Abstract:
The invention concerns a heating, ventilating and/or air conditioning device comprising at least an air distribution channel having a downstream end, and at least an air diffusing element arranged at said one downstream end. The invention is characterized in that the air diffusing element ( 1 ) comprises a support ( 11 ) provided with through orifices ( 17 ) and covered over at least one of its faces with a material ( 12, 16 ), having air resistance ranged between 10 N.s.m −3  and 180 N.s.m −3 .

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The subject of the present invention is a heating, ventilating and/or air conditioning device comprising at least one air distribution channel having one downstream end, and at least one air diffusion element placed at one said downstream end, in order to diffuse the air in the vehicle passenger compartment. 
     (2) Description of Related Art 
     Usually, air is diffused in the vehicle passenger compartment via a plurality of nozzles. These systems have drawbacks: they cause currents of air and poor distribution of temperature in the passenger compartment, which adversely affects the comfort of the passengers. 
     To overcome this problem, a known solution consists in diffusing the air through a porous surface, which extends over the dashboard. These porous surfaces are generally obtained by providing a large number of small holes perforated through a surface impermeable to air, as mentioned in French Patent Application FR 2 074 471 and in British Patent GB 1 040 469. 
     In the known devices, the porous surfaces are either too porous, in which case the flow of air in the air diffusion nozzles associated with the diffusion is too great, or insufficiently porous, in which case the pressure drop is too high and the dynamic for controlling the temperature of the passenger compartment is too weak and its effect is not felt in a satisfactory manner by the passengers. 
     BRIEF SUMMARY OF THE INVENTION 
     The subject of the present invention is a heating, ventilating and/or air conditioning device which makes it possible to overcome this problem and to obtain regular diffusion of air which provides sufficient temperature control in the passenger compartment while preventing the aforementioned air current phenomena from being caused. 
     Within this aim, the invention relates to a heating, ventilating and/or air conditioning device comprising at least one air distribution channel having one downstream end, and at least one air diffusion element placed at one said downstream end, characterized in that at least one said air diffusion element, having, for example an area of between 0.02 m 2  and 0.5 m 2  and preferably between 0.04 m 2  and 0.2 m 2 , comprises a support provided with through-orifices and covered over at least one of its faces with a material having an air resistance of between 10 N.s.m −3  and 180 N.s.m  −3 . 
     Advantageously, said air resistance is less than 80 N.s.m −3 . 
     The material may be a textile, especially a multilayered textile. 
     The textile and the support may advantageously be secured by thermal adhesion. 
     It is advantageous for the support to be rigid or semirigid. 
     According to a preferred embodiment, the support is thermoformed. 
     The support may, for example, be a honeycomb. 
     The invention also relates to a heating, ventilating and/or air conditioning device comprising at least one air distribution channel having one downstream end, and at least one air diffusion element placed at one said downstream end, characterized in that at least one said air diffusion element, having, for example, an area of between 0.02 m 2  and 0.5 m 2  and preferably between 0.04 m 2  and 0.2 m 2 , has an air resistance of between 10 N.s.m −3  and 180 N.s.m −3 . 
     Said air assistance is advantageously less than 80 N.s.m −3 . 
     The air diffusion element may in particular comprise a perforated plate, a grid, a cellular open-pore plastic or an alveolar material. 
     It is advantageous that the air diffusion element comprises at least one textile. 
     The air diffusion element may comprise a rigid or semirigid support for said textile. 
     The support may, for example, be a perforated plate. 
     It is advantageous that the support has an air resistance at least half and preferably at least one 10 th  that of said textile. 
     According to a preferred embodiment, the support has through-orifices. 
     The textile may be woven or non-woven, for example, a velvet. 
     The textile may be multilayered. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     Other advantages and characteristics of the invention will become better apparent on reading the following description, given by way of nonlimiting example, in relation to the appended drawings, in which: 
     FIG. 1 shows a view of the dashboard of a vehicle equipped with a device according to the present invention; 
     FIG. 2 shows a sectional view of an exemplary embodiment of a composite panel according to the invention; 
     FIG. 3 shows a view in section and in perspective of an embodiment of a composite panel according to the invention; 
     FIGS. 4 a  to  4   d  show embodiments of supports with through-cells according to some embodiments of the invention; 
     FIG. 5 shows a graph of pressure drop as a function of the flow rate of a device according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The dashboard  3  shown in FIG. 1 comprises a fascia  3 , an instrument panel  4 , a steering wheel  5 , a console  6  and, at the upper part of the dashboard  3 , and adjoining the windshield  2 , a surface air-diffusion element  1  which extends, for example, over the entire width of the vehicle, and which makes it possible to provide a distributed air diffusion, with a low surface flow rate, in order to provide diffusion of air without the air current being perceptible to the passengers and with a uniform distribution of the temperature in the vehicle passenger compartment. 
     The air diffusion is provided by a material, especially a textile, having an air resistance of between 10 N.s.m −3  and 180 N.s.m −3 . In particular, the use of a woven or nonwoven textile is particularly advantageous in this sense since it provides a uniform and truly surface diffusion while providing a covering for the dashboard which is compatible with the aesthetic requirement of designers. 
     For small vehicles, whose passenger compartment is not spacious (for example, two-seater vehicles, urban vehicles), a higher pressure drop is permissible through the textile  12 . The latter may have an air resistance which is high, but less than 180 N.s.m −3 , which provides a dynamic for controlling the temperature of the passenger compartment which satisfies passenger comfort. 
     For vehicles whose passenger compartment is larger, the dynamic for controlling the temperature of the passenger compartment must also enable the temperature of the rear space of the vehicle to be controlled within a satisfactory time period. In this case, an air resistance of less than 80 N.s.m −3  will be chosen. 
     As shown in FIG. 2, the air diffusion element  1  may be a composite panel comprising at least one said material, especially a textile  12  and a support  11 , for example a rigid or semirigid support  11 . The support  11  may be a frame to which the permeable layer  12  is fastened. Alternatively, the support has two through-holes  14  comprising walls  15  which provide the mechanical properties of the assembly. This support  11  provides the rigidity and the shaping of the panel thus constructed. The support  11  may be a grid, a perforated plate, or an alveolar material, for example honeycombed, having through-cells. In this way, the air diffusion element  1  is integrated with the dashboard  3  both visually and mechanically. The cross section of the end of the pipe  16  has an area, for example, of between 0.02 m 2  and 0.5 m 2  and preferably between 0.04 m 2  and 0.2 m 2 . 
     A main air flow F is diffused by a divergent air intake  16  and the through-cells  14  produce a first subdivision of this flow parallel to their axis and these subdivided flows F′ then pass through the material  12 , for example a textile, in order to produce the function sought. 
     The through-cell structure thus forms small channels improving the homogenization of the flow, and the pressure drop is mainly due to the material  12  (and/or  16 ). 
     As shown in FIG. 3, the composite panel  1  may comprise two textile layers  12  and  16  on either side of the through-cell structure  11  which has through-orifices or cells  17 . The air resistance accumulated at these two layers  12  and  16  is between 10 N.s.m −3  and 180 N.s.m −3 , and more particularly, less than 80 N.s.m −3 . This structure is advantageous, since it provides better rigidity of the assembly because of the fact that films or textiles  12  and  16  are present on either side of the structure  11 . This composite also has good acoustic absorption characteristics, which means that the passengers perceive the noise of the heating, ventilating and/or air conditioning device less. 
     FIGS. 4 a  to  4   d  show various embodiments of the support  11 . In FIG. 4 a , the cells are circular. In FIG. 4 b , they have a rectangle-triangle shape, the sides  19  and the hypotenuse  21  of which are provided with orifices  20 , which put adjacent cells  18  in communication. In FIG. 4 c , the cells  22  are lozenge-shaped and may be provided with orifices  20  for communication between adjacent cells. In FIG. 4 d , the through-cells or orifices  23  are hexagonal, formed from a honeycomb structure. The walls of the cells  23  may have communication orifices  20 . 
     The composite panel may be manufactured simply, since the adhesive bonding is produced by thermal adhesion and the composite is formed by thermoforming. 
     One or more composite panels may be integrated in the dashboard and/or the roof and/or the parcel shelf of a vehicle and/or the doors. 
     Finally, FIG. 5 shows, as a function of the pressure difference ΔP expressed in Pascal and of the flow rate in m 3 /h, the operating regions for values of R such that R≦180 N.s.m −3  and R≦80 N.s.m8 −3 .