JPH09256858A - Spark ignition engine of direct in-cylinder injection type - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of an air intake port suitable for a direct in-cylinder injection type spark ignition engine. SOLUTION: A bulkhead 10 to partition an air intake port 5 into a forward tumble port part 11 and a reverse tumble port part 12 is formed. The reverse tumble port part 12 is of the port shape to generate the reverse tumble to advance to a top wall 20 of a combustion chamber through a piston top surface 21 after the sucked air flowing into a cylinder is lowered along a cylinder wall 14 located immediately below the reverse tumble port part 12, and a control valve 15 to adjust the volume of the sucked air to be introduced from the forward tumble port part 11 into the cylinder is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an intake system in a direct cylinder injection type spark ignition engine.

[0002]

2. Description of the Related Art In order to stratify an air-fuel mixture that collects fuel near an ignition plug, an injector (fuel injection valve) faces the cylinder and direct fuel is injected into the cylinder. There is an injection spark ignition engine.

As a conventional direct cylinder injection type spark ignition engine, there is one in which an intake port is made to stand upright along a cylinder wall as disclosed in, for example, Japanese Patent Laid-Open No. 6-207542.

The intake air that has flowed into the cylinder from the upright intake port descends along the cylinder wall and then causes a reverse tumble that swirls along the top surface of the piston.

The fuel injected from the injector into the cylinder is atomized and vaporized in the course of swirling due to the reverse tumble, and liquid fuel is prevented from adhering to the ignition plug, and misfire is prevented and stabilized. Flammability is obtained.

[0006]

However, in such a conventional direct cylinder injection type spark ignition engine, the intake manifold has a structure in which the upright intake port is provided so as to penetrate through the upper portion of the cylinder head. Must be connected to the upper part of the cylinder head, which may cause a problem of increasing the total height of the engine.

Further, since the intake port is provided upright on the cylinder head, there is a problem that the degree of freedom of arrangement of the water jacket formed around the combustion chamber wall of the cylinder head is reduced.

The present invention has been made in view of the above problems, and an object thereof is to provide a structure of an intake port suitable for a direct cylinder injection type spark ignition engine.

[0009]

According to a first aspect of the present invention, there is provided a direct cylinder injection type spark ignition engine in which an intake port for introducing intake air into the cylinder, an exhaust port for exhausting exhaust gas from the cylinder, and an inside of the cylinder. In a direct cylinder injection type spark ignition engine including an injector for injecting fuel and a spark plug for igniting an air-fuel mixture in a cylinder, a partition wall for partitioning the intake port into a forward tumble port portion and a reverse tumble port portion is formed. ,
The tumble port is a reverse tumble port in which the intake flow that has flowed into the cylinder goes through the ceiling wall of the combustion chamber facing the forward tumble port, goes down the cylinder wall, and then advances to the piston top The forward tumbling section is designed so that the intake flow that has flowed into the cylinder has a port shape that causes reverse tumbling in which the intake flow descends along the cylinder wall located directly below the reverse tumble port section and then advances to the combustion chamber ceiling wall via the piston top surface. A tumble adjusting means for adjusting the amount of intake air introduced into the cylinder from the port section is provided.

According to a second aspect of the present invention, there is provided a direct cylinder injection type spark ignition engine in which the forward tumble port portion is inclined so as to face a cylinder wall on the exhaust port side, and a reverse tumble is provided. The downstream end of the port portion is curved so as to stand upright along the cylinder wall on the intake port side.

A direct cylinder injection type spark ignition engine according to a third aspect is the invention according to the first or second aspect,
The partition wall is formed by twisting so that the position of the reverse tumble port portion moves from the upper end to the lower end of the forward tumble port portion from the upstream end portion to the downstream end portion of the intake port.

A direct cylinder injection type spark ignition engine according to a fourth aspect of the present invention is the same as the first or second aspect of the present invention.
A partition wall is formed so that the reverse tumble port portion is located below the forward tumble port portion from the upstream end portion to the downstream end portion, and the downstream end portion of the partition wall is curved so as to be substantially parallel to the cylinder center line. Form.

According to a fifth aspect of the present invention, there is provided a direct cylinder injection type spark ignition engine according to the first aspect of the present invention, wherein the first tumble port portion of each cylinder communicates with the first collector portion. And a second collector section in which the reverse tumble port section of each cylinder communicates with each other, and a control valve for opening and closing the inlet section of the first collector section as tumble adjusting means,
Is provided.

[0014]

In the direct cylinder injection type spark ignition engine according to the first aspect, the intake flow flowing into the cylinder through the forward tumble port portion is directed to the combustion chamber ceiling wall facing the forward tumble port portion in the cylinder. After that, it descends along the cylinder wall and then advances to the top surface of the piston to generate a forward tumble that turns.

On the other hand, the intake flow that flows into the cylinder through the reverse tumble port section descends along the cylinder wall on the intake port side, then advances to the combustion chamber ceiling wall through the piston top surface and swirls in the reverse tumble. Occur.

In the operating state in which the forward tumble port section is closed by the tumble adjusting means, the fuel injected from the injector into the cylinder once descends along the cylinder wall on the intake port side due to this reverse tumble, so that the spark plug is discharged. It is possible to prevent the liquid fuel from directly adhering and prevent misfire.

In an operating state in which the forward tumble port portion is opened by the tumble adjusting means, intake air is divided into the forward tumble port portion and the reverse tumble port portion and is sucked into the cylinder, so that the port area is expanded and the intake air of the engine is increased. The charging efficiency can be improved, and a homogeneous air-fuel mixture can be created by the gas flow generated in the cylinder through each of the forward tamper port portion and the reverse tamper port portion, thereby improving the output performance.

In the direct cylinder injection type spark ignition engine according to the second aspect of the present invention, since the reverse tumble port portion has a structure which is largely curved in the middle thereof, even if the downstream end portion is made to stand upright along the cylinder wall, The intake manifold can be connected to the side wall of the cylinder head by opening the upstream end of the side wall of the cylinder head.

As a result, the height of the engine is reduced and the water jacket formed around the combustion chamber wall of the cylinder head is smaller than that of the conventional apparatus having the upright intake port penetrating the upper portion of the cylinder head. The degree of freedom of arrangement can be increased.

In the direct cylinder injection type spark ignition engine according to claim 3, the partition wall is twisted so that the reverse tumble port portion moves from the upper side to the lower side of the forward tumble port portion from the upstream end portion to the downstream end portion thereof. Due to the structure, the center of the passage of the reverse tumble port is greatly curved in the front view, strengthening the velocity component in the downward direction given to the intake flow flowing into the cylinder through the reverse tumble port, and strengthening the power of the reverse tumble. be able to.

In the direct cylinder injection type spark ignition engine according to the fourth aspect, since the downstream end of the reverse tumble port portion is upright along the cylinder wall, it flows into the cylinder through the reverse tumble port portion. The velocity component in the descending direction given to the intake air flow can be strengthened, and the power of the reverse tumble can be strengthened.

In the direct cylinder injection type spark ignition engine according to the fifth aspect of the present invention, it is necessary to provide a control valve for each cylinder due to the structure provided with a control valve for opening and closing the inlet of the first collector section as the tumble adjusting means. No, the number of parts can be reduced.

[0023]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 2, two intake ports 5 and two exhaust ports 23 are opened facing each other in the combustion chamber ceiling wall 20 inclined in a pent roof type.

As shown in FIG. 1, the spark plug 4 faces the center of the combustion chamber 3, and the two intake valves 7 and the two exhaust valves (not shown) face each other so as to sandwich the spark plug 4. It is provided.

An injector 6 is provided which faces the combustion chamber 3 from the side of the ceiling wall 20 of the combustion chamber. The injector 6 is located on the side of the two intake valves 7 and in the middle of the intake valves 7 and faces the combustion chamber 3.

The injector 6 is arranged so as to be inclined with respect to the top surface 21 of the piston 1. The center line of the fuel spray injected from the injection port of the injector 6 is arranged so as to incline downward at a predetermined angle with respect to the horizontal line.

In the compression stroke in which the piston 1 rises, most of the fuel spray injected from the injection port of the injector 6 passes between the intake valves 7 toward the piston top surface 21 and a part thereof. Touches the back side of the umbrella of each intake valve 7.

As each intake valve 7 is opened, air is drawn into each cylinder from each intake port 5. Piston 1
The injector 6 opens during the compression stroke in which the fuel pressure rises, and fuel is injected into the combustion chamber 3. The air sucked into the cylinder is ignited and burned through the spark plug 4 while the air is compressed by the piston. The burned gas is discharged from each exhaust port as the exhaust valve is opened during the exhaust stroke in which the piston 1 rises after the piston 1 is lowered and the rotational force is taken out via the crankshaft. Each of these steps is continuously repeated.

The upstream end of each intake port 5 opens to the side wall of the cylinder head 19, and the central partition wall 2 extends from the middle thereof.
V-shaped branch through 7 and each downstream end is a combustion chamber ceiling wall 2
It is open to zero.

Each intake port 5 has a forward tumble port section 1
1 and the reverse tumble port portion 12 are respectively partitioned via a partition wall 10.

The center of the passage of the forward tumble port portion 11 extends linearly in the front view of FIG. 1, and faces the combustion chamber ceiling wall 20 and the cylinder wall 14 on the side where the exhaust ports 23 are opened. The forward tumble port portion 11 is more inclined than the reverse tumble port portion 12 with respect to the cylinder center line.

In the reverse tumble port portion 12, the center of the passage is largely curved downward in the front view of FIG.
The downstream end thereof is formed to stand upright along the cylinder wall 14 on the side where the intake port 5 is open.

A protrusion 18 is formed at the downstream end of the partition wall 10 and projects toward the cylinder wall 14 on the side where the intake port 5 is opened. The downstream end of the reverse tumble port portion 12 stands upright along the cylinder wall 14 via the protrusion 18.

The partition wall 10 is formed by being twisted symmetrically by 180 degrees from its upstream end portion to its downstream end portion. As a result, the position of the reverse tumble port portion 12 moves from the upper side to the lower side of the forward tumble port portion 11 from the upstream end portion to the downstream end portion of the intake port 5, and the passage center thereof is directed downward in the front view of FIG. Bends greatly.

As shown in FIG. 4, at the upstream end of the intake port 5, the partition wall 10 extends substantially horizontally, and the reverse tumble port portion 12 is located above the forward tumble port portion 11.

As shown in FIG. 5, in the middle of the intake port 5, the reverse tumble port portion 12 which is branched into two is located inside the forward tumble port portion 11 which is also branched into two. The cross section of each partition wall 10 is curved in an arc shape, and the forward tumble port portion 11 has a crescent cross section.

As shown in FIG. 6, at the downstream end of the intake port 5, the reverse tumble port portion 12 has the forward tumble port portion 1
It is located below 1. The partition wall 10 is bent in a dogleg shape in cross section, and the reverse tumble port portion 12 is defined so as to open toward the central portion of the combustion chamber 3.

The downstream end of the partition wall 10 is close to the umbrella back portion of the intake valve 7 in the valve closing position, and the passage length of the reverse tumble port portion 12 is secured to the maximum.

As a tumble adjusting means for adjusting the amount of intake air introduced from the forward tumble port portion 11 into the cylinder, a butterfly type control valve 15 for opening and closing the inlet portion of the forward tumble port portion 11 is provided.

As shown in FIG. 3, the oval control valve 15 is rotatably accommodated in an inlet portion 26 for the forward tumble port portion 11 formed in the intake manifold 25 via a shaft 27. Shaft 2
7 rotates via an actuator 16.

The control unit 17 controls the control valve 1 in the stratified combustion region of a predetermined low / medium speed / low / medium load region.
5 is fully closed, and the control valve 15 is fully opened in a homogeneous combustion region of a predetermined high speed / high load region.

A spherical cavity 2 is formed in the top surface 20 of the piston 1. The cavity 2 is formed so as to be offset from the center line of the cylinder so as to face the reverse tumble port portion 12, and guides the intake flow flowing into the cylinder from the reverse tumble port portion 12 to the vicinity of the spark plug 4. ing.

With the above construction, the operation will be described.

When the control valve 15 is fully closed in the stratified combustion region of a predetermined low / medium speed / low / medium load region, most of the intake air is taken into the cylinder through the reverse tumble port 12. The intake air flowing into the cylinder through the reverse tumble port portion 12 descends toward the piston 1 along the cylinder wall 14 as shown by an outline arrow in FIG.
A reverse tumble that rises and swirls up to the center of the combustion chamber 3 along the cavity 2 recessed in the top surface 20 of the is generated.

Due to the structure in which the partition wall 10 is twisted symmetrically by 180 degrees and the reverse tumble port portion 12 moves from the upper side to the lower side of the forward tumble port portion 11 from its upstream end portion to its downstream end portion, the reverse tumble port portion 12 is formed. Is strongly curved in the front view of FIG. 1, and strengthens the velocity component that descends along the cylinder wall 14 given to the intake flow flowing into the cylinder through the reverse tumble port portion 12 to strengthen the power of the reverse tumble. You can

In this way, strong reverse tumble is generated in the cylinder, so that the air-fuel mixture that collects the fuel injected from the injector 6 into the cylinder in the vicinity of the spark plug 4 is stratified, and the gas flow of the reverse tumble causes it. The propagation of flame is promoted. As a result, the limit value of the lean air-fuel ratio at which combustibility is ensured is expanded, and fuel consumption is reduced.

The fuel injected into the cylinder from the injector 6 once descends due to this reverse tumble, so that it is possible to prevent the liquid fuel from directly adhering to the ignition plug 4 and prevent misfire. That is, the fuel injected into the cylinder is heated by the piston 1 in the process of swirling along the cavity 2 of the piston 1 due to this reverse tumble, and the atomization and vaporization thereof progress, and the fuel is ignited by the spark plug 4.
In addition, in the operating state in which the control valve 15 is closed, most of the intake air flows into the cylinder from the reverse tumble port section 12 to increase the intake air flow rate. Therefore, of the fuel spray injected from the injector 6, the fuel adhering to the umbrella back of each intake valve 7 is blown away by the high-speed intake flow, and the fuel and air are mixed.

When the control valve 15 is fully opened in the homogeneous combustion region of a predetermined high speed / high load region, the intake air is divided into the forward tumble port portion 11 and the reverse tumble port portion 12 substantially evenly and is sucked into the cylinder. Therefore, the port area is enlarged, and the intake charging efficiency of the engine can be increased.

The intake flow flowing into the cylinder through the forward tumble port section 11 descends along the cylinder wall 14 via the combustion chamber ceiling wall 20 on the exhaust port 23 side, as shown by the black arrow in FIG. After that, a forward tumble is generated in which the piston moves to the top surface 21 of the piston and turns. On the other hand, the intake flow that flows into the cylinder through the reverse tumble port section 12 descends along the cylinder wall 14 on the intake port 5 side and then advances toward the piston 1 as shown by the white arrow in FIG. , Piston 1
A reverse tumble that rises and swirls up to the center of the combustion chamber 3 along the cavity 2 recessed in the top surface 20 of the is generated. In this way, the gas flow generated in the cylinder creates a homogeneous mixture, thereby improving the output performance.

Since the reverse tumble port portion 12 has a structure which is largely curved in the middle thereof, the downstream end portion thereof has a cylinder wall 1
4 upright, the upstream end of the intake manifold 2 is opened to the side wall portion of the cylinder head 19 and the intake manifold 2
5 can be connected to the side wall of the cylinder head 19. As a result, the height of the engine is reduced and the degree of freedom of arrangement of the water jacket formed around the combustion chamber wall of the cylinder head is reduced as compared with the conventional device having an upright intake port that penetrates the upper portion of the cylinder head. Can be increased.

Next, the embodiment shown in FIG. 9 will be described. The parts corresponding to those in FIG. 1 are designated by the same reference numerals.

An intake manifold 30 is connected to the side wall of the cylinder head 19. The intake manifold 30 is partitioned into a first collector portion 31 and a second collector portion 32 via a partition wall 33.

As shown in FIG. 10, the forward tumble port section 11 of each cylinder communicates with the first collector section 31 provided in the four-cylinder engine. The reverse tumble port section 12 of each cylinder communicates with the second collector section 32.

A throttle valve 34 is provided at the inlet of the intake manifold 30. Throttle valve 3
4 throttles intake air in conjunction with the accelerator pedal.

As a tumble adjusting means for adjusting the amount of intake air introduced into the cylinder from the forward tumble port section 11, a butterfly type control valve 15 for opening and closing the inlet section 36 of the first collector section 31 is provided.

The oval control valve 15 has
It is rotatably accommodated in the inlet portion 36 of the first collector portion 31 formed in the intake manifold 25 via the shaft 27. The shaft 27 rotates via the actuator 16.

The control unit 17 controls the control valve 1 in the stratified combustion region in a predetermined low / medium speed / low / medium load region.
5 is fully closed, and the control valve 15 is fully opened in a homogeneous combustion region of a predetermined high speed / high load region.

In this case, it is not necessary to provide the control valve 15 for each cylinder, and the number of parts can be reduced.

Next, the embodiment shown in FIGS. 11 and 12 will be described. 1 and 2 are denoted by the same reference numerals.

Each intake port 5 has a forward tumble port section 51.
And the reverse tumble port section 52 through the partition wall 50.

The forward tumble port portion 51 has its passage center extending linearly in the front view of FIG. 11 and faces the combustion chamber ceiling wall 20 and the cylinder wall 14 on the side where the exhaust ports 23 are opened.

In this embodiment, the partition wall 50 is not twisted and its cross section extends substantially horizontally. The reverse tumble port section 52 is located below the forward tumble port section 51.

The downstream end 53 of the partition wall 50 is curved so as to be substantially parallel to the cylinder center line. As a result, the reverse tumble port portion 52 has its passage center largely curved downward in the front view of FIG. 11, and its downstream end portion stands upright along the cylinder wall 14 on the side where the intake port 5 opens. Is formed as.

As a tumble adjusting means for adjusting the amount of intake air introduced into the cylinder from the forward tumble port portion 51, a butterfly type control valve 15 for opening and closing the inlet portion of the forward tumble port portion 51 is provided.

As shown in FIG. 13, the elliptical control valve 15 is rotatably accommodated in the inlet portion 26 to the forward tumble port portion 51 formed in the intake manifold 25 via the shaft 27. The shaft 27 rotates via the actuator 16.

With the above arrangement, the operation will be described.

When the control valve 15 is fully closed in the stratified combustion region of a predetermined low / medium speed / low / medium load region, most of the intake air is sucked into the cylinder through the reverse tumble port portion 52. The intake air flowing into the cylinder through the reverse tumble port portion 52 descends toward the piston 1 along the cylinder wall 14 as shown by an outline arrow in FIG.
A reverse tumble that rises and swirls up to the center of the combustion chamber 3 along the cavity 2 recessed in the top surface 20 of the is generated.

Since the downstream end portion 53 of the reverse tumble port portion 52 stands upright along the cylinder wall 14, the velocity component in the descending direction given to the intake flow flowing into the cylinder through the reverse tumble port portion 52 is strengthened. , The power of reverse tumble can be strengthened.

In this way, the strong reverse tumble is generated in the cylinder, so that the fuel mixture injected from the injector 6 into the cylinder is collected in the vicinity of the spark plug 4, and the mixture is stratified. The propagation of flame is promoted. As a result, the limit value of the lean air-fuel ratio at which combustibility is ensured is expanded, and fuel consumption is reduced.

When the control valve 15 is fully opened in a homogeneous combustion region of a predetermined high speed / high load region, the intake air is divided into the forward tumble port portion 51 and the reverse tumble port portion 52 substantially evenly and is sucked into the cylinder. In this way, the port area is expanded to increase the intake charge efficiency of the engine, and the gas flow generated in the cylinder creates a homogeneous mixture, thereby improving the output performance.

[0072]

As described above, according to the direct cylinder injection type spark ignition engine according to the first aspect, the intake flow that flows into the cylinder through the normal tumble port portion is forward tumble port in the cylinder. While going down to the top surface of the piston after descending along the cylinder wall through the combustion chamber ceiling wall facing the section, a forward tumble that swirls is generated, while the intake flow flowing into the cylinder through the reverse tumble port section is After descending along the cylinder wall on the intake port side, it goes through the top surface of the piston to the combustion chamber ceiling wall to generate a reverse tumble that swirls,
The tumble adjusting means closes the forward tumble port section. It is possible to prevent the liquid fuel from directly adhering to the spark plug in an operating state and prevent misfire, and the tumble adjusting section opens the forward tumble port section. In the operating state, the port area is expanded to increase the intake charge efficiency of the engine, and a homogeneous air-fuel mixture is created by the gas flow generated in the cylinder through each of the forward tumbler port section and the reverse tumbler port section, which improves the output performance. It can be improved. Further, it is not necessary to change the arrangement of the intake port with respect to the cylinder head, and it can be easily implemented by adding a partition wall.

According to the direct cylinder injection type spark ignition engine of the second aspect, since the reverse tumble port portion is largely curved in the middle thereof, even if the downstream end thereof is made to stand upright along the cylinder wall. , The upstream end of which can be opened to the side wall of the cylinder head, and the intake manifold can be connected to the side wall of the cylinder head, as compared with a conventional device having an upright intake port that penetrates the upper part of the cylinder head. It is possible to reduce the height of the engine and increase the degree of freedom in arranging the water jacket formed around the wall of the combustion chamber of the cylinder head.

According to the direct cylinder injection type spark ignition engine of the third aspect, the partition wall is twisted so that the reverse tumble port portion extends from the upper end to the lower end of the forward tumble port portion from the upstream end portion to the downstream end portion thereof. Therefore, the center of the passage of the reverse tumble port is greatly curved in the front view, and the descending velocity component given to the intake flow flowing into the cylinder through the reverse tumble port is strengthened. The power can be strengthened.

According to the direct cylinder injection type spark ignition engine of the fourth aspect, since the downstream end of the reverse tumble port portion is upright along the cylinder wall, the inside of the cylinder passes through the reverse tumble port portion. It is possible to strengthen the velocity component in the downward direction given to the intake air flow that flows into the engine and strengthen the power of the reverse tumble.

According to the direct cylinder injection type spark ignition engine of the fifth aspect, since the tumble adjusting means is provided with the control valve for opening and closing the inlet portion of the first collector portion, the control valve is provided for each cylinder. The number of parts can be reduced because it is not necessary to provide the parts.

[Brief description of drawings]

FIG. 1 is a sectional view of an intake port and the like showing an embodiment of the present invention.

FIG. 2 is a plan view of a combustion chamber ceiling wall and the like.

FIG. 3 is a block diagram of a control valve of the same.

FIG. 4 is a sectional view of the intake port along the line AA of FIG.

5 is a sectional view of the intake port, which is also taken along the line BB of FIG.

FIG. 6 is a sectional view of the intake port along the line CC of FIG.

FIG. 7 is an explanatory view showing the flow of intake air when the control valve is closed.

FIG. 8 is an explanatory view showing the flow of intake air when the control valve is opened.

FIG. 9 is a cross-sectional view of an intake port, an intake manifold and the like showing another embodiment.

FIG. 10 is a sectional view of the intake manifold taken along the line D-D of FIG. 9.

FIG. 11 is a sectional view of an intake port and the like showing still another embodiment.

FIG. 12 is a plan view of a combustion chamber ceiling wall and the like.

FIG. 13 is a block diagram of a control valve of the same.

[Explanation of symbols]

 1 Piston 2 Cavity 3 Combustion Chamber 4 Spark Plug 5 Intake Port 6 Injector 7 Intake Valve 10 Partition Wall 11 Forward Tumble Port Part 12 Reverse Tumble Port Part 15 Control Valve 18 Projection 19 Cylinder Head 20 Combustion Chamber Ceiling Wall 21 Piston Top 25 Intake Manifold 30 Intake manifold 31 First collector part 32 Second collector part 50 Partition wall 51 Forward tumble port part 52 Reverse tumble port part 53 Partition wall downstream end part

Claims (5)

[Claims] 1. An intake port for introducing intake air into a cylinder, an exhaust port for exhausting exhaust gas from the cylinder, an injector for injecting fuel into the cylinder, and a spark plug for igniting an air-fuel mixture in the cylinder. In the direct in-cylinder injection spark ignition engine equipped with, a partition wall that divides the intake port into a forward tumble port portion and a reverse tumble port portion is formed, and the intake flow that has flowed into the cylinder at the forward tumble port portion faces the forward tumble port portion. A port shape that causes forward tumbling that advances to the piston top surface after descending the cylinder wall through the combustion chamber ceiling wall, and the intake flow that has flowed into the cylinder at the reverse tumble port is located directly below the reverse tumble port. After descending along the cylinder wall, it has a port shape that causes reverse tumble that advances to the combustion chamber ceiling wall through the piston top surface. Direct cylinder injection type spark ignition engine comprising the tumble adjusting means for adjusting the amount of intake air to be introduced into. 2. The forward tumble port portion is inclined so as to face a cylinder wall on the exhaust port side, and the downstream end portion of the reverse tumble port portion is curved so as to stand upright along the cylinder wall on the intake port side. The direct in-cylinder injection type spark ignition engine according to claim 1. 3. The partition wall is formed by twisting so that the position of the reverse tumble port portion moves from the upper side to the lower side of the forward tumble port portion from the upstream end portion to the downstream end portion of the intake port. Item 1. A direct cylinder injection type spark ignition engine according to Item 1 or 2. 4. A partition is formed so that the reverse tumble port section is located below the forward tumble port section from its upstream end to its downstream end, and the downstream end of the partition is substantially parallel to the cylinder center line. It is formed so as to be curved as described above.
Direct cylinder injection type spark ignition engine described in. 5. A first collector section communicating with the normal tumble port section of each cylinder, a second collector section communicating with the reverse tumble port section of each cylinder, and an inlet section of the first collector section as tumble adjusting means. A direct cylinder injection type spark ignition engine according to any one of claims 1 to 4, further comprising a control valve that opens and closes.