JP3205504B2 - Intake manifold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an intake manifold for an engine, and more particularly to an intake manifold for an engine to which a side draft carburetor is applied.

[0002]

2. Description of the Related Art An intake manifold in an engine to which a carburetor is applied is required to have a function of uniformly supplying an air-fuel mixture to each cylinder of the engine and a function of uniformly distributing liquid fuel flowing along an inner wall surface. Accordingly, the present applicant has disclosed Japanese Utility Model Laid-Open No. 2-144654 and Japanese Utility Model Laid-Open No.
No. 60 proposes an intake manifold as shown in FIG. In FIG. 3, first open ribs 24 project outward on both sides of the inner wall 23 of the first branch portion 22 facing the gathering portion 21 to provide a pool space 25 and head toward the first branch portion 22. Collecting part 21
The second vertical ribs 26 protrude on both sides of the outlet of the cylinder, and the branch passages branched at the first branch portion 22 are branched at the second branch portions 27, respectively, to form four branch passages corresponding to the respective cylinders. 28
Is formed. 29 is a throttle valve, 30 is a carburetor, and 31 is its main nozzle.

According to such a configuration, when the fuel adhering to the inner wall surface of the collecting portion 21 is conveyed to its outlet, the fuel scatters at the tip of the second vertical rib 26 and mixes into the intake air, thereby uniformly. Even when the mixture is distributed and the flow rate of the mixture increases in a high load region, the mixture is diffused in the pool space 25, so that the mixture can be surely prevented from being concentrated in the branch passage 28 near the collecting portion 21, and Liquid fuel adhering to 23 is also scattered at the tips of the first vertical ribs 24 on both sides and is evenly distributed. Thus, even if the pipe length is shortened, the mixture and the liquid fuel can be evenly distributed.

[0004]

By the way, in an engine to which a carburetor is applied, an air-fuel ratio is enriched by reducing the amount of air by a choke system during a warm-up operation from a start at a low temperature. Poor fuel distribution between cylinders can easily lead to poor starting and engine malfunction. In particular, at low temperatures, the fuel is poorly atomized and flows in a liquid state. If the fuel flowing in the liquid state is poorly distributed, poor starting or engine malfunction will result.

However, in the intake manifold having the structure shown in FIG. 3, when the fuel flows in a liquid state because the amount of air flowing during the warm-up operation at a low temperature is small, the first
Even if the vertical ribs 24 are protruded, fuel supply is concentrated in the branch passages 28 adjacent to both sides of the air pocket space 25, and there is a problem that the engine malfunctions.

On the other hand, in order to collect the fuel flowing out of the main nozzle of the carburetor into the collecting portion and surely distribute the fuel uniformly, as shown in FIG.
It is conceivable to apply a tournament-type intake manifold that branches the branch passage 2 and branches the branch passages 33 from the branch passages 32 to the left and right, respectively. For,
There is a problem that it cannot be applied when there is a space restriction. Further, as shown in FIG. 5, a down-draft carburetor 40 is applied, and an air-fuel mixture is introduced from above into a collecting portion 42 of an intake manifold 41 disposed at a lower portion thereof.
It is conceivable that the air-fuel mixture is once accumulated in the collecting portion 42 and then distributed to the respective branch passages 43 so that the air-fuel mixture is equally distributed. There is a problem that there are many.

Incidentally, Japanese Utility Model Application Laid-Open No. 55-23458, Japanese Utility Model Application Laid-Open No. 58-152561, Japanese Utility Model Application Laid-Open No. 60-1719.
No. 54 discloses an intake manifold in which ridges or ribs are protruded from the bottom surface of a branch portion. Does not eliminate the problem.

The present invention has been made in consideration of the above-mentioned conventional problems, and is capable of uniformly distributing fuel to each cylinder from a low-temperature start to a warm-up operation, so that there is no danger of starting failure or engine malfunction and compact. It is intended to provide a simple intake manifold.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to an intake manifold mounted on an engine in a substantially horizontal position and connected to a side draft carburetor horizontally.
In the intake manifold, in which a plurality of branch passages corresponding to each cylinder are formed by sequentially branching left and right from the collecting portion,
Vertical ribs protrude outwardly on both sides of the inner wall facing the gathering portion in the first branch portion, and the portion of the outlet of the gathering portion located on the main nozzle side of the carburetor and the inner wall facing the gathering portion A second bottom rib having an appropriate height from the bottom is protruded between the bottom and the liquid fuel flowing out of the main nozzle flows along the bottom toward the main nozzle side, and is concentrated and distributed to the branch passage on the main nozzle side. This is prevented by the second bottom rib, so that the fuel is evenly distributed to all the branch passages.

[0010]

[0011]

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

In FIG. 1, reference numeral 1 denotes an intake manifold which is mounted on a four-cylinder engine of an automobile in a substantially horizontal posture.
A pair of left and right second-stage branch portions 4 is provided on both sides of the first-stage branch portion 3 to branch into four branch passages 5 corresponding to four cylinders. In the first branching portion 3, a pair of first opening portions is formed on both sides of the inner wall 6 facing the collecting portion 2 so as to open outward.
The vertical ribs (vertical ribs in claims 1 and 2) are projected, and a pool space 8 is formed in front of the inner wall 6 and the first vertical ribs 7 on both sides thereof. In addition, second vertical ribs 9 are protrudingly provided on both sides of the outlet of the collecting section 2.

Reference numeral 10 denotes a throttle body connected to the inlet of the collecting portion 2 of the intake manifold 1, reference numeral 11 denotes a throttle valve, reference numeral 12 denotes a carburetor, and reference numeral 13 denotes a main nozzle thereof.

The first vertical rib 7 is provided on both sides of the first vertical rib 7 with a first height of about several mm and protruding from the bottom surface 1a over substantially half the entire width of the second-stage branch portion 4. Bottom rib. Further, 15 is an appropriate distance of about several mm from the bottom surface 1a between the second vertical rib 9 located on the main nozzle 13 side of the inner carburetor 12 of the second vertical rib 9 and the inner wall 6 facing the collecting portion 1. It is the 2nd bottom rib projected in height. In FIG. 1, reference numeral 20 denotes a water jacket for promoting the atomization of the air-fuel mixture at a low temperature.

Next, the operation of the intake manifold 1 having the above configuration will be described. The air-fuel mixture flowing into the intake manifold 1 flows from the collecting portion 2 to the inner wall 6 of the first-stage branch portion 3.
, And the direction is changed at the air pocket portion 8, and is surely dispersed in the bent passage formed by the first vertical rib 7 and the second vertical rib 9. At 4, it is equally distributed to each branch passage 5. Therefore, even when the flow rate of the air-fuel mixture increases in the high load region, the air-fuel mixture is reliably diffused in the air pocket space 8 as described above, so that the air-fuel mixture is surely concentrated in the branch passage 5 close to the collecting part 2. Can be suppressed.

Further, the fuel adhering to the inner wall surface of the collecting section 2 is scattered at the tip of the second vertical rib 9 when being carried to the outlet of the collecting section 2 and is mixed into the intake air. 5 equally distributed. In addition, the inner wall 6
The liquid fuel that has adhered to the first vertical ribs 7 on both sides is also scattered and evenly distributed. Therefore, even if the pipe length is shortened, the air-fuel mixture and the liquid fuel can be evenly distributed.

Further, the liquid fuel flowing along the bottom surface 1a during the warm-up operation from the low temperature start is supplied to the first bottom ribs 14a.
As a result, the fuel is distributed to the branch passages 5 and 5 on both sides at the substantially central portion of the second-stage branch portion 4, so that the fuel is evenly distributed to all the branch passages 5. Further, when the liquid fuel flowing out from the main nozzle 13 flows along the bottom surface 1a, it tends to flow toward the main nozzle 13 side. However, since the second bottom rib 15 is provided, the fuel flows into the first stage. The liquid fuel collected at the center of the branch portion 3 and flowing along the bottom surface 1a can be evenly distributed to all the branch passages 5.

Thus, according to the present embodiment, the distribution of the liquid fuel at the time of choking can be improved, and the occurrence of poor starting and engine malfunction can be reliably prevented.

[0019]

According to the intake manifold of the present invention, the second bottom surface having an appropriate height from the bottom surface is located between the portion of the outlet of the collecting portion located on the main nozzle side of the carburetor and the inner wall facing the collecting portion. Since the ribs protrude, the liquid fuel flowing out of the main nozzle flows to the main nozzle side along the bottom surface and is concentrated and distributed to the branch passage on the main nozzle side. This can be prevented by the ribs, and the fuel can be evenly distributed to all the branch passages.

[0020]

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view of an intake manifold according to an embodiment of the present invention.

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

FIG. 3 is a cross-sectional plan view of a conventional intake manifold.

FIG. 4 is a cross-sectional plan view of a conventional tournament-type intake manifold.

FIG. 5 is a perspective view of an intake manifold combined with a conventional down-draft type carburetor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intake manifold 1a Bottom surface 2 Assembling part 3 First stage branch part 4 Second stage branch part 5 Branch passage 6 Inner wall 7 First vertical rib (vertical rib) 9 Second vertical rib 12 Carburetor 13 Main nozzle 14 First Bottom rib 15 Second bottom rib

Claims (2)

(57) [Claims] When the engine is mounted in a substantially horizontal posture,
An intake manifold in which side draft carburetors are horizontally connected to each other, and the intake manifold in which a plurality of branch passages corresponding to each cylinder are formed by sequentially branching left and right from a gathering portion. Vertical ribs protrude outwardly on both sides of the inner wall facing the gathering part,
And at the outlet of the collecting part, on the main nozzle side of the carburetor.
From the bottom between the place where it is placed and the inner wall facing the
An intake manifold characterized by projecting a second bottom rib of this height . 2. Appropriate height from the bottom surface following each vertical rib
Protrude the first bottom rib into the area approximately half the full width of the next branch.
The intake manifold according to claim 1, wherein the intake manifold is provided.