JP5336451B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve used as a fuel injection valve for an engine.

  As this type of technology, the technology described in Patent Document 1 below is disclosed. This publication discloses a fuel injection valve that injects fuel, which has been swirled in a swirl chamber, from each fuel injection hole. The fuel injection hole of the fuel injection valve is formed in an injector plate having a plate thickness thinner than the inner diameter of the fuel injection hole.

Japanese Patent No. 3715253

By shortening the axial length with respect to the inner diameter of the fuel injection hole, the particle size of the injected fuel can be reduced. However, if the axial length is shorter than the inner diameter of the fuel injection hole, the strength of the plate may not be ensured.
The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a fuel injection valve capable of reducing the particle size of the fuel and ensuring the strength of the plate.

In order to achieve the above object, according to the present invention, a nozzle plate fixed to the swirl application chamber side is formed. The communication hole communicates with each swirl application chamber, and communicates with the communication hole and opens to the outside from the diameter of the communication hole. The fuel injection hole comprised from the larger diameter enlarged part was provided , and the fuel injection hole and the swirl provision chamber were formed coaxially .

  According to the present invention, the particle size of the fuel can be reduced and the strength of the plate can be ensured.

It is an axial sectional view of the fuel injection valve of Example 1. 3 is an enlarged cross-sectional view of the vicinity of a swirl chamber according to Embodiment 1. FIG. It is the top view which looked at the valve seat member of Example 1 from the axial direction other end side. It is the top view which looked at the nozzle plate of Example 1 from the axial direction. FIG. 3 is an enlarged cross-sectional view of a fuel injection hole part of Example 1. It is a figure which shows the top view of the fuel-injection hole formed in the cylindrical shape of Example 1, and the image of the flow of the fuel in a fuel-injection hole. It is a figure which shows the relationship between the axial length of the fuel injection hole of Example 1, and the fuel particle size injected from a fuel injection hole. It is a figure which shows the top view of the fuel injection hole which formed the enlarged diameter part of Example 1, and the image of the flow of the fuel in a fuel injection hole. 6 is an enlarged cross-sectional view of the vicinity of a swirl chamber according to Embodiment 2. FIG. It is an expanded sectional view of a fuel injection hole part of Example 2. It is an expanded sectional view near a swirl room of other examples. It is an expanded sectional view near a swirl room of other examples.

[Example 1]
The fuel injection valve 1 according to the first embodiment will be described.
[Configuration of fuel injection valve]
FIG. 1 is an axial sectional view of the fuel injection valve 1. The fuel injection valve 1 is used for an automobile engine or the like.
The fuel injection valve 1 includes a magnetic cylinder 2, a core cylinder 3 accommodated in the magnetic cylinder 2, a valve element 4 slidable in the axial direction, and a valve shaft formed integrally with the valve element 4. 5, a valve seat member 7 having a valve seat 6 that is closed by the valve body 4 when the valve is closed, a nozzle plate 8 having an injection hole through which fuel is injected when the valve is opened, and a direction in which the valve body 4 is opened when energized And an electromagnetic coil 9 to be slid and a yoke 10 for inducing magnetic flux lines.

The magnetic cylinder 2 is made of a metal pipe or the like formed of a magnetic metal material such as electromagnetic stainless steel, and is stepped as shown in FIG. 1 by using means such as deep drawing or pressing or grinding. It is integrally formed in a cylindrical shape. The magnetic cylinder 2 has a large-diameter portion 11 formed on one end side and a small-diameter portion 12 having a smaller diameter than the large-diameter portion 11 and formed on the other end side.
The small diameter portion 12 is formed with a thin portion 13 that is partially thinned. The small-diameter portion 12 includes a core tube housing portion 14 that houses the core tube body 3 on one end side from the thin wall portion 13, and a valve member 15 (valve 4, valve shaft 5, valve seat member on the other end side from the thin wall portion 13. 7) and is divided into a valve member accommodating portion 16 for accommodating. The thin portion 13 is formed so as to surround a gap portion between the core cylinder 3 and the valve shaft 5 in a state where the core cylinder 3 and the valve shaft 5 described later are accommodated in the magnetic cylinder 2. The thin wall portion 13 increases the magnetic resistance between the core tube housing portion 14 and the valve member housing portion 16, and magnetically blocks between the core tube housing portion 14 and the valve member housing portion 16.

The large diameter portion 11 constitutes a fuel passage 17 for sending fuel to the valve member 15, and a fuel filter 18 for filtering the fuel is provided at one end of the large diameter portion 11. A pump 47 is connected to the fuel passage 17. The pump 47 is controlled by a pump control device 54.
The core cylinder 3 is formed in a cylindrical shape having a hollow portion 19 and is press-fitted into the core cylinder housing portion 14 of the magnetic cylinder 2. The hollow portion 19 accommodates a spring receiver 20 fixed by means such as press fitting. A fuel passage 43 penetrating in the axial direction is formed at the center of the spring receiver 20.
The outer shape of the valve body 4 is formed in a substantially spherical shape, and has a fuel passage surface 21 cut in parallel with the axial direction of the fuel injection valve 1 on the circumference. The valve shaft 5 has a large-diameter portion 22 and a small-diameter portion 23 whose outer shape is smaller than the large-diameter portion 22.

The valve body 4 is integrally fixed to the tip of the small diameter portion 23 by welding. In addition, the black semicircle and black triangle in a figure have shown the welding location. A spring insertion hole 24 is formed at the end of the large diameter portion 22. A spring seat 25 having a smaller diameter than the spring insertion hole 24 is formed at the bottom of the spring insertion hole 24, and a stepped spring receiving portion 26 is formed. A fuel passage hole 27 is formed at the end of the small diameter portion 23. The fuel passage hole 27 communicates with the spring insertion hole 24. A fuel outflow hole 28 penetrating the outer periphery of the small diameter portion 23 and the fuel passage hole 27 is formed.
The valve seat member 7 includes a substantially conical valve seat 6, a valve body holding hole 30 formed on the one end side of the valve seat 6 so as to be substantially the same as the diameter of the valve body 4, and a diameter increasing toward the one end opening side. A formed opening 31 is provided.
On the other end side of the valve seat member 7, a plurality of swirl chambers 41 that give swirls (swirl flow) to the fuel and a fuel distribution chamber 42 that distributes the fuel to each swirl chamber 41 are formed.
The valve shaft 5 and the valve body 4 are accommodated in the magnetic cylinder 2 so as to be slidable in the axial direction. A coil spring 29 is provided between the spring receiver 26 and the spring receiver 20 of the valve shaft 5 to urge the valve shaft 5 and the valve body 4 to the other end side. The valve seat member 7 is inserted into the magnetic cylinder 2 so that the valve body 4 is seated on the valve seat 6, and is fixed to the magnetic cylinder 2 by welding.

A nozzle plate 8 is provided on the other end side of the valve seat member 7, and the nozzle plate 8 is fixed to the valve seat member 7 by welding. The nozzle plate 8 is formed with a fuel injection hole 44 through which the fuel swirled in the swirl chamber 41 is injected.
An electromagnetic coil 9 is inserted into the outer periphery of the core cylinder 3 of the magnetic cylinder 2. That is, the electromagnetic coil 9 is disposed on the outer periphery of the core cylinder 3. The electromagnetic coil 9 includes a bobbin 32 formed of a resin material and a coil 33 wound around the bobbin 32. The coil 33 is connected to the electromagnetic coil control device 55 via the connector pin 34. The electromagnetic coil control device 55 energizes the coil 33 of the electromagnetic coil 9 to energize the fuel injection valve 1 in accordance with the timing of injecting fuel into the combustion chamber calculated based on the information from the crank angle sensor that detects the crank angle. Open the valve.

The yoke 10 has a hollow through-hole, and has a large-diameter portion 35 formed on one end opening side, a medium-diameter portion 36 formed with a smaller diameter than the large-diameter portion 35, and a diameter smaller than the medium-diameter portion 36. It is composed of a small diameter portion 37 formed on the end opening side. The small diameter portion 37 is fitted on the outer periphery of the valve member housing portion 16. An electromagnetic coil 9 is accommodated on the inner periphery of the medium diameter portion 36. A connecting core 38 is disposed on the inner periphery of the large diameter portion 35.
The connecting core 38 is formed in a substantially C shape by a magnetic metal material or the like. The yoke 10 is connected to the magnetic cylinder 2 at the large-diameter portion 35 via the small-diameter portion 37 and the connecting core 38, that is, magnetically connected to the magnetic cylinder 2 at both ends of the electromagnetic coil 9. It becomes. A protector 52 for holding the O-ring 40 for connecting the fuel injection valve 1 to the intake port of the engine and protecting the tip of the magnetic cylinder is attached to the tip of the yoke 10 on the other end side.
When power is supplied to the electromagnetic coil 9 through the connector pin 34, a magnetic field is generated, and the valve body 4 and the valve shaft 5 are opened against the biasing force of the coil spring 29 by the magnetic force of the magnetic field.

As shown in FIG. 1 of the fuel injection valve 1, the intermediate diameter portion of the electromagnetic coil 9 and the yoke 10 is located up to the portion of the magnetic cylinder 2 excluding one end portion of the large diameter portion 11 and the electromagnetic coil 9 installation position of the small diameter portion 12. 36, the outer periphery of the connecting core 38 and the large-diameter portion 35, the outer periphery of the large-diameter portion 35, the outer periphery of the medium-diameter portion 36, and the outer periphery of the connector pin 34 are covered with a resin cover 53. The tip of the connector pin 34 is formed by opening a resin cover 53 so that the connector of the control unit can be inserted.
An O-ring 39 is provided on the outer periphery of one end of the magnetic cylinder 2, and an O-ring 40 is provided on the outer periphery of the small diameter portion 37 of the yoke 10.

[Configuration of swirl room]
FIG. 2 is an enlarged sectional view of the vicinity of the swirl chamber 41 of the fuel injection valve 1. 3 is a plan view of the valve seat member 7 as viewed in the direction of arrow A in FIG.
A swirl chamber 41 and a fuel distribution chamber 42 are formed on the other end side of the valve seat member 7 (see FIG. 3). The fuel distribution chamber 42 is formed in a circular concave shape on the concentric axis of the valve seat member 7. When the valve is opened, the fuel is guided to the fuel distribution chamber 42.
The swirl chamber 41 includes an introduction passage 41a and a swirl grant chamber 41b. The introduction passage 41a is formed to extend radially from the fuel distribution chamber. A swirl imparting chamber 41b is formed at the tip of the radially extending introduction passage 41a. The swirl imparting chamber 41b is formed in a circular concave shape. The introduction passage 41a is connected to the swirl application chamber 41b on the tangent line of the swirl application chamber 41b.

[Configuration of nozzle plate]
FIG. 4 is a plan view of the nozzle plate 8 as viewed from the axial direction side. In FIG. 4, the positions of the swirl chamber 41 and the fuel distribution chamber 42 are indicated by dotted lines. FIG. 5 is an enlarged cross-sectional view of the fuel injection hole 44 portion.
The nozzle plate 8 is formed with fuel injection holes 44 penetrating in the axial direction. The fuel injection hole 44 includes a communication hole 44a that communicates with the swirl chamber 41, and a diameter-expanded portion 44b that communicates with the communication hole 44a and opens to the outside, and is larger in diameter than the communication hole 44a. .
The enlarged diameter portion 44b is enlarged in a conical shape from the communication hole 44a side toward the opening. The opening angle δ of the enlarged diameter portion 44b is formed to be 45 degrees or more and 120 degrees or less.
The communication hole 44a is formed smaller than the diameter of the swirl application chamber 41b. In FIG. 5, the axial length L of the communication hole 44 a is formed to be ½ or less, more preferably ¼ or less of the plate thickness T of the nozzle plate 8. Alternatively, the axial length L of the communication hole 44a is formed to be not more than twice (2 × D) the diameter of the communication hole 44a, more preferably not more than the diameter D of the communication hole 44a.

[Action]
Next, the operation of the fuel injection valve 1 of the first embodiment will be described.
(Relationship between axial length of fuel injection hole and fuel particle size)
6 is a plan view of the fuel injection hole 44 formed in a cylindrical shape (FIG. 6A) and an image of the fuel flow in the fuel injection hole 44 (FIG. 6B). FIG. 7 is a diagram showing the relationship between the axial length of the fuel injection hole 44 and the particle size of the fuel injected from the fuel injection hole 44. FIG. 7 (a) shows a conventional fuel injection hole 44, that is, a fuel injection hole 44 formed in a cylindrical hollow portion having no enlarged diameter portion. Here, the axial length of the fuel injection hole 44 is L, and the diameter of the fuel injection hole 44 is D. FIG. 7B is a graph showing the change rate of the particle size of the fuel injected from the fuel injection hole 44 with respect to L / D. FIG. 7B shows the change rate of the particle size based on the particle size of the fuel when L / D is 2.0.

  Here, fuel atomization will be described. When the valve is opened, fuel is supplied to the fuel distribution chamber 42 from between the valve body 4 and the valve seat 6. The fuel supplied to the fuel distribution chamber 42 flows into the swirl application chamber 41b through the introduction passage 41a. The fuel that has flowed into the swirl imparting chamber 41b swirls in the swirl imparting chamber 41b and is injected to be supplied to the fuel injection hole 44 while having swirling energy. The fuel having the turning energy is injected while turning along the wall portion of the fuel injection hole 44. Therefore, the fuel injected from the fuel injection hole 44 is a combined vector Z of the vector X in the axial direction of the fuel injection hole 44 and the vector Y in the peripheral tangential direction of the fuel injection hole 44 as shown in FIG. Hold and scatter. The fuel spray immediately after being injected from the fuel injection hole 44 spreads conically in a thin liquid film state by the edge part (E part in FIG. 6) at the opening of the fuel injection hole 44. Thereafter, the fuel in the liquid film state is separated into droplets that are atomized.

As a result, fuel vaporization can be promoted, and in particular, generation of nitrogen oxides and the like during low temperature starting can be reduced.
As the particle size of the fuel is smaller, the vaporization of the fuel can be promoted. However, as shown in FIG. 7, it is understood that the particle size is smaller as L / D is smaller. As described above, the fuel spray immediately after being injected from the fuel injection hole 44 spreads conically in a thin liquid film state by the edge part (E part in FIG. 6) of the opening part of the fuel injection hole 44. The thinner the liquid film, the smaller the droplet size. In order to make the liquid film thinner, the turning force of the fuel at the opening of the fuel injection hole 44 must be large. However, if the axial length L of the fuel injection hole 44 in FIG. Friction with the inner wall of the fuel increases, and the turning force of the fuel is reduced. In other words, in order to reduce the particle size of the droplet, the axial length of the fuel injection hole 44 may be shortened.
For this purpose, it is necessary to reduce the thickness of the nozzle plate 8. However, the thickness of the nozzle plate 8 cannot be sufficiently reduced in terms of ensuring the strength.

(Fuel atomization)
Therefore, in the fuel injection valve 1 of the first embodiment, the cylindrical communication hole 44a that connects the fuel injection hole 44 to the swirl chamber 41, and the fuel injection hole 44 are communicated with each other and gradually toward the outside of the fuel injection valve 1. The enlarged diameter portion 44b is larger than the diameter of the communication hole 44a opened to the outside in the expanded state. In the first embodiment, the enlarged diameter portion 44b is enlarged toward the outside of the fuel injection hole 44 over the entire circumference. For example, the communication hole 44b on the center side of the nozzle plate 8 is formed straight in the axial direction. Also good.
FIG. 8 is a plan view of the fuel injection hole 44 formed in a cylindrical shape (FIG. 8A) and an image of the fuel flow in the fuel injection hole 44 (FIG. 8B). The fuel having the swirling energy passes while swirling along the wall of the communication hole 44a (the arrow in FIG. 8B), and the edge portion in the opening of the communication hole 44a on the enlarged diameter portion 44b side (in FIG. 8). E portion) spreads conically in a thin liquid film state (arrow in FIG. 8). Since the enlarged diameter portion 44b is larger than the communication hole 44a, it is possible to prevent the enlarged diameter portion 44b from coming into contact with the conical liquid film. That is, in the fuel injection hole 44, the fuel is in direct contact with only the communication hole 44a and hardly in contact with the enlarged diameter portion 44b. Therefore, the friction between the fuel and the inner wall of the fuel injection hole 44 can be reduced.

Therefore, the fuel turning force at the opening of the communication hole 44a can be increased, and a thin liquid film can be formed by the edge portion at the opening of the communication hole 44a. Therefore, the particle size of the fuel droplets can be reduced, and fuel vaporization can be promoted.
Further, since the axial length of the communication hole 44a can be set regardless of the plate thickness of the nozzle plate 8, the plate thickness of the nozzle plate 8 can be secured and the strength of the nozzle plate 8 can be maintained.

Further, in the fuel injection valve 1 of the first embodiment, the axial length of the communication hole 44a is formed to be shorter than one half of the nozzle plate 8.
Therefore, the particle size of the fuel can be reduced while ensuring the strength of the nozzle plate 8.
Further, in the fuel injection valve 1 of the first embodiment, the axial length of the communication hole 44a is formed to be shorter than a quarter of the nozzle plate 8.
Therefore, the particle size of the fuel can be reduced while ensuring the strength of the nozzle plate 8.
Further, in the fuel injection valve 1 of the first embodiment, the axial length of the communication hole 44a is formed to be equal to or smaller than the diameter of the communication hole 44a.
Therefore, the particle size of the fuel can be reduced while ensuring the strength of the nozzle plate 8.

[effect]
The effects of the fuel injection valve 1 of the first embodiment are listed below.
(1) A valve body 4 slidably provided, a valve seat 6 on which the valve body 4 sits when the valve is closed is formed on one end side, and is formed on the other end side of the valve seat member 7. A plurality of swirl imparting chambers 41b for imparting a swirl to the fuel, a nozzle plate 8 fixed to the swirl imparting chamber 41b side, a communication hole 44a communicating with the swirl imparting chamber 41b, and a communication hole 44a. A fuel injection hole 44 that is open to the outside and includes a large-diameter portion 44b that is larger than the diameter of the communication hole 44a is provided.
Therefore, the particle size of the fuel can be reduced, the plate thickness of the nozzle plate 8 can be secured, and the strength of the nozzle plate 8 can be maintained.

(2) The communication hole 44a has a diameter smaller than that of the swirl application chamber 41b.
Therefore, the particle size of the fuel can be reduced.
(3) The axial length of the communication hole 44a is smaller than the plate thickness of the nozzle plate 8.
Therefore, the particle size of the fuel can be reduced while ensuring the strength of the nozzle plate 8.
(4) The axial length of the communication hole 44a is made smaller than the diameter of the communication hole 44a.
Therefore, the particle size of the fuel can be reduced while ensuring the strength of the nozzle plate 8.

(5) The axial length of the communication hole 44a is formed to be smaller than twice the diameter of the communication hole 44a.
Therefore, the particle size of the fuel can be reduced while ensuring the strength of the nozzle plate 8.
(6) The enlarged diameter portion 44b is formed in a conical shape, and the opening angle of the cone of the enlarged diameter portion 44b is set to 45 degrees or more and 120 degrees or less.
Therefore, it is possible to suppress the liquid film spreading conically from the communication hole 44a from coming into contact with the enlarged diameter portion 44b, and the friction between the fuel and the inner wall of the fuel injection hole 44 can be reduced.

[Example 2]
The fuel injection valve 1 according to the second embodiment will be described. In the fuel injection valve 1 according to the first embodiment, the enlarged diameter portion 44b of the fuel injection hole 44 is formed so as to increase in a conical shape from the communication hole 44a side toward the opening. The second embodiment is different from the fuel injection valve 1 of the first embodiment in that the enlarged diameter portion b of the fuel injection hole 44 is formed in a cylindrical shape. FIG. 9 is an enlarged cross-sectional view of the vicinity of the swirl chamber 41 of the fuel injection valve 1. FIG. 10 is an enlarged cross-sectional view of the fuel injection hole 44 portion.
The nozzle plate 8 is formed with fuel injection holes 44 penetrating in the axial direction. The fuel injection hole 44 includes a communication hole 44a that communicates with the swirl chamber 41, and a diameter-expanded portion 44b that communicates with the communication hole 44a and opens to the outside, and is larger in diameter than the communication hole 44a. .
The enlarged diameter portion 44b is formed in a cylindrical shape having a larger diameter than the communication hole 44a. The diameter of the communication hole 44a is D, the axial length of the communication hole is L, the thickness of the nozzle plate 8 is T, and the line connecting the opening end of the communication hole 44a and the opening end of the enlarged diameter portion 44b is the axial direction of the fuel injection hole 44 When the angle formed with respect to is θ, the diameter d of the enlarged diameter portion 44b is
d = D + 2 (TL) tanθ (22.5 ≦ θ ≦ 60)
It is formed to become.

[Action]
Since the diameter-expanded portion 44b is larger in diameter than the communication hole 44a, it is possible to suppress the diameter-expanded portion 44b from coming into contact with the conical liquid film. That is, in the fuel injection hole 44, the fuel is in direct contact with only the communication hole 44a and hardly in contact with the enlarged diameter portion 44b. Therefore, the friction between the fuel and the inner wall of the fuel injection hole 44 can be reduced.

[effect]
(7) The enlarged diameter portion 44b is formed in a cylindrical shape, where the axial length of the communication hole 44a is L, the diameter of the communication hole 44b is D, and the plate thickness of the nozzle plate 9 is T, the cylindrical diameter of the enlarged diameter portion 44a. Diameter d
d = D + 2 (TL) tanθ (22.5 ≦ θ ≦ 60)
It formed so that it might become.
Therefore, it is possible to suppress the liquid film spreading conically from the communication hole 44a from coming into contact with the enlarged diameter portion 44b, and the friction between the fuel and the inner wall of the fuel injection hole 44 can be reduced.

[Other Examples]
As described above, the present invention has been described based on the first embodiment. However, the specific configuration of each invention is not limited to each embodiment, and even if there is a design change or the like without departing from the gist of the invention. Are included in the present invention.
For example, the axial length of the communication hole 44a of the fuel injection hole 44 may be as short as long as it is ½ or ¼ or less. FIG. 11 is an enlarged cross-sectional view of the vicinity of the swirl chamber 41 of the fuel injection valve 1. As shown in FIG. 11, the axial length of the communication hole 44a may be made as short as possible so as to approach zero.
In the fuel injection valve 1 of the first embodiment, the swirl chamber 41 is formed in the valve seat member 7, but the intermediate plate 50 may be provided to form the swirl chamber 41 in the intermediate plate 50. FIG. 12 is an enlarged cross-sectional view of the vicinity of the swirl chamber 41 of the fuel injection valve 1. As shown in FIG. 12, the swirl chamber 41 is formed in the intermediate plate 50, and the intermediate plate 50 is welded to the valve seat member 7 together with the nozzle plate 8.

1 Fuel injection valve
4 Disc
7 Valve seat member
8 Nozzle plate
41 Swirl room
44 Fuel injection hole
44a Communication hole
44b Expanded part

Claims (8)

A valve body slidably provided;
A valve seat member formed on one end side of a valve seat on which the valve body sits when the valve is closed;
A plurality of swirl application chambers provided on the other end side of the valve seat member for applying a swirl to the fuel;
Formed in a nozzle plate fixed to the swirl application chamber side, communicating with each swirl application chamber, and a diameter-enlarged portion communicating with the communication hole and opening to the outside and larger than the diameter of the communication hole; A fuel injection hole comprising:
Provided ,
The fuel injection valve, wherein the fuel injection hole and the swirl application chamber are formed coaxially . A valve body slidably provided;
A valve seat member formed on one end side of a valve seat on which the valve body sits when the valve is closed;
A plurality of swirl application chambers provided on the other end side of the valve seat member for applying a swirl to the fuel;
An intermediate plate fixed to the swirl chamber,
A fuel injection hole formed in the intermediate plate and communicating with each of the swirl application chambers, and a diameter-enlarged portion that communicates with the communication hole and opens to the outside and is larger than the diameter of the communication hole. A nozzle plate formed with
Provided ,
The fuel injection valve, wherein the fuel injection hole and the swirl application chamber are formed coaxially . The fuel injection valve according to claim 1 or 2,
The diameter of the said communicating hole is smaller than the diameter of the said swirl provision chamber, The fuel injection valve characterized by the above-mentioned. The fuel injection valve according to any one of claims 1 to 3,
The fuel injection valve according to claim 1, wherein an axial length of the communication hole is smaller than a plate thickness of the nozzle plate. The fuel injection valve according to any one of claims 1 to 4,
The fuel injection valve according to claim 1, wherein an axial length of the communication hole is smaller than a diameter of the communication hole. The fuel injection valve according to any one of claims 1 to 4,
The fuel injection valve according to claim 1, wherein an axial length of the communication hole is smaller than twice a diameter of the communication hole. The fuel injection valve according to claim 5 or 6,
The fuel injection valve according to claim 1, wherein the enlarged diameter portion is formed in a conical shape, and an opening angle of the cone of the enlarged diameter portion is set to 45 degrees or more and 120 degrees or less. The fuel injection valve according to claim 1, wherein
The enlarged diameter portion is formed in a cylindrical shape, and when the axial length of the communication hole is L, the diameter of the communication hole is D, and the plate thickness of the nozzle plate is T, the cylindrical diameter d of the enlarged diameter portion is
d = D + 2 (TL) tanθ (22.5 ≦ θ ≦ 60)
A fuel injection valve characterized by that.

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