JPS59180027A - Intake port of internal-combustion engine - Google Patents

Abstract

PURPOSE:To generate vortex flow in a stable manner, by constituting an intake passage from a main section and a vortex-flow generating section surrounding an intake valve at the end of the intake passage, varying the radius of the vortex-flow generating section along the circumference thereof, and specifying the height between the opening plane of an intake port and the top surface of the vortex-flow generating section. CONSTITUTION:An intake port is formed by opening a circular intake port 12 in a circular end face of a cylinder chamber 11 at the position thereof displaced from the center toward a peripheral portion. The intake port 12 is connected to an intake passage 15 and an intake valve 13 is provided in the intake port 12. The intake passage 15 is constituted from a vortex- flow generating section 16 communicated with the intake port 12 and surrounding the intake valve 13 at the end of the intake passage 15 and a main section 19 excluding the passage end. Here, the width between the outer surface of a valve shaft 14 of the intake valve 13 and the opposed inner surface of the vortex-generating section 16 is made greater at the outer portion 17 located near the peripheral surface of the cylinder chamber 11 than at the inner portion 18 located near the center of the cylinder chamber 11. Further, the height between the opening plane of the intake port 12 and the opposed top surface of the vortex-flow generating section 16 is made equal over the entire length from said outer portion 17 to the inner portion 18 or otherwise reduced gradually from the portion 17 to the portion 18. The average reduction rate of said height is selected to be within 0.18% of the diameter of the intake port 12 per unit degree in the turning angle around the valve shaft 14.

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.

Conventionally, this type of intake port has a
A helical intake boat in which the connecting end of the intake passage (1) with the intake hole (4) is formed into a spiral portion (2) that approaches the intake hole (4) while rotating around the valve shaft (3) of the intake valve. and, as shown in Figures 2 and 3, the intake hole (9) of the intake passage (6)
There is a tangential intake port whose connecting end with the cylinder chamber 00 is arranged along the tangential direction of a portion of the circumferential surface of the cylinder chamber 00 adjacent to the intake hole (9).

Comparing both intake boats, the helical intake boat has a spiral part (2) at the connecting end of the intake passage (1) to the intake hole (4).
Therefore, although a strong vortex can be generated in the cylinder chamber (5), the pressure loss in the intake passage (1) is large and the volumetric efficiency of the cylinder chamber (5) is low. In response to this,
Since the tangential intake port does not have a spiral part in the intake passage (6), the pressure loss in the intake passage (6) is small and the volumetric efficiency of the cylinder chamber (10) is high.
It is possible to strengthen the vortex that occurs at zero. Further, in the tangential intake port, the valve stem (7) of the intake valve is inserted into the center of the connection end of the intake passage (6) with the intake hole (9), and the valve stem guide cylinder (8) protrudes. Therefore, the intake passage (
The intake flow from 6) to the cylinder chamber 00 collides with the valve shaft (7) and branches into two branches, and these two branched flows collide and interfere after passing the valve shaft (7) position, resulting in a vortex flow in the cylinder chamber 00. becomes even weaker. Moreover, since the above-mentioned branching ratio of the intake air flow is not constant, the vortex flow becomes unstable.

As a result, in conventional intake ports, it is not possible to generate a moderately stable vortex flow without reducing volumetric efficiency.

Therefore, an object of the present invention is to provide an internal combustion engine that can generate a moderately stable vortex flow without reducing volumetric efficiency.
, is to provide a care boat.

The inventor of the present invention found that the reason why the pressure loss in the intake passage is large in the helical intake port is that the intake air flowing through the intake passage changes its flow direction significantly in a spiral manner at the spiral part of the vortex generation part. Yes, 1. The reason why the vortex is weak and unstable at the tangential intake port is that there is no vortex generator in the intake passage and the main flow of the intake air flowing through the intake passage collides with the valve stem of the intake valve. They focused on certain things and devised ways to eliminate these causes.

That is, in the intake port of an internal combustion engine in which the present invention has an intake hole opened at a position eccentric from the center of the end face of the cylinder chamber, an intake valve is provided in the intake hole, and the intake passage is connected, the intake passage is connected to the intake port. The intake valve is connected to the hole and consists of a vortex generating part at the end of the tr passage and an introduction part outside the end plate of this passage, and the width between the valve shaft circumferential surface of the intake valve and the circumferential surface of the vortex generating part facing it. In the outer part of the cylinder chamber circumferential side, the inside of the cylinder chamber -
Make the inner part of the D side wider, connect the introduction part to the wide outer part of the vortex generation part, and adjust the height between the opening surface of the intake hole and the ceiling of the vortex generation part facing this by adjusting the height around the valve stem. The range from the wide outer part to the narrow inner part is the same or decreases, and the average reduction amount is within 0% of the diameter of the intake hole per 7 degrees around the valve stem, that is, it is reduced. This is an intake port for an internal combustion engine.

In this intake port, the airflow flowing through the intake passage does not curve as much at the vortex generating portion as in the helical intake port, so the pressure loss in the intake passage is small, and therefore the volumetric efficiency of the cylinder chamber is high. In addition, since the main flow of the intake air flowing through the intake passage flows from the introduction part to the outer part of the vortex generation part and does not collide with the valve shaft of the intake valve, the tangential engine
A stronger and more stable vortex is generated than at the Ql port. Therefore, a moderately stable vortex can be generated without reducing the volumetric efficiency.

Next, examples of the present invention will be described.

First Embodiment (Refer to Figures 1 to 5) As shown in Figure 1 and Figure S, the intake port of the internal combustion engine of this example is located at the circular end face of the cylinder chamber 0]). ．． A circular intake hole 0 is opened at a position eccentric to the periphery from J-, and a poppet valve Oa is opened in the intake hole (1).
At the same time, the intake passage QfQ is connected, and the intake passage A is connected to the intake hole A and is connected to the vortex generating part 0 at the end of the passage surrounding the intake valve 0.1 and from the introduction part 09 outside the passage end plate. As shown in FIG. ) and the vortex generating part (]f90 facing this), the width between the circumferential surface of the cylinder chamber 01
)The outer part on the curve side is wider than the inner part on the center side of the cylinder chamber, and the outer part is made wider around the valve stem 04).
It gradually narrows from the inner part (I81), and connects the linear introduction part 4 to the wide outer part 071 of the vortex generating part OQ along its tangential direction, and kneads it with the opening surface of the intake hole 02. The height between the ceilings of the vortex generating part OQ facing the valve stem (14) is kept the same or gradually decreased from the wide outer part 07) to the narrow inner part 0 barrel around the valve stem (14), and The amount of reduction is 0 for the intake hole diameter d per 7 degrees around the valve stem 04).
It is set within 7g%.

In this intake port, the intake air flowing through the intake passage Q flows from the introduction part 09 into the vortex generation part 0Q,
It flows into the cylinder chamber αυ through the intake hole 02, and the main flow of the intake air flows from the axial center position of the introduction part (19) to the outer 4111 part of the vortex generating part (the circumferential surface of lη and the circumferential surface of the valve shaft (14). Flows into the cylinder chamber 01 through the intake hole 02)
The air flows into the cylinder along the tangential direction of the portion of its circumferential surface near the intake hole, forming a vortex flow that swirls along the cylinder chamber (1υ) curve.

In addition, in the intake port of this example, the reduction amount Δh of the ceiling height of the vortex generating part (+6) is set for each individual with respect to the diameter d of the intake hole, and the cylinder chamber (11) is
The strength of the vortex generated in the swirl ratio 8R and the intake passage (
When we calculated the pressure loss Δp for the country, we obtained the results shown in the diagram in Figure 4. That is, as shown in the upper part of the diagram, the swirl ratio SR does not change greatly depending on the magnitude of the above-mentioned decreasing piece Δh, and remains almost constant. In addition, as shown at the bottom of the diagram, the pressure loss Δp and the above reduction amount Δh
is the diameter d of the intake hole per 7 degrees around the valve stem 04). /
It is almost constant within 1%, but increases rapidly when it exceeds oig%f. Therefore, when Δh/d per 7 degrees is set within 07g5, an increase in pressure loss is prevented and the volumetric efficiency is increased.

Second Embodiment (See Figures 7 and g) The intake port of the internal combustion engine of this example is different from that of the previous example. 2 facing the circumferential surface of the valve shaft 04) of the intake valve.
It is formed by smoothly connecting two cylindrical surfaces, and
] The cylindrical circumferential surface of the side part (181 is arranged along the opening edge of the intake hole +IZ, and the cylindrical circumferential surface of the outer part 071 of the vortex generation part 1 is arranged at the outer position of the opening edge of the intake hole (+3) Then, a cylinder chamber (lυ
Introductory part with a rectangular cross section surrounded by 100 circles parallel to the end face of +I
Q, and this connection angle is set so that the main flow of the intake air from the introduction part 09 to the vortex generation part (+61) is the outer part 0 of the vortex generation part.
The angle is set to flow between the circumferential surface of 7) and the circumferential surface of the valve stem. Since the other points are the same as those in the previous example, the same reference numerals are given in FIG. 7 and the explanation will be omitted.

In the intake port of this example, the connection angle between the introduction part 09 and the outer part (1η) of the vortex generation part, specifically, the connection line between the aspect of the outer part αη of the vortex generation part and the outer surface of the introduction part 09 and the vortex generation part With respect to the connection surface (a) including the connection line between the peripheral surface of the inner part (18) of the part and the inner surface of the introduction part (19), the introduction part (]
! The angle α formed by the main flow of intake air flowing from J to the vortex generating portion OQ was set for each individual, and experiments were conducted for each of them. Then, as shown in the diagram in FIG. 5, the swirl ratio SR gradually decreases as the connection angle α becomes smaller than 60 degrees, and gradually decreases as the connection angle α exceeds 710 degrees.
When it exceeds 5 degrees, it decreases rapidly, and becomes a high value at 60 degrees or more and 110 degrees or less. When the connection angle α exceeds 735 degrees, the main flow of intake air flowing into the inlet part (] Similarly, the vortex is weak and unsettling. On the other hand, when the connection angle α becomes smaller than 0 degrees, the main flow of the intake air flows to the outer part of the vortex generating part (
Collision with the phase of Iη increases the pressure loss of the intake passage (IF9), lowers the volumetric efficiency of the cylinder chamber 01, and at the same time weakens the vortex flow due to the decrease in the intake flow rate.

When the connection angle α becomes larger than 710 degrees, a part of the main flow of intake air collides with the valve shaft (14) and also flows into the cylinder from the vortex generating part (I) through the intake hole (1"). Room (
The main flow of the intake air flowing into 1υ moves to the center side of the cylinder chamber, and the vortex becomes weaker. Therefore, the connection angle α is quickly increased from 60 degrees to 710 degrees, and the connection angle α is changed from the introduction part (19) to the vortex generation part ( When the main flow of the intake air reaching Iff flows between the circumferential surface of the outer portion of the vortex generating portion and the circumferential surface of the valve shaft 04), a tilted and stable vortex is generated.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional helical intake port, FIG. 2 is a perspective view of a conventional tangential intake port, and FIG. 3 is a plan view of a tangential intake boat. FIG. 1 is a perspective view of an intake port according to a second embodiment of the present invention, FIG. 5 is a plan view of the same intake port, and FIG. 6 is a period in which the ceiling height of the vortex generating part in the same intake port decreases. FIG. 3 is a diagram showing the relationship between the flow rate and the swirl ratio or pressure loss. FIG. 7 is a plan view of the intake port of the second embodiment;
The figure is a diagram showing the relationship between the swirl ratio and the connection angle between the introduction part and the outer part of the eddy current generating part in the same intake port. 11 Nijilinda chamber 12: Intake hole 13: Warm-up valve
14: Valve shaft 15: Intake passage 16: Vortex generating part 17: Outside part 18: Inside part 19: Introduction part 11-

Claims (2)

[Claims] (1) In an intake boat for an internal combustion engine in which an intake hole is opened at a position eccentric from the center of the end face of the cylinder chamber, an intake valve is provided in the intake hole, and the intake passage is connected, the intake passage is communicated with the intake hole. A beak is formed from the vortex generating part at the end of the passage surrounding the intake valve and the introduction part at the end of the passage, and the width between the circumferential surface of the valve shaft of the intake valve and the face of the vortex generating part facing this is defined as the cylinder chamber face. The outer part of the side is made wider than the inner part of the ID side of the cylinder chamber, and the introduction part is connected to the wide outer part of the vortex generating part, and the space between the opening surface of the intake hole and the ceiling of the vortex generating part facing it is connected to the wide outer part of the vortex generating part. The height is the same or decreases from the wide outer part to the narrow inner part around the valve stem, and the average decreasing lid is 0/g of the diameter of the intake hole per 7 degrees around the valve stem. An intake port of an internal combustion engine characterized by being set within %. (2) Adjust the connection angle between the introduction part and the outer part of the vortex generation part so that the main flow of intake air from the introduction part to the eddy flow generation part flows between the circumferential surface of the outer part of the vortex generation part and the circumference of the valve shaft. An intake port for an internal combustion engine according to claim 1, wherein the intake port is set at an angle.