EP0492418B1 - Apparatus for catalytic purification of exhaust gases, in particular exhaust gases from internal combustion engines - Google Patents

Description

The invention relates to a device for the catalytic detoxification of exhaust gases, preferably exhaust gases from internal combustion engines, consisting of a carrier matrix, two inner housing halves and two outer housing halves. Such a device is known from DE-A 39 22 667.

The aforementioned publication describes a device for exhaust gas purification, in which a ceramic carrier matrix is fastened in an inner shell with the aid of a mounting mat. This inner shell is installed in an outer housing for thermal insulation from the environment. The inner shell has no metallic contact with the outer housing, it is supported in this by continuous storage means. It is disadvantageous here that the fastening of the inner shell in the surrounding outer housing can only be carried out using complex storage means (wire mesh) or the like. is accomplished. The storage means are subject to constant mechanical and thermal stress during the life of the device, as a result of which they lose their storage function in whole or in part. This can shorten the life of the device. In addition, the manufacturing process is very complex. In the aforementioned prior art, the inner shell is equipped with a carrier matrix in a first production step, wrapped with holding elements in a further step, inserted into the outer housing in the next step and finally fixed there.

The US patent Re. 33,118 discloses two filter units or similar exhaust treatment units connected in series, a part of the exhaust gases passing the respective series units and a part being passed through them. Two inner half-shells are nested in each case, the inner half-shells having the filter unit or the like.

The invention has for its object to improve the construction of the generic exhaust gas purification device so that the effort in assembling the device is reduced, and that the storage of the inner housing in the outer housing is reliably ensured during the entire life of the device.

In addition, good thermal and acoustic insulation of the exhaust gas cleaning device from the environment is to be achieved.

This object is achieved by the device according to claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

This object is achieved in that two identical inner housing halves are provided with tabs which serve as spacers to an outer housing. In order to simplify the fixing of the inner housing in the outer housing at the same time, features are provided in the outer housing, in which the tabs of the inner housing engage. This simplifies the assembly of the device for exhaust gas purification in such a way that the carrier matrix is inserted into the inner housing halves, these are inserted into the outer housing halves and the outer housing halves are closed and joined by a joining connection. A work step to insert support material is no longer required.

The exhaust gases are passed through the carrier matrix in the inner half of the housing and a free annular space is formed between the inner housing and the outer housing, which also does not have any exhaust gases, whereby good thermal and acoustic insulation to the outside is achieved.

The effort required to manufacture the inner and outer housing halves can be reduced by making the inner and outer housing halves the same.

In an embodiment variant according to claim 2, the housing halves are provided with beads, preferably running in the circumferential direction. Such beads improve the stability of the housing, in particular the noise emission that emanates from the device during operation is reduced.

In a further embodiment variant according to claim 3, the space between the inner and the outer housing is closed by inserted sealing rings. This on the one hand keeps the hot exhaust gas flow away from the outer housing, and on the other hand at least one seal is required to prevent leakage of the exhaust gases between the inner and outer housing. The seals are ring-shaped executed and are inserted in forms of the outer housing halves that run in a semi-ring around the housing halves.

The housing halves are provided according to claim 4 with conical inflow and outflow areas. This greatly simplifies the installation of the device in an exhaust system, the diameter of the device for exhaust gas purification is reduced to the diameter of the connecting pipes.

According to claim 5, conical inlet and outlet funnels are used between the connecting pipes and the inner housing. These cones are pushed on the one hand on the connecting pipes that protrude into the outer housing, and on the other hand on the tube-like ends of the inner housing. A technical connection for fastening the cones is not necessary if the cones are pushed onto the pipes with a light press fit.

The outer housing halves are according to claim 6 by a circumferential joining connection, e.g. a roll seam, or a circumferential positive connection, e.g. sealed gas-tight by folding. The inner housing, which is supported by the side tabs in the features of the outer housing, is permanently and statically fixed by joining the outer housing halves.

The tabs are made in one piece with the inner housing halves and point radially outwards. They are larger in their axial length than in their radial length and are dimensioned according to the design requirements, for example the desired distance between the inner and outer housing. In order to prevent the inner housing from twisting in the outer housing, at least four tabs are provided on the inner housing halves; a larger number is only required for very long housings, since a gap could then arise between the inner housing halves.

Claim 9 describes an advantageous dimensioning of the gap between the inner and the outer housing.

The design of the mounting of the inner housing in the outer housing according to claim 10 allows the thermal expansion of the inner relative to the outer housing in the axial direction.

Additional insulation is proposed according to claim 11. Both the thermal and the acoustic separation of the inner housing from the outer housing is effected. Since the carrier matrix in the inner housing represents an obstacle to the exhaust gas flow, the pulsation of the exhaust gas flow is transmitted to the carrier matrix and the inner housing. The vibrating housing acts like a sound source. Insulation from the outer casing can reduce noise considerably.

According to claim 12, the inner housing is insulated from the outer housing by enveloping the tabs with an insulating material, for example wire mesh or ceramic cords, which surrounds the tabs in a ring. Under certain operating conditions, it is advantageous to place cap-shaped insulation elements on the tabs, so that the front ends of the tabs are also encased. Axially parallel beads are pressed into the features of the outer housing halves, into which the insulation material that surrounds the tabs engages, so that it is fixed around the tabs. The embossing depth of the beads is chosen so that the insulation material is pressed when the outer housing halves are placed one on top of the other. As a result, the inner housing is securely stored in the outer housing.

According to claim 13, the connecting pipes are insulated from the inner housing or the cones. Here, the insulating materials, for example wire mesh or ceramic cords, are inserted into annular beads which are embossed on the ends of the cones on the connecting tube side or on the ends of the connecting tubes. The insulation material also serves as a seal against escaping exhaust gases.

According to claim 14, the material consists of metallic or ceramic knitted fabrics, the like cords, caps or the like. is processed.

According to claim 15, the carrier matrix is a metal carrier matrix. The particular advantage of this embodiment is that the carrier matrix can be introduced into the inner housing halves without additional insulating material, so that no or very few insulating or holding materials are required for the entire manufacture of the device.

In claims 16 and 17 a further embodiment of the device is described, which is particularly suitable for the installation of a metal support matrix in the inner housing. The carrier matrix can be formed by a positive fit or by a joining connection, e.g. by soldering, to be fixed in the inner housing. If the carrier matrix is fixed in the inner housing by means of a technical connection, it may be necessary for the inner housing to be firmly closed in the outer housing before assembly, for example by spot welding on the edge of the inner housing halves.

Fig. 1

Draufsicht und Teilschnitt der Vorrichtung;

Fig. 2

Seitenansicht und Teilschnitt der Vorrichtung;

Fig. 3

Vorderansicht und Teilschnitt der Vorrichtung;

Fig. 4

Draufsicht und Teilschnitt der Vorrichtung mit isolierenden Elementen;

Fig. 5

Seitenansicht und Teilschnitt der Vorrichtung mit isolierenden Elementen;

und

Fig. 6

Vorderansicht und Teilschnitt der Vorrichtung mit isolierenden Elementen.

The invention is illustrated in the drawing using an exemplary embodiment and is described in more detail below. Show it:

Fig. 1

Top view and partial section of the device;

Fig. 2

Side view and partial section of the device;

Fig. 3

Front view and partial section of the device;

Fig. 4

Top view and partial section of the device with insulating elements;

Fig. 5

Side view and partial section of the device with insulating elements;

and

Fig. 6

Front view and partial section of the device with insulating elements.

The illustrated embodiment consists of outer housing halves 1, 1 'with inflow or outflow areas 101, 102, inner housing halves 2, 2', a carrier matrix 3, tabs 4, shapes 5, cones 6, 6 ', sealing rings 7, 7', Connection pipes 8, 8 ', beads 9, 9', semi-ring-shaped features 10, 10 ', an intermediate space 11 and a circumferential weld seam 12. The cross section of the support matrix 3, the cones 6, 6' and the connection pipes 8, 8 'is circular, the cross section of the housing halves is semicircular.

In Fig. 1 the top view of the device for exhaust gas purification is shown. The inner housing halves 2, 2 'are mounted in the outer housing halves 1, 1'. Here, the tabs 4 come to lie in the forms 5. By assembling the outer housing halves 1, 1 ', the tabs 4 of the inner housing halves 2, 2' are jammed in the formations 5, so that the inner housing halves 2, 2 'are statically determined in the outer housing halves 1, 1'. The outer housing halves 1, 1 'are connected to one another in their edge regions by a circumferential weld seam 12.

In this embodiment, the exhaust pipes 8, 8 'are welded in a ring shape to the outer housing halves 1, 1'. The welding takes place at the ends of the conical inflow and outflow regions 101, 102. The exhaust pipes 8, 8 'are a short distance into the circular openings which result from the joining of the outer housing halves 1, 1' at the ends , inserted.

2 shows the side view of the device for exhaust gas purification. Sealing rings 7, 7 'are inserted at the transitions from the inner housing shafts 2, 2' to the cones 6, 6 '. These sealing rings 7, 7 'are positively mounted in the semi-ring-shaped features 10, 10' of the outer housing halves 1, 1 '. They provide a gas-tight closure of the intermediate space 11 with respect to the entrance or

Outflow area of the device for exhaust gas purification is safe. In the cutting area, the mounting of the sealing rings 7, 7 'in the semicircular forms 10, 10' can be clearly seen. The definition of sealing rings 7, 7 'is further supported by the advantageous configuration of the beads 9' of the inner housing halves 2, 2 '. The cones 6, 6 'are inserted into the device for exhaust gas purification without any technical connections. They are pushed onto the exhaust pipes 8, 8 'at one end and onto the inner housing halves 2, 2' at the other ends.

In Fig. 3 the front view is shown with partial sections of the device for exhaust gas purification. In the right partial section, the intermediate space 11 for thermal insulation of the inner housing halves 2, 2 'and the carrier matrix 3 from the outer housing halves 1, 1' can be seen. The sections of Fig. 3 show that the inner housing halves 2, 2 'are connected to the outer housing halves 1, 1' only by the tabs 4, so that only these tabs 4 can cause a direct thermal connection.

4 shows the top view of the device for exhaust gas purification with insulating elements. The inner housing halves 2, 2 'are mounted in the outer housing halves 1, 1'. Here, 4 insulating rings 202 are wrapped around the tabs, which lie in beads 201 of the forms 5. By assembling the outer housing halves 1, 1 ', the insulating rings 202 are pressed around the tabs 4 of the inner housing halves 2, 2' and clamped in the beads 201 of the features 5, so that the inner housing halves 2, 2 'in the outer housing halves 1,1 'are statically determined. The outer housing halves 1, 1 'are connected to one another in their edge regions by a circumferential weld seam 12.

The exhaust pipes 8, 8 'are welded in a ring shape to the outer housing halves 1, 1'. The welding takes place at the ends of the conical inflow and outflow regions 101, 102. The exhaust pipes 8, 8 'are a piece in the circular openings which are located by joining the outer housing halves 1, 1 'at the ends. The inlet-side exhaust pipe 8 'is inserted into the cone 6', which has a circumferential bead 204 'on this side. The other side of the cone 6 'is pushed onto the inner housing halves 2, 2'. The exhaust pipe 8 on the outlet side, which has a circumferential bead 204 on this side, is pushed over the end of the cone 6 on the outlet side. The cone 6 is pushed on the input side onto the inner housing halves 2, 2 '.

5 shows the side view of the device for exhaust gas purification with insulating elements. The structure of the device corresponds to that of FIG. 2. In deviation from this, the position of the insulating elements 203, 203 'is shown. The exhaust pipe 8 'on the inlet side is inserted into the cone 6'. At its end, the insulating element 203 'is inserted into the bead 204'. The cone 6 'is supported on the exhaust pipe 8' via the element 203 'and is thermally and acoustically insulated from it. On the output side, the cone 6 is inserted into the exhaust pipe 8 with the circumferential bead 204 in which the insulating element 203 is inserted. The cone 6 is supported thermally and acoustically insulated via the element 203 in the exhaust pipe 8.

In Fig. 6 the front view is shown with partial sections of the device for exhaust gas purification with insulating elements. The construction of the device corresponds to that of FIG. 3. The sections of FIG. 6 show that the inner housing halves 2, 2 'are connected to the outer housing halves 1, 1' only by the insulating elements 202 via the tabs 4, so that there is no thermal or acoustic connection here.

Claims (17)

1. Apparatus for the catalytic cleaning of exhaust gases, preferably exhaust gases of internal combustion engines, comprising two outer casing halves (1, 1'), two inner casing halves (2, 2') and a carrier matrix (3) enclosed by the two inner casing halves (2, 2'), wherein the inner casing halves (2, 2') each have respective lateral plates (4) which positively lockingly engage into lateral outwardly pressed portions (5) of the outer casing halves (1, 1') and wherein the assembled inner casing halves (2, 2') are mounted in a statically defined manner in the assembled outer casing halves (1, 1'), characterised in that the exhaust gases are passed through the carrier matrix (3) and that there is fold a free annular space (11) through which only the lateral plates (4) pass in the peripheral direction of the outer and inner casing halves (1, 1', 2, 2') and through which exhaust gases do not flow.
2. Apparatus according to claim 1 characterised in that the outer casing halves (1, 1') and the inner casing halves (2, 2') have corrugations (9, 9').
3. Apparatus according to claim 1 or claim 2 characterised in that the outer casing halves (1, 1') have semi-annular outwardly pressed portions (10, 10') and fitted into said outwardly pressed portions (10, 10') are sealing rings (7, 7') which gas-tightly close off the space between the outer casing halves (1, 1') and the inner casing halves (2, 2').
4. Apparatus according to one of claims 1 to 3 with connecting pipes (8, 8') characterised in that the outer casing halves (1, 1') are provided with two conical inlet and outlet regions (101, 102) respectively and that the connecting pipes (8, 8') are connected by a joining procedure, preferably welded, to the inlet and outlet regions (101, 102) respectively.
5. Apparatus according to one of claims 1 to 4 with connecting pipes (8, 8') and cones (6, 6') characterised in that the cones (6, 6') are inserted between the connecting pipes (8, 8') and the assembled inner casing halves (2, 2') and that the cones (6, 6') are fitted at both sides on to the connecting pipes (8, 8') and the ends of the inner casing halves (2, 2') respectively.
6. Apparatus according to one of claims 1 to 5 characterised in that the two casing halves (1, 1') are gas-tightly connected by connections involving a joining procedure or positively locking connections.
7. Apparatus according to one of claims 1 to 6 characterised in that the inner casing halves (2, 2') have at least four plates (4) which face radially outwardly from the walls of the inner casing halves (2, 2').
8. Apparatus according to one of claims 1 to 7 characterised in that the axial length of the plate (4) is greater than its radial length.
9. Apparatus according to one of claims 1 to 8 characterised in that the plates (4) hold the inner casing halves (2, 2') spaced from the outer casing halves (1, 1') coaxially at a radial spacing of from 2 mm to 10 mm, preferably 6 mm.
10. Apparatus according to one of claims 1 to 9 characterised in that the bunting of a pair of the plates (4) which are disposed in opposite relationship on the periphery in the outwardly pressed portions (5) is in the form of a fixed mounting means while the other mountings in the axial direction are in the form of loose bunting means.
11. Apparatus according to one of claims 1 to 10 characterised in that the inner casing halves (2, 2') are thermally and acoustically separated from the outer casing halves (1, 1') by insulating elements (202, 203, 203').
12. Apparatus according to claim 11 characterised in that the insulating elements (202) are laid around the plates (4) and engage into corrugations (201) in the outwardly pressed portions (5) of the outer casing halves (1, 1') and that the assembled inner casing halves (2, 2') are mounted in a statically defined manner in the assembled outer casing halves (1, 1').
13. Apparatus according to claim 11 or claim 12 characterised in that the connecting pipes (8, 8') are thermally and acoustically separated fro the cones (6, 6') by insulating elements (203, 203') and that the insulating elements (203, 203') are mounted in corrugations (204, 204').
14. Apparatus according to one of claims 11 to 13 characterised in that the insulating elements (202, 203, 203') comprise metallic or ceramic mesh, preferably comprising ceramic cords.
15. Apparatus according to one of claim 1 to 14 characterised in that the carrier matrix (3) comprises wound or stacked metal foils.
16. Apparatus according to one of claim 1 to 15 characterised in that the carrier matrix (3) is mounted by a positively locking configuration in the inner casing halves (2, 2').
17. Apparatus according to one of claims 1 to 18 characterised in that the carrier matrix (3) is fixed in the inner casing halves (2, 2') by a connection involving a joining procedure.

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