U.S. patent application number 11/834270 was filed with the patent office on 2008-03-06 for exhaust device with a flame resonator.
This patent application is currently assigned to DOLMAR GMBH. Invention is credited to Christian Kellermann, Henning Schweinberger.
Application Number | 20080053076 11/834270 |
Document ID | / |
Family ID | 38885343 |
Filed Date | 2008-03-06 |
United States Patent
Application |
20080053076 |
Kind Code |
A1 |
Kellermann; Christian ; et
al. |
March 6, 2008 |
EXHAUST DEVICE WITH A FLAME RESONATOR
Abstract
The present invention relates to an exhaust device for
internal-combustion-engine-driven small appliances. The exhaust
device includes a housing which has at least one exhaust inlet
opening and at least one exhaust outlet opening, and a flame
resonator for suppressing flames emerging from the exhaust device.
The flame resonator is arranged inside the housing and is
configured as a channel-like resonator cavity into which the
exhaust gas flows at least partly, whereby flames emerging from the
housing can be avoided in the exhaust gas.
Inventors: |
Kellermann; Christian;
(Stapelfeld, DE) ; Schweinberger; Henning;
(Hamburg, DE) |
Correspondence
Address: |
KELLY LOWRY & KELLEY, LLP
6320 CANOGA AVENUE, SUITE 1650
WOODLAND HILLS
CA
91367
US
|
Assignee: |
DOLMAR GMBH
Hamburg
DE
|
Family ID: |
38885343 |
Appl. No.: |
11/834270 |
Filed: |
August 6, 2007 |
Current U.S.
Class: |
60/299 ;
60/272 |
Current CPC
Class: |
F01N 2470/18 20130101;
F01N 13/1888 20130101; F01N 2230/06 20130101; F01N 2590/06
20130101; F01N 3/2885 20130101; F01N 13/002 20130101; F01N 1/084
20130101; F01N 13/1877 20130101 |
Class at
Publication: |
60/299 ;
60/272 |
International
Class: |
F01N 3/035 20060101
F01N003/035 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2006 |
DE |
20 2006 013 379.8 |
Claims
1. An exhaust device for internal-combustion-engine-driven small
appliances, comprising: a housing which has at least one exhaust
inlet opening, at least one exhaust outlet opening, and a flame
resonator for suppressing flames emerging from the exhaust device,
characterised in that the flame resonator is arranged inside the
housing and is configured as a channel-like resonator cavity into
which the exhaust gas flows at least partly, whereby flames
emerging from the housing can be avoided in the exhaust gas.
2. The exhaust device according to claim 1, characterised in that
the housing comprises at least one rear shell and a front shell,
which are brought together such that the insides of the shells lie
opposite to one another to form the housing.
3. The exhaust device according to claim 2, characterised in that
an intermediate shell is arranged between the rear shell and the
front shell.
4. The exhaust device according to claim 3, characterised in that a
first partial volume between the intermediate shell and the rear
shell forms the channel-like resonator cavity, having an an opening
in one direction only.
5. The exhaust device according to claim 4, characterised in that a
first partial volume between the intermediate shell and the front
shell forms the channel-like resonator cavity.
6. The exhaust device according to claim 5, characterised in that
the exhaust device comprises a catalyst which is arranged inside
the housing.
7. The exhaust device according to claim 6, characterised in that
the exhaust gas flows through the catalyst into the volume behind
the rear shell and the intermediate shell.
8. The exhaust device according to claim 7, characterised in that
after leaving the catalyst, the exhaust gas flows in a type of
bifurcation either into the first partial volume forming the
channel-like resonator cavity or into a second partial volume.
9. The exhaust device according to claim 8, characterised in that
the exhaust gas reaches the exhaust outlet opening through the
second partial volume.
10. The exhaust device according to claim 8, characterised in that
the exhaust device can be divided by a median line which runs
geometrically centrally over the housing, wherein the geometrical
configuration of the first partial volume and the second partial
volume is approximately symmetrical and extends on each side of the
median line.
11. The exhaust device according to claim 10, characterised in that
the catalyst is cylindrical and is arranged centrally on the median
line between the front shell and the intermediate shell or between
the rear shell and the intermediate shell.
12. The exhaust device according to claim 10, characterised in that
an insulating shell is provided between the rear shell and the
intermediate shell which runs approximately at the same distance
from a geometrical formation of the rear shell to form an
insulating gap.
13. The exhaust device according to claim 11, characterised in that
the insulating shell is arranged between the front shell and the
intermediate shell, and runs approximately at the same distance
from a geometrical formation of the front shell to form an
insulating gap.
14. The exhaust device according to claim 12, characterised in that
an insulating compound, in particular glass fibre insulation is
incorporated in the insulating gap.
15. The exhaust device according to claim 12, characterised in that
the rear shell, the insulating shell and the intermediate shell
have a respective opening which jointly form the exhaust inlet
opening.
16. The exhaust device according to claim 12, characterised in that
the intermediate shell comprises a cup-shaped inner contour with a
cup base and said cup base abuts in a plane-parallel manner against
the insulating shell.
17. The exhaust device according to claim 16, characterised in that
the separation of the first partial volume and the second partial
volume is formed by the cup-shaped inner contour of the
intermediate shell.
18. The exhaust device according to claim 13, characterised in that
a spacer sheet is arranged between the rear shell and the
insulating shell in the area of the exhaust inlet opening, wherein
the spacer sheet has a thickness according to the insulating
gap.
19. The exhaust device according to claim 17, characterised in that
a silencer element can be accommodated in the cup-shaped inner
contour.
20. A hand-held work machine, in particular chain saw, hedge
trimmer, rotary mower or the like, comprising an internal
combustion engine and an exhaust device (100) according to claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to an exhaust device, in
particular for small appliances operated by internal combustion
engines, comprising a housing which is formed at least from one
rear shell and one front shell. The housing comprises at least one
exhaust inlet opening and at least one exhaust outlet opening,
wherein a catalyst is optionally arranged inside the housing and
wherein the exhaust device further has a flame resonator for
suppressing flames emerging from the exhaust device.
PRIOR ART
[0002] Such exhaust devices are used in particular in hand-operated
small appliances with an internal combustion engine such as chain
saws, hedge trimmers, angle grinders, lawn trimmers and the
like.
[0003] Portable internal combustion engines for small appliances
are usually designed as two-stroke engines and must adhere to
increasingly stricter exhaust regulations in many countries
important for sales. One possibility of adhering to these exhaust
regulations is to use a catalyst. In this case, the catalyst is
advantageously integrated in the exhaust. A problem however is the
flame formation after the catalyst since emerging flames are
unacceptable because of a possible fire hazard.
[0004] Known as a solution is a sufficiently long channel behind
the catalyst. This gives the flame a sufficient residence time or
path length inside the silencer for extinguishing purposes.
However, this channel must be very long, however, to reliably avoid
flames which under certain operating conditions of the appliance
can be "blown" out from the channel. Thus, this channel is
difficult to accommodate or cannot be accommodated in an
advantageous manner in compact silencers.
[0005] Known from DE 20 2005 007 861 U1 is an exhaust system for an
internal combustion engine comprising a housing in which at least
one opening is provided for an exhaust inlet and a further opening
for an exhaust outlet. Furthermore, the exhaust system comprises a
catalyst for cleaning exhaust gases of the internal combustion
engine which is provided in the housing of the exhaust system in
such a manner that at least a substantial portion of the exhaust
gases flow through the catalyst. The design of the exhaust system
also includes a rear shell and a front shell, the catalyst being
located between the two shells. However, the exhaust system is not
provided with a flame resonator so that flames can escape from the
housing of the exhaust device.
[0006] A device for extinguishing flames has already been proposed,
which is located inside an exhaust system for an internal
combustion engine behind a catalyst, and comprises a housing having
a housing cross-sectional area and further comprising an incoming
pipe for the flame extinguisher which has a first cross-sectional
area through which the incoming exhaust gas is guided and
comprising an outgoing pipe from the flame extinguisher which has a
second cross-sectional area through which the outgoing exhaust gas
is guided. At the same time, an expanding transition is provided
from the first cross-sectional area to the housing cross-sectional
area and a contracting transition from the housing cross-sectional
area to the second cross-sectional area. In this variant, both the
ingoing and the outgoing pipe are configured in a longitudinal
axis.
[0007] In the known exhaust devices and in particular in the known
devices for flame extinguishing, the problem arises that it is not
possible to integrate a device for flame extinguishing inside an
exhaust device according to the prior art designs as a result of
the respective geometrical formations. Rather, the problem arises
that in the known devices for flame extinguishing a considerable
amount of space is required so that the ingoing and outgoing pipes
to the flame extinguisher must be guided around the housing of the
exhaust device which means considerable complexity of design and
production technology and takes up additional space which in turn
prevents or makes it difficult to achieve a compact and small
design of the complete exhaust device.
[0008] Conventional exhaust devices have an exhaust outlet opening
adjoining the device for flame extinguishing. However, the flame
extinguisher itself is a single component so that this gives rise
to the problem of executing the flame extinguisher jointly and
uniformly with the exhaust device.
[0009] Known from DE-PS 948 210 is a cyclone arrangement in a spark
extinguisher whereby glowing particles in the exhaust gas are
accelerated to the inside of the cyclone arrangement by the
centrifugal force. However, this design also comprises a device for
flame extinguishing having an elongated shape which is an
impediment for a compact design of an exhaust device.
[0010] Furthermore, DE-PS 1 031 581 discloses a flame arrestor for
an exhaust pipe of internal combustion engines where a complex
labyrinth system is used to achieve a good flame protection effect
and at the same time to minimise the flowing resistance.
[0011] In such flame protection devices, on the one hand the
geometric formation is a problem since these cannot be integrated
in a compact design inside a housing of an exhaust device. On the
other hand, individual devices are required for the flame arrestor
or the spark extinguisher which again requires a complex
construction.
DESCRIPTION OF THE INVENTION
Object, Solution, Advantages
[0012] It is thus the object of the present invention to provide an
exhaust device with a flame resonator which overcomes the
disadvantages of the aforesaid prior art and has a simple
construction and allows the flame resonator to be integrated in an
exhaust device.
[0013] This object is achieved starting from an exhaust device
according to the preamble of claim 1 in conjunction with its
characterising features. Advantageous further developments of the
invention are specified in the dependent claims.
[0014] The invention includes the teaching that the flame resonator
is arranged inside the housing and is configured as a channel-like
resonator cavity into which the exhaust gas flows at least partly,
whereby flames emerging from the housing can be avoided in the
exhaust gas. The invention starts from the idea that the device for
flame extinguishing configured as a flame resonator is formed by an
advantageous geometric configuration of the exhaust gas guidance
inside the housing of the exhaust device.
[0015] The housing advantageously comprises at least one rear shell
and a front shell, which are brought together such that the insides
of the shells lie opposite to one another to form the housing. At
the same time, an intermediate shell is arranged between the rear
shell and the front shell, wherein a first partial volume between
the intermediate shell and the rear shell forms the channel-like
resonator cavity and wherein this only has an opening in one
direction. Consequently, the exhaust gas must flow in and out again
through this opening in the resonator cavity.
[0016] As an alternative embodiment, it can be provided that the
first partial volume between the intermediate shell and the front
shell forms the channel-like resonator cavity. Furthermore, the
exhaust device can comprise a catalyst which is arranged inside the
housing, the catalyst being located either between the intermediate
shell and the rear shell or between the intermediate shell and the
front shell.
[0017] The first partial volume of the flame resonator differs from
a second partial volume in that the exhaust gas flows through the
catalyst into the volume between the rear shell and the
intermediate shell and only reaches the exhaust outlet opening
through the second volume. The exhaust gas initially passes through
the catalyst into the U-shaped volume, where the two legs of the
U-shaped volume form the first partial volume and the second
partial volume. The catalyst from which the exhaust gas flows into
the partial volume is located in the median line of the U-shaped
space. In this case, the exhaust gas outlet opening only extends
out from the second partial volume so that this is configured as
channel-shaped and the channel only has an opening in one direction
and is closed at the end. This first partial volume thus acts as a
storage device for the exhaust gas coming from the catalyst, where
the storage device can only be emptied via the channel of the
second partial volume. At the same time, the storage device can
built up a counter-pressure for a two-stroke engine. Accordingly,
the size of the first partial volume should be dependent on the
cylinder volume of the engine. Appropriately, the first partial
volume can hold a multiple integer of the cylinder volume.
[0018] According to a further advantageous embodiment of the
invention, it is provided that the exhaust device can be divided by
a median line which runs geometrically centrally over the housing.
The geometrical configuration of the first partial volume and the
second partial volume is approximately symmetrical and an equally
large first and second partial volume extends on each side of the
median. The rear shell, the front shell and the intermediate shell
can be produced as deep-drawn sheet-metal components so that the
intermediate shell forms a wall for separating the two partial
volumes from one another. The intermediate shell has a cup-shaped
contour where the cup base is configured such that it is
plane-parallel in the direction of the rear shell. However, the
cup-shaped recess of the inner contour does not extend over the
total width at the side of the median line so that the respective
first and second partial volumes are formed from the respective
side of the cup-shaped inner contour as far as the wall of the rear
shell.
[0019] According to a further advantageous exemplary embodiment of
the invention, the catalyst is cylindrical and is arranged
centrally on the median line between the front shell and the
intermediate shell. Alternatively, the catalyst can also be
arranged between the rear shell and the intermediate shell.
According to an additional exemplary embodiment, an insulating
shell is provided between the rear shell and the intermediate shell
which runs approximately at the same distance from the geometrical
formation of the rear shell to form an insulating gap. The
insulating gap is filled with an insulating compound for thermal
and sound-emitting purposes, where the insulating compound can
comprise a glass fibre insulation for example. Thus, the insulating
shell forms the inner side of the rear shell or that of the front
shell depending on whether the resonator cavity is formed between
the intermediate shell and the rear shell or between the
intermediate shell and the front shell.
[0020] Advantageously, the rear shell, the insulating shell and the
intermediate shell have a respective opening which jointly form the
exhaust inlet opening. Furthermore, the cup base of the
intermediate shell is configured as plane-parallel to the
insulating shell where the cup-shaped inner contour runs
approximately centrally over the median line and is therefore
arranged adjacent to the catalyst.
[0021] If the exhaust gas now enters through the exhaust inlet
opening, through the rear shell, the insulating shell and the
intermediate shell into the cup-shaped contour of the intermediate
shell, this initially flows through a silencer element accommodated
inside the cup-shaped inner contour of the intermediate shell. The
intermediate shell initially isolates the space between the
intermediate shell and the rear shell or the insulating shell which
forms the first partial volume or the second partial volume. The
exhaust gas thus flows into the space between the intermediate
shell and the front shell so that after the exhaust gas has flowed
through the silencer element, this is pressed into the catalyst.
The catalyst forms the only fluidic connection between the space
between the intermediate shell and the front shell and the space
between the intermediate shell and the insulating shell or the rear
shell.
[0022] The exhaust gas now flows backwards, in the opposite
direction to the exhaust gas flow through the exhaust inlet
opening, through the cylindrical catalyst into the first and second
partial volume. Since the first partial volume is configured as a
channel which is open on one side, possible flames which can be
formed after the catalyst flow into the first partial volume in
which they are smothered. The exhaust gas then flows in the
direction of the exhaust outlet opening through the second partial
volume where turbulence forms between the first partial volume and
the second partial volume which ultimately smothers the flames
formed after the catalyst. Flame formation can thus be reliably
suppressed so that the exhaust gas flows from the exhaust outlet
opening free from flames and sparks and leaves the exhaust
device.
[0023] According to a further advantageous exemplary embodiment of
the invention, it is provided that a spacer sheet is arranged
between the rear shell and the insulating shell in the area of the
exhaust inlet opening, wherein the spacer sheet has a thickness
according to the insulating gap. The spacer sheet forms a
stiffening of the region of the respective openings within the rear
shell, the front shell and the intermediate shell, the spacer sheet
also comprising an opening so that this borders the openings in the
respective shells. Thus, a stiffening is achieved so that the
exhaust device can be screwed to the internal combustion engine in
the area of the openings. In this case, the thickness of the spacer
sheet corresponds to the thickness of the insulating gap so that
when the respective shells are screwed tightly, the insulating gap
and the insulating mass located therein are not pressed together.
Furthermore, the spacer sheet can also be used for holding the
exhaust device on the motor or cylinder.
[0024] The rear shell, the front shell, the intermediate shell and
the insulating can be executed as deep-drawn sheet-steel
components, where the steel sheet can comprise structural steel,
optionally with coating or surface quenching and tempering such as
galvanising, or as stainless steel.
[0025] The rear shell, the insulating shell and the intermediate
shell can be joined via a common dovetailed or caulked, pressed,
soldered or welded edge since the respective shells must not
usually be separated from one another in use. The front shell can
also be joined positively to the remaining shells and it can
further be provided that the front shell is likewise screwed to the
internal combustion machine with the screw connection of the
exhaust device and thus can be detachably arranged on the remaining
shells.
[0026] Furthermore, the present invention is also directed at a
hand-held work machine, in particular chain saw, hedge trimmer,
rotary mower or the like, comprising an internal combustion engine
and an exhaust device according to any one of the claims 1 to
19.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Further measures which improve the invention are specified
in the dependent claims or are presented in detail hereinafter
jointly with the description of a preferred exemplary embodiment of
the invention with reference to the figures. Shown purely
schematically in the figures:
[0028] FIG. 1 is an exploded view of the individual shells of an
exhaust device according to the present invention;
[0029] FIG. 2a is a cross-section of the exhaust device according
to the present invention in mounted form;
[0030] FIG. 2b is a plan view of the exhaust device from FIG.
2a;
[0031] FIG. 2c is a cross-sectional side view of the exhaust device
from FIG. 2a or FIG. 2b;
[0032] FIG. 2b is a plan view of the exhaust device, where the
front shell is removed; and
[0033] FIGS. 3a,b are each perspective views of the exhaust device,
where the front shell is removed in each case.
BEST MODE FOR CARRYING OUT THE INVENTION
[0034] The exemplary embodiment shown in FIGS. 1 to 3b shows an
exhaust device 100 which has a channel-shaped resonator cavity
formed between the intermediate shell 15 and the rear shell 10.
However, it is expressly noted that the configuration of the
channel-shaped resonator cavity can also be formed between the
intermediate shell and the front shell.
[0035] FIG. 1 shows the exhaust device 100 according to the
invention in an exploded view, where four shells, namely the rear
shell 10, insulating shell 19, the intermediate shell 15 and the
front shell 11 are shown successively from left to right in their
respective joining positions in front of one another. The
respective shells are configured as cup-shaped deep-drawn
components and each comprise a steel sheet. The rear shell 10 and
the front shell 11 form the outer contour of the exhaust device 100
and have a respective inner volume which jointly form the volume of
the housing when the rear shell 10 and the front shell 11 are
brought together.
[0036] Located between the rear shell 10 and the front shell 11 are
the intermediate shell 15 and the insulating shell 19. The
insulating shell 19 has approximately the same contour as the rear
shell 10 so that both shells can be brought together with their
respective walls plane-parallel to one another. An insulating gap
is formed between the two shells 10, 19 which can be filled with an
insulating compound.
[0037] The intermediate shell 15 is not configured as entirely
shell-shaped but merely has a cup-shaped inner contour with a cup
base 21 where the cup base 21 abuts plane-parallel against the
insulating shell 19 in the joined state. The rear shell 10, the
insulating shell 19 and the intermediate shell 15 show a respective
opening 20, where the rear shell 10 embraces the opening 20a, the
insulating shell 19 embraces the opening 20b and the intermediate
shell 15 embraces the opening 20c. If the three shells 10, 15 and
19 are brought together, the openings 20a, 20b, 20c form the
exhaust inlet opening 12. Adjacent to the exhaust inlet opening 12
are round hole-like openings through which connecting elements such
as, for example, screws etc. can be passed. Furthermore, the front
shell 11 likewise has two openings so that this can likewise be
placed and fastened on the three remaining shells 10, 15 and 19 by
means of the same screw connection.
[0038] The intermediate shell 15 comprises a catalyst 14 through
which the exhaust gas can be passed completely. It is also feasible
to additionally provide bypass holes so that the exhaust gas is not
passed completely through the catalyst 14 but that a partial stream
of the exhaust gas bypasses the catalyst. Provided between the rear
shell 10 and the insulating shell 19 is a spacer sheet 22 which
likewise comprises an opening 20, as well as the openings for
passing through screw elements arranged next to the opening. The
spacer sheet 22 has a thickness which corresponds to the thickness
of the insulating gap so that this is maintained when the shells
10, 15 and 19 are tightly screwed.
[0039] In addition, the spacer sheet 22 provides an increase in
strength or an improvement in the force application of the exhaust
device 100 in the direction of the internal combustion engine which
accommodates this. The exhaust gas leaves the exhaust device 100
through an exhaust outlet opening 13 which is provided both in the
rear shell 10 and also in the insulating shell 19. If the
insulating shell 19 is joined equidistantly to the rear shell 10,
the respective exhaust outlet opening 13 forms a common exhaust
channel.
[0040] If the insulating shell 19 shown in the figures, which need
not necessarily be provided, is used in the exhaust device 100
according to the invention, additional ventilation openings can be
provided, for example, in the rear shell 10 through which fresh air
passes for cooling the exhaust device 100. The fresh air cools the
insulating shell 19 from its back side facing the rear shell 10.
Optionally, any available engine cooling area can be used for
cooling the rear shell 10 in which this is guided, for example, at
least through the ventilation openings in the rear shell 10. The
exhaust outlet opening 13 can likewise be provided with a venturi
nozzle whereby fresh ambient air is sucked into the exhaust device
100 to bring about early mixing of the fresh air with the hot
exhaust gases.
[0041] FIGS. 2a, 2b, 2c and 2d show the exhaust device 100, where
the front shell 11 has been removed in the diagram in FIG. 2d in
order to show the exhaust device 100 in plan view and to illustrate
the geometrical formation of the intermediate shell 15. FIG. 2a
shows the exhaust device 100 in a cross-section so that the rear
shell 10, the front shell 11, the exhaust inlet opening 12, the
exhaust outlet opening 13, the intermediate shell 15 and the
openings 20a, 20b, 20c can be identified. Shown between the
intermediate shell 15 and the insulating shell 19 or the rear shell
10 on the left side of the plane of the diagram is the first
partial volume 16 which forms the resonator cavity or storage
device for the flame resonator. The second partial volume 17 which
leads in the direction of the exhaust outlet opening 13, can be
seen on the opposite side on the right in the plane of the diagram.
The respective first and second partial volumes 16, 17 are formed
by the special geometric configuration of the intermediate shell
15, where the boundary of the partial volumes 16, 17 is formed in
particular by the cup-shaped inner contour of the intermediate
shell 15. Also, it can be clearly seen that the intermediate shell
15 adjoins the insulating shell 19 in the area of the cup base
21.
[0042] FIG. 2b merely shows a plan view of the exhaust device 100
where the median line 18 as shown in FIG. 2a runs centrally through
the exhaust device 100 and divides this into a left and a right
partial region which are each formed approximately symmetrical with
respect to one another. Merely the right partial region comprises
the exhaust outlet opening 13.
[0043] FIG. 2c shows the exhaust device 100 in another
cross-sectional plane which lies in the plane of the median line 18
according to FIGS. 2a and 2b as well as 2d. Thus, the catalyst 14
can be seen as well as the gap between the rear shell 10 and the
insulating shell 19. It is clear that the exhaust gas entering
through the exhaust inlet opening 12 passes directly into the
cup-shaped recess of the intermediate shell 15 and only passes
through the catalyst 14 before then entering into the space between
the intermediate shell 15 and the insulating shell 19. Moreover,
the openings 20a, 20b, 20c which jointly form the exhaust inlet
opening 12 can also be seen from FIG. 2c.
[0044] It is clear in FIG. 2d that the first partial volume 16 is
located on the left of the median line 16, the second partial
volume 17 being provided on the right. If the exhaust gas now flows
through the catalyst 14 into the U-shaped space below the
intermediate shell 15, this can either flow directly in the
direction of the second partial volume 17 and leave the exhaust
device 100 through the exhaust outlet opening 13 whereas when the
exhaust gas flows from the catalyst 14 in the direction of the
first partial volume 16, the exhaust gas flows into the closed
region. Possible flame formations are thereby reduced or made
turbulent in such a manner that these cannot escape from the
exhaust outlet opening 13.
[0045] It can furthermore be identified that all the radii offer
production technology advantages so that the respective shells 10,
11, 15 and 19 can be configured as deep-drawn parts. The shells can
either be joined positively holding to their respective edges or by
a screw connection to the holes provided close to the exhaust inlet
opening 12.
[0046] FIGS. 3a and 3b again show a diagram of the exhaust device
100 where this is in perspective view without showing the front
shell 11. Thus, the inner side of the exhaust device 100 can be
seen where the upper terminating shell forms the intermediate shell
15. The catalyst 14 is preferably detachably affixed to the
intermediate shell 15 where in particular, the cup-shaped recess in
the intermediate shell 15 can be identified in FIGS. 3a and 3b. The
exhaust inlet opening 12 formed by the openings 20a, 20b and 20c
can also be identified. As a result of its depth, the cup base 21
directly adjoins the insulating shell 19, a gap being formed
between the cup base 21 and the insulating shell 19 as well as the
rear shell 10, as can be seen in FIG. 3a and FIG. 3b.
[0047] The present invention is not restricted in its
implementation to the previously specified preferred exemplary
embodiment. Rather, a number of variants are feasible which also
make use of the solution shown in fundamentally different types of
designs.
REFERENCE LIST
[0048] 100 Exhaust device [0049] 10 Rear shell [0050] 11 Front
shell [0051] 12 Exhaust inlet opening [0052] 13 Exhaust outlet
opening [0053] 14 Catalyst [0054] 15 Intermediate shell [0055] 16
First partial volume [0056] 17 Second partial volume [0057] 18
Median line [0058] 19 Insulating shell [0059] 20 Opening [0060] 21
Cup base [0061] 22 Spacer sheet
* * * * *