JP2572443Y2 - Fuel injection nozzle - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection nozzle used for a diesel engine or the like, and particularly to a poppet type fuel injection nozzle.

[0002]

2. Description of the Related Art A conventional fuel injection nozzle of this type is shown in FIG.
As shown in FIG. 2, a nozzle body 1 and a valve body 2 are provided. The nozzle body 1 has a valve sliding hole 1a formed therein, and a valve seat 1b formed in an opening of the valve sliding hole 1a. ing. On the other hand, the valve body 2 is formed at a shaft portion 2a slidably inserted into the valve sliding hole 1a and at a lower end portion protruding from the valve sliding hole 1a, and is biased by a nozzle spring (not shown). A valve portion 2a is seated on a valve seat 1b, and a fuel passage 2c through which fuel is fed from a fuel injection pump (not shown) to the shaft portion 2a, and a fuel passage 2c extending from the fuel passage 2c to the outer peripheral surface. Extending injection holes 2d and 2e are formed.
The injection holes 2d and 2e are arranged apart from each other in the axial direction of the valve body 2. (See Japanese Utility Model Application Laid-Open No. 57-8363)

In the fuel injection nozzle having the above-described structure, when the pressure of the fuel pumped from the fuel injection pump exceeds the valve opening pressure determined by the nozzle spring, the valve body 2 opens the valve against the urging force of the nozzle spring. Lift downward from the seat 1b. Then, as shown in FIG. 13, the lower injection hole 2d is first exposed to the outside through the valve slide hole 1a, and fuel is injected from the injection hole 2d. When the valve body 2 is further lifted, the upper injection hole 2e is also exposed to the outside as shown in FIG.
Fuel is injected from both d and 2e. When the pumping of the fuel from the fuel injection pump is completed, the valve body 2 is seated on the valve seat by the nozzle spring, thereby ending the fuel injection.

FIG. 11 shows the fuel injection characteristics of the fuel injection nozzle. The fuel injection amount changes in two stages before and after the injection hole 2e is exposed to the outside from the valve slide hole 1a. I have.

The inventor of the present application has recently found that a good combustion state can be obtained by intermittently performing fuel injection by the fuel injection nozzle according to the lift of the valve body (see FIG. 9). Was. That is, when the fuel is intermittently injected according to the lift of the valve body, the pressure of the fuel at the time of the subsequent injection is greater than the pressure of the fuel at the time of the previous injection. Penetration). As a result,
A passing phenomenon occurs in which fuel injected later overtakes fuel injected earlier. In addition, since the particle diameter of the fuel to be injected later becomes smaller due to the pressure, the fuel having the large and small particle diameters can be appropriately dispersed in combination with the overtaking phenomenon. The reduction of HC and the reduction of combustion noise can be achieved, and the smoke and NOx can be reduced and the fuel efficiency can be improved at full load (Automobile Engineering Society of Japan, 1991 Autumn Science Lecture Presentation No. 243, 244). reference).

[0006]

However, in the above-described conventional fuel injection nozzle, as shown in FIG. 11, although the fuel injection amount can be changed in two stages, the fuel injection is performed continuously. However, fuel could not be injected intermittently.

The present invention has been made in consideration of the above circumstances, and provides a poppet type fuel injection nozzle capable of intermittently injecting fuel according to a lift of a valve body. Aim.

[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 in the inside, and the valve slide hole is formed in the outside where the valve slide hole opens. A nozzle body formed with a valve seat surrounding the opening of the sliding hole, slidably provided in the valve sliding hole, a fuel passage formed therein, and protruding outside from the valve sliding hole. A valve body formed with a valve part to be seated on the valve seat at an end of the nozzle body, and inside the nozzle body, one end is opened on the inner peripheral surface of the valve sliding hole, and the other end is provided. An injection hole that opens in the valve seat is formed, and a plurality of fuel reservoirs communicating with the fuel passage are formed on an outer peripheral surface of the valve body, and the plurality of fuel reservoirs are formed by moving the valve body from the valve seat. As the valve lifts, it is separated from each other in the axial direction of the valve body so as to sequentially face the same injection hole. And it is characterized in that it is arranged.

[0009]

When the valve element is lifted, the fuel pool at the forefront in the lift direction of the plurality of fuel pools first faces the injection hole. Thereby, fuel is injected from the injection hole. Thereafter, when the valve body is further lifted, the valve body portion between the foremost fuel pool and the subsequent second fuel pool faces the injection hole. As a result, the fuel injection from the injection hole is interrupted or the injection amount decreases. Thereafter, when the valve body is further lifted, the second fuel reservoir faces the injection hole, and fuel is injected. Hereinafter, the same applies. Therefore, fuel is intermittently injected.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
0 will be described. FIGS. 1 and 3 to 8 show one embodiment of the present invention. FIG. 1 is an enlarged sectional view of a main part thereof, and FIG. 3 is a longitudinal sectional view of the whole. First, the overall configuration of the fuel injection nozzle N according to the present invention will be described with reference to FIG. 3. The fuel injection nozzle N includes a nozzle body 3. The nozzle body 3 includes a nozzle holder 31 and a nozzle 32 on a lower end surface of the nozzle holder 31.
And a nozzle body 33 fixed by the above. 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, and a nozzle holder 3 is formed from the lower end of the fuel hole 31a.
A spring housing hole 31b extending to the lower end surface of the first housing 1 is formed. Inside the spring receiving hole 31b, a valve element 6 described later is provided.
3 is housed in FIG. The high-pressure fuel is fed into the spring housing hole 31b 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. On the lower end surface where the valve sliding hole 33a opens,
A tapered valve seat 33b is formed so as to surround the valve slide hole 33a (see FIG. 1). A tapered surface 33c is formed on the outer peripheral surface of the lower end portion of the nozzle body 33, the diameter of which gradually decreases toward the bottom.

In the valve sliding hole 33a of the nozzle body 33,
The valve 6 is slidably inserted. The valve body 6 has a shaft portion 61 inserted through the valve sliding hole 33a, and a valve portion 62 connected to a lower end portion of the shaft portion 61 protruding from the valve sliding hole 33a.
It is composed of

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, whereby the valve portion 62 moves the valve seat 3.
3b. On the other hand, the shaft 61
Is pressed downward by the fuel fed into the spring receiving hole 31b, and when the pressing force by the fuel becomes larger than the urging force of the nozzle spring 5, the valve body 6
Lifting (moving downward) from 3b. In addition,
The fuel pressure at which the valve body 6 starts to lift is the valve opening pressure.

On the other hand, as shown in FIG. 1, the valve portion 62 has an outer peripheral surface formed with a tapered surface 62a which is continuous with the tapered surface 33c of the nozzle body 33 when seated on the valve seat 33b. Further, a tapered portion 62b is provided on the upper end surface of the valve portion 62.
Are formed. The taper angle of the tapered portion 62b is
It is smaller than the taper angle of the valve seat 33b. Therefore, the outer peripheral edge of the tapered portion 62b is the valve seat 33b.
Is seated in a state of abutting the outer peripheral edge of the vehicle.

The shaft portion 61 is formed with a fuel passage 63 extending downward from the upper end surface on the axis. Inside the fuel passage 63, the spring storage hole 31 is provided.
The fuel pumped to b flows in from the upper end opening.

The above structure is the same as that of the conventional fuel injection nozzle. However, the fuel injection nozzle N has the following structure so that fuel can be intermittently injected as the valve body 6 is lifted. Has been adopted.

That is, at the lower end of the nozzle body 33, four injection holes 34 are formed as shown in FIG. The injection holes 34 are spaced at equal intervals in the circumferential direction of the nozzle body 33, but are arranged at the same position in the axial direction. Each injection hole 34 has an inner end opening on the inner peripheral surface of the valve slide hole 33a, and an outer end opening near the outer peripheral edge of the valve seat 33b. The injection holes 34 may be formed in plurals other than one or four.

On the outer peripheral surface of the shaft portion 61, three annular grooves (fuel pools) 64a, 64b, 64c are formed. The width of each of the annular grooves 64a, 64b, 64c is equal to each other, and the opening inside the injection hole 34 (the valve sliding hole 33a
Of the valve slide hole 33a in the axial direction. Annular grooves 64a, 64b,
When the valve body 6 is seated on the valve seat 33b, the valve body 64c is arranged above the opening inside the injection hole 34, and furthermore, is arranged apart from each other in the axial direction of the valve body 6. The intervals between the annular grooves 64a, 64b, 64c are equal to each other and equal to or slightly larger than the width L. The uppermost annular groove 64c is arranged so as to face the entire opening inside the injection hole 34 when the valve body 6 is lifted to the maximum.

Each of the annular grooves 64a, 64b, 64c
Are connected to the fuel passage 6 through the communication holes 65a, 65b, 65c.
It is connected to 3. Communication holes 65a, 65b, 6
The cross-sectional areas 5c are set equal to each other and larger than the cross-sectional area of the injection hole 34. As a result, each communication hole 65
The flow resistance of the fuels a, 65b and 65c to the fuel is smaller than the flow resistance of the injection holes 34.

In the fuel injection nozzle having the above structure, when the pressure of the fuel fed from the fuel injection pump to the spring receiving hole 31b exceeds the initial valve opening pressure, the valve 6 starts to lift. Then, as shown in FIG. 4, the injection hole 34 first faces the annular groove 64a located at the lowermost side, and fuel is injected from the injection hole 34. When the valve body 6 is further lifted, the width L of the injection hole 34 is smaller than or equal to the interval between the annular grooves 64a and 64b. Therefore, as shown in FIG. The portion 61 is shielded by the outer peripheral surface. Therefore, the fuel injection is temporarily stopped. Less than,
As the valve body 6 is lifted, the injection hole 34 faces the annular groove 64b as shown in FIGS. 6, 7, and 8,
It is shielded by the outer peripheral surface of the shaft portion 61 between the annular groove 64b and the annular groove 64c, and faces the annular groove 64c. Therefore, as shown in FIG. 9, fuel injection is performed three times intermittently during one lift of the valve body 6.

Here, as the lift amount of the valve body 6 increases, the nozzle spring is compressed and its urging force increases, so that the fuel pressure also increases according to the lift amount. Therefore, not only the fuel injection amount increases as the fuel injection is performed later, but also the penetration increases and the particle diameter of the fuel decreases. Therefore, the fuel having the large and small particle diameters can be appropriately dispersed by the overtaking phenomenon of the fuel.
And reduction of combustion noise can be achieved, and at full load, smoke, NOx can be reduced, and fuel efficiency can be improved.

FIG. 2 shows another embodiment of the present invention. In this embodiment, the annular grooves 66a and 6a are provided.
6b, when the width of 66c (width in the axial direction of the shaft portion 61) was set to L _1, L _2, L _3, respectively, it is set to _{L 1 ≦ L 3 <L 2} . In addition, the communication holes 67a, 67b, 67
The sectional areas of c are S ₁ , S ₂ , and S ₃ , respectively.
Is defined as S ₁ <S ₃ <S <S ₂ . Since other configurations are the same as those of the above-described embodiment, the same portions are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment satisfying the above conditions, as shown in FIG. 10, when the injection hole 34 faces the annular groove 64b, that is, the second fuel injection amount becomes maximum and the penetration becomes maximum. Become. Therefore,
An appropriate distribution of the spray can be achieved by the first fuel overtaking phenomenon by the second fuel. Further, since the penetration at the time of the third fuel injection is smaller than the penetration at the time of the second fuel injection, the overtaking phenomenon of the fuel hardly occurs, but the fuel previously injected by the third fuel injection (partly) Has begun combustion) and the air is turbulent. Therefore, the utilization efficiency of air is improved, and the combustion efficiency can be further improved.

The present invention is not limited to the above-described embodiment, but can be appropriately made without departing from the scope of the invention. For example, in the above embodiment, the valve seat 3
Although 3b is formed such that its inner peripheral portion is located below the outer peripheral portion, the inner peripheral portion may be located above the outer peripheral portion as in the conventional fuel injection nozzle shown in FIG. .

The communication holes 65a,
Annular grooves 64a, 64b, 64c communicating with the fuel passage 63 via 65b, 65c (67a, 67b, 67c)
(66a, 66b, 66c) are formed, but the communication holes 65a, 65b, 65c (67a, 67b, 67c) are directly opened on the outer peripheral surface of the shaft portion 61, and the communication holes 65a, 6c are formed.
5b and 65c (67a, 67b and 67c)
May be directly opposed. In this case, the communication holes 65a, 65b, 65c (67a, 67b, 67
The outer end of c) functions as a fuel pool.

Further, in the above embodiment, the intervals between the annular grooves 64a, 64b, 64c (66a, 66b, 66c) are equal to each other, but may be different from each other. These intervals are determined by the annular grooves 64a, 64a.
b, 64c (66a, 66b, 66c)
It is determined in consideration of combustion efficiency, reduction of smoke, and the like. Alternatively, only two annular grooves may be formed without forming three annular grooves.

[0028]

As described above, according to the fuel injection nozzle of the present invention, while the injection hole is formed in the nozzle body, a plurality of fuel reservoirs communicating with the fuel passage are formed on the outer peripheral surface of the valve body. Since the injection hole and each fuel reservoir are sequentially opposed according to the lift of the valve body,
The fuel can be injected intermittently, so that a reduction in HC and a reduction in combustion noise can be achieved during idling, and a smoke,
Effects such as reduction of NOx and improvement of fuel efficiency can be obtained.

[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 is an enlarged sectional view showing a main part of another embodiment of the present invention.

FIG. 3 is a sectional view showing the entire embodiment shown in FIG. 1;

FIG. 4 is an enlarged sectional view of a main part showing a state when the valve body is lifted in the embodiment shown in FIG. 1;

FIG. 5 is an enlarged sectional view of a main part showing a state when the valve body is lifted in the embodiment shown in FIG. 1;

FIG. 6 is an enlarged sectional view of a main part showing a state when the valve body is lifted in the embodiment shown in FIG. 1;

FIG. 7 is an enlarged sectional view of a main part showing a state when the valve element is lifted in the embodiment shown in FIG. 1;

FIG. 8 is an enlarged sectional view of a main part showing a state when the valve body is lifted in the embodiment shown in FIG. 1;

FIG. 9 is a diagram showing fuel injection characteristics of the embodiment shown in FIG. 1;

FIG. 10 is a diagram showing fuel injection characteristics of the embodiment shown in FIG. 2;

FIG. 11 is a diagram showing fuel injection characteristics of the conventional fuel injection nozzle shown in FIG.

FIG. 12 is a cross-sectional view showing a main part of an example of a conventional fuel injection nozzle.

FIG. 13 is a cross-sectional view showing a state when the valve body of the fuel injection nozzle shown in FIG. 12 is lifted.

FIG. 14 is a cross-sectional view showing a state when the valve body of the fuel injection nozzle shown in FIG. 12 is lifted.

[Explanation of symbols]

 Reference Signs List 3 Nozzle body 33 Nozzle body 33a Valve sliding hole 33b Valve seat 34 Injection hole 6 Valve body 63 Fuel passage 64a Annular groove (fuel reservoir) 64b Annular groove (fuel reservoir) 64c Annular groove (fuel reservoir) 66a Annular groove (fuel reservoir) 66b annular groove (fuel pool) 66c annular groove (fuel pool)

Claims (1)

(57) [Scope of request for utility model registration] 1. A valve slide hole having one end opened to the outer surface is formed in the inside, and the valve slide hole is formed in the outer surface where the valve slide hole is opened.
A nozzle body formed with a valve seat surrounding the opening, and an end portion slidably provided in the valve slide hole, a fuel passage formed therein, and protruding outside from the valve slide hole. A valve body formed with a valve portion to be seated on the valve seat. One end of the valve body has an opening on an inner peripheral surface of the valve sliding hole, and the other end has the valve seat. A plurality of fuel reservoirs communicating with the fuel passage are formed on an outer peripheral surface of the valve body, and the plurality of fuel reservoirs are formed when the valve body lifts from the valve seat. Therefore, the fuel injection nozzle is arranged to be spaced apart from each other in the axial direction of the valve body so as to sequentially face the same injection hole.