JP3433096B2 - Heated exhaust manifold for engine - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an upper flange,
A plurality of exhaust single pipes connecting the upstream end portions to the upper flange, an exhaust collecting pipe connected to the downstream end portions of the exhaust single pipes, and a downstream end portion of the exhaust collecting pipes The present invention relates to an improvement of a heat insulation type exhaust manifold of an engine, which is provided with a lower flange and each pipe part is configured with a double wall.

[0002]

2. Description of the Related Art Conventionally, as such a heat retaining type exhaust manifold, as disclosed in, for example, Japanese Patent Application Laid-Open No. 9-280046, an upper flange and a plurality of upstream end portions are connected to the upper flange. An exhaust single pipe, an exhaust collecting pipe that is connected to the downstream end portions of these exhaust single pipes and communicates with them, covers the plurality of exhaust single pipes and the exhaust collecting pipe, and has an upstream end portion as an upstream flange. It consists of a common outer pipe to be joined and a lower flange joined to the downstream end of this outer pipe. The downstream end of the exhaust collecting pipe is slidably supported on the inner peripheral surface of the outer pipe, It is known that the difference in the axial thermal expansion between the end pipe and the exhaust collecting pipe and the outer pipe is absorbed by the sliding between the exhaust collecting pipe and the outer pipe so that thermal distortion does not occur in each part as much as possible. There is.

[0003]

However, in the above-mentioned one, since the plurality of exhaust single pipes and the exhaust collecting pipe are integrally connected, the thermal expansion of each exhaust single pipe is all caused by the exhaust collecting pipe and the outer pipe. It will be concentrated on the sliding part with and the large sliding stroke must be secured at that sliding part.
If the sliding stroke becomes large, the sliding parts may tilt with each other during the sliding process, and thermal distortion may easily occur.

The present invention has been made in view of such circumstances, and an engine which can effectively absorb the difference in axial thermal expansion between the inner and outer double walls with a relatively small sliding stroke. It is an object of the present invention to provide a heat retention type exhaust manifold.

[0005]

In order to achieve the above object, the present invention provides an upper flange, a plurality of exhaust single pipes connecting each upstream end to the upper flange, and downstream of these exhaust single pipes. An exhaust collecting pipe connected to a side end, and a lower flange connected to a downstream end of the exhaust collecting pipe,
In a heat-retaining exhaust manifold of an engine in which each pipe part is composed of a double wall, each exhaust single pipe is composed of an inner single pipe and an outer single pipe arranged in an inner and outer double, and The upstream end portions are fixed to each other and also fixed to the upper flange, the downstream end portion of the inner single pipe is slidably supported on the inner peripheral surface of the outer single pipe, and the exhaust collecting pipe is An inner collecting pipe communicating with the plurality of inner single pipes;
It is composed of an outer collecting pipe covering the inner collecting pipe ,
An upstream end of the side collecting pipe and an upstream end of the outer collecting pipe
The downstream end of the outer single pipe and the three ends are
It is fixed integrally, and the downstream end of the inner collecting pipe is slidably supported on the inner peripheral surface of the outer collecting pipe, and the lower flange is connected to the downstream end of the outer collecting pipe. This is the first feature.

According to the first feature, the difference in thermal expansion between the inner single pipe and the outer single pipe is absorbed by the sliding of the inner and outer single pipes, and the thermal expansion of the inner collecting pipe and the outer collecting pipe is absorbed. The difference can be absorbed by sliding the inner and outer collecting pipes against each other. As described above, in the heat insulation type exhaust manifold, the sliding portions that absorb the difference in the thermal expansion in the axial direction of the inner and outer double walls are provided at the downstream end portions of the inner and outer single pipes and the downstream end portions of the inner and outer collecting pipes. It is possible to set the sliding stroke at each sliding part to be small by providing it separately, and it becomes difficult for the sliding parts to incline relative to each other during sliding, causing thermal strain in each part of the exhaust manifold. This can be effectively prevented, and its durability can be improved. Also especially upstream of the inner collecting pipe
Side end, upstream end of outer collecting pipe, and downstream of outer single pipe
The side edge means that the three are fixed together at the same location.
Be done.

According to the present invention, in addition to the above-mentioned characteristics, each inner single tube is formed with a protrusion slidably supported on the inner peripheral surface of each outer single tube due to its diameter expansion. This is the second feature.

According to this second feature, the downstream end of the inner single pipe is connected to the outer single pipe without using a special sliding member and while ensuring a heat insulating space between the exhaust single pipes. It can be slidably supported on the inner peripheral surface.

Further, in addition to the first or second feature, the present invention is that the downstream end of the inner collecting pipe is slidably supported on the inner peripheral surface of the outer collecting pipe through a mesh member. It is characterized by 3.

According to the third feature, the difference in thermal expansion between the two exhaust collecting pipes is absorbed by the sliding of the two exhaust collecting pipes via the mesh member, and the relatively large amount of the two exhaust collecting pipes is absorbed. The difference in the thermal expansion in the circumferential direction at the downstream end of the diameter can be absorbed by the compressive deformation of the mesh member.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.

FIG. 1 is a side view of an engine equipped with a heat insulation type exhaust manifold according to the first embodiment of the present invention, and FIG.
A perspective view of the exhaust manifold, FIG. 3 is a partially longitudinal front view of the exhaust manifold, and FIG. 4 is an enlarged view of part 4 of FIG.
5 is a sectional view taken along the line 5-5 of FIG. 1 and a sectional view taken along the line 6-6 of FIG. 7 is a sectional view showing a second embodiment of the present invention, and FIG. 8 is a vertical sectional front view of an exhaust manifold showing a third 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 the four-cylinder engine E is
On the front of the Dahead 1 are four exhaust ports corresponding to the cylinders.
2₁~ 2_FourAre open, and these exhaust ports 2₁
~ 2 _FourInsulation of the present invention that guides exhaust gas discharged from
Type exhaust manifold M includes a plurality of stud bolts 3 and
It is attached to the cylinder head 1 by the cover 4.

As shown in FIGS. 2 to 4, the exhaust manifold M includes four exhaust single pipes 5 _{1 to} 5 ₄ which individually communicate with the four exhaust ports 2 ₁ to 2 _4. ，
These are referred to as the first to fourth exhaust single pipes from the left side in FIG.

An upper flange 7 is connected to the upstream end of each of the _first to fourth exhaust single pipes 5 _{1 to} 5 ₄ , and the _first flange is connected to the downstream end of each of the second and third exhaust single pipes 5 ₂ and 5 ₃ . The exhaust collecting pipe 6 ₁ is connected, and the second exhaust pipe is connected to the downstream end of the first and fourth exhaust single pipes 5 ₁ 5 ₄ .
The exhaust collecting pipe 6 ₂ is connected. The lower flange 8 is connected to the downstream end portions of the first and second exhaust collecting pipes 6 ₁ and 6 ₂ . The upper flange 7 is fixed to the cylinder head 1 by the stud bolt 3 and the nut 4, and the lower flange 8 is connected to a not-shown common catalytic converter (exhaust gas purification device) arranged under the floor of the vehicle. The intermediate exhaust pipe 21 is connected. The catalytic converter may be directly connected to the lower flange 8.

Each of the exhaust single pipes 5 _{1 to} 5 ₄ is composed of an inner single pipe 10 and an outer single pipe 11 which are arranged inside and outside, and a cylindrical heat insulating space between the inner and outer single pipes 10 and 11. 12 is 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 single tube 11 is connected to the inner single tube 1.
The diameter is reduced to fit the outer peripheral surface of the upstream end of
Of the upper flange 7 at the upstream end
To 2 ₁~ 2_FourThrough hole 13₁~ 13_FourMated to
With the through hole 13₁~ 13_FourBy welding on the inner 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 transverse cross section, which is bulged to the outer peripheral surface due to the diameter expansion from the inner peripheral side thereof.
It is slidably fitted to the inner peripheral surface of 1. Thus, the downstream end of the inner single tube 10 is slidably supported by the outer single tube 11.

Each of the exhaust collecting pipes 6 ₁ and 6 ₂ is composed of an inner collecting pipe 15 and an outer collecting pipe 16 which are arranged inside and outside so that a heat insulating space 17 is provided between the inner and outer collecting pipes 15 and 16. It is formed. The inner collecting pipe 15 is constructed by stacking a pair of inner collecting pipe halves 15a and 15b made of thin stainless steel plates, which are opposed to each other, and welding the entire overlapped portion. At that time, at the upstream end of the inner collecting pipe 15,
Inner bifurcated tubes 18 and 18 are formed, and the downstream end portions of the corresponding two outer single tubes 11 and 11 are fitted therein.

The outer collecting pipe 16 is also constructed by stacking opposite ends of a pair of outer steel collecting pipe halves 16a and 16b made of stainless steel plates on each other and welding the entire overlapping part. Is thicker than the inner collecting pipe 15. At the upstream end of the outer collecting pipe 16, outer bifurcated pipes 19 and 19 are formed to cover the inner bifurcated pipes 18 and 18, respectively. The tips of the outer bifurcated tubes 19 and 19 are the inner bifurcated tubes 18 and 18
The outer diameters of the outer single pipes 11 and 11 are reduced by welding so that their fitting portions are welded to the outer circumferential surfaces of the downstream end portions of the corresponding two outer single pipes 11, 11.

As shown in FIGS. 5 and 6, the outer collecting pipe 1
The lower flange 8 is fixed to the downstream end of 6 by welding. On the inner peripheral surface of the downstream end of the outer collecting pipe 16, an annular bisected mesh member 20 formed by knitting a stainless wire is attached by welding, and the inner collecting pipe 15 is attached to the inner peripheral surface of the mesh member 20. The downstream end of the is slidably fitted. Thus, the downstream end of the inner collecting pipe 15 is slidably supported by the outer collecting pipe 16 via the mesh member 20.

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

During operation of the engine E, exhaust gas from the four exhaust ports 2 ₁ , 2 ₂ , 2 ₄ , 2 ₃ to the first exhaust single pipe 5 ₁ ,
2nd single exhaust pipe 5 ₂ , 4th single exhaust pipe 5 ₄ , 3rd single exhaust pipe 5
_It is sequentially discharged to ₃ . The exhaust gas passing through the first and fourth exhaust single pipes 5 ₁ and 5 ₄ joins at the first exhaust collecting pipe 6 ₁ , and the exhaust gas passing through the second and third exhaust single pipes 5 ₂ and 5 ₃ is the second exhaust gas. merge at an exhaust merging pipe 6 _2, then the exhaust gas is guided to a common catalytic converter (not shown) while being further joined at the intermediate exhaust pipe 21, it is purified.

By the way, each of the exhaust single pipes 5 _{1 to} 5 ₄ is composed of an inner single pipe 10 and an outer single pipe 11 arranged inside and outside,
The inner single tube 10 is formed thin and a heat insulating space 12 is formed between the inner and outer single tubes 10, 11.
Each of the exhaust collecting pipes 6 ₁ and 6 ₂ is also composed of an inner collecting pipe 15 and an outer collecting pipe 16 arranged in an inner and outer double arrangement, and the inner collecting pipe 15 is formed thin and has inner and outer collecting pipes 15 and 16 respectively. Since 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, it is possible to guide the subsequent exhaust gas to the catalytic converter while suppressing its temperature decrease, promote its activation, and enhance the exhaust gas purification efficiency.

In the meantime, in each of the exhaust single pipes 5 _{1 to} 5 ₄ , the inner single pipe 10 undergoes a larger thermal expansion in the axial direction than the outer single pipe 11 side. The annular projection 14 on the outer peripheral surface of the side end portion slides against the inner peripheral surface of the outer single tube 11 that supports the inner and outer single tubes 1.
The difference in the thermal elongation of 0 and 11 in the axial direction is absorbed.

Also in each of the exhaust collecting pipes 6 ₁ and 6 ₂ ,
Thermal expansion in the axial direction is generated in the inner collecting pipe 15 larger than that in the outer collecting pipe 16 side. With the expansion, the downstream end of the inner collecting pipe 15 is compared with the mesh member 20 supported by the outer collecting pipe 16. Sliding on the inner and outer collecting pipes 15 and 16
The difference in the thermal expansion in the axial direction is absorbed. Further, since the downstream end portions of the inner and outer collecting pipes 15 and 16 have a relatively large diameter, the difference in thermal expansion in the circumferential direction between them cannot be ignored, but the difference is absorbed by the compressive deformation of the mesh member 20. It

In this way, the heat retention type exhaust manifold M is
In order to absorb the difference in axial thermal expansion between the inner and outer double walls,
Moving part of each exhaust single pipe 5₁~ 5_FourDownstream end and each exhaust assembly
Tube 6 ₁, 6₂By providing it separately from the downstream end of
Set the sliding stroke at each sliding part to a small value.
It becomes possible that the sliding parts tilt during sliding.
It becomes difficult and heat distortion occurs in each part of the exhaust manifold M.
Can be effectively prevented and its durability can be improved.
It

In the second embodiment of the present invention shown in FIG. 7, an annular projection 14 is formed on the outer peripheral surface of the downstream end of each inner single tube 10.
Is a trapezoidal cross section. Since other configurations are the same as those of the previous embodiment, the same reference numerals are given to the portions corresponding to those of the previous embodiment in the drawing, and the description thereof will be omitted.

A heat retaining type exhaust manifold M according to a third embodiment of the present invention shown in FIG. 8 is one in which one exhaust collecting pipe 6 is commonly connected to _four exhaust single pipes 5 _{1 to} 5 _4. The heat retaining structure and the heat expansion absorbing structure are substantially the same as those of the first embodiment. In the figure, the same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. .

Although the embodiments of the present invention have been described in detail above, the present invention can be modified in various ways without departing from the scope of the invention. For example, the number and shape of the exhaust single 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. Further, on the outer periphery of the downstream side end portion of the inner single tube 10, a plurality of protrusions in an annular arrangement may be formed instead of the annular protrusion 14.

[0032]

As described above, according to the first feature of the present invention, in the heat insulation type exhaust manifold of the engine, each of the exhaust single pipes is composed of an inner single pipe and an outer single pipe which are arranged inside and outside dually. Then, the upstream end portions of the inner and outer single pipes are fixed to each other and also fixed to the upper flange, and the downstream end portion of the inner single pipe is slidably supported on the inner peripheral surface of the outer single pipe. The exhaust collecting pipe is composed of an inner collecting pipe communicating with the plurality of inner single pipes, and an outer collecting pipe covering the inner collecting pipe, and an upstream end portion of the inner collecting pipe.
The upstream end of the outer collecting pipe and the downstream end of the outer single pipe
And the downstream end of the inner collecting pipe are slidably supported on the inner peripheral surface of the outer collecting pipe, and the lower flange is attached to the downstream end of the outer collecting pipe. Since they are connected, the difference in the axial thermal expansion of the inner and outer double walls of each pipe part should be absorbed by the sliding part between the downstream end of each exhaust single pipe and the downstream end of the exhaust collecting pipe. As a result, it is possible to set the sliding stroke at each sliding part to a small value, making it difficult for the sliding parts to incline relative to each other during sliding, and effectively preventing thermal distortion in each part of the exhaust manifold. ， The durability can be improved. Also especially the inner set
The upstream end of the pipe and the upstream end of the outer collecting pipe
The downstream end of the pipe means that the three are integral with each other at the same location.
Stuck to.

According to the second feature of the present invention, since the inner single tube is formed with a protrusion that is slidably supported on the inner peripheral surface of the outer single tube due to its diameter expansion, a special sliding is provided. The downstream end of the inner single pipe can be slidably supported on the inner peripheral surface of the outer single pipe without using a moving member and while securing a heat insulating space between the inner and outer single pipes. This can contribute to simplification of the structure.

Further, according to the third feature of the present invention, the third feature is that the downstream end of the inner collecting pipe is slidably supported on the inner peripheral surface of the outer collecting pipe through a mesh member.

According to the third feature, the difference in thermal expansion between the two exhaust collecting pipes is absorbed by the mutual sliding of the two exhaust collecting pipes via the mesh member, and the relatively large amount of the two exhaust collecting pipes is absorbed. The difference in the thermal expansion in the radial direction at the downstream end of the diameter can be absorbed by the compressive deformation of the mesh member.

[Brief description of drawings]

FIG. 1 is a side view of an engine including a heat retention type 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 part 4 of FIG.

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

6 is a sectional view taken along line 6-6 of FIG.

FIG. 7 is a sectional view showing a second embodiment of the present invention.

FIG. 8 is a vertical cross-sectional front view of an exhaust manifold showing a third embodiment of the present invention.

[Explanation of symbols]

E ... Engine M ... Exhaust manifold 2 ₁ to 2 ₄ ... Exhaust port 5 _{1 to} 5 ₄ ... Exhaust single pipe 6 ₁ , 6 ₂ , 6 ... Exhaust collecting pipe 10・ ・ ・ ・ Inner single tube 11 ・ ・ ・ Outer single tube 12 ・ ・ ・ ・ ・ ・ Insulating space 14 ・ ・ ・ ・ Projection 15 ・ ・ ・ ・ Inner collecting pipe 16 ・ ・ ・ ・ ・ ・ Outer collecting pipe 17 ・ ・ ・Space 20 ... Mesh member

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Ishii 1-4-1 Chuo, Wako-shi, Saitama, Ltd. Inside the Honda R & D Co., Ltd. (72) Inventor Takashi Komatsuda 1-4-1 Chuo, Wako, Saitama Company Honda R & D Co., Ltd. (72) Inventor Hiroshi Hashimoto 1-4-1 Chuo, Wako-shi, Saitama Stock Company Honda R & D Co. (72) Inventor Tatsumi Yamada 1-1-4 Chuo, Wako-shi, Saitama Stock Company Honda Technical Research Institute (72) Inventor Kazuhiro Furuhashi 1 508 Toyomachi, Hamamatsu City, Shizuoka Yutaka Giken Co., Ltd. , A) Actual development Sho 57-54613 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F01N 7/10 F01N 7/08 F01N 7/14

Claims (3)

(57) [Claims] 1. An upper flange (7) and a plurality of single exhaust pipes (5) connecting each upstream end to the upper flange (7).
_{1 to} 5 ₄ ), the exhaust collecting pipes (6 ₁ , 6 ₂ , 6) coupled to the downstream side end portions of these exhaust single pipes (5 _{1 to} 5 ₄ ), and the exhaust collecting pipes (6 ₁ , 6 _2, 6) and a lower flange (8) which is coupled to the downstream end of each tube portion is constituted by a double wall, in heat insulation type exhaust manifold of the engine, each exhaust monotube (5 ₁ - 5 ₄ ) is composed of an inner single pipe (10) and an outer single pipe (11) arranged in an inner and outer double, and the upstream ends of these inner and outer single pipes (10, 11) are fixed to each other. Fixed to the upper flange (7),
The downstream end of the inner single pipe (10) is connected to the outer single pipe (1
1) is slidably supported on the inner peripheral surface, and the exhaust collecting pipes (6 ₁ , 6 ₂ , 6) are connected to the inner single pipes (10).
An inner collecting pipe (15) communicating with the inner collecting pipe (1)
5) constitute from outside the collector pipe (16) for covering said inner
The upstream end of the collecting pipe (15) and the outer collecting pipe (16)
Of the upstream end of the outer single tube (11) and the downstream end of the outer single pipe (11)
The three members are integrally fixed to each other at the same location, and the downstream end of the inner collecting pipe (14) is slidably supported on the inner peripheral surface of the outer collecting pipe (15), and the outer collecting pipe is (15)
A heat retaining exhaust manifold for an engine, characterized in that the lower flange (8) is connected to the downstream end of the engine. 2. The projection according to claim 1, wherein each inner single tube (10) is slidably supported on the inner peripheral surface of each outer single tube (11) due to its expanded diameter. A heat retaining exhaust manifold for an engine, characterized in that (14) is formed. 3. The one according to claim 1 or 2, wherein the downstream end of the inner collecting pipe (15) is slidable on the inner peripheral surface of the outer collecting pipe (16) through a mesh member (20). A heat retaining exhaust manifold for engines, which is characterized by being supported by