METHOD FOR IMPROVING THE COATING OF A HONEYCOMB BODY WITH A CATALYTICALLY ACTIVE COATING

Abstract

A method for producing a device for the aftertreatment of exhaust gases and for coating a honeycomb body, provided in the device, with a catalytically active surface coating. The honeycomb body is formed from a multiplicity of metallic, at least partially structured foils stacked one on another and wound so that the honeycomb body forms a multiplicity of flow channels through which fluid can flow along a main flow direction. The honeycomb body is received in an inner casing and is durably connected thereto. The inner casing is arranged in an outer casing serving as a housing and is durably connected thereto. Before the introduction of the catalytically active coating into the flow channels formed by the honeycomb body, an air gap or air gaps, which have been formed between the outer casing and the components arranged therein, are filled by a filler.

Claims

1.-6. (canceled)

7. A method for producing a device for aftertreatment of exhaust gases and for coating a honeycomb body, provided in the device, with a catalytically active surface coating, comprising: forming the honeycomb body from a multiplicity of metallic, at least partially structured foils which are stacked one on another and wound so that the honeycomb body forms a multiplicity of flow channels through which fluid can flow along a main flow direction; receiving the honeycomb body in an inner casing; durably connecting the honeycomb body to the inner casing; arranging and durably connecting the inner casing in an outer casing; introducing the catalytically active surface coating into the multiplicity of flow channels formed by the honeycomb body; and filling an air gap or air gaps formed between the outer casing and at least the inner casing with a filler before the introducing the catalytically active surface coating into the multiplicity of flow channels.

8. The method as claimed in claim 7, wherein the filler is a gel-like organic composition.

9. The method as claimed in claim 7, wherein the filler is introduced into the air gap or air gaps before the device is subjected to a heat treatment, for example drying or calcining.

10. The method as claimed in claim 7, wherein the filler is removed from the air gap or air gaps after the introducing the catalytically active surface coating.

11. The method as claimed in claim 10, wherein the filler is removed from the air gap or air gaps by a thermal process.

12. The method as claimed in claim 7, wherein the filling of the air gap or air gaps is carried out such that an opening cross section facing toward an introduction site through which the catalytically active surface coating is introduced is sealed by the filler.

13. The method as claimed in claim 9, wherein the heat treatment is at least one of drying or calcining.

14. The method as claimed in claim 7, wherein the outer casing is configured as a housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention will be explained in detail below on the basis of an exemplary embodiment with reference to the drawing. In the drawing:

[0026] The FIGURE is a sectional view through a honeycomb body received in an outer casing, the air gap formed between the inner casing of the honeycomb body and the outer casing being filled with a filler.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS the

[0027] FIGURE shows a device for exhaust gas aftertreatment in a sectional view. Arranged centrally, there is a honeycomb body 1 formed from a metallic matrix. The honeycomb body 1 is received in an inner casing 2, which fixes the matrix, protects it against spreading out and uncoiling, and at the same time protects the matrix against mechanical influences. Honeycomb bodies of this design are known in a wide variety of forms in the prior art.

[0028] In the depiction of the FIGURE, the honeycomb body 1 is preceded by a heating disk 3, which is connected to the honeycomb body 1 by supporting pins 4. The heating disk 3 is connected to a voltage source via the electrical bushing 5 shown and can therefore be energized, so that heating is achieved.

[0029] The honeycomb body 1 with its inner casing 2 is inserted into an outer casing 6 and is durably connected thereto, for example by soldering. An air gap 7 is formed between the outer casing 6 and the inner casing 2. This air gap may be created deliberately as a result of the constituent part geometry, or else may be formed as a result of tolerances between the constituent parts. Air gaps are in principle also conceivable between all components of the device.

[0030] In the FIGURE, the air gap 7 is filled by a filler 8 so that nothing can enter the air gap 7, particularly from the side facing toward the heating disk 3.

[0031] The washcoat with which the matrix of the honeycomb body 1 is coated is for example pressed with positive pressure into the honeycomb body and/or drawn through the latter with negative pressure. The honeycomb body 1 may also be flushed with the washcoat. In all these methods, it is highly likely that the washcoat would penetrate into the air gap 7 if the latter is not sealed.

[0032] The filler may, for example, be introduced deliberately into the air gap 7 by an injection needle in order to fill it, and in particular to fill the open cross section.

[0033] The FIGURE is in particular not of a limiting nature, and serves to illustrate the concept of the invention.

[0034] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.