JP2001207843A - Exhaust gas pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas pipe that can effectively cool not only exhaust gas in the pipe periphery region but also exhaust gas in the pipe center region. SOLUTION: The exhaust gas pipe comprises a pipe body 1 and a partitioning part 2 that partitions the hollow of the pipe body 1 into a plurality of sections in the axial view. The periphery of the pipe body 1 has heat radiating fins 3 extending along the junctions between the pipe body 1 and the partitioning part 2 to thus efficiently diffuse the heat of exhaust gas that the partitioning part absorbs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas pipe provided in an exhaust system of an automobile or the like, and more particularly, to a technique for improving an exhaust gas cooling effect.

[0002]

2. Description of the Related Art Conventionally, exhaust gas discharged from an engine of an automobile or the like is sent to one or more mufflers provided behind a vehicle body by an exhaust gas pipe, where the exhaust noise is reduced and discharged to the outside. . Here, it is known that the noise attenuation characteristics of the silencer decrease when the exhaust gas temperature is high. Therefore, in order to reduce the size and weight of the muffler, it is desirable to lower the exhaust gas temperature before the muffler.

[0003] As an exhaust gas pipe having a function of cooling exhaust gas, there is known an exhaust gas pipe provided with cooling fins on the outer periphery of the exhaust gas pipe, for example, as disclosed in Japanese Utility Model Laid-Open No. 18319/1987. .

[0004]

However, in a configuration in which cooling fins are simply provided on the outer periphery of the exhaust gas pipe, the exhaust gas near the wall of the exhaust pipe is cooled, but the exhaust gas at the center of the pipe away from the wall is effectively used. There was a problem that cooling was not possible. Accordingly, an object of the present invention is to provide an exhaust gas pipe capable of effectively cooling not only the exhaust gas at the outer peripheral portion of the exhaust gas pipe but also the exhaust gas at the center of the pipe.

[0005]

An exhaust gas pipe according to the present invention comprises a pipe body, and a partition for dividing a hollow portion of the pipe body into a plurality of parts as viewed in the axial direction. A radiation fin is provided extending along a joint between the main body and the partition.

In the exhaust gas pipe configured as described above, the heat of the exhaust gas in the central portion of the pipe is absorbed by the partition. The heat absorbed by the partition is conducted to the radiation fins provided along the partition, and is radiated from the radiation fins to the outside air. Therefore, the heat of the exhaust gas at the center of the pipe can be efficiently dissipated. In addition, since the heat capacity of the exhaust pipe increases due to the presence of the partition, and the heat radiation fins also dissipate the heat of the pipe outer periphery, the exhaust gas can be cooled more efficiently.

[0007] In order to efficiently dissipate the heat absorbed by the partition from the radiating fin, it is desirable that no boundary surface of the material exists between the partition and the radiating fin or the pipe body.
For example, even if the partition and the radiating fin are welded to each other to completely melt the joint, a boundary surface of the heat-affected zone of welding occurs, which lowers the efficiency of heat conduction. Therefore, from the viewpoint of cooling efficiency, it is most desirable to form the pipe body, the partition portion, and the radiating fin from one material without a seam by, for example, drawing. However, the following configuration is preferable from the viewpoint of a balance between manufacturing cost and cooling efficiency.

For example, one plate is bent in a substantially S-shape while leaving a flange portion on both sides, a partition portion is formed by a central plate portion, a radiation fin is formed by the flange portion, and a radiating fin is formed by the remaining plate portions. You may comprise a pipe main body. According to such a configuration, the number of seams between the partition portion, the pipe body, and the radiating fins can be reduced, so that the thermal conductivity is good and the cooling efficiency is excellent.

In addition, the partition portion may be formed of a partition plate separate from the pipe main body, and both side portions of the partition plate may protrude from the pipe main body in the radial direction to form heat radiation fins. According to such a configuration, the heat absorbed by the partition plate is immediately transmitted to the radiation fins and dissipated, so that the cooling efficiency is improved.

In this case, both circumferential sides of the pipe body are fixed to the partition plate by appropriate means such as welding. At this time, the edge of the pipe main body can be fixed by abutting against the partition plate. However, it is preferable to form flange portions on both circumferential sides of the pipe main body and fix the flange portion to the partition plate. With such a configuration, the pipe body and the partition plate are joined to each other over a wide area, so that the heat conductivity from the pipe body to the partition plate is improved.

The flanges formed on both sides of the pipe body can be bent outward. Thereby, the flange portion functions as a radiation fin. In that case, the edge of the flange may be extended to the edge of the radiation fin so that the flange almost completely overlaps the radiation fin, and the edge of the radiation fin may be extended from the flange of the pipe body. You may make it protrude. The former is suitable when it is desired to particularly improve the cooling efficiency of the pipe body since the width of the flange portion is wide.

Further, the flanges formed on both sides of the pipe body can be bent inward. With this configuration, the radiating fins are completely exposed from the outer periphery of the pipe main body, and thus are particularly suitable in a case where the radiating fins cannot be enlarged due to a limited space.

The partition and the radiation fin are preferably provided so as to form a spiral along the axial direction. This facilitates the wind hitting the radiating fins while the vehicle is running, thereby promoting the dissipation of heat from the radiating fins. Further, since the exhaust gas flow easily hits the partition, absorption of heat from the exhaust gas is promoted. Therefore, the cooling efficiency of the exhaust gas pipe can be further improved.

In the present invention, by providing the partition in the pipe body, the heat capacity for storing the heat of the exhaust gas can be increased. From this point of view, it is preferable that the partition portion is composed of a plurality of plate portions rather than a single plate portion. For example, the partition portion may be formed such that three plate portions are radial when viewed in the axial direction, and the inside of the pipe body may be divided into three. Alternatively, four or more plates may be radial.

If the resistance between the exhaust gas and the partition portion is large, turbulence tends to occur in the exhaust gas flow, and the exhaust gas is mixed to improve the cooling efficiency. Therefore, it is possible to provide unevenness or holes in the partition, or to form the partition so as to undulate in the exhaust direction.

[0016]

DETAILED DESCRIPTION OF THE INVENTION 1. First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing a part of an exhaust gas pipe of the first embodiment, and reference numeral 1 in the figure denotes a cylindrical pipe main body. In a hollow portion of the pipe main body 1, a partition portion 2 for bisecting a cross section is formed. Further, on the outer periphery of the pipe main body, a radiation fin 3 extending in the axial direction along the edge of the partition 2 is formed. In this exhaust gas pipe, the pipe body 1, the partition 2 and the heat radiation fins 3 are formed by pulling out from one material.

In the exhaust gas pipe having the above structure, the heat of the exhaust gas at the center of the pipe is absorbed by the partition 2 and the heat absorbed by the partition 2 is transmitted to the radiation fins 3 and radiated to the outside air. You. Therefore, the heat of the exhaust gas at the center of the pipe can be efficiently dissipated. In particular, in the first embodiment, since there is no seam between the partition portion 2, the radiation fins 3, and the pipe main body 1, the heat conductivity between the members is good, and the cooling efficiency can be greatly improved. it can.

[0018] 2. Second Embodiment FIG. 2 shows a second embodiment of the present invention. In the figure, reference numeral 11 denotes a pipe main body, which has a shape obtained by substantially halving a cylinder. On both circumferential sides of the pipe body 11,
The flange portions 11a obtained by bending the portions outward are formed so as to be located on the same plane. The two pipe bodies 11 are fixed so as to sandwich the partition plate 12, thereby forming a substantially cylindrical exhaust gas pipe.

Both side portions of the partition plate 12 project radially from the cylindrical portion of the pipe body 11, and the projected portions serve as radiation fins 13. Further, the width of the partition plate 12 is the same as the dimension between both edges of the flange portion 11a of the pipe main body 11, whereby the flange portion 11a of the pipe main body 11 almost completely overlaps with the radiation fins 13.

In the exhaust gas pipe configured as described above, the heat absorbed by the partition plate 12 is immediately transmitted to the radiation fins 13 and dissipated, so that the cooling efficiency can be improved. Further, since the flange portion 11a of the pipe main body 11 functions as a radiation fin, the cooling efficiency of the pipe main body 11 can be improved.

Modification Example 1 FIG. 3 is a view showing a modification example of the second embodiment, and shows an example in which a part of the radiation fins 13 protrudes from the flange portion 11a of the pipe body 11. In this modified example, since a part of the radiation fins 13 is exposed, the cooling efficiency of the partition plate 12 is improved as compared with the second embodiment. However, since the pipe main body 11 and the partition plate 12 are joined with a large area of the flange portion 11a, the cooling efficiency of the pipe main body 11 is sufficient.

Modification 2 FIG. 4 shows another modification of the second embodiment. The exhaust gas pipe shown in this figure is different from the above in that the flange portion 11b of the pipe body 11 is bent inward. In such a configuration, the heat radiation fins 13 are completely exposed from the outer periphery of the pipe main body 11, and thus are particularly suitable for a case where the heat radiation fins 13 cannot be enlarged due to a limited space.

[0023] 3. Third Embodiment FIG. 5 shows a third embodiment of the present invention. In this embodiment, the partition part 22 in the pipe main body 21 is formed by arranging four plate parts 22a in a cross shape. Also,
The radiating fins 23 are provided on the radial extension of each plate portion 22a. In such an exhaust gas pipe, since the heat capacity of the partition 22 for absorbing the heat of the exhaust gas is large, the cooling efficiency can be further improved. In this modification, the number of the plate portions 22a is four, but it can be three or five or more.

[0024] 4. Fourth Embodiment FIGS. 6 and 7 show a fourth embodiment of the present invention. In this embodiment, as shown in FIG. 6, both sides of one plate are bent at right angles to opposite sides to form a flange portion, and a portion between the flange portions is bent in a substantially S shape. As a result, two pipe bodies 31 each having a half of a cylinder, a partition portion 32, and a radiation fin 33 are formed. The exhaust gas pipe shown in FIG. 7 is formed by welding the corners of the pipe body 31 and the radiation fins 33 to the corners of the pipe body 31 and the partition 32.

According to the exhaust gas pipe having the above structure, the heat of the exhaust gas is absorbed by the partition 32, and the heat is radiated from the radiation fins 33 together with the heat absorbed by the pipe body 31. At this time, the number of joints in the heat conduction path is smaller than in the case where a plurality of plates are joined, so that the heat conductivity is high, and thus the cooling efficiency can be increased. In addition, there is an advantage that the material yield is good because it can be constituted by one plate, and that the production is easy because there is only one component.

[0026] Modification Next, FIG. 8 shows a modification of the fourth embodiment.
This modification is different from the fourth embodiment in that the partition 42 and the radiation fin 43 are spirally formed in the axial direction. Such an exhaust gas pipe can be manufactured by twisting both ends of the pipe main body 41 in the circumferential direction from the state shown in FIG. In such an exhaust gas pipe, the wind easily hits the radiating fins 43 while the vehicle is running, so that heat dissipation from the radiating fins 43 is promoted. Further, since the exhaust gas flow easily hits the partition portion 42, absorption of heat from the exhaust gas is promoted. Therefore, the cooling efficiency of the exhaust gas pipe can be further improved.

[0027]

As described above, in the present invention,
A pipe main body, and a partition part for dividing a hollow portion of the pipe main body into a plurality of parts as viewed in the axial direction, and a heat radiation extending along a joint between the pipe main body and the partition part on an outer peripheral part of the pipe main body. Since the fins are provided, it is possible to effectively cool not only the exhaust gas at the outer peripheral portion of the exhaust gas pipe but also the exhaust gas at the center of the pipe.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an exhaust gas pipe according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an exhaust gas pipe according to a second embodiment of the present invention.

FIG. 3 is a perspective view showing a modified example of the exhaust gas pipe of the second embodiment of the present invention.

FIG. 4 is a perspective view showing another modification of the exhaust gas pipe according to the second embodiment of the present invention.

FIG. 5 is a perspective view showing an exhaust gas pipe according to a third embodiment of the present invention.

FIG. 6 is a front view showing a state where a plate is bent in an exhaust gas pipe according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view showing an exhaust gas pipe according to a fourth embodiment of the present invention.

FIG. 8 is a perspective view showing a modification of the exhaust gas pipe according to the fourth embodiment of the present invention.

[Explanation of symbols]

 1, 11, 21, 31, 41 Pipe body 2, 12, 22, 32, 42 Partition plate (partition portion) 3, 13, 23, 33, 43 Radiation fin

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshihiko Eguchi 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 3D038 BA06 BB01 3G004 AA01 DA01 EA06 GA06 3G091 AA02 BA36 FB03

Claims (5)

[Claims] 1. A pipe main body, and a partition portion for dividing a hollow portion of the pipe main body into a plurality of parts as viewed in an axial direction, and a joint portion between the pipe main body and the partition portion is provided on an outer peripheral portion of the pipe main body. An exhaust gas pipe provided with heat radiation fins extending along. 2. A single plate is bent in a substantially S-shape while leaving flange portions on both sides, and the central plate portion constitutes the partition portion and the flange portion constitutes the radiation fins.
The exhaust gas pipe according to claim 1, wherein the pipe body is constituted by a remaining plate portion. 3. The radiating fin is formed by forming the partition portion with a partition plate separate from the pipe main body and projecting both side portions of the partition plate in the radial direction from the pipe main body. The exhaust gas pipe according to claim 1, wherein 4. The exhaust gas pipe according to claim 3, wherein flange portions are formed on both circumferential sides of the pipe body, and the flange portions are fixed to the partition plate. 5. The exhaust gas pipe according to claim 1, wherein the partition portion and the radiating fins are provided so as to form a spiral along the axial direction.