JP2549547Y2 - Intake manifold for internal combustion engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake manifold for an internal combustion engine of a vehicle, and more particularly to a device for equally distributing an air-fuel mixture supplied from a fuel supply device to each branch port.

[0002]

2. Description of the Related Art When air passing through an air cleaner passes through a carburetor, it draws fuel to form an air-fuel mixture. When the air enters an engine body, an air-intake manifold passes through and distributes the air-fuel mixture to each cylinder. Things.

[0003] For example, as an intake manifold of a four-cylinder engine, a riser portion to which a fuel supply device such as a carburetor is connected, a curved portion extending from the riser portion, and four risers branched from the curved portion and communicating with each cylinder are provided. A so-called tournament type intake manifold having a branch port is well known.

[0004]

In the above-described conventional intake manifold of an engine, the fuel supply device is a carburetor, and when air passes through the carburetor, it induces fuel to form an air-fuel mixture and flow into each cylinder. Will be done.
For this reason, the amount of the air-fuel mixture into each cylinder may vary depending on the direction in which the air-fuel mixture flows. That is, in the case of a four-cylinder engine, the fuel distribution characteristics to each cylinder of the intake manifold are such that the outer cylinder becomes rich and the inner cylinder becomes lean during high-speed operation among engines in which inertia largely acts in the curved portion. Will be. On the other hand, during low-speed operation with small inertia, the outer cylinder tends to be lean and the inner cylinder tends to be rich, contrary to the above. Then
The air-fuel ratio supplied to each cylinder becomes uneven, which causes problems such as deterioration of engine stability, insufficient output, and increase in fuel consumption.

As a solution to such a problem, there is one disclosed in Japanese Utility Model Publication No. Sho 62-21738.
This is because, at the curved portion of the intake manifold, a streamline-shaped gutter is formed on the inner peripheral wall from the upstream to the downstream of the liquid fuel flow toward the center of the branch portion of the branch port, and the fuel distribution performance is achieved by the guiding action of the gutter. It is intended to improve the quality.

However, in this intake manifold, a gutter is formed on the inner peripheral side wall of the branch port.
It is effective during high speed operation in an engine in which inertia force largely acts, but there is a problem that good fuel distribution cannot be expected during low speed operation. Further, at this time, there is a problem that the fuel flows along the inner peripheral bottom wall of the branch port, adheres to the gutter and accumulates, causing incomplete combustion.

In order to solve such a problem of the present invention, an intake manifold for an internal combustion engine which has good distribution characteristics and prevents deterioration of engine stability, insufficient output, increased fuel consumption, etc. The purpose is to provide.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, an intake manifold for an internal combustion engine according to the present invention has a fuel supply device in which an adjacent riser section, a curved section extending from the riser section, and a branch from the curved section. In an intake manifold of an internal combustion engine having a plurality of branch ports communicating with each cylinder,
A rib provided on a bottom wall of the curved portion to distribute an air-fuel mixture supplied from the fuel supply device equally to the branch ports ,
The cross-sectional shape of the rib is formed in a substantially triangular chevron shape
At the same time, both hem parts are smoothly connected to the bottom wall, and
Te, the height of the ribs h, and width of the two skirt portions b, the indented
The height of the inner peripheral section of the curved portion is D, and the width of the inner peripheral section of the curved portion is
Is defined as B, the height h and the width b are formed in a shape having a relationship of D / 5 ≦ h ≦ D / 3 and B / 4 ≦ b ≦ B / 3. is there.

[0009]

[Effect] The supplied mixture is equally distributed to each branch port.
Form a guiding rib on the bottom wall of the curved part and identify this rib shape
The mixture is evenly distributed and supplied to each branch port along the ribs even when the engine is operating at a high speed or a low speed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a plan view of an intake manifold of an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line EE of FIG. 1, FIG. 3 is a sectional view taken along line FF of FIG. GG section, FIG. 5
6 shows a perspective view of the rib, FIG. 6 shows a graph showing the air-fuel ratio with respect to the height of the rib, and FIG. 7 shows a graph showing the air-fuel ratio with respect to the width of the rib.

As shown in FIG. 1, an intake manifold 11 of an internal combustion engine according to this embodiment has a riser portion 13 having a mounting seat 12 to which a carburetor (not shown) as a fuel supply device is attached, and a riser portion 13 not shown. Two curved portions 1 extending in the front-back (left-right in the drawing) direction of the engine body
, 4 and 15 and four branch ports 16, 17, 17, branching from the respective curved portions 14, 15 and communicating with the respective cylinders of the engine body.
18, 19 and the branch ports 16, 17, 18, 19
Cylinder head mounting part 20 formed integrally with the tip of the cylinder
It is composed of

The above-described intake manifold 11 for the internal combustion engine
In the first embodiment, the air-fuel mixture supplied from the carburetor is supplied to each of the branch ports 16, 1 on the inner bottom wall of each of the curved portions 14, 15.
Ribs 21 and 22 to be distributed evenly to 7, 18, and 19
Is formed. As shown in FIGS. 2 to 4, the rib 21 (22) has a triangular mountain shape in cross section, and one end on the riser portion 13 side is formed with an inclined surface 23, while the rib 21 (22) is formed on the branch port 16, 17 side. One end forms an acute angle (see FIG. 1).

Here, the optimum shape and the optimum formation position of the rib 21 (22) will be described. First, as shown in FIG. 4, the height of the inner circumference of the longitudinal section of the branch port 16 (or the curved portion 14) is D, the width is B, and as shown in FIG. Let A be the distance between the first and second branch portions 16 and 17 and C be the distance between the first and second branch portions of the branch ports 16 and 17. Also,
As shown in FIG. 5, the height of the rib 21 is h, the width is b, and the length is L. An experiment was conducted on the variation of the air-fuel ratio by changing the height h, the width b, and the length L of the rib 21.

The height h of the rib 21 is, as shown in FIG.
At the point a, the variation in the air-fuel ratio was the smallest. Therefore, it is considered that the height h of the rib 21 is optimal in the range described below. D / 5 ≦ h ≦ D / 3 Further, as shown in FIG. 7, it is considered that the width b of the rib 21 is optimal in the range shown below. B / 4 ≦ b ≦ B / 3 Further, as shown in FIG. 1, the length L of the rib 21 is considered to be optimal in the range shown below. C ≦ L ≦ A

Thus, the air that has passed through the air cleaner draws fuel when passing through the carburetor, becomes a mixture, and flows into the intake manifold 11. Then, the air-fuel mixture flows from the riser section 13 to the two curved sections 14 and 15,
Further, four branch ports 1 are provided from each of the curved portions 14 and 15.
It flows to 6, 17, 18, and 19 and enters the engine body.

At this time, since the ribs 21 and 22 having a triangular cross section are formed between the curved portions 14 and 15 and the branch ports 16, 17, 18, and 19, the engine can be operated at a low speed. Even when the mixture is ribs 21 and 22
Flows to the left and right along the branch ports 16, 17, 18,
19 is distributed and supplied.

[0018]

As described above in detail with reference to the embodiments, according to the hold between the intakes of the internal combustion engine of the present invention, the curved portion connecting the riser portion and the plurality of branch ports communicating with each cylinder. bottom wall fuel mixture supplied from the fuel supply device to form a rib for guiding and equally distributed to each branch port, the ribs
The cross-sectional shape of the
Both hem parts are connected smoothly to the bottom wall surface, and the height of the rib is h,
The width of both hem portions is b, the height of the inner peripheral cross section of the curved portion is D, and the curved portion
When the width of the inner peripheral cross section of B is B, the height h and the width b
Is formed in a shape having a relationship of D / 5 ≦ h ≦ D / 3 and B / 4 ≦ b ≦ B / 3.
The effective cross-sectional area of
The air-fuel mixture flows right and left along the ribs,
High-speed operation by allowing evenly distributed flow
To the outer cylinder during operation or to the inner cylinder during low speed operation.
It avoids bias and adhesion to ribs, obtains good distribution characteristics of air-fuel mixture, reduces air-fuel ratio variation, stabilizes the engine, prevents output shortage, increases fuel consumption, and reduces exhaust gas emissions. Cleaning efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of an intake manifold of an internal combustion engine according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along line EE of FIG.

FIG. 3 is a sectional view taken along line FF of FIG. 2;

FIG. 4 is a sectional view taken along line GG of FIG. 2;

FIG. 5 is a perspective view of a rib.

FIG. 6 is a graph showing an air-fuel ratio with respect to a height of a rib.

FIG. 7 is a graph showing an air-fuel ratio with respect to a width of a rib.

[Explanation of symbols]

 11 intake manifold 13 riser part 14,15 curved part 16,17,18,19 branch port 21,22 rib

Claims (1)

(57) [Scope of request for utility model registration] 1. An intake manifold for an internal combustion engine, comprising a riser portion adjacent to a fuel supply device, a curved portion extending from the riser portion, and a plurality of branch ports branching from the curved portion and communicating with the respective cylinders. A rib is provided on the bottom wall of the curved portion to distribute the mixture supplied from the fuel supply device equally to each of the branch ports, and the rib has a substantially triangular cross-sectional shape.
At the same time, both hem parts are smoothly connected to the bottom wall, and
Te, the height of the ribs h, and width of the two skirt portions b, the curved portion
D is the height of the inner circumferential cross section of B, and B is the width of the inner circumferential cross section of the curved portion.
Wherein the height h and the width b are formed in a shape having a relationship of D / 5 ≦ h ≦ D / 3 and B / 4 ≦ b ≦ B / 3. Manifold.