GB2558248A

GB2558248A - End-cap assembly for an after treatment system

Info

Publication number: GB2558248A
Application number: GB1622078.2A
Authority: GB
Inventors: A Niaz Naseer
Original assignee: Perkins Engines Co Ltd
Current assignee: Perkins Engines Co Ltd
Priority date: 2016-12-23
Filing date: 2016-12-23
Publication date: 2018-07-11
Anticipated expiration: 2036-12-23
Also published as: GB2558248B; GB201622078D0

Abstract

A lightweight/compact end-cap, for an exhaust gas after-treatment system, to provide a connection between an engine or an engines exhaust and an exhaust gas treatment canister. The end-cap 60 includes a cylindrical outer wall 63 and an end wall 66; an inlet/out pipe 69 which passes through the outer wall 63, eg across the entire diameter of the end-cap, and may have openings 68A; and a bracket 70 that holds the pipe 69 in the end-cap and stabilizes the inlet/outlet pipe 69 to prevent failures caused by large vibrational forces caused by the flow of the exhaust gas through the end-cap 60. The bracket 70 encircles the inlet/outlet pipe 69 and has at least three contact surfaces, eg in the form of fold tabs; one with the end wall 66 of the end-cap and two with the outer wall 63 of the end cap. The gauge of the pipe 69 may be less than 3mm; the gauge of the bracket 70 may be less than 2mm.

Description

(56) Documents Cited:

WO 2013/160633 A1 US 20090232592 A1 (71) Applicant(s):

Perkins Engines Company Limited (Incorporated in the United Kingdom)

Frank Perkins Way, Eastfield, PETERBOROUGH, PE1 5FQ, United Kingdom (58) Field of Search:

INT CL F01N, F16L

Other: EPODOC, WPI, Patent Fulltext (72) Inventor(s):

Naseer A Niaz (74) Agent and/or Address for Service:

Anand Varu

Caterpillar (UK) Limited, Eastfield, PETERBOROUGH, Cambridgeshire, PE1 5FQ, United Kingdom (54) Title of the Invention: End-cap assembly for an after treatment system

Abstract Title: End-cap assembly for an exhaust gas after-treatment system (57) A lightweight/compact end-cap, for an exhaust gas after-treatment system, to provide a connection between an engine or an engine’s exhaust and an exhaust gas treatment canister. The end-cap 60 includes a cylindrical outer wall 63 and an end wall 66; an inlet/out pipe 69 which passes through the outer wall 63, eg across the entire diameter of the end-cap, and may have openings 68A; and a bracket 70 that holds the pipe 69 in the end-cap and stabilizes the inlet/outlet pipe 69 to prevent failures caused by large vibrational forces caused by the flow of the exhaust gas through the end-cap 60. The bracket 70 encircles the inlet/outlet pipe 69 and has at least three contact surfaces, eg in the form of fold tabs; one with the end wall 66 of the end-cap and two with the outer wall 63 of the end cap. The gauge of the pipe 69 may be less than 3mm; the gauge of the bracket 70 may be less than 2mm.

68B

FIG. 2

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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FIG.1

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FIG. 2

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FIG.4B

FIG.4A

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FIG.4C

END-CAP ASSEMBLY FOR AN AFTER TREATMENT SYSTEM

TECHNICAL FIELD

This disclosure relates to after treatment systems of the type comprising a canister 5 containing exhaust gas treatment systems, and in particular an end-cap assembly for flowing exhaust gas into or out of such after treatment systems.

BACKGROUND

Engines, such as internal combustion engines, exhaust a complex mixture comprising air pollutants and condensate. In order to comply with environmental and legal requirements and sometimes in order to improve performance of the engine, a combustion exhaust gas after treatment assembly may be provided, connected to exhaust ports of the engine, for treating the exhaust gasses.

An exhaust gas treatment assembly typically comprises one or more gas permeable blocks of ceramic or mineral material, which are clamped in a housing, typically cylindrical and often referred to as a can or canister. The housing defines a flowpath with inlet and outlet connections via which exhaust gas is directed to flow through the block or blocks. Each block may act as a filter, for example, if the assembly is to function as a diesel particulate filter (DPF), or may comprise a catalyst, for example, if the assembly is to function as a diesel oxidation catalyst (DOC) or selective catalytic reductor (SCR). The blocks may be formed with numerous parallel channels separated by thin walls and opening alternately at either end of the block or otherwise as known in the art to allow gas to flow through the block from one axial end to the other.

The inlet and outlet connections to the housing, for flowing exhaust gas into or out of the housing may comprise flow hoods and/or end caps. A flow hood may comprise a pipe through which exhaust gas from the engine can flow coupled with to an opening in a hood so that gas flows through the pipe and into the hood and then into the after treatment canister. A flow hood may also be used for an outlet of the after treatment canister so that the treated exhaust gas flows into the hood and out through an opening in the hood into a pipe that is coupled with the exhaust pipe. In general, the pipes for the flow hood may

-1have a thickness gauge greater than about 5-10 millimeters or so and be coupled directly to the hood/end-cap. The exhaust gases may travel through the pipes at high velocity causing strong vibrations in the inlet/outlet pipes and especially the connection between the pipes and the hood/end-cap.

Due to increased attention for the environment exhaust emission standards have become and still are becoming more stringent. Moreover, due to increase of fuel costs engine performance and economics have become more important. In order to comply with these requirements engine manufacturers have developed combustion exhaust after treatment assembly that are tailored to specific engines, depending on e.g. engine type, size, class and intended use of the engines, fuel types and engine loads. This has led to a large variety of types of combustion exhaust after treatment components, as well as sizes, shapes and dimensions, which may lead to an increase of costs in e.g. manufacturing and stock.

Moreover exhaust treatment assemblies may be large and normally have to be assembled from many different components, placed in different positions of a vehicle or work tool, separated by connecting pipes and hoses. Additionally, the overall axial length of the housing must be sufficient to accommodate the after treatment system as well as the mounting interface and inlet and outlet connections, which in turn imposes dimensional constraints on adjacent components of a vehicle or other machine on which the assembly will be used.

In order to use an after treatment system with a compact engine or to reduce the mass of the after treatment system, the components of the after treatment system must be reduced in size/weight. This means that the pipes flowing the gas into and out of the after treatment system must have a small thickness/gauge so that the pipes can fit into the compact engine and/or reduce the mass of the after treatment system. However, use of small thickness/gauge pipes in the flow hood reduces the strength the pipes and in particular the strength of the connection between the pipes and the end cap and can result in the pipe breaking away from the end-cap when the exhaust gas causes the pipe to vibrate.

The disclosed embodiments in this description are directed to addressing at least one of the issues as set out above.

-2SUMMARY OF THE DISCLOSURE

An end-cap for an exhaust gas after treatment system, and, more particularly, but not by way of limitation, a lightweight/compact end-cap. The end-cap comprises a housing having a circumferential outer-wall defining a cylinder having a first opening at one end and a second opening at a second end of the cylinder and an end-wall covering and closing the first opening. The second opening of the end-cap housing is configured to couple the end-cap housing with an exhaust gas treatment canister and provide fluid communication between the end-cap housing and the exhaust gas treatment canister. An inlet/outlet passes through the circumferential outer-wall and includes a first end disposed within the end-cap housing and configured in use to provide for exhaust gas to flow through the conduit into or out of the end-cap housing, wherein the conduit is arranged to be perpendicular to a longitudinal axis of the cylinder defined by the circumferential outerwall. A bracket is coupled with the inlet/outlet pipe, the end-wall and the outer-wall and comprising a substrate defining an opening for encircling a section of the conduit and having at least three contact surfaces and configured in use to support the conduit in the end-cap housing, wherein a first of the at least three contact surfaces contacts the end-wall and a second and a third of the at least three contact surfaces contact the outer-wall.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is described in conjunction with the appended figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

Fig. 1 shows an existing engine exhaust after treatment assembly for coupling with an engine;

FIG. 2 illustrates an end cap assembly in accordance with some embodiments of the present disclosure;

FIG. 3 illustrates a mounting bracket for securing an inlet/outlet conduit for communicating exhaust gas into or out of an after treatment system; and

FIGs. 4A, 4B and 4B illustrate a coupling arrangement for coupling the mounting bracket of Fig. 3 to an end-cap gap housing.

-3In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

DETAILED DESCRIPTION

In the description the same or similar elements and features have the same or corresponding reference signs. The embodiments shown and discussed are only disclosed by way of example and should not be construed as limiting the disclosure. The disclosure will be elucidated in relation to an internal combustion engine, in particular but not limited to a diesel engine. It should be understood that an assembly according to the disclosure could also be used with other types of engines, such as but not limited to gasoline, natural gas, bio fuel or liquefied gas engines.

Throughout the description different parts of an engine exhaust after treatment system may be referred to by abbreviations, wherein SCR will be used for Selective Catalytic Reductor or Reduction or catalyst, PF will be used for Particle Filter or Filtering, DPF for Diesel Particle Filter or Filtering, LNT for Lean NOx Trap and DOC for Diesel Oxidation Catalyst. Throughout the description reference will be made to an exhaust after treatment system, which may also be referred to as an after treatment assembly.

For combustion engines, for example internal combustion engines such as but not limited to diesel engines an exhaust system is generally provided for expelling exhaust gasses to the environment. It is common practice to provide at least an exhaust gas after treatment system or assembly between the engine exhaust ports of the engine block and the end of the exhaust pipe such as the tail pipe. The exhaust gas after treatment system may be used for e.g. environmental reasons, for engine performance reasons and/or for fuel economical reasons and may be provided with different components, depending on for example engine size, fuel type, environmental requirements, fuel economical requirements, engine performance requirements and other engine or control requirements or requirements of e.g. a work tool, vehicle or appliance in or for which the engine is to be used. These components may e.g. be chosen from the group including mufflers, a heat sources for PF regeneration, catalysts and a mixing chambers and other exhaust gas treatment devices.

-4Figure 1 illustrates a common exhaust after treatment assembly 10 including a mount 12 for mounting a first after treatment canister 14 and a second after treatment canister 16 to an engine (not shown). The second after treatment canister 16 may be coupled with a first bracket 24 and a second bracket 26, spaced apart, for holding the second after treatment canister 16 in position on the engine.

In Fig. 1, a number of connectors 52 may be used to fix the first and the second after treatment canisters 14 and 16 to the mount 12. The mount 12 may be configured to be lifted in two directions FI, F2, where the directions FI, F2 may include a substantially perpendicular angle. The mount 12 may include foot elements 30 may have foot surfaces, which define a substantially flat plane W for mounting the system to the engine.

As is shown in Fig. 1, first exhaust gas after treatment component 14 may be mounted in the first mounting position and a second exhaust gas after treatment system component 16 may be mounted in the second mounting position 20 and a third exhaust gas after treatment system component 122 may be mounted in a third mounting position. The first, second and third exhaust gas after treatment system components 14, 16 and 22 may be comprise from the group including a particle filter PF, a muffler, a heat source for PF regeneration, a Selective Catalytic Reductor (SCR), a DOC, a LNT, and a mixing chamber and combinations of two or more of these components.

In operation, exhaust gas flow (g) is into an inlet 6 into the first exhaust gas after treatment component 14, through the first, second and third exhaust gas after treatment system components 14, 16 and 22 and out through an outlet 9 in the second exhaust gas after treatment component 16.

As can be seen from Fig. 1, after treatment systems and after treatment mounting systems may comprise complex, large and/or heavy systems. At the same time, for cost and efficiency reasons, engines are being designed that are less complex, smaller, and/or lighter. To meet these goals, it may be desirable that components of the after treatment system be less complex, smaller, and/or lighter. However, in after treatment systems using smaller gauge pipes/conduits linking the after treatment canisters, the engine outlet and/or the exhaust, the forces associated with the vibrations in the system may cause the pipes/conduits to deform and/or disconnect. For example, inlet pipe connection point 50 and outlet pipe connection point 53 of the after treatment systems 10 are locations where vibrational forces will cause a failure if the inlet and/or outlet pipes (not shown) have a small gauge. The small gauge of the pipes may reduce the size/weight of the after

-5treatment system. For example, if the gauge of the inlet/outlet pipes is less than about 5 millimeters, the regular connection, inlet pipe connection point 50 and outlet pipe connection point 53, will fail under regular/repeated operation.

Figure 2 illustrates an end-cap 60, in accordance with some embodiments of the present disclosure, comprising a sidewall 63 and an end-wall 66. The sidewall 63 describes a circumferential cylindrical shape that can be coupled with an after treatment canister (not shown). An inlet/outlet pipe 66 extends into an interior space in the end-cap 60. The inlet/outlet pipe 66 is couple to the end-cap 60 by a mounting bracket 70. The inlet/outlet pipe 66 comprises a coupling section 67 for coupling to pipes/conduits from an engine or to an exhaust pipe or the like.

The mounting bracket 70 is coupled by at least two attachment surfaces to the sidewall 63 and by at least one attachment surface to the end-wall 66. The inlet/outlet pipe 66 passes through an opening through the mounting bracket 70. In some embodiments the inlet/outlet pipe 66 may extend across the entire diameter of the sidewall 63 and may in some embodiments be attached to the sidewall 66 at a location farthest from an opening in the sideway 63 through which the inlet/outlet pipe 66 enters the end-cap 60. In some embodiments, the attachment of the mounting bracket 70 to the sidewall 63 and/or the end-wall 66 may comprise welds.

In use, the inlet/outlet pipe 66 supported in the end-cap 60 by the mounting bracket 70 provides that the inlet/outlet pipe 66 and/or coupling section 67 are stable and can withstand vibrational forces as exhaust gases pass through the after treatment system through pipework connected to the inlet/outlet pipe 66. In tests, it was found that the inlet/outlet pipe 66 and/or the coupling section when coupled to a pipe from the engine or to an exhaust system remained stable and/or did not fail under repeated operation even when the gauge of the inlet/outlet pipe 66 and/or the pipe from the engine or to an exhaust system was less than 2 millimeters. Preferably, in embodiments of the present disclosure the inlet/outlet pipe 66 is 1.5 millimeters or 1.0 millimeters, which greatly reduces the space needed for the inlet/outlet pipe 66 and or the space for coupling the inlet/outlet pipe 66 to the after treatment system.

In some embodiments, the inlet/outlet pipe 66 may comprise one or more openings 68A through which exhaust gas may flow. Arrangements of a plurality of the openings 68A along the inlet/outlet pipe 66 may provide for a controlled flow of the exhaust gas over a volume of the after treatment canister. This may provide for good interaction between the

-6flowing exhaust gas and the after treatment components deployed in the canister, such as injections of chemicals into the canister, catalysts deployed in the canister and/or the like. In some embodiments, openings in the mounting bracket 70 or openings 68B formed between the mounting bracket 70 and the end-cap housing may also provide for a more distributed/uniform flow of exhaust gas through the after treatment canister.

Figure 2 illustrates the end bracket 70 of the present disclosure. The end bracket 70 comprises a pipe support 73 through which the inlet/outlet pipe 66 is disposed. The inlet/outlet pipe 66 may be welded to a perimeter of the pipe support 73 or may be configured to fit securely within the pipe support 73.

The mounting bracket 70 may comprise attachment surfaces 73 for attaching to the endcap housing. The attachment surfaces 73 my comprise edges of the end bracket 70. In some embodiments, as illustrated in Fig. 2, one or more of the attachment surfaces 73 may comprise folded edges of the end bracket 70. These folded edges may provide a surface for engaging with an inner surface of the end-cap housing. For example, the folded edge of the mounting bracket may be welded to an interior surface of the end-cap housing.

Figures 4A, 4B and 4C illustrate embodiments of the end cap housing including slots through which the attachment surface 73 may be introduced to provide for connecting the mounting bracket 70 to the end cap housing. Where the attachment surface 73 comprises a folded edge, the folded edge may be slotted through the slots, as shown in the Figs. 4AC, so that the attachment surface 73 may be coupled with an outer surface of the end-cap housing. Such a configuration strengthens the coupling to forced acting normal or having component normal to the interior surface of the end cap housing.

In embodiments of the present disclosure, the thickness of the mounting bracket 70 is less than 2 millimeters and preferably 1.5 millimeters or 1.0 millimeters. Even with such a small thickness and with an inlet/outlet pipe having a gauge of under 5 millimeters and even less than 2 or 3 millimeters, the end-cap system prevents failure of the inlet/outlet pipe 66 and/or the coupling section 67 under repeated flow of exhaust gas through the after treatment system. As such, the end cap system is able to provide a lightweight/compact system that can withstand vibrations caused by the flow of exhaust gas through the after treatment system. Additionally, the end-cap system provides for uniform/dispersed gas flow through the after treatment canister.

-7In some embodiments, the mounting bracket 70 may be disposed substantially mid way down the end-wall 66. In other embodiments, the mounting bracket 70 may be positioned either side of the mid-point of the end wall. Where the inlet/outlet pipe 66 inlet/outlet pipe 66 extends less than mid-way into the end-cap, such as for an end-cap configured as an outlet for the after treatment canister, the mounting bracket 70 may have a curved shape.

INDUSTRIAL APPLICATION

The end-cap of the present disclosure provides for coupling an after treatment canister to an exhaust system of an engine where the end-cap provides for fluid communication between the engine exhaust system and the after treatment canister and provides a connection between the engine exhaust system and the after treatment canister that is capable of withstanding the vibrational forces produced by the flow of exhaust gases therethrough.

Claims

What is claimed is:

1. An end-cap for an exhaust gas treatment canister, comprising:

an end-cap housing comprising a circumferential outer-wall defining a cylinder having a first opening at one end and a second opening at a second end of the cylinder and an end-wall covering and closing the first opening, wherein the second opening is configured to couple the end-cap housing with the exhaust gas treatment canister and provide fluid communication between the end-cap housing and the exhaust gas treatment canister;

a conduit passing through the circumferential outer-wall having a first end disposed within the end-cap housing and configured in use to provide for exhaust gas to flow through the conduit into or out of the end-cap housing, wherein the conduit is arranged perpendicular to a longitudinal axis of the cylinder defined by the circumferential outer-wall; and a bracket coupled with the conduit, the end-wall and the outer-wall and comprising a substrate defining an opening for encircling a section of the conduit and having at least three contact surfaces and configured in use to support the conduit in the end-cap housing, wherein a first of the at least three contact surfaces contacts the end-wall and a second and a third of the at least three contact surfaces contact the outer-wall.
2. The end-cap of claim 1, wherein a gauge of the conduit is less than 3 millimeters.
3. The end-cap of claim 1 or 2, wherein the bracket is welded to at least a one of the end-wall and the outer-wall.
4. The end-cap in accordance with any of the preceding claims, wherein the bracket is welded to the conduit.
5. The end-cap in accordance with any of the preceding claims, wherein at least one of the contact surfaces comprises a fold tab.

-96. The end-cap in accordance with claim 5, wherein the at least one fold tab extends through a slot in one of the end-wall or the outer-wall.

5 7. The end-cap in accordance with any of the preceding claims, wherein the bracket is disposed at a mid-point of the cylinder.

8. The end-cap in accordance with any of the preceding claims, wherein the conduit extends diametrically across the cylinder.

9. The end-cap in accordance with claim 8, wherein the first end of the conduit is welded to the circumferential outer-wall.

10. The end-cap in accordance with any of the preceding claims wherein the conduit 15 includes one or more openings in a wall of the conduit configured to provide for a flow of gas through the wall of the conduit into or out of the end-can section.

11. The end-cap in accordance with any of the preceding claims, wherein the substrate either includes perforations or the substrate is configured to define openings between the

20 substrate and the end-cap housing to allow for a flow of exhaust gas through the perforations or openings.

12. The end-cap in accordance with any of the preceding claims, wherein the substrate comprises a flat substrate.

13. The end-cap in accordance with any of claims 1-11, wherein the substrate comprises a curved substrate.

-1014. The end-cap in accordance with any of the preceding claims wherein the conduits comprises one of an inlet pipe and an outlet pipe.

15. The end-cap in accordance with any of the preceding claims wherein the substrate 5 comprises a metal substrate that is less than 2 millimeters thick.

-1112

Amendment to the claims have been filed as follows

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What is claimed is:

1. An end-cap for an exhaust gas treatment canister, comprising:

an end-cap housing comprising a circumferential outer-wall defining a cylinder 5 having a first opening at one end and a second opening at a second end of the cylinder and an end-wall covering and closing the first opening, wherein the second opening is configured to couple the end-cap housing with the exhaust gas treatment canister and provide fluid communication between the end-cap housing and the exhaust gas treatment canister;

10 a conduit passing through the circumferential outer-wall having a first end disposed within the end-cap housing and configured in use to provide for exhaust gas to flow through the conduit into or out of the end-cap housing, wherein the conduit is arranged perpendicular to a longitudinal axis of the cylinder defined by the circumferential outer-wall; and

15 a bracket coupled with the conduit, the end-wall and the outer-wall and comprising a substrate defining an opening for encircling a section of the conduit and having at least three contact surfaces and configured in use to support the conduit in the end-cap housing, wherein a first of the at least three contact surfaces contacts the end-wall and a second and a third of the at least three contact surfaces contact the outer-wall.

2. The end-cap of claim 1, wherein a gauge of the conduit is less than 3 millimeters.

3. The end-cap of claim 1 or 2, wherein the bracket is welded to at least a one of the end-wall and the outer-wall.

4. The end-cap in accordance with any of the preceding claims, wherein the bracket is welded to the conduit.

5. The end-cap in accordance with any of the preceding claims, wherein at least one

30 of the contact surfaces comprises a fold tab.
6. The end-cap in accordance with claim 5, wherein the at least one fold tab extends through a slot in one of the end-wall or the outer-wall.

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5
7. The end-cap in accordance with any of the preceding claims, wherein the bracket is disposed at a mid-point of the cylinder.
8. The end-cap in accordance with any of the preceding claims, wherein the conduit extends diametrically across the cylinder.
9. The end-cap in accordance with claim 8, wherein the first end of the conduit is welded to the circumferential outer-wall.
10. The end-cap in accordance with any of the preceding claims wherein the conduit 15 includes one or more openings in a wall of the conduit configured to provide for a flow of gas through the wall of the conduit into or out of the end-can section.
11. The end-cap in accordance with any of the preceding claims, wherein the substrate either includes perforations or the substrate is configured to define openings between the

20 substrate and the end-cap housing to allow for a flow of exhaust gas through the perforations or openings.
12. The end-cap in accordance with any of the preceding claims, wherein the substrate comprises a flat substrate.
13. The end-cap in accordance with any of claims 1-11, wherein the substrate comprises a curved substrate.
14. The end-cap in accordance with any of the preceding claims wherein the conduits comprises one of an inlet pipe and an outlet pipe.
15. The end-cap in accordance with any of the preceding claims wherein the substrate 5 comprises a metal substrate that is less than 2 millimeters thick.

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Intellectual

Property

Office

Application No: GB1622078.2 Examiner: John Twin