METHOD FOR MONITORING A RATE OF PARTICLES EMITTED BY A BRAKE UNIT, AND ASSOCIATED SYSTEM

Abstract

Method (100) for monitoring a rate of particles emitted by a brake unit installed in a vehicle, comprising: - measuring (101), on a brake bench or a roller bench, the rate of particles originating from the brake unit under one or more predetermined braking conditions; - establishing (102) a chart comprising, for each predetermined braking condition, a maximum rate of particles originating from the brake unit; - measuring (103) the rate of particles emitted by the brake unit during actual use of the vehicle; - verifying (104) whether the rate of particles emitted by the brake unit during said actual use of the vehicle is less than or equal to said maximum rate of particles emitted under said current braking condition, or whether the rate of particles emitted by the brake unit during said actual use is greater than said maximum rate. Abstract Figure: Figure 1

Description

Title of the invention: METHOD FOR MONITORING A RATE OF PARTICLES EMITTED BY A BRAKE UNIT, AND ASSOCIATED SYSTEM Technical field

[0001] The present disclosure relates to a method for monitoring a rate of particles emitted by a brake unit installed in a vehicle, and an associated system. Prior art

[0002] In order to limit the risks of fraud on the level of emission of polluting particles from a road vehicle (car, bus, heavy goods vehicle, etc.) or rail vehicle (train, tram, metro, etc.), current legislation requires that it be tested under real driving conditions. During these tests, a portable emissions measurement system, also called PEMS (by its acronym in English "portable emissions measurement Systems"), is used.

[0003] Such a PEMS system is bulky, which is why it cannot be permanently installed in the vehicle. The PEMS system therefore does not meet other standards that require the vehicle to be equipped with on-board sensors capable of detecting and measuring the emissions of polluting particles. The objective of such standards is to be able to control the level of polluting particle emissions not only during tests under real driving conditions, but also throughout the entire service life of the vehicle.

[0004] These polluting particles can come from the vehicle's exhaust pipe, but also from the vehicle's braking operations, in particular from the friction of a brake pad on a brake disc.

[0005] In the case of particles originating from braking operations, methods for measuring particle emissions punctually, in particular during tests, are known. However, at present, none of these methods makes it possible to measure the level of polluting particle emissions emitted during braking operations during the lifetime of the vehicle. Summary

[0006] The present disclosure improves the situation.

[0007] For this purpose, a method is proposed for monitoring a rate of particles emitted by a brake unit installed in a vehicle, the method comprising: - measure, on a brake bench or a roller bench, the rate of particles coming from the brake unit under one or more predetermined braking conditions; - establish a chart including, for each predetermined braking condition, a maximum rate of particles coming from the brake unit; - measure the rate of particles emitted by the brake unit during actual use of the vehicle equivalent to one of the predetermined braking conditions, called the current braking condition; - verifying whether the rate of particles emitted by the brake unit during said actual use of the vehicle is less than or equal to said maximum rate of particles emitted in said current braking condition, or whether the rate of particles emitted by the brake unit during said actual use is greater than said maximum rate of particles emitted in said current braking condition.

[0008] Measuring the rate of particles emitted by the brake unit during actual use of the vehicle, and comparing this rate of particles with the maximum rate indicated in the chart for a predetermined braking condition which is equivalent to actual use of the vehicle, makes it possible to monitor throughout the useful life of the vehicle whether or not the rate of particles emitted complies with the applicable standards.

[0009] Preferably, during actual use of the vehicle, the latter is in the braking phase.

[0010] As will be detailed, each predetermined braking condition can be characterized by one or more parameters, for example relating to the vehicle. In the present text, when it is indicated that the actual use of the vehicle is equivalent to one of the predetermined braking conditions (or that one of the predetermined braking conditions is equivalent to the actual use of the vehicle), it is meant that the vehicle operates with values ​​of these parameters equal to those of one of the predetermined braking conditions.

[0011] The chart can be established from the values ​​of the maximum particle rate originating from the brake unit for each predetermined braking condition tested on a brake bench or roller test bench. The value of the maximum particle rate obtained for each predetermined braking condition corresponds to the value of the particle rate originating from the brake unit above which the particle emission level is non-compliant with the applicable regulations and standards. A particle rate emitted by the brake unit during said actual use higher than the maximum rate compiled in the chart for the current braking condition shows that the vehicle is more polluting than the limits accepted by the applicable regulations and standards.

[0012] It is noted that the brake unit used when measuring particles on a brake bench or rollers may be a different brake unit than that installed on the vehicle, the two brake units being similar or identical.

[0013] In order to carry out the tests on a brake bench or rollers, a WLTP cycle of braking may be used, without this being limiting.

[0014] The brake or roller bench may be equipped with a measuring device, for example one or more sensors, for determining the rate of particles originating from the brake unit during each predetermined braking condition. In other cases, the rate of particles originating from the brake unit during each predetermined braking condition may be determined from one or more sensors on board the vehicle. Each sensor of the bench (brake or roller bench), or on board the vehicle may be a sensor for counting the particles originating from the brake unit during each predetermined braking condition. Alternatively, each sensor may be configured to measure a concentration in the air of the particles originating from the brake unit during each predetermined braking condition.

[0015] Thus, at the end of the brake bench or roller test phase, the particle rate from the brake unit under each predetermined braking condition is obtained. In certain cases, this particle rate may be accompanied by an associated standard deviation.

[0016] The vehicle may be a road vehicle (car, bus, heavy goods vehicle, etc.) or a rail vehicle (train, tram, metro, etc.).

[0017] The brake unit is for example a friction brake unit. The brake unit may comprise a brake pad and a rotating element. The rotating element is for example a brake disc rotated by a wheel of the vehicle. In such a case, two pads, each on one side of the disc, are advantageously provided. Each pad may comprise a lining and a shoe.

[0018] Alternatively, the rotating element is a wheel of the vehicle.

[0019] The lining is for example made of friction material. Outside of braking phases, each pad is generally at a distance from the rotating element, while during braking phases, the lining of each pad comes into contact with the rotating element. The friction between the lining and the disc can create particles, which are in particular polluting particles, for example fine particles.

[0020] A particle capture system may be provided in the vehicle to prevent polluting particles from being released into the environment.

[0021] It is noted that when the vehicle is an electric or hybrid vehicle, said maximum rate of particles coming from the brake unit obtained during the brake bench or roller tests can be corrected by coefficients defined in the global technical regulations applicable to wheeled vehicles, also known as GTR (from the English "Global Technical Regulations") approved by the United Nations.

[0022] According to one aspect, the method may further comprise reproducing a signal alert when the rate of particles emitted by the brake unit during said actual use is higher than said maximum rate of particles emitted in said current braking condition.

[0023] The alert signal thus makes it possible to inform a user of the vehicle when the rate of particles emitted by the brake unit during actual use of the vehicle is higher than the maximum rate of particles emitted in said current braking condition. In certain cases, the alert signal may comprise a visual signal, for example the lighting of a light device provided in the vehicle, in particular in its cabin. Alternatively or additionally, the alert signal may comprise an auditory signal, for example the reproduction of a sound inside the cabin of the vehicle.

[0024] In some cases, if the rate of particles emitted exceeds the maximum rate of particles emitted in said current braking condition, a system configured to block the movement of the vehicle may be provided.

[0025] According to one aspect, the measurement of the rate of particles emitted by the brake unit during said actual use of the vehicle can be made from a first sensor on board the vehicle.

[0026] Thanks to the use of the first sensor embedded in the vehicle, it is possible to continuously measure the rate of particles emitted by the brake unit throughout the vehicle's useful life, and not only during the test phases. This therefore makes it possible to detect a rate of particles that does not comply with the regulations when the vehicle is in service. The method can thus be implemented by OBM (On-board Monitoring) systems which evaluate, for example continuously, the particle emissions during the vehicle's useful life. Of course, the method can also be used during RDE (Real Drive Emission) type tests by retrofitting the vehicle.

[0027] In some cases, said first on-board sensor may also be used to make measurements on a brake bench or roller bench. In other cases, the brake bench or roller bench includes its own sensor to measure the rate of particles coming from the brake unit.

[0028] Of course, several on-board sensors for measuring the rate of particles emitted during said actual use can be on board the vehicle. In such a case, each sensor can detect particles having different sizes or maximum sizes.

[0029] According to one aspect, each predetermined braking condition may comprise at least one of the following parameters: - initial speed of the vehicle at the start of braking; and / or - final speed of the vehicle at the end of braking; and / or - braking deceleration; and / or - inertia at a wheel of the vehicle; and / or - torque to said wheel; and / or - assembly formed by a pad, and / or a brake disc and / or a caliper of the brake unit; and / or - activation or deactivation of a particle capture system possibly installed in the vehicle.

[0030] These parameters may be configured and monitored from a computer connected to the brake test bench or the vehicle being tested on a roller test bench. For example, an operator testing the brake unit on the brake test bench or roller test bench indicates on the computer the value of some or each of these parameters associated with the predetermined braking condition being tested. These values ​​may then be communicated by the computer to the brake test bench or roller test bench. Such communication may be done for example via a CAN data bus. The brake test bench or roller test bench is then activated to operate the brake unit according to the values ​​of the parameters of the predetermined braking condition being tested at each time.

[0031] Preferably, in order to establish the abacus as completely as possible, several combinations of values ​​of these parameters can be used when the measurements are made on a brake bench or on rollers. Each of the combinations constitutes a different predetermined braking condition.

[0032] As indicated, one of the parameters that can characterize each predetermined braking condition is the torque present at the vehicle wheel. In order to measure this parameter, one or more specific sensors can be used.

[0033] According to one aspect, the inertia at the wheel can be estimated from at least one of the following parameters: - pressure on one or more shock absorbers installed in the vehicle; and / or - fuel level in the vehicle; and / or - mechanical power supplied by a vehicle engine; and / or - number of users on board the vehicle: and / or - weight of a vehicle load; and / or - presence or absence of a trailer attached to the vehicle.

[0034] The value of some or each of these parameters can also be indicated on the computer connected to the brake or roller bench.

[0035] Preferably, in order to establish the abacus as completely as possible, several combinations of values ​​of these parameters can be used when the measurements are made on a brake bench or on rollers. Each of the combinations constitutes a different predetermined braking condition.

[0036] During actual use of the vehicle, the number of users on board the vehicle can be determined for example by detecting the number of seat belts that are fastened. Alternatively, the number of users on board during actual use of the vehicle can be determined from the detection of a weight greater than or equal to a determined value on each seat, or portion of seat in the case of bench seats.

[0037] During actual use of the vehicle, the weight of the vehicle's load can be determined from a sensor installed on axles connecting each wheel to the vehicle.

[0038] According to one aspect, the method may further comprise measuring the level of particles present in the environment before and / or during and / or after the vehicle operates according to said actual use equivalent to said current braking condition.

[0039] Thus, it is possible to know what is the rate of particles present in the environment which are not generated by the activation of the brake unit during the braking phases. This makes it possible to determine, when measuring the rate of particles emitted by the brake unit during the actual use of the vehicle equivalent to said current braking condition, what is the true rate of particles which was emitted during this actual use. This avoids counting as emissions from the monitored brake unit any particles which are present in the atmosphere for reasons unrelated to the activation of the brake unit (for example, those not originating from road traffic, those originating from the brake unit of another vehicle which has previously crossed the path of the monitored vehicle, or those emitted by the exhaust pipe or other parts of the monitored vehicle, among others).

[0040] It is noted that when the measurement of the particle rate is carried out on a bench, it is also possible to measure the rate of particles present in the atmosphere before, and / or during, and / or after the use of the brake unit in the predetermined braking condition(s) and which are not due to this use. It is therefore also avoided to count as emissions from the monitored brake unit any particles which are present in the atmosphere for reasons unrelated to carrying out the measurements on the brake bench or roller bench in the predetermined braking condition(s). Advantageously, if the rate of particles present in the atmosphere for reasons unrelated to the bench tests has been taken into account to establish the chart, it is also possible to measure the rate of particles present in the environment for reasons unrelated to the actual use equivalent to said current braking condition.The rate of particles emitted during said actual use is thus more comparable to the maximum rate of particles associated with said current braking condition.

[0041] In some cases, to measure the rate of particles present in the environment which is not due to the actual use of the vehicle equivalent to the braking condition current, a second sensor different from said first sensor is used. The second sensor can be installed at the front of the vehicle, for example in the radiator. Also, when this second sensor makes measurements during actual use of the vehicle equivalent to the current braking condition, said second sensor does not see the particles emitted by the brake unit, so that it only measures the particles present in the environment for other reasons. In other cases, said first sensor is configured to measure the rate of particles present in the environment before the vehicle operates according to the actual use equivalent to the current braking condition. In such a case, the first sensor is preferably positioned on a position in the vehicle which has direct contact with the ambient air.

[0042] According to another aspect, there is provided a system for implementing the method as described above, the system comprising a first sensor configured to measure the rate of particles emitted by the brake unit during actual use of the vehicle equivalent to said current braking condition.

[0043] The use of the first sensor makes it possible to easily implement the method described above. In some cases, the first sensor is also configured to measure on the brake bench or roller the rate of particles coming from the brake unit under each predetermined braking condition.

[0044] The first sensor is for example a particulate matter sensor, for example of the PM2.5 or PM10 type.

[0045] According to one aspect, said first sensor can be embedded in the vehicle. For example, the first sensor is installed in the air flow downstream of a brake. The sensor being embedded in the vehicle, the rate of particles emitted by the brake unit can be measured throughout the useful life of the vehicle.

[0046] According to one aspect, said first sensor may be installed close to the brake unit, in particular in an area of ​​homogeneous concentration of particles emitted by the brake unit. By homogeneous, it is meant here that the variation in the concentration of particles emitted by the brake unit is zero or negligible within a radius around the sensor 30 equal to a determined value, for example 50 cm. According to one example, the first sensor is located at a distance from the brake unit substantially equal to the distance separating the brake unit from the sensor used on a brake bench or roller bench to measure the particle levels coming from the brake unit under the predetermined braking conditions. Thus, the comparability of the particle level results during actual use and tests on a brake bench or roller bench is improved.

[0047] According to one example, the position of the first sensor in the vehicle can be optimized by fluid mechanics calculations or by analyzing the trajectories of the particles. on brake bench or rollers.

[0048] The first sensor is a sensor for determining the rate of particles originating from the brake unit during actual use of the vehicle. The first sensor may be a sensor for counting particles originating from the brake unit during each predetermined braking condition. Alternatively, the sensor may be configured to measure an airborne concentration of particles originating from the brake unit during actual use of the vehicle.

[0049] When the particle rates obtained during the brake bench or roller tests are obtained using a sensor on board the vehicle, this sensor may correspond to the first sensor or be another sensor also installed in the vehicle.

[0050] According to one aspect, the system may further comprise a second sensor configured to measure the level of polluting particles present in the environment before and / or during and / or after the vehicle operates according to said actual use equivalent to said current braking condition. It is thus possible to determine what is the level of polluting particles in the environment which are not due to said actual use of the vehicle. It is thus possible to zero the emission measurement of the brake unit before each braking phase of the vehicle.

[0051] According to one example, the second sensor is installed at the front of the vehicle, for example in the radiator.

[0052] The front of the vehicle is to be interpreted here according to a forward direction of travel of the vehicle.

[0053] According to an alternative, the first sensor can be placed in the vehicle at a position making it possible to measure the level of polluting particles present in the environment before the vehicle operates according to said actual use equivalent to said current braking condition. A single sensor, in this case said first sensor, would then be sufficient to zero the emission measurement of the brake unit before each braking phase of the vehicle.

[0054] According to one aspect, said first sensor can be configured to measure the rate of particles emitted by a plurality of brake units during actual use of the vehicle equivalent to said current braking condition. A single sensor thus makes it possible to measure this rate of particles for several brake units, thus reducing the size of the system. Brief description of the drawings

[0055] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which: Fig.l

[0056] [Fig.l] shows a schematic view of a brake unit for a motor vehicle according to an exemplary embodiment and an exemplary system for implementing a method for monitoring a rate of particles emitted by this brake unit. Fig. 2

[0057] [Fig.2] shows a schematic view of the brake unit of [Fig.l], of a particle capture system according to an exemplary embodiment, and of another exemplary system for implementing a method for monitoring a rate of particles emitted by this brake unit. Fig. 3

[0058] [Fig.3] shows a flowchart of a method for monitoring a rate of particles emitted by the brake unit of Figures 1 and 2 according to an exemplary embodiment. Fig. 4

[0059] [Fig.4] shows a flowchart of a method for monitoring a rate of particles emitted by the brake unit of figures 1 and 2 according to another exemplary embodiment. Fig. 5

[0060] [Fig.5] shows a flowchart of a method for monitoring a rate of particles emitted by the brake unit of Figures 1 and 2 according to yet another exemplary embodiment. Description of the embodiments

[0061] [Fig.l] schematically shows a brake unit 10 of a vehicle. The brake unit 10 is for example a friction brake unit. The brake unit 10 comprises a brake pad 12 and a rotating element 14.

[0062] In a known manner, the plate 12 comprises a lining and a sole or a lining carrier. The lining is made of friction material, also called “ferodo”, and fixed to the sole or the lining carrier.

[0063] The rotating element 14 is rotated about an axis of rotation A when the vehicle is in motion. The rotating element 14 is for example a wheel of the vehicle or a disc thereof rotated about the axis A by the wheel. The rotating element 14 is for example made of metallic material.

[0064] In [Fig.l], the plate 12, in particular its lining, is opposite, in a direction substantially parallel to the axis of rotation A, the rotating element 14. Alternatively, the plate 12, in particular its lining, could be opposite a radially external surface of the rotating element 14. By "radial" is meant here in a direction substantially perpendicular to the axis of rotation A. The plate 12 is configured to, outside the braking phases of the vehicle, be at a distance from the rotating element 14, and, during the braking phases of the vehicle, come with its lining bearing on the rotating element 14.

[0065] Preferably, when the lining of the plate 12 is opposite, according to a direction substantially parallel to the axis of rotation A, of the rotating element 14, a second pad, not visible in the figures but similar or identical to this pad 12, is located on the other side of the rotating element 14. In such a case, the second pad is advantageously aligned with the pad 12 in a direction substantially parallel to the axis of rotation A. Also, the two pads sandwich the rotating element 14 during the braking phases of the vehicle.

[0066] The support of the pad 12, or of the two pads, on the rotating element 14 generates a friction force between the lining of each pad and the rotating element 14 which progressively reduces the speed of rotation of the rotating element 14, until it eventually causes it to stop completely. Thus, the moving vehicle is braked. The friction between the lining of each pad and the rotating element 14 causes wear of the rotating element 14 and of the friction material of the lining, which generates particles. Such particles are generally polluting. For example, the polluting particles generated are fine particles.

[0067] In certain cases, in order to prevent polluting particles from being released into the environment, a particle capture system 16 is provided in the vehicle. The capture system 16 comprises, for example, a vacuum source 18 and a pneumatic circuit 20. Each pad of the brake unit 10 is connected to the vacuum source 18 via the pneumatic circuit 20. For example, the vacuum source 18 comprises an electric motor 22 and a suction turbine 24 which is driven by this electric motor 22.

[0068] In operation, the vacuum source 18 is capable of sucking, through the pneumatic circuit 20, the particles emitted by the wear of the linings and the rotating element 14.

[0069] Now a method 100, 110 will be described for monitoring a rate of particles emitted by the brake unit 10 according to two exemplary embodiments shown diagrammatically in FIGS. 3 and 4. The particles are in particular the polluting particles generated by the friction between the lining of each pad 12 and the rotating element 14. In the present text, by “rate” is meant a total quantity or a volume concentration of these polluting particles emitted at each instant t or during a determined period of time. Alternatively, by “rate” is meant a concentration of such polluting particles in the air at each instant t or during a determined period of time.

[0070] The method 100 comprises a first step 101 of measuring the emissions of the particles coming from the brake unit 10 on a brake bench or a roller bench under a plurality of predetermined braking conditions. The brake unit 10 is therefore tested on the brake bench or roller bench when it operates according to each of the predetermined braking conditions. In order to carry out these tests, a cycle WLTP braking can be used, without this being limiting.

[0071] Each predetermined braking condition may be characterized by one or more parameters, for example relating to the vehicle. Each predetermined braking condition may comprise at least one of the following parameters: - initial speed of the vehicle at the start of braking; and / or - final speed of the vehicle at the end of braking; and / or - deceleration of braking; and / or - inertia at a wheel of the vehicle; and / or - torque at this wheel; and / or - assembly formed by the pad 12, and / or the brake disc 14 and / or a caliper of the brake unit; and / or - activation or deactivation of the particle capture system 16 possibly installed in the vehicle.

[0072] These parameters may be configured and monitored from a computer connected to the brake or roller bench, without this being limiting. For example, an operator testing the brake unit 10 on the brake or roller bench indicates on the computer the value of some or each of these parameters associated with the predetermined braking condition being tested. These values ​​are then communicated by the computer to the brake or roller bench. Such communication may be done for example via a CAN data bus. The brake or roller bench is then activated to operate the brake unit 10 according to the values ​​of the parameters of the predetermined braking condition being tested at each time.

[0073] Preferably, several combinations of values ​​of these parameters can be used when the measurements are made on a brake bench or on rollers. Each of the combinations constitutes a different predetermined braking condition.

[0074] As indicated, one of the parameters that can characterize each predetermined braking condition is the torque present at the vehicle wheel. In order to measure this parameter, one or more specific sensors can be used.

[0075] As also indicated, another parameter that can characterize each braking condition is the inertia at the vehicle wheel. This can be estimated from at least one of the following parameters: - pressure on one or more shock absorbers installed in the vehicle; and / or - fuel level in the vehicle; and / or - mechanical power supplied by a vehicle engine; and / or - number of users on board the vehicle: and / or - weight of the vehicle load; and / or - presence or absence of a trailer attached to the vehicle.

[0076] The value of some or each of these parameters associated with the inertia of the wheel can also be indicated on the computer connected to the brake or roller bench. Preferably, several combinations of values ​​of these parameters can be used when the measurements are made on a brake or roller bench. Each of the combinations constitutes a different predetermined braking condition.

[0077] The brake or roller bench may be equipped with a device, for example one or more sensors, for determining the rate of particles originating from the brake unit 10 during each predetermined braking condition. In other cases, the rate of particles originating from the brake unit 10 during each predetermined braking condition may be determined from one or more sensors on board the vehicle. Each sensor of the brake or roller bench, or each sensor on board the vehicle, may be a sensor for counting the particles originating from the brake unit 10 during each predetermined braking condition. Alternatively, each sensor may be configured to measure an airborne concentration of the particles originating from the brake unit 10 during each predetermined braking condition.

[0078] Thus, at the end of the brake bench or roller test phase, the particle rate from the brake unit 10 is obtained in each predetermined braking condition. In certain cases, this particle rate may be accompanied by an associated standard deviation.

[0079] The obtained particle rate, possibly with its standard deviation, can be considered the maximum particle rate coming from the brake unit 10 under the respective predetermined braking condition.

[0080] Alternatively, the particle rate from the brake unit 10 in each predetermined braking condition can be established after repeating step 101 a plurality of times in the corresponding predetermined braking condition. At each repetition, a particle rate from the brake unit 10 is obtained in the predetermined braking condition tested. It is thus possible to establish the maximum particle rate from the brake unit 10 in each predetermined braking condition. The maximum rate then corresponds to the largest particle rate value obtained during the different repetitions.

[0081] The sensor(s) installed in the brake or roller bench, or the sensor(s) on board the vehicle is / are for example a particulate matter sensor, for example of the PM2.5 or PM10 type.

[0082] The method 100, 110 further comprises a step 102 of establishing a chart comprising, for each predetermined braking condition, the maximum rate of particles coming from the brake unit 10.

[0083] This chart is established from the values ​​of the maximum rate of particles coming from the brake unit 10 for each predetermined braking condition tested on a test bench. braking or rollers during step 101. The maximum particle rate value obtained for each predetermined braking condition corresponds to the particle rate value from the brake unit 10 above which the particle emission level is non-compliant with applicable regulations and standards.

[0084] In other words, the resulting chart constitutes a compilation of data in which, for each predetermined braking condition, the maximum particle rate from the brake unit 10 obtained during step 101 is recorded. It is considered that any particle rate value from the brake unit 10 equal to or lower than this maximum rate complies with the applicable regulations and standards.

[0085] It is noted that when the vehicle is an electric or hybrid vehicle, the maximum rate of particles coming from the brake unit 10 obtained during step 101 can be corrected by coefficients defined in the global technical regulations applicable to wheeled vehicles, also known as GTR (from the English “Global Technical Regulations”) approved by the United Nations.

[0086] As indicated previously, during step 101 a plurality of predetermined braking conditions are tested. Thus, the chart obtained can include the values ​​of the maximum rate of particles emitted by the brake unit 10 for a multitude of different predetermined braking conditions. The greater the number of predetermined braking conditions tested during step 101, the more complete the chart is.

[0087] The method 100, 110 further comprises a step 103 of measuring the rate of particles emitted by the brake unit 10 during actual use of the vehicle equivalent to one of the predetermined braking conditions, called the current braking condition.

[0088] By “equivalent to one of the predetermined braking conditions” is meant here that the vehicle operates with values ​​of the parameters used for the tests of step 101 equal to those of one of the predetermined braking conditions, which are called in the following “current braking condition”.

[0089] To know the value during actual use of the vehicle of the different parameters used to carry out the tests of step 101, the dashboard of the vehicle can be consulted. Furthermore, the number of users on board the vehicle can be determined for example by detecting the number of seat belts that are fastened. Alternatively, the number of users on board during actual use of the vehicle can be determined from the detection of a weight greater than or equal to a determined value on each seat, or portion of seat in the case of benches.

[0090] The weight of the vehicle load during actual use of the vehicle can be determined from a sensor installed on axles connecting each wheel to the vehicle

[0091] During actual use of the vehicle, it is in the braking phase.

[0092] To measure the rate of particles emitted by the brake unit 10 during actual use of the vehicle equivalent to the current braking condition, a first sensor 30, illustrated schematically in FIGS. 1 and 2, is installed in the vehicle.

[0093] It is noted that the position of the sensor 30 in these figures 1 and 2 does not necessarily represent an actual position of the sensor 30 on the vehicle. The sensor 30 can instead be positioned at several different locations on the vehicle. According to a non-limiting example, the sensor 30 is installed in the air flow downstream of a brake.

[0094] Advantageously, the sensor 30 is mounted in the vehicle near the brake unit 10, preferably at a position where the concentration of particles emitted by the brake unit 10 during the braking phases is homogeneous. By homogeneous, it is meant here that the variation in the concentration of particles emitted by the brake unit 10 is zero or negligible within a radius around the sensor 30 equal to a determined value, for example 50 cm. Advantageously, the sensor 30 is located at a distance from the brake unit 10 substantially equal to the distance separating the brake unit 10 from the sensor to measure the levels of particles emitted on a brake bench or roller test bench during step 101. Thus, the comparability of the particle level results during actual use according to step 103 and during the brake bench or roller test bench tests according to step 101 is improved.

[0095] In order to optimize the position of the sensor 30 in the vehicle, fluid mechanics calculations or an analysis of the trajectories of the particles on a brake bench or rollers during step 101 can be implemented. For example, to reduce the influence of the environment during the measurement on the vehicle, the sensor 30 can be mounted on the vehicle in a very heterogeneous particle emission zone, in particular near the fine particle emission front. It is also appropriate for the sensor 30 to be positioned at a location on the vehicle where it is protected from possible splashes of water or mud which may occur when the vehicle is moving.

[0096] It is noted that when the particle rates obtained during step 101 are obtained using a sensor on board the vehicle, this sensor may correspond to the first sensor 30 or be another sensor also installed in the vehicle.

[0097] The sensor 30 is a sensor for determining the rate of particles originating from the brake unit 10 during actual use of the vehicle equivalent to the current braking condition. The sensor 30 may be a sensor for counting particles originating from the brake unit 10 or for measuring a concentration in the air of these particles during actual use of the vehicle equivalent to the current braking condition. current braking.

[0098] The sensor 30 may be a particulate matter sensor, for example of the PM2.5 or PM10 type.

[0099] Of course, several on-board sensors 30 may be provided in the vehicle to measure the rate of particles emitted by the brake unit 10 during actual use equivalent to the current braking condition. In such a case, each sensor can detect particles having different sizes, or maximum sizes. Furthermore, since generally a brake unit 10 is provided for each rotating element 14 of the vehicle, each sensor 30 on-board the vehicle may be associated with a respective brake unit 10. Alternatively, a single sensor 30 may be associated with all the brake units 10. In this way, a single sensor 30 measures the rate of particles emitted by all the brake units 10, which makes it possible to reduce the size of the system.

[0100] It is also noted that the brake unit 10 used when measuring particles on a brake bench or rollers may be another brake unit 10 than that installed on the vehicle, the two brake units being similar or identical.

[0101] Thanks to the use of the first sensor on board the vehicle, it is possible to continuously measure the rate of particles emitted by the brake unit 10 throughout the useful life of the vehicle, and not only during the test phases. The method 100, 110 can thus be implemented by OBM (On-board Monitoring) systems which evaluate, for example continuously, the particle emissions during the useful life of the vehicle. Of course, the method can also be used during RDE (Real Drive Emission) type tests by retrofitting the vehicle.

[0102] Once the rate of particles emitted during the actual use of the vehicle of step 103 has been obtained, it is checked whether this rate complies with the applicable regulations and standards. For this purpose, the method 100, 110 comprises a step 104 comprising the verification that the rate of particles emitted by the brake unit 10 during the actual use according to step 103 of the vehicle is less than or equal to the maximum rate of particles emitted in the current braking condition, or that the rate of particles emitted by the brake unit 10 during this actual use is greater than the maximum rate of particles emitted in the current braking condition.

[0103] To implement step 104, the particle rate obtained during actual use according to step 103 is compared with the maximum particle rate value indicated on the chart for the current braking condition which was obtained during step 101.

[0104] If the particle rate obtained during step 103 is higher than the maximum rate indicated on the chart for the current braking condition, it is concluded that the particle rate emitted by the brake unit 10 does not comply with the regulations and applicable standards. If, on the contrary, the particle rate obtained during step 103 is less than or equal to the maximum rate indicated on the chart for the current braking condition, it is concluded that the particle rate emitted by the brake unit 10 complies with the applicable regulations and standards.

[0105] A rate of particles emitted by the brake unit 10 during step 103 higher than the maximum rate compiled in the chart for the current braking condition shows that the vehicle is more polluting than the limits accepted by the applicable regulations and standards.

[0106] In some cases, the vehicle may include a system for blocking the movement of the vehicle based on the rate of particles emitted during actual use according to step 103. For example, if the rate of particles emitted exceeds the maximum rate of particles emitted in said current braking condition, a system configured to block the movement of the vehicle may be activated.

[0107] The method 110 illustrated in [Fig. 2] differs from the method 100 of [Fig. 1] in that it comprises two additional steps 105 and 106.

[0108] Step 105 comprises measuring the level of particles present in the environment before subjecting the brake unit 10 to each brake bench or roller test according to step 101 described above.

[0109] The measurement of this step 105 can be obtained by the same measuring device used for the measurements of step 101, or for another measuring device comprising for example also one or more sensor(s).

[0110] Step 105 makes it possible to know what the particle rate is present in the environment before carrying out each test according to step 101. Thus, it is possible to zero the emission measurement of the brake unit 10 before each test on a brake bench or rollers. In this way, the maximum particle rate recorded on the chart for each predetermined braking condition does not take into account the particles already present in the environment before carrying out each brake bench or roller test of step 101.

[0111] In certain cases, step 105 may alternatively, or in a complementary manner, comprise measuring the level of particles present in the environment during and / or after each bench test carried out on the brake unit 10. Such measurements may also make it possible to take the measurement zero so that the maximum level of particles indicated on the chart does not take into account the particles present in the environment for reasons unrelated to the bench tests carried out. If this measurement is carried out during each bench test, it is preferable for the measuring device used to be placed in a position which does not see the particles emitted by the brake unit.

[0112] Step 106 includes measuring the level of particles present in the environment before the vehicle operates according to the actual use equivalent to the current braking condition, in accordance with step 103 described above. In certain cases, step 105 may alternatively, or in a complementary manner, comprise measuring the level of particles present in the environment during and / or after the actual use according to step 103.

[0113] According to one example, the measurement of the particle rate of step 106 is implemented by the on-board sensor 30. For this purpose, the sensor 30 may be arranged in the vehicle at a position which puts it in direct contact with the external environment of the vehicle. For example, in this configuration, the sensor 30 may be arranged in the air flow downstream of the brake.

[0114] Alternatively, the measurement of step 106 can be implemented by a second sensor 40, illustrated in [Fig. 2]. In certain cases, this sensor 40 also makes it possible to implement the measurement according to step 105, that is to say, the measurement of the rate of particles present in the environment before each test on a brake bench or rollers.

[0115] The sensor 40 is embedded in the vehicle. This sensor 40 may be different, similar or identical to the sensor 30.

[0116] It is noted that the position of the sensor 40 in [Fig. 2] is not representative of its true position in the vehicle, the sensor 40 being able to be positioned in several places in the latter. Advantageously, the sensor 40 is arranged in the vehicle in a position which puts it directly in contact with the external environment of the vehicle. The second sensor can for example be installed at the front of the vehicle, which also allows the sensor 40 not to see the particles emitted by the brake unit when the sensor 40 measures the particles present in the environment during actual use according to step 103.

[0117] This configuration with the first sensor 30 and the second sensor 40 makes it possible to place the sensor 30, responsible for measuring the rate of particles emitted during the actual use of step 103, in an optimal position in the vehicle for measuring the rate of particles emitted during this actual use, even if such a position is not directly in contact with the external environment of the vehicle. Indeed, the measurement of the rate of particles according to step 106 being carried out by the second sensor 40, the sensor 30 may not be directly in contact with the external environment of the vehicle.

[0118] Step 106 makes it possible to know what is the rate of particles present in the environment for reasons unrelated to the braking of the vehicle. This makes it possible to determine, when measuring the rate of particles emitted by the brake unit during actual use according to step 103, what is the true rate of particles which was emitted during this actual use. In other words, step 106 makes it possible to make the zero of the emission measurement of the brake unit 10. This avoids counting as emissions of the monitored brake unit 10 any particles that are present in the atmosphere for reasons unrelated to the emissions of the brake unit 10 (for example, those not originating from road traffic, those originating from the brake unit of another vehicle that has previously crossed the path of the monitored vehicle, or those emitted by the exhaust pipe or other parts of the monitored vehicle, among others).

[0119] If one of the steps 105, 106 is implemented, the other step 106, 105 is preferably also implemented. This makes it possible to improve the comparability of the particle rate obtained during step 103 with the maximum rate compiled in the chart for the current braking condition. However, it is also possible that only one of the steps 105 or 106 is implemented. In such a case, the particle rate present before the tests of step 101 or the actual use of step 103 may be considered negligible, or it may be considered equal to a previously chosen value.

[0120] [Fig. 5] shows a method 120 for monitoring the rate of particles emitted by the brake unit 10 according to another exemplary embodiment. This method 120 comprises all the steps of one of the methods 100, 110, and an additional step 107.

[0121] This step 107 comprises reproducing an alert signal when the rate of particles emitted by the brake unit 10 during the actual use of step 103 is greater than the maximum rate of particles emitted in the current braking condition.

[0122] The alert signal thus makes it possible to inform a user of the vehicle when the rate of particles emitted by the brake unit during actual use of the vehicle is higher than the maximum rate of particles emitted in the current braking condition. In certain cases, the alert signal may comprise a visual signal, for example the lighting of a light device provided in the vehicle, in particular in its cabin. Alternatively or additionally, the alert signal may comprise an auditory signal, for example the reproduction of a sound inside the cabin of the vehicle.

[0123] It is noted that thanks to the method described above, it is possible to monitor throughout the useful life of the vehicle whether the rate of particles emitted complies or not with the applicable standards.

[0124] Furthermore, as indicated previously, one of the parameters which modify the braking conditions is the assembly formed by the pad 12, and / or the brake disc 14 and / or the caliper of the brake unit which are installed in the vehicle. Depending on the type of pad, and / or brake disc and / or caliper, the values ​​of the rate of particles emitted by the brake unit may vary. Also, a rate of particles emitted which is above the maximum rate indicated in the chart may be indicative of the aftermarket installation of a non-compliant pad / disc, or pad / caliper, or pad / disc / caliper assembly.

[0125] Now a system will be described for implementing the method 100, 110, 120 described previously.

[0126] The system comprises the first sensor 30. As explained above, the sensor 30 is embedded in the vehicle and makes it possible to measure the rate of particles emitted by the brake unit 10 during actual use of the vehicle equivalent to the current braking condition (step 103).

[0127] As indicated previously, in certain cases the sensor 30 may also be configured to measure the rate of particles originating from the brake unit 10 during each predetermined braking condition in step 101. This measurement makes it possible to establish the chart in step 102, as already explained. The sensor 30 may also be configured to obtain the measurement of step 106, that is to say, the measurement of the rate of particles present in the environment for reasons unrelated to the actual use of the vehicle according to step 103.

[0128] In some cases, the system further comprises the second sensor 40, which is, as indicated previously, configured to measure the level of polluting particles present in the environment for reasons unrelated to the actual use according to step 103. As indicated previously, in some cases the sensor 40 may also be configured to measure, during step 105 described above, the level of particles present in the environment for reasons unrelated to the performance of each brake bench or roller test of step 101.

[0129] Further details regarding the characteristics, function and position of sensor 30 and sensor 40 have been indicated previously with reference to method steps 100, 110, 120. For the sake of brevity, these details are not repeated in the following.

[0130] When the measurements of steps 101 or 106 and / or the measurement of step 105 are obtained by the measuring device specific to the brake or roller bench, this measuring device is also included in the system for implementing the method 100, 110, 120. As indicated, the measuring device of the brake or roller bench may comprise one or more sensor(s).

[0131] The present disclosure is not limited to the method examples described above, only by way of example, but it encompasses all the variants that a person skilled in the art may envisage within the framework of the protection sought.

Claims

Claims

1. Method (100, 110, 120) for monitoring a rate of particles emitted by a brake unit (10) installed in a vehicle, the method comprising: - measuring (101), on a brake bench or a roller bench, the rate of particles originating from the brake unit (10) under one or more predetermined braking conditions; - establishing (102) a chart comprising, for each predetermined braking condition, a maximum rate of particles originating from the brake unit (10); - measuring (103) the rate of particles emitted by the brake unit (10) during actual use of the vehicle equivalent to one of the predetermined braking conditions, called the current braking condition;- checking (104) whether the rate of particles emitted by the brake unit (10) during said actual use of the vehicle is less than or equal to said maximum rate of particles emitted in said current braking condition, or whether the rate of particles emitted by the brake unit (10) during said actual use is greater than said maximum rate of particles emitted in said current braking condition.;

2. A method (100, 110, 120) according to claim 1, further comprising reproducing an alert signal when the rate of particles emitted by the brake unit (10) during said actual use is greater than said maximum rate of particles emitted under said current braking condition.

3. Method (100, 110, 120) according to one of the preceding claims, wherein each predetermined braking condition comprises at least one of the following parameters: - initial speed of the vehicle at the start of braking; and / or - final speed of the vehicle at the end of braking; and / or - deceleration of braking; and / or - inertia at a wheel of the vehicle; and / or - torque at the wheel; and / or - assembly formed by a pad (12), and / or a brake disc (14) and / or a caliper of the brake unit; and / or - activation or deactivation of a particle capture system (16) possibly installed in the vehicle.

4. Method (100, 110, 120) according to claim 3, wherein the wheel inertia is estimated from at least one of the following parameters: - pressure on one or more shock absorbers installed in the vehicle; and / or - fuel level in the vehicle; and / or - mechanical power supplied by an engine of the vehicle; and / or - number of users on board the vehicle; and / or - weight of a load of the vehicle; and / or - presence or absence of a trailer attached to the vehicle.

5. Method (100, 110, 120) according to one of the preceding claims, further comprising measuring the level of particles present in the environment before and / or during and / or after the vehicle operates according to said actual use equivalent to said current braking condition.

6. System for implementing the method (100, 110, 120) according to one of the preceding claims, the system comprising a first sensor (30) configured to measure the rate of particles emitted by the brake unit (10) during actual use of the vehicle equivalent to said current braking condition.

7. System according to claim 6, wherein said first sensor (30) is on board the vehicle.

8. System according to one of claims 6 or 7, wherein said first sensor (30) is installed near the brake unit (10), in particular in an area of ​​homogeneous concentration of particles emitted by the brake unit (10).

9. System according to one of claims 6 to 8, further comprising a second sensor (40) configured to measure the level of polluting particles present in the environment before and / or during and / or after the vehicle operates according to said actual use equivalent to said current braking condition.

10. System according to one of claims 6 to 9, wherein said first sensor (30) is configured to measure the rate of particles emitted by a plurality of brake units (10) during actual use of the vehicle equivalent to said current braking condition.

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