WO2015094199A1

WO2015094199A1 - Exhaust catalyst body with non-destructive analysis element

Info

Publication number: WO2015094199A1
Application number: PCT/US2013/075897
Authority: WO
Inventors: William Robert Miller
Original assignee: Volvo Truck Corporation
Priority date: 2013-12-18
Filing date: 2013-12-18
Publication date: 2015-06-25

Abstract

An exhaust gas treatment catalyst assembly includes a capsule removably mounted in the assembly in an exhaust gas flow path in the assembly. The capsule includes a plug formed of the same or substantially the same material that makes up the filter or catalyst body. The plug experiences the same conditions as the catalyst body and provides a sample for analysis. The capsule may be removed and sent to a facility for analysis without the need to handle the whole catalyst assembly.

Description

Exhaust Catalyst Body with Non-Destructive Analysis Element Field of the Invention

The invention relates to exhaust gas treatment filters and catalysts having support bodies of ceramic, metallic or other solid structure material, and more particularly, to a removable element incorporated in an exhaust filter or catalyst that can be analyzed as a test sample of the filter or catalyst body.

Background and Summary

To meet regulations on emissions, vehicles with internal combustion engines use filters and catalysts to remove regulated emission products from the exhaust gas stream. For example, diesel engine- powered vehicles use particulate filters to remove particulate matter from the gas stream, oxidation catalysts to oxidize CO and vapor phase hydrocarbons, and selective reduction catalysts to convert NOx to nitrogen gas and water.

When the filter or catalyst performance is found to deteriorate or fail, the entire filter body or catalyst body must be removed from the vehicle and replaced. It is of interest to determine the cause of the deterioration or failure for warranty coverage, engineering design, engine or exhaust system diagnosis, and other reasons. For example, performance degradation may be caused by thermal damage, fuel poisoning, lubricant poisoning, coolant poisoning, poisoning from improper biofuel, or poisoning from improper SCR reactant or reductant. Analyzing the condition of a filter body or catalyst body is, however, time consuming and expensive, at least because in current practice the entire assembly is sent to a qualified facility for analysis.

The invention provides a solution. According to the invention, a filter assembly or catalyst assembly includes a capsule removably mounted in the filter assembly or catalyst in an exhaust gas flow path in the assembly. The capsule includes a removable plug formed to respond to degradation mechanisms in substantially the same way as the catalyst body. The capsule may be removed and sent to a facility for analysis.

According to the invention, the capsule plug is made of the same or substantially similar material as the filter body and catalyst coating. As used herein, "material" means one or both of the filter body material and the catalyst material, and "substantially similar material" means material that when exposed to the exhaust gas environment that the filter substrate and catalyst material are exposed to will experience changes sufficiently similar to those experienced by the filter material and/or catalyst material to be representative of the changes experienced by the filter material and/or catalyst material.

The capsule may be serialized, that is, carry a serial number that identifies it with the host filter or catalyst. Component suppliers typically apply serial numbers to catalyst housings to track manufacturing lot numbers of the filter bodies. This ensures that the analysis results are associated with the correct filter or catalyst and allows for creation of a database to track the filter body and capsule, and any replacement units, over the life of the vehicle.

The capsule may be formed as a hollow body open at both ends providing an interior space to support the plug. For convenient mounting and removal, the capsule may be formed as a cylindrical body having screw threads on an exterior surface and a head to allow the application of torque by a tool or by hand.

According to the invention, the capsule is mounted at or near the inlet face of the filter or catalyst body. According to one embodiment of the invention, the filter body or catalyst has a recess formed in the inlet face to accept the capsule. Alternatively, the capsule may be mounted on a receptacle provided in the housing near the inlet face of the filter or catalyst body. The receptacle may be carried on a frame spanning the inlet face of the filter or catalyst body, or may be fixed to an interior wall of the housing.

The recess in the filter or catalyst body or the frame includes means for securing the capsule against unwanted movement. If the capsule includes screw threads, the recess or frame receptacle is compatibly threaded. Other ways of securing the capsule may be used, for example, a bayonet mount or a detent arrangement.

Brief Description of the Drawings

The invention will be better understood by reference to the Detailed Description read in conjunction with the appended drawing figures, in which: Figure 1 is a side view of an embodiment of a test capsule according to the invention;

Figure 2 is a top view of the capsule of Figure 1;

Figure 3 is a section view of the capsule of Figures 1 and 2, taken along the line 3-3 in Figure 2;

Figure 4 is an end schematic view of an embodiment of a filter or catalyst assembly including a capsule according the invention; Figure 5 is a section view of the assembly of Figure 4 taken along the line 5-5;

Figure 6 is an end schematic view of an alternative embodiment of a filter or catalyst assembly including a capsule according the invention;

Figure 7 is a section view of the assembly of Figure 6 taken along the line 7-7; Figure 8 is an end schematic view of another alternative embodiment of a filter or catalyst assembly including a capsule according the invention;

Figure 9 is a section view of the assembly of Figure 8 taken along the line 9-9;

Figure 10 is an end schematic view of yet another embodiment of a filter or catalyst assembly including a capsule according the invention; and, Figure 11 is a section view of the assembly of Figure 10 taken along the line 11-11.

Detailed Description

The invention is directed to a test capsule removably mountable in an exhaust aftertreatment filter assembly or catalyst assembly. For the purposes of the following description, the term "catalyst body" will be used to refer to both the substrate and the catalyst material that may be coated or integrated into the substrate a filter. A catalyst body may be a diesel particulate filter (which is commonly catalyzed) or an oxidation catalyst, a selective reduction catalyst, or other similar device. The capsule includes a plug formed of the same or substantially the same material that makes up the catalyst body. The capsule is positioned in the catalyst assembly housing in the gas flow path so that capsule plug is exposed to and experiences the same conditions as does the catalyst body. The capsule may be conveniently removed and sent to a facility for analysis.

Figure 1 is a side view of an embodiment of a capsule 10 according to the invention. Figure 2 is a top view and Figure 3 is a section view taken along the line 3-3 in Figure 2. The capsule 10 according to the illustrated embodiment includes a hollow, cylindrical member 12 open at both an inlet end 14 and an outlet end 16 and defining a flow path therethrough. A plug 18 of catalyst body material is supported in an interior space defined by the hollow, cylindrical member 12.

According to the invention, the capsule plug 18 is made of the same or substantially similar material as one or both of the catalyst body and catalyst material. As used herein, "material" means one or both of the filter substrate and catalytic material, and "substantially similar material" means material that when exposed to the exhaust gas environment that the filter or catalyst is exposed to will experience changes sufficiently similar to those experienced by the filter material or catalyst material to be representative of the changes to the filter material or catalyst material.

The capsule may be serialized, that is, carry a serial number 20 that identifies it with the host filter or catalyst. This ensures that the analysis results are associated with the correct filter or catalyst. The embodiment of Figures 1-3 shows a cylindrical member 12, which for the convenience of mounting and removal, may have screw threads 22 on an exterior surface to secure the member 12 in an appropriately threaded frame member (as described below) and a head 24 to allow the application of torque by a tool or by hand.

Other mounting devices may be used in connection with the capsule member 12, for example, a bayonet mount, a spring clip, or a detent arrangement.

In addition, the capsule 10 may take other shapes capable of supporting a plug for exposure to an exhaust gas flow and suitable for mounting and removal in a catalyst assembly. For example, a square body using a spring clip or detent arrangement may be used.

According to the invention, the capsule 10 is mounted at or near an inlet face of the catalyst body. Figures 4 to 11 show some exemplary mounting arrangements for the capsule 10 in a catalyst assembly.

Figure 4 is an end view and Figure 5 is a longitudinal section of a schematically illustrated catalyst assembly 30 according to one arrangement. The catalyst assembly 30 includes a housing 32 that defines an exhaust gas flow path (a direction of flow indicated by the arrow 34). A catalyst body 40 is disposed in the housing 32 in the flow path. An inlet face 42 of the catalyst body 40 receives the incoming exhaust gas.

The catalyst body 40, as is known in the art, may be a body structure formed of ceramic, metallic, or other material. The body 40 is typically formed with a multiplicity of flow channels to provide a large contact area for exhaust gas. The body may be catalyzed by surface treatment or by impregnation of the material forming the body. Exhaust gas flowing through the flow channels comes into contact with the catalyst material to promote the desired reaction.

A capsule 10 is mounted in the housing 32 in the exhaust gas flow path. As shown in Figure 5, the capsule 10 may be mounted on an interior wall of the housing 32 at the inlet face 42 of the catalyst body 40. The capsule 10 is oriented to expose the plug 18 to the exhaust gas flow. A frame 50, in this embodiment an internally threaded sleeve is fixed to the wall of the housing 32 by appropriate means, for example, welding. Figures 6 and 7 show an arrangement similar to that of Figures 4 and 5, but with the capsule 10 mounted near the inlet face 42 of the catalyst body 40, but spaced therefrom. The sleeve 50 is fixed to the wall of the housing a distance from the surface of the inlet face 42 of the catalyst body 40. This arrangement may be more convenient for mounting or removing the capsule 10, depending on the structure of the housing 32. This arrangement may also be advantageous as the capsule 10 does not obstruct a portion of the catalyst body 40, allowing exhaust gas to flow in the space behind the capsule, but the capsule nonetheless receives a sufficient exhaust gas flow to serve as a sample of the catalyst body.

Figures 8 and 9 illustrate alternative arrangement for mounting the capsule 10 in the catalyst assembly 30. Figure 8 is an end view and Figure 9 is a longitudinal section view. According to this embodiment, the capsule 10 is supported by a frame including arms 52 fixed to the wall of the housing 32 and supporting the threaded sleeve 50. The arms 52 position the sleeve 50 and capsule 10 away from the wall, and as illustrated in this embodiment, centrally in the housing 32. The frame may be configured to position the sleeve 50 and capsule 10 at any particular location transversely spaced from the wall. In addition, the frame may position the sleeve 50 and capsule 10 longitudinally spaced from the inlet face 42, similar to the position shown in Figure 7.

According to another embodiment of the invention, shown in Figures 10 and 11, the catalyst body 40 has a recess 44 formed in the inlet face 42 to accept the capsule 10. The recess may be threaded, or a threaded sleeve may be fixed in the recess to accept the capsule 10 The invention has been described in terms of preferred principles and embodiments, which are intended to be illustrative but not necessarily limiting. Those skilled in the art will understand that substitutions may be made without departing from the scope of the appended claims.

Claims

1. An exhaust gas treatment assembly, comprising: a housing defining an exhaust gas flow path and having an inlet and an outlet; an exhaust gas treatment material body mounted in the housing in the exhaust gas flow path; and, a capsule removably mounted in the housing in the exhaust gas flow path, the capsule including a plug of material substantially the same as the exhaust gas treatment material.

2. The assembly of claim 1, wherein the capsule comprises a hollow member defining an interior space having an inlet and outlet, the plug being disposed in the interior space.

3. The assembly of claim 2, wherein the hollow member is cylindrical and includes screw threads formed on an outer surface thereof and comprising a frame member fixed in the housing to receive and support the capsule.

4. The assembly of claim 3, wherein the hollow member includes a head adapted for engagement with a tool.

5. The assembly of claim 1, comprising a frame fixed in the housing to receive and support the capsule.

6. A sample device for an exhaust gas treatment device having a specified catalyst material, comprising a plug of material substantially the same as a specified catalyst material and a capsule containing and supporting the plug, the capsule formed as a hollow, cylindrical body and being removably mountable in an exhaust gas treatment device assembly.

7. A method for providing an analysis sample of an exhaust gas treatment catalyst body, comprising the steps of: removably mounting a plug of catalyst body material in an exhaust gas treatment assembly in proximity to an inlet face of a catalyst body; simultaneously exposing the plug and the catalyst body to exhaust gas; and, removing the plug from the exhaust gas treatment assembly.