FR2845642A1 - Removal of pollutants in activated carbon filter, used in vehicle air conditioning system, heats activated carbon and flushes it with air which is discharged outside vehicle - Google Patents

Abstract

The activated carbon (45) is heated to the desorption temperature. Flushing air is passed through the filter unit (41). The air is discharged outside (26) the passenger compartment (16), thus preventing re-entry. Passage of air between filter and passenger compartment is blocked. The flushing air is drawn from the compartment and led to the exterior after flushing. An Independent claim is included for an equipment for use in the above method.

Description

The present invention relates to an air conditioning device

  passenger compartment of a motor vehicle comprising a conditioning group, a main air intake duct connecting the exterior of the passenger compartment to said conditioning group, a main air outlet duct connecting said conditioning group to the cabin, an activated carbon filter placed in one of said main ducts, a circulation unit adapted to circulate air in said ducts between the exterior and the cabin, through the filter and the

  conditioning group, following a variable path.

  Certain known air conditioning devices of this type comprise, downstream of a conventional combined filter, that is to say a filter composed of a layer of particulate filter and of a layer of carbon filter

  active, a block of activated carbon of significant thickness.

  Between the combined filter and the block of activated carbon, bypass means are arranged which make it possible to direct the air flow passing through the combined filter either directly to the conditioning group or to the second filtration stage consisting of the block of charcoal. The bypass means are controlled as a function of the pollution of the air surrounding the vehicle, this pollution

  being estimated by electronic detection means.

  Thus, the block of activated carbon, which is the source of significant pressure drops in the air conditioning circuit, is crossed only if external pollution is detected. The activated carbon block can be dimensioned so that it does not require any replacement throughout the life of the vehicle, only the combined filter in front

be periodically replaced.

  Such a device makes it possible to limit the pressure drops in current operation of the air conditioning system, as indicated above, but also to design combined filters for which the lifetime of the particle filtration layer and that of the activated carbon layer (or molecular filtration) are

substantially identical.

  Such a device is not entirely satisfactory

  due to the complexity, and therefore the cost of installation on a vehicle, of an electronic pollution detection system, and due to the pressure drops in the air conditioning circuit during the phases of operation in anti-pollution mode.

  The object of the invention is to resolve these drawbacks and to propose an air conditioning device as described above, the activated carbon filter of which does not introduce excessive pressure drops whatever the mode of air conditioning.

  (polluted environment or not), and not involving, under normal use, replacement of the filter throughout the life of the vehicle. Another object of the invention is to get rid of electronic pollution detection systems 20.

  To this end, an air conditioning device according to the invention comprises means for heating said filter, and means for controlling the heating means and the circulation unit, said control means being adapted to operate the means. heating and the circulation group selectively according to at least one normal operating mode, in which the heating means are inactive, and a pollutant removal mode contained in the filter, in which the heating means are active and l air passing through the filter is

  directed outwards without passing into the passenger compartment.

  Thanks to this arrangement, when heated and traversed by an air flow, the activated carbon filter releases the pollutants it has stored and regains an optimal filtration capacity, the pollutants then being discharged directly outside of the passenger compartment. In addition, the complexity of the air conditioning system is only slightly increased. According to an advantageous characteristic of the device according to the invention: - the conditioning group comprises an evaporator and a condensate evacuation pipe connecting said evaporator to the outside, in that the circulation group 10 comprises means for closing off the cabin air inlet and a fan placed upstream of said exhaust duct, and in that the control means are adapted to control, in order to pass from the normal operating mode to the exhaust mode, a on the one hand the closure of the sealing means, and on the other hand

  activation of the heating means from their inactive state, and vice versa to pass from the exhaust mode to the normal operating mode, so that the air passing through the filter during the exhaust mode is evacuated at 20 l outside by the condensate evacuation pipe.

  As a variant: - the device comprises a bypass duct connecting a downstream point relative to the filter to an upstream point of the main air duct, the circulation unit 25 comprises means for shutting off the air intake of passenger compartment, a fan placed in the main air duct between said downstream and upstream points, and means for closing off said bypass duct, and the control means are adapted to control, to switch from normal operating mode to mode evacuation, on the one hand the closure of the means for closing the passenger compartment air inlet and the opening of the means for closing the bypass air duct, and on the other hand the activation heating means from their inactive state, and vice versa to pass from the exhaust mode to the normal operating mode, so that the air passing through the filter during the exhaust mode is exhausted to the outside

through the bypass duct.

  In this latter configuration, the circulation unit can comprise a secondary fan placed in the bypass duct, and the control means can be adapted to switch said secondary fan from an inactive state to an active state, in which the air is circulated between downstream and upstream of the filter in the bypass duct, when changing from normal operating mode to exhaust mode, and vice versa when switching from exhaust mode to

normal running.

  Thanks to the arrangements which have just been described, the evacuation of pollutants outside the passenger compartment is carried out by existing channels in the air conditioners of

classic type.

  In another variant - the circulation unit comprises a reversible fan placed in the main air duct, and the control means are adapted to control, to go from normal operating mode to exhaust mode, the reversal of the direction of operation of the fan from its normal operating direction which sets the air in motion from the outside to the passenger compartment, and the activation of the heating means from their inactive state, and vice versa to switch from mode d exhaust in normal operating mode, so that air passing through the filter during exhaust mode is exhausted

  outside through the main air intake duct.

  Such a configuration requires minor fitting of the air ducts present in the air conditioners of

classic type.

  According to optional features of the invention: - the activated carbon filter is a combined filter comprising at least one layer of activated carbon and one layer of particulate filter material; and said layers are each integral with a

  support fixed relative to the main air duct, the support of the layer of particulate filter material being removable independently of the support of the layer of activated carbon.

  The invention also relates to a vehicle equipped with an air conditioning device as described above. The invention finally relates to a method for removing pollutants contained in an activated carbon filter of an air conditioning device for the passenger compartment of a motor vehicle, characterized in that the following operations are carried out: activated carbon at a desorption temperature; - a flow of air pollution control is passed through the activated carbon filter; and - the said air flow of pollution control is directed towards

  outside the passenger compartment, by prohibiting its passage through the passenger compartment.

  According to optional features of the process: - the air passage between the filter and the passenger compartment is closed; and - the air flow of pollution control is sucked into the passenger compartment and directed towards the outside after passage to the

through the activated carbon filter.

  The invention will now be described in more detail with reference to the accompanying drawings, in which: - Figure 1 is a schematic view of a device according to a first embodiment of the invention, in normal operating mode; - Figure 2 is a similar view in pollutant removal mode; - Figure 3 is a view similar to Figure 2 of a device according to a second embodiment of the invention; - Figure 4 is a view similar to Figure 1 10 of a device according to a third embodiment of the invention; - Figure 5 is a view of the device of Figure 4 in pollutant removal mode; Figure 6 is a view similar to Figure 1 of a device according to a fourth embodiment of the invention; and - Figure 7 is a view of the device of Figure

  6, in pollutant removal mode.

  FIG. 1 shows a device for conditioning the air in the passenger compartment of a motor vehicle,

  according to a first embodiment of the invention.

  This device includes, shown diagrammatically under the reference

  1, a conditioning group making it possible to treat the incoming air in order to supply, at the outlet, air at a modified temperature according to a user instruction.

  This conditioning group 1, which has an inlet 3 and an outlet 5, essentially comprises an evaporator 7 and,

downstream, an air heater 9.

  By convention, the terms "upstream" and "downstream", as well as the terms "inlet" and "outlet", will be understood according to the direction of air circulation under operating conditions of the device called "normal" , that is to say when the device operates in air conditioning mode, as opposed to the pollutant removal mode which is a marginal mode of operation. These

modes are explained below.

  The evaporator 7, which is a heat exchanger designed to cool an air flow passing through it and to dehumidify this air flow, is placed in an air duct

  in which is formed an orifice opening onto a conduit il for discharging the condensates from the evaporator 7, this orifice being formed at the level of the latter. The reference will designate either the orifice 10 and the condensate evacuation pipe.

  The conditioning group 1 comprises, downstream of the evaporator 7, a mixing chamber 13, fed by an air flow F having passed through the evaporator 7. Inside the mixing chamber 13, is arranged a movable shutter for mixing 14, the position of which is dependent on the temperature setpoint. This flap 14 distributes the air flow into a secondary flow F directly directed towards the outlet 15 of the chamber 13, and into a second secondary flow passing through an air heater 9 which defines a means of heating the air. At the outlet of the heater 9, this secondary flow, designated by F +, has a temperature, during the operation of the conditioning unit, higher than the air of the secondary flow F. The two secondary flows F. and F + are mixed at the outlet 15 of the chamber 13, to give a flow of conditioned air 25 F, substantially equal to the set temperature. We understand that for an overall air flow

  constant, the temperature of the conditioned air flow Fc is lower the more the position of the flap 15 directs a smaller quantity of air towards the air heater 9.

  From the outlet 5 of the conditioning group 1, the conditioned air F is delivered into the passenger compartment 16 via a distribution duct or main air outlet duct 17. This distribution duct can be opened, closed, or partially closed depending on the position of a distribution flap 19 placed in this conduit. Depending on the phases of use, this flap 19 can be operated automatically, as will be seen later, or manually by a user present in the passenger compartment. In practice, several distribution conduits 17, each equipped with a distribution flap 19, connect the outlet 5 of the conditioning group to the passenger compartment 16, so that several points in the passenger compartment are supplied with air conditioning. Only one of these conduits 17 has been shown and taken into consideration to explain the invention, for

reasons of clarity.

  The conditioning group 1 is supplied with air by a main air inlet duct 21 connecting the exterior 26 of the vehicle to the inlet 3 of the conditioning group 1. Generally, as shown in FIG. 1 , but also in the following Figures, the air conditioning device is provided with an air recycling duct 27 connected to the main duct 20 21 at a mixing section 29, in which a mixture is produced between air from outside and air from the passenger compartment to form a flow

of air to be conditioned.

  A mobile recycling flap 31 is provided in the recycling conduit 27 to be able to take several

  positions between a completely closed position of the recycling duct 27, and an at least partially open position. This component thus determines the proportion of recycled air coming from the passenger compartment into the air 30 which will be conditioned and then injected into the passenger compartment.

  The air conditioning device also comprises a fan 33 placed in the main duct 21 downstream of the mixing section 29, this fan 33 being controlled, during operation of the device, for

  put the moving air in the main duct 21.

  The air circulating in the main duct 21, in the form of the air flow Fo from the mixture between the recycled air and the air coming from the outside, passes through an active carbon filter 41 placed in the main duct 21, upstream of entry 3 of the packaging group. This filter 41 is composed of a first layer or first part of filter 43, forming a particle filter, and of a second layer or

  filter part 45, made of activated carbon.

  The filter 41 will also be called a "combined filter" insofar as it comprises at least two filtering layers of different natures, the first 43 being intended for filtering solid particles, and the second 45 having a molecular filter function. Preferably, the 15 layers 43, 45 are each secured to a rigid support fixed in the main conduit 21. At least the support of the first layer 43 is removably mounted in the conduit 21, independently from the support of the second layer 45, so that the particle filter part 43 can be disassembled and replaced

  independently of the active carbon filter part 45.

  It is known that an activated carbon filter can be regenerated and regain an optimal filtration capacity, provided that the active carbon filter is heated to a desorption temperature and the air filter passes through this filter, to rid the heated filter

pollutants it has stored.

  The desorption temperature to be reached in order to carry out the depollution of the activated carbon is generally between 80 and 100 ° C., this value depending on the

  material used and the type of pollutant to be released.

  The filter 41 is associated with heating means 51 designed and arranged in the air conditioning device so as to be able to heat, in the pollutant removal mode, the active carbon filter part 45. These heating means 51 essentially consist of resistive conductors 53 (hereinafter called "resistor"), and of an electrical supply 55 connected to the resistor 53. The resistor 53, symbolized in the Figures by a separate element from the filter material of the filter 45, actually consists, preferably, of the material

  filter itself which is electrically conductive.

  The heating means can then be defined essentially by means of electrical supply and

the filter material of the filter 45.

  The air conditioning device comprises by

  elsewhere means 57 for controlling the supply 55 and 15 of the circulation group defined below.

  The circulation unit means the organs described above which allow the movement of air in the air conditioning device, and mobile organs determining the direction of the air flows. In the example shown in FIG. 1, this circulation group comprises on the one hand the fan 33, and on the other hand the distribution flap 19 and the flap of

recycling 31.

  This is how the control means 57 are connected, to control their operation or their position respectively, on the one hand to the fan 33 and to the power supply 55, and on the other hand to the distribution flap

19 and recycling component 31.

  We will now describe the operation of the device with reference to Figures 1 and 2.

  In normal operating mode (Figure 1) The normal operating mode corresponds to blowing, in the passenger compartment 16, of air conditioning according to a user instruction. This normal operating mode is exclusive for cleaning the carbon filter part

active 45.

  In this operating mode, the control means 57 keep the heating means 5 51 inactive, that is to say that the resistor 53 is not supplied electrically by the supply 55. The filter part 45 is thus maintained at a temperature below the desorption temperature, so that it performs its filtering function without releasing pollutants. The distribution flap 19 and the recycling flap 31 are kept free to adjust their position by a user or possibly by automatic means. The fan 33 is active and circulates air from the mixing section 29 to the passenger compartment 16 through the conditioning group 1. Normally, condensates from the condensation of air from the flow Fo s' flow through

the orifice 11 towards the outside.

  In pollutant removal mode (Figure 2) This operating mode is dedicated to the regeneration of the activated carbon filter part 45,

  this regeneration aimed at restoring this part of the filter to its optimal filtration capacity, according to the process briefly described above. According to this method, the active carbon filter part 45 is heated to a desorption temperature and an air flow is passed through.

  depollution through this part of the filter.

  In order not to throw the

  pollutants released by the activated carbon, the air flow of depollution air is directed towards the outside 26, by preventing its passage through the passenger compartment 16.

  For this, the control means 57 activate the

  heating means 51, that is to say that the resistor 53 is supplied by the supply 55 so as to bring the activated carbon 45 to its desorption temperature.

  Simultaneously or beforehand, the distribution and recycling flaps 31 are brought, by the control means 57, into their closed position respectively of the distribution conduit 17 and of the recycling conduit 27, 5 so as to prevent any penetration of the air pollution in the passenger compartment 16. As for the fan 33, it is kept active by the control means 57, according to an operation in the same direction as during the normal operating mode, but according to a rotation speed 10 which can be different depending on the air flow desired for

  decontaminate the activated carbon properly 45.

  It is understood, in view of FIG. 2, that the pollution control air is blown outwards 26 through the condensate evacuation pipe 11, so that any penetration of the pollution control air into the passenger compartment is avoid. The construction and the method which have just been described make it possible to carry out the regeneration of the activated carbon 45 of the filter 41 by means of minor adjustments to the 20 air conditioning devices known and currently mounted on certain vehicles. In particular, pollutants are evacuated outside the passenger compartment by conduits

  existing in conventional packaging systems.

  In Figure 3, there is shown an air conditioning device according to a second embodiment of the invention, in the pollutant removal mode, the normal operating mode being identical to that of the previous embodiment , and can be

  also shown in Figure 1.

  Referring to this Figure 3, we understand that to switch from one mode to another, we reverse the direction of rotation of the fan 33 by a corresponding setpoint from the control means 57, and closes the recycling conduit 27 through recycling component 31. Unlike

  first embodiment of the invention, the distribution flap 19 is forced into the open position, so that the air for pollution control comes from the passenger compartment 16 via the distribution duct 17, passes through the conditioning group 1, l evaporator 7, then the filter 41, before being evacuated to the outside 26 by the main duct 21.

  As in the previous case, the control means 57 activate the heating means 51 simultaneously with the closure of the recycling conduit 27 and the opening of the distribution conduit 17, or following the closure of the recycling conduit. recycling and opening of the distribution duct. Preferably, in the latter case, the distribution flaps 19 and the recycling flaps 31 are respectively open and closed, while the direction of rotation of the fan 33 is reversed, before the activation of the means of

heating 51.

  Again, this solution does not generate

  additional space requirement of the air conditioning system.

  On the other hand, it may be necessary to provide a fan which can operate with a high level of performance regardless of its direction of rotation. Such

fan will be called "reversible".

  In Figures 4 and 5, there is shown an air conditioning device according to a third embodiment of the invention, these Figures respectively illustrating its normal operating mode and its pollutant removal mode. This embodiment differs from that of FIG. 3 only in that the fan 33 is replaced by a set of two fans 133, 134. The main fan 133 is arranged downstream of the mixing section 29, as it was the case in the previous embodiments, while the secondary fan 134 is arranged upstream of the mixing section 29, in the main duct 21 connecting the exterior 26 to the conditioning group 1. These fans 133, 134 operate from as follows - in normal operating mode (FIG. 4), the motor of the secondary fan 134 is not supplied, so that the latter is kept completely passive by the control means 57, while the motor of the main fan 133 is supplied so as to circulate the air in the main duct 21 from upstream to downstream of the device. As in the previous case, the heating means 51 are then inactive and the flaps 19 and 31 are free; in pollutant removal mode (FIG. 5), the control means 57 cut off the supply of the motor to the main fan 133, so that the latter is purely passive, while they supply the motor to the secondary fan 134 so as to circulate the air in the main duct 21 in the opposite direction. As in the previous embodiment, the heating means 51 are then activated, while the distribution flaps 19 and recycling 31 are controlled, by the control means 57, respectively at the opening of the duct.

  distribution 17 and closing of the recycling conduit 27.

  It will be understood that each of the two fans 133, 134 only operates actively in a respective direction of rotation different from that of the other fan. Each of the two fans 133, 134 can therefore be designed to provide optimum performance for a given direction of rotation. This solution, compared to that set out with reference to FIG. 3, even if it supposes the installation of two motor-driven fan groups, makes it possible to use simpler fans and associated motors.

and lower cost.

  With reference to Figures 6 and 7, we will now

  describe a fourth embodiment of the invention.

  In this example, a secondary bypass conduit 201 is provided connecting a point of the main conduit 21 upstream of the mixing section 29, to a point of the same main conduit 21 located downstream of the filter 41 and upstream of the entry 3 of the conditioning group. These points respectively define an outlet 203 and an inlet 205 of the bypass duct 201. The outlet 203 and the inlet 205 are each provided with shutter means 207, 209, in the form of movable flaps connected to the control means 57. These shutters 207, 209 can selectively assume a closed or open position as a function of a

setpoint of the control means 57.

  The main fan 133 is placed in the main duct 21 between the mixing section 29 and the filter 41, as in the previous embodiment, and a secondary fan 134 is arranged in the bypass duct 201. These two fans 133, 134 are

  controlled by the control means 57.

  In normal operating mode (Figure 6), the 20 flaps 207 and 209 are kept in the closed position by the control means 57, the main fan 133 is activated so as to direct the air in the main duct 21 from upstream to downstream of the device, while the fan 134 is kept inactive. As in the previous embodiments, the distribution 19 and recycling components 31

are then free.

  In pollutant removal mode (Figure 7), the flaps 207, 209 of the bypass duct 201 are open, while the distribution flap 19 is forced into the closed position and the recycling flap 31 is forced into the closing of the main duct 21 upstream of the recycling duct 27. The control means 57 keep the fan 133 active in the same direction of rotation, if necessary with a different operating speed, and control the activation of the secondary fan 134 in a direction capable of circulating the air in the bypass duct 201 from the inlet 205 to the outlet 203. It is understood that the air contained in the passenger compartment 16 is sucked in through the filter 41 via the recycling duct 27 and the

  main duct 21, towards the bypass duct 201 then directed towards the outside 26 by the inlet of the main duct 21. This intake of air from the passenger compartment is carried out by the combined action of the main fans 133 and secondary 10 fans 134 .

  Simultaneously, the residual air contained in the conditioning unit 1 is sucked into the bypass duct 201 and directed towards the outside 26 via the inlet of the

main duct 21.

  According to this embodiment, it is not necessary to use fans of the reversible type, that is to say that can operate with good performance.

  in the two opposite directions of rotation.

  Whatever the embodiment of the invention described above, the method of removing the pollutants contained in the activated carbon from the filter 41 can be executed at any time during the life of the vehicle, with the sole restriction of one execution outside the passenger compartment air conditioning phases. In other words, the regeneration of activated carbon requires the interruption of the air conditioning of the passenger compartment, so that the pollutants can be discharged directly outside without passing

through the passenger compartment.

  The pollutant removal mode can for example be carried out automatically depending on the conditions.

  use of the vehicle or predetermined cycles.

  In particular, the control means can be programmed to carry out the depollution of the activated carbon only

  when stopping the vehicle and / or after a certain number of kilometers traveled since the previous depollution.

Claims (11)

  1. Method for discharging pollutants contained in an activated carbon filter of a motor vehicle cabin air conditioning device, characterized in that the following operations are carried out: - the activated carbon is heated (45 ) at a desorption temperature; - A flow of depollution air is passed through the activated carbon filter (41); and - directing said air pollution control air towards the outside (26) of the passenger compartment, preventing its passage in the passenger compartment (16).   2. Method according to claim 1, characterized   in that the air passage between the filter (41) and the passenger compartment (16) is closed.   3. Method according to claim 1, characterized in that the air flow of pollution control is sucked into the passenger compartment (16) and directed towards the outside (26) after   passage through the activated carbon filter (41).   4. Motor vehicle cabin air conditioning device comprising a conditioning group (1), a main air inlet duct (21) connecting the exterior (26) of the passenger compartment to said conditioning group (1), a main air outlet duct 25 (17) connecting said conditioning group (1) to the passenger compartment (16), an activated carbon filter (41) placed in one (21) of said ducts main, a circulation group (19, 31, 33; 133, 134; 207, 209) adapted to circulate air in said conduits between the exterior (26) and the passenger compartment (16), through of the filter (41) and of the conditioning unit (1), along a variable path, characterized in that it comprises means (53, 55) for heating said filter, and means (57) for controlling the heating means (53, 55) and   circulation group (19, 31, 33; 133, 134; 207, 209), said control means (57) being adapted to operate the heating means and the circulation group selectively according to at least one normal operating mode , in which the heating means (53, 55) are inactive, and a mode for discharging pollutants contained in the filter (41), in which the heating means (53, 55) are active and the air passing through it filter (41) is directed towards the outside (26) without passing into the passenger compartment (16).   5. Device according to claim 4, characterized in that the conditioning group (1) comprises an evaporator (7) and a condensate evacuation pipe (11) connecting said evaporator (7) to the outside (26) , in that the circulation unit (19, 31, 33; 133, 134) comprises means (19) for closing the passenger compartment air inlet and a fan (33; 133, 134) placed in upstream of said evacuation duct (11), and in that the control means (57) are adapted to control, to pass from the normal operating mode to the evacuation mode, on the one hand the closing of the shutter (19), and secondly the activation of the heating means (53, 55) from their inactive state, and vice versa to pass from the evacuation mode to the normal operating mode, so that 25 l air passing through the filter (41) during the exhaust mode is exhausted to the outside (26) through the duct (11) condensate drain.   6. Device according to claim 4, characterized in that it comprises a bypass duct 30 (201) connecting a downstream point relative to the filter (41) to an upstream point of the main air duct (21), in that that the circulation unit (19, 31, 133, 134, 207) comprises means (19) for closing off the cabin air intake, a fan (133) placed in the main air duct ( 21) between said downstream and upstream points, and means (207, 209) for closing said bypass duct (201), and in that the control means (57) are adapted to control, to switch from the operating mode normal to exhaust mode 5, on the one hand, the closing of the means (19) for closing the passenger compartment air inlet and the opening of the means (207, 209) for closing the air duct bypass air (201), and on the other hand the activation of the heating means (53, 55) from their inactive state, and conversely to pass from the evacuation mode to the operating mode normal, so that air passing through the filter (41) during the exhaust mode is exhausted at   outside (26) by the bypass duct (201).   7. Device according to claim 6, 15 characterized in that the circulation unit comprises a secondary fan (134) placed in the bypass duct (201), and in that the control means (57) are adapted to pass said secondary fan (134) from an inactive state to an active state, in which the air 20 is circulated between the downstream and the upstream of the filter (41) in the bypass duct (201), during the change from normal operating mode to evacuation mode, and vice versa when changing from evacuation mode to evacuation mode normal running.   8. Device according to claim 4, characterized in that the circulation group (19, 31, 33) comprises a reversible fan (33) placed in the main air duct (21), and the control means (57) are adapted to control, to pass from the normal operating mode to the exhausting mode, the reversal of the operating direction of the fan (33) from its normal operating direction which sets the air in motion from the outside (26) to the passenger compartment (16), and the activation of the heating means (53, 55) from their inactive state, and vice versa to pass from the evacuation mode to the normal operating mode, so that the air passing through the filter (41) during the exhaust mode is exhausted to the outside (26) by the main air inlet duct (21). 9. Device according to any one of   Claims 4 to 8, characterized in that the activated carbon filter (41) is a combined filter comprising at least one layer of activated carbon (45) and a layer of particulate filter material (43).   10. Device according to claim 9, characterized in that said layers (43, 45) are each secured to a support fixed relative to the main air duct (21), the support of the layer of particulate filter material. (43) being independently removable   of the support for the layer of activated carbon (45).   11. Vehicle equipped with an air conditioning device according to any one of Claims 4 to 10.