U.S. patent application number 10/752826 was filed with the patent office on 2004-08-12 for exhaust silencer.
Invention is credited to Joost, Claudia, Lugger, Johannes.
Application Number | 20040154860 10/752826 |
Document ID | / |
Family ID | 31197668 |
Filed Date | 2004-08-12 |
United States Patent
Application |
20040154860 |
Kind Code |
A1 |
Joost, Claudia ; et
al. |
August 12, 2004 |
Exhaust silencer
Abstract
In order to provide a silencer (100), in particular an exhaust
silencer, for an internal combustion engine, comprising a first
housing (12) with an inlet aperture (E) and an outlet aperture (A),
wherein an exhaust stream flowing into the inlet aperture (E) and
escaping from the outlet aperture (A) is fed via a catalytic
converter element (K), which silencer can be variably used for
various internal combustion engines of different engine
displacement, which silencer achieves low final temperature values,
low sound values, and small pressure fluctuations and in addition
allows a space-saving exhaust-flow guide arrangement through the
silencer, it is proposed that a calming chamber (10) be provided
between an outlet area (30) of the catalytic converter element (K)
and the outlet aperture (A) of the first housing (12).
Inventors: |
Joost, Claudia; (Hamburg,
DE) ; Lugger, Johannes; (Hamburg, DE) |
Correspondence
Address: |
KELLY BAUERSFELD LOWRY & KELLEY, LLP
6320 CANOGA AVENUE
SUITE 1650
WOODLAND HILLS
CA
91367
US
|
Family ID: |
31197668 |
Appl. No.: |
10/752826 |
Filed: |
January 6, 2004 |
Current U.S.
Class: |
181/258 ;
181/231 |
Current CPC
Class: |
F01N 3/08 20130101; F01N
2510/04 20130101; F01N 3/2885 20130101; F01N 1/02 20130101; F01N
1/003 20130101; F01N 1/084 20130101; F01N 13/1888 20130101 |
Class at
Publication: |
181/258 ;
181/231 |
International
Class: |
F01N 003/02; F01N
003/06; F01N 001/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 17, 2003 |
DE |
203 00 769.7 |
Claims
1. A silencer (100), in particular an exhaust silencer, for an
internal combustion engine, comprising a first housing (12) with an
inlet aperture (E) and an outlet aperture (A), wherein an exhaust
stream flowing into the inlet aperture (E) and escaping from the
outlet aperture (A) is fed via a catalytic converter element (K),
characterised in that a calming chamber (10) is provided between an
outlet area (30) of the catalytic converter element (K) and the
outlet aperture (A) of the first housing (12).
2. The silencer according to claim 1, characterised in that the
catalytic converter element (K) comprises a second housing (14)
which is arranged within the first housing (12).
3. The silencer according to claim 1, characterised in that
essentially the calming chamber (10) is formed by a second inside
(20) of the second housing (14), by the outlet area (30) of the
catalytic converter element (K), and by a recess (D) in the first
housing (12).
4. The silencer according to any one of the preceding claims,
characterised in that the second housing (14) comprises at least
one retention plate (H) with a margin (R), whereby a catalytic
converter chamber (KR) is formed between an inlet area (28) and the
retention plate (H) and the second housing (14).
5. The silencer according to any one of the preceding claims,
characterised in that a catalytic converter element (K) is arranged
in the catalytic converter chamber (KR).
6. The silencer according to any one of the preceding claims,
characterised in that the first housing (12) comprises a front
housing shell (32) and a rear housing shell (34).
7. The silencer according to any one of the preceding claims,
characterised in that the second housing (14) is attached to the
front housing shell (32) of the first housing (12).
8. The silencer according to any one of the preceding claims,
characterised in that a guide plate (L) is arranged on the front
housing shell (32).
9. The silencer according to any one of the preceding claims,
characterised in that an insertion slot (S) is formed between the
recess (D) and the guide plate (L).
10. The silencer according to any one of the preceding claims,
characterised in that spark-protection mesh (F) is arrangeable in
the insertion slot (S).
11. The silencer according to any one of the preceding claims,
characterised in that the spark-protection mesh (F), together with
the recess (D), forms a small outlet chamber (44).
12. The silencer according to any one of the preceding claims,
characterised in that the spark-protection mesh (F) is attached by
at least one attachment element (24), in particular by a
self-tapping sheet-metal screw, in the front housing shell
(32).
13. The silencer according to any one of the preceding claims,
characterised in that a cover (B) can be put in place on the front
housing shell (32).
14. The silencer according to any one of the preceding claims,
characterised in that the cover (B) and the front housing shell
(32) together with the spark-protection mesh (F) form a large
outlet chamber (38).
15. The silencer according to any one of the preceding claims,
characterised in that the outlet chamber (38) comprises a fresh-air
aperture (40).
16. The silencer according to any one of the preceding claims,
characterised in that the outlet chamber (38) comprises an outlet
aperture (42).
17. The silencer according to any one of the preceding claims,
characterised in that the first and/or the second housing (12, 14)
can be constructed in a dual-wall version, wherein an air gap
and/or insulation material can be arranged between the walls.
18. The silencer (100) according to any one of the preceding
claims, characterised in that the first and/or the second housing
(12, 14) can be lined with a sound-absorbing material.
19. The silencer according to any one of the preceding claims,
characterised in that an exhaust channel (26) adjoins the inlet
aperture (E).
20. The silencer according to any one of the preceding claims,
characterised in that cooling tubes for a liquid and/or gaseous
medium can be arranged in the calming chamber (10).
Description
[0001] The invention relates to a silencer with the characteristics
mentioned in the precharacterising part of claim 1.
[0002] Exhaust silencers of the generic type are well known. As a
rule, exhaust silencers, most of the time referred to as silencers
only, are used for silencing internal combustion engines. A
particular type of silencer is used for two-stroke motors, in
particular for portable work machinery such as chain saws or the
like.
[0003] From the state of the art, various solutions to this are
already known. DE 37 29 477 C3 discloses a silencer for a chain saw
or the like whose housing, which comprises a separation plane, is
made from at least two deinstallable parts, comprising an inlet as
well as an outlet for exhaust gases escaping from the cylinder of
the internal combustion engine. The silencer is arranged directly
at the exhaust outlet of the internal combustion engine. The
silencer, which comprises two housing halves, is divided into two
chambers by an internal separation wall, with the inner separation
wall being arranged in a plane behind the housing plane so as to be
gas-proof, while the catalytic converter is positioned in an
opening of the separation wall, thus providing a connection between
the separated chambers. In this way it is possible to arrange the
catalytic converter so that it is spaced apart, all around, from
the silencer housing, and to feed all the exhaust gas through the
catalytic converter.
[0004] In a further known printed patent specification, in DE 38 29
668, the particular solution consists of the catalytic converter
being arranged in a hollow body from which an exhaust end pipe
leads to the silencer outlet. In this solution, too, the catalytic
converter is positioned so as to be spaced apart all around from
the silencer housing; it is thus possible to lead all the exhaust
gas through the catalytic converter and at the same time to cool
the exhaust end pipe, using the "cold", untreated exhaust gas.
Mixing of treated and untreated exhaust gas is avoided.
[0005] Published patent specification DE 198 34 822, examined only
as to obvious defects but not as to patentability, shows a solution
similar to that disclosed in DE 37 29 477 described above. In the
interior of the silencer housing, which comprises two housing
shells, an interior wall as well as a catalytic converter element
are provided, with said catalytic converter element being arranged
between the exhaust inlet and the exhaust outlet. In order to
ensure adequate catalytic treatment of the exhaust gases at low gas
back-pressure, a relatively expensive exhaust flow guide
arrangement has been provided. In this arrangement, the incoming
exhaust flow is divided into partial flows, with at least one of
these partial flows being brought into contact with the catalytic
converter element, wherein the partial flows are brought together
and intermixed before they leave the silencer housing.
[0006] Published patent specification DE 25 39 516, examined only
as to obvious defects but not as to patentability, also discloses
an exhaust device for internal combustion engines, in particular
for handheld machines used in agricultural and forestry
applications. At its wall which comprises the exhaust outlet, the
silencer of the respective exhaust system is covered by a second
shell-like wall. Both walls form a cooling channel with a
nozzle-like narrowing and with a subsequent widening which leads to
the open air and which is preferably diffuser-shaped. The exhaust
gases exit in the region of the nozzle-like narrowing and aspirate
cool air by means of an ejector effect.
[0007] The known solutions are associated with a disadvantage in
that the exhaust flow is guided in a complicated path up to the
outlet aperture, while after the exiting from a catalytic converter
element, said exhaust flow is fed to the outlet aperture without
being influenced. As a result of this, inhomogeneous temperatures
of the treated exhaust gas are experienced at the outlet aperture,
as are temperature peaks, which in particular in the higher load
ranges of the internal combustion engine can only be inadequately
prevented. Furthermore, pressure pulsations occur in the region of
the outlet aperture, which pressure pulsations can then no longer
be compensated for.
[0008] It is thus the object of the invention to provide a silencer
comprising an easily-integrable catalytic converter element of the
generic type, which silencer can be variably used for various
internal combustion engines of different engine displacement, which
silencer achieves low final-temperature values, low sound values,
and small pressure fluctuations and in addition allows a
space-saving exhaust-flow guide arrangement through the
silencer.
[0009] According to the invention, this object is met by a silencer
comprising the characteristics disclosed in claim 1.
[0010] By providing a calming chamber between an outlet area of a
catalytic converter element and the outlet aperture from the first
housing, in an advantageous way a relatively homogeneous
temperature of the treated exhaust gas is achieved, and temperature
peaks within the exhaust gas flow are avoided. Any pressure
pulsations of the internal combustion engine, arranged upstream,
are evened out within the calming chamber. The calming chamber also
acts in an advantageous way as a rear silencer arranged downstream
of the catalytic converter element. Furthermore, it is advantageous
if the calming chamber provides the option, when lined with a
corresponding sound-absorbing material, of serving as an absorption
silencer.
[0011] Furthermore, it is possible in an advantageous way to
realise a guide arrangement for the exhaust flow in which
arrangement gas-proof cooling tubes are led through the calming
chamber, with a liquid or gaseous coolant being fed through said
cooling tubes. Advantageously, it is also possible if the calming
chamber comprises a catalytic, a heat-insulating and/or
sound-absorbing coating, so that the calming chamber fulfils
several tasks at the same time.
[0012] In a preferred embodiment of the invention, the catalytic
converter element is arranged in a second housing which is located
within a first housing of the silencer. Essentially, the calming
chamber is formed by a second inside of the second housing, by an
outlet area of the catalytic converter element and by an insert
piece arranged in a recess of the first housing. In this
arrangement, the second housing comprises retention angles by which
the second housing is attached to a front housing shell of the
first housing.
[0013] In a further preferred embodiment of the invention the
second housing comprises at least one retention plate with a
margin, whereby a catalytic converter chamber is formed between an
inlet area to the catalytic converter element and the retention
plate and the second housing. The catalytic converter material is
arranged accordingly in the catalytic converter chamber.
[0014] In a further preferred embodiment of the invention, the
front housing shell comprises a recess, which at the same time
comprises the outlet aperture, with a guide plate being attached to
the surface of said housing shell in the region of the recess. An
insertion slot is formed between the recess and the guide plate,
with spark protection mesh being arrangeable in said insertion
slot.
[0015] Furthermore, it is preferred if on the front housing shell a
cover is arranged which forms an outlet chamber. The outlet chamber
comprises a fresh-air aperture and an outlet aperture.
Advantageously, the fresh-air aperture is used for mixing the
exhaust flow with fresh air. This makes it possible for the
temperature of the gas mixed with fresh air to be lowered to such
an extent that the exhaust gas temperature in an advantageous way,
in the measurement planes specified by registration/approval
regulations, safely remains below the legally permissible maximum
values. The cover can be shaped such that in the flow path of the
treated exhaust gas a narrowing or constriction of the flow channel
results, such that a nozzle effect is achieved. This results in
fresh air being aspirated in the desired quantity in order to
achieve optimal mixing of the treated exhaust gas with fresh
air.
[0016] Further preferred embodiments of the invention result from
the remaining characteristics mentioned in the subordinate
claims.
[0017] Below, the invention is explained in more detail by means of
the associated drawings with reference to an exemplary embodiment.
The following are shown:
[0018] FIG. 1 a perspective view of an exhaust silencer; and
[0019] FIG. 2 a section of the exhaust silencer according to Line
A-A in FIG. 1.
[0020] FIG. 1 shows an exhaust silencer 100, hereinafter referred
to as a silencer. This perspective view essentially shows a front
housing shell 32 and a rear housing shell 34 of the first housing
12. The front housing shell 32 comprises a cover 3 which comprises
an outlet aperture 42. FIG. 1 further shows a mounting device 44
which is used to connect the silencer 100 to an internal combustion
engine.
[0021] The further elements according to the invention are shown in
FIG. 2 (section A-A in FIG. 1 of the silencer 100 without mounting
device 44). Shown again are the front housing shell 32 and the rear
housing shell 34 which form the first housing 12 of the silencer
100. The first housing 12 comprises a first inside 16 of the
housing and a first outside 18 of the housing. The first housing 12
comprises an inlet aperture E which leads to an exhaust channel 26.
The inlet aperture E is connected to an internal combustion engine
such that the exhaust gas to be treated enters the silencer 100
without there being any loss. The exhaust gas to be treated is fed
to the first housing 12 by way of the exhaust channel 26. In the
interior of the first housing 12 of the silencer 100, in the front
housing shell 32 which is preferably removable, there is a second
housing 14 into which the catalytic converter element K is placed.
The second housing 14 is referred to as the accommodation housing
because it accommodates the catalytic converter element K. By means
of a retention plate H with an encompassing margin R in the
accommodation housing 14, the catalytic converter element K is
attached, at corresponding preliminary tension, to a second inside
20 of the accommodation housing 14. The first inside 16 of the
first housing 12, together with a second outside 22 of the
accommodation housing 14, forms the space in front of the catalytic
converter element K.
[0022] Preferably, the retention plate H is attached to the second
inside 20 of the accommodation housing 14. A catalytic converter
chamber KR is formed between the accommodation housing 14 and the
retention plate H, with the catalytic converter element K being
located in said catalytic converter chamber KR. Furthermore, the
accommodation housing 14 comprises an inlet area 28 into the
catalytic converter element K, and an outlet area 30 from the
catalytic converter element K.
[0023] If, depending on the size of the displacement of the
internal combustion engine arranged upstream, different sizes of
catalytic converters are used or required, the retention plate H is
attached at different locations in the accommodation housing 14.
This provides the option in a particularly advantageous way of
using the silencer 100 for internal combustion engines of different
displacement, which engines, as a result of this, require different
sizes of catalytic converter elements. As a result of this
adaptability, the catalytic converter element K is always safely
retained in the accommodation housing 14. It must be ensured that,
with a view to meeting the prescribed exhaust emission
requirements, the smallest-possible catalytic converter element K
is used, since this is a relatively expensive and heavy
component.
[0024] The front housing shell 32 comprises a recess D with an
outlet aperture A, wherein this outlet aperture A can be configured
using different diameters so as to ensure optimal adaptation to the
exhaust-gas back-pressure.
[0025] However, before the exhaust gas to be treated flows through
the outlet aperture A, according to the invention the exhaust flow
is fed to a calming chamber 10. Essentially, the calming chamber 10
is formed by the second inside 20 of the accommodation housing 14,
by the outlet area 30 of the catalytic converter element K, and by
the recess D of the front housing shell 32.
[0026] The accommodation housing 14 is attached to the front
housing shell 32. As an alternative, the second inside 20 of the
accommodation housing 14, which accommodation housing delimits the
calming chamber 10 and behind which housing the retention plate H,
of which there is at least one, accommodates the catalytic
converter element K, can also be constructed in a dual-wall version
so that between the housing walls, an air gap is formed as a
temperature insulation, sound insulation and/or noise-insulation
gap. Optionally, corresponding insulation material can be used.
[0027] Adjacent to the calming chamber 10 is a small and a large
outlet chamber 44, 38 which is partitioned by spark-protection mesh
F to form said small and large outlet chambers 44, 38.
[0028] The small outlet chamber 44 is formed by the recess D, the
front housing shell 32, and the spark-protection mesh F. The large
outlet chamber 38 is formed by the spark-protection mesh F and the
cover B.
[0029] For the purpose of mounting the spark-protection mesh F, a
guide plate L is attached to the front housing shell 32. Together
with the recess D, an insertion slot S is formed, into which the
spark-protection mesh F can be slid into place. The
spark-protection mesh F is additionally secured to the front
housing shell 32 by means of an attachment element 24, preferably a
self-tapping sheet-metal screw. Installing the spark-protection
mesh F prevents any possibility of secondary reactions between the
exhaust flow and the outside air which is rich in oxygen, thus
safely preventing any emission of sparks or shooting flames.
[0030] As has already been mentioned above, the outlet chamber 38,
which has been formed on the outside, is covered by cover B. In
addition, mixing of the emanating treated exhaust gas with supplied
fresh air takes place in this outlet chamber 38, with said fresh
air being able to be fed through a fresh-air aperture 40,
preferably in the upper region of the cover B.
[0031] The described design of the silencer 100 comprising a first
housing 12 and an accommodation housing 14, in which a catalytic
converter element K is accommodated, and the calming chamber 10
arranged between the first housing 12 and the accommodation housing
14, not only makes possible variable use of catalytic converter
elements K for various internal combustion engines of different
displacement, but also ensures the ability to maintain low final
temperature values, low sound values, and small pressure
fluctuations, while the exhaust gas travels only a short distance
through the silencer 100.
LIST OF REFERENCE CHARACTERS
[0032] 100 Exhaust silencer (silencer)
[0033] 10 Calming chamber
[0034] 12 First housing
[0035] 14 Second housing (accommodation housing)
[0036] 16 First inside of the housing
[0037] 18 First outside of the housing
[0038] 20 Second inside of the housing (accommodation housing)
[0039] 22 Second outside of the housing (accommodation housing)
[0040] 24 Attachment element (self-tapping sheet-metal screw)
[0041] 26 Exhaust channel
[0042] 28 Inlet area of catalytic converter element
[0043] 30 Outlet area of catalytic converter element
[0044] 32 Front housing shell
[0045] 34 Rear housing shell
[0046] 38 Large outlet chamber
[0047] 40 Fresh-air aperture
[0048] 42 Outlet aperture
[0049] 44 Small outlet chamber
[0050] K Catalytic converter element
[0051] H Retention plate
[0052] R Margin
[0053] KR Catalytic converter chamber
[0054] A Outlet aperture
[0055] E Inlet aperture
[0056] D Recess
[0057] F Spark-protection mesh
[0058] B Cover
[0059] L Guide plate
[0060] S Insertion slot
* * * * *