JP3452528B2 - Exhaust manifold - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a four-cylinder, a six-cylinder,
The present invention relates to an exhaust manifold that collects exhaust gas exhausted from each exhaust port of a multi-cylinder engine such as an 8-cylinder and sends it to an exhaust pipe.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 10-89061, three metal members, a front half body, a partition body, and a back half body, are overlapped with each other to form a space between the front half body and the partition body. A second exhaust pipe and a third exhaust pipe communicating with the exhaust ports of the second cylinder and the third cylinder, respectively, and the exhaust of the first cylinder and the fourth cylinder between the partition body and the back half. No. 1 exhaust pipe and No. 4 communicating with the port
An exhaust manifold that forms an exhaust pipe has been proposed.

In this exhaust manifold, a muffler chamber cover for forming a muffler chamber is further attached to a downward curved portion, and the muffler chamber and each exhaust pipe are connected to each other through a communication hole to form an exhaust sound.・ I tried to reduce the radiated sound.

[0004]

However, in such a conventional one, the silencer chamber cover is welded to the curved portions of the partition body and the back half body along the outer periphery of the silencer chamber cover so as to maintain airtightness. Since it is attached, the assembly work becomes complicated. In addition, the volume increases due to the provision of a muffling room,
In some cases, the temperature of the exhaust gas decreases, which hinders the function of the catalyst provided downstream.

An object of the present invention is to provide an exhaust manifold having a simple structure and a sound deadening effect without deteriorating the temperature characteristics.

[0006]

In order to achieve the above object, the present invention takes the following means in order to solve the object. That is, an exhaust manifold is connected to a collecting pipe part that is a collection of branch pipe parts connected to each exhaust port of a multi-cylinder engine, and the exhaust manifold exhaust gas exhausted from each exhaust port is sent to the exhaust pipe. An outer case having a pipe part and the collecting pipe part is formed, and a cross-sectional area of the collecting pipe part is formed larger than a cross-sectional area of the exhaust port, and one end of a partition pipe provided in the outer case. To the exhaust port, the other end of the partition pipe is extended from inside the branch pipe portion to reach the inside of the collecting pipe portion, and
A large number of small holes are formed in the partition tube so that the partition tube and the
While communicating with the inside of the joint pipe, the opening of the partition pipe
It is an exhaust manifold characterized by being placed in the middle of the joint .

Further, an exhaust pipe is connected to a collecting pipe part which is a collection of branch pipe parts connected to the first to fourth exhaust ports of a four-cylinder engine, and exhaust gas exhausted from the first to fourth exhaust ports. In the exhaust manifold that sends the exhaust gas to the exhaust pipe, the exhaust sequence from the first to fourth exhaust ports is first, third,
A fourth and a second outer case are provided, in which the branch pipe portion and the collecting pipe portion are formed, and the cross sectional area of the collecting pipe portion is formed larger than the cross sectional area of the exhaust port. One end of a partition pipe provided inside communicates with the second and third exhaust ports, respectively, and the other end side of the partition pipe is gathered to extend from inside the branch pipe portion to reach the inside of the collecting pipe portion, A large number of small holes are formed in the partition pipe in the collecting pipe.
When formed, the partition pipe and the inside of the collecting pipe are communicated with each other.
In addition, the opening of the partition pipe may be arranged in the middle of the collecting pipe .

The branch pipe portion may be in communication with the first exhaust port, the second and third exhaust ports, and the fourth exhaust port, respectively. Further, the cross-sectional area of the partition tube is substantially equal to the cross-sectional area of the exhaust port, have a structure in which a reinforcing member between the partition tube and the outer casing
Good.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. As shown in FIGS. 1 and 2, 1
Is an exhaust manifold, which is used in the four-cylinder engine 100 in this embodiment. Engine 10
No. 0 has first to fourth exhaust ports P1 to P4 communicating with the first to fourth cylinders # 1 to # 4. In the present embodiment, the first cylinder # 1, the third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 3.
Ignition is performed in the order of cylinder # 2.

The exhaust manifold 1 has a large flange 2, an outer case 4, a partition pipe 6 provided in the outer case 4, and a small flange 8. As shown in FIG. 4, the large flange 2 has first to fourth exhaust ports P1 to P1.
Four through holes 10 to 13 corresponding to P4 are bored, and a plurality of mounting holes 14 to 18 for mounting the large flange 2 to the engine 100 with bolts (not shown).
Are formed. As shown in FIG. 6, annular projections 20 to 23 projecting toward the outer case 4 are formed around the four through holes 10 to 13.

The outer case 4 includes the first to third branch pipe portions 2
4 to 26, and a collecting pipe portion 28 connected to the first to third branch pipe portions 24 to 26. In the present embodiment, the outer case 4 is formed from a plate-shaped material into a hollow cylindrical shape by a molding process using a press. An opening 29 is formed at an end of the collecting pipe portion 28, a small flange 8 is attached to the exhaust manifold 1 on the opening 29 side, and the small flange 8 is flange-connected to an exhaust pipe (not shown). The outer case 4 has a relatively large wall thickness, which is 1.
It is formed to be 5 mm.

On the other hand, the first to third branch pipe portions 24 to 26 are
As shown in FIGS. 2 and 4, both sides of the outer case 4 are separated by the recessed portions 30 and 32 which are recessed and overlapped. The first branch pipe portion 24 and the third branch pipe portion 26 are formed in a substantially circular shape, and the second branch pipe portion 25 includes the second and third branch pipe portions 25.
It is formed in an oval shape so as to straddle the exhaust ports P2, P3. In the present embodiment, a recess 33 is formed in the second branch pipe portion 25 so that the bolt can be inserted into the mounting hole 16.

As shown in FIG. 2, the first branch pipe portion 24 has a first
The first branch pipe portion 24 and the first exhaust port P1 are communicated with each other by being fitted into the annular projection 20 of the through hole 10 that communicates with the exhaust port P1. The third branch pipe portion 26 is fitted into the annular projection 23 of the through hole 13 that communicates with the fourth exhaust port P4, and the third branch pipe portion 26 and the fourth exhaust port P4 communicate with each other.

The partition tube 6 is also formed in a hollow shape by press forming, and has a wall thickness of 0.8 mm in this embodiment.
And is thinly formed. The partition pipe 6 is provided with first and second branch pipe parts 34 and 36, and a merging pipe part 38 connected to the first and second branch pipe parts 34 and 36.

The first and second branch pipe portions 34 and 36 are shown in FIG.
As shown in FIG. 4, both sides of the partition pipe 6 are separated by a recessed portion 39 which is recessed and overlapped with each other, and both branch pipe portions 34 and 36 are formed in a substantially circular shape. Then, the first and second branch pipe portions 34, 36 are merged at the merge pipe portion 38, and the other end side of the merge pipe portion 38 is extended to reach the collecting pipe portion 28, and is inside the collecting pipe portion 28. The opening 37 is formed (see FIG. 3).

The first branch pipe portion 34 is fitted into the annular projection 21 of the through hole 11 communicating with the second exhaust port P2,
The second branch pipe portion 36 is fitted into the annular projection 22 of the through hole 12 that communicates with the third exhaust port P3. The cross-sectional areas of the first branch pipe portion 34 and the second branch pipe portion 36 are formed to be substantially the same as the cross-sectional areas of the second exhaust port P2 and the third exhaust port P3. Further, the cross-sectional area of the merging pipe portion 38 is formed to be substantially the same as the cross-sectional area of both the second and third exhaust ports P2, P3.

The partition tube 6 is inserted into the outer case 4, and plate-shaped reinforcing members 40 and 42 are provided between the outer case 4 and the partition tube 6. Reinforcement member 4
As shown in FIG. 3, 0 and 42 are provided along the partition pipe 6 from the large flange 2 to the vicinity of the opening 37.

Further, the reinforcing members 40 and 42 are provided at an intermediate position between the second exhaust port P2 and the third exhaust port P3, and divide the inside of the second branch pipe portion 25 and the collecting pipe portion 28 into substantially equal parts. The collecting pipe portion 28 is partitioned into a first chamber 28a and a second chamber 28b (see FIG. 5).

The first branch pipe portion 24 is formed so that its cross-sectional area is substantially the same as the cross-sectional area of the first exhaust port P1.
The sectional area of the branch pipe portion 26 is formed to be substantially the same as the sectional area of the fourth exhaust port P4. The cross-sectional area of the first chamber 28a and the second chamber 28b of the collecting pipe portion 28 is the cross-sectional area obtained by subtracting the cross-sectional area of the partition pipe 6 from the cross-sectional area of the first branch pipe portion 24 and the third branch pipe portion 26. Are also formed to be large.

As shown in FIG. 6, the partition pipe 6 is inserted into the outer case 4, and the second branch pipe portion 25 of the outer case 4 is inserted.
As shown in FIG. 2, the first and second branch pipe portions 34, 36
It is attached to both annular protrusions 21 and 22 from above. Then, welding is performed along the outer circumference of the outer case 4, and the outer case 4 and the partition pipe 6 are integrally attached to the large flange 2.

The first exhaust port P1 has a through hole 10 and a first
The exhaust gas is sent from the opening 29 to the exhaust pipe by being communicated with the opening 29 through the branch pipe portion 24 and the first chamber 28a of the collecting pipe portion 28. The second exhaust port P2 communicates with the opening 29 through the through hole 11, the first branch pipe portion 34, the confluent pipe portion 38, the opening 37, and the collecting pipe portion 28, and the exhaust gas is sent from the opening 29 to the exhaust pipe. .

The third exhaust port P3 has a through hole 12 and a second
Branch pipe part 36, merging pipe part 38, opening 37, collecting pipe part 28
The exhaust gas is sent from the opening 29 to the exhaust pipe. The fourth exhaust port P4 has a through hole 1
3, the third branch pipe portion 26, and the second chamber 28b of the collecting pipe portion 28 communicate with the opening 29, and the exhaust gas is sent from the opening 29 to the exhaust pipe.

Further, the opening 37 of the partition pipe 6 is arranged in the middle of the collecting pipe portion 28 of the outer case 4, and the collecting pipe portion 2
A large number of small holes 44 are provided in the merging pipe part 38 in the merging pipe part 3
8 is drilled. The merging pipe portion 38 communicates with the first chamber 28a and the second chamber 28b via the small hole 44.

Next, the operation of the above-described exhaust manifold of this embodiment will be described. Exhaust gas produced by combustion in the first cylinder # 1 flows into the first branch pipe portion 24 from the first exhaust port P1 through the through hole 10. Then, it passes through the first chamber 28a of the collecting pipe portion 28 and is sent to an exhaust pipe (not shown). Next, the exhaust gas generated by the combustion in the third cylinder # 3 flows from the third exhaust port P3 through the through hole 12 into the second branch pipe section 36 of the partition pipe 6. Then, it passes through the partition pipe 6, flows into the collecting pipe portion 28 from the opening 37 and the small hole 44, and is sent from the collecting pipe portion 28 to the exhaust pipe.

Subsequently, the exhaust gas produced by the combustion in the fourth cylinder # 4 flows into the third branch pipe portion 26 from the fourth exhaust port P4 through the through hole 13. And the second of the collecting pipe part 28
It passes through the chamber 28b and is sent to an exhaust pipe (not shown). At that time, combustion continues in the third cylinder # 3 and the fourth cylinder # 4,
In the third exhaust port P3 and the fourth exhaust port P4, the exhaust sequence is continuous, and the exhaust ports P3 and P4 are adjacent to each other. However, due to the partition pipe 6, the third exhaust port P3
Exhaust gas from is prevented from flowing into the fourth exhaust port P4 side, and exhaust interference is prevented.

Next, the exhaust gas produced by the combustion in the second cylinder # 2 flows from the second exhaust port P2 through the through hole 11 into the first branch pipe portion 34 of the partition pipe 6. And the partition tube 6
After passing through the inside, it flows into the collecting pipe portion 28 from the opening 37 and the small hole 44, and is sent from the collecting pipe portion 28 to the exhaust pipe. The above-described operation is repeated, and the exhaust gas flows into the first branch pipe portion 24 due to the combustion in the first cylinder # 1.

At this time, the exhaust sequence of the second exhaust port P2 and the first exhaust port P1 is continuous, and both exhaust ports P2
1 and P2 are adjacent to each other. However, the partition pipe 6 suppresses the exhaust gas from the second exhaust port P2 from flowing into the first exhaust port P1 side, exhaust interference is prevented, and the output torque is not reduced.

On the other hand, when the engine 100 is started, the temperatures of the outer case 4 and the partition pipe 6 are low, and the heat of the exhaust gas is taken by the outer case 4 and the partition pipe 6. However, the heat capacity of the partition tube 6 is small, and the temperature of the partition tube 6 rapidly rises due to the heat of the exhaust gas. Therefore, the temperature of the exhaust gas passing through the exhaust manifold 1 is recovered in a short time, and the catalyst purification efficiency can be improved.

During the operation of the engine 100, the first and the fourth
Exhaust gas from the cylinders # 1 and # 4 is supplied to the first and third branch pipe portions 2
4 and 26 flow into the collecting pipe portion 28, but the collecting pipe portion 28
First and second chambers 2 partitioned by the reinforcing members 40 and 42 of
The cross-sectional areas of 8a and 28b are the first and third branch pipe portions 24 and 26.
Since it is larger than the cross sectional area of the exhaust gas, the exhaust gas expands and is silenced by the expansion effect and the resonance effect. The cross-sectional areas of the first and second chambers 28a and 28b may be set to suitable cross-sectional areas so that the silencing effect can be exhibited by experiments or the like.

Exhaust gas from the second and third cylinders # 2, # 3 passes through the inside of the partition pipe 6, and flows from the opening 37 and the small hole 44 into the first and second chambers 28a, 28b of the collecting pipe portion 28. Although flowing in, the exhaust gas expands because the cross-sectional area of the collecting pipe portion 28 is large. Sound waves accompanying exhaust gas are reflected from the inner wall of the outer case 4 to the inner wall, interfere with each other, and are silenced. As described above, since the exhaust manifold 1 can muffle the sound, the muffler (not shown) can be downsized, and the glass wool in the muffler can be eliminated. Further, the reinforcing members 40 and 42 suppress the vibration and the like of the partition tube 6 and prevent the generation of noise and the like.

In this embodiment, the partition pipes 6 are provided at the second exhaust port P2 and the third exhaust port P3, but instead of this, partition pipes are provided at the first exhaust port P1 and the fourth exhaust port P4. It may be provided in and. That is, the order of exhaust is continuous, and both exhaust ports can be implemented by providing a partition pipe in the adjacent exhaust ports.

Next, an exhaust manifold of a second embodiment different from the above-mentioned embodiment will be described with reference to FIGS. 7 to 9. The same members as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In the second embodiment, a first partition pipe 50 and a second partition pipe 52 are provided inside the outer case 4. The first partition pipe 50, like the partition pipe 6 described above, has first and second branch pipe portions 54, 56.
And a merging pipe portion 58 connected to the first and second branch pipe portions 54 and 56.

The first branch pipe portion 54 communicates with the second exhaust port P2, and the second branch pipe portion 56 communicates with the third exhaust port P3. The other end of the merging pipe portion 58 extends to reach the collecting pipe portion 28, and an opening 60 is arranged in the collecting pipe portion 28. Also in the second partition pipe 52, the first branch pipe portion 62,
64, and a merging pipe portion 66 connected to the first and second branch pipe portions 62, 64. The first branch pipe portion 62 communicates with the first exhaust port P1 and the second branch pipe portion 64 communicates with the fourth exhaust port P4. The other end of the merging pipe portion 66 is extended to reach the collecting pipe portion 28.
An opening 68 is arranged therein.

Each of the merging pipe portions 58 and 66 is formed in a semicircular shape in cross section. As shown in FIG. 9, the merging pipe portions 58 and 66 are joined together in the collecting pipe portion 28 to have a circular cross section. It is configured to In addition, both confluence pipe parts 58,
A large number of small holes 70 and 72 are formed in the 60. The first and second partition pipes 50, 5 are provided at the tips of the two joining pipe portions 58, 66.
A reinforcing member 74 is provided between the outer case 4 and the outer case 4, and the tips of the first and second partition tubes 50 and 52 are fixed to the outer case 4.

Next, the operation of the exhaust manifold of the second embodiment will be described. In this exhaust manifold, the exhaust gas discharged from the first to fourth exhaust ports P1 to P4 is separated into the first and second branch pipe portions 5 which are different from each other.
4, 56, 62, 64, and join pipe sections 58, 66,
Since it flows out to the exhaust pipe through the collecting pipe portion 28, exhaust interference can be prevented more effectively. In addition, the first and second partition tubes 5
By reducing the plate thickness of 0.52, the heat capacity can be reduced, and the temperature of the exhaust gas can be recovered in a short time when the engine is started.

Further, when flowing into the collecting pipe portion 28 from both the joining pipe portions 58, 60, the cross-sectional area becomes large, so that the exhaust gas expands and is silenced by the expansion effect and the resonance effect.
The cross-sectional area of the collecting pipe portion 28 is preferably set to a suitable cross-sectional area so that the silencing effect is exhibited.

The present invention is not limited to such an embodiment as described above, and can be carried out in various modes without departing from the scope of the present invention.

[0038]

As described above in detail, the exhaust manifold of the present invention has a small heat capacity, the temperature of the exhaust gas passing through the exhaust manifold is recovered in a short time, and the catalyst purification efficiency can be improved. Further, since exhaust interference can be prevented, the output torque of the engine is not reduced. Further, since the sound can be silenced by the expansion of the exhaust gas in the collecting pipe portion, the sound deadening efficiency is improved, the muffler can be downsized, and the glass wool can be eliminated. Moreover, the partition tube has a simple structure, is easy to manufacture, and can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a front view of an exhaust manifold according to an embodiment of the present invention.

FIG. 2 is a plan view of the exhaust manifold of the present embodiment.

FIG. 3 is a side view showing a part of the exhaust manifold of the present embodiment in a cutaway manner.

4 is a cross-sectional view taken along the line AA of FIG.

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

FIG. 6 is an exploded view of the exhaust manifold of the present embodiment.

FIG. 7 is a plan view of the exhaust manifold of the second embodiment.

FIG. 8 is a side view showing a partially broken exhaust manifold of the second embodiment.

9 is a sectional view taken along line CC of FIG.

[Explanation of symbols]

1 ... Exhaust manifold 2 ... Large flange 4 ... Outer case 6 ... Partition pipe 8 ... Small flange 10-13 ... Through hole 24 ... First branch pipe part 25 ... Second branch pipe part 26 ... Third branch pipe part 28 ... Assembly Pipe part 28a ... 1st chamber 28b ... 2nd chamber 34, 54, 62 ... 1st branch pipe part 36, 56, 64 ... 2nd branch pipe part 37, 60, 68 ... Opening 38, 58, 66 ... Merge pipe part 40, 42, 74 ... Reinforcing member 44, 70, 72 ... Small hole 50 ... First partition tube 52 ... Second partition tube 100 ... Engine

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F01N 7/10 F01N 7/08

Claims (5)

(57) [Claims] 1. An exhaust manifold in which an exhaust pipe is connected to a collecting pipe part in which branch pipe parts connected to each exhaust port of a multi-cylinder engine are connected and exhaust gas exhausted from each exhaust port is sent to the exhaust pipe. A partition provided in the outer case, which comprises an outer case in which the branch pipe portion and the collecting pipe portion are formed, and which has a cross-sectional area of the collecting pipe portion larger than that of the exhaust port. One end of the pipe is communicated with the exhaust port, the other end of the partition pipe is extended from inside the branch pipe portion to reach the inside of the collecting pipe portion, and
Forming a large number of small holes in the partition tube, the partition tube and the
While communicating with the inside of the collecting pipe, the opening of the partition pipe is
An exhaust manifold characterized by being placed in the middle of the collecting pipe . 2. An exhaust gas exhausted from the first to fourth exhaust ports by connecting an exhaust pipe to a collecting pipe part which is a collection of branch pipe parts connected to the first to fourth exhaust ports of a four-cylinder engine. In the exhaust manifold, the exhaust sequence from the first to fourth exhaust ports is first, third, fourth, and second, and the outer pipe is formed with the branch pipe portion and the collecting pipe portion. A case is provided, and a cross-sectional area of the collecting pipe portion is formed larger than a cross-sectional area of the exhaust port, and one end of a partition pipe provided in the outer case communicates with the second and third exhaust ports, respectively. , Collecting the other end side of the partition pipe and extending from inside the branch pipe portion until reaching the inside of the collecting pipe portion, and
A small hole is formed to connect the partition pipe and the inside of the collecting pipe.
And the opening of the partition pipe is arranged in the middle of the collecting pipe.
Exhaust manifold characterized by having done. 3. One end of another partition pipe provided in the outer case is connected to the first and fourth exhaust ports, respectively, and the other end sides of the partition pipes are assembled so that the inside of the branch pipe is from the inside of the branch pipe. 3. The exhaust manifold according to claim 2, wherein the exhaust manifold extends until it reaches the opening, and is opened in the collecting pipe portion. 4. The exhaust according to claim 2 or 3, wherein the branch pipe portion communicates with the first exhaust port, the second and third exhaust ports, and the fourth exhaust port, respectively. Manifold. 5. The cross-sectional area of the partition pipe is substantially equal to the cross-sectional area of the exhaust port, and a reinforcing member is provided between the partition pipe and the outer case. Exhaust manifold described.