JPH0223691B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake port for an internal combustion engine in which an intake hole is opened at a position eccentric from the center of an end face of a cylinder chamber, an intake valve is provided in the intake hole, and an intake passage is connected to the intake port.

As disclosed in Japanese Unexamined Patent Publication No. 59-180027, the present inventor has previously developed an intake passage in this type of intake port for the purpose of generating a moderately stable vortex flow without reducing the volumetric efficiency. consists of a vortex generating part at the end of the passage that communicates with the intake hole and surrounds the intake valve, and an introduction part other than the end of the passage, and between the peripheral surface of the valve shaft of the intake valve and the peripheral surface of the vortex generating part facing it The width is made wider at the outer part on the cylinder chamber circumferential side than the inner part on the center side of the cylinder chamber, and the introduction part is connected to the wide outer part of the vortex generating part, and the vortex generating part facing the opening surface of the intake hole is made wider. The height between the ceilings of the parts is reduced from the wide outer part to the narrow inner part around the valve stem, and the average reduction is equal to 0 of the diameter of the intake hole per degree around the valve stem. Invented an intake port for internal combustion engines that is set to 0.18% or more. Although this invention can achieve its purpose, it cannot be said that it can generate a strong vortex flow with high volumetric efficiency.

The purpose of the present invention is to improve the above-mentioned previous invention,
An object of the present invention is to provide an intake port for an internal combustion engine that can generate a strong vortex flow with high volumetric efficiency.

In order to achieve the above object, the present invention limits various parts of the above conventional invention based on the results of experiments.

That is, the present invention has the above-mentioned conventional invention,
The circumferential surface of the outer part of the turbulent flow generating part is formed into a cylindrical surface, and the central axis of this cylindrical surface is eccentric from the central axis of the intake hole toward the circumferential surface of the outer part of the vortex generating part. is set to 2% or more of the intake hole diameter and 50% or less,
The inlet is formed into a substantially straight line, and the connection angle between the outer part of the vortex generating part and the inlet is set so that the main flow of intake air from the inlet to the outer part of the vortex generating part is around the outer part and around the valve shaft. This is an intake port for an internal combustion engine, characterized in that the intake port is set at an angle that allows air to flow between the surfaces.

In addition, for this intake port, the distance from the center axis of the intake hole to the center line of the introduction part is the diameter of the intake hole.
It is characterized by setting the introduction part to be 20% or more and 60% or less, and the minimum width of the introduction part is set to be 25% or more and 85% or less of the diameter of the intake hole by forming the introduction part in a tapered shape. It is characterized by the fact that

As is clear from the experimental results described later, the intake port of the present invention can generate a strong vortex flow with high volumetric efficiency.

Next, examples of the present invention will be described.

The intake ports of the internal combustion engine in this example are shown in Figures 1 and 2.
As shown in the figure, a circular intake hole 12 is opened in the circular end face of the cylinder chamber 11 at a position eccentric from the center to the peripheral side, and an intake valve 13 of a poppet valve is provided in the intake hole 12, and an intake passage 15 is provided. The intake passage 15 is composed of a vortex generation part 16 at the end of the passage that communicates with the intake hole 12 and surrounds the intake valve 13, and an introduction part 19 at the other end of the passage, and the peripheral surface of the vortex generation part 16 is connected to the intake valve 13. The cylinder chamber 11 is formed by smoothly connecting two cylindrical surfaces facing the circumferential surface of the valve stem 14 , and the width between the circumferential surface of the valve stem 14 and the circumferential surface of the vortex generating portion 16 facing the cylinder chamber 11 is The outer portion 17 on the circumferential side is wider than the inner portion 18 on the center side of the cylinder chamber, and the valve shaft 14
The introduction part 19 is connected to the wide outer part 17 of the vortex generating part 16 along the tangential direction, and the introduction part 19 is connected to the opening surface of the intake hole 12. The height between the ceilings of the vortex generating part 16 facing this is kept the same or gradually decreased from the wide outer part 17 to the narrow inner part 18 around the valve shaft 14, and the amount of decrease is 0.18% of the intake hole diameter d per degree around the valve stem 14
It is set within Further, the center axis of the cylindrical surface constituting the circumferential surface of the inner portion 18 of the vortex generating portion is aligned with the center axis of the intake hole 12, while the outer portion 17
The central axis of the cylindrical surface constituting the peripheral surface of the air intake hole 12 is eccentric from the central axis of the intake hole 12 toward the peripheral surface of the outer portion, and the eccentricity e is 2% or more and 50% or less of the diameter d of the air intake hole 12. , the introduction part 19 is formed into a substantially straight line, and the connection angle between the outer part 17 and the introduction part 19 is set to the introduction part 1.
The angle is set such that the main flow of intake air from 9 to the outer portion 17 flows between the circumferential surface of the outer portion and the circumferential surface of the valve shaft 14. Furthermore, the distance l from the center axis of the intake hole 12 to the center line of the introduction part 19 is 20 of the diameter d of the intake hole.
% or more and 60% or less, and the introduction part 19 having a rectangular cross section is formed into a tapered shape to increase the minimum width w of the introduction part.
is set to be 25% or more and 85% or less of the diameter d of the intake hole 12.

In this intake port, the intake air flowing through the intake passage 15 flows from the introduction part 19 into the vortex generating part 16 and flows into the cylinder chamber 11 via the intake hole 12. from the center position of the outer part 17 of the vortex generating part to the valve shaft 1
4, flows into the cylinder chamber 11 through the intake hole 12 along the tangential direction of the portion of the circumference adjacent to the intake hole, and is circulated along the circumferential surface of the cylinder chamber 11. It becomes a vortex. A strong eddy current is generated under high volumetric efficiency.

Experiment 1 In the intake port of the above embodiment, the amount e that the central axis of the cylindrical surface constituting the peripheral surface of the outer portion 17 of the vortex generating portion is eccentric from the central axis of the intake hole 12 toward the peripheral surface of the outer portion 17 was set to various values for the diameter d of the intake hole 12, and the strength of the vortex generated in the cylinder chamber 11, that is, the swirl ratio SR, and the pressure loss ΔP of the intake passage 15 were determined for each value. , the results shown by the solid line in the diagram of FIG. 3 were obtained. As is clear from the upper and lower halves of the diagram, when the dimensionless eccentricity e/d is greater than 0.5,
As the swirl ratio SR becomes smaller, the pressure loss ΔP becomes larger. On the other hand, as the dimensionless eccentricity e/d becomes smaller than 0.1, the swirl ratio SR decreases and the pressure loss ΔP increases.
When d becomes smaller than 0.02, the amount of decrease in swirl ratio SR and the amount of increase in pressure loss ΔP become large. Therefore, when the dimensionless eccentricity e/d is 0.02 or more and 0.5 or less, the swirl ratio SR is large and the pressure loss ΔP is small. That is, a strong vortex flow occurs under high volumetric efficiency. In addition, when the dimensionless eccentricity e/d is 0.03 or more,
Even better performance can be obtained when it is less than 0.3.

Note that the connection angle between the outer portion 17 and the introduction portion 19 is set to an angle other than the angle at which the main flow of intake air from the introduction portion 19 to the outer portion 17 flows between the periphery of the outer portion and the circumferential surface of the valve shaft 14. In this case, as shown by the broken line in the diagram of Fig. 3, the dimensionless eccentricity e/d is
Performance deteriorates in the region smaller than 0.1,
As the swirl ratio SR suddenly decreases, the pressure loss ΔP increases.

In addition, the connection angle α between the outer part 17 and the introduction part 19 was set to various values, and the swirl ratio SR and pressure loss ΔP were determined for each value, as shown in the diagram in Figure 4. I got good results.

However, for convenience, the above connection angle α is set between the circumferential surface of the inner portion 18 and the introduction portion 19 as shown in FIG.
A connection line between the inner surface of the
To the connecting surface that includes the intersection line between the surface rotated 60 degrees toward the outer part 17 with the center axis of the intake hole as the center axis and the peripheral surface of the outer part 17 or the outer surface of the introduction part 19. This is the angle formed by the center line of the introduction part 19.

As is clear from the upper and lower halves of the diagram in FIG. 4, when the connection angle α becomes larger than 135 degrees, the swirl ratio SR becomes very small and the pressure loss ΔP becomes large. That is, the main flow of the intake air flowing from the introduction part 19 into the vortex generating part 16 comes to collide with the valve shaft 14, and the vortex becomes weaker. Therefore, when the connection angle α is 135 degrees or less, the swirl ratio PR is large and the pressure loss ΔP is small. In addition, the connection angle α
Even better performance is obtained when the temperature is below 110 degrees.
On the other hand, when the contact angle α becomes smaller than 15 degrees, the swirl ratio SR suddenly decreases and the pressure loss ΔP increases. That is, a part of the main flow of the intake air flowing from the introduction part 19 into the outer part 17 of the vortex generating part collides with the circumferential surface of the outer part, and the vortex becomes weaker.

Therefore, if the connection angle α is set to an angle at which the main flow of intake air from the introduction part 19 to the outer portion 17 flows between the circumferential surface of the outer portion and the circumferential surface of the valve shaft 14, the swirl ratio SR will be large and the pressure will increase. Loss ΔP becomes smaller.

Experiment 2 In the intake port of the above example, intake hole 1
Distance l from the center axis of 2 to the center line of the introduction part 19
was set to various values for the diameter d of the intake hole 12, and the swirl ratio SR and pressure loss ΔP were determined for each value, and the results were obtained as shown in the diagram in Figure 5. . As is clear from the upper and lower halves of the diagram, when the dimensionless distance l/d is larger than 0.6 and smaller than 0.2,
As the swirl ratio SR becomes smaller, the pressure loss ΔP becomes larger. Therefore, when the dimensionless distance l/d is 0.2 or more and 0.6 or less, the swirl ratio SR is large and the pressure loss ΔP is small.

Moreover, the minimum width w of the introduction part 19 formed in a tapered shape
was set to various values for the diameter d of the intake hole 12, and the swirl ratio SR and pressure loss ΔP were determined for each value, and the results shown in the diagram in Figure 6 were obtained. . As is clear from the upper and lower halves of the diagram, the dimensionless minimum width w/d is 0.85
When it becomes larger, or when it becomes smaller than 0.25, the swirl ratio SR becomes smaller and the pressure loss ΔP becomes larger. Therefore, the dimensionless minimum width w/d
When is 0.25 or more and 0.85 or less, the swirl ratio SR is large and the pressure loss ΔP is small.

[Brief explanation of drawings]

FIG. 1 is a plan view of an intake port according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line -- in FIG. A diagram showing the relationship between the core amount e/d, and Figure 4 shows the swirl ratio at the same intake port.
A diagram showing the relationship between SR, pressure loss ΔP and connection angle α, and Figure 5 shows the swirl ratio at the same intake port.
Figure 6 is a diagram showing the relationship between SR, pressure loss ΔP and dimensionless distance l/d, and Figure 6 is a diagram showing the relationship between swirl ratio SR, pressure loss ΔP and dimensionless minimum width w/d at the same intake port. . 11: Cylinder chamber, 12: Intake hole, 13: Intake valve, 14: Valve shaft, 15: Intake passage, 16: Whirlpool generating part, 17: Outside part, 18: Inside part, 19:
Introduction.

Claims (1)

[Scope of Claims] 1. In an intake port of an internal combustion engine in which an intake hole is opened in an end face of a cylinder chamber at a position eccentric from the center thereof, an intake valve is provided in the intake hole, and the intake passage is connected to the intake port, the intake passage is connected to the intake port. Consisting of a vortex-generating part at the end of the passage that communicates with the intake hole and surrounds the intake valve, and an introduction part other than the end of the passage, the width between the circumferential surface of the valve shaft of the intake valve and the circumferential surface of the vortex-generating part facing it. The outer part on the circumferential side of the cylinder chamber is wider than the inner part on the center side of the cylinder chamber, and the introduction section is connected to the wide outer part of the vortex generating part, so that the opening surface of the intake hole and the vortex generating part facing this are made wider. The height between the ceilings of the valve is reduced from the wide outer part to the narrow inner part around the valve stem, and the average reduction is 0% of the diameter of the intake hole per degree around the valve stem.
With the above settings set to 0.18% or less, the circumferential surface of the outer part of the vortex generating part is formed into a cylindrical surface, and the central axis of this cylindrical surface is moved from the central axis of the intake hole to the circumferential surface of the outer part of the vortex generating part. The eccentricity is set to 2% or more and 50% or less of the diameter of the intake hole, the introduction part is formed almost straight, and the connection angle between the outer part of the vortex generating part and the introduction part is set to An intake port for an internal combustion engine, characterized in that the main flow of intake air from the introduction part to the outer part of the vortex generating part is set at an angle such that it flows between the circumferential surface of the outer part and the circumferential surface of the valve shaft. 2. An intake port for an internal combustion engine according to claim 1, wherein the distance from the center axis of the intake hole to the center line of the introduction part is set to 20% or more and 60% or less of the diameter of the intake hole. . 3. The internal combustion engine according to claim 1 or 2, wherein the introduction part is tapered and the minimum width of the introduction part is set to 25% or more and 85% or less of the diameter of the intake hole. Engine intake port.