Exhaust parts
The exhaust component with a double-pipe structure and negative pressure zones addresses the issue of exhaust leakage by guiding exhaust flow into the inner pipe, effectively suppressing leakage and reducing sound pressure in both flow directions.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- FUTABA IND CO LTD
- Filing Date
- 2024-12-23
- Publication Date
- 2026-07-03
AI Technical Summary
Existing exhaust silencers face challenges in effectively suppressing exhaust gas leakage to the outside, whether the exhaust flows from upstream to downstream or from downstream to upstream, due to the inability to maintain negative pressure near the outer through holes.
The exhaust component features a double-pipe structure with a shell member and an inner pipe, where the inner pipe is inserted into the shell member, and includes features such as shell and inner holes, a separator, and tapered sections to create negative pressure zones that prevent exhaust leakage by guiding the flow into the inner pipe.
This configuration effectively suppresses exhaust gas leakage by generating negative pressure in the internal space, redirecting exhaust flow into the inner pipe, and reducing sound pressure to prevent standing waves, regardless of the flow direction.
Smart Images
Figure 2026111239000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to exhaust components.
Background Art
[0002] Patent Document 1 below describes an exhaust silencer that forms an exhaust passage of an internal combustion engine. The exhaust silencer includes an inner tubular member and an outer tubular member that covers the outside of the inner tubular member. The exhaust silencer has a double pipe structure in which the inner tubular member is inserted into the outer tubular member so as to penetrate from one end to the other end of the outer tubular member. The inner tubular member has a plurality of inner through holes, and the outer tubular member has outer through holes on the upstream side in the exhaust direction from the plurality of inner through holes. In Patent Document 1, by providing the inner through holes and the outer through holes, an attempt is made to reduce the sound pressure when column resonance sound occurs and suppress standing waves.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] Here, in the exhaust silencer, the exhaust flowing through the inner tubular member tends to flow to the downstream side in the exhaust direction from the inner through holes after passing through the inner through holes. Therefore, the vicinity of the outer through holes on the upstream side can be made negative pressure. As a result, when the exhaust flows from the upstream side to the downstream side, it is possible to suppress the exhaust from leaking to the outside through the outer through holes.
[0005] However, when the exhaust flows from the downstream side to the upstream side, the vicinity of the outer through holes cannot be made negative pressure, so there is a possibility that the exhaust leaks to the outside through the outer through holes. One aspect of this disclosure is to provide an exhaust component that suppresses exhaust leakage to the outside, whether the exhaust flows from upstream to downstream or from downstream to upstream. [Means for solving the problem]
[0006] One aspect of the present disclosure is an exhaust component. The exhaust component is a member that forms an exhaust flow path and comprises a shell member and an inner pipe, both of which are tubular members. The inner pipe penetrates a first shell end, which is one end of the shell member, and is inserted into the shell member along the extension direction, which is the direction in which the shell member extends. The first inner end, which is one end of the inner pipe, is open to the outside of the shell member. The second inner end, which is the end of the inner pipe opposite to the first inner end, is located in the internal space surrounded by the shell member. The side surface of the shell member is provided with a shell hole, which is a hole that communicates the internal space with the atmosphere. The side surface of the inner pipe is provided with an inner hole, which is a hole. The shell hole is located on the first shell end side of the inner hole. Within the internal space, in the space formed between the side surface of the shell member and the side surface of the inner pipe, a narrow section is formed at a first position in the side space, which is the space between the shell hole and the inner hole, where the cross-sectional area of the section perpendicular to the extension direction is relatively smaller than that of a second position, which is any other position in the side space.
[0007] This configuration produces the following effects and benefits. Specifically, when exhaust gas flows from the first shell end towards the second shell end, the exhaust gas that has passed through the second inner end tends to flow further towards the second shell end, thus creating negative pressure near the second inner end. This negative pressure in the internal space causes air to flow into the internal space through the shell opening. Therefore, a flow of air from the outside into the internal space occurs near the shell opening, suppressing exhaust gas leakage from the internal space to the outside.
[0008] Furthermore, when exhaust flows from the second shell end towards the first shell end, a constriction occurs in the exhaust flowing into the inner pipe. As a result, negative pressure is generated in the space surrounded by the inner pipe. Here, the exhaust flowing into the space sandwiched between the side of the shell member and the side of the inner pipe is obstructed by the constriction, making it difficult for it to flow towards the first shell end beyond the constriction. Also, because negative pressure is generated in the space surrounded by the inner pipe, the exhaust flows into the inner pipe from the inner hole. As a result, leakage of exhaust to the outside from the shell hole located on the first shell end side of the constriction is suppressed.
[0009] In this way, exhaust gas leakage to the outside can be suppressed whether the exhaust gas flows from the first shell end to the second shell end or from the second shell end to the first shell end. In other words, regardless of whether the first shell end or the second shell end is located on the upstream or downstream side in the exhaust direction, exhaust gas leakage to the outside can be suppressed whether the exhaust gas flows from upstream to downstream or from downstream to upstream.
[0010] In one aspect of this disclosure, the vicinity of the second shell end, which is the end of the shell member opposite to the first shell end, may be configured such that the cross-sectional area of the section perpendicular to the extension direction decreases as it moves away from the first shell end.
[0011] With this configuration, as you move from the first shell end towards the second shell end, the cross-sectional area near the second shell end decreases. Therefore, when exhaust gas flows from the first shell end towards the second shell end, the exhaust gas flowing out from the second shell end is more likely to contract. Consequently, negative pressure is more likely to be generated in the internal space. Therefore, air is more likely to flow from the outside into the internal space near the shell opening, thus further suppressing exhaust gas leakage from the internal space to the outside.
[0012] In one aspect of this disclosure, a separator may be provided at a first position in the side space, which is a member having a surface that extends in a direction intersecting the extension direction. The separator may form a narrowed portion.
[0013] With this configuration, when exhaust gas flows from the second shell end towards the first shell end, the separator can block the exhaust gas that flows into the space between the side of the shell member and the side of the inner pipe. The exhaust gas is then bent by the separator, making it easier for it to flow from the inner hole into the inner pipe. In other words, by using a separator, the exhaust gas flow path can be changed with a simple structure.
[0014] In one aspect of this disclosure, the vicinity of the second inner end of the inner pipe may have a portion configured such that the cross-sectional area of the cross section perpendicular to the extension direction increases as it moves away from the first inner end.
[0015] With this configuration, when exhaust flows from the second shell end towards the first shell end, the exhaust flowing into the inner pipe is more likely to contract. Therefore, negative pressure is more likely to be generated in the space surrounded by the inner pipe. Consequently, exhaust flows more easily from the inner hole into the inner pipe. This suppresses the flow of exhaust towards the shell hole.
[0016] In one aspect of this disclosure, the exhaust component may be mounted on a vehicle. The first shell end and the first inner end may be provided on the upstream side in the exhaust direction, which is the direction in which exhaust gas flows from the engine. With such a configuration, exhaust gas flowing in from the upstream side can be smoothly guided into the inner pipe and flowed downstream. [Brief explanation of the drawing]
[0017] [Figure 1] This is a schematic cross-sectional view of the exhaust component of the first embodiment. It also serves to illustrate the exhaust flow when the exhaust flows from the upstream side to the downstream side. [Figure 2]It is a schematic cross-sectional view of an exhaust component according to the first embodiment. It is also a diagram for explaining the flow of exhaust when the exhaust flows from the downstream side to the upstream side. [Figure 3] FIG. 3A is a front view of the separator, FIG. 3B is a rear view of the separator, FIG. 3C is a front perspective view of the separator, and FIG. 3D is a rear perspective view of the separator. [Figure 4] It is a schematic cross-sectional view of an exhaust component according to the second embodiment. [Figure 5] It is a schematic cross-sectional view of an exhaust component according to Modification 1. [Figure 6] FIG. 6A is a schematic cross-sectional view of an exhaust component according to Modification 2, and FIG. 6B is a schematic cross-sectional view of an exhaust component according to Modification 3. [Figure 7] It is a schematic cross-sectional view of an exhaust component according to Modification 4. [Modes for Carrying Out the Invention]
[0018] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. Embodiment] [1-1. Configuration] The exhaust component 100 shown in FIGS. 1 and 2 is a component that is mounted on a vehicle and forms an exhaust flow path. As an example, the exhaust component 100 may be configured as a muffler that forms an exhaust flow path from an engine. More specifically, the exhaust component 100 may be configured as a sub-muffler. The direction in which the exhaust from the engine flows is referred to as the exhaust direction.
[0019] The exhaust component 100 includes a shell member 1, an inner pipe 2, and a separator 3. The shell member 1 and the inner pipe 2 are members that form an exhaust flow path and are tubular members. More specifically, the shell member 1 and the inner pipe 2 are pipes having a substantially cylindrical shape as a whole. The exhaust component 100 has a double-pipe structure, where the shell member 1 corresponds to the outer pipe and the inner pipe 2 corresponds to the inner pipe. The central axis of the shell member 1 in the direction in which the shell member 1 extends and the central axis of the inner pipe 2 in the direction in which the inner pipe 2 extends are substantially the same. Hereinafter, the extension direction, which is the direction in which the shell member 1 extends, is also referred to as the front-rear direction. The front is the upstream side in the exhaust direction, and the rear is the downstream side in the exhaust direction. Note that this direction is defined for convenience of explanation and does not limit the usage mode of the exhaust component 100.
[0020] [1-1-1. Shell Member] The shell member 1 includes a first shell edge portion 10A, a second shell edge portion 10B, a first shell taper portion 11A, a second shell taper portion 11B, a shell central portion 12, and a shell hole portion 13. A first shell end portion 14A, which is one end of the shell member 1, and a second shell end portion 14B, which is the end opposite to the first shell end portion 14A in the shell member 1, are open. The openings formed in the first shell end portion 14A and the second shell end portion 14B have a substantially circular shape. When the exhaust flows from the upstream side to the downstream side, the first shell end portion 14A serves as the inlet of the exhaust of the exhaust component 100, and the second shell end portion 14B serves as the outlet of the exhaust of the exhaust component 100.
[0021] The first shell edge portion 10A is a substantially cylindrical portion that extends rearward from the first shell end portion 14A. The second shell edge portion 10B is a substantially cylindrical portion that extends forward from the second shell end portion 14B. The diameter of the first shell edge portion 10A and the diameter of the second shell edge portion 10B are substantially the same. The inner peripheral surface of the second shell edge portion 10B is joined to the outer peripheral surface of the downstream exhaust pipe 5. The downstream exhaust pipe 5 is a tubular member that extends downstream of the exhaust component 100 and may be, for example, a tail pipe.
[0022] The first shell tapered portion 11A is the part that connects the first shell edge portion 10A and the shell center portion 12. The first shell tapered portion 11A is configured such that the cross-sectional area of the cross section perpendicular to the front-rear direction increases as it moves away from the first shell end portion 14A. In other words, the diameter of the first shell tapered portion 11A decreases as it moves away from the second shell end portion 14B.
[0023] The second shell tapered portion 11B is the part that connects the second shell edge portion 10B and the shell center portion 12. The second shell tapered portion 11B is configured such that the cross-sectional area of the section perpendicular to the front-rear direction increases as it moves away from the second shell end portion 14B. In other words, the second shell tapered portion 11B is configured such that the cross-sectional area of the section perpendicular to the front-rear direction decreases as it moves away from the first shell end portion 14A. In other words, the diameter of the second shell tapered portion 11B decreases as it moves away from the first shell end portion 14A. For example, the first shell tapered portion 11A and the second shell tapered portion 11B may be formed by spinning.
[0024] The central shell portion 12 is a substantially cylindrical part that extends along the front-to-back direction. The central shell portion 12 is located between the first shell tapered portion 11A and the second shell tapered portion 11B. The diameter of the central shell portion 12 is larger than the diameter of the first shell edge portion 10A and the diameter of the second shell edge portion 10B.
[0025] The shell hole portion 13 is a hole provided on the side surface of the shell member 1, allowing communication between the internal space 6 surrounded by the shell member 1 and the atmosphere. The shell hole portion 13 is provided in front of the separator 3. In other words, the shell hole portion 13 is provided between the first shell end portion 14A and the separator 3 in the front-rear direction. In this embodiment, the shell hole portion 13 includes multiple holes and is provided collectively on a part of the side surface of the central part 12 of the shell.
[0026] [1-1-2. Inner Pipe] The inner pipe 2 comprises a first inner edge 20A, a second inner edge 20B, a first inner tapered portion 21A, a second inner tapered portion 21B, an inner central portion 22, and an inner hole portion 23. One end of the inner pipe 2, the first inner end 24A, and the end of the inner pipe 2 opposite to the first inner end 24A, the second inner end 24B, are open. The openings formed in the first inner end 24A and the second inner end 24B have a substantially circular shape. When exhaust flows from the upstream side to the downstream side, the first inner end 24A becomes the exhaust inlet, and the second inner end 24B becomes the exhaust outlet.
[0027] The first inner edge portion 20A is a substantially cylindrical portion that extends rearward from the first inner end portion 24A. The second inner edge portion 20B is a substantially cylindrical portion that extends forward from the second inner end portion 24B. The diameter of the second inner edge portion 20B is slightly larger than the diameter of the first inner edge portion 20A.
[0028] The first inner tapered portion 21A is the part that connects the first inner edge portion 20A and the inner central portion 22. The first inner tapered portion 21A is configured such that the cross-sectional area of the cross section perpendicular to the front-rear direction decreases as it moves away from the first inner end portion 24A. In other words, the diameter of the first inner tapered portion 21A increases as it moves away from the second inner end portion 24B.
[0029] The second inner tapered portion 21B is the part that connects the second inner edge portion 20B and the central portion 12 of the shell. The second inner tapered portion 21B is configured such that the cross-sectional area of the section perpendicular to the front-rear direction decreases as it moves away from the second inner end portion 24B. In other words, the second smaller tapered portion is configured such that the cross-sectional area of the section perpendicular to the front-rear direction increases as it moves away from the first inner end portion 24A. To put it another way, the second inner tapered portion 21B expands in diameter as it moves away from the first inner end portion 24A.
[0030] The inner central portion 22 is a substantially cylindrical portion that extends along the front-to-back direction. The inner central portion 22 is located between the first inner tapered portion 21A and the second inner tapered portion 21B. The diameter of the inner central portion 22 is smaller than the diameter of the first inner edge portion 20A and the diameter of the second inner edge portion 20B.
[0031] The inner hole portion 23 is a hole provided on the side surface of the inner member. The inner hole portion 23 connects the space formed between the side surface of the shell member 1 and the side surface of the inner pipe 2 with the space surrounded by the inner member. The inner hole portion 23 is provided behind the separator 3. In other words, the inner hole portion 23 is provided between the separator 3 and the second inner end portion 24B in the front-rear direction. That is, the shell hole portion 13, separator 3, and inner hole portion 23 are arranged in order from the first shell end portion 14A side (i.e., the front side). In this embodiment, the inner hole portion 23 includes multiple holes and is provided in a circumferential direction so as to encircle the side surface of the inner central portion 22.
[0032] The inner pipe 2 penetrates the first shell end 14A of the shell member 1 and is inserted into the shell member 1 along the front-rear direction. The first inner end 24A is positioned to lead to the outside of the shell member 1. More specifically, the first shell end 14A and the first inner end 24A are positioned at approximately the same location in the front-rear direction. The outer circumferential surface of the first inner edge 20A is joined to the inner circumferential surface of the first shell edge 10A. The inner circumferential surface of the first inner edge 20A is joined to the outer circumferential surface of the upstream exhaust pipe 4. The upstream exhaust pipe 4 is a tubular member that extends upstream of the exhaust component 100, and may be, for example, a front pipe.
[0033] The second inner end portion 24B is located in the internal space 6. In other words, the second inner end portion 24B does not penetrate the second shell end portion 14B and is located in front of the second shell end portion 14B. In this embodiment, the second inner end portion 24B is located behind the center of the shell member 1 in the front-rear direction and in front of the second shell tapered portion 11B.
[0034] [1-1-3. Separator] As shown in Figures 3A to 3D, the separator 3 has an annular shape overall. The separator 3 comprises a plate portion 30, a first wall portion 31, and a second wall portion 32. The plate portion 30 is an annular plate.
[0035] The first wall portion 31 is a wall erected from the inner edge of the plate portion 30. More specifically, the first wall portion 31 is provided along the inner edge of the plate portion 30, encircling the inner edge of the plate portion 30. The second wall portion 32 is a wall erected from the outer edge of the plate portion 30. More specifically, the second wall portion 32 is provided along the outer edge of the plate portion 30, encircling the outer edge of the plate portion 30. The first wall portion 31 and the second wall portion 32 are erected so as to extend substantially parallel to each other. In other words, an annular groove is formed in the separator 3. The ridge line formed by the plate portion 30 and the first wall portion 31, and the ridge line formed by the plate portion 30 and the second wall portion 32 may have a gentle shape.
[0036] As shown in Figures 1 and 2, the separator 3 is provided in the side space 60. The side space 60 is the space formed between the side surface of the shell member 1 and the side surface of the inner pipe 2 within the internal space 6, and is the space between the shell hole 13 and the inner hole 23. In other words, the separator 3 is provided at a position between the shell hole 13 and the inner hole 23 in the front-rear direction.
[0037] When the separator 3 is positioned in the side space 60, the surface of the plate portion 30 spreads out in a direction that intersects the front-rear direction. In this embodiment, the surface of the plate portion 30 spreads out in a planar shape perpendicular to the front-rear direction. The separator 3 is positioned such that the first wall portion 31 and the second wall portion 32 protrude rearward from the plate portion 30.
[0038] The outer circumferential surface of the second wall portion 32 is joined to the inner circumferential surface of the shell member 1. The inner circumferential surface of the first wall portion 31 is positioned opposite the outer circumferential surface of the inner pipe 2. In other words, the inner pipe 2 is inserted into a circular hole formed by being surrounded by the first wall portion 31. A gap is formed between the inner circumferential surface of the first wall portion 31 and the outer circumferential surface of the inner pipe 2. In other words, the inner circumferential surface of the first wall portion 31 and the outer circumferential surface of the inner pipe 2 are not in contact.
[0039] When the cross section perpendicular to the front-rear direction at the first position 61A, where the separator 3 is positioned in the side space 60, is defined as the first cross section, and the cross section perpendicular to the front-rear direction at the second position 61B, which is any position in the side space 60 other than the first position 61A, is defined as the second cross section, the cross-sectional area of the space in the first cross section is smaller than the cross-sectional area of the space in the second cross section. In other words, a narrow section 61 is formed at the first position 61A, which is a space in which the cross-sectional area perpendicular to the front-rear direction is relatively smaller than that at the second position 61B. The narrow section 61 is an annular space formed between the first wall 31 and the side surface of the inner pipe 2.
[0040] In other words, the exhaust flow path formed at the first position 61A is configured to be narrower than the exhaust flow path formed at the second position 61B. That is, the exhaust flow path in the narrower portion 61 of the side space 60 is relatively narrower. In this embodiment, in the side space 60, at the first position 61A, the exhaust flow path is narrower by the area of the surface of the plate portion 30 of the separator 3.
[0041] [1-2. Exhaust Flow] Figure 1 is used to explain the exhaust flow when the exhaust flows from upstream to downstream (hereinafter referred to as forward flow).
[0042] The exhaust from the engine, flowing through the upstream exhaust pipe 4, enters the inner pipe 2 from the first shell end 14A and the first inner end 24A. The exhaust that has passed through the second inner end 24B flows out from the second shell end 14B. Here, the exhaust that has passed through the second inner end 24B tries to flow further downstream, so a negative pressure can be created near the second inner end 24B. Furthermore, because the second shell tapered section 11B decreases in diameter as it moves away from the first shell end 14A, a constriction occurs in the exhaust flowing into the downstream exhaust pipe 5. Therefore, the flow velocity of the exhaust flowing into the downstream exhaust pipe 5 increases. As a result, a negative pressure is more likely to occur in the internal space 6. More specifically, a negative pressure is created in the internal space 6 behind the separator 3. For example, a negative pressure is created in the space 63 near the second inner end 24B.
[0043] A negative pressure is generated in the internal space 6, causing air to flow into the internal space 6 (more specifically, the side space 60) from the shell hole 13. This air then flows through the narrow section 61 towards the downstream exhaust pipe 5. Therefore, a flow of air from the atmosphere into the internal space 6 is generated near the shell hole 13, which suppresses exhaust leakage from the internal space 6 into the atmosphere.
[0044] Next, using Figure 2, we will explain the exhaust flow when exhaust flows from downstream to upstream (hereinafter referred to as reverse flow). Reverse flow can be caused, for example, by engine pulsation. The exhaust gas flowing through the downstream exhaust pipe 5 enters the shell member 1 from the second shell end 14B. Then, most of this exhaust gas flows into the inner pipe 2 from the second inner end 24B. Here, since the exhaust gas flows into the inner pipe 2, which has a smaller diameter than the shell member 1, a flow contraction occurs in the exhaust gas flowing into the inner pipe 2. Furthermore, since the diameter of the second inner tapered portion 21B decreases as it moves away from the second inner end 24B, a flow contraction is even more likely to occur in the exhaust gas flowing into the inner central portion 22. As a result, the flow velocity of the exhaust gas flowing into the inner central portion 22 increases. Consequently, a negative pressure is generated in the space surrounded by the inner central portion 22. For example, a negative pressure is generated near the space 65 in front of the inner hole portion 23.
[0045] A portion of the exhaust gas flowing into the shell member 1 from the second shell end 14B flows into the space between the side of the shell member 1 and the side of the inner pipe 2. This exhaust gas flows from downstream to upstream until it hits the separator 3. However, the exhaust gas is obstructed by the separator 3 and does not flow easily upstream of the separator 3. The exhaust gas that remains near the downstream side of the separator 3 flows into the inner central part 22 from the inner hole 23 due to the negative pressure created in the space surrounded by the inner central part 22. More specifically, the exhaust gas hits the separator 3, bends backward, and flows into the inner central part 22 from the inner hole 23. In other words, the exhaust gas is reflected by the separator 3 and flows into the inner central part 22 from the inner hole 23. After that, the exhaust gas flows out from the first shell end 14A and the first inner end 24A into the upstream exhaust pipe 4. The air that flows into the internal space 6 (more specifically, the side space 60) from the shell hole 13 also flows into the space surrounded by the inner central part 22, passing through the narrow part 61 and the inner hole 23.
[0046] [1-3. Effects] According to the first embodiment described in detail above, the following effects can be obtained. (1a) The second inner end 24B of the inner pipe 2 is located in the internal space 6 surrounded by the shell member 1. The side surface of the shell member 1 is provided with a shell hole 13, which is a hole that communicates the internal space 6 with the atmosphere, and the side surface of the inner pipe 2 is provided with an inner hole 23. The shell hole 13 is located on the first shell end 14A side of the inner hole 23. Furthermore, in the side space 60, a narrow section 61 is formed at the first position 61A, which is a space with a relatively smaller cross-sectional area perpendicular to the front-rear direction than the second position 61B.
[0047] Here, when the exhaust passes through the exhaust component 100, air column resonance may occur. However, by providing an expanded space from the inner pipe 2 to the internal space 6, the sound pressure can be released and the pressure reduced, thereby suppressing standing waves. Furthermore, by providing the shell hole 13, the sound pressure can be released and the pressure reduced more effectively. However, on the other hand, it is conceivable that the exhaust may leak to the outside of the exhaust component 100 through the shell hole 13.
[0048] However, with the above-described configuration, in the forward flow, the exhaust gas that has passed through the second inner end 24B tends to flow further downstream, thus creating a negative pressure near the second inner end 24B. This negative pressure in the internal space 6 causes air to flow into the internal space 6 from the shell hole 13. Therefore, a flow of air from the atmosphere into the internal space 6 is generated near the shell hole 13, which suppresses the leakage of exhaust gas from the internal space 6 into the atmosphere.
[0049] Furthermore, during reverse flow, the exhaust gas flowing into the inner pipe 2 undergoes contraction. As a result, negative pressure is generated in the space surrounded by the inner pipe 2. Here, the exhaust gas flowing into the space between the side surface of the shell member 1 and the side surface of the inner pipe 2 flows from downstream to upstream until it hits the separator 3. However, due to the negative pressure generated in the space surrounded by the inner pipe 2 (for example, near space 65), the exhaust gas flows into the inner pipe 2 from the inner hole 23. As a result, the exhaust gas does not easily flow forward of the separator 3 in the space between the side surface of the shell member 1 and the side surface of the inner pipe 2. Consequently, leakage of exhaust gas into the atmosphere from the shell hole 13 located forward of the separator 3 is suppressed.
[0050] In this way, it is possible to suppress exhaust leakage to the outside whether the exhaust flows from upstream to downstream or from downstream to upstream. (1b) The shell member 1 is provided with a second shell tapered portion 11B. In other words, the vicinity of the second shell end 14B is configured such that the cross-sectional area of the cross section perpendicular to the front-rear direction decreases as it moves away from the first shell end 14A. With this configuration, since the diameter of the second shell tapered portion 11B decreases from the upstream side to the downstream side, when flowing forward, a constricted flow is more likely to occur in the exhaust gas flowing into the downstream exhaust pipe 5. Therefore, a negative pressure is more likely to occur in the internal space 6. Consequently, a flow of air from the atmosphere into the internal space 6 is more likely to occur near the shell hole 13, and the leakage of exhaust gas from the internal space 6 into the atmosphere is further suppressed.
[0051] (1c) A separator 3 is provided at the first position 61A of the side space 60. In other words, the separator 3 forms a narrow section 61. With this configuration, when backflow occurs, the separator 3 can block the exhaust gas that flows into the space sandwiched between the side surface of the shell member 1 and the side surface of the inner pipe 2. The exhaust gas is then bent by the separator 3, making it easier for it to flow from the inner hole 23 into the inner pipe 2. In short, by using the separator 3, the flow path of the exhaust gas can be changed with a simple structure.
[0052] (1d) The inner pipe 2 is provided with a second inner tapered portion 21B. In other words, the area near the second inner end 24B is configured such that the cross-sectional area of the cross section perpendicular to the front-rear direction increases as it moves away from the first inner end 24A. With this configuration, since the diameter of the second inner tapered portion 21B decreases from the downstream side to the upstream side, when backflow occurs, the exhaust flowing into the inner central portion 22 is more likely to contract. Therefore, a negative pressure is generated in the space surrounded by the inner central portion 22. Consequently, exhaust flows more easily from the inner hole 23 into the inner pipe 2. Therefore, it is possible to suppress the flow of exhaust towards the shell hole 13 side.
[0053] (1e) The first shell end 14A and the first inner end 24A are provided on the upstream side in the exhaust direction. With this configuration, when flowing forward, exhaust gas flows directly from the upstream exhaust pipe 4 into the inner pipe 2, allowing the exhaust gas to flow smoothly downstream.
[0054] (1f) The shell hole 13 is provided on a part of the side surface of the central part 12 of the shell. With this configuration, even if exhaust gas passes through the narrow part 61 and reaches the shell hole 13 during backflow and leaks to the outside of the exhaust component 100, it will only leak from a part of the side surface of the shell member 1. Therefore, if the location of exhaust gas leakage is fixed and only partial, it becomes easier to take measures such as providing a flow path to guide the leaked exhaust gas.
[0055] [1-4. Correspondence] In the above embodiment, the second shell tapered portion 11B corresponds to the vicinity of the second shell end, and the second inner tapered portion 21B corresponds to the vicinity of the second inner end.
[0056] [2. Second Embodiment] [2-1. Differences from the First Embodiment] The exhaust component 200 of the second embodiment shown in Figure 4 has the same basic configuration as the first embodiment, so the differences will be explained below. Note that the same reference numerals as in the first embodiment indicate the same components, and refer to the preceding description.
[0057] In the first embodiment, the first shell end 14A and the first inner end 24A are provided on the upstream side in the exhaust direction. On the other hand, in the second embodiment, the first shell end 14A and the first inner end 24A are provided on the downstream side in the exhaust direction. In other words, the shell member 1 and inner pipe 2 of the second embodiment are mounted on the vehicle facing opposite directions in the front-rear direction compared to the shell member 1 and inner pipe 2 of the first embodiment.
[0058] [2-1-1. Shell Components] When exhaust flows from the upstream side to the downstream side, the second shell end 14B becomes the exhaust inlet of the exhaust component 200, and the first shell end 14A becomes the exhaust outlet of the exhaust component 200.
[0059] The first shell edge 10A is a substantially cylindrical portion extending forward from the first shell end 14A. The second shell edge 10B is a substantially cylindrical portion extending rearward from the second shell end 14B. The inner circumferential surface of the second shell edge 10B is joined to the outer circumferential surface of the upstream exhaust pipe 4. The shell hole 13 is provided rearward from the separator 3.
[0060] [2-1-2. Inner Pipe] When exhaust gas flows from the upstream side to the downstream side, the second inner end 24B becomes the exhaust gas inlet, and the first inner end 24A becomes the exhaust gas outlet.
[0061] The first inner edge portion 20A is a substantially cylindrical portion extending forward from the first inner end portion 24A. The second inner edge portion 20B is a substantially cylindrical portion extending rearward from the second inner end portion 24B. The inner circumferential surface of the first inner edge portion 20A is joined to the outer circumferential surface of the downstream exhaust pipe 5. The inner hole portion 23 is provided in front of the separator 3. The second inner end portion 24B is located in front of the center of the shell member 1 in the front-rear direction and rearward from the second shell tapered portion 11B.
[0062] [2-1-3. Separator] When the separator 3 is positioned in the side space 60, the separator 3 is arranged such that the first wall portion 31 and the second wall portion 32 protrude forward from the plate portion 30.
[0063] [2-2. Exhaust Flow] The exhaust flow in the second embodiment, when the exhaust flows from the upstream side to the downstream side (i.e., forward flow), will be described.
[0064] The exhaust from the engine, flowing through the upstream exhaust pipe 4, enters the shell member 1 from the second shell end 14B. Then, most of this exhaust flows into the inner pipe 2 from the second inner end 24B. Here, since the exhaust flows into the inner pipe 2, which has a smaller diameter than the shell member 1, a flow contraction occurs in the exhaust flowing into the inner pipe 2. Furthermore, because the diameter of the second inner tapered section 21B decreases as it moves away from the second inner end 24B, a flow contraction is even more likely to occur in the exhaust flowing into the inner central section 22. Therefore, the flow velocity of the exhaust flowing into the inner central section 22 increases. As a result, a negative pressure is created in the space surrounded by the inner central section 22.
[0065] A portion of the exhaust gas that flows into the shell member 1 from the second shell end 14B flows into the space between the side of the shell member 1 and the side of the inner pipe 2. This exhaust gas flows from upstream to downstream until it hits the separator 3. However, the exhaust gas is obstructed by the separator 3 and does not flow easily downstream of the separator 3. The exhaust gas that remains near the upstream side of the separator 3 flows into the inner central part 22 from the inner hole 23 due to the negative pressure generated in the space surrounded by the inner central part 22. After that, the exhaust gas flows out from the first shell end 14A and the first inner end 24A into the downstream exhaust pipe 5.
[0066] Next, we will describe the exhaust flow in the second embodiment when the exhaust flows from the downstream side to the upstream side (i.e., reverse flow). The exhaust gas flowing through the downstream exhaust pipe 5 exits from the first shell end 14A and the first inner end 24A, and the exhaust gas that has passed through the second inner end 24B, which flows into the inner pipe 2, exits from the second shell end 14B. Here, the exhaust gas that has passed through the second inner end 24B tries to flow further upstream, so a negative pressure can be created near the second inner end 24B. Furthermore, since the diameter of the second shell tapered section 11B decreases as it moves away from the first shell end 14A, a contraction occurs in the exhaust gas flowing into the upstream exhaust pipe 4. Therefore, the flow velocity of the exhaust gas flowing into the upstream exhaust pipe 4 increases. As a result, a negative pressure is more easily generated in the internal space 6.
[0067] A negative pressure is generated in the internal space 6, causing air to flow into the internal space 6 from the shell hole 13. This air then flows through the narrow section 61 towards the upstream exhaust pipe 4. Therefore, a flow of air from the atmosphere into the internal space 6 is generated near the shell hole 13, which suppresses exhaust leakage from the internal space 6 into the atmosphere.
[0068] [2-3. Effects] The second embodiment described in detail above also provides the effects (1a) to (1d) and (1f) of the first embodiment. In the effects of the first embodiment, the term "forward flow" is used, and in the effects of the second embodiment, the term "reverse flow" is used.
[0069] [3. Other Embodiments] While embodiments of this disclosure have been described above, it goes without saying that this disclosure is not limited to the embodiments described above and can take various forms.
[0070] (3a) In the above embodiment, a configuration in which the narrowed portion 61 is formed by the separator 3 is illustrated. However, the exhaust component does not have to be equipped with the separator 3. For example, as shown in the exhaust component 300 of the modified example 1 in Figure 5, the shell member 1 may have a reduced diameter shape at the first position 61A. More specifically, the shell member 1 may have a reduced diameter shape at the first position 61A as it moves from the second shell end 14B toward the first shell end 14A. In other words, a step 303 may be provided at the first position 61A, and the narrowed portion 61 may be formed by the step 303. For example, the reduced diameter shape may be formed at the first position 61A by spinning.
[0071] In the modified example 1, the side space 60 from the shell hole 13 to the first position 61A has a narrower exhaust flow path than the side space 60 from the first position 61A to the inner hole 23. Therefore, the exhaust flowing from the second shell end 14B toward the first shell end 14A into the space between the side surface of the shell member 1 and the side surface of the inner pipe 2 is blocked by the step 303 at the first position 61A, making it difficult for it to flow further toward the first shell end 14A. As a result, it becomes difficult for the exhaust to reach the shell hole 13, thus suppressing the leakage of exhaust from the shell hole 13 to the outside of the exhaust component 300.
[0072] (3b) In the above embodiment, a configuration comprising one separator 3 was illustrated. However, the exhaust component may comprise multiple separators 3. The multiple separators 3 may be arranged in a line in the side space 60 with a predetermined interval between them in the front-rear direction.
[0073] Furthermore, as shown in the exhaust component 400 of the modified example 2 in Figure 6A, for example, in addition to the separator 3 for forming the narrow portion 61, a separator 403 for supporting the inner pipe 2 may also be provided. The separator 403 is a plate-shaped member having an annular shape. The separator 403 is provided with a through hole that penetrates in the thickness direction of the separator 403.
[0074] The inner pipe 2 is inserted into a circular hole formed by the separator 403. The outer edge of the separator 403 abuts against the inner surface of the shell member 1, and the inner edge of the separator 403 abuts against the outer surface of the inner pipe 2. The exhaust can move through the through-hole of the separator 403 within the internal space 6. The separator 403 allows the inner pipe 2 to be firmly fixed in place.
[0075] Furthermore, as shown in the exhaust component 500 of modified example 3 in Figure 6B, for example, in addition to the separator 3 for forming the narrow section 61, a separator 503 may be provided for dividing the internal space 6 into multiple chambers. The separator 503 is a plate-shaped member having a circular shape. The separator 503 is provided with through holes that penetrate in the thickness direction of the separator 503.
[0076] For example, the separator 503 may be provided between the second inner end 24B and the second shell end 14B. The outer edge of the separator 503 abuts against the inner surface of the shell member 1. The exhaust air can move through the through-hole of the separator 503 within the internal space 6. By dividing the internal space 6 into multiple chambers, resonance can be suppressed and a sound-dampening effect can be achieved.
[0077] (3c) In the above embodiment, a configuration in which the vicinity of the first shell end 14A and the vicinity of the second shell end 14B have a reduced diameter was illustrated. However, the shape of the vicinity of the first shell end 14A and the vicinity of the second shell end 14B is not limited to this. For example, as shown in Modification 4 of Figure 7, the exhaust component 600 may include a first lid portion 601 and a second lid portion 602. Also, the shell member 1 does not have to include a first shell tapered portion 11A and a second shell tapered portion 11B, or a first shell edge portion 10A and a second shell edge portion 10B. In other words, the shell member 1 does not have to have a reduced diameter at both ends. Also, the shell member 1 may have a reduced diameter at only one end.
[0078] The first lid portion 601 is a lid that closes the first shell end portion 14A. The first lid portion 601 may have a curved shape that is recessed forward, or it may have a plate-like shape. The first lid portion 601 and the first shell end portion 14A may be joined by, for example, welding. Alternatively, the first lid portion 601 and the first shell end portion 14A may be joined by, for example, bending the edge of the first lid portion 601 so as to wrap around the first shell end portion 14A and crimping the wrapped portion.
[0079] The second cover portion 602 is a cover that closes the second shell end portion 14B. The second cover portion 602 may have a curved shape that is recessed to the rear, or it may have a plate-like shape. The inner pipe 2 is inserted so as to pass through the first lid portion 601. With a structure that includes the first lid portion 601 and the second lid portion 602, both ends of the shell member 1 can be closed with a simple configuration.
[0080] (3d) In the above embodiment, an example was given in which the inner pipe 2 includes a second inner tapered portion 21B and a second inner edge portion 20B. However, the shape of the inner pipe 2 is not limited to this. For example, the inner pipe 2 may have a shape that does not include the second inner edge portion 20B. Also, for example, the inner pipe 2 may have a shape that does not include the second inner tapered portion 21B and the second inner edge portion 20B.
[0081] (3e) In the above embodiment, an example was given in which the shell holes 13 are provided on a part of the side surface of the central shell portion 12. However, the position in which the shell holes 13 are provided is not limited to this. For example, the shell holes 13 may be provided on the side surface of the central shell portion 12 in a circumferential direction. The shell holes 13 may be provided on the side of the first shell end portion 14A that is closer to the separator 3.
[0082] Furthermore, for example, if the shell hole 13 is located at the bottom when the exhaust component 100 is mounted on the vehicle, condensed water can be drained from the shell hole 13. (3f) In the above embodiment, an example was given in which the inner holes 23 are provided in a circumferential arrangement on the side surface of the inner central portion 22. However, the position in which the inner holes 23 are provided is not limited to this. For example, the inner holes 23 may be provided on a part of the side surface of the inner central portion 22. Also, for example, the inner holes 23 may be provided in a front-to-back direction in addition to the circumferential direction. The inner holes 23 only need to be provided on the side of the second inner end portion 24B that is closer to the separator 3.
[0083] (3g) In the above embodiment, a configuration in which the shell member 1 and the inner pipe 2 are substantially cylindrical pipes was illustrated. However, the shape of the shell member 1 and the inner pipe 2 is not limited to this. For example, the shell member 1 and / or the inner pipe 2 may have a cross-section perpendicular to the front-rear direction that is substantially elliptical or substantially polygonal.
[0084] (3h) The functions of one component in the above embodiment may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, some parts of the configuration of the above embodiment may be omitted. Also, at least some parts of the configuration of the above embodiment may be added to, replaced with, etc., the configuration of other above embodiments.
[0085] [Technical concepts disclosed in this specification] [Item 1] It is an exhaust component, A component that forms an exhaust flow path, comprising a tubular shell member and an inner pipe, The inner pipe penetrates the first shell end, which is one end of the shell member, and is inserted into the shell member along the extension direction, which is the direction in which the shell member extends. The first inner end, which is one end of the inner pipe, is connected to the outside of the shell member. The second inner end of the inner pipe, which is the end opposite to the first inner end, is located in the internal space surrounded by the shell member. The side surface of the shell member is provided with a shell hole portion, which is a hole through which the internal space and the atmosphere communicate. The inner pipe is provided with an inner hole portion, which is a hole, on its side surface. The shell hole portion is provided on the first shell end side of the inner hole portion, An exhaust component in which, in the internal space, a space formed between the side surface of the shell member and the side surface of the inner pipe, a narrow portion is formed at a first position in the side space which is the space between the shell hole and the inner hole, and the cross-sectional area of the cross-section perpendicular to the extension direction is relatively smaller than that of a second position which is any position in the side space other than the first position.
[0086] [Item 2] Exhaust components as described in item 1, An exhaust component wherein the vicinity of the second shell end, which is the end of the shell member opposite to the first shell end, is configured such that the cross-sectional area of the section perpendicular to the extension direction decreases as it moves away from the first shell end.
[0087] [Item 3] Exhaust components as described in item 1 or item 2, A separator is provided at the first position of the side space, which is a member having a surface that extends in a direction intersecting the extension direction. An exhaust component in which the narrow portion is formed by the separator.
[0088] [Item 4] Exhaust components as described in any one of items 1 through 3, An exhaust component wherein the vicinity of the second inner end of the inner pipe has a portion configured such that the cross-sectional area of the cross-section perpendicular to the extension direction increases as it moves away from the first inner end.
[0089] [Item 5] Exhaust components as described in any one of items 1 through 4, The exhaust component in question is installed in the vehicle. The first shell end and the first inner end are exhaust components provided on the upstream side in the exhaust direction, which is the direction in which exhaust gas flows from the engine. [Explanation of Symbols]
[0090] 1...Shell member, 2...Inner pipe, 3, 403, 503...Separator, 4...Upstream exhaust pipe, 5...Downstream exhaust pipe, 6...Internal space, 10A...First shell edge, 10B...Second shell edge, 11A...First shell tapered section, 11B...Second shell tapered section, 12...Shell center, 13...Shell hole, 14A...First shell end, 14B...Second shell end, 20A...First inner edge, 20B...Second inner Edge, 21A...First inner tapered section, 21B...Second inner tapered section, 22...Inner central section, 23...Inner hole section, 24A...First inner end, 24B...Second inner end, 30...Plate section, 31...First wall section, 32...Second wall section, 60...Side space, 61...Narrow section, 63, 65...Space, 100, 200, 300, 400, 500, 600...Exhaust parts, 303...Step, 601...First cover section, 602...Second cover section.
Claims
1. It is an exhaust component, A component that forms an exhaust flow path, comprising a tubular shell member and an inner pipe, The inner pipe penetrates the first shell end, which is one end of the shell member, and is inserted into the shell member along the extension direction, which is the direction in which the shell member extends. The first inner end, which is one end of the inner pipe, is connected to the outside of the shell member. The second inner end of the inner pipe, which is the end opposite to the first inner end, is located in the internal space surrounded by the shell member. The side surface of the shell member is provided with a shell hole portion, which is a hole through which the internal space and the atmosphere communicate. The inner pipe is provided with an inner hole portion, which is a hole, on its side surface. The shell hole portion is provided on the first shell end side of the inner hole portion. An exhaust component in which, in the internal space, a space formed between the side surface of the shell member and the side surface of the inner pipe, a narrow portion is formed at a first position in the side space which is the space between the shell hole and the inner hole, and the cross-sectional area of the cross-section perpendicular to the extension direction is relatively smaller than that of a second position which is any position in the side space other than the first position.
2. An exhaust component according to claim 1, An exhaust component wherein the vicinity of the second shell end, which is the end of the shell member opposite to the first shell end, is configured such that the cross-sectional area of the section perpendicular to the extension direction decreases as it moves away from the first shell end.
3. An exhaust component according to claim 1 or claim 2, A separator is provided at the first position of the side space, which is a member having a surface that extends in a direction intersecting the extension direction. An exhaust component in which the narrow portion is formed by the separator.
4. An exhaust component according to claim 1 or claim 2, An exhaust component wherein the vicinity of the second inner end of the inner pipe has a portion configured such that the cross-sectional area of the cross section perpendicular to the extension direction increases as it moves away from the first inner end.
5. An exhaust component according to claim 1 or claim 2, The exhaust component is installed in the vehicle. The first shell end and the first inner end are exhaust components provided on the upstream side in the exhaust direction, which is the direction in which exhaust gas flows from the engine.