JP2001289044A - Exhaust manifold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust manifold having a simple constitution and a silencing effect without causing deterioration in the temperature characteristics. SOLUTION: The exhaust order from the first to the forth exhaust port of a 4-cylinder engine is the first, the third, the forth, and the second, and an exhaust pipe is connected to a collective pipe part 28 collecting a first to a third branch pipe part 24-26 connected to the first - the forth exhaust port. An outer case 4 formed with the first - the third branch pipe part 24-26 and the collective pipe part 28 is provided and the cross section of the collective pipe part 28 is formed larger than the cross section of the exhaust port. One ends of a partition pipe 6 provided in the outer case 4 are communicated with the second and the third exhaust port respectively, and the other ends side of the partition pipe 6 is collected and extended from the second branch part 25 inside to the collective pipe part 28 inside and opened to the collective pipe part 28 inside. A reinforcing member is provided between the partition pipe 6 and the outer case 4 and a lot of small holes are bored in the partition pipe 6 in the collective pipe 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a four-cylinder, six-cylinder,
The present invention relates to an exhaust manifold that collects exhaust gas exhausted from exhaust ports of a multi-cylinder engine such as an eight-cylinder engine and sends the collected exhaust gas to an exhaust pipe.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. Hei 10-89061, three metal members of a front half, a partition, and a back half are overlapped to form a gap between the front half and the partition. A second exhaust pipe and a third exhaust pipe communicating with the respective exhaust ports of the second cylinder and the third cylinder, and each exhaust of the first cylinder and the fourth cylinder is provided between the partition body and the back half. The first exhaust pipe communicating with the port and the fourth exhaust pipe
An exhaust manifold having an exhaust pipe has been proposed.

The exhaust manifold is further provided with a sound deadening chamber cover for forming a sound deadening chamber in a downwardly curved portion, and formed so as to connect the sound deadening chamber and each exhaust pipe through a communication hole, thereby forming a sound exhaust sound.・ The radiated sound was reduced.

[0004]

However, in such a conventional device, the sound deadening chamber cover is welded to the curved portion of the partition body and the back half along the outer periphery of the sound deadening chamber cover so as to maintain airtightness. The mounting makes the assembling work complicated. In addition, the volume increased due to the provision of the silencer,
There is a case where the temperature of the exhaust gas decreases and the function of the catalyst provided downstream is hindered.

[0005] An object of the present invention is to provide an exhaust manifold having a simple structure and a silencing effect without deteriorating temperature characteristics.

[0006]

In order to achieve the above object, the present invention takes the following means to solve the problem. That is, in the exhaust manifold, an exhaust pipe is connected to a collecting pipe section in which branch pipe sections connected to each exhaust port of a multi-cylinder engine are collected, and exhaust gas exhausted from each exhaust port is sent to the exhaust pipe. An outer case in which a pipe portion and the collecting pipe portion are formed, 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. The exhaust manifold is characterized in that the end of the partition pipe extends from the branch pipe section to the inside of the collecting pipe section and is opened in the collecting pipe section. .

An exhaust pipe is connected to a collecting pipe section in which branch pipe sections connected to first to fourth exhaust ports of a four-cylinder engine are collected, and exhaust gas exhausted from the first to fourth exhaust ports is provided. In the exhaust manifold for sending air to the exhaust pipe, the order of exhaust from the first to fourth exhaust ports is first, third, and third.
Fourth and second, an outer case in which the branch pipe portion and the collecting pipe portion are formed, wherein a cross-sectional area of the collecting pipe portion is formed larger than a cross-sectional area of the exhaust port; One end of a partition pipe provided therein communicates with the second and third exhaust ports, respectively, and the other ends of the partition pipes are gathered and extended from inside the branch pipe part to reach the inside of the collecting pipe part, An exhaust manifold characterized by being opened in the collecting pipe portion is the exhaust manifold. Further, one end of another partition pipe provided in the outer case is communicated with the first and fourth exhaust ports, respectively, and the other ends of the partition pipes are gathered until they reach the inside of the branch pipe from the inside of the branch pipe. It may be configured to extend and open inside the collecting pipe portion.

[0008] The branch pipe portion may be configured to communicate with the first exhaust port, the second and third exhaust ports, and the fourth exhaust port, respectively. The sectional area of the partition tube may be substantially equal to the sectional area of the exhaust port, and a reinforcing member may be provided between the partition tube and the outer case. Further, the partition pipe in the collecting pipe may be formed with a number of small holes.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1 and FIG.
An exhaust manifold is used for the four-cylinder engine 100 in this embodiment. Engine 10
0 includes 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, the second cylinder
It is ignited 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 first to fourth exhaust ports P <b> 1 to P <b> 1 are provided on the large flange 2.
Four through holes 10 to 13 corresponding to P4 are formed, 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 first to third branch pipe portions 2.
4 to 26, and a collecting pipe part 28 connected to the first to third branch pipe parts 24 to 26. In the present embodiment, the outer case 4 is formed into a hollow cylindrical shape from a plate-like material by press forming. 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.
It is formed to be 5 mm.

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

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

The partition tube 6 is also formed hollow by press molding, and in this embodiment, the wall thickness is 0.8 mm.
It is formed thinly. The partition pipe 6 is provided with first and second branch pipe sections 34 and 36 and a junction pipe section 38 connected to the first and second branch pipe sections 34 and 36.

The first and second branch pipe portions 34 and 36 are shown in FIG.
As shown in FIG. 4, the front and back sides of the partition tube 6 are depressed and separated by a concave portion 39 which is superposed, and both branch pipe portions 34 and 36 are formed in a substantially circular shape. Then, the first and second branch pipe portions 34 and 36 are joined at a joining pipe portion 38, and the other end of the joining pipe portion 38 is extended until reaching the collecting pipe portion 28. An opening 37 is formed (see FIG. 3).

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

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

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 substantially equally divide the inside of the second branch pipe section 25 and the collecting pipe section 28 into two. The collecting pipe section 28 is partitioned into a first chamber 28a and a second chamber 28b (see FIG. 5).

The first branch pipe portion 24 has a cross-sectional area substantially equal to the cross-sectional area of the first exhaust port P1.
The cross-sectional area of the branch pipe portion 26 is substantially the same as the cross-sectional area of the fourth exhaust port P4. The sectional area of the first chamber 28a and the second chamber 28b of the collecting pipe part 28 is obtained by subtracting the sectional area of the partition pipe 6 from the sectional area of the first branch pipe part 24 and the third branch pipe part 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 provided.
As shown in FIG. 2, the first and second branch pipe portions 34, 36
Are mounted on the annular projections 21 and 22 from above. Then, welding is performed along the outer periphery 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, a first
The branch pipe portion 24 communicates with the opening 29 via the first chamber 28a of the collecting pipe portion 28, and exhaust gas is sent from the opening 29 to the exhaust pipe. The second exhaust port P2 communicates with the opening 29 via the through hole 11, the first branch pipe part 34, the merging pipe part 38, the opening 37, and the collecting pipe part 28, and exhaust gas is sent from the opening 29 to the exhaust pipe. .

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

The opening 37 of the partition pipe 6 is arranged in the middle of the collecting pipe section 28 of the outer case 4, and
8 has a number of small holes 44 in the merging pipe section 3.
8 are drilled. Through the small hole 44, the merging tube 38 communicates with the first chamber 28a and the second chamber 28b.

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

Subsequently, the exhaust gas from 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
After passing through the chamber 28b, it is sent to an exhaust pipe (not shown). At that time, combustion continues in the third cylinder # 3 and the fourth cylinder # 4,
The exhaust order is continuous between the third exhaust port P3 and the fourth exhaust port P4, and the exhaust ports P3 and P4 are adjacent to each other. However, the third exhaust port P3
Is suppressed from flowing into the fourth exhaust port P4 side, and exhaust interference is prevented.

Next, the exhaust gas generated by 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 part 28 from the opening 37 and the small hole 44 and is sent from the collecting pipe part 28 to the exhaust pipe. The above-described operation is repeated, and the exhaust gas flows into the first branch pipe portion 24 by the combustion in the first cylinder # 1.

At this time, the exhaust sequence is continuous between the second exhaust port P2 and the first exhaust port P1,
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, thereby preventing exhaust interference and preventing a reduction in output torque.

On the other hand, when the engine 100 is started, the temperatures of the outer case 4 and the partition tube 6 are low, and the heat of the exhaust gas is taken by the outer case 4 and the partition tube 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 recovers in a short time, and the catalyst purification efficiency can be improved.

During the operation of the engine 100, the first, fourth
The exhaust gas from the cylinders # 1 and # 4 is supplied to the first and third branch pipes 2
4, 26, flow into the collecting pipe section 28,
First and second chambers 2 partitioned by the reinforcing members 40 and 42 of FIG.
8a and 28b have a cross-sectional area of the first and third branch pipe portions 24 and 26.
, The exhaust gas expands and is silenced by the expansion and resonance effects. The cross-sectional area of the first and second chambers 28a and 28b may be set to an appropriate cross-sectional area by an experiment or the like so that the noise reduction effect is exhibited.

The exhaust gas from the second and third cylinders # 2 and # 3 passes through the inside of the partition pipe 6 and from the opening 37 and the small hole 44 to the first and second chambers 28a and 28b of the collecting pipe section 28. Although the gas flows in, the exhaust gas expands because the sectional area of the collecting pipe portion 28 is large. Sound waves accompanying the exhaust are reflected from the inner wall of the outer case 4 to the inner wall, interfere with each other, and are attenuated. As described above, since the sound can be silenced by the exhaust manifold 1, a muffler (not shown) can be reduced in size, and 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 to 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. Instead, the partition pipes are provided at the first exhaust port P1 and the fourth exhaust port P4. And may be provided. That is, the present invention can be implemented if the exhaust order is continuous and both exhaust ports are provided with partition pipes in adjacent exhaust ports.

Next, an exhaust manifold according to a second embodiment different from the above-described embodiment will be described with reference to FIGS. Note that the same members as those in the above-described embodiment are denoted by the same reference numerals, and detailed description is omitted. In the second embodiment, a first partition tube 50 and a second partition tube 52 are provided in the outer case 4. The first partition tube 50 has first and second branch pipe portions 54 and 56 similarly to the above-described partition tube 6.
And a merging pipe section 58 connected to the first and second branch pipe sections 54 and 56.

The first branch pipe section 54 is connected to the second exhaust port P2, and the second branch pipe section 56 is connected to the third exhaust port P3. The other end of the merging tube portion 58 extends until it reaches the collecting tube portion 28, and an opening 60 is arranged in the collecting tube portion 28. The first branch pipe part 62,
64, and a merging pipe section 66 connected to the first and second branch pipe sections 62, 64 are provided. The first branch pipe part 62 is connected to the first exhaust port P1, and the second branch pipe part 64 is connected to 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 disposed therein.

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

Next, the operation of the exhaust manifold according to 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 supplied to separate first and second branch pipe portions 5 respectively.
4, 56, 62, 64, and merge pipe sections 58, 66,
Since it flows out to the exhaust pipe through the collecting pipe section 28, exhaust interference can be more effectively prevented. In addition, the first and second partition tubes 5
By reducing the thickness of the plates 0, 52, the heat capacity can be reduced, and the temperature of the exhaust gas recovers in a short time when the engine is started.

Further, when flowing into the collecting pipe section 28 from both the merging pipe sections 58 and 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 section 28 may be set to an appropriate cross-sectional area so that a noise reduction effect is exhibited.

The present invention is not limited to such an embodiment at all, and can be implemented in various modes without departing from the gist of the present invention.

[0038]

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

[Brief description of the drawings]

FIG. 1 is a front view of an exhaust manifold as one embodiment of the present invention.

FIG. 2 is a plan view of an exhaust manifold according to the embodiment.

FIG. 3 is a partially cutaway side view of the exhaust manifold of the present embodiment.

FIG. 4 is a sectional view taken along the line AA in FIG. 2;

FIG. 5 is a sectional view taken along the line BB of FIG. 3;

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

FIG. 7 is a plan view of an exhaust manifold according to a second embodiment.

FIG. 8 is a side view showing a part of an exhaust manifold according to a second embodiment of the present invention.

FIG. 9 is a sectional view taken along the line CC in FIG. 8;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Exhaust manifold 2 ... Large flange 4 ... Outer case 6 ... Partition pipe 8 ... Small flange 10-13 ... Through-hole 24 ... 1st branch pipe part 25 ... 2nd branch pipe part 26 ... 3rd branch pipe part 28 ... Assembly Pipe section 28a: first chamber 28b: second chamber 34, 54, 62 first branch pipe section 36, 56, 64 second branch pipe section 37, 60, 68 opening 38, 58, 66 ... junction pipe section 40, 42, 74 ... reinforcement member 44, 70, 72 ... small hole 50 ... first partition tube 52 ... second partition tube 100 ... engine

Claims (6)

[Claims] In an exhaust manifold, an exhaust pipe is connected to a collecting pipe section in which branch pipe sections connected to respective exhaust ports of a multi-cylinder engine are collected, and exhaust gas exhausted from each exhaust port is sent to the exhaust pipe. An outer case in which the branch pipe portion and the collecting pipe portion are formed, and a cross-sectional area of the collecting pipe portion is formed larger than a cross-sectional area of the exhaust port; and a partition provided in the outer case. An exhaust manifold, wherein one end of a pipe communicates with an exhaust port, and the other end of the partition pipe extends from inside the branch pipe section to reach the inside of the collecting pipe section, and is opened in the collecting pipe section. . 2. An exhaust pipe connected to a collecting pipe section in which branch pipe sections connected to first to fourth exhaust ports of a four-cylinder engine are collected, and exhaust gas exhausted from the first to fourth exhaust ports. An exhaust manifold that sends exhaust gas to an exhaust pipe, wherein the order of exhaust from the first to fourth exhaust ports is first, third, fourth, and second, and the outer pipe in which the branch pipe portion and the collecting pipe portion are formed. A case, and a cross-sectional area of the collecting pipe portion is formed larger than a cross-sectional area of the exhaust port. One end of a partition pipe provided in the outer case communicates with the second and third exhaust ports, respectively. An exhaust manifold, wherein the other end sides of the partition pipes are gathered, extended from inside the branch pipe section to reach the inside of the collecting pipe section, and opened in the collecting pipe section. 3. One end of another partition pipe provided in the outer case is communicated with first and fourth exhaust ports, respectively, and the other ends of the partition pipes are gathered so that the inside of the branch pipe and the inside of the collecting pipe portion are formed. 3. The exhaust manifold according to claim 2, wherein the exhaust manifold is extended until the exhaust pipe reaches the opening, and is opened in the collecting pipe portion. 4. The exhaust according to claim 2, 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. A sectional area of the partition tube is substantially equal to a sectional area of the exhaust port, and a reinforcing member is provided between the partition tube and the outer case. The described exhaust manifold. 6. The exhaust manifold according to claim 1, wherein a number of small holes are formed in the partition pipe in the collecting pipe.