EP0789807B1 - Catalyst carrier element with internal insulation - Google Patents

Abstract

For the catalytic reaction of exhaust gases in an exhaust system, in particular an exhaust system for use in internal combustion engines, a device is proposed with a catalyst carrier element (1) which is provided with a plurality of channels (2) through which the exhaust gas can flow. The free cross section (4) of flow of the channels (2) is partially closed in the direction of flow of the exhaust gas by plastic deformation of the channel walls (11), specifically, in an outer ring region (3) of the catalyst carrier element (1). The plastic deformation can be carried out using, for example, a tool (17) provided for this purpose with a disc (18) which can rotate about an axis (19). The disc (18) is forced against the catalyst carrier element (1) and the casing (10) to create a plastic deformation of the casing tube (10) and channel walls (11) in the form of a peripheral crimp (20) pointing towards the carrier element (1). Other techniques can be applied to create the plastic deformation. The outer channels thus closed off form a thermal insulation against the casing tube (10) which helps the catalyst carrier element (1) to heat up more rapidly in the cold start phase.

Description

The invention relates to a device for catalytic conversion of exhaust gases in an exhaust system, in particular in an exhaust system of internal combustion engines, with a catalyst carrier body, of a plurality of channels through which an exhaust gas can flow has and on a method for producing such a device.

To ensure the most complete implementation possible in an internal combustion engine contained hydrocarbons and carbon monoxide To achieve, the catalyst must have a minimum temperature at which the catalytic conversion of the components of the exhaust gas take place can. In general one speaks of a so-called light-off temperature. The catalytic converter is in the cold start phase by the hot exhaust gas heated up. It is also known to at least support the catalyst carrier partially heated electrically. So that the pollutant emissions during the Cold start phase is as low as possible and for mechanical reasons therefore, it has been proposed to use a catalyst carrier body Form internal insulation to reduce heat loss to the housing and reduce the environment.

DE 36 02 134 A1 describes a device for catalytic Implementation of exhaust gases in an exhaust system, especially in one Exhaust system of internal combustion engines, known to one in a metallic catalyst carrier body arranged in a housing having. The carrier body has a plurality of exhaust gases through which an exhaust gas can flow Channels on. The interior insulation of the catalyst carrier body According to the proposal of DE 36 02 134 A1, that in front of the catalyst carrier body a radially inward Collar is arranged, the collar height of 3-15% of the catalyst diameter, is at least 1 mm. Through this covenant a vortex zone is created in the exhaust gas flow, through which a direct admission an outer annular region with the hot exhaust gas is avoided.

DE G 87 12 267.7 U1 is a device for catalytic Implementation of exhaust gases in an exhaust system known. The device includes a catalyst carrier body having a plurality of flow channels for an exhaust gas and in a sleeve-shaped housing is inserted. The housing is opposite the catalyst carrier body thermally insulated. The insulation is achieved in that the Catalyst carrier body is arranged between end rings, which at least the outer layer of the metallic matrix body and thus the Seal the outer flow channels in this matrix. This creates in the outer area of the catalyst carrier body a closed, Air gap not flowed through by exhaust gas, which is used for thermal insulation.

The present invention has for its object the known To further develop devices for the catalytic conversion of exhaust gases, that the production of a catalyst carrier body with a Internal insulation is simplified. Furthermore, a method of manufacture is said to such a device for the catalytic conversion of exhaust gases to be provided.

This object is achieved by a device with the features Claim 1 solved. Advantageous further developments are the subject of Subclaims.

In contrast to the known devices for catalytic conversion Exhaust gases become in the outer area of the catalyst carrier body closed air gap not by additional rings or the like causes, but in that the free flow cross-section of the channels partially, d. H. in at least one axial section, in Flow direction of the exhaust gas due to plastic deformation of the duct walls is closed. This simplifies the manufacture of the Device, since now no collar or end ring in the housing must be introduced. The catalyst carrier body consists of several coiled sheet layers, the plastic deformation can already done while winding. This simplifies the manufacturing process more complicated Catalysts because of the winding process and the plastic deformation can be done simultaneously.

The channels are preferably closed in the region of the exhaust gas inlet. The plastic deformation of the channels advantageously takes place before the application of a catalytically active layer on the catalyst carrier body. The coating and (washcoat) is usually by means of a applied suspension flowing through the catalyst support body. Of the Catalyst support body can be arranged so that the suspension flows into the channels closed on one side. The washcoat then fills the channels out. It forms thermal insulation. If you arrange that Catalyst carrier body so that the closed channels in the inlet area the suspension are in the catalyst carrier body, so the channels cannot be filled with the suspension. This improves the insulation, since the thermal conductivity of the catalyst support layer, that would fill the channel completely is better than that in the Channels contained atmosphere. The channels are advantageously in the Exhaust gas inlet and exhaust area closed. Should the plastic Deformation does not completely close off individual channels, this will through the subsequent coating that closes the small gaps, balanced.

In a device in which the channels in the catalyst carrier body are formed in layers one above the other, it is advantageous in up to five Layers of the channels should be closed by plastic deformation, preferably two. This is an advantageous compromise between the necessary catalytically active surface and thermal insulation achieved without that the catalyst carrier body in its outer dimensions essential must be enlarged.

A method according to the invention for producing a device for catalytic conversion of exhaust gases in an exhaust system is carried out by the features of claim 5 specified. Advantageous further training the method are the subject of dependent claims 6 to 17.

According to the method, plastic deformation is proposed of the channels in an outer ring in the region of the catalyst carrier body the free flow cross section of the channels partly in the direction of flow to close the exhaust gas. The plastic deformation can in that the catalyst carrier body in a matrix is kicked in. When the catalyst carrier body is pushed in, the outer area of the support body deformed, thereby closing the channels will. The insertion die can be made with a conical or be provided with an annular wall.

Instead of pushing the catalyst carrier body into a die, the plastic deformation of the channel walls also take place in that exerted a force on an outer ring area by means of a stamp which leads to the plastic deformation of the channel walls. Of the Stamp can be ring-shaped or with an oblique from the inside out outside wall be formed. Is the stamp with a wall that runs diagonally from the inside to the outside the free flow cross sections of the channels by bending the channel walls closed. In the case of an annular stamp, the channel walls bruised.

According to a further advantageous idea, it is proposed that during the plastic deformation on the catalyst carrier body to hold its end opposite to the introduction of force. This has the advantage that the individual layers of the catalyst carrier body not be moved against each other.

Catalyst support bodies are known which are composed of a large number of themselves alternating structured and preferably smooth sheet metal layers exist. Such metallic catalyst carrier bodies are made by one Surround the casing tube. It is therefore proposed the plastic deformation of the casing tube and the channels in an outer ring area perform the catalyst carrier body so that the free flow cross section of the channels partly in the flow direction of the exhaust gas is closed. The plastic deformation of the casing tube and the Channels can be made in that at least one in the jacket tube inward circumferential bead is formed. The bead can also for connecting the catalyst carrier body to a housing be used.

The plastic deformation is advantageously carried out by free molding. The plastic deformation is preferably carried out by rolling or kneading carried out.

Figur 1

schematisch einen Katalysator-Trägerkörper und eine Matrize,

Figur 2

zeigt eine zweite Form einer Matrize,

Figur 3

zeigt schematisch einen Trägerkörper, welcher in eine Matrize nach Figur 2 eingestoßen wurde,

Figur 4

zeigt einen Katalysator-Trägerkörper und einen Stempel im Schnitt,

Figur 5

ein zweites Ausführungsbeispiel eines Stempels,

Figur 6

zeigt einen plastisch deformierten Trägerkörper, entsprechend Figur 4,

Figur 7

einen plastisch deformierten Trägerkörper durch Deformation mit einem Stempel nach Figur 5 und

Figur 8

einen Trägerkörper im Teilschnitt.

Further features and advantages of the subject matter of the invention are explained on the basis of exemplary embodiments, without being restricted to these exemplary embodiments. Here shows:

Figure 1

schematically a catalyst support body and a matrix,

Figure 2

shows a second form of a die,

Figure 3

schematically shows a carrier body which was pushed into a die according to FIG. 2,

Figure 4

shows a catalyst carrier body and a stamp in section,

Figure 5

a second embodiment of a stamp,

Figure 6

shows a plastically deformed carrier body, corresponding to Figure 4,

Figure 7

a plastically deformed carrier body by deformation with a stamp according to Figure 5 and

Figure 8

a carrier body in partial section.

The catalyst carrier body 1 has a plurality of exhaust gases flow-through channels 2. The channels 2 are alternating Arrangement of structured sheet metal layers 12 and smooth sheet metal layers 13 educated. Each channel has a free flow cross section 4, the is limited by the channel walls 11. The canal walls are covered by the sheet metal layers 12, 13 formed. For plastic deformation in one outer annular region 3 of the catalyst carrier body 1 this, as can be seen from FIG. 1, pushed into a die 7. For this purpose, the catalyst carrier body 1 z. B. by means of not shown Clamping jaws held and pushed into the die 7 accordingly will. In the illustration according to FIG. 1, the honeycomb body 1 is by means of a tool 14 pushed into the die. In the die 7 is an annular wall 8 is formed. The width of the ring corresponds the width of the channels to be closed in the honeycomb body 1. To the Wall 8 is followed by a jacket 15, the inner contour of which corresponds to the outer contour of the catalyst carrier body 1.

FIG. 2 shows a second exemplary embodiment of a die 7 shown. The die 7 has a wall 8 which is conical is.

A honeycomb body 1 is shown in FIG Die 7 was pushed in according to Figure 2. In the ring-shaped Area 3, channels 2 are closed. The edge area of the carrier body 1 is designed obliquely.

Instead of pushing the carrier body 1 into the die 7, it is proposed that the plastic deformation of the channels 2 by means of a stamp 9 or 9 'to close. The stamp 9 or 9 'can be moved back and forth and has an annular shoulder 16.

The stamp 9 'differs from the stamp 9 in that this has a wall 21 which extends obliquely from the inside to the outside.

6 and 7 support bodies 1 are shown, in which Figure 6 shows a carrier body in section, in which in the outer In the ring area, the channels 2 have been closed by means of the stamp 9 are. FIG. 7 shows a carrier body in which a stamp 9 'according to FIG. 5 was used.

The manufacture of the device for the catalytic conversion of Exhaust gases in an exhaust system, especially in an exhaust system for Internal combustion engines, with one surrounded by a casing tube 10 Catalyst carrier body 1, which has a plurality of channels 2 has, can be produced in that the plastic deformation of the casing tube 10 and the channels 2 in an outer ring region 3 takes place so that the free flow cross section 4 of the channels 2 partially is closed in the flow direction of the exhaust gas. The plastic one Deformation can take place by means of a tool 17. The tool 17 has a disk 18 which can be rotated about an axis 19 and which its outer edge region is essentially triangular Has cross section. The disc 18 is with a force against the Catalyst carrier body 1 and the jacket 10 pressed so that a plastic deformation of the casing tube 10 and the channel walls he follows. There is a circumferential bead 20 directed towards the carrier body 1 generated.

The tool 17 can rotate around the catalyst carrier body 1. It it is also possible to arrange the tool 17 stationary and the catalyst carrier body 1 to rotate around its axis.

The formation of the bead 20 can be done in stages, for which the tool 17 is delivered accordingly.

REFERENCE SIGN LIST

1

Catalyst carrier body

2nd

channels

3rd

Ring area

4th

Flow cross-section

5

entry

6

exit

7

die

8th

Wall

9.9 '

stamp

10th

Casing pipe

11

Canal wall

12.13

Sheet layer

14

Tool

15

coat

16

ring

17th

Tool

18th

disc

19th

axis

20th

Surround

21

wall

Claims (17)

1. Apparatus for the catalytic conversion of exhaust gases in an exhaust gas system, in particular in an exhaust gas system of internal combustion engines, comprising a catalytic converter carrier body (1) having a plurality of passages (2) through which an exhaust gas can flow, characterised in that in an outer annular region (3) of the catalytic converter carrier body (1) the free flow cross-section (4) of the passages (2) is closed at least in a portion in the direction of flow of the exhaust gas by plastic deformation of the passage walls (11).
2. Apparatus according to claim 1 characterised in that the passages (2) are closed in the region of the exhaust gas inlet (5).
3. Apparatus according to claim 2 characterised in that the passages (2) are additionally closed in the region of the exhaust gas outlet (6).
4. Apparatus according to claim 1, claim 2 or claim 3 wherein the passages (2) are formed in layer-wise mutually superposed relationship characterised in that up to five layers, preferably two layers, of the passages (2) are plastically deformed.
5. A process for producing an apparatus for the catalytic conversion of exhaust gases in an exhaust gas system, in particular in an exhaust gas system of internal combustion engines, comprising a catalytic converter carrier body (1) having a plurality of passages (2) through which an exhaust gas can flow, characterised by plastic deformation of the passages (2) in an outer annular region (3) of the catalytic converter carrier body (1) so that the free flow cross-section (4) of the passages (2) is closed at least in a portion in the exhaust gas flow direction.
6. A process according to claim 5 wherein the catalytic converter carrier body (1) is pushed into a die (7) for deformation of the passages (2).
7. A process according to claim 6 characterised in that the catalytic converter carrier body (1) is pushed into a die (7) with a wall (8) of a conical configuration.
8. A process according to claim 6 characterised in that the catalytic converter carrier body (1) is pushed into a die (7) having an annular wall (8).
9. A process according to claim 5 characterised in that deformation of the passages (2) is effected by a ram (9, 9').
10. A process according to claim 9 characterised in that deformation is effected by an annular ram (9).
11. A process according to claim 10 characterised in that the annular ram (9') has a wall (21) which extends inclinedly from the inside outwardly.
12. A process according to one or more of claims 5 to 11 characterised in that the catalytic converter carrier body (1) is counter-held during the plastic deformation.
13. A process for producing an apparatus for the catalytic conversion of exhaust gas in an exhaust gas system, in particular in an exhaust gas system of internal combustion engines, comprising a catalytic converter carrier body (1) which is enclosed by a tubular casing (10) and which has a plurality of passages through which an exhaust gas can flow, characterised by plastic deformation of the tubular casing (10) and the passages (2) in an outer annular region (3) of the catalytic converter carrier body (1) in such a way that the free flow cross-section (4) of the passages (2) is closed at least in a portion in the exhaust gas flow direction.
14. A process according to claim 13 characterised in that at least one peripherally extending crease (20) which is directed towards the carrier body (1) is formed in the tubular casing (10).
15. A process according to claim 13 or claim 14 characterised in that the plastic deformation is produced by free shaping.
16. A process according to claim 15 characterised in that the plastic deformation is produced by rolling.
17. A process according to claim 15 characterised in that the plastic deformation is produced by kneading.

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