EP1639237A1

EP1639237A1 - Particulate filter, in particular for internal combustion engine exhaust gases

Info

Publication number: EP1639237A1
Application number: EP04738485A
Authority: EP
Inventors: Helmut Knoedl; Klaus Mueller
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2003-06-24
Filing date: 2004-05-07
Publication date: 2006-03-29
Also published as: KR20060069359A; DE10328188A1; BRPI0411722A; WO2005010326A1; JP2006526105A; US20070089384A1; CN1813119A

Abstract

The invention concerns a particulate filter (11), in particular for internal combustion engine exhaust gases. Said particulate filter (11) comprises a housing (12) and a filtering body (13) housed therein. Said filtering body (13) has several filter walls (15) extending from a longitudinal axis (14) of the particulate filter (11), substantially radially towards the longitudinal axis (14) and located spaced apart from one another in the peripheral direction. The filter walls (15) are bonded, at their surface, at least partly to at least one fixing element (16) whereby the filtering body (13) is fixed in the housing (12). The invention aims at maximum limitation of the transmission movements of the fixing element (16) to the housing (12). Therefor, the fixing element (16) has compensation means, acting between the filter walls (15) and the housing (12), which compensate the relative movements between the filter walls (15) and the housing (12). Thus, it is possible to compensate the movements resulting from heat of the filter walls (15) and avoid the presence of stresses at the fixing element (16).

Description

Particulate filters, in particular for exhaust gases from internal combustion engines

The present invention relates to a particle filter, in particular for exhaust gases from internal combustion engines. The particle filter comprises a housing and a filter body arranged therein. The filter body has a plurality of filter walls which, starting from a longitudinal axis of the particle filter, extend essentially in the radial direction and in the direction of the longitudinal axis. The filter walls are spaced apart in the circumferential direction. The filter walls are at least partially welded or soldered to their end faces with at least one fastening element, via which the filter body is fastened in the housing.

State of the art

Particulate filters are used in particular in connection with diesel internal combustion engines in order to reduce unwanted soot emissions as soot filters. Particle filters of the type mentioned at the outset are, for example, from DE 101

28 938 AI known, to which reference is expressly made with regard to the structure and functioning of a particle filter. The use of particle filters has not yet become widespread, as it is used in the Practice are not without problems, especially with regard to their storage capacity.

For some time now, particle filters with an increased storage capacity have been tested, the filter bodies with

Have filter walls made of a sintered metal. Metallic fibers or grains are sintered together with a metallic carrier mat to form filter plates. Various filter designs can be displayed from the plates. In particular, the filter plates as

Filter walls are used for the filter body. The soot particles are separated on their surface as they flow through the filter walls.

In a particular type of sintered metal filter, the filter body comprises a plurality of filter walls which, starting from the longitudinal axis of the particle filter, extend essentially in the radial direction and in the direction of the longitudinal axis and which are spaced apart from one another in the circumferential direction. Two adjacent filter walls each form a so-called filter bag. The filter body is fastened to a fastening element, which in turn is fastened to the housing of the particle filter, so that the filter body is positioned in the housing via the fastening element and fastened therein. The filter walls are at least partially welded or soldered to the fastening element at least on one of their end faces arranged in the axial direction.

From time to time, the particles that have accumulated in the particle filter must be removed from the particle filter. The particles are usually burned off at relatively high temperatures from around 550 ° C. This process is also called regeneration of the particle filter. During regeneration, the filter bags heat up more than the fastening element. Since that

Fastener is attached to the housing, arise from the temperature differences and the resulting thermal expansion of the filter walls relative to that

Fastener Tensions in the welds or soldered connections with which the filter walls are fastened to the fastener, wherein the tensions can even lead to a breakage of the welds or soldered connections.

The present invention has for its object to design and develop a particle filter of the type mentioned in such a way that there are no tensions in the filter during the regeneration of the filter and no damage or even destruction of the weld seams or soldered connections between the filter walls and the fastener comes.

To solve this problem is based on the

Particulate filter of the type mentioned initially proposed that the fastening element between the fastening element and the housing has compensating means which compensate for relative movements of the filter walls relative to the housing.

Advantages of the invention

In the particle filter according to the invention, the filter pockets or the filter walls and the fastening element to which they are fastened can expand almost unhindered. This is particularly important in the regeneration of the particle filter, as this leads to temperature differences within the filter and due to the high temperatures can lead to a strong thermal expansion of the filter bags and the fastening element. According to the invention, the regions of the fastening element 5 connected to the filter pockets and the regions of the fastening element fastened to the housing of the particle filter are decoupled by the compensating means. As a result, the regions of the fastening element which are connected to the filter pockets are not prevented from engaging with the, if necessary

Extend L0 filter bags. As a result, the weld seams can expand almost unhindered in the radial direction and there are no tensions in the weld seams or soldered connections between the filter walls and the fastening element. With that

L5 prevents voltage breaks. According to the invention, the filter bags are therefore not welded directly to the part of the fastening element which is fastened to the housing, but indirectly via the compensating means.

_0 The particle filter can have only one fastening element or a plurality of fastening elements, for example a separate fastening element for each filter bag. The compensating means can be arranged between the housing and the fastening means.

According to an advantageous development of the present invention, however, it is proposed that the compensating means are an integral part of the at least one fastening element. The compensation means

30 can be designed as a separate component from the fastening element, which is integrated into the fastening element. However, it is also conceivable for the compensating means to be formed in one piece with the fastening element. 5 According to a preferred embodiment of the present invention, it is proposed that the fastening element has a radially outward-facing outer flange, on which the regions of the fastening element welded to the filter walls are located on their from the longitudinal axis of the

Particle filter facing away are attached and which is attached to the housing, wherein the compensating means between the outer flange and the areas of the fastener welded to the filter walls are arranged.

According to a further preferred embodiment of the invention, it is proposed that the fastening element has a radially outwardly directed outer flange, to which the regions of the fastening element welded to the filter walls are fastened on their side facing away from the longitudinal axis of the particle filter and which is fastened to the housing, the compensating means being arranged between a first region of the outer flange fastened to the housing of the particle filter and a second region of the outer flange fastened to the regions of the fastening element welded to the filter walls.

According to yet another preferred embodiment of the present invention, it is proposed that the fastening element has a radially inwardly directed inner flange, to which the regions of the fastening element welded to the filter walls are fastened on their side facing the longitudinal axis of the particle filter, the compensating means between those with the filter walls welded areas of the fastener and the inner flange are arranged. In the case of a particle filter with a cylindrical filter body, the longitudinal axis of the Particle filter through the inner flange and run the areas of the welded to the filter walls

Fastening element on the inner flange together or these areas of the fastening element are fastened to the inner flange in the direction of the longitudinal axis.

According to another advantageous development of the present invention, it is proposed that the fastening element have a material web folded at least once in the area of the compensating means. in the

In the area of the compensating means, a material web is therefore provided with a plurality of mutually spaced-apart web sections. This multi-layer material web in the area of the compensating means enables in particular a radial expansion of the weld seams between the

Filter walls and the fastener. In addition, the hot filter bags are isolated from the outside by the multi-layer material web, which results in a better and, above all, more effective regeneration of the particle filter and a cooler temperature of the housing from the outside. Furthermore, the filter bags can be attached to the housing via the multi-layer material web of the compensating means in such a way that mechanical vibrations or shock loads occurring during operation are cushioned and the weld seams are no longer so prone to breakage even due to mechanical loads.

The material web advantageously has a surface extension essentially transversely to the movement of the fastening element to be compensated for. It is advantageous if the surface extension of the material webs runs essentially parallel to the longitudinal axis of the particle filter and in each case with a substantially constant distance from the longitudinal axis. The material web is preferably folded once or three times. According to another preferred embodiment of the present invention, it is proposed that support means are arranged in an intermediate area between the folded web sections of the material web, which preferably comprise a corrugated support plate. It is also proposed that insulating means, which preferably comprise rock wool, be arranged in an intermediate region between the folded web sections of the material web.

Finally, it is proposed that, at least in regions, at least one inwardly curved bead is formed on a radially inner folded web section of the material web. The beads preferably run around the entire circumference of the inner web section of the material web, so that the filter pockets of the filter body can be supported in a radially inward direction.

Finally, it is proposed that the filter walls comprise a sintered material. Filter walls made of a sintered material can be fastened, preferably welded or soldered, to the fastening element on their axial end faces.

drawings

Further features, possible applications and advantages of the invention result from the following description of exemplary embodiments of the invention, which are shown in the drawing. All of the described or illustrated features, alone or in any combination, form the subject matter of the invention, regardless of their summary in the claims or their claims Relationship and regardless of their wording or representation in the description or in the drawing. Show it:

Figure 1 shows a particle filter according to the invention according to a first preferred embodiment in a perspective view in section;

Figure 2 shows a particle filter known from the prior art in a perspective view;

FIG. 3 shows a fastening element of the particle filter according to the invention in a detail according to a second preferred embodiment;

Figure 4 shows a fastening element of the particle filter according to the invention according to the first preferred embodiment of Figure 1 in a detail;

FIG. 5 shows a fastening element of the particle filter according to the invention in a detail according to a third preferred embodiment;

FIG. 6 shows a fastening element of the particle filter according to the invention in a detail according to a fourth preferred embodiment;

FIG. 7 shows a fastening element of the particle filter according to the invention in a detail according to a fifth preferred embodiment;

FIG. 8 shows a fastening element of the particle filter according to the invention in a detail according to a sixth preferred embodiment; FIG. 9 shows a fastening element of the particle filter according to the invention in a detail according to a seventh preferred embodiment;

FIG. 10 shows a fastening element of the particle filter according to the invention in a detail according to an eighth preferred embodiment;

FIG. 11 shows a fastening element of the particle filter according to the invention in a detail according to a ninth preferred embodiment;

FIG. 12 shows a fastening element of the particle filter according to the invention in a cutout in accordance with a tenth preferred embodiment;

Figure 13 shows a fastening element of the particle filter according to the invention according to an eleventh preferred embodiment in the cutout.

Description of the embodiments

FIG. 2 shows one known from the prior art

Particulate filter designated in its entirety with the reference number 1. Particulate filters are used in particular in connection with diesel internal combustion engines in order to reduce unwanted soot emissions as soot filters. The particle filter 1 comprises a housing 2 and a filter body 3 arranged therein when the particle filter 1 is ready for operation. FIG. 2 shows the filter body 3 outside the housing 2. A longitudinal axis of the particle filter 1 is designated by the reference number 4. The filter body 3 comprises several Filter walls 5, which, starting from the longitudinal axis 4 of the particle filter 1, extend essentially in the radial direction and in the direction of the longitudinal axis 4. The filter walls 5 are spaced apart from one another in the circumferential direction. Two adjacent filter walls 5 can form a so-called filter bag. The filter walls 5 are fastened, at least in regions, to a fastening element 6, in particular welded or soldered, on their end face directed upward in the axial direction.

The fastening element 6 comprises a radially outwardly directed outer flange 6a and a radially inwardly directed inner flange βb. Areas βc of the fastening element 6, which are welded to the end faces of the filter walls 5, extend in the radial direction between the outer flange βa and the inner flange βb. The outer flange 6a, the areas βc and the inner flange βb are rigidly connected to one another and in particular consist of one part. When the filter body 3 is inserted into the housing 2, the outer flange 6a comes to rest with a correspondingly designed region 2a of the housing 2. Openings βd and 2b are formed in the outer flange βa and in the region 2a of the housing 2, through which openings suitable fastening means, for example screws, can be passed in order to position the filter body 3 in the housing 2 and to fasten it in the desired position. Instead of the fastening means guided through the openings βd and 2b, the outer flange 6a can also be fastened in another way to the region 2a of the housing 2, for example by means of a welded connection.

The filter walls 5 comprise a sintered metal. To produce the filter walls 5, metallic fibers or grains are used with a metallic carrier mat sintered together. When exhaust gas from a diesel internal combustion engine flows through the particle filter 1, soot particles are deposited on the surface of the filter plates 5. From time to time, the particulate filter must be freed from the soot particles in a so-called regeneration phase. For this purpose, the particle filter 1 is heated to a very high temperature in the range of over 550 ° C. so that the soot particles burn as residue-free as possible. During the regeneration, the filter walls 5 heat up more than the outer flange βa and the inner flange βb. Since the outer flange 6a is fastened to the housing 2, the strong thermal expansion of the filter walls 5 and the regions 6c of the fastening element 6 connected to the end faces of the filter walls 5 lead to strong stresses in the weld seams between the filter seams 5 and the regions 6c of the Fastener 6 can lead.

The particle filter 11 according to the invention, as shown for example in FIG. 1, can remedy this. In the particle filter 11 according to the invention, the individual components were designated by the reference numerals from FIG. 2, but were increased by ten in each case. The particle filter 11 according to the invention in FIG. 1 is only shown in detail. For the sake of clarity, the filter walls 15 in particular are not shown. However, the fastening element 16, which is designed in a special way, can be clearly seen, with the outer flange 16a, the inner flange 16b and the regions 16c which are welded to the end faces of the filter walls 15. In the fastening element 16 of the particle filter 11 according to the invention, compensating means 17 are integrated, through which a movement of the areas lβc of the fastening element 16 welded to the filter walls 15, for example due to Temperature changes that can be compensated. Since, in the particle filter 11 according to the invention, the areas 16c of the fastening element 16 can be moved freely with the filter walls 15, tensions and resulting stress fractures of the weld seams can be effectively prevented.

In the embodiment shown in Figure 1, the compensating means 17 and the fastener 16 are formed as one part. However, it is also conceivable that the compensating means 17 and the fastening element 16 are designed as separate components. It is also possible that the particle filter 11 not only has a single fastening element 16, but also a plurality of fastening elements, for example one for each filter pocket.

The compensating means 17 in particular enable the regions 16c of the fastening element 16 to move in the radial direction. In the area of the compensating means 17, the fastening element 16 has a once folded material web, which has a surface extension essentially transverse to the movement of the fastening element 16 to be compensated for, namely parallel to the longitudinal axis 14 of the particle filter. In other words, the fastening element 16 of the particle filter 11 according to the invention in the embodiment shown in FIG. 1 is designed as a double-walled cylinder shell.

According to an exemplary embodiment shown in FIG. 7, support means 19, for example in the form of a wave-shaped support plate, can be arranged in an intermediate region 18 between the web sections 17a and 17b of the material web of the compensating means 17. The Support means 19 function, for example, as a spring element or as an insulation element.

According to an embodiment shown in Figure 8 in the intermediate area 18 between the

Path sections 17a and 17b of the material web of the compensating means 17, insulating means 20, for example in the form of rock wool, may be arranged. The insulation agent

20 are used for heat insulation of the filter body 13 to the outside, in particular during the regeneration of the

Particulate filter 11. This enables the regeneration to be made more efficient and the outside temperature of the housing 12 can be reduced.

Another advantage of the flexible connection of the

Filter walls 15 on the outer flange 16a is that vibrations or shock loads occurring during the operation of the internal combustion engine can be effectively cushioned and the weld seams between the filter walls 15 and the areas 16c of the fastening element 16 are no longer as likely to break even as a result of mechanical loads.

In the exemplary embodiment of the particle filter 11 shown in FIG. 9, the compensating means 17 is formed on the radially inside folded web section 17a of the material web of the compensating means 17 in the circumferential direction, at least in regions, at least inwardly curved bead 21. Through the bead 21, the filter walls 15 formed by side by side can be formed

Filter bags are supported. Instead of just one, several beads running in the circumferential direction can also be used

21 can be provided on the radially inner folded web section 17a of the material web of the compensating means 17 (see FIG. 10). According to a further exemplary embodiment of the particle filter 11 according to the invention shown in FIG. 11, on the radially inner folded web section 17a of the material web the compensating means 17 are formed in the longitudinal direction, parallel to the longitudinal axis 14 of the particle filter 11, inwardly curved beads 22. The beads 22 can improve the stability of the filter pockets formed by the filter walls 15.

In a further exemplary embodiment of the particle filter according to the invention shown in FIG. 12, the outer flange is divided into two annular partial regions 16al and 16a2, between which the compensating means 17 are arranged. The embodiment shown in FIG. 4 essentially corresponds to the embodiment shown in FIG. 1 with compensating means 17 in the form of a double-walled cylinder shell.

In the exemplary embodiment shown in FIG. 5, the compensating means 17 are arranged between the regions 16c of the fastening element 16 welded to the end faces of the filter walls 15 and the inner flange 16b. In this exemplary embodiment too, an expansion or contraction movement of the filter walls 15 and / or the regions 16c of the fastening element 16 is compensated for by the compensating means 17, for example due to temperature changes. In the embodiment shown in Figure 6 are first

Compensation means 17 between the outer flange 16a and the areas lβc of the fastening element 16 welded to the filter walls 15 and second compensation means 17 between the areas 16c and the inner flange 16b. In the exemplary embodiment shown in FIG. 3, the fastening element 16 has a material web folded three times in the region of the compensating means 17. The material web in the area of the compensating means 17 thus comprises four mutually spaced web sections 17a to 17d with three intermediate areas 18a to 18c formed between them. Any support means 19 and / or insulating means 20 can be arranged in the intermediate regions 18a to 18c according to the exemplary embodiments from FIGS. 7 and 8.

In other words, the fastening element 16 according to the exemplary embodiment shown in FIG. 3 is designed as a quadruple-walled cylinder shell.

All of the exemplary embodiments of the particle filter 11 according to the invention have in common that the regions 16c of the fastening element 16 welded to the end faces of the filter walls 15 are movable and that compensating means 17 are provided which prevent movements of the filter walls 15 and / or the regions

16c can lead to stresses and consequently to stress fractures of the weld seams between the filter walls 15 and the areas 16c. This can be achieved by any compensation means 17 and / or by any compensation means 17.

According to a further exemplary embodiment shown in FIG. 13, the compensating means 17, which is divided into sections 17a and 17b in FIG. 4, can be limited to a single part, a compensating element 27, whereby material and forming steps for the compensating means 17 are saved and less Radial expansion of the overall arrangement than the housing 3 can be achieved. The compensating element 27 has a crank 30 in order to establish the distance 31 between the filter wall 15 (shown in dashed lines) and the compensating element 27. The compensating element 27 is connected to the outer flange 16a of the fastening element 16. The one in radial

The part 12a of the housing 12 arranged in the fastening element 16 is at a distance 32 from the compensating element 27. The part 12b of the housing 12 oriented in the radial direction in the opposite direction has the same inside diameter as the compensating element 27. In this embodiment, all of the measures described above (beads in the compensating element 27, support means and / or insulating means in the intermediate region with the spacing 32 be present between the compensating element 27 and the part 12c of the housing 12).

Claims

Expectations

1. Particulate filter (11), in particular for exhaust gases from internal combustion engines, comprising a housing (12) and a filter body (13) arranged therein, the

Filter body (13) comprises a plurality of filter walls (15), which extend from a longitudinal axis (14) of the particle filter (11) and extend essentially in the radial direction and in the direction of the longitudinal axis (14) and are spaced apart from one another in the circumferential direction, and wherein the filter walls (15) are welded or soldered at least in some areas to their end faces with at least one fastening element (16) by means of which the filter body (13) is fastened in the housing (12), characterized in that the fastening element (16) between the fastening element (16 ) and the housing (12) acting compensating means (17), which movements the

Compensate filter walls (15) relative to the housing (12).

2. Particulate filter (11) according to claim 1, characterized in that the compensating means (17) are an integral part of the fastening element (16).

3. Particulate filter (11) according to claim 2, characterized in that the fastening element (16) has a radially outwardly directed outer flange (16a) on which the regions (16c) of the fastening element (16) welded to the filter walls (15) their from the Longitudinal axis (14) of the particle filter (11) facing away and which is fixed to the housing (12), the compensating means (17) between the outer flange (lβa) and the areas (16c) welded to the filter walls (15) Fastening element (16) are arranged.

4. Particulate filter (11) according to claim 2 or 3, characterized in that the fastening element (16) has a radially outwardly directed outer flange (16a) on which the regions (16c) of the fastening element (16) welded to the filter walls (15) ) are attached to their side facing away from the longitudinal axis (14) of the particle filter (11) and which is attached to the housing (12), the compensating means (17) between a first one attached to the housing (12) of the particle filter (11)

Area (16al) of the outer flange (16) and a second area (16a2) of the outer flange (16) fastened to the areas (16c) of the fastening element (16) welded to the filter walls (15).

5. Particulate filter (11) according to one of claims 2 to 4, characterized in that the fastening element (16) has a radially inwardly directed inner flange (16b) on which the areas (lβc) of the fastening element welded to the filter walls (15) (16) are fastened on their side facing the longitudinal axis (14) of the particle filter (11), with the compensating means (17) between those with the filter walls

(15) welded areas (16c) of the fastener

(16) and the inner flange (16b) are arranged.

6. Particulate filter (11) according to one of claims 3 to 5, characterized in that the fastening element (16) in the region of the compensating means (17) has a material web folded at least once.

7. Particle filter (11) according to claim 6, characterized in that the material web has a surface extension substantially transverse to the movements of the fastening element (16) to be compensated.

8. Particulate filter (11) according to claim 6 or 7, characterized in that the material web is folded once or three times.

9. particle filter (11) according to any one of claims 6 to 8, characterized in that in an intermediate region (18;

18a, 18b, 18c) between the folded web sections (17a, 17b; 17a to 17d) of the material web support means (19) are arranged.

10. Particulate filter (11) according to claim 9, characterized in that the support means (19) comprise a wave-shaped support plate.

11. Particle filter (11) according to one of claims 6 to 10, characterized in that in an intermediate region (18; 18a, 18b, 18c) between the folded web sections (17a, 17b; 17a to 17d) of the material web insulating means (20) are arranged are.

12. Particulate filter (11) according to claim 11, characterized in that the insulating means (20) comprise rock wool.

13. Particulate filter (11) according to one of claims 6 to 12, characterized in that at least in regions at least one inwardly curved bead (21) is formed on a radially inner folded web section (17a) of the material web.

14. Particulate filter (11) according to one of claims 1 to 12, characterized in that the filter walls (15) comprise a sintered metal.