JP7469279B2 - Exhaust Parts - Google Patents

Description

This disclosure relates to exhaust components.

Patent Document 1 discloses a manifold converter that includes a cylindrical container that houses a catalyst, an upstream diffuser that is welded to the upper opening of the cylindrical container and connected to an exhaust manifold, and a downstream diffuser that is welded to the lower opening of the cylindrical container. A reinforcing flange that is bent inward is integrally formed around the entire circumference of the lower opening of the upstream diffuser to increase the rigidity of the upstream diffuser and prevent deformation of the lower opening due to the heat of exhaust gas.

Japanese Utility Model Application Publication No. 5-38316

The manifold converter described above undergoes thermal expansion along the direction of exhaust gas flow. Since the manifold converter is fastened to another member, this thermal expansion is restricted, and as a result, thermal stress is applied to the manifold converter. This thermal stress can cause damage to the upstream diffuser, which has weak parts, such as parts that are smaller in diameter than the surrounding parts or parts with low rigidity.

One aspect of the present disclosure aims to provide a technology that suppresses damage to exhaust components due to thermal stress caused by thermal expansion along the flow direction of exhaust gas.

One aspect of the present disclosure is an exhaust part that forms an exhaust flow path that guides exhaust gas from an internal combustion engine, and includes an exhaust manifold, a catalyst case, and an intermediate part. The exhaust manifold has a flange in which at least one through hole is formed that functions as an inlet through which exhaust gas from the internal combustion engine flows, and at least one exhaust pipe into which exhaust gas that has passed through the at least one through hole flows. The catalyst case is disposed downstream of the exhaust manifold and has a cylindrical part that houses a catalyst that purifies the exhaust gas. The intermediate part is a part that is located downstream of at least one exhaust pipe and upstream of the cylindrical part in the exhaust part, and the cross-sectional area of the part perpendicular to the flow direction of the exhaust gas expands toward the downstream side. In addition, the intermediate part has a bending part with multiple bending points where the curvature changes in a wall part that forms the intermediate part.

In this configuration, a bent portion is provided in the middle portion, which is considered to be easily damaged by thermal stress caused by thermal expansion of the exhaust part along the exhaust gas flow direction. Therefore, even if the thermal stress is applied to the middle portion, the thermal stress is likely to be dispersed at the multiple bending points of the bent portion. Therefore, it is possible to suppress damage to the exhaust part due to thermal stress caused by thermal expansion along the exhaust gas flow direction.

In one aspect of the present disclosure, the bent portion may be a recess in which a portion of the wall is recessed inward. In such a configuration, the recess provided in the middle portion can suppress damage to the exhaust part due to thermal stress. Note that when a recess is provided in the upstream portion of the middle portion, which is a portion with a relatively small cross-sectional area, it is particularly effective in mitigating thermal stress on the middle portion.

In one aspect of the present disclosure, the flange may be a plate-like member. The at least one through hole may be a plurality of through holes. The arrangement direction of the plurality of through holes may be the longitudinal direction of the flange. When the exhaust part is projected onto a first imaginary plane along the plane in which the plurality of through holes of the flange are formed, the central axis of the tubular part is positioned offset from a first center line that is a line passing through the longitudinal center of the flange and perpendicular to the longitudinal direction, the bent part may be located in a range on the first center line side in the intermediate part.

In such a configuration, the central axis of the tubular portion is positioned offset from the first center line in the first imaginary plane. In such a case, thermal stress caused by the thermal expansion is likely to be applied to the area of the intermediate portion on the first center line side. Therefore, in a configuration in which a tubular portion is positioned as described above, by positioning the bent portion in the area of the intermediate portion on the first center line side where thermal stress is likely to be applied, the thermal stress applied to the intermediate portion can be alleviated.

In one aspect of the present disclosure, the flange may be a plate-like member. At least one through hole may be a plurality of through holes. The direction perpendicular to the longitudinal direction of the flange, which is the arrangement direction of the plurality of through holes, and along the plane in which the plurality of through holes of the flange are formed may be the short-side direction of the flange. The bent portion may be located in the range on the flange side of the intermediate portion when the central axis of the tubular portion is inclined with respect to the second center line, which is a line passing through the center of the short-side direction of the flange and is a line perpendicular to the short-side direction, when the exhaust part is projected onto a second imaginary plane, which is a plane perpendicular to a first imaginary plane along the plane in which the plurality of through holes of the flange are formed and is along the short-side direction.

In this configuration, the central axis of the tubular portion is inclined relative to the second center line in the second imaginary plane. In this case, thermal stress caused by the thermal expansion is likely to be applied to the flange side area of the intermediate portion. Therefore, in the configuration in which the tubular portion is disposed as described above, by positioning the bent portion in the flange side area of the intermediate portion where thermal stress is likely to be applied, the thermal stress applied to the intermediate portion can be alleviated.

In one aspect of the present disclosure, the flange may be a plate-like member. At least one through hole may be a plurality of through holes. The arrangement direction along the plurality of through holes may be the longitudinal direction of the flange. The direction perpendicular to the longitudinal direction and along the plane in which the plurality of through holes of the flange are formed may be the transverse direction of the flange. The bent portion may be located in a range on the first center line side of the intermediate portion and in a range on the flange side of the intermediate portion when the exhaust part is projected on a first imaginary plane along the plane in which the plurality of through holes of the flange are formed, the central axis of the cylindrical part is in a state in which it is arranged offset from a first center line that is a line passing through the center of the longitudinal direction of the flange and is a line perpendicular to the longitudinal direction, and when the exhaust part is projected on a second imaginary plane that is a plane perpendicular to the first imaginary plane and along the transverse direction, the central axis of the cylindrical part is in a state in which it is arranged inclined with respect to a second center line that is a line passing through the center of the transverse direction of the flange and is a line perpendicular to the transverse direction.

In such a configuration, the central axis of the tubular portion is positioned offset from the first center line in the first imaginary plane, and the central axis of the tubular portion is positioned inclined relative to the second center line in the second imaginary plane. In such a case, thermal stress caused by thermal expansion along the exhaust gas flow direction of the exhaust part is likely to be applied to the range on the first center line side and the flange side of the intermediate portion. Therefore, in a configuration in which a tubular portion is disposed as described above, by positioning the bent portion in the range on the first center line side and the flange side of the intermediate portion where thermal stress is likely to be applied, the thermal stress applied to the intermediate portion can be alleviated.

In one aspect of the present disclosure, the bent portion may have a length in a direction along the circumferential direction of the intermediate portion. In such a configuration, the bent portion extends along the circumferential direction of the intermediate portion. Therefore, compared to a configuration in which the bent portion extends along the flow direction of the exhaust gas, the bent portion can distribute the stress applied to the intermediate portion while also making it easier to maintain the rigidity of the intermediate portion around the portion where the bent portion is provided.

FIG. FIG. FIG. 4 is a perspective view showing the exhaust part as viewed from the rear side. FIG. 2 is a top view of the exhaust components with a portion of the exhaust manifold shown in transparent form. FIG. 4 is a top view showing the upstream cone. FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5 . Fig. 7A is a diagram showing a modified catalyst case, Fig. 7B is a diagram showing a modified exhaust manifold, Fig. 7C is a diagram showing another modified exhaust manifold, and Fig. 7D is a diagram showing yet another modified exhaust manifold. Fig. 8A is a diagram showing a first arrangement state of exhaust components of this embodiment. Fig. 8B is a diagram showing a second arrangement state of exhaust components of this embodiment. Fig. 8C is a diagram showing a modified arrangement state of exhaust components. Fig. 8D is a diagram showing another modified arrangement state of exhaust components. Fig. 8E is a diagram showing yet another modified arrangement state of exhaust components. 9A and 9B are schematic diagrams showing an exhaust component with two catalyst cases arranged parallel to each other, and FIG. 9B is a schematic diagram showing an exhaust component with two catalyst cases arranged perpendicular to each other. FIG. 13 is a diagram showing a configuration in which two bent portions are provided in parallel to each other on the upstream cone. 11 is a cross-sectional view taken along the line XI-XI of FIG. 13 is a diagram showing a configuration in which two bent portions are provided side by side at a circumferential interval on an upstream cone. FIG.

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.
[1. Configuration]
[1-1. overall structure]
1 to 4 forms a part of an exhaust flow passage for guiding exhaust gas discharged from each of a plurality of cylinders (for example, four cylinders) of an internal combustion engine of a vehicle to the outside of the vehicle. The exhaust part 100 includes an upstream flange 1, an exhaust manifold 2, an upstream cone 3, a catalyst case 4, a downstream cone 5, a tubular member 6, and a downstream flange 7.

The upstream flange 1 is a plate-shaped metal member. A portion of the upstream flange 1 is fixed to the internal combustion engine of the vehicle. As shown in FIG. 3, the upstream flange 1 has a plurality of through holes, for example, four through holes 11-14, which function as inlets through which exhaust gas from each cylinder of the internal combustion engine flows in. The upstream flange 1 has a length in the arrangement direction of the four through holes 11-14. As shown in FIG. 1, the upstream ends of four exhaust pipes 21-24, which will be described later, are connected to each of the through holes 11-14.

In the following description, the arrangement direction of the four through holes 11-14 is defined as the longitudinal direction of the upstream flange 1, and the direction perpendicular to the longitudinal direction and along the flange plane 15 on which the four through holes 11-14 of the upstream flange 1 are formed is defined as the lateral direction of the upstream flange 1. The plane along the flange plane 15 is defined as the first imaginary plane P1 shown in FIG. 1, and the plane perpendicular to the first imaginary plane P1 and along the lateral direction is defined as the second imaginary plane P2 shown in FIG. 2. The exhaust gas flowing through the exhaust part 100 flows into the upstream flange 1 as indicated by the arrow "G" shown in FIG. 2.

The exhaust manifold 2 is a metal member, and is connected to the upstream flange 1 as shown in FIG. 1. In this embodiment, the exhaust manifold 2 forms an exhaust flow path that merges the exhaust gas flowing out from each cylinder of the internal combustion engine so that four exhaust flow paths corresponding to the four cylinders are consolidated into one exhaust flow path. The exhaust manifold 2 has four exhaust pipes 21-24 and a junction section 25. Exhaust gas that has passed through the four through holes 11-14 flows into each of the exhaust pipes 21-24. The junction section 25 is an exhaust pipe that forms an exhaust flow path for merging the exhaust gas flowing out from the four exhaust pipes 21-24.

The upstream cone 3 is located downstream of the exhaust manifold 2 and upstream of the catalyst case 4 described later, and connects the exhaust manifold 2 and the catalyst case 4. Specifically, the upstream cone 3 is a metal member and is connected to the downstream end of the junction 25 of the exhaust manifold 2. The upstream cone 3 is cylindrical and has a tapered shape in which the diameter of the exhaust flow path increases toward the downstream side. In other words, the cross-sectional area of the upstream cone 3 perpendicular to the flow direction of the exhaust gas increases toward the downstream side. The upstream cone 3 may be formed into a cylindrical shape by butting and joining two parts divided along the flow direction of the exhaust gas. The upstream cone 3 forms an exhaust flow path for the exhaust gas flowing out from the junction 25. As shown in Figures 3 to 6, the upstream cone 3 has a bending portion 32 having multiple bending points 321, which are points where the curvature changes suddenly, in the wall portion 31 that forms the upstream cone 3. The point where the curvature changes suddenly is the point where the upstream cone 3 suddenly bends from a straight line, i.e., a state where the curvature is zero, to a certain curvature or more. In other words, the bent portion 32 is a bent portion provided on the upstream cone 3, separate from the shape required to guide the flow direction of the exhaust gas in the upstream cone 3. In other words, the bent portion 32 is not provided on the upstream cone 3 primarily for the purpose of guiding the flow direction of the exhaust gas.

6, the bending portion 32 is a recessed portion having a shape in which a part of the wall portion 31 is recessed inward. The bending portion 32 may be a convex portion having a shape in which a part of the wall portion 31 protrudes outward. That is, the bending portion 32 having multiple bending points 321 is a recessed portion or a convex portion. As shown in FIG. 5, the bending portion 32 is a recessed portion extending along the circumferential direction of the upstream cone 3. In other words, the multiple bending points 321 included in the bending portion 32 have a length in a direction along the circumferential direction of the upstream cone 3. The bending portion 32 has a length of about 1/4 of the total circumference of the upstream cone 3 in the circumferential direction. The bending portion 32 is provided in a predetermined range in the upstream cone 3. The predetermined range is a range determined based on the arrangement of the catalyst case 4 relative to the upstream flange 1 in the upstream cone 3, and is a range in which the section modulus of the upstream cone 3 is small. The section modulus represents resistance to stress that bends the cross section. The specified range in which the bending portion 32 is provided will be described in detail later.

The catalyst case 4 is a metal member, and is connected to the downstream end of the upstream cone 3 as shown in Figures 1 to 3. The catalyst case 4 has a cylindrical shape. The catalyst case 4 houses a cylindrical catalyst (not shown) inside for purifying exhaust gas.

The downstream cone 5 is a metal member that is connected to the downstream end of the catalyst case 4. The downstream cone 5 is cylindrical and has a tapered shape in which the diameter of the exhaust flow path becomes smaller toward the downstream side. The downstream cone 5 may be formed into a cylindrical shape by butting together two parts that are divided along the flow direction of the exhaust gas. The downstream cone 5 forms the exhaust flow path for the exhaust gas purified by the catalyst.

The tubular member 6 is a metal member that is connected to the downstream end of the downstream cone 5. The tubular member 6 has a cylindrical shape. The tubular member 6 forms an exhaust flow path for the exhaust gas that flows out from the downstream cone 5.

The downstream flange 7 is a plate-shaped metal member. The downstream flange 7 has a through hole through which the tubular member 6 can be inserted, and is fixed to the tubular member 6 that passes through the through hole. A portion of the downstream flange 7 is fixed to the internal combustion engine.

[1-2. Catalyst case arrangement and bent portion position]
In this embodiment, the catalyst case 4 is disposed as described below with respect to the upstream flange 1 of the exhaust part 100. Furthermore, with respect to the disposition of the catalyst case 4, the bent portion 32 is located in a predetermined range of the upstream cone 3, which will be described below.

As shown in FIG. 1, when the exhaust part 100 is projected onto a first imaginary plane P1, the catalyst case 4 is in a first arrangement state in which the central axis A of the catalyst case 4 is arranged offset from the first center line B1. The first center line B1 is a line that passes through the longitudinal center of the upstream flange 1 and is a line perpendicular to the longitudinal direction. The state in which the central axis A is arranged offset from the first center line B1 includes a state in which the central axis A is arranged parallel to and spaced apart from the first center line B1, and a state in which the central axis A is arranged at an angle to the first center line B1. In this embodiment, the catalyst case 4 is in a state in which the central axis A is arranged parallel to and spaced apart from the first center line B1.

As shown in FIG. 2, when the exhaust part 100 is projected onto the second imaginary plane P2, the catalyst case 4 is in a second arrangement state in which the central axis A of the catalyst case 4 is inclined with respect to the second center line B2. The second center line B2 is a line that passes through the center of the upstream flange 1 in the short direction and is perpendicular to the short direction. In this embodiment, the catalyst case 4 is arranged such that the central axis A intersects with the second center line B2 at an angle slightly larger than a right angle, and is further away from the first imaginary plane P1 as it moves downstream.

As described above, the catalyst case 4 is arranged in the first arrangement state and the second arrangement state. Therefore, as shown in FIG. 4, the predetermined range in the upstream cone 3 is the overlapping range of the first range C1 on the first center line B1 side of the upstream cone 3 and the second range C2 on the upstream flange 1 side of the upstream cone 3. The bent portion 32 is located in that range.

Specifically, the first range C1 in the upstream cone 3 is the range on the first center line B1 side when the upstream cone 3 is divided along a line parallel to the second center line B2 in a state in which the exhaust part 100 is viewed from the upstream side as shown in FIG. 4. In other words, the first range C1 in the upstream cone 3 is the range of the left half of the upstream cone 3 when the upstream cone 3 is divided in half in the left-right direction when the top to bottom of the page is defined as the up-down direction and the left to right of the page is defined as the left-right direction in a top-down view of the upstream cone 3 shown in FIG. 5.

In this embodiment, the exhaust part 100 is fastened to other members by the upstream flange 1 and the downstream flange 7. Therefore, as shown in FIG. 1, when the catalyst case 4 is in the first arrangement state, if the thermal expansion of the exhaust part 100 along the exhaust gas flow direction is restricted by the fastening, the exhaust part 100 is likely to bend due to the application of a load in the direction of compression shown by the arrow in FIG. 1. In other words, when the central axis A of the catalyst case 4 is arranged offset from the first center line B1 with respect to the longitudinal direction of the upstream flange 1 in the first imaginary plane P1, the reaction force F1 on the side of the upstream flange 1 whose length from the central axis A is L1 is smaller than the reaction force F2 on the side of the upstream flange 1 whose length from the central axis A is L2, as shown in FIG. The reaction force here refers to the force that the upstream flange 1 receives from the internal combustion engine in the opposite direction to the force that the upstream flange 1 applies to the internal combustion engine due to the thermal expansion of the exhaust part 100 along the exhaust gas flow direction. Therefore, when a load is applied to the side of the upstream flange 1 that is a length L1 from the central axis A so that the exhaust manifold 2 and the catalyst case 4 approach each other, the exhaust part 100 is likely to bend so that the portion between the exhaust manifold 2 and the catalyst case 4 is bent. When the exhaust part 100 is bent in this way, thermal stress is likely to be applied to the first range C1 of the upstream cone 3, which is generated by limiting thermal elongation along the flow direction of the exhaust gas.

The second range C2 in the upstream cone 3 is the range on the upstream flange 1 side when the upstream cone 3 is divided along a line parallel to the first imaginary plane P1 when the exhaust part 100 is viewed from the upstream side as shown in FIG. 4. In other words, the second range C2 in the upstream cone 3 is the range of the upper half of the upstream cone 3 when the upstream cone 3 is divided in half vertically when the top to bottom of the page is defined as the vertical direction and the left to right of the page is defined as the horizontal direction when viewed from above the upstream cone 3 as shown in FIG. 5.

As described above, the exhaust part 100 is fastened to other members by the upstream flange 1 and the downstream flange 7. Therefore, as shown in FIG. 2, when the catalyst case 4 is in the second arrangement state, if the thermal expansion of the exhaust part 100 along the exhaust gas flow direction is suppressed by this fastening, the exhaust part 100 is likely to bend due to the application of a load in the compression direction shown by the arrow in FIG. 2. When the exhaust part 100 bends in this way, thermal stress caused by the suppression of thermal expansion along the exhaust gas flow direction is likely to be applied to the second range C2 in the upstream cone 3.

In other words, the first range C1 and the second range C2 described above are weak parts of the upstream cone 3 that are considered to be easily damaged by thermal stress generated by restricting thermal expansion along the exhaust gas flow direction when the catalyst case 4 is in the first arrangement state and the second arrangement state. In other words, the first range C1 and the second range C2 in the upstream cone 3 are ranges that are easily subjected to thermal stress generated by restricting thermal expansion along the exhaust gas flow direction in the exhaust part 100, which is determined based on the arrangement of the catalyst case 4 relative to the upstream flange 1. In other words, the first range C1 and the second range C2 in the upstream cone 3 are ranges in which the section modulus of the upstream cone 3 is small.

3. Effects
According to the embodiment described above in detail, the following effects can be obtained.
(3a) In this embodiment, the bent portion 32 having a plurality of bent points 321 is provided in the upstream cone 3 having a portion that is narrower in diameter than the catalyst case 4. Therefore, even if the thermal expansion of the exhaust part 100 along the exhaust gas flow direction is restricted by the exhaust part 100 being fastened to another member by the upstream flange 1 and the downstream flange 7, and the thermal stress is applied to the upstream cone 3, the thermal stress is easily dispersed at the plurality of bent points 321 of the bent portion 32. Therefore, it is possible to suppress damage to the upstream cone 3 of the exhaust part 100 due to the thermal stress generated due to the thermal expansion along the exhaust gas flow direction.

(3b) In this embodiment, when the exhaust part 100 is projected onto the first imaginary plane P1, the catalyst case 4 is in a first arrangement state in which the central axis A is arranged offset from the first center line B1 on the first imaginary plane P1, and when the exhaust part 100 is projected onto the second imaginary plane P2, the catalyst case 4 is in a second arrangement state in which the central axis A is arranged inclined relative to the second center line B2 on the second imaginary plane P2. Therefore, the thermal stress caused by the thermal expansion of the exhaust part 100 along the exhaust gas flow direction is likely to be applied to the first range C1 and the second range C2 of the upstream cone 3. Therefore, in the configuration in which the catalyst case 4 is arranged as described above, the bending portion 32 is located in the overlapping range of the first range C1 and the second range C2 of the upstream cone 3, which is the range in which thermal stress is likely to be applied, and the thermal stress applied to the upstream cone 3 can be alleviated.

(3c) In this embodiment, the bent portion 32 is a recess in which part of the wall portion 31 is recessed inward. The recess provided in the upstream cone 3 can suppress damage to the exhaust part 100 due to thermal stress. Note that when a recess is provided in the upstream portion of the upstream cone 3, which is a portion of the upstream cone 3 with a relatively small cross-sectional area, it is particularly effective in alleviating the thermal stress applied to the upstream cone 3.

(3d) In the present embodiment, the bent portion 32 extends along the circumferential direction of the catalyst case 4. Therefore, compared to a configuration in which the bent portion extends along the flow direction of the exhaust gas, the bent portion 32 can disperse the stress applied to the upstream cone 3, while making it easier to maintain the rigidity of the upstream cone 3 around the portion where the bent portion 32 is provided.
The upstream flange 1 corresponds to a flange, and the upstream cone 3 corresponds to an intermediate portion. In this embodiment, the entire catalyst case 4 is a cylindrical portion.

4. Other embodiments
Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take various forms.

(4a) In the above embodiment, four through holes 11 to 14 are provided, and the upstream flange 1 has a length in the arrangement direction along the four through holes 11 to 14. However, the shape of the upstream flange and the number of through holes provided in the upstream flange are not limited to this. For example, the number of through holes may be five or more or three or less.

(4b) In the above embodiment, the exhaust part 100 includes an exhaust manifold 2 having four exhaust pipes 21-24, an upstream cone 3, and a catalyst case 4, but the configuration of the exhaust part 100 is not limited to this. Although not shown, the exhaust parts 100a-100d in Figures 7A-7D shown below also have bent portions 32 in a predetermined range that is considered to be easily damaged by thermal stress caused by thermal expansion along the flow direction of the exhaust gas.

For example, as shown in FIG. 7A, the exhaust part 100a may have an upstream flange 1a, an exhaust manifold 2a, and a catalyst case 4a. The upstream flange 1a has three through holes. The exhaust manifold 2a has three exhaust pipes that connect to the three through holes in the upstream flange 1a, and forms an exhaust flow path that merges exhaust gases flowing from the three exhaust pipes. The catalyst case 4a has a shape such that the upstream end that connects to the exhaust manifold 2a narrows toward the upstream side. In other words, in a configuration that does not have an upstream cone 3, the catalyst case 4a may have a portion that has a shape corresponding to the upstream cone 3 of this embodiment.

For example, the exhaust part 100b shown in FIG. 7B may be configured to include an upstream flange 1b, an exhaust manifold 2b, an upstream cone 3, and a catalyst case 4. The upstream flange 1b is provided with a through hole capable of collecting exhaust gas from multiple cylinders of the internal combustion engine. The exhaust manifold 2b is formed by one exhaust pipe connected to the through hole provided in the upstream flange 1b. The exhaust manifold 2b may be formed by butting two parts that are divided along the flow direction of the exhaust gas together and joining them. In other words, the exhaust manifold 2b may be formed into a cylindrical shape by butting two parts that have a U-shaped cross section perpendicular to the flow direction of the exhaust gas together.

Also, for example, as in the exhaust part 100c shown in FIG. 7C, it may be configured to include an upstream flange 1b, an exhaust manifold 2c, and a catalyst case 4. The exhaust manifold 2c is an exhaust pipe that connects to a through hole provided in the upstream flange 1b, and has a shape in which the downstream end connected to the catalyst case 4 expands in diameter toward the downstream side. In other words, in a configuration that does not have an upstream cone 3, the exhaust manifold 2c may have a part with a shape corresponding to the upstream cone 3 of this embodiment. The exhaust manifold 2c may have a monaka structure formed by butting together two parts that are divided along the flow direction of the exhaust gas.

In addition, an exhaust manifold 2d, which is a single exhaust pipe connected to a single through hole provided in an upstream flange 1b and has a shape in which the downstream end connected to the catalyst case 4 expands in diameter toward the downstream side, such as exhaust part 100d shown in FIG. 7D, may be formed so that the direction of division of the two parts divided along the flow direction of the exhaust gas is different from that of the exhaust manifold 2c shown in FIG. 7C.

(4c) In the above embodiment, the catalyst case 4 and the upstream flange 1 are shown in the first arrangement state shown in the schematic diagram of FIG. 8A and in the second arrangement state shown in the schematic diagram of FIG. 8B, and the exhaust part 100 is shown in a state in which the exhaust part is mounted on the vehicle. However, the state in which the exhaust part is mounted on the vehicle is not limited to this. Although not shown, the exhaust parts 100e to 100g in FIGS. 8C to 8E shown below also have a bent portion 32 in a predetermined range that is considered to be easily damaged by thermal stress caused by thermal expansion along the flow direction of the exhaust gas.

For example, the catalyst case 4 may be in either the first arrangement state or the second arrangement state.
Also, for example, like the state of the exhaust part 100e mounted on the vehicle shown in the schematic diagram of Fig. 8C, the catalyst case 4 may be in an arrangement state in which the central axis A of the catalyst case 4 is not displaced from the first center line B1 in the first imaginary plane P1, and in the second arrangement state shown in the schematic diagram of Fig. 8B. In other words, the catalyst case 4 may be in an arrangement state in which the central axis A of the catalyst case 4 coincides with the first center line B1 in the first imaginary plane P1, and in the second arrangement state shown in the schematic diagram of Fig. 8B.

Also, for example, as shown in the schematic diagram of FIG. 8D when exhaust part 100f is mounted on a vehicle, catalyst case 4 may be arranged such that central axis A of catalyst case 4 passes through the longitudinal center of upstream flange 1 on first imaginary plane P1 and central axis A is inclined with respect to first center line B1.

Also, as shown in the schematic diagram of FIG. 8E when exhaust part 100g is mounted on a vehicle, the exhaust flow path downstream of catalyst case 4, more specifically, the opening on the side where exhaust gas flows out of downstream cone 5, may be positioned so as not to face the internal combustion engine.

(4d) In the above embodiment, the configuration of the exhaust part 100 having one catalyst case 4 is illustrated, but the configuration of the exhaust part 100 is not limited to this. For example, as in the exhaust part 100h shown in FIG. 9A, two catalyst cases 4b, 4c arranged parallel to each other may be provided. Also, as in the exhaust part 100i shown in FIG. 9B, two catalyst cases 4b, 4c arranged perpendicular to each other may be provided. Although not shown, the exhaust parts 100h and 100i in FIGS. 9A and 9B also have a bent portion 32 in a predetermined range between the upstream flange 1 and the first catalyst case 4b, which is considered to be easily damaged by thermal stress caused by thermal expansion along the flow direction of the exhaust gas.

(4e) In the above embodiment, a configuration in which one bending portion 32 is provided on the upstream cone 3 so as to extend along the circumferential direction of the upstream cone 3a is exemplified, but the configuration of the bending portion provided on the upstream cone is not limited to this.

For example, as shown in Figures 10 and 11, two bent portions 32a, 32b may be provided at an interval along the flow direction of the exhaust gas on the upstream cone 3a. Both of the two bent portions 32a, 32b have a length in the circumferential direction of the upstream cone 3a.
Also, for example, as shown in FIG. 12, two bent portions 32c, 32d may be provided at an upstream cone 3b at an interval along the circumferential direction of the upstream cone 3b.

(4f) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. In addition, part of the configuration of the above embodiments may be omitted. In addition, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. All aspects included in the technical idea identified from the wording of the claims are embodiments of the present disclosure.

1, 1a, 1b... upstream flange, 2, 2a to 2d... exhaust manifold, 3, 3a, 3b... upstream cone, 4, 4a to 4c... catalyst case, 5... downstream cone, 6... tubular member, 7... downstream flange, 11 to 14... through hole, 15... flange plane, 21 to 24... exhaust pipe, 25... junction, 31... wall, 32, 32a to 32c... bending portion, 100, 100a to 100i... exhaust part, bending point 321, A... central axis, B1... first center line, B2... second center line, C1... first range, C2... second range, F1, F2... reaction force, P1... first imaginary plane, P2... second imaginary plane.

Claims (7)

An exhaust part that forms an exhaust flow path that guides exhaust gas from an internal combustion engine,
The exhaust part includes:
an exhaust manifold including: a flange having at least one through hole formed therein, the through hole functioning as an inlet through which exhaust gas from the internal combustion engine flows; and at least one exhaust pipe through which the exhaust gas that has passed through the at least one through hole flows;
a catalyst case that is disposed downstream of the exhaust manifold and has a cylindrical portion that houses a catalyst that purifies exhaust gas;
an intermediate portion, which is a portion of the exhaust component that is located downstream of the at least one exhaust pipe and upstream of the tubular portion, and in which a cross-sectional area of the portion perpendicular to a flow direction of the exhaust gas increases toward the downstream side;
the intermediate portion has at least one bending portion having a plurality of bending points at which a curvature changes in a wall portion forming the intermediate portion ,
When the intermediate portion is viewed from the upstream side, the at least one bending portion is not provided at a position facing the at least one bending portion with respect to an upstream opening of the intermediate portion as a center,
The at least one bent portion is curved in an arc shape along a circumferential direction of the intermediate portion . An exhaust part that forms an exhaust flow path that guides exhaust gas from an internal combustion engine,
The exhaust part includes:
an exhaust manifold including: a flange having at least one through hole formed therein, the through hole functioning as an inlet through which exhaust gas from the internal combustion engine flows; and at least one exhaust pipe through which the exhaust gas that has passed through the at least one through hole flows;
a catalyst case that is disposed downstream of the exhaust manifold and has a cylindrical portion that houses a catalyst that purifies exhaust gas;
an intermediate portion, which is a portion of the exhaust component that is located downstream of the at least one exhaust pipe and upstream of the tubular portion, and in which a cross-sectional area of the portion perpendicular to a flow direction of the exhaust gas increases toward the downstream side;
the intermediate portion has at least one bending portion having a plurality of bending points at which a curvature changes in a wall portion forming the intermediate portion ,
When the intermediate portion is viewed from the upstream side, the at least one bending portion is not provided at a position facing the at least one bending portion with respect to an upstream opening of the intermediate portion as a center,
the at least one refraction portion is a plurality of refraction portions,
The plurality of bent portions are spaced apart from one another along the flow direction . 3. An exhaust component according to claim 1 or 2 ,
The bent portion is a recess in which a part of the wall portion is recessed inward. An exhaust component according to any one of claims 1 to 3 ,
The flange is a plate-shaped member,
the at least one through hole is a plurality of through holes,
The arrangement direction of the plurality of through holes is defined as a longitudinal direction of the flange,
an exhaust part in which, when the exhaust part is projected onto a first imaginary plane along a plane in which the plurality of through holes of the flange are formed, a central axis of the cylindrical part is positioned deviated from a first center line that is a line passing through the center of the longitudinal direction of the flange and is a line perpendicular to the longitudinal direction, and the bent part is located in a range on the first center line side of the intermediate part. An exhaust component according to any one of claims 1 to 3 ,
The flange is a plate-shaped member,
the at least one through hole is a plurality of through holes,
A direction perpendicular to the longitudinal direction of the flange, which is an arrangement direction of the plurality of through holes, and a direction along a plane in which the plurality of through holes of the flange are formed is defined as a short-side direction of the flange,
The bent portion is an exhaust part that is located in a range on the flange side of the intermediate portion when the central axis of the tubular portion is inclined with respect to a second center line that is a line passing through the center of the flange in the short side direction and is a line perpendicular to the short side direction when the exhaust part is projected onto a second imaginary plane that is a plane perpendicular to a first imaginary plane along the plane and along the short side direction. An exhaust component according to any one of claims 1 to 3 ,
The flange is a plate-shaped member,
the at least one through hole is a plurality of through holes,
The arrangement direction of the plurality of through holes is defined as a longitudinal direction of the flange,
A direction perpendicular to the longitudinal direction and along a plane in which the plurality of through holes of the flange are formed is defined as a short-side direction of the flange,
The bent portion is an exhaust part that is located in a range on the first center line side of the intermediate portion and in a range on the flange side of the intermediate portion in the following state: when the exhaust part is projected onto a first imaginary plane that is along the flat surface, the central axis of the cylindrical part is disposed deviated from a first center line that is a line passing through the center of the flange in the longitudinal direction and is a line perpendicular to the longitudinal direction; and when the exhaust part is projected onto a second imaginary plane that is a plane perpendicular to the first imaginary plane and along the short side direction, the central axis is disposed inclined with respect to a second center line that is a line passing through the center of the flange in the short side direction and is a line perpendicular to the short side direction. An exhaust component according to any one of claims 1 to 6 ,
The bent portion has a length in a direction along a circumferential direction of the intermediate portion.

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