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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

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:

FIG. 1 is an exploded view of the individual shells of an exhaust device according to the present invention;

FIG. 2 a is a cross-section of the exhaust device according to the present invention in mounted form;

FIG. 2 b is a plan view of the exhaust device from FIG. 2a;

FIG. 2 c is a cross-sectional side view of the exhaust device from FIG. 2a or FIG. 2b;

FIG. 2 b is a plan view of the exhaust device, where the front shell is removed; and

FIGS. 3 a,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

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.

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.

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.

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.

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.

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.

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.

FIGS. 2 a, 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.

FIG. 2 b 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.

FIG. 2 c 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.

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.

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.

FIGS. 3 a 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.

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

• 100 Exhaust device
• 10 Rear shell
• 11 Front shell
• 12 Exhaust inlet opening
• 13 Exhaust outlet opening
• 14 Catalyst
• 15 Intermediate shell
• 16 First partial volume
• 17 Second partial volume
• 18 Median line
• 19 Insulating shell
• 20 Opening
• 21 Cup base
• 22 Spacer sheet

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.