 9d of one of the wheel units 5a, 5b, 5c, 5d transmits a set of transmission frames containing information relating to the wheel 7a, 7b, 7c, 7d associated with the wheel unit 5a, 5b, 5c, 5d (step E1 of the communication method according to the invention).

[0058] The transmission frames are for example transmitted at a predetermined time frequency, for example every 16 seconds or every 32 seconds or every 64 seconds.

[0059] More particularly, the algorithm implementing the communication method is configured to transmit these frames at a predetermined time frequency and several times during a rotation of the wheel 7a, 7b, 7c, 7d, with the aim of increasing the probability of reception by the central calculation unit 3 of the frames transmitted by the wheel unit 5a, 5b, 5c, 5d.

[0060] For example, the algorithm implementing the communication method is configured to transmit transmission frames at equidistant angles in the wheel revolution, in order to limit the risk of non-reception by the central processing unit 3. For example, the transmission frames are transmitted three times per wheel revolution as long as no acknowledgment frame is transmitted by the central computing unit 3.

[0061] According to the invention, as soon as an acknowledgment frame informing of the correct reception of the transmission frame has been sent during step E2, step E3 of the communication method interrupts the sending of subsequent frames.

[0062] For example, if, during a rotation of the wheel 7a, 7b, 7c, 7d, the first transmission frame of the set of three transmission frames transmitted by the wheel unit 5a, 5b, 5c, 5d is not received by the central computing unit 3 due to the existence of a radiofrequency non-coverage zone (“black spot” in English), then no acknowledgment frame is sent.

[0063] The rotation of the wheel 7a, 7b, 7c, 7d continues. A second transmission frame of the set of three transmission frames is then transmitted by the wheel unit 5a, 5b, 5c, 5d.

[0064] If the second transmission frame is received by the central computing unit 3, an acknowledgment frame is sent, in accordance with step E2 of the communication method of the invention.

[0065] Step E3 aimed at interrupting the sending of a frame from the set of transmission frames transmitted during step E1 by the wheel unit 5a, 5b, 5c, 5d is then initiated. The rotation of the wheel 7a, 7b, 7c, 7d continues and, in accordance with step E3 of the communication method, no further transmission frames are transmitted on the continued rotation of the wheel 7a, 7b, 7c, 7d.

[0066] Thus, in the example which has just been stated, the third transmission frame initially planned by the algorithm for implementing the method for the transmission frequency considered is not sent.

[0067] This avoids sending frames as soon as the sent frame is actually received, which very advantageously makes it possible to limit the energy consumption of the batteries of the wheel units 5a, 5b, 5c, 5d.

[0068] The reception of the acknowledgment message is thus used to deduce that the central computing unit 3 has indeed received the information transmitted by the wheel unit 5a, 5b, 5c, 5d and to command the interruption of the transmission of transmission frames by the wheel unit 5a, 5b, 5c, 5d.

[0069] Reference is made to [Fig.4] to detail a second embodiment of the communication method according to the invention.

[0070] In this embodiment, the communication method according to the invention is implemented within the framework of a rolling mode called “location mode”, used for the purposes of locating the wheels and associating the corresponding wheel units.

[0071] This functionality is typically used to detect a problem on one of the wheels of the motor vehicle and to identify which of these wheels has this anomaly.

[0072] For example, this functionality makes it possible to detect a loss of pressure due to a slow puncture and to identify which wheel is subject to this loss of pressure.

[0073] To do this, a known method consists of correlating angular information between the signals delivered by the electronic boxes 9a, 9b, 9c, 9d of the wheel units 5a, 5b, 5c, 5d and the signals delivered by the wheel speed sensors 17a, 17b, 17c, 17d.

[0074] This correlation method can be implemented using a function called “LSE”, an English acronym for “localization synchronized emission”.

[0075] This function is shared between the wheel units 5a, 5b, 5c, 5d and the central computing unit 3 of the motor vehicle 1.

[0076] In order to accomplish this function, each wheel unit 5a, 5b, 5c, 5d is configured to transmit a first transmission frame at a known angle of rotation of the wheel 7a, 7b, 7c, 7d, for example at 0°.

[0077] The other frames are for example emitted at equidistant angles during the wheel rotation. For example, four frames are emitted for one wheel rotation. Thus, the four frames are respectively emitted when the wheel rotation is 0°, then 90°, then 180°, then 270°.

[0078] For each of the wheels 7a, 7b, 7c, 7d of the motor vehicle 1, the central computing unit 3 compares the emission angles of the wheel units 5a, 5b, 5c, 5d which are known and fixed, with the reception angles of the wheel speed sensors 17a, 17b, 17c, 17d.

[0079] On the basis of this information, a table is constructed and the central computing unit 3 concludes that there is a pairing between one of the wheel units 5a, 5b, 5c, 5d and one of the wheel speed sensors 17a, 17b, 17c, 17d when, for a given wheel unit 5a, 5b, 5c, 5d, the information transmitted by the transmission frame for a known transmission angle is always received at the same angle according to one of the wheel speed sensors 17a, 17b, 17c, 17d.

[0080] On the other hand, the central computing unit 3 concludes that there is no pairing between one of the wheel units 5a, 5b, 5c, 5d and one of the wheel speed sensors 17a, 17b, 17c, 17d when, for a given wheel unit 5a, 5b, 5c, 5d, the information transmitted by the transmission frame for a known transmission angle is not always received at the same reception angle according to the wheel speed sensors 17a, 17b, 17c, 17d. The central computing unit 3 then understands that the wheel speed sensor 17a, 17b, 17c, 17d does not correspond to this wheel unit 5a, 5b, 5c, 5d.

[0081] In this embodiment, step E1 of the communication method is implemented operates by emitting, for each of the wheels 7a, 7b, 7c, 7d of the motor vehicle 1, emission frames at predetermined wheel rotation emission angles.

[0082] In accordance with step E2 of the communication method, an acknowledgment frame is sent when the central computing unit 3 has received at least one of the frames sent during step E1.

[0083] In this embodiment, the communication method comprises an additional step E21, subsequent to step E2 of sending an acknowledgment frame and prior to step E3 of interrupting the sending of a frame from the set of transmission frames.

[0084] The additional step E21 aims to qualify, among the transmission frames addressed during step E1 and for which an acknowledgment frame has been sent, which ones have a satisfactory reception power and which ones have an unsatisfactory reception power.

[0085] The information relating to the reception power can for example be measured by the wheel unit 5a, 5b, 5c, 5d of the TPMS system receiving the “scan request” frame.

[0086] Thus, the information relating to the reception power is contained in the additional information addressed by the central computing unit 3 when said central computing unit 3 transmits an acknowledgment frame.

[0087] For example, in the context of the present invention, a reception power between 0 dBm and -80 dBm is considered satisfactory. More specifically, a reception power between -40 dBm and -50 dBm is considered satisfactory.

[0088] Conversely, in the context of the present invention, a reception power of less than -80 dBm is considered to be unsatisfactory. More specifically, a reception power of between -90 dBm and -100 dBm is considered to be unsatisfactory.

[0089] Step E3 of the communication method, aimed at interrupting the sending of a frame from the set of transmission frames sent during step E1 by the wheel unit 5a, 5b, 5c, 5d following the sending of an acknowledgment frame, consists in this embodiment of interrupting the sending of transmission frames which have been qualified during step E21 as having an unsatisfactory reception power.

[0090] For the exemplary embodiment given above, the communication method operates as follows.

[0091] The wheel units 5a, 5b, 5c, 5d transmit (step El) transmission frames when the rotation angle of the corresponding wheels 7a, 7b, 7c, 7d is equal to 0°, then 90°, then 180°, then 270°.

[0092] An acknowledgment frame is sent (step E2) for the transmission frames received by the central computing unit 3.

[0093] For each of the transmission frames having been the subject of the sending of acknowledgment frames, we qualify (step E21) which have a satisfactory reception power and which have an unsatisfactory reception power.

[0094] The sending of transmission frames which were qualified during step E21 as having unsatisfactory reception power is interrupted (step E3).

[0095] In one embodiment of the invention, step E21 can be executed by implementing a learning phase.

[0096] The learning phase can be implemented over a predetermined duration which can correspond to a predetermined number of wheel revolutions 7a, 7b, 7c, 7d.

[0097] In one embodiment, the learning phase is implemented over 5, 10 or 15 wheel revolutions 7a, 7b, 7c, 7d.

[0098] In one embodiment, the learning phase can be initiated each time the motor vehicle 1 is driven or after a certain number of predetermined drives.

[0099] During the implementation of the learning phase, the communication method executes step E1 of sending transmission frames, step E2 of sending acknowledgment frames and step E21 of qualifying the reception powers throughout the duration of the learning phase, without executing step E3 of interruption.

[0100] Reference is made to [Fig.5] to detail an alternative embodiment of the communication method according to the invention.

[0101] According to the current Bluetooth® standard, each transmission frame comprises three transmission channels CH37, CH38, CH39, transmitting respectively at the frequencies 2402 MHz, 2426 MHz and 2480 MHz.

[0102] The step E1 of sending transmission frames is executed periodically on several transmission frames which follow one another in time.

[0103] In this embodiment, step E1 of the communication method is implemented by transmitting, for each of the wheels 7a, 7b, 7c, 7d of the motor vehicle 1, transmission frames on each of the transmission channels CH37, CH38, CH39 of a transmission frame.

[0104] In accordance with step E2 of the communication method, an acknowledgment frame is sent when the central computing unit 3 has received at least one of the transmission frames transmitted during step EL

[0105] This embodiment further comprises an additional step E22 of eliminating transmission channels considered to be “ineffective” transmission channels.

[0106] The additional step E22 is subsequent to the step E2 of sending an acknowledgment frame and prior to the step E3 of interrupting the sending of a frame from the set of transmission frames.

[0107] The additional step E22 aims to eliminate, among the addressed transmission frames during step E1 and on the basis of step E2 of sending acknowledgment frames, which are the transmission channels among the channels CH37, CH38, CH39 for which no acknowledgment frame was sent during step E2.

[0108] Thus, step E3 of the communication method, aimed at interrupting the sending of a frame from the set of transmission frames sent during step E1 by the wheel unit 5a, 5b, 5c, 5d following the sending of an acknowledgment frame, consists in this embodiment of interrupting the sending of transmission frames on the channels which were eliminated during step E22.

[0109] Reference is made to [Fig.6] which illustrates an example of an embodiment of the method according to the invention according to the embodiment variant of [Fig.5].

[0110] In [Fig.6], two successive transmission frames Ti and T2 are addressed by the wheel unit 5a, 5b, 5c, 5d.

[0111] The step E1 of sending transmission frames is executed on a first transmission frame Ti and on a second transmission frame T2, temporally subsequent to the transmission frame Ti.

[0112] When the channels CH37, CH38, CH39 of the transmission frame Ti have finished transmitting, the central computing unit 3 sends an acknowledgment frame for each transmission frame actually received (step E2).

[0113] In the example illustrated in [Fig.6], it is considered that the central computing unit 3 has sent acknowledgment frames for the transmission frames sent on the channels CH37 and CH39.

[0114] Step E22 of eliminating transmission channels considered to be “ineffective” channels therefore eliminates here the channel CH38, for which no acknowledgment frame was sent by the central computing unit 3 during step E2.

[0115] When the elimination step E22 has eliminated the channel CH38 considered to be an ineffective channel, the step E3 interrupts the sending of frames on the channel CH38.

[0116] Thus, for frame T2, transmission frames are transmitted only on channels CH37 and CH39.

[0117] The interruption of sending of transmission frames eliminated during step E22 can be applied over a predetermined duration which can for example correspond to a predetermined number of wheel revolutions.

[0118] The variant embodiment of the communication method which has just been described with reference to [Fig.5] and 6 applies equally well to the first embodiment described with reference to [Fig.3], as to the second embodiment described with reference to [Fig.4],

[0119] When the variant embodiment of the communication method applies to the second embodiment described with reference to [Fig.4], a pair of data associating an angle is determined by implementing steps E21 and E22 optimum transmission to an optimum transmission channel, allowing the transmission of transmission frames to be optimized both in terms of the transmission angle and the transmission channel.

[0120] Step E21 and step E22 can be implemented simultaneously or successively relative to each other.

[0121] In one embodiment of the invention, step E22 can be executed by implementing a learning phase which, as for step E21 described with reference to the previous embodiment, can be implemented over a predetermined duration which can correspond to a predetermined number of wheel revolutions 7a, 7b, 7c, 7d.

[0122] In one embodiment, the learning phase is implemented over 5, 10 or 15 wheel revolutions 7a, 7b, 7c, 7d.

[0123] In one embodiment, the learning phase can be initiated each time the motor vehicle 1 is driven or after a certain number of predetermined drives.

[0124] According to an alternative embodiment of the communication method common to all the embodiments which have just been described, the communication method comprises a step E0, prior to the step E1 of transmission of transmission frames, according to which the wheel unit 5a, 5b, 5c, 5d sends to the central calculation unit 3 a prior message indicating the transmission date and the transmission channel envisaged for the transmission of the first transmission frame of the set of transmission frames.

[0125] The wheel unit 5a, 5b, 5c, 5d comprises hardware and / or software means for implementing the method which is the subject of the invention. The software means may in particular comprise a computer program code means, comprising in particular the algorithm detailed above, suitable for carrying out the steps of the method according to the invention.

[0126] The method according to the invention has been described with reference to a communication between the wheel units 5a, 5b, 5c, 5d of the TPMS system on the one hand, and the central computing unit 3 on the other hand.

[0127] However, the method according to the invention also applies to establishing communication between the wheel units on the one hand and a mobile terminal on the other hand.

[0128] As goes without saying, the present invention is not limited to the sole embodiments of this communication method, of this wheel unit for implementing said method and of the wheel comprising such a wheel unit, described above solely as illustrative examples, but on the contrary it embraces all the variants involving the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

Claims

Claims

1. Method of communication between at least one wheel unit (5a, 5b, 5c, 5d) of a tire pressure monitoring system and a central computing unit (3) of said monitoring system, said at least one wheel unit (5a, 5b, 5c, 5d) being intended to be integrated into at least one wheel (7a, 7b, 7c, 7d) of a motor vehicle (1) and comprising: - an electronic box (9a, 9b, 9c, 9d), comprising a set of sensors designed to detect an anomaly of said at least one wheel (7a, 7b, 7c, 7d) and a means for measuring the angular position of said electronic box (9a, 9b, 9c, 9d), - a battery providing the energy necessary for communication between said at least one wheel unit (5a, 5b, 5c, 5d) and said central computing unit (3), said method comprising the following steps aimed at: - emitting (step El), from said at least one wheel unit (5a, 5b, 5c, 5d),a set of transmission frames containing information relating to said at least one wheel (7a, 7b, 7c, 7d) associated with said at least one wheel unit (5a, 5b, 5c, 5d), - sending (step E2), from said central computing unit (3), an acknowledgment frame as soon as said central computing unit (3) has received at least one frame from said set of transmission frames transmitted by said at least one wheel unit (5a, 5b, 5c, 5d), said method being characterized in that it comprises, following said step of sending said acknowledgment frame, a step of interrupting (step E3) the sending of at least one frame from said set of transmission frames transmitted by said at least one wheel unit (5a, 5b, 5c, 5d).,

2. Communication method according to claim 1, characterized in that said interruption step (step E3) is implemented as soon as said acknowledgment frame informing of the correct reception of said transmission frame has been sent during said sending step (step E2).

3. A communication method according to claim 1, wherein said transmitting step (step E1) is implemented by transmitting said set of transmission frames at predetermined transmission angles and wherein said motor vehicle comprises a set of wheel speed sensors (17a, 17b, 17c, 17d), characterized in that it comprises an additional step (step E21) subsequent to said sending step (step E2) and prior to said interruption step (step E3) aimed at qualifying, among said set of transmission frames transmitted during said transmission step (step E1), which have satisfactory reception power and which have unsatisfactory reception power.

4. Communication method according to claim 3, characterized in that said interruption step (step E3) consists of interrupting the sending of transmission frames qualified during said qualification step (step E21) as having unsatisfactory reception power.

5. Communication method according to one of claims 3 or 4, characterized in that said satisfactory reception power has a range of values ​​between 0 dBm and -80 dBm, in particular between -40 dBm and -50 dBm.

6. Communication method according to any one of claims 3 to 5, characterized in that said unsatisfactory reception power has a range of values ​​lower than -80 dBm, in particular between -90 dBm and -100 dBm.

7. Communication method according to any one of claims 3 to 6, wherein said transmission step (step E1) is implemented by transmitting said set of transmission frames on transmission channels (CH37, CH38, CH39), characterized in that it comprises an additional step (step E22) subsequent to said sending step (step E2) and prior to said interruption step (step E3) aimed at eliminating, from among said set of transmission frames transmitted during said transmission step (step E1), the ineffective transmission channels (CH37, CH38, CH39) on which no acknowledgment frame was transmitted during said sending step (step E2).

8. Communication method according to claim 7, characterized in that said interruption step (step E3) consists of interrupting the sending of transmission frames on said ineffective transmission channels (CH37, CH38, CH39) eliminated during said elimination step (step E22).

9. Communication method according to one of claims 7 or 8, characterized in that a data pair is determined associating an optimum emission angle and an optimum emission channel (CH37, CH38, CH39).

10. Communication method according to any one of claims 3 to 9, characterized in that said qualification step (step E21) and / or said elimination step are executed by implementing a learning phase.

11. Communication method according to any one of claims 1 to 9, characterized in that it comprises a step E0, prior to said transmission step (step El), according to which said at least one wheel unit (5a, 5b, 5c, 5d) sends to said central calculation unit (3) a prior message indicating a transmission date and a transmission channel (CH37, CH38, CH39) envisaged for the transmission of a first transmission frame of said set of transmission frames.

12. Wheel unit (5a, 5b, 5c, 5d) of a tire pressure monitoring system, intended to be integrated into a wheel (7a, 7b, 7c, 7d) of a motor vehicle (1) and comprising hardware and / or software means for implementing the method according to any one of claims 1 to 11.

13. Wheel (7a, 7b, 7c, 7d) of a motor vehicle (1) comprising at least one wheel unit (5a, 5b, 5c, 5d) of a tire pressure monitoring system, characterized in that said wheel unit (5a, 5b, 5c, 5d) is according to claim 12.

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