DE202006013379U1 - Exhaust device with a flame resonator - Google Patents

Abstract

exhaust device (100), in particular for internal combustion engine operated small appliances, with a housing, which at least one exhaust gas inlet opening (12) and at least one exhaust gas outlet opening (13), and wherein the exhaust device further comprises a flame resonator for suppressing comprising flames emanating from the exhaust device, characterized that the flame resonator disposed within the housing and as a channel-like resonator space is formed, in which the exhaust gas at least partially flows in, resulting from the housing Escaping flames in the exhaust are avoidable.

Description

The The present invention relates to an exhaust device, in particular for internal combustion engine driven Small appliances, with a housing, which at least from a rear shell and a front shell is formed. The housing has at least one exhaust gas inlet opening and at least one Exhaust gas outlet opening optionally with a catalyst disposed within the housing and wherein the exhaust device further comprises a flame resonator for suppression includes flames emanating from the exhaust device.

such Exhaust systems are particularly applicable to manual small appliances with an internal combustion engine such as chainsaws, hedge trimmers, cut-off grinders, Grass trimmers and the like.

portable Internal combustion engines for small appliances are mostly as two-stroke engine devices executed and have to in many important countries comply with increasingly stringent emission regulations. A possibility, To comply with these emission regulations is the use of a catalyst. The catalyst is advantageously integrated in the exhaust device. However, the problem is a flame formation after the catalyst, because escaping flames because of a possible fire danger unacceptable are.

When solution For example, a sufficiently long channel is known behind the catalyst. As a result, the flame for the purpose of extinction a sufficient residence time or path length inside the muffler given. However, this channel must be for reliable avoidance of flames that under certain operating conditions of the device the channel can be "blown" very long running be. Therefore, this channel is heavy in compact silencers or not to be accommodated in an advantageous manner.

From the DE 20 2005 007 861 U1 an exhaust system for an internal combustion engine with a housing is known in which at least one opening for an exhaust gas inlet and a further opening for an exhaust gas outlet is provided. Furthermore, the exhaust system comprises a catalyst, which is arranged for purifying exhaust gases of the internal combustion engine in the housing of the exhaust system such that at least a substantial part of the exhaust gases flows through the catalyst. The design of the exhaust system also includes a rear shell and a front shell, wherein the catalyst is disposed between the two shells. However, the exhaust system is not designed with a flame resonator, so that the flames can escape from the housing of the exhaust device.

It a device for flame extinguishing has already been proposed, which behind within an exhaust system for an internal combustion engine a catalyst is arranged, and has a housing with a housing cross-sectional area, and further with an incoming tube to the flame extinguisher, which a first cross-sectional area and through which the incoming exhaust gas is passed, and with an outgoing Tube from the flame extinguisher, which has a second cross-sectional area and through the discharged the exiting exhaust gas becomes. This is an expanding transition from the first cross-sectional area to Housing cross-sectional area and a decreasing transition from the housing cross-sectional area to second cross-sectional area available. In this variant, both the incoming and the the lead out Tube in a longitudinal axis educated.

at the known exhaust devices and in particular in the known Devices for flame extinguishing arises the problem that the integration of a device for flame out within an exhaust device due to the respective geometric Training not according to the comments of the prior art possible is. Rather, the problem arises that in the known devices for flame extinguishing a considerable space is used, so that the incoming and leading out Pipes to the flame extinguisher consuming the case of the Exhaust system led around need to be what Significant design and manufacturing effort means and also takes up space, which in turn is a compact and physically small execution the entire exhaust system prevents or impedes.

ordinary Exhaust devices have an exhaust gas outlet opening, to which the Apparatus for flame extinguishing followed. However, the flame extinguisher represents itself a single component, so that's the problem gives, the flame extinguisher with the exhaust device together and perform uniformly.

From the DE-PS 948 210 For example, a cyclone arrangement is known in the case of a spark extinguisher, whereby flare particles in the exhaust gas are thrown to the inside of the cyclone arrangement by the generated centrifugal force. However, this embodiment also has a device for flame extinguishing with an elongated shape, which is a hindrance for a compact design of an exhaust device.

Further, the DE-PS 1 031 581 a flameout protection for an exhaust pipe of internal combustion engines, wherein a complex labyrinth system is used to obtain a good flame protection effect and at the same time to minimize flow through resistance.

at Such flame protection devices on the one hand, the geometric Training is a problem because these are not in a compact design within a housing integrate an exhaust device. On the other hand, respectively Individual devices for the flame arrester protection or the spark extinguisher required, which in turn requires a complicated construction.

It is therefore the object of the present invention, an exhaust device to provide with a flame resonator, which the disadvantages of the above The state of the art overcomes and has a simple construction and integration of the Flammenresonators allowed in an exhaust device.

These Task is based on an exhaust device according to the preamble of claim 1 in conjunction with its characterizing features solved. Advantageous developments of the invention are specified in the dependent claims.

The Invention includes the technical teaching that the flame resonator within the housing is arranged and formed as a channel-like resonator is, in which the exhaust gas at least partially flows, thereby emerging from the housing Flames in the exhaust gas is avoidable. The invention goes from the Thoughts that the designed as a flame resonator device for flame out by an advantageous geometric design of the exhaust system within of the housing the exhaust device is formed.

advantageously, includes the housing at least one rear shell and one front shell, which contribute to the formation of the housing shell inside opposite are brought together. It is located between the rear shell and the front shell an intermediate shell, wherein a first partial volume between the intermediate shell and the rear shell the channel-like Resonator space forms, and wherein this has an opening in one direction only. Consequently, the exhaust gas must pass through this opening into the resonator chamber in and out again.

When an alternative embodiment can be provided that the first part volume to form the channel-like Resonatorraumes between the intermediate shell and the Front shell is formed. Furthermore, the exhaust device can a Catalyst, which is disposed within the housing include, where the catalyst is either between the intermediate shell and the rear shell or between the intermediate shell and the front shell located.

The first partial volume of the flame resonator differs from one second partial volume characterized in that the exhaust gas through the catalyst in the volume flows in between the rear shell and the intermediate shell, and only passes through the second part volume to the exhaust outlet opening. The exhaust gas occurs first through the catalyst into the U-shaped Volume, wherein the two legs of the U-shaped volume, the first sub-volume and form the second subvolume. The catalyst from which the Exhaust gas flows into the sub-volumes, is in the bisector of the U-shaped Room arranged. In this case, the exhaust gas outlet extends only out of the second sub-volume, so that this channel-shaped is, and the channel has an opening in one direction only and closed at the end is. This first partial volume thus acts as a memory for that exhaust gas from the catalytic converter, the storage being only via the duct of the second sub-volume can be emptied. At the same time can through the store a back pressure for built a two-stroke engine. Accordingly, the size of the first Partial volume on the cylinder volume of the engine off. Conveniently, For example, the first subvolume may be a multiple whole of the cylinder volume hold.

According to one further advantageous embodiment the invention it is provided that the exhaust device through a geometric over the housing extending Seitenhalbierende is subdivided. The geometric Design of the first sub-volume and the second sub-volume is approximately symmetrical, and it extends to each side for side bisecting a roughly equal first and second sub-volume. The rear shell, the front shell and the intermediate shell are produced as deep-drawn sheet metal components, so that the intermediate shell represents a wall to the two sub-volumes from each other separate. The intermediate shell has a cup-shaped inner contour, wherein the Pot bottom formed plane-parallel in the direction of the rear shell is. The cup-shaped However, deepening of the inner contour does not extend beyond the entire width laterally to the bisector, so that from the respective side of the cup-shaped Inner contour to the wall of the rear shell, the respective first and second partial volume arises.

According to a further advantageous embodiment of the invention, the catalyst is cylindrical, and is arranged centrally between the front shell and the intermediate shell on the side bisector. Alternatively, the catalyst can also be arranged between the rear shell and the intermediate shell. According to an additional embodiment is between the Rear shell and the intermediate shell provided an insulating shell, which is approximately equidistant from the geometric configuration of the rear shell to form an insulating gap. The insulating gap is filled due to thermal and sound-emitting purposes with an insulating, wherein it may be, for example, a fiberglass insulation in the insulating. Thus, the insulating shell forms the inside of the rear shell or the front shell, depending on whether the resonator between the intermediate shell and the rear shell or between the intermediate shell and the front shell is formed.

advantageously, have the rear shell, the insulating shell and the intermediate shell a respective breakthrough, which together form the exhaust gas inlet opening. Furthermore, the pot bottom of the intermediate shell is formed plane-parallel to the insulating shell, the cup-shaped Inner contour approximately in the middle above the bisector runs and thus located adjacent to the catalyst.

kick now the exhaust gas through the exhaust gas inlet opening through the rear shell, the insulating shell and the intermediate shell in the cup-shaped inner contour of Intermediate shell, flows through it this first a silencer element, which within the cup-shaped Inner contour of the intermediate shell is added. The intermediate shell isolated first the space between the intermediate shell and the rear shell or the Insulating shell, which the first partial volume and the second partial volume forms. The exhaust gas flows therefore in the space between the intermediate shell and the front shell, so that after flowing through of the silencer element the exhaust gas is forced into the catalyst. The catalyst forms the only fluidic connection between the space between the Intermediate shell and the front shell as well as the space between the Intermediate shell and the insulating shell or the rear shell.

The Exhaust gas flows now in the backward direction against the direction of the exhaust gas flow through the exhaust gas inlet opening the cylindrical one Catalyst in the first and the second partial volume. Because the first Partial volume is designed as a channel open only on one side, are possible Flames, which can form after the catalyst, in the first partial volume into which they are suffocated. The exhaust gas then flows in the direction of the exhaust gas outlet opening through the second partial volume passing between the first subvolume and the second subvolume Create turbulences, which is a final suffocation of the formed Cause flames after the catalyst. Thus, a reliable suppression of Flame formation can be achieved, so that the exhaust flame and spark-free from the exhaust outlet passes and leaves the exhaust system.

According to one further advantageous embodiment The invention provides that between the rear shell and the insulating shell arranged a spacer plate in the region of the exhaust gas inlet opening is, wherein the spacer plate has a thickness according to the insulating gap. The spacer plate forms a stiffening of the area of the respective openings within the rear shell, the front shell and the intermediate shell, wherein the spacer plate also includes a breakthrough, so this the breakthroughs outlined in the respective bowls. Thus, a stiffener achieved, so that in the area of the openings to the exhaust device the internal combustion engine can be screwed. The fat the spacer plate corresponds to the thickness of the insulating gap, so that with a firm bolting of the respective shells the Insulating gap and the insulating material located therein is not compressed. Furthermore, the spacer plate can also be used to hold the exhaust device be used on the engine or cylinder.

The Back shell, the front shell, the intermediate shell and the insulating shell can be designed as deep-drawn sheet steel components, wherein the steel sheet a structural steel - if necessary with coating or surface finish like z. B. galvanizing - or a stainless steel may include. The connection of the back shell, the insulating shell and the intermediate shell can be crimped together or caulked, pressed, soldered or welded edge as usual In use, the respective shell can not be separated have to. The front shell can be positively connected to the other shells, wherein it can further be provided that the front shell with the Screwing the exhaust device to the internal combustion engine also screwed, and thus detachable to the other shells can be arranged.

Further the present invention is also applicable to a hand-held work machine, especially chainsaw, Hedge trimmer, rotary mower or the like directed to an internal combustion engine and a Exhaust device according to a of claims 1 until 19.

Further, the invention improving measures are in the subclaims stated below or together with the description a preferred embodiment of the Invention with reference to the figures shown. Show it:

1 an exploded view of the single NEN shells of an exhaust device according to the present invention;

2a a cross section of the exhaust device according to the present invention in an assembled form;

2 B a plan view of the exhaust device 2a ;

2c a cross-sectional side view of the exhaust device 2a respectively. 2 B ;

2d a plan view of the exhaust device, wherein the front shell is removed; and

3a , b is a respective perspective view of the exhaust device, wherein in each case the front shell is removed.

That in the 1 to 3b illustrated embodiment shows an exhaust device 100 , which has a channel-like resonator space between the intermediate shell 15 and the back shell 10 is trained. However, it should be expressly understood that the configuration of the channel-like resonant space can also be formed between the intermediate shell and the front shell.

1 shows the exhaust device according to the invention 100 in an exploded view, with four shells, namely the rear shell 10 , Insulating shell 19 , the intermediate shell 15 as well as the front shell 11 successively from left to right in their respective joining position are shown standing in front of each other. The respective shells are designed as cup-shaped deep-drawn components and each comprise a steel sheet. The back shell 10 as well as the front shell 11 form the outer contour of the exhaust device 100 , and have a respective internal volume, which together form the volume of the housing when the rear shell 10 and the front shell 11 are brought together.

Between the back shell 10 and the front shell 11 are the intermediate shell 15 as well as the insulating shell 19 arranged. The insulating shell 19 has approximately the same contour as the rear shell 10 , so that the two shells with their respective wall can be brought plane-parallel to each other. Between the two bowls 10 . 19 creates an insulating gap, which can be filled with an insulating compound.

The intermediate shell 15 is not a total shell-like, but has only a cup-shaped inner contour with a pot bottom 21 on, with the bottom of the pot 21 in the assembled state plane-parallel to the insulating shell 19 is applied. The back shell 10 , the insulating shell 19 as well as the intermediate shell 15 show a respective breakthrough 20 , with the back shell 10 the break through 20a , the insulating shell 19 the break through 20b and the intermediate shell 15 the break through 20c include. Are the three bowls 10 . 15 and 19 brought on each other, so form breakthroughs 20a . 20b . 20c the exhaust gas inlet opening 12 , Next to the exhaust gas inlet 12 are round, hole-like openings provided through which fasteners such as screws, etc. can be passed. Furthermore, the front shell 11 also two openings on, so that these by means of the same screw also on the other three shells 10 . 15 such as 19 can be placed and fastened.

The intermediate shell 15 includes a catalyst 14 through which the exhaust gas is passed completely. It is also conceivable to additionally provide bypass bores, so that the exhaust gas is not completely through the catalyst 14 is passed, but that a partial flow of the exhaust gas flows past the catalyst. Between the back shell 10 and the insulating shell 19 is a spacer 22 provided, which also a breakthrough 20 includes, as well as arranged next to the opening breakthroughs for the passage of screw elements. The spacer plate 22 has a thickness which corresponds to the thickness of the insulating gap, so that this even with a firm screwing of the shells 10 . 15 and 19 maintained on each other.

In addition, the spacer plate offers 22 an increase in the strength or an improvement in the introduction of force of the exhaust device 100 in the direction of the internal combustion engine by which this is recorded. The exhaust gas leaves the exhaust system 100 through an exhaust gas outlet opening 13 which is in both the back shell 10 as well as in the insulating shell 19 is provided. Is the insulating shell 19 equidistant with rear shell 10 joined, so form the respective exhaust gas outlet opening 13 a common exhaust duct.

If in the exhaust device according to the invention 100 the insulating shell shown in the figures 19 used - which does not necessarily have to be present - can, for example, in the rear shell 10 additional ventilation openings may be provided, whereby fresh air for cooling the exhaust device 100 arrives. This fresh air cools the insulating shell 19 from its back, the back shell 10 is facing. Optionally, an existing engine cooling air can also be used to cool the rear shell 10 be used in which this z. B. at least through the ventilation openings in the rear shell 10 to be led. Likewise, the exhaust gas outlet opening 13 provided with a Venturi nozzle be, whereby the fresh ambient air into the exhaust system 100 is sucked to cause premature mixing of the fresh air with the hot exhaust gases.

The 2a . 2 B . 2c such as 2d show the exhaust system 100 , in the representation of the 2d the front shell 11 taken to the exhaust device 100 to show in the plan view and the geometric design of the intermediate shell 15 to clarify. The 2a shows the exhaust device 100 in a cross section, leaving the back shell 10 , the front shell 11 , the exhaust gas inlet 12 , the exhaust outlet 13 , the intermediate shell 15 as well as the breakthroughs 20a . 20b . 20c are recognizable. Between the intermediate shell 15 and the insulating shell 19 or the rear shell 10 is on the left side of the image plane, the first sub-volume 16 represented, which forms the resonator chamber or memory for the flame resonator. On the opposite side right in the image plane is the second subvolume 17 recognizable, which in the direction of the exhaust gas outlet opening 13 leads. The respective first and second partial volumes 16 . 17 caused by the special geometric design of the intermediate shell 15 , where the limitation of subvolumes 16 . 17 in particular by the cup-shaped inner contour of the intermediate shell 15 arises. It can also be clearly seen that the intermediate shell 15 in the area of the pot bottom 21 to the insulating shell 19 borders.

2 B shows only a plan view of the exhaust device 100 , wherein the bisector 18 as well as in 2a shown centrally through the exhaust device 100 extends and these divided into a left and a right portion, which are each formed approximately symmetrical to each other. Only the right subregion comprises the exhaust gas outlet opening 13 ,

The 2c shows the exhaust device 100 in a further cross-sectional plane, which in the plane of the bisector 18 according to the 2a and 2 B such as 2d lies. This is the catalyst 14 recognizable, as well as the gap between the rear shell 10 as well as the insulating shell 19 , It becomes clear that this through the exhaust gas inlet 12 entering exhaust gas directly into the cup-shaped depression of the intermediate shell 15 and only through the catalyst 14 then pass into the space between the intermediate shell 15 and the insulating shell 19 to get. Fer ner are also the 2c the breakthroughs 20a . 20b . 20c recognizable, which together the exhaust gas inlet opening 12 form.

In the 2d it becomes clear that the first partial volume 16 on the left side of the bisector 18 is arranged, wherein the second subvolume 17 is provided on the right side. The exhaust now flows through the catalyst 14 in the U-shaped space below the intermediate shell 15 , this may either be directly in the direction of the second sub-volume 17 inflow and the exhaust device 100 through the exhaust gas outlet 13 leave, however, where, in a flow of exhaust gas from the catalyst 14 in the direction of the first partial volume 16 the exhaust gas enters the closed area. Possible flame formations are thereby reduced or swirled in such a way that they do not escape from the exhaust gas outlet opening 13 can escape.

Furthermore, it can be seen that all radii provide manufacturing advantages, so that the respective shells 10 . 11 . 15 and 19 can be formed as deep-drawn parts. The connection of the shells can either be held in a form-locking manner at their respective edges or by a screw connection to the boreholes close to the exhaust gas inlet opening 12 are provided.

In the 3a and 3b is again a representation of the exhaust device 100 shown, these in perspective form without the representation of the front shell 11 is present. Thus, the inside of the exhaust device 100 recognizable, wherein the upper final shell, the intermediate shell 15 forms. At the intermediate shell 15 is the catalyst 14 preferably releasably secured, wherein in the 3a and 3b in particular the cup-shaped depression in the intermediate shell 15 is recognizable. Furthermore, the exhaust gas inlet opening 12 recognizable, which through the breakthroughs 20a . 20b and 20c is formed. The bottom of the pot 21 Due to its depth, it borders directly on the insulating shell 19 on, being between the bottom of the pot 21 and the insulating shell 19 as well as the back shell 10 a gap is formed, as in the 3a and 3b recognizable.

The present invention limited in their execution not to the above given, preferred embodiment. Rather, a number of variants is conceivable, which of the illustrated solution also in principle different types Use.

100

exhaust device

10

backshell

11

front shell

12

Exhaust gas inlet opening

13

Exhaust gas outlet opening

14

catalyst

15

intermediate shell

16

first partial volume

17

second partial volume

18

Seitenhalbierende

19

insulation shell

20

breakthrough

21

pot base

22

Distanzblech

Claims (20)

Exhaust device ( 100 ), in particular for internal combustion engine-driven small appliances, with a housing which has at least one exhaust gas inlet opening ( 12 ) and at least one exhaust gas outlet opening ( 13 ), and wherein the exhaust device further comprises a flame resonator for suppressing flames emerging from the exhaust device, characterized in that the flame resonator is disposed within the housing and formed as a channel-like resonator chamber, in which the exhaust gas flows at least partially, whereby from the housing Escaping flames in the exhaust are avoidable. Exhaust device according to claim 1, characterized in that the housing at least one rear shell ( 10 ) and a front shell ( 11 ), which are brought to form the housing shell inside opposite to each other. Exhaust device according to claim 2, characterized in that between the rear shell ( 10 ) and the front shell ( 11 ) an intermediate shell ( 15 ) is arranged. Exhaust device according to claim 3, characterized in that a first partial volume ( 16 ) between the intermediate shell ( 15 ) and the Hinderschale ( 10 ) forms the channel-like resonator, which has an opening in one direction only. Exhaust device according to claim 3, characterized in that the first partial volume ( 16 ) between the intermediate shell ( 15 ) and the front shell ( 11 ) forms the channel-like resonator space. Exhaust device according to one of the preceding claims, characterized in that the exhaust device comprises a catalyst ( 14 ), which is disposed within the housing. Exhaust device according to one of the preceding claims, characterized in that the exhaust gas through the catalyst ( 14 ) in the volume between the rear shell ( 10 ) and the intermediate shell ( 15 ) flows in. Exhaust device according to claim 7, characterized in that the exhaust gas after leaving the catalyst ( 14 ) in the manner of a bifurcation either into the channel-like resonator chamber forming the first partial volume or into a second partial volume ( 17 ) flows in. Exhaust device according to claim 7, characterized in that the exhaust gas through the second partial volume ( 17 ) to the exhaust gas outlet opening ( 13 ). Exhaust device according to claim 8 or 9, characterized in that the exhaust device by a geometrically centrally extending over the housing side bisector ( 18 ) is subdividable, wherein the geometric configuration of the first sub-volume ( 16 ) and the second sub-volume ( 17 ) is approximately symmetrical, and one side each to the bisector ( 18 ). Exhaust device according to one of the preceding claims, characterized in that the catalyst ( 14 ) is cylindrical, and between the front shell ( 11 ) and the intermediate shell ( 15 ) or between the back shell ( 10 ) and the intermediate shell ( 15 ) centered on the bisector ( 18 ) is arranged. Exhaust device according to one of claims 3 to 11, characterized in that between the rear shell ( 10 ) and the intermediate shell ( 15 ) an insulating shell ( 19 ) is provided, which is approximately equidistant from the geometric configuration of the rear shell ( 10 ) extends to form an insulating gap. Exhaust device according to one of claims 3 to 11, characterized in that the insulating shell ( 19 ) between the front shell ( 11 ) and the intermediate shell ( 15 ) is arranged, and approximately equally spaced from the geometric design of the front shell ( 11 ) extends to form an insulating gap. Exhaust device according to claim 12 or 13, characterized in that in the insulating gap an insulating compound, in particular a fiberglass insulation is introduced. Exhaust device according to one of the preceding claims, characterized in that the rear shell ( 10 ), the insulating shell ( 19 ) and the intermediate shell ( 15 ) a respective breakthrough ( 20a . 20b . 20c ), which together the exhaust gas inlet opening ( 12 ) form. Exhaust device according to one of the preceding claims, characterized in that the intermediate shell ( 15 ) a cup-shaped inner contour with a pot bottom ( 21 ), and the pot ground ( 21 ) plane-parallel to the insulating shell ( 19 ) is present. Exhaust device according to one of the preceding claims, characterized in that the separation of the first partial volume ( 16 ) and the second sub-volume ( 17 ) through the cup-shaped inner contour of the intermediate shell ( 15 ) is formed. Exhaust device according to one of the preceding claims, characterized in that between the rear shell ( 10 ) and the insulating shell ( 19 ) a spacer plate ( 22 ) in the region of the exhaust gas inlet opening ( 12 ) is arranged, wherein the spacer plate ( 22 ) has a thickness according to the insulating gap. Exhaust device according to one of claims 16 to 18, characterized in that in the cup-shaped inner contour of a silencer element is receivable. Hand-held work machine, in particular chain saw, hedge trimmer, rotary mower or the like, with an internal combustion engine and an exhaust device ( 100 ) according to any one of the preceding claims.