JP2010084639A - Intake manifold for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake manifold for an internal combustion engine which can improve combustion efficiency by suppressing the influence to intake flow due to the introduction of blow-by gas. <P>SOLUTION: A gas introduction port 21 of blow-by gas to an intake pipe 12 is opened in a pipe wall 12a in a downstream part on an inner corner side of a first bend section 18, opened in a position deviated in a width direction of the pipe wall 12a on the inner corner side in the intake pipe 12 having substantially elliptical flow path cross section, and opened in the pipe wall 12a of a part facing a low-speed area of intake flow in the intake pipe 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an intake manifold having a structure in which a gas inlet for introducing blow-by gas is opened in each intake pipe in an internal combustion engine.

  Conventionally, this type of technique includes an intake manifold described in Patent Document 1, for example. As shown in FIG. 9, the intake manifold includes a flange portion 60 that is fixed to a cylinder block of the internal combustion engine, and a parallel groove 61 that serves as a blow-by gas passage is formed inside the flange portion 60. Branch branches 63 corresponding to the respective port portions 62 are provided. Accordingly, the blow-by gas is sucked into the port portion 62 through the parallel groove 61 and the branch groove 63 and sent into the combustion chamber of the internal combustion engine.

In Patent Document 2, as shown in FIG. 10, a box 51 including a part of the pipe walls of a plurality of intake pipes 50 is formed integrally with an intake manifold 52, and the wall of the intake pipe 50 in the box 51 is formed. A configuration in which a communication hole 53 is formed is disclosed. The box 51 is provided with a negative pressure extraction port 54 for supplying a negative pressure introduced from the intake pipe 50 into the box 51 to a brake booster (not shown). Each communication hole 53 is formed in a pipe wall on the opposite side to the bending direction on the downstream side of the bending portion 50 a in the intake pipe 50.
Japanese Unexamined Patent Publication No. 2004-36504 (pages 3 to 5 and FIGS. 1 to 4) Japanese Patent Laid-Open No. 2002-256991 (Patents 2, 3 and 1 to 3)

  However, in the configuration described in Patent Document 1, since the branch groove 63 of the parallel groove 61 is positioned in the immediate vicinity of the intake port of the combustion chamber, the intake air flows from the branch groove 63 and the branch groove 63. It is easily affected by the blow-by gas that is introduced, and there is a risk of lowering combustion efficiency.

  The configuration described in Patent Document 2 is not a configuration for introducing blow-by gas. However, when the blow-by gas is introduced into the box 51 and the blow-by gas is introduced into the intake pipe 50 from the communication hole 53, the communication is not possible. Since the hole 53 is located on the outer corner side of the curved portion 50a of the intake pipe 50, the intake flow is affected. For this reason, like the above-mentioned Patent Document 1, there is a risk of a reduction in combustion efficiency.

  The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide an intake manifold for an internal combustion engine that can suppress the influence on the intake air flow due to the introduction of blow-by gas and improve the combustion efficiency.

  In order to achieve the above object, an invention according to claim 1 is directed to an intake manifold of an internal combustion engine in which a gas inlet for introducing blow-by gas is opened in each intake pipe. It is characterized in that an opening is made in the pipe wall of the portion facing the low speed region of the intake air flow in the intake pipe.

The invention according to claim 2 is characterized in that a curved portion is formed in the intake pipe, and the gas inlet is opened at a downstream portion on the inner corner side of the curved portion.
The invention according to claim 3 is characterized in that the intake pipe is formed with a curved portion that curves in the same direction at two locations, and the gas inlet is opened in a straight portion between the curved portions. To do.

The invention described in claim 4 is characterized in that a gas introduction chamber for blow-by gas is formed outside the pipe wall of each intake pipe, and the gas introduction port is arranged in the gas introduction chamber.
The invention described in claim 5 is characterized by being configured by combining members formed of synthetic resin.

(Function)
In this invention, when the blow-by gas is introduced into the intake pipe from the gas inlet opening in the pipe wall of the part facing the low-speed area of the intake flow in the intake pipe, the pipe of the part facing the high-speed area of the intake flow The influence on the intake air flow is smaller than when blow-by gas is introduced into the intake pipe from the gas inlet port opened in the wall.

  Further, since the intake air flow that has passed through the curved portion approaches the outer corner side due to inertia, the flow velocity of the intake air flow in the downstream portion of the curved portion of the intake pipe is slower on the inner corner side than on the outer corner side. Therefore, when the blow-by gas is introduced into the intake pipe from the gas inlet port opened to the downstream portion on the inner corner side of the curved portion, the blow-by gas is introduced into the intake pipe from the gas inlet port opened to the downstream portion on the outer corner side. The effect on the intake air flow is smaller than when introducing.

  Further, when two curved portions that are curved in the same direction are formed in the intake pipe, the intake flow flows along the outer corner side at the straight portion between the two curved portions. As a result, the flow velocity of the intake air flow in the straight portion is slower on the inner corner side than on the outer corner side. Therefore, when blow-by gas is introduced into the intake pipe from the gas inlet port opened to the inner corner side in the straight portion between the two curved portions, it is introduced from the gas inlet port opened to the outer corner side in the straight portion. The effect on the intake air flow is smaller than that of the case.

  In addition, a gas introduction chamber for blow-by gas is formed outside the pipe wall of each intake pipe, and a gas introduction port is arranged in the gas introduction chamber, so that the gas introduction port can be easily positioned at a position biased in the width direction of the pipe wall. The structure for opening and supplying the blow-by gas to each intake pipe is simplified.

  According to the present invention, it is possible to suppress the influence on the intake air flow due to the introduction of the blow-by gas and to improve the combustion efficiency.

Next, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the intake manifold 10 includes a surge tank 11 connected to an upstream air cleaner via a throttle valve (not shown), a plurality of intake pipes 12 branched from the surge tank 11, A flange portion 13 for connecting each intake pipe 12 to a cylinder block of the internal combustion engine Eg is provided. The intake manifold 10 is configured by combining four molded members made of synthetic resin, that is, a manifold body 14, a tank cover 15, an intake pipe housing 16, and a gas introduction chamber housing 17.

  As shown in FIG. 3, each intake pipe 12 includes a first curved portion 18 that changes the direction of the intake air flow at an angle of 90 ° or more, and a second curved portion that curves in the same direction as the first curved portion 18 on the downstream side. Part 22. A straight portion 23 is formed between the first bending portion 18 and the second bending portion 22 in each intake pipe 12. Blow-by gas is supplied from the cylinder head of the internal combustion engine Eg to the downstream side of the first curved portion 18 of each intake pipe 12, that is, to the pipe wall 12 a on the inner corner side of both curved portions 18 and 22 in the straight portion 23. A gas introduction part 19 for introduction into the interior is provided. As shown in FIGS. 3 and 4, a gas introduction chamber 20 is defined in the gas introduction portion 19 by covering the outside of the pipe wall 12 a of each intake pipe 12 with the gas introduction chamber housing 17. In the pipe wall 12a of each intake pipe 12 facing the gas introduction chamber 20, a gas introduction port 21 that communicates the gas introduction chamber 20 with each intake pipe 12 is formed.

  As shown in FIGS. 5, 6, and 7 (a), the gas introduction port 21 includes an inclined surface 21 a in which the downstream edge of the intake pipe 12 is inclined downward from the outside of the intake pipe 12 toward the inside. Has been. Moreover, the edge part other than the said inclined surface 21a of the gas inlet 21 is made into the inclined surface 21b extended toward the inner side from the outer side of the intake pipe 12. As shown in FIG. Further, as shown in FIG. 8, the flow passage cross section of each intake pipe 12 has a substantially oval shape in which the inner corner side and the outer corner side of both curved portions 18, 22 are linear and both sides are arcuate. The gas inlets 21 are opened at positions deviated in the width direction of the straight tube wall 12a.

  The intake air sucked into the surge tank 11 from the air cleaner during the operation of the internal combustion engine is distributed to the intake pipes 12 and sucked into the combustion chambers of the internal combustion engine Eg. The blow-by gas introduced from the crank chamber of the internal combustion engine Eg into the gas introduction chamber 20 of the gas introduction unit 19 is introduced into the intake pipe 12 through the gas introduction ports 21. The flow velocity of the intake flow in the downstream portion of the first curved portion 18 in the intake pipe 12 is greater on the outer corner side of both curved portions 18 and 22 than on the inner corner side, as indicated by arrows in FIG. 3 due to the inertia of the intake flow. Will also be faster. In addition, the flow velocity of the intake air flow in the straight portion 23 is faster at the central portion in the width direction than on the width end portion side. In this embodiment, each gas introduction port 21 is opened on the inner wall side of both curved portions 18 and 22 and on the tube wall 12a at the end in the width direction, so blow-by gas passes through each gas introduction port 21. It is introduced in the low speed region of the intake flow. As a result, the influence on the intake air flow in the intake pipe 12 is suppressed, and the combustion efficiency is improved.

According to this embodiment, the following effects can be obtained.
(1) The gas inlet 21 of the blow-by gas to the intake pipe 12 is a downstream portion on the inner corner side of the first curved portion 18 in the intake pipe 12, and a straight portion 23 between the second curved portion 22. Opened. Therefore, since blow-by gas can be introduced into the low speed region of the intake flow, the influence of the blow-by gas on the intake flow can be suppressed. For this reason, the combustion efficiency of the internal combustion engine Eg can be improved.

  (2) The gas inlet 21 is opened at a position deviated in the width direction in the intake pipe 12 having a substantially elliptical cross section. Therefore, since blow-by gas can be introduced into the low speed region of the intake air flow, the influence on the intake air flow can be suppressed and the combustion efficiency of the internal combustion engine Eg can be improved in the same manner as described above.

  (3) The gas introduction chamber 20 is formed outside the tube wall 12 a of each intake pipe 12, and the gas introduction port 21 is disposed in the gas introduction port 21. Therefore, the gas inlet 21 can be easily opened at a position biased in the width direction of the pipe wall 12a, and the configuration for supplying blow-by gas to each intake pipe 12 can be simplified. .

  (4) The downstream edge of the gas inlet 21 is an inclined surface 21 a that is inclined downward from the outside of the intake pipe 12 toward the inside. With this configuration, the intake flow flowing through the intake pipe 12 is smoothly guided to the downstream side, and is prevented from flowing back into the gas introduction chamber 20 through the gas introduction port 21.

  (5) The edges of the gas introduction chamber 20 other than the inclined surface 21a are inclined surfaces 21b that expand from the outside to the inside of the intake pipe 12. With this configuration, the intake flow flowing in the intake pipe 12 is prevented from vortexing starting from the opening edge on the inner surface side of the gas introduction port 21, so that the disturbance of the intake flow can be effectively suppressed.

In addition, this embodiment can also be changed and embodied as follows.
In the intake manifold 10 in which the cross section of the intake pipe 12 is substantially circular, substantially elliptical, or rounded quadrangular, it is the downstream pipe wall on the inner corner side of the first curved part 18 and at the width end thereof. Open the gas inlet 21.

As shown by two-dot chain lines in FIGS. 6 and 8, two gas inlets 21 are provided at the width end of one intake pipe 12.
-As shown in FIG.7 (b), let the edge part of the downstream of the gas inlet 21 be the curved surface 21c which descents to the downstream.

-As shown in FIG.7 (c), incline the edge of the gas inlet 21 only to the downstream side.
A pipe connection portion is formed in each intake pipe 12, and blow-by gas is supplied to each intake pipe 12 through a pipe connected to the pipe connection section.

Hereinafter, the technical idea grasped from the embodiment will be described.
(1) In the intake manifold of the internal combustion engine according to claim 4, the downstream side portion (inclined surface 21a) of the intake pipe at the edge of the gas introduction port is inclined downward toward the downstream side of the intake pipe. An intake manifold for an internal combustion engine.

  (2) In the intake manifold of the internal combustion engine described in the technical idea (1), a portion (inclined surface 21b) other than the downstream side portion of the edge portion of the gas introduction port is directed from the outside to the inside of the intake pipe. An intake manifold for an internal combustion engine, wherein the intake manifold is inclined so as to expand.

The side view which shows the intake manifold of one Embodiment. Similarly front view. The side view which fractured | ruptured a part similarly. The front view which shows the gas introduction part which removed the gas introduction chamber housing. The longitudinal cross-sectional view which shows a gas introduction part. The front view which shows a part of manifold body. (A) is a front view which shows a gas inlet, (b), (c) is a front view which shows the gas inlet of other embodiment. The cross-sectional view which shows an intake pipe. The perspective view which shows the conventional intake manifold. The perspective view which shows the conventional intake manifold.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Intake manifold, 12 ... Intake pipe, 12a ... Pipe wall, 14 ... Manifold main body as member, 15 ... Similarly tank cover, 16 ... Also intake pipe housing, 17 ... Similarly gas introduction chamber housing, 18 ... As curved part DESCRIPTION OF SYMBOLS 1st curved part, 20 ... gas introduction chamber, 21 ... gas introduction port, 21a ... inclined surface, 21b ... inclined surface, 22 ... 2nd curved part as a curved part, 23 ... linear part, Eg ... internal combustion engine.

Claims (5)

In the intake manifold of the internal combustion engine in which a gas inlet for introducing blow-by gas is opened in each intake pipe,
An intake manifold for an internal combustion engine, wherein the gas introduction port is opened in a pipe wall of a portion facing a low speed region of the intake air flow in the intake pipe.   2. An intake manifold for an internal combustion engine according to claim 1, wherein a curved portion is formed in the intake pipe, and the gas introduction port is opened at a downstream portion on the inner corner side of the curved portion.   3. The internal combustion engine according to claim 2, wherein the intake pipe is formed with a curved portion that is curved in the same direction at two locations, and the gas introduction port is opened at a straight portion between the curved portions. Intake manifold.   The internal combustion engine according to any one of claims 1 to 3, wherein a gas introduction chamber for blow-by gas is formed outside a pipe wall of each intake pipe, and the gas introduction port is arranged in the gas introduction chamber. Intake manifold for engine.   The intake manifold for an internal combustion engine according to any one of claims 1 to 4, wherein the intake manifold is configured by combining members formed of synthetic resin.

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