JP2000161067A - Direct injection type spark ignition engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve stratified combustion performance of a direct injection type spark ignition engine. SOLUTION: A sub-port 9 arranged between and along two intake ports 2a and 2b, a control valve 10 cutting-off the two intake ports are arranged, and in the intake port 2a, a flow outlet port 9a from the sub-port 9 is arranged so as to be perpendicular to the fuel injection direction and face outside. This constitution forms an orthogonal tumble flow comprising the normal tumble flow moving toward the crown face of a piston from the intake valve side through the exhaust valve side turned at 90 deg. around the center axis of an ignition plug. Through this constitution, concentrated air-fuel mixture gathers and stagnates near an ignition plug when ignited, which provide excellent (stratified) combustion without scattering spraying (uniform spray distance and proper spray angle) to enable stable ignition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spark ignition type internal combustion engine in which fuel is directly injected into a combustion chamber, and more particularly to a technique for stabilizing the combustibility during stratified combustion.

[0002]

2. Description of the Related Art Conventionally, in a direct injection type spark ignition engine in which fuel is injected directly from a fuel injection valve into a combustion chamber to form an air-fuel mixture, and is ignited by an ignition plug to perform stratified combustion, the fuel injection valve is used for injection. The axial direction is arranged substantially along the cylinder radial direction, and a plurality of spark plugs are arranged apart from each other along the injection axis direction of the fuel injection valve. There is one in which the air-fuel mixture is ignited by an ignition plug close to the valve, and the air-fuel mixture is ignited by an ignition plug far from the fuel injection valve as the engine speed increases.
Thus, the stratified combustion region is expanded to improve fuel efficiency (see Japanese Patent Application Laid-Open No. 10-169446).
.

[0003]

However, in such a conventional direct injection type spark ignition engine, the fuel injection period depends on the gas flow strength, back pressure, etc. depending on the operating conditions.
The ignition chance is determined from the relationship between the shape of the fuel spray and the position of the spark plug. For this reason, although the aim is to increase ignition chances by changing the ignition system and improve combustion stability under each condition, cycle fluctuations in stability due to variations in the fuel spray shape and the rich mixture distribution The deterioration cannot be prevented. That is, since the demand for spraying is very high, the robustness with respect to combustion stability is extremely low.

The present invention has been made in view of such a conventional problem, and has a structure in which a rich air-fuel mixture is caused to flow intensively in the vicinity of a spark plug in a combustion chamber. It is an object of the present invention to provide a direct injection spark ignition engine that solves the problem.

[0005]

According to the present invention, a fuel injection valve directly injects fuel obliquely downward from a fuel injection valve to a combustion chamber, and an ignition plug disposed substantially at the center of the combustion chamber. In the direct injection type spark ignition engine that performs stratified combustion by igniting at the right angle, the orthogonal tumble flow is obtained by rotating the forward tumble flow from the intake valve side to the piston crown surface through the exhaust valve side by about 90 ° about the center axis of the spark plug. Is provided, a fuel injection valve is disposed so that the injected fuel is directed to the vortex center of the orthogonal tumble flow, and a squish flow toward the center of the combustion chamber is generated by raising the piston. A squish flow generating means is provided.

According to the first aspect of the invention, the orthogonal tumble flow generating means generates the orthogonal tumble flow obtained by rotating the forward tumble flow by approximately 90 ° about the center axis of the spark plug, and the vortex center of the orthogonal tumble flow. Is injected into the fuel. Thereby, during fuel injection, the air-fuel mixture is wrapped in the orthogonal tumble flow regardless of the fuel spray shape, so that the fuel does not adhere to the peripheral portion of the combustion chamber (the upper surface of the combustion chamber, the piston crown surface, the cylinder side surface, etc.). The air-fuel mixture is distributed in the center of the combustion chamber, and then, as it approaches the top dead center, the squish flow generated by the squish flow generation means toward the center of the combustion chamber reduces the orthogonal tumble flow to the center of the combustion chamber. Go. Therefore, at the time of ignition, the rich air-fuel mixture concentrates and stagnates in the vicinity of the spark plug 5, so that the ignition can be stably performed irrespective of the variation of the spray shape (spray penetration distance, spray angle, etc.), and good combustion can be achieved. (Stratified combustion) is performed.

According to a second aspect of the present invention, the orthogonal tumble flow generating means includes a sub port disposed between the two intake ports, a control valve for shutting off the two intake ports, and one intake port. An outlet from the subport is arranged in the port so as to be perpendicular to the fuel injection direction and to face outward.

According to the second aspect of the invention, for example, when the operating condition of the engine is in the stratified charge combustion region, by closing the control valve, the intake air flowing from the subport flows from one intake valve to the lower part of the combustion chamber. A vertical vortex, which is directed toward the piston crown surface and toward the other intake valve, generates an orthogonal tumble flow obtained by rotating the forward tumble flow by approximately 90 ° about the center axis of the ignition plug 5. When the operating condition of the engine is in the homogeneous combustion region, by opening the control valve,
The intake air flows in from the intake port, and generates a forward tumble flow from the intake valve side to the exhaust valve side, and further from the upper side of the combustion chamber on the exhaust valve side to the piston crown surface side.

According to a third aspect of the present invention, the orthogonal tumble flow generating means includes an arc-shaped concave portion provided on a piston crown surface in parallel with a flow direction of the orthogonal tumble flow, and the squish flow is provided. The generation means is characterized by being constituted by a squish generation surface formed in parallel with the combustion chamber upper surface shape around the concave portion of the piston crown surface.

According to the third aspect of the present invention, the orthogonal tumble flow is induced by the arc-shaped concave portion of the piston crown surface, so that a more stable tumble flow can be generated. A squish flow toward the center of the combustion chamber can be generated.

The invention according to claim 4 is characterized in that the spark plug is
It is characterized in that the piston is projected to approximately half the depth of the recess provided in the piston.

According to the present invention, at the time of ignition (near top dead center) during stratified charge combustion or the like, the squish flow is applied to the approximate center of the rich mixture wrapped in the orthogonal tumble flow reduced to the center of the combustion chamber. Since the spark plug is located, ignition can be performed more stably.

According to a fifth aspect of the present invention, there is provided a combustion chamber formed at an upper portion of a piston, and a fuel injection valve at a lower portion of an intake port for directly injecting fuel obliquely downward to the combustion chamber,
In a direct injection type spark ignition engine in which stratified combustion is performed by igniting with an ignition plug disposed substantially at the center of the combustion chamber, two forward tumble flows are rotated by approximately 90 ° about the ignition plug central axis, respectively. Orthogonal tumble flow generating means for generating two orthogonal tumble flows, a fuel injection valve disposed so that the injected fuel is directed toward the center of the two orthogonal tumble flows, and toward the center of the combustion chamber when the piston rises A squish flow generating means for generating a squish flow is provided.

According to the fifth aspect of the invention, the orthogonal tumble flow generating means generates two orthogonal tumble flows obtained by rotating the two forward tumble flows by approximately 90 ° about the center axis of the spark plug. Fuel is injected at the vortex center of the orthogonal tumble flow. Thereby, during fuel injection, the air-fuel mixture is wrapped in the orthogonal tumble flow regardless of the fuel spray shape, so that the fuel does not adhere to the peripheral portion of the combustion chamber (the upper surface of the combustion chamber, the piston crown surface, the cylinder side surface, etc.). The mixture is distributed in the center of the combustion chamber. Further, at the center of the two orthogonal tumble flows, the air-fuel mixture flows from the piston crown surface toward the spark plug, and then, as it approaches the top dead center, due to the squish flow generated by the squish flow generation means toward the center of the combustion chamber, The two orthogonal tumble flows are reduced toward the center of the combustion chamber, and at the time of ignition, the rich mixture is concentrated toward the ignition plug, so that regardless of the variation in the spray shape (spray penetration distance, spray angle, etc.) The ignition can be performed stably, and good combustion (stratified combustion) is performed.

The invention according to claim 6 is characterized in that the fuel injection valve is arranged so as to inject fuel toward two vortex centers of two orthogonal tumble flows with two fuel injection directions. And

According to the sixth aspect of the present invention, since the fuel is respectively injected toward the vortex centers of the two orthogonal tumble flows, during the fuel injection, the air-fuel mixture is reduced by two regardless of the fuel spray shape.
The air-fuel mixture is wrapped in two orthogonal tumble flows, and the fuel-air mixture is distributed in the central part of the combustion chamber without the fuel adhering to the peripheral part of the combustion chamber (the upper surface of the combustion chamber, the piston crown, the side of the cylinder, etc.). Thereafter, as approaching the top dead center, the two orthogonal tumble flows are reduced toward the center of the combustion chamber due to the squish flow toward the center of the combustion chamber. Therefore, at the time of ignition, the rich mixture is concentrated toward the spark plug. As a result, the ignition can be stably performed irrespective of variations in the spray shape (spray penetration distance, spray angle, etc.), and good stratified combustion is performed.

According to a seventh aspect of the present invention, the orthogonal tumble flow generating means includes a sub port disposed at a central portion between the two intake ports, a control valve for shutting off a main intake port, and two intake ports. An outlet from the subport is arranged in the port so as to be perpendicular to the fuel injection direction and to face outward.

According to the seventh aspect of the present invention, for example, when the operating condition of the engine is in the stratified charge combustion region, by closing the control valve, the intake air flowing from the sub-port is supplied from the two intake valves to the piston crown surface below the combustion chamber. To generate two longitudinal vortices in the direction between the two intake valves (the center line of the combustion chamber), that is, two orthogonal tumble flows.

According to an eighth aspect of the present invention, the orthogonal tumble flow generating means is configured to include two arc-shaped concave portions provided on the piston crown surface in parallel with the two orthogonal tumble flow directions. The squish flow generation means is constituted by a squish flow generation surface formed around the concave shape and parallel to the combustion chamber upper surface shape.

According to the eighth aspect of the present invention, two orthogonal tumble flows are induced in the arc-shaped concave portion of the crown surface of the piston, so that a more stable tumble flow can be generated, and the piston position is at the top dead center. In the vicinity, a squish flow toward the center of the combustion chamber can be reliably generated.

According to a ninth aspect of the present invention, an ignition plug is provided,
It is characterized in that the piston is projected to approximately half the depth of the recess provided in the piston.

According to the ninth aspect of the present invention, at the time of ignition (near top dead center) such as during stratified charge combustion, the squish flow is applied to the approximate center of the rich mixture wrapped in the orthogonal tumble flow reduced to the center of the combustion chamber. Since the spark plug is located, ignition can be performed more stably.

According to a tenth aspect of the present invention, two ignition plugs are disposed substantially at the center of the two concave portions, or an ignition plug having two electrodes is connected to the two concave portions. Characterized by being arranged substantially at the center.

According to the tenth aspect of the present invention, at the time of ignition (near top dead center) during stratified charge combustion, etc., the squish flow causes the two rich mixtures wrapped in the orthogonal tumble flow reduced in the center of the combustion chamber. The ignition is performed at the center, and the stability is further improved.

[0025]

FIG. 1 shows a first embodiment of the present invention. In the figure, a direct injection spark ignition engine 1
Fuel is directly injected obliquely downward into a combustion chamber 4 from a fuel injection valve 3 provided at a lower portion of the intake port 2 (2a, 2b).
The fuel is ignited by an ignition plug 5 disposed substantially at the center of the combustion chamber 4 to perform stratified combustion.

In the direct-injection spark ignition engine 1 having such a configuration, the forward tumble flow from the intake valve 6 side to the exhaust valve 7 side, and further from the upper surface of the combustion chamber 4 on the exhaust valve 7 side to the piston 8 crown surface side, An orthogonal tumble flow generating means for generating an orthogonal tumble flow obtained by rotating the forward tumble flow by approximately 90 ° about the center axis of the ignition plug 5 is provided. Specifically, as shown in detail in FIG. 2, a sub-port 9 is provided between the two intake ports 2a and 2b by drilling, and a control valve 10 for shutting off the intake ports 2a and 2b is provided. The outlet 9a from the sub-port 9 is disposed in the intake port 2a of the first fuel injection port 2a so as to be directed perpendicularly and outwardly to the fuel injection direction.

Thus, when the operating condition of the engine is in the stratified combustion region, the control valve 10 is closed,
The intake air flowing from the sub port 9 is supplied to the intake valve 6a on one side.
, A vertical vortex flowing toward the piston 8 below the combustion chamber 4 and toward the other intake valve 6b, that is, an orthogonal tumble flow T1 obtained by rotating the forward tumble flow by approximately 90 ° about the center axis of the ignition plug 5. Generate When the operating condition of the engine is in the homogeneous combustion region, by opening the control valve 10, the intake air flows in from the main intake port 2, the intake valve 6 side to the exhaust valve 7 side, and further the exhaust valve. 7 side combustion chamber 4
Forward tumble flow T2 from upper surface to piston 8 crown surface side
Generate

Further, a squish flow generating means for generating a squish flow S toward the combustion chamber 4 is provided. Specifically, the peripheral edge of the crown surface of the piston 8 is formed on a squish flow generation surface 8 a parallel to the upper surface of the combustion chamber 4. As the engine operating conditions detected for switching between the orthogonal tumble flow T1 and the forward tumble flow T2 by the control valve 10, the load is detected by the accelerator opening sensor 11, and the engine rotation speed is detected by the crank angle sensor 12. , These detection signals are input to the control unit 13. The control unit 13 controls opening and closing of the control valve 10 via an actuator 14 in accordance with operating conditions of the engine, and also controls fuel injection amount, injection timing, ignition timing, and the like.

Next, the operation will be described. In the stratified combustion region (see FIG. 3) where the operating conditions detected by the engine load, the rotational speed, and the like, the fuel is injected in the compression stroke as shown in FIG. 4, and the fuel is injected into the vortex center of the orthogonal tumble flow T1. Therefore, during fuel injection, the air-fuel mixture M
Is wrapped in the orthogonal tumble flow T1, so that the fuel mixture does not adhere to the peripheral portion of the combustion chamber 4 (the upper surface of the combustion chamber, the piston crown surface, the side surface of the cylinder, etc.), and the mixture M is distributed in the center of the combustion chamber 4. . Thereafter, as shown in FIG. 5, as the vehicle approaches the top dead center, the squish flow S generated by the squish flow generation surface 8a toward the center of the combustion chamber 4 causes the orthogonal tumble flow T1 to be reduced to the center of the combustion chamber 4. . Therefore, during ignition, the rich mixture M near the spark plug 5
Is concentrated and stagnated, and stable ignition can be performed irrespective of variations in spray shape (spray penetration distance, spray angle, etc.), and good stratified combustion is performed.

When the operating condition of the engine is homogeneous combustion, as shown in FIG. 6, fuel is injected in the intake stroke, the control valve 10 is opened to generate a forward tumble flow T2, and the forward tumble flow T2 is generated. By generating a homogeneous mixture with the tumble flow T2, good homogeneous combustion is performed.

FIG. 7 shows a second embodiment. In the present embodiment, as a means for strengthening and stabilizing the orthogonal tumble flow T1 in the first embodiment, the piston 8
An arcuate concave portion 8b is provided in the crown surface portion in parallel with the flow direction of the orthogonal tumble flow T1. As means for generating a squish flow S toward the center of the combustion chamber 4, the combustion chamber 4 is provided around the concave portion 8b. Squish generation surface 8 parallel to top surface shape
a is provided.

As a result, the orthogonal tumble flow T1 is induced by the arc-shaped concave portion 8b on the piston crown surface, and a more stable tumble flow can be generated. A squish flow S toward the center can be generated.

FIG. 8 shows a third embodiment. This embodiment is different from the second embodiment in that the ignition plug 5 is protruded to approximately 1/2 of the depth L of the recess 8b.

Thus, at the time of ignition during stratified charge combustion (near top dead center), the squish flow S causes the ignition plug 5 to be substantially at the center of the rich mixture M wrapped in the orthogonal tumble flow T1 reduced to the center of the combustion chamber 4. Is located, and ignition can be performed more stably.

FIG. 9 shows a fourth embodiment. The present embodiment is directed to a direct injection type spark ignition engine in which two intake ports 2a and 2b, a fuel injection valve 3 and a spark plug 5 are similarly arranged to perform stratified combustion, and two fuel injection valves are arranged from two intake valves 6a and 6b side. Two exhaust valves 7a, 7b, and further exhaust valves 7a, 7b
For each of the two forward tumble flows T21 and T22 from the upper surface of the combustion chamber 4 toward the crown 8 of the piston 8, the forward tumble flows T21 and T22 are rotated by approximately 90 ° about the central axis of the spark plug 5 to obtain two intake air flows. Between valves 2a and 2b (center of combustion chamber)
Orthogonal tumble flows T11, T going outward from
12 is provided. Specifically, the outlet of the subport 9 formed in the same manner as in the above embodiment is formed by branching into two branches, and the outlets 9a and 9b inserted into the two intake ports 2a and 2b are respectively connected to the fuel injection direction. Are provided so as to be perpendicular to the outside and to face outward. Accordingly, when the operating condition of the engine is in the stratified charge combustion region, by closing the control valve 10, the intake air flowing from the subport 9 flows from each of the intake valves 2 a and 2 b toward the crown surface of the piston 8 below the combustion chamber 4, Between two intake valves 2a and 2b (combustion chamber center line)
Two vertical vortices in the direction, ie two orthogonal tumble flows 2
2a and 22b are generated. Then, as shown in FIG. 10 (C), the configuration is such that the injected fuel 8 is directed toward the center of the two tumble flows 22a and 22b. When the operating condition of the engine is in the homogeneous combustion region, by opening the control valve 10, the intake air flows in from the main intake ports 2a, 2b, and forms forward tumble flows T21, T22. In addition,
A squish flow generating surface 8a is similarly provided on the periphery of the piston 8.

As a result, as shown in FIG.
In the stratified combustion region where the engine is operating, fuel is injected in the compression stroke and fuel is injected toward the center of the two orthogonal tumble flows T11 and T12. Is wrapped in the orthogonal tumble flows T11 and T12, so that the fuel mixture does not adhere to the peripheral portion of the combustion chamber 4 (the upper surface of the combustion chamber, the piston crown surface, the cylinder side surface, etc.), and the air-fuel mixture M Distribute. Also, 2
At the center of the two orthogonal tumble flows T11 and T12, the air-fuel mixture M flows from the crown of the piston 8 toward the spark plug 5. Thereafter, as shown in FIG. 10 (B), the two orthogonal tumble flows T11 and T12 are generated by the squish flow S toward the center of the combustion chamber 4 generated by the squish flow generation surface 8a as approaching the top dead center. At the time of ignition, the rich mixture M concentrates toward the ignition plug 5, and the ignition can be stably performed regardless of the variation of the spray shape (spray penetration distance, spray angle, etc.). , Good stratified combustion is performed.

When the operating condition of the engine is homogeneous combustion, fuel is injected in the intake stroke, the control valve 10 is opened to generate forward tumble flows T21 and T22, and the forward tumble flows T21 and T22 are generated by the ignition timing. , T22, a homogeneous air-fuel mixture is produced, whereby good homogeneous combustion is performed.

FIG. 11 shows a fifth embodiment. In the present embodiment, in the fourth embodiment, a fuel injection valve 3 capable of directing fuel in two directions is used, and fuel is injected toward the vortex centers of the orthogonal tumble flows T11 and T12, respectively. The fuel injection valve 3 is arranged so as to perform the above operation.

Thus, in the stratified combustion region where the engine is operating, fuel is injected in the compression stroke and fuel is injected into the vortex center of the two orthogonal tumble flows T11 and T12. Irrespective of the above, the surrounding portion of the combustion chamber 4 (the upper surface of the combustion chamber, the piston crown surface, the cylinder side surface, etc.) to wrap the air-fuel mixture M in the orthogonal tumble flows T11 and T12.
The air-fuel mixture M is distributed in the center of the combustion chamber 4 without fuel adhering to the fuel cell. Thereafter, as approaching the top dead center, the squish flow S generated by the squish flow generation surface 8a toward the center of the combustion chamber 4 causes two orthogonal tumble flows T11, T11,
T12 is reduced to the center of the combustion chamber 4, so that at the time of ignition, the rich mixture M is concentrated toward the spark plug 5,
As a result, the ignition can be stably performed irrespective of variations in the spray shape (spray penetration distance, spray angle, etc.), and good stratified combustion is performed.

When the operating condition of the engine is homogeneous combustion, good homogeneous combustion is performed in the same manner as in the fourth embodiment. FIG. 12 shows a sixth embodiment.

In this embodiment, the means for strengthening and stabilizing the orthogonal tumble flows T11 and T12 is different from the fourth and fifth embodiments in that
Two arc-shaped concave portions 8c and 8d are provided in parallel with the flow directions of the two orthogonal tumble flows T11 and T12. As means for generating a squish flow S toward the center of the combustion chamber 4, the combustion chamber 4 is provided around the concave portion 21. A squish generation surface 8a parallel to the top surface shape is provided.

As a result, two orthogonal tumble flows T11 and T12 are induced by the arc-shaped concave portions 8c and 8d on the piston crown surface, so that a more stable tumble flow can be generated, and when the piston 8 is located near the top dead center. , Surely combustion chamber 4
A squish flow S toward the center can be generated.

FIG. 13 shows a seventh embodiment. This embodiment is different from the fifth embodiment in that the ignition plug 5 is protruded to approximately half the depth L 'of the recesses 8c and 8d.

Thus, at the time of ignition in stratified charge combustion (near top dead center), the squish flow S ignites substantially the center of the rich mixture M wrapped in the orthogonal tumble flows T11 and T12 reduced to the center of the combustion chamber 4. Since the plug 5 is located, ignition can be performed more stably.

FIG. 14 shows an eighth embodiment. This embodiment is different from the fifth embodiment in that two ignition plugs 5
a, 4b provided substantially at the center of the two concave portions 8b, 8c of the piston 8 (A), or an ignition plug 21 having two electrodes is disposed, and the two electrodes 21a, 21b are respectively connected to two.
Provided substantially toward the center of the two recesses 8b and 8c (B)
It is.

As a result, at the time of ignition during stratified combustion (near top dead center), the squish flow S causes the two rich mixtures Ma, Mb wrapped in the orthogonal tumble flows T11, T12 reduced around the combustion chamber 4 to form a mixture. The ignition is performed substantially at the center, and the stability is further improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a direct injection spark ignition engine according to a first embodiment of the present invention and a transverse sectional view of a combustion chamber.

FIG. 2 is a longitudinal sectional view of a main part and a sectional view taken along CC of the embodiment.

FIG. 3 is a diagram showing a stratified combustion region and a homogeneous combustion region corresponding to operating conditions of the engine.

FIG. 4 is a diagram showing a state at the time of fuel injection of the embodiment.

FIG. 5 is a diagram showing a state at the time of compression top dead center in the embodiment.

FIG. 6 is a diagram showing a state at the time of homogeneous combustion in the embodiment.

FIG. 7 is a diagram showing a main part of the second embodiment.

FIG. 8 is a diagram showing a main part of the third embodiment.

FIG. 9 is a diagram showing a main part of a fourth embodiment.

FIG. 10 is a diagram illustrating a state at the time of fuel injection and near a top dead center according to a fourth embodiment.

FIG. 11 is a diagram illustrating a main part of a fifth embodiment.

FIG. 12 is a diagram illustrating a main part of a sixth embodiment.

FIG. 13 is a diagram illustrating a main part of a seventh embodiment.

FIG. 14 is a diagram showing a main part of the eighth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Direct injection spark ignition engine 2 Intake port 3 Fuel injection valve 4 Combustion chamber 5, 5a, 5b Spark plug 6 Intake valve 7 Exhaust valve 8 Piston 8a Squish generation surface 8b, 8c, 8d Recess 9 Subport 9a, 9b Outflow 10 Control valve 11 Accelerator opening sensor 12 Crank angle sensor 13 Control unit 14 Actuator 21a, 21b Electrodes T1, T11, T12 Orthogonal tumble flow T2 Forward tumble flow S Squish flow

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuyuki Ito 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term in Nissan Motor Co., Ltd. (reference) 3G023 AA01 AA18 AB03 AC05 AD03 AD05 AD07 AD08 AD09 AG01

Claims (10)

[Claims] 1. A direct injection type spark ignition engine in which fuel is injected directly obliquely downward from a fuel injection valve into a combustion chamber and stratified combustion is performed by igniting with a spark plug disposed substantially at the center of the combustion chamber. An orthogonal tumble flow generating means for generating an orthogonal tumble flow obtained by rotating a forward tumble flow from the intake valve side to the piston crown surface through the exhaust valve side by approximately 90 ° about the spark plug central axis; Direct injection type wherein a fuel injection valve is arranged so that the injected fuel is directed to the center of the vortex, and squish flow generating means for generating a squish flow toward the center of the combustion chamber by raising the piston is provided. Spark ignition engine. 2. The orthogonal tumble flow generating means includes a subport disposed along two intake ports, a control valve for shutting off the two intake ports, and an outlet from the subport to one intake port. The direct-injection spark ignition engine according to claim 1, wherein the direct-injection-type spark ignition engine is disposed so as to be perpendicular to the fuel injection direction and outward. 3. The orthogonal tumble flow generating means includes an arc-shaped concave portion provided on a piston crown surface in parallel with the flow direction of the orthogonal tumble flow, and the squish flow generating means includes a piston crown surface. 3. The direct injection spark ignition engine according to claim 1, wherein a squish generating surface formed in parallel with a combustion chamber upper surface shape is formed around the concave portion. 4. The direct-injection spark ignition engine according to claim 3, wherein the spark plug protrudes to approximately half the depth of the recess provided in the piston. 5. A combustion chamber formed at an upper portion of a piston, and a fuel injection valve provided at a lower portion of an intake port for directly injecting fuel obliquely downward to the combustion chamber, and an ignition plug disposed substantially at the center of the combustion chamber. A direct injection type spark ignition engine that performs stratified combustion by igniting at a right angle is provided with orthogonal tumble flow generating means for generating two orthogonal tumble flows obtained by rotating two forward tumble flows by approximately 90 ° around a spark plug central axis. A fuel injection valve is disposed so that the injected fuel is directed toward the center of the two orthogonal tumble flows, and squish flow generating means is provided for generating a squish flow toward the center of the combustion chamber when the piston is raised. A direct-injection spark ignition engine. 6. The fuel injection valve according to claim 5, wherein the fuel injection direction is set to two directions, and the fuel injection valve is arranged so as to inject fuel toward the vortex centers of the two orthogonal tumble flows.
A direct-injection spark ignition engine according to item 1. 7. The orthogonal tumble flow generating means includes a sub port disposed at a central portion between two intake ports, a control valve for shutting off a main intake port, and an outlet from the sub port to two intake ports. 7. The direct-injection spark ignition engine according to claim 5, wherein the fuel injection direction is arranged perpendicular to the fuel injection direction and directed outward. 8. The orthogonal tumble flow generating means includes two orthogonal tumble flows parallel to the flow directions of the two orthogonal tumble flows on the piston crown surface.
And the squish flow generating means is provided around the concave shape,
8. A squish flow generating surface formed in parallel with the shape of the upper surface of the combustion chamber.
A direct injection spark ignition engine according to any one of the preceding claims. 9. The direct injection according to claim 5, wherein the spark plug protrudes to approximately half the depth of the concave portion provided in the piston. -Type spark ignition engine. 10. The ignition plug is disposed substantially at the center of the two recesses, or the ignition plug having two electrodes is disposed such that the two electrodes face the center of the two depressions, respectively. The direct injection type spark ignition engine according to any one of claims 5 to 9, characterized in that: