CLEANING SYSTEM FOR A MOTOR VEHICLE

Description

[0001] The invention relates to systems for cleaning a motor vehicle surface, in particular motor vehicle sensors, intended to be installed on a motor vehicle, more particularly those comprising several cleaning devices.

[0002] Many automotive sensors are located in areas where they are exposed to various types of contamination. Examples include various driver assistance cameras, distance sensors, ultrasonic sensors, radars, lidars, and rain sensors located on the vehicle. These sensors are very common in autonomous vehicles, which, by definition, must be able to drive without user intervention.

[0003] However, this dirt can lead to a malfunction of these sensors. It is therefore necessary to provide several cleaning devices for these sensors (scattered throughout the vehicle) to ensure their proper functioning over time, for example a cleaning device placed at the front of the vehicle and another placed at the rear of the vehicle. It is also possible that icing forming on a sensor can lead to a malfunction of the latter.

[0004] Conventionally, such cleaning devices are composed of a reservoir in which cleaning liquid is stored and a fluid distribution circuit composed of different pipes or hoses for conveying the cleaning liquid to at least one cleaning nozzle placed in front of a sensor so as to spray cleaning liquid onto the latter (there are generally several cleaning nozzles for several sensors).

[0005] Document EP 3 640 100 A1 presents a cleaning device as known in the prior art.

[0006] A pump for injecting cleaning fluid into the fluid distribution system and into the cleaning nozzle is usually mounted directly on the tank. Specifically, a liquid inlet tube from the pump is force-fitted into an opening in the tank (a seal ensures the assembly is watertight), and the liquid outlet is connected to the fluid distribution system.

[0007] When a sensor malfunction due to the presence of dirt is detected (automatically for example), the pump draws cleaning liquid from the tank, the liquid being at a pressure similar to atmospheric pressure (the pressure depends on the height of cleaning liquid in the tank), and propels it into the fluid distribution circuit at a higher pressure (the pressure difference being dependent on the size of the pump). The pressurized cleaning liquid is projected by the cleaning nozzle onto the sensor.

[0008] Thus, the various cleaning devices make it possible to clean all the sensors present on the vehicle so that they function optimally.

[0009] For example, it is possible for a vehicle to comprise two cleaning devices as described above, one placed at the front and the other at the rear of the vehicle. Each device comprises a cleaning liquid reservoir and at least one cleaning nozzle, the two being connected by a fluid distribution circuit. Each cleaning device comprises its own pump for delivering pressurized cleaning liquid to the cleaning nozzle(s). These cleaning devices operate independently of each other, cleaning surfaces at the front and rear of the vehicle respectively.

[0010] However, such a system has a drawback, particularly in the event of a malfunction.

[0011] Indeed, and in the case of a vehicle comprising, as described above, two (or even more than two) cleaning systems, one of the cleaning devices on board the vehicle may no longer function due to a failure of the pump intended to project cleaning liquid into the fluid distribution circuit. No liquid can therefore be taken from the tank to be conveyed to the cleaning nozzle(s) supplied by the faulty pump. The operation of the sensors placed in a certain area of ​​the vehicle (for example at the front or rear of the latter) may therefore be impaired, which may become critical, particularly with regard to autonomous vehicles for which the proper functioning of the sensors is a major issue.

[0012] The invention aims in particular to provide a system for cleaning motor vehicle surfaces intended to be installed on a motor vehicle comprising means allowing operation, even degraded, of a cleaning device having damage to the pump intended to supply the cleaning nozzle(s).

[0013] To this end, the subject of the invention is a cleaning system intended to be installed on a motor vehicle and comprising at least a first and a second cleaning device, each cleaning device comprising a cleaning liquid reservoir, at least one cleaning nozzle for spraying the cleaning liquid, a fluid distribution circuit arranged to convey cleaning liquid from the reservoir to the cleaning nozzle and a pump arranged to inject the cleaning liquid contained in the reservoir into the fluid distribution circuit, the cleaning system further comprising a bypass device connecting at least two cleaning devices at their respective fluid distribution circuits, comprising an emergency line and a solenoid valve placed on the emergency line controlled as a function of the failure state of a pump,and arranged to supply the cleaning nozzle of a cleaning device from the reservoir of another cleaning device, each cleaning device comprising between its reservoir and a connection point to the bypass device a non-return member.,

[0014] This makes it possible to compensate for a breakdown in a cleaning device by supplying it with cleaning liquid from another cleaning device.

[0015] When all cleaning devices are operating, the bypass device solenoid valve is closed and fluid communication between the cleaning devices is impossible.

[0016] However, when the pump of a cleaning device is no longer capable of sending cleaning liquid to the cleaning nozzle, this fault is detected (for example by self-diagnosis). From then on, the solenoid valve of the bypass device opens and the functional pump of another cleaning device is activated to supply the cleaning nozzle(s) of the inoperative cleaning device. Thus, it is possible to ensure operation, even degraded, of the latter. The presence of non-return devices makes it possible to ensure that the cleaning liquid injected via the bypass device is properly directed to the cleaning nozzles of the inoperative cleaning device.

[0017] Depending on other optional features of the cleaning system taken alone or in combination: the first cleaning device is for example placed at the front of the motor vehicle and the second cleaning device is for example placed at the rear of the motor vehicle. Thus, the motor vehicle comprises different cleaning devices distributed as close as possible to the areas to be cleaned; the bypass device may comprise a bidirectional pump placed on the emergency line. Thus, this pump makes it possible to avoid pressure losses during the passage of cleaning liquid in the emergency line to supply a faulty cleaning device, regardless of the faulty cleaning device; the non-return member may comprise a non-return valve. A simple assembly is therefore obtained; the non-return member may comprise a solenoid valve, preferably present at the pump arranged to inject the cleaning liquid contained in the reservoir into the fluid distribution circuit.The advantage of this solution lies in the fact that the solenoid valve can be closed to act as a non-return device but also be opened, for example to fill an empty tank of a cleaning device with cleaning liquid from the tank of another cleaning device; the cleaning system can comprise more than two cleaning devices, the fluid distribution circuit of a cleaning device being able to be connected to at least one fluid distribution circuit of other cleaning devices via a bypass device.Thus, it is possible to create pairs of cleaning devices, each cleaning device being able to compensate for a failure of the other, or to connect all the cleaning devices on board a motor vehicle; each cleaning device may comprise a liquid distributor connecting a primary pipe coming from the pump to a series of secondary pipes coming from several cleaning nozzles and a pilot unit configured to close the liquid distributor of a cleaning device depending on the failure state of the pump of another cleaning device.Thus, and in the event of failure of the first cleaning device, the distributor of the second cleaning device, in particular the solenoid valves present in this distributor, can be closed to ensure that all the cleaning liquid taken from the reservoir of the second cleaning device is sent into the fluid distribution circuit of the first cleaning device and to the cleaning nozzles of the latter; the cleaning system can comprise a circuit for monitoring an operating state of the first and second cleaning devices and a control unit connected to the monitoring circuit and configured to open the solenoid valve of the bypass device.Thus, automatic detection of a failure of a cleaning device is obtained and the commissioning of the bypass device in response to this diagnosis; the monitoring circuit can be configured to detect a failure state of the pump of the first or second cleaning device. The aim is therefore specifically to target the failure of the pumps used to draw cleaning liquid from the tanks of the cleaning devices; the monitoring circuit can comprise a pressure sensor arranged upstream of the pump and another arranged downstream of the pump and upstream of the non-return member.Here we have an example of an assembly making it possible to observe, for example, a lack of pressure downstream of the pump indicating a failure of the latter and therefore a failure of the cleaning device; and the monitoring circuit is in particular configured to detect that a liquid level inside the reservoir of the first or second cleaning device is below a predetermined threshold value. Thus, it is possible, for example, to envisage filling this reservoir with another reservoir in order to allow the cleaning device to continue to operate. If the architecture of the cleaning system does not allow such filling, then the detection of an insufficient level of cleaning liquid allows another cleaning device to supply the cleaning nozzles via the emergency line.

[0018] The invention also relates to a method for cleaning motor vehicle sensors using the cleaning system according to the invention comprising the following steps: detecting a failure of the first cleaning device, controlling the opening of the solenoid valve of the bypass device, and controlling the operation of the pump of the second cleaning device to inject cleaning liquid into the emergency line up to the cleaning nozzle of the first cleaning device.

[0019] Thus, and as explained above, it is possible to continue to operate a faulty cleaning device, at least in degraded mode, by using another cleaning device to supply the fluid distribution circuit and the cleaning nozzles of the faulty cleaning device.

[0020] Depending on other optional features of the cleaning process taken alone or in combination:the step of controlling the operation of the pump of the second cleaning device may be combined with a control of the operation of a bidirectional pump placed on the emergency line. Thus, the operation of two pumps in series makes it possible to limit or even compensate for pressure losses due to the circulation of the cleaning liquid from the reservoir of the second cleaning device to the cleaning nozzles of the first cleaning device; the method may comprise a step of closing a liquid distributor of the second cleaning device connecting a primary pipe coming from the pump of the second cleaning device to a series of secondary pipes coming from several cleaning nozzles of the second cleaning device after detecting a failure of the first cleaning device.Thus, and in the event of failure of the first cleaning device, the distributor of the second cleaning device, in particular the solenoid valves present in this distributor, can be closed to ensure that all the cleaning liquid taken from the reservoir of the second cleaning device is sent into the fluid distribution circuit of the first cleaning device and to the cleaning nozzles of the latter; the failure of the first cleaning device can be detected by a circuit for monitoring an operating state of the first and second cleaning devices, the opening command of the solenoid valve of the bypass device being controlled by a control unit. Thus, automatic detection of a failure of a cleaning device is obtained and the commissioning of the bypass device in response to this diagnosis; . the monitoring circuit can detect a failure of the pump of the first cleaning device. This therefore specifically targets the failure of the pumps used to draw cleaning liquid from the tanks of the cleaning devices; and the failure of the pump of the first cleaning device can be detected by pressure measurements taken by a pressure sensor arranged upstream of the pump and another arranged downstream of the pump and upstream of the non-return member. Here we have an example of an assembly making it possible to observe, for example, a lack of pressure downstream of the pump, indicating a failure of the latter and therefore a failure of the cleaning device. Brief description of the figures

[0021] The invention will be better understood on reading the following description, given solely by way of example and with reference to the appended drawings in which: There figure 1is a schematic representation of the cleaning system according to the invention comprising a first and a second cleaning device in operating condition; The figure 2 is a schematic representation of the cleaning system of the figure 1 , the first cleaning device being faulty; The figure 3 is a schematic representation of the cleaning system of the figure 1 illustrating a filling of a reservoir of the first cleaning device by the second cleaning device; The figure 4 is a schematic representation of a cleaning system according to a variant of the invention, the first cleaning device being faulty; The Figure 5 is a schematic representation of the different stages of the cleaning method according to the invention in the event of failure of a cleaning device; and The figure 6is a schematic representation of the different stages of the cleaning process when the tank of a cleaning device is filled by another cleaning device.

[0022] The embodiments described with reference to the figures are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Single features of different embodiments can also be combined to provide other embodiments.

[0023] By "upstream" or "downstream", we locate the elements / equipment in the direction of transport of the flow of material to be treated. Thus, a first piece of equipment or element, for example a pump, is located upstream of a second piece of equipment or element if the material is first treated by the first piece of equipment and then the second piece of equipment. Detailed description

[0024] We now refer to the figure 1 representing a cleaning system 2 on board a motor vehicle 4. This cleaning system 2 aims to allow the cleaning of different surfaces of the motor vehicle 4 such as, for example, sensors on board the vehicle or the windshield or the rear window. The figures include arrows 32 illustrating the direction of circulation of the cleaning liquid depending on the operating state of the cleaning system 2.

[0025] The cleaning system comprises, in the illustrated example, a first cleaning device 6 placed at the front of the vehicle and a second cleaning device 8 placed at the rear of the vehicle.

[0026] Each cleaning device comprises a reservoir 10 of cleaning liquid on which a pump 12 is mounted. The pump 12 is mounted in a recess of the reservoir 10 intended to receive the pump 12, the reservoir 10 comprising an orifice through which an inlet tube of the pump 12 is mounted, with a seal at the interface between the reservoir 10 and the pump 12 at the orifice to ensure the sealing of the assembly. The pump 12 is conventionally a standard pump comprising for example a main body of tubular shape. This main body may be composed of a first pumping part and a second drive part comprising an electric motor. The first pumping part comprises a liquid inlet tube and a liquid discharge tube in order to be able to receive cleaning liquid from the reservoir 10 and to discharge it at a pressure higher than the inlet pressure of the pump 12.The liquid inlet tube may be placed at a free end of the first pumping part and be coaxial with the main body of the pump 12 by sharing the same axis of revolution with the latter. The second discharge part may extend from the first pumping part in a direction perpendicular to the axis of revolution of the main body.

[0027] The second drive part may be located above the first pumping part and comprise an electric motor and, at its free end, a connector for connecting the pump 12 to an electrical power source.

[0028] Several cleaning nozzles (not shown in the figures) are located at the other end of the cleaning devices 6 and 8 and intended to be placed in front of a surface of the motor vehicle to be cleaned in order to spray pressurized cleaning liquid there.

[0029] Each cleaning device further comprises pipes (or conduits) connecting the different components (pump 12, cleaning nozzle, etc.) to each other to form a fluid distribution circuit 14.

[0030] Each cleaning device may comprise, in the case where the same reservoir 10 supplies several cleaning nozzles, a liquid distributor 16 making it possible to connect a primary pipe 18 coming from the pump 12 to a series of secondary pipes 20 coming from several cleaning nozzles, as illustrated in the figures. Conventionally, the latter may comprise one or more solenoid valves to allow or not the supply of the secondary pipes 20. It is possible to envisage the presence of a solenoid valve at the primary pipe at the inlet of the liquid distributor 16 to control the supply of all the secondary pipes 20 or solenoid valves on each secondary pipe 20 for specific control of the supply of each cleaning nozzle. Any type of solenoid valve may be used, for example a solenoid valve, normally open or closed.

[0031] The cleaning system may also comprise a control unit 21 for controlling the opening and closing of the liquid distributor, for example solenoid valves, in order for example to cut off the power supply to the cleaning nozzles of an operational cleaning device to ensure that the cleaning liquid from the latter is properly redirected to a faulty cleaning device.

[0032] The cleaning system 2 further comprises a bypass device 22 connecting the two cleaning devices 6 and 8 at their respective fluid distribution circuits 14.

[0033] The bypass device 22 comprises a backup line 24 connecting the fluid distribution circuit 14 of the first cleaning device 6 to the fluid distribution circuit 14 of the second cleaning device 8, preferably between the pump 12 and the liquid distributor 16 of each cleaning device. This creates a fluid communication between the two cleaning devices making it possible to supply one with the cleaning liquid stored in the reservoir 10 of the other.

[0034] The bypass device 22 also comprises a solenoid valve 26 placed on the emergency line 24 and controlled according to the failure state of a pump. In other words: the solenoid valve 26 is closed when the two cleaning devices are operational in order to avoid fluid communication between them, as can be seen in the figure 1, but the solenoid valve 26 is open when one of the two cleaning devices is faulty and this in order to allow the operational cleaning device to operate the other, at least in degraded mode, as can be seen on the figures 2 , 3 and 4 .

[0035] Any type of solenoid valve can be used, for example a solenoid valve, preferably normally closed.

[0036] In the case where the number of cleaning devices is greater than two, it is possible to arrange for each cleaning device to be connected to another cleaning device or even more, even considering a connection of all the cleaning devices to each other via branch devices 22.

[0037] Each cleaning device comprises between its tank 10 and a connection point to the bypass device a non-return member 28.

[0038] According to a first variant shown on the figures 1 to 3 , the non-return member 28 comprises a non-return valve allowing only the passage of liquid coming from the pump 12 of the cleaning device concerned. This is a simple way of preventing the cleaning liquid coming from a functional cleaning device from being poured back into the reservoir 10 of a faulty cleaning device.

[0039] According to a second variant illustrated in the figure 4 but also on the figure 3 , the non-return member 28 comprises a solenoid valve 29, 29A for the front cleaning device and 29R for the rear cleaning device, present at the level of the pump arranged to inject the liquid contained in the reservoir 10 into the fluid distribution circuit (case not illustrated in the figures). The advantage of this variant lies in having a dynamic system. In other words: during operation of the cleaning device, the solenoid valve 29 is open to allow the passage of cleaning liquid from the reservoir 10 and the solenoid valve 26 is closed, when the cleaning device is faulty, in particular a pump failure, the solenoid valve 29 is closed to prevent cleaning liquid from a functioning cleaning device from being poured back into the reservoir 10 of a faulty cleaning device and the solenoid valve 26 is open, and if it is necessary to fill the reservoir 10 with cleaning liquid of a cleaning device, but the pump 12 is functional, the solenoid valve 29 is open to allow cleaning liquid from another cleaning device to reach the reservoir 10.The control unit 21 of the liquid dispenser can close the latter in order to prevent cleaning liquid from escaping through the cleaning nozzles of the cleaning device whose reservoir 10 is to be filled. The liquid dispenser 16 of the cleaning device from which liquid is taken is also closed for the same reasons.

[0040] Considering this possibility of filling the tank 10 illustrated in the figure 3for the first tank, it is possible that the cleaning system 2 comprises a monitoring circuit 31 configured to detect that a liquid level inside the tank 10 of the first or second cleaning device is below a predetermined threshold value, for example by comprising a probe measuring the liquid level inside a tank 10. There could therefore be, after detection of an insufficient liquid level, filling of the tank 10 with cleaning liquid coming from another cleaning device with activation of the pump 12 of the latter, opening of the solenoid valve 26 of the bypass device 22 and opening of the solenoid valve 29A forming a non-return member. As illustrated in figure 3 , the valve(s) of the liquid distributors 16 of the two cleaning devices are closed to prevent any cleaning liquid from escaping through the cleaning nozzles when this is not desired.

[0041] In the case where the non-return member 28 comprises a non-return valve, an insufficient liquid level can therefore be assimilated to a failure leading to the cleaning nozzles being supplied by another cleaning device.

[0042] In the variant illustrated in the figure 4, the bypass device further comprises a bidirectional pump 30 placed on the emergency line. As explained previously, this makes it possible to compensate for the pressure losses due to the circulation of the cleaning liquid from the reservoir 10 of an operational cleaning device to the cleaning nozzles of a faulty cleaning device, regardless of the faulty cleaning device. It would even be possible, depending on the sizing of the bidirectional pump 30, to ensure that the pressure at the nozzle outlet is higher than that at the pump outlet 12 of the operational cleaning device. The absence of a bidirectional pump 30 nevertheless makes it possible to ensure at least degraded operation of the faulty cleaning device.

[0043] As explained previously, the cleaning system may comprise a monitoring circuit 31 for measuring the filling level of the reservoirs 10 of the first and second cleaning devices 6 and 8. This monitoring circuit 31 may of course be used to monitor the operating state of the first and second cleaning devices and therefore detect a failure of a cleaning device.

[0044] For example, the monitoring circuit 31 may be configured to specifically detect a failure state of the pump 12 of the first or second cleaning device 6 and 8. It is possible for the monitoring circuit 31 to comprise a pressure sensor arranged upstream of the pump 12 and another arranged downstream of the pump 12 and upstream of the non-return member 28. The observation of an absence of pressure rise downstream of the pump 12 leads to the observation of a failure of the cleaning device.

[0045] The monitoring circuit 31 can be connected to the control unit 21. Therefore, the detection of a fault by the monitoring circuit 31 is communicated to the control unit 21 which opens the solenoid valve 26 and can also start the pump of an operational cleaning device connected to the faulty cleaning device.

[0046] A mode of operation of the cleaning system as described above will be described in support of the figure 2 and of the figure 4 (variant comprising a solenoid valve 26 on the emergency line 24 and solenoid valves forming non-return members 28) in the event of failure of the first cleaning device 6. The operating mode is the same for a failure of the second cleaning device 8. The Figure 5 illustrates the different stages of this mode of operation.

[0047] The first step 34 consists of detecting a failure, for example of the first cleaning device 6. The latter can be detected in particular by the monitoring circuit 31. This can be a detection as described above, with sensors present upstream and downstream of the pump 12 or a probe measuring the level of liquid inside the tank 10. At this stage, an anomaly leading to a failure of the first cleaning device 6 has been diagnosed.

[0048] The second step 36 is the opening command of the solenoid valve 26 of the bypass device 22, for example by the control unit 21 coupled to the monitoring circuit. This opening command depends on the type of solenoid valve used. It is also possible to envisage a step 38 of closing the liquid distributor 16 of the second filling device 8 at this time but also the solenoid valve 29 forming the non-return member 28 of the first cleaning device 6. At this stage, the bypass device 22 can convey liquid from the second cleaning device 8 to the first cleaning device 6. If the liquid distributor 16 of the second cleaning device 8 has been closed as has the possible solenoid valve 29 forming the non-return member 28 at the first cleaning device 6, then everything is ready for the injection of liquid from the second cleaning device 8 to the first cleaning device 6.Step 36 and optional step 38 therefore prepare the redirection of the cleaning liquid.

[0049] The third step 40 is the control of the operation of the pump 12 of the or one of the second cleaning devices 8 to inject cleaning liquid into the emergency line 24 up to the cleaning nozzles of the first cleaning device 6. If a bidirectional pump 30 is present on the emergency line 24 as illustrated in the figure 4, then the latter is preferably activated in a synchronized manner with the pump 12 of the second cleaning device 8 (step 42 of the method). The liquid distributor 16 of the second cleaning device 8 as well as the solenoid valve 29 forming a non-return member 28 at the first cleaning device 6 can be closed during this step. Thus, cleaning liquid is taken from the reservoir 10 of the second cleaning device 8 and injected up to the cleaning nozzles of the first cleaning device 6 via the emergency line 24 of the bypass device 22.

[0050] Following this series of steps 34, 36 and 40 and when the operation of the first cleaning device is no longer necessary, for example after a repair or maintenance operation, the solenoid valve 26 can be switched back to the closed state, the bidirectional pump 30 can be deactivated as can the pump 12 of the second cleaning device 8 and all of the members that have been closed are reopened in order to ensure a return to the status quo ante (step 44 back to the initial situation).

[0051] In the case where it is desired to fill the reservoir 10 of the first cleaning device 6 with cleaning liquid coming from the reservoir 10 of the second cleaning device 8 (illustrated in figure 6 ), the following steps are followed: step 46 of detecting a level of cleaning liquid below a predetermined threshold value in the reservoir 10 of the first cleaning device 6, for example by a probe of the monitoring circuit, step 48 of controlling the opening of the solenoid valve 26 and potential closing of the liquid distributors 16 of the first and second cleaning devices 6 and 8 (step 50), the solenoid valve forming a non-return member 28 at the first cleaning device 6 being open (passively or actively depending on the type of solenoid valve, step 52), step 54 of controlling the operation of the pump 12 of a second cleaning device 8 to inject cleaning liquid into the emergency line 24 to the reservoir 10 of the first cleaning device 6. List of references

[0052] 2: cleaning system 4: motor vehicle 6: first cleaning device 8: second cleaning device 10: tanks 12: pumps 14: fluid distribution circuits 16: liquid distributors 18: primary pipe 20: secondary pipes 21: control unit 22: bypass device 24: emergency line 26: solenoid valve of the bypass device 28: non-return member 29, 29A, 29R: solenoid valves forming a non-return member 30: bidirectional pump 31: monitoring circuit 32: direction of the cleaning liquid 34: failure detection of the first cleaning device 36, 48: opening control of the solenoid valve of the bypass device 38: closing of the liquid distributor of the second device and of the solenoid valve forming a non-return member of the first device 40,54: operating control of the pump of the second device 42: activation of the bidirectional pump 44: return to the initial situation 46: detection of the cleaning liquid level below a threshold value 50: closing of the liquid distributors of the first and second devices 52: Opening of the solenoid valve forming the non-return member of the first device,

Claims

1. A cleaning system (2) suitable for being mounted on a motor vehicle (4) and comprising at least one first and one second cleaning device (6, 8), wherein each cleaning device (6, 8) comprises a cleaning liquid reservoir (10), at least one cleaning nozzle for spraying the cleaning liquid, a fluid distribution circuit (14) arranged to convey cleaning liquid from the reservoir (10) to the cleaning nozzle and a pump (12) arranged to inject the cleaning liquid contained in the reservoir (10) into the fluid distribution circuit (14), characterized in that the cleaning system (2) further comprises a bypass device (22) connecting at least two cleaning devices (6, 8) by their respective fluid distribution circuits (14), comprising a backup line (24) and a solenoid valve (26) placed on the backup line (24) controlled as a function of the failure state of a pump (12), and arranged to supply the cleaning nozzle of one cleaning device (6, 8) from the reservoir (10) of another cleaning device (6, 8), wherein each cleaning device (6, 8) comprises a non-return member (28) between its reservoir (10) and a point of connection to the bypass device (22).

2. The cleaning system (2) as claimed in claim 1, wherein the first cleaning device (6) is placed at the front of the motor vehicle (4) and the second cleaning device (8) is placed at the rear of the motor vehicle (4).

3. The cleaning system (2) as claimed in any one of the preceding claims, wherein the bypass device (22) comprises a two-way pump (30) placed on the backup line (24).

4. The cleaning system (2) as claimed in any one of the preceding claims, wherein the non-return member (28) comprises a non-return valve.

5. The cleaning system (2) as claimed in any one of the preceding claims, wherein the non-return member (28) comprises a solenoid valve, preferably present on the pump (12) arranged to inject the cleaning liquid contained in the reservoir (10) into the fluid distribution circuit (14).

6. The cleaning system (2) as claimed in any one of the preceding claims, comprising more than two cleaning devices (6, 8), wherein the fluid distribution circuit (14) of one cleaning device (6, 8) is connected to at least one fluid distribution circuit (14) of other cleaning devices (6, 8) by means of a bypass device (22).

7. The cleaning system (2) as claimed in any one of the preceding claims, wherein each cleaning device (6, 8) comprises a liquid distributor (16) connecting a primary pipe (18) coming from the pump (12) to a series of secondary pipes (20) coming from a plurality of cleaning nozzles, and a control unit (21) configured to close the liquid distributor (16) of one cleaning device as a function of the failure state of the pump (12) of another cleaning device.

8. The cleaning system (2) as claimed in any one of the preceding claims, comprising a circuit for monitoring an operating state of the first and second cleaning devices (6, 8), and a control unit (21) connected to the monitoring circuit and configured to open the solenoid valve (26) of the bypass device (22).

9. The cleaning system (2) as claimed in claim 8, wherein the monitoring circuit is configured to detect a failure state of the pump (12) of the first or second cleaning device (6, 8).

10. The cleaning system (2) as claimed in claim 9, wherein the monitoring circuit comprises one pressure sensor positioned upstream of the pump (12) and another positioned downstream of the pump (12) and upstream of the non-return member (28).

11. The cleaning system as claimed in any one of claims 8 to 10, wherein the monitoring circuit is configured to detect that a liquid level inside the reservoir (10) of the first or second cleaning device (6, 8) is below a predetermined threshold value.

12. A method for cleaning motor vehicle sensors using the cleaning system (2) as claimed in any one of the preceding claims, comprising the following steps: - detecting the failure of the first cleaning device (6), - commanding the opening of the solenoid valve (26) of the bypass device (22), and - commanding the starting of the pump (12) of the second cleaning device (8) in order to inject cleaning liquid in the backup line (24) to the cleaning nozzle of the first cleaning device (6).

13. The cleaning method as claimed in claim 12, wherein the step of commanding the starting of the pump (12) of the second cleaning device (8) is coupled with a command to start a two-way pump (30) placed on the backup line (24).

14. The cleaning method as claimed in any one of claims 12 and 13, the method comprising a step of closing a liquid distributor (16) of the second cleaning device connecting a primary pipe (18) coming from the pump (12) of the second cleaning device (8) to a series of secondary pipes (20) coming from a plurality of cleaning nozzles of the second cleaning device (8) after the failure of the first cleaning device (6) has been detected.

15. The cleaning method as claimed in any one of claims 12 to 14, wherein the failure of the first cleaning device (6) is detected by a circuit for monitoring an operating state of the first and second cleaning devices (6, 8), the command to open the solenoid valve (26) of the bypass device (22) being controlled by a control unit (21).