JP2005233045A - Exhaust manifold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust manifold, in which engine performance is achieved to the utmost by composing connection pipes to have equal pipe length without conducting complicated bending work to the connection pipes. <P>SOLUTION: In this exhaust manifold, the connection pipes 2-4 are connected from exhaust ports in a multiple cylinder engine to a collecting part 5 in an exhaust pipe through bent parts. The connection pipes 2-4 are formed to have equal pipe length. Insert length A1-A3 of the connection pipes 2-4 into the collecting part 5 are varied. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust manifold in which a plurality of connecting pipes have a curved portion from an exhaust port of a multi-cylinder engine and are connected to a collective portion of the exhaust pipe.

2. Description of the Related Art Conventionally, an exhaust manifold of a multi-cylinder engine of an automobile has a structure in which a plurality of connecting pipes have a curved portion from an exhaust port of the multi-cylinder engine and are connected to a collective portion of exhaust pipes (Patent Documents 1 and 2). reference).
For example, in the case of an in-line four-cylinder engine, the exhaust manifold is composed of four connecting pipes, and each connecting pipe has a bent portion from each exhaust port of the engine and is gathered into one at the collecting portion of the exhaust pipe. ing.
In general, it is desirable that the lengths of the connecting pipes are equal in order to maximize the performance of the engine.
JP-A-8-28261 JP 2003-83062 A

  However, in the inventions described in Patent Documents 1 and 2, the downstream end portions of the connection pipes are connected in a state of being inserted into the assembly portion with the same insertion allowance. In order to make them equal, it is necessary to bend the connecting pipes in a three-dimensionally complex manner and adjust the length. For example, the connecting pipe with the shortest distance between the exhaust port and the collecting pipe has the above-mentioned distance. Since it is necessary to secure the length so as to bypass by bending with a small curvature in order to make it equal to the long connecting pipe, it takes time to bend and weld to form the curved portion of each connecting pipe. Therefore, there is a problem that the production efficiency is lowered.

  Moreover, since the connecting pipe having a complicated curved portion has a large exhaust gas resistance, it leads to a reduction in engine output.

  The problem to be solved by the present invention is to make the length of each connecting pipe equal without making a complicated bending process for each connecting pipe by making the insertion allowance of each connecting pipe into the assembly portion different. The purpose is to provide an exhaust manifold that can maximize the performance of the engine.

  In order to solve the above-mentioned problem, in the invention according to claim 1, in the exhaust manifold in which the plurality of connecting pipes have curved portions from the exhaust ports of the multi-cylinder engine and are connected to the collective portions of the exhaust pipes, It is characterized in that the tube lengths are formed to be equal and the insertion allowances of the connecting pipes into the collecting portion are different.

  According to a second aspect of the present invention, in the exhaust manifold according to the first aspect, the connection pipes are arranged in the same plane.

  According to a third aspect of the present invention, in the exhaust manifold according to the first or second aspect, the position of the end portion of the collecting portion into which each connecting pipe is inserted is different for each connecting pipe, The peripheral edge of each end portion and each connecting pipe are fixed by welding.

In the exhaust manifold according to claim 1, since the pipe lengths of the respective connection pipes are formed to be equal and the insertion allowances of the respective connection pipes into the collective portion are different, the curvature of the curved portion of each connection pipe is conventionally increased. Therefore, it is possible to simplify the bending process for forming the curved portion, and to reduce the labor required for manufacturing this type of exhaust manifold.
In addition, since the resistance of the exhaust gas in each connecting pipe is reduced, the engine performance can be maximized.
Further, exhaust interference due to exhaust gas is less likely to occur in the gathering portion than in the conventional invention.

In the exhaust manifold according to claim 2, since the connecting pipes are arranged side by side in the same plane, the curved portions of the connecting pipes can be formed in substantially the same shape. Efficient exhaust gas distribution can be realized by equalizing the gas resistance.
In addition, the exhaust manifold can be made compact.

  The exhaust manifold according to claim 3, wherein the position of the end portion of the collective portion into which each connection pipe is inserted is different for each connection pipe, and the peripheral edge of each end portion of the collective portion and each connection Since the pipes are fixed by welding, the welding locations where the connecting pipes and the gathering portions are fixed can be dispersed, and the thermal stress applied to the weld locations can be reduced to improve the durability.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1 will be described below.
1 is a plan view of an exhaust manifold according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line S2-S2 of FIG.

  As shown in FIG. 1, the exhaust manifold of the first embodiment includes a head flange 1 fixed to an engine (not shown), a plurality of connection pipes 2 to 4, and a collecting portion 5 connected to an exhaust pipe (not shown). Is the main component.

  The head flange 1 is fixed to one side of the V-type 6-cylinder engine, and has openings 1a to 1c for communicating upstream ends of the connecting pipes 2 to 4 with the exhaust ports of the engine. It has a plate shape.

  The connecting pipes 2 to 4 are formed in the same diameter with a circular cross-sectional shape, and the pipe lengths thereof are equally formed.

  Further, the upstream end portions of the connecting pipes 2 to 4 are welded and fixed while being fitted into the corresponding openings 1 a to 1 c of the head flange 1, and the intermediate portions are bent toward the collecting portion 5. Accordingly, the curved portions 6 to 8 are formed.

Further, as shown in FIG. 2, the downstream end portions 9 to 11 of the connection pipes 2 to 4 are respectively processed and inserted into the end portions of the assembly portion 5 having a racetrack-shaped cross-sectional shape. 4 are arranged in parallel with being arranged in the same plane.
Thereby, the shape and the curvature of the curved parts 6-8 in the said connecting pipes 2-4 are formed substantially equal, and what each changed the cutting position of the both ends is employ | adopted.

The insertion allowances A1 to A3 of the downstream ends 9 to 11 of the connecting pipes 2 to 4 are different from each other, and in this embodiment, from the openings 1a to 1c (exhaust ports) of the head flange 1. The position of the end portion 5a of the collective portion 5 is provided in accordance with the downstream end portion 9 of the connecting pipe 2 having the longest distance to the end portion 5a of the collective portion 5, whereby the difference between the insertion allowances A1 to A3 is It is also a difference in distance from the openings 1a to 1c (exhaust ports) in the connecting pipes 2 to 4 to the end 5a of the collective portion 5.
The side ends of the connecting pipes 2 to 4 are fixed by welding X (shown by bold lines), and the periphery of the end portion 5a of the collecting part 5 and the outer periphery of each connecting pipe 2 to 4 are welded Y. It is fixed at (shown with a thick line).

  In the exhaust manifold configured as described above, the difference in distance from the openings 1a to 1c (exhaust ports) in the connection pipes 2 to 4 to the end 5a of the collection part 5 is determined by the collection in the connection pipes 2 to 4. The insertion allowances A1 to A3 of the portion 5 can be eliminated, and as a result, the curvatures of the curved portions 6 to 8 of the connecting pipes 2 to 4 can be formed larger than those of the conventional invention, and the curved portions 6 to 8 are processed. At the same time, the labor of the engine can be maximized by reducing the lengths of the connecting pipes 2-4.

  Moreover, since the shape of the said curved parts 6-8 and its curvature are formed substantially equal, the exhaust resistance of the connecting pipes 2-4 becomes substantially equal, and distribution | circulation of ideal exhaust gas is attained.

  Further, because of the difference in the insertion allowances A1 to A3, the positions of the downstream end portions 9 to 11 of the connecting pipes 2 to 4 in the collecting portion 5 into which the exhaust gas flows are different. Can be avoided.

Example 2 will be described below.
The exhaust manifold according to the second embodiment is formed such that the positions of the end portions 5a of the collecting portions 5 into which the connecting pipes 2 to 4 are inserted are different for the respective connecting tubes 2 to 4, and the end portions 5a of the collecting portions 5 are formed. In the point which fixed the periphery and the connecting pipes 2-4 by welding, it is different from the said Example 1, and since it is the same about others, the same code | symbol is attached | subjected about the same structural member and the description is abbreviate | omitted.
FIG. 3 is a plan view of the exhaust manifold according to the second embodiment of the present invention.

As shown in FIG. 3, the exhaust manifold according to the second embodiment is formed such that the position of the end portion 5 a of the collecting portion 5 into which the connection pipes 2 to 4 are inserted is different for each connection pipe 2 to 4. .
Further, the peripheral edge of the end portion 5a of the collective portion 5 and the connection pipes 2 to 4 are fixed by welding Z (shown by a thick line).

  Therefore, the welding location where the connecting pipes 2 to 4 and the gathering portion 5 are fixed can be dispersed and formed in a wide range, and the thermal stress applied to the weld Z can be reduced to improve the durability.

Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included in the present invention.
For example, the number of connecting pipes 2 to 4 can be changed as appropriate according to the number of exhaust ports of the engine. For example, the number of connecting pipes 2 to 4 is also applicable.
Moreover, it is applicable also when connecting to the aggregate | assembly part 5 so that the extension line of the axial center of the connecting pipes 2-4 may cross | intersect.

It is a top view of the exhaust manifold of Example 1 of this invention. It is sectional drawing in the S2-S2 line | wire of FIG. It is a top view of the exhaust manifold of Example 2 of this invention.

Explanation of symbols

X, Y, Z Welding 1 Head flange 2, 3, 4 Connecting pipe 5 Collecting part 6, 7, 8 Curved part 9, 10, 11 Downstream end part

Claims (3)

In the exhaust manifold, a plurality of connecting pipes have curved portions from the exhaust port of the multi-cylinder engine and are connected to the collective portion of the exhaust pipe.
Forming equal lengths of the connecting pipes;
An exhaust manifold characterized in that the insertion allowance of the connecting pipes into the collecting portion is different. In the exhaust manifold according to claim 1,
An exhaust manifold in which the connection pipes are arranged in the same plane. The exhaust manifold according to claim 1 or 2,
Forming the position of the end portion of the collecting portion into which each connecting pipe is inserted to be different for each connecting pipe,
An exhaust manifold characterized in that a peripheral edge of each end portion of the gathering portion and each connection pipe are fixed by welding.

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