| 摘要 |
A ventilation device suitable for a vehicle has a housing 10, a housing inlet 11 which can be connected to a blower 13 and a housing outlet 12 which can be connected to an air guide duct 14, two air filters 15, 16 acting in parallel, and a bypass flap 20 operable to allow the air flow from the housing inlet 11 to the housing outlet 12 to either pass through the filter arrangement, or, at least substantially bypass the air filter arrangement in an approximately rectilinear manner 18 between the upper filter edges 151, 161 and the housing wall 101. Preferably the bypass flap 20 in the bypass position extends over and beyond the upper filter edge 151 of the upstream filter as far as the housing wall, thus shutting off an air passage region between the housing wall and the upper filter edge 151 of the upstream filter 15. The filters are offset relative to one another in the air flow direction and are separated by a partition 17 extending from the upper edge 151 of the upstream filter 15 to the lower edge 162 of the downstream filter 16, and a second bypass path 19 is situated below the downstream filter 16. Due to the low degree of air flow deflection within the housing 10 when the bypass flap 20 is in the bypass mode, air flow resistance and undesirable air flow noises may be reduced. The bypass flap 20 may be arranged with a pivot axle 21 situated on the upper edge 161 of the downstream filter which may be at or near its front edge facing the upstream filter 15. The cross-section of the housing wall 102 upstream of the upstream filter 15 may be tapered from the upper filter edge 151 to the lower filter edge 152 to present a more uniformly distributed air flow over the area of the upstream filter 15. Preferably the downstream filter 16 is of a lesser height than the upstream filter 15.
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