JPH09217638A - Fuel injection device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To burn fuel in a stratified manner in a low quantitative fuel feed operation range by disposing an injection passage provided with a first injection hole pointing the direction of an ignition plug, and with a second injection hole pointing the direction separated from the ignition plug in a space between a fuel injection valve and a combustion chamber. SOLUTION: In a water cooling type two cycle engine 1, a scavenge port 21 is formed roughly at the center part in the axial direction of a cylinder bore 2c, and is communicated with a crank case 9 by way of a scavenge port 22. A accumulating type fuel injection valve 32 is mounted to a cylinder block 2 via an adapter 31, and an injection passage 32 is formed in the adapter 31, which is branched into a first injection port 41 pointing the direction of an ignition plug 14, and into a second injection port 42 pointing the direction of the apex face 5a of a piston. A infection direction variable valve 43 is disposed in a place close to a branching part in the bottom part of the second injection port 42, and the aforesaid valve 43 is so controlled that the quantitative rate of fuel from the first injection port 41 is increased in proportion in a low quantitative fuel feed operation area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for an internal combustion engine in which fuel is directly injected into a combustion chamber by a fuel injection valve.

[0002]

2. Description of the Related Art For example, in recent engines, stratified charge combustion is performed in a low load operation range and premixed uniform combustion is performed in a high load operation range in order to purify exhaust gas and improve fuel efficiency. Combustion control is performed. It is known that in this combustion control, it is effective to collect the fuel in the vicinity of the electrode of the spark plug during stratified combustion and to diffuse the fuel throughout the combustion chamber during premixed uniform combustion.

As a fuel injection device for an engine which performs such combustion control, there is conventionally known Japanese Patent Application Laid-Open No. 6-1067.
In Japanese Patent Laid-Open No. 4 (1994), an injection hole directed to the spark plug and an injection hole directed to the top surface of the piston are formed in the fuel injection valve, and the effective area of each injection hole is changed by changing the fuel pressure. Therefore, there has been proposed a configuration in which the fuel injection amount from each injection hole is controlled.

Further, Japanese Patent Application Laid-Open No. 4-103855 proposes one in which two fuel injection valves for stratified charge combustion and for premixed combustion are arranged in a combustion chamber.

[0005]

However, the structure in which two injection holes are formed in the fuel injection valve of the above-mentioned conventional publication has a problem that the degree of freedom of the injection timing is low, and the pressure accumulation type fuel injection valve is used. In such a case, the effective area of each injection hole is changed in the passage after the measurement, and therefore the measurement accuracy and the spray property (particle size) may be adversely affected.

Further, the structure using the two fuel injection valves of the above-mentioned conventional publication has a problem that the cost increases and the control method becomes complicated.

The present invention has been made in view of the above-mentioned conventional circumstances, and the degree of freedom of injection timing, the measurement accuracy, and the spray property can be improved while purifying exhaust gas and improving fuel efficiency.
Another object of the present invention is to provide a fuel injection device for an internal combustion engine that can reduce costs and simplify the control method.

According to a first aspect of the present invention, in a fuel injection device for an internal combustion engine equipped with a fuel injection valve for injecting fuel toward a combustion chamber, a spark plug direction is directed between the fuel injection valve and the combustion chamber. Of fuel from the first injection hole forming an injection passage including a first injection hole and a second injection hole directed in a direction away from the ignition plug, and occupying the total fuel amount in the low fuel amount supply operation range. Of the injection direction control means for changing the passage area of the second injection hole so that the ratio of the above is higher than the ratio in the high fuel supply operation range, and the start of fuel injection into the combustion chamber in the low fuel supply operation range. The timing is delayed from the start timing of fuel injection into the combustion chamber in the high fuel quantity supply operation range, and the end timing of fuel injection into the combustion chamber in the low fuel quantity supply operation range is set to the high fuel quantity supply operation range. It should be the same timing as the end of fuel injection into the chamber It is characterized in that a fuel injection timing control means for controlling the fuel injection timing so that.

According to a second aspect of the present invention, in a fuel injection device for an internal combustion engine equipped with a fuel injection valve for injecting fuel toward a combustion chamber, a spark plug direction is directed between the fuel injection valve and the combustion chamber. Of fuel from the first injection hole forming an injection passage including a first injection hole and a second injection hole directed in a direction away from the ignition plug, and occupying the total fuel amount in the low fuel amount supply operation range. The injection direction control means for changing the passage area of the second injection hole so that the ratio of the fuel injection amount is higher than the ratio in the high fuel amount supply operating range, and the injected fuel causes spark injection plugs at least in the low fuel amount supply operating range when a spark occurs. An injection timing control means for controlling the fuel injection timing so as to pass the vicinity is provided.

According to a third aspect of the present invention, in a fuel injection device for an internal combustion engine having a fuel injection valve for injecting fuel toward a combustion chamber, a spark plug direction is directed between the fuel injection valve and the combustion chamber. Of the fuel amount from the first injection hole in the high fuel amount supply operation range by forming an injection passage including a first injection hole and a second injection hole that is directed in a direction away from the ignition plug. Sometimes the fuel injection start timing in the high fuel amount supply operating range is set to the low fuel supply operating range so that the proportion of the fuel amount that has completed passing through the vicinity of the spark plug becomes larger than that in the low fuel supply operating range. It is characterized in that it is provided with an injection timing control means for advancing the fuel injection start timing in the above.

According to a fourth aspect of the present invention, in the first or second aspect, the fuel injection valve is mounted on an adapter inserted and fixed in the vicinity of the combustion chamber on the side wall of the cylinder block. It is characterized in that an injection passage including the second injection hole is formed.

According to a fifth aspect of the present invention, in any one of the first to third aspects, an air mixing portion is formed in the middle of the injection passage, and an air supply passage is connected to the air mixing portion to connect the air supply portion. The first and second air-fuel mixture atomized in the mixing section
It is characterized in that it is configured so as to be injected and supplied from the injection holes into the combustion chamber.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 to FIG.
5 is a view for explaining a fuel injection device of a two-cycle engine according to an embodiment of the invention of FIGS. 1 to 5, FIG. 1 is a configuration diagram showing the fuel injection device of the engine, FIG. 2 is a sectional view of the engine, and FIG. FIG. 4 is a diagram showing the relationship between the combustion chamber pressure and the crank angle, FIG. 5 is an injection timing diagram, and FIG. 6 is a relationship between the injection direction variable valve opening and the fuel injection amount. It is a characteristic view to show.

In the figure, reference numeral 1 denotes a water-cooled two-cycle engine having a structure in which a crankcase 3 is fastened and fixed to a lower mating surface 2a of a cylinder block 2 and a cylinder head 4 is fastened to an upper mating surface 2b. In the cylinder bore 2c of the cylinder block 2, a piston 5
Is slidably inserted. A small end 6a of a connecting rod 6 is connected to the piston 5 via a piston pin 7 and a needle bearing 8, and a large end 6b of the connecting rod 6 is arranged in a crank chamber 9 of the crankcase 3. It is connected to a crank pin 11 of the crank shaft 10 via a needle bearing 12.

A combustion recess 4a is provided in a portion of the lower surface of the cylinder head 4 facing the cylinder bore 2c, and a space surrounded by the combustion recess 4a, the cylinder bore 2c, and the top surface 5a of the piston 5 is burned. It is room 13. A spark plug 14 is mounted on the cylinder head 4 with its electrode portion 14a protruding into the combustion recess 4a.

The crankcase 3 has a structure in which an upper case 3a and a lower case 3b are vertically divided into two, and an intake opening 15 communicating with the crank chamber 9 is formed in the lower case 3b.
Are formed. An intake passage 16 is connected to the intake opening 15, and an air cleaner 17 is connected to an upstream end of the intake passage 16.

A reed valve 18 as a check valve is arranged in the intake opening 15. This reed valve 18
Has a structure in which an opening 18b formed in the valve body 18a is opened and closed by a valve plate 18c.
When the inside of the crank chamber 9 becomes a negative pressure due to the rise, the air is automatically introduced to introduce the air, and when the inside becomes a positive pressure, the air is closed to prevent the blowback of the air. A throttle valve 19 is arranged upstream of the reed valve 18 in the intake passage 16, and the intake air amount is adjusted by the opening of the throttle valve 19. An air flow meter 20 is arranged between the throttle valve 19 and the air cleaner 17.

Cylinder bore 2 of the cylinder block 2
A scavenging port 21 is formed at a substantially central portion in the axial direction of c,
The scavenging port 21 includes the cylinder block 2 and the upper case 3.
It communicates with the crank chamber 9 through the scavenging port 22 formed in a. Also, the scavenging port 2 of the cylinder block 2
An exhaust port 23 is formed in a portion facing 1 and an exhaust passage (not shown) is connected to the exhaust port 23.

An exhaust timing variable valve 24 is disposed on the upper wall portion of the opening of the exhaust port 23. The exhaust timing variable valve 24 is formed by cutting a part of a round bar to form a substantially arcuate valve portion 24a, and the valve portion 24a is recessed in the ceiling wall of the exhaust port 23 and The most advanced angle position (see the solid line in FIG. 2) that is flush with the inner surface of the exhaust port 23, and the most retarded position (see the chain double-dashed line in FIG. 2) where the valve portion 24a protrudes and slightly narrows the opening of the exhaust port 23. The exhaust timing is changed by continuously rotating between the intervals.

The exhaust timing variable valve 24 is controlled to open / close by the CPU 25 via a drive motor (not shown). The CPU 25 controls the turning angle of the exhaust timing variable valve 24 via a turning drive device (not shown) according to operating conditions such as throttle opening and engine speed. For example, in the low-speed operation range, the exhaust start timing is delayed by closing the valve fully, and the opening is increased to advance the exhaust start time from the low-speed range to the medium / high-speed operation range. It suppresses the output decrease.

The engine 1 has a fuel injection device 30.
Are arranged. The fuel injection device 30 is mainly composed of an adapter 31 arranged in the cylinder block 2 and a pressure accumulation type fuel injection valve 32 mounted on the adapter 31.

Exhaust port 23 of the cylinder block 2
A mounting hole 2d that is open to the inside of the cylinder bore 2c is formed on the opposite side to the upper wall portion, and the adapter 31 is airtightly inserted and fixed in the mounting hole 2d through the seal members 33 and 34. ing. A mounting recess 31a is provided in the adapter 31, and the injection portion 32a of the fuel injection valve 32 is mounted in the mounting recess 31a.
Incidentally, 35 is a seal member, 36 is a fuel rail connected to the fuel supply portion 32b of the fuel injection valve 32, and a fuel pump (not shown) is connected to the fuel rail 36.

The fuel injection valve 32 has an injection case 32c.
A valve body (not shown) that opens and closes the injection port 32d is disposed in the closed side while being constantly biased by a return spring, and the valve body is opened by an electromagnetic coil to open the injection port 32d. This is a schematic structure for injecting an amount of fuel according to the open period.

The adapter 31 is formed with an injection passage 40 having a circular cross section extending in the axial direction from the bottom surface of the mounting recess 31a, and the injection passage 40 is directed toward the electrode portion 14a of the ignition plug 14. It is branched into an injection hole 41 and a second injection hole 42 that points in the direction of the top surface 5a of the piston 5. The inner diameter of the second injection hole 42 is equal to that of the first injection hole 4
It is set larger than the inner diameter of 1.

An injection direction variable valve 43 as an injection direction control means for changing the opening area of the second injection hole 42 is arranged near the branch portion at the bottom of the second injection hole 42, The injection direction variable valve 43 is inserted and arranged so as to cross the second injection hole 42 of the adapter 31 in the crankshaft direction.

The variable injection direction valve 43 has a structure in which a valve portion 43a having a substantially arcuate shape when viewed in the injection hole axial direction is formed by cutting out a part of a round bar.
Is fully inserted into the bottom of the second injection hole 42 and is flush with the inner surface of the bottom (see the solid line in FIG. 3), and the valve portion 43a.
Is projected to the inside of the injection hole and is rotated between the fully closed position (see the chain double-dashed line in FIG. 3) that closes the second injection hole 42.

A rotational drive mechanism (not shown) is connected to the outward protruding end of the injection direction variable valve 43, and the drive mechanism functions as the fuel injection timing control means.
Is driven and controlled. Here, either an electronic actuator or a mechanical actuator can be adopted as the rotation drive mechanism.

The adapter 31 has an injection passage 40.
Is formed in the direction perpendicular to the axis, and a confluence portion between the air supply passage 44 and the injection passage 40 is an air mixing portion. The air supply passage 44 is led out to the outside via an air passage 45 formed between the mounting hole 2d of the cylinder block 2 and the adapter 31. One end of an air supply pipe 46 is connected to the outlet of the air passage 45, and the other end is connected to a discharge port 47a of an air pump 47 that is rotationally driven via the crankshaft 10. A relief valve 48 is connected to the upstream end of the air supply pipe 46, and a check valve 49 is provided midway on the downstream side.

The air pump 4 is connected to the air mixing section.
7, the air pressure C is constantly added, and the air pressure C is set lower than the fuel injection pressure B. In addition to the air pump 47, the air pressure source to the air mixing section stores air pressure generated in the engine in an accumulator,
The accumulated air pressure may be used.

The CPU 25 uses the air flow meter 2
0, the throttle opening sensor 50, the engine speed sensor 51, and the engine cooling water sensor 52 are input, and an ignition signal is sent to the ignition circuit 70 for generating an ignition spark in the ignition plug 14 according to the engine operating state. To
A drive control signal is sent to the exhaust timing variable valve 24, and the fuel injection valve 32
And a drive control signal to the injection direction variable valve 43, respectively.

FIG. 4 is a characteristic diagram showing the relationship between the combustion chamber pressure and the crank angle. The air supply pressure A is substantially constant, but the combustion chamber pressure (cylinder bore pressure) C changes greatly depending on the compression stroke, ignition stroke, and exhaust scavenging stroke. The fuel cannot be injected into the combustion chamber 13 during the period T3 in which the injection hole is blocked by the piston 5. When the fuel injection pressure D of the fuel injection valve 32 is higher than the air supply pressure A, it becomes possible to inject fuel into the injection passage 40 during the period T3.

When fuel is injected during the period ti in the figure,
The pressure B in the injection passage 40 rises during the injection period and is kept constant by the action of the check valve 49 as the injection is stopped.
The fuel that is to be injected and stays in the injection passage 40 is heated by the heat of the surroundings.

When the injection hole 41 is opened, the combustion chamber C
Is high, the burned gas enters from the injection hole 41 to increase the pressure, and the fuel is further heated by receiving heat from the burned gas. The pressure B in the injection passage 40 is the combustion chamber pressure C.
It is injected into the combustion chamber 13 in a larger state and immediately vaporized. With the passage of time, the combustion chamber pressure C becomes the air supply pressure A.
It becomes lower and the pressure B in the injection passage 40 becomes equal to the air supply pressure A, so that the fuel is pushed by the air and the combustion chamber 1
It is injected while being miniaturized within 3.

During the period T1 in which the air supply pressure A becomes larger than the combustion chamber pressure C, air is supplied into the combustion chamber 13 through the injection holes 41 and 42. Although not shown, when fuel is injected from the injection portion 32a of the fuel injection valve 32 during this period, it is immediately injected into the combustion chamber 13 together with air. The fuel is further atomized in the combustion chamber 13 by the action of the air flow, and atomization and vaporization are promoted. When the injection portion 32a is decompressed by the air flow and a pressure lower than the air supply pressure A acts, the fuel injection pressure D may be lower than the air supply pressure A.

The period in which the combustion chamber C is higher than the air supply pressure A and the injection hole 41 is not blocked by the piston 5 (T
(2, T4), when the fuel injection pressure D is higher than the combustion chamber pressure C, although not shown, as soon as fuel is injected from the injection portion 32a of the fuel injection valve 32 during this period, the injection passage 40 Then, the fuel is injected into the combustion chamber 13.
In this case, only fuel is injected into the combustion chamber 13.

FIG. 5 shows an embodiment in which fuel injection in all operating states is carried out during a period T1 in which the air supply pressure A is lower than the combustion chamber pressure C. At the same time as the beginning T3S of the period T1, the fuel injection at the time of high load (high fuel amount supply operation range) in which the fuel supply amount per combustion cycle is large (IS (high))
However, when the amount of fuel commensurate with the load is supplied into the injection passage 40, the injection from the fuel injection valve 32 ends (IE
(High)) As described above, the fuel supplied into the injection passage 40 is atomized and injected into the combustion chamber 13 together with the air flow. At the time of high load, fuel is injected into the combustion chamber 13 at an early stage together with the air flow, so that the combustion chamber 1 is ignited before ignition.
A more uniform air-fuel mixture can be formed in 3 and a high output can be obtained. This combustion is so-called premixed combustion.

In a low load (low fuel amount supply operation range) where the fuel supply amount per combustion cycle is small, as shown in the figure, fuel injection starts at Is (low) and ends at IE (low). The fuel injection is performed as late as possible during the period T1 and is mainly performed from the first injection holes 41 as described below. Therefore, the fuel injected into the combustion chamber 13 through the injection passage 40 is ignited. When the spark is generated, the injected fuel is directed toward the plug 14 and passes through the vicinity of the spark plug 14. Therefore, a rich air-fuel mixture is formed in the vicinity of the spark plug 14, and a portion farther from the spark plug 14 becomes a lean air-fuel mixture, so that stratified combustion is achieved and stable and low exhaust emission combustion is possible.

Even when the injected fuel has completed passing through the vicinity of the spark plug 14 at the time of spark generation, and in the intermediate load range close to the full load, the injection start timing (IS (medium)) is the same as the high load. , Advance the injection end timing (IE (medium)) according to the injection amount. Further, by increasing the fuel injection pressure D,
The injection start timing at high load (IS (high)) may be set to T4 period, and the injection end timing at low load (IE (low)) may be set to T2 period.

Even when the fuel supply amount per combustion cycle is small and the load is low, the external load may be small and the rotation may be high. In the case of this high speed / low load, the fuel supply amount per hour is larger than that in the case of low speed / low load, and there are cases where fuel consumption or low exhaust emission can be obtained by premixed combustion rather than by stratified combustion. In this case, the injection may be performed at the timing of I '(low) in the figure.

As shown in FIG. 6, the CPU 25 controls the opening degree of the injection direction variable valve 43, that is, the passage area of the second injection hole 42 according to the operating range (fuel injection amount) of the engine. Thus, the ratio of the amount of fuel from the first injection hole 41 to the total amount of fuel is controlled. As is clear from the figure,
The above opening is fully closed in the low speed rotation / low load range (low fuel amount supply operation range), and is continuously closed until the high speed rotation / high load range (high fuel amount supply operation range). Increase.

As a result, in the low fuel amount supply operation region, the ratio of the fuel amount from the first injection hole 41 to the total injected fuel amount becomes larger than that in the high fuel amount supply operation region, especially during idling. In an extremely low fuel supply operating range such as
All of the injected fuel is injected and supplied into the combustion chamber 13 from the first injection hole 41 toward the ignition plug. As a result, the fuel concentrates near the electrode 14a of the spark plug 14 in the operating region where the absolute value of the amount of fuel supplied into the combustion chamber 13 is small.

In the low fuel amount supply operation region, the fuel injection timing is retarded to the ignition timing side as described with reference to FIG. 5, so that the injected fuel sparks in the low fuel amount supply operation region. When it occurs, it will pass near the electrode 14a of the spark plug 14.

As described above, in the low fuel amount supply operation range, the injected fuel is concentrated around the electrode 14a of the ignition plug 14, and the ignition is performed at the timing when the fuel passes through the electrode 14a portion. Therefore, so-called stratified charge combustion can be stably and reliably performed.

Further, in the high fuel amount supply operation region, the passage area of the second injection hole 42 is larger than that of the first injection hole 41, so that the fuel amount from the second injection hole 42 occupies the total fuel amount injected. The ratio becomes larger than that in the low fuel amount supply operation region, and particularly in the high speed / high load operation region, most of the injected fuel is injected and supplied into the combustion chamber 13 through the second injection hole 42.

In the high fuel amount supply operation range, the fuel injection timing is advanced as described with reference to FIG.
Of the fuel quantity from the first injection hole 41, the proportion of the fuel quantity that has completed passing through the vicinity of the electrode 14a of the spark plug 14 by the time the spark is generated is larger than that in the low fuel quantity supply operation range, that is, high. In the fuel amount supply operation region, the injected fuel is uniformly diffused in the entire combustion chamber 13, and so-called premixed uniform combustion can be reliably performed.

As described above, in this embodiment, the fuel injection valve 3
An injection passage 40 having a first injection hole 41 directed to the ignition plug 14 and a second injection hole 42 directed to the top surface 5a of the piston 5 is formed in the adapter 31 to which 2 is attached, and the second injection is performed. Since the injection direction variable valve 43 for changing the passage area of the hole 42 is arranged in the hole 42, the injection direction variable valve 4 is operated in a low fuel amount supply operation region such as a low speed / low load operation region.
By closing No. 3, fuel can be collected around the ignition plug 14, and combustion stability by stratified combustion and fuel consumption can be improved.

Further, in the low fuel amount supply operation range, the fuel injection timing is controlled so that a spark is generated when the fuel passes through the electrode 14a portion of the spark plug 14, so from this point as well, stratified charge combustion is surely performed. It can be carried out.

Further, the opening degree of the injection direction variable valve 43 is increased and the fuel injection timing is set to the first by the ignition timing toward the high fuel amount supply operation area such as the high speed / high load operation area.
By advancing so that most of the fuel from the injection hole 41 passes through the spark plug, the fuel can be diffused uniformly throughout the combustion chamber, and stable combustion with high combustion efficiency by premixed uniform combustion can be obtained. The output can be improved.

Since the adapter 31 is arranged in the portion of the upper wall of the cylinder block 2 facing the combustion chamber 13, the fuel injected during the compression / combustion stroke of the piston 5 can be stored as described above, and that much fuel can be stored. The degree of freedom in setting the injection timing can be improved, and the required fuel amount at the time of high load can be secured. In addition, it is possible to eliminate concerns about weighing accuracy and spray properties due to changes in cross-sectional area after weighing.

Since the first and second injection holes 41 and 42 are formed in the adapter 31 to which the fuel injection valve 32 is attached,
Only one injection / injection valve needs to be arranged in one cylinder, and the cost can be reduced and the control can be simplified by the smaller number of injection valves as compared with the case of disposing two conventional fuel injection valves.

Since the air supply passage 44 is communicatively connected to the injection passage 40 of the adapter 31, while the valve 43 for changing the passage area is provided in the second injection hole 42, the spray property of the fuel is
It is possible to suppress adverse effects on the measurement accuracy and obtain stable combustion from the low speed range to the high speed range. By the way, when the area of the injection passage located on the downstream side of the metering portion is variably controlled, there is a concern that the metering accuracy and the spray property may be adversely affected, but in the present embodiment, the fuel is atomized by compressed air. Since the so-called air assist is performed, the above concern can be resolved.

Further, since the air assist is performed, the fuel pressure can be lowered. Therefore, it becomes possible to divert the low-pressure injection system configured to inject fuel into the conventional intake pipe.

In the above embodiment, the case where the air pressure is constantly supplied to the injection passage 40 has been described, but the present invention is an air injection valve for controlling the injection timing of the compressed air in the middle of the air supply pipe 46. , Fuel injection precedes,
The compressed air may be supplied into the combustion chamber at an appropriate time during the above-mentioned effective fuel injection period.

FIG. 7 shows an example of a so-called precharge system in which fuel injection is preceded. In this case, the fuel injection pressure D is changed to the air supply pressure A in the high fuel amount supply operation range.
Fuel is injected into the injection passage 40 at a higher temperature, the injection holes 41 and 42 are opened, and the fuel injection into the combustion chamber 13 is started from the time when the injection passage 40 pressure B becomes higher than the combustion chamber pressure A. I will let you.

By advancing the injection timing to the injection passage 40 to I1 (high), the temperature of the fuel staying in the injection passage 40 can be raised, and after the injection into the combustion chamber 13, The vaporization of can be promoted.

By delaying the injection timing to the injection passage 40 as I3 (high), the temperature of the fuel is raised and the injection passage 4
The vaporization in the combustion chamber can be further promoted by both the atomization of the fuel by the fuel injection into the flowing air flow at 0.

In any case, the fuel is actually supplied from the injection passage 40 into the combustion chamber 13 at the timing of I '(high) in the figure. That is, fuel injection into the combustion chamber 13 is started from the time when the injection holes 41 and 42 are opened and the injection passage 40 pressure B becomes higher than the combustion chamber pressure C, and the entire injection amount is supplied into the combustion chamber 13. Then, the fuel injection into the combustion chamber 13 ends.

On the other hand, in the low fuel amount supply operation region, I
Regardless of whether the injection is 1 (low) or I2 (low), both the injection start timing and the injection end timing are delayed from I '(high) in the high fuel amount supply operation range, or the injection end timing is Same timing. In addition to the large injection ratio from the injection holes 41, a rich mixture can be formed in the vicinity of the spark plug 14 at the time of ignition, so stratified combustion itself or combustion close thereto can be performed.
It is possible to achieve reduction of fuel consumption or exhaust emission in the low fuel amount supply operation range. I1 rather than I2 (low)
(Low) facilitates stratified combustion. This is because the fuel will pass near the spark plug 14 during ignition.

In the above embodiment, the case where the opening degree of the injection direction variable valve 43 is continuously changed has been described. However, in the present invention, as shown in FIG. 8, the engine load and the intake pipe negative pressure are changed. The opening degree of the injection direction variable valve may be controlled to be switched in two stages, or may be controlled to be switched in three stages or more.

Further, in the above-mentioned embodiment, the two-cycle engine is taken as an example, but the present invention is naturally applicable to a four-cycle engine and further applicable to a case where the fuel injection valve is mounted on the cylinder head side. . Furthermore, in the above-described embodiment, the air supply space 46 is connected to the injection passage 40 via the check valve 49, but the air supply pipe 46 may be disconnected. In this case as well, the method of injecting fuel from the fuel injection valve 32 can employ any of the methods shown in FIGS. Although the fuel cannot be atomized by the air flow and only the fuel is injected, the premixed combustion in the high fuel amount supply operation region and the stratified combustion itself in the low fuel amount supply operation region by the operation of the injection direction variable valve 43, Alternatively, combustion close to that becomes possible.

[0061]

As described above, according to the fuel injection device for an internal combustion engine according to the first and second aspects of the present invention, the first injection port oriented in the spark plug direction is provided between the fuel injection valve and the combustion chamber. An injection passage having a second injection hole directed in a direction away from the ignition plug is provided, and in the low fuel amount supply operation region, the first injection hole is provided.
Since the passage area of the second injection hole is changed so that the ratio of the fuel amount from the injection hole is higher than that in the high fuel amount supply operation region, stratified charge combustion can be reliably performed in the low fuel amount supply operation region. It also has the effect of improving exhaust gas purification and fuel consumption.

Further, in the low fuel amount supply operation range, the fuel injection timing is controlled so that the spark is generated at the timing when the fuel passes near the spark plug, and further the injection end timing is delayed. Also, stratified charge combustion can be reliably performed.

According to the third aspect of the present invention, in the high fuel amount supply operation region, the proportion of the fuel from the first injection hole that has completed passing through the vicinity of the spark plug by the spark generation timing is lower than that in the low fuel amount supply operation region. Since the fuel injection start timing is advanced so as to increase the amount, the fuel is uniformly dispersed in the combustion chamber, the premixed combustion can be reliably performed, the combustion becomes good, and the output can be improved.

In the invention of claim 4, the adapter is inserted and fixed to the side wall of the cylinder block, and the first and second adapters are attached to the adapter.
Since the injection hole is branched and the passage area of the second injection hole can be variably controlled, a desired amount of fuel can be injected and supplied in different directions by one fuel injection valve, and the number of parts can be reduced and the control can be performed. There is an effect that it can be simplified and the cost can be reduced.

According to the fifth aspect of the invention, since the air supply passage is connected to the injection passage so that the fuel is atomized by the air assist, the fuel can be atomized while the passage area variable valve is provided in the middle of the injection hole. It has the effect of improving the metering accuracy and spraying properties, and being able to obtain stable combustion from the low speed range to the high speed range.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram for explaining a fuel injection device for a two-cycle engine according to an embodiment of the present invention.

FIG. 2 is a sectional view of the engine.

FIG. 3 is an enlarged cross-sectional view of essential parts of a fuel injection passage and an injection hole portion of the engine.

FIG. 4 is a combustion chamber pressure-crank angle characteristic diagram of the fuel injection device.

FIG. 5 is a diagram showing a fuel injection timing of the fuel injection device.

FIG. 6 is a characteristic diagram showing the relationship between the injection direction variable valve opening and the injection injection amount of the fuel injection device.

FIG. 7 is a diagram showing an injection timing according to a modified example of the above embodiment.

FIG. 8 is a characteristic diagram showing the relationship between the injection direction variable valve opening and the intake pipe negative pressure according to a modified example of the above embodiment.

[Explanation of symbols]

1 2 cycle engine 2 cylinder block 13 combustion chamber 14 spark plug 25 CPU (injection timing control means) 30 fuel injection device 31 adapter 32 fuel injection valve 40 injection passage 41 first injection hole 42 second injection hole 43 injection direction variable valve ( Injection direction control means) 44 Air supply passage

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02M 61/18 340 F02M 61/18 340E

Claims (5)

[Claims] 1. A fuel injection device for an internal combustion engine, comprising a fuel injection valve for injecting fuel toward a combustion chamber, wherein a first injection hole is provided between the fuel injection valve and the combustion chamber and oriented in a spark plug direction. And a second injection hole directed in a direction away from the spark plug, forming an injection passage, and the ratio of the fuel amount from the first injection hole to the total fuel amount in the low fuel amount supply operation region is high. The injection direction control means for changing the passage area of the second injection hole so as to be larger than the ratio in the fuel quantity supply operation range, and the injection start timing of the fuel into the combustion chamber in the low fuel quantity supply operation range to the high fuel quantity. The fuel injection to the combustion chamber in the supply operation range is delayed from the start time, and the injection end time of the fuel to the combustion chamber in the low fuel amount supply operation range is delayed. Fuel injection to be the same or delayed as the injection end timing A fuel injection device for an internal combustion engine, comprising: injection timing control means for controlling the timing. 2. A fuel injection device for an internal combustion engine, comprising a fuel injection valve for injecting fuel toward a combustion chamber, wherein a first injection hole directed between the fuel injection valve and the combustion chamber in a spark plug direction. And a second injection hole directed in a direction away from the spark plug, forming an injection passage, and the ratio of the fuel amount from the first injection hole to the total fuel amount in the low fuel amount supply operation region is high. Injection direction control means for changing the passage area of the second injection hole so as to be larger than the ratio in the fuel supply operation range, and for injecting fuel to pass near the spark plug at the time of spark generation at least in the low fuel supply operation range. And a fuel injection timing control means for controlling the fuel injection timing. 3. A fuel injection device for an internal combustion engine, comprising a fuel injection valve for injecting fuel toward a combustion chamber, wherein a first injection hole oriented between the fuel injection valve and the combustion chamber in a spark plug direction. An injection passage including a second injection hole directed in a direction away from the spark plug, and a portion of the fuel amount from the first injection hole in the high fuel amount supply operation region is provided near the spark plug when a spark occurs. The fuel injection start timing in the high fuel quantity supply operation area is set to the fuel injection start timing in the low fuel quantity supply operation area so that the proportion of the fuel quantity that has completed passing is greater than the proportion in the low fuel quantity supply operation area. A fuel injection device for an internal combustion engine, comprising: an injection timing control means that is earlier than the timing. 4. The fuel injection valve according to claim 1, wherein the fuel injection valve is attached to an adapter inserted and fixed near a combustion chamber on a side wall of a cylinder block, and the adapter is provided with the first and second injection holes. A fuel injection device for an internal combustion engine, wherein an injection passage including the injection passage is formed. 5. The fog in the air mixing portion according to claim 1, wherein an air mixing portion is formed in the injection passage and an air supply passage is connected to the air mixing portion. A fuel injection device for an internal combustion engine, characterized in that the changed air-fuel mixture is injected and supplied into the combustion chamber from the first and second injection holes.