JPS5830094Y2 - internal combustion engine intake port - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the intake port of a dual intake internal combustion engine.

For the purpose of improving combustion in internal combustion engines, mainly in the low load range, an intake port swirl generating means is installed to generate in-cylinder swirl in the intake air-fuel mixture, promoting atomization of the air-fuel mixture and disturbing flame propagation during combustion. It is known that the combustion rate can be increased by

However, this swirl generating means conversely causes an increase in intake resistance and a decrease in engine output in a region where the intake efficiency of the air-fuel mixture is important, such as in a high engine load region.

Therefore, we separated the intake system into two parts, supplying the mixture from only one swirl port when the engine was under low load, and supplying the mixture from the output port with less intake resistance when the engine was in a high load range. An intake method was considered.

In order to avoid complicating the structure of the intake system, there is a conventional intake port that opens and closes two ports at the same time with one intake valve, as shown in Figures 1 and 2. explain.

In the figure, 1 is the cylinder head and 2 is the combustion chamber.

3 indicates an intake valve, and 4 indicates an exhaust valve.

The intake port is separated into a primary port (swirl port) 5 and a secondary port (output port) 6, and these are located outside the secondary port 6 at the connection to the combustion chamber 2, with the primary port 5 being annular. It is separated by a partition wall γ.

The primary port 5 communicates only with the primary side of a carburetor (not shown), and the secondary port 6 similarly communicates only with the secondary side. Therefore, in the low engine load range, the air-fuel mixture is supplied exclusively from the primary port 15, Air-fuel mixture is supplied from both ports 5 and 6 only in the load range.

The port axis of the primary port 5 is unevenly distributed and curved from the bore center of the combustion chamber 2 to form a donut-shaped port outlet passage 5a.
The intake gas mixture is connected to the cylinder to give a twist to the intake air mixture flow to generate an in-cylinder swirl, that is, a counterclockwise swirling flow in the figure along the inner circumference of the cylinder.

On the other hand, the secondary port 6 is formed in a shape that has as little intake resistance as possible to increase intake efficiency.

As a result, in the low load range, the air-fuel mixture is supplied from the primary port 5 so as to generate swirling motion, which improves combustion and extends the lean limit and EGR limit of the air-fuel mixture to purify exhaust and improve fuel efficiency. In a high load range, as the secondary side of the carburetor operates, a large amount of air-fuel mixture also flows from the secondary port 6, increasing charging efficiency and preventing a drop in full-throttle output.

By the way, in the conventional primary port 5, a swirl S(
In the figure, clockwise; black arrow) occurs, and the main swirl S
o (counterclockwise in the figure; outlined arrow), acting in a counterclockwise manner to attenuate the in-cylinder swirl.

This is because the primary port 5 communicates with the donut-shaped port outlet passage 5a from diagonally above, so that the mixed air flow is divided into two flows along the annular surface.

For this reason, it was not possible to achieve a sufficient effect of the primary swirl, and the fuel efficiency and exhaust performance were not always satisfactory.

Therefore, as shown in Japanese Patent Publication No. 51-19094, it has been proposed to form a bump on the primary port to restrict the flow of air-fuel mixture from one direction and direct it to the other direction. There is.

However, if a bump is simply provided to limit the flow of the air-fuel mixture, the flow will not actively swirl by itself, and the center position of the opening area of the flow as the primary port will be offset. It only has the effect of creating a swirl by doing so.

Therefore, the entire opening area of the primary port is not used effectively, and especially on the side near the ridge of the annular opening, there is a shield in the form of a ridge that completely obstructs the flow in front of the flow, reducing the flow velocity. However, in an attempt to increase the suction flow rate without weakening the flow rate, the ridges provided to provide unidirectionality have the opposite disadvantage of weakening the flow rate.

In addition, simply providing a ridge that obstructs this flow will not work.
The rotational force of the intake air-fuel mixture itself in the primary port is not generated, and when viewed as a flux of the intake air flow, a bundle of straight streamlines is bent as a whole in the combustion chamber,
It is nothing more than what forms the swirl.

Therefore, the present invention not only restricts the flow of intake air and creates a simple swirl, but also provides a wing-shaped guide wall that itself creates a swirling flow.
To provide an intake port for an internal combustion engine that is configured so that the intake air flow itself swirls and generates a swirl, thereby generating a strong and uniform swirl.

Hereinafter, embodiments will be described based on the drawings.

In this invention, in order to swirl the intake air flow itself and generate a swirl in the whole, as shown in FIGS. 3 to 5,
At the connection between the primary port 5 and the donut-shaped port outlet passage 5a, a wing-shaped guide wall 10 that is inclined from the lower surface of the connection port in the direction of the swirl flow and that itself generates a swirl flow is connected to the annular partition T and the inner wall 11 of the outlet passage. Formed as a partition between the

In other words, the air-fuel mixture flowing into the donut-shaped outlet passage 5a,
The guide wall 10 causes the combustion chamber to swirl in only one direction, eliminates the intake air that goes around in the opposite direction, and unifies the swirl generated in the combustion chamber 2 into the same swirl flow.

As a result, when the air-fuel mixture flows from the primary port 5 into the doughnut-shaped port outlet passage 5a, no separation of the air-fuel mixture occurs, and all the air-fuel mixture is sucked into the combustion chamber 2 while swirling in the same direction.

Therefore, the swirl is not canceled out by opposing forces, and a strong inertial force is imparted, contributing to combustion improvement with sufficient sustainability even if it is lost from the compression stroke to the early stage of the combustion stroke.

In addition, the velocity component in the piston operating direction is particularly strong at the connection part from the primary port 5 to the port outlet path 5a, but since the guide wall 10 is provided here to guide the velocity component in the horizontal direction to increase, Effective for strengthening swirl.

Incidentally, if the lower end of the guide wall 10 is extended to the vicinity where it comes into contact with the back surface of the umbrella portion of the intake valve 3, the guiding effect will be increased accordingly.

As in the embodiments of FIGS. 6 and 7, a plurality of guide walls 10a
, 10b in symmetrical positions with respect to each other, the swirl directionality and the swirl damping prevention effect are further improved.
An even stronger cylinder swirl can be obtained.

As described above, according to the present invention, the guide wall 10 is provided at the connection portion from the primary port 5 to the port outlet passage 5a to generate a spiral swirling flow.
A powerful swirl can be generated in the low load range, and the in-cylinder swirl can be maintained even during the compression stroke and early combustion stage.
Combustion can be further improved.

Since the swirl can be strengthened in this way, it is also possible to omit twisting of ports, etc., which were conventionally required, and there is also the effect of improving productivity.

In addition, in the engine high load range, the air-fuel mixture is also supplied from the secondary port 6, and the effect of filling the air-fuel mixture in the cylinder is improved, which is exactly the same as in Figs. 1 and 2.
Identical parts are given the same reference numerals and explanations will be omitted.

[Brief explanation of drawings]

Fig. 1 is a plan view of a conventional device, Fig. 2 is a sectional view, Fig. 3 is a plan view showing an embodiment of the present invention, Fig. 4 is a sectional view, and Fig. 5 is a cross section taken along the line I-I in Fig. 4. FIG. 6 is a cross-sectional view of another embodiment, and FIG. 1 is a cross-sectional view thereof taken along the line ■-■. 1... Cylinder head, 2... Combustion chamber, 3... Intake valve, 5... Primary port, 5a... Port outlet path , 6...
Secondary port, 7... Annular bulkhead, 10...
...Guidance wall, 10...Guidance wall, 11...
...The inner wall of the exit route.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A primary port that supplies intake air to create cylinder swirl in the low and medium load range of the engine, and a port for output in the high load range.
An internal combustion engine having a secondary port that supplies intake air to the combustion chamber, a primary port formed in an annular shape around the outer periphery of the secondary port via a partition wall at the connection to the combustion chamber, and both ports opened and closed by the same intake valve. An intake port for an internal combustion engine, wherein a wing-shaped guide wall is provided in a communication path between a primary port and an annular port outlet passage to direct a port swirl flow in only one direction and to generate a swirl flow itself. 2. An intake port for an internal combustion engine according to claim 1, wherein the guide wall has a plurality of stages in the annular port outlet passage. 3. The intake port for an internal combustion engine according to claim 1, wherein the guide wall is inclined in the same direction as the port swirl flow.