JPH0520564B2 - - 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 the same or decreases from the wide outer part to the narrow inner part around the valve stem, and the average decrease is equal to the height of the intake hole per degree around the valve stem. Invented an internal combustion engine intake port that is set within 0.18% of the diameter.

Although this conventional intake port can generate a moderately stable vortex without reducing volumetric efficiency, it cannot be said that the swirl ratio of the vortex generated is sufficiently high.

An object of the present invention is to solve the conventional problems as described above.

The present invention provides an intake port for an internal combustion engine in which an intake hole is opened at a position eccentric from the center of the end face of a cylinder chamber, an intake valve is provided in the intake hole, and the intake passage is connected to the intake port. It is composed of a vortex generation part at the end of the passage that communicates with the intake valve and an introduction part other than the end of the passage, and the circumferential surface of the vortex generation part is formed into a substantially cylindrical surface facing the circumference of the valve shaft of the intake valve. , the width between the circumferential surface of the valve shaft of the intake valve and the circumferential surface of the vortex generating portion facing the same is made wider at the outer part on the cylinder chamber circumferential side than in the inner part on the cylinder chamber center side,
It gradually narrows from the outer part to the inner part around the valve stem, and the circumferential surface of the outer part of the vortex generating part is arranged almost along the circumferential surface of the cylinder chamber, and the outer part of the vortex generating part is wide. Connect the almost linear introduction part along the tangential direction, and adjust the height between the opening surface of the intake hole and the ceiling of the vortex generation part facing this by connecting the wide outer part to the narrow part around the valve stem. It is the same or decreases while reaching the inner part, and the average decrease amount is set within 0.18% of the diameter of the intake hole per degree around the valve stem, and the center of the end face of the cylinder chamber and the center of the intake hole are connected. The angle that the line makes with the line connecting the centers of the end faces of multiple cylinder chambers arranged in series is set within 70 degrees, so that the main flow of the intake air flowing through the intake passage is directed from the introduction part to the outer part of the vortex generation part. Flows between the circumferential surface and the circumferential surface of the valve shaft of the intake valve, passes through the intake hole, and flows into the cylinder chamber along the tangential direction of the portion of the circumferential surface adjacent to the intake hole,
This is an intake port for an internal combustion engine, characterized by having a configuration in which a vortex flow swirls along the circumferential surface of a cylinder chamber.

In the intake port of the internal combustion engine of the present invention, the main flow of the intake air flowing through the intake passage flows from the introduction part between the peripheral surface of the outer part of the vortex generating part and the peripheral surface of the valve shaft of the intake valve, and flows through the intake hole. The fluid then flows into the cylinder chamber along the tangential direction of the portion of the circumferential surface of the cylinder chamber adjacent to the intake hole, forming a vortex flow that swirls along the circumferential surface of the cylinder chamber.

As is clear from the experimental results described later, in the intake port of the internal combustion engine of the present invention, a vortex flow with a higher swirl ratio can be generated without reducing the volumetric efficiency compared to the conventional intake port.

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. Two cylindrical surfaces facing the circumferential surface of the valve stem 14 are smoothly connected to form a substantially cylindrical surface, and the width between the circumferential surface of the valve stem 14 and the circumferential surface of the vortex generating portion 16 facing this is determined. , the outer part 1 on the circumferential side of the cylinder chamber 11
7, it is wider than the inner part 18 on the center side of the cylinder chamber, and gradually narrows from the outer part 17 to the inner part 18 around the valve shaft 14, so that the circumferential surface of the outer part 17 is the same as the circumferential surface of the cylinder chamber 11. A substantially straight introduction part 19 is connected to the wide outer part 17 of the vortex generating part 16 along the tangential direction thereof, and the vortex generating part 16 facing the opening surface of the intake hole 12 is connected to the wide outer part 17 of the vortex generating part 16. The height between the ceilings is the same or gradually decreases around the valve stem 14 from the wide outer part 17 to the narrow inner part 18, and the amount of decrease is made once around the valve stem 14. 0.18% of the intake hole diameter d
As shown in FIG. 3, the line connecting the center of the intake hole 12 and the center of the end surface of the cylinder chamber 11 is set within The angle θ with respect to the line connecting the centers is set within 70 degrees, specifically 6 degrees, and as shown in FIG. The distance r is set within a percentage of the diameter D of the cylinder chamber 11, specifically, 25%.

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 axial center position to the peripheral surface of the outer portion 17 of the vortex generating portion
4, flows into the cylinder chamber 11 through the intake hole 12 along the tangential direction of the portion of the circumference near the intake hole, and swirls along the circumferential surface of the cylinder chamber 11. becomes.

In the intake port of this example, each value is the angle θ that a line connecting the center of the intake hole 12 and the center of the end surface of the cylinder chamber 11 makes with a line connecting the centers of the end surfaces of a plurality of cylinder chambers 11 arranged in series. and for each value, the strength of the vortex generated in the cylinder chamber 11, that is, the swirl ratio SR and the cylinder chamber 11.
When we calculated the volumetric efficiency VE, we obtained experimental results as shown in the diagram in Figure 4. In addition, in the same diagram, the sign of the above arrangement angle θ is the same as that of the intake hole 1.
The center of 2 is a cylinder chamber 1 in which a plurality of cylinder chambers are arranged in series.
1 is positive when it is located on the introduction part 19 side of the intake passage with respect to the line connecting the centers of the end faces of
It is considered negative when it is located on the opposite side.
As is clear from the top of the diagram, the swirl ratio
SR decreases rapidly when the arrangement angle θ exceeds 70 degrees, and reaches a very high value within 45 degrees. As is clear from the bottom of the diagram, the volumetric efficiency VE is
It does not change greatly depending on the size of the arrangement angle θ. Therefore, if the arrangement angle θ is set within 70 degrees, the swirl ratio can be increased without reducing the volumetric efficiency, and if the arrangement angle θ is set within 45 degrees, the swirl ratio can be increased without reducing the volumetric efficiency. The ratio can be very high.

Further, in the intake port of this example, the intake hole 12
The distance r between the center of and the center of the end face of the cylinder chamber 11
is set to each value for the diameter D of the cylinder chamber 11,
Swirl ratio SR for each value r/D
When we calculated the volumetric efficiency VE, we obtained experimental results as shown in the diagram in Figure 5. As is clear from the upper part of the diagram, the swirl ratio SR decreases rapidly when the above value, that is, the dimensionless arrangement distance r/D exceeds 0.3, and becomes a very high value when it is 0.15 or more and 0.26 or less. . As is clear from the lower part of the diagram, the volumetric efficiency VE does not change significantly depending on the dimensionless arrangement distance r/D. Therefore, if the dimensionless arrangement distance r/D is set within 30%, the swirl ratio can be increased without reducing the volumetric efficiency.
When the dimensionless arrangement distance r/D is set to 15% or more and 26% or less, the swirl ratio can be made very high without reducing the volumetric efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of an intake port according to an embodiment of the present invention, FIG. 2 is a plan view of the intake port, and FIG. 3 is a schematic plan view showing the arrangement of the intake ports. Figure 4 is a diagram showing the relationship between the intake hole arrangement angle and swirl ratio or volumetric efficiency at the same intake port, and Figure 5 is a diagram showing the relationship between the intake hole arrangement distance and the swirl ratio or volumetric efficiency at the same intake port. It is. 11...Cylinder chamber, 12...Intake hole, 13...
...Intake valve, 14...Valve stem, 15...Intake passage, 1
6... Vortex generating part, 17... Outer part, 18...
Inner part, 19...Introduction part, θ...Arrangement angle of intake hole, r...Arrangement distance of intake hole, D...Diameter of cylinder chamber.

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. It 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 the circumferential surface of the vortex-generating part is a substantially cylindrical surface facing the circumferential surface of the valve shaft of the intake valve. The width between the circumferential surface of the valve shaft of the intake valve and the circumferential surface of the vortex generating portion facing the intake valve is made wider in the outer portion on the cylinder chamber circumferential side than in the inner portion on the cylinder chamber center side,
It gradually narrows from the outer part to the inner part around the valve shaft, and the circumferential surface of the outer part of the vortex generating part is arranged almost along the circumferential surface of the cylinder chamber, and the outer part of the vortex generating part is wide. Connect the almost linear introduction part along the tangential direction, and adjust the height between the opening surface of the intake hole and the ceiling of the vortex generation part facing this by connecting the wide outer part to the narrow part around the valve stem. It is the same or decreases while reaching the inner part, and the average decrease amount is set within 0.18% of the diameter of the intake hole per degree around the valve stem, and the center of the end face of the cylinder chamber and the center of the intake hole are connected. The angle that the line makes with the line connecting the centers of the end faces of multiple cylinder chambers arranged in series is set within 70 degrees, so that the main flow of the intake air flowing through the intake passage is directed from the introduction part to the outer part of the vortex generation part. Flows between the circumferential surface and the circumferential surface of the valve shaft of the intake valve, passes through the intake hole, and flows into the cylinder chamber along the tangential direction of the portion of the circumferential surface adjacent to the intake hole,
An intake port for an internal combustion engine, characterized in that the intake port is configured to form a vortex flow that swirls along the circumferential surface of a cylinder chamber. 2. An intake port for an internal combustion engine according to claim 1, wherein the angle is set within 45 degrees. 3. The intake port of an internal combustion engine according to claim 1 or 2, characterized in that the distance between the center of the end face of the cylinder chamber and the center of the intake hole is set within 30% of the diameter of the cylinder chamber. .