JPH07167016A - Fuel injection device - Google Patents

Abstract

PURPOSE:To form a lean mixture combustion area in an early time, and thereby improve exhaust gas by forming a plurality of fine injection holes at each injection position in the fuel injection device which is so designed to inject pressurized fuel in a mist condition. CONSTITUTION:In a fuel injection nozzle, fuel is injected out of an injection port 35 formed at the tip end of an injection nozzle main body 34 toward a combustion chamber at the apex of a piston so as to be formed in fuel spray, the fuel spray is naturally ignited due to heat by compressed intake air, and it is then burnt out. In this place, for example, six injection places are set at the nozzle main body 45, and three fine injection ports 35 to each place are formed. Namely, three fine injection ports 35 roughly 10 to 150mum in diameter each are to be formed in the diameter of a former injection port. By this constitution, the total area of the injection ports is lessened, fuel pressure at the time of injection is thereby boosted up, and concurrently a lean mixing area is formed by mutual turbulence, so that ignition performance is improved.

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, and more particularly to a fuel injection device which atomizes pressurized fuel and injects it.

[0002]

2. Description of the Related Art In a diesel engine, the intake air is compressed to a high temperature state by moving the piston to the top dead center side, and fuel is injected in synchronization with the piston reaching almost the top dead center. Then, the fuel spray is spontaneously ignited by the heat of the intake air to perform combustion. Therefore, the diesel engine is equipped with a fuel injection pump or a unit injector, and the fuel is pressurized by the fuel injection pump or the unit injector,
The fuel is injected into the cylinder from the fuel injection nozzle or the injection port of the unit injector.

The fuel injection nozzle for injecting fuel in this way is provided with a plurality of, for example, 3 to 8 injection holes on its tip side. Each nozzle has a diameter of 0.2-0.6 mm
And has a size such that fuel is injected through these nozzles.

[0004]

When timing retardation is carried out in order to improve the exhaust gas of the fuel, especially to reduce the nitrogen oxides in the exhaust gas, conversely the ignition delay becomes remarkable and the nitrogen oxides increase or misfire occurs. Or occur.
In order to prevent such ignition delay and misfire,
It is possible to improve the mixing range of fuel and air. Therefore, we are trying to improve the injection system to perform high pressure injection, to make the shape of the combustion chamber a reentrant type, to strengthen the disturbance of intake air by the intake port, etc. Measures are reaching their limits.

The present invention has been made in view of the above problems, and a lean mixed combustion region is formed early so that the ignitability can be improved even if a timing retard is performed. An object of the present invention is to provide a fuel injection device designed to be improved.

[0006]

SUMMARY OF THE INVENTION According to the present invention, in a fuel injection device in which pressurized fuel is atomized and injected, a plurality of fine injection holes are formed at each injection position. The present invention relates to a characteristic fuel injection device.

[0007]

When the fuel is pressurized, the pressurized fuel is supplied to the fuel injection device and simultaneously injected from a plurality of fine injection holes formed at respective injection positions on the tip side thereof.

[0008]

1 shows a main part of a diesel engine equipped with a fuel injection device according to an embodiment of the present invention, in which a cylinder block 10 is provided with a cylinder 11 consisting of a through hole. A piston 12 is slidably arranged in the cylinder 11. The piston 12 is connected to the connecting rod 14 by a piston pin 13.

The upper opening of the cylinder 11 is closed by a cylinder head 15, and the cylinder head 15 has an intake port 16 and an exhaust port 1.
7 and 7 are formed respectively. These intake ports 1
6 and the exhaust port 17 are opened and closed by an intake valve 18 and an exhaust valve 19, respectively. A fuel injection nozzle 20 is attached to the cylinder head 15 so as to inject fuel toward a combustion chamber 21 formed on the top surface of the piston 12.

The fuel injection nozzle 20, as shown in FIG.
It is connected to the corresponding pump unit 26 of the column fuel injection pump 25 by the injection pipe 24. The fuel injection pump 25 includes a mechanical governor 27, and the mechanical governor 27 moves a control rack 28 to
The amount of fuel that is injected each time is adjusted. The fuel injection pump 25 includes a cam shaft 29, and a cam 30 attached to the cam shaft 29.
Drive each pump unit 26.
A timer 31 is provided on the camshaft 29, and the timing of injection is adjusted by the timer 31.

The fuel injection nozzle 20, as shown in FIG.
The tip portion is composed of a nozzle body 34, and a plurality of injection holes 35 are formed at each of the injection positions of the tip portion of the nozzle body 34. The nozzle body 34 is attached to the nozzle holder 37 by a retainer 36. A nozzle needle 38 is slidably held in the nozzle body 34. The upper end of the nozzle needle 38 is pressed downward by the compression coil spring 40 in the nozzle holder 37 via the pressing rod 39. As a result, the nozzle needle 38 is pressure-bonded to the valve seat 41 formed on the nozzle body 34 to shut off the fuel. Further, the nozzle holder 37 is formed with a fuel passage 42 communicating with the injection pipe 24. The fuel passage 42 communicates with the fuel passage 43 of the nozzle body 34. A fuel sump 51 is formed at the end of the fuel passage 43.

The upper end of the spring 40 pressing the pressing rod 39 is received by the spring receiver 44. An adjusting screw 45 is attached to the upper end of the spring receiver 44. The adjusting screw 45 is screwed with a female screw 46 formed on the inner peripheral surface of the nozzle holder 37. Further, a pair of protrusions 48 is formed on the side surface side of the nozzle holder 37, male screws 49 are formed on these protrusions 48, and the injection pipe 24 is formed by a connecting nut 50 screwed with these male screws 49. Nozzle holder 37
It is designed to be connected to.

Next, the structure of each pump unit 26 of the fuel injection pump 25 will be described. As shown in FIG. 3, a tappet 55 is attached to the lower end of the plunger 54. The tappet 55 is pressed downward by the compression coil spring 56, and thereby pressed against the outer peripheral surface of the cam 30. A spill port 58 is formed in the barrel 57 in which the plunger 54 is slidably fitted, and an inclined groove 59 is formed in the outer peripheral surface of the plunger 54 so as to substantially face the spill port 58. ing.

A pinion 60 is rotatably supported on the outer peripheral side of the barrel 57. A control sleeve 61 is fixed to the pinion 60 and a notch 62 formed in the control sleeve 61.
Receives the engagement plate 63. The engagement plate 63 is fixed to the plunger 54.

A delivery valve 64 is provided on the outlet side of each pump unit 26, and is arranged on a valve seat 66 provided at the bottom of the casing 65.
The delivery valve 64 is pressed toward the valve seat 66 by the coil spring 67.

Next, an outline of the operation of the fuel injection device having the above structure will be described.

The timer 31 is controlled by a part of the output of the engine.
When the cam shaft 29 of the column fuel injection pump 25 is driven via the cam, the cam 30 pushes up the roller of the tappet 55, which causes the plunger 54 to move upward in the barrel 57. Then, the peripheral surface of the plunger 54 closes the spill port 58 and starts the pressure feeding of the fuel. When the plunger 54 moves further upward, the inclined groove 59 eventually aligns with the spill port 58, whereby the pressure in the space above the plunger 54 escapes to the spill port 58 side through the inclined groove 59, and the fuel is pumped. finish.

Mechanical governor 2 of fuel injection pump 25
When the 7 moves the control rack 28, the pinion 60 is rotated, which causes the control sleeve 6 to move.
1 will be rotated. The rotation of the control sleeve 61 is transmitted to the plunger 54 via the notch 62 and the engaging plate 63, and the plunger 54 is rotated in the barrel 57. Therefore spill port 5
8, the effective stroke determined by the position of the inclined groove 59 aligned with 8 is changed, the fuel is metered,
The supply amount of fuel injected at one time is controlled. The timer 31 provided on the camshaft 29 of the fuel injection pump 25 controls the phase angle of the camshaft 29 and adjusts the fuel injection timing.

When the plunger 54 pumps the fuel in the barrel 57, the delivery valve 64 is opened and the fuel is pumped to the fuel injection nozzle 20 through the injection pipe 24. The fuel passage 4 of the fuel injection nozzle 20 shown in FIG.
When fuel pressure is applied to the fuel sump 51 through 2 and 43, the nozzle needle 38 moves through the rod 39 into the spring 4
0 is compressed and moves upward, whereby the tip end side portion of the nozzle needle 38 separates from the valve seat 41, and fuel is injected through the injection port 35. When the pressure feed of the fuel is completed, the elastic restoring force of the spring 40 pushes the nozzle needle 38 downward via the rod 39, and the tip end thereof is pressed against the valve seat 41 to stop the fuel injection.

The fuel is sprayed by the injection port 3 of the fuel injection nozzle 20.
5, the fuel is injected toward the combustion chamber 21 formed on the top surface of the piston 12 shown in FIG. Then, this fuel spray is spontaneously ignited by the heat of the compressed intake air, combustion occurs in the cylinder 11, the piston 12 is pushed downward, and the output of the engine is taken out.
After this, the exhaust valve 19 is opened, and exhaust gas is discharged through the exhaust port 17.

The nozzle body 34 on the tip side of the fuel injection nozzle 20 of the fuel injection device for injecting fuel in this manner.
As shown in FIGS. 4 to 6, six injection positions are provided, and three injection ports 35 are formed at each injection position. That is, in the diameter of the conventional nozzle shown by the chain line in FIG. 5, three fine nozzles 35 each having a diameter of 10 to 150 μm are formed. As a result, the total area of the injection holes is reduced, the fuel pressure at the time of injection is increased, and a large number of fine injection holes 35 having the same diameter are provided to form a lean mixing region as shown in FIG. 7 by mixing due to turbulent flow. I am trying. Fine nozzle 3
The number of 5 may be two, or may be four or more.

According to the fuel injection nozzle 20 using the nozzle body 34 in which three fine injection holes 35 are formed at each injection position, the combustion chamber 2 of the piston 12 is
Fuel spray 70 as shown in FIGS.
Will be jetted. Here, with the fine injection port 35 having the same diameter as the core, for example, the fuel pressure is 800 to 3000 kg /
With the high-pressure injection of cm ² , it becomes possible to form a lean mixed region around the turbulent flow. As a result, the utilization rate of air is improved and the ignitability is improved.

That is, when the timing retard is performed to improve the exhaust gas, particularly to reduce the amount of nitrogen oxides, the ignition delay is rather increased, and the amount of nitrogen oxides is increased.
It causes a misfire problem. However, as described above, the nozzle body 3 having the fine injection ports 35 formed at the respective injection positions
By using No. 4, it is possible to improve the ignitability at the time of timing retardation and to form a lean mixed region as shown in FIG. 7 at an early stage. This makes it possible to improve the ignition delay and solve the misfire problem.

FIGS. 10 to 14 show the fuel injection nozzle 20 of the second embodiment, and at each injection position of the nozzle body 34, as shown in FIGS. To form. It should be noted that the diameters of these fine injection holes 35 are 10 to 150, as shown in FIG.
It is in the range of μm. The eight fine nozzles 35 are arranged in the area of the conventional nozzle shown by the chain line in FIG. The arrangement of the eight fine nozzles 35 is not necessarily limited to the arrangement shown in FIG. 12, and various arrangement forms such as a staggered arrangement are possible. Further, such a fine injection port 35 is formed by, for example, electric discharge machining.

As described above, eight fine injection holes 35 each having an extremely small size are provided at each injection position, and high-pressure injection is performed from these injection holes 35 with a fuel pressure of 800 to 3000 kg / cm ² . Here the nozzle body 3
As shown in FIG. 10, the inner portion of the injection port 35 of No. 4 has a concave portion 6
9, the nozzle 69 is formed by such a recess 69.
The length in the axial direction of is adjusted.

In this way, a large number of fine injection ports 35 are formed at each injection position, and the apparent injection length of the spray from each fine injection port 35 is lengthened, so that the fuel spray 70 is combined with the high pressure injection so that the fuel spray 70 shown in FIG. And as shown in FIG. 14, it becomes difficult to spread, and a large number of sprays 70 are jetted from the minute nozzles 35 as independent flows. Then, as shown in FIG. 13, when it collides with the wall surface of the combustion chamber 21, in particular, a spray that is widely dispersed and spread is formed.

Therefore, by forming such a spray 70, the ignition delay due to the timing retard is prevented and the occurrence of misfire is avoided. Therefore, even if the timing retardation for reducing the nitrogen oxides is performed, good combustion can be achieved.

Next, a third embodiment will be described with reference to FIGS. In this embodiment, the fuel injection nozzle 2
The main injection port 71 and the sub injection port 72 are formed at each injection position on the tip side of the nozzle body 34 of No. 0. FIG. 16 shows such an arrangement of the main injection holes 71 and the sub injection holes 72, and has a relatively large diameter at the center, for example, a diameter of 15
The main injection port 71 having a diameter of 0 to 400 μm is formed, and four auxiliary injection ports 72 having a diameter of 10 to 150 μm are formed around the main injection port 71. It should be noted that the circular chain line connecting the central portions of the sub injection ports 72 substantially corresponds to the diameter of the conventional injection port.

As described above, in the present embodiment, the total injection area of the nozzle body 34 is reduced, thereby increasing the fuel pressure at the time of injection to a pressure of 800 to 3000 kg / cm ² , and At a certain injection hole position, a plurality of minute injection holes 72 are provided on the outer side of the main injection position as shown in FIG. In this way, by forming the spray of the small injection port 72 around the main injection port 71 due to the high pressure and forming the lean mixed region to further improve the air utilization rate, it is possible to improve the ignitability. . That is, it is possible to prevent the ignition delay due to the timing retard for reducing the nitrogen oxides and eliminate the misfire.
19 and 20 show a state in which such spray is formed in the combustion chamber 21 of the piston 12.

Next, a fourth embodiment will be described with reference to FIGS. In this embodiment, a main nozzle 71 having a diameter smaller than that of the conventional one, for example, 150 to 400 μm, and a sub nozzle 72 having a smaller diameter, for example, 10 to 150 μm, located above the main nozzle 71 are provided. It is provided at the injection position. The upper and lower positional relationships between the main injection port 71 and the sub injection port 72 may be reversed. That is, the sub injection port 72 is formed in parallel with the main injection port 71 so as to form a pair with the main injection port 71.

As shown in FIGS. 24 and 25, the upper portion of the main injection port 71 is oriented so that the direction of the spray from the main injection port 71 is the same as the direction of the swirl 73 in the combustion chamber 21 of the piston 12. A small injection port 72 is provided in the. The spray atomized by the small nozzle 72 is the main nozzle 71
24 and 25, the turbulent flow is merged with the jet flow and the squish flow is collided with the jet flow to locally promote mixing and improve the ignitability.

Therefore, such a main jet 71 and a sub jet 72
Even when the fuel injection valves are provided at the respective injection positions, the ignition delay of the fuel due to the timing retard for improving the exhaust gas is improved, and misfire is eliminated.

Next, a fifth embodiment will be described with reference to FIGS. In this embodiment, as shown in FIGS. 26 and 27, with respect to the main injection ports 71 provided at the tip side of the nozzle body 34 at intervals of 60 ° in the circumferential direction, the diameter is 1 at the upper part.
The same number of minute auxiliary injection holes 72 of 0 to 150 μm are provided. Here, the axes of all the main nozzles 71 and the axes of all the sub nozzles 72 are the center points P in the nozzle body 34.
It is supposed to meet at. Also, 6 main nozzles 71 and 6
The sum of the cross-sectional areas of the individual injection holes 72 is set to be equal to or less than the sum of the cross-sectional areas of the conventional injection holes.

As shown in FIGS. 28 and 29, the fuel spray 70 injected from the six main nozzles 71 and the six auxiliary nozzles 72 on the upper side of the piston 12 reaches the top dead center of the piston 12. In the combustion chamber 21, the intake air is merged with the squash flow of the intake air, whereby a mixing region is locally formed, and the ignitability is improved.

30 and 31 respectively show the combustion temperature and the heat generation amount when the fuel is injected by such a nozzle body 34. The auxiliary injection ports 72 provided on the respective main injection ports 71 promote atomization of the fuel and achieve lean combustion, so that ignition delay is suppressed and diffusion combustion is promoted. Therefore, changes in the combustion temperature and the heat generation rate become slower than in the conventional case, and the combustion period can be advanced as compared with the conventional case. Then, it becomes possible to prevent the increase of nitrogen oxides due to the increase of the combustion temperature due to the ignition delay.

Next, a sixth embodiment will be described with reference to FIGS. In this embodiment, as shown in FIGS. 32 to 34, a main injection port 71 is provided at each injection position, and a sub injection port corresponding to the main injection port 71 on the lower side thereof is composed of a minute injection port having a diameter of 10 to 150 μm, for example. 72 is formed. That is, the nozzle body 34 of the present embodiment is characterized in that the total area of the nozzles is reduced to a high pressure by reducing the total area, and the large and small nozzles are provided at positions where they do not interfere with each other in the swirl flow. There is. Also in this embodiment, the axes of the six main injection ports 71 and the six auxiliary injection ports 72 intersect with each other at a point P inside the nozzle body 34.

As described above, since the large and small injection holes 71 and 72 of the large and small sizes are formed at the positions where they do not interfere with each other in the flow direction of the swirl, as shown in FIGS. The main injection port 71 in the flow direction
And the sub-injection port 72 on the lower side thereof injects fuel spray, thereby improving the utilization rate of air in the combustion chamber 21 of the piston 12. The main spout 71
Combustion can be improved because the fuel spray injected from the nozzle and the fuel spray injected from the auxiliary nozzle 72 are turbulently mixed with each other.

Next, a seventh embodiment will be described with reference to FIGS. In this embodiment, the main injection port 71 of the nozzle body 34
In order to further improve the spread of the fuel spray from the main injection port 71, a small injection port 72 having a diameter of 150 μm or less is branched from the main injection port 71 in the middle of the main injection port 71 along the flow direction of the intake swirl. It is formed to promote mixing of fuel and air. That is, the conventional main injection port 71
In addition, the auxiliary injection port 72 for injecting a small amount of fuel in the swirl direction of the intake air is branched and provided.

When such a nozzle is used, as shown in FIGS. 40 and 41, the fuel spray from the main injection port 71 is slightly sprayed with the fuel spray from the auxiliary injection port 72 in the swirl flow direction. The fuel is sprayed at different angles, the fuel spray spreads in the circumferential direction of the piston 12, and the mixing of the fuel with the air in the combustion chamber 21 of the piston 12 is promoted.

Next, an eighth embodiment will be described with reference to FIGS. In this embodiment, as shown in FIGS. 42 to 44, the main injection port 7 is provided to improve the spread of the spray, with respect to the main injection port 72 provided at each injection position of the nozzle body 34.
1 above and below the main injection port 71 and the diameter is 15
A sub-injection port 72 having a diameter of 0 μm or less is provided to promote mixing of fuel and air. That is, it has a structure in which a plurality of minute auxiliary injection holes 72 are provided above and below the conventional main injection hole 71.

The fuel spray 70 from the main injection port 71 and the sub injection port 72 of the nozzle body 34 is as shown in FIGS. 45 and 46. In particular, as shown in FIG. 46, in the combustion chamber 21 of the piston 12, since the spray from the main injection port 71 is injected above and below the spray from the auxiliary injection port 72 respectively, the spray of fuel from each injection position goes up and down. As a result, the utilization rate of air in the combustion chamber 21 is further improved.

Next, a ninth embodiment will be described with reference to FIGS. 47 to 51. In this embodiment, a main injection port 71 is formed at each injection position in the tip side portion of the nozzle body 34, and two main auxiliary injection ports 72 are provided at the top and bottom so as to branch from the middle of each main injection port 71. It is designed to be formed. Therefore, at each injection position, the main injection port 71 is formed at an intermediate position in the height direction, and two sub injection ports 72 are formed above and below the main injection port 71. The main nozzle 71 has a diameter of 150 to 400 μm, and the auxiliary nozzle 72 has a diameter of 10 to 150 μm.

In this way, by arranging four auxiliary injection ports 72 above and below the main injection port 71 at each injection position, the fuel spray as shown in FIGS. 50 and 51 is injected into the combustion chamber 21 of the piston 12. Is jetted. In particular, as shown in FIG. 51, since the fuel spray spreads vertically at each injection position, the utilization rate of air in the combustion chamber 21 of the piston 12 is improved, which leads to improvement of combustion, resulting in more stable operation. You will be able to achieve combustion.

The number of sub injection holes 72 formed above and below the main injection hole 71 is not necessarily two as in the above-described embodiment, but three or more in each case. Alternatively, the auxiliary injection port may be formed by branching. Alternatively, the auxiliary injection port 7 formed by branching up and down
You may make it the number of 2 change up and down mutually.

Next, a tenth embodiment will be described with reference to FIGS. In this embodiment, a plurality of fine injection holes 75 are formed at each injection position of the nozzle body 34. As shown in FIG. 52 to FIG. 55, at the tip end portion of the nozzle body 34 and at the injection positions provided at intervals of 60 ° in the circumferential direction, five fine injection ports 75 are formed at each position. ing. These fine nozzles 75 are 10
It has a diameter of 150 μm, and has a structure in which four fine jet ports 75 are arranged on the upper, lower, left and right sides of the fine jet port 75 at the center. It is more preferable that these five fine injection holes 75 have side portions communicating with each other as shown in FIG. 55.

When the nozzles are formed by such an assembly of the minute nozzles 75, as shown in FIG. 56, the fuel spray from each injection position spreads and the combustion chamber 2 of the piston 12 expands.
The utilization rate of the air in 1 is improved, and the mixing is promoted. That is, the combustion chamber 21 associated with the improvement of the spray spread
By promoting the mixing with the air in the inside, combustion is improved, more stable combustion can be achieved, and deterioration of combustion due to timing retard can be prevented.

Next, an eleventh embodiment is shown in FIGS. 57 and 58.
Explained by. Emission improvement of diesel engine,
Particularly, in order to reduce hydrocarbons and particulate matter, when a zero suck nozzle in which the suck volume of the nozzle body 34 is set to almost zero is used, the flow rate coefficient of fuel at the tip of the nozzle body 34 becomes small, and the spray is discharged. Is deteriorated, mixing with air in the combustion chamber is poor, and combustion is deteriorated. Therefore, in this embodiment, in order to eliminate the above-mentioned drawbacks, a plurality of types of fine injection holes 75 having different diameters are arranged vertically at each injection position of the nozzle body 34 of the zero sack nozzle so that the fuel spray can be sprayed in the air. It is designed to give a spread to.

In the zero suck nozzle in which the suck portion of the fuel pool formed at the tip of the nozzle body 34 is set to zero in order to reduce the hydrocarbons in the exhaust gas, the fuel flow is as described above. As compared with the nozzle having the above, the spread of the fuel spray and the reaching distance are small, the mixing with the air is poor, and the combustion is deteriorated.

Therefore, as shown in FIG. 57, at each injection position, a fine injection port 75 having a diameter of 300 μm is provided on the lower side, a fine injection port 75 having a diameter of 200 μm is provided in the middle, and a diameter of 10 is provided on the upper side.
The fine injection holes 75 of 0 μm are respectively formed. In this way, the large, medium and small fine injection holes 75 are formed at each injection position. The reason why the diameter of the fine injection port 75 is made smaller toward the upper side is that the spray of fuel is prevented from adhering to the lower surface of the cylinder head 15 and the air utilization rate near the lower surface of the cylinder head is improved. This is because

In this way, large, medium, and small fine injection holes 7 are provided at each injection position.
FIG. 58 shows the fuel sprayed by the nozzle body 34 composed of the zero suck nozzle provided with No. 5, and the spread of the fuel spray in the combustion chamber 21 of the piston 12 into the air is sufficiently given. Become. Therefore, with such a configuration, the utilization rate of air in the combustion chamber 21 is further improved, and it is possible to achieve both reduction of hydrocarbons by the zero suck nozzle and improvement of combustion.

Although the first to eleventh embodiments are all directed to the fuel injection device including the combination of the fuel injection pump 25 and the fuel injection nozzle 20, the present invention is directed to the fuel injection nozzle and the fuel injection pump. The present invention can also be applied to an overhead cam drive type unit injector in which (1) and (2) are integrated, and in this case, a plurality of fine injection ports may be formed at each injection position of the nozzle body on the tip side thereof. Further, it is also applicable to a pressure accumulation type fuel injection device in which fuel pressure pressurized by a pump is accumulated by an accumulator and fuel pressure is intermittently applied to a fuel injection nozzle by a timing adjustment valve. Also in this case, a plurality of injection holes are formed at each injection position on the tip side of the fuel injection nozzle.

[0052]

As described above, according to the present invention, a plurality of fine injection holes are formed at each injection position.
Therefore, it becomes possible to form a lean mixed region by mixing of the sprays from the plurality of fine injection holes due to the turbulent flow, and the ignitability is improved. Therefore, even if the timing retardation for improving the exhaust gas is performed, the ignition delay does not increase, or the misfire associated therewith is prevented.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a diesel engine including a fuel injection device according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a fuel injection nozzle.

FIG. 3 is a perspective view of a main part of a fuel injection pump.

FIG. 4 is an enlarged cross-sectional view of the tip of the nozzle body.

FIG. 5 is a front view showing the arrangement of nozzles.

FIG. 6 is a bottom view of the tip of the nozzle body.

FIG. 7 is an enlarged cross-sectional view showing formation of a lean mixed region by spraying fuel.

FIG. 8 is a cross-sectional view showing a state of atomization of the piston in the combustion chamber.

FIG. 9 is a vertical sectional view of the same.

FIG. 10 is an enlarged cross-sectional view of the nozzle body at the tip of the fuel injection nozzle of the second embodiment.

FIG. 11 is a bottom view of the tip of the nozzle body.

FIG. 12 is a front view showing the arrangement of nozzles.

FIG. 13 is a cross-sectional view of the piston showing a state of fuel spray.

FIG. 14 is a vertical sectional view of the same.

FIG. 15 is an enlarged cross-sectional view of the nozzle body of the fuel injection nozzle of the third embodiment.

FIG. 16 is an enlarged front view showing the arrangement of nozzles.

FIG. 17 is a bottom view of the tip of the nozzle body.

FIG. 18 is a cross-sectional view of essential parts showing the formation of a lean mixture region.

FIG. 19 is a cross-sectional view of the piston showing a state of fuel spray.

FIG. 20 is a vertical sectional view of the same.

FIG. 21 is an enlarged vertical cross-sectional view of the tip of the nozzle body of the fuel injection nozzle of the fourth embodiment.

FIG. 22 is a bottom view of the tip of the nozzle body.

FIG. 23 is a front view showing the arrangement of nozzles.

FIG. 24 is a transverse cross-sectional view of the piston showing a state of expansion of fuel spray.

FIG. 25 is a vertical sectional view of the piston.

FIG. 26 is an enlarged cross-sectional view of the tip of the nozzle body of the fifth embodiment.

FIG. 27 is a bottom view of the tip of the nozzle body.

FIG. 28 is a cross-sectional view showing a state of atomization of the piston in the combustion chamber.

FIG. 29 is a vertical sectional view of the same.

FIG. 30 is a graph showing changes in combustion temperature.

FIG. 31 is a graph showing changes in heat generation rate.

FIG. 32 is an enlarged cross-sectional view of the tip of the nozzle body of the sixth embodiment.

FIG. 33 is a bottom view of the tip portion of the nozzle body.

FIG. 34 is a front view showing the arrangement of nozzles.

FIG. 35 is a cross-sectional view showing a state of atomization of the piston in the combustion chamber.

FIG. 36 is a vertical sectional view of the same.

FIG. 37 is an enlarged cross-sectional view of the tip of the nozzle body of the seventh embodiment.

FIG. 38 is a bottom view of the tip portion of the nozzle body.

FIG. 39 is a front view showing the arrangement of nozzles.

FIG. 40 is a transverse sectional view showing a state of fuel spray in the combustion chamber of the piston.

FIG. 41 is a vertical sectional view of the same.

FIG. 42 is an enlarged cross-sectional view of the tip of the nozzle body of the eighth embodiment.

FIG. 43 is a bottom view of the tip of the nozzle body.

FIG. 44 is a front view showing the arrangement of nozzles.

FIG. 45 is a transverse cross-sectional view showing a state of fuel spray in the combustion chamber of the piston.

FIG. 46 is a vertical sectional view of the same.

FIG. 47 is an enlarged cross-sectional view of the tip of the nozzle body of the ninth embodiment.

FIG. 48 is a bottom view of the tip of the nozzle body.

FIG. 49 is a front view showing the arrangement of nozzles.

FIG. 50 is a transverse cross-sectional view showing a state of fuel spray in the combustion chamber of the piston.

FIG. 51 is a vertical sectional view of the same.

FIG. 52 is an enlarged cross-sectional view of the tip of the nozzle body of the tenth embodiment.

FIG. 53 is a bottom view of the tip of the nozzle body.

FIG. 54 is an enlarged vertical cross-sectional view of a nozzle portion.

FIG. 55 is a front view showing the arrangement of nozzles.

FIG. 56 is a vertical cross-sectional view showing the state of atomization of the piston in the combustion chamber.

FIG. 57 is an enlarged cross-sectional view of the tip of the nozzle body of the eleventh embodiment.

FIG. 58 is a vertical cross-sectional view showing a state of atomization of the piston in the combustion chamber.

[Explanation of symbols]

 10 Cylinder Block 11 Cylinder 12 Piston 13 Piston Pin 14 Connecting Rod 15 Cylinder Head 16 Intake Port 17 Exhaust Port 18 Intake Valve 19 Exhaust Valve 20 Fuel Injection Nozzle 21 Combustion Chamber 24 Injection Pipe 25 Fuel Injection Pump 26 Pump Unit 27 Mechanical Governor 28 Control Rack 29 Cam Shaft 30 Cam 31 Timer 34 Nozzle Main Body 35 Nozzle 36 Retainer 37 Nozzle Holder 38 Nozzle Needle 39 Push Rod 40 Spring 41 Valve Seat 42, 43 Fuel Passage 44 Spring Bearing 45 Adjusting Screw 46 Female Thread 47 Cap 48 Projection 49 Male Thread 50 Connection Nut 51 Fuel sump 52 One-way valve 54 Plunger 55 Tappet 56 Coil spring 57 Barrel 58 Spill port 59 Sloping groove 60 Anions 61 the control sleeve 62 the notch 63 engagement plate 64 Deriberibarubu 65 casing 66 valve seat 67 coil spring 69 recess 70 fuel spray 71 main injection hole 72 sub-injection ports 73 swirl 75 fine spray port

Claims (1)

[Claims] 1. A fuel injection device for injecting pressurized fuel in an atomized form, wherein a plurality of fine injection holes are formed at each injection position.