JP2002195040A - Cylinder direct-injection of fuel type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a compressed self ignition combustion area to expand on the high-load side, by delaying ignition timing at the time of compressed self ignition combustion so as to slower the pace of increase in pressure within a cylinder. SOLUTION: A fuel injection valve 10 is disposed to a cylinder wall on an intake port 6 side, a first recessed chamber 41 having a small opening area is formed in the fuel injection valve 10 side of a piston crown 4a, and a second recessed chamber 42 having a large opening area is formed near the first recessed chamber 41. Rich air-fuel mixture 52 is supplied in the first recessed chamber 41, and lean air-fuel mixture 51 is supplied in the second recessed chamber 42; and the rich air-fuel mixture 52 is burnt by spark ignition posterior to a top dead center to generate heat, and the heat causes the compressed self-ignition combustion of the lean air-fuel mixture 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-cylinder direct injection internal combustion engine, and more particularly to an engine in which compression self-ignition combustion is performed using a fuel having a low cetane number such as gasoline.

[0002]

2. Description of the Related Art Hitherto, as an internal combustion engine which performs compression self-ignition combustion, there has been one disclosed in Japanese Patent Application Laid-Open No. Hei 10-196424. This is provided with a control piston as auxiliary compression means separately from the piston in the cylinder, and further adds compression by the control piston to the air-fuel mixture which has been compressed to a high temperature just before self-ignition. Are self-ignited simultaneously.

An engine configured to cause self-ignition by spark ignition by a spark plug is disclosed in
-21039. This one is
It is determined whether or not the gas temperature in the cylinder at the end of the compression stroke is a target temperature at which ignition of the entire air-fuel mixture causes self-ignition, and the valve opening timing of the intake valve is controlled based on this determination to thereby control the compression. The gas temperature in the cylinder at the end of the stroke is maintained at the target temperature.

[0004]

By the way, the compression self-ignition combustion has an advantage that, unlike the combustion by flame propagation, the local combustion temperature is low and NOx is generated only in a very small amount. In an air-fuel mixture field, the entire area inside the cylinder is ignited all at once.Therefore, if the air-fuel mixture is enriched with an increase in load, the pressure rise rate in the cylinder will become too large, and vibration and noise will increase. is there.

Therefore, in order to expand the load region in which the compression self-ignition combustion operation is performed to the high load side, the ignition timing is set near or after the top dead center, and most of the combustion is performed after the top dead center. , It is necessary to suppress the rate of pressure increase in the cylinder. However, if the ignition timing is delayed near or after the top dead center, the initial combustion proceeds with the lowering of the piston, so that the combustion tends to be unstable, and the load for performing the compression self-ignition combustion operation. In order to expand the region to the high load side, it is necessary to delay the ignition timing and obtain stable combustion.

On the other hand, in a homogeneous gas mixture field, Japanese Patent Application Laid-Open
If the assist by the ignition plug as disclosed in Japanese Patent Application Laid-Open No. 1-210539 is applied, the ignition timing of the compression self-ignition combustion can be stabilized. However, according to the above method, even if compression self-ignition combustion occurs near or at the top dead center, the ignition timing cannot be delayed, and it is not effective in expanding the compression self-ignition combustion region to the high load side. Does not demonstrate.

Further, in the compression self-ignition combustion, a method is provided in which a rich mixture field is locally formed, self-ignition or spark ignition is performed therefrom, and the surrounding fuel is compressed and self-ignited by combustion from the rich mixture field. Are disclosed in JP-A-11-210.
No. 539. However, JP-A-11-
As disclosed in Japanese Patent Publication No. 210539, fuel is injected from a peripheral wall of a combustion chamber on a side where an intake valve is disposed toward a piston crown, and fuel spray is lifted along a wall provided on the piston crown to ignite. In the configuration where the rich mixture is collected around the plug, it is difficult to keep the rich mixture in a certain place.To stably supply the rich mixture to the ignition plug located in the center of the cylinder head, a large amount of fuel must be supplied. Even if injection must be performed and the ignition timing can be delayed near or after the top dead center, it is difficult to reduce the pressure rise rate because of the rich mixture.

[0008] The present invention has been made in view of the above problems, and by compressing and self-igniting the surrounding fuel by combustion from a rich air-fuel mixture field, it is possible to reliably suppress the pressure rise rate. Accordingly, it is an object of the present invention to provide a direct injection type internal combustion engine capable of expanding a compression self-ignition combustion region to a high load side.

[0009]

According to the present invention, a fuel injection valve is provided in a peripheral portion of a combustion chamber, and a first concave chamber is provided at an end of a piston crown surface on the side of the fuel injection valve. In addition, a second concave chamber is formed adjacent to the first concave chamber in the axial direction of the fuel injection valve.

According to this configuration, the first and second concave chambers are formed on the piston crown along the axial direction of the fuel injection valve, and the first and second concave chambers have different concentrations. (Air-fuel ratio) can be formed. According to the second aspect of the invention, the opening area of the first concave chamber on the piston crown surface is smaller than the opening area of the second concave chamber.

According to this configuration, the opening area of the first concave chamber on the side closer to the fuel injection valve is equal to the opening area of the second recess on the side farther from the fuel injection valve.
A local mixture field is formed by the first concave chamber, which is narrower than the opening area of the concave chamber, and a mixture having a different concentration is disposed in the second concave chamber having a large opening area, so that the concentration in the combustion chamber is reduced. Are stratified. According to the third aspect of the invention, the depth of the first concave chamber is smaller than the depth of the second concave chamber.

According to this configuration, the depth of the first concave chamber on the side closer to the fuel injection valve is smaller than the opening area of the second concave chamber on the side farther from the fuel injection valve, and the first concave chamber has a local area. While an air-fuel mixture field is formed, the air-fuel mixture having different concentrations is
By arranging them in the concave chamber, stratification of air-fuel mixtures having different concentrations is performed in the combustion chamber. In the invention described in claim 4, the second
The concave chamber has an arc-shaped cross section in the axial direction of the fuel injection valve, and the opening is formed in a substantially rectangular shape extending to the periphery of the piston crown surface.

According to this configuration, the bottom surface of the second concave chamber is
An arc-shaped cross section in the axial direction of the fuel injection valve,
The tumble flow caused by the intake air in the cylinder is maintained by forming the cylinder into a substantially rectangular shape that extends to the periphery of the piston crown. According to the fifth aspect of the invention, the intake port is provided with a tumble flow enhancing means for enhancing the tumble flow formed in the cylinder during the intake stroke.

According to this configuration, the tumble flow formed by the intake air in the cylinder is positively enhanced by the tumble flow enhancing means. In the invention according to claim 6, the tumble flow enhancing means is a shutoff valve that partially opens and closes an intake port, and when the shutoff valve is closed, a drift occurs in the intake air. To enhance the tumble flow.

According to this configuration, since a part of the intake port is shielded by the shut-off valve, the drift of the intake air occurs so as to enhance the tumble flow. According to the seventh aspect of the present invention, a rich air-fuel mixture is disposed in the first concave chamber, and a lean air-fuel mixture is disposed in the second concave chamber. According to this configuration, while the rich air-fuel mixture is disposed in the first concave chamber, the lean air-fuel mixture is disposed in the second concave chamber adjacent to the first concave chamber, and the rich air-fuel mixture is spark-ignited or compressed. By burning by ignition, it is possible to cause the adjacent lean air-fuel mixture to self-ignite combustion by the heat generated by the rich air-fuel mixture.

In the invention described in claim 8, the rich air-fuel mixture disposed in the first concave chamber is an air-fuel mixture leading to compression auto-ignition near the top dead center, and the rich air-fuel mixture disposed in the first concave chamber is provided. The lean air-fuel mixture disposed in the second concave chamber is brought to the compression self-ignition combustion by the compression self-ignition of the gas. According to this configuration, when the rich air-fuel mixture disposed in the first concave chamber reaches the compression self-ignition, the generated heat causes the lean air-fuel mixture disposed in the adjacent second concave chamber to perform the compression self-ignition combustion.

According to the ninth aspect of the present invention, the rich air-fuel mixture disposed in the first concave chamber is ignited by spark ignition of a spark plug to compress the lean air-fuel mixture disposed in the second concave chamber. The configuration is such that ignition combustion is achieved. According to this configuration, when the rich air-fuel mixture disposed in the first concave chamber is spark-ignited by the spark plug, the generated heat causes the lean air-fuel mixture disposed in the adjacent second concave chamber to undergo compression self-ignition combustion.

According to the tenth aspect of the present invention, fuel is injected from the fuel injection valve during the compression stroke, so that a rich air-fuel mixture is disposed in the first concave chamber and a lean mixture is supplied to the second concave chamber. Care was taken. According to such a configuration,
By injecting fuel during the compression stroke, the fuel spray collides and diffuses on the bottom surface of the first concave chamber, and a rich air-fuel mixture accumulates in the first concave chamber. Qi is formed.

According to the eleventh aspect of the present invention, fuel is injected at least twice in the same cycle, that is, fuel injection near the top dead center from the latter half of the compression stroke and fuel injection before the injection timing. Thus, a configuration is adopted in which a rich air-fuel mixture is disposed in the first concave chamber and a lean air-fuel mixture is disposed in the second concave chamber. According to this configuration, the fuel injected near the top dead center from the latter half of the compression stroke stays in the first concave chamber to form a rich air-fuel mixture, while the fuel is injected earlier than the injection timing near the top dead center from the latter half of the compression stroke. The fuel injected at the time of (1) forms a lean mixture in the second concave chamber by diffusion.

[0020]

According to the first aspect of the present invention, a mixture of different concentrations (air-fuel ratio) is disposed in the first and second concave chambers,
It is possible to stably stratify the air-fuel mixture, and in a configuration in which the adjacent lean air-fuel mixture is compressed and self-ignited by combustion from a rich air-fuel mixture field, the rich air-fuel mixture is generated only to the minimum necessary for ignition This has the effect that the combustion of most of the fuel can be delayed.

According to the second and third aspects of the present invention, there is an effect that the first concave chamber is used as a local gas-mixture formation field, so that the mixture having different concentrations can be surely stratified. According to the fourth aspect of the invention, the tumble flow due to the intake air is held by the second concave chamber, and the air-fuel mixture generated in the second concave chamber can be made uniform, and the combustion stability can be improved. effective.

According to the fifth and sixth aspects of the present invention, by enhancing the tumble flow generated by the intake air, the air-fuel mixture generated in the second concave chamber can be made uniform, and the combustion stability is improved. There is an effect that can be made. According to the seventh aspect of the invention, the lean air-fuel mixture disposed in the second concave chamber can be compressed and self-ignited by the local combustion of the rich air-fuel mixture stably disposed in the first concave chamber. , Most of the fuel can be brought to compression self-ignition combustion by the combustion of the minimum necessary rich mixture, and the compression self-ignition combustion area is expanded to the high load side by delaying the combustion of most fuel There is an effect that it becomes possible to do.

According to the present invention, the lean air-fuel mixture disposed in the adjacent second concave chamber is subjected to the compression self-ignition combustion by the compression self-ignition combustion of the rich air-fuel mixture disposed in the first concave chamber. As a result, most of the combustion is generated near or after the top dead center, the pressure rise rate can be suppressed, and the compression self-ignition combustion region can be expanded to the high load side. There is.

According to the ninth aspect of the present invention, the lean air-fuel mixture disposed in the adjacent second concave chamber is brought to the compression self-ignition combustion by the spark ignition combustion of the rich air-fuel mixture disposed in the first concave chamber. As a result, most of the combustion is generated near or after the top dead center, the rate of pressure rise can be suppressed, the compression self-ignition combustion region can be expanded to a high load side, and the first concave chamber can be formed. In this case, the self-ignition timing can be controlled within a range in which the pressure rise rate can be suppressed and the combustion stability can be ensured.

According to the tenth aspect, a rich air-fuel mixture is disposed in the first concave chamber by the injection during the compression stroke.
There is an effect that a lean air-fuel mixture can be easily arranged in the second concave chamber. According to the eleventh aspect of the present invention, the fuel is divided into two or more injections in the same cycle, and the second and subsequent fuel injections are performed near the top dead center from the latter half of the compression stroke. There is an effect that a rich air-fuel mixture can be stably formed in one concave chamber.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a direct injection gasoline engine to which the present invention is applied. In FIG. 1, a combustion chamber 2 of an engine 1 is formed by a cylinder 3, a piston 4, and a cylinder head 5.

An intake port 7 communicating with the combustion chamber 2 is provided with an intake valve 7, and an exhaust port 8 communicating with the combustion chamber 2 is also provided with an exhaust valve 9. The cylinder head 5 is formed in a pent roof type, and the intake valve 7 and the exhaust valve 9 are arranged in a V shape. A fuel injection valve 10 for injecting fuel toward the piston crown surface 4a is provided on the cylinder wall on the side of the intake port 6, and a cylinder head 5 near the fuel injection valve 10 is provided with a fuel injection valve 10 just below the fuel injection valve 10. A spark plug 11 is provided for spark ignition of the air.

A first concave chamber 41 is provided on the crown surface of the piston 4.
And the second concave chamber 42 is formed. The first concave chamber 41 includes:
The opening is formed at the end of the piston crown face on the side of the fuel injection valve 10, and the opening is formed in an elliptical shape that is short in the axial direction of the fuel injection valve 10, and the bottom is deeper toward the center. Incidentally, the opening area of the first concave chamber 41 is set so as to form a local mixed gas field near the ignition plug 11.
2 is formed much smaller than the opening area.

The second concave chamber 42 is provided in the first concave chamber 41.
Is formed adjacent to the fuel injection valve 10 in the axial direction with respect to the first concave chamber 4 from the side near the fuel injection valve 10.
The first and second concave chambers 42 are formed in this order. The opening of the second concave chamber 42 has a rectangular shape composed of a pair of sides extending along the axial direction of the fuel injection valve 10 and a pair of sides orthogonal to these sides, and is formed around the periphery of the piston crown. Formed to spread out. Then, the first concave chamber 41 and the second concave chamber 42 are formed such that the elliptical opening of the first concave chamber 41 is in contact with one side of the rectangular opening on the side of the fuel injection valve 10. Adjacent.

The bottom surface of the second chamber 42 is formed so as to have an arc-shaped cross section in the axial direction of the fuel injection valve 10, and the maximum depth is greater than the first chamber 41. Formed. An engine control unit (hereinafter referred to as ECU) 20 for controlling the injection amount / injection timing of the fuel injection valve 10 and the ignition timing of the ignition plug 11
The combustion pattern determining unit 21 determines which of the compression self-ignition combustion and the spark ignition combustion is to be operated according to the operating conditions.
0 and spark ignition combustion control unit 2 for controlling spark plug 11
2. A self-ignition combustion control unit 23 that controls the fuel injection valve 10 and the spark plug 11 during compression self-ignition combustion.

As shown in FIG. 2, the combustion pattern judging section 21 judges the combustion system based on the load of the engine and the number of revolutions N (rpm). It is determined as a self-ignition combustion region, and other high-load, high-speed regions are determined as spark-ignition combustion regions. Note that the combustion pattern determination unit 21, the spark ignition combustion control unit 22, and the self-ignition combustion control unit 23 can be constituted by a hard-wired logic circuit.
It is realized as a microcomputer program.

The flowchart of FIG.
In step S101, the load and rotation speed of the engine 1 are read. In step S102, it is determined whether or not the engine is in a low-load area within the compression-self-ignition combustion area shown in FIG. When the load is in the low load region within the compression self-ignition combustion region, the process proceeds to step S103, in which fuel injection is performed in the first half to the second half of the compression stroke.
2, a mixture 51 leaner than a stoichiometric (stoichiometric air-fuel ratio) with a high degree of stratification is generated.

Next, in step S104, fuel injection is performed at a lower flow rate than the first time in the vicinity of the top dead center from the latter half of the compression stroke. An air-fuel mixture 52 near the air-fuel ratio) is formed. Then, the rich air-fuel mixture 52 disposed in the first concave chamber 41 is burned after the top dead center by spark ignition by the ignition plug 11, and the heat generated by the combustion causes the lean mixture 52 disposed in the adjacent second concave chamber 42. The gas 51 is brought to compression self-ignition combustion.

On the other hand, when it is determined in step S102 that the region is not the low load region in the compression self-ignition combustion region,
Proceeding to step S105, it is determined whether or not the engine is in a medium load area within the compression self-ignition combustion area. When the load is in the medium load range in the compression auto-ignition combustion range, step S
Proceed to 106.

In step S106, fuel injection is performed in the intake stroke. By this first fuel injection, a mixture 51 leaner than the stoichiometric (stoichiometric air-fuel ratio) with a high stratification degree is generated in the second concave chamber 42. . Next, in step S107, fuel injection is performed at a lower flow rate than the first time near the top dead center from the latter half of the compression stroke, and the second fuel injection causes the first concave chamber 41 to stoichiometrically (stoichiometric air-fuel ratio). A rich air-fuel mixture 52 is formed in the vicinity.

Then, the rich air-fuel mixture 52 disposed in the first concave chamber 41 is burned after the top dead center by spark ignition by the ignition plug 11, and is disposed in the adjacent second concave chamber 42 by the heat generated by the combustion. The lean mixture 51 is brought to compression self-ignition combustion. If it is determined in step S105 that it is not the middle load region, it is the high load region corresponding to the spark ignition combustion region. By injecting all the fuel at once, a uniform air-fuel mixture is formed in the combustion chamber.

Then, the uniform mixture is ignited and burned by spark ignition of the spark plug 11. As described above, in the compression self-ignition combustion region, the rich air-fuel mixture 52 near the stoichiometry is burned after the top dead center by spark ignition, and the heat of the air-fuel mixture 52 causes the lean air-fuel mixture 51 to reach the compression self-ignition combustion. In the case of the tightening configuration, most of the combustion occurs in a period after the top dead center.

That is, in the case of compression self-ignition combustion in a homogeneous gas mixture field, self-ignition occurs simultaneously when the conditions of pressure and temperature are near the top dead center, and the ignition timing cannot be delayed. However, as described above, if the configuration is such that the lean air-fuel mixture 51 is brought to the compression self-ignition combustion by the heat generated by the combustion of the rich air-fuel mixture 52, the timing of the self-ignition can be delayed from the top dead center. Combustion occurs in a period after the top dead center.

As described above, if most of the combustion can be caused in a period after the top dead center, the pressure rise rate in the cylinder which causes knocking is suppressed (see FIG. 4), and the compression auto-ignition is performed. The area can be expanded to the high load side where the demand for the fuel amount increases. In addition, the temperature in the cylinder that determines the compression self-ignition timing is affected by the residual gas in the cylinder, and once the self-ignition timing is advanced, as shown in FIG. As the ignition timing increases, the ignition timing tends to be more advanced, and the combustion stability decreases as the self-ignition timing decreases.

However, as described above, if the rich mixture 52 in the vicinity of the stoichiometric fuel is burned by spark ignition so as to bring the lean mixture 51 to the compression self-ignition combustion, the self-ignition timing is set to the spark ignition. The self-ignition timing can be controlled through the timing, and as shown in FIG. 5, the self-ignition timing can be controlled within the knocking limit and within a narrow range in which the combustion stability can be ensured.

Further, the first concave chamber 41 is provided at a position close to the fuel injection valve 10 on the piston crown surface, and the second concave chamber 42 is provided adjacent to the first concave chamber 41, so that rich mixing is achieved. The air-fuel mixture 52 is arranged and retained in the first concave chamber 41, and the lean air-fuel mixture 51 is allocated to the adjacent second concave chamber 42, so that stratification of the air-fuel mixture can be easily performed. It is sufficient to supply the minimum amount of fuel that generates heat sufficient to bring about combustion to the first concave chamber 41, and the pressure rise rate can be reliably suppressed.

In the above embodiment, the first concave chamber 41
The rich air-fuel mixture 52 near the stoichiometric air (stoichiometric air-fuel ratio) is ignited by sparks. However, the rich air-fuel mixture 52 arranged in the first concave chamber 41 is compressed and self-ignited to generate heat. Thus, the lean air-fuel mixture 51 disposed in the second concave chamber 42 can be configured to be brought into compression self-ignition combustion.

Also in the above case, most of the combustion can be delayed as compared with the case where the homogeneous mixture in the combustion chamber 2 is simultaneously compressed and ignited, thereby suppressing the rate of pressure rise. However, if the rich mixture 52 arranged in the first concave chamber 41 is spark-ignited, the self-ignition timing can be further delayed, and
Since the self-ignition timing of the lean mixture 51 can be controlled, more stable self-ignition combustion can be performed.

Incidentally, in the above embodiment, the first concave chamber 4
1 shows a rich air-fuel mixture 52 near stoichiometric air-fuel ratio.
In order to distribute the air-fuel mixture 51 leaner than the stoichiometric condition in the second concave chamber 42, the fuel is divided into two injections in the same cycle. However, one injection during the compression stroke is performed. It is also possible to generate the air-fuel mixtures 51 and 52 only by using the air-fuel mixture.

That is, when fuel is injected during the compression stroke, the fuel spray collides with the bottom surface of the first concave chamber 41 and diffuses, and the rich air-fuel mixture 52 accumulates in the first concave chamber 41 while the adjacent second air-fuel mixture 52 accumulates.
A lean mixture 51 is generated in the concave chamber 42 side. However,
When the fuel is divided into two injections, it is possible to stably form a mixture with a high degree of stratification. In addition, the fuel injection angle of each of the two injections is set to one of the first and second concave chambers. By making them different depending on whether they are supplied, it is possible to form a mixture with a higher stratification degree.

As shown in FIG. 6, by enhancing the tumble flow (arrow A in FIG. 1) generated in the cylinder during the intake stroke, the lean air-fuel mixture 51 generated in the second concave chamber 42 is increased. And the diffusion of the fuel disposed in the second concave chamber 42 can be suppressed, and the combustion stability of the lean mixture 51 can be improved. Therefore, in this embodiment, the intake port 6 is a straight port, and the combustion chamber 2
The shape is such that a tumble flow is easily generated inside.

The opening of the second concave chamber 42 is a rectangular opening extending to the periphery of the piston crown surface, and the bottom surface is formed in an arc shape along the tumble flow. The tumble flow is maintained. Further, a shielding valve 61 that shields substantially half of the intake port 6 on the side close to the cylinder wall is interposed, and by closing the shielding valve 61, a drift of intake air that enhances the tumble flow is generated. It is.

If the tumble flow enhancing means for positively enhancing the tumble flow like the above-mentioned shutoff valve 61 is provided in the intake port 6, the lean mixture 51 generated in the second concave chamber 42 can be made uniform. Further, the diffusion of the fuel disposed in the second concave chamber 42 can be suppressed more reliably, and the stability of the self-ignition combustion can be further improved. In each of the above embodiments, the shape of the cylinder head 5 is a pent roof, but may be, for example, a flat shape, and the shape of the cylinder head 5 is not limited.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an internal combustion engine according to an embodiment.

FIG. 2 is a diagram showing a self-ignition combustion region and a spark ignition combustion region in the embodiment.

FIG. 3 is a flowchart showing a state of fuel injection control in the embodiment.

FIG. 4 is a diagram showing a correlation between a compression self-ignition timing, a pressure, and an amount of generated heat.

FIG. 5 is a diagram showing a correlation between compression self-ignition timing, knock strength, and combustion stability.

FIG. 6 is a diagram showing a correlation between the intensity of the tumble flow and the combustion stability.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Combustion chamber 3 ... Cylinder 4 ... Piston 4a ... Crown surface 5 ... Cylinder head 6 ... Intake port 7 ... Intake valve 8 ... Exhaust port 9 ... Exhaust valve 10 ... Fuel injection valve 11 ... Spark plug 20 ... Engine Control unit (ECU) 21: combustion pattern determination unit 22: spark ignition combustion control unit 23: self-ignition combustion control unit 41: first concave chamber 42: second concave chamber 51: lean mixture 52: rich mixture 61: shielding valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F02D 41/02 351 F02D 41/02 351 380 380G 41/38 41/38 B 41/40 41/40 D F02F 3/26 F02F 3/26 C B

Claims (11)

[Claims] 1. A fuel injection valve is provided at a peripheral portion of a combustion chamber, a first concave chamber is formed at an end of a piston crown on the side of the fuel injection valve, and the fuel is provided with respect to the first concave chamber. An in-cylinder direct injection internal combustion engine, wherein a second concave chamber is formed adjacent to the injection valve in the axial direction. 2. An in-cylinder direct injection internal combustion engine according to claim 1, wherein an opening area of said first concave chamber in a piston crown surface is smaller than an opening area of said second concave chamber. 3. The direct injection internal combustion engine according to claim 1, wherein a depth of said first concave chamber is smaller than a depth of said second concave chamber. 4. The fuel injection valve according to claim 4, wherein the second concave chamber has an arc-shaped cross section in the axial direction of the fuel injection valve, and the opening is formed in a substantially rectangular shape extending to a peripheral portion of the piston crown surface. An in-cylinder direct injection internal combustion engine according to any one of claims 1 to 3. 5. The cylinder direct in cylinder according to claim 1, further comprising a tumble flow enhancing means for enhancing a tumble flow formed in the cylinder during an intake stroke in the intake port. Injection type internal combustion engine. 6. The tumble flow enhancing means is a shut-off valve that partially opens and closes an intake port. When the shut-off valve is closed, a drift occurs in intake air, and a tumble flow formed in a cylinder during an intake stroke. 6. The method according to claim 5, wherein
An in-cylinder direct injection internal combustion engine. 7. The air conditioner according to claim 1, wherein a rich air-fuel mixture is disposed in the first concave chamber, and a lean air-fuel mixture is disposed in the second concave chamber. In-cylinder direct injection internal combustion engine. 8. A rich air-fuel mixture disposed in the first recessed chamber is a fuel-air mixture which leads to compression self-ignition near the top dead center, and is provided by the compression self-ignition of the rich air-fuel mixture disposed in the first recessed chamber. 8. The direct injection internal combustion engine according to claim 7, wherein a lean air-fuel mixture disposed in said second concave chamber is brought to compression self-ignition combustion. 9. A lean fuel-air mixture disposed in the second concave chamber is brought to compression self-ignition combustion by igniting a rich air-fuel mixture disposed in the first concave chamber by spark ignition of a spark plug. The direct injection internal combustion engine according to claim 7, characterized in that: 10. A method for distributing a rich air-fuel mixture in the first concave chamber and distributing a lean air-fuel mixture in the second concave chamber by injecting fuel from the fuel injection valve during a compression stroke. An in-cylinder direct injection internal combustion engine according to any one of claims 7 to 9, wherein: 11. In the same cycle, the fuel is injected at least twice in the second half of the compression stroke, that is, fuel injection near the top dead center and fuel injection prior to the injection timing, whereby the first fuel injection is performed. The direct injection internal combustion engine according to any one of claims 7 to 9, wherein a rich air-fuel mixture is disposed in the concave chamber, and a lean air-fuel mixture is disposed in the second concave chamber. .