WO2007012509A1

WO2007012509A1 - Filter device, especially particulate filter for an exhaust gas system of an internal combustion engine

Info

Publication number: WO2007012509A1
Application number: PCT/EP2006/062770
Authority: WO
Inventors: Martin Eggenmueller; Klaus-Dieter Sulzberger; Thomas Hauber; Markus Wolff; Siegbert Griesinger; Holger Dietzhausen; Thomas Lehmann
Original assignee: Robert Bosch Gmbh
Priority date: 2005-07-25
Filing date: 2006-05-31
Publication date: 2007-02-01
Also published as: DE102005034603A1

Abstract

Disclosed is a filter device (16), especially a particulate filter for an exhaust gas system of an internal combustion engine, which filters particles out of a gas flow (26). Said filter device (16) comprises a housing (17) and a filter structure (22) with a plurality of filter pockets (24). At least one preloaded elastic damping element (46, 48) rests against the filter structure (22).

Description

Filter device, in particular particulate filter for an exhaust system of an internal combustion engine

State of the art

The invention relates to a filter device, in particular a particle filter for an exhaust system of an internal combustion engine, according to the preamble of claim 1.

A filter device of the type mentioned is known from DE 102 23 452 Al. At the shown there

Filter device is a particulate filter for an exhaust system of a diesel internal combustion engine. The filter walls in the known filter device are made of sintered metal and arranged so that wedge-shaped filter bags are formed. The tapered wedge edges of the filter pockets show against the flow direction of the exhaust gas, seen in the flow direction rear narrow side of a filter side is open.

The filter bags are arranged next to each other so that an overall annular filter structure is formed. The individual filter bags are kept at their respective axial ends. In operation, the exhaust gas passes through the side walls of the filter pockets, thereby retaining soot particles contained in the exhaust gas. Object of the present invention is to develop a filter device of the type mentioned so that it has a long life.

This object is achieved by a filter device having the features of claim 1. Advantageous developments are specified in subclaims.

Advantages of the invention

By at least one resilient damping element is applied to the filter structure, vibrations are transmitted from the housing to the filter structure only damped. The filter structure is thus exposed only to reduced vibration loads, which has a favorable effect on their life.

By jamming the damping element complex additional support structures can be avoided, which simplifies the production.

Particularly suitable is a damping element which comprises a knitted wire or is made of such, since such made of a high temperature resistant metal wire and by selecting the wire thickness and the density of the metal knit spring properties can be very well adapted to the individual requirements. A manufacturing method for an annular damping element is, for example, first to produce a wire tube by knitting, and then press this in the axial direction on a mandrel in shape.

It is within a single damping element and the combination of wire knit different Stiffness possible. For example, a "core" of the damping element may be made of a high stiffness wire mesh, whereas the outer contact area is made of a reduced stiffness wire mesh. In this way we realized a "softer" storage of the filter bags.

Due to the mostly cylindrical configuration of the filter structure and of the housing of the filter device, a ring-shaped damping element is particularly effective. Especially in such a ring receiving sections can be introduced, in which the corresponding edge regions of individual filter bags are positively received. Vibrations of the filter bags are particularly well damped in this way, without high surface forces occur at the contact points.

For mounting, it is helpful if an annular damping element is formed with a slot, since it can be expanded in this case, for example, for mounting. By obliquely configured wall surfaces in the region of the slot, an interruption of the contact with the housing and the filter structure is prevented or at least reduced. Nevertheless, a full fitting

To ensure damping element on the filter structure and / or on the housing, the inherent elasticity of the damping element can be supported by a spring element.

The arrangement of a damping element in the axial center of the filter structure, or by the arrangement of a plurality of damping elements in the axial direction, natural frequency and associated vibration amplitudes can be favorably influenced. This is especially true in a support in about over the entire axial length of the filter structure. In order to ensure the desired position of the damping element over the entire life of the filter device, this can be supported axially, for example, by corrugations on the housing or on the filter structure. Such beads can be introduced in the formation of the filter structure or the housing in a simple and cost-effective manner.

drawings

Hereinafter, particularly preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. In the drawing show:

Figure 1 is a schematic representation of a

Internal combustion engine with a filter device;

Figure 2 is a partial longitudinal section through a portion of the filter device of Figure 1;

Figure 3 is a perspective view of some

Elements of Figure 2;

Figure 4 is a plan view in the axial direction of the in

Figure 2 shown portion of the filter device;

Figure 5 is a plan view of a damping element of the filter device of Figure 1;

Figure 6 is a plan view of another damping element of the filter device of Figure 1;

Figure 7 is a plan view of an alternative Embodiment of a damping element;

Figure 8 is a plan view of yet another alternative

Embodiment of a damping element;

Figure 9 is a side view of yet another alternative embodiment of a damping element; and

Figure 10 is a side view of yet another alternative embodiment of a damping element.

Description of the embodiments

An internal combustion engine carries the reference numeral 10 as a whole in FIG. 1. It comprises an engine block 12 and an exhaust pipe 14, in which a filter device 16 is arranged. This serves in particular to filter out soot particles from the exhaust gas flow. The filter device 16 comprises a housing 17 with an outer housing 18, and an inner tube 20 shown in phantom only in FIG. 1, which is therefore an area of the housing 17.

As can be seen from FIGS. 2 and 3, a filter structure 22 is held in the inner tube 20. This comprises a plurality of wedge-shaped filter pockets 24, of which only one is shown in FIG. 3 for reasons of illustration. The filter pockets 24 have a closed end 28 which tapers counter to the direction of flow (arrow 26), and a narrow side 30 which is open in the flow direction 26 and is open. Radially inside filter walls 31a and 31b abut each other (reference numeral 32), whereas they are initially spaced apart on the radial outer side, before they merge in the region of the narrow side 30 in a rounding 36 into each other. The Filter bag 24 are made of a porous sintered metal.

The rear end 30 of the filter pockets 24, as seen in the flow direction 26, is held by an outer ring 38 and an inner ring 40. The outer ring 38 is in turn welded to the inner tube 20. The connection of the outer ring 38 with the filter pockets 24 and the inner ring 40 with the filter pockets 24 by welding. With the inner ring 40, a lid-like end flange 42 is connected.

The front end 28 of the filter pockets 24, as seen in the flow direction 26, is welded to a retaining ring 42 shown only in FIG. 2, which engages approximately at half the radial height of the filter pockets 24. The retaining ring 42 is also rigidly connected to the inner tube 20 via a retaining structure 44 of no interest here.

In operation, the filter structure 22 is flowed through in the flow direction 26 by the exhaust gas. In this case, the exhaust gas flow passes through the filter walls 31a and 31b, wherein deposited on the outside of the filter pockets 24 in the exhaust gas flow soot particles. The purified gas stream exits the filter structure 22 at the open narrow sides 30 of the filter pockets 24.

In order to reduce vibrations of the individual filter pockets 24, the filter structure 22 comprises a radially inner damping element 46, and a radially outer

Damping element 48. The inner damping element 46 is designed as a closed ring, which is made of a wire mesh. In the variant of a filter structure 22 shown in FIG. 2, the inner damping element 46 is simply in the radial direction inner edge 32 of the filter pockets 24 formed opening 50 is inserted, and it is biased with its radially outer boundary surface 52 at the inner edges 32 of the filter pockets 24 at. Seen in the axial direction of the filter structure 22 is the inner

Damping element 46, seen in the flow direction 26, about one third of the length of the filter structure 22. In this position, the inner damping element 46 is held by radially extending tabs 54a and 54b, which are present on some or all filter pockets 24.

In the variant of a filter structure 22 shown in FIG. 3, the inner damping element 46 is pushed onto a tube 56, which extends from the inner ring 40. In this case, the inner damping element 46 is also clamped under pretension between the inner tube 56, which ultimately can be counted as belonging to the housing 17, and the filter structure 22.

The outer damping element 48 is also off

Made knitted wire and clamped in the form of a ring between the curves 36 of the filter pockets 24 and the inner tube 20. The curves 36 of the filter pockets 24 are positively received in corresponding receiving portions 58 of the outer damping element 48. For axial retention of the outer damping element 48, two beads 60a and 60b are present in the inner tube 20.

The basic principle of the vibration-damping support of the filter pockets 24 (of which for reasons of illustration, only one is provided with a reference numeral) by the damping elements 46 and 48 can be seen again in Figure 4, which provides a simplified axial view of particularly essential components. One recognizes from this representation as well as from the representation in figure 5, in which the outer damping element 48 is shown enlarged again that the present in this receiving portions 58 may be more pronounced recesses than in the damping element 48 shown in Figure 3

Filter bags 24 in total as well as the filter walls 31 a and 31 b particularly effectively damped.

Alternative embodiments of damping elements are shown in FIGS. 6, 1 and 8 using the example of an inner one

Damping element 46 shown: In all three variants, the annular damping element 46 is provided with a slot 62 in the manner of a clamping ring. The mutually facing boundary surfaces of the slot 62 carry in FIGS. 6 to 8 the reference numerals 64a and 64b. Between a radius line 66 and the boundary surfaces 64, an angle A is present.

By virtue of the presence of the slit 62, the damping element 46 can, for example, be elastically compressed during assembly in the application shown in FIG. 2, so that it can be easily brought into its axial position between the two straps 54a and 54b. Due to its spring elasticity, the damping element 46 relaxes again when it is positioned, so that it bears against the inner edges 32 of the filter pockets 24 under prestress and can effectively damp vibrations there. To support these elastic spring properties can, as is apparent from Figure 7, in the damping element 46, a spring element 68, for example, be incorporated in the form of a spring plate.

The damping element 46 shown in FIG. 8 has a first section 70 forming a "core" of one A knit fabric having a first stiffness and a "wrapping" forming second portion 72 of a knit fabric having a second stiffness. The wrapping 72 forming wire knit is softer (lower stiffness) than that of the core 70. This allows the envelope 72 to adapt to the inner edges 32 of the filter pockets 24 and "snuggle", resulting in a correspondingly soft or gentle storage of Filter bags 24, while still providing sufficient bias provided by the core 70. The lower stiffness of the sheath 72 may be provided, for example, by using a thinner wire knit and / or a lower density wire knitted fabric The sheath 72 may only be on the radially outer side be provided of the core 70, as shown in Figure 8, or even the core surrounded on all sides.

FIGS. 9 and 10 show a further variant of an inner damping element 46. In this embodiment, the inner damping element 46 extends over approximately the entire length of the filter structure 22 and thus replaces the tube 56 shown in FIG. 3. It can be seen from FIG. that in this case the inner damping element is made of a relatively coarse wire mesh, so that a "porous" tube 56 is formed. A region of such a pipe 56 is indicated in Figure 2 on the right side.

By such over the entire axial length of the

Filter structure 22 extending inner damping element 46, the inner edges 32 of the filter pockets 24 are particularly evenly supported. An alternative to this is a plurality of damping elements 46 with a small axial extent, which extend over the axial length of the filter structure 22 are arranged distributed. As in the case of the damping element 46 shown in FIG. 8, the damping element 46 shown in FIG. 9 may also have a rather stiff core 70 and a rather soft sheath 72, as indicated in FIG.

Claims

02. 06. 2005Robert Bosch GmbH, 70442 Stuttgart claims

A filter device (16), in particular a particle filter for an exhaust system (14) of an internal combustion engine (10), which filters out particles from a gas stream (26), with a housing (17), and with a filter structure (22) with a plurality of filter pockets (24), characterized in that on the filter structure (22) at least one resilient damping element (46, 48) bears under prestress.

Second filter device (16) according to claim 1, characterized in that the damping element (46, 48) between the housing (17) and the filter structure (22) is clamped.

3. Filter device (16) according to one of claims 1 or

2, characterized in that the damping element (46, 48) comprises a wire mesh.

4. Filter device (16) according to claim 3, characterized in that the damping element (46) comprises a first portion (70) having a wire mesh having a first stiffness and a second portion (72) having a wire mesh having a second stiffness.

5. Filter device (16) according to one of the preceding claims, characterized in that the filter structure

(22) Overall, a cylindrical outer contour and the Housing (17) has a corresponding, radially outside of the filter structure (22) lying region (20), and that the damping element (48) is configured annular and clamped between the filter structure (22) and the outer region (20).

6. Filter device (16) according to one of the preceding claims, characterized in that the filter structure

(22) has a radially inner and axially extending opening (50) and the housing (17) has a corresponding region (56) lying radially inside the opening, and in that the damping element (46) is configured annularly and between the filter structure (22) and the inner region (56) is jammed.

7. Filter device (16) according to any one of claims 5 or 6, characterized in that the damping element (48) on its the filter pockets (24) facing side receiving portions (58) for preferably positive reception of the damping element (48) facing edge regions (36 ) of the filter bags (24).

8. Filter device (16) according to any one of the preceding claims, characterized in that the damping element (46) is designed as a clamping ring with a slot (62) whose boundary surfaces (64) relative to a radius line (66) preferably at an angle (A) ,

9. Filter device (16) according to claim 8, characterized in that the damping element (46) has a spring element (68), in particular a spring plate.

10. Filter device according to one of the preceding claims, characterized in that, in the axial

Direction seen, a plurality of similar damping elements are present.

11. Filter device (16) according to any one of the preceding claims, characterized in that extending at least one damping element (46) approximately over the entire axial length of the filter structure (22).

12. Filter device (16) according to one of the preceding claims, characterized in that the damping element (46; 48) by at least one holding portion (54; 60), in particular a bead, is axially supported on the housing (20) and / or the filter structure (22) is present.