U.S. patent application number 11/923273 was filed with the patent office on 2008-08-28 for ventilation system with sound barrier.
Invention is credited to Ralph Stroehla.
Application Number | 20080207111 11/923273 |
Document ID | / |
Family ID | 38666987 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080207111 |
Kind Code |
A1 |
Stroehla; Ralph |
August 28, 2008 |
Ventilation System With Sound Barrier
Abstract
The invention relates to a noise-optimized ventilation system
(100) which can in particular be integrated into a vehicle, with
the ventilation system (100) having at least one heat exchanger (1)
and a fan (2) for acting on an air guiding volume (3) with an air
flow (7), wherein the air guiding volume (3) has at least one inlet
(4), an outlet (5) and a sound barrier (6).
Inventors: |
Stroehla; Ralph; (Coburg,
DE) |
Correspondence
Address: |
HOWARD & HOWARD ATTORNEYS, P.C.
THE PINEHURST OFFICE CENTER, SUITE #101, 39400 WOODWARD AVENUE
BLOOMFIELD HILLS
MI
48304-5151
US
|
Family ID: |
38666987 |
Appl. No.: |
11/923273 |
Filed: |
October 24, 2007 |
Current U.S.
Class: |
454/262 |
Current CPC
Class: |
B60H 2001/006 20130101;
F24F 2013/245 20130101; F04D 29/44 20130101; F04D 29/665 20130101;
B60H 1/00564 20130101 |
Class at
Publication: |
454/262 |
International
Class: |
F24F 13/24 20060101
F24F013/24 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 25, 2006 |
DE |
102006050339.2 |
Claims
1. A ventilation system (100) comprising at least one heat
exchanger (1) and at least one fan (2) for acting on an air guiding
volume (3), with the air guiding volume (3) having at least one
inlet (4), an outlet (5) and a sound barrier (6), wherein the sound
barrier (6) is an element which reduces the propagation of sound
substantially by means of reflection.
2. A ventilation system (100) according to claim 1, wherein the
sound barrier (6) is connected at least to one wall face of the air
guiding volume (3).
3. A ventilation system (100) according to claim 1, wherein the
sound barrier (6) is arranged substantially perpendicular to the
flow direction of the medium (7) which is set in motion by the fan
(2).
4. A ventilation system (100) according to claim 1, wherein the
sound barrier (6) is embodied as a beam structure.
5. A ventilation system (100) according to claim 1, wherein the
heat exchanger (1) is situated between the fan (2) and the sound
barrier (6).
6. A ventilation system (100) according to claim 1, wherein the
spacing between the heat exchanger (1) and the sound barrier (6) is
in the range from 2 mm to 150 mm.
7. A ventilation system (100) according to claim 1, wherein the
cross section, which is exposed to flow, of the sound barrier (6)
is in the range from 10% to 30% of the cross section of the heat
exchanger (1).
8. A ventilation system (100) according to claim 1, wherein the
flow cross section (8), which is reduced by the integration of the
sound barrier (6), of the air guiding volume (3) is greater than or
equal to the remaining flow cross section (9), which is situated
downstream of the sound barrier (6), of the air guiding volume
(3).
9. A ventilation system (100) according to claim 1, wherein the
flow cross section in the air guiding volume (3) is abruptly
reduced in size downstream of the heat exchanger (1).
10. A ventilation system (100) according claim 1, wherein the cross
section of the inlet (4) is greater than or equal to the cross
section of the outlet (5).
11. A ventilation system (100) according to claim 1, wherein the
air guiding volume (3) and/or the sound barrier (6) are formed from
plastic.
12. A ventilation system (100) according to claim 1, wherein the
air guiding volume (3) and the sound barrier (6) are produced in an
integral construction.
13. A ventilation system (100) according to claim 1, wherein at
least a part of the air guiding volume (3) is formed in an integral
construction, with at least a part of at least one sound barrier
(6).
14. A ventilation system (100) according to claim 2, wherein the
sound barrier (6) is arranged substantially perpendicular to the
flow direction of the medium (7) which is set in motion by the fan
(2).
15. A ventilation system (100) according to claim 2, wherein the
sound barrier (6) is embodied as a beam structure.
16. A ventilation system (100) according to claim 3, wherein the
sound barrier (6) is embodied as a beam structure.
17. A ventilation system (100) according to claim 14, wherein the
sound barrier (6) is embodied as a beam structure.
18. A ventilation system (100) according to claim 6, wherein the
spacing between the heat exchanger (1) and the sound barrier (6) is
in the range from 10 mm to 80 mm.
19. A ventilation system (100) according to claim 7, wherein the
cross section, which is exposed to flow, of the sound barrier (6)
is 17% of the cross section of the heat exchanger (1).
20. A ventilation system (100) according to claim 11, wherein the
plastic is polypropylene (PP) or polyamide (PA).
Description
[0001] The invention relates to a reduced-noise ventilation system,
as is used for example for the ventilation of a vehicle, that is to
say of a vehicle interior space, for the air conditioning
thereof.
[0002] The sound waves, that is to say noise generated for example
by fans of heating, ventilation and air conditioning systems (HVAC
systems) of motor vehicles passes via corresponding ducts with the
air-conditioned air which has been set in motion into a vehicle
interior space, and in doing so adversely affects the driving
experience of the occupants and therefore the comfort. Primarily
high-frequency noise, preferably in the range from 900 Hz to 1400
Hz, is disturbing, irritating or even detrimental to health at a
corresponding volume, that is to say at a corresponding acoustic
pressure level.
[0003] Already-existing solutions for noise or sound reduction
which represent the prior art are briefly explained, and their
characterizing features analysed, interpreted and evaluated,
below.
[0004] In order to reduce or avoid the transmission of noise or
sound, sound dampers are for example known which either absorb
and/or reflect the noise. A well-known embodiment of such a device
for reducing the intensity of sound waves is for example a silencer
in a motor vehicle which reduces the exhaust gas or combustion
noise of the engine within the exhaust system.
[0005] As already indicated, use is generally made of absorption
noise dampers or reflection, that is to say interference noise
dampers. In the case of absorption noise dampers, the strategy for
reducing the intensity of the sound is that according to which
porous material is provided which absorbs the sound and therefore
converts said sound by means of friction into heat. The reduction
of the acoustic pressure by means of the effect of absorption is
often intensified here by means of multiple reflection. Absorption
permits primarily the damping of high-frequency components of a
noise.
[0006] In a reflection sound damper, primarily the lower frequency
components of a noise are damped by the principle of reflection. A
sound damper of such a generic type contains a plurality of
chambers which are traversed multiple times by a flowing medium.
This results in averaging of the sound amplitude, which causes the
depletion of acoustic pressure peaks.
[0007] A further possibility for damping or preventing the
propagation of noise is sound control walls. Here, it is attempted
to reduce the sound directly at, that is to say in the direct
vicinity of, the noise source.
[0008] FR 2 780 347 describes a plastic housing for a heating and
air conditioning system of a motor vehicle whose walls are provided
with absorption devices or means for reducing flow noises. The air
flow generated by a turbine or ventilator which is situated in a
spiral, that is to say worm housing is guided here laterally to the
air inlet of the housing. Situated downstream (in the direction of
the flowing fluid) in the inlet region or air inlet duct of the
housing are an air filter and an evaporator. The air which flows
out of the evaporator can be conducted by means of two flaps into a
duct for cold, fresh air and/or a duct for warm air, with a further
heat exchanger, which functions as a heater, being situated in the
duct for warm air. After leaving the ducts, the air flows of the
air flow which has possibly been split up by the flaps are mixed in
a common chamber within the housing, specifically in such a way
that a desired temperature of the air is obtained. The air is
subsequently conducted downstream to its respective destination by
means of corresponding flaps and ducts. Measures for reducing the
noises generated or transmitted by the flowing air are realized
here in that the absorption means of the housing are designed as
Helmholtz resonators. Here, the Helmholtz resonators are air-filled
or foam-filled chambers which are connected by means of openings to
the air ducts of the housing.
[0009] The air flow and associated noise propagation is influenced
here in a fluid-mechanical manner, that is to say by means of a
fluid-fluid interaction and not by means of a fluid-structure
interaction. As a result of the arrangement of a plurality of
Helmholtz resonators on or outside the housing, the construction or
the overall structure is very complex and requires additional
installation space, that is to say it is not possible to obtain a
compact design of the housing while correspondingly having noise
reduction taking place at the same time by means of absorption.
Losses occurring as a result of deflection and friction are
therefore very high, which reduces efficiency.
[0010] JP 07 228128 A describes a housing having a fan, with an
additional chamber, which serves as a resonance chamber or sound
damper, being arranged at or in the vicinity of the fan.
[0011] U.S. Pat. No. 2,225,398 A proposes a double-walled, radially
running fan housing having chambers or cells, with openings being
provided in the wall on the inside of the housing in the region of
said cells in order to obtain a resonator action, that is to say
sound absorption. Here, the cells are filled either with air or a
sound-absorbing material.
[0012] JP 62 218743 A discloses a housing which is provided, via
openings in flow-guiding walls which are situated downstream of the
fan wheel, with Helmholtz resonators in the form of chambers. Here,
the openings to the chambers are covered or provided with thin
diaphragms.
[0013] EP 0 800 030 A1 describes a flap, which is composed of two
flap parts, for an air guiding duct. The flap is formed from
plastic material and has, at the side which is assigned to an
approaching air flow, openings in order to function as a Helmholtz
resonator for noise damping in the air guiding duct. In addition,
the flap has, in the region of the openings, a damping layer formed
from a porous material in order to increase the flow resistance and
additionally dampen the sound. It is possible by means of
integrated partitions within the flap to realize Helmholtz
resonators for different frequencies. Here, the flap serves on the
one hand for controlling the air flow and on the other hand for
damping the propagating noise by means of absorption.
[0014] The abovementioned solutions for reducing the sound emission
or acoustic power level have the disadvantage that they are on the
one hand very voluminous, that is to say require a relatively large
amount of installation space, which has a highly adverse effect for
example in the case of integration into a vehicle. In addition,
such correspondingly described noise damper systems have the
disadvantage that they lead to undesired turbulence and therefore
to an increased resistance with regard to the flowing fluid, which
is noticeable for example as a pressure drop and possibly demands
further noise-generating devices. In addition, corresponding
systems which represent the prior art are associated with high
investment and servicing costs. A further disadvantage is that
noise dampers of said type for use in ventilation systems, in
particular absorption noise dampers, often also have problems with
regard to odours.
[0015] Against the background of the prior art, the object of the
present invention is that of specifying a ventilation system which
is optimized with regard to noise while avoiding the stated
disadvantages and therefore offers optimum acoustic comfort for
example for a vehicle interior space of a vehicle.
[0016] Said object is achieved by means of the features of
independent patent Claim 1, with expedient embodiments being
described by the features of the dependent claims.
[0017] According to the invention, therefore, a noise optimized
ventilation system is provided which can advantageously be used for
or integrated in vehicles, since it for example requires little
installation space. Here, within the context of air conditioning
for one space, the ventilation system has at least one heat
exchanger, with the heat exchanger preferably being embodied as an
evaporator. In addition, the ventilation system according to the
invention has at least one flow machine in the form of a fan which
is provided for acting on an air guiding volume. Here, the air
guiding volume has at least one inlet and at least one outlet, and
at least one sound barrier. In a ventilation system of said type,
the fan sets air in motion, which air flows inter alia through the
air guiding volume and is discharged via the outlet of the air
guiding volume into the interior space of a vehicle. The noise or
sound, as a propagation of pressure and density fluctuations in an
elastic medium such as for example air, caused by the flow machine,
that is to say the fan, is prevented here by the sound barrier from
passing into a vehicle interior space, which is connected to the
ventilation system or the air guiding volume, of a vehicle. Here,
the sound barrier is a device or element which reduces the
propagation of sound substantially by means of reflection of the
sound. It is primarily possible, by means of reflection of the
sound to surrounding walls of the air guiding volume which is
caused by a sound barrier of such design, for the high-frequency
component of the sound, for example in the range from 900 Hz to
1400 Hz, to be reduced.
[0018] It is advantageously possible in such an embodiment of the
ventilation system for the sound emission level, as an acoustic
power level measured in decibels, to be partially reduced by 6
dB(A) to 8 dB(A), which, when considering the overall system, with
regard to the noise produced by the vehicle which can be perceived
in the interior space, is noticeable in that the total sound
emission level is reduced by 2 dB(A).
[0019] The sound barrier is preferably connected at least to one
wall face of the air guiding volume. It is thereby possible,
primarily with regard to the flowing medium, that is to say the
air, to obtain favourable flow conditions, and there are no air
quantity losses. Here, flow advantageously passes around the sound
barrier, and therefore separates the flow cross section of the air
guiding volume into at least two cross sections or regions.
[0020] The sound barrier is advantageously arranged substantially
perpendicular to the flow direction of the medium which is set in
motion by the flow machine or the fan. It is thereby possible to
obtain a high efficiency of the sound barrier with regard to the
sound reduction without having to accept large flow losses.
[0021] The sound barrier is preferably embodied as a beam
structure. A beam structure is simple to produce and can be quickly
integrated into a corresponding air guiding volume. Edges around
which the medium which is set in motion by the fan flows are
advantageously rounded off, such that turbulence vortices in the
air flow can be reduced or entirely eliminated. Vortices of said
type would increase the resistance to the following flow of the
flowing medium, and this would lead to a pressure drop or to a
reduced air quantity throughput.
[0022] The heat exchanger is advantageously situated between the
fan and the sound barrier. As a result of an arrangement of said
type, in which the heat exchanger is arranged, with respect to the
medium which is set in motion by the fan, downstream in the
direction of the flowing medium between the fan and the sound
barrier, a ventilation system of such design according to the
invention can be installed for example into a vehicle and can be
serviced quickly, easily and with the smallest possible
installation space requirements. It would of course also be
conceivable to integrate the heat exchanger upstream of the fan, in
the opposite direction to the flow direction of the flowing medium,
that is to say in the suction region of the fan.
[0023] The spacing between the heat exchanger and the sound barrier
is preferably in the range from 2 mm to 150 mm, in particular
preferably in the range from 10 mm to 80 mm. An advantage which
results from this is that the relatively large flow cross section
behind, that is to say downstream of a heat exchanger can be
correspondingly utilized, and inhomogeneous flow conditions in the
heat exchanger can be avoided.
[0024] The flow cross section, which is reduced by the integration
of the sound barrier, of the air guiding volume is always greater
than or equal to the remaining flow cross section, which is
situated downstream of the sound barrier, of the air guiding
volume. This gives a favourable boundary condition for the flow of
the medium for ventilation, which therefore has little influence
within the context of a resistance on the air flow which is
generated by the fan, and would therefore result in air quantity
losses.
[0025] The flow cross section in the air guiding volume is
preferably abruptly reduced in size downstream of the heat
exchanger, that is to say towards the outlet of the air guiding
volume. This results in the advantage that it is possible to cope
primarily with limited or predefined installation space, which is
given for example in motor vehicles.
[0026] The cross section of the inlet of the air guiding volume is
preferably greater than or equal to the cross section of the
outlet. In this way, it is additionally possible to obtain a
further noise reduction primarily by means of reflection.
[0027] The air guiding volume and/or the sound barrier are
preferably formed from plastic, preferably from polypropylene (PP)
or polyamide (PA). This results in the advantages of for example a
simple and cost-effective production process, for example by means
of injection moulding, and a considerably reduced weight.
[0028] The air guiding volume and the sound barrier are preferably
produced in an integral construction. In this way, primarily a
simple production process and simple assembly can be realized.
[0029] At least a part of the air guiding volume and at least a
part of the at least one sound barrier are preferably formed in an
integral construction, preferably by means of an injection moulding
process. For example, in each case one part of the sound barrier
could be integrally formed with in each case one component of the
housing or air guiding volume, as a result of which the sound
barrier is formed as the housing parts are joined together, in
particular as a closed structure. Advantages are given here
primarily in production and assembly.
[0030] The cross section which is exposed to flow, that is to say
the cross-sectional area, which is exposed to flow, of the sound
barrier is advantageously in a range from 10% to 30% of the cross
section of the heat exchanger or evaporator. The cross-sectional
area, which is exposed to flow, of the sound barrier is
particularly advantageously 17% of the cross-sectional area of the
heat exchanger.
[0031] The disclosed features of the ventilation system according
to the invention can of course be varied within the scope of the
claims and combined with one another in any desired manner in order
to obtain further advantages and properties.
[0032] The invention therefore relates to a ventilation system
which is characterized primarily by the advantages of the sound
barrier which is integrated into the air guiding volume.
[0033] Further properties and advantages of the invention can be
gathered from the following description of embodiments of the
invention, with reference to the appended figures, which
embodiments are however to be understood merely as exemplary and in
no way restrictive.
[0034] In the figures:
[0035] FIG. 1 shows a cross section through an exemplary embodiment
of a ventilation system 100 according to the invention;
[0036] FIG. 2 is a graphic illustration of the flow cross-sectional
profile or the flow cross-sectional profiles in the air guiding
volume 3 of the exemplary embodiment of a ventilation system 100
according to the invention shown in FIG. 1;
[0037] FIG. 3 shows a detail of an exemplary embodiment of a
ventilation system 100 according to the invention in a motor
vehicle in a perspective, three-dimensional illustration.
[0038] FIG. 1 shows a cross section through an exemplary embodiment
of a ventilation system 100 according to the invention with
components which are illustrated in a partially simplified manner
and which will be explained in more detail below. The ventilation
system 100 according to the invention is, in the exemplary
embodiment shown, integrated or installed in a motor vehicle (not
illustrated in FIG. 1) and serves for the ventilation or air
conditioning of the vehicle interior space (not illustrated in FIG.
1).
[0039] Accordingly, FIG. 1 illustrates a heat exchanger device
which functions as an evaporator 1. Air 7 which flows or moves
through the evaporator 1 or the plates of the evaporator is
correspondingly cooled because a refrigerant in the evaporator 1
requires heat energy in order to be able to evaporate. Said heat
energy is therefore extracted from the air 7 via the surface of the
evaporator 1.
[0040] Also shown is the housing of a fan 2 which is situated in
the direct vicinity, that is to say at a side of the evaporator 1
and is provided for setting air 7 in motion. Here, the fan 2 is
designed as a radial ventilator, Here, the air 7 is sucked in by
the fan 2. After the air 7 passes out of the fan 2 on that side 2a
of the fan 2 which faces towards the evaporator 1, the evaporator 1
is therefore acted on or traversed by the air 7, with the air 7
which is provided for the air conditioning being cooled as it
passes through the evaporator 1, as already described.
[0041] In addition, in the exemplary embodiment of a ventilation
system 100 according to the invention which is shown, an air
guiding volume 3 is arranged or connected at the opposite side 1a
of the evaporator 1 from the fan 2. The air guiding volume 3 has,
in the exemplary embodiment of a ventilation system 100 according
to the invention which is shown, an inlet 4 which is connected or
joined to the opposite side 1a of the evaporator 1 from the fan 2.
In addition, in the exemplary embodiment shown, the air guiding
volume 3 has an outlet 5 which is connected to the vehicle interior
space, which is to be ventilated or air-conditioned, of the vehicle
(not illustrated in FIG. 1). Here, the air guiding volume 3 is
advantageously formed from plastic, such as for example
polypropylene (PP). Also conceivable would be a design of the air
guiding volume 3 made from polyamide (PA).
[0042] As can be seen from FIG. 1, the air guiding volume 3 is
acted on with air 7 by the fan 2 via the evaporator 1, that is to
say the air 7 which emerges from the evaporator 1 passes via the
inlet 4 of the air guiding volume 3 into the air guiding volume 3
and flows through the air guiding volume 3 to the outlet 5 of the
air guiding volume 3 into the connected vehicle interior space (not
illustrated in FIG. 1), which has already been discussed, in order
to correspondingly ventilate or provide air conditioning in said
vehicle interior space.
[0043] As can be seen from FIG. 1, the embodiment of a ventilation
system 100 according to the invention which is shown advantageously
has two sound barriers 6 (6a, 6b) which are situated in the air
guiding volume 3 between the inlet 4 of the air guiding volume 3
and the outlet 5 of the air guiding volume 3. Here, the sound
barriers 6 are designed substantially as beam structures, that is
to say as transverse beams, and are arranged substantially
perpendicularly with respect to the flow direction of the flowing
air 7. Like the air guiding volume 3, a design of the sound
barriers 6a, 6b from plastic is advantageous since for example
weight can be saved. In the exemplary embodiment of a ventilation
system 100 according to the invention which is shown, the sound
barriers 6a, 6b preferably have, in cross section, rounded edges
around or over which the air 7 flows. As a result of such a design
of the sound barriers 6a, 6b with rounded edges, for example vortex
formation in the flowing air 7 is avoided or prevented, which would
lead to an increase in the resistance to the flow of the air 7, a
pressure drop downstream, that is to say in the direction of the
flowing air 7, and therefore to a reduced efficiency of the
ventilation system.
[0044] In contrast to the sound barrier 6b, the sound barrier 6a is
arranged in a free-lying or free-standing manner. In other words,
the air 7 which is set in motion flows completely around the
surfaces of the sound barrier 6a with the exception of the
connecting regions of the sound barrier 6a to the inner wall of the
air guiding volume 3, while the sound barrier 6b is on one side
situated on or connected to the wall face of the air guiding volume
3.
[0045] The main noise source in the ventilation system 100 is the
fan 2. The sound waves generated by the fan 2, as small pressure
and density fluctuations in an elastic medium, propagate
longitudinally and/or transversely with the air 7 which is set in
motion by the fan 2 and would, in passing through the evaporator 1,
pass with the air 7 via the air guiding volume 3 which is connected
to the evaporator 1 into the vehicle interior space (not
illustrated in FIG. 1) and therefore restrict the desired comfort,
or have a disturbing and irritating effect for the occupants of the
vehicle interior space.
[0046] However, the integration of the sound barriers 6a, 6b in the
exemplary embodiment of a ventilation system 100 according to the
invention which is shown in FIG. 1 prevents or reduces the noise
propagation, so as to give a noise-optimized ventilation system 100
having the already-stated and highlighted advantages.
[0047] By means of sound barriers 6a, 6b which are arranged and
designed in such a way, the propagation of the sound with the
high-frequency components, for example in the range from 900 Hz to
1400 Hz, is suppressed or prevented primarily by means of
reflection effects of the sound barriers 6a, 6b with the inner
walls, that is to say the wall faces of the air guiding volume 3.
There is an associated advantageous partial reduction of the sound
emission level in said frequency range by 6 dB(A) to 8 dB(A).
[0048] Here, the sound barriers 6a, 6b are advantageously to be
arranged in the region of a cross-sectional step of the flow cross
section which is provided by the air guiding volume 3. There are
therefore no losses in the quantity of the flowing air 7 in said
region, and there is no risk of vortex formation or an associated
deterioration in the operation of the ventilation system 100
according to the invention.
[0049] FIG. 2 shows, in a graphic illustration, a flow
cross-sectional profile or flow cross-sectional profiles in the air
guiding volume 3 for the air 7 which flows through the air guiding
volume 3, which air 7 enters at the inlet 4, flows along the air
guiding volume 3 and exits at the outlet 5. Here, the air guiding
volume 3 or the flow cross section which is provided by the air
guiding volume 3 corresponds to the air guiding volume 3 shown in
FIG. 1 with the integrated sound barriers 6a and 6b of the
exemplary embodiment of a ventilation system 100 according to the
invention.
[0050] It can be clearly seen that the cross section at the inlet 4
of the air guiding volume 3 is significantly larger than the cross
section at the outlet 5 of the air guiding volume 3. In addition,
for the region in which the sound barriers 6a and 6b are situated
in the air guiding volume 3, there is a division, which takes place
correspondingly in sections, of the flow of the air 7 which is set
in motion by the fan 2, and therefore of the flow cross section of
the air guiding volume 3. The cause of this is the
already-described position of the sound barrier 6a in the air
guiding volume 3 of the exemplary embodiment of a ventilation
system 100 according to the invention which is shown in FIG. 1. In
the further profile downstream, that is to say in the direction of
the flowing air 7, however, the flow of the air 7 which is divided
into two flows by the sound barrier 6a is merged again in the air
guiding volume 3. Consequently, there is also an associated return
from two flow cross sections to a single flow cross section in the
air guiding volume 3 downstream of the sound barrier 6a.
[0051] FIG. 3 shows a detail of an exemplary embodiment of a
ventilation system 100 according to the invention, which is
integrated within an air-conditioning system region of a motor
vehicle, in a perspective, three-dimensional illustration. A fan 2,
of which the housing 2 can be seen, serves for acting on the air
guiding volume 3, or the heat exchanger 1 which functions as an
evaporator 1, in order to heat and/or cool the air 7.
[0052] In an installation of said type, the fan 2 is preferably
capable of sucking in external air and/or recirculated air from the
vehicle interior space and feeding or accelerating the air flow 7
with a pressure loading. After leaving the fan 2, the air 7 which
is set in motion passes through the evaporator 1 and passes, having
been correspondingly heated or cooled, via the inlet 4 (not
illustrated in FIG. 3) into the inlet region of the air guiding
volume 3 which is connected to the evaporator 1 downstream. The
sound-reducing means, that is to say sound barriers 6 in the form
of closed beams, are preferably situated in the air guiding volume
3 in the direct vicinity of the evaporator 2. As shown in FIG. 3,
in the exemplary embodiment of the ventilation system 100 according
to the invention, the sound barrier 6a does not extend over the
entire width of the air guiding volume 3 but rather advantageously
projects, in an arrangement lying transversely with respect to the
evaporator 2 or the flowing air 7 which emerges from the
evaporator, up to a certain region into the flow cross section of
the air guiding volume 3. In the exemplary embodiment of a
ventilation system 100 according to the invention which is shown, a
further sound barrier 6b is provided within the air guiding volume
3. Said further sound barrier 6b is situated, in a flow-promoting
and sound-reduction-promoting position, downstream of the sound
barrier 6a, with one side of the sound barrier 6b bearing against
one of the side walls of the air guiding volume 3. The noises which
are transported with the moving air 7 are correspondingly reflected
on the sound barriers 6a and 6b, such that there is a reduced sound
emission. The air 7 which is set in motion by the fan 2 therefore
passes via the outlet 5 of the air guiding volume 3 with a
considerably reduced acoustic amplitude into the passenger
compartment and leads to optimum noise comfort.
[0053] In summary, it is to be stated that the invention is based
on providing a ventilation system which is optimized with regard to
noise generation and which, by means of the integration of at least
one sound barrier into the air guiding volume, primarily prevents
the emergence of high-frequency sound out of the ventilation
system.
* * * * *