JP4732381B2 - Fuel injection apparatus and fuel injection method for internal combustion engine - Google Patents

Description

The present invention relates to a fuel injection device and a fuel injection method for an internal combustion engine. More specifically, the present invention relates to a fuel injection apparatus and a fuel injection method. The present invention relates to a technique for improving fuel vaporization performance.

Patent Document 1 discloses a swirl control device in which a part of a nozzle hole of a fuel injection valve is closed with a swirl control valve when the swirl control valve is closed.
According to the swirl control device, the injection direction can be changed by partially blocking the injection hole of the fuel injection valve with the swirl control valve, and the change in the injection direction is changed to a strong air flow by the swirl control valve. By adapting, the amount of fuel adhering to the intake port wall surface when the swirl control valve is closed can be reduced.
JP-A-9-088773

However, if a part of the injection hole of the fuel injection valve is blocked by a swirl control valve as in the prior art, it becomes difficult to inject the required amount of fuel, and the fuel injection amount becomes insufficient and the engine output May be reduced.
In addition, when the injection hole of the fuel injection valve is closed with the swirl control valve, if sufficient sealing performance cannot be secured, fuel leaks from the injection hole portion that should be closed, and this flows through the swirl control valve to the intake port. It adheres to the wall surface and flows into the cylinder in the liquid state from the intake port wall surface, which causes an increase in the amount of HC in the exhaust.

Furthermore, when the swirl control valve imparts a drift to the intake air and has two intake ports in one cylinder, the air flow in one intake port is strengthened and the air flow in the other intake port is relatively weakened. In general, swirl is generated in the combustion chamber.
However, since the penetration due to the spray pressure is strong, there is a difference in the strength of the air flow between the intake ports even if a means for actively changing the injection direction, such as closing part of the nozzle hole, is not executed. Even so, the fuel spray is not drawn into the strong air flow.

Therefore, there is no change in the amount of fuel injected into both intake ports, and in an intake port with a strong air flow, atomization and vaporization of fuel spray are sufficiently promoted, whereas an intake air with a weak air flow is used. In the port, since the ratio of the fuel to the air flow is large, there arises a problem that the fuel spray cannot be sufficiently atomized and vaporized.
The present invention has been made in view of the above problems. In an internal combustion engine that generates a vortex flow such as a swirl in a combustion chamber by causing a difference in strength of air flow between two intake ports, the required fuel amount is reduced. The purpose is to reliably reduce the amount of HC in the exhaust while injecting, and in particular to improve the vaporization performance by paying attention to the difference in atomization and vaporization performance due to the difference in air flow strength. To do.

Therefore, in the fuel injection device and the fuel injection method according to the first and sixth aspects of the invention , more fuel is injected into the intake port of which the air flow is relatively strong out of the two intake ports, The shape of the fuel spray toward each intake port of the fuel injection valve is long in the direction perpendicular to the direction in which the two intake ports are arranged, and each fuel spray is an umbrella of the intake valve interposed in each of the two intake ports. The fuel flow distribution in each fuel spray in the direction orthogonal to the direction in which the two intake ports are aligned is set so as to be directed to a position that is offset from the center of the part toward the side closer to the other intake valve. Peak values were shown on both sides of the line connecting the center of the valve umbrella.
According to the above invention, in the intake port having a relatively strong air flow, a large amount of fuel can be sufficiently atomized and vaporized, so that the fuel injection amount is larger than that in the intake port having a relatively weak air flow. Thus, sufficient atomization and vaporization performance can be maintained at each intake port.
In addition, since the spray shape is long in the direction orthogonal to the direction in which the intake ports are arranged, it is possible to inject fuel in a portion where the air flow is particularly strong in the intake ports, and the direction of spray is set to the other direction. By offsetting to the intake valve side of the intake port, it is possible to secure the distance between the portion of the intake port wall where the fuel adheres to the cylinder bore, and the fuel adhering to the intake port is sucked into the cylinder in a liquid state. It can be suppressed and the vaporization performance can be improved.
Further, by increasing the fuel flow rate on both sides of the center of the umbrella portion of the intake valve, it is possible to increase the concentration of the fuel to the portion where the intake flow is strong and to improve the vaporization performance.

Therefore, it is possible to reliably reduce the amount of HC in the exhaust while injecting the required amount of fuel.
In the present application, “injecting more fuel” means the ratio of the amount of fuel to be injected into the intake port having a relatively strong air flow to the intake port having a relatively weak air flow. It means to increase more than the proportion of fuel to be injected.

In the second aspect of the invention, the difference in air flow is caused by closing the air flow control valve. In the third aspect of the invention, the air flow between the intake ports generated by closing the air flow control valve is reduced. A swirl was generated in the combustion chamber due to the difference.
According to the above invention, the fuel injection amount for each intake port can be optimized to an amount that can ensure the vaporization performance, corresponding to the difference in the strength of the air flow between the intake ports generated to generate the swirl, As a result, the fuel spray can be sufficiently atomized and vaporized, while combustion can be stabilized by swirl generation in the combustion chamber.

According to the fourth and seventh aspects of the present invention, the fuel is 1.2 to 1.4 times that of the intake port having a relatively strong air flow compared to the amount of fuel injected to the intake port having a relatively weak air flow. Inject quantity.
According to the above invention, the ratio of the fuel injection amount to the intake port having a strong air flow and the intake port having a weak air flow can be optimized, and the fuel spray is vaporized to the maximum, thereby sufficiently reducing the HC amount in the exhaust gas. be able to.

According to the fifth and eighth aspects of the present invention, more fuel is injected into the intake port where the air flow is relatively strong, and fuel is injected more widely into the intake port where the air flow is relatively strong. .
According to the above-described invention, in the intake port where the air flow in which a lot of fuel is injected is relatively strong, by injecting the fuel in a wide range, the film thickness of the fuel adhering to the wall surface of the intake valve or the intake port can be reduced, Vaporization performance can be maintained.

Embodiments of the present invention will be described below.
FIG. 1 is a cross-sectional view of an internal combustion engine to which a fuel injection device, a fuel injection method, and a fuel injection valve according to the present invention are applied, and FIG. 2 is a top view of FIG.
In this embodiment, the cylinder axis direction is indicated by the Z axis, the arrangement direction of the intake valve and the exhaust valve is indicated by the Y axis, and the arrangement direction of the two intake valves is indicated by the X axis.

As shown in FIGS. 1 and 2, in the internal combustion engine 1, a piston 4 is inserted into a cylinder 3 formed in a cylinder block 2 so as to be able to reciprocate.
A cylinder head 5 is attached to the upper part of the cylinder 3, and a combustion chamber 11 is formed by the head of the piston 4 and the cylinder head 5.
A spark plug 12 is attached to the center of the cylinder head 5.

The cylinder head 5 is provided with two intake valves 6a and 6b and two exhaust valves 7a and 7b with the spark plug 12 as a center.
Intake ports 8a and 8b connected to the valve seats of the two intake valves 6a and 6b are formed in the cylinder head 5, and the intake ports 8a and 8b merge on the upstream side to form one intake port 8. To do.

A swirl control valve (airflow control valve) 9 for generating a swirl in the combustion chamber 11 is interposed upstream of the branch point of the intake port 8.
The swirl control valve 9 is a butterfly type on / off valve that is opened and closed by an actuator (motor or diaphragm) (not shown). As shown in FIG. 3, the swirl control valve 9 has a direction orthogonal to the cylinder axis and the central axis of the intake port 8 (X A valve body 9b having a notch is attached to a rotating shaft 9a supported so as to cross the opening of the intake port 8 in the axial direction).

FIG. 3 is a view of the swirl control valve 9 in the closed state from the direction of the arrow III shown in FIG. 2, that is, from the downstream side of the swirl control valve 9.
As shown in FIG. 3, the notch of the valve body 9b is formed on the cylinder head side (upper side) when the swirl control valve 9 is closed (when the valve body 9b is rotated to a position where the intake port 8 is shielded). And the position biased toward the intake port 8b (intake valve 6b) side is provided so as to partially open.

When the swirl control valve 9 is open, the valve body 9b is substantially parallel to the central axis of the intake port 8 so as to partition the opening of the intake port 8 in the cylinder axial direction.
When the swirl control valve 9 is closed, the intake air is biased toward the intake port 8b due to the notch of the valve body 9b, so that a swirl (lateral vortex) can be generated in the combustion chamber 11, and the swirl A homogeneous mixture is generated to improve combustion stability.

However, when the swirl control valve 9 is closed, the opening area of the intake passage is narrowed and the intake air is throttled, so that at high loads, the swirl control valve 9 can be opened to secure the cylinder intake air amount. To do.
A fuel injection valve 10 is attached above the intake port 8 upstream of the branch point of the intake port 8 (above the swirl control valve 9).

The fuel injection valve 10 is opened by lifting the valve body by an electromagnetic attraction force by an electromagnetic coil, and injects fuel (for example, gasoline) in two directions toward the intake valves 6a and 6b.
The fuel injected from the fuel injection valve 10 is sucked into the combustion chamber 11 through the intake valves 6a and 6b, ignited and burned by the spark ignition by the spark plug 12 in the combustion chamber 11, and pushes down the piston 4. Is generated.

The combustion gas in the combustion chamber 11 is discharged through the exhaust valves 7a and 7b, purified by an exhaust purification device (not shown), and then released into the atmosphere.
By the way, in the state where the swirl control valve 9 is closed, the intake air flows biased toward the intake port 8b (intake valve 6b) due to the notch of the valve body 9b, so the air flow rate (air flow) in the intake port 8b is The air velocity (air flow) at the intake port 8a is faster (stronger) (see FIG. 2).

  Here, when the fuel injection valve 10 injects the same amount of fuel into each of the intake ports 8a and 8b, the intake port 8b having a relatively fast air flow rate (strong air flow) causes fuel to flow due to a strong air flow. However, in the intake port 8a where the air flow rate is relatively slow (the air flow is weak), fuel atomization / vaporization is not promoted as compared to the intake port 8b side. turn into.

In other words, the intake port 8b, which has a relatively fast air flow rate (strong air flow), atomizes more fuel than the intake port 8a, which has a relatively slow air flow rate (weak air flow). It can be vaporized.
Therefore, in this embodiment, the amount of fuel injected to the intake port 8b side is larger than the intake port 8a side, and the fuel spray on the intake port 8b side is injected over a wider range than the intake port 8a side. Further, the injection characteristic of the fuel injection valve 10 is set.

In the present embodiment, the amount of fuel injection indicates the share of the required fuel injection amount, an amount exceeding half of the required injection amount is injected to the intake port 8b side, and an amount of fuel less than the remaining half is taken into the intake port. The injection characteristic of the fuel injection valve 10 is set so as to inject to the port 8a side.
If the amount of fuel injected to the intake port 8b side is increased, the amount of fuel injected to the intake port 8a side is relatively reduced, and even if the air flow rate is slow (air flow is weak), it is necessary and sufficient. While it is possible to achieve atomization / vaporization, the intake port 8b having a high air flow rate (strong air flow) has a high ability to promote atomization / vaporization, and therefore promotes atomization / vaporization for more fuel. It is possible to finely atomize and vaporize all of the fuel injected into the intake ports 8a and 8b.

On the intake port 8b side where more fuel is injected, the fuel is deposited over a wider range than the intake port 8a side, so that the film thickness of the fuel adhering to the umbrella portion of the intake valve 6b and the wall surface of the intake port 8b. The fuel vaporization performance on the intake port 8b side can be maintained.
The ratio of the amount of fuel injected to the intake port 8b side with respect to the amount of fuel injected to the intake port 8a side is such that the injection amount on the intake port 8b side is about 1.2 to 1.4, where the injection amount on the intake port 8a side is 1. It is preferable to set.

  As shown in FIG. 4, when the ratio of the injection amount is about 1: 1.2 to 1.4, a high vaporization rate can be maintained in both the intake port 8a and the intake port 8b, and the amount of HC in the exhaust gas is reduced to the maximum. However, if the injection amount on the intake port 8b side is increased more than 1.4 times, the air flow rate is fast (the air flow is strong), but the fuel amount exceeds the ability to atomize and vaporize and the vaporization rate is increased. It will decline.

On the other hand, if the ratio is less than 1.2 times, the injection amount on the intake port 8a side is relatively excessive and the vaporization rate as a whole is reduced.
Therefore, by setting the ratio of the injection amount to about 1: 1.2 to 1.4, it is possible to balance the vaporization rates at both intake ports 8a and 8b at a high level and to reduce the HC amount in the exhaust gas to the maximum. .

When the load is high, by opening the swirl control valve 9, the air flow velocity (intensity of air flow) in both the intake ports 8a and 8b becomes equal, and also at this time, more than the intake port 8b. However, when the load is high, the air flow rate is large and sufficient vaporization performance can be exhibited. Therefore, the vaporization rate does not deteriorate due to the difference in the fuel injection amount.
Next, the spray form in the fuel injection valve 10 will be described in detail.

  As shown in FIG. 5, the fuel spray injected toward the intake ports 8a and 8b (intake valves 6a and 6b) has a transverse cross section perpendicular to the direction in which the two intake ports 8a and 8b are arranged. The length of the fuel spray on the intake port 8b side in the longitudinal direction is longer than that on the intake port 8a side, and accordingly, the fuel spray on the intake port 8b side is injected over a wide range. It is supposed to be.

  The flow distribution in each fuel spray on the axis passing through the center of each fuel spray in a direction orthogonal to the direction in which the intake ports 8a and 8b are arranged is shown on both sides across the center as shown in FIG. 5 (d). The shape has a peak value, and the peak value of the flow rate in each fuel spray shows substantially the same level, but the fuel spray on the intake port 8b side injects fuel into a wider range on the axis, and the wall surface of the intake port 8b The amount of fuel injected to the intake port 8b side is set to be larger by injecting more fuel toward the intake port 8b.

Note that the peak value (P4, P6) in the flow rate distribution shown in FIG. 5 (d) is less than 8% of the total flow rate, so that the fuel concentration is lowered and the fuel film thickness is not excessively increased. It is preferable to do.
Further, the center of the fuel spray injected toward each intake port 8a, 8b is moved from the center of the umbrella portion of the intake valves 6a, 6b interposed in the two intake ports 8a, 8b to the other intake valve 6. It is set to point at a position offset to the near side.

The flow distribution on the axis connecting the centers of the intake valves 6a and 6b has two peak values (P1, P1) within a region sandwiched between the centers of the intake valves 6a and 6b, as shown in FIG. P3).
Note that the peak value (P1, P3) in the flow rate distribution shown in FIG. 5 (c) is less than 8% of the total flow rate, so that the fuel concentration is lowered and the fuel film thickness is not excessively increased. It is preferable to do.

When the swirl control valve 9 is closed, the air flow becomes stronger on the upper side of the intake port 8, and when the swirl control valve 9 is opened, the valve body 9b partitions the intake port 8 vertically, Since the air flow at the upper side and the lower side of the port becomes stronger, the shape of the cross section of each fuel spray is made longer in the direction perpendicular to the direction in which the intake ports 8a and 8b are arranged.
Further, if the fuel spray sprays directly against the inner wall of the intake port 8 at a position where the opening edge of the intake port 8a, 8b with respect to the combustion chamber 11 (the valve seat peripheral edge of the intake valve 6a, 6b) and the cylinder bore are close to each other, it is sufficiently vaporized. There is a possibility that the liquid fuel that could not be made is caught in the airflow in the cylinder as it is and the formation of a homogeneous air-fuel mixture is hindered.

Therefore, when the distance between the opening edge of the intake ports 8a and 8b with respect to the combustion chamber 11 and the cylinder bore becomes a predetermined value or more, the fuel spray is directed to the intake valves 6a and 6b so that the fuel spray directly hits the inner walls of the intake ports 8a and 8b. The center of the fuel spray is offset to the side close to the other adjacent intake valves 6a and 6b.
Here, the appropriate value of the spray angle of each fuel spray will be described with reference to FIG.

  First, as shown in FIGS. 6A, 6B, and 6C, the fuel spray spread angle (vertical spread angle) in the direction orthogonal to the direction in which the intake ports 8a, 8b are arranged is θ3, The angle formed by the center lines of the two fuel sprays respectively directed to the intake valves 6a and 6b is defined as θ1, and the spread angle (lateral spread angle) of each fuel spray in the direction in which the intake ports 8a and 8b are arranged is defined as θ2. An injection position of the fuel injection valve 10 is set as a base point, and an angle formed by a line connecting the base point and the centers of the two intake valves 6a and 6b is set as θbase.

In the fuel injection valve 10, the angles θ1 to θ3 and θbase are set so as to satisfy the following relationship.
・ Θ1: 85-95% of θbase
・ Θ2: 65 to 75% of θbase
-Θ3 on the intake port 8b side: 80 to 90% of θbase
-Θ3 on the intake port 8a side: 70 to 80% of θbase
By realizing the ratio of the angles θ1 to θ3 with respect to θbase, the spray is elongated in the direction orthogonal to the direction in which the intake valves 6a and 6b are arranged, the spray on the intake valve 6b side is longer, and the spray center is the other intake. The fuel spray shape offset to the valve 6 is realized, and the offset amount of the spray center and the range in which the fuel spray directly hits the intake port wall surface are set to values that can maximize the fuel spray vaporization performance. Will be.

Next, the structure of the fuel injection valve 10 that injects more fuel to the intake port 8b side than the intake port 8a side will be described in detail.
The fuel injection valve 10 includes a valve body that is lifted by a magnetic attractive force of an electromagnetic coil, and a nozzle plate that is provided on the downstream side of the seating surface of the valve body and has a plurality of injection holes opened. When the valve body is lifted by the magnetic attraction force of the electromagnetic coil and is opened, fuel is injected from the nozzle hole opened in the nozzle plate.

7 (a) and 7 (b) show opening patterns of the nozzle holes 52 opened to the nozzle plate 51, respectively, and are views of the nozzle plate 51 viewed from the upstream side. It is assumed that the fuel injection valve 10 is attached to the intake port 8 so that the intake ports 8a and 8b (intake valves 6a and 6b) are aligned.
7A and 7B, the plurality of nozzle holes 52 opened in the left half region 51a of FIG. 7 of the nozzle plate 51 inject fuel toward the intake port 8b (intake valve 6b). The plurality of nozzle holes 52 opened in the right half region 51b constitute a second nozzle hole group for injecting fuel toward the intake port 8b (intake valve 6b). The nozzle holes of each nozzle hole group have their opening axes set to achieve the above-described spray center and spray angle.

That is, fuel spray directed to the intake port 8b (intake valve 6b) is formed by the fuel injected from the injection holes 52 included in the first injection hole group, and is injected from the injection holes 52 included in the second injection hole group. Fuel spray is formed toward the intake port 8a (intake valve 6a) by the fuel.
Further, the number of nozzle holes 52 included in the first nozzle hole group in the left half in FIG. 7 of the nozzle plate 51 and the number of nozzle holes 52 included in the second nozzle hole group in the right half are respectively six. Although the number is the same, the diameter of the injection hole 52 of the first injection hole group is set larger than the diameter of the injection hole 52 of the second injection hole group, so that injection is performed toward the intake port 8b (intake valve 6b). The amount of fuel to be injected is set to be larger than the amount of fuel injected toward the intake port 8a (intake valve 6a).

  In addition, the nozzle holes 52 included in the first nozzle hole group and the nozzle holes 52 included in the second nozzle hole group are basically symmetrically arranged in a grid pattern, but are included in the second nozzle hole group. Among the nozzle holes 52, the opening positions of the nozzle holes 52a and 52b located on both ends in the direction orthogonal to the direction in which the intake ports 8a and 8b (intake valves 6a and 6b) are arranged are changed from the symmetrical positions to the nozzle plate 51. It is shifted toward the center.

As a result, the spray angle of the fuel spray toward the intake port 8a (intake valve 6a) in the direction perpendicular to the direction in which the intake ports 8a and 8b (intake valves 6a and 6b) are arranged is the intake port 8b (intake valve 6b). The fuel spray angle is narrower than the spray angle of the fuel spray toward.
In the nozzle plate 51 shown in FIG. 7A and the nozzle plate 51 shown in FIG. 7B, the lattice in which the nozzle holes 52 are arranged is the lattice in the vertical and horizontal directions in FIG. 7A. On the other hand, FIG. 7B is different in that it is an oblique 45 ° lattice.

Here, since the nozzle holes 52 are arranged in a grid pattern with respect to the nozzle plate 51, the spray pattern is uniformed, the dispersion of the particle diameter is eliminated, and the fuel vaporization performance can be improved.
However, the arrangement of the nozzle holes 52 in a grid pattern is not limited, and the number of the nozzle holes 52 included in each nozzle hole group is not limited. For example, the nozzle holes 52 are included in the first nozzle hole group. By increasing the number of injection holes 52 to be larger than the number of injection holes 52 included in the second injection hole group, the amount of fuel injected toward the intake port 8b (intake valve 6b) can be reduced. The amount of fuel injected toward the intake valve 6a) can be made larger.

In the above-described embodiment, two intake ports 8a and 8b are provided for one cylinder. For example, in an internal combustion engine provided with three intake ports for one cylinder, air is introduced between the intake ports. When there is a difference in the strength of the flow, more fuel can be injected into the intake port where the air flow is stronger.
The difference in the strength of the air flow includes not only the opening / closing of the airflow control valve such as the swirl control valve 9 but also the case where it occurs due to the difference in the opening area or shape of the intake port. In addition to an airflow control valve that generates a swirl, a case where an airflow control valve that generates a tumble flow (longitudinal vortex) is provided.

Further, the internal combustion engine may be a combination of an airflow control valve such as the swirl control valve 9 and a fixed rectifying plate that partitions the opening of the intake port.
Next, inventions other than those described in the claims that can be grasped from the above-described embodiment will be described together with the effects thereof.

(A) The fuel injection device for an internal combustion engine according to any one of claims 1 to 5, wherein a peak value in a fuel flow distribution in each fuel spray is set to less than 8% of a total flow rate. The fuel injection method for an internal combustion engine according to any one of claims 6 to 8 .

According to the above-described invention, it is possible to prevent the vaporization performance from deteriorating due to, for example, the fuel film adhering to the umbrella portion of the intake valve being thick due to excessive concentration of fuel injection.
(B) The airflow control valve is interposed upstream from the point where the airflow control valve branches into two intake ports, and the airflow is unevenly distributed to some intake ports in a closed state by a notch provided in the valve body. 3. The fuel injection device for an internal combustion engine according to claim 2, wherein a difference is produced in the strength of air flow between the two intake ports.

  According to the above invention, in the internal combustion engine that generates a vortex (for example, a swirl) in the combustion chamber by causing the air flow to drift to a part of the intake ports, the combustibility is improved by the generation of the vortex and the strength of the air flow is increased. By sharing the fuel amount according to the difference, the vaporization property of the fuel spray can be improved, and high combustion stability and reduction of the HC emission amount can be realized.

1 is a longitudinal sectional view of an internal combustion engine in an embodiment of the present invention. 1 is a top view of an internal combustion engine in an embodiment of the present invention. The front view which shows the swirl control valve in embodiment of this invention. The figure which shows the correlation with the ratio of the fuel flow volume, vaporization rate, and HC discharge | emission amount in embodiment of this invention. The figure which shows the flow volume distribution characteristic of the fuel spray in embodiment of this invention. The figure for demonstrating the setting of the spray angle of the fuel spray in embodiment of this invention. The figure which shows the arrangement | positioning pattern of the nozzle hole with respect to the nozzle plate in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Cylinder block, 3 ... Cylinder, 4 ... Piston, 5 ... Cylinder head, 6a, 6b ... Intake valve, 7a, 7b ... Exhaust valve, 8, 8a, 8b ... Intake port, 9 ... Swirl control Valve (air flow control valve), 10 ... Fuel injection valve, 11 ... Combustion chamber, 12 ... Spark plug, 51 ... Nozzle plate, 52 ... Injection hole

Claims (8)

And two intake ports provided for one cylinder provided with a fuel injection valve for injecting fuel to each of the two intake ports, a difference in the intensity of the air flow between the two intake ports An internal combustion engine fuel injection device in which
The fuel injection valve injects more fuel into the intake port where the air flow is relatively strong among the two intake ports ,
The shape of the fuel spray toward each intake port of the fuel injection valve is long in a direction orthogonal to the direction in which the two intake ports are arranged, and each fuel spray is an intake valve interposed in each of the two intake ports. Set to point at a position offset from the center of the umbrella to the side closer to the other intake valve, and
The flow rate distribution of the fuel in each fuel spray in a direction orthogonal to the direction in which the two intake ports are arranged shows a peak value on both sides across a line connecting the umbrella center of each intake valve . Fuel injection device. An airflow control valve for controlling a flow of air flowing through the two intake ports is provided, and the airflow strength is different between the two intake ports by closing the airflow control valve. Item 6. A fuel injection device for an internal combustion engine according to Item 1. 3. The fuel for an internal combustion engine according to claim 2, wherein a swirl flow is generated in the combustion chamber by causing a difference in strength of air flow between the two intake ports in a state where the air flow control valve is closed. Injection device.   The fuel injection valve has a fuel amount of 1.2 to 1.4 times that of the intake port with relatively strong air flow, compared to the amount of fuel injected into the intake port with relatively weak air flow. The fuel injection device for an internal combustion engine according to any one of claims 1 to 3, wherein injection is performed.   The fuel injection valve injects more fuel into the intake port where the air flow is relatively strong, and injects fuel more widely into the intake port where the air flow is relatively strong. The fuel injection device for an internal combustion engine according to any one of claims 1 to 4. There are provided two intake ports provided for one cylinder and a fuel injection valve for injecting fuel to each of the two intake ports, and the difference in air flow strength between the two intake ports In an internal combustion engine where
The fuel injection amount for each intake port by the fuel injection valve is set more for the intake port where the air flow is relatively strong,
The shape of the fuel spray toward each intake port of the fuel injection valve is long in a direction orthogonal to the direction in which the two intake ports are arranged, and each fuel spray is an intake valve interposed in each of the two intake ports. Set to point at a position offset from the center of the umbrella to the side closer to the other intake valve, and
The fuel flow rate distribution in each fuel spray in a direction perpendicular to the direction in which the two intake ports are arranged has a peak value on both sides of a line connecting the center of the umbrella portion of each intake valve. A fuel injection method for an internal combustion engine. 7. The fuel injection amount for the intake port having a relatively strong air flow is set to 1.2 to 1.4 times the fuel injection amount for the intake port having a relatively weak air flow. A fuel injection method for an internal combustion engine as described. The fuel is injected more into the intake port having a relatively strong air flow, and the fuel is injected in a wider range into the intake port having a relatively strong air flow. 8. A fuel injection method for an internal combustion engine according to claim 7 .

Images