JP2003003854A - In-cylinder direct injection spark ignition internal combustion engine and method for forming air-fuel mixture in in-cylinder direct injection spark ignition internal combustion engine - Google Patents

Abstract

(57) [Problem] To provide a direct injection spark ignition internal combustion engine with high output and high efficiency and a method of forming the mixture by satisfying both stratified mixture formation and homogeneous mixture formation. SOLUTION: A direct injection spark ignition internal combustion engine 10A has a guide plate 3 as a tumble flow control means in an intake port 22.
The guide plate 34 is configured to be able to control (change) the state of separation of the airflow from the wall surface in the throat lower part 32 by moving the guide plate 34 into and out of the intake port 2. When the separation state of the airflow from the wall surface in the lower part of the throat 32 is changed by the operation of the guide plate 34, the bias of the intake airflow is changed, so that the generation state (strength) of the gas tumble flow in the combustion chamber 16 can be controlled. As a result, the formation of a stratified mixture (partial load state) and the formation of a homogeneous mixture (high load state) can both be satisfied to achieve high output and high efficiency.

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 spark ignition internal combustion engine in which fuel is directly injected into a cylinder to form an air-fuel mixture, and the air-fuel mixture is ignited and burned by an ignition plug, and the in-cylinder direct injection. The present invention relates to a method for forming an air-fuel mixture in a spark ignition internal combustion engine.

[0002]

2. Description of the Related Art There is known an in-cylinder direct injection spark ignition internal combustion engine (so-called direct injection gasoline engine) which directly injects fuel into a combustion chamber (cylinder) and ignites and burns by spark ignition.

In an existing in-cylinder direct injection spark ignition internal combustion engine of this type, when a rich air-fuel mixture is formed in the vicinity of a spark plug and a lean air-fuel mixture is formed around it, the average air-fuel ratio of the whole is considerably low. However, there is one configured to perform so-called stratified combustion for the purpose of enabling ignition and improving fuel consumption in a low load range (partial load). Moreover, it is generally based on the concept of utilizing the wall shape of the combustion chamber for stratified combustion, that is, for forming the stratified mixture. In other words, by injecting fuel spray toward the cavity provided on the top surface of the piston and devising the shape of the cavity wall, the direction of spray movement can be changed and fuel can be retained in the cavity to form a stratified mixture. It is a structure to be formed.

However, in the conventional internal combustion engine based on the concept of utilizing the wall shape of the combustion chamber to form such a stratified mixture, the influence of the shape of the combustion chamber on the formation of the mixture and thus the engine performance is large. , It was not easy to optimize its shape. Further, in the piston cavity having a complicated shape, the heat loss increases as the surface area of the combustion chamber increases, and the heat efficiency deteriorates.

Therefore, the development of a combustion system such as a so-called "air guide" or "spray guide" which does not utilize the cavity wall as described above (which is not a factor) in the formation of the stratified mixture is under way. Among them, the one based on the concept of "air guide" uses the air flow to guide the air-fuel mixture to the ignition position. In this case, a strong in-cylinder flow (gas tumble flow in the cylinder) is required to form a stratified mixture in the low load region (partial load), while on the other hand, a uniform mixture is formed at high load. It is considered that a very strong in-cylinder flow is not preferable because the spray may be washed away and the air-fuel mixture may be unevenly distributed and the cooling loss may be increased. Therefore, in the one based on the concept of using the airflow to form the air-fuel mixture, a variable mechanism that can change the flow of intake air between partial load (low load range) and high load is required. For this reason, conventionally, a partition wall that divides the intake port into two parts (which divides the air flow into upper and lower parts) is provided in the intake port. A flow rate adjusting valve for adjusting the flow rate is provided. The normal tumble flow is strengthened by closing the flow rate adjusting valve, while the normal tumble flow is weakened by opening the flow rate adjusting valve.

However, in the conventional structure as described above, since the partition wall for dividing the air flow into two is provided in the intake port, the flow path resistance is inevitably large, and the intake air amount when fully opened. Since it is limited, there is a drawback that high output cannot be expected.

[0007]

SUMMARY OF THE INVENTION In consideration of the above facts, the present invention considers the above facts and forms a stratified mixture for stratified combustion at low load, which is a contradictory requirement, and a homogeneous mixture for homogeneous combustion at high load. Satisfying both the mixture formation and
It is an object of the present invention to provide a direct injection spark ignition internal combustion engine with high output and high efficiency that is excellent in performance during both combustions, and a mixture forming method in the direct injection spark ignition internal combustion engine.

[0008]

An in-cylinder direct injection spark ignition internal combustion engine of the invention according to claim 1 sucks air from an intake pipe,
Direct in-cylinder eruption in which fuel is directly injected into the cylinder by an injection valve installed at a position distant from the center of the cylinder to form an air-fuel mixture, and the air-fuel mixture is ignited and burned by an ignition plug installed substantially in the center of the cylinder. In the flower ignition internal combustion engine, a tumble flow control means is provided that can change the generation state of the gas tumble flow in the cylinder by controlling the separation state from the wall surface of the air flow in the lower portion of the intake port throat of the intake pipe, It is characterized by that.

In the in-cylinder direct injection spark ignition internal combustion engine according to the first aspect, the separation state from the wall surface of the air flow in the lower portion of the intake port throat is controlled (changed) by the operation of the tumble flow control means. As a result, the generation state of the gas tumble flow in the cylinder is changed. That is, when the air flow in the lower part of the intake port throw is largely separated by the tumble flow control means, the air flow in the intake port is lopsided and the effective flow passage area is reduced, so that the gas tumble flow in the cylinder is generated. Can be strengthened. On the other hand, if the separation of the airflow in the lower part of the intake port throw is suppressed by the tumble flow control means, the airflow in the intake port does not become uneven, and the generation of the gas tumble flow in the cylinder is weakened. Moreover, when the separation of the airflow is suppressed in this way, the flow path resistance does not increase.

In such an in-cylinder direct injection spark ignition internal combustion engine, the air flow plays a large role in forming the air-fuel mixture. Further, in the low load region (during partial load), it is necessary to stratify the air-fuel mixture around the spark plug, while at the time of high load, it is necessary to form a homogeneous air-fuel mixture.

In this respect, in the in-cylinder direct injection spark ignition internal combustion engine according to the first aspect, the generation state of the gas tumble flow in the cylinder is changed by the operation of the tumble flow control means.
It is possible to satisfy the conflicting air-fuel mixture formation requirements without impairing the fully open intake amount. That is, when forming the stratified mixture for stratified combustion (partial load), the mixture can be carried to the ignition plug position by strengthening the generation state of the gas tumble flow in the cylinder. On the other hand, when a homogeneous mixture is formed for homogeneous combustion (at high load), the amount of intake air is secured, the generation state of gas tumble flow in the cylinder is weakened, and spray is swept away and unevenly distributed in the combustion chamber. Can be prevented. Further, excessive cooling loss can be suppressed, resulting in high output and high efficiency.

As described above, in the direct injection spark ignition internal combustion engine according to the first aspect of the present invention, formation of a stratified mixture for stratified combustion at low load and homogeneous combustion at high load, which are mutually contradictory requirements. The formation of a homogeneous mixture for the above conditions can both be satisfied, and high output and high efficiency with excellent performance during both combustions can be achieved.

The cylinder direct injection spark ignition internal combustion engine of the invention according to claim 2 is the cylinder direct injection spark ignition internal combustion engine according to claim 1, wherein the tumble flow control means is an upstream end of the intake port throat. A portion is rotatably supported by the intake port throat wall, and is a guide plate for advancing and retracting into the intake port by rotating around the supporting position to control the separation state of the airflow from the wall surface. It is characterized by that.

In the in-cylinder direct injection spark ignition internal combustion engine according to the second aspect, the guide plate provided on the intake port throat rotates around the support position and moves back and forth into the intake port, so that the wall surface of the air flow is removed. The peeling state is controlled (changed). That is, since the deviation of the intake airflow is changed by changing the amount of advance / retreat of the guide plate into / from the intake port, it is possible to control the generation state (strength) of the gas tumble flow in the cylinder.

A cylinder direct injection spark ignition internal combustion engine according to a third aspect of the present invention is the cylinder direct injection spark ignition internal combustion engine according to the first aspect, wherein the tumble flow control means is provided on the intake port throat wall. The protrusion is a protrusion that controls the separation state of the airflow from the wall surface by projecting and retracting into the intake port.

In the in-cylinder direct injection spark ignition internal combustion engine according to the third aspect of the present invention, the state of separation of the air flow from the wall surface is controlled by the protrusion provided on the intake port throat wall protruding and retracting into the intake port ( Be changed. That is, since the deviation of the intake airflow is changed by changing the amount of protrusion of the protrusion into the intake port, the generation state (strength) of the gas tumble flow in the cylinder can be controlled.

The cylinder direct injection spark ignition internal combustion engine of the invention according to claim 4 is the cylinder direct injection spark ignition internal combustion engine according to claim 1, wherein the tumble flow control means communicates with a lower portion of the intake port throat. A sub-intake passage that is provided in the intake port and is capable of blowing air into the intake port; and a regulating valve that is provided in the sub-intake passage to adjust the blowing amount of the air.
It is characterized by having.

In the cylinder direct injection spark ignition internal combustion engine according to the fourth aspect, the amount of air blown out into the intake port is adjusted by the adjusting valve provided in the auxiliary intake passage, so that the air flow from the wall surface of the air flow is adjusted. The peeling state is controlled (changed). That is,
When the adjustment valve is closed to eliminate the air blow (inflow) from the auxiliary intake flow path into the intake port, the air flow separates at the lower part of the intake port throat, and the gas tumble flow generation state (strength ) Can be strengthened. on the other hand,
When the adjustment valve is opened and air is blown out (inflow) from the auxiliary intake flow path into the intake port, energy is supplied to the boundary layer of the air flow at the lower part of the intake port throat, and air flow separation is suppressed. As a result, the flow adheres to the wall surface, and the generation state (strength) of the gas tumble flow in the cylinder can be weakened.

As described above, since the separated state of the intake airflow is changed by opening / closing the adjusting valve, the generation state (strength) of the gas tumble flow in the cylinder can be controlled.

An in-cylinder direct injection spark ignition internal combustion engine according to a fifth aspect of the present invention is the in-cylinder direct injection spark ignition internal combustion engine according to any one of the first to fourth aspects, wherein the tumble flow control means is provided. The separation point of the air flow in the lower portion of the intake port throat is characterized in that when the diameter of the intake valve is D, the distance is within 2D upstream from the combustion chamber inlet of the intake port.

In the direct injection spark ignition internal combustion engine according to the fifth aspect, when the separation point of the air flow in the lower part of the intake port throat generated by the tumble flow control means is the intake port combustion when the diameter of the intake valve is D. Since the distance from the chamber inlet to the upstream side is within 2D, the separated flow does not redeposit in the intake port, and the intake air flow is biased smoothly to generate the gas tumble flow in the cylinder. Can be suitably changed.

According to a sixth aspect of the present invention, there is provided a method for forming an air-fuel mixture in a direct injection spark ignition internal combustion engine, comprising the steps of: forming an air-fuel mixture in a direct injection spark ignition internal combustion engine according to any one of the first to fifth aspects. A forming method, in the partial load state,
By strengthening the gas tumble flow in the cylinder, a stratified air-fuel mixture is formed around the spark plug, and under high load conditions, the gas tumble flow in the cylinder is weakened to form a homogeneous air-fuel mixture in the combustion chamber. The feature is that

According to the sixth aspect of the method for forming the air-fuel mixture in the direct injection spark ignition internal combustion engine, the fuel is directly injected into the cylinder by the injection valve installed at a position distant from the center of the cylinder. During partial load, the flow is separated at the lower part of the intake port throat to strengthen the gas tumble flow in the cylinder, so that the air-fuel mixture is carried to the spark plug position, so that a stratified air-fuel mixture is formed around the spark plug and stable. Combustion can be secured. On the other hand, when the load is high, the flow adheres to the wall surface at the lower part of the intake port throat to secure the amount of intake air, weaken the gas tumble flow in the cylinder, and prevent the spray from being swept by the air flow and unevenly distributed. A homogeneous mixture can be formed. Further, since excessive cooling loss can be suppressed, it is possible to provide an internal combustion engine with high output and high efficiency.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a basic structure of a main part of a direct injection spark ignition internal combustion engine 10 according to an embodiment of the present invention.

In this direct injection spark ignition internal combustion engine 10,
A combustion chamber 16 is formed by the cylinder block 12 and the cylinder head 14, and a piston 18 is housed in the combustion chamber 16. This piston 18
Is connected to the crankshaft via a connecting rod (not shown). Further, the cylinder head 14 is provided with a fuel injection valve 20. This fuel injection valve 20
The spray is arranged at a position away from the center of the cylinder block 12 (combustion chamber 16), and a spray having a spray length shorter than that of the single hole nozzle can be directly injected into the combustion chamber 16.

The combustion chamber 16 has a cylinder head 14
The intake port 22 and the exhaust port 24 formed in the above are communicated with each other. The intake port 22 is provided with an intake valve 26, and the exhaust port 24 is provided with an exhaust valve 28. Further, a spark plug 30 is attached to a central portion of the cylinder head 14 (between the intake port 22 and the exhaust port 24).

In the in-cylinder direct injection spark ignition internal combustion engine 10 having the above basic structure, the intake port 22 is provided during the intake stroke.
In the cylinder (combustion chamber 16
The inside is provided with a tumble flow control means capable of changing the generation state of the gas tumble flow. That is, FIG. 2 (A)
As shown in FIG. 3, when the airflow is separated from the wall surface in the throat lower portion 32, the intake flow at the valve opening of the intake port 22 is biased toward the exhaust valve 28 side, and the effective flow passage area of the intake port 22 decreases. Since the flow velocity increases, a strong positive gas tumble flow can be generated in the cylinder (in the combustion chamber 16). On the other hand, as shown in FIG. 2B, when the separation of the intake airflow in the throat lower part 32 of the intake port 22 is suppressed and the flow adheres to the wall surface, the airflow in the intake port 22 does not become uneven, and the intake port 2
Since the airflow flows into the combustion chamber 16 from the entire circumference of the second valve opening, the generation of the gas tumble flow in the cylinder (inside the combustion chamber 16) is weakened.

The structure and operation of the tumble flow control means for controlling the separated state of the air flow in the throat lower part 32 of the intake port 22 will be described below. (First embodiment) As shown in FIGS. 3 (A) and 3 (B),
In-cylinder direct injection spark ignition internal combustion engine 10A in the first embodiment
Is provided with a guide plate 34 as a tumble flow control means. As shown in FIG. 4, the guide plate 34 has its upstream end portion in the intake port 22 rotatably supported by the wall of the throat lower portion 32 of the intake port 22 about the support shaft 36. It is configured so that it can be moved into and out of the intake port 22 by rotating to. In this case, the original (original) shape of the intake port 22 is set to a shape that does not cause air flow separation in the lower throat 32. By advancing and retracting the guide plate 34 into and out of the intake port 22, it is possible to control the separation state of the air flow in the lower throat 32 from the wall surface.

As shown in FIG. 4, the intake port 22
When there are a plurality of guide plates 34, each guide plate 34 is supported by the same (common) support shaft 36.

Further, the width dimension of the guide plate 34 is set to about "1/4 to 1/2" of the circumferential length of the intake port 22. Further, the separation point of the air flow in the throat lower part 32 of the intake port 22 caused by the guide plate 34 is 2D upstream from the inlet of the combustion chamber 16 of the intake port 22 when the diameter of the intake valve 26 is D.
It is set within the distance.

In the in-cylinder direct injection spark ignition internal combustion engine 10A provided with the guide plate 34 having the above-mentioned structure, the operation of the guide plate 34 controls (changes) the state of separation of the air flow in the throat lower part 32 of the intake port 22 from the wall surface. To be done. As a result, the generation state of the gas tumble flow in the combustion chamber 16 is changed. That is, as shown in FIG.
Guide plate 34 by pulling out air into the intake port 22.
If the airflow in the throat lower portion 32 of the intake port 22 is largely separated at the tip, the airflow in the intake port 22 will be lopsided and the effective flow passage area will be reduced.
The generation of gas tumble flow in the combustion chamber 16 is enhanced. On the other hand, as shown in FIG. 3 (B), when the guide plate 34 is drawn into the wall of the intake port 22 to suppress the separation of the air flow in the lower portion throat 32 of the intake port 22, the air flow in the intake port 22 does not become uneven. The generation of the gas tumble flow in the combustion chamber 16 is weakened. Moreover, when the separation of the airflow is suppressed in this way, the flow path resistance in the intake port 22 does not increase.

In this way, the intake port 2 of the guide plate 34
Since the deviation of the intake airflow is changed by changing the advancing / retreating amount to the inside of 2, the generation state (strength) of the gas tumble flow in the combustion chamber 16 can be controlled.

In such an in-cylinder direct injection spark ignition internal combustion engine 10A, the air flow plays a large role in forming the air-fuel mixture. In the low load region (partial load), it is necessary to stratify the air-fuel mixture around the spark plug 30, while
At high load, it is necessary to form a homogeneous air-fuel mixture in the combustion chamber 16.

In this respect, in the in-cylinder direct injection spark ignition internal combustion engine 10A having the above structure, the combustion chamber 1 is operated by the operation of the guide plate 34.
By changing the generation state of the gas tumble flow in 6, the contradictory air-fuel mixture formation requirements can be satisfied without impairing the fully open intake amount. That is, when the stratified mixture is formed for the stratified combustion (partial load state), the combustion chamber 16
By strengthening the generation state of the gas tumble flow in the
The mixture can be carried to the spark plug 30 position. On the other hand, when forming a homogeneous air-fuel mixture for a homogeneous combustion (high load state), the amount of intake air is secured and the generation state of the gas tumble flow in the combustion chamber 16 is weakened so that the spray is swept away and the combustion chamber is pushed. Uneven distribution within 16 can be prevented. Also,
Excessive cooling loss can be suppressed, resulting in high output and high efficiency.

Thus, the direct injection spark ignition internal combustion engine 1
At 0 A, the performance of both combustions is satisfied by satisfying both the formation of a stratified mixture for stratified combustion at low load and the formation of a homogeneous mixture for homogeneous combustion at high load, which are mutually contradictory requirements. It can have excellent high output and high efficiency. (Second Embodiment) As shown in FIGS. 5 (A) and 5 (B),
In-cylinder direct injection spark ignition internal combustion engine 10B in the second embodiment
Includes a vortex generator (projection) 38 as a tumble flow control means. In this in-cylinder direct injection spark ignition internal combustion engine 10B, the original (original) intake port 22 is set to a shape that causes airflow separation in the throat lower portion 32. A plurality of vortex generators 38 are arranged in the lower portion of the throat 32 of the intake port 22 from upstream of the separation point of the airflow to near the separation point, and are configured to project and retract inside the intake port 22. Also in this case, when the diameter of the intake valve 26 is D, the separation point of the airflow in the throat lower portion 32 of the intake port 22 becomes
The distance is set within 2D upstream from the inlet of the second combustion chamber.

By making the vortex generator 38 project into and retract from the intake port 22, it is possible to control the state of separation of the air flow at the lower portion of the throat 32 from the wall surface.

The vortex generator 38 having the above structure
In a direct injection spark ignition internal combustion engine 10B equipped with
As shown in (A), by pulling the vortex generator 38 into the wall of the intake port 22, separation of the air flow occurs at the lower portion of the throat 32, and the generation of the gas tumble flow in the combustion chamber 16 is strengthened. On the other hand, as shown in FIG.
When the vortex generator 38 is drawn out into the intake port 22, energy can be supplied to the wall boundary layer by generation of vortices, so that separation of the air flow is suppressed and the combustion chamber 16
The generation of the gas tumble flow inside is weakened.

In this way, the vortex generator 3
By changing the amount of protrusion of 8 into the intake port 22,
Since the deviation of the intake airflow changes, the generation state (strength) of the gas tumble flow in the combustion chamber 16 can be controlled.

Therefore, in the in-cylinder direct injection spark ignition internal combustion engine 10B having the above configuration, the generation state of the gas tumble flow in the combustion chamber 16 is changed by the operation of the vortex generator 38, so that the full open intake amount is not impaired. It is possible to meet the requirement of forming a mixture. That is,
When forming the stratified mixture for the stratified combustion (partial load state), the mixture can be carried to the spark plug 30 position by strengthening the generation state of the gas tumble flow in the combustion chamber 16. On the other hand, when forming a homogeneous mixture for homogeneous combustion (high load state), while weakening the generation state of the gas tumble flow in the combustion chamber 16 while securing the intake air amount,
It is possible to prevent the spray from being washed away and unevenly distributed in the combustion chamber 16. Further, excessive cooling loss can be suppressed, resulting in high output and high efficiency.

As described above, the direct injection spark ignition internal combustion engine 1
In 0B, both of the performances of both combustions are satisfied by satisfying both the stratified mixture formation for the stratified combustion at low load and the homogeneous mixture formation for the homogeneous combustion at high load, which are mutually contradictory requirements. It can have excellent high output and high efficiency. (Third Embodiment) As shown in FIGS. 6 (A) and 6 (B),
In-cylinder direct injection spark ignition internal combustion engine 10C in the third embodiment
Is provided with an auxiliary intake flow passage 40 that constitutes a tumble flow control means. The auxiliary intake flow passage 40 is provided so as to communicate with the throat lower portion 32 of the intake port 22.
Air can be blown inside. Further, the auxiliary intake flow passage 40 is also provided with a regulating valve 42 which also constitutes a tumble flow control means. The adjusting valve 42 is capable of adjusting the amount of air blown from the auxiliary intake passage 40 into the intake port 22. In this case, the original (original) shape of the intake port 22 is set to a shape that causes airflow separation in the throat lower portion 32. Also in this case, the intake port 22
The separation point of the air flow in the throat lower part 32 of the intake valve 2
When the diameter of 6 is D, the distance is set within 2D from the combustion chamber inlet of the intake port 22 to the upstream side. Further, the auxiliary intake flow passage 40 is configured to communicate with the intake port 22 upstream of the airflow separation point in the lower throat 32.

By adjusting the amount of air blown from the auxiliary air intake passage 40 into the intake port 22, it is possible to control the state of separation of the air flow in the lower throat 32 from the wall surface.

The auxiliary intake flow passage 40 and the adjusting valve 42 having the above-mentioned configuration
In the in-cylinder direct injection spark ignition internal combustion engine 10C equipped with
As shown in (A), the adjusting valve 42 is closed to close the auxiliary intake passage 40.
When the blowout (inflow) of air from the intake port 22 into the intake port 22 is eliminated, the air flow is at the throat lower part 3 of the intake port 22.
The separation occurs at 2, and the generation state (strength) of the gas tumble flow in the combustion chamber 16 can be strengthened. On the other hand, FIG.
As shown in (B), the adjustment valve 42 is opened to open the auxiliary intake passage 40.
When there is a blowout (inflow) of air from the intake port 22 into the intake port 22, energy is supplied to the boundary layer of the airflow in the throat lower portion 32 of the intake port 22, and the separation of the airflow is suppressed and the flow is blocked by the wall surface. And the generation state (strength) of the gas tumble flow in the combustion chamber 16 can be weakened.

Thus, by opening and closing the adjusting valve 42,
Since the separated state of the intake airflow changes, the generation state (strength) of the gas tumble flow in the combustion chamber 16 can be controlled.

Therefore, in the in-cylinder direct injection spark ignition internal combustion engine 10C having the above structure, the generation state of the gas tumble flow in the combustion chamber 16 is changed by the operation of the adjusting valve 42.
It is possible to satisfy the conflicting air-fuel mixture formation requirements without impairing the fully open intake amount. That is, when forming a stratified mixture for stratified combustion (partial load state), the combustion chamber 1
By strengthening the generation state of the gas tumble flow in 6, the air-fuel mixture can be carried to the position of the spark plug 30.
On the other hand, when forming a homogeneous air-fuel mixture for a homogeneous combustion (high load state), the amount of intake air is secured and the generation state of the gas tumble flow in the combustion chamber 16 is weakened so that the spray is swept away and the combustion chamber is pushed. Uneven distribution within 16 can be prevented. Further, excessive cooling loss can be suppressed, resulting in high output and high efficiency.

Thus, the direct injection spark ignition internal combustion engine 1
At 0C, both the conditions of both combustions are satisfied by satisfying both the formation of a stratified mixture for low-load stratified combustion and the formation of a homogeneous mixture for high-load homogeneous combustion, which are mutually contradictory requirements. It can have excellent high output and high efficiency.

[0046]

As described above, in the cylinder direct injection spark ignition internal combustion engine and the method for forming the air-fuel mixture in the cylinder direct injection spark ignition internal combustion engine according to the present invention, the stratification at low load, which is a conflicting requirement. By satisfying both the formation of stratified mixture for combustion and the formation of homogeneous mixture for high-load combustion, it has the excellent effect of high output and high efficiency with excellent performance during both combustions. is doing.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a basic configuration of a main part of a direct injection spark ignition internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a state of an intake air flow in an intake port of a direct injection spark ignition internal combustion engine according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing a configuration of a main part of an in-cylinder direct injection spark ignition internal combustion engine and a state of an intake air flow according to a first example of an embodiment of the present invention.

FIG. 4 is a schematic configuration diagram from a top view showing an arrangement state of guide plates of the in-cylinder direct injection spark ignition internal combustion engine shown in FIG.

FIG. 5 is a schematic cross-sectional view showing a configuration of a main part of an in-cylinder direct injection spark ignition internal combustion engine and a state of intake air flow according to a second example of the embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view showing a configuration of a main part of an in-cylinder direct injection spark ignition internal combustion engine and a state of intake air flow according to a third example of an embodiment of the present invention.

[Explanation of symbols]

10 in-cylinder direct injection spark ignition internal combustion engine 10A in-cylinder direct injection spark ignition internal combustion engine 10B in-cylinder direct injection spark ignition internal combustion engine 10C in-cylinder direct injection spark ignition internal combustion engine 16 combustion chamber 20 fuel injection valve 22 intake port 24 exhaust port 26 Intake valve 28 Exhaust valve 30 Spark plug 32 Lower throat 34 Guide plate (tumble flow control means) 38 Vortex generator (tumble flow control means) 40 Secondary intake flow path (tumble flow control means) 42 Regulator valve (tumble flow control means)

Claims (6)

[Claims] 1. A spark plug installed in substantially the center of the cylinder by inhaling air from an intake pipe and directly injecting fuel into the cylinder by an injection valve installed at a position distant from the center of the cylinder to form an air-fuel mixture. In a cylinder direct injection spark ignition internal combustion engine that ignites and burns the air-fuel mixture by means of a gas tumble flow in the cylinder by controlling the state of separation of the airflow from the wall surface of the intake pipe below the intake port throat. An in-cylinder direct injection spark ignition internal combustion engine, characterized in that tumble flow control means capable of changing the state is provided. 2. The tumble flow control means is configured such that an upstream end of the intake port throat is rotatably supported by the intake port throat wall, and the tumble flow control means rotates within the intake port by rotating around the support position. The in-cylinder direct injection spark ignition internal combustion engine according to claim 1, which is a guide plate that advances and retreats to control the state of separation of the airflow from the wall surface. 3. The tumble flow control means is provided on the intake port throat wall, and is a protrusion that controls the separation state of the airflow from the wall surface by protruding and retracting into the intake port. The in-cylinder direct injection spark ignition internal combustion engine according to claim 1. 4. The tumble flow control means is provided in communication with a lower portion of the intake port throat, and is provided in an auxiliary intake flow passage capable of blowing air into the intake port, and in the auxiliary intake flow passage, An in-cylinder direct injection spark ignition internal combustion engine according to claim 1, further comprising: a regulating valve that regulates the amount of air blown out. 5. The separation point of the air flow in the lower part of the intake port throat generated by the tumble flow control means is a distance within 2D upstream from the combustion chamber inlet of the intake port when the diameter of the intake valve is D. The in-cylinder direct injection spark ignition internal combustion engine according to any one of claims 1 to 4, characterized in that. 6. A method for forming an air-fuel mixture in a cylinder direct injection spark ignition internal combustion engine according to claim 1, wherein the gas tumble flow in the cylinder is set in a partial load state. A cylinder characterized by forming a stratified air-fuel mixture around the spark plug by strengthening it, and by weakening the gas tumble flow in the cylinder in a high load state, forming a homogeneous air-fuel mixture in the combustion chamber. Method for forming air-fuel mixture in internal combustion engine with direct injection spark ignition.