JP2556333Y2 - Fuel injection nozzle - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fuel injection nozzle used for a diesel engine or the like.

[0002]

2. Description of the Related Art Conventional fuel injection nozzles include a conventional fuel injection nozzle.
There is a type disclosed in US Pat. This fuel injection nozzle includes a nozzle body 1 and a valve body 2 as shown in FIG. Inside the nozzle body 1,
A valve sliding hole 11 extending in the vertical direction is formed. At the lower end opening of the valve sliding hole 11, a tapered hole-shaped valve seat 12 whose diameter increases as it goes downward is formed.

The valve body 2 has a shaft portion 21 slidably inserted into the valve slide hole 11 and a valve portion 22 connected to a lower end portion of the shaft portion 21 protruding from the valve slide hole 11. It is composed of A fuel passage 21a extending on the axis of the shaft portion 21 is formed inside the shaft portion 21. An injection hole 21b having one end opening on the inner peripheral surface of the fuel passage 21a and the other end opening on the outer peripheral surface of the shaft portion 21 is formed. Are formed. On the other hand, the valve portion 22 is formed to have the same diameter as the lower end portion of the valve seat 12 or a diameter slightly smaller than the lower end portion.
A slightly larger tapered portion 22a is formed. The outer peripheral edge of the tapered portion 22a is abutted against the valve seat 12 by a nozzle spring (not shown) so that the valve portion 22 is seated on the valve seat 12. When the valve portion 22 is seated on the valve seat 12, the injection hole 21b faces the inner peripheral surface of the valve sliding hole 11.

In the fuel injection nozzle having the above-described structure, when fuel is fed from a fuel injection pump (not shown) and the pressure of the fuel reaches a predetermined valve opening pressure, the valve body 2 resists the urging force of the nozzle spring. And lifts (moves downward) from the valve seat 12. Then, the pressure-fed fuel passes through the fuel passage 21a and is injected from the injection hole 21b. The injected fuel is
The fuel is injected between the valve seat 12 and the tapered portion 22a into the combustion chamber of the engine.

[0005] The injection form of the fuel injected into the combustion chamber changes as follows according to the load of the engine. That is,
When the engine load is low and the load is low, the pressure of the fuel is low, so the penetration of the injected fuel (penetration force)
And the fuel is injected into the space near the fuel injection nozzle. On the other hand, when the engine load is high and the load is high, the fuel pressure is high and the fuel injection amount is large, so that the penetration is correspondingly increased. Therefore, the fuel reaches a location far away from the fuel injection nozzle. Thereby, at the time of high load, the air in the combustion chamber is used efficiently.

[0006]

However, the conventional fuel injection nozzle described above has not been able to sufficiently satisfy the air utilization rate under a high load. That is, the spread of the fuel due to the strength of the penetration is, so to speak, linear, and there is no spatial spread. For this reason, it has not been possible to improve the utilization rate of air under a high load to a satisfactory degree. Therefore, conventionally, it has been desired to improve the air utilization rate by spatially expanding the injected fuel. However, at low and medium load,
In particular, when the load is low, if the injected fuel is excessively widened, the density of the fuel becomes lean and causes a misfire. Therefore, when the load is low, it is necessary to prevent the injected fuel from spreading excessively.

The present invention has been made in consideration of the above circumstances, and does not allow the injected fuel to spread excessively at low and medium loads, and increases the spread of fuel at high loads, thereby utilizing the air. It is an object of the present invention to provide a fuel injection nozzle capable of greatly improving the efficiency.

[0008]

According to the present invention, in order to achieve the above-mentioned object, a valve slide hole having one end opened to the outside is formed inside the valve slide hole, and the valve slide hole faces outwardly at the opening of the valve slide hole. A nozzle body formed with a tapered hole-shaped valve seat that expands in diameter,
A valve body slidably provided in the valve sliding hole, and a valve body having a valve portion seated on the valve seat formed at an end protruding outside from the valve sliding hole; Has a fuel passage extending in the axial direction thereof, and one end is opened on the inner peripheral surface of the fuel passage. When the valve portion is seated on the valve seat, the valve slides in the vicinity of the valve seat. An injection hole having the other end opened is formed on the outer peripheral surface of the valve body facing the inner peripheral surface of the hole, and when the valve portion is lifted from the valve seat, the fuel injected from the injection hole is supplied to the valve. In a fuel injection nozzle configured to inject outside from between a seat and the valve portion, a second injection hole is formed in the valve body, and one end of the second injection hole is connected to an inner peripheral surface of the fuel passage. The opening of the injection hole is opened at a position spaced apart in the axial direction of the valve body with respect to the opening of the injection hole, the other end of the second injection hole Body is characterized in that in the outer peripheral surface was opened at substantially the same place as the opening of the injection hole of the.

[0009]

The opening of the fuel passage and the opening of the second injection hole are separated from each other in the axial direction of the valve body, and the openings on the outer peripheral surface of the valve body are opened at substantially the same location. That is, the injection hole and the second injection hole intersect on the outer peripheral surface of the valve body. When they intersect in this manner, the fuel injected from the injection hole and the second injection hole tends to spread in the axial direction of the valve body by interfering with each other. In this case, when the load is low or medium, the lift amount of the valve body is small, and the distance between the valve seat and the valve portion of the valve body is small.
Excessive spread is prevented by the valve seat and valve body. On the other hand, when the load is high, the lift amount of the valve body is large and the distance between the valve seat and the valve portion is wide, so that the injected fuel spreads largely in the axial direction of the valve body.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, the overall configuration of the fuel injection nozzle N according to the present invention will be described with reference to FIG. 4. The fuel injection nozzle N includes a nozzle body 3. The nozzle body 3 includes a nozzle holder 31 and a nozzle body 33 fixed to a lower end surface of the nozzle holder 31 by a nozzle nut 32. Note that the nozzle holder 31 and the nozzle body 33 are positioned by the positioning pins 4.

A fuel hole 31a extending downward from the upper end surface of the nozzle holder 31 is formed inside the nozzle holder 31. The fuel hole 31a is formed continuously with the lower end of the fuel hole 31a. Extended spring storage hole 3
1b is formed. The spring housing hole 31b houses a nozzle spring 5 for urging a valve body 6 described later upward in FIG. In addition, in the spring storage hole 31b,
High-pressure fuel is pressure-fed from a fuel injection pump (not shown) through a fuel hole 31a.

The nozzle body 33 is formed with a valve slide hole 33a penetrating the axis from the upper end surface to the lower end surface. The lower end opening of the valve slide hole 33a has a tapered valve seat 3 whose diameter gradually increases downward.
3b (see FIG. 1) is formed. Further, a tapered surface 33c whose diameter gradually decreases downward is formed on the outer peripheral surface of the lower end portion of the nozzle body 33.

In the valve sliding hole 33a of the nozzle body 33,
The valve 6 is slidably inserted. The valve element 6 has a shaft portion 61 inserted through the valve sliding hole 33a and a valve portion 6 connected to a lower end portion of the shaft portion 61 protruding from the valve sliding hole 33a.
And 2.

The upper end of the shaft portion 61 has a valve slide hole 3.
The spring receiving hole 31b penetrates through the hole 3a and protrudes into the spring receiving hole 31b, in which the spring receiver 7 is fixed. The shaft portion 61 is urged upward by the nozzle spring 5 via the spring receiver 7. Thus, the valve portion 62 is seated on the valve seat 33b. On the other hand, the shaft 6
1 is pressed downward by the fuel pumped into the spring housing hole 31b. When the pressing force is larger than the urging force of the nozzle spring 5, the valve 6 is lifted (moved downward). The pressure of the fuel when the valve 6 starts to lift is the valve opening pressure.

On the other hand, as shown in FIG. 1, the valve portion 62 is formed on its outer peripheral surface with a tapered surface 62a continuous with the tapered surface 33c of the nozzle body 33. Also, the valve section 6
A tapered portion 62b is formed on the upper end surface of the second member 2. The taper angle of the tapered portion 62b is larger than the taper angle of the valve seat 33b. Therefore, the valve portion 62
The outer peripheral edge of the tapered portion 62b abuts on the outer peripheral edge of the valve seat 33b so as to be seated on the valve seat 33b.

The shaft portion 61 is formed with a fuel passage 63 extending downward from the upper end surface on the axis. Four injection holes 64 are formed in the shaft 61 near the lower end of the fuel passage 63. Each injection hole 64
Are arranged at the same position in the axial direction of the shaft portion 61, at equal intervals in the circumferential direction of the shaft portion 61, and are arranged point-symmetrically with respect to the axis of the shaft portion 61.
One end of each injection hole 64 opens on the inner peripheral surface of the fuel passage 63 (hereinafter, referred to as an inner opening 64a), and the other end opens on the outer peripheral surface of the shaft portion 61 (hereinafter, referred to as an outer opening 64b). doing.

The outer opening 64b of the injection hole 64 is located below the inner opening 64a, and the injection hole 64 faces obliquely downward. In particular, in this embodiment, the angle between the injection hole 64 and the axis of the valve body 6 is smaller than the angle between the valve seat 33b and the axis of the valve body 6 (half the taper angle of the valve seat 33b). And the angle between the tapered portion 62b and the axis of the valve body 6 (half the taper angle of the tapered portion 62b).
Has been made larger. The angle between the injection hole 64 and the axis of the valve body 6 may be equal to the angle between the valve seat 33b and the axis of the valve body 6, or may be equal to the angle between the tapered portion 62b and the valve body 6.
May be set to be equal to the angle formed by the axis. When the valve portion 62 is seated on the valve seat 33b, the outer opening 64b of the injection hole 64 is disposed so as to be located slightly above the valve seat 33b. Are facing each other. Needless to say, as in the above-described conventional example, it may be arranged so as to be in contact with the valve seat 33b.

The above configuration is the same as that of the conventional fuel injection nozzle.
A second injection hole 65 is formed in the shaft portion 61 of this embodiment, and this point differs from the conventional fuel injection nozzle. The second injection hole 65 is for expanding the fuel injected from the fuel injection nozzle N at the time of high load in the axial direction of the valve body 6 and has the following configuration.

That is, the second injection hole 65 is
One end of each second injection hole 65 is opened on the inner peripheral surface of the fuel passage 33a (hereinafter, referred to as an inner opening 65a), and the other end is a lower end of the shaft 61. An opening (hereinafter, referred to as an outer opening 65b) is provided on the outer peripheral surface.

The four second injection holes 65 are paired with the injection holes 64, respectively. Each of the injection holes 65 is arranged at the same position in the circumferential direction of the valve body 6 with respect to the injection hole 65 forming a pair. However, with respect to the axial direction of the valve element 6, the inner opening 65 a is the inner opening 64 a of the injection hole 64.
Are arranged on the upper side. On the other hand, the outer opening 65
b is disposed at the same position as the outer opening 64 b of the injection hole 64. That is, the angle between the second injection hole 65 and the axis of the valve body 6 is smaller than the angle between the injection hole 64 and the axis of the valve body 6, and the second injection hole 65 intersects with the injection hole 64 on the outer peripheral surface of the shaft portion 61. ing.

In this embodiment, the diameter of the second injection hole 65 is smaller than the diameter of the injection hole 64. Moreover, based on the relationship that the angle formed between the second injection hole 65 and the axis of the shaft portion 61 is smaller than the angle formed between the injection hole 64 and the axis of the shaft portion 61, as shown in FIG. The upper and lower edges of 65b are in contact with the upper and lower edges of the outer opening 64b of the injection hole 64. As a result, the outer opening 65b is included inside the outer opening 64b. Of course, the diameter of the second injection hole 65 is
4, the outer opening 65b of the second injection hole 65 has right and left edges contacting the outer opening 64b of the injection hole 64, as shown in FIG. The outer opening 64b is included inside.

As long as the second injection hole 65 crosses the injection hole 64 on the outer peripheral surface of the shaft portion 61, the axis of the second injection hole 65 is not necessarily the same as that of the injection hole 64 on the outer peripheral surface of the shaft portion 61. There is no need to cross the axis,
The axis of the injection hole 64 may be crossed slightly outside or inside the outer peripheral surface of the shaft portion 61. Also,
The axis of the second injection hole 65 may be slightly separated from the axis of the injection hole 64 in the circumferential direction on the outer peripheral surface of the shaft portion 61.

The operation of the fuel injection nozzle N having the above configuration will be described. When the fuel is pumped from the fuel injection pump to the fuel injection nozzle N, and the pressure becomes equal to or higher than the valve opening pressure, the valve 6
Lifts from the valve seat 33b. As shown in FIG. 5, in the lift state until the lower edges of the outer openings 64b, 65b of the injection holes 64, 65 come into contact with the inner periphery of the valve seat 33b, the fuel injected from the injection holes 64b, 65b. Is injected through a small gap between the valve slide hole 33a and the shaft portion 61 and between the valve seat 33b and the tapered portion 62b. In this case, since the interval between the valve seat 33b and the tapered portion 62b is narrow, the fuel injected from between them spreads in a thin film form as shown in FIG. However, the penetration at this time is very small, so that the fuel reach is short. The above-mentioned injection mode is injection at the time of low load such as at the time of idling.

At the time of medium load, as shown in FIG.
Part or all of the lower side of the outer openings 64b, 65b of the injection holes 64, 65 is exposed from the valve slide hole 33a, and the injection holes 6
Fuel is injected from 4,65. The fuel injected from the two injection holes 64 and 65 tends to spread in the axial direction of the valve body 6 by interfering with each other. However, at this time, since the interval between the valve seat 33b and the tapered portion 62b is narrow,
They regulate the spread of fuel. Therefore, the fuel does not spread significantly. Since the penetration is larger than that at the time of low load, the fuel reach distance becomes longer, and the injection mode shown in FIG. 8 is obtained.

At the time of high load, as shown in FIG.
The valve 6 lifts greatly. As a result, the injection holes 64, 6
5, the entirety of the outer opening portions 64b and 65b is the valve sliding hole 33a.
Of course, the valve seat 33b relatively moves to the upper side from the upper end edges of the outer openings 64b and 65b, so that the distance between the valve seat 33b and the tapered portion 62b increases. Therefore, at this time, the fuel injected from the injection holes 64 and 65 largely spreads in the axial direction of the valve body 6 without being restricted by the valve seat 33b and the tapered portion 62b. Needless to say, as shown in FIG. 10, the fuel reach becomes longer. Therefore, the fuel is injected toward a wide space, and the air in the combustion chamber is efficiently used.

It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention. For example, in the above embodiment, four injection holes 64 and second injection holes 65 are formed, but the number of formed injection holes can be changed as appropriate. Although the second injection hole 65 is arranged above the injection hole 64, it may be arranged below the injection hole 64.

[0027]

As described above, according to the fuel injection nozzle of the present invention, the second injection hole is formed in the valve body, and one end of the second injection hole is formed on the inner peripheral surface of the fuel passage. The valve is opened at a position spaced apart from the opening in the axial direction of the valve body, and the second
Since the other end of the injection hole is opened almost at the same location as the opening of the injection hole on the outer peripheral surface of the valve body, at low load, the injected fuel is prevented from spreading excessively and causing misfiring etc. Of course, when the load is high, not only the reach of the injected fuel becomes longer, but also the fuel spreads in the axial direction of the valve element. Therefore, it is possible to improve the utilization rate of the air in the combustion chamber, thereby achieving better combustion, and preventing black smoke and the like from being generated.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a main part of an embodiment of the present invention.

FIG. 2 shows outer openings 64b and 65b of injection holes 64 and 65.
FIG. 7 is a view of the injection hole 64 viewed from the outside in the axial direction of the injection hole 64.

FIG. 3 is a view similar to FIG. 2, showing another example of injection holes 64 and 65;

FIG. 4 is a cross-sectional view showing an entire configuration of an embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a lift state of the valve body when the load is low according to the embodiment of the present invention.

6 is a view of the fuel injection mode in the state shown in FIG. 5 as viewed from below the valve element 6 in the axial direction.

FIG. 7 is a sectional view similar to FIG. 5 at the time of medium load.

FIG. 8 is a view similar to FIG. 6, showing a fuel injection mode in the state shown in FIG. 7;

FIG. 9 is a sectional view similar to FIG. 5 at the time of high load.

FIG. 10 is a view similar to FIG. 6, showing a fuel injection mode in the state shown in FIG. 9;

FIG. 11 is a cross-sectional view showing a main part of an example of a conventional fuel injection nozzle.

[Explanation of symbols]

 3 Nozzle Body 33 Nozzle Body 33a Valve Sliding Hole 33b Valve Seat 6 Valve Body 61 Shaft Part 62 Valve Part 63 Fuel Passage 64 Injection Hole 64a Inner Opening 64b Outer Opening 65 Second Injecting Hole 65a Inner Opening 65b Outer Opening

Claims (1)

(57) [Scope of request for utility model registration] 1. A nozzle body in which a valve slide hole having one end opened to the outer surface is formed, and a tapered hole-shaped valve seat whose diameter increases outward is formed in the opening of the valve slide hole. A valve body slidably provided in the valve slide hole, the valve body having a valve portion seated on the valve seat at an end protruding to the outside from the valve slide hole. Inside, a fuel passage extending in the axial direction is formed, and one end is opened on the inner peripheral surface of the fuel passage, and the valve slide near the valve seat when the valve portion is seated on the valve seat. An injection hole having the other end opened is formed on the outer peripheral surface of the valve body opposed to the inner peripheral surface of the moving hole, and when the valve portion is lifted from the valve seat, the fuel injected from the injection hole is used for discharging the fuel. In a fuel injection nozzle configured to inject outside from between a valve seat and the valve portion, a second An injection hole is formed, and one end of the second injection hole is opened at an inner circumferential surface of the fuel passage at a position spaced apart from the opening of the injection hole in the axial direction of the valve body.
A fuel injection nozzle characterized in that the other end of the injection hole is opened on the outer peripheral surface of the valve body at substantially the same location as the opening of the injection hole.