Catalyst unit, method for producing the same, and exhaust gas catalyst

Patent metadata

Field	Value
Publication number	US-10018094-B2
Application number	US-201515327953-A
Country	US
Kind code	B2
Filing date	Jun 11, 2015
Priority date	Jul 25, 2014
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A catalyst unit for an exhaust gas catalyst, having a ceramic catalyst body, and a metallic housing which encloses the catalyst body at least in some sections perpendicular to a gas throughflow direction. At least one bearing mat positioned between the catalyst body and the housing perpendicular to the throughflow direction. The catalyst body is retained in the housing via a force-closed press fit with the intermediate arrangement of the or each bearing mat such that, when seen in the throughflow direction of the catalyst body, the press fit between the housing and the catalyst body is formed exclusively at defined axial positions, the housing having groove-like depressions at the defined axial positions for reducing in some sections the inner cross-section of the housing, and the press fit between the housing and the catalyst body being formed exclusively in the region of the groove-like depressions.

First claim

The invention claimed is:

1. A catalyst unit for an exhaust gas catalytic converter, comprising:
a ceramic catalyst body through which exhaust gas flows;
a metallic housing, which seen perpendicularly to a through-flow direction of the ceramic catalyst body surrounds the ceramic catalyst body at least in some sections;
at least one bearing mat positioned between the ceramic catalyst body and the metallic housing viewed perpendicularly with respect to the through-flow direction of the ceramic catalyst body;
wherein the at least one bearing mat is held via a press fit in a force-fit manner in the metallic housing such that seen in the through-flow direction of the ceramic catalyst body the press fit between the metallic housing and the ceramic catalyst body is exclusively formed in defined axial positions,
wherein the metallic housing, in the defined axial positions, comprises groove-like recesses for reducing in some sections an inner cross section of the metallic housing and wherein the press fit between the metallic housing and the ceramic catalyst body is exclusively formed in a region of the groove-like recesses.

2. The catalyst unit according to claim 1 , wherein the at least one bearing mat is positioned between the ceramic catalyst body and the metallic housing exclusively in the region of the groove-like recesses of the metallic housing in through-flow direction of the ceramic catalyst body.

3. The catalyst unit according to claim 1 , wherein in through-flow direction of the ceramic catalyst body the metallic housing seen has a defined outer cross section between the groove-like recesses.

4. The catalyst unit according to claim 1 , wherein clearances are introduced into the metallic housing downstream of the first groove-like recess and upstream of a last groove-like recess seen in through-flow direction of the ceramic catalyst body.

5. The catalyst unit according to claim 1 , wherein bearing mats are inserted only in regions of the groove-like recesses.

6. An exhaust gas catalytic converter comprising
a plurality of catalyst units, each comprising:
a ceramic catalyst body through which exhaust gas flows;
a metallic housing, which seen perpendicularly to a through-flow direction of the ceramic catalyst body surrounds the ceramic catalyst body at least in some sections;
at least one bearing mat positioned between the ceramic catalyst body and the metallic housing viewed perpendicularly with respect to the through-flow direction of the ceramic catalyst body;
wherein the at least one bearing mat is held via a press fit in a force-fit manner in the metallic housing such that seen in through-flow direction of the ceramic catalyst body the press fit between the metallic housing and the ceramic catalyst body is exclusively formed in defined axial positions,
wherein the metallic housing, in the defined axial positions, comprises groove-like recesses for reducing in some sections an inner cross section of the metallic housing and wherein the press fit between the metallic housing and the ceramic catalyst body is exclusively formed in a region of the groove-like recesses.

7. A method for producing a catalyst unit having:
a ceramic catalyst body through which exhaust gas flows;
a metallic housing, which seen perpendicularly to a through-flow direction of the ceramic catalyst body surrounds the ceramic catalyst body at least in some sections;
at least one bearing mat positioned between the ceramic catalyst body and the metallic housing viewed perpendicularly with respect to the through-flow direction of the ceramic catalyst body;
wherein the at least one bearing mat is held via a press fit in a force-fit manner in the metallic housing such that seen in through-flow direction of the ceramic catalyst body the press fit between the metallic housing and the ceramic catalyst body is exclusively formed in defined axial positions,
wherein the metallic housing, in the defined axial positions, comprises groove-like recesses for reducing in some sections an inner cross section of the metallic housing and wherein the press fit between the metallic housing and the ceramic catalyst body is exclusively formed in a region of the groove-like recesses,
the method comprising:
a) providing the ceramic catalyst body;
b) providing the metallic housing;
c) providing the at least one bearing mat;
d) arranging the ceramic catalyst body and the at least one bearing mat in the metallic housing subject to forming the press fit between the metallic housing and the ceramic catalyst body.

8. The method according to claim 7 ,
wherein the metallic housing comprises groove-like recesses in defined axial positions,
wherein the inner cross section of the metallic housing in the region of the groove-like recesses is smaller than an outer cross section of the ceramic catalyst body surrounded by the at least one bearing mat in those axial positions in which the press fit between the metallic housing and the ceramic catalyst body is to be formed, so that when the ceramic catalyst body and the at least one bearing mat are arranged in the metallic housing the press fit between the metallic housing and the ceramic catalyst body automatically forms.

9. The method according to claim 7 ,
wherein the metallic housing comprises groove-like recesses in defined axial positions,
wherein the inner cross section of the metallic housing in the region of the groove-like recesses is larger than an outer cross section of the ceramic catalyst body surrounded by the at least one bearing mat in those axial positions in which the press fit between the metallic housing and the ceramic catalyst body is to be formed,
wherein after the arranging of the ceramic catalyst body and of the or each bearing mat in the metallic housing, the metallic housing in the region of the groove-like recesses is compressed in some sections and thus plastically deformed subject to forming the press fit between the metallic housing and the ceramic catalyst body.

10. The method according to claim 7 ,
wherein the metallic housing is provided without groove-like recesses,
wherein the inner cross section of the metallic housing is larger than an outer cross section of the ceramic catalyst body surrounded by the at least one bearing mat,
wherein following arrangement of the ceramic catalyst body and of the at least one bearing mat in the metallic housing, the metallic housing in some sections is compressed subject to forming the groove-like recesses and subject to forming the press fit between the metallic housing and the ceramic catalyst body.

11. The method according to claim 7 , wherein outer dimensions of the metallic housing in an inlet and outlet region is calibrated to a defined dimension.

12. The method according to claim 7 , wherein outer dimensions are defined by crimping or widening.

Assignees

• Man Diesel & Turbo Se

Inventors

• Döring Andreas

Classifications

• F01N2350/02

  Fitting ceramic monoliths in a metallic housing · CPC title

• F01N3/2828 Primary

  Ceramic multi-channel monoliths, e.g. honeycombs · CPC title

• F01N2450/02

  Fitting monolithic blocks into the housing · CPC title

• F01N2450/20

  by mechanical joints, e.g. by deforming housing, tube, baffle plate or parts thereof · CPC title

• F01N3/2853 Primary

  using mats or gaskets between catalyst body and housing · CPC title