FR3143503A1 - Cleaning device for glass surface - Google Patents

Abstract

The invention proposes a cleaning device for a glass surface of a detection device fitted to a vehicle, comprising a nozzle supplied with liquid cleaning product, and having a spray head diffusing the liquid in the form of a jet, said head d sprinkler having a closed end. This sprinkler head comprises at least one sprinkler wall provided with at least one hole through which a straight jet emerges. Figure for abstract: Figure 3

Description

Glass surface cleaning device Technical field of the invention

The present invention relates to the field of driving assistance devices and, more particularly, to the field of optical detection systems used for this purpose.

The invention relates more particularly to cleaning devices configured for cleaning an optical sensor of such an optical detection system.

Technical background

An optical detection system is any system comprising optical sensors such as cameras, laser sensors or other sensors based on the emission and/or detection of light in the spectrum visible or invisible to humans, in particular infrared.

Such optical detection systems are being fitted to an increasing number of motor vehicles either to assist the driver of the vehicle in certain driving situations, one of which is well-known, parking assistance, or to make the driving of the vehicle autonomous or partly autonomous.

The driving assistance devices may comprise detection devices that may take the form, for example, of sensors intended to evaluate an environment outside the motor vehicle, or the form of a camera intended to offer the driver visibility of an environment outside the motor vehicle, visually inaccessible from the driver's seat. Such detection devices then comprise at least one glazed surface positioned within the vehicle such that it is capable of capturing the environment outside the motor vehicle, in a desired area.

For autonomy and/or driving assistance to be as effective as possible, the data provided by the sensor must be of the best possible quality, and it is therefore essential to have a clean glass surface to carry out these data acquisitions.

To do this, a cleaning device is arranged in the vicinity of an optical detection device (for example the lens of a camera) in order to be able to project, on demand, a fluid so as to remove any dirt deposited on the glass surface of the detection device. This may be dust or insects for example.

This cleaning is essential to provide optimal visibility to the sensor or the user of the motor vehicle.

As is known, such a cleaning device comprises a nozzle hydraulically connected to a fluid storage tank. The fluid is ejected from the nozzle via a distribution orifice, towards the glass surface to be cleaned. The nozzle diffuses the cleaning liquid in the form of a jet.

During operation, the free end of the nozzle protrudes from the bodywork and is therefore visible from outside the vehicle.

It is known to use nozzles with a relatively wide jet profile, such as a flat jet or conical jet, which provide a large radius of action, sweep the entire width of the glass, and therefore clean a large surface, in this case the entire glass surface of the sensor to be cleaned, with a single distribution orifice.

The flat jet consists of a jet that strikes orthogonally or obliquely on a deflection surface that allows the jet to be reflected flat and with a large width, like a fan.

The cone jet escapes from the cleaning device with a solid or hollow cone shape.

It is therefore possible to clean the entire surface in question using a single jet, and a single nozzle. Using a single nozzle allows you to remain discreet, and to avoid having too many visible parts protruding from the vehicle bodywork.

The disadvantage of this type of nozzle with flat or conical jet is the use of too large a volume of cleaning liquid. In addition, the width of the jet required to sweep the entire glass surface to be cleaned leads to a reduction in the impact pressure, which results in a reduction in cleaning efficiency.

In the current context, where we want to reduce the amount of cleaning fluid used, so as to carry less volume of liquid in the vehicle, and so as not to waste the liquid on board, a problem arises.

The aim of the present invention is therefore to provide a cleaning device which can remain discreet and compact and which uses a smaller quantity of cleaning liquid, whilst offering high cleaning performance.

The invention therefore relates to a cleaning device for a glass surface of a detection device equipping a vehicle, comprising a nozzle supplied with liquid cleaning product, and having a spray head diffusing the liquid in the form of a jet, said spray head having a closed end.

The invention is mainly characterized in that said spray head comprises at least one spray wall provided with at least one hole through which a straight jet emerges.

The detection device and the cleaning device may be those of a driving assistance device housed within a motor vehicle. For example, the detection device may be a camera or a sensor for increasing the visibility of a user of the motor vehicle on the external environment of said vehicle. Each camera or each sensor has at least one glazed surface exposed to the external environment. Thanks to its glazed surface, the detection device captures data from the external environment of the motor vehicle. The cleaning device allows the cleaning of the glazed surface of the detection device such that said glazed surface is freed from external pollutants and thus its optical performance is not degraded.

The cleaning device according to the invention cleans the glass surface with a straight jet. This means that the jet that impacts a surface forms a point on the surface. This point has a very small cross-section, unlike flat and conical jets which have very wide cross-sections.

The idea behind the invention is to use this form of straight jet, also called "straight point", to have a stronger point of impact on the glass surface, so as to be able to better detach stubborn dirt, and this for a constant flow rate through the nozzle. Indeed, the fluid speed is higher than that of the prior art, because the passage section of the hole is smaller, for the same flow rate. The cleaning efficiency is thus improved.

The number of holes should be defined according to the surface to be cleaned.

Each hole forms a straight jet at the outlet. All of these straight jets cover the entire glass surface to be cleaned.

By using one or more holes with a straight jet profile, the amount of liquid cleaning product to be used is drastically reduced, while retaining a conventional cleaning device, in particular with a pump, a valve, a fluid circulation channel inside the nozzle, etc. Only the spray head differs. It is more compact because the holes are very small compared to the prior art. The part protruding from the vehicle body is thus minimal.

• le trou présente un diamètre compris entre 50 et 250µm. Pour comparaison, un trou d’un jet conique présente un diamètre compris entre 0,3 et 1mm.
• la paroi d’aspersion présente une pluralité de trous répartis spatialement de façon à ce que leurs jets recouvrent la majeure partie de la surface vitrée à nettoyer située en vis-à-vis.
• la paroi d’aspersion présente une pluralité de trous répartis uniformément.
• tous les trous présentent une même section.
• la paroi d’aspersion est orientée perpendiculairement ou obliquement à l’extrémité fermée.
• l’extrémité fermée consiste en une paroi d’aspersion.
• le trou est cylindrique.
• la paroi d’aspersion est plane.
• la paroi d’aspersion est incurvée.
• tous les trous sont orientés perpendiculairement à la paroi d’aspersion, les jets droits en découlant étant perpendiculaires à la paroi d’aspersion.
• tous les trous sont orientés obliquement à la paroi d’aspersion, les jets droits en découlant étant obliques à la paroi d’aspersion.
• une partie des trous est orientée perpendiculairement à la paroi d’aspersion, et l’autre partie des trous est orientée obliquement à la paroi d’aspersion.

According to the different embodiments of the invention, which may be taken together or separately:

• The hole has a diameter between 50 and 250µm. For comparison, a hole in a conical jet has a diameter between 0.3 and 1mm.
• the spray wall has a plurality of holes distributed spatially so that their jets cover the majority of the glass surface to be cleaned located opposite.
• The sprinkler wall has a plurality of evenly distributed holes.
• all holes have the same section.
• the spray wall is oriented perpendicular or obliquely to the closed end.
• the closed end consists of a sprinkler wall.
• the hole is cylindrical.
• the sprinkler wall is flat.
• the sprinkler wall is curved.
• all holes are oriented perpendicular to the spray wall, the resulting straight jets being perpendicular to the spray wall.
• all holes are oriented obliquely to the spray wall, the straight jets resulting from them being oblique to the spray wall.
• one part of the holes is oriented perpendicular to the sprinkler wall, and the other part of the holes is oriented obliquely to the sprinkler wall.

Brief description of the figures

Other features and advantages of the invention will become apparent upon reading the detailed description which follows, for the understanding of which reference will be made to the appended drawings in which:

There represents the projection of several different jet shapes;

There is a perspective view of a nozzle according to the prior art diffusing a flat jet;

There is a perspective view of a sprinkler according to the invention with a first spray head configuration;

There is a perspective view of a sprinkler according to the invention with a second spray head configuration;

There is a perspective view of a sprinkler according to the invention with a ^3rd spray head configuration;

There represents the projection of a straight jet from a nozzle according to the invention;

There is a sectional view of an example of the spray head of a nozzle according to one of Figures 3 to 5;

There is a sectional view of another example of the spray head of a nozzle according to one of Figures 3 to 5;

There is a detailed view of the holes present on a sprinkler head of a nozzle according to the invention;

There is a perspective view of a sprinkler according to the invention with a fourth spray head configuration;

There is a sectional view of an example of the spray head of a sprinkler according to the ;

There is a perspective view of a sprinkler according to the invention with a fifth spray head configuration;

There is a perspective view of a sprinkler according to the invention with a sixth spray head configuration;

There consists of a graph comparing the performance of a prior art nozzle with a nozzle according to the invention.

Detailed description of the invention

In the remainder of the description, elements having an identical structure or similar functions will be designated by the same references.

By convention, the "axial" direction corresponds to that of the main extension of the nozzle, illustrated by the X axis on the , and the "radial" direction is orthogonal to the axial direction. For example, the Y axis is orthogonal to the X axis and thus shows a radial direction.

In the detailed description of the figures which follow, the terms “upper” and “lower” or “top” and “bottom” will be used in a non-limiting manner in reference to the axial direction.

There represents the projection of several different jet shapes.

In this case, Figures 1a and 1b show the projection of a flat jet. In Figure 1a, the flat jet has a convex distribution, while in Figure 1b, the flat jet has a uniform distribution.

Figures 1c, 1d, 1e show the projection of a conical jet. This conical jet has a convex distribution in Figure 1c, a uniform distribution in Figure 1d, and a concave distribution in Figure 1e.

These types of flat and conical jets are used in prior art cleaning devices, to clean the glass surface of various optical sensors belonging to detection systems installed on motor vehicles.

Such a prior art cleaning device is illustrated in . In this case, it is a nozzle 1 hydraulically connected to a cleaning product supply source.

The cleaning product is a fluid preferably in liquid form, such as windshield washer fluid. In general, a pump takes the liquid product from the supply source (in this case a tank) and returns it, via one or more valves, to the nozzle 1 which then diffuses the liquid product in the form of a jet towards the optical sensor located nearby.

The nozzle 1 has a first end 6 corresponding to a hydraulic connection, and a second free end corresponding to a spray head 2 through which the liquid product is expelled. Here, the liquid product is sprayed in the form of a flat jet with a uniform distribution.

The nozzle 1 extends along a central axis X, from the first end 6 to the spray head 2. The nozzle 1 has an internal channel inside which the liquid product circulates from the first end 6 to the spray head 2.

The spray head 2 is closed and has an orifice for distributing the liquid product to diffuse it in the form of a jet, after it has been reflected on a deflection surface located inside the head 2, so as to obtain a flat jet.

For flat and conical jets, the single distribution orifice must be large enough to provide a wide projection at the outlet. For conical jets, the distribution orifice must have a particular shape, for example with a first cylindrical section followed by a second conical section flared outwards. It is also possible to provide a swirl chamber inside the spray head opening onto the distribution orifice. It is also possible to provide a nozzle in the spray head, with an anvil arranged inside, so as to form a jet with a certain shape at the outlet. There are many technical solutions.

These flat and conical jets have the advantage of being able to diffuse the product with a relatively wide spectrum, and therefore of covering at least the entire width of the glass surfaces of the sensors.

However, the pressure of the liquid product on the glass surface at the time of impact is sometimes not sufficient to remove the most stubborn stains.

Hence the use of the nozzles 1 according to the invention as illustrated in Figures 3 to 13. In these figures, the nozzle 1 used has all the technical characteristics of the nozzle 1 of the prior art, except for the spray head 2.

The spray head 2 is still closed by means of a closed end 4, but it is simplified to the extreme. In particular, it does not have an internal deflection surface, nor a nozzle, nor anvil, nor a distribution orifice with a complex shape or a large diameter.

The spray head 2 according to the invention comprises at least one spray wall 3 provided with at least one hole 5 through which a straight jet emerges.

This is a simple 5 hole, with a uniform section.

The jet is straight, meaning that its projection corresponds only to a point, as illustrated in .

Such a straight jet cannot sweep the entire width of a glass surface of a detection device, unless the glass surface is very small. However, with such a straight jet, the pressure is greater at the point of impact, compared to a cone or flat jet. Thus, this type of straight jet can better clean dirty surfaces at the precise location where it impacts.

The spray wall 3 is oriented towards the detection device to be cleaned located near the nozzle 1.

According to the invention, each hole 5 has a diameter of between 50 and 250 µm, which is very small compared to the diameter of the dispensing orifices of the prior art. This also makes it possible to be precise at the point of impact on the surface to be cleaned.

To cover a larger surface area, several holes 5 may be provided in the spray wall 3, in order to distribute the jets over the surface to be cleaned. Preferably, the holes 5 are spatially distributed on the spray wall 3 so that their jets cover the majority of the glass surface to be cleaned located opposite.

The number of holes 5 to be provided is calculated based on the extent of the surface to be cleaned nearby.

Preferably, the holes 5 are so small that the total of their sections remains less than the section of a distribution orifice according to the prior art.

Thus, for the same flow rate passing through the nozzle 1, the pressure of the jet on the glass surface will be significantly greater with a spray head 2 according to the invention than with a spray head 2 according to the prior art.

This is illustrated in particular in , where the curve with the small circles corresponds to the use of a nozzle 1 according to the prior art, and the curve with the small diamonds corresponds to the use of a nozzle 1 according to the invention. For the same flow rate (in ml/s), the pressure exerted on the surface to be cleaned by the jet leaving a nozzle 1 according to the prior art is much lower than the pressure exerted on the same surface to be cleaned by the jet leaving a nozzle 1 according to the invention.

In fact, the smaller the hole passage section, the more the fluid speed increases for the same volume flow rate. Thanks to this higher fluid speed (i.e. the speed of interaction with the surface), cleaning efficiency is improved.

With these small holes, it follows that the consumption of liquid product necessary for cleaning is lower compared to the prior art. Indeed, the consumption drops by at least 40%, and up to 60% with a nozzle according to the invention compared to a nozzle according to the prior art, and this while maintaining the same percentage of coverage of the cleaned surface, as shown in the table below.

Std nozzle corresponds to a nozzle according to the prior art.

New nozzle corresponds to a nozzle according to the invention.

The first column specifies the percentage of surface covered by the jets.

The second column specifies the windshield washer fluid consumption in ml/s.

The third column compares the liquid consumption between the two types of nozzle, and gives the percentage of liquid used with the nozzle according to the invention. The reduction is approximately 60%.

The fourth column specifies the fluid velocity at the outlet of the orifice/hole.

The fifth column compares the fluid velocity between the two types of nozzle, and gives the percentage of additional velocity with the nozzle according to the invention. There is an increase in velocity of approximately 17% to 20%.

According to a first configuration of the sprinkler head 2 shown in , the spray wall 3 has a plurality of holes 5 distributed uniformly. In this case, there are 36 holes 5 distributed over six columns oriented perpendicular to the X axis, each column comprising six holes 5. Each hole 5 has a diameter of 100 µm.

According to a second configuration of the sprinkler head 2 shown in , the spray wall 3 has four holes 5 aligned on a single column oriented perpendicular to the X axis. Each hole 5 has a diameter of 200 µm.

According to a third configuration of the sprinkler head 2 shown in , the sprinkler wall 3 has seven holes 5 aligned on two columns oriented perpendicular to the X axis. The holes 5 are staggered from one column to the other.

Preferably, whatever the configuration, the holes 5 have the same section.

However, within the framework of the present invention, it would be possible to provide that the holes 5 do not have the same section depending on their location on the spray wall 3.

We understand that there can be a multitude of possible configurations, depending on the number of holes 5, their section, and their positioning on the spray wall 3.

It will be noted that the holes 5 are preferably arranged in the vicinity of the closed end 4 of the spray head 2. Indeed, only the spray head 2 protrudes from the body of the vehicle. The closer the holes 5 are to the closed end 4, the more it will be possible to hide a portion of the spray head 2 in the body. This is valid for the nozzles fixed in the body. The nozzles of the present invention can also be removable, in particular movable by translation, or even telescopic in order to disappear under the hood.

In Figures 3 to 5, the spray walls are oriented perpendicular to the closed end 4. However, within the framework of the present invention, it would be possible to provide spray walls oriented obliquely to the closed end 4, that is to say inclined relative to the axis X. The orientation of the spray wall 3 depends in particular on its position relative to the surface to be cleaned.

In the 3 examples shown in Figures 3 to 5, the sprinkler head 2 has a rectangular section. It is therefore formed of four side walls and an end wall.

Depending on the relative positioning between the nozzle 1 and the glass surface to be cleaned of the detection device, the holes 5 will be made on one of these five walls. Indeed, it is possible to consider making holes 5 on the end wall if this is more practical for the integration of the nozzle 1 relative to the detection device within the bodywork. Thus the end wall can also correspond to a spray wall 3.

It is also possible to envisage making holes 5 on several walls of the same nozzle 1, in order to be able to clean simultaneously or alternately several glass surfaces belonging to several detection devices which are located near this nozzle 1. In this case, the spray head 2 has several spray walls 3.

It is possible to consider having several channels inside the nozzle 1 in order to be able to send liquid selectively to one or the other spray wall 3 depending on the sensor to be cleaned nearby.

Figures 7 and 8 show a sectional view of these spray heads 2 with rectangular section. In these sectional views, some holes 5 are shown through which liquid product escapes in the form of a straight jet.

Generally, in all of the configurations shown in Figures 3 through 13, the holes 5 are cylindrical, or nearly cylindrical. In most manufacturing processes, the holes are nearly cylindrical, but are slightly flared in a cone shape.

In the figures shown, the cylindrical holes have a circular section at the outlet.

However, within the scope of the present invention, the cylindrical holes could have a square, or rectangular, or other section.

It will be noted that on the holes 5 are oriented perpendicular to the spray wall 3.

On the , the two central holes 5 are oriented perpendicular to the spray wall 3, while the two lateral holes 5 are oriented obliquely to the spray wall 3.

When the holes 5 are oriented perpendicular to the spray wall 3, the straight jets resulting from them are perpendicular to the spray wall 3.

When the holes 5 are oriented obliquely to the spray wall 3, the straight jets resulting from them are oblique to the spray wall 3.

Depending on the case, all the holes 5 can be oriented perpendicular to the spray wall 3, or only some, or all the holes 5 can be oriented obliquely to the spray wall 3, or only some.

The 5 obliquely oriented holes can be oriented inwards as on the (i.e. towards the Y axis), or outwards as in the (i.e. away from the Y axis), or even backwards as illustrated in the (i.e. towards the first end 6 of the nozzle 1), or even forwards (i.e. towards the second end 4 of the nozzle 1), and this in combination.

The angles are chosen according to the area to be touched with the jet on the surface to be cleaned.

There shows an enlarged view of a spray wall 3 with a plurality of holes 5 of cylindrical section, each hole 5 having a specific orientation, defined according to the surface to be cleaned located nearby, so as to properly direct the jets towards precise locations on the surface.

In figures 3 to 5, and 7 to 8, the spray wall 3 is flat.

However, the spray wall 3 could be curved, as illustrated in Figures 10 to 13.

In particular on the , showing a sectional view of part of the section of the sprinkler head 2 of the , we can clearly see the curved shape of the sprinkler wall 3 in which the holes 5 are made.

Whether the spray wall 3 is flat or curved, the angular orientation of the holes is chosen as explained previously, obliquely or perpendicularly, depending on the position and extent of the target surface to be cleaned, the objective being to have a high coverage rate of the surface to be cleaned.

Other shapes and other sections of spray heads may fall within the scope of the present invention, provided that the holes 5 allow straight jets to be projected which reach the surface to be cleaned of the detection device.

The sprinkler heads can be advantageously obtained by additive manufacturing in order to obtain holes of very small section, rather than by drilling them.

That said, any other manufacturing technique can be envisaged within the framework of the present invention.

The configurations shown in the cited figures are only possible examples, in no way limiting, of the invention which on the contrary encompasses the variants of shapes and designs within the reach of those skilled in the art.

Claims (13)

Cleaning device for a glass surface of a detection device equipping a vehicle, comprising a nozzle (1) supplied with liquid cleaning product, and having a spray head (2) diffusing the liquid in the form of a jet, said spray head (2) having a closed end (4),
wherein said spray head (2) comprises at least one spray wall (3) provided with at least one hole (5) through which a straight jet emerges. Device according to the preceding claim, in which the hole (5) has a diameter of between 50 and 250 µm. Device according to one of the preceding claims, in which the spray wall (3) has a plurality of holes (5) distributed spatially so that their jets cover the majority of the glass surface to be cleaned located opposite. Device according to one of the preceding claims, in which the spray wall (3) has a plurality of uniformly distributed holes (5). Device according to one of the preceding claims, in which all the holes (5) have the same section. Device according to one of the preceding claims, in which the spray wall (3) is oriented perpendicular or obliquely to the closed end (4). Device according to one of claims 1 to 5, in which the closed end (4) consists of a spray wall (3). Device according to one of the preceding claims, in which the hole (5) is cylindrical. Device according to one of the preceding claims, in which the spray wall (3) is flat. Device according to one of claims 1 to 8, in which the spray wall (3) is curved. Device according to one of the preceding claims, in which all the holes (5) are oriented perpendicular to the spray wall (3), the straight jets resulting therefrom being perpendicular to the spray wall (3). Device according to one of claims 1 to 10, in which all the holes (5) are oriented obliquely to the spray wall (3), the straight jets resulting therefrom being oblique to the spray wall (3). Device according to one of claims 1 to 10, in which a part of the holes (5) is oriented perpendicular to the spray wall (3), and the other part of the holes (5) is oriented obliquely to the spray wall (3).