JPS6033330Y2 - intake manifold - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an intake manifold, and in particular is aimed at improving the uniform distribution of air-fuel mixture required for a tournament-type intake manifold.

In the intake manifold that connects the carburetor and each cylinder and sends the air-fuel mixture created by the carburetor to each cylinder, its inner diameter, length, shape, and inner surface finish have a large effect on engine performance. .

Further, the intake manifold is required to uniformly distribute the air-fuel mixture to each cylinder in the entire engine load range and to have high filling efficiency.

There are two types of intake manifolds, such as independent intake manifolds and tournament-type intake manifolds. Among these, the independent intake manifold is a type in which the manifold is branched for each cylinder directly from the vicinity of the carburetor intake, and its structure is similar to that of other manifolds. It becomes more complicated.

On the other hand, tournament-type intake manifolds have a relatively simple structure, are lightweight, and can be manufactured at low cost, so they are widely used in premixed spark ignition engines.

FIG. 1 shows an example of a conventional intake manifold called a tournament type manifold.

Here, 1 is an intake manifold, and in this example, a four-cylinder one is shown.

2 is a carburetor mounting seat, and a carburetor (not shown) is mounted on the carburetor mounting seat 2 via a gasket.

The manifold 1 has a riser part 3 connected to a straight pipe part to which the carburetor mounting seat 2 is attached, and is branched into two as a first branch pipe.
Further, each pipe is branched again at a branching portion 4 to form a second branch pipe.

Reference numeral 5 denotes a cylinder head mounting seat formed at the end of the pipe of the manifold 1 branched in this manner.

FIG. 2 shows a cross section near the branch 4 of the intake manifold 1. The first branch pipe 6 has a substantially circular shape, and a hot water passage 7 is attached to the lower surface side of the first branch pipe 6. This helps atomize the fuel within the tank.

However, in such a conventional tournament-type intake manifold, the inner surface of the manifold 1 from the riser portion 3 to the cylinder head mounting seat 5 is formed of a continuous smooth surface with a circular cross section, and the intake manifold is Due to the shape of the directional manifold, the intake air has a swirled flow.

Furthermore, the mainstream trend is as shown by the arrows in FIG.

That is, when the engine is running at low speeds, the flow tends to be as shown by the solid line, and when the engine is at high speeds, the flow tends to be as shown by the broken line.

Therefore, in a part-load operating range where sufficient fuel atomization occurs, the air-fuel mixture, or fuel, is evenly distributed to each cylinder regardless of this flow tendency, but the throttle valve of the carburetor is fully open. In a high-load operation region where a large amount of fuel is pumped, the fuel flows in the manifold 1 in the form of a liquid film, resulting in non-uniform distribution of fuel to each cylinder.

Furthermore, this phenomenon may or may not occur depending on the engine speed.

For this reason, there is a problem that the operating condition is not stable, leading to a decrease in output, and therefore fuel efficiency is also worsened.

In order to eliminate the above-mentioned drawbacks, the present invention has a protrusion along the flow of the air-fuel mixture on the inner wall of the hot water passage side of the first branch passage which is branched into at least two from the mounting seat of the carburetor. An intake manifold is provided with a partial wall to prevent the air-fuel mixture flowing into the manifold pipe from forming a spiral flow and causing uneven flow, and to evenly heat the air-fuel mixture and promote atomization. The purpose is to provide.

The present invention will be explained below based on the drawings.

In the following, parts similar to those in FIG. 1 are given the same reference numerals and their explanations will be omitted.

FIG. 3 shows an embodiment of the present invention, where 10 is a protruding wall.

In this example, the protruding wall 10 is made to protrude to the inner wall facing the carburetor mounting seat 2, and the protruding wall 10 is protruded from the riser part 3 where the manifold 1 branches into the first branch pipe 6, which is bifurcated.
The branch pipe 6 is made to protrude to the vicinity of the branch part 4 where it re-branches into the second branch pipe 6A.

Further, the height of the protruding wall 10 is such that it divides the lower half of the circular cross section of the branch pipe 6 into two, as shown in FIG.

FIG. 4 shows the cross-sectional shape of the first branch pipe 6 taken along the line BB in FIG. 3, where 11 is a hot water passage.

The hot water passage 11 uniformly heats the air-fuel mixture passing on both sides of the protruding wall 10 to promote atomization.

In the intake manifold 1 formed in this way, the first
By providing the protruding wall 10 in the branch pipe 6, the branch pipe 6 which has a swirling flow when there is no protruding wall 10 as in the conventional case.
Since the flow of the air-fuel mixture inside the cylinder is suppressed by the wall 10, the main flow of the air-fuel mixture flows evenly on both sides of the projecting wall 10 and reaches the branch part 4, and the intake air flow of each cylinder causes the main flow of the air-fuel mixture to flow through the second branch pipe 6A.
Flows evenly into each cylinder through.

FIG. 5 shows another embodiment of the present invention, in which 12
and 13 are protruding walls.

In this example, protruding walls are provided at two locations.

That is, similar to the example shown in FIG. 4, the protruding wall 12 is formed on the inner wall surface of the manifold 1 that faces the mounting seat 2; A wall 13 is provided, and no wall is provided in the center between the projecting walls 12 and 13, so that the pipes on both sides of these walls 12 and 13 are communicated.

Reference numeral 11 denotes a hot water channel that plays the same role as in the example described above.

Even with the intake manifold formed in this way, the same effects as in the above-mentioned example can be obtained.

As explained above, according to the present invention, a projecting wall is formed that extends from the inner wall of the first branch pipe of the manifold facing the carburetor mounting seat to the vicinity of the branch to each cylinder. The swirling flow of the air-fuel mixture generated in the intake manifold is suppressed.

For this reason, when the throttle valve is opened to a large degree and the engine is under high load, even if the fuel remains in the mixture in the form of a liquid film, the mixture is almost evenly divided along the protruding wall. The air-fuel mixture reaches the branch part and is evenly heated by the hot water passage provided on the back surface of the protruding wall, promoting atomization, so that the air-fuel mixture is evenly distributed to each cylinder in the entire rotation speed range.

Moreover, at partial load, the heating effect of the air-fuel mixture is enhanced by the heat conducted from the hot water passage to the protruding wall, so that the combustion efficiency is also improved with equal distribution to the cylinders.

In this way, the distribution of fuel to the cylinders can be improved over the entire engine speed range, resulting in increased output, reduced fuel consumption, and stable driving performance.

[Brief Description of the Drawings] Fig. 1 is a half-sectional view showing an example of the configuration of a conventional tournament-type intake manifold, Fig. 2 is a sectional view taken along line A-A, and Fig. 3 is a configuration of the intake manifold of the present invention. FIG. 4 is a sectional view taken along the line B--B, and FIG. 5 is a sectional view of the first branch pipe of the intake manifold showing another embodiment of the present invention. 1... Intake manifold, 2... Carburetor mounting seat, 3... Riser part, 4... Branch part, 5... Cylinder Head mounting seat, 6...
...First branch pipe, 6A...Second branch pipe, 7,1
1...Hot water passage, 10. 12. 13...
...protruding wall.

Claims (1)

[Scope of utility model registration request] A hot water passage is provided along a first branch pipe which branches into at least two from the vicinity of the mounting seat, and further includes at least two pipes from each of the first branch pipes.
In the intake manifold which branches a second branch pipe and distributes the air-fuel mixture generated in the carburetor to each cylinder via the first branch pipe and the second branch pipe, the hot water passage of the first branch pipe on each inner wall on the side to which the
At least one protruding wall is protruded along the direction in which the air-fuel mixture flows into the cylinder, and each of the hot water passages is in contact with an inner wall of the first branch pipe separated by the protruding wall. Absorption manifold.