JP3182057B2 - Fuel injection valve - 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 valve which injects fuel flowing in a valve body while giving a swirling flow.

[0002]

2. Description of the Related Art In recent years, a system for directly injecting fuel into an engine cylinder for the purpose of achieving low fuel consumption, low emission, and high output has been considered. The fuel injection valve used in this system has an improved atomization mechanism in order to improve atomization performance. For example, as shown in FIG.
1 accommodates a needle valve 12 and a valve body 11
By opening and closing the upper opening of the fuel injection chamber 13 formed at the lower end of the fuel injection chamber 13 with the needle valve 12, fuel is injected / stopped from the injection hole 14 formed in the spherical bottom surface of the fuel injection chamber 13. I have. Further, in order to guide the opening / closing stroke of the needle valve 12, the needle valve 12
A guide portion 15 that is slidably fitted to the inner peripheral surface of the valve body 11 is integrally formed at a lower portion of the guide portion 1.
An inclined groove 16 serving as a fuel flow path is formed on the outer peripheral surface of the fuel cell 5,
When the fuel passes through the inclined groove 16, a swirling flow is given to the fuel, and the atomization of the fuel injected from the injection holes 14 is promoted.

[0003]

However, in the above conventional structure, the pressure of the fuel swirling flow passing through the inclined groove 16 acts on the needle valve 12 in the valve closing direction, so that the needle valve 12 is opened (injection operation). ) Has the disadvantage that the response is poor.

Further, since the swirling flow of the fuel swirling along the peripheral surface of the fuel injection chamber 13 advances toward the center of the spherical bottom surface of the fuel injection chamber 13, the swirling energy of the fuel is reduced to the center of the bottom surface of the fuel injection chamber 13. Is the largest. However, in the above-mentioned conventional configuration, since the center line P of the injection hole 14 is designed to coincide with the center C of the fuel injection chamber 13, the position of the inlet of the injection hole 14 is shifted from the center of the bottom surface of the fuel injection chamber 13, The turning energy of the fuel cannot be effectively used for atomizing the fuel.

The injection hole 1 is provided at the lower end of the valve body 11.
When forming 4, a hole is formed from the outside of the valve body 11 toward the fuel injection chamber 13. However, in the above-described conventional configuration, since the lower end outer surface of the valve body 11 has a spherical convex surface, Not only is it difficult to form a hole, but the edge shape of the outlet side edge of the injection hole 14 tends to be non-uniform, and the spray shape is poor.

The present invention has been made in view of such circumstances, and accordingly, has as its object to provide a fuel injection valve capable of improving both atomization performance, workability, and responsiveness of injection operation. It is in.

[0007]

In order to achieve the above object, a fuel injection valve according to a first aspect of the present invention includes a needle valve housed in a valve body to which fuel is supplied, and a needle valve fitted in the valve body. The needle valve has a needle through hole through which the needle valve slidably penetrates, and the valve
A swirler for providing a swirling flow to the fuel flowing in the body, and a fuel injection formed to introduce the swirling flow of the fuel downstream of the valve seat of the needle valve in the valve body and having a spherical concave bottom surface. A chamber, an injection hole formed in the valve body so as to penetrate from the center of the bottom surface of the fuel injection chamber to the outside, and an injection hole formed in the valve body at a right angle to an outlet side of the injection hole. With a flat part, the inlet side edge of the injection hole is rounded,
The outlet side edge of the injection hole is formed to have a right-angled edge .

Further, as in claim 2, the inner diameter of the swirler may be configured to have fitted a cylindrical sliding member constituting the needle through-hole.

Furthermore, as according to claim 3, wherein the constructed as the lower end surface of the swirler in the vicinity of the valve seat portion of the needle valve and the lower inner surface of the valve body is in close contact, formed on the lower end surface of said swirler A flow path that gives a swirling flow to the fuel may be configured by the groove. Claim 4
As described above, the needle valve may be provided with a guide portion slidably fitted to the inner peripheral surface of the valve body near the upstream side of the swirler.

[0010]

According to the first aspect of the present invention, the swirler for imparting swirling flow to the fuel is a separate component from the needle valve, and the needle valve is slidably penetrated through the needle through hole formed in the swirler. ing. For this reason, the pressure of the fuel swirl flow acting on the needle valve in the valve closing direction becomes significantly smaller than in the conventional example shown in FIG. 8, and the responsiveness of the needle valve opening operation (injection operation) is improved. Further, since the inlet of the injection hole is located at the center of the bottom surface of the fuel injection chamber, the inlet of the injection hole is located at a position where the swirling energy of the fuel swirling in the fuel injection chamber is maximized, and the turning energy of the fuel is effective. Used for fuel atomization. In addition, since a flat portion is formed at a right angle to the injection hole on the outlet side of the injection hole, when forming the injection hole at the lower end of the valve body, it is possible to perform drilling on the flat portion. Drilling can be easily performed, and the edge shape of the outlet side edge of the injection hole can be easily formed into a sharp shape suitable for wide-angle spraying.

[0011]

[0012] Moreover, in claim 1, by rounding the inlet side edge portion of the injection holes, contraction in the flow of fuel is prevented from occurring at the inlet side edge portion of the injection hole, fuel The flow of fuel from the injection chamber into the injection hole becomes smooth. Furthermore, since the outlet side edge of the injection hole has a right-angled edge,
The atomization of the fuel by the edge of the outlet side edge of the injection hole is promoted.

By the way, when the outer diameter portion of the swirler is press-fitted and fixed to the valve body, and the needle valve is slidably inserted into the needle through hole of the inner diameter portion of the swirler,
Since the surface hardness of the outer diameter part (press-fit part) of the swirler needs to be low for press-fitting, the inner diameter part (needle through-hole) of the swirler requires cutting for clearance management. It is necessary to increase the surface hardness. Therefore, in the case where the swirler is formed of one part, the heat treatment for making the surface hardness of the inner and outer diameters higher and lower is troublesome.

[0014] Therefore, in claim 2, constitutes an inner diameter portion of the swirler as separate parts (cylindrical sliding member) by fitting the cylindrical sliding member to the inside diameter portion of the swirler, and out of the swirler Eliminates the need for a troublesome heat treatment for increasing or decreasing the surface hardness of the diameter. In other words, a sliding member that needs cutting processing for clearance management is formed of a material having a high hardness, a swirler press-fit into the valve body is formed of a material having a lower hardness than the sliding member, and the inner diameter portion of the swirler is formed. What is necessary is just to press-fit a sliding member into a unit and to integrate it.

According to a third aspect of the present invention, the lower end surface of the swirler is brought into close contact with the lower inner surface of the valve body in the vicinity of the valve seat of the needle valve, and the swirler provides a swirl flow to the fuel by a groove formed in the lower end surface. Is configured. This facilitates the processing of the flow path (groove) that gives the swirling flow to the fuel, reduces the fuel stagnation volume between the flow path and the injection hole, and reduces atomization failure at the beginning of injection.

Further, in the fourth aspect , since the guide portion formed on the needle valve has a function of guiding the opening and closing stroke of the needle valve, it is not necessary to provide this guide function to the swirler. For this reason, it is possible to increase the clearance between the inner diameter portion (needle through hole) of the swirler and the needle valve to such an extent that fuel leakage does not occur. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. First, the configuration of the entire fuel injection valve is shown in FIG.
It will be described based on. A solenoid coil 2 wound around a spool 22 is provided inside a housing 21 of the fuel injection valve.
3 is attached. In the inner diameter portion of the spool 22,
A cylindrical core 24 also serving as a fuel inflow pipe is fitted, and a flange 25 formed at an intermediate portion of the cylindrical core 24 is caulked and fixed to an upper edge of the housing 21. A fuel pipe (not shown) is provided at the upper end of the cylindrical iron core 24.
The fuel connector 26 is connected to the fuel connector 26, and a filter 27 is mounted inside the fuel connector 26. An electrical connector 28 made of plastic is provided on the flange portion 25 of the cylindrical core 24, and the solenoid coil 23 is inserted through a connector pin 29 provided on the electrical connector 28.
Is energized.

An adjust pipe 30 and a spring 31 are mounted inside the cylindrical core 24 so that the cylindrical core 2
The movable core 32 disposed below the movable core 4 is urged downward by a spring 31. On the other hand, a valve body 34 is caulked and fixed to the lower edge of the housing 21 via a spacer 33. A needle valve 35 is vertically movably housed in the valve body 34, and the upper end of the needle valve 35 passes through the spacer 33 and is connected to the movable core 32. Needle valve 35
The stopper 36 located near the lower part of the spacer 33
When the solenoid coil 23 is energized, the movable core 32 is attracted upward against the spring force of the spring 31, and the needle valve 35 is moved by the stopper 36 to the spacer 3.
The fuel injection chamber 43 is slid upward until the fuel injection chamber 3 comes into contact with the fuel injection chamber 3, thereby opening a top opening of a fuel injection chamber 43 described later.

Next, the needle valve 35 will be described with reference to FIG.
The structure of the atomizing mechanism will be described. A cylindrical swirler 37 is press-fitted and fixed to a lower portion in the valve body 34, and a lower portion of the needle valve 35 is slidably inserted in an inner diameter portion (a needle through-hole 38) of the swirler 37 in a vertical direction. A fuel introduction groove 39 for introducing fuel downward is formed on the outer periphery of the swirler 37, and an annular swirl chamber 40 is formed on the inner peripheral side of the lower end of the swirler 37. Furthermore,
The swirler 37 has a swirl chamber 40 from the fuel introduction groove 39.
One or a plurality of swirl holes 41 for introducing fuel into the swirl chamber 40 are formed so as to extend in a tangential direction of the swirl chamber 40, and when the fuel flows into the swirl chamber 40 through the swirl hole 41, a swirling flow is generated in the fuel. Is to be given.

The swirl chamber 40 is provided with the needle valve 3
The fuel injection chamber 43 is formed downstream of the valve seat 42 at the lower end of the needle valve 35. The fuel injection chamber 43 is formed at the downstream side of the valve seat 42. It is opened and closed by a part.
The fuel injection chamber 43 is formed in a tapered shape such that the inner surface gradually decreases in opening area toward the bottom surface (a taper angle is preferably, for example, 15 ° to 30 °), and the bottom surface of the fuel injection chamber 43 has a spherical concave surface. Is formed. An injection hole 44 is formed at the lower end of the valve body 34 so as to penetrate the fuel injection chamber 43 from the bottom center (lowest point) of the fuel injection chamber 43 to the outside.
The center of the bottom of 3 and the center of the entrance of the injection hole 44 coincide with each other. A flat portion 45 is formed on the outlet side of the injection hole 44 in the valve body 34 at right angles to the injection hole 44. The inlet side edge of the injection hole 44 is formed in an R shape (rounded shape), and the outlet side edge of the injection hole 44 is formed as a right-angled edge.

When the solenoid coil 23 is energized, the fuel injection valve constructed as described above sucks the movable core 32 upward against the spring force of the spring 31 to slide the needle valve 35 upward, and The upper opening of the injection chamber 43 is opened. Thereby, the fuel pressure-fed into the valve body 34 flows into the swirl chamber 40 through the swirl hole 41 of the swirler 37, and flows into the fuel injection chamber 43 while turning inside the swirl chamber 40. The fuel that has flowed into the fuel injection chamber 43 flows toward the center of the bottom while rotating along the peripheral surface of the fuel injection chamber 13, and
From the outside.

In this case, since the inlet of the injection hole 44 is located at the center (lowest point) of the bottom surface of the fuel injection chamber 43, the injection hole is located at a position where the swirling energy of the fuel swirling in the fuel injection chamber 43 becomes maximum. The inlet of 44 is located, and the turning energy of the fuel is effectively used for atomizing the fuel. Moreover, since the inner surface of the fuel injection chamber 43 is formed in a tapered shape in which the opening area gradually decreases toward the bottom surface side, the swirling flow of the fuel flowing along the inner surface of the fuel injection chamber 43 is centered on the bottom surface. (Injection hole 4
4), and the loss of fuel swirling energy in the fuel injection chamber 43 can be reduced. In addition, since the inlet-side edge of the injection hole 44 has an R-shape, the flow of the fuel is prevented from being contracted at the inlet-side edge of the injection hole 44, and the fuel injection chamber 43 is formed.
Therefore, the flow of fuel from the nozzle into the injection hole 44 becomes smooth, and the loss of energy at the inlet side edge of the injection hole 44 can be reduced. Further, since the outlet side edge of the injection hole 44 has a right-angled edge, the atomization of the fuel by the edge of the outlet side edge of the injection hole 44 is promoted, and the outlet hole 44 has a conical shape from the outlet. Spreading wide-angle spraying is possible (when the exit side edge of the injection hole 44 has an R-shape, the spraying angle becomes extremely narrow and atomization is hindered). By the synergistic effect of the above actions, the atomization performance is remarkably improved as compared with the related art, and it is possible to cope with low fuel consumption, low emission, and high output.

The volume of the fuel injection chamber 43 can be reduced by forming the inner side surface of the fuel injection chamber 43 into a tapered shape in which the opening area gradually decreases toward the bottom surface side. As a result, the amount of fuel remaining in the fuel injection chamber 43 before the start of injection is reduced, so that the fuel injection chamber 43
The amount of fuel that is pushed out of the chamber and becomes poor atomization is reduced, and the poor atomization at the beginning of injection is reduced.

On the other hand, a swirler 37 for giving a swirling flow to the fuel
Is a separate component from the needle valve 35, and since the needle valve 35 is slidably penetrated through the needle through hole 38 formed in the swirler 37, the fuel swirl acting in the valve closing direction with respect to the needle valve 35 The flow pressure is significantly smaller than in the conventional example shown in FIG.
The responsiveness of the opening operation (injection operation) of No. 5 is improved. That is, conventionally, as shown in FIG. 8, a portion (guide portion 15) corresponding to the swirler is formed integrally with the needle valve 12, so that the pressure of the fuel swirling flow is reduced by the needle valve 1.
However, in the above embodiment, the pressure of the fuel swirling flow acting on the swirler 37 does not directly act on the needle valve 35, and the injection operation is not performed. There is no need to reduce responsiveness.

Further, the injection hole 44 is provided at the outlet side of the injection hole 44.
Is formed at a right angle to the flat portion 45, the flat portion 45 can be perforated when the injection hole 44 is formed at the lower end of the valve body 34. It is easy and the processing accuracy can be improved, and the edge shape of the outlet side edge of the injection hole 44 can be easily processed into a sharp shape suitable for wide-angle spraying, contributing to the improvement of product quality. it can.

FIG. 3 shows a second embodiment of the present invention. The difference from the first embodiment lies in the shape of the swirler 50. The swirler 37 of the first embodiment described above has the swirl hole 41 inclined in the vertical direction, while the swirler 50 of the second embodiment has one or a plurality of swirl holes 51 formed horizontally. By making the swirl hole 51 communicate with the swirl chamber 52 from the tangential direction, a swirling flow stronger than in the first embodiment is generated.

In the first and second embodiments,
The outer diameter portions of the swirlers 37 and 50 are press-fitted and fixed to the valve body 34, and the needle valve 35 is slidably penetrated through the needle through hole 38 of the inner diameter portion of the swirlers 37 and 50. In this configuration, the surface hardness of the outer diameter portions of the swirlers 37 and 50 needs to be reduced for press-fitting, whereas the inner diameter portions of the swirlers 37 and 50 (the needle through-hole 3) are required.
In the case of 8), since a cutting process is required for clearance management, it is necessary to increase the surface hardness. Therefore, when the swirlers 37 and 50 are formed by one part, the heat treatment for making the surface hardness of the inner and outer diameters higher and lower is troublesome, and the workability is not very good.

In order to solve this disadvantage, the third type shown in FIG.
In the embodiment and the fourth embodiment shown in FIG.
The inner diameter part (sliding members 57, 58) of No. 6 is constituted by a separate part,
The tubular sliding members 57, 58 forming the needle through hole 38 are fitted to the inner diameter portions of the swirlers 55, 56. Here, the third embodiment shown in FIG. 4 corresponds to the first embodiment shown in FIG. 2, and the fourth embodiment shown in FIG. 5 corresponds to the second embodiment shown in FIG. In each embodiment, the sliding members 57 and 58 that require cutting for clearance management are formed of a material having high hardness, and the swirlers 55 and 56 that are pressed into the valve body 34 are formed by the sliding members 57 and 58. The swirlers 55 and 56 are formed of a material having low hardness, and the outer diameters of the swirlers 55 and 56 are press-fitted and fixed to the valve body 34.
The sliding members 57 and 58 are press-fitted and fixed to the inner diameter portion of the 56, and the needle valve 35 is slidably penetrated through the needle through hole 38 of the inner diameter of the sliding members 57 and 58. With such a configuration, a troublesome heat treatment for increasing or decreasing the surface hardness of the inner and outer diameters of the swirlers 55 and 56 becomes unnecessary, and the workability can be improved.

On the other hand, in the fifth embodiment of the present invention shown in FIGS. 6 and 7, the lower end surface of the swirler 60 is brought into close contact with the lower inner surface of the valve body 34 near the valve seat 42 of the needle valve 35, and One or a plurality of grooves 61 formed on the lower end surface constitute a flow path for giving a swirling flow to the fuel. Thereby, the flow path (groove 6) that gives a swirling flow to the fuel
The processing of 1) is facilitated, and the volume of the swirl chamber 62 formed on the inner peripheral side of the lower end of the swirler 60 can be reduced, so that the fuel retention volume between the groove 61 and the injection hole 44 can be reduced. Therefore, it is possible to reduce atomization failure at the initial stage of injection.

Further, in the fifth embodiment, the needle valve 35 is provided with a valve body 3 near the upstream side of the swirler 60.
A guide portion 63 slidably fitted to the inner peripheral surface of the needle valve 35 is integrally formed.
The lower end is aligned with the valve seat 42 to ensure the sealing performance when the valve is closed. In this configuration, the guide portion 63 formed on the needle valve 35
Therefore, it is not necessary to provide the swirler 60 with this guide function.
For this reason, the inner diameter portion of the swirler 60 (the needle through hole 3
8) and the clearance between the needle valve 35 can be increased, and the processing accuracy of the swirler 60 can be afforded, and processing can be facilitated. However, if the clearance between the swirler 60 and the needle valve 35 becomes too large, the amount of fuel leaking from the clearance increases, the flow velocity of the swirling flow of the fuel flowing into the swirl chamber 62 decreases, and the atomization performance is reduced. Decrease. According to the experimental results of the inventor, if this clearance is 30 μm or less,
It has been confirmed that the amount of fuel flowing through the clearance is small, and a decrease in the flow velocity of the swirling flow in the swirl chamber 62 can be suppressed.

The fuel injection valve of each embodiment described above is not limited to a system for directly injecting fuel into an engine cylinder, but can also be used for a system for injecting fuel into an intake manifold of each cylinder of an engine.

[0032]

As is apparent from the above description, according to the fuel injection valve of the first aspect of the present invention, the needle valve is slidably penetrated through the swirler that gives the swirling flow to the fuel. The pressure of the fuel swirl flow acting on the valve can be reduced, and the responsiveness of the opening operation (injection operation) of the needle valve can be improved. In addition, since the inlet of the injection hole is located at the center of the bottom surface of the fuel injection chamber and a flat portion is formed at the outlet side of the injection hole at a right angle to the injection hole, the turning energy of the fuel can be effectively atomized. It can be used to improve atomization performance. Further, when forming the injection hole at the lower end of the valve body, it is possible to perform the drilling process on the flat surface portion, so that the drilling process is facilitated and the processing accuracy can be improved.

[0033]

Furthermore , in the first aspect , the inlet-side end of the injection hole is rounded, so that the flow of fuel from the fuel injection chamber into the injection hole is smooth, and the loss of fuel swirling energy is reduced. can do. In addition, since the outlet-side edge of the injection hole has a right-angled edge, atomization can be promoted by the edge of the outlet-side edge of the injection hole, and wide-angle spraying can be performed.

According to the second aspect of the present invention , since a cylindrical sliding member formed as a separate component is fitted to the inner diameter portion of the swirler, a troublesome heat treatment for increasing or decreasing the surface hardness of the inner and outer diameters of the swirler. Becomes unnecessary, and workability can be further improved.

In the third aspect, the swirl flow is given to the fuel by the groove formed in the lower end surface of the swirler, so that the processing of the flow path (groove) for giving the swirl flow to the fuel becomes easy, and The fuel stagnation volume between the flow path (groove) and the injection hole can be reduced, and poor atomization at the beginning of injection can be reduced.

According to the fourth aspect , since the guide portion formed on the needle valve has a function of guiding the opening / closing stroke of the needle valve, fuel leakage does not occur in the clearance between the inner diameter portion of the swirler and the needle valve. As a result, the swirler can have a sufficient machining accuracy, and the workability can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a fuel injection valve showing a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of a lower portion of the fuel injection valve.

FIG. 3 is an enlarged longitudinal sectional view of a lower portion of a fuel injection valve showing a second embodiment of the present invention.

FIG. 4 is an enlarged longitudinal sectional view of a lower portion of a fuel injection valve showing a third embodiment of the present invention.

FIG. 5 is an enlarged vertical sectional view of a lower portion of a fuel injection valve showing a fourth embodiment of the present invention.

FIG. 6 is an enlarged vertical sectional view of a lower portion of a fuel injection valve according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view taken along the line AA in FIG. 6;

FIG. 8 is an enlarged vertical sectional view of a lower portion of a conventional fuel injection valve.

[Explanation of symbols]

23 ... solenoid coil, 26 ... fuel connector, 27 ...
Filter, 28 electric connector, 31 spring, 3
2 movable core, 34 valve body, 35 needle valve, 36 stopper, 37 swirler, 38 needle through hole, 39 fuel injection groove, 40 swirl chamber, 41
... swirl hole, 42 ... valve seat part, 43 ... fuel injection chamber, 44
... Injection hole, 45 ... Planar part, 50 ... Swirl, 51 ... Swirl hole, 52 ... Swirl chamber, 55,56 ... Swirl, 5
7, 58: sliding member, 60: swirler, 61: groove, 62
... Swirl room, 63 ... Guide part.

Continuation of front page (72) Inventor Yukio Sakamoto 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-7-1119584 (JP, A) JP-A-54-3615 (JP) , A) Minoru Sugita, "Making the Most of Machine Design Useful in the Workplace", 8th Edition, Nikkan Kogyo Shimbun, November 30, 1975, p. 143-145 (58) Field surveyed (Int. Cl. ⁷ , DB name) F02M 39/00-71/04

Claims (4)

(57) [Claims] A needle valve housed in a valve body to which fuel is supplied; and a needle through hole fitted in the valve body and through which the needle valve slidably penetrates. A swirler that gives a swirling flow to the flowing fuel, and a fuel injection chamber that is formed so as to introduce the swirling flow of the fuel downstream of the valve seat portion of the needle valve in the valve body and has a spherical concave bottom surface. An injection hole formed in the valve body so as to penetrate from the center of the bottom surface of the fuel injection chamber to the outside; and a flat portion formed at an outlet side of the injection hole in the valve body at right angles to the injection hole. A fuel injection valve comprising: an inlet-side edge of the injection hole is rounded; and an outlet-side edge of the injection hole has a right-angled edge. 2. A needle valve housed in a valve body to which fuel is supplied, and a needle through-hole fitted in the valve body and through which the needle valve slidably penetrates. A swirler that gives a swirling flow to the flowing fuel, and a fuel injection chamber that is formed so as to introduce the swirling flow of the fuel downstream of the valve seat portion of the needle valve in the valve body and has a spherical concave bottom surface. An injection hole formed in the valve body so as to penetrate from the center of the bottom surface of the fuel injection chamber to the outside; and a flat portion formed at an outlet side of the injection hole in the valve body at right angles to the injection hole. A fuel injection valve, characterized in that a cylindrical sliding member forming the needle through hole is fitted to an inner diameter portion of the swirler. 3. The swirler is configured such that a lower end surface of the swirler and a lower inner surface of the valve body are in close contact with each other in the vicinity of a valve seat of the needle valve. the fuel injection valve according to claim 1 or 2 flow paths is characterized by being composed give. 4. A needle valve housed in a valve body to which fuel is supplied, and a needle through hole which is fitted into the valve body and through which the needle valve slidably penetrates. A swirler that gives a swirling flow to the flowing fuel, and a fuel injection chamber that is formed so as to introduce the swirling flow of the fuel downstream of the valve seat portion of the needle valve in the valve body and has a spherical concave bottom surface. An injection hole formed in the valve body so as to penetrate from the center of the bottom surface of the fuel injection chamber to the outside; and a flat portion formed at an outlet side of the injection hole in the valve body at right angles to the injection hole. The needle valve is provided with a guide portion slidably fitted to an inner peripheral surface of the valve body near an upstream side of the swirler. Fuel injection valve which is characterized.