JP2000248930A - Exhaust manifold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust manifold, capable of restraining exhaust gas temperature just after engine starting from being lowered down, quickly increas ing catalyst temperature, and of preventing exhaust interference. SOLUTION: This manifold is provided with a first through a third branch pipe parts 24 through 26 connected with the first through fourth exhaust ports 24 through 26 of a four cylinder engine 100, and an outer case 4 provided with a collecting pipe part 28 collecting the first through third branch pipes 24 through 26. The order of exhaustion from the first to the forth exhaust port is #1 to #3 to #4 to #2, and a partitioned pipe 6 communicated with the second and third exhaust ports P2 and P3 out of the exhaust ports P1 through P4 mutually adjacent and continuous in exhaustion order, is provided for a space from the inside of the second branch pipe part 25 over to the inside of a collecting pipe part 28, and the partitioning pipe 6 is opened in the collecting pipe part 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 shown in FIG. 7, exhaust gas discharged from an engine 100 is passed through an exhaust manifold 101 and an exhaust pipe 102 to a catalytic converter 10.
3 and purified by the catalyst in the catalytic converter 103, and then exhausted through the muffler 104. Since the catalyst is activated at a temperature of about 350 ° C. or more, the engine 10
At the start of 0, some time is required until the catalyst is activated due to the low temperature of the catalyst.

[0003] Therefore, the temperature of the exhaust gas sent from the engine 100 to the catalytic converter 103 is suppressed from decreasing, and
In order to activate the catalyst as soon as possible, we are trying to reduce the heat capacity of the exhaust manifold. For example, FIG.
In the case of the four-cylinder engine 100 shown in FIG. 1, the exhaust manifold 101 is formed of a double-pipe structure including thin first to fourth inner pipes 111 to 114 connected to the respective exhaust ports, and a reinforcing case 120 covering these. And

[0004] First to fourth inner pipes 111 to 11
4 are first cylinder # 1 to fourth cylinder # 4 of engine 100, respectively.
It is connected to cylinder # 4. The ignition order is for the first cylinder # 1,
The third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 2. The first inner pipe 111 and the fourth inner pipe 114 are connected to an exhaust pipe to prevent exhaust interference. . Further, the second inner pipe 112 and the third inner pipe 113 are connected to each other and connected to an exhaust pipe.

Accordingly, the first to fourth heat exchangers having a small heat capacity are used.
Since the inner pipes 111 to 114 quickly reach the saturation temperature due to the high-temperature exhaust gas, the exhaust gas discharged at the time of starting the engine has less heat taken away when passing through the inside of the exhaust manifold 101, and suppresses the temperature decrease of the exhaust gas. be able to. Further, since exhaust interference is prevented, it is possible to suppress a decrease in power performance.

[0006]

However, in such a conventional apparatus, the first to fourth inner pipes 111 are not provided.
Since the shapes of the reinforcing cases manufactured according to the shapes of the first to fourth inner pipes 111 to 114 become complicated at the same time, the processing steps become complicated, and Therefore, there is a problem that the surface area is large, heat is radiated through the reinforcing case, and the suppression of the temperature decrease of the exhaust gas is not sufficient.

An object of the present invention is to provide an exhaust manifold capable of suppressing a decrease in the temperature of exhaust gas immediately after the start of an engine, rapidly raising the temperature of a catalyst, and preventing exhaust interference.

[0008]

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 exhaust manifold, wherein a partition pipe communicating with one of the continuous adjacent exhaust ports is provided from the inside of the branch pipe section to the inside of the collecting pipe section, and the partition pipe is opened in the collecting pipe section. That is it. The length of the partition tube is preferably a length that prevents exhaust interference. After adjoining the said partition pipes, it is good also as a structure opened to the inside of the said collection pipe part.

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 that sends the air to the exhaust pipe, the order of exhaust from the first to fourth exhaust ports is first, third, fourth, and second, and the exhaust order communicates with one of adjacent exhaust ports that are continuous. An exhaust manifold, wherein a partition pipe is provided from the inside of the branch pipe section to the inside of the collecting pipe section, and the partition pipe is opened in the collecting pipe section.

[0010] The partition pipe communicating with the second and third exhaust ports may be provided in the branch pipe part communicating with the second and third exhaust ports. Further, 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.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, reference numeral 1 denotes an exhaust manifold, which is used in a four-cylinder engine 100 in this embodiment. The engine 100
First to fourth exhaust ports P1 to P4 are provided to communicate 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 2.

The exhaust manifold 1 has a large flange 2, an outer case 4, a partition pipe 6, and a small flange 8. As shown in FIG. 2, the large flange 2 has four through holes 10 corresponding to the first to fourth exhaust ports P1 to P4.
13 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. 5, annular projections 20 to 23 protruding 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 in a hollow shape by a molding process using a press, and the collecting pipe portion 2 is formed from the first to third branch pipe portions 24 to 26.
It is formed such that the cross-sectional area decreases toward the side 8.

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 thickness, and is formed to be 1.5 mm in the present embodiment.

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

As shown in FIG. 2, the first branch pipe portion 24 is
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 has a thickness of 0.8 mm in this embodiment.
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.

As shown in FIG. 2, the first and second branch pipe sections 34 and 36 are separated by a concave section 40 in which the front and back sides of the partition pipe 6 are recessed and overlapped.
Reference numerals 4 and 36 are formed in a substantially circular shape. And the first,
The second branch pipes 34 and 36 are joined at a joining pipe 38, and an opening 37 is formed at the other end of the joining pipe 38 (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. As shown in FIG. 5, the outer case 4 is covered on the partition pipe 6, and the second branch pipe part 25 of the outer case 4 is formed with the first and second branch pipe parts 34 and 36 as shown in FIG. From above, both annular projections 21,
22. Then, welding is performed along the outer periphery of the outer case 4, and the outer case 4 is attached to the large flange 2.
And the partition pipe 6 are integrally attached.

The first exhaust port P1 has a through hole 10 and a first exhaust port P1.
The branch pipe portion 24 communicates with the opening 29 via 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 provided with 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 exhaust gas is sent from the opening 29 to the exhaust pipe through the third branch pipe section 26 and the collecting pipe section 28, which communicate with the opening 29.

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 the length from the large flange 2 to the opening 37 of the partition pipe 6 is such that exhaust interference can be prevented. The length is formed. Each exhaust port P
The cross-sectional area of the flow passage that communicates between 1 to P4 and the opening 29 of the outer case 4 is formed so as to be substantially the same or slightly larger at each location.

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 collecting pipe section 28 and is sent to an exhaust pipe (not shown). next,
Exhaust gas generated by combustion in the third cylinder # 3 flows from the third exhaust port P3 through the through hole 12 into the second branch portion 36 of the partition tube 6. Then, it passes through the inside of the partition tube 6 and passes through the opening 37.
From the collecting pipe portion 28, and is sent from the collecting pipe portion 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. Then, it passes through the collecting pipe section 28 and is sent to an exhaust pipe (not shown). At that time, the third cylinder #
Combustion continues between the third and fourth cylinders # 4, the order of exhaust continues between the third exhaust port P3 and the fourth exhaust port P4, and both exhaust ports P3 and P4 are adjacent. However, the partition pipe 6 suppresses the exhaust gas from the third exhaust port P3 from flowing into the fourth exhaust port P4.
Exhaust interference is prevented.

Next, the exhaust gas from 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 part 28 from the opening 37 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 and prevents exhaust interference.

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. In addition, the outer case 4 may be accommodated in the outer case 4 by storing the partition pipe 6 having a short length.
Also has a small surface area, so that little heat is radiated to the outside when the outer case 4 is started.

Accordingly, as shown in FIG. 6, the temperature of the exhaust gas passing through the exhaust manifold 1 recovers in a short time, and a decrease in the exhaust gas temperature is suppressed. That is, when the exhaust manifold 1 of the present embodiment is used, the time required for the exhaust gas temperature to recover to 350 ° C. is shorter than in the case of the conventional double-pipe exhaust manifold indicated by a dashed line.

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.

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

[0031]

As described above in detail, the exhaust manifold of the present invention has a small heat capacity and a small surface area, so that when the engine is started, the temperature of the exhaust gas passing through the exhaust manifold recovers in a short time, and the temperature of the exhaust gas is reduced. The effect is obtained that the reduction is suppressed 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, 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 sectional view taken along the line AA of FIG.

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 BB of FIG. 3;

FIG. 5 is an exploded view of the exhaust manifold according to the embodiment.

FIG. 6 is a graph showing temperature characteristics of the exhaust manifold of the present embodiment.

FIG. 7 is an explanatory diagram showing an exhaust system of the internal combustion engine.

FIG. 8 is a front view of a conventional exhaust manifold.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,101 ... Exhaust manifold 2 ... Large flange 4 ... Outer case 6 ... Partition tube 8 ... Small flange 10-13 ... Through hole 14-18 ... Mounting hole 20-23 ... Circular projection 24 ... First branch pipe part 25 ... Second branch pipe part 26 ... Third branch pipe part 28 ... Collecting pipe part 30, 32 ... Depression part 34 ... First branch pipe part 36 ... Second branch pipe part 37 ... Opening 38 ... Depression part 38 ... Confluence pipe part 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. A partition pipe communicating with one of adjacent exhaust ports having a continuous exhaust sequence is provided from the inside of the branch pipe part to the inside of the collecting pipe part, and the partition pipe is opened in the collecting pipe part. Exhaust manifold. 2. The exhaust manifold according to claim 1, wherein the length of the partition tube is a length that prevents exhaust interference. 3. The exhaust manifold according to claim 1, wherein, after the adjacent partition pipes are gathered, the partition pipe is opened in the collecting pipe part. 4. 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. The exhaust order from the first to fourth exhaust ports is first, third, fourth, and second, and the exhaust manifold communicates with one of adjacent exhaust ports in a continuous exhaust order. An exhaust manifold, wherein a partition pipe is provided from the inside of the branch pipe section to the inside of the collecting pipe section, and the partition pipe is opened in the collecting pipe section. 5. The partition pipe according to claim 4, wherein the partition pipe communicating with the second and third exhaust ports is provided in the branch pipe part communicating with the second and third exhaust ports. Exhaust manifold. 6. The exhaust system according to claim 4, wherein the branch pipe portion communicates with the first exhaust port, the second and third exhaust ports, and the fourth exhaust port, respectively. Manifold.