JP2021116758A - Exhaust system - Google Patents

Abstract

To provide a technique for increasing a mounting space for a vehicular battery in a vehicle where an exhaust system is arranged around the vehicular battery.SOLUTION: The exhaust system to form an exhaust flow path for exhaust gas exhausted from an internal combustion engine includes a purifier, and a noise eliminator, the purifier having a first purifying member and a second purifying member arranged in the exhaust flow path so that the exhaust gas flows in series, and one storage chamber storing the first purifying member and the second purifying member, the noise eliminator being located downstream of the purifier and having an inner pipe through which the exhaust gas passes, and an outer pipe forming a double pipe together with the inner pipe, the purifier being arranged on the front side of the vehicular battery in the longitudinal direction of the vehicle, and the noise eliminator being arranged on at least one of the left side and the right side of the vehicle battery in the cross direction of the vehicle.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an exhaust system.

As an exhaust system for automobiles, as described in Patent Document 1, a purification device arranged on the upstream side of the exhaust flow path of the exhaust gas exhausted from the internal combustion engine and a purification device arranged on the downstream side of the exhaust flow path. It is known that a sub muffler is provided between the main muffler and the main muffler.

Japanese Unexamined Patent Publication No. 2019-132266

By the way, in a hybrid vehicle provided with an internal combustion engine and an electric motor as a power source, a vehicle battery for supplying electric power to the electric motor is generally provided under the floor of the vehicle, so that the exhaust system is a vehicle battery. It is placed around. For example, the purification device is arranged on the front side of the vehicle battery, the sub muffler is arranged on at least one of the left side and the right side of the vehicle battery, and the main muffler is arranged on the rear side of the vehicle battery with reference to the front, rear, left and right directions of the vehicle. There is something to be done.

In a hybrid vehicle, it is desired to further increase the mounted capacity of the vehicle battery in order to increase the operating time of the electric motor. However, as a result of detailed examination by the inventor, it has been found that the exhaust system arranged around the vehicle battery regulates the mounting space of the vehicle battery. When the exhaust system is arranged as described above, the purification device regulates the mounting space of the vehicle battery in the front-rear direction of the vehicle, and the silencer as a submuffler regulates the mounting space of the vehicle battery in the left-right direction of the vehicle.

One aspect of the present disclosure provides a technique for increasing the mounting space of a vehicle battery in a vehicle in which an exhaust system is arranged around the vehicle battery.

One aspect of the present disclosure is an exhaust system in which a vehicle battery is mounted on a vehicle provided under the floor to form an exhaust flow path for exhaust gas exhausted from an internal combustion engine, and includes a purification device and a silencer. .. The purification device is one that houses a first purification member and a second purification member arranged so that the exhaust gas flows in series in the exhaust flow path, and a first purification member and a second purification member. It has a containment chamber. The silencer is located on the downstream side of the exhaust flow path from the purification device, and has an inner pipe through which the exhaust gas passes, and an outer pipe forming a double pipe together with the inner pipe. The purification device is arranged on the front side of the vehicle battery in the front-rear direction of the vehicle. The silencers are arranged on at least one of the left and right sides of the vehicle battery in the left-right direction of the vehicle.

According to such a configuration, the length of the purifying device in the vehicle front-rear direction is shortened, and the length of the silencer as a sub muffler in the vehicle left-right direction is shortened. Space can be expanded. Therefore, in a vehicle in which the exhaust system is arranged around the vehicle battery, the mounting space of the vehicle battery can be increased.

In one aspect of the present disclosure, the purification device may have a first purification member and a second purification member arranged so that the exhaust flow path bends from the first purification member to the second purification member.
According to such a configuration, the length of the purifying device in the vehicle front-rear direction can be further shortened, so that the mounting space of the vehicle battery in the vehicle front-rear direction can be further increased.

In one aspect of the present disclosure, in the purification device, the first purification member and the second purification member are arranged so that the exhaust flow path bends in an L shape from the first purification member to the second purification member. You may.
According to such a configuration, the length of the purifying device in the vehicle front-rear direction can be further shortened, so that the mounting space of the vehicle battery in the vehicle front-rear direction can be further increased.

In one aspect of the present disclosure, in the double pipe of the silencer, one of the first end and the second end is on the upstream side of the exhaust flow path, and the other is on the downstream side of the exhaust flow path. Therefore, a part of the exhaust flow path may be formed via the inner pipe. A gap is provided between the inner pipe and the outer pipe, an opening is provided between the inner pipe and the outer pipe at the second end, and the gap is configured to pass through the exhaust flow path through the opening. You may. The inner tube may have a first range and a second range. In the first range, the outer surface of the inner pipe is at the same position as the reference with respect to the position of the inner surface of the outer pipe. In the second range, the outer surface of the inner pipe is arranged inside the reference. The outer surface of the inner tube may reach the second end in each of the first and second ranges. In the first range, the inner pipe and the outer pipe are arranged at positions where the outer surface of the inner pipe and the inner side surface of the outer pipe are in contact with each other, so that the space between the inner pipe and the outer pipe is closed. It may be configured to. In the second range, a part of the gap may be formed between the outer surface of the inner pipe and the inner side surface of the outer pipe, and an opening may be formed at a position where the second range reaches the second end.

According to such a configuration, the outer diameter of the double pipe of the silencer can be made smaller than that of the case where the gap is secured only by inflating the outer pipe to the outer peripheral side, for example. Therefore, the length of the silencer as a sub muffler in the vehicle left-right direction can be shortened, and the space for mounting the vehicle battery in the vehicle left-right direction can be increased.

In one aspect of the present disclosure, in the double pipe of the silencer, one of the first end and the second end is on the upstream side of the exhaust flow path, and the other is on the downstream side of the exhaust flow path. Therefore, a part of the exhaust flow path may be formed via the inner pipe. A gap is provided between the inner pipe and the outer pipe, an opening is provided between the inner pipe and the outer pipe at the second end, and the gap is configured to pass through the exhaust flow path through the opening. You may. The inner tube may have a first range and a second range. The first range is the circumferential range in which inclusions are present between the outer surface of the inner pipe and the inner surface of the outer pipe, based on the position of the inner surface of the inclusions. Then, with reference to the position of the inner surface of the outer pipe, the outer surface of the inner pipe is at the same position as the reference. In the second range, the outer surface of the inner pipe is arranged inside the reference. The outer surface of the inner tube may reach the second end in each of the first and second ranges. In the first range, inclusions may be sandwiched between the outer surface of the inner pipe and the inner surface of the outer pipe so that the space between the inner pipe and the outer pipe is closed. In the second range, a part of the gap may be formed between the outer surface of the inner pipe and the inner side surface of the outer pipe, and an opening may be formed at a position where the second range reaches the second end.

According to such a configuration, the outer diameter of the double pipe of the silencer can be made smaller than that of the case where the gap is secured only by inflating the outer pipe to the outer peripheral side, for example. Therefore, the length of the silencer as a sub muffler in the vehicle left-right direction can be shortened, and the space for mounting the vehicle battery in the vehicle left-right direction can be increased.

In one aspect of the present disclosure, the inner tube may have a large diameter portion having a first diameter and a small diameter portion having a second diameter smaller than the first diameter. A resonance chamber corresponding to a part of the void may be formed between the outer surface of the small diameter portion and the inner surface of the outer tube. The large diameter portion is arranged at the second end portion, and the large diameter portion has a first range and a second range, and in the second range, between the outer surface of the large diameter portion and the inner surface of the outer pipe, A resonance tube corresponding to a part of the void may be formed. There is an opening at one end of the resonance tube, the resonance tube leads to the exhaust flow path through the opening, and the resonance chamber communicates with the exhaust flow path through the resonance tube, so that the resonance tube and the resonance chamber become a Helmholtz resonator. It may be configured to function as.

According to such a configuration, the outer diameter of the double pipe of the silencer can be reduced while maintaining the muffling function. Therefore, the length of the silencer as a sub muffler in the vehicle left-right direction can be shortened, and the space for mounting the vehicle battery in the vehicle left-right direction can be increased.

In one aspect of the present disclosure, the outer diameter within the range from the first end to the second end of the outer pipe may be equal to or less than the outer diameter of the outer pipe at the second end.
According to such a configuration, the outer diameter of the double pipe of the silencer can be reduced. Therefore, the length of the silencer as a sub muffler in the vehicle left-right direction can be shortened, and the space for mounting the vehicle battery in the vehicle left-right direction can be increased.

It is a block diagram which shows the arrangement of an exhaust system and a vehicle battery. It is a perspective view which shows the structure of the purification apparatus. FIG. 3A is an explanatory view of the submuffler 5 of the first embodiment as viewed from the second end side. FIG. 3B is a cross-sectional view of the cut portion shown by the line IIIB-IIIB in FIG. 3A. FIG. 3C is an enlarged end view of the cut portion shown by the line IIIC-IIIC in FIG. 3B. FIG. 3D is an enlarged end view of the cut portion shown by the line IIID-IIID in FIG. 3B. It is a block diagram which shows the arrangement of the exhaust system and the vehicle battery of the comparative example. FIG. 5A is an end view of a cut portion showing a first modification of the portion shown in FIG. 3C. FIG. 5B is an end view of a cut portion showing a second modification of the portion shown in FIG. 3C. FIG. 5C is an end view of the cut portion showing a third modification of the portion shown in FIG. 3C. FIG. 5D is an end view of a cut portion showing a fourth modified example of the portion shown in FIG. 3C. FIG. 6A is an explanatory view of the modified submuffler 51 as viewed from the second end side. FIG. 6B is a cross-sectional view of the cut portion shown by the VIB-VIB line in FIG. 6A. FIG. 6C is an explanatory view of the modified submuffler 61 as viewed from the second end side. FIG. 6D is a cross-sectional view of the cut portion shown by the VID-VID line in FIG. 6C. FIG. 7A is an explanatory view of the modified submuffler 76 as viewed from the second end side. FIG. 7B is a cross-sectional view of the cut portion shown by the line VIIB-VIIB in FIG. 7A. FIG. 7C is an explanatory view of the modified submuffler 76 as viewed from the first end side. FIG. 7D is an explanatory view of the modified submuffler 81 as viewed from the second end side. FIG. 7E is a cross-sectional view of the cut portion shown by the line VIEE-VIIE in FIG. 7D. FIG. 7F is an explanatory view of the modified submuffler 81 as viewed from the first end side. FIG. 8A is an explanatory view of the modified submuffler 86 as viewed from the second end side. FIG. 8B is a cross-sectional view taken along the line VIIIB-VIIIB in FIG. 8A. FIG. 8C is an explanatory view of the modified sub muffler 86 as viewed from the first end side. FIG. 8D is an explanatory view of the modified submuffler 91 as viewed from the second end side. FIG. 8E is a cross-sectional view taken along the line VIIIE-VIIIE in FIG. 8D. FIG. 8F is an explanatory view of the modified submuffler 91 as viewed from the first end side. FIG. 9A is a schematic side view of the submuffler 203 of the second embodiment as viewed from the second end side. FIG. 9B is a schematic cross-sectional view taken along the line IXB-IXB of FIG. 9A. 10A, 10B and 10C are schematic views for explaining the shape of the communication hole. FIG. 11A is a schematic cross-sectional view taken along the line XIA-XIA of FIG. 9B. 11B is a schematic cross-sectional view taken along the line XIB-XIB of FIG. 9B. FIG. 11C is a schematic cross-sectional view taken along the line XIC-XIC of FIG. 9B. 12A and 12B are schematic views for explaining the relationship between the communication hole and the standing wave. FIG. 13 is a schematic cross-sectional view corresponding to FIG. 9B of a submuffler of an embodiment different from that of FIG. 9A. 14A, 14B and 14C are schematic cross-sectional views corresponding to FIG. 11A of a fixed portion of an embodiment different from FIG. 9A. FIG. 15A is a graph showing the relationship between the frequency and the muffling volume in Comparative Example 1, FIG. 15B is a graph showing the relationship between the frequency and the muffling volume in the first embodiment, and FIG. 15C is a graph showing the relationship between the frequency and the muffling volume in the second embodiment. It is a graph which shows the relationship between a frequency and a muffling volume. It is a block diagram which shows the arrangement of the exhaust system and the battery for a vehicle which changed the arrangement of a purification device. It is a block diagram which shows the arrangement of the exhaust system and the vehicle battery of the structure which the submuffler is bent.

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
The exhaust system 1 shown in FIG. 1 is mounted on a hybrid vehicle. The hybrid vehicle includes an engine 100, which is an internal combustion engine, and an electric motor as power sources. In the hybrid vehicle of the present embodiment, a vehicle battery 200 for supplying electric power to an electric motor is provided under the floor of the vehicle. The vehicle battery 200 is housed in a substantially rectangular parallelepiped case. The case in which the vehicle battery 200 is housed is installed so that the upper surface and the bottom surface face the vehicle in the vertical direction and the side surfaces face the vehicle in the front-rear direction and the left-right direction, respectively, in a state of being arranged in the vehicle. The vehicle battery 200 is arranged so as to occupy a large mounting space near the center of the vehicle when viewed from above the vehicle.

The exhaust system 1 forms an exhaust flow path for exhaust gas exhausted from the engine 100. The exhaust system 1 includes a purification device 3, a sub muffler 5, a main muffler 7, and pipe materials 9A, 9B, 9C (hereinafter, also referred to as pipe materials 9 when individual pipe materials are not distinguished), and these members. Is connected in series. The purification device 3 and the sub muffler 5 are connected by a pipe material 9A. The sub muffler 5 and the main muffler 7 are connected by a pipe material 9B. The exhaust gas that has passed through the main muffler 7 is discharged from the pipe material 9C. Although not shown, the exhaust gas exhausted from the engine 100 is configured to flow into the purification device 3 via the exhaust manifold. As described above, since the vehicle battery 200 is installed occupying a large mounting space near the central portion under the vehicle floor, the exhaust system 1 is arranged so as to bypass the vehicle battery 200 and extend in the front-rear direction of the vehicle. Has been done.

The purification device 3 is a device that reforms or collects environmental pollutants in the exhaust gas exhausted from the engine 100 by a purification member. In the purification device 3, the first purification member 31 and the second purification member 32 arranged so that the exhaust gas flows in series in the exhaust flow path, and the first purification member 31 and the second purification member 32 are arranged. It has one storage chamber 30 to be housed, and a casing 33 that forms the storage room 30 inside. Here, arranging the exhaust gas flows in series means that the first purification member and the second purification member are sequentially arranged in a line in the exhaust flow path, and are arranged in a line in order. The term "arranged" is not limited to the case where both members are arranged in a straight line, but also includes the case where both members are arranged in a non-linear manner as in the present embodiment. In the purification device 3, the first purification member 31 and the second purification member 32 are arranged so that the exhaust flow path bends in an L shape from the first purification member 31 to the second purification member 32. The accommodation chamber 30 is also bent in an L shape like the exhaust flow path, and the outer shape of the casing 33 is also bent in an L shape. The detailed structure of the purification device 3 will be described later.

Both the sub muffler 5 and the main muffler 7 are devices for reducing exhaust noise.
The sub muffler 5 is a silencer located on the downstream side of the exhaust flow path with respect to the purification device 3 and having a double pipe structure for passing exhaust gas.

The main muffler 7 further silences the exhaust gas that has passed through the sub muffler 5.
The purification device 3 is arranged on the front side of the vehicle battery 200 in the front-rear direction of the vehicle. The sub muffler 5 is arranged on at least one of the left side and the right side of the vehicle battery 200 in the left-right direction of the vehicle. In the present embodiment, the sub muffler 5 is arranged only on the right side of the vehicle battery 200 in the left-right direction of the vehicle. The main muffler 7 is arranged behind the vehicle battery 200 in the front-rear direction of the vehicle. Further, the exhaust system 1 is arranged at a height substantially equal to that of the vehicle battery 200 in the vertical direction of the vehicle. Specifically, the purification device 3 is arranged so that at least a part of the casing 33 faces the front surface of the case in which the vehicle battery 200 is housed. Further, the sub muffler 5 is arranged so that at least a part of the outer pipe 13 faces the right side surface of the case in which the vehicle battery 200 is housed.

<Purification device>
As described above, the purification device 3 shown in FIG. 2 includes a first purification member 31, a second purification member 32, and one storage chamber 30, and includes a first purification member 31 and a second purification member 31. The member 32 has a tandem structure in which the member 32 is housed in one storage chamber 30. Here, the tandem structure is a structure in which two purification members arranged in series are housed in one storage chamber, and the diameter of the portion sandwiched between the two purification members in the storage chamber is the diameter of the mainstream pipe. In other words, it means a structure larger than the diameter of the mainstream pipe, which is not narrowed down to the same size as. The mainstream pipe is a pipe that is connected to each of the upstream end and the downstream end of the purification device to form an exhaust flow path. In the present embodiment, the mainstream pipe connected to the downstream end of the purification device 3 is the pipe material 9A. The casing that forms the accommodation chamber inside may be formed of the same member in all parts, or may be formed by combining a plurality of members. In the present embodiment, the casing 33 is formed by combining a plurality of members of the introduction portion 331, the first connection portion 332, the bending portion 333, and the second connection portion 334, which will be described later.

The first purification member 31 and the second purification member 32 are members having a function of modifying or collecting environmental pollutants in the exhaust gas exhausted from the engine 100 by the purification member. The environmental pollutant means, for example, hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (PM) and the like. The first purification member 31 and the second purification member 32 may be of any kind, such as a catalyst or a filter, as long as they have the above-mentioned functions. Specific examples include, for example, a three-way catalyst that purifies HC, CO, and NOx in the exhaust gas, and a GPF that is a filter that collects PM in the exhaust gas. Further, the first purification member 31 and the second purification member 32 may be members of the same type or different types.

The detailed structure of the purification device 3 will be described below. In FIG. 2, the flow direction of the exhaust gas is indicated by a white arrow.
The casing 33 includes an introduction portion 331, a first connection portion 332, a bending portion 333, and a second connection portion 334. The introduction portion 331, the first connection portion 332, the bending portion 333, and the second connection portion 334 are each formed in a tubular shape, and the flow paths 20 communicate with each other in order so that the inside of the pipe becomes the exhaust flow path 20. It is configured as follows.

The introduction unit 331 is located on the most upstream side of the exhaust flow in the purification device 3, and is a portion where the exhaust gas exhausted from the engine 100 is introduced.
The first connection portion 332 is a portion having a linear flow path 20 communicating with the flow path 20 in the introduction section 331 on the downstream side of the introduction section 331. The bent portion 333 is a portion having an exhaust flow path 20 that bends on the downstream side of the first connecting portion 332. The second connecting portion 334 is a portion having a linear flow path 20 communicating with the flow path 20 in the bending portion 333 on the downstream side of the bending portion 333. In the present embodiment, the direction of the flow path 20 in the first connection portion 332 and the direction of the flow path 20 in the second connection portion 334 are orthogonal to each other in the bending portion 333. That is, as described above, the casing 33 has an L-shaped outer shape.

The first purification member 31 and the second purification member 32 are formed in a cylindrical shape, respectively, and are arranged and held in the first connection portion 332 and the second connection portion 334, respectively. That is, the first purification member 31 and the second purification member 32 are arranged in the accommodation chamber 30 so as to sandwich the bent portion 333.

As shown in FIG. 1, in the present embodiment, in the purification device 3, the second connection portion 334 in which the second purification member 32 is housed is left and right of the vehicle along the front surface of the case in which the vehicle battery 200 is housed. It is arranged so as to extend in the direction.

<Sub muffler>
As shown in FIGS. 3A and 3B, the submuffler 5 includes an inner tube 11 and an outer tube 13. Both the inner pipe 11 and the outer pipe 13 are formed in a tubular shape. The inner pipe 11 is arranged on the inner peripheral side of the outer pipe 13, whereby the inner pipe 11 and the outer pipe 13 form a double pipe 15 in the range A1 shown in FIG. 3B. In the following description, one end (the left end in FIG. 3B) of the double pipe 15 is referred to as a first end portion 15A, and the other end (the right end in FIG. 3B) is referred to as a second end portion 15B.

The above-mentioned pipe members 9A and 9B are connected to the first end portion 15A and the second end portion 15B, respectively. As a result, at the first end portion 15A, the inner peripheral side of the inner pipe 11 is continuous with the first flow path on the upstream side in the flow direction of the exhaust gas. Further, at the second end portion 15B, the inner peripheral side of the outer pipe 13 is continuous with the second flow path on the downstream side in the flow direction of the exhaust gas. That is, an exhaust flow path connecting the first flow path and the second flow path is configured via the inner pipe 11.

However, either the first end portion 15A or the second end portion 15B may be on the upstream side of the exhaust flow path. Specifically, even if the second end portion 15B is made continuous with the first flow path on the upstream side in the exhaust flow direction, and the first end portion 15A is made continuous with the second flow path on the downstream side in the exhaust flow direction. good. Further, although separate pipe materials 9A and 9B may be joined to the inner pipe 11 and the outer pipe 13, the inner pipe 11 and the outer pipe 13 themselves are integrally molded up to the portion corresponding to the pipe materials 9A and 9B. May be good.

A gap 17 is provided between the inner pipe 11 and the outer pipe 13. More specifically, as shown in FIG. 3B, the inner pipe 11 has a large diameter portion 21 having a maximum outer diameter of the first diameter R1 and a second diameter portion 21 having a maximum outer diameter smaller than the first diameter R1. It has a shape having a small diameter portion 23 having a diameter R2 of. The large diameter portion 21 is arranged on the second end portion 15B side, and the small diameter portion 23 is arranged on the first end portion 15A side. On the other hand, the outer diameter of the outer pipe 13 is substantially the same as the maximum outer diameter of the inner pipe 11 in most of the range continuous from the second end 15B. However, the outer diameter of the outer pipe 13 is narrowed down as shown in FIG. 3B only in a part near the first end portion 15A, and the outer diameter becomes smaller toward the first end portion 15A side.

Since the inner tube 11 and the outer tube 13 are shaped as described above, a resonance chamber corresponding to a part of the gap 17 is provided between the outer peripheral surface of the small diameter portion 23 and the inner peripheral surface of the outer tube 13. 17A is configured. Further, in the large diameter portion 21, as shown in FIG. 3C, a part of the outer peripheral surface of the inner pipe 11 is recessed toward the inner peripheral side. As a result, a resonance tube 17B corresponding to a part of the gap 17 is formed between a part of the outer peripheral surface of the large diameter portion 21 and the inner peripheral surface of the outer tube 13.

That is, in the place where the resonance chamber 17A and the resonance tube 17B are formed, the inner tube 11 has a part of the outer peripheral surface of the inner tube 11 inside the reference with respect to the position of the inner peripheral surface of the outer tube 13. The shape is arranged on the peripheral side. As a result, the resonance chamber 17A and the resonance tube 17B as described above are formed between a part of the outer peripheral surface of the inner tube 11 and the inner peripheral surface of the outer tube 13.

In the case of the present embodiment, the center of curvature of the recess on the outer peripheral surface of the inner tube 11 provided at the portion constituting the resonance tube 17B is on the outer peripheral side of the inner tube 11. Further, the radius of curvature R3 of the dent has substantially the same dimensions as the maximum radius R4 of the inner pipe 11 (that is, the radius of the portion without the dent). As a result, when a dent is provided in a tube having a circular cross section in post-processing, the circumferential length of the tube can be made substantially the same before and after processing, so that the dent can be provided while maintaining the wall thickness of the tube. .. However, it is arbitrary whether or not such a dent is provided by post-processing, and a tube formed in advance into a dented shape may be used.

At the first end portion 15A, the inner pipe 11 and the outer pipe 13 are in contact with each other, whereby the space between the inner pipe 11 and the outer pipe 13 is closed. In the case of the present embodiment, the inner pipe 11 and the outer pipe 13 are welded over the entire circumference at the first end portion 15A. On the other hand, in the second end portion 15B, there is an opening 19 between the inner pipe 11 and the outer pipe 13. The opening 19 is located at one end of the resonance tube 17B described above, and the resonance tube 17B leads to the exhaust flow path through the opening 19. Further, the other end of the resonance tube 17B communicates with the resonance chamber 17A, and the resonance chamber 17A communicates with the exhaust flow path via the resonance tube 17B.

By providing such a resonance tube 17B and a resonance chamber 17A, the resonance tube 17B and the resonance chamber 17A are configured to function as a Helmholtz resonator. More specifically, as shown in FIG. 3D, the resonance chamber 17A has a cross-sectional area perpendicular to the axial direction of the outer tube 13 larger than that of the resonance tube 17B and is larger than the resonance tube 17B in the axial direction of the outer tube 13. The length parallel to the resonance tube 17B is longer than that of the resonance tube 17B, and the volume is sufficiently larger than that of the resonance tube 17B. On the other hand, as shown in FIG. 3C, the resonance tube 17B has a cross-sectional area perpendicular to the axial direction of the outer tube 13 smaller than that of the resonance chamber 17A.

As shown in FIG. 1, in the present embodiment, the submuffler 5 is arranged so as to extend in the front-rear direction of the vehicle along the right side surface of the case in which the vehicle battery 200 is housed.
[1-2. effect]
According to the first embodiment described in detail above, the following effects can be obtained.

(1-2a) The exhaust system 1 includes a tandem-structured purification device 3 in which the first purification member 31 and the second purification member 32 are housed in one storage chamber 30, an inner pipe 11 for passing exhaust gas, and an outside. A sub-muffler 5 having a double pipe 15 composed of a pipe 13 is provided, the purification device 3 is arranged in front of the vehicle battery 200 in the front-rear direction of the vehicle, and the sub-muffler 5 is the vehicle battery 200 in the left-right direction of the vehicle. It is placed on at least one of the left side and the right side of the. According to such a configuration, the length of the purification device 3 in the vehicle front-rear direction is shortened as compared with the purification device having no tandem structure, and the vehicle of the sub muffler 5 is compared with the sub muffler having no double pipe. Since the length in the left-right direction is shortened, the mounting space of the vehicle battery 200 can be expanded by the shortened amount. This will be described with reference to FIG.

The exhaust system 1D of the comparative example shown in FIG. 4 is different from the exhaust system 1 of the above embodiment in that it includes a purification device 3D that does not have a tandem structure and a submuffler 5D that does not have a double pipe. Since the components other than the purification device 3D, the submuffler 5D, and the vehicle battery 200D in the exhaust system 1D have the same configurations as those in the above embodiment, the same symbols as those in the above embodiment are used.

The purification device 3D has two storage chambers 30D and 30E, a casing 33D forming the storage chamber 30D inside, and a casing 33E forming the storage chamber 30E inside, and the storage chamber 30D has a first purification device. The member 31D is housed, and the second purification member 32D is housed in the casing 30E. The casing 33D and the casing 33E are connected by a mainstream pipe 9D. In this case, at the ends of the casing 33D and the casing 33E on the mainstream pipe 9D side, it is necessary to provide a tapered portion for reducing the diameters of the accommodation chamber 30D and the accommodation chamber 30E to the same size as the diameter of the mainstream pipe 9D. Therefore, in the purification device 3D, the distance between the first purification member 31D and the second purification member 32D is such that the distance between the first purification member 31 and the second purification member 32 in the tandem structure purification device 3 It will be longer than the distance between them. Therefore, the length of the purification device 3D in the vehicle front-rear direction is longer than the length of the purification device 3 in the vehicle front-rear direction. That is, in the exhaust system 1, since the length of the purification device 3 in the vehicle front-rear direction is shortened as compared with the purification device 3D, the mounting space of the vehicle battery 200 can be expanded in the vehicle front direction by the shortened amount.

Further, the sub muffler 5D is a silencer having a structure that does not have a double pipe, and has a shape in which the outer shape is greatly bulged outward. Therefore, the length of the sub muffler 5D in the vehicle left-right direction is longer than the length of the sub-muffler 5 in the vehicle left-right direction. That is, in the exhaust system 1, since the length of the sub muffler 5 in the vehicle left-right direction is shortened as compared with the sub-muffler 5D, the mounting space of the vehicle battery 200 can be expanded in the vehicle left-right direction by the shortened amount.

Therefore, in a vehicle in which the exhaust system 1 is arranged around the vehicle battery 200, the mounting space of the vehicle battery 200 can be increased.
(1-2b) In the purification device 3, the first purification member 31 and the second purification member 32 are bent in an L shape from the first purification member 31 to the second purification member 32. Is placed. According to such a configuration, the length of the purification device 3 in the vehicle front-rear direction can be further shortened as compared with the case where the first purification member 31 and the second purification member 32 are arranged in a straight line. The mounting space of the battery 200 in the front-rear direction of the vehicle can be further increased.

(1-2c) According to the submuffler 5 having the above configuration, a gap 17 is provided between the inner pipe 11 and the outer pipe 13 constituting the double pipe 15, and the inner pipe 11 and the outer pipe 11 are provided at the second end portion 15B. An opening 19 is provided between the pipe 13 and the void 17 so as to communicate with the exhaust flow path through the opening 19. As a result, in the case of the present embodiment, the resonance tube 17B and the resonance chamber 17A function as a Helmholtz resonator, and a sound deadening effect is exhibited.

If the sub muffler 5 has such a structure, the inner pipe 11 does not need to be provided with a small hole. Therefore, the inner pipe 11 is bent without considering the deformation of the small hole. Is possible. Therefore, better bending workability can be ensured than when the inner pipe 11 having a small hole is used. Therefore, the sub muffler 5 can be arranged even at the bent portion of the exhaust pipe, and a place having a higher sound deadening effect can be selected. Therefore, it is difficult to arrange the sub muffler 5 at the bent portion of the exhaust pipe. Compared with, the muffling effect can be exerted more appropriately.

Further, in providing the gap 17 as described above, the shape of the inner pipe 11 is based on the position of the inner peripheral surface of the outer pipe 13, and a part of the outer peripheral surface of the inner pipe 11 is on the inner peripheral side of the reference. The gap 17 is formed by the shape arranged in. Therefore, for example, the outer diameter of the double pipe 15 can be made smaller than in the case where the gap 17 is secured only by inflating the outer pipe 13 toward the outer peripheral side. Therefore, the length of the sub muffler 5 in the vehicle left-right direction can be shortened, and the mounting space of the vehicle battery 200 in the vehicle left-right direction can be increased. Further, the sub muffler 5 can be arranged even in a narrower arrangement place. Therefore, the degree of freedom in deciding where to place the sub muffler 5 is increased, and a place with a higher muffling effect can be selected. Can be made to.

Further, in the case of the sub muffler 5, an opening 19 is provided in the second end portion 15B of the double tube 15 to form a resonance tube 17B extending in the same direction as the axial direction of the double tube 15. Therefore, the axial length of the resonance tube 17B can be easily increased as compared with the case where the through hole penetrating the inner tube 11 in the radial direction is used as the resonance tube. The resonance frequency f in the Helmholtz resonator can be calculated by the following formula (1) based on the sound velocity C, the resonance tube cross-sectional area S, the resonance tube length L, and the resonance chamber volume V.

Therefore, if the axial length L of the resonance tube 17B can be increased, the resonance frequency f can be set low. On the other hand, when the through hole penetrating the inner tube 11 in the radial direction (that is, the wall thickness direction of the inner tube 11) is used as a resonance tube, the resonance tube length L is at most the wall thickness of the inner tube 11. Only up to the same size can be secured. Here, as a method of lowering the resonance frequency f, there is also a method of reducing the resonance tube cross-sectional area S. However, if the resonance tube cross-sectional area S is reduced, there is a problem that the sound deadening effect itself is weakened even if the resonance frequency f can be lowered. It is possible to extend the resonance tube length L by connecting a pipe to the through hole of the inner tube 11, but the structure becomes complicated by the amount of the additional pipe, which leads to a decrease in productivity and an increase in the size of the entire structure. In this regard, if a structure like the submuffler 5 is adopted, the axial length of the resonance tube 17B can be easily set to a desired dimension, so that the resonance frequency can be easily lowered while ensuring a sufficient noise suppression effect. It can be set and the exhaust noise of the target frequency can be reduced.

Further, in the case of the sub muffler 5, the outer pipe 13 has a shape in which the outer diameter within the range from the first end portion 15A to the second end portion 15B is equal to or less than the outer diameter of the outer pipe 13 at the second end portion 15B. Has been done. Therefore, the outer diameter of the double pipe 15 can be made smaller than that of the submuffler having a portion where the outer diameter of the double pipe 15 is larger than that of the second end portion 15B. Therefore, the length of the sub muffler 5 in the vehicle left-right direction can be shortened, and the mounting space of the vehicle battery 200 in the vehicle left-right direction can be increased. Further, the sub muffler 5 can be arranged in a narrower arrangement place.

(1-2d) In the case of the sub-muffler 5 described above, since the sub-muffler 5 has a double pipe 15, the presence of the gap 17 increases the heat insulating property as compared with the sub-muffler having no double pipe. Therefore, since the heat of the exhaust gas passing through the inside of the sub muffler 5 is less likely to be transferred to the outside, the sub muffler 5 can be arranged closer to the vehicle battery 200.

(1-2e) In the exhaust system 1, the length of the purification device 3 in the vehicle front-rear direction is shortened, so that the space for mounting the submuffler 5 arranged on the right side of the vehicle battery 200 is increased by the shortened length. It can be expanded in the front direction of the vehicle. Therefore, it is possible to set the length of the sub muffler 5 in the vehicle front-rear direction to be longer, so that the frequency range of the muffling target can be expanded to a lower range.

In the first embodiment, the sub mufflers 5, 51, 61, 76, 81, 86, 91 correspond to the silencer.
[1-3. Deformation example of sub muffler]
(1-3a) In the above embodiment, in FIG. 3C, the resonance tube 17B is formed by providing the upper and lower two points of the inner tube 11 with dents having a convex shape toward the inner peripheral side. The number of tubes 17B and the shape of the recess provided on the outer periphery of the inner tube 11 for forming the resonance tube 17B are not limited to the above examples.

For example, as shown in FIG. 5A, a resonance tube 17B having the same shape as the resonance tube 17B shown in FIG. 3C may be provided only at one location on the lower side of the inner tube 11. A similar resonance tube 17B may be provided at a location other than the lower side of the inner tube 11, but if the resonance tube 17B is provided under the inner tube 11, dew condensation will occur on the inner peripheral surface of the outer tube 13. When water collects inside the outer tube 13 (for example, inside the resonance chamber 17A), there is a possibility that the water can be discharged to the outside through the resonance tube 17B. Therefore, considering such an advantage, it is preferable to configure the resonance tube 17B at least below the inner tube 11. However, since another drainage measure can be adopted for the water inside the outer pipe 13, it is not essential to provide the resonance pipe 17B under the inner pipe 11.

Further, as shown in FIG. 5B, the resonance tube 17B may be configured by providing flat-shaped portions at two positions above and below the inner tube 11. Even with such a flat-shaped portion, when the position where the entire outer peripheral surface of the inner pipe 11 is in contact with the inner peripheral surface of the outer pipe 13 is used as a reference, the flat-shaped portion is on the inner peripheral side of the reference. Since the shape is arranged, the resonance tube 17B can be configured.

Further, as shown in FIG. 5C, the resonance tube 17B may be formed by providing a portion having a convex shape toward the outer peripheral side at one location on the lower side of the inner tube 11. Even if the portion has a convex shape toward the outer peripheral side, the shape is convex toward the outer peripheral side based on the position where the entire outer peripheral surface of the inner pipe 11 is in contact with the inner peripheral surface of the outer pipe 13. Since the portion has a shape arranged on the inner peripheral side of the reference, the resonance tube 17B can be formed. As shown in FIG. 5D, the resonance tube 17B may be formed by providing two upper and lower portions of the inner tube 11 having a convex shape toward the outer peripheral side. As shown in FIGS. 5C and 5D, the center of curvature of such a convex portion is on the outer peripheral side of the inner tube 11.

(1-3b) The sub muffler 51 shown in FIGS. 6A and 6B is not located at the position where the inner pipe 11 and the outer pipe 13 are in contact with each other at the first end portion 15A. Since the 53 is sandwiched between the inner pipe 11 and the outer pipe 13, the space between the inner pipe 11 and the outer pipe 13 is blocked. In this way, the inner pipe 11 and the outer pipe 13 may be closed by a method other than welding.

Although not shown, inclusions such as a wire mesh 53 may be sandwiched between the inner pipe 11 and the outer pipe 13 also at the second end portion 15B. However, since the opening 19 as described above is provided at the second end portion 15B and a gap serving as the resonance tube 17B is secured, no inclusions are arranged at the positions corresponding to these openings 19 and the resonance tube 17B. ..

(1-3c) In the submuffler 61 shown in FIGS. 6C and 6D, the shape of the inner tube 11 is different from that of the above embodiment, and the portion having a cross-sectional shape corresponding to the large diameter portion 21 in the above embodiment is formed. A linear void 63 without a resonance chamber 17A is formed continuously over the entire length of the inner tube 11 in the axial direction. At the first end portion 15A, similarly to the submuffler 51 described above, the wire mesh 53 is sandwiched between the inner pipe 11 and the outer pipe 13, so that the space between the inner pipe 11 and the outer pipe 13 is closed. .. In the submuffler 61 configured in this way, the above-mentioned gap 63 functions as a side branch. That is, as shown in the above embodiment, the silencer of the present disclosure can be configured as a Helmholtz resonator type silencer or as a side branch type silencer.

(1-3d) In the above embodiment, the inner pipe 11 and the outer pipe 13 are closed at the first end portion 15A, and the opening 19 is opened between the inner pipe 11 and the outer pipe 13 at the second end portion 15B. However, in the case of the sub muffler 76 shown in FIGS. 7A, 7B and 7C, openings are provided in both the first end portion 15A and the second end portion 15B.

In the case of the sub muffler 76 shown in FIGS. 7A, 7B and 7C, a wire mesh 77 is sandwiched between the inner pipe 11 and the outer pipe 13 at the first end portion 15A. However, as shown in FIG. 7C, the wire mesh 77 has a shape in which a part of the wire mesh 77 is interrupted in the circumferential direction, and the opening 78 is formed by the interrupted portion.

Such an opening 78 can be adjusted in size and shape within a range in which the function of the resonance chamber 17A formed between the inner tube 11 and the outer tube 13 is not impaired, and such adjustment is performed. This makes it possible to adjust the frequency calculated as a characteristic of the Helmholtz resonator. As described in the above embodiment, the resonance frequency in the Helmholtz resonator can be changed by adjusting the resonance tube cross-sectional area, the resonance tube length, the resonance chamber volume, etc., but further adjust the size and shape of the opening 78. It can also be changed by doing. Therefore, as much as the adjustment by the opening 78 is possible, the means for adjusting the resonance frequency in the Helmholtz resonator is increased, and the degree of freedom in performing such adjustment is increased.

If openings are provided in both the first end portion 15A and the second end portion 15B, exhaust gas may also flow between the inner pipe 11 and the outer pipe 13. In that case, the inner pipe 11 Two exhaust flow paths will be configured on the outer peripheral side and the inner peripheral side. In this case, even if one of the exhaust flow paths is clogged, if the other exhaust flow path is not clogged, it is possible to prevent the exhaust flow path from being completely blocked.

Therefore, for example, in a cold region or the like where water accumulates in the exhaust pipe and the phenomenon of freezing the water is repeated many times, even if one of the exhaust channels is blocked by ice. There is room for exhaust gas to be discharged through the other exhaust flow path. Therefore, if there is a place where water tends to collect due to the shape of the curved exhaust pipe, by arranging the sub muffler 76 in such a place, in addition to the sound deadening effect, in the exhaust pipe You can also take measures against freezing.

(1-3e) In the sub muffler 81 shown in FIGS. 7D, 7E and 7F, a recess similar to that on the second end 15B side is formed on the outer periphery of the inner pipe 11 even at the first end 15A, and the opening 85 is formed. It is formed. The size and shape of such an opening 85 can also be adjusted within a range in which the function of the resonance chamber 17A formed between the inner tube 11 and the outer tube 13 is not impaired, and such adjustment is performed. This makes it possible to adjust the frequency calculated as a characteristic of the Helmholtz resonator. It should be noted that the point that two exhaust flow paths are secured is the same as the above-mentioned submuffler 76.

(1-3f) The submuffler 86 shown in FIGS. 8A, 8B and 8C differs from the submuffler 81 described above in the number of openings 19 provided on the second end portion 15B side, but other points. Is configured in the same manner as the submuffler 81 described above.

That is, also in the sub muffler 86 shown in FIGS. 8A, 8B and 8C, an opening 88 is formed by forming a recess on the outer periphery of the inner pipe 11 at the first end portion 15A. The size and shape of such an opening 88 can also be adjusted within a range in which the function of the resonance chamber 17A formed between the inner tube 11 and the outer tube 13 is not impaired, and such adjustment is performed. This makes it possible to adjust the frequency calculated as a characteristic of the Helmholtz resonator. It should be noted that the point that two exhaust flow paths are secured is the same as the above-mentioned submuffler 76.

(1-3g) The sub-muffler 91 illustrated in FIGS. 8D, 8E and 8F is different in shape on the first end 15A side in comparison with the above-mentioned sub-muffler 81, but the other points are the above-mentioned sub-muffler 81. It is configured in the same way as. In the sub muffler 91 shown in FIGS. 8D, 8E and 8F, a recess is formed on the outer periphery of the inner pipe 11 also at the first end portion 15A, and an opening 95 is formed. The size and shape of such an opening 95 can also be adjusted within a range in which the function of the resonance chamber 17A formed between the inner tube 11 and the outer tube 13 is not impaired, and such adjustment is performed. This makes it possible to adjust the frequency calculated as a characteristic of the Helmholtz resonator. It should be noted that the point that two exhaust flow paths are secured is the same as the above-mentioned submuffler 76.

[1-4. supplement]
As is clear from the exemplary embodiments described above, the silencer of the present disclosure may further include the following configurations.

First, in the silencer of the present disclosure, the inner pipe has a large diameter portion having a maximum outer diameter of the first diameter and a thin portion having a maximum outer diameter of a second diameter smaller than the first diameter. The shape has a diameter portion, and a resonance chamber corresponding to a part of the gap is formed between the outer peripheral surface of the small diameter portion and the inner peripheral surface of the outer pipe, and the large diameter portion is the second end portion. A resonance tube corresponding to a part of the gap is formed between a part of the outer peripheral surface of the large diameter portion and the inner peripheral surface of the outer tube, and there is an opening at one end of the resonance tube. The resonance tube and the resonance chamber may be configured to function as a Helmholtz resonator by communicating the resonance tube to the exhaust flow path via the resonance tube and the resonance chamber to the exhaust flow path through the resonance tube. ..

According to the silencer configured in this way, an opening can be provided at the end of the double tube to form a resonance tube extending in the same direction as the axial direction of the double tube. Therefore, the axial length of the resonance tube can be easily increased as compared with the case where the through hole penetrating the inner tube in the radial direction is used as the resonance tube. Therefore, the resonance frequency can be easily set lower while ensuring a sufficient noise suppression effect.

Further, in the silencer of the present disclosure, the outer pipe has a shape in which the outer diameter within the range from the first end portion to the second end portion is equal to or less than the outer diameter of the outer pipe at the second end portion. good.
According to the silencer configured in this way, there is no place where the outer diameter of the double pipe is larger than the second end, so that the place where the outer diameter of the double pipe is larger than the second end is located. Compared with the silencer having the silencer, the length of the silencer in the vehicle left-right direction can be shortened, and the mounting space of the vehicle battery in the vehicle left-right direction can be increased. In addition, the silencer can be placed in a narrower place.

Further, the silencer of the present disclosure corresponds to the abdomen of the sound pressure of a standing wave generated in the exhaust flow path when air column resonance occurs in the exhaust flow path composed of the exhaust flow path constituent members including the silencer. The opening may be arranged at the position where the opening is to be used.

According to the muffler configured in this way, it is possible to suppress the generation of resonance sound due to air column resonance, and it is possible to reduce the exhaust sound as compared with the case where the muffler is arranged at another position.
[2. Second Embodiment]
[2-1. Constitution]
In the exhaust system 201 of the second embodiment, only the configuration of the submuffler 203 is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment. I will explain mainly. Since the components other than the sub muffler 203 in the exhaust system 201 have the same configuration as that of the first embodiment, the same symbols as those of the first embodiment are used.

As shown in FIGS. 9A and 9B, the submuffler 203 includes a tubular inner tube 207, a tubular outer tube 208, and inclusions 209. The sub muffler 203 has a double tube structure.
(Inner tube)
The inner pipe 207 is configured so that the exhaust gas passes through the inside. Specifically, the exhaust gas that has passed through the purification device 3 is introduced into the inner pipe 207 from the first end portion 271 or the second end portion 272, and is discharged from the opposite end portion.

The inner pipe 207 has a plurality of communication holes 273A and 273B. Each of the plurality of communication holes 273A and 273B communicates the inside of the inner pipe 207 with a gap 210 provided between the outer pipe 208 and the inner pipe 207, which will be described later. The plurality of communication holes 273A and 273B are provided at positions separated from each other in the axial direction (that is, the longitudinal direction) of the inner pipe 207. Further, the plurality of communication holes 273A and 273B are arranged between the first end portion 281 and the second end portion 282 of the outer pipe 208 in the axial direction of the inner pipe 207.

The shapes of the communication holes 273A and 273B are not limited to a perfect circle as long as the area in which the side branch type silencer functions can be secured. The communication holes 273A and 273B may have an elliptical shape (see FIG. 10A), a polygonal shape, a polygonal shape with rounded corners (see FIG. 10B), a star shape, or the like. Further, each of the communication holes 273A and 273B may be divided into a plurality of small holes (that is, an aggregate of small holes, see FIG. 10C).

When air column resonance occurs in the second exhaust flow path (that is, the exhaust flow path in the entire exhaust system 201) composed of the exhaust flow path constituent members including the submuffler 203, the abdomen of the steady wave generated in the second exhaust flow path. The communication holes 273A and 273B are arranged at the positions corresponding to the above.

The inner diameter R6 of the second end 272 of the inner tube 207 is larger than the inner diameter R5 of the first end 271. Further, the second end portion 272 has one fixing portion 272A fixed to the inner peripheral surface of the outer pipe 208. As shown in FIG. 11A, the fixing portion 272A has two recesses 272B and 272C in which a part of the pipe wall is recessed inward. The fixing portion 272A is one of two connecting portions that connect the inner pipe 207 to the inner peripheral surface of the outer pipe 208.

The two recesses 272B and 272C form openings 211A and 211B that allow the second end portion 272 of the inner pipe 207 to communicate with the gap 210, respectively. The fixing portion 272A axially closes the space between the inner pipe 207 and the outer pipe 208 at a portion other than the two recesses 272B and 272C. That is, a part of the fixed portion 272A in the circumferential direction is separated from the inner peripheral surface of the outer pipe 208.

The two recesses 272B and 272C are arranged at positions facing each other with the central axis of the inner pipe 207 interposed therebetween. Further, the radius of curvature R7 of the two recesses 272B and 272C may be substantially the same as the maximum radius of the fixed portion 272A (that is, the radius of the region other than the recesses 272B and 272C) R8. As a result, the circumferential length of the inner pipe 207 and the wall thickness of the inner pipe 207 can be maintained before and after the forming of the recesses 272B and 272C.

As described above, the inner pipe 207 constitutes the first range having the first outer peripheral surface (that is, the region other than the recesses 272B and 272C) and the openings 211A and 211B, and is inside the first outer peripheral surface. It has a second range (ie, recesses 272B, 272C) having a second outer peripheral surface on which it is located.

Further, the inner pipe 207 has a first diameter portion (that is, a second end portion 272) including the first range and the second range, and a second diameter portion (that is, a second diameter portion) having an outer diameter smaller than that of the first diameter portion. It has a portion other than the end portion 272).

(Outer pipe)
As shown in FIG. 11B, the outer pipe 208 is arranged so as to surround the outer peripheral surface of the inner pipe 207. That is, in the outer pipe 208, the inner pipe 207 is arranged on the inner peripheral side, and forms a double pipe together with the inner pipe 207.

The inner diameter of the outer pipe 208 is larger than the outer diameter of the inner pipe 207. The outer diameter in the range forming the gap 210 of the outer pipe 208 (that is, the region between the first end portion 281 and the second end portion 282) is equal to or less than the outer diameter of the second end portion 282. In the present embodiment, the outer tube 208 has a constant diameter in the longitudinal direction.

In the double pipe, one end of the first end and the second end is connected to the first flow path (that is, the pipe material 9A) on the upstream side in the flow direction of the exhaust, and the other end is the exhaust. By connecting to the second flow path (that is, pipe material 9B) on the downstream side in the flow direction of the above, the first exhaust flow path 212 connecting the first flow path and the second flow path via the inner pipe 207 can be configured. be.

The outer pipe 208 has a first end portion 281 and a second end portion 282 connected to the outer peripheral surface of the inner pipe 207, respectively. The diameters of the first end 281 and the second end 282 are equal. The second end 282 of the outer pipe 208 constitutes the end of the sub muffler 203.

Further, a gap 210 is provided between the inner pipe 207 and the outer pipe 208, and at the second end 282, the inner pipe 207 is provided with openings 211A and 211B for connecting to the outer pipe 208, and the gap 210 is opened. It is configured to lead to the first exhaust flow path 212 via 211A and 211B.

An inclusion 209, which will be described later, is arranged inside the first end portion 281. That is, in the vicinity of the first end portion 281, the space between the inner pipe 207 and the outer pipe 208 is blocked by the inclusions 209 sandwiched between the outer peripheral surface of the inner pipe 207 and the inner peripheral surface of the outer pipe 208. ing.

On the other hand, the second end portion 282 is directly fixed by welding to a portion of the outer peripheral surface of the fixing portion 272A of the inner pipe 207 other than the two recesses 272B and 272C. Further, the second end portion 282 of the outer pipe 208 extends axially outward from the second end portion 272 of the inner pipe 207.

That is, in the first range of the inner pipe 207, the outer peripheral surface of the inner pipe 207 and the inner peripheral surface of the outer pipe 208 are in contact with each other, and the inner pipe 207 and the outer pipe 208 are joined to form the inner pipe 207 and the outer pipe 208. The space between the pipe 208 and the pipe 208 is closed. Further, in the second range of the inner pipe 207, a part of the gap 210 is formed between the outer peripheral surface of the inner pipe 207 and the inner peripheral surface of the outer pipe 208.

A resonance chamber 210A corresponding to a part of the void 210 is formed between the outer peripheral surface of the second diameter portion of the inner pipe 207 (that is, a portion other than the second end portion 272) and the inner peripheral surface of the outer pipe 208. Has been done. Further, a resonance tube 210B corresponding to a part of the gap 210 is formed between the second outer peripheral surface of the inner tube 207 (that is, the recesses 272B and 272C) and the inner peripheral surface of the outer tube 208.

The openings 211A and 211B are located at one end of the resonance tubes 210B, and the resonance tubes 210B communicate with the first exhaust flow path 212 through the openings 211A and 211B, and the resonance chamber 210A communicates with the first exhaust flow path through the resonance tubes 210B. By communicating with 212, the resonance tube 210B and the resonance chamber 210A are configured to function as a Helmholtz resonator.

Further, the sub muffler 203 is configured to function as a side branch type silencer by connecting the first exhaust flow path 212 and the void 210 via a plurality of communication holes 273A and 273B.

Further, when air column resonance occurs in the second exhaust flow path composed of the exhaust flow path constituent members including the submuffler 203, openings 211A and 211B are located at positions corresponding to the abdomen of the standing wave generated in the second exhaust flow path. Is placed.

(Intercession)
The inclusions 209 are cushioning materials sandwiched between the outer peripheral surface of the first end portion 271 of the inner pipe 207 and the inner peripheral surface of the first end portion 281 of the outer pipe 208. The inclusion 209 constitutes one of two connecting portions that connect the inner pipe 207 to the inner peripheral surface of the outer pipe 208.

As shown in FIG. 11C, inclusions 209 are arranged along the entire circumferential direction of the outer peripheral surface of the inner pipe 207 and the inner peripheral surface of the outer pipe 208. That is, the inclusions 209 are arranged so as to block the space between the inner pipe 207 and the outer pipe 208 in the axial direction of the inner pipe 207.

The inclusion 209 may be provided with an opening in a part in the circumferential direction as long as the function of the void 10 as a side branch is not lost. By adjusting the size of this aperture, the characteristic frequency of resonance can be adjusted.

The inclusion 209 is not limited as long as it can form a gap 210 as a side branch described later and can slide at least with respect to the inner pipe 207 or the outer pipe 208. As the inclusions 209, a breathable, for example, metal wire mesh is suitable.

(Void)
The gap 210 is a semi-enclosed space defined by the outer peripheral surface of the inner pipe 207, the inner peripheral surface of the outer pipe 208, the fixing portion 272A, and inclusions 209.

The gap 210 communicates with the inside of the inner pipe 207 by the first communication hole 273A and the second communication hole 273B and the two recesses 272B and 272C. The void 210 reduces the volume of a particular frequency. The characteristic frequency of the void 210 can be adjusted by changing the positions of the first communication hole 273A and the second communication hole 273B.

(Relationship between inner pipe, outer pipe, and void)
As shown in FIG. 11B, the cross-sectional area S2 of the void 210 is equal to or less than the cross-sectional area S1 of the hollow portion of the inner pipe 207.

Further, the average wall thickness of the inner pipe 207 (that is, the average thickness of the plate material constituting the inner pipe 207), which may be lower in strength than the outer pipe 208, constitutes the average wall thickness of the outer pipe 208 (that is, the outer pipe 208). The average thickness of the plate material) should be less than or equal to. In the present embodiment, the inner pipe 207 and the outer pipe 208 are arranged so that their central axes coincide with each other, but their central axes do not necessarily have to coincide with each other.

The distance between the end of the gap 210 in the axial direction of the inner pipe 207 and the communication hole closest to this end, and the distance between the communication holes are different from each other. That is, the distance between the first end 271 of the inner pipe 207 and the first communication hole 273A, the distance between the first communication hole 273A and the second communication hole 273B, and the second communication hole 273B and the second communication hole 207. The distances to the end 272 are different from each other. The positions of the inner pipes 207 of the communication holes 273A and 273B in the circumferential direction are not particularly limited.

[2-2. effect]
According to the second embodiment described in detail above, the following effects can be obtained.
(2-2a) Since the side branch type silencer is formed by the void 210 communicating with the first exhaust flow path 212, it is possible to muffle the sound at a plurality of frequencies.

(2-2b) By providing the openings 211A and 211B communicating with the void 210 at the second end portion 272 of the inner pipe 207, it is possible to achieve both muffling by Helmholtz resonance and muffling by side branching.

(2-2c) By providing the plurality of communication holes 273A and 273B at positions separated in the axial direction of the inner pipe 207, a plurality of side branches having different corresponding frequencies can be formed in the gap 210. Therefore, the muffling effect can be exerted for more frequencies.

Here, FIG. 12A shows the configuration of the submuffler 2103 in which a plurality of communication holes corresponding to the communication holes 273A and 273B are not formed, and the sound pressure in the submuffler 2103. FIG. 12B shows a submuffler 203 in which a plurality of communication holes 273A and 273B are formed, and a sound pressure in the submuffler 203.

When air column resonance occurs in the second exhaust flow path, in the submuffler 203 of FIG. 12B, the second communication hole 273B is located on the antinode of the standing wave D1 in the primary mode generated in the exhaust system 201, and the first communication hole 273A is formed. By being located on the antinode of the standing wave D2 in the secondary mode, the muffling effect can be obtained more reliably. For convenience, FIGS. 12A and 12B show the purification device 3, the sub muffler 2103, 203, and the main muffler 7 arranged straight through the pipe material 9, but these components are bent. Even if there is, air column resonance can occur in the second exhaust flow path, so the position corresponding to the antinode of the standing wave is specified, and the first communication hole 273A and the second communication hole 273B are arranged in the same manner as above. The position can be set.

(2-2d) By arranging inclusions 209 between the outer pipe 208 and the inner pipe 207 instead of joining the outer pipe 208 and the inner pipe 207, the thermal expansion of the inner pipe 207 and the outer pipe 208 is performed. When a difference occurs, the outer tube 208 can slide axially with respect to the inner tube 207. Therefore, stress concentration at the connecting portion between the inner pipe 207 and the outer pipe 208 is suppressed. As a result, the occurrence of cracks can be suppressed.

In the second embodiment, the sub mufflers 203 and 213 correspond to the silencer.
[2-3. Deformation example of sub muffler]
(2-3a) The sub muffler 213 shown in FIG. 13 is used in the exhaust system 201 in place of the sub muffler 203 of FIG. The submuffler 213 includes an inner tube 207, an outer tube 208, and inclusions 209. The submuffler 213 has a double tube structure.

Since the inner pipe 207, the outer pipe 208 and the inclusions 209 of the sub muffler 213 are the same as the sub muffler 203 of FIGS. 9A and 9B except for the points described below, detailed description of these members will be given. Omit.

In the sub muffler 213, the second end portion 282 of the outer pipe 208 is welded to the inner pipe 207 over the entire circumference. That is, the inner pipe 207 does not have recesses 272B and 272C at the second end portion 272. The outer shape of the second end portion 272 of the inner pipe 207 is circular.

As described above, unlike the sub muffler 203 of FIGS. 9A and 9B, the sub muffler 213 does not have openings 211A and 211B. Since the resonance tube 210B is not formed in the sub muffler 213, the sub muffler 213 does not function as a Helmholtz resonator, but functions only as a side branch type silencer.

According to such a configuration, since the side branch type silencer is formed by the void 210 communicating with the first exhaust flow path 212, it is possible to muffle the sound at a plurality of frequencies.
(2-3b) In the submuffler 203 of the above embodiment, the inner pipe 207 may have a single communication hole. Further, the inner pipe 207 may have three or more communication holes provided at positions separated from each other in the axial direction of the inner pipe 207.

(2-3c) In the submuffler 203 of the above embodiment, the fixing portion 272A may have a single opening 211B (that is, a recess 272C) as shown in FIG. 14A. Further, the fixing portion 272A may have flat portions 272D, 272E having a chord-shaped cross section shown in FIG. 14B, or convex portions 272F, 272G protruding outward in the radial direction shown in FIG. 14C, instead of the concave portion.

(2-3d) The submuffler 203 of the above embodiment does not necessarily have to include inclusions 209. That is, both of the two connecting portions of the inner pipe 207 may be fixed portions fixed to the inner peripheral surface of the outer pipe 208. Specifically, the first end 271 of the inner pipe 207 may be directly fixed to the first end 281 instead of being connected to the first end 281 of the outer pipe 208 by the inclusions 209. In this case, the gap 210 is defined by the outer peripheral surface of the inner pipe 207, the inner peripheral surface of the outer pipe 208, and two fixing portions.

(2-3e) In the submuffler 203 of the above embodiment, inclusions may be sandwiched between the second end portion 272 of the inner pipe 207 and the second end portion 282 of the outer pipe 208. That is, the space between the inner pipe 207 and the outer pipe 208 may be blocked by sandwiching the inclusions between the outer peripheral surface of the inner pipe 207 and the inner peripheral surface of the outer pipe 208.

(2-3f) In the submuffler 203 of the above embodiment, the outer diameter in the range forming the gap 210 of the outer pipe 208 does not necessarily have to be equal to or less than the outer diameter of the second end portion 282. Further, the cross-sectional area of the void 210 does not necessarily have to be less than or equal to the cross-sectional area of the hollow portion of the inner pipe 207.

[2-4. Example]
Next, a comparison between Examples 1 and 2 and Comparative Example 1 performed to confirm the effect of the second embodiment will be described.

In Comparative Example 1, in the submuffler 203 of FIG. 9B, the communication hole of the inner pipe 207 is eliminated. In the first embodiment, the number of communication holes of the inner pipe 207 is one in the submuffler 203 of FIG. 9B. The second embodiment is the submuffler 203 of FIG. 9B in which the inner pipe 207 has two communication holes. The relationship between the frequency (horizontal axis) and the muffling volume (vertical axis) in Comparative Example 1 and Examples 1 and 2 is shown in FIGS. 15A, 15B and 15C.

In Comparative Example 1, the void 210 functions as a resonance chamber connected to the inner tube 207. Therefore, as shown in FIG. 15A, there is only one muffling frequency (that is, muffling peak).

On the other hand, in the first embodiment, as shown in FIG. 15B, since the void 210 functions as a side branch, the sound deadening effect can be exhibited for a plurality of frequencies. In the lowest frequency band (far left in the graph) in FIG. 15B, the muffling effect by Helmholtz resonance and the muffling effect by side branch are combined.

Further, by increasing the number of communication holes of the inner tube 207, as shown in FIG. 15C, the frequency at which the sound deadening effect is produced can be increased.
[3. 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 various forms can be adopted.

(3a) In the above embodiment, the sub-mufflers 5, 203 are arranged only on the right side of the vehicle battery 200 in the left-right direction of the vehicle, but the arrangement of the sub-mufflers and the number of sub-mufflers are not limited thereto. For example, the sub muffler may be arranged only on the left side of the vehicle battery in the left-right direction of the vehicle. Further, for example, the exhaust system may include two sub mufflers, and one sub muffler may be arranged on the right side and the left side of the vehicle battery in the left-right direction of the vehicle.

(3b) In the above embodiment, in the purification device 3, the second connection portion 334 in which the second purification member 32 is housed extends in the left-right direction of the vehicle along the front surface of the case in which the vehicle battery 200 is housed. Is located in. However, the arrangement of the purification device 3 on the front side of the vehicle battery 200 is not limited to this. For example, as shown in FIG. 16, in the purification device 3, the first connection portion 332 in which the first purification member 31 is housed extends in the left-right direction of the vehicle, and the second connection in which the second purification member 32 is housed. The unit 334 may be arranged so as to extend in the front-rear direction of the vehicle. In FIG. 16, only the arrangement of the purification device 3 is changed, and since each component has the same configuration as that of the above embodiment, the same symbols as those of the above embodiment are used.
Further, for example, the purification device 3 may be arranged so that the first connection portion 332 extends in the vertical direction of the vehicle and the second connection portion 334 extends in the front-rear direction or the left-right direction of the vehicle. Further, for example, the purification device 3 may be arranged so that the first connecting portion 332 extends in the front-rear direction or the left-right direction of the vehicle, and the second connecting portion 334 extends in the vertical direction of the vehicle.

(3c) In the above embodiment, in the bending portion 333 of the purification device 3, the direction of the flow path 20 in the first connection portion 332 and the direction of the flow path 20 in the second connection portion 334 are orthogonal to each other in the bending portion 333. The configuration which is bent in an L shape is shown. However, the bent portion is not limited to the above-mentioned L-shaped bending configuration. For example, the bent portion may be bent at a predetermined angle such that the direction of the flow path in the first connecting portion and the direction of the flow path in the second connecting portion intersect.

(3d) In the above embodiment, in the purification device 3, the first purification member 31 and the second purification member 31 so that the exhaust flow path bends in an L shape from the first purification member 31 to the second purification member 32. The purification member 32 is arranged. However, the arrangement of the first purification member 31 and the second purification member 32 is not limited to this. For example, the first purification member 31 and the second purification member 32 may be arranged in a straight line so that their central axes coincide with each other. In this case, the casing forming the accommodation chamber does not have to have a bent portion.

(3e) In the above embodiment, the submufflers 5, 203 are formed in a straight line, but the shape of the submuffler is not limited to this. For example, as shown in FIG. 17, the sub muffler 50 may be bent. The sub muffler 50 is easier to bend than the sub muffler having a configuration in which a gap is secured only by inflating the outer pipe to the outer peripheral side. In this case, the sub muffler 50 may be arranged so that the bent portion of the sub muffler 50 is aligned with the corner portion of the case in which the vehicle battery 200 is housed. In FIG. 17, only the configuration of the submuffler 50 is changed, and the other components have the same configuration as that of the above embodiment. Therefore, the same symbols as those of the above embodiment are used for the other components.

(3f) In the above embodiment, the purification device 3 includes a first purification member 31 and a second purification member 32, but the number of purification members is not limited to this. For example, the purification device may include a third purification member in addition to the first purification member 31 and the second purification member 32.

(3g) The functions of one component in the above embodiment may be dispersed as a plurality of components, or the functions of the plurality of components may be integrated into one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other embodiment.

1,201 ... Exhaust system, 3 ... Purification device, 5,50,51,61,76,81,86,91,203,213 ... Submuffler, 11,207 ... Inner pipe, 13,208 ... Outer pipe, 15 ... Double pipe, 30 ... storage room, 31 ... first purification member, 32 ... second purification member, 100 ... engine, 200 ... vehicle battery.

Claims (7)

An exhaust system in which a vehicle battery is mounted on a vehicle provided under the floor to form an exhaust flow path for exhaust gas exhausted from an internal combustion engine.
One that houses the first purification member and the second purification member arranged so that the flow of the exhaust gas is in series in the exhaust flow path, and the first purification member and the second purification member. With a containment chamber, with a purification device,
A silencer located downstream of the purification device and having an inner pipe through which the exhaust gas passes and an outer pipe forming a double pipe together with the inner pipe.
With
The purification device is arranged on the front side of the vehicle battery in the front-rear direction of the vehicle.
An exhaust system in which the silencer is arranged on at least one of the left side and the right side of the vehicle battery in the left-right direction of the vehicle. The exhaust system according to claim 1.
The purification device is an exhaust system in which the first purification member and the second purification member are arranged so that the exhaust flow path bends from the first purification member to the second purification member. The exhaust system according to claim 2.
In the purification device, the first purification member and the second purification member are arranged so that the exhaust flow path bends in an L shape from the first purification member to the second purification member. , Exhaust system. The exhaust system according to any one of claims 1 to 3.
In the double pipe of the silencer, one of the first end portion and the second end portion is on the upstream side of the exhaust flow path, and the other is on the downstream side of the exhaust flow path. , A part of the exhaust flow path is formed through the inner pipe.
A gap is provided between the inner pipe and the outer pipe, an opening is provided between the inner pipe and the outer pipe at the second end portion, and the gap is exhausted through the opening. It is configured to lead to the flow path,
With reference to the position of the inner surface of the outer pipe, the inner pipe has a first range in which the outer surface of the inner pipe is at the same position as the reference and the outer surface of the inner pipe is inside the reference. Has a second range to be placed and
The outer surface of the inner tube reaches the second end in each of the first range and the second range.
In the first range, the inner pipe and the outer pipe are arranged so that the inner pipe and the outer pipe are arranged at positions where the outer surface of the inner pipe and the inner side surface of the outer pipe are in contact with each other. It is configured to be closed between the pipes
In the second range, a part of the gap is formed between the outer surface of the inner tube and the inner surface of the outer tube, and the opening is formed at a position where the second range reaches the second end. The exhaust system that is configured. The exhaust system according to any one of claims 1 to 3.
In the double pipe of the silencer, one of the first end portion and the second end portion is on the upstream side of the exhaust flow path, and the other is on the downstream side of the exhaust flow path. , A part of the exhaust flow path is formed through the inner pipe.
A gap is provided between the inner pipe and the outer pipe, an opening is provided between the inner pipe and the outer pipe at the second end portion, and the gap is exhausted through the opening. It is configured to lead to the flow path,
The inner pipe has the inclusions based on the position of the inner side surface of the inclusions in the circumferential range in which the inclusions sandwiched between the outer surface of the inner pipe and the inner side surface of the outer pipe exist. In the circumferential range, the position of the inner surface of the outer pipe is used as a reference, and the first range in which the outer surface of the inner pipe is at the same position as the reference and the outer surface of the inner pipe are inward of the reference. Has a second range to be placed and
The outer surface of the inner tube reaches the second end in each of the first range and the second range.
In the first range, the inclusions are sandwiched between the outer surface of the inner pipe and the inner surface of the outer pipe, so that the space between the inner pipe and the outer pipe is closed. Being done
In the second range, a part of the gap is formed between the outer surface of the inner tube and the inner surface of the outer tube, and the opening is formed at a position where the second range reaches the second end. The exhaust system that is configured. The exhaust system according to claim 4 or 5.
The inner pipe has a large diameter portion having a first diameter and a small diameter portion having a second diameter smaller than the first diameter.
A resonance chamber corresponding to a part of the void is formed between the outer surface of the small diameter portion and the inner surface of the outer tube.
The large-diameter portion is arranged at the second end portion, and the large-diameter portion has the first range and the second range, and in the second range, the outer surface of the large-diameter portion and the outer pipe. A resonance tube corresponding to a part of the void is formed between the inner surface and the inner surface of the space.
The resonance tube has an opening at one end, the resonance tube communicates with the exhaust flow path through the opening, and the resonance chamber communicates with the exhaust flow path through the resonance tube. An exhaust system in which the resonator tube and the resonance chamber are configured to function as a Helmholtz resonator. The exhaust system according to any one of claims 4 to 6.
An exhaust system in which the outer diameter within the range from the first end portion to the second end portion of the outer pipe is equal to or less than the outer diameter of the outer pipe at the second end portion.

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