Device for after-treatment of exhaust gases from internal combustion engines

Abstract

Ceramic support bodies for the after-treatment of exhaust gases of internal combustion engines is provided. On a jacket of the support body heat-resistant elevations are subsequently applied that fix the bed against movement.

Description

This nonprovisional application claims priority under 35 U.S.C. § 119(a) to German Patent Application No. 20 2006 013 789, which was filed in Germany on Sep. 8, 2006, and which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to devices for the after-treatment of exhaust gases from internal combustion engines.

2. Description of the Background Art

In exhaust gas catalysts or soot particle filters, which use a ceramic support body, are held in a housing with the aid of a bed mat. This bed mat has the task of balancing out the differences in thermal expansion of ceramic and metal as a result of the distinctly different expansion coefficients. Special materials that expand upon heating are used as bed mats.

Nevertheless it is often observed in practice that the ceramic support body and/or the bed mat moves within the housing under the influence of pulsating exhaust gases. This is unsatisfactory. Therefore, attempts have been made to prevent these movements by means of terminal rings made of wire or sheet metal. Aside from the fact that these additional measures represent an additional expense, they have not been successful in practice.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a device so that movements of support bodies and/or bed mats relative to one another or to the housing can be reliably prevented.

Via elevations in accordance with an embodiment of the invention, the otherwise smooth jacket surface of the ceramic support body is modified to such an extent that a force-locking or form-locking connection takes place between the support body and the bed mat. In this way, relative movements of the two are prevented.

Advantageously, these elevations can include baked-on ceramic. These can either already be placed on a green blank or subsequently applied to a baked blank, preferably using stencils.

According to an embodiment of the invention, these elevations are annular. In particular, two parallel rings can be recommended, between which the bed mat is fixed immovably and protected from the pulsations.

According to an alternative embodiment, the elevations can be punctiform.

In this case it is advisable to incorporate into the bed mats recesses that correspond to the elevations. In this manner it is possible to prevent the support body and bed mat from performing any further relative movements with respect to one another.

To also rule out any relative movement between the housing and bed mat or support body, according to a further embodiment of the invention, the housing in turn may have recesses that correspond to the elevations on the support body.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

FIG. 1 illustrates a ceramic support body with annular elevations; and

FIG. 2 illustrates a support body with punctiform elevations.

DETAILED DESCRIPTION

FIG. 1 shows a first example embodiment. A ceramic support body 1 is recognizable, with a plurality of honeycomb-like channels, which for example are catalytically coated. On the jacket of the support body 1, a bed mat 2 is wound. To reliably prevent relative movement between the support body 1 and bed mat 2 from occurring, two annular elevations 3 are applied to the jacket of the support body 1. These have a heat-resistant material, especially baked-on ceramic, and fix the bed mat 2 in a form-locking way.

FIG. 2 shows an alternative exemplified embodiment. To the jacket surface of the ceramic bed mat 1, punctiform elevations made of ceramic are applied. The corresponding bed mat 2 has recesses 5, which correspond with the punctiform elevations 4. In this way, a form-locking connection is formed between the support body 1, elevations 4 and bed mat 2 or recesses 5, preventing relative movement.

To also prevent relative movement between the support body 1 and bed mat 2 on one hand, and the catalyst housing (not shown) on the other, the housing may be equipped in an area of its jacket with recesses that correspond to the elevations 3, 4. Catalyst housings with circumferential fins, which fit with the annular elevations 3 can be used without modification.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.

Claims

1. A device for aftertreatment of exhaust gases of internal combustion engines, the comprising:

an active ceramic support body;

a bed mat; and

a housing;

wherein a jacket of the support body has temperature-resistant elevations that are subsequently applied.

2. The device according to claim 1, wherein the elevations have a baked-on ceramic.

3. The device according to claim 1, wherein the elevations are annular.

4. The device according to claim 1, wherein the elevations are punctiform.

5. The device according to claim 4, wherein the bed mat has recesses that correspond with the elevations.

6. The device according to claim 1, wherein the housing has recesses that correspond with the elevations.

7. A device for treating exhaust gases of a vehicle, the device comprising:

a ceramic support body having a plurality of honeycomb-shaped channels formed therein;

a bed mat substantially circumscribing the ceramic support body; and

a plurality of engagement devices provided on the ceramic support body for fixedly supporting the bed mat to an outer surface of the ceramic support body, thereby preventing movement between the bed mat and the ceramic support body.

8. The device according to claim 7, wherein the engagement devices are punctiform elevations that are provided on the ceramic support body such that the punctifom elevations correspond to a plurality of apertures provided in the bed mat for fixedly supporting the bed mat.