System, assembly and cleaning method for cleaning the sensing surface of a sensor - Patents.com

Abstract

The present invention relates to a cleaning system (1) for cleaning a detection surface of a sensor, characterized in that the cleaning system (1) comprises a cleaning device (10) having a plurality of nozzles (100) configured to deposit droplets (g1) of a liquid (Lq) on an acceleration surface located upstream of the detection surface, a reservoir (11) connected to the cleaning device (10) and configured to store the liquid (Lq), and an acceleration device (12) for accelerating the movement of the droplets (g1) of the liquid (Lq) from the acceleration surface onto the detection surface.

Description

[Technical Field]

[0001] The present invention relates to a system for cleaning the sensing surfaces of vehicle sensors, and is particularly, but not exclusively, applicable in the vehicle or construction sectors. [Background technology]

[0002] A person skilled in the art is aware of a system for cleaning the sensing surface of a sensor for a vehicle, said system comprising an airflow injection device for injecting an airflow onto the sensing surface of said sensor in order to remove obstacles located on said sensing surface that block and obstruct the field of view of said sensor, thus cleaning said sensing surface of said obstacles. These obstacles are water droplets or dirt. The sensing surface is a surface located within the field of view of the sensor.

[0003] A drawback of this prior art is that the cleaning system is not effective when the dirt or water droplets are small, which are very difficult to remove with airflow unless a very powerful airflow jet is used, which becomes very bulky and expensive. Summary of the Invention

[0004] The invention aims to propose a system for cleaning the sensing surfaces of vehicle sensors, which system makes it possible to clean the sensing surfaces of vehicle sensors in an effective manner.

[0005] To this end, the present invention provides a system for cleaning the sensing surface of a sensor, the cleaning system comprising: a cleaning device comprising a plurality of nozzles configured to deposit droplets onto an acceleration surface located upstream of said detection surface; a tank connected to the cleaning device and configured to store the liquid; a device for accelerating movement of said droplet from said acceleration surface to said detection surface; The present invention proposes a system comprising:

[0006] The use of droplets to clean the sensing surface of the sensor and the acceleration of these droplets has a sufficient amount of kinetic energy to engulf any obstructing elements that are on the sensing surface of the sensor, thus displacing the obstructing elements from the sensing surface so that the sensing surface is clean, and allows this to be done regardless of the size of the obstructing elements.

[0007] According to non-limiting embodiments, the aforementioned cleaning method may further comprise one or more of the following additional features, taken alone or in any technically possible combination:

[0008] According to one non-limiting embodiment, said detection surface and said acceleration surface form part of said sensor; or said detection surface and said acceleration surface do not form part of said sensor;

[0009] According to one non-limiting embodiment, said droplets have a volume between 2 μL and 50 μL.

[0010] According to one non-limiting embodiment, the liquid has a surface tension greater than the surface tension of the detection surface.

[0011] According to one non-limiting embodiment, the nozzles are spaced apart such that the droplets form a waterfront.

[0012] According to one non-limiting embodiment, said detection plane and said acceleration plane are on the same plane.

[0013] According to one non-limiting embodiment, said cleaning device further comprises a perforated bar connected on one side to said nozzle and on another side to said tank.

[0014] According to one non-limiting embodiment, said cleaning device further comprises a support element for said perforated bar.

[0015] According to one non-limiting embodiment, a portion of the detection plane partially coincides with a portion of the acceleration plane.

[0016] According to one non-limiting embodiment, the aforementioned accelerator comprises: an airflow jet, or a device consisting of a grid of electrodes configured to allow an electric current to pass through it; or a device configured to produce the Leidenfrost effect, or a device configured to synthesize ultrasonic waves propagating in an acceleration plane; or It is a device made up of particles of different polarities.

[0017] According to one non-limiting embodiment, an apparatus configured to synthesize ultrasonic waves propagating in an acceleration plane comprises at least one wave transducer acoustically coupled to the acceleration plane.

[0018] According to one non-limiting embodiment, the surface tension of the liquid is 78 mJ / m 2 and the surface tension of the detection surface is 20 mJ / m 2 is.

[0019] According to one non-limiting embodiment, said nozzle has a diameter of 1 to 6 mm.

[0020] According to one non-limiting embodiment, the aforementioned nozzles are spaced apart by a distance equal to the droplet diameter ±10%.

[0021] According to one non-limiting embodiment, said nozzle is positioned at a distance from the acceleration plane of between 0 and 100% of the diameter of the droplet.

[0022] According to one non-limiting embodiment, said detection surface and said acceleration surface are inclined at an inclination angle of more than 20°.

[0023] According to one non-limiting embodiment, the aforementioned nozzle is configured to deposit droplets at a pressure of 0.5 bar or less.

[0024] According to one non-limiting embodiment, said cleaning device further comprises protruding elements for said bars configured to protect said acceleration surfaces.

[0025] According to one non-limiting embodiment, said support element is also configured to receive said acceleration device.

[0026] According to one non-limiting embodiment, said cleaning device further comprises a distributor for distributing water to said nozzles.

[0027] According to one non-limiting embodiment, said water distributor is disposed between two sets of nozzles symmetrically distributed on either side of said water distributor.

[0028] As mentioned above, an assembly is proposed comprising the sensing surface of the sensor and the cleaning system.

[0029] According to one non-limiting embodiment, said detection surface and said acceleration surface form part of said sensor; or Said detection surface and said acceleration surface do not form part of said sensor.

[0030] According to one non-limiting embodiment, a portion of the detection plane partially coincides with a portion of the acceleration plane.

[0031] According to one non-limiting embodiment, said sensor is an optical sensor.

[0032] According to one non-limiting embodiment, the aforementioned sensors are vehicle sensors.

[0033] According to one non-limiting embodiment, the sensor is a radar, a lidar or a camera.

[0034] According to one non-limiting embodiment, said sensors are building sensors.

[0035] According to one non-limiting embodiment, said sensor is a solar panel or a photovoltaic panel.

[0036] 1. A method for cleaning a sensing surface of a vehicle sensor, comprising: depositing droplets by a plurality of nozzles of a cleaning device onto an acceleration surface of said sensor located upstream of said detection surface; and accelerating the movement of said droplet from said acceleration surface to said detection surface by means of an acceleration device.

[0037] The invention and its various applications will be better understood by reading the following description and examining the accompanying drawings. [Brief explanation of the drawings]

[0038] [Figure 1] 1 is a diagram of a system for cleaning a sensing surface of a sensor, comprising a cleaning device, a tank, and an acceleration device, according to one non-limiting embodiment of the present invention. [Figure 2] 2 is a perspective view of an assembly including a sensing surface of a sensor and a cleaning device of the cleaning system of FIG. 1 according to one non-limiting embodiment. [Figure 3] 3 is a side view of a cleaning device of the cleaning system of FIG. 2 according to one non-limiting embodiment. [Figure 4] 3 is a bottom view of the cleaning device of the cleaning system of FIG. 2 according to one non-limiting embodiment. [Figure 5] 3 is a first enlarged view of a portion of the cleaning apparatus of FIG. 2 according to one non-limiting embodiment. [Figure 6] FIG. 4 is an enlarged view of a portion of the first enlarged view of FIG. 3, according to one non-limiting embodiment. [Figure 7] 3 is a perspective view of a cleaning device of the cleaning system of FIG. 2 without a support element, according to one non-limiting embodiment. [Figure 8] 8 is a cross-sectional view of a cleaning device of the cleaning system of FIG. 7 according to one non-limiting embodiment. [Figure 9]3 is a perspective view of a support element of a cleaning device of the cleaning system of FIG. 2 according to one non-limiting embodiment. [Figure 10] 2 is a flow diagram of a method for cleaning a sensing surface of a sensor implemented by the cleaning system of FIG. 1 according to one non-limiting embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0039] Elements that are identical in terms of structure or function and that appear in different figures retain the same reference numerals unless otherwise indicated.

[0040] A system 1 for cleaning a sensing surface 20 of a sensor 2 according to the invention will now be described with reference to Figures 1 to 9 according to a non-limiting embodiment.

[0041] Sensor 2 is configured to perform a detection function. Sensor 2 includes a field of view, otherwise referred to as a detection field of view.

[0042] In one non-limiting embodiment, sensor 2 is an optical sensor.

[0043] In non-limiting embodiment variations, sensor 2 is a lidar, radar, or camera. In this case, sensor 2 is configured to detect static or dynamic objects. In the case of a radar, the radar is a sensor configured to emit radar waves and receive returning radar waves. In the case of a lidar, the lidar is a sensor configured to emit emitted laser light and receive returning waves. In the case of a camera, the camera is configured to capture electromagnetic radiation (IR, visible, UV).

[0044] In one non-limiting embodiment, sensor 2 is a solar panel or photovoltaic panel, where sensor 2 is configured to detect and capture solar energy.

[0045] In one non-limiting embodiment, sensor 2 is a vehicle sensor. In one non-limiting embodiment, the vehicle is an automobile. Automobile refers to any type of motorized vehicle. In one non-limiting embodiment, when sensor 2 is a vehicle sensor, and if it is a camera, the camera is positioned behind the rear windshield of the vehicle toward the top of the rear windshield. In another non-limiting embodiment, sensor 2 is a building sensor.

[0046] As shown in Figures 1 and 2, there is a detection surface 20 of the sensor 2. The detection surface 20 is the surface on which the sensor 2 performs its detection function. The detection surface 20 is therefore the surface located within the field of view of the sensor 2. The detection surface therefore covers said field of view. For example, in the case of a radar, this means that emitted and returning radar waves pass through the detection surface 20. For example, in the case of a lidar, this means that laser light and returning waves pass through the detection surface 20. As will be seen below, the detection surface 20 is associated with or forms part of the sensor 2.

[0047] The detection surface 20 is a surface that must be cleaned when it is covered with elements g2 that obstruct the field of view of the sensor 2 and therefore prevent the sensor from properly performing its detection function. Such elements g2 are otherwise referred to as obstruction elements g2. In a non-limiting exemplary embodiment, the obstruction elements g2 are water droplets or dirt. The water droplets are water droplets caused by rain or fog. These water droplets or dirt often remain stationary on the detection surface 20.

[0048] The detection surface 20 is otherwise referred to as the surface to be cleaned 20. In one non-limiting example, the surface to be cleaned 20 is 50 mm to 300 mm. This is the case, for example, for a vehicle sensor 2, such as a camera. In one non-limiting example, the surface to be cleaned 20 is 500 mm to 1500 mm in length and width. This is the case, for example, for a building sensor 2, such as a solar collector or photovoltaic sensor.

[0049] As shown in FIG. 1, the cleaning system 1 includes: a cleaning device 10; Tank 11 and an accelerator 12; Equipped with.

[0050] The elements of the cleaning system 1 are described in detail below.

[0051] The tank 11 of the cleaning system 1 will now be described in detail.

[0052] As shown in FIG. 1 , a tank 11 is connected to the aforementioned cleaning device 10 and configured to store a cleaning liquid Lq, otherwise referred to as liquid Lq. In one non-limiting example, the liquid Lq is water. In one non-limiting embodiment, the liquid is a superhydrophobic liquid. In one non-limiting embodiment, the liquid Lq has a surface tension γ3 that is greater than and far from the surface tension γ1 of the aforementioned detection surface 20. This facilitates the rolling of a droplet g1 of the liquid Lq on the detection surface 20. In one non-limiting example, the surface tension γ3 is 78 mJ / m 2 (millijoules per square meter). In one non-limiting example, the surface tension γ is equal to 20 mJ / m for a hydrophobic surface. 2 (millijoules / square meter). Note that the surface tension of windshield washer fluid (30 mJ / m 2 ) is relatively close to the surface tension γ1 of the detection surface 20. This makes it more difficult for the droplet g1 of the liquid Lq to roll. In the remaining description, the droplet g1 of the liquid Lq will be referred to as droplet g1.

[0053] The cleaning device 10 of the cleaning system 1 will now be described in detail.

[0054] As shown in Figure 2, the cleaning device 10 is positioned away from the surface 20 to be cleaned. Furthermore, as shown in Figures 2 and 5, the cleaning device 10, and in particular its nozzle 100 described below, is positioned above the acceleration surface 21 so as to be able to deposit droplets g1 of the liquid Lq onto the acceleration surface 21.

[0055] The acceleration surface 21 is a surface on which droplets g1 of the liquid Lq are deposited by the nozzle 100 of the cleaning device 10 and accelerated by the acceleration device 12 described below. The acceleration surface 21 is located upstream of the detection surface 20 with respect to the field of view of the sensor 2. "Upstream" is understood to mean that the acceleration surface 21 is located before the detection surface 20 in the direction of propagation of the liquid Lq. In one non-limiting embodiment, the acceleration surface 21 has a surface tension γ2 that is different from the surface tension γ1 of the detection surface 20 described above. This makes it possible to obtain a rolling angle for the droplets g1 of the liquid Lq that is greater than 80°, or greater than 90° or 160°.

[0056] 2, the detection surface 20 and the acceleration surface 21 are on the same plane, which makes it easier for the droplet g1 of the liquid Lq to slide and to displace the obstruction element g2.

[0057] In one non-limiting embodiment, the detection surface 20 and the acceleration surface 21 are inclined at an inclination angle greater than 20° relative to the reference axis. In a variation of this non-limiting embodiment, the detection surface 20 and the acceleration surface 21 are inclined at an inclination angle of 20° to 30° relative to the reference axis. In one non-limiting example, this applies to a vehicle sensor 2, such as a camera, located in the area of the rear windshield. In this case, the reference axis is the vehicle axis.

[0058] In one non-limiting embodiment, the detection plane 20 and the acceleration plane 21 are horizontal. In one non-limiting example, this applies to a building sensor 2 such as a solar collector or photovoltaic sensor.

[0059] It should be noted that without these 20°-30° tilts or inclinations, the detection surface 20 and acceleration surface 21 are not tilted enough so that the obstacle element g2 is naturally pushed outside the detection surface 20 by gravity, especially when stationary.

[0060] When the tilt angle is greater than 30°, the obstacle g2 may be naturally removed by gravity. However, the removal by gravity takes a long time, and during this removal time, otherwise called the dead time, the removal by gravity interferes with or even disables the detection function of the sensor 2. Furthermore, the natural removal by gravity is not very effective, and residues of the obstacle g2 still remain.

[0061] In a first non-limiting embodiment, the detection surface 20 and the acceleration surface 21 do not form part of the sensor 2. The washing system 1 (particularly the washing device 10 and the acceleration device 12) is therefore located away from the sensor 2, and in particular from the surface 20 to be washed. The nozzle 100 deposits droplets g1 on a surface external to the sensor 2. In one non-limiting example, this is the case when the sensor 2 is a vehicle sensor, such as a camera located behind the rear windshield of a vehicle. To avoid obstructing the driver's visibility, the washing system 1 is not positioned directly near the camera 2, but rather far upstream of the camera 2, at a distance called the dead zone. The washing system 1 is then arranged on the outside of the windshield or on a body that is elevated relative to the camera 2. The acceleration surface 21 thus forms part of the windshield or body in this case, and the detection surface 20 forms part of the windshield.

[0062] In a second non-limiting embodiment, the aforementioned detection surface 20 and acceleration surface 21 form part of the sensor 2. The sensor 2 thus comprises the detection surface 20, i.e., the surface to be cleaned, and the acceleration surface 21. The cleaning system 1 (particularly the cleaning device 10 and the acceleration device 12) is therefore located near the surface 20 to be cleaned. The nozzle 100 deposits a droplet g1 on a portion of the surface of the sensor 2. In one non-limiting example, this is the case when the sensor 2 is a building sensor, such as a solar collector or a photovoltaic sensor. In one non-limiting embodiment, the entire surface formed by the detection surface 20 and acceleration surface 21 of the sensor 2 is approximately rectangular. In one non-limiting embodiment, the entire surface is between 100 mm and 1500 mm. In this case, in one non-limiting embodiment, a portion of the acceleration surface 21 may also partially coincide with a portion of the detection surface 20. This means that the droplet g1 of the liquid Lq can be accelerated on a portion of the detection surface 20.

[0063] In a third non-limiting embodiment, the aforementioned detection surface 20 forms part of the sensor 2, and the acceleration surface 21 does not form part of the sensor 2. The sensor 2 therefore comprises the detection surface 20, i.e. the surface to be cleaned, but does not comprise the acceleration surface 21. The cleaning system 1 (in particular the cleaning device 10 and the acceleration device 12) is therefore located in the vicinity of the surface to be cleaned 20. The nozzle 100 deposits droplets g1 on a surface external to the sensor 2.

[0064] As shown in FIGS. 1 to 8, the cleaning device 10 includes a plurality of nozzles 100.

[0065] In a non-limiting embodiment, the cleaning device 10 includes: a perforated bar 101; a support element 102 for said perforated bar 101; a water distributor 103; a protruding element 104 for the perforated bar 101; Further provided are:

[0066] In one non-limiting embodiment, the cleaning device 10 further comprises an attachment element 105 .

[0067] The elements of the cleaning device 10 are described in detail below.

[0068] The nozzle 100 is configured to generate and deposit a droplet g1 of a liquid Lq onto an acceleration surface 21 of the sensor 2, said acceleration surface being located upstream of said detection surface 20.

[0069] In one non-limiting embodiment, the droplet g1 has a volume v0 of 2 μL to 50 μL (microliters). This allows for a droplet g1 that is small enough to limit consumption of the liquid Lq, yet large enough to roll on the acceleration surface 21 and the detection surface 20. The droplet g1 has a sufficient rolling angle.

[0070] In one non-limiting embodiment, the nozzle 100 is configured to deposit the droplets g1 at a pressure of 0.5 bar or less. Thus, the nozzle 100 can operate at a low pressure to control the generation of the droplets g1 and their deposition on the acceleration surface 21. Too much pressure will result in a jet of the liquid Lq rather than the formation of droplets g1 of the liquid Lq.

[0071] In one non-limiting embodiment, the nozzle 100 has a diameter d1 of 0.5 mm to 6 mm (millimeters). Note that if the diameter d1 is 0.5 mm, a droplet g1 of 6 mm can be generated.

[0072] In one non-limiting embodiment, the nozzles 100 are spaced apart such that the deposited droplets g1 form a waterfront w1 (alternatively referred to as a wavefront, shown in FIG. 6). In a variation of this non-limiting embodiment, the nozzles 100 are spaced apart by a distance d2 (shown in FIG. 6) equal to ±10% of the diameter d0 of the droplets g1. This waterfront w1 is a combination of droplets g1 generated after the aforementioned droplets g1 are deposited on the acceleration surface 21, allowing for more effective coverage of the entire surface to be cleaned, i.e., the detection surface 20. Combined with the diameter d0 range of 2 μl and 50 μl, this allows the droplets g1 to coalesce into larger droplets to form the waterfront w1.

[0073] Furthermore, the nozzle 100 is positioned at a distance d3 (shown in FIG. 6) from the acceleration plane 21 that is between 0 and 100% of the diameter d0 of the droplet g1. Therefore, the nozzle 100 is calibrated as a function of the diameter d0 of the droplet g1. The nozzle is close to the acceleration plane 21. This distance d3 is the distance between the bottom of the nozzle 100 and the acceleration plane 21. This causes the droplet g1 to move away from the nozzle 100. At 0%, the droplet g1 is in contact with the nozzle 100 and the acceleration plane 21 at the same time. At 100%, the droplet g1 is no longer in contact with the nozzle 100 when it is in contact with the acceleration plane 21. If the distance d3 is greater than 100% of the diameter d0, the droplet g1 will burst after leaving the nozzle 100 and gaining velocity, breaking up into several smaller droplets on the acceleration plane 21. The droplets slide over the detection surface 20 and entangle the obstruction elements g2, but there are still areas between the droplets where the detection surface 20 is not cleaned. Therefore, marks are still present on the detection surface 20, thus preventing the sensor 2 from performing its detection function.

[0074] The perforated bar 101 includes an orifice (not shown) through which the nozzle 100 is inserted.

[0075] As shown in Figures 7 and 8, in one non-limiting embodiment, the perforated bar 101 and the nozzle 100 form only a single component for sealing. The perforated bar 101 is connected to the nozzle 100 on one side and to the tank 11 on the other side via a connecting tube 106 shown in Figures 7 and 8.

[0076] As shown in Figure 9, the support element 102 for said bar 101 comprises a cavity 1020 into which said bar 101 can be inserted. The cavity 1020 is longitudinal.

[0077] In one non-limiting embodiment, the support element 102 of the aforementioned bar 101 is also configured to receive the accelerator 12. For this purpose, in one non-limiting embodiment, the support element 102 comprises an additional cavity 1021 into which the accelerator 12 can be inserted. This is the case when the accelerator 12 comprises an airflow injection device, as described below. As shown in FIG. 9, in a variant of one non-limiting embodiment, the additional cavity 1021 is located below the cavity 1020 and faces the nozzle 100.

[0078] In one non-limiting embodiment, the support element 102 further comprises a protective cover 1022 configured to protect the connecting tube 106 described above.

[0079] In one non-limiting embodiment, the support element 102 further comprises an orifice 1023 into which the water distributor 103 can be inserted to connect the water distributor 103 to the connecting pipe 106, as shown in Figure 7. This orifice 1023 opens onto the cavity 1020.

[0080] In one non-limiting embodiment, the support element 102 further comprises a holding element 1024 configured to hold the support 3 (shown in FIG. 2) on which the aforementioned cleaning device 10 is placed. In the non-limiting example shown in FIG. 9, said holding element 1024 consists of two holding tabs.

[0081] 7 and 8, the water distributor 103 is configured to distribute the liquid Lq to the nozzles 100. Thus, the bar 101 is connected to the tank 11 via the water distributor 103. In one non-limiting embodiment, the water distributor 103 is connected to the tank 11 via a connecting pipe 106.

[0082] To obtain the waterfront w1 described above, in one non-limiting embodiment, the liquid Lq in the nozzles 100 is distributed homogeneously and continuously for a limited period of time. "Homogeneous" is understood to mean that the distribution of the liquid Lq allows all nozzles 100 to simultaneously generate droplets g1 of the same size. "Continuous" is understood to mean that the distribution of the liquid Lq allows the nozzles 100 to generate droplets g1 one after another. The limited period of time can reduce the consumption of the liquid Lq. In one non-limiting embodiment, the period is 0.5 seconds. This allows the waterfront w1 or a line of droplets g1 to be generated. In one non-limiting embodiment, to have a homogeneous and continuous distribution, the water distributor 103 is arranged between two sets 100a and 100b of nozzles 100 symmetrically distributed on either side of the water distributor 103 (e.g., as shown in Figures 7 and 8). In one non-limiting embodiment, the water distributor 103 is T-shaped. It should be noted that if the water distributor 103 is placed at the end of the bar 101 rather than in the middle, there is a risk that the water distribution will be discontinuous and non-homogeneous. Non-homogeneous is understood to mean a distribution that is not evenly distributed, since the nearest nozzles 100 will receive more liquid Lq than the farthest nozzles 100, which may cause differences in size between the droplets g1 generated.

[0083] In one non-limiting embodiment, to generate a continuous injection of droplets g1, the cleaning system 1 may further include a solenoid valve (not shown) for controlling the opening time of the water dispenser 103. Thus, the period for dispensing water is limited.

[0084] 5 and 6, the protruding elements 104 of the aforementioned bar 101 are configured, in a non-limiting example, to protect the acceleration surface 21 from external aggressions such as dirt, wind, etc. In one non-limiting embodiment, the protruding elements 104 and the support element 102 form only a single component. The protruding elements 104 extend above the nozzle 100.

[0085] As shown in Figure 3, the mounting element 105 is configured to mount the cleaning device 10 to a support 3 (shown in Figure 2) that may form part of the sensor 2 or be separate from the sensor 2. Thus, in one non-limiting example, for a sensor 2 for a vehicle, the support 3 is the body of the vehicle or the windshield of the vehicle. Thus, in one non-limiting example, for a sensor 2 for a building, such as a solar collector or photovoltaic sensor, the support 3 is the structure of said sensor 2. In one non-limiting example, the mounting element 105 is a screw.

[0086] The accelerator 12 of the cleaning system 1 will now be described in detail.

[0087] The acceleration device 12 is configured to accelerate the movement of droplets g1 of the liquid Lq from said acceleration surface 21 to said detection surface 20. This makes it possible, in one non-limiting example, to entrain obstruction elements g2, such as static dirt or static water droplets located on the detection surface 20, and thus to remove them from said detection surface 20. These droplets g1 thus accelerate the flow of obstruction elements g2, which may naturally occur due to gravity, in a manner that quickly clears the detection surface 20, which is the detection surface of the sensor 20, of obstruction elements g2.

[0088] The advantages of such acceleration of the droplet g1 will be explained below.

[0089] Accelerating the droplet g1 reduces the cleaning time of the detection surface 20. This reduces the dead time that may exist when the sensor 2 performs its detection function, a dead time due to an obstruction g2 that interferes with said detection function.

[0090] It should also be noted that the viscosity of the droplet g1 changes with temperature. Viscosity increases in cold weather. By accelerating the droplet g1 rather than allowing it to naturally roll on the acceleration surface 21 and then on the detection surface 20, external factors such as temperature or wind are overcome. Specifically, without acceleration, if the temperature is too low, the droplet g1 will not flow fast enough on the acceleration surface 21 and then on the detection surface 20, and therefore risk not sufficiently entraining the obstacle g2 to remove it from the detection surface 20.

[0091] Furthermore, accelerating the droplet g1 overcomes the surface condition of the detection surface 20. Specifically, if the detection surface 20 is not sufficiently hydrophobic, it becomes difficult for the droplet g1 to naturally roll on the detection surface 20 due to gravity, making it difficult for the droplet g1 to effectively entangle the obstacle element g2.

[0092] Finally, by accelerating the droplet g1, the tilt angle of the detection surface 20 is overcome. Specifically, if the tilt angle is less than 20%, it becomes difficult for the droplet g1 to naturally roll on the detection surface 20 due to gravity, and it becomes difficult for the droplet g1 to effectively entangle the obstacle element g2.

[0093] Thus, the acceleration of droplet g1 allows for providing droplet g1 with sufficient kinetic energy to roll properly on acceleration surface 21 and detection surface 20, and thus effectively engulfing obstacle element g2 so as to remove obstacle element g2 from detection surface 20.

[0094] The accelerator 12 is described according to various non-limiting embodiments below.

[0095] In a first non-limiting embodiment shown in Figures 1 and 6, the acceleration device 12 is an airflow injector. The airflow injector is therefore a fan. An airflow is directed at the droplets g1 to accelerate them. In one non-limiting example, the airflow injector is arranged in an additional cavity 1021 of the support element 102 for the bar 101 described above.

[0096] In a second non-limiting embodiment (not shown), the acceleration device 12 is a device consisting of an electrode grid configured to pass an electric current. The electric current is alternating current. This causes an inchworm motion for the droplet g1, accelerating its movement. The droplet g1 therefore becomes hydrophilic. This electrode grid is integrated into the acceleration surface 21.

[0097] In a third non-limiting embodiment, the accelerator 12 is configured to generate the Leidenfrost effect by heating the acceleration surface 21. The Leidenfrost effect is a phenomenon that induces the heating of a droplet on a hot plate. Thus, instead of violently boiling and vaporizing, the droplet g1 assumes a highly rounded shape and becomes hypermobile. In one non-limiting example, the acceleration surface 21 is heated to more than 160°. The accelerator 12 is positioned in the region of the acceleration surface 21. In one non-limiting example, the accelerator 12 is a flexible substrate including a piezoelectric element. In another non-limiting example, the accelerator 12 is comprised of a thermal resistor.

[0098] In a fourth non-limiting embodiment, the acceleration device 12 is a device configured to synthesize ultrasonic waves propagating in the acceleration surface 21. The device comprises at least one wave transducer acoustically coupled to the acceleration surface 21. This device allows a liquid to be actuated under the action of ultrasonic waves and accelerated on the acceleration surface 21. The liquid takes the form of highly rounded and therefore hypermobile droplets g1. This therefore allows for a simple and effective cleaning of the detection surface 20 as these droplets g1 move across the detection surface. In one non-limiting example, the acceleration device 12 is a device configured to synthesize ultrasonic waves propagating within the acceleration surface 21 and the detection surface 20. The device includes at least one wave transducer acoustically coupled to the acceleration surface 21 and the detection surface 20. The liquid assumes the form of a highly rounded, therefore super-mobile, droplet g1 on the acceleration surface 21. In particular, by actuating the liquid and accelerating it on the acceleration surface 21 under the action of ultrasonic waves, it becomes easier to spread the layer of liquid formed by the liquid onto the detection surface 20. Furthermore, dirty water can be effectively removed from the detection surface. Droplets of dirty liquid that adhere to the detection surface under the action of capillary forces can be easily removed.

[0099] In a fifth non-limiting embodiment, the accelerator 12 is a device made of particles of different polarities. The accelerator 12 is integrated into an acceleration surface 21, i.e., an acceleration surface 21 made of particles of different polarities. Upon contact with the acceleration surface 21, the droplet g1 breaks up. The breakup causes a small rebound of the droplet g1, resulting in the aforementioned acceleration of the droplet g1.

[0100] The cleaning system 1 is therefore configured to implement a method 5 for cleaning the sensing surface 20 of the sensor 2. The cleaning method 5 is illustrated in FIG. E1 indicated by F1(g1, 21, 1(100)) deposits droplets g1 of the liquid Lq on the acceleration plane 21 located upstream of the detection plane 20 described above using a plurality of nozzles 100 of the illustrated cleaning device 10; and E2, denoted F2(g1,21,12), accelerating the movement of said droplet g1 of liquid Lq from said acceleration surface 21 to said detection surface 20 by means of an acceleration device 12.

[0101] It should be understood that the description of the present invention is not limited to the above-described embodiments and fields. Accordingly, in one non-limiting embodiment, the entire surface 22 formed by the detection surface 20 and the acceleration surface 21 is curved. Accordingly, in one non-limiting embodiment, the entire surface 22 is elliptical or circular. Accordingly, in another non-limiting embodiment, the sensor 2 is, in one non-limiting example, a light emitter such as a headlamp. Accordingly, the present specification has provided a non-limiting example of a sensor 2 located behind the rear windshield of a vehicle. However, in another non-limiting embodiment, it should be understood that the washing system 1 can also be applied to a sensor 2 located behind the windshield of a vehicle.

[0102] Thus, the invention as particularly described is The use of the droplet g1 of the liquid Lq in combination with the acceleration of the droplet g1 as described above allows for an effective cleaning of the sensing surface 20 of the sensor 2, If the obstruction element g2 is too small, it makes it possible to effectively replace solutions using only airflow jets, which are ineffective in the case of airflow alone; It is valid regardless of the size of the obstacle element g2, It allows to treat large surfaces contrary to rotational solutions that use centrifugal force to eliminate the obstruction element g2, It makes it possible to avoid having a vibrating component, as opposed to the solution of using ultrasound to eliminate the obstruction element g2, a solution applicable to polymer components, It allows to cope with sensors 2 of the same size as other solutions used, the washing system 1 can be positioned at a distance from the sensor 2, in particular from its detection surface 20, so as to allow a good integration of the washing system 1 in the vehicle, It is a solution that is suitable for vehicle sensors 2 that cannot receive a cleaning system in the vicinity of said sensor 2, such as a camera, but are located behind the rear windshield or windscreen at only a short distance from the sensor 2, and has the advantage that it is a less bulky solution than one or more air flow injection devices that must be used in this case to be able to generate an air flow powerful enough to travel the distance that separates the sensor 2 from the sensor 2 in order to clean it.

Claims

1. A system (1) for cleaning a sensing surface (20) of a sensor (2), comprising: a cleaning device (10) comprising a plurality of nozzles (100) configured to deposit droplets (g1) of a liquid (Lq) onto an acceleration surface (21) located upstream of the detection surface (20); a tank (11) connected to the cleaning device (10) and configured to store the liquid (Lq); a device (12) for accelerating the movement of the droplet (g1) of liquid (Lq) from the acceleration surface (21) to the detection surface (20); A cleaning system (1) comprising:

2. The washing system (1) according to claim 1, wherein the droplet (g1) has a volume (v0) of between 2 μL and 50 μL.

3. 3. A cleaning system (1) according to claim 1 or 2, wherein the liquid (Lq) has a surface tension (γ3) greater than the surface tension (γ1) of the detection surface (20).

4. 3. The cleaning system (1) according to claim 1 or 2, wherein the nozzles (100) are spaced apart from one another such that the droplets (g1) form a waterfront (w1).

5. 3. The cleaning system (1) according to claim 1 or 2, wherein the cleaning device (10) further comprises a perforated bar (101) connected on one side to the nozzle (100) and on another side to the tank (11).

6. 6. The cleaning system (1) according to claim 5, wherein the cleaning device (10) further comprises a support element (102) for the perforated bar (101).

7. The acceleration device (12) an airflow jet, or a device consisting of a grid of electrodes configured to allow an electric current to pass through it; or a device configured to produce the Leidenfrost effect, or a device configured to synthesize ultrasonic waves propagating in said acceleration plane (21); or Devices consisting of particles of different polarities 3. The washing system (1) according to claim 1 or 2, wherein:

8. Assembly comprising a sensing surface (20) of a sensor (2) and a cleaning system (1) according to claim 1 or 2.

9. Assembly according to claim 8, wherein the sensor (2) is an optical sensor.

10. the detection surface (20) and the acceleration surface (21) form part of the sensor (2); or the detection surface (20) and the acceleration surface (21) do not form part of the sensor (2); 9. The assembly of claim 8.

11. 9. The assembly of claim 8, wherein the detection surface (20) and the acceleration surface (21) are coplanar.

12. 9. The assembly of claim 8, wherein a portion of the detection surface (20) partially coincides with a portion of the acceleration surface (21).

13. A method (5) for cleaning a sensing surface (20) of a sensor (2) for a vehicle (3), comprising: depositing droplets (g1) of a liquid (Lq) by a plurality of nozzles (100) of a cleaning device (10) on an acceleration surface (21) of the sensor (2) located upstream of the detection surface (20); accelerating the movement of the droplet (g1) of liquid (Lq) from the acceleration surface (21) to the detection surface (20) by an acceleration device (12); A cleaning method (5), comprising:

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