JP3030413B2 - In-cylinder injection internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct injection type internal combustion engine for directly injecting fuel into a combustion chamber, and more particularly, to a direct injection type internal combustion engine in which a lean air-fuel mixture is burned in a stable state. About.

[0002]

2. Description of the Related Art Conventionally, in a diesel engine mainly using light oil or the like as an internal combustion engine, fuel is directly injected into a combustion chamber, and the fuel is spontaneously ignited by compressed air in the combustion chamber to obtain power. I have. In addition, various gasoline engines of direct injection type have been proposed in which fuel is directly injected into a combustion chamber to improve engine responsiveness.

[0003] The specific configuration of such a direct injection gasoline engine will be briefly described. A direct injection gasoline engine requires a spark plug as ignition means, and the spark plug is arranged in a combustion chamber. Is established. The injector is provided, for example, in a cylinder head on the intake valve side.

[0004] Even in such a direct injection internal combustion engine, it is desired to improve the fuel efficiency of the engine by forming a vortex-shaped intake air flow in the combustion chamber and performing lean combustion with a fuel leaner than the stoichiometric air-fuel mixture. Therefore, in order to form such a vortex-shaped intake flow, the intake flow from the intake port is taken in parallel with the piston top surface as much as possible, and thereafter, this intake flow is directed downward along the cylinder inner wall portion. A structure that generates a vortex-shaped intake flow has been proposed.

However, in order to generate a vortex intake air flow using such a structure, it is necessary to arrange the intake port as parallel as possible to the upper surface of the cylinder head. Location cannot be secured sufficiently. Therefore, for example, a strong vertical vortex (tumble flow) is formed in the combustion chamber as in the technique disclosed in JP-A-6-146886 so that the engine can be stably operated even in lean combustion. Conceivable.

[0006]

However, such a conventional technique has a problem that it is difficult to form a sufficiently strong tumble flow when the volume of the combustion chamber is increased to some extent. That is, as the volume of the combustion chamber increases, the intake air flow drawn into the cylinder also becomes stronger. However, as shown in FIG. 9, when the intake flow flows from the intake port 4 into the cylinder 1A, the intake flow Collides with the umbrella 62 of the intake valve 61, and intake air flows on both sides of the umbrella 62. Therefore, the intake valve 61 itself becomes an intake resistance, which becomes a hindrance factor when generating a vertical vortex in the cylinder 1A.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has been made in consideration of the above-described problem. It is an object of the present invention to provide an in-cylinder injection type internal combustion engine capable of forming the following.

[0008]

According to the first aspect of the present invention, there is provided an in-cylinder injection type internal combustion engine according to the present invention, wherein a combustion formed between an upper surface of a piston inserted into a cylinder and a lower surface of a cylinder head. A chamber, an intake opening end opening to the combustion chamber on one side of a reference plane including the center axis of the cylinder, an intake port extending upward from the intake opening end, and located on the other side of the reference plane. An exhaust port formed in the cylinder head and communicating with the combustion chamber via an on-off valve is disposed on a side of the combustion chamber on the side of the intake port so that an injection port faces the combustion chamber. An intake flow introduced into the combustion chamber by the intake port, wherein the intake air flows from the lower surface of the cylinder head toward the upper surface of the piston on one side of the reference surface along the central axis direction. From the top of the piston on the other side It is configured to form a vertical vortex having a streamline toward the lower surface direction of the Linda head, and the reference surface side half of the intake port is wider than the other half to promote the formation of the vertical vortex. The intake flow center of the intake port is eccentric to the reference surface side half, and the intake flow of the intake port is transferred from the intake opening end to the reference surface side half near the intake opening end of the intake port. A guide portion for guiding smoothly to the side wall side of the cylinder is formed.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the cross-sectional shape of the intake port is substantially semicircular near the intake opening end. It is characterized by being formed in a shape. Further, the in-cylinder injection type internal combustion engine of the present invention described in claim 3 is the above-described claim 1.
In addition to the configuration described above, the sectional shape of the intake port is substantially triangular in the vicinity of the intake opening end.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an in-cylinder injection type internal combustion engine according to an embodiment of the present invention; FIG. FIG. 2 is an overall view schematically showing an internal configuration, FIG. 3 is a front view showing an intake port thereof, and FIG.
FIG. 5 is a diagram showing a cross-sectional shape of the intake port, FIG. 5 is a schematic overall perspective view showing the configuration, FIG. 6 is a diagram for explaining the operation state, FIG. FIG. 8 is a view showing a modified example thereof, and is a view showing another example of the cross-sectional shape of the intake port.

First, the overall configuration of the direct injection internal combustion engine will be described. The cylinder head of this internal combustion engine is configured as a four-valve internal combustion engine having two intake valves and two exhaust valves for each cylinder. ing.

As shown in FIGS. 2 and 5, a combustion chamber 7 is formed between the piston 2 and the cylinder head 1. An intake port as an intake passage is provided in the cylinder head 1 of the combustion chamber 7. 4 and an exhaust port 5 as an exhaust passage are connected to each other. In addition, these intake and exhaust ports 4,
An intake valve 61 and an exhaust valve (not shown) are installed at the combustion chamber openings 4A and 5A, respectively. The combustion chamber openings 4A and 5A are opened and closed by these intake and exhaust valves. Reference numerals 51 and 52 shown in FIG. 2 indicate valve stems of the intake and exhaust valves.

As shown in FIG. 5, the combustion chamber 7 has a virtual surface including a central axis 42 of the cylinder 3A and an axis of a crankshaft (not shown) as a reference surface 40. , Two intake ports 4 are arranged, and two exhaust ports 5 are arranged on the other side of the reference surface 40.
(See FIG. 2). Further, as shown in FIG. 2, the ignition plug 20 is disposed at the center of the top of the combustion chamber 7 (that is, on the reference surface 40) or in the vicinity thereof.

Further, as shown in FIGS.
Each of the above-mentioned intake ports 4 is provided so as to be substantially upright from the cylinder head 1, and as shown in FIGS. 1 and 2, an opening 4 </ b> A of each of the intake ports 4 It is arranged slightly inclined. Therefore, the upper portion of the combustion chamber 7 of the engine on the intake valve side has a pent roof shape.

As shown in FIGS. 5 and 6, an injector 18 for supplying fuel to the combustion chamber 7 is provided on the intake port 4 side of the cylinder head 1. The injector 18 has an injection hole 18A at the tip end thereof facing the inside of the combustion chamber 7, and is configured to inject fuel directly into the combustion chamber 7.

The injector 18 is, for example,
The controller is controlled by a controller (not shown), so that a predetermined amount of fuel is injected at a predetermined injection timing. Here, the mounting portion of the injector 18 will be described.
The intake ports 4 are connected to the cylinder head 1 as described above.
Since it is provided substantially vertically upward, a sufficient space for mounting the injector 18 around the opening 4A of the intake port 4 can be secured.
Therefore, the degree of freedom in setting the positional relationship with the ignition plug 20 is large, so that the injector 18 can be installed at an optimal arrangement position for fuel injection.

As described above, the piston 2 is fitted into the cylinder 3A, and a concave portion (curved portion) 2A as shown in FIG. I have. The recess 2 </ b> A is provided in a portion of the top of the piston 2 below the intake port 4, and is formed by a downwardly convex bay curved surface. That is, this recess 2A
Is provided at a position eccentric to the intake port 4 side with respect to the reference surface 40, and is formed, for example, in a spherical shape curved downward and convexly.

On the top of the piston 2, below the exhaust port 5, there is formed an exhaust valve-side upper surface 2B which is close to the recess 2A and protrudes from the recess 2A. The side upper surface 2B is connected to the recess 2A. Thereby, as shown in FIG. 6, when the piston 2 reaches the end of the compression stroke, the recess 2A of the piston 2 and the cylinder inner wall 1A
And a compact combustion chamber 7 </ b> A surrounded by the cylinder head 1.

The main part of the present invention will now be described. In the in-cylinder injection type internal combustion engine, as shown in FIGS. 1 and 4 (a), a part of each intake port 4 has a substantially semicircular cross section. Is formed. As shown in FIGS. 4A to 4I, the intake port 4 having a substantially triangular cross section with a semicircular cross section has another shape different from the semicircular shape on the upstream side, and has a downstream shape on the downstream side. It is formed to have a substantially semicircular shape as approaching. Further, each cross-sectional shape as shown in FIGS. 4A to 4I is formed so as to be smoothly connected, so as not to obstruct the flow of the intake air flow.

As shown in FIG. 4A, in the vicinity of the intake opening 4A of the intake port 4, the intake port 4 is formed to have a substantially semicircular shape. The reference surface side half 40 is formed so as to be wider than the other half. Specifically, it is formed so that a straight portion (a widened portion) of a semicircular portion is located on the center side of the cylinder 3A, and an arc-shaped portion of the semicircular portion is formed on the side wall side of the cylinder 3A. -ing

On the other hand, as shown in FIGS. 1, 2 and 6, a half of the intake port 4 near the reference opening 40 near the intake opening end 4A is provided with the intake air flowing through the intake port 4 at the intake opening end. A raised portion 60 is formed as a guiding portion for smoothly guiding from 4A to the cylinder inner wall 1A side.
The raised portion 60 has a direction in which the reference plane 40 overlaps the cylinder center axis 42 and appears as a single line (ie, the state shown in FIG. 1).
When viewed from above, it is formed as a jump table slightly warped to the cylinder center axis 42 side, so that the flow of intake air is gathered in a direction away from the cylinder center 42 of the intake port 4.

The protruding portion 60 will be described in more detail. The protruding portion 60 eccentrically moves the intake flow center in the intake port 4 from the cylinder center axis 42 side to the cylinder inner wall side 1A near the intake opening end 4A of the intake port 4. It is provided to make it happen. Further, as described above, in the vicinity of the intake opening end 4A in the intake port 4, since the cross section of the intake port 4 is formed in a substantially semicircular shape in which the center side of the cylinder 3A is widened, it has passed through the intake port 4. The intake flow is
Cylinder 3 of intake port 4 near intake opening end 4A
A large amount of intake air flows to the center side of A (that is, the reference surface side half 40 side).

In addition, by providing the above-described raised portion 60 near the intake opening end 4A, near the intake opening end 4A, the flow of the intake air is guided by the raised portion 60, and the cylinder center of the intake port 4 is located at the center of the cylinder. It will be eccentric from the axis 42 side to the cylinder inner wall 1A side. The intake air flows toward the intake opening 4A with a change in angle in this way, so that when the intake valve 61 is opened, the intake air flows into the combustion chamber 7 from the cylinder inner wall 1A side of the intake opening 4A. . Thereby, the incident angle of the intake air flow to the valve head 62 during the intake becomes an acute angle, and the intake resistance at the valve head 62 is greatly reduced.

The intake opening 4A has a pent roof shape as described above, and the umbrella portion 62 of the intake valve 61 is disposed so that the cylinder center axis 42 side is upward. The angle of incidence on the umbrella 62 is acute. Thereby, as shown in FIG. 1, when the intake valve 61 is opened, most of the intake flow in the intake port 4 smoothly enters between the umbrella portion 62 of the intake valve 61 and the intake opening end 4A, It is possible to prevent the intake flow from directly colliding with the umbrella portion 62 of the intake valve 61 and disturbing the intake flow.

In addition, the intake air is prevented from flowing from the cylinder center 42 side of the intake valve 4 and the combustion chamber 7
Since a strong intake flow flows from the side closer to the cylinder inner wall 1A, a strong vertical vortex (tumble flow TF) in the clockwise direction in FIG. 1 can be formed in the cylinder 3A. And then, the piston 2 as described above
The formation of the vertical vortex (tumble flow TF) is promoted by the recess 2A.

On the other hand, as shown in FIG. 6, the upper surface 2 B of the piston 2 on the exhaust valve side and the exhaust port 5
A squish area 2C is formed between the side and the side. Thereby, as shown in FIGS. 2, 5 and 6, the intake air flowing from the intake port 4 flows toward the lower piston 2 and is then guided upward along the recess 2A of the piston 2 to be directed upward. As it flows, a tumble flow TF is formed.
Therefore, in the combustion chamber 7, the intake flow promotes the formation of the tumble flow TF along the recess 2A.

Further, at this time, a squish SF as shown in FIG. 6 is generated in the flow toward the ignition plug 20 by the squish area 2C. The squish SF is guided toward the exhaust valve side upper surface 2B and the upper surface of the combustion chamber 7 and flows toward the center of the top of the combustion chamber 7. Then, the squish SF and the tumble flow TF collide, and the flow of the air-fuel mixture is strengthened.

Since the in-cylinder injection type internal combustion engine as one embodiment of the present invention is configured as described above, during the intake stroke of the engine, the intake air flows from each intake port 4 to the opening of the intake port 4. It flows into the combustion chamber 7 through 4A. Further, the fuel is directly injected into the combustion chamber 7 from the injection hole 18A of the injector 18. In addition, injector 1
Since the fuel cell 8 is controlled by a controller (not shown), the fuel is injected from the injector 18 at an appropriate timing, and is mixed with the intake air to generate an air-fuel mixture.

At this time, since the intake port 4 is provided substantially upright, the intake air flowing into the combustion chamber 7 goes downward (toward the piston 2). As shown in FIG. 6, near the intake opening end 4A in the intake port 4, the cross section of the intake port 4 is formed in a substantially semicircular shape in which the center side of the cylinder 3A is widened. The intake air flow flows toward the center of the cylinder 3A of the intake port 4 near the intake opening end 4A (that is, the reference plane side half 40A).
Side), a lot of intake flow passes.

Further, by providing a raised portion 60 near the intake opening end 4A, near the intake opening end 4A, this flow of intake air is guided by the raised portion 60, and the cylinder is moved from the cylinder center axis 42 side of the intake port 4 to the cylinder. It is eccentric toward the inner wall 1A. In addition, since the intake air flows toward the intake opening 4A with the angle change in this manner, the incident angle of the intake air to the valve head 62 becomes acute, and the intake resistance at the valve head 62 is greatly reduced. Become.

The cylinder head 1 has a pent roof shape, and the head 62 of the intake valve 61 is
By arranging such that the side faces upward, the incident angle of the intake air flow with respect to the valve head 62 is further acute. This allows
The intake resistance by the intake valve 61 is greatly reduced, and a strong intake flow can be made to flow from the side of the combustion chamber 7 close to the cylinder inner wall 1A.

On the other hand, the intake air flowing downward from above the combustion chamber 7 collides with the recess 2A at the top of the piston 2 and is directed upward to the combustion chamber 7 along the curved surface of the recess 2A. change.

The intake port opening 4A is provided on one side of the cylinder head 1 partitioned by the reference surface 40, and the recess 2A is provided below the opening 4A so as to face the opening 4A. So that the intake air flow is
While flowing into the cylinder inner wall 1A side of A, it is guided by the curved surface of the recess 2A, becomes an upward flow toward the vicinity of the center of the top surface of the cylinder 3A along the recess 2A, and the tumble flow TF is formed.

Thereafter, the intake air flow is mixed with the fuel injected by the injector 18 in the combustion chamber 7, compressed and expanded (exploded) in the combustion chamber 7, and then discharged from the exhaust port 5. Now, as described above, the substantially upright intake port 4 is formed such that the half on the reference surface 40 side has a substantially semicircular shape wider than the other half, and the opening 4A of the intake port 4 is formed.
By providing a raised portion 60 for eccentricizing the intake air flow toward the cylinder inner wall 1A in the vicinity, when the intake air flows into the cylinder, the intake resistance caused by the intake air colliding with the intake valve head 62 is greatly reduced. Since it can be reduced, a stronger tumble flow TF can be formed.
As a result, a strong intake flow flows into the cylinder 3A from the side of the intake opening end 4A away from the cylinder center 43 (the side of the cylinder inner wall 3A). When such a strong intake flow flows into the cylinder 1A, Since the tumble flow TF is strengthened, the tumble flow TF can be sufficiently formed even with an engine having a large combustion chamber volume.

Further, by forming the tumble flow TF in this manner, the engine can be operated with a fuel mixture of a smaller amount than the stoichiometric air-fuel ratio without deteriorating the ignitability. Further, the air-fuel mixture reaches the vicinity of the spark plug 20 provided at the center of the top of the combustion chamber 7 while being sufficiently stirred by the tumble flow TF.
Good ignitability can be obtained, and a stable combustion state can be obtained.

Further, by making the intake port 4 substantially upright, a sufficient space for mounting the injector 18 in the cylinder head 1 is secured, and the degree of freedom in mounting the injector 18 is increased. As a result, the injector 1 is disposed at a position suitable for directly injecting fuel into the combustion chamber 7.
8 can be attached. In addition, when the flow coefficient and the tumble ratio of the in-cylinder injection type internal combustion engine are compared with those of the related art, the characteristics are as shown in FIG. Here, a line a shown in FIG. 7 shows characteristics of the direct injection internal combustion engine of the present invention, and a line b shows characteristics of a conventional direct injection internal combustion engine having an intake port.

As shown in FIG. 7, according to the in-cylinder injection type internal combustion engine of the present invention, the flow coefficient is hardly changed as compared with the conventional one, but the tumble ratio is greatly improved. In particular, this improvement in the tumble ratio is caused by the intake valve 4
It can be seen that this becomes remarkable when the valve lift amount is large. Next, a modified example of the embodiment of the present invention will be described. In the cylinder injection type internal combustion engine of this modified example, only the cross-sectional shape of the intake port is different from the above-described embodiment. The configuration is the same as that of the embodiment.

That is, in this modified example, FIGS.
As shown in (j), each intake port 4 is formed to have a substantially triangular cross section as it approaches the downstream side. Further, each cross-sectional shape as shown in FIGS. 8A to 8I is formed so as to change smoothly, so as not to obstruct the flow of the intake air flow. This triangular cross section is formed such that the reference surface side half 40 of the intake port 4 is wider than the other half similarly to the above embodiment. That is, it is formed so that the bottom side (the widened portion) of the triangular cross section is located on the center side of the cylinder 3A, and is formed on the side wall side of the other half cylinder 3A having a small cross sectional area.

The intake port 4 is also provided with a half of the reference plane 40 near the intake opening end 4A of the intake port 4.
The intake air flowing inside the cylinder is moved from the intake opening end 4A to the inner wall 1 of the cylinder.
A raised portion 60 that guides smoothly toward the A side is formed. In the IA-IA cross section shown in FIG. 8A, the protruding portion 60 appears on the left side in the figure. Also in this modified example, by configuring the cross section of the intake port 4 to be substantially triangular as described above, the same operation and effect as in the above embodiment can be obtained.

The sectional shape of the intake port 4 is as follows.
The shape is not limited to the semicircular or triangular shape as described above. If the half on the reference surface 40 side is wider than the other half near the opening end 4A of the intake port 4, Other shapes may be used. In the above-described embodiment and its modification, the in-cylinder injection type internal combustion engine is connected to the intake 2
It is described as a four-valve internal combustion engine with two valves and two exhaust valves.
The present invention is not limited to a four-valve internal combustion engine, but can be applied to, for example, a three-valve internal combustion engine having two intake valves and one exhaust valve, and various other internal combustion engines.

Further, regarding the detailed shape of the piston 2,
The present invention is not limited to the above-described embodiment and its modified example, and a strong tumble flow TF can be obtained in a compact combustion chamber.
Any shape can be used as long as it can be formed.

[0042]

As described above in detail, according to the in-cylinder injection type internal combustion engine of the present invention, the cylinder is formed between the upper surface of the piston inserted into the cylinder and the lower surface of the cylinder head. A combustion chamber, an intake opening end opening to the combustion chamber on one side of a reference plane including the center axis of the cylinder, an intake port extending upward from the intake opening end, and located on the other side of the reference plane. An exhaust port formed in the cylinder head and communicating with the combustion chamber via an on-off valve, and an injection port is disposed on a side of the combustion chamber on the side of the intake port so as to face the combustion chamber. The intake air introduced into the combustion chamber by the intake port is directed from the lower surface of the cylinder head to the upper surface of the piston on one side of the reference surface along the center axis direction. On the other side of the reference plane, from the top of the piston It is configured to form a vertical vortex having a streamline flowing toward the lower surface direction of the cylinder head, and the reference surface side half of the intake port is wider than the other half to promote the formation of the vertical vortex. The intake flow center of the intake port is eccentric to the reference surface side half, and the intake flow of the intake port is transferred from the intake opening end to the reference surface side half near the intake opening end of the intake port. With a configuration in which a guide portion that guides smoothly to the side wall side of the cylinder is formed,
There is an advantage that the intake resistance of the intake flow when flowing into the combustion chamber can be greatly reduced, and a strong longitudinal vortex can be formed in the combustion chamber. As a result, even in an engine having a relatively large combustion chamber volume, a vertical vortex can be sufficiently formed, and there is an advantage that a stable combustion state can be obtained even with a fuel leaner than the stoichiometric air-fuel ratio.

According to the cylinder injection type internal combustion engine of the present invention described in claim 2, in addition to the configuration of claim 1,
With the configuration in which the cross-sectional shape of the intake port is formed in a substantially semicircular shape near the intake opening end, of the intake flow in the intake port, the flow on the reference surface side half of the intake port is surely strengthened. There is an advantage that can be. According to a third aspect of the present invention, in addition to the configuration of the first aspect, the in-cylinder injection type internal combustion engine of the present invention has a cross-sectional shape of the intake port formed in a substantially triangular shape near the intake opening end. With this configuration, as in the second aspect, there is an advantage that, of the intake flow in the intake port, the flow on the reference surface side half of the intake port can be reliably increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a main portion of a direct injection internal combustion engine as one embodiment of the present invention, and illustrating a flow of an intake air flow.

FIG. 2 is an overall view schematically showing an internal configuration of a direct injection internal combustion engine as one embodiment of the present invention.

FIG. 3 is a front view showing an intake port in the direct injection internal combustion engine as one embodiment of the present invention.

FIGS. 4A to 4I are diagrams showing a cross-sectional shape of an intake port in a direct injection internal combustion engine as one embodiment of the present invention.

FIG. 5 is a schematic overall perspective view showing a configuration of a direct injection internal combustion engine as one embodiment of the present invention.

FIG. 6 is a diagram for explaining an operation state in the direct injection internal combustion engine as one embodiment of the present invention.

FIG. 7 is a diagram showing a flow coefficient characteristic and a tumble ratio characteristic in a direct injection internal combustion engine as one embodiment of the present invention.

FIGS. 8A to 8J show variations in a direct injection internal combustion engine as one embodiment of the present invention.

FIG. 9 is a schematic diagram showing a conventional direct injection internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 1A Cylinder inner wall 2 Piston 2A Concavity as a curved portion 2B Piston exhaust valve side upper surface 2C Squish area 3 Cylinder block 3A Cylinder 4 Intake port 4A Intake passage combustion chamber opening 5 Exhaust port 5A Exhaust passage combustion chamber opening 7 Combustion chamber 7A Compact combustion chamber 18 Injector 18A Injector injection hole 20 Spark plug 40 Reference surface 42 Cylinder center axis 51,52 Valve stem 60 Guide or raised portion 61 Intake valve 62 Valve body of intake valve TF Tumble flow SF Squish

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideyuki Oda 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Satoshi Yoshikawa 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Kenji Goshima 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (56) References JP-A-6-146886 (JP, A) JP Hei 4-143417 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02B 31/00 F02B 23/10 F02B 29/00 F02F 1/42

Claims (3)

(57) [Claims] 1. A combustion chamber formed between an upper surface of a piston inserted into a cylinder and a lower surface of a cylinder head, and intake air opening to the combustion chamber on one side of a reference plane including a central axis of the cylinder. An opening end, an intake port extending upward from the intake opening end, an exhaust port formed in the cylinder head so as to be located on the other side of the reference plane, and communicating with the combustion chamber via an on-off valve; An injector disposed on a side of the combustion chamber on the side of the intake port so as to face an injection port to the combustion chamber, wherein an intake air introduced into the combustion chamber by the intake port is supplied to the central axis; A longitudinal eddy flow having a streamline from one side of the reference surface toward the upper surface of the piston from the lower surface of the cylinder head on one side of the reference surface and from the upper surface of the piston to the lower surface of the cylinder head on the other side of the reference surface. To form In order to promote the formation of the vertical vortex, the reference surface side half of the intake port is wider than the other half, and the intake flow center of the intake port is eccentric to the reference surface side half. A guide portion for smoothly guiding the intake flow of the intake port from the intake opening end to the side wall of the cylinder is formed at a half of the reference surface near the intake opening end of the intake port. An in-cylinder injection type internal combustion engine characterized by the following. 2. The direct injection internal combustion engine according to claim 1, wherein a cross-sectional shape of the intake port is formed in a substantially semicircular shape near the intake opening end. 3. The direct injection internal combustion engine according to claim 1, wherein a cross-sectional shape of the intake port is formed in a substantially triangular shape near the intake opening end.