exhaust pipe
By designing a specific internal and external curved section and a concave structure for the exhaust pipe, the problem of uneven mixing of the reducing agent in the exhaust flow was solved, achieving uniform dispersion and preventing overheating of the injector, thus improving the emissions and performance of the exhaust aftertreatment system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CATERPILLAR INC
- Filing Date
- 2021-11-09
- Publication Date
- 2026-07-24
AI Technical Summary
In existing exhaust aftertreatment systems, the reducing agent is unevenly mixed in the exhaust flow, leading to excessive emissions or ammonia leakage. Furthermore, the reducing agent injector is prone to overheating, and crystallized deposits obstruct flow and damage the system.
Design an exhaust pipe including specific inner and outer curved sections and a notch structure to ensure uniform dispersion of the reducing agent injector. The design of the inner and outer curved sections and the notch structure prevents the reducing agent from depositing and the injector from overheating, ensuring uniform mixing of the exhaust flow.
It achieves uniform dispersion of the reducing agent in the exhaust flow, reduces excessive emissions and ammonia leakage, prevents system blockage and injector overheating, and improves the efficiency and reliability of the exhaust aftertreatment system.
Smart Images
Figure CN116648554B_ABST
Abstract
Description
Technical Field
[0001] This disclosure generally relates to a pipe, and for example to an exhaust pipe for promoting uniform dispersion of a reducing agent in an exhaust stream. Background Technology
[0002] In the exhaust aftertreatment system, a reducing agent injector introduces a reducing agent (such as urea solution, anhydrous ammonia, or ammonia water) into the exhaust pipe, which guides the exhaust flow from the engine to the selective catalytic reduction (SCR) module. Once the exhaust flow enters the SCR module, the reducing agent selectively reacts with nitrous oxide (NOx) in the exhaust flow to convert NOx into other compounds that meet emission standards, such as nitrogen oxides (N2), water (H2O), and carbon dioxide (CO2).
[0003] However, once the reducing agent is introduced into the exhaust stream, it tends to settle onto the surface of the exhaust duct and, over time, may form crystalline deposits (e.g., urea, biuret, and / or cyanuric acid). These crystalline deposits obstruct the flow of the exhaust stream and / or damage the system. Additionally, the reducing agent introduced by the reducing injector tends to mix unevenly with the exhaust stream, which can lead to unwanted compounds passing through the SCR module. For example, the exhaust aftertreatment system may emit excessive nitrous oxide and thus fail to meet emission standards because the exhaust stream contains too little reducing agent in some sections. As a further example, the exhaust aftertreatment system may emit unreacted ammonia (NH3) due to excessive reducing agent in other sections of the exhaust stream, commonly referred to as ammonia leakage. Furthermore, because the reducing agent injector is arranged within the exhaust stream, which can reach temperatures ranging from 500°C to 700°C, the reducing agent injector may be prone to overheating.
[0004] U.S. Patent No. 8,800,275, issued to Crandell et al. on August 12, 2014, discloses an engine exhaust assembly comprising a curved exhaust line having an exhaust flow from an upstream end to a downstream end. A recess includes an upstream wall and a downstream wall, the upstream wall extending at least partially into the curved portion of the exhaust line and disposed in the exhaust flow, the downstream wall being integrally formed with and located downstream of the upstream wall, the downstream wall having an inner surface oriented substantially facing the downstream end of the exhaust line and an outer surface substantially facing away from the downstream end of the exhaust line. A recess is integrally formed with the downstream wall and extends from the downstream wall in a direction remote from the downstream end of the exhaust line, and an orifice is formed in the recess. An injector is coupled to the outer surface of the downstream wall and has a nozzle aligned with the orifice of the recess.
[0005] The exhaust pipe disclosed herein solves one or more of the problems mentioned above and / or other problems in the art. Summary of the Invention
[0006] In some embodiments, the exhaust pipe includes: a first end having a first opening; a second end having a second opening in a plane, wherein the second opening is in fluid communication with the first opening to define a borehole for guiding exhaust flow; and a wall connecting the first end to the second end, wherein the wall includes: an inner portion including: a first inner linear segment adjacent to the first opening, a second inner linear segment adjacent to the second opening, and an inner curved segment connecting the first inner linear segment to the second inner linear segment; and an outer portion including: a first outer linear segment, the first outer linear segment... The system includes a first outer linear segment adjacent to the first opening, a second outer linear segment adjacent to the second opening, and an outer curved segment connecting the first outer linear segment to the second outer linear segment and including a notch for supporting a reducing agent injector. The notch includes: a first inward extension substantially perpendicular to the plane; a second inward extension substantially parallel to the plane; and a curved portion connecting the first inward extension to the second inward extension, wherein a first linear distance between the curved portion and the inner curved segment is substantially equal to a second linear distance between the first curved end and the second curved end of the inner curved segment.
[0007] In some embodiments, the exhaust pipe includes: a first end having a first opening; a second end having a second opening, wherein the second opening is in fluid communication with the first opening to define a borehole configured to guide exhaust flow from the first opening through the second opening; and a wall connecting the first end to the second end, wherein the wall includes: an inner portion including: a first inner linear segment adjacent to the first opening, a second inner linear segment adjacent to the second opening, and an inner curved segment within the first inner linear segment. The inner curved section extends between the first inner linear section and the second inner linear section, wherein the radius of curvature of the inner curved section increases as the inner curved section extends from the first inner linear section to connect with the second inner linear section, and an outer portion having a larger surface area than the inner portion, the outer portion comprising: a first outer linear section adjacent to a first opening, a second outer linear section adjacent to a second opening, and an outer curved section extending between the first outer linear section and the second outer linear section and including a notch for supporting the reducing agent injector.
[0008] In some embodiments, the exhaust pipe includes: a first end having a first opening; a second end having a second opening in a plane, wherein the second opening is in fluid communication with the first opening to define a borehole; and a wall connecting the first end to the second end, wherein the wall includes: an inner bend section and an outer bend section, the outer bend section including a notch including: a first inward extension substantially perpendicular to the plane, and a second inward extension substantially parallel to the plane and including a through hole having an inner opening and an outer opening, wherein the inner opening is located between the outer opening and the second opening, the diameter of the outer opening is smaller than the diameter of the inner opening, and the thickness of the second inward extension is smaller than the diameter of the outer opening. Attached Figure Description
[0009] Figure 1 This is an isometric view of the exemplary exhaust aftertreatment system described herein.
[0010] Figure 2 It is an exploded isometric view of the reducing agent injector and exhaust pipe of the exhaust aftertreatment system.
[0011] Figure 3 This is a cross-sectional side view of the exhaust pipe.
[0012] Figure 4 This is a front view of the exhaust pipe. Detailed Implementation
[0013] This disclosure relates to an exhaust pipe applicable to any system involving the combination of two or more fluids. For example, the system could be a power system, an exhaust aftertreatment system, etc. The system can be implemented in machines such as motor vehicles, rail vehicles, ships, aircraft, or other types of machinery.
[0014] To simplify the following description, the same reference numerals may be used to denote the same features. The figures may not be to scale.
[0015] Figure 1An exemplary exhaust aftertreatment system 100 is depicted. The exhaust aftertreatment system 100 includes a first filter canister 102, a second filter canister 104, an exhaust pipe 106 connecting the first filter canister 102 to the second filter canister 104, and a reducing agent injector mounted to the exhaust pipe 106. The first filter canister 102 is configured to filter exhaust stream 110 flowing from an engine (not shown) into the exhaust pipe 106. The exhaust stream 110 may include emission compounds such as hydrocarbons, particulate matter (e.g., soot and / or ash), and / or nitrous oxide (NOx). To treat hydrocarbons in the exhaust stream 110, the first filter canister 102 may include a diesel oxidation catalyst (DOC). A DOC is a flow-through filter for oxidizing hydrocarbons. Additionally or alternatively, the first filter canister 102 may include a diesel particulate filter (DPF) to filter particulate matter in the exhaust stream 110. A DPF is a wall-flow filter that traps particulate matter therein.
[0016] The second filter canister 104 is configured to filter exhaust stream 110 flowing into the environment from exhaust pipe 106. The second filter canister 104 includes a selective catalytic reduction (SCR) catalyst configured to reduce the NOx concentration in exhaust stream 110. To allow exhaust stream 110 to pass through it, the SCR catalyst may have a honeycomb structure or other porous structure.
[0017] The exhaust duct 106 is configured to guide exhaust flow 110 from the first filter canister 102 to the second filter canister 104. The exhaust duct 106 includes a first exhaust pipe 112 (described below in conjunction with...) Figures 2 to 4 (Description), second exhaust pipe 114 and third exhaust pipe 116 connecting the first exhaust pipe to the second exhaust pipe 114. Although the first exhaust pipe 112, the second exhaust pipe 114 and the third exhaust pipe 116 (collectively referred to herein as exhaust pipes) are shown as separate components held together by an annular clamp, it should be understood that two or more of the exhaust pipes may be integrally formed or attached by different types of fasteners.
[0018] The following will combine Figure 2 The described reducing agent injector 108 is configured to be installed in the first exhaust pipe 112 to distribute reducing agent flowing from a reducing agent source (not shown) into the exhaust stream 110. The reducing agent is a fluid configured to react with NOx in the exhaust stream 110 to convert NOx into other compounds (e.g., nitrogen dioxide (N2), water (H2O), and / or carbon dioxide (CO2)) before entering the second filter canister 104. For example, the reducing agent can be a urea solution (e.g., diesel exhaust fluid (DEF)), anhydrous ammonia, and / or ammonia solution.
[0019] As mentioned above, Figure 1It is provided as an instance. Other instances may differ from those provided. Figure 1 The described example. For instance, the number and arrangement of components may differ. Figure 1 The quantity and arrangement are shown. Therefore, with Figure 1 Compared to those shown, there may be additional components, fewer components, different components, components of different shapes, components of different sizes, and / or components with different arrangements.
[0020] Figure 2 The reducing agent injector 108 and the first exhaust pipe 112 (hereinafter referred to as exhaust pipe 112) are depicted. Figure 2 As shown, the reducing agent injector 108 includes an injector body 202, a gasket 204, and a plurality of fasteners 206 connecting the injector body 202 and the gasket 204 to an exhaust pipe 112. The injector body 202 includes a reducing agent port 208, a nozzle 210, a pair of coolant ports 212, and a plurality of orifices 214. The reducing agent port 208 is configured to receive reducing agent from a reducing agent source and to guide the reducing agent through the nozzle 210 into the exhaust pipe 112. The pair of coolant ports 212 are configured to receive coolant (e.g., an Inorganic Additive Technology (IAT) type coolant, an Organic Acid Technology (OAT) type coolant, and / or a Mixed Organic Acid Technology (HOAT) type coolant) from a coolant source (not shown). The coolant may be configured to cool components of the exhaust aftertreatment system 100 and / or defrost the reducing agent. The plurality of orifices 214 are configured to receive the plurality of fasteners 206 to allow the injector body 202 to be securely attached to the exhaust pipe 112. Washer 204 has a central hole 216 for receiving nozzle 210 and a plurality of peripheral holes 218 for receiving a plurality of fasteners 206. The plurality of fasteners 206 may include screws, bolts, bushings, washers and / or combinations thereof.
[0021] The following will be combined Figures 3 to 4 Further described, the exhaust pipe 112 is constructed and arranged to facilitate the uniform dispersion of the reducing agent into the exhaust flow 110. The exhaust pipe 112 includes a first end 220, a second end 222, and a wall 224 connecting the first end 220 to the second end 222. The first end 220, which may have a radius of curvature matching that of the first filter canister 102, includes a first opening 226 to receive the exhaust flow 110 from the first filter canister 102. It may be planar (e.g., as shown in the image). Figure 3As shown in plane 302, the second end 222, which mates with the planar end of the third exhaust pipe 116, includes a second opening 228 that is in fluid communication with the first opening 226 to define a borehole 230 for guiding the exhaust flow 110. To facilitate attachment of the exhaust pipe 112 between the first filter canister 102 and the second filter canister 104, the wall 224 includes a first flange 232 near the first end 220 and a second flange 234 near the second end 222. To support the reducing agent injector 108 and allow the reducing agent to pass through, the wall 224 includes a recess 236 having a through-hole 238 and a plurality of recesses 240. The through-hole 238 is configured to receive a nozzle 210, and the plurality of recesses are configured to receive a plurality of fasteners 206. In addition to other internal features of the exhaust pipe 112, the following will be combined with… Figures 3 to 4 Describe notch 236 and through hole 238 in detail.
[0022] As mentioned above, Figure 2 It is provided as an instance. Other instances may differ from those provided. Figure 2 The described example. For instance, the number and arrangement of components may differ. Figure 2 The quantity and arrangement are shown. Therefore, with Figure 2 Compared to those shown, there may be additional components, fewer components, different components, components of different shapes, components of different sizes, and / or components with different arrangements. For example, to simplify manufacturing and / or assembly, the injector body 202 can be directly mounted into the notch 236, without the gasket 204 located therein.
[0023] Figures 3 to 4 Exhaust pipe 112 is depicted. (Example) Figure 3 As shown, the wall includes an inner portion 304 and an outer portion 306, with the outer portion 306 having a larger surface area than the inner portion 304. The inner portion 304 includes a first inner linear segment 308, a second inner linear segment 310, and an inner curved segment 312 connecting the first inner linear segment 308 to the second inner linear segment 310. The first inner linear segment 308 is adjacent to a first opening 226, and the second inner linear segment 310 is adjacent to a second opening 228. To prevent stagnation within the exhaust flow 110 as it flows along the inner curved segment 312, the radius of curvature of the inner curved segment 312 increases as it extends from the first inner linear segment 308 to the second inner linear segment 310. In other words, the inner curved segment 312 has a flattened curvature that maintains the velocity of the exhaust flow 110 while guiding it to the central region of the exhaust pipe 112.
[0024] The outer portion 306 has a first outer linear segment 314, a second outer linear segment 316, and an outer curved segment 318 connecting the first outer linear segment 314 to the second outer linear segment 316. The first outer linear segment 314 is adjacent to a first opening 226, and the second outer linear segment 316 is adjacent to a second opening 228. The outer curved segment 318 includes a notch 236 opposite to the inner curved segment to form a neck 320 of the exhaust pipe 112. The notch 236 includes a first inward extension 322, a second inward extension 324, and a curved portion 326 connecting the first inward extension 322 to the second inward extension 324. To prevent stagnation within the exhaust flow 110 as it passes along the curved portion 326, the radius of curvature of the curved portion 326 is smaller than the radius of curvature of the inner curved segment 312.
[0025] The first inward extension 322, with a thickness less than that of the second inward extension, is substantially perpendicular to the plane 302. The second inward extension 324 is substantially parallel to the plane 302. The second inward extension 324 includes a through-hole 238, which is eccentric to the second opening 228 and extends at an obtuse angle α relative to the plane 302. The through-hole 238 includes an elliptical inner opening 328 and a circular outer opening 330. The inner opening 328 is located between the outer opening 330 and the second opening 228. The shape and size of the through-hole 238 facilitate the dispersion of the reducing agent into the exhaust stream 110. For example, as... Figure 4 As shown, the inner opening 328 has an upper portion 402 and a lower portion 404 that is narrower than the upper portion 402. As another example, the diameter of the inner opening 328 is larger than the diameter of the outer opening 330. The diameter of the outer opening 330 is larger than the thickness of the second inward extension 324.
[0026] The exhaust pipe 112 is made from a single, integral piece of metal (e.g., stainless steel). For example, the exhaust pipe 112 can be formed by casting. To guide the exhaust flow to a central region within the exhaust pipe 112, the first linear distance between the bend 326 and the inner bend section 312 is substantially equal to the second linear distance between the first bend end 332 and the second bend end 334 of the inner bend section 312. The first linear distance forming the neck 320 is less than the diameter of the first opening 226 and the diameter of the second opening 228. The ratio of the first linear distance to the diameter of the second opening 228 is less than 1:2. The ratio of the length of the first inward extension 322 to the diameter of the second opening 228 is less than 2:5.
[0027] As mentioned above, Figures 3 to 4 It is provided as an instance. Other instances may differ from those provided. Figures 3 to 4 As described. For example, the number and arrangement of components can be related to... Figures 3 to 4 The difference is shown. Therefore, compared to Figures 3 to 4Compared to those shown, there may be additional components, fewer components, different components, components of different shapes, components of different sizes, and / or components with different arrangements.
[0028] Industrial applicability
[0029] The exhaust pipe 112 disclosed herein is particularly suitable for systems that mix two or more fluids, such as exhaust aftertreatment system 100. Exhaust aftertreatment system 100 can be implemented in machines powered by internal combustion engines, such as motor vehicles, rail vehicles, ships, aircraft, or other types of machines.
[0030] Due to the precise curvature of the exhaust pipe 112, it ensures that the exhaust flow 110 flows along a substantially centered path at a sufficient velocity to uniformly mix the reducing agent. By eliminating stagnant areas within the exhaust flow 110, the exhaust pipe 112 suppresses the formation of deposits within the exhaust aftertreatment system 100. As a result, the exhaust pipe 112 is configured to reduce emissions, improve engine performance, and prevent flow blockage of the exhaust flow 110 that could potentially damage the exhaust aftertreatment system 100. Furthermore, due to the shape of the through-hole 238 and the second inward extension 324, the exhaust pipe 112 is configured to protect the reducing agent injector 108 from direct impact from the exhaust flow 110. As a result, the exhaust pipe 112 can minimize the possibility of overheating of the reducing agent injector 108.
[0031] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Modifications and variations can be made based on the foregoing disclosure, or can be derived from practice of the embodiments. Furthermore, any embodiments described herein can be combined unless the foregoing disclosure expressly provides a reason why one or more embodiments cannot be combined. Even if specific combinations of features are recited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various embodiments. Although each dependent claim listed below may be directly subordinated to only one claim, the disclosure of various embodiments includes each dependent claim combined with all other claims in the claim group.
[0032] As used herein, the terms “a,” “an,” and “a group” are intended to include one or more items and may be used interchangeably with “one or more.” Furthermore, as used herein, the article “the” is intended to include one or more items referenced in combination with the article “the” and may be used interchangeably with “the one or more.” Additionally, as used herein, the terms “comprises / comprising,” “having,” “including,” or other variations thereof are intended to cover non-exclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but may also include other elements not expressly listed. Furthermore, in this disclosure, relative terms such as “about,” “generally,” “substantially,” and “approximately” are used to indicate possible variations of ±10% in the values, unless otherwise apparent to a person of ordinary skill in the art in the context. Furthermore, unless expressly stated otherwise, the phrase “based on” is intended to mean “at least partially based on.” Furthermore, as used herein, the term “or,” when used in series, is intended to be inclusive and may be used interchangeably with “and / or”, unless expressly stated otherwise (e.g., if used in combination with “either” or “only one”). Furthermore, for ease of description, this document may use spatially relative terms such as “below,” “under,” “above,” “up,” etc., to describe the relationship between one element or feature and another element or feature illustrated in the figures. Spatially relative terms are intended to cover different orientations of the equipment, apparatus, and / or elements in use or operation other than those depicted in the figures. Equipment may be oriented in other ways (rotated 90 degrees or otherwise), and the spatially relative descriptors used herein may be interpreted accordingly.
Claims
1. An exhaust pipe (112), comprising: The first end (220) has a first opening (226); The second end (222) has a second opening (228) in the plane (302). The second opening (228) is in fluid communication with the first opening (226) to define a borehole (230) for guiding the exhaust flow (110). as well as Wall (224), which connects the first end (220) to the second end (222), wherein the wall (224) comprises: Internal portion (304), said internal portion (304) includes: The first inner linear segment (308) is adjacent to the first opening (226). The second inner linear segment (310), which is adjacent to the second opening (228), and An inner curved section (312) connects the first inner linear section (308) to the second inner linear section (310), and The outer portion (306) includes: The first outer linear segment (314) is adjacent to the first opening (226). The second outer linear segment (316), which is adjacent to the second opening (228), and An outer curved section (318) connects the first outer linear section (314) to the second outer linear section (316) and includes a notch (236) for supporting the reducing agent injector (108), the notch (236) comprising: The first inward extension (322) is substantially perpendicular to the plane (302). A second inward extension (324), which is substantially parallel to the plane (302) and includes a through hole (238), and A bend (326) connects the first inward extension (322) to the second inward extension (324). The first linear distance between the curved portion (326) and the inner curved section (312) is substantially equal to the second linear distance between the first curved end (332) and the second curved end (334) of the inner curved section (312); The through hole (238) is eccentric to the second opening (228) and extends at an obtuse angle (α) relative to the plane (302), and the through hole (238) includes an elliptical inner opening (328) and a circular outer opening (330), the inner opening (328) being located between the outer opening (330) and the second opening (228).
2. The exhaust pipe (112) according to claim 1, wherein the ratio of the first linear distance to the diameter of the second opening (228) is less than 1:
2.
3. The exhaust pipe (112) according to any one of claims 1 to 2, wherein The first inward extension (322) has a length; and The ratio of the length to the diameter of the second opening (228) is less than 2:
5.
4. The exhaust pipe (112) according to any one of claims 1 to 3, wherein the thickness of the first inward extension (322) is less than the thickness of the second inward extension (324).
5. An exhaust pipe (112), comprising: The first end (220) has a first opening (226); The second end (222) has a second opening (228) in the plane (302), wherein The second opening (228) is in fluid communication with the first opening (226) to define the borehole (230); as well as Wall (224), which connects the first end (220) to the second end (222), wherein the wall (224) comprises: The inner curved section (312), and An outwardly curved section (318) includes a notch (236), the notch (236) comprising: The first inward extension (322) is substantially perpendicular to the plane (302), and A second inward extension (324) is substantially parallel to the plane (302) and includes a through hole (238) having an elliptical inner opening (328) and a circular outer opening (330). The through hole (238) is eccentric to the second opening (228) and extends at an obtuse angle (α) relative to the plane (302). The inner opening (328) is located between the outer opening (330) and the second opening (228). The diameter of the outer opening (330) is smaller than the diameter of the inner opening (328), and The thickness of the second inward extension (324) is less than the diameter of the outer opening (330).
6. The exhaust pipe (112) according to claim 5, wherein the first end (220) is non-planar.
7. The exhaust pipe (112) according to any one of claims 5 to 6, wherein the inner opening (328) has an upper portion (402) and a lower portion (404) that is narrower than the upper portion (402).
8. The exhaust pipe (112) according to any one of claims 5 to 6, wherein the notch (236) further comprises a bend (326) that connects the first inward extension (322) to the second inward extension (324) and faces the inward bend section (312).