EXHAUST GAS AFTERTREATMENT DEVICE

Abstract

A device for exhaust-gas aftertreatment, having a first, tubular flow path, having a diverting region and having a second, annular flow path. The tubular flow path is formed by an inner pipe and the annular flow path is, by an outer pipe running substantially parallel to the inner pipe, formed between the inner pipe and the outer pipe, and the diverting region is designed to divert the exhaust-gas flow from the tubular flow path into the annular flow path. The device has an annular catalytically active substrate body and an annular particle filter, wherein the substrate body and the particle filter are arranged in the annular flow path.

Claims

1. A device for exhaust-gas aftertreatment, having an inner pipe; a tubular flow path formed by the inner pipe; an outer pipe running substantially parallel to the inner pipe; an annular flow path formed between the inner pipe and the outer pipe; a diverting region which diverts the exhaust-gas flow from the tubular flow path into the annular flow path; an annular catalytically active substrate body; and an annular particle filter; wherein the substrate body and the particle filter are arranged in the annular flow path.

2. The device of claim 1, wherein the cross section of the first flow path narrows or widens conically in the flow direction.

3. The device of claim 1, wherein the cross section of the second flow path narrows or widens conically in the flow direction.

4. The device of claim 1, wherein the inner pipe and the outer pipe are arranged concentrically with respect to one another.

5. The device of claim 1, wherein the particle filter is arranged downstream of the catalytically active substrate body in the flow direction.

6. The device of claim 1, further comprising: a second particle filter arranged in the diverting region; wherein the particle filter in the diverting region is more coarsely porous than the annular particle filter in the annular flow path.

7. The device of claim 6, the second particle filter in the diverting region further comprising a coating of a wall region.

8. The device of claim 7, the diverting region further comprising a cover-like element which is connected in gas-tight fashion to the outer pipe.

9. The device of claim 8, the cover-like element further comprising: a baffle wall in the interior of the annular catalytic converter; wherein the baffle wall has a coating that acts as a particle filter.

10. The device of claim 1, wherein the annular particle filter has a cross section that widens or narrows conically in the flow direction.

11. The device of claim 1, the annular particle filter further comprising a filter matrix which has a cross section that narrows or widens in the flow direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The invention will be explained in detail below on the basis of an exemplary embodiment and with reference to the drawing. In the drawing:

[0027] FIG. 1 shows a sectional view through an annular catalytic converter, wherein the tubular flow path, the diverting region, the annular flow path and the catalytic converters and particle filters arranged therein are illustrated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0029] FIG. 1 shows an annular catalytic converter 1. This has a centrally situated first, tubular flow path 2 through which exhaust gas may flow along the throughflow direction 3. The tubular flow path 2 is delimited in the radial direction by an inner pipe 4. Arranged downstream of the tubular flow path 2 in the flow direction 3 is the diverting region 5.

[0030] The diverting region 5 is formed from a cover-like element 6, which is impinged on by the exhaust gas flowing through the tubular flow path 2. The impingement against the cover-like element 6 causes the exhaust gas to be diverted outward in the radial direction and finally directed in a flow direction 7 which is opposite to the throughflow direction 3 by 180 degrees.

[0031] The exhaust gas then flows through the second, annular flow path 8 through multiple elements for exhaust-gas aftertreatment arranged in this flow path 8. FIG. 1 shows an annular catalytic converter 9 which, for example, has a catalytically active coating in order to thus be able to promote the reaction of the exhaust gas. Arranged downstream of the catalytic converter 9 is a particle filter 10, which is provided for filtering the exhaust gas that has flowed through the catalytic converter 9.

[0032] The catalytic converter 9 and the particle filter 10 are each of annular construction.

[0033] The second annular flow path 8 is delimited inwardly in the radial direction by the inner pipe 4 and outwardly in the radial direction by the outer pipe 12.

[0034] In FIG. 1, the inner pipe 4 and the outer pipe 12 are arranged concentrically and parallel with respect to one another. This results in an annular gap between inner pipe 4 and outer pipe 12 that remains constant in the circumferential direction. As already described, conical pipes may also be used here and, if necessary, a non-concentric arrangement of the pipes with respect to one another may also be selected.

[0035] A filter layer 11 is arranged on the inner wall of the cover-like element 6 in the diverting region 5, which filter layer acts as a coarse filter for the particles entrained in the exhaust gas. The filter layer 11 is in this case is more coarsely porous than the particle filter 10. The aim of the filter layer 11 is to pre-filter the exhaust gas in order to subsequently prevent a blockage of the catalytic converter 9 or of the particle filter 10, which is more finely porous than the filter layer 11.

[0036] As an alternative to a type of coating of the inner wall of the cover-like element 6, a honeycomb body acting as a filter may also be introduced into the diverting region 5. The pressure loss caused by the filter layer 11, and the adverse influence on the gas flow, is very small. For the most optimum possible action of the catalytic converter and of the particle filter, it is sought to achieve as homogeneous a flow distribution as possible over the cross section of the flow paths 2, 8, and also as uniform as possible a concentration distribution of the exhaust gas.

[0037] The exemplary embodiment in FIG. 1 is not of a limiting nature, and serves for illustrating the concept of the invention.

[0038] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.