JPH11303633A - Beat reservation type exhaust pipe of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely absorb an axial thermal elongation difference between both inner and outer pipes in a heat reservation type exhaust pipe comprising an inner pipe and an outer pipe, each end of which is mutually fixed by installing a mesh member slidably supporting the outer peripheral surface of the inner pipe in an annular recessed part formed in the inner peripheral surface of the other end of the outer pipe. SOLUTION: A four-cylinder engine includes four exhaust single pipes 51 -54 communicating with four exhaust ports, which are formed by an inner single pipe 10 and an outer single pipe 11. Further, the engine includes exhaust collecting pipes 61 , 62 connecting two exhaust single pipes 51 -54 to each other into one pipe, which are also formed by an inner collecting pipe 15 and an outer collecting pipe 16. In this case, an annular recessed part 21 is formed in the inner peripheral surface of the downstream end in the outer collecting pipe 16. An annular two-split mesh member 20 formed by knitting a stainless steel wire, for example, that is, a pair of mesh half bodies are slidably installed in the annular recessed part 21, and the downstream end of the inner collecting pipe 15 is slidably fitted to the inner peripheral surface of each mesh half body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner tube and an outer tube, which are arranged in a double manner, and one end of which is fixed to each other.
The present invention relates to an improvement in a warm exhaust pipe of an engine including an exhaust manifold having an annular mesh member interposed between the other end portions thereof to enable relative sliding therebetween.

[0002]

2. Description of the Related Art An annular mesh member in such a heat-insulating exhaust pipe secures a heat insulating space between an inner pipe and an outer pipe, and reduces a difference in thermal expansion between the inner pipe and the outer pipe due to exhaust gas in the axial direction. It has the function of absorbing and suppressing the vibration of the free end of the inner tube.

[0003] Conventionally, as a structure for holding a mesh member in such a heat retaining type exhaust pipe, a mesh member welded to the inner peripheral surface of an outer pipe (for example, Japanese Patent Laid-Open No. 9-280).
No. 046) and a mesh member fixedly held in an annular groove formed in the inner peripheral surface of the outer tube (Japanese Utility Model Laid-Open No.
129830).

[0004]

In any of the above-mentioned conventional devices, the mesh member is fixed to the outer tube, so that only the inner peripheral surface of the mesh member serves as a sliding surface and slides relative to the outer peripheral surface of the inner tube. It can move. Therefore, the difference in the thermal expansion between the inner pipe and the outer pipe due to the exhaust gas is absorbed only by the sliding between the inner peripheral surface of the mesh member and the outer peripheral surface of the inner pipe. If foreign matter such as enters the slide pipe, the sliding is immediately inhibited, and thermal distortion occurs in each part of the exhaust pipe, which may impair its durability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it has been made possible to use both the inner and outer peripheral surfaces of an annular mesh member as sliding surfaces so that one of the sliding surfaces can be used. Even if a sliding failure occurs, the relative displacement between the inner pipe and the outer pipe is not hindered, and the difference in thermal expansion in the axial direction between the two pipes can be reliably absorbed. The purpose is to provide.

[0006]

In order to achieve the above object, the present invention is to fix one end of an inner tube and an outer tube which are arranged inside and outside doubly, and to connect them between the other ends. In an insulated exhaust pipe of an engine, in which an annular mesh member capable of relative sliding is interposed, an outer peripheral surface of the inner pipe is slid into an annular recess formed in an inner peripheral face of the other end of the outer pipe. A first feature is that a mesh member movably supported is slidably mounted.

According to the first feature, since both the inner peripheral surface and the outer peripheral surface of the annular mesh member serve as sliding surfaces, when a difference in thermal expansion between the inner pipe and the outer pipe in the axial direction occurs, Sliding occurs between the inner tube and the mesh member and between the outer tube and the mesh member, thereby absorbing the difference in thermal elongation.
Therefore, even if a sliding defect occurs due to foreign matter being caught in one of the sliding portions, the difference in thermal expansion can be absorbed without any trouble by the operation of the other sliding portion. Durability can be improved.

In addition, when the two sliding portions operate normally, the difference in thermal expansion between the inner tube and the outer tube in the axial direction is shared by the two sliding portions. Can be reduced by half as compared with the conventional case having only one sliding portion, which can contribute to the improvement of the durability of the mesh member.

Further, the present invention provides an upper flange, a plurality of exhaust single tubes connecting each upstream end to the upper flange,
An engine having an exhaust manifold connected to the downstream end of these exhaust pipes and a lower flange connected to the downstream end of the exhaust manifold, and each pipe having a double wall. In a warmed exhaust manifold, the exhaust manifold is
It consists of an inner collecting pipe and an outer collecting pipe which are arranged inside and outside. The upstream ends of these inner and outer collecting pipes are fixed to each other and fixed to the exhaust pipe, and the downstream end of the outer collecting pipe. An annular mesh member that slidably supports the outer peripheral surface of the inner collecting pipe is slidably mounted in an annular concave portion formed in the inner peripheral surface of the inner collecting pipe, and the lower flange is attached to a downstream end of the outer collecting pipe. The combination is a second feature.

According to the second feature, the difference in thermal expansion between the inner single pipe and the outer single pipe in the axial direction is absorbed by sliding between the inner single pipe and the mesh member, and between the outer single pipe and the mesh member. can do. Therefore, even if a sliding failure occurs due to foreign matter being caught in one of the sliding parts, the difference in the thermal expansion in the axial direction can be absorbed without any trouble by the operation of the other sliding part. The durability of the exhaust manifold can be improved.

In addition, when the two sliding portions operate normally, the difference in the thermal expansion between the inner tube and the outer tube in the axial direction is shared by the two sliding portions. Can be reduced by half as compared with the conventional case having only one sliding portion, which can contribute to the improvement of the durability of the mesh member.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on embodiments of the present invention shown in the accompanying drawings.

FIG. 1 is a side view of an engine provided with a warmed exhaust manifold according to a first embodiment of the present invention, and FIG.
FIG. 3 is a perspective view of the exhaust manifold, FIG. 3 is a partially longitudinal front view of the exhaust manifold, FIG.
5 is a sectional view taken along line 5-5 in FIG. 1, FIG. 6 is a sectional view taken along line 6-6 in FIG. 5, and FIG. 7 is a vertical sectional front view of an exhaust manifold showing a second embodiment of the present invention.

First, a description will be given of a first embodiment of the present invention with reference to FIGS.

In FIG. 1, the cylinder of a four-cylinder engine E is
At the front of the dahead 1, four exhaust ports corresponding to the cylinder
Port 2₁~ 2_FourAre open and these exhaust ports 2₁
~ 2 _FourInsulation of the present invention for inducing exhaust gas discharged from
Exhaust manifold M as a mold exhaust pipe has multiple studs
Attached to cylinder head 1 with bolts 3 and nuts 4
Can be

[0016] As shown in FIGS. 2 to 4, the exhaust manifold M includes a four exhaust monotube 5 ₁ to 5 ₄ of which communicates separately with the four exhaust ports _{21 to 24} of ,
These are referred to as first to fourth exhaust single tubes from the left side in FIG.

The upper flange 7 is connected to the first to the upstream end of the fourth exhaust monotube 5 ₁ to 5 _4, first at the downstream end of the second and third exhaust monotube 5 _2, 5 ₃ exhaust collecting pipe ₆₁ is connected, the second to the downstream end of the first and fourth exhaust monotube 5 ₁ 5 ₄
Exhaust collecting pipe 6 ₂ are connected. The lower flange 8 is connected to the downstream end of the first and second exhaust manifolds 6 ₁ , 6 ₂ . The upper flange 7 is fixed to the cylinder head 1 by the stud bolts 3 and the nuts 4, and the lower flange 8 is connected to a common catalytic converter (exhaust gas purifier) (not shown) arranged under the floor of the vehicle. The intermediate exhaust pipe 21 is connected. The above-mentioned catalytic converter can be directly connected to the lower flange 8.

[0018] Each exhaust monotube 5 ₁ to 5 _4, made of an inner monotube 10 and the outer single tube 11 was placed inside and outside double, cylindrical insulation space is between the inner and outer monotube 10,11 12 are formed. The inner single pipe 10 is made of a thin stainless steel pipe, and the outer single pipe 11 is also made of a stainless steel pipe, but is thicker than the inner single pipe 10.

The upstream end of the outer tube 11 is connected to the inner tube 1
The diameter is reduced so as to fit the outer peripheral surface of the upstream end of the
The upstream end of the upper flange 7 is the corresponding exhaust port.
To 2 ₁~ 2_FourThrough hole 13 connected to₁~ 13_FourMated to
With the through hole 13₁~ 13_FourBy welding on the inner peripheral surface of
It is fixed (see FIG. 4).

At the downstream end of the inner single tube 10, there is formed an annular projection 14 having an arc-shaped cross section which rises to the outer peripheral surface due to the diameter expansion from the inner peripheral side.
1 is slidably fitted to the inner peripheral surface. Thus, the downstream end of the inner single pipe 10 is slidably supported by the outer single pipe 11.

Each of the exhaust manifolds 6 ₁ , 6 ₂ is composed of an inner manifold 15 (inner pipe) and an outer manifold 1 that are arranged inside and outside.
6 (outer tube), the inner and outer collecting tubes 1
A heat insulating space 17 is also formed in 5 and 16. Inner collecting pipe 1
Reference numeral 5 denotes a structure in which opposing ends of a pair of inner collecting pipe halves 15a and 15b made of a thin stainless steel plate are overlapped with each other, and the entire overlapped portion is welded. At that time, the inner collecting pipe 1
5 are formed at the upstream end thereof with two corresponding outer single tubes 11, 11.
Is inserted at the downstream end.

The outer collecting pipe 16 is also formed by overlapping opposing ends of a pair of outer collecting pipe halves 16a and 16b made of a stainless steel plate, and welding the entire overlapping portion. Is thicker than the inner collecting pipe 15. At the upstream end of the outer collecting pipe 16, outer bifurcated pipes 19, 19 respectively covering the inner bifurcated pipes 18, 18 are formed. The distal ends of the outer bifurcated pipes 19, 19 are
The outer diameters of the outer single tubes 11 and 11 are fixed to each other by welding.

As shown in FIG. 5 and FIG.
The lower flange 8 is fixed to a downstream end of the lower flange 6 by welding. An annular concave portion 21 is formed on the inner peripheral surface of the downstream end portion of the outer collecting pipe 16, and an annular split mesh member 20 formed by knitting a stainless steel wire into the annular concave portion 21, that is, a pair of mesh half bodies 20a, 20b is slidably mounted, and the downstream end of the inner collecting pipe 15 is slidably fitted to the inner peripheral surfaces of the mesh halves 20a and 20b.

At this time, a pair of mesh halves 20a, 20
b, the inner collecting pipe half 1 constituting the inner collecting pipe 15
5a, 15b weld 22 and outer collecting pipe half 16a,
16b welding part 23 is arranged. Thus, by sequentially inserting the pair of mesh halves 20a and 20b into the annular concave portion 21, the mesh member 20 can be easily mounted on the outer collecting pipe 16, and furthermore, the mesh halves 2a and 20b can be easily inserted.
By interposing a weld 22 protruding outwardly of the inner collecting pipe halves 15a and 15b between 0a and 20b, interference between the weld 22 and the mesh member 20 is avoided, and each mesh half 20a, Unnecessary rotation of 20b can be restrained.

Next, the operation of the first embodiment will be described.

[0026] During operation of the engine E, an exhaust port 2 ₁ of the exhaust gas is four, ₂ 2, 2 _4, 2 ₃ from the first exhaust monotube 5 _1,
Second exhaust monotube 5 _2, fourth exhaust monotube 5 _4, the third exhaust monotube 5
_It is sequentially discharged to ₃ . The exhaust gas which has passed through the first and fourth exhaust monotube 5 _1, 5 ₄ merged in the first exhaust collecting pipe _61, which has passed through the second and third exhaust monotube 5 _2, 5 ₃ and the second merge at an exhaust merging pipe 6 _2, then, the exhaust gas while further merges with the intermediate exhaust pipe 21, is guided to a common catalytic converter (not shown) to be purified.

By the way, the exhaust monotube 5 ₁ to 5 ₄ are composed of an inner monotube 10 and the outer single tube 11 of the inner and outer double arrangement,
The inner single tube 10 is formed to be thin, and a heat insulating space 12 is formed between the inner and outer single tubes 10 and 11.
Each of the exhaust manifolds 6 ₁ , 6 ₂ is also composed of an inner manifold 15 and an outer manifold 16 in a double inner / outer arrangement. The inner manifold 15 is formed to be thin, and the inner and outer manifolds 15, 16 are formed. The heat insulating space 17 is also formed between the inner single pipe 10 and the inner collecting pipe 15 having a small heat mass.
It is heated by the high-temperature exhaust gas flowing through the inside thereof and quickly rises in temperature, and this is kept warm by the heat insulating spaces 12 and 17. Therefore, the subsequent exhaust gas can be guided to the catalytic converter while suppressing its temperature decrease, thereby promoting its activation and improving the purification efficiency of the exhaust gas.

[0028] Meanwhile, in the exhaust monotube 5 ₁ to 5 _4, the thermal expansion of greater axial than the outer single tube 11 side inside the single tube 10 is caused, downstream of the inner monotube 10 along with its elongation The annular projection 14 on the outer peripheral surface of the side end slides on the inner peripheral surface of the outer single tube 11 supporting the same, and the inner and outer single tubes 1 are moved.
The difference in thermal expansion in the axial direction of 0, 11 is absorbed.

In each of the exhaust manifolds 6 ₁ and 6 ₂ ,
Thermal expansion in the axial direction of the inner collecting pipe 15 is larger than that of the outer collecting pipe 16, and the downstream end of the inner collecting pipe 15 slides with respect to the outer collecting pipe 16 via the mesh member 20 with the expansion. Then, the difference in the thermal expansion between the inner and outer collecting pipes 15, 16 in the axial direction is absorbed.

It should be noted that both the inner and outer peripheral surfaces of the annular mesh member are sliding surfaces. Therefore, when a difference in thermal elongation in the axial direction occurs between the inner single tube 10 and the outer single tube 11, the inner single tube 1
0 and mesh member 20, outer single tube 11 and mesh member 2
In this case, sliding occurs between the values of 0 and the difference in thermal elongation can be absorbed. Therefore, even if one of the inner peripheral surface side and the outer peripheral surface side of the mesh member 20 causes sliding failure due to foreign matter biting in, the difference in thermal elongation can be absorbed by the other sliding member without hindrance. Therefore, the durability of the exhaust manifold M can be improved. Moreover, when both the inner peripheral surface and the outer peripheral surface of the mesh member 20 can slide normally, the difference in the thermal expansion between the inner single tube 10 and the outer single tube 11 in the axial direction is absorbed. Since the inner and outer peripheral surfaces are shared, the sliding amount of each sliding part is 1 unit.
It is halved as compared with the conventional case having only a portion, and the durability of the mesh member 20 can be improved. Unnecessary movement of the mesh member 20 is restricted by the end surface of the annular concave portion 21 of the outer single tube 11.

Since the downstream ends of the inner and outer collecting pipes 15 and 16 have relatively large diameters, the difference in their thermal elongation in the circumferential direction cannot be ignored, but the difference is caused by the compressive deformation of the mesh member 20. Absorbed.

Further, the mesh member 20 is formed of the inner single pipe 10.
, That is, the free end, that is, the downstream end, can be suppressed from generating noise due to the vibration.

As described above, the heat retaining type exhaust manifold M
The sliding to absorb the difference in the thermal expansion in the axial direction of the inner and outer double walls
The moving part is a single exhaust pipe 5₁~ 5_FourDownstream end and each exhaust assembly
Tube 6 ₁, 6_TwoAnd the downstream end of the
The sliding stroke at each sliding part should be set small.
Is possible, and the sliding parts tilt each other during sliding.
And it becomes difficult to generate heat distortion in each part of the exhaust manifold M.
Can be effectively prevented and its durability can be improved.
You.

The insulation type exhaust manifold M in accordance with a third embodiment of the present invention shown in FIG. 7 is obtained by connecting a single common exhaust collecting pipe 6 to the four exhaust monotube 5 ₁ to 5 _4, the The heat retaining structure and the thermal elongation absorbing structure are substantially the same as those of the first embodiment. In the drawing, the same reference numerals are given to the parts corresponding to those of the first embodiment, and the description is omitted. .

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof. For example, the number and shape of the single exhaust pipe and the exhaust collecting pipe can be freely selected according to the number and type of cylinders of the engine. Further, the heat insulating spaces 12 and 17 can be filled with a heat insulating material.

[0036]

As described above, according to the first aspect of the present invention, one end of the inner tube and the outer tube which are arranged inside and outside are fixed to each other, and the other end is connected between the other ends. In the heat retaining exhaust pipe of an engine, which is provided with an annular mesh member capable of sliding, the outer peripheral surface of the inner pipe is slid into an annular recess formed in the inner peripheral face of the other end of the outer pipe. Since the mesh member to be supported is slidably mounted, both the inner and outer peripheral surfaces of the annular mesh member serve as sliding surfaces, and the sliding between the inner tube and the mesh member and the outer tube and the mesh member. Movement can absorb the difference in thermal elongation in the inner tube and the outer tube in the axial direction. Therefore, even if sliding failure occurs due to foreign matter getting stuck in one of the sliding parts,
The difference in thermal elongation can be absorbed without any trouble by the operation of the other sliding portion, and the durability of the exhaust pipe can be improved. In addition, when both sliding parts operate normally, the difference in thermal expansion between the inner pipe and the outer pipe in the axial direction is shared by the two sliding parts. Compared to the conventional case in which there is only one moving part, the half is halved, and the durability of the mesh member can be improved.

According to a second feature of the present invention, an upper flange, a plurality of exhaust pipes connecting each upstream end to the upper flange, and a downstream end of these exhaust pipes are connected. An exhaust manifold having a lower flange connected to a downstream end of the exhaust manifold, and having a double-walled pipe section. An inner collecting pipe and an outer collecting pipe arranged in an inner and outer doubly, the upstream ends of the inner and outer collecting pipes are fixed to each other, and are fixed to the exhaust pipe.
An annular mesh member that slidably supports the outer peripheral surface of the inner collecting pipe is slidably mounted in an annular recess formed in the inner peripheral surface of the downstream end portion of the outer collecting pipe, and is slidable downstream of the outer collecting pipe. Since the lower flange is connected to the side end, the difference in thermal expansion between the outer collecting pipe and the outer collecting pipe in the axial direction is absorbed by sliding between the outer collecting pipe and the mesh member, and between the outer collecting pipe and the mesh member. can do. Therefore,
Even if sliding failure occurs due to foreign matter being caught in one of the sliding parts, the difference in thermal expansion in the axial direction can be absorbed without any trouble by the operation of the other sliding part. Can be improved. In addition, when both sliding parts operate normally, the difference in thermal expansion between the inner collecting pipe and the outer collecting pipe in the axial direction is shared by the two sliding parts. It is small and can contribute to improving the durability of the mesh member.

[Brief description of the drawings]

FIG. 1 is a side view of an engine equipped with a warmed exhaust manifold according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the exhaust manifold.

FIG. 3 is a partial vertical front view of the exhaust manifold.

FIG. 4 is an enlarged view of a part of FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 1;

FIG. 6 is a sectional view taken along line 6-6 in FIG. 5;

FIG. 7 is a vertical sectional front view of an exhaust manifold showing a second embodiment of the present invention.

[Explanation of symbols]

E · · · · · engine M · · · · · exhaust manifold ₂₁ to ₂₄ ... exhaust port 5 ₁ to 5 ₄ ... exhaust monotube 6 _1, 6 _2, 6 ... exhaust collecting pipe 15 ····· Inside pipe (inside collecting pipe) 16 ··· Outer pipe (outside collecting pipe) 17 ··· Insulated space 20 ··· Mesh member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Taku Komatsuda 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Inventor Tatsumi Yamada 1-4-1 Chuo, Wako-shi, Saitama Inside the Honda R & D Co., Ltd. (72) Inventor Seiji Kato 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside the Honda R & D Co., Ltd. (72) Koichi Fujimori 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside Honda R & D Co., Ltd. (72) Inventor Kazuhiro Furuhashi 508-1 Toyocho, Hamamatsu City, Shizuoka Prefecture Inside Yutaka Giken Co., Ltd.

Claims (2)

[Claims] 1. An annular mesh for fixing one end of an inner tube (15) and an outer tube (16) arranged inside and outside to each other and enabling relative sliding between the other ends. In a heat-insulating exhaust pipe of an engine having a member (20) interposed, an annular concave portion (21) formed in the inner peripheral surface of the other end of the outer pipe (16) has an outer peripheral surface of the inner pipe (15). A warm exhaust pipe for an engine, characterized in that a mesh member (20) slidably mounted on the exhaust pipe is slidably mounted. 2. An upper flange (7) and a plurality of exhaust pipes (5) connecting each upstream end to the upper flange (7).
And _{1-5 4),} the downstream exhaust collecting pipe which is coupled to an end portion (6 _1, 6 _2, 6), the exhaust collecting pipe (6 ₁ of the exhaust monotube (5 ₁ to 5 _4), 6 ₂ , 6) a heat-insulating exhaust manifold having a lower flange (8) connected to the downstream end, and each pipe section having a double wall.
The exhaust manifold (6 ₁ , 6 ₂ , 6) is composed of an inner manifold (15) and an outer manifold (16) arranged in an inner and outer doubly. the exhaust monotube with securing the upstream end to the other (5 ₁ to 5
₄ ) an annular mesh slidably supporting the outer peripheral surface of the inner collecting pipe (15) in an annular recess (21) formed in the inner peripheral surface of the downstream end of the outer collecting pipe (16); The member (20) is slidably mounted on the outer collecting pipe (1).
6. A warm exhaust manifold for an engine, wherein the lower flange (8) is connected to a downstream end of (6).