The present disclosure relates generally to exhaust systems.
Exhaust systems include an exhaust manifold, one or more exhaust aftertreatment devices, and pipes connecting these components. In some arrangements, the pipes include bends to route the exhaust gas along a non-linear path.
One embodiment relates to a method that includes providing first and second half-pipe sections. Each of the first and second half-pipe sections includes a first curved portion and defines a first outer edge length. Third and fourth half-pipe sections are provided. Each of the third and fourth half-pipe sections includes a second curved portion and defines a second outer edge length. The second outer edge length is longer than the first outer edge length. The first half-pipe section is welded to the third half-pipe section so as to form a first half-pipe subassembly. The second half-pipe section is welded to the fourth half-pipe section so as to form a second half-pipe subassembly. The first half-pipe subassembly is welded to the second half-pipe subassembly so as to form an exhaust tube section.
Another embodiment relates to an exhaust tube section. The exhaust tube section includes first, second, third, and fourth half-pipe sections. The first and third half-pipe sections are welded to one another, forming a first half-pipe subassembly. The second and fourth half-pipe sections are welded to one another, forming a second half-pipe subassembly. Each of the first and second half-pipe sections includes a first curved portion and has a first outer edge length. Each of the third and fourth half-pipe sections includes a second curved portion and has a second outer edge length. The second outer edge length is longer than the first outer edge length.
Another embodiment relates to a system. The system includes an exhaust assembly, which includes a first straight portion structured to be fluidly coupled to an engine. The exhaust assembly also includes a second straight portion structured to be fluidly coupled to an exhaust aftertreatment component. A bend portion is fluidly coupled to each of the first and second straight portions. The bend portion includes first, second, third, and fourth half-pipe sections. A first half-pipe subassembly includes the first and third half-pipe sections welded to one another. A second half-pipe subassembly is welded to the first half-pipe subassembly. The second half-pipe subassembly includes the second and fourth half-pipe sections welded to one another. Each of the first and second half-pipe sections includes a first curved portion and has a first outer edge length. Each of the third and fourth half-pipe sections includes a second curved portion and has a second outer edge length. The second outer edge length is longer than the first outer edge length.
These and other features, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like elements have like numerals throughout the several drawings described below.
The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the disclosure will become apparent from the description, the drawings, and the claims.
It will be recognized that some or all of the figures are schematic representations for purposes of illustration. The figures are provided for the purpose of illustrating one or more implementations with the explicit understanding that they will not be used to limit the scope or the meaning of the claims.
The exhaust assembly 100 includes a first pipe section 102 and a second pipe section 104. The first pipe section 102 extends between a first inlet 106 and a first outlet 108. The second pipe section 104 extends between a second inlet 110 and a second outlet 112. The first and second inlets 106, 110 are structured to be fluidly coupled to an engine (not shown) so as to be in exhaust gas receiving communication with the engine. The first and second outlets 108, 112 are structured to be fluidly coupled to an exhaust aftertreatment component so as to be in exhaust gas providing communication to the exhaust aftertreatment component. For example, in one embodiment, the first and second outlets 108, 112 are structured to be fluidly coupled to a decomposition reactor.
As illustrated in
According to various embodiments, the first and second pipe sections 102, 104 each comprise a plurality of components that are assembled to form the first and second pipe sections 102, 104. For example, the first pipe section 102 comprises a first straight portion 118, a bend portion 120, and a second straight portion 122. The bend portion 120 is fluidly coupled to each of the first and second straight portions 118, 122. As will be appreciated, each of the first straight portion 118, the bend portion 120, and the second straight portion 122 may be formed from a plurality of sub-components. In some embodiments, the first straight portion 118, the bend portion 120, and the second straight portion 122 are formed from sheet metal, such as steel or aluminum.
In operation, exhaust gas flows into the first inlet 106 and through a first straight portion 118 along a first flow direction 124, which is substantially parallel to the first central axis 114. The exhaust gas flows from the first straight portion 118 into the bend portion 120. The exhaust gas then flows from the bend portion 120 into the second straight portion 122 along a second flow direction 126, which is substantially parallel to the second central axis 116. The first and second flow directions 124, 126 are opposite each other. In other words, the first and second flow directions 124, 126 are oriented about 180 degrees from each other. The bend portion 120 is generally “U-shaped” so as to reverse a flow direction of the exhaust gas flowing therethrough from the first flow direction 124 to the second flow direction 126.
There are several manufacturing challenges associated with constructing the bend portion 120. One method of manufacturing the bend portion 120 is to bend a single pipe using a mandrel. One side effect of bending a pipe is that the wall thickness changes. In particular, the wall along the inner radius becomes thicker and the wall along the outer radius becomes thinner. These effects are typically more problematic the smaller the radius (the tighter the bend) and the larger the cross-sectional diameter of the pipe. The exhaust assembly 100 illustrated in
Another method of manufacturing the bend portion 120 is to weld together several half-pipe sections. For example, in some conventional systems, the bend portion 120 is manufactured by welding together four half-pipe sections. In some conventional systems, each of the four half-pipe sections is a unique part, which increases the total unique part count of the system. This increases the complexity and cost of bill of materials (“BOM”) and part order management. In addition, poka-yoke (mistake-proofing) becomes more difficult with more unique parts.
Various embodiments relate to a sheet metal tube with a 180 degree bend, and a method of manufacturing the same. According to an embodiment, four half-pipe sections are provided. The four half-pipe sections comprise two unique parts. For example, first and second half-pipe sections have a first shape and third and fourth half-pipe sections have a second shape different than the first shape. The first and third half-pipe sections are welded together so as to form a first half-pipe subassembly, and the second and fourth half-pipe sections are welded together so as to form a second half-pipe subassembly. The first and second half-pipe assemblies are welded together so as to form an exhaust tube section with a 180 degree bend.
In some embodiments, the first and third half-pipe sections (and therefore also the second and fourth half pipe sections) are shaped so that a weld seam is off-center relative to a radius of the bend portion. For example, in some embodiments, each of the first and second half-pipe sections have a first outer edge length, and each of the third and fourth half-pipe sections have a second outer edge length that is longer than the first outer edge length. When the two half-pipe subassemblies are positioned to be welded, one of the half-pipe subassemblies is flipped relative to the other half-pipe subassembly. Therefore, the weld seams of each of the first and second half-pipe assemblies are not aligned, but are rather offset from each other. In operation, offsetting the weld seams minimizes heat concentrations formed at the weld seams.
The exhaust tube section 200 comprises first, second, third, and fourth half-pipe sections 202, 204, 206, 208 that are welded together to form the exhaust tube section 200. The first and second half-pipe sections 202, 204 each have a first shape and the third and fourth half-pipe sections 206, 208 have a different second shape. Accordingly, the first and second half-pipe sections 202, 204 comprise a first unique part in a BOM of the exhaust tube section 200, and the third and fourth half-pipe sections 206, 208 comprise a second unique part in the BOM. As described in further detail in connection with
The first and third half-pipe sections 202, 206 are welded together to form a first half-pipe subassembly 218 having a first weld seam 220. The second and fourth half-pipe sections 204, 208 are welded together to form a second half-pipe subassembly 222 having a second weld seam 224. The first and second half-pipe subassemblies 218, 222 are welded together to form the exhaust tube section 200. As illustrated in
The first inlet 302 defines a first central axis 306 of the first half-pipe section 202. The first inlet 302 has a constant radius relative to the first central axis 306. The first central axis 306 is perpendicular to a plane defined by the first inlet 302. Similarly, the first outlet 304 defines a second central axis 308 of the first half-pipe section 202. The first outlet 304 has a constant radius relative to the second central axis 308. The second central axis 308 is perpendicular to a plane defined by the first outlet 304. According to various embodiments, the first and second central axes 306, 308 are not parallel. In some embodiments, the first and second central axes 306, 308 are perpendicular.
The first half-pipe section 202 has a first inner edge 310 and a first outer edge 312. The first inner edge 310 defines a first inner edge length extending between the first inlet 302 and the first outlet 304. Similarly, the first outer edge 312 defines a first outer edge length extending between the first inlet 302 and the first outlet 304. The first half-pipe section 202 includes a first straight portion 314 and a first curved portion 316. The first curved portion 316 defines a 90 degree bend, which is structured to change a flow direction of exhaust gas flowing therethrough by 90 degrees. As illustrated in
The third half-pipe section 206 has a second inner edge 410 and a second outer edge 412. The second inner edge 410 defines a second inner edge length extending between the second inlet 402 and the second outlet 404. Similarly, the second outer edge 412 defines a second outer edge length extending between the second inlet 402 and the second outlet 404. The third half-pipe section 206 includes a second straight portion 414 and a second curved portion 416. The second curved portion 416 defines a 90 degree bend, which is structured to change a flow direction of exhaust gas flowing therethrough by 90 degrees. Because the first curved portion 316 of the first half-pipe section 202 and the second curved portion 416 of the third half-pipe section 206 each change the flow direction of the exhaust gas flowing therethrough by 90 degrees, the assembled exhaust tube section 200 is structured to change the flow direction of the exhaust gas flowing therethrough by 180 degrees. As illustrated in
It should be understood that angle values described herein are intended to include the nominal stated value ±5 percent. For example, a 180 degree bend or angle may include a bend or angle between about 171 degrees and 189 degrees. Similarly, a 90 degree bend may or angle may include a bend or angle between about 85.5 degrees and 94.5 degrees.
At 802, first and second half-pipe sections 202, 204 are provided. Each of the first and second half-pipe sections 202, 204 includes a first curved portion and defines a first outer edge length. For example, the first half-pipe section 202 includes the first curved portion 316 and defines the first outer edge length 210. The second half-pipe section 204 also similarly includes a corresponding curved portion and outer edge length. In some embodiments, the first curved portion 316 defines a first bend of about 90 degrees.
At 804, third and fourth half-pipe sections 206, 208 are provided. Each of the third and fourth half-pipe sections 206, 208 includes a second curved portion and defines a second outer edge length. For example, the third half-pipe section 206 includes the second curved portion 416 and defines the second outer edge length 212. The fourth half-pipe section 208 also similarly includes a corresponding curved portion and outer edge length. The second outer edge length 212 of the third and fourth half-pipe sections 206, 208 is longer than the first outer edge length 210 of the first and second half-pipe sections 202, 204. In some embodiments, the second curved portion 416 defines a second bend of about 90 degrees.
At 806, the first half-pipe section 202 is welded to the third half-pipe section 206 so as to form the first half-pipe subassembly 600. The first weld seam 220 is formed upon welding the first and third half-pipe sections 202, 206.
At 808, the second half-pipe section 204 is welded to the fourth half-pipe section 208 so as to form the second half-pipe subassembly 700. The second weld seam 224 is formed upon welding the second and fourth half-pipe sections 204, 208.
At 810, the first half-pipe subassembly 700 is welded to the second half-pipe subassembly 800 so as to form the exhaust tube section 200. The first and second weld seams 220, 224 are not aligned in the completed exhaust tube section 200. Instead, the first and second weld seams 220, 224 are offset because the first and second outer edge lengths 210, 212 are different. In some embodiments, the exhaust tube section 200 is structured to change a flow direction of exhaust gas flowing therethrough by about 180 degrees.
In some embodiments, each of the first and second half-pipes 902, 904, and the first, second, third, and fourth half-pipe sections 202, 204, 206, 208 are formed from stamped sheet metal. One side-effect of stamping or otherwise plastically deforming sheet metal is that certain areas of a part (e.g., those areas deformed significantly) may exhibit wall thickness distortion and stress concentrations. In general, for a given part formed from sheet metal having a given raw material thickness, the larger the part, the greater the wall thickness distortion and stress concentrations.
In some embodiments, the one-piece first and second half-pipes 902, 904 are utilized for exhaust tubes having a diameter that is less than a threshold diameter. In contrast, the first and second half-pipe subassemblies 600, 700 formed from multiple pieces are utilized for exhaust tubes having a diameter that is the threshold diameter or greater. For example, in one embodiment, the threshold diameter is five inches. Accordingly, the first and second half-pipes 902, 904, each having been formed from a single piece, are utilized for exhaust tubes having a diameter that is less than five inches. The first and second half-pipe subassemblies 600, 700, each having been formed from multiple (e.g., two) pieces, are utilized for exhaust tubes having a diameter that is five inches or greater.
One benefit to utilizing the one-piece first and second half-pipes 902, 904 is that the first and second weld seams 220, 224 are eliminated. Accordingly, the first and second half-pipes 902, 904 may be identical parts. In contrast, different shaped parts were utilized for the half-pipe sections of the half-pipe subassemblies 600, 700 so that the first and second weld seams 220, 224 are offset.
It should be understood that no claim element herein is to be construed under the provisions of 35 U.S.C. § 112(f), unless the element is expressly recited using the phrase “means for.” The schematic flow chart diagrams and method schematic diagrams described above are generally set forth as logical flow chart diagrams. As such, the depicted order and labeled steps are indicative of representative embodiments. Other steps, orderings and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the methods illustrated in the schematic diagrams. Further, reference throughout this specification to “one embodiment,” “an embodiment,” “an example embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” “in an example embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
Additionally, the format and symbols employed are provided to explain the logical steps of the schematic diagrams and are understood not to limit the scope of the methods illustrated by the diagrams. Although various arrow types and line types may be employed in the schematic diagrams, they are understood not to limit the scope of the corresponding methods. Indeed, some arrows or other connectors may be used to indicate only the logical flow of a method. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of a depicted method. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and program code.
Accordingly, the present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.