FR3074753A1 - METHOD FOR CONTROLLING A WIPER SYSTEM OF A HYDROPHOBIC VEHICLE GLASS, AND WIPING SYSTEM OF SUCH A GLASS - Google Patents

Abstract

The invention proposes a method for controlling a system for wiping the outer surface of a window (10) of a motor vehicle having undergone at least one hydrophobic treatment, which system comprises a drive arm (31) of a wiper blade (30) which cooperates with the window (10), and a sensor for measuring a parameter making it possible to estimate the degree of hydrophobicity of the outer surface (11) of the window (10) , and a scan speed control circuit (60) that changes the scan rate according to changes in said parameter. According to the method, the degree of hydrophobicity of the outer surface (11) of the pane (10) is estimated by the control circuit (60) as a function of a parameter representative of the coefficient of friction between the wiper blade and the wiper blade. ice (30) and the surface of the window (10).

Description

Method for controlling a system for wiping a hydrophobic glass of a vehicle, and system for wiping such a glass

TECHNICAL FIELD OF THE INVENTION

The invention relates to a method for controlling a system for wiping an exterior surface of a motor vehicle window having undergone at least one hydrophobic treatment.

The invention also provides a system for wiping a surface of a motor vehicle window, this system comprising at least one drive arm in sweeping of a wiper blade which cooperates with an external surface d 'a motor vehicle window having undergone at least one hydrophobic treatment.

TECHNICAL BACKGROUND OF THE INVENTION

Motor vehicles are commonly equipped with wiping and washing systems to ensure wiping and washing of the exterior surface of a motor vehicle window, and in particular of a motor vehicle windshield in order to prevent the the driver's vision of his environment is not disturbed. Such a system generally comprises two wiper blades each having a wiper blade which scrapes the outer surface of the windshield so as to remove the water present on this surface.

In order to wash the windshield, in particular in the absence of rain, such systems are equipped with at least a first reservoir containing a windshield washer fluid, called the first liquid, with a system of pipes connecting this reservoir to orifices through which the first liquid can be ejected and / or projected onto the windshield, and a pump capable of circulating the first liquid in the pipe system until it is expelled through the orifices on the windshield.

In order to improve the quality of washing and wiping, especially in the event of significant soiling of the windshield, and / or to add other functions to the system such as, for example, a defrosting function for the windshield, may provide a second reservoir containing an active liquid, said second liquid, having specific cleaning properties and / or defrosting properties.

The two tanks can each have their pump but are connected to the same system of pipes bringing the first and second liquids to the orifices through which they are ejected on the windshield. So, when we want to switch from the projection of one of the liquids on the windshield to the projection of the other of the liquids, we deactivate the pump that was working and we activate the other pump.

Furthermore, techniques and means are known which make the exterior surface of the windows of motor vehicles hydrophobic.

Hydrophobic treatment allows the driver to avoid using his wipers above a vehicle speed generally estimated at 70 km / h. Above 70km / h the breath of air on the surface of the windshield manages to entrain and eject the drops of water, this due to the weak adhesion between the water and the glass when the glass surface has underwent hydrophobic treatment.

In the present application, the term “hydrophobic liquid” means a liquid which is capable of rendering a surface hydrophobic after spreading, or even drying, the liquid on this surface.

This involves using liquid products with hydrophobic characteristics, products that will be called hydrophobic treatment products, or even hydrophobic treatments. It is known to carry out a hydrophobic treatment on a window of a motor vehicle.

It is for example known to apply this type of treatment by hand using a sponge or a cloth provided for this purpose, as described and shown in patent application US-A12014 / 272148. This application describes a method of applying a hydrophobic product by spraying with a spray or with a damp cloth.

It has also already been proposed to carry out a hydrophobic treatment by implementing a method of applying hydrophobic treatment to a window of a vehicle effectively and without requiring the intervention of a person.

It has for example been proposed to use a system of the type mentioned above in which the second liquid is a hydrophobic liquid, and which comprises at least one of the steps consisting in spraying hydrophobic liquid on the glass by means of the piping systems and pump, and spreading hydrophobic liquid on the glass by means of at least one wiper blade.

Vehicle equipment can thus be used to spray hydrophobic liquid on a window of the vehicle or to spread hydrophobic liquid on the window, or even to do both. Thus, the application and spreading of the hydrophobic product on the glass can take place without manual intervention by the user, who can simply be content to control the process remotely.

This remote control can be carried out from the dashboard of the vehicle or even remotely, for example by means of an application of a mobile phone or a tablet.

Unlike the manual application technique, such a method makes it possible to regularly renew the hydrophobic treatment of the vehicle window without requiring manual work from a person.

However, whatever the technique used to apply and / or renew the hydrophobic treatment, the use of hydrophobic treatment requires taking certain phenomena into account.

In particular, the coefficient of friction between the rubber of the wiper blades of the wiper blades and the hydrophobic treatment is so great that, at low wiping speed, vibrations occur, also known as the effect. stick-slip.

There is no known solution to this problem, except by increasing the scanning speed, but this requires determining the state or degree of hydrophobicity of the surface to be wiped.

In addition, the hydrophobic treatment degrades over time, and it is generally estimated that around four months after the treatment, the hydrophobic treatment has disappeared and / or is no longer effective.

Solutions to this problem are known, which consist in particular in renewing the hydrophobic treatment by automatically recharging the outer surface of the windshield by spreading a hydrophobic liquid thereon, for example by using the known techniques mentioned above.

But here again, to automate or systematize such a renewal, it is necessary to determine the state or degree of hydrophobia of the surface to be wiped.

Thus, whatever the technique used to apply and / or renew the hydrophobic treatment, no method or device is known allowing the user to take into account the presence of a hydrophobic treatment, nor the state or quality of this coating - in particular its wear - to control the wiping system to ensure sufficient quality of wiping, in the best possible comfort.

The invention aims to provide a solution to these problems.

BRIEF SUMMARY OF THE INVENTION

The invention provides a method for controlling a system for wiping an exterior surface of a window of a motor vehicle having undergone at least one hydrophobic treatment, this system comprising at least one drive arm in scanning of a Wiper blade which cooperates with the exterior surface of the window, characterized in that it consists in varying the scanning speed of the drive arm as a function of the degree of hydrophobicity of the exterior surface of the window.

According to other characteristics of the process:

- the method consists in estimating the degree of hydrophobia as a function of a parameter representative of the coefficient of friction between the wiper blade and the surface of the window;

- It consists in modifying the scanning speed when said parameter reaches a determined threshold value representative of a determined threshold value of the degree of hydrophobicity of the exterior surface of the window;

- It consists in increasing the scanning speed when said parameter becomes equal to or greater than a determined threshold value;

- It consists in reducing the scanning speed when said parameter becomes lower than a determined threshold value;

- The method includes a step of renewing the hydrophobic treatment when said parameter becomes less than a determined threshold value;

the step of renewing the hydrophobic treatment includes a step of alerting the user of the vehicle with a view to renewing the hydrophobic treatment;

- The step of renewing the hydrophobic treatment consists in spraying hydrophobic liquid on the exterior surface of the glass and in spreading hydrophobic liquid on the glass by means of a wiper blade;

the wiping system comprises an electric motor for driving the driving arm, and the method is characterized in that said parameter is the temperature and / or the supply voltage of the electric motor, and / or the value of the mechanical torque produced by the drive motor during sweeping;

- The threshold value of the coefficient of friction between the wiper blade and the surface of the window is greater than 0.5, preferably between 0.5 and 0.7, preferably equal to 0.6;

the wiper blade of the wiping system of the wiping system comprises a wiping blade, and the method is characterized in that said parameter is representative of the coefficient of friction between the wiping blade and the surface of the glass.

The invention also provides a system for wiping a surface of a motor vehicle window, this system comprising at least one drive arm in sweeping of a wiper blade which cooperates with an external surface d '' a motor vehicle window having undergone at least one hydrophobic treatment, characterized in that it comprises:

- a sensor for measuring a parameter making it possible to estimate the degree of hydrophobia of the exterior surface of the glass;

- a control circuit of the sweep speed of the drive arm which modifies the sweep speed as a function of variations of said parameter.

According to other characteristics of the system:

- the degree of hydrophobicity of the exterior surface of the window is estimated by the control circuit as a function of a parameter representative of the coefficient of friction between the wiper blade and the surface of the window;

- the system comprises at least one reservoir containing a hydrophobic liquid, a system of pipes connecting this reservoir to orifices through which the hydrophobic liquid is sprayed in the direction of the exterior surface of the window, a pump system intended to circulate the liquid in the piping system, and at least one wiper blade on the exterior surface of the glass capable of spreading hydrophobic liquid on the exterior surface of the glass, and in that the hydrophobic liquid is projected towards the exterior surface glass when said parameter becomes less than a determined threshold value;

- It includes means capable of triggering an alert intended for a user of the vehicle with a view to renewing the hydrophobic treatment of the exterior surface of the window, when said parameter becomes less than a determined threshold value;

- the scanning speed is modified by the control circuit when said parameter reaches a determined threshold value representative of a determined threshold value of the degree of hydrophobicity of the exterior surface of the window;

- the control circuit increases the scanning speed when the coefficient of friction becomes equal to or greater than a determined threshold value;

- the control circuit reduces the scanning speed when the friction coefficient becomes lower than a determined threshold value;

the system comprises an electric motor for driving the drive arm, and e the parameter is the temperature and / or the supply voltage of the electric motor and / or the value of the mechanical torque produced by the motor for driving scanning course;

the threshold value is greater than 0.5, preferably between 0.5 and 0.7, preferably equal to 0.6;

- the wiper blade has a wiper blade, and the coefficient of friction is the coefficient of friction between the wiper blade and the surface of the window.

BRIEF DESCRIPTION OF THE FIGURES

Other characteristics and advantages of the invention will appear during the reading of the detailed description which will follow for the understanding of which reference will be made to the appended drawings in which:

- Figure 1 is a schematic view of a washing and wiping system of a motor vehicle windshield allowing the implementation of a method according to the invention;

- Figures 2 to 4 are diagrams used in particular to illustrate the variations in the coefficient of friction of a hydrophobic coating over time and certain steps in the implementation of the method.

DETAILED DESCRIPTION OF THE FIGURES

In the following description, elements having an identical structure or analogous functions will be designated by the same references.

FIG. 1 shows a system for wiping and washing 1 of a vehicle windshield 10.

Such a system comprises an assembly for washing and maintaining the outer surface 11 of the windshield 10 which comprises a first reservoir 2 containing a first fluid and a second reservoir 3 comprising a second fluid. The first fluid is for example a windshield washer fluid.

The second fluid is a known hydrophobic liquid, that is to say a liquid immiscible with water. This involves using such a liquid to make the exterior surface of a window or of a vehicle body hydrophobic.

Among hydrophobic liquids, it is possible, for example, to use mainly chemical compounds of the silicone family, and more specifically PDMS PolydDiMethylSiloxane with hydroxyl termination.

The washing device 1 also comprises a system of pipes 5 connecting the first tank 2 and the second tank 3 to orifices 15 through which the first fluid and / or the second fluid are ejected onto the windshield 10. It further comprises a pump system 20 intended to circulate the first fluid and / or the second fluid in the piping system 5 until ejection through the orifices 15.

The pump system 20 here comprises two independent pumps 21, 22. A first pump 21 is associated with the first reservoir 2 and is intended to circulate the first windshield washer fluid in the pipe system 5 and a second pump 22 is associated with the second reservoir 3 and is intended to circulate second hydrophobic fluid in the piping system 5.

The wiping system comprises at least one wiper blade 30 which is mounted on a drive arm 31 and which is able to move on the windshield 10 between a low position PB and a high position PH.

Each wiper blade 30 comprises in particular a wiper blade 29 which cooperates with the outer surface of the window to be wiped, here with the outer surface 11 of the windshield 10.

The washing device 1 of FIG. 1 comprises two wiper blades 30. The aforementioned holes 15 are for example located on the wiper blades 30. They can also be located on the arm 31 and / or on the means for connecting the broom to the arm. As a variant, the orifices 15 could be located elsewhere, and for example on the hood of the vehicle.

The orifices 15 may be arranged so as to project the first fluid and / or the second fluid towards the top of the wiper blades 30, that is to say towards the top of the windshield 1 0.

The orifices 15 may be arranged so as to project first fluid and / or second fluid down the wiper blades 30, that is to say down the windshield 1 0.

The orifices 15 are for example arranged in the form of ramps, that is to say one or more alignments of successive orifices. Each wiper blade 30 may for example comprise at least one ramp.

The or each ramp of a brush 30 can be supplied with fluid via one or two pipes of the pipe system 5. A ramp can for example be connected to two pipes supplying the brush with first and second fluids , respectively. As a variant, a ramp can be connected to a single supply line for the brush in first and second fluids, the same pipe therefore serving to supply the brush with the two fluids, in a sequenced manner.

The washing device 1 also comprises a motor 40 intended to drive the wiper blades 30 between their low positions PB and their respective high positions PH.

Each wiper blade can also be driven by an associated drive motor, which acts on the drive arm 31 of the wiper blade, the two drive motors then being controlled and controlled like the motor. single and common 40 shown here.

The drive motor (s) may or may not be of the reversible type.

The washing device 1 also comprises at least one sensor 50. It is located here on an upper part of the windshield, in the center of the latter. It is in particular located at the level of a zone of the windscreen 10 swept by only one of the two wiper blades 30. The sensor 50 is for example a rain sensor, an opacity sensor of the windscreen and / or a light sensor.

The washing device 1 further comprises an electronic unit 60 comprising in particular different circuits and / or programs capable of analyzing different data and parameters, including the data coming from the sensor 50, for controlling the motor 40 for driving the wiper blades. ice 30 and activation of the pump system 20, the first and second pumps 21, 22 being able in particular to be controlled independently.

As illustrated diagrammatically in FIG. 1, the electronic control unit 60 receives different information and data from each drive motor which it controls such as in particular and for example the temperature, the intensity of the supply current , the voltage of the supply current, which in particular make it possible to deduce therefrom the torque supplied by each motor in operation, that is to say the mechanical torque produced by the motor and which is necessary to obtain the movement of the wiper blades - windshield wiping glass.

As a variant, each drive motor 40 can be equipped with a component directly supplying a value of the measured torque.

The electronic control unit uses at least one management or control program or software which, from the various parameters, data and information supplied to it, generate commands for controlling and controlling the drive motors and the pump set 20.

The torque supplied by the motor during sweeping operation is representative of the value of the friction torque of the wiper blade on the outer surface 11 of the window 10, and therefore of the coefficient of friction of the wiper blade. on the glass.

The method according to the invention consists in varying the scanning speed of the drive arm as a function of the degree of hydrophobicity of the exterior surface of the glass.

To this end, the method according to the invention implements the direct relationship which links the coefficient of friction between the wiper blade and the surface of the window and the quality of the hydrophobic treatment of the outer surface of the windshield. , ie the degree of hydrophobicity of this surface.

Thus, it is considered for example that the variations and changes in the evolution of the drive torque of the drive motor or motors are representative of the variations and changes in the evolution of the friction of the wiper blades on the outer surface of the visor. -broken.

Thus, an extremely high value of the coefficient of friction is characteristic of the presence of a new or almost new hydrophobic treatment.

In this case, the control method according to the invention aims to increase the wiping speed of the wiper.

For example, we cause an increase of at least 10% in the scanning speed compared to what the driver will have asked, or even compared to a nominal scanning speed determined according to what a rain sensor - such as sensor 50 - will have detected.

The decrease in the coefficient of friction over time is characteristic of a hydrophobic surface treatment which degrades, to return to conventional values of the coefficient of friction between a wiper blade and the hydrophobic untreated outer surface. a windshield.

In this case, the method according to the invention can make it possible to launch an operation of recharging the windshield with hydrophobic liquid, that is to say renewal of the hydrophobic treatment, for example under the control of the electronic unit 60 - by implementing means described above and integrated into the vehicle wiping system.

If the vehicle wiping system does not include such means, the method according to the invention and the wiping system makes it possible to warn the driver of the need to manually renew the hydrophobic treatment.

The diagram in FIG. 2 illustrates different characteristic values of the coefficient of friction between a wiper blade and the surface of a window to be wiped such as the windshield 10, with the time "t" on the abscissa and on the ordinate the coefficient of friction "C" expressed in relative value.

Typically, over time, the coefficient of friction is likely to change between three characteristic values of the coefficient of friction:

- a first value a which is characteristic of an untreated hydrophobic glass and with a new wiper blade;

- a value aa which is characteristic of an untreated hydrophobic glass and with a worn wiper blade;

- a value greater than or equal to b - often estimated as being equal to 2 - which is characteristic of a situation in which the windshield is hydrophobic and / or has just been the subject of hydrophobic treatment.

The diagram in FIG. 3 illustrates a first example of variation over time of the coefficient of friction between a wiper blade and the surface of a window to be wiped such as the windshield 10, with time and on the ordinate the coefficient of friction.

As can be seen in this diagram, from the instant t1 at which the value of the coefficient of friction becomes greater than or equal to the value b, the method according to the invention makes it possible to increase the scanning speed as indicated above.

The diagram in FIG. 3 illustrates a first example of variation over time of the coefficient of friction between a wiper blade and the surface of a window to be wiped such as the windshield 10, with time and on the ordinate the coefficient of friction.

As can be seen in this diagram, if we observe a gradual and slow decrease in the coefficient of friction from a value greater than the value b, we must consider that the hydrophobic coating of the windshield degrades - c '' is to say that its degree of hydrophobicity decreases - and, from a certain level of degradation (corresponding to time t2), and the method according to the invention makes it possible to trigger a renewal - automatic or manual - of the hydrophobic treatment.

In such a case, it is obviously not a question of taking into account such a reduction in the coefficient of friction between two successive uses of the wiping system, which would be characteristic of a change of a wiper blade. worn ice.

The implementation of the principles of the invention according to which the degree of hydrophobicity is estimated as a function of a parameter representative of the coefficient of friction between the wiper blade and the surface of the glass, makes it possible to propose a method for controlling or controlling the application of a hydrophobic treatment on the exterior surface of a window, characterized in that it consists in estimating the degree of hydrophobicity of the exterior surface of the window, and in initiating a step renewal of the hydrophobic treatment as a function of the estimated degree of hydrophobicity of the external surface of the glass.

Claims (21)

1. Method for controlling a system for wiping an external surface (11) of a window (10) of a motor vehicle having undergone at least one hydrophobic treatment, this system comprising at least one arm (31) of sweep drive of a wiper blade (30) which cooperates with the outer surface (11) of the window (10), characterized in that it consists in varying the sweep speed of the drive arm depending on the degree of hydrophobicity of the outer surface (11) of the window (10). 2. Method according to claim 1, characterized in that it consists in estimating the degree of hydrophobicity as a function of a parameter representative of the coefficient of friction between the wiper blade (30) and the surface of the window (10). 3. Control method according to claim 2, characterized in that it consists in modifying the scanning speed when said parameter reaches a determined threshold value representative of a determined threshold value of the degree of hydrophobicity of the external surface ( 11) of the window (10). 4. Control method according to claim 3, characterized in that it consists in increasing the scanning speed when said parameter becomes equal to or greater than a determined threshold value. 5. Control method according to claim 3, characterized in that it consists in reducing the scanning speed when said parameter becomes less than a determined threshold value. 6. Control method according to claim 2, characterized in that it comprises a step of renewing the hydrophobic treatment when said parameter becomes less than a determined threshold value. 7. Method according to claim 6, characterized in that said step of renewing the hydrophobic treatment comprises a step of alerting the user of the vehicle with a view to renewing the hydrophobic treatment. 8. Method according to claim 6 or 7, characterized in that said step of renewing the hydrophobic treatment consists in spraying hydrophobic liquid on the external surface (11) of the window (10) and in spreading hydrophobic liquid on the window ( 10) by means of a wiper blade (30). 9. Method according to any one of claims 2 to 8 for controlling a wiping system comprising an electric motor (40) for driving the drive arm (31), characterized in that said parameter is the temperature and / or the supply voltage of the electric motor (40), and / or the value of the mechanical torque produced by the drive motor during scanning. 10. Method according to any one of claims 2 to 8, characterized in that the threshold value of the coefficient of friction between the wiper blade (30) and the surface of the window (10) is greater than 0 , 5, preferably between 0.5 and 0.7, preferably equal to 0.6. 11. Method according to any one of the preceding claims of a wiping system in which the wiper blade (30) comprises a wiping blade (29), characterized in that said parameter is representative of the coefficient of friction between the wiping blade (29) and the surface of the glass (10). 12. System for wiping a surface of a window (10) of a motor vehicle, this system comprising at least one arm (31) for sweeping drive of a cooperating wiper blade (30) with an outer surface (11) of a window (10) of a motor vehicle having undergone at least one hydrophobic treatment, characterized in that it comprises: - a sensor for measuring a parameter making it possible to estimate the degree of hydrophobia of the external surface (11) of the window (10); - A circuit (60) for controlling the scanning speed of the drive arm (31) which modifies the scanning speed as a function of variations of said parameter. 13. System according to claim 12, characterized in that the degree of hydrophobicity of the external surface (11) of the window (10) is estimated by the control circuit as a function of a parameter representative of the coefficient of friction between the wiper blade (30) and the surface of the window (10). 14. System according to claim 13, characterized in that it comprises at least one reservoir (3) containing a hydrophobic liquid, a system of pipes (5) connecting this reservoir (3) to orifices (15) through which the liquid hydrophobic is projected in the direction of the exterior surface (11) of the window (10), a pump system (22) intended to circulate the liquid in the pipe system (5), and at least one brush (30) d wiping of the exterior surface (11) of the window (10) capable of spreading hydrophobic liquid on the exterior surface (11) of the window (10), and in that the hydrophobic liquid is sprayed in the direction of the exterior surface (11) of the window (10) when said parameter becomes less than a determined threshold value. 15. System according to claim 14, characterized in that it comprises means (60) capable of triggering an alert intended for a user of the vehicle with a view to renewing the hydrophobic treatment of the external surface (11) of the window (10), when said parameter becomes less than a determined threshold value. 16. System according to claim 15, characterized in that the scanning speed is modified by the control circuit (60) when said parameter reaches a determined threshold value representative of a determined threshold value of the degree of hydrophobicity of the outer surface (11) of the window (10). 17. System according to claim 16, characterized in that the control circuit increases the scanning speed when the friction coefficient becomes equal to or greater than a determined threshold value. 18. System according to claim 16, characterized in that the control circuit reduces the scanning speed when the friction coefficient becomes lower than a determined threshold value. 19. System according to any one of claims 13 to 18, characterized in that it comprises an electric motor (40) for driving the drive arm, and in that said parameter is the temperature and / or the voltage of the electric motor (40) and / or the value of the mechanical torque produced by the electric motor (40) of drive during sweeping. 20. System according to any one of claims 14 to 19, characterized in that the threshold value is greater than 0.5, preferably between 0.5 and 0.7, preferably equal to 0.6. 21. System according to any one of claims 13 to 20, characterized in that the wiper blade (30) comprises a wiper blade (29), and in that said coefficient of friction is the coefficient of friction between the wiping blade and the surface of the glass (10).