JP2007327464A - Direct injection type spark ignition internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct injection type spark ignition internal combustion engine capable of surely maintaining a tumble flow up to the latter half of a compression stroke, without causing an intake shortage, in homogeneous combustion. <P>SOLUTION: This direct injection type spark ignition internal combustion engine has at least two first fuel injection valve 1 and second fuel injection valve 2 for directly injecting fuel into a cylinder. In the homogeneous combustion, the tumble flow T turning in the vertical direction in the cylinder by lowering along the exhaust valve side of a cylinder bore, is strengthened by the fuel injected in the vicinity of the intake bottom dead center by at least the two first fuel injection valve and second fuel injection valve. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a direct injection spark ignition internal combustion engine.

  In homogeneous combustion in which a homogeneous mixture is formed in the cylinder and this homogeneous mixture is ignited and combusted at the ignition timing at the end of the compression stroke, a tumble flow is formed in the cylinder by the intake air supplied into the cylinder, and this tumble flow is If the turbulence caused by the tumble flow can exist in the cylinder at the ignition timing by maintaining the second half of the compression stroke, the combustion speed of the homogeneous mixture increases due to the turbulence, and good homogeneous combustion can be realized.

  In order to maintain the tumble flow until the ignition timing at the end of the compression stroke, an intake flow control valve is arranged in the intake port, and by this intake flow control valve, intake air is supplied into the cylinder along the upper wall of the intake port. An in-cylinder injection spark ignition internal combustion engine that forms a strong tumble flow in a cylinder has been proposed (see, for example, Patent Document 1).

JP 2005-180247 A JP 2003-320222 A

  In the above-described in-cylinder spark ignition internal combustion engine, when intake air is supplied into the cylinder along the upper wall of the intake port by the intake flow control valve, the intake port is throttled by the intake flow control valve. As a result, when the required intake air amount is relatively small, a strong tumble flow can be formed in the cylinder without any problem. However, when the required intake air amount is relatively large, the intake port is controlled by the intake air flow control valve. Since a shortage of intake may occur if the throttle valve is throttled, a strong tumble flow cannot be formed in the cylinder by the intake flow control valve.

  Accordingly, an object of the present invention is to provide a direct injection spark ignition internal combustion engine capable of reliably maintaining a tumble flow until the latter half of the compression stroke without causing a shortage of intake during homogeneous combustion.

  According to a first aspect of the present invention, there is provided an in-cylinder injection spark ignition internal combustion engine comprising at least two first fuel injection valves and second fuel injection valves for directly injecting fuel into a cylinder. The fuel injected by the at least two first fuel injection valves and the second fuel injection valve in the vicinity of the intake bottom dead center is a tumble flow that descends along the exhaust valve side of the cylinder bore and turns in the cylinder in the vertical direction. It is characterized by strengthening.

  The direct injection spark ignition internal combustion engine according to claim 2 of the present invention is the direct injection spark ignition internal combustion engine according to claim 1, wherein the fuel injected by the first fuel injection valve is an ignition plug. The ignition plug is inserted into the combustible mixture formed in a part of the cylinder by injecting fuel by the first fuel injection valve in the latter half of the compression stroke. The stratified charge combustion is carried out by positioning the ignition gap.

  The in-cylinder injection spark ignition internal combustion engine according to claim 3 according to the present invention is the in-cylinder injection spark ignition internal combustion engine according to claim 2, wherein the first fuel injection valve is arranged at a substantially upper center of the cylinder, The spark plug is disposed in the vicinity of the exhaust valve side of the first fuel injection valve, the second fuel injection valve is disposed on the intake valve side around the cylinder upper portion, and during the homogeneous combustion, the second fuel injection valve is In order to strengthen the tumble flow, fuel is injected toward the exhaust valve side upper part of the cylinder bore in the vicinity of the intake bottom dead center.

  According to a fourth aspect of the present invention, the direct injection spark ignition internal combustion engine according to the third aspect is the direct injection spark ignition internal combustion engine according to the third aspect, wherein the first fuel injection in the vicinity of the intake bottom dead center during homogeneous combustion. The fuel injection timings of the valve and the second fuel injection valve are different from each other.

  The in-cylinder injection spark ignition internal combustion engine according to claim 5 according to the present invention is the in-cylinder injection spark ignition internal combustion engine according to claim 2, wherein the first fuel injection valve is arranged at a substantially upper center of the cylinder, The spark plug is disposed in the vicinity of the exhaust valve side of the first fuel injection valve, the second fuel injection valve is disposed on the exhaust valve side around the upper part of the cylinder, and during the homogeneous combustion, the second fuel injection valve is In order to strengthen the tumble flow, fuel is injected toward the piston top surface along the exhaust valve side of the cylinder bore in the vicinity of the intake bottom dead center.

  A direct injection spark ignition internal combustion engine according to claim 6 of the present invention is the direct injection spark ignition internal combustion engine according to claim 1, wherein the direct injection spark ignition internal combustion engine is an intake two-valve type. In the homogeneous combustion, the fuel injected near the intake bottom dead center by the first fuel injection valve strengthens one tumble flow formed in the cylinder via the one intake valve, and the second fuel injection valve Thus, the fuel injected in the vicinity of the intake bottom dead center strengthens the other tumble flow formed in the cylinder via the other intake valve.

  According to the in-cylinder spark-ignition internal combustion engine of the first aspect of the present invention, the in-cylinder spark-ignition internal combustion engine includes at least two first fuel injection valves and second fuel injection valves that directly inject fuel into the cylinder, and is homogeneous During combustion, a tumble flow descending along the exhaust valve side of the cylinder bore and turning vertically in the cylinder is injected in the vicinity of the intake bottom dead center by at least two first fuel injection valves and second fuel injection valves. The fuel is surely strengthened. As a result, the tumble flow formed in the cylinder without restricting the intake port is so weak that it disappears by the latter half of the compression stroke, but such tumble flow is definitely strengthened, and the tumble flow is strengthened in the latter half of the compression stroke. Can be reliably maintained until a good homogeneous combustion is achieved.

  According to the direct injection spark ignition internal combustion engine according to claim 2 of the present invention, as in the direct injection spark ignition internal combustion engine according to claim 1, the tumble flow is at least two first fuel injection valves. In addition, the fuel is surely strengthened by the fuel injected in the vicinity of the intake bottom dead center by the second fuel injection valve, and good homogeneous combustion can be realized. In addition, since the fuel injected by the first fuel injection valve passes through the ignition gap of the spark plug or in the vicinity of the ignition gap, the fuel is injected by the first fuel injection valve in the latter half of the compression stroke. Thus, the ignition gap of the spark plug can be positioned in the combustible mixture formed in a part of the cylinder, and not only homogeneous combustion but also stratified combustion can be performed.

  According to the in-cylinder injection spark ignition internal combustion engine according to claim 3 of the present invention, in the in-cylinder injection spark ignition internal combustion engine according to claim 2, the first fuel injection valve is disposed substantially at the upper center of the cylinder. The spark plug is disposed in the vicinity of the exhaust valve side of the first fuel injection valve, the second fuel injection valve is disposed on the intake valve side around the upper part of the cylinder, and the second fuel injection valve enhances the tumble flow during homogeneous combustion. Therefore, fuel is injected toward the exhaust valve side upper part of the cylinder bore in the vicinity of the intake bottom dead center. Accordingly, the tumble flow is strengthened by the fuel injected near the intake bottom dead center by the second fuel injection valve, and the first fuel injection valve is injected so as to pass through or near the ignition gap of the spark plug. The fuel in the vicinity of the intake bottom dead center can be injected obliquely downward toward the exhaust valve side of the cylinder bore to strengthen the tumble flow, and is similar to the direct injection spark ignition internal combustion engine according to claim 2. An effect can be obtained.

  According to the in-cylinder injection spark ignition internal combustion engine according to claim 4 of the present invention, in the in-cylinder injection spark ignition internal combustion engine according to claim 3, the first fuel in the vicinity of the intake bottom dead center during homogeneous combustion. The fuel injection timings of the injection valve and the second fuel injection valve are made different from each other. When the fuel injection timings of the first fuel injection valve and the second fuel injection valve coincide with each other and the two injected fuels merge, an air vortex is generated near the upper part of the cylinder bore on the exhaust valve side as the merged injected fuel moves. The air vortex may collide with the tumble flow in the latter half of the compression stroke. In this case, since the tumble flow strengthened by the injected fuel is weakened, the first fuel injection valve and the second Generation of such air vortices is suppressed by making the fuel injection timings of the fuel injection valves different from each other.

  According to the in-cylinder injection spark ignition internal combustion engine according to claim 5 of the present invention, in the in-cylinder injection spark ignition internal combustion engine according to claim 2, the first fuel injection valve is disposed substantially at the upper center of the cylinder. The spark plug is disposed in the vicinity of the exhaust valve side of the first fuel injection valve, the second fuel injection valve is disposed on the exhaust valve side around the upper part of the cylinder, and the second fuel injection valve enhances the tumble flow during homogeneous combustion. Therefore, fuel is injected toward the piston top surface along the exhaust valve side of the cylinder bore in the vicinity of the intake bottom dead center. Accordingly, the tumble flow is strengthened by the fuel injected near the intake bottom dead center by the second fuel injection valve, and the first fuel injection valve is injected so as to pass through or near the ignition gap of the spark plug. The fuel in the vicinity of the intake bottom dead center can be injected obliquely downward toward the exhaust valve side of the cylinder bore to strengthen the tumble flow, and is similar to the direct injection spark ignition internal combustion engine according to claim 2. An effect can be obtained.

  According to the cylinder injection type spark ignition internal combustion engine according to claim 6 of the present invention, in the cylinder injection type spark ignition internal combustion engine according to claim 1, the cylinder injection type spark ignition internal combustion engine is an intake two-valve type. In the homogeneous combustion, the fuel injected from the first fuel injection valve in the vicinity of the intake bottom dead center strengthens one tumble flow formed in the cylinder via the one intake valve, and from the second fuel injection valve. The fuel injected in the vicinity of the intake bottom dead center reinforces the other tumble flow formed in the cylinder via the other intake valve. As a result, the two tumble flows formed in the cylinder via each intake valve are each strengthened by the injected fuel, and even if the two tumble flows merge in the first half of the compression stroke, they are reliably maintained until the second half of the compression stroke. Good homogeneous combustion can be realized.

  FIG. 1 is a schematic longitudinal sectional view in the vicinity of an intake bottom dead center showing a first embodiment of a direct injection spark ignition internal combustion engine according to the present invention. In the figure, reference numeral 1 denotes a first fuel injection valve that is arranged at substantially the center of the cylinder upper part and directly injects fuel into the cylinder, and 2 is arranged on the intake valve side around the cylinder upper part and into the cylinder. Reference numeral 3 denotes a second fuel injection valve for directly injecting fuel, and reference numeral 3 denotes an ignition plug disposed in the vicinity of the exhaust valve side of the first fuel injection valve 1. Reference numeral 4 denotes a piston. Although not shown, a pair of intake valves are arranged on the right side of the upper part of the cylinder, and a pair of exhaust valves are arranged on the left side of the upper part of the cylinder.

This in-cylinder injection spark ignition internal combustion engine forms a homogeneous air-fuel mixture that is leaner than the stoichiometric air-fuel ratio in a cylinder and performs homogeneous combustion in which this air-fuel mixture is ignited and burned by an ignition plug 3. The lean air-fuel ratio of this homogeneous combustion is set so that the amount of NO _x produced is relatively small (for example, 20). For example, when the engine speed is high and the load is high, homogeneous combustion at the stoichiometric air-fuel ratio or rich air-fuel ratio may be performed. Further, when the NO _X storing catalyst apparatus for storing the NO _X when the air-fuel ratio of the exhaust gas in the engine exhaust system is lean is located, to release the occluded NO _X from the NO _X storing catalyst apparatus reducing and purifying When performing, homogeneous combustion is performed with the combustion air-fuel ratio set to the set rich air-fuel ratio. In particular, in homogeneous combustion at a lean air-fuel ratio, a desired engine output cannot be obtained unless the combustion speed is increased by causing turbulence in the cylinder at the ignition timing. As a result, in the intake stroke, the tumble flow T (the piston top surface of the piston top surface) descends along the exhaust valve side of the cylinder bore and rises along the intake valve side by the intake air supplied to the cylinder in the intake stroke and turns vertically in the cylinder. The cylinder bore may rise in the cylinder without being along the intake valve side of the cylinder bore), and the tumble flow T is maintained until the ignition timing at the end of the compression stroke. It is preferable to cause disturbance in

  However, the tumble flow generally formed in the cylinder is not so strong unless the cylinder head is thickened and the shape of the intake port is devised, or the intake flow control valve is provided in the intake port. Due to the damping, it disappears easily by the second half of the compression stroke, and turbulence cannot exist in the cylinder due to the tumble flow at the ignition timing. Thereby, in the present embodiment, the tumble flow T formed in the cylinder in the intake stroke is directed toward the exhaust valve side of the cylinder bore by the first fuel injection valve 1 in the vicinity of the intake bottom dead center, preferably at the end of the intake stroke. In addition, the fuel F1 injected obliquely downward is strengthened by using the penetrating force, and is injected toward the exhaust valve side upper part of the cylinder bore by the second fuel injection valve 2 in the vicinity of the intake bottom dead center, preferably at the end of the intake stroke. The fuel F2 is pierced using the penetration force.

  When the tumble flow T is strengthened by a single injected fuel, the penetration force of the injected fuel cannot be increased so much in order to prevent the injected fuel from penetrating the tumble flow T and colliding with the cylinder bore or the piston top surface. However, as in the present embodiment, the required fuel amount determined according to the engine operating state is divided into two parts by the first fuel injection valve 1 and the second fuel injection valve 2, so that each injection is performed. Since the amount of fuel is reduced, even if the penetration force of the injected fuel is increased, it is difficult to penetrate the tumble flow T and collide with the cylinder bore or the piston top surface. Thereby, the penetration force of the injected fuels F1 and F2 can be increased, for example, so that the tip of the fuel after 1 ms from the start of injection reaches 60 mm or more, and the tumble flow T can be surely increased, and the tumble flow is compressed. It can be maintained until the second half, and the turbulence can exist in the cylinder at the ignition timing at the end of the compression stroke.

  In the present embodiment, the first fuel injection valve 1 and the second fuel injection valve 2 have, for example, a linear slit-shaped injection hole and inject fuel into a substantially thin fan shape or a circular arc. A fuel having a slit-like injection hole and having a relatively thin cross-sectional arc shape is injected (preferably, the upper side or the exhaust valve side is preferably projected as a convex), and the injected fuels F1 and F2 in the width direction are injected. The center plane is made to substantially coincide with a vertical plane passing through the cylinder center axis parallel to the tumble flow T. This vertical plane is a cross section of FIG. Of course, the fuel injection valve 1 may have a circular injection hole and inject fuel in a columnar or conical shape. Further, a plurality of circular injection holes are arranged in a linear or arc shape, and fuel is injected into a substantially fan shape having a relatively thin thickness as a whole, or a fuel having a relatively thin sectional arc shape as a whole. May be injected.

  In the present embodiment, the fuel is injected into the cylinder in the vicinity of the intake bottom dead center with the two fuel injection valves to strengthen the tumble flow T. Of course, the vicinity of the intake bottom dead center with the three or more fuel injection valves. In this case, fuel may be injected into the cylinder to strengthen the tumble flow T. The first fuel injection valve 1 and the second fuel injection valve 2 can be arbitrarily arranged as long as the tumble flow T can be strengthened by the injected fuel.

  In the present embodiment, the first fuel injection valve 1 is disposed substantially at the center of the cylinder upper portion, and the fuel injected from the first fuel injection valve 1 is an exhaust valve of the first fuel injection valve 1 as shown in FIG. The spark plug 3 is arranged so as to pass through an ignition gap of the spark plug 3 disposed in the vicinity of the side (the spark plug 3 is protruded greatly into the cylinder if necessary). Thus, if the fuel injected from the first fuel injection valve 1 passes through the ignition gap of the spark plug 3 or in the vicinity of the ignition gap, the first fuel injection valve 1 performs fuel injection in the second half of the compression stroke. As a result, the injected fuel is easily vaporized by friction with the intake air in the high-pressure cylinder to form a lump of combustible mixture in a part of the cylinder, and the ignition plug 3 is ignited in this combustible mixture. A gap can be positioned.

  Thus, according to the present embodiment, stratified combustion in which the combustible mixture is ignited and combusted by the spark plug 3 at the ignition timing at the end of the compression stroke can be performed. Stratified combustion cannot produce high engine power, but can reduce fuel consumption compared to homogeneous combustion. Thus, it is preferable to perform stratified combustion when the engine is under a low load.

  By the way, when fuel injection is simultaneously performed by the first fuel injection valve 1 and the second fuel injection valve 2 in the vicinity of the intake bottom dead center, the two injected fuels F1 and F2 merge as shown by arrows in FIG. The combined fuel F is deflected from the two injection directions and moves in the same direction due to the difference in the injection directions of the two injected fuels F1 and F2, and finally moves in the cylinder along the exhaust valve side of the cylinder bore. It will move downward and strengthen the tumble flow. As the fuel F moves, the surrounding air is also moved by friction, and in the vicinity of the upper part of the cylinder bore on the exhaust valve side, the air vortex swirling in the vertical direction is deflected by the collision with the cylinder bore in this way. S is formed.

  Since the swirl direction of the air vortex S thus formed is opposite to the tumble flow T, the air vortex S may collide with the tumble flow T and weaken the tumble flow T in the compression stroke. In this way, if the tumble flow T strengthened by the injected fuel is weakened by the collision with the air vortex S, the tumble flow T cannot be continued until the latter half of the compression stroke to cause turbulence in the cylinder at the ignition timing. Accordingly, in the present embodiment, the fuel injection timings of the first fuel injection valve 1 and the second fuel injection valve 2 in the vicinity of the intake bottom dead center are made different from each other so as not to coincide with each other. And the injected fuel F2 of the second fuel injection valve 2 are prevented from joining and moving. For example, the fuel injection of the first fuel injection valve 1 is started after the fuel injection of the second fuel injection valve 2 is completed. In this case, it is preferable that the fuel injection end timing of the first fuel injection valve 1 be the intake bottom dead center. Of course, the fuel injection end timing of the first fuel injection valve 1 may be set immediately before or immediately after the intake bottom dead center. Further, the fuel injection of the second fuel injection valve 2 may be started after the fuel injection of the first fuel injection valve 1 is completed. The point may be just before or just after the intake bottom dead center.

  FIG. 3 is a schematic longitudinal sectional view in the vicinity of the intake bottom dead center showing a second embodiment of the direct injection spark ignition internal combustion engine according to the present invention. Only differences from the first embodiment will be described below. In the present embodiment, the second fuel injection valve 2 ′ is disposed on the exhaust valve side around the cylinder upper portion, and injects fuel F2 ′ toward the piston top surface along the exhaust valve side of the cylinder bore in the vicinity of the intake bottom dead center. It is supposed to be. Since the fuel F2 ′ injected from the second fuel injection valve 2 ′ is pressed by the tumble flow T toward the exhaust valve side of the cylinder bore, the fuel F2 ′ is not parallel to the cylinder bore so as to suppress adhesion to the cylinder bore. As shown in FIG. 2, it is preferable that the liquid is injected slightly inward.

  Even with such a configuration, the fuel F1 injected near the intake bottom dead center from the first fuel injection valve 1 and the fuel F2 'injected near the intake bottom dead center from the second fuel injection valve 2 ′ can be tumbled well. The flow T can be strengthened. In the first embodiment, since the second fuel injection valve 2 injects the fuel F2 toward the exhaust valve side upper part of the cylinder bore, the injected fuel F2 adheres to the cylinder bore and dilutes the engine oil. However, in the present embodiment, the second fuel injection valve 2 ′ injects the fuel F2 ′ toward the piston top surface, so that the injected fuel F2 ′ does not adhere to the cylinder bore.

  FIG. 4 is a bottom view of a cylinder head in the vicinity of an intake bottom dead center showing a third embodiment of a cylinder injection type spark ignition internal combustion engine according to the present invention. In FIG. 4, a pair of intake valves 51 and 52 on the upper right side of the cylinder and a pair of exhaust valves 61 and 62 on the left side of the upper part of the cylinder are shown. In the present embodiment, the first fuel injection valve 1 ″ is disposed between one adjacent intake valve 51 and one exhaust valve 61 at the upper part of the cylinder, and the second fuel injection valve 2 ″ is provided at the upper part of the cylinder. It is arranged between the other intake valve 52 and the other exhaust valve 62 adjacent to each other. The spark plug 3 ″ is disposed between the pair of exhaust valves 61 and 62.

  In the case of the two-intake type, in the intake stroke, the intake air supplied from the intake valves 51 and 52 to the cylinders initially forms a tumble flow in the cylinder independently, and these two tumble flows Will merge into one tumble flow by the first half of the compression stroke. However, there are cases where the two tumble flows are not sufficiently merged in the vicinity of the intake bottom dead center, and at this time, a vertical plane passing through the middle of the two exhaust valves 61 and 62 and the middle of the two intake valves 51 and 52 ( The vicinity of the cross section in FIGS. 1 and 3 is a space between two tumble flows, and the fuel passing through the vicinity of the vertical plane cannot strengthen any tumble flow.

  In the first and second embodiments described above, the fuel injected from the first fuel injection valve and the second fuel injection valve is spread in the width direction, respectively, and even when the two tumble flows are not merged. The two tumble streams can be strengthened at the same time. However, a part of each injected fuel passes through the vicinity of the above-described vertical plane and is not used to enhance the tumble flow.

  On the other hand, in the present embodiment, the fuel F1 ″ injected obliquely downward from the first fuel injection valve 1 ″ toward the exhaust valve side of the cylinder bore in the vicinity of the intake bottom dead center is one intake valve 51. The fuel F2 "injected into the cylinder bore from the second fuel injection valve 2" toward the exhaust valve side of the cylinder bore is intensified by the other intake valve 52. The other tumble flow formed in the cylinder is strengthened via the, and almost all of the injected fuel is used to strengthen one of the tumble flows. As a result, the two tumble flows are strengthened well and merged in the first half of the compression stroke and reliably maintained until the latter half of the compression stroke, and the turbulence can be reliably present in the cylinder at the ignition timing.

  In the present embodiment, the first fuel injection valve 1 "and the second fuel injection valve 2" inject fuel in a substantially fan shape having a relatively small thickness, as shown in FIG. In this way, if the injected fuel spreads in the width direction, the two injected fuels injected obliquely downward are both the ignition gaps of the spark plug 3 ″ disposed between the two exhaust valves 61 and 62. If the fuel is injected in the latter half of the compression stroke by one or both of the first fuel injection valve 1 "and the second fuel injection valve 2", the above-mentioned may be allowed. Similarly, stratified combustion can also be realized. Also in this embodiment, the shape of the injected fuel of the first fuel injection valve 1 "and the second fuel injection valve 2" can be selected in the same manner as in the first embodiment. is there.

  Further, since the stratified combustion can be realized also by the compression stroke fuel injection of only one of the first fuel injection valve 1 ″ and the second fuel injection valve 2 ″, the shape of the fuel injected from the other fuel injection valve is The spread angle of the direction may be reduced so that it does not pass near the ignition gap of the spark plug 3 ″. Thereby, the vicinity of the intake bottom dead center by the first fuel injection valve 1 ″ and the second fuel injection valve 2 ″. In this fuel injection, the two injected fuels F1 "and F2" are prevented from colliding with each other, and the penetration force of each of the two injected fuels F1 "and F2" is effectively used to strengthen the corresponding tumble flow. be able to.

1 is a schematic longitudinal sectional view in the vicinity of an intake bottom dead center showing a first embodiment of a direct injection spark ignition internal combustion engine according to the present invention. FIG. 2 is a diagram for explaining a case where the injected fuel of the first fuel injection valve and the injected fuel of the second fuel injection valve merge in the in-cylinder injection spark ignition internal combustion engine of FIG. 1. FIG. 6 is a schematic longitudinal sectional view in the vicinity of an intake bottom dead center showing a second embodiment of a direct injection spark ignition internal combustion engine according to the present invention. FIG. 6 is a bottom view of a cylinder head in the vicinity of an intake bottom dead center showing a third embodiment of a direct injection spark ignition internal combustion engine according to the present invention.

Explanation of symbols

1, 1 ″ first fuel injection valve 2, 2 ′, 2 ″ second fuel injection valve 3, 3 ″ spark plug T tumble flow F1, F2, F2 ′, F1 ″, F2 ″ injection fuel

Claims (6)

  At least two first fuel injection valves and second fuel injection valves that inject fuel directly into the cylinder, and in homogeneous combustion, descend along the exhaust valve side of the cylinder bore and turn vertically in the cylinder An in-cylinder injection spark ignition internal combustion engine characterized in that the tumble flow is strengthened by the fuel injected in the vicinity of the intake bottom dead center by the at least two first fuel injection valves and the second fuel injection valve.   The fuel injected by the first fuel injection valve passes through the ignition gap of the spark plug or in the vicinity of the ignition gap, and injects fuel by the first fuel injection valve in the latter half of the compression stroke, thereby 2. The direct injection spark ignition internal combustion engine according to claim 1, wherein stratified combustion is performed by positioning an ignition gap of the spark plug in a combustible mixture formed in a part of the spark plug.   The first fuel injection valve is disposed substantially in the center of the cylinder upper portion, the spark plug is disposed in the vicinity of the exhaust valve side of the first fuel injection valve, and the second fuel injection valve is disposed on the intake valve side around the cylinder upper portion. 3. In homogeneous combustion, the second fuel injection valve injects fuel toward the exhaust valve side upper part of the cylinder bore in the vicinity of the intake bottom dead center in order to strengthen the tumble flow. The in-cylinder injection spark ignition internal combustion engine described.   4. The direct injection spark ignition internal combustion engine according to claim 3, wherein the fuel injection timings of the first fuel injection valve and the second fuel injection valve in the vicinity of the intake bottom dead center are made different from each other during homogeneous combustion. .   The first fuel injection valve is disposed substantially at the center of the cylinder upper portion, the spark plug is disposed in the vicinity of the exhaust valve side of the first fuel injection valve, and the second fuel injection valve is disposed on the exhaust valve side around the cylinder upper portion. In the homogeneous combustion, the second fuel injection valve injects fuel toward the piston top surface along the exhaust valve side of the cylinder bore in the vicinity of the intake bottom dead center in order to strengthen the tumble flow. The in-cylinder injection spark ignition internal combustion engine according to claim 2.   The in-cylinder injection spark-ignition internal combustion engine is an intake two-valve type, and during homogeneous combustion, fuel injected near the intake bottom dead center by the first fuel injection valve is formed in the cylinder through one intake valve. One of the tumble flows is strengthened, and the fuel injected near the intake bottom dead center by the second fuel injection valve strengthens the other tumble flow formed in the cylinder via the other intake valve. The in-cylinder injection spark ignition internal combustion engine according to claim 1.

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