JPH11247738A - Fuel injector - Google Patents

Abstract

[PROBLEMS] To promote atomization of fuel, increase atomization and mixing property of injected fuel, and improve combustion efficiency of air-fuel mixture. SOLUTION: An injection nozzle 21 is constituted by a nozzle body 22 composed of a cylindrical portion 22A and a bottom portion 22B, and an injection port tube 23 fixed to the center side of the bottom portion 22B. Also,
On the bottom portion 22B side of the nozzle body 22, there is formed an inclined surface portion 22D tapered in diameter from the valve seat 22E side toward the flat surface portion side of the injection nozzle tube 23. On the distal end side of the needle valve 24, there is provided a truncated conical portion 24C tapering from the position of the seal portion 24B at a larger angle than the inclined surface portion 22D. A mixing floor 25 is formed between the truncated conical portion 24C, the inclined surface portion 22D, and the flat surface portion 23B to promote atomization of fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injector suitably used for a fuel injection device for an automobile engine, for example.

[0002]

2. Description of the Related Art A conventional fuel injector used for an automobile engine or the like will be described with reference to FIGS.

In FIG. 1, reference numeral 1 denotes an injector main body. The injector main body 1 is formed of a magnetic material such as electromagnetic stainless steel, and has a large-diameter cylinder 1A and a small-diameter cylinder provided at the tip end of the large-diameter cylinder 1A. 1B.

Reference numeral 2 denotes an injection nozzle whose base end is fixed in a small-diameter cylindrical portion 1B of the injector main body 1. The injection nozzle 2 is formed of a magnetic material such as electromagnetic stainless steel into a bottomed cylindrical shape, and has a cylindrical portion 2A. Has a bottom portion 2B and projects axially from the small-diameter cylindrical portion 1B of the injector body 1.
Further, an injection port 2C is formed in the bottom 2B of the injection nozzle 2, and the injection port 2C is configured to inject the fuel in the injector body 1 to the outside.

A needle valve 3 is provided in the injection nozzle 2 for opening and closing the injection port 2C. The needle valve 3 is slidable in the cylindrical portion 2A of the injection nozzle 2. The valve shaft 3A includes a fitted valve shaft 3A, a substantially conical valve portion 3B formed on the distal end side of the valve shaft 3A, and a flange-shaped stopper portion 3C provided at an axially intermediate portion of the valve shaft 3A. ing.

Reference numeral 4 denotes a fuel passage formed between the valve shaft 3A of the needle valve 3 and the injection nozzle 2. The fuel passage 4 is formed as an annular passage extending around the valve shaft 3A in the axial direction.
The fuel in the injector body 1 is guided to the injection port 2C.

Reference numeral 5 denotes an anchor formed of a magnetic material or the like into a closed cylindrical shape. The anchor 5 is fitted to the base end side of the needle valve 3 and displaces inside the injector body 1 integrally with the needle valve 3. It is. Note that a fuel passage (not shown) is also formed in the axial direction on the outer peripheral side of the anchor 5.

Reference numeral 6 denotes a stopper plate having a substantially U-shaped or C-shaped planar shape. The stopper plate 6 is used together with the injection nozzle 2 and the injector body 1 to determine the valve opening position (lift amount) of the needle valve 3. Is caulked and fixed in the small-diameter cylindrical portion 1B.

Reference numeral 7 denotes an electromagnetic actuator as an actuator provided in the injector body 1 for driving the needle valve 3. The electromagnetic actuator 7 is formed in a stepped cylindrical shape from a magnetic material such as an electromagnetic stainless steel. It comprises a core member 8 caulked and fixed to the large-diameter cylindrical portion 1A side of the injector main body 1, and an electromagnetic coil 9 provided between the core member 8 and the large-diameter cylindrical portion 1A of the injector main body 1. .

The core member 8 has an upper end projecting from the injector body 1 and a lower end facing the anchor 5 with a certain gap. The electromagnetic actuator 7 has a connector 10 for externally supplying power to the electromagnetic coil 9.
Is provided.

Reference numeral 11 denotes a valve spring that constantly urges the needle valve 3 in the valve closing direction. The valve spring 11 is disposed between the pipe member 12 fitted in the core member 8 and the anchor 5, The needle valve 3 is urged together with the anchor 5 toward the bottom 2 </ b> B of the injection nozzle 2.

Reference numeral 13 denotes a fuel hose connected to the upper end side of the core member 8. The fuel hose 13 supplies fuel discharged from a fuel pump (not shown) into the injector body 1.

The fuel injector according to the prior art has the above-described configuration. The fuel discharged from the fuel pump is supplied into the injector body 1 through the fuel hose 13 and the like, and the fuel passage 4 in the injection nozzle 2 is provided. Is also supplied.

In this state, the electromagnetic actuator 7
When power is supplied from the outside to the electromagnetic coil 9 via the connector 10, the core member 8 magnetically attracts the anchor 5 at the tip (lower end) side, and the needle valve 3 and the anchor 5 together with the valve spring 1
The sliding displacement is made upward against 1. As a result, the needle valve 3 opens as shown in FIG. 9 and fuel is injected outward from the injection port 2C.

[0015]

In the above-mentioned prior art, the valve portion 3B of the needle valve 3 is merely separated from the bottom portion 2B of the injection nozzle 2 and fuel is injected from the injection port 2C. As shown by the arrow in FIG. 9, the collision angle of the fuel near the injection port 2C is shallow,
Atomization of the fuel injected from the fuel cannot be promoted.

For this reason, in the prior art, it is difficult to mix the injected fuel with the intake air in an atomized state, and the mixing property between the fuel and the intake air cannot always be sufficiently increased. There is a problem that efficiency cannot be improved.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention can promote atomization of fuel, increase atomization and mixing property of injected fuel, and improve combustion efficiency of air-fuel mixture. It is an object of the present invention to provide a fuel injector capable of improving the fuel injection.

[0018]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an injector body, an injection nozzle provided in the injector body and having an injection port on a tip end side,
A fuel comprising a valve body slidably inserted into the injection nozzle and injecting fuel from the injection port of the injection nozzle when the valve is opened, and an actuator provided in the injector body for driving the valve body. Applies to injectors.

The first aspect of the present invention is characterized in that the injection nozzle is provided with a bottomed cylindrical nozzle body in which the valve body is slidably fitted, and a center of the bottom of the nozzle body. And an inner peripheral side provided with an injection port cylinder on the inner peripheral side serving as the injection port. Between the injection port cylinder and the valve element, fuel collides near the injection port to promote atomization of the fuel. That is, the atomization promoting space is formed.

With this configuration, the fuel flowing from the inside of the injector body toward the bottom side of the nozzle body when the valve body is opened is mutually separated in the atomization promoting space between the injection port cylinder and the valve body. The collision occurs almost directly in the radial direction, and the collision force at this time can promote the atomization of the fuel.

According to the second aspect of the present invention, an inclined surface portion is provided on the bottom side of the nozzle body to taper in diameter from the valve seat side where the valve body is detached and seated toward the injection port cylinder side. The diameter is reduced at an angle larger than that of the inclined surface portion, and a reduced diameter portion that forms a fine atomization promoting space between the inclined surface portion and the end surface of the nozzle tube is provided.

Since the diameter of the reduced diameter portion of the valve body is reduced at a large angle, the collision angle of the fuel in the atomization promoting space can be increased (deeper), and the fuel can be atomized. be able to.

Further, according to the third aspect of the present invention, a flat surface portion is formed in the reduced diameter portion of the valve body on the end face side facing the injection nozzle tube. This allows the fuel flowing into the atomization promoting space to collide almost directly from the front along the flat surface at a collision angle close to 180 degrees.

According to the fourth aspect of the present invention, a chamfered portion is formed on the end face of the nozzle cylinder facing the valve body between the nozzle and the nozzle. Thereby, the fuel which has collided with each other in the atomization promoting space and is atomized can be smoothly guided into the injection port, and the fuel spray can be stabilized.

On the other hand, a feature of the structure adopted by the invention of claim 5 is that the injection nozzle is provided with an inclined surface portion tapering from the valve seat side where the valve element is detached and seated toward the periphery of the injection port,
The valve body is provided with a reduced diameter portion that reduces the diameter at an angle larger than the inclined surface portion, and between the reduced diameter portion of the valve body and the periphery of the injection nozzle of the injection nozzle, fuel is supplied in the vicinity of the injection hole. That is, an atomization promoting space for promoting atomization of the fuel by collision is formed.

With this configuration, the fuel flowing from the inside of the injector body toward the injection port side of the injection nozzle when the valve body is opened can enter the atomization promoting space along the reduced diameter portion of the valve body. As a result, they collide with each other almost directly in the radial direction in the atomization promoting space, and the collision force at this time can promote the atomization of the fuel.

According to the sixth aspect of the present invention, the reduced diameter portion of the valve body has a flat surface portion on the end face side facing the injection port. This allows the fuel flowing into the atomization promoting space to collide almost directly from the front at a collision angle close to 180 degrees along the flat surface of the valve body.

Further, in the invention according to claim 7, a flat surface portion is formed around the injection port at a position facing the reduced diameter portion of the valve body. As a result, the fuel flowing into the atomization promoting space can collide almost directly from the front at an impact angle close to 180 degrees along the flat surface around the injection port.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fuel injector according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the embodiment, the same components as those of the above-described conventional technology are denoted by the same reference numerals, and description thereof will be omitted.

FIGS. 1 and 2 show a fuel injector according to a first embodiment of the present invention.
In the figure, reference numeral 21 denotes an injection nozzle employed in the present embodiment. The injection nozzle 21 has a nozzle body 22 and an injection port cylinder 23 described later.
It is composed of

Reference numeral 22 denotes a nozzle body constituting a main part of the injection nozzle 21. The nozzle body 22 is formed in a cylindrical shape with a bottom almost in the same manner as the injection nozzle 2 described in the prior art.
The distal end side of the cylindrical portion 22A serves as a bottom portion 22B and protrudes from the injector body 1 in the axial direction. However, as shown in FIG. 2, the nozzle body 22 is provided with an axial mounting hole 22C at the center side of the bottom portion 22B, and a nozzle 23 is fixed in the mounting hole 22C.

On the inner surface (upper surface) side of the bottom portion 22B,
As shown in FIG. 2, an inclined surface portion 22D is formed to taper toward the opening end side of the mounting hole 22C at an inclination angle of .theta.1, and the large-diameter (upper) side of the inclined surface portion 22D will be described later. A valve seat 22E for the needle valve 24 is provided.

Reference numeral 23 denotes a nozzle tube provided in the mounting hole 22C of the nozzle body 22. The nozzle tube 23 is formed in a short tube shape of a metal material or the like, and its outer peripheral side is formed by means such as laser welding or press fitting. And is fixed in the mounting hole 22C. The inner peripheral side of the nozzle cylinder 23 is an injection port 23A that connects the inside and the outside of the nozzle body 22, and the fuel in the nozzle body 22 is injected from the injection port 23A toward a combustion chamber (not shown) of the engine. Is done.

Further, the end face of the nozzle tube 23 is provided with a nozzle 23A.
Is formed as a flat surface portion 23B perpendicular to the axis of the nozzle body 22. The flat surface portion 23B forms a mixing floor 25 to be described later with the tip end side of the needle valve 24 together with the inclined surface portion 22D of the nozzle body 22. .

Numeral 24 designates a needle valve as a valve body slidably inserted into the nozzle body 22. Although the needle valve 24 is configured substantially similarly to the needle valve 3 described in the prior art, In the needle valve 24, a seal portion 24B as a valve portion and a truncated conical portion 24C as a reduced diameter portion are formed on the distal end side of the valve shaft 24A.

Here, the seal portion 24B of the needle valve 24
Is formed as a tapered surface extending in a belt shape over the entire circumference by reducing the diameter from the tip of the valve shaft 24A at an angle corresponding to the inclined surface portion 22D of the nozzle body 22.
It is configured to take off and sit on E.

As shown by the following equation (1), the truncated conical portion 24C is tapered from the minimum diameter end (lower end) of the seal portion 24B to an angle θ2 larger than the angle θ1 of the inclined surface portion 22D. Have been.

[0038]

[Equation 1] θ2> θ1

The top side of the truncated conical portion 24C becomes a circular flat surface portion 24D, and the outer diameter of the flat surface portion 24D is set to, for example, 0.2 mm or more.

Reference numeral 25 denotes the inclined surface portion 22 of the nozzle body 22.
D, a mixing floor formed between the flat surface portion 23B of the nozzle tube 23 and the truncated conical portion 24C of the needle valve 24, and the mixing floor 25 defines an atomization promoting space near the injection port 23A where fuel collides. Make up. The mixing floor 25 transfers the fuel flowing between the seal portion 24B and the valve seat 22E to the injection port 23A when the needle valve 24 is opened, as indicated by arrows F and F in FIG. And the fuel is atomized by the collision force at this time, and the fuel is injected from the injection port 23A to the outside of the injection nozzle 21.

The fuel injector according to the present embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.

According to the present embodiment, however, the injection nozzle 21 is constituted by the nozzle body 22 and the injection port cylinder 23,
On the bottom portion 22B side of the nozzle body 22, there is formed an inclined surface portion 22D tapered at an inclination angle of θ1 from the valve seat 22E side to the flat surface portion 23B side of the nozzle tube 23, and the tip of the needle valve 24. On the side, the seal portion 24B
Is provided with a frusto-conical portion 24C tapering at an angle .theta.2 larger than the angle .theta.1 of the inclined surface portion 22D, whereby the truncated conical portion 24C and the inclined surface portion 22D and the flat surface portion 23B are provided. Has a configuration in which the mixing floor 25 is formed, the following operational effects can be obtained.

That is, when the seal portion 24B is separated from the valve seat 22E by the valve-opening operation of the needle valve 24, the fuel from the injector body 1 side causes the seal portion 24B and the valve seat 22
When passing between E and E, a throttle action is applied to the fuel between the two, and the fuel can be circulated toward the injection port 23A with the flow velocity increased. The fuel in the high-speed state is guided by the frusto-conical portion 24C having a large taper angle so as to flow in a radially inward direction, and flows near the horizontal direction in the mixing floor 25, as shown in FIG. They collide with each other in the directions indicated by arrows F and F.

As a result, in the mixing floor 25, the fuel can collide almost directly from the front at an angle close to horizontal (180 degrees), and the collision angle can be made large (deep). Atomization of fuel can be promoted. Then, by injecting the fuel atomized in the mixing floor 25 from the injection port 23A to the outside, the intake air can be satisfactorily mixed with the atomization of the fuel promoted. In addition, when fuel passes through the injection port 23A of the injection port cylinder 23, the spray of the fuel can be stabilized.

Therefore, according to the present embodiment, the atomization of the fuel can be reliably promoted by the mixing floor 25 formed between the bottom side of the injection nozzle 21 and the tip of the needle valve 24, and the fuel is injected from the injection port 23A. It is possible to improve the atomization and mixing property of the fuel to be used, and it is possible to surely improve the combustion efficiency of the air-fuel mixture.

Next, FIG. 3 shows a second embodiment of the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. It shall be. However, a feature of the present embodiment is that the nozzle cylinder 3 having the nozzle 31 </ b> A in the mounting hole 22 </ b> C of the nozzle body 22.
1 is fixed, and a chamfered portion 31C having a convex curved shape is formed between the end surface 31B of the injection port tube 31 and the injection port 31A located on the mixing floor 25 side.

Thus, in the present embodiment configured as described above, substantially the same operation and effect as those of the first embodiment can be obtained. However, in the present embodiment, in particular, the atomization in the mixing floor 25 is performed. Of fuel promoted by chamfer 3
The fuel can be smoothly guided into the injection port 31A along 1C, and the fuel spray can be further stabilized.

Further, it is possible to prevent the fuel from staying on the end surface 31B side of the injection nozzle tube 31 by the chamfered portion 31C, and it is possible to solve the problem that non-volatile components and the like in the fuel adhere to the end surface 31B side.

Next, FIG. 4 shows a third embodiment of the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. It shall be. However, the feature of the present embodiment is that the nozzle cylinder 4 having the nozzle 41A in the mounting hole 22C of the nozzle body 22 is provided.
1 is fixed, and a chamfered portion 41B that is inclined obliquely downward toward the injection port 41A is formed on the end face side of the injection port tube 41 located on the mixing floor 25 side.

Thus, in the present embodiment configured as described above, substantially the same operation and effect as those of the first embodiment can be obtained. However, in the present embodiment, in particular, the atomization in the mixing floor 25 is performed. The fuel promoted by the chamfer 4
1B leads to the injection port 41A side, so that the spraying of the fuel can be further stabilized, and the chamfered portion 41B can prevent the stagnation of the fuel, and can solve the problems such as the attachment of the non-volatile components and the like.

Next, FIG. 5 shows a fourth embodiment of the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. It shall be. However, the features of the present embodiment are that the needle valve 51 as the valve body is provided with the valve shaft 51A and the seal portion 5 as the valve portion.
1B and a conical portion 51C as a reduced diameter portion.

Here, although the needle valve 51 has substantially the same structure as the needle valve 24 described in the first embodiment, the needle valve 51 has a conical shape as shown by the following equation (2). The diameter of the portion 51C is reduced at a larger angle θ3.

[0053]

[Equation 2] θ3> θ2> θ1

The tip of the conical portion 51C is formed as a corner portion 51D, and the apex angle of the corner portion 51D is twice (2 × θ) the angle θ3.
3), for example, an obtuse angle of about 130 to 160 degrees. The conical portion 51C of the needle valve 51 forms a mixing floor 52 as an atomization promoting space between the conical portion 51C and the flat surface portion 23B of the nozzle tube 23.

Thus, in the present embodiment configured as described above, substantially the same operation and effect as those of the first embodiment can be obtained. However, in the present embodiment, in particular, the atomization in the mixing floor 52 is performed. The fuel promoted by the conical portion 51
The corner portion 51D of C can guide the fuel toward the injection port 23A satisfactorily, and the fuel spray at the injection port 23A can be stabilized.

Next, FIG. 6 shows a fifth embodiment of the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. It shall be. However, the feature of this embodiment is that the injection nozzle 6
1 is formed of a single material as a bottomed cylindrical body, and for example, the nozzle body 22 and the nozzle barrel 2 used in the first embodiment are formed.
3 is formed as an integral body.

Here, the injection nozzle 61 has substantially the same configuration as the injection nozzle 2 described in the related art, and has a cylindrical portion 61A, a bottom portion 61B, and an injection port 61C. The peripheral portion (periphery) of the injection port 61C facing the truncated cone portion 24C of the needle valve 24 is formed as an annular flat surface portion 61D.

Also, on the inner surface (upper surface) side of the bottom portion 61B, an inclined surface portion 6 whose diameter is reduced in a tapered shape toward the flat surface portion 61D side.
1E, and a large diameter (upper) side of the inclined surface portion 61E is a valve seat 6 on which the seal portion 24B of the needle valve 24 is detached and seated.
1F. A mixing floor 62 is formed between the truncated conical portion 24C of the needle valve 24, the flat surface portion 61D, and the inclined surface portion 61E as an atomization promoting space.

Thus, in the present embodiment having the above-described structure, substantially the same operation and effect as those of the first embodiment can be obtained. Is formed of a single material, the number of parts can be reduced, and workability during assembly can be improved.

Next, FIG. 7 shows a sixth embodiment of the present invention. In this embodiment, the same components as those in the fifth embodiment are denoted by the same reference numerals, and the description thereof is omitted. It shall be. However, the features of the present embodiment are that the needle valve 71 as a valve body is provided with a valve shaft 71A and the seal portion 7 as a valve portion.
1B and a conical portion 71C as a reduced diameter portion.

Here, although the needle valve 71 has substantially the same configuration as the needle valve 24 described in the first embodiment, the needle valve 71 has a conical portion 71C whose diameter is reduced by a larger angle. The tip is for example 130-16
It is formed as a corner 71D having an obtuse angle of about 0 degrees. The conical portion 71C of the needle valve 71 forms a mixing floor 72 as an atomization promoting space between the conical portion 71C and the flat surface portion 61D of the injection nozzle 61.

Thus, in this embodiment having the above-described structure, substantially the same operation and effect as those of the fifth embodiment can be obtained. In this embodiment, however, the atomization in the mixing floor 72 is particularly performed. The fuel promoted by the conical portion 71
The corner 71D of C can guide the fuel toward the injection port 61C satisfactorily, and the fuel spray at the injection port 61C can be stabilized.

In the fifth and sixth embodiments,
Although it has been described that the annular flat surface portion 61D is formed around the injection port 61C on the bottom portion 61B side of the injection nozzle 61, the present invention is not limited to this, and for example, in the second and third embodiments, The chamfered part 31C of the used nozzle cylinder 31 (41)
The same processing as (41B) may be performed.

Further, in the first to fourth embodiments, the nozzle cylinder 23 (31, 41) is connected to the mounting hole 2 of the nozzle body 22.
Although it has been described that the nozzle tube 23 (31, 41) is fixed in the mounting hole 22C in this case, it is not always necessary to fit the nozzle tube 23 (31, 41) in the mounting hole 22C. The nozzle body 22 may be configured to protrude outward from the bottom portion 22B, and the fuel spray pattern may be adjusted based on the protruding length.

[0065]

As described in detail above, according to the first aspect of the present invention, the injection nozzle is constituted by a nozzle body having a bottomed cylindrical shape and an injection hole tube whose inner peripheral side is the injection hole. Since the atomization promoting space that promotes atomization of fuel is formed between the injection port cylinder and the valve body, the fuel flowing from the inside of the injector body toward the bottom side of the nozzle body when the valve body is opened is opened. In the atomization promoting space between the injection port cylinder and the valve element, it is possible to collide with each other almost directly from the radial direction from the radial direction, and the collision force at this time can promote the atomization of the fuel and the fuel injected from the injection port. Therefore, it is possible to improve the atomization and mixing property of the fuel, and to surely improve the combustion efficiency of the air-fuel mixture.

According to the second aspect of the present invention, an inclined surface portion is provided on the bottom side of the nozzle body to taper in diameter from the valve seat side where the valve body is detached and seated toward the injection port cylinder side. Is configured to reduce the diameter at an angle larger than the inclined surface portion and to provide a reduced-diameter portion that forms an atomization-promoting space between the end surface of the nozzle cylinder and the diameter-reducing portion of the valve body. The collision angle of the fuel inside can be made deep, and the atomization of the fuel can be surely promoted.

Further, according to the third aspect of the present invention, since the flat portion is formed on the end face side of the valve body facing the injection port cylinder, the fuel flowing into the atomization promoting space is formed on the flat surface portion. At a collision angle close to 180 degrees along the line, and the fuel can be further atomized.

According to the fourth aspect of the present invention, since the chamfered portion is formed between the valve body and the injection port at the end face of the nozzle port cylinder, the collision occurs with each other in the atomization promoting space and the atomization is performed. The chamfered portion can smoothly guide the fuel to the inside of the injection port, and the fuel spray can be stabilized.

On the other hand, according to the fifth aspect of the present invention, since the atomization promoting space for promoting atomization of fuel is formed between the reduced diameter portion of the valve element and the periphery of the injection nozzle of the injection nozzle, the valve element is formed. When the valve is opened, the fuel flowing from the inside of the injector body toward the injection port side of the injection nozzle can be guided into the atomization promoting space along the reduced diameter portion of the valve element, and the fuel flows in the atomization promoting space. Colliding from almost directly, and the collision force at this time can promote the atomization of fuel and improve the atomization and mixing properties of the fuel injected from the injection port, thereby reliably improving the combustion efficiency of the air-fuel mixture it can.

According to the sixth aspect of the present invention, since the flat portion is formed in the reduced diameter portion of the valve body on the end face side opposite to the injection port, the fuel flowing into the atomization promoting space is prevented by the valve. The collision can be made almost directly from the front at a collision angle close to 180 degrees along the flat surface of the body, and the atomization of the fuel can be surely promoted.

Further, since the flat surface portion is formed around the injection port at a position facing the reduced diameter portion of the valve body, the fuel flowing into the atomization promoting space can be prevented. A collision can be made almost directly from the front along a flat surface around the injection port at a collision angle close to 180 degrees, which can also promote atomization of fuel.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view showing an injection nozzle and a distal end side of a needle valve of a fuel injector according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part in FIG.

FIG. 3 is an enlarged longitudinal sectional view showing a main part of an injection nozzle and a needle valve of a fuel injector according to a second embodiment.

FIG. 4 is an enlarged longitudinal sectional view showing a main part of an injection nozzle and a needle valve of a fuel injector according to a third embodiment.

FIG. 5 is an enlarged longitudinal sectional view showing a main part of an injection nozzle and a needle valve of a fuel injector according to a fourth embodiment.

FIG. 6 is an enlarged longitudinal sectional view showing a main part of an injection nozzle and a needle valve of a fuel injector according to a fifth embodiment.

FIG. 7 is an enlarged longitudinal sectional view showing an essential part of an injection nozzle and a needle valve of a fuel injector according to a sixth embodiment.

FIG. 8 is a longitudinal sectional view showing a conventional fuel injector.

FIG. 9 is an enlarged sectional view of a main part showing an injection nozzle and a needle valve in FIG. 8;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Injector main body 7 Electromagnetic actuator (actuator) 21, 61 Injection nozzle 22 Nozzle body 22A, 61A Tube part 22B, 61B Bottom part 22C Mounting hole 22D, 61E Inclined surface part 22E, 61F Valve seat 23, 31, 41 Injection nozzle tube 23A, 31A, 41A, 61C Injection port 23B, 61D Flat surface part 24, 51, 71 Needle valve (valve element) 24A, 51A, 71A Valve shaft 24B, 51B, 71B Seal part (valve part) 24C Truncated conical part (reduced diameter part) 24D Flat surface portion 25, 52, 62, 72 Mixing floor (fine atomization promoting space) 31C, 41B Chamfered portion 51C, 71C Conical portion (reduced diameter portion)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 61/18 350 F02M 61/18 350D

Claims (7)

[Claims] 1. An injector body, an injection nozzle provided on the injector body and having an injection port on a tip end side, and slidably inserted into the injection nozzle to supply fuel from the injection port of the injection nozzle when the valve is opened. In a fuel injector including a valve element to be injected and an actuator provided in the injector body for driving the valve element, the injection nozzle has a bottomed cylindrical shape into which the valve element is slidably inserted. Nozzle body, and a nozzle body provided at the center of the bottom of the nozzle body and having an inner peripheral side serving as the injection port. A fuel injector characterized in that a fuel atomization promoting space is formed by colliding fuel to promote atomization of the fuel. 2. An inclined surface portion which is tapered from the valve seat side on which the valve body is detached and seated toward the injection port cylinder side is provided on the bottom side of the nozzle body, and the inclined surface portion is provided on the valve body. 2. The fuel injector according to claim 1, further comprising a reduced diameter portion that reduces the diameter at an angle larger than the angle and forms the atomization promoting space between the nozzle and the end face of the nozzle nozzle. 3. 3. The fuel injector according to claim 2, wherein a flat surface portion is formed in the reduced diameter portion of the valve body on an end face side facing the nozzle cylinder. 4. The fuel injector according to claim 1, wherein a chamfered portion is formed between an end face of the injection port cylinder facing the valve element and the injection port. 5. An injector body, an injection nozzle provided on the injector body and having an injection port on a tip end side, and slidably inserted into the injection nozzle to supply fuel from the injection port of the injection nozzle when the valve is opened. In a fuel injector including a valve element to be injected and an actuator provided in the injector body to drive the valve element, the injection nozzle is provided around the injection port from a valve seat side where the valve element is detached and seated. The valve body is provided with an inclined surface portion that reduces its diameter in a tapered shape, and the valve body is provided with a reduced diameter portion that reduces the diameter at an angle larger than the inclined surface portion. A fuel atomizing space formed between the fuel injector and the fuel injector in the vicinity of the injection port to promote atomization of the fuel. 6. The fuel injector according to claim 5, wherein a flat surface portion is formed in an end face side of the valve body facing the injection port in the reduced diameter portion. 7. A flat surface portion is formed around the injection port at a position facing the reduced diameter portion of the valve body.
7. The fuel injector according to 3, 5, or 6.