FIELD OF THE INVENTION

The invention relates to an ultraviolet air filter for a vehicle cabin.

An air cabin filter is an important component in any vehicle's ventilation system, to the extent that such a filter protects the passengers from contaminants in the air they breathe.

More specifically, the cabin air filter helps remove pollutants, including pollen and dust, from the air entering within the vehicle cabin. This filter is usually located behind the glovebox and cleans the air as it moves through the vehicle's Heat-Ventilation-Air Conditioning system (HVAC system).

The filter is generally a small pleated unit which can be made of an engineered material or paper-based, or multifiber cotton. Before air can move into the interior of the cabin of the vehicle, it goes through this filter, trapping any contaminants within the air in order to prevent them from infiltrating the vehicle.

However, such filters are passive filters that do not permit to destroy viruses that may be contained in the air penetrating inside the vehicle cabin or limit the presence of ozone which is harmful for the driver and the passengers of the vehicle.

The invention aims to remedy these drawbacks.

SUMMARY OF THE INVENTION

The terms "invention", "the invention", "this invention" and "the present invention" used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the detailed description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings and each claim.

More specifically, the invention is directed to an air cabin filter for a vehicle comprising:

- a housing having an air inlet and an air outlet, and

- a fan able to generate an air flow between the air inlet and the air outlet,

- a decontamination module positioned between the air inlet and the air outlet, said decontamination module comprising:

- a particle filter, and

- a plurality of ultraviolet light emitting diodes consisting of:

- ultraviolet light emitting diodes of type-C having a wavelength between 260nm and 280nm, and/or

- ultraviolet light emitting diodes of type-A having a wavelength between 315nm and 400nm, and

- a controller configured to operate the ultraviolet light emitting diodes.

The invention allows to provide an air cabin filter not only able to remove particle from an air flow entering the cabin of the vehicle, but also to destroy viruses and to dissociate ozone molecules in order to avoid ozone pollution within the vehicle.

According to a particular embodiment of the invention, the air cabin filter further comprises:

- at least one sensor selected among a temperature sensor or a hygrometric sensor, or preferably both sensors, for detecting seasons, - the controller being configured to operate the ultraviolet light emitting diodes as a function of the seasons.

According to a particular embodiment of the invention, the air cabin filter further comprises:

- an ozone sensor for detecting ozone pollution period during which an ozone concentration is superior to a predetermined threshold,

- the controller being configured to activate the ultraviolet light emitting diodes during the pollution period in order to reduce ozone concentration.

According to a particular embodiment of the invention, the air cabin filter further comprises:

- an air flow sensor for measuring a flow rate of air circulating through the air cabin filter,

- the controller being configured to adapt a power supplied to the ultraviolet light emitting diodes as a function of the flow rate measured by the air flow sensor.

According to a particular embodiment of the invention, the decontamination module further comprises an ozone generator intended to be activated when the vehicle is stopped and the vehicle cabin is empty in order to disinfect the vehicle cabin.

According to a particular embodiment of the invention, the ozone generator consists in a plurality of discharge tubes and/or ultraviolet light emitting diodes having a wavelength between 160 nm and 190 nm, and preferably at 185nm.

According to a particular embodiment of the invention, the ultraviolet light emitting diodes are mounted on at least one printed circuit board extending perpendicular to the particle filter. According to a particular embodiment of the invention, the decontamination module comprises a plurality of printed circuit board mounted on a plurality of PCB holders extending parallel to each other.

According to a particular embodiment of the invention, the decontamination module comprises a case, the PCB holders being removably coupled to said case so that the number of PCB holders holding the printed circuit board can be adjusted.

According to a particular embodiment of the invention, the case comprises means for adapting a distance between adjacent PCB holders.

According to a particular embodiment of the invention, a bottom side of at least one PCB holder is polished to create mirror effect for the light emitting diodes mounted on a PCB holder facing the polished bottom side.

According to a particular embodiment of the invention, the decontamination module comprises at least one obstacle for creating air flow turbulence in order to increase the exposition period of the airflow to the ultraviolet light emitting diodes.

According to a particular embodiment of the invention, the air cabin filter further comprises a piece of magnesite in order to remove carbon dioxide.

According to a particular embodiment, the air cabin filter further comprises a carbon dioxide sensor for determining an air quality within a vehicle cabin, the controller being configured to increase a power of the fan if a carbon dioxide concentration value returned by the sensor exceeds a predetermined threshold

The invention is also directed to a vehicle comprising an air cabin filter as previously defined. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood on reading the following description and examining the Figures that accompany it. These Figures are provided by way of illustration only and are in no way limiting on the invention.

Figure 1 a shows a perspective view of an air filter according to the present invention;

Figure 1 b shows an exploded view of an air filter according to the present invention;

Figure 2a shows a perspective view of a decontamination module integrated in an air filter according to the invention;

Figure 2b shows an exploded view of a decontamination module integrated in an air filter according to the invention;

Figure 3 shows a top view of a printed circuit board supporting light emitting diodes of the decontamination module according to the present invention;

Figure 4a shows a typical spectrum and radiation pattern of an ultraviolet light emitting diode of the C type used in the air filter according to the invention;

Figure 4b shows a typical spectrum and radiation pattern of an ultraviolet light emitting diode of the A type used in the air filter according to the invention;

Figure 5a shows a first operating mode of an air filter according to the present invention;

Figure 5b shows a second operating mode of an air filter according to the present invention;

Figure 5c shows a third operating mode of an air filter according to the present invention; Figure 5d shows a fourth operating mode of an air filter according to the present invention.

Similar elements shown on the drawings keep the same reference number.

DETAILED DESCRIPTION

The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.

Figures 1 a and 1 b show an air filter 10 for a vehicle comprising a housing 1 1 having an air inlet 12 intended to be in communication with external air surrounding the vehicle and an air outlet 13 intended to be in communication with a cabin of the vehicle. A fan 15 is able to generate an air flow between the air inlet 12 and the air outlet 13. The housing 1 1 can be formed by walls 16 of various shapes defining guiding channels for the air flow between the air inlet 12 and the air outlet 13.

The air filter 10 further comprises a decontamination module 17 positioned between the air inlet 12 and the air outlet 13. The decontamination module 17 comprises a particle filter 18 and a plurality of ultraviolet light emitting diodes 20, as it can be seen on figures 2a and 2b.

The particle filter 18 is a classic particle filter which can be made of an engineered material or paper-based, or multifiber cotton, or any other material adapted to the application. The ultraviolet light emitting diodes 20 consist of ultraviolet light emitting diodes 20 of type-C having a wavelength between 260nm and 280nm, and/or ultraviolet light emitting diodes 20 of type-A having a wavelength between 315nm and 400nm. As matter of fact, it is possible to use only one type of ultraviolet light emitting diodes 20 (type A or type C) and both types of ultraviolet light emitting diodes 20 (type A and type C). The wavelength range between 260nm and 280nm is however more efficient in order to destroy viruses and transform ozone. Figure 4a shows a typical spectrum and radiation pattern for an ultraviolet light emitting diode of the C type used in the air filter 10 according to the invention and Figure 4b shows a typical spectrum and radiation pattern for an ultraviolet light emitting diode of the A type used in the air filter 10 according to the invention.

A controller 21 is configured to operate, i.e activate or deactivate, the ultraviolet light emitting diodes 20. Preferably, at least one sensor selected among a temperature sensor 22 or a hygrometric sensor 23, or preferably both sensors 22, 23 are used to detect the seasons. The controller 21 is configured to operate the light emitting diodes 20 as a function of the seasons. In particular, the controller 21 is configured to activate the light emitting diodes 20 during winter in order to eradicate viruses contained in the air. During summer where the quantity of viruses contained in the air decreases, the controller 21 is configured to deactivate the light emitting diodes 20. During spring or autumn, the activation or deactivation of the light emitting diodes 20 depends on the value returned by the sensors 22, 23.

The air filter 10 also comprises an ozone sensor 24 used for detecting ozone pollution period during which an ozone concentration is superior to a predetermined threshold. The ozone sensor 24 is positioned upstream the light emitting diodes 20. The controller 21 is configured to activate the light emitting diodes 20 during the pollution period in order to reduce ozone concentration. The decontamination module 17 may further comprise an ozone generator 25 for disinfecting the cabin. The ozone generator is intended to be activated when the vehicle is stopped and the vehicle is empty. The ozone generator 25 generates a gas containing a high concentration of ozone for depolluting the surfaces of the different components installed within the cabin (wheel, seats, dashboard, and others). The production of ozone is limited in time for security reason. The ozone generator 25 can consist in a plurality of discharge tubes and/or ultraviolet light emitting diodes 20 having a wavelength between 160nm and 190nm, and preferably at 185nm. This wavelength range allows the diodes 20 to transform some air molecules into ozone. Alternatively, the ozone generator 25 is an independent gas source containing ozone and embedded in the air filter 10.

As it can be seen on figures 2a and 2b, the ultraviolet light emitting diodes 20 are mounted on at least one printed circuit board 28 extending perpendicular to the particle filter 18. In particular, the printed circuit board 28 extends perpendicular to the face of the particle filter 18 through which passes the air. The printed circuit board 28 extends parallel to the air flow.

In the example of figure 3, the printed circuit board 28 comprises 3 rows of 10 diodes so 30 diodes in total. However, it is clear that the printed circuit board 28 could comprise more or less than 30 diodes, more or less than 3 rows of diodes, and more or less than 10 diodes per row. The printed circuit board 28 comprises also at least one driver 29 able to control the current powering the light emitting diodes 20. In this particular example, the printed circuit board 28 comprises 3 drivers (1 driver per row of diodes). However, the number of drivers can vary depending of the application.

A control unit 30 commands the drivers 29 in a pulsed mode, for example a PWM (Pulse Width Modulation mode) or alternatively in a continuous mode. The printed circuit board 28 (or "PCB") is mounted on a corresponding PCB holder 32. Insulation means can be placed between the printed circuit board 28 and a corresponding PCB holder 32.

The design of the decontamination module 17 is flexible so that the number of PCB holders 32 supporting the printed circuit boards 28 and the distance between PCB holder 32 can be adjusted as desired in accordance with the application. Such a configuration allows to increase or decrease the level of UV light irradiation inside the decontamination module 17. For example, il will be possible to include more PCB holders 32 and corresponding printed circuit board 28 in the air filter 10 of a vehicle having a large cabin than in an air filter 10 designed for a vehicle having a small cabin.

More specifically, the decontamination module 17 comprises a case 33 and a plurality of PCB holders 32 extending parallel to each other. The PCB holders 32 are removably coupled to said case 33. In the present embodiment, the case 33 comprises two lateral walls 34 to which are coupled the PCB holders 32. To this end, the PCB holder 32 can be mounted on the lateral walls 34 by means of removable fasteners 35, or by mean of guiding rails such the guiding rails used classically in computer devices for mounting circuit board. This allows to replace easily a dysfunctional device or to adapt the number of printed circuit boards 28 required for the application.

The case 33 may also comprise means 36 for adapting a distance between adjacent PCB holders 32. These means 36 can be fasteners mounted at different positions on the lateral walls 34 of the case 33 so that the distance between the PCB holders 32 can be modified by selecting fasteners relatively close or far from each other, or a sliding link comprising a rail extending perpendicular to the PCB holders 32, or any other mechanical link adapted to the application.

Advantageously, the case 33 defines a cavity 37 at one of its extremity configured to receive the particle filter 18. So one portion of the case 33 of the decontamination module 17 is configured to receive the PCB holders 32 and another portion of the case 33 is configured to receive the particle filter 18. This allows to obtain a very compact decontamination module 17 that can be easily integrated within the air filter 10 according to the invention.

A bottom side 39 of at least one PCB holder 32 may be polished to create mirror effect for the light emitting diodes 20 mounted on a lower PCB holder 32 facing the polished bottom side 39. The radiation of the UV diodes 20 is therefore reflected by the bottom side 39 of the PCB holder. This feature allows to create uniform irradiation in the whole volume extending between two adjacent PCB holders 32.

The decontamination module 17 may comprise obstacles 40 such as columns, or protrusions or blades, for creating air flow turbulence in order to increase the exposition period of the air flow to the ultraviolet light emitting diodes 20. The obstacles 40 may be positioned at the entry of the air filter 10.

The case 33 of the decontamination module 17 and/or the PCB holder 32 are made of a metallic material such as aluminum, magnesium, or steel. Alternatively, the case 33 can be made of a plastic or a composite material or any other material adapted to the application.

The table below shows the ultraviolet dose received by the air treated by a filter according to the invention as a function of a varying air flow rate:

The table has been obtained for an air filter 10 comprising 3 PCB holders and corresponding printed circuit boards 28 generating an energy of 1.8 Joules.

The distance between two adjacent PCB holders 32 is of 3 centimeters. Each printed circuit boards 28 comprises 30 diodes of the UV-C type. The first column corresponds to the fixed volume of the air filter 10 of 4856 cm ³ .

The second column corresponds to the flow rate of air passing through the filter expressed in cm ³ /s.

The third column corresponds to the radiation time t of the air passing in front of the light emitting diodes 20, i.e exposure duration of air to UV.

The fourth column corresponds to energy per surface expressed in Joule/cm ² .

The fifth column corresponds to the UV dose expressed in mJ/s.

The sixth column corresponds to the flow rate of air passing through the filter expressed in m ³ /s.

The seventh column corresponds to the fan speed.

Virus being destroyed for a dose of at least 5mJ/s, such a configuration allows to treat efficiently an air flow up to 170m ³ /h.

In this example, the power of the light emitting diodes 20 is fixed and do not vary as a function of the air flow rate. Alternatively, the air filter 10 may comprise an air flow sensor 42 for measuring a flow rate of air circulating through the air cabin filter. The controller 21 is configured to adapt the power supplied to the light emitting diodes 20, as a function of the flow rate measured by the air flow sensor 42.

Figures 5a-5d show different operating modes of the air filter 10. Figure 5a illustrates a first operating mode wherein the UV-A and/or UVC-C light emitting diodes 20 are activated to treat external air 43 coming from outside the vehicle cabin while the ozone generator 25 functioning at 185nm are deactivated. This first operating mode is carried out for example during summer season or during an ozone pollution period. The air recycling system is deactivated. Figure 5b illustrates a second operating mode of the air filter 10. This operating mode is similar to the first operating mode except that air recycling system is activated. In this operating mode, air coming from outside the vehicle is blocked.

Figure 5c illustrates a third operating mode wherein the UV-A and/or UVC-C light emitting diodes 20 are deactivated while the ozone generator 25 is activated. This third operating mode is carried out for sanitizing the vehicle cabin when the car is stopped and the vehicle is empty from the passengers and the driver.

Figure 5d illustrates a fourth operating mode wherein the air filter 10 is position upstream an air conditioning evaporation device 45 and a heater 46.

It has to be noted that the air recycling function cannot operate continuously because it is necessary to remove the carbon dioxide (CO2) rejected by the passengers and the driver. The removal can be achieved by a piece of magnesite 47 integrated within the air filter 10 (cf. figure 1 a).

In a variant, the sensors 22, 23 for detecting the season and/or the ozone sensor 24 may be removed. So the cabin air filter 10 may be operated only as a function of the seasons or only as a function of the ozone pollution period detected.

The air filter 10 may also comprise a carbon dioxide sensor 48 for determining an air quality within the vehicle cabin (cf. figure 1 b). The controller 21 is configured to increase a power of the fan 15 if a carbon dioxide concentration value returned by the sensor 48 exceeds a predetermined threshold. The predetermined threshold is for example set at 800ppm or any other value adapted to the application.

The invention is also directed to a vehicle comprising an air filter 10 as described above. Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and sub-combinations are useful and may be employed without reference to other features and sub-combinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications may be made without departing from the scope of the claims below.