US20160040582A1

US20160040582A1 - Remanufactured exhaust system component

Info

Publication number: US20160040582A1
Application number: US14/455,684
Authority: US
Inventors: Robert Eugene Sharp; Adam William Ostein; Bharat Kumar Meduru; Curtis John Graham
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2014-08-08
Filing date: 2014-08-08
Publication date: 2016-02-11

Abstract

An exhaust system component is disclosed. The exhaust system component may have a tubular body that defines a passage. The tubular body may have a joining portion that is configured to fluidly connect the passage to another exhaust system component. The joining portion may have a first layer of cast iron. The joining portion may also have a second layer covering at least a portion of the first layer. The second layer may contain at least iron, chromium, and aluminum.

Description

TECHNICAL FIELD

The present disclosure is directed to an exhaust system component, and more particularly, to a remanufactured exhaust system component.

BACKGROUND

Many engines produce harsh operating conditions that cause damage to various engine components and limit their useable lifetime. Engine exhaust systems, in particular, are exposed to the extreme heat of exhaust gases that exit the combustion chambers, causing wear and corrosion that erodes material until the exhaust system component fails. In one example, a cast iron exhaust manifold may erode at a joint between two manifold sections, eventually resulting in failure of the joint. Failure of a single component may render the entire engine unusable. While the engine may operate again if the component is replaced, total replacement of a component, such as an exhaust manifold, is cost-prohibitive. Therefore, it would be advantageous to reuse a worn exhaust manifold, if possible.
A current attempt to restore a worn exhaust manifold includes adding additional joint connection means to secure manifold sections together and/or cover worn sections to prevent further erosion. For example, a joining insert may be placed in or on an exhaust manifold to hold two or more components together and/or protect an eroded portion from further damage. While these inserts may temporarily extend the lifetime of the associated engine components, they are less than ideal. In particular, they are susceptible to damage themselves and do not provide sufficient strength and/or corrosion resistance to be a satisfactory long-term solution for reclaiming an exhaust system component.
The present disclosure is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.

SUMMARY

In one aspect, the present disclosure is directed to an exhaust system component. The exhaust system component may include a tubular body that defines a passage. The tubular body may include a joining portion that is configured to fluidly connect the passage to another exhaust system component. The joining portion may include a first layer of cast iron. The joining portion may also include a second layer covering at least a portion of the first layer. The second layer may contain at least iron, chromium, and aluminum.
In another aspect, the present disclosure is directed to a method of remanufacturing an exhaust system component. The exhaust system component may include a cast iron tubular body that defines a passage. The tubular body may include a joining portion that is configured to fluidly connect the passage to another exhaust system component. The method may include removing material from the joining portion. The method may also include depositing a coating material on the component at a location where the material was removed. The coating material may contain at least iron, chromium, and aluminum.
In yet another aspect, the present disclosure is directed to an exhaust manifold. The exhaust manifold may include a first manifold section. The first manifold section may define a first passage and include a first joining portion. The exhaust manifold may also include a second manifold section. The second manifold section may define a second passage and include a second joining portion. The first joining portion may he received within the second joining portion at a joint of the exhaust manifold. At least one of the first joining portion and the second joining portion may include a first layer of cast iron and a second layer covering at least a portion of the first layer. The second layer may contain at least iron, chromium, and aluminum.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of an exemplary power system;

FIG. 2 is an illustration of an exemplary exhaust manifold that may be used in conjunction with the power system of FIG. 1;

FIG. 3 is another illustration of the exhaust manifold of FIG. 2; and

FIG. 4 is an illustration of an exhaust component at various stages of a remanufacturing process.

DETAILED DESCRIPTION

FIG. 1 illustrates a power system 10. Power system 10 may include an engine 12 such as, for example, a diesel engine, a gasoline engine, a natural gas engine, or any other engine known in the art. In one embodiment, engine 12 may include a plurality of cylinders 14. For example, engine 12 may be a six-cylinder internal combustion engine. It should be understood, however, that engine 12 may include additional or fewer cylinders 14. Power system 10 may further include an air induction system 16 and an exhaust system 18.
Air induction system 16 may be configured to introduce compressed air into a combustion chamber 20 at least partially formed by a cylinder 14 of engine 12. Air induction system 16 may include a compressor 22 connected to engine 12 via an intake manifold 24. Compressor 22 may include a fixed geometry type compressor, a variable geometry type compressor, or any other type of compressor known in the art. It is contemplated that more than one compressor 22 may be included and disposed in parallel or in series relationship. It is further contemplated that compressor 22 may he omitted, for example, when a non-compressed air induction system is desired.
Exhaust system 18 may include a plurality of exhaust system components, including a turbine 26 and an exhaust manifold 28. In an exemplary embodiment, exhaust system 18 may he configured to direct exhaust from engine 12 to turbine 26 via exhaust manifold 28. Turbine 26 may be mechanically coupled to compressor 22 to drive compressor 22 in a manner known in the art. For example, as hot exhaust gases exiting engine 12 expand against blades (not shown) of turbine 26, turbine 26 may be caused to rotate, thereby rotating connected compressor 22. Exhaust manifold 28 may deliver exhaust gasses from combustion chambers 20 to turbine 26.
In an exemplary embodiment, exhaust manifold 28 may include a plurality of manifold sections 30 and an exhaust pipe 32. Manifold sections 30 may each include a main passage 34 and one or more communication ports 35 that exchange exhaust gas between a combustion chamber 20 and main passage 34. In an exemplary embodiment, manifold sections 30 may include a center section 36, and first and second side sections 38, 40. Center section 36 may be connected to first and second side sections 38, 40 at a pair of joints 42. Center section 36 may be connected to exhaust pipe 32 at a joint 44. In use, exhaust gas may be directed by communication ports 35 through one or more main passages 34, and into exhaust pipe 32 before reaching turbine 26.
FIG. 2 depicts manifold sections 30 of exhaust manifold 28 in more detail. In an exemplary embodiment, center section 36 may include a first open end 46 and a second open end 48. Center section 36 may further include at least one outlet 50 surrounded by an outlet flange 52. First side section 38 and second side section 40 may each include a closed end 54 and an open end 56. Center section 36, first side section 38, and second side section 40 may each further include a pair of communication ports 35 (shown only in FIG. 1) each surrounded by a port flange 58. Port flanges 56 may each include at least one bore 60 (shown only in FIG. 3) for receiving a fastener 62, such as a mounting bolt.
In use, center section 36, first side section 38, and second side section 40 may be joined together and secured to engine 12. As shown in FIG. 2, open ends 56 of first and second side sections 38, 40 may be joined to first and second open ends 46, 48 of center section 36 at joints 42. In an exemplary embodiment, joints 42 may include metal-on-metal joints in which a male connector of one manifold section 30 is inserted into a larger female connector of another manifold section 30. Each port flange 58 may be mounted to a portion of engine 12 (e.g., an engine block) via fasteners 62. Center section 36 may be mounted to exhaust pipe 32 via outlet flange 52.
FIG. 3 depicts center section 36 disconnected from first side section 38 and second side section 40. Center section 36 may include a first joining portion 64 at first open end 46 and a second joining portion 66 at second open end 48. First side section 38 may include a third joining portion 68 at open end 56 and second side section 40 may include a fourth joining portion 70 at open end 56. The joining portions 64, 66, 68, 70 may be portions of each respective manifold section 30 that are configured to fluidly connect a passage (e.g., main passage 34) to another exhaust system 18 component (e.g., another manifold section 30, a combustion chamber 20, exhaust pipe 32, etc.). In an exemplary embodiment, first joining portion 64 may be a female connector configured to receive third joining portion 68, which may be a male connector. Second joining portion 66 and fourth joining portion 70 may be similarly configured as female and male connectors, respectively. One or more of joining portions 64, 66, 68, and 70 may be separable from a remainder of a manifold section 30 or may be permenantly attached (e.g., integrally formed).
Each open end 46, 48, and 56 may define an opening 71 into a respective main passage 34. In an exemplary embodiment, manifold sections 30 may include tubular bodies that define main passages 34 and openings 71. The tubular bodies may have a thickness that defines an inner diameter and an outer diameter at each respective joining portion 64, 66, 68, 70. Each tubular body may be formed of a base material, such as cast iron. Other base materials are possible, however, such as steel. Other components of exhaust system 18 (e.g., exhaust pipe 32) may be similarly constructed out of a base material (e.g., cast iron, steel, or other material).
Joints 42, while depicted and described as male-female connection joints, may be any type of connection known in the art. Further, joints 42 may include additional components, such as collars, seals, bearings, washers, etc. For example, joints 42 may be slip-fit joints in which a collar connects adjacent manifold sections 30. In addition, it should be understood that the configuration of joints 42 may be reversed, e.g., first joining portion 64 may be a female connector configured to receive a male connector third joining portion 68 and/or second joining portion 66 may be a female connector configured to receive a male connector fourth joining portion 70.
In some embodiments, joints 42 may include one or more of joining portions 64, 66, 68, and 70 that are formed from a plurality of components that are removably or permenantly attached to one another. For example, a joint 42 may include a joining portion (not shown) that includes one or more cylindrical collars configured to be attached to a manifold section 30 and either receive a corresponding joining portion (e.g., a male joining portion of another manifold section 30) or be received by a corresponding joining portion (e.g., a female joining portion of another manifold section 30).
In addition, it should be understood that other configurations of exhaust manifold 28 are possible. For example, exhaust manifold 28 may include more or less manifold sections 30 with one or more connections to exhaust pipe 32. Further, exhaust system 18 may include one or more additional or alternative exhaust components besides those described herein, such as one or more housings, turbocharger components, exhaust valves, exhaust gas recirculation (ECR) components, etc.
In an exemplary embodiment, one or more components of exhaust system 18 may include at least a portion that has been used in a process to add a layer of coating material to a layer of base material of the component. For example, one or more components of exhaust system 18 may be used in a remanufacturing process to reclaim the component after it has been used and/or damaged. The remanufacturing process may include adding a coating material to the component. In one example, the coating material may be deposited on the component at a location where base material, such as corroded or otherwise damaged base material, was removed. The coating material may form a layer that is mechanically bonded to a layer of base material, such as an outer surface of base material or an inner surface of base material, depending on the exhaust system 18 component being remanufactured.
In an exemplary embodiment, exhaust manifold 28 may include one or more remanufactured components, which includes components in which at least a portion of the component has been remanufactured. For example, as shown in FIG. 3, first and second side sections 38, 40 may include remanufactured sections 72. Remanufactured sections 72 may correspond to at least a portion of third and fourth joining portions 68, 70. Remanufactured sections 72 may include a layer of coating material covering a layer of base material of first and second side sections 38, 40. In an exemplary embodiment, the coating material may be a metal alloy material. For example, the coating material may be a metal alloy material containing at least iron, chromium, and aluminum.
As shown in FIG. 3, each remanufactured section 72 may be located adjacent a base section 74, which have not been remanufactured. For example, remanufactured section 72 may extend from open end 56 to a material intersection 76 at which remanufacture section 72 meets base section 74. In an exemplary embodiment, material intersection 76 may be a location where an exposed surface of coating material in remanufactured section 72 is continuous with an exposed surface of base material in base section 74. The exposed surface may be an outer surface of the respective manifold section 30 or an inner surface of the respective manifold section 30, depending on the type of joining portion that is remanufactured (e.g., male or female connector).
An exemplary remanufacturing process for producing remanufactured sections 72 will be described in more detail below.

INDUSTRIAL APPLICABILITY

The disclosed remanufacturing process may be applicable to add a coating material to an engine component. The coating material may be configured to enhance various properties of the remanufactured component. For example, the coating material may provide additional strength and/or corrosion resistance. The remanufacturing process may also allow a used component to be reclaimed (i.e., reused) when it may otherwise require replacement, thereby lowering costs associated with repairing an engine.
The remanufacturing process may be particularly applicable to reclaim exhaust system components, such as joining portions of one or more manifold sections (including joining portions that can be. separated from a manifold section, such as a removable collar). During operation, an engine (e.g., engine 12) produces exhaust gases that travel through the components of an exhaust system (e.g., exhaust system 18). These gases are often extremely hot (e.g., 850° C.) and include chemical compositions that, together with the extreme heat, cause damage to exhaust system components over time. For example, the base material (e.g., cast iron) of one or more portions of an exhaust manifold (e.g., exhaust manifold 28) may corrode and/or wear down from exposure to the exhaust gases and associated heat. The exemplary disclosed remanufacturing process may be used to replace and/or supplement corroded, worn, damaged, and/or otherwise used base material and extend the life of the component.
Fig, 4 depicts an exemplary exhaust system component 78 at various stages of an exemplary remanufacturing process. In particular, FIG. 4 depicts exhaust system component 78 at a first stage 80, a second stage 82, a third stage 84, and a fourth stage 86 of the remanufacturing process, which may include step 81 to move from first stage 80 to second stage 82, step 83 to move from second stage 82 to third stage 84 and step 85 to move from third stage 84 to fourth stage 86. In an exemplary embodiment, exhaust system component 78 is a manifold section 30. FIG. 4 shows an axial view of a portion of manifold section 30 (e.g., looking into opening 71 of an open end 56 of one of first and second side sections 38, 40).
Before starting the remanufacturing process, an operator may determine that an engine component would benefit from being remanufactured. Although a component may be selected for any reason, in one example an operator may identify a corroded exhaust manifold, which may have failed or be at risk of failure. To identify such a component, exhaust manifold 28 (and/or other exhaust system 18 components) may be disassembled and the components thereof cleaned (e.g., with a salt bath). An operator or machine may inspect the cleaned components and identify any components for remanufacture.
At first stage 80, a manifold section 30 selected for remanufacture includes a thickness 88 defined between an inner diameter and an outer diameter of a tubular body. At first stage 80, thickness 88 is made up of base material 90. In an exemplary embodiment, base material 90 is cast iron. As shown in FIG. 4, base material 90 includes a corroded area 92. It should be understood that corroded area 92 may refer to any damaged, worn, or otherwise used area of base material 90.
In step 81 of the remanufacturing process, material may be removed from manifold section 30. For example, a dimension 94 of corroded area 92 may be removed, resulting in manifold section 30 at second stage 82. Dimension 94 of corroded area 92 may be removed in any manner known in the art, such through a machining process. In an exemplary embodiment, dimension 94 may be an amount of material determined based on several factors. For example, dimension 94 may be determined based on an extent of corrosion and a maximum amount of material that can be replaced. In one example, dimension 94 may be approximately 0.1-2.0 mm. Further, it should be understood that in some instances, dimension 94 may not be uniform (i.e., more material may be removed on one side where more corrosion is present).
After performance of step 81, second stage 82 may include a remaining portion of base material 90, minus at least a portion of corroded area 92. The remaining portion of base material 90 may include an outer surface 96. In an exemplary embodiment, outer surface 96 may include a surface roughness suitable for bonding to a coating material. For example, outer surface 96 may include a surface roughness of at least approximately 2 μm. In some instances, the process of removing dimension 94 of corroded area 92 may result in an outer surface 96 having an acceptable surface roughness. In other instances, however, an additional surface roughening step may be performed.
In step 83 of the remanufacturing process, a coating material 98 may be applied to outer surface 96, resulting in manifold section 30 at third stage 84. Coating material 98 may be deposited at the location where base material 90 was removed Coating material 98 may be applied in any of a variety of manners, which may depend on the composition of coating material 98. In an exemplary embodiment, coating material 98 may be deposited onto outer surface 96 of base material 90 via wire arc spraying. It should he understood, however, that alternative material application processes may be used, such as combustion wire spraying, combustion powder spraying, wire or powder high-velocity oxygen fuel (HVOF) spraying, or combustion flame spraying. The application process used to apply coating material 98 may include molten material being deposited on base material 90 and mechanically bonding thereto as the molten material hardens. In one embodiment, approximately 0.5-3.0 mm of coating material 98 may be added.
Coating material 98 may be a metal alloy material configured to provide strength and/or oxidation resistance to manifold section 30. In an exemplary embodiment, coating material 98 may be a metal alloy containing at least iron, chromium, and aluminum. In one example, the metal alloy may he comprised of approximately 65-80% iron, 15-30% chromium, and 3-6% aluminum. This material has been found to exhibit high strength and corrosion resistance, exhibiting little to no damage after endurance testing of a component remanufactured using the disclosed remanufacturing process. Other materials exhibited damage after the same testing.
In step 85, a dimension 100 of coating material 98 may be removed, resulting in manifold section 30 at fourth stage 86. Dimension 100 may be removed in any manner known in the art, such as a machining process. Dimension 100 may be selected such that a certain resulting thickness 102 of manifold section 30 may be produced. For example, dimension 100 may be approximately 0.1-1.0 mm. Thickness 102 may be selected based on a desired working thickness of manifold section 30. For example, thickness 102 may be approximately equal to thickness 88. In this way, manifold section 30 may be the same or approximately the same size as it was before being remanufactured, allowing manifold section 30 to be easily reassembled with the other components of exhaust manifold 28.
In some embodiments, a similar remanufacturing process may be performed on another portion of a manifold section 30. For example, an inner portion of first open end 46 and/or second open end 48 of center section 36 may be remanufactured in a similar manner. For instance, a dimension of a corroded area on an inner surface of center section 36 may be removed and replaced with coating material 98, which may be similarly applied by wire are spraying (or other application process) and trimmed to a working thickness. In this way, different configurations of remanufactured manifold sections 30 may be combined to produce a remanufactured exhaust manifold 28. For example, male connectors-only, female connectors-only, or both male and female connectors may be remanufactured to produce a remanufactured joint (e.g., joint 42).
It should also be understood that other components of exhaust system 18 may be remanufactured using the remanufacturing process described herein. For example, exhaust pipe 32 or another component (e.g., housing, valve, EGR component) not shown, may be remanufactured by replacing a base material with coating material 98 in a manner similar to the remanufacturing process described herein.
After one or more exhaust system 18 components (e.g., manifold sections 30) are remanufactured, exhaust manifold 28 may be reassembled. For example, first joining portion 64 may receive third joining portion 68 and second joining portion 66 may receive fourth joining portion 70, and the remainder of exhaust system 18 components may he assembled and mounted to engine 12.
The exemplary disclosed remanufacturing process may allow a used engine component, such as an exhaust manifold section, to be reclaimed by replacing old and possibly corroded, damaged, and/or worn base material with a coating material. The coating material may be applied through a process (e.g., wire are spraying) that mechanically bonds the coating material to a remainder of the base material, allowing the coating material to be retained on the base material and machined to working dimensions. In addition, the coating material may be a metal alloy containing at least iron, chromium, and aluminum, as this material has been found to exhibit properties that provide strength and oxidation resistance, which are beneficial for exhaust system components. Further, the remanufacturing process disclosed herein extends the lifetime of an engine component, thereby reducing costs by avoiding replacement of the entire component.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed remanufactured components and remanufacturing process. For example, the exemplary disclosed remanufacturing process and remanufactured components are not limited to used components and may be implemented as a new (e.g., unused) component and/or in a process for manufacturing the new component. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed embodiments. It is intended. that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.

Claims

What is claimed is:

1. An exhaust system component, comprising:

a tubular body defining a passage and including a joining portion configured to fluidly connect the passage to another exhaust system component,

wherein the joining portion includes:

a first layer of cast iron; and

a second layer covering at least a portion of the first layer and containing at least iron, chromium, and aluminum.

2. The exhaust system component of claim 1, wherein the joining portion defines an open end of the tubular body.

3. The exhaust system component of claim 2, wherein the joining portion extends from the open end to a material intersection, the material intersection being a location where an exposed surface of the second layer is continuous with an exposed surface of the first layer.

4. The exhaust system component of claim 1, wherein the second layer is mechanically bonded to an outer surface of the first layer.

5. The exhaust system component of claim 1, wherein the second layer is mechanically bonded to an inner surface of the first layer.

6. The exhaust system component of claim 1, wherein the second layer contains approximately 65-80% iron, 15-30% chromium, and 3-6% aluminum.

7. The exhaust system component of claim 1, wherein the second layer has a thickness of approximately 0.1-2.0 mm.

8. The exhaust system component of claim 1, wherein the tubular body is configured to be mounted to an engine and the passage is configured to receive exhaust gas from a combustion chamber of the engine.

9. A method of remanufacturing an exhaust system component having a cast iron tubular body that defines a passage and includes a joining portion configured to fluidly connect the passage to another exhaust system component, the method comprising:

removing material from the joining portion; and

depositing a coating material on the component at a location where the material was removed,

wherein the coating material contains at least iron, chromium, and aluminum.

10. The method of claim 9, wherein the coating material is deposited using a wire arc spray process.

11 The method of claim 9, wherein removing the material from the joining portion includes removing the material from an outer surface of the tubular body.

12. The method of claim 9, wherein removing the material from the joining portion includes removing the material from an inner surface of the tubular body.

13. The method of claim 9, further including removing a portion of the coating material to achieve a working thickness of the tubular body.

14. The method of claim 9, wherein the exhaust component is a section of an exhaust manifold and the method further comprises disassembling the exhaust manifold before removing the material and reassembling the exhaust manifold after depositing the coating material.

15. The method of claim 14, Wherein reassembling the exhaust manifold includes inserting the joining portion into a portion of another section of the exhaust manifold or receiving a portion of another section of the exhaust manifold in the joining portion.

16. The method of claim 9, wherein the coating material contains approximately 65-80% iron, 15-30% chromium, and 3-6% aluminum.

17. The method of claim 9, wherein removing the material includes removing approximately 0.1-2.0 mm of cast iron material from a thickness of the tubular body and depositing the coating material includes adding approximately 0.5-3.0 mm of coating material to a thickness of the tubular body.

18. An exhaust manifold, comprising:

a first manifold section defining a first passage and including a first joining portion; and

a second manifold section defining a second passage and including a second joining portion,

wherein the first joining portion is received within the second joining portion at a joint of the exhaust manifold, and

wherein at least one of the first joining portion and the second joining portion includes:

a first layer of cast iron; and

19. The exhaust manifold of claim 18, wherein only one of the first joining portion and the second joining portion include the second layer.

20. The exhaust manifold of claim 18, wherein both of the first joining portion and the second joining portion include the second layer.