Method for optimizing the lifespan of a wheel unit

Abstract

A method for optimizing the lifespan of a wheel unit (11, 12, 13, 14) contained within a wheel (1, 2, 3, 4) of a motor vehicle (5), said wheel unit comprising a data sensor (21, 22, 23, 24) and at least one means for transmitting data (31, 32, 33, 34) from the wheel unit (11, 12, 13, 14) to a centralized control unit (6) of the motor vehicle (5), characterized in that the wheel unit (11, 12, 13, 14) is subjected to an activity strategy based on the temperature measured by the data sensor (21, 22, 23, 24) so ​​as to reduce the energy consumption of the wheel unit (11, 12, 13, 14). Abstract figure: Figure 1

Description

Title of the invention: Method for optimizing the lifespan of a wheel unit technical field

[0001] The technical sector of the present invention relates to methods for optimizing the lifespan of a wheel unit. Previous technique

[0002] Nowadays, it is known to mount a wheel unit in each wheel of a motor vehicle to control certain parameters of the wheel comprising the wheel unit. Such a wheel unit is generally referred to as a module in a tire pressure monitoring system.

[0003] The wheel unit allows, for example, the measurement of the pressure and temperature of a wheel. The wheel unit incorporates a microprocessor that allows the measured data associated with the wheel to be grouped, stored, and then transmitted regularly and periodically to a control unit embedded in the motor vehicle and located remotely from the wheel unit.

[0004] Data transmission from the wheel unit to the control unit is generally carried out by unidirectional radio frequency transmission. This allows for a comparative analysis between the wheel pressure data from each wheel unit of the vehicle and for the detection of a tire leak or puncture.

[0005] Most legislation requires that a leak or puncture be detected in less than ten minutes during vehicle operation. Therefore, the wheel unit typically transmits data to the control unit periodically every 8 or 16 seconds.

[0006] The wheeled units are equipped with a button cell battery that provides the energy required for the operations performed by the wheeled unit. Generally, the lifespan of a wheeled unit is 10 years for a typical mission profile.

[0007] More recently, short-range data signal communication systems have been used to ensure bidirectional communication between the wheel unit and the control unit. Such systems notably use UHF (Ultra High Frequency) radio waves according to a Bluetooth®-type communication standard or another UHF wave communication standard. The use of these systems requires equipping the wheel unit with an additional communication system, such as a data receiver, to enable bidirectional communication.

[0008] In particular for the wheel unit, such a communication system further comprises a microprocessor, memory units and data transmission and reception peripherals will increase the energy consumption of the wheel unit and therefore decrease its lifespan compared to a wheel unit equipped only with a unidirectional radio frequency transmission communication system.

[0009] Furthermore, short-range data signal communication systems are not particularly suitable for use in the automotive field. Indeed, the components of a wheel unit are subjected to temperatures ranging from -40°C to +125°C. However, most components of short-range data signal communication systems have a typical operating range not exceeding 105°C.

[0010] Furthermore, a well-known phenomenon in the field of microelectronics is the increase in current consumed by a component at rest in response to an increase in the component's temperature. For example, a component at rest that consumes a few hundred nanoamperes at 25°C can consume tens of microamperes at 105°C.

[0011] However, according to the typical mission profile, characterized in particular by long periods of vehicle standstill, the energy consumption level of the wheel unit at rest primarily determines its lifespan. This impact is all the more significant as the wheel unit may be subjected to relatively high temperatures for extended periods. As for energy consumption during movement phases, although these are shorter, it remains particularly high when maximum temperatures are reached.

[0012] Moreover, premature aging of batteries is also observed when they are subjected to very low or even low temperatures.

[0013] An objective of the present invention is to remedy the aforementioned disadvantages in order to optimize the energy consumption of a wheel unit so as to increase the lifespan of said wheel unit. Summary

[0014] The invention therefore relates to a method for optimizing the lifespan of a wheel unit included in a wheel of a motor vehicle, said wheel unit comprising a data sensor and at least one means for transmitting data from the wheel unit to a centralized control unit of the motor vehicle, remarkable in that the wheel unit is subjected to an activity strategy based on the temperature measured by the data sensor in order to reduce the energy consumption of the wheel unit.

[0015] According to one embodiment of the invention, the activity strategy includes increasing the periodicity of data emissions from the wheel unit to the centralized control unit.

[0016] Advantageously, the periodicity of data emissions is between 60 seconds and 600 seconds.

[0017] According to another embodiment of the invention, the activity strategy includes modifying the data transmission power.

[0018] According to another embodiment of the invention, the activity strategy includes reducing the amount of data transmitted from the wheel unit to the control unit.

[0019] According to another embodiment of the invention, when at least one data transmission means is represented by a multi-channel transmission means, the activity strategy includes reducing the number of data transmission channels.

[0020] According to another embodiment of the invention, the activity strategy is imposed when the temperature measured by the data sensor is above a first predetermined threshold or below a second predetermined threshold.

[0021] Advantageously, the first predetermined threshold is between +75°C and +120°C, preferably +90°C.

[0022] Even more advantageously, the second predetermined threshold is between -40°C and +35°C, preferably -20°C.

[0023] The invention also relates to a device for implementing the method according to any one of the preceding claims.

[0024] An advantage of the present invention lies in the optimization of the lifespan of a wheel unit comprising a wheel unit system.

[0025] Another advantage of the present invention lies in the reduction of the energy consumption of a wheel unit as a function of temperature.

[0026] Another further advantage of the present invention lies in the increased longevity of the electronic components present in the wheel unit.

[0027] Another further advantage of the present invention lies in reducing the stress on the battery of a wheel unit so as not to degrade its performance and to increase its lifespan. Brief description of the drawings

[0028] Other features, advantages and details of the invention will be better understood upon reading the supplementary description that follows in relation to the drawings in which: [fig.1] Figure 1 represents a schematic view of a motor vehicle, and [fig.2] Figure 2 represents a flowchart illustrating the different steps of the process according to the invention. Description of the implementation methods

[0029] As described previously, the invention relates to a method for optimizing the lifespan of a wheel unit.

[0030] Figure 1 shows a motor vehicle 5 that can be used to implement the process according to the invention and Figure 2 shows a flowchart illustrating the steps of the process according to one embodiment of the invention.

[0031] The motor vehicle 5 shown further comprises four wheels 1, 2, 3, 4. A wheel unit 11, 12, 13, 14 according to the invention is incorporated into a wheel 1, 2, 3, 4 of a motor vehicle 5 and allows various data associated with the wheel 1, 2, 3, 4 to be measured. The data measured are, for example, the temperature of the wheel 1, 2, 3, 4 and the tire pressure. The wheel unit 11, 12, 13, 14 includes, in particular, a battery powering the various components of the wheel unit 11, 12, 13, 14. The wheel unit 11, 12, 13, 14 also includes a data sensor 21, 22, 23, 24 for measuring the data of the wheel 1, 2, 3, 4. The wheel unit 11, 12, 13, 14 also includes at least one means for transmitting data 31, 32, 33, 34, 34 from the wheel unit 11, 12, 13, 14 to a centralized control unit 6 of the motor vehicle 5.The wheel unit 11, 12, 13, 14 also includes a microprocessor for storing and processing the data measured by the data sensor 21, 22, 23, 24.

[0032] The means of transmitting data 31, 32, 33, 34 from the wheel unit 11, 12, 13, 14 to the centralized control unit 6 of the motor vehicle 5 can be a means of transmitting short-range data signals such as, for example, UHF radio waves on a frequency base of 433 MHz or on a frequency base of 2.4 GHz.

[0033] The wheel unit 11, 12, 13, 14 according to the invention may in particular include a means for transmitting data 31, 32, 33, 34 by unidirectional or bidirectional radio frequency signals. Thus, the wheel unit 11, 12, 13, 14 may include either a means for transmitting data signals 31, 32, 33, 34 over short distances by radio frequency, for example of the UHF type, or a means for transmitting and receiving data signals 31, 32, 33, 34 over short distances by radio frequency, for example of the Bluetooth® type.

[0034] Thus, the method according to the invention consists of imposing on the wheel unit 11, 12, 13, 14 an activity strategy based on the temperature measured by the data sensor 21, 22, 23, 24. In particular, the activity strategy of the wheel unit 11, 12, 13, 14 consists of modifying the data emissions from the wheel unit 11, 12, 13, 14 to the centralized control unit 6 of the motor vehicle 5. This makes it possible to reduce the energy consumption of the wheel unit 11, 12, 13, 14, particularly during phases where the wheel unit 11, 12, 13, 14 consumes a large amount of energy. This is particularly suitable when the wheel unit 11, 12, 13, 14 includes a means for transmitting data 31, 32, 33, 34 by data signals to short-range transmission, either alone or in conjunction with a radio frequency signal transmission device 31, 32, 33, 34. Indeed, it has been proven that short-range data transmission devices 31, 32, 33, 34, such as UHF signals of the Bluetooth® standard, consume a significant amount of energy. Therefore, it is necessary to adapt the overall energy consumption of the wheel unit 11, 12, 13, 14 to optimize its lifespan.

[0035] An activity strategy for reducing the energy consumption of the wheel unit 11, 12, 13, 14 includes, for example, increasing the frequency of data transmission from the wheel unit 11, 12, 13, 14 to the centralized control unit 6 of the motor vehicle 5. Indeed, the wheel unit 11, 12, 13, 14 will be used less and will therefore consume less energy, thereby optimizing its lifespan. For example, the data transmission frequency can be between 60 and 600 seconds instead of between 8 and 16 seconds during standard use. This reduces consumption while complying with legal requirements for leak detection, for example.

[0036] The transmission strategy may also include modifying the data transmission power. For example, the data transmission power of at least one transmission means 31, 32, 33, 34 may be modified by a few decibels (dBm). At low temperatures, for example, the performance of the radio frequency stages is improved, and therefore the data transmission power can be advantageously reduced. Thus, according to one embodiment of the invention, the data transmission power is reduced by 1 dBm to 3 dBm. Indeed, by reducing the data transmission power, the energy consumption of the wheel unit 11, 12, 13, 14 is reduced. Depending on the energy-saving requirements, modifying the data transmission power may be combined with increasing the data transmission frequency.

[0037] The activity strategy may also include reducing the amount of data transmitted from the wheel unit 11, 12, 13, 14 to the centralized control unit 6 of the motor vehicle 5. Indeed, it is possible to transmit a data packet that is a function of the situation and therefore of the temperature measured by the data sensor 21, 22, 23, 24. For example, the wheel unit 11, 12, 13, 14 transmits to the centralized control unit 6 a data packet reduced by 50% compared to normal. This reduced data packet can only indicate the lower half of the identification code of the wheel unit 11, 12, 13, 14. Depending on the need for energy saving, the reduction in the amount of data transmitted from the wheel unit 11, 12, 13, 14 to the centralized control unit 6 of the motor vehicle 5 can be combined with an increase in the periodicity of data transmission and a modification of the data transmission power.

[0038] The activity strategy may also include reducing the number of data transmission channels. This embodiment of the invention is particularly suitable when at least one data transmission means 31, 32, 33, 34 is represented by a Bluetooth®-type transmission means. Typically, Bluetooth® means transmit data on three different frequency channels to enhance communication by limiting the risk of data not being received by the centralized control unit 6. Thus, it is possible to relax this regulatory constraint by using only one or even two frequency channels. This significantly reduces the energy consumption of the wheel unit 11, 12, 13, 14.Depending on the need for energy saving, the reduction in the number of data transmission channels can be combined with an increase in the periodicity of data transmission, a modification of the data transmission power and a reduction in the amount of data transmitted from the wheel unit 11, 12, 13, 14 to the centralized control unit 6 of the motor vehicle 5. .

[0039] The activity strategy may also include the shutdown of ancillary functions provided by the wheel unit 11, 12, 13, 14. For example, the shutdown of ancillary functions may be signaled to the centralized control unit 6 so as to ensure only the minimum functions necessary for the safety of the user of the motor vehicle 5. Depending on the energy saving requirement, the shutdown of ancillary functions provided by the wheel unit 11, 12, 13, 14 may be combined with an increase in the data transmission periodicity, a modification of the data transmission power, a decrease in the number of data transmission channels and a decrease in the amount of data transmitted from the wheel unit 11, 12, 13, 14 to the centralized control unit 6 of the motor vehicle 5.

[0040] The transmission strategy may also include frequency control of the quartz crystal and / or the microprocessor in order to reduce the energy consumption of the wheel unit 11, 12, 13, 14. This embodiment of the invention is particularly suitable when at least one means of transmitting the data 31, 32, 33, 34 is represented by a Bluetooth®-type transmission means. Indeed, the constraints of advanced functions require high transmission frequencies and therefore higher energy consumption. These constraints can be relaxed during extreme measured temperatures. For example, at 48 MHz, a Bluetooth® component that consumes 1.3 mA is reported to consume only 400 pA at 16 MHz instead of 433 pA if it were proportional.Depending on the energy saving requirement, the frequency control of the quartz and / or the microprocessor can be combined with an increase in the periodicity of data transmission, a modification of the data transmission power, a decrease in the number of data transmission channels, a decrease in the amount of data transmitted. from wheel unit 11, 12, 13, 14 to centralized control unit 6 of motor vehicle 5, at standstill of auxiliary functions provided by wheel unit 11, 12, 13, 14.

[0041] The method according to the invention optimizes the lifespan of a wheel unit 11, 12, 13, 14 by limiting its energy consumption. The imposed strategy may have consequences for the user experience of the motor vehicle 5, but nevertheless guarantees compliance with regulations. The imposed strategy remains adaptable to the situations that the user may encounter.

[0042] According to a particular embodiment of the invention, the data emission strategy is imposed in response to a temperature measurement T by the data sensor 21, 22, 23, 24 of the wheel unit 11, 12, 13, 14. Indeed, it is known that temperature plays a role in the energy consumption of electrical components. It is therefore all the more necessary to limit the energy consumption of the wheel unit 11, 12, 13, 14 as a function of the temperature T of the wheel 1, 2, 3, 4, and in particular when the wheel unit 11, 12, 13, 14 is exposed to high or very low temperatures.

[0043] The method according to the invention, as illustrated in Figure 2, also allows the data transmission strategy to be adapted according to the temperature T of the wheel 1, 2, 3, 4. A so-called normal transmission strategy (step E40) can thus be defined when the measured temperature T (in a step E10) is between a first predetermined threshold T1 and a second predetermined threshold T2. Indeed, a temperature range can be defined in which the temperature will have a minimal influence on the energy consumption of the components.

[0044] For example, the first predetermined threshold T1 can be between +75°C and +120°C, preferably +90°C. The second predetermined threshold T2 can be between -40°C and +35°C, preferably -20°C.

[0045] Conversely, it is necessary to impose the data transmission strategy on the wheel unit 11, 12, 13, 14 when the measured temperature T of wheel 1, 2, 3, 4 (in step E10) is above the first predetermined threshold T1 (in step E20) or below the second predetermined threshold T2 (in step E30). High temperatures will increase the power consumption of the components at rest. Therefore, it is necessary to reduce energy consumption by imposing the data transmission strategy in order to optimize the lifespan of the wheel unit 11, 12, 13, 14.

[0046] In addition, low temperatures also induce premature aging of the battery of the wheel unit 11, 12, 13, 14. It is therefore necessary to reduce stress on the battery when it is exposed to such temperatures.

[0047] Moreover, the measurement of temperature T by the wheel unit 11, 12, 13, 14 also makes it possible to recognize the phases of the day that require little or no data transmission from the wheel unit 11, 12, 13, 14 to the centralized control unit 6 of the motor vehicle 5. For example, the wheel unit 11, 12, 13, 14 can detecting a temperature drop or stagnation during a 24-hour cycle indicates that vehicle 1 is parked. A data transmission strategy can then be imposed to drastically reduce or even prohibit data transmission from wheel units 11, 12, 13, 14 to the centralized control unit 6 of the motor vehicle 5.

[0048] Furthermore, when the wheel unit 11, 12, 13, 14 is equipped with a Bluetooth® type data transmission means 31, 32, 33, 34, it is possible to have a bidirectional link between the centralized control unit 6 and the wheel unit 11, 12, 13, 14. It is then possible to control the wheel unit 11, 12, 13, 14 by the centralized control unit 6. For example, a user profile can be defined on a 24-hour cycle and different data transmission strategies can be imposed during the cycle.

[0049] Thus, an activity strategy also consists of recognizing the phases of the day that require little or no monitoring, such as nighttime. These phases can be detected by the wheel unit 11, 12, 13, 14, which observes a drop in temperature during this 24-hour cycle, or by a resynchronization system using the bidirectional link offered by BLE communication (acronym for "Bluetooth® Low Energy").

[0050] The method according to the invention is suitable for any type of vehicle comprising one or more wheels, each equipped with at least one wheel unit.

[0051] The invention also relates to a device for implementing the method according to the invention. Such a device may, in particular, be an electronic chip incorporating a computer program product for implementing the method according to the invention.

Claims

Demands

1. A method for optimizing the lifespan of a wheel unit (11, 12, 13, 14) included in a wheel (1, 2, 3, 4, 5) of a motor vehicle (5), said wheel unit (11, 12, 13, 14) comprising a data sensor (21, 22, 23, 24) and at least one means for transmitting data (31, 32, 33, 34) from the wheel unit (11, 12, 13, 14) to a centralized control unit (6) of the motor vehicle (1), characterized in that the wheel unit (11, 12, 13, 14) is subjected to an activity strategy based on the temperature (T) measured by the data sensor (21, 22, 23, 24) so ​​as to reduce the energy consumption of the wheel unit (11, 12, 13, 14).

2. A method according to claim 1, characterized in that the activity strategy includes increasing the periodicity of data emissions from the wheel unit (11, 12, 13, 14) to the control unit (6).

3. Method according to claim 2, characterized in that the periodicity of data emissions is between 60 seconds and 600 seconds.

4. A method according to any one of the preceding claims, characterized in that the activity strategy includes modifying the data transmission power.

5. A method according to any one of the preceding claims, characterized in that the activity strategy includes reducing the amount of data transmitted from the wheel unit (11, 12, 13, 14) to the centralized control unit (6).

6. A method according to any one of the preceding claims, characterized in that when at least one data transmission means (31, 32, 33, 34) is represented by a multi-channel transmission means, the activity strategy includes reducing the number of data transmission channels.

7. A method according to any one of the preceding claims, characterized in that the activity strategy is imposed when the temperature (T) measured by the data sensor (21, 22, 23, 24) is greater than a first predetermined threshold (T1) or less than a second predetermined threshold (T2).

8. Method according to claim 7, characterized in that the first predetermined threshold (Tl) is between +75°C and +120°C, preferably +90°C.

9. Method according to claim 7 or 8, characterized in that the second predetermined threshold (T2) is between -40°C and +35°C, preferably -20°C.

10. Device for implementing the method according to any one of the preceding claims.

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