U.S. patent application number 10/466722 was filed with the patent office on 2004-04-15 for silencer with a plurality of resonance chambers.
Invention is credited to Zirkelbach, Thomas.
Application Number | 20040069563 10/466722 |
Document ID | / |
Family ID | 7670911 |
Filed Date | 2004-04-15 |
United States Patent
Application |
20040069563 |
Kind Code |
A1 |
Zirkelbach, Thomas |
April 15, 2004 |
Silencer with a plurality of resonance chambers
Abstract
The invention relates to a sound absorber mounted on or in a
component, wherein a sound which is to be absorbed is propagated.
The silencer comprises a hollow body, which communicates with the
component or forms a component part of the component. A plurality
of Helmholtz resonators which operate in a parallel manner are
arranged behind each other in the axial direction of the hollow
body in at least one axial part of the hollow body.
Inventors: |
Zirkelbach, Thomas;
(Remseck, DE) |
Correspondence
Address: |
WILLIAM COLLARD
COLLARD & ROE, P.C.
1077 NORTHERN BOULEVARD
ROSLYN
NY
11576
US
|
Family ID: |
7670911 |
Appl. No.: |
10/466722 |
Filed: |
July 18, 2003 |
PCT Filed: |
January 15, 2002 |
PCT NO: |
PCT/DE02/00094 |
Current U.S.
Class: |
181/269 |
Current CPC
Class: |
F01N 13/017 20140601;
F02B 37/00 20130101; F02M 35/1216 20130101; F02M 35/1261 20130101;
G10K 11/172 20130101; F01N 1/026 20130101; F01N 13/0097 20140603;
F02M 35/14 20130101; F02M 35/1266 20130101 |
Class at
Publication: |
181/269 |
International
Class: |
F01N 001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2001 |
DE |
101 02 040.6 |
Claims
1. A sound absorber on or in a component (7), in which a sound to
be damped disperses, with a hollow body (8), which communicates
with the component (7) or forms an element of the component (7),
whereby at least in one axial section (9) of the hollow body (8),
multiple, parallel acting Helmholtz resonators (10) are arranged
one after another in an axial direction of the hollow body (8).
2. The sound absorber according to claim 1, characterized in that
in the at least one axial section (9) of the hollow body (8),
multiple, parallel acting Helmholtz resonators (10) are arranged
side by side in a circumferential direction of the hollow body
(8).
3. The sound absorber according to claim 2, characterized in that
in the at least one axial section (9) of the hollow body (8) in a
zone (14) extending in an axial direction and in a circumferential
direction of the hollow body (8), multiple, parallel acting
Helmholtz resonators (10) are arranged in the axial direction of
the hollow body (8) one after another and side by side in the
circumferential direction of the hollow body (8).
4. The sound absorber according to claim 3, characterized in that
the zone (14) encloses the hollow body (8) completely in the
circumferential direction.
5. The sound absorber according to claim 3, characterized in that
two or more zones (14) are distributed on the hollow body (8).
6. The sound absorber according to one of claims 1 through 5,
characterized in that adjacent Helmholtz resonators (10) border one
another.
7. The sound absorber according to claim 6, characterized in that
Helmholtz resonators (10) bordering one another have common walls
or wall sections (10).
8. The sound absorber according to one of claims 1 through 7,
characterized in that the cross sections of the Helmholtz
resonators (10) are smaller than the cross section of the hollow
body (8).
9. The sound absorber according to one of claims 1 through 8,
characterized in that each Helmholtz resonator (10) has a hollow
chamber (11), which communicates with an interior (13) of the
hollow body (8) via a separate connection opening (12).
10. The sound absorber according to claim 9, characterized in that
a distance (17) between Helmholtz resonators (10) adjacent to the
connection openings (12) is smaller than a wavelength or half a
wavelength of a frequency to be damped or smaller than a middle
wave length or half a middle wavelength of a frequency band to be
damped.
11. The sound absorber according to one of claims 1 through 10,
characterized in that each Helmholtz resonator (10) has a hollow
chamber (11), whereby the hollow chambers (11) of multiple
Helmholtz resonators (10) are closed radially outward with a common
cover.
12. The sound absorber accordion one of claims 1 through 11,
characterized in that at least some of the Helmholtz resonators
(10) differ from one another in by having different lengths and/or
cross sections and/or geometries and/or orientations of their
hollow chambers (11) and/or their connection openings.
13. The sound absorber according to one of claims 1 through 12,
characterized in that at least some of the Helmholtz resonators
(10) are arranged parallel to one another.
14. The sound absorber according to one of claims 1 through 13,
characterized in that at least some of the Helmholtz resonators
(10) are arranged radially to a longitudinal axis (15) of the
hollow body (8).
15. The sound absorber according to one of claims 1 through 14,
characterized in that at least some of the Helmholtz resonators are
formed on the hollow body (8), such that a common block containing
the hollow chambers (11) of these Helmholtz resonators (10) is
bordered radially outward by a common cover and radially inward by
a common wall section of the hollow body (8) containing the
connection openings (12) of these Helmholtz resonators (10).
16. The sound absorber according to claim 15, characterized in that
the block has a honeycomb structure.
17. The sound absorber according to one of claims 1 through 16,
characterized in that the hollow body (8) forms a housing or a
housing element of the component (7).
18. The sound absorber according to one of claims 1 through 17,
characterized in that the sound absorber (1) is formed as an
attaching part for attachment to the component (7) or as a mounting
part for installation in the component (7) or as an integrated
element of the component (7).
19. The sound absorber according to one of claims 1 through 18,
characterized in that the component (7) forms an element of a fresh
air tract (4) or an exhaust tract of an internal combustion engine
(2).
20. The sound absorber according to claim 19, characterized in that
the sound absorber (1) is arranged in the fresh air tract (4)
downstream of an air filter (5) and upstream of an exhaust
turbocharger (3) of the internal combustion engine.
21. The sound absorber according to claim 19 or 20, characterized
in that the component is formed by a line (7) or an air filter or
an air accumulator.
22. A use of a sound absorber (1) according to one of claims 1
through 21 on or in an apparatus, which is operated by a combustion
engine or with an electric engine or with compressed air.
23. The use according to claim 22, characterized in that the
apparatus is formed as a motor vehicle or a washing machine or a
dish washer or a clothes dryer or a hair dryer or a vacuum cleaner
or an exhaust air blower or an air intake assembly or a
compressed-air-or electrical motor-operated tool.
24. The use of a sound absorber (1) according to one of claims 1
through 21 for damping sound in the range of relatively high
frequencies, for example, from approximately 900 Hz.
Description
[0001] The invention relates to a sound absorber on or in a
component, in which sound to be absorbed, in particular, airborne
sound, is dispersed.
[0002] Sound absorbers, or mufflers, are used in internal
combustion engines, for example, for reducing noise emissions into
the surrounding environment. For example, mufflers are arranged in
an exhaust tract of an internal combustion engine, in order to
lessen the sound produced and dispersed from the internal
combustion engine. Likewise, in motor vehicles, sound absorbers are
used in the fresh air tract of the internal combustion engine, in
order, for example, to lessen the sound produced by an exhaust
turbocharger in an engine utilizing such a turbocharger and to
lessen the sound dispersed in the fresh air tract.
[0003] For damping sound which is dispersed in a line, so-called
"shunt resonators" or "Helmholtz resonators" are known. Such a
Helmholtz resonator essentially comprises a hollow chamber, which
communicates with the interior of a line via a connection opening,
in which the sound to be damped disperses, whereby the remainder of
hollow chamber is closed. The gas volume enclosed in the hollow
chamber operates thereby as a "spring" and the gas volume in the
connection opening operates as a "mass", whereby a vibratory system
is formed. This vibration system can be stimulated into vibration
by means of sound waves, whereby the sound wave energy is canceled,
that is, the sound is damped. The damping effect of such a
Helmholtz resonator, however, is limited to a predetermined
frequency or to a predetermined frequency band. The frequency or
frequency band with which the Helmholtz resonator utilizes its
damping effect depends, for example, on the geometry, the cross
section, the length, and therefore, the volume of the hollow
chamber, as well as the connection opening of the Helmholtz
resonator. A Helmholtz resonator, then, can best utilize its
damping action if it is positioned on the line, such that its
connection opening communicates accurately with the interior of the
line there, where an antinode of a vertical sound wave of that
frequency has formed, which is to be damped by the Helmholtz
resonator. By the geometry of the line in which the sound is
dispersed, any positions are provided in which a vertical sound
wave can form. The exact position of an antinode can be calculated
with predetermined frequency. In order to achieve an optimal
damping of a predetermined frequency, then, the Helmholtz resonator
must be connected as precisely as possible to the calculated
position on the line. In the frame of large-volume manufacturing,
such as for example, with the production of motor vehicles or motor
vehicle components, generally the precise adherence of a desired
mounting position can be ensured only with a relatively high
expenditure. In addition, the band width of the frequency to be
damped by the sound absorber equipped with a common Helmholtz
resonator is very narrow, so that only peaks of a level of a
predetermined frequency can be absorbed.
[0004] The present invention is concerned with the problem of
providing an embodiment for a sound absorber of the above-described
type, which can be relatively easily mounted and/or can be
integrated, and thereby enables a high quenching action. In
addition, a sound absorber should be provided, which has an
improved quenching action and, in particular, has an increased
broad-band action. In addition, the sound absorber should be able
to be manufactured in a particularly cost-effective manner.
[0005] This problem is solved according to the sound absorber of
the present invention with the features of claim 1.
[0006] The invention relates to the general idea of equipping a
sound absorber with multiple, in particular, with a plurality of
Helmholtz resonators, which are arranged side by side and operate
their sound-absorbing action parallel to one another. By the
arrangement of the Helmholtz resonators in the sound dispersion
direction one after another, the precise positioning of the sound
absorber on or in the component, for example, a line in which the
sound to be damped is dispersed, does not occur, since of the
multiple Helmholtz resonators, at least one is positioned near or
directly on an antinode. Therefore, since no particularly precise
mounting tolerances must be complied with, serial manufacturing or
serial fitting of a component with the sound absorber of the
present invention is facilitated.
[0007] In addition, it has been shown that the sound absorber
equipped with multiple, parallel acting Helmholtz resonators
utilizes a relatively broad-banded damping action, so that the
sound absorber of the present invention offers altogether an
improved damping action. This broad-band action provides, in
particular, a wanted or tolerated irregularity of the individual
Helmholtz resonators, which is provided with their manufacture.
[0008] Of particular advantage is an embodiment, in which in an
axial section of a hollow body of the sound absorber in a zone
extending in the axial direction and in the circumferential
direction of the hollow body, multiple, parallel-acting Helmholtz
resonators are arranged one after another, or consecutively, in the
axial direction and side by side in the circumferential direction.
In this manner, an areal arrangement of a plurality of Helmholtz
resonators on the hollow body is provided, whereby the damping
action or the broad-banded feature additionally is increased.
[0009] A compact structure is provided, then, when adjacent
Helmholtz resonators border one another. One embodiment, in which
the adjacently bordering Helmholtz resonators have common walls or
common wall sections, is advantageous. In this manner, the
manufacture of the Helmholtz resonators is simplified.
[0010] Of particular advantage is an embodiment, in which the cross
sections of the Helmholtz resonators are smaller compared to the
cross section of the hollow body. In this manner, one embodiment is
formed, which can be used also with relatively minimal structural
space because of its compactness. In this regard, it has been shown
that the Helmholtz resonators, based on their large number and in
spite of their minimal dimensions, affect a relatively large
damping action, so that the sound absorber of the present
invention, compared to a common sound absorber, is built to be
smaller, thereby using a sufficient damping action with greater
band widths. In particular, for high or higher frequencies, for
example, approximately 900 Hz, a large damping value can be
achieved with a small sound absorber.
[0011] In order to improve the damping action, in particular, the
broad-band action of the sound absorber of the present invention,
at least some of the Helmholtz resonators can differ from one
another in different lengths and/or cross sections and/or
geometries and/or orientations of their hollow chambers and/or in
their connection openings.
[0012] Particular applications and uses of the sound absorber of
the present invention are provided in claims 22 through 24.
[0013] Further important features and advantages of the invention
are provided in the dependent claims, from the drawings, and from
the associated description with reference to the drawings.
[0014] It is understood that the previously named features and
those features to be described below can be used not only in the
combination provided, but also in other combinations or alone,
without departing from the frame of the present invention.
[0015] Preferred embodiments of the invention are shown in the
drawings and will be described in greater detail in the following
description. Although the following embodiments explain a
particular use of the sound absorber of the present invention with
an internal combustion engine, it is clear that this occurs without
limitation of the generality of the present invention. In
particular, the sound absorber of the present invention can be used
always when airborne sound is produced or transmitted in an
apparatus. In this regard, the sound absorber of the present
invention is suited in particular for use in or on small
apparatuses for damping high or higher frequencies, in particular,
from 900 Hz, based on its compact structure. For example, the sound
absorber of the present invention can be used with household
apparatuses, for example, washing machines, dish washers, hair
dryers, vacuum cleaners, or extractor hoods. Likewise, use with
electrically motorized or compressed-air operated tools is
possible, which work, in particular, with high engine speed. In
addition, the sound absorber of the present invention can be used
with exhaust air blowers, cooling blowers, air intake assemblies,
air conditioners, and computers, in order to damp the frequencies
determined there.
[0016] In the drawings:
[0017] FIG. 1 shows a schematic diagram-type principle illustration
of an internal combustion engine, which is equipped with a sound
absorber of the present invention;
[0018] FIG. 2 shows a longitudinal section through a sound absorber
of the present invention;
[0019] FIG. 3 shows a cross section through a sound absorber of the
present invention; and
[0020] FIG. 4 shows a cross section as in FIG. 3, however, with a
different embodiment.
[0021] According to FIG. 2, a sound absorber 1 can be used with an
internal combustion engine 2, in order to dampen sound there, which
is produced essentially from an exhaust turbocharger 3 of the
combustion engine 2. The sound absorber, or muffler, 1 is arranged
for this purpose in a fresh air tract 4 downstream of an air filter
5 and upstream of a compressor 6 of the exhaust turbocharger 3. In
this regard, the sound absorber 1 is built into a component,
namely, a line 7 of the fresh air tract 4, is flowed-through by the
air transported through the fresh air tract 4 and in this respect,
forms an element of the line 7. The sound produced from the exhaust
turbocharger 3 spreads through the line 7, against the flow
direction and--without a sound absorber 1--would be moved
relatively undamped to the air filter 5 and finally dispersed into
the surrounding environment. By integrating the sound absorber 1
into the line 7, the determined frequency or frequency bands with
reference to sound dispersed in the line 7 can be damped, whereby
the sound emission of the entire assembly can be reduced.
Preferably, the sound absorber 1 is positioned as close as possible
to the sound source whose sounds are to be damped, that is, here,
near the exhaust turbocharger 3. In the embodiment shown, the sound
absorber 1 is arranged on the clean air side, that is, downstream
of the air filter 5; likewise, an arrangement on the crude-air side
is also possible.
[0022] Preferably, the arrangement shown in FIG. 1 is located in a
motor vehicle again, which contains an internal combustion engine
as a driving engine. Likewise, the invention can be used on
stationary internal combustion engines 2. With the embodiment shown
here, essentially the higher-frequency sound at least in selected
frequencies produced from the exhaust turbocharger 3 can be damped.
Likewise, for example, it is also possible with an internal
combustion engine without an exhaust turbocharger to dampen sound
produced by the internal combustion engine or elements thereof, for
example, from valves of the combustion engine 2.
[0023] According to FIG. 2, the sound absorber of the present
invention 1 has a tube-shaped hollow body 8, which forms a
component of the line 7, in which the sound absorber 1 is installed
or integrated. The hollow body 8 can be cylindrically formed, as
shown here. Other forms, for example, with a cone-shaped hollow
body, are likewise possible.
[0024] In an axial section 9 of the hollow body 8, characterized by
a brace, which extends here along the entire hollow body 8, a
plurality of Helmholtz resonators 10 are arranged in an outer side
of the hollow body 8 one after another in the axial direction and
side by side in the circumferential direction. Each of these
Helmholtz resonators 10 has a hollow chamber 11, and each of these
hollow chambers 11 communicates via an individual connection
opening 12 with an interior 13 of the hollow body 8. Generally, the
hollow chambers 11 of the Helmholtz resonators 10 are closed. By
the chosen arrangement of the Helmholtz resonators 10, these act
simultaneously and thus parallel together with the interior 13 of
the hollow chamber 8 or the line 7. It is noteworthy that the
individual Helmholtz resonators 10 are dimensioned relatively small
compared with the line 7, since the cross sections of the Helmholtz
resonators 10 or the hollow chambers 11 are small in comparison to
the cross section of the line 7 or the hollow body 8. Nevertheless,
the sound absorber 1 of the present invention can display a
relatively strong damping action, in particular, with higher
frequencies, for example, from 900 Hz, which is attributed to the
large number of the individual, parallel-acting Helmholtz
resonators 10.
[0025] According to FIG. 3, two zones 14 can be formed in the axial
section 9 of the hollow body 8, in which, respectively, Helmholtz
resonators 10 are formed one after another and side by side. In
this regard, these zones 14 extend only partially along the
circumference of the hollow body 8 and are arranged opposite one
another on the hollow body 8, according to FIG. 3. In contrast,
according to the embodiments of FIGS. 2 and 4, also a single zone
14 can be formed, which extends along the entire circumference of
the hollow body 8 and completely encloses this in the
circumferential direction. Accordingly, also the Helmholtz
resonators 10 are arranged along the entire circumference side by
side on the hollow body 8. Other embodiments also can have more
than two such zones 14.
[0026] While with the embodiment of FIG. 3, the Helmholtz
resonators 10 or their hollow chambers 11 and connection openings
12 are oriented parallel to one another, FIG. 4 shows an
embodiment, in which the Helmholtz resonators 10 or their hollow
chambers 11 and connection openings 12 are oriented radial to a
longitudinal axis 15 of the hollow body 8.
[0027] With the embodiments shown, adjacent Helmholtz resonators 10
border one another. In addition, the bordering Helmholtz resonators
10 have common walls or wall sections 16, whereby their manufacture
is simplified. In this regard, the hollow chambers 11 of the
Helmholtz resonators 10 basically can have any cross section.
However, circular, rectangular, or hexagonal cross sections are
preferred.
[0028] At least some of the Helmholtz resonators 10 can differ from
one another, in that their hollow chambers 11 and/or their
connection openings 12 have different lengths and/or cross sections
and/or geometries and/or orientations. In this regard, the damping
performance, in particular, the broad band action, of the sound
absorber 1 can be affected.
[0029] According to FIGS. 3 and 4, the hollow body 8 has a circular
cross section. It is clear that the hollow body 8 can have
basically any cross section, at least in the area of its axial
section 9, in particular, a rectangular or polygonal cross
section.
[0030] According to FIG. 2, an embodiment is preferred, in which at
least in the axial direction of the hollow body 8, a distance 17
between the connection openings 12 of two adjacent Helmholtz
resonators 10 is smaller than an entire or half wavelength of a
frequency to be damped or smaller than a whole or half middle
wavelength of a frequency band to be damped. By this manner of
construction, with the mounting of the sound absorber 1 of the
present invention, a precise positioning of the sound absorber 1 on
or in the line 7 is attained. As long as the axial section 9
equipped with the Helmholtz resonators 10 is positioned in the area
of a antinode, at least one of the Helmholtz resonators 10 is found
relatively close or exactly at the maximum of the antinode. In this
manner, an optimal damping action for the sound absorber 1 always
can be permitted.
[0031] With a preferred embodiment, the sound absorber 1 of the
present invention can be constructed, such that the hollow chambers
11 of at least some of the Helmholtz resonators 10 are formed in a
common block, which, for example, has a "honeycomb structure". This
block, then, forms a separately manufacturable component, which can
be attached to a wall section of the hollow body 8. This wall
section includes the connection openings 12. By means of a suitable
placement of the block on the wall section provided for this
purpose, each hollow chamber 11 is associated with a separate
connection opening 12. The wall section therefore defines the block
radially inward. Radially outward, the block is defined, for
example, by a common cover, which closes the hollow chambers 11
radially outward. For example, the two zones 14 in the embodiment
of FIG. 3 each can be formed in this manner. In this manner, a type
of housing can be formed on the hollow body 8, in which the
separately manufactured block containing the hollow chamber 11 can
be inserted. By closing this housing with a suitable cover,
simultaneously, the hollow chambers 1 are closed radially outward.
The block can be connected with the wall section of the hollow body
8 and/or with the cover in a suitable manner, in particular,
welded.
[0032] The component, in which the sound to be damped disperses, is
formed in the described embodiment by the line 7. Likewise, other
embodiments are possible, in which the component, in which the
sound to be damped disperses, is formed by another element of the
fresh air tract, for example, by the air filter 5 of by a fresh air
accumulator 18, from which the fresh air is distributed to the
individual cylinders of the internal combustion engine (compare
FIG. 1). Preferably, then, the hollow body of the sound absorber
forms a housing or an element, for example, a housing wall, of the
component. For example, the sound absorber of the present invention
can be formed on or in the cover of an air filter 5. Basically, the
sound absorber can be formed as an attachment part or as a mounting
part. Likewise, it is possible to form the sound absorber as an
integral element of the respective component. For example, the
sound absorber is integrated in the housing of the air filter 5 of
the air accumulator 8.
* * * * *