JP3523498B2 - Engine swirl intake port - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swirl type intake port used for various engines such as a direct injection diesel engine / gasoline engine or a gas engine.

[0002]

[Preconditions] The swirl type intake port of the engine of the present invention is, for example, as shown in Figs. 1-3 (present invention), or Figs.
As shown in (Prior Art 1), a device having the following prerequisite configuration is targeted.

FIG. 1 shows a first embodiment of a swirl type intake port of an engine of the present invention. 1 (A) is a cross-sectional plan view of the swirl type intake port, FIG. 1 (B) is a longitudinal side view thereof,
FIG. 1C is a vertical sectional front view thereof. 2 (A) is shown in FIG.
2 (B) to 2 (G) are cross-sectional views taken along the line BB to GG in FIG. 2 (A). FIG. 3 is a perspective view of the swirl type intake port of FIG. FIG. 6 is a perspective view of a swirl type intake port showing the prior art 1, and FIG. 7 is a transverse plan view of FIG.

The port inlet (2) of the swirl type intake port (1) of the engine is connected to the port upstream part (3) and the port midstream part (4).
-, And it connects to a valve opening (6) through a port downstream part (5) in order.

The port downstream portion (5) extends from the base end portion (7) of the port toward the tip portion (8) along the circumferential direction around the valve opening axis (9) of the valve opening (6). I will turn. Port downstream
The front end portion (8) of (5) is partitioned by the partition wall (10) with respect to the base end portion (7) of the port downstream portion (5) .

The valve opening ( 6 ) is closed by an intake valve (23).
In valve state, the tip end portion of the port downstream portion (5) (8) Karapo
Intake air should flow only to the base end ( 7 ) of the downstream part ( 5 )
The a forgive intake swirl maintain ventilation gap (24), said partition wall (10)
It is formed between the lower end surface of the and the intake valve (23).
is there.

[Advantages of premise configuration] (1). Mixing performance of intake air and fuel is enhanced. In the intake stroke of the engine, the intake air flowing in the swirl type intake port (1) is swirled in the port downstream portion (5) and causes a strong swirl in the cylinder chamber (31). Therefore, the mixing performance of the intake air and the fuel is enhanced, and the combustion performance is enhanced.

(2). Turbulence due to interference of intake air in the downstream part of the port (5) disappears. If the intake air flowing in the port downstream portion (5) flows from the distal end portion (8) of the port downstream portion (5) to the proximal end portion (7), the intermediate port portion (4) of the port downstream portion (5) The intake air flowing from the tip (8) interferes with the intake air flowing into (5) to generate a turbulent flow, which reduces the intake flow velocity and the swirl force to reduce the mixing performance. , Volume efficiency is reduced and output is reduced.

In the above premise, the intake air that has reached the tip portion (8) of the port downstream portion (5) is partitioned by the partition wall (10) to the base end portion (7) of the port downstream portion (5). Does not flow. Therefore, the "turbulent flow due to the interference of intake air in the port downstream portion (5)" is eliminated, the swirl force is strengthened, and the volumetric efficiency is enhanced.

[0010]

2. Description of the Related Art The following related art 1 has the above-mentioned premise. ○ Conventional technology 1. 6 to 7 (see Japanese Patent Laid-Open No. 58-1
FIG. 6 is a perspective view of a swirl type intake port showing the prior art 1, and FIG. 7 is a cross-sectional plan view of FIG.

Port upstream of the swirl type intake port (1)
(3) and the port midstream portion (4) are formed substantially horizontally, and the valve port (6) is much lower than the port lower surface (81) of the port midstream portion (4).

[0012]

In the above-mentioned prior art 1,
There are the following problems. (I). Volume efficiency is low. The swirl-type intake port (1) has a port upstream portion (3) and a port midstream portion (4) formed substantially horizontally, and the valve mouth (6) is much more marked than the port lower surface (81) of this port midstream portion (4). It is low.

Therefore, all of the intake flow that has flowed from the port inlet (2) through the port upstream part (3) into the port midstream part (4) swirls along the swirl shape of the port downstream part (5). Then, everything flows into the cylinder chamber as a swirl flow from the valve port (6). In this way, all of the intake flow is in the downstream part of the port.
The airflow resistance increases and the volumetric efficiency decreases due to the turning along the turning shape of (5), so that the output of the engine cannot be increased.

An object of the present invention is to do the following. (I). Sufficiently holds the swirl component of the intake air, while maintaining a strong swirl force of the intake air, increases the direct component of the intake air to increase volume efficiency. (B). By reducing the flow resistance of the direct component of the intake, further Ru enhances the volumetric efficiency.

[0015]

In order to solve the above-mentioned problems, the swirl type intake port of the engine according to the present invention has the following characteristic structure in order to solve the above-mentioned problems, for example, as shown in FIGS. It is characterized by having done.

FIG. 1 shows Embodiment 1 of the swirl type intake port of the engine of the present invention. 1 (A) is a cross-sectional plan view of the swirl type intake port, FIG. 1 (B) is a longitudinal side view thereof,
FIG. 1C is a vertical sectional front view thereof. 2 (A) is shown in FIG.
2 (B) to 2 (G) are cross-sectional views taken along the line BB to GG in FIG. 2 (A). FIG. 3 is a perspective view of the swirl type intake port of FIG.

Invention 1 Claim 1. Here, for convenience of explanation, in the opening cross-sectional area of the port inlet (2), the inlet inner edge (11) located on the inner side of the swirl type intake port (1) and the inlet located on the valve port (6) side. The opening surface portion (13) located near the lower edge (12) will be referred to as the inner-lower opening area (13). This inner lower opening area
The opening surface portion (14) located on the opposite side of (13) is called the outer upper opening region (14). The opening surface portion (15) between the inner-lower-side opening area (13) and the outer-upper-side opening area (14) is referred to as a central opening area (15).

In this case, the inner lower opening area
An imaginary straight line (16) connecting at least a part of (13) and a part of the valve mouth (6) extends over the entire length of the port upstream part (3), in the port midstream part (4), and in the port downstream. part (5) to fall within the port upstream portion (3) port middle portion (4) and a port downstream portion (5) that forms the shape of.

The basic shape of the axial cross section of each part of the swirl-type intake port (1) in the longitudinal direction is a quadrangle, a circle, or a vertically elongated oval as shown in FIGS. be a, be oval oblong, or, it is it is thought appropriate to any other shape.

[0020] Before SL port lower surface of the swirl-shaped intake port (1) (17) is brought from the port inlet (2) port upstream portion (3) to proceed to port midstream portion (4) via its outer-side edge (18)
On the other hand, the inner side edge (19) was formed in an inclined shape in which it gradually became lower.

Invention 2. Claim 2. Here, for convenience of explanation, the opening cross section of the port inlet ( 2 )
Located on the inner side of the swirl type intake port ( 1 ) of the product
The inner edge of the inlet (11) and the lower side of the inlet located on the valve mouth ( 6 ) side
Open the opening surface part (13) located near the edge (12) inward and downward.
It is called an opening area (13) . This inner lower opening area
Open the opening part (14) located on the opposite side of (13) to the outside.
Call it the mouth area (14) . Above inner opening area (13) and outer upper area
Ri central opening territory the opening surface portion (15) between the opening region (14)
We will call it area (15) .

In this case, the opening area near the inner bottom
A virtual straight line connecting at least a part of (13) and a part of the valve ( 6 )
And line (16) over its entire length, the port upstream portion (3) in Poe
To enter the middle part ( 4 ) and the downstream part ( 5 ) of the port.
In addition, the upstream part of the port ( 3 ) , the middle part of the port ( 4 ) , and the port
Forming a downstream portion ( 5 ) . The swirl type intake port
Basic shape of the shaft perpendicular cross-section in the length direction of each portion of the over bets (1)
To make a quadrangle shown in FIGS. 1 to 3 and to make a circle,
Make it a vertically long oval, or a horizontally long oval.
Or other arbitrary shapes can be considered as appropriate.
It

Inner side of the swirl type intake port ( 1 )
Surface (20), via a port inlet (2) port upstream portion (3)
As the process proceeds to the port midstream portion (4), versus its upper edge (21)
And its lower edge (22) is gradually displaced inward.
It was formed obliquely.

○ Invention 3. Claim 3. The present invention 3 is obtained by adding fraud and mitigating risk following configuration to the above invention 1. The inner side surface (20) of the swirl-type intake port (1) is moved from the port inlet (2) through the port upstream part (3) to the port midstream part (4) toward the upper edge (21) thereof. The lower edge (22) of the lever is formed in an inclined shape that is gradually displaced inward .

[0025]

DETAILED DESCRIPTION OF THE INVENTION hereinafter, the embodiment of the swirl-shaped intake port of an engine of the present invention will be described based on FIGS. 1-5. FIG. 1 shows Embodiment 1 of the swirl type intake port of the engine of the present invention. 1 (A) is a cross-sectional plan view of the swirl type intake port, FIG. 1 (B) is a longitudinal side view thereof, and FIG.
(C) is the vertical cross-sectional front view. 2 (A) is a cross-sectional plan view of the swirl type intake port of FIG. 1, FIG. 2 (B) -FIG.
2G is a cross-sectional view taken along the line BB of FIG. 2A. FIG. 3 is a perspective view of the swirl type intake port of FIG.

FIG. 4 is a diagram schematically showing the flow of intake air in the perspective view of the swirl type intake port of FIG. Figure 5
FIG. 2 is a diagram schematically showing the flow of intake air in the cross-sectional plan view of the swirl type intake port of FIG. 1 (A).

A swirl type intake port (1) is formed in a cylinder head (41) of a direct fuel injection type vertical diesel engine. The port inlet (2) at the start end of the swirl type intake port (1) opens to the lateral side surface of the cylinder head (41), and the valve port (6) at the end thereof opens to the lower surface of the cylinder head (41). . Port inlet of swirl type intake port (1)
(2) is communicated with the valve port (6) through the port upstream part (3), the port midstream part (4), and the port downstream part (5) in this order.

The downstream portion (5) of the port extends from the proximal end portion (7) of the port toward the distal end portion (8) along the circumferential direction around the valve opening axis (9) of the valve opening (6). I will turn. Port downstream
The upper surface (42) of (5) is formed in a continuous curved shape that continuously and smoothly descends over the entire length from the base end portion (7) to the tip end portion (8). The tip portion (8) of the port downstream portion (5) is separated from the base end portion (7) of the port downstream portion (5) by a partition wall (10).
That hide.

The basic shape of the cross section of the swirl type intake port (1) orthogonal to the axis is a quadrangle, and each corner is arcuate. The port entrance (2) has a square shape with rounded corners.

Of the opening cross-sectional area of the port inlet (2),
The opening inner surface edge (11) located on the inner side of the swirl type intake port (1) and the inlet lower edge (12) located on the valve opening (6) side are provided with an opening surface portion (13). , The inner bottom opening area (1
I will call it 3). The opening surface portion (14) located on the opposite side of the inner lower opening area (13) is replaced with the outer upper opening area (14).
Call. The inner lower opening area (13) and the outer upper opening area
An opening surface portion (15) between the opening (14) and the portion (14) will be referred to as a central opening region (15).

An imaginary straight line (16) connecting a part or all of the opening area (13) toward the inside and the bottom and a part of the valve opening (6) is provided along the entire length thereof in the port upstream part (3) and the port. The upstream part of the port so that it enters into the middle part (4) and the downstream part of the port (5).
(3) Form the port midstream part (4) and the port downstream part (5). The lower surface of the swirl type intake port (1) (1
As 7) progresses from the port inlet (2) through the port upstream part (3) to the port midstream part (4), the inner circumference side edge (19) is gradually lower than the outer circumference side edge (18). It is formed into an inclined shape.

The inner peripheral side surface (20) of the swirl type intake port (1) advances from the port inlet (2) through the port upstream portion (3) to the port midstream portion (4), and its upper edge (21). ), The lower edge (22) is formed in an inclined shape that gradually displaces toward the inner side. From the port inlet (2) of the swirl type intake port (1), the port upstream part (3) and the port midstream part
The shape of the port from the step (4) to the base end portion (7) of the port downstream portion (5) is formed in a curved shape that is reversed with respect to the turning direction of the port downstream portion (5). To do.

In the closed state in which the valve port (6) is closed by the intake valve (23), the distal end portion (8) of the port downstream portion (5) to the proximal end portion (7) of the port downstream portion (5). The ventilation gap (24) for maintaining the intake swirl that allows the intake air to flow only into the partition wall (10).
It is formed between the lower end surface of the and the intake valve (23). In FIG. 1, reference numeral (43) is a piston, and (44) is a combustion chamber.

[0034]

The swirl type intake port of the engine of the present invention has the following effects. See FIGS. 1 to 5. Figure 4
FIG. 4 is a diagram schematically showing the flow of intake air in the perspective view of the swirl type intake port of FIG. FIG. 5 is a diagram schematically showing the flow of intake air in the cross-sectional plan view of the swirl type intake port of FIG. 1 (A).

Invention 1 Claim 1. (I). It sufficiently holds the swirl component of the intake air and keeps the swirl force of the intake air strong, while increasing the direct component of the intake air to improve volumetric efficiency.

The flow of intake air in the swirl type intake port (1) is schematically shown in FIGS. In this schematic diagram,
The intake flow that has entered from the outside upper opening region (14) of the port inlet (2) is called the outside upper intake flow (34). Central opening area (15)
The inspiratory flow entering from is called the central part inspiratory flow (35). Then, the intake air flow entering from the opening region (13) toward the inside and below is referred to as the intake flow (33) toward and below the inside.

The upward intake air flow (34) flows into the port upstream (3).
・ Majorly wrap around the outer upper space inside the port midstream part (4) and the port downstream part (5), and pass through the valve port (6) from the downstream side region part of the port downstream part (5) to the cylinder chamber (31 ) Flows in as a strong swirl component.

The central part intake flow (35) is the above-mentioned outside intake flow.
At a position slightly closer to the center than (34), inside the port upstream part (3), the port midstream part (4) and the port downstream part (5), gradually shifting to the outer space part side from the center part space part. As it flows, it flows from the upstream region of the port downstream portion (5) through the valve port (6) into the cylinder chamber (31) as a swirl component.

As a result, the swirl component of the intake air flowing into the cylinder chamber (31) is sufficiently held, the swirl force of the intake air is strongly maintained, and the mixing performance of air and fuel is maintained high. Moreover, the intake air flow (33) that is closer to the inside and below is the central intake air flow (35).
Flows further along the inner lower space of the port upstream part (3), the port midstream part (4), and the port downstream part (5), further upstream of the port downstream part (5). From the area, through the valve opening (6), it flows straight into the cylinder chamber (31) as a direct component.

As a structure for this purpose, a virtual straight line (16) connecting at least a part of the inner-lower-side opening region (13) and a part of the valve opening (6) is provided over the entire length of the port upstream part ( 3)
The port upstream part (3), the port midstream part (4), and the port downstream part (5) are formed so as to enter the inside of the port middle part (4) and the inside of the port downstream part (5).

From this configuration, the intake air flow (33) that is close to the inside and below
Is the imaginary straight line (1) at the inner space below the port upstream part (3), the port midstream part (4) and the port downstream part (5).
Passing straight along almost 6), passing from the upstream region of the port downstream portion (5) through the valve port (6), it goes straight into the cylinder chamber (31) and flows as a direct component.

For this reason, the inwardly downward intake air flow (33) has a small degree of bending and has a high straightness, and the direct component of the intake air comprising the inwardly downward intake air flow (33) is strong and has a high flow velocity. Since the flow rate is large, the volumetric efficiency is greatly increased. Thus, Ru can increase the output of the engine effectively.

( B). The ventilation resistance of the intake air flow (33) inward and downward is reduced, and the volumetric efficiency is further enhanced. The port lower surface (17) of the swirl type intake port (1) is connected to the port inlet (2) through the port upstream portion (3) to the port middle portion.
As it goes to (4), the inner side edge (19) is gradually lowered with respect to the outer side edge (18).

From this structure, first, the inner circumference side edge (19)
In the passage portion where the opening area (13) at the inner bottom of the port inlet (2) and the valve opening (6) communicate with each other linearly along the imaginary straight line (16) as the Large passage cross-sectional area can be obtained. Next, the inward intake air flow (33) approaches the inner side edge (19) side by the amount that the inner side edge (19) is formed in an inclined shape that gradually decreases, and the valve opening ( It becomes easy to flow into the cylinder chamber (31) from a portion closer to the valve opening axis (6) of 6).

Then, the inward flow toward the inner and lower sides (3
3) becomes closer to a straight line over the entire length of the channel. Due to these three combined actions, the ventilation resistance of the inward-lower intake air flow (33) becomes smaller and the momentum of the flow becomes stronger, so that the flow rate of the direct component due to the inward-lower intake air flow (33) further increases. Volume efficiency is increased accordingly.

Invention 2. Claim 2. The invention 2 has the following effect in addition to the effect (a) of the invention 1. (C). The ventilation resistance of the intake air flow (33) inward and downward is reduced, and the volumetric efficiency is further enhanced. The inner side surface (20) of the swirl-type intake port (1) is connected to the port inlet (2), the port upstream part (3), and the port midstream part.
As the process proceeds to (4), the lower edge (22) of the upper edge (21) is gradually displaced inwardly toward the inner edge.

With this construction, the inner lower opening area (13) of the port inlet (2) and the valve opening (6) are reduced by the amount that the lower edge (22) of the port is gradually displaced inward. A large passage cross-sectional area can be obtained in the passage portion that linearly communicates along the virtual straight line (16). Next, the intake flow (33) that is closer to the inner and lower sides is formed by the amount that the lower edge (22) of the lower edge (22) is gradually displaced inward.
However, it becomes easier to flow into the cylinder chamber (31) from a portion closer to the valve opening axis (9) of the valve opening (6) and closer to the valve opening axis (9) of the valve opening (6).

The inflow flow (33) closer to the inner and lower sides becomes closer to a straight line over the entire length of the flow passage by the amount that the lower edge (22) is formed in an inclined shape that is gradually displaced inward. .
Due to these three combined actions, the ventilation resistance of the inward-lower intake air flow (33) becomes smaller, and the momentum of the flow becomes stronger, so that the flow rate of the direct component by the inward-lower intake air flow (33) further increases. As a result, the volumetric efficiency is increased and the output of the engine can be further improved.

Invention 3. Claim 3. The invention 3 has the effects (a) and (b) of the invention 1 described above.
In addition, the effect (C) of the invention 2 is also obtained.

[Brief description of drawings]

FIG. 1 shows Embodiment 1 of the swirl type intake port of the engine of the present invention. 1A is a transverse plan view of the swirl type intake port, FIG. 1B is a vertical side view of FIG. 1A, and FIG. 1C is a vertical front view of FIG. 1A.

2 (A) is a cross-sectional plan view of the swirl type intake port of FIG. FIG. 2B is a sectional view taken along line BB of FIG.
FIG. 2C is a cross-sectional view taken along the line CC of FIG. Figure 2 (D)
Is a cross-sectional view taken along the line D-D of FIG. 2 (E) is shown in FIG.
(A) EE sectional view taken on the line. 2 (F) is F of FIG. 2 (A).
-F line sectional view. FIG. 2G is a sectional view taken along the line GG of FIG.

3 is a perspective view of the swirl type intake port of FIG. 1. FIG.

FIG. 4 is a diagram schematically showing the flow of intake air in the perspective view of the swirl type intake port in FIG.

FIG. 5 is a diagram schematically showing the flow of intake air in a cross-sectional plan view of the swirl type intake port of FIG. 1 (A).

FIG. 6 is a perspective view of a swirl type intake port showing prior art 1.

7 is a cross-sectional plan view of FIG.

[Explanation of symbols]

1 ... Swirl type intake port. 2 ... Port entrance. 3 ...
Port upstream. 4 ... Port middle section. 5 ... Port downstream section. 6 ... Valve mouth. 7 ... Base end. 8 ... Tip. 9 ...
Center of valve opening. 10 ... Partition wall. 11 ... Inside edge of entrance. 12
… The lower edge of the entrance. 13 ... Inward opening area. 14 ... Outward opening area. 16 ... Virtual straight line. 17 ... Port bottom surface. 18 ... Outer side edge. 19 ... Inner side edge. 20
… Inner side. 21 ... Upper edge. 22 ... Lower edge. Two
3 ... Intake valve. 24 ... Ventilation gap for maintaining intake swirl.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Kosaka 64 Ishizukita-machi, Sakai City, Osaka Inside the Kubota Sakai Factory (56) Reference JP-A-2-271031 (JP, A) JP-A-58-122323 ( JP, A) JP 49-28703 (JP, A) JP 49-13513 (JP, A) Actual opening 57-139633 (JP, U) Actual opening 55-102028 (JP, U) (58) ) Fields surveyed (Int.Cl. ⁷ , DB name) F02B 31/00 F01L 3/06 F02F 1/42

Claims (3)

(57) [Claims] 1. A swirl type intake port (1) for an engine
Port inlet (2), port upstream (3), port midstream
(4) -and the port downstream (5) through the valve port (6)
To communicate, The port downstream part (5) goes from the base end part (7) to the tip part (8).
Towards the circumferential direction around the valve opening axis (9) of the valve opening (6)
And then swivel along the tip of the port downstream (5)
(8) is a partition wall (1) with respect to the base end (7) of the port downstream (5).
Division by (0)Then Said valve ( 6 ) Is the intake valve (twenty three) It is in the closed state when closed with
The downstream of the port ( 5 ) Tip of ( 8 ) From port downstream
( 5 ) Proximal end of ( 7 ) Intake that allows only inflow to
Ventilation gap for maintaining turning (twenty four) The partition wall (Ten) And the bottom surface of
Intake valve (twenty three) And formed between In the swirl type intake port of the engine, Of the opening cross-sectional area of the port inlet (2), swirl type suction
An inner inlet edge (11) located on the inner side of the air port (1),
Located near the lower entrance edge (12) located on the valve mouth (6) side
The opening surface part (13) is called the inner bottom opening area (13).
Opening surface part (1
If you decide to call 4) the outer upper opening area (14),
hand, At least a part of the inner lower opening area (13) and the valve opening (6)
A virtual straight line (16) connecting a part of the
In the upstream part (3), in the middle part of the port (4), and under the port
The upstream part of the port (3), the middle of the port so that it enters the flow part (5)
Form the flow section (4) and the port downstream section (5)Then Previous The lower surface (17) of the swirl type intake port (1) is
From the port entrance (2) to the upstream part of the port (3) to the middle part of the port
As you proceed to (4), turn the outer edge (18)
The inner side edge (19) is formed in a sloping shape that gradually decreases.
Was Characterized byRueThe swirl type intake port of the engine. 2. A swirl type intake port of an engine ( 1 ) of
Port entrance ( Two ) The port upstream ( Three ) ・ Port midstream
( Four ) . And downstream of port ( 5 ) Through the valve opening ( 6 ) To
To communicate, Port downstream ( 5 ) Is the proximal end of this ( 7 ) From the tip ( 8 ) To
Toward the valve ( 6 ) Valve opening axis ( 9 ) Around its circumference
Turn along the line, downstream of the port ( 5 ) Tip of
( 8 ) Is the port downstream ( 5 ) Proximal end of ( 7 ) Against compartment wall (1
0) Partition with Said valve ( 6 ) Is the intake valve (twenty three) It is in the closed state when it is closed with
The downstream of the port ( 5 ) Tip of ( 8 ) From port downstream
( 5 ) Proximal end of ( 7 ) Intake that allows only inflow to
Ventilation gap for maintaining turning (twenty four) The partition wall (Ten) And the bottom surface of
Intake valve (twenty three) And formed between In the swirl type intake port of the engine, The port entrance ( Two ) Of the opening cross-sectional area of
Qi port ( 1 ) Inner edge of the entrance located on the inner side of the (11) When,
Valve ( 6 ) Entrance lower edge (12) Located near and
Opening surface part (13) The inner bottom area (13) Call this
Inward opening area (13) Opening surface part located on the opposite side of (1
Four) The outer opening area (14) If you decide to call
hand, The inner lower opening area (13) And at least part of ( 6 )
A virtual straight line connecting a part of (16) Over its entire length
Upstream ( Three ) Inner / port middle section ( Four ) In and under port
Ryuube ( 5 ) Upstream of the port to enter inside ( Three ) ・ In the port
Ryuube ( Four ) . And downstream of port ( 5 ) To form The swirl type intake port ( 1 ) Inner side of (20) Is po
Entrance ( Two ) From port upstream ( Three ) Through the middle part of the port
( Four ) Its upper edge as you proceed to (twenty one) Against that side
edge (twenty two) Is formed so that it gradually displaces inward.
Was The swirl type intake port of the engine which is characterized by that. 3. The inner side surface (20) of the swirl type intake port (1) has an upper edge thereof as it goes from the port inlet (2) to the port upstream (3) to the port midstream (4). The swirl type intake port for an engine according to claim 1, wherein the lower edge (22) of the engine (21) is formed in an inclined shape that is gradually displaced inward.