JP4169485B2 - Exhaust manifold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust manifold provided with an O ₂ sensor for controlling an air-fuel ratio.
[0002]
[Prior art]
Conventionally, as this type of exhaust manifold, for example, one disclosed in Japanese Patent Laid-Open No. 9-236012 is known.
An example is shown in FIG.
The exhaust manifold 1 includes a flange 2 that is fixed to the exhaust side of the engine, four branch pipes 3 that have a substantially sectoral cross section connected to the flange 2, and a collecting container 4 that collects these branch pipes 3. It is composed of
[0003]
In the collective container 4, an O ₂ sensor 5 is attached to the root portion of the branch pipe 3.
A manifold converter 6 composed of a cylindrical container having an elliptical cross section is connected to the downstream side of the collecting container 4.
[0004]
A metal catalyst carrier 7 for purifying exhaust gas is accommodated in the manifold converter 6.
According to the exhaust manifold 1 described above, the exhaust gas discharged from the engine is guided from the plurality of branch pipes 3 into the collecting container 4, and the oxygen concentration in the exhaust gas is measured by the O ₂ sensor 5. Can be introduced.
[0005]
Thereafter, the exhaust gas is purified by the metal catalyst carrier 7 and flows out from the exhaust gas outlet 8, for example, is guided to a silencer (not shown), and after being silenced, is discharged into the atmosphere.
[0006]
[Problems to be solved by the invention]
However, in the above-described conventional exhaust manifold 1, as shown in FIG. 5, since the O ₂ sensor 5 is attached to the root portion of the branch pipe 3, the exhaust gas flowing into the collecting container 4 from each branch pipe 3. It was difficult to accurately measure the oxygen concentration in the exhaust gas.
[0007]
Further, in the conventional exhaust manifold 1, as shown in FIG. 6, each branch pipe 3 is bound into a circular cross section and inserted into the collecting container 4, and the end faces of the branch pipes 3 are welded to each other. There was a problem that it was difficult to reliably fix the wall 3a of the tube 3 by welding.
Furthermore, a large gap 3b is formed in the central portion where the branch pipes 3 are joined, which may cause a reduction in the joint strength between the branch pipes 3.
[0008]
The present invention has been made to solve such conventional problems, and an object of the present invention is to provide an exhaust manifold capable of evenly applying exhaust gas from each branch pipe to the O ₂ sensor.
Another object of the present invention is to provide an exhaust manifold capable of facilitating welding between the branch pipes.
[0009]
[Means for Solving the Problems]
According to the first aspect of the present invention, a plurality of branch pipes, a collecting container to which a tip portion of each branch pipe is attached, and an extension direction of two adjacent branch pipes among the plurality of branch pipes are positioned. And an O ₂ sensor provided in the collecting container, and between the branch pipes adjacent to the branch pipe so as to surround the branch pipe adjacent to the O ₂ sensor at the tip of each branch pipe. The rectifying plate is fixed while projecting from the tip of each branch pipe while being sandwiched .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention shown in the drawings will be described in detail.
1 to 3 show a main part of an exhaust manifold A according to an embodiment of the present invention .
The external structure of the exhaust manifold A according to this embodiment is the same as that of the conventional exhaust manifold 1 shown in FIG.
[0012]
In the present embodiment, the branch pipes 10, 11, 12, 13 consisting of four pipes having a substantially fan-shaped cross section are fixed to a flange whose upstream side is fixed to the exhaust side of the engine in the same manner as the conventional exhaust manifold 1, The downstream side is attached to the collecting container 20. An O ₂ sensor 30 is attached to the collecting container 20.
The distal end portions 10 a, 11 a, 12 a, and 13 a of the branch pipes 10, 11, 12, and 13 are bundled so as to have a substantially circular cross section and are fitted into the inlet 21 of the collecting container 20.
[0013]
At this time, in the present embodiment, two rectifying plates 15a and 15b and a connecting portion 15c that connects them in a substantially L shape so as to surround the wall portions 11b and 11c of the branch pipe 11 are connected to adjacent branch pipes. 12 and 13 are sandwiched between the wall portions 12c and 13b.
And the front-end | tip part 10a, 11a, 12a, 13a of branch pipe 10, 11, 12, 13 is each adjacent wall part 10b, 13c, 13b, 11c, 11b, 12c, 12b, 10c, and baffle plate 15a. 15b and the connecting portion 15c are fixed by welding.
[0014]
Here, the welding of the rectifying plates 15a and 15b and the coupling portion 15c is because the rectifying plates 15a and 15b and the coupling portion 15c protrude from the branch pipe 11, and therefore from the branch pipe 10 side and from the branch pipes 12 and 13 side, respectively. Since it is performed from two directions, the welding operation is easier and the welding strength can be increased as compared with the welding of the end faces of the end portions 10a, 11a, 12a, 13a of the branch pipes 10, 11, 12, 13.
[0015]
In addition, a large gap (corresponding to the gap 3b in FIG. 5) is formed in the center of the joint portion of each branch pipe 10, 11, 12, 13 as in the prior art, but each branch pipe 10, 11, 12, 13 and The branch pipes 10, 11, 12, and 13 are firmly coupled by welding with the rectifying plates 15a and 15b and the coupling portion 15c. Therefore, there is no risk of causing a conventional problem.
[0016]
On the other hand, the O ₂ sensor 30 is attached to a mortar-shaped seat 31 provided in the collecting container 20 so as to be positioned in the extending direction of the branch pipes 11 and 13.
In the present embodiment, the rectifying plate 15 a located between the branch pipes 11 and 13 is attached to the O ₂ sensor 30 with a slight angle.
According to the exhaust manifold A according to the present embodiment configured as described above, when the exhaust gas discharged from the engine is led from the four branch pipes 10, 11, 12, 13 into the collecting container 20, the first The exhaust gas discharged from the branch pipe 10 communicating with the cylinder is guided toward the O ₂ sensor 30 by the rectifying plates 15a and 15b, and the exhaust gas discharged from the branch pipe 11 communicating with the second cylinder is guided by the rectifying plates 15a and 15b. O ₂ is directed towards the sensor 30, the exhaust gas discharged from the branch pipe 12 to contact the third cylinder is guided towards the O ₂ sensor 30 rectifying plates 15a, by 15b, the branch pipe to contact the fourth cylinder 13 The exhaust gas discharged from the air is guided toward the O ₂ sensor 30 by the rectifying plate 15b. That is, the exhaust gas discharged from the four branch pipes 10, 11, 12, and 13 is all guided toward the O ₂ sensor 30 by the rectifying plates 15a and 15b, and may hit the O ₂ sensor 30 evenly. It becomes possible.
[0017]
In the above embodiment, the case where the rectifying plates 15 a and 15 b are provided so as to surround the branch pipe 11 has been described, but the rectifying plates 15 a and 15 b may be provided so as to surround the branch pipe 13.
Further, the size, the mounting angle, and the like of the rectifying plates 15a and 15b vary depending on the exhaust manifold to be applied, and thus are appropriately changed so that a preferable exhaust gas flow can be controlled.
[0018]
Further, the length of insertion of the rectifying plates 15a, 15b and the coupling portion 15c into the branch pipes 10, 11, 12, 13 may be as long as the rise of the inlet 21 of the collecting container 20.
Furthermore, in the present embodiment, the case where the manifold converter is provided on the downstream side as in the conventional case has been described. However, the present invention is not limited to this and can be applied to a normal exhaust manifold not provided with a manifold converter. Nor.
[0019]
【The invention's effect】
As described above, according to the present invention, since the rectifying plate is provided so as to protrude at the downstream end of the branch pipe, the exhaust gas flow can be controlled by the rectifying plate, and the exhaust gas from each branch pipe can be controlled. It became possible to apply evenly to the O ₂ sensor. In addition, since the current plate is sandwiched and fixed by welding at the downstream end of the branch pipe, welding between the branch pipes can be facilitated.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of an exhaust manifold according to an embodiment of the present invention.
FIG. 2 is a perspective view in which a part of the exhaust manifold of FIG. 1 is cut away.
FIG. 3 is a bottom view in which a part of the exhaust manifold of FIG. 1 is cut away;
FIG. 4 is a front view showing a conventional exhaust manifold.
5 is a cross-sectional view of the exhaust manifold of FIG.
6 is an end view showing a branch pipe of the exhaust manifold of FIG. 4. FIG.
[Explanation of symbols]
A Exhaust manifold 10, 11, 12, 13 Branch pipes 10a, 11a, 12a, 13a Tip portions 10b, 10c, 11b, 11c, 12b, 12c, 13b, 13c Wall portions 15a, 15b Rectifier plate 15c Joint portion 20 Collecting vessel 30 O ₂ sensor

Claims (1)

A plurality of branch pipes, a collection container to which a tip portion of each branch pipe is attached , and provided in the collection container so as to be positioned in the extending direction of two branch pipes adjacent to each other among the plurality of branch pipes With O ₂ sensor,
The tip of each branch pipe is sandwiched between branch pipes adjacent to the branch pipe so as to surround the branch pipe adjacent to the O ₂ sensor, and protrudes from the tip of each branch pipe to rectify. An exhaust manifold characterized by a fixed plate.

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