JP2004003518A - Fuel injection nozzle and fuel supply equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection nozzle for atomizing fluid by a simple constitution. <P>SOLUTION: A tip-end surface 86a of a needle valve 86 is formed in a convex spherical shape protruding downstream of the fuel in the internal peripheral side of a contact part 86b. An orifice plate 87 is formed e.g. by pressing a platy material with a punch having a spherical tip end in which an orifice 88 is formed beforehand. An opposing face 87a of the orifice plate 87 is formed in conformity with the shape of the tip-end surface 86a so as to have almost the same space between the opposing surface 87a and the tip-end surface 86a. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a fuel injection nozzle and a fuel supply device, and more particularly to an injection nozzle portion of a fuel injection valve that injects and supplies fuel to an internal combustion engine (hereinafter, referred to as an engine) for a vehicle. is there.

In such a fuel injection valve, from the viewpoints of reducing fuel consumption, improving exhaust emissions, and stabilizing the operability of the engine, etc., "atomization of fuel" injected from the injection hole is one of the important factors. is there. As a method of promoting the atomization of the injected fuel, there are auxiliary atomizing means by collision of air with the injected fuel, heating near the injection hole, etc., but all these atomizing means are expensive. There is a problem.

On the other hand, a fuel injection valve disclosed in Patent Literature 1 is known as an example in which an orifice plate having an orifice formed at a tip portion of the fuel injection valve is provided to promote atomization. In this fuel injection valve, a configuration in which a concave portion is formed at the distal end of the needle valve and a configuration in which the distal end of the needle is formed flat at right angles to the needle axis direction are disclosed.
U.S. Pat. No. 5,383,607

However, in the above-described configuration in which the concave portion is formed at the tip of the needle, the fuel flows or swirls in the direction opposite to the injection direction along the concave portion of the needle tip until the fuel reaches the orifice, and the fuel does not flow smoothly. However, the internal energy of the fuel was lost, and sufficient atomization could not be obtained.

In the configuration in which the needle tip is formed flat at right angles to the needle axis direction, the orifice plate is recessed with respect to the needle valve, so that the fuel spreads axially between the needle tip face and the orifice plate. , The internal energy was lost, and sufficient atomization could not be obtained.

An object of the present invention is to provide a fuel injection nozzle that atomizes a fluid with a simple configuration, focusing on a phenomenon in which turbulence due to collision of a fluid flow greatly affects atomization.
It is another object of the present invention to provide a fuel injection nozzle that suppresses atomized fluid spray from overlapping at an injection destination.

According to the first to eighth aspects of the present invention, a substantially disk is formed by the surface of the orifice plate facing the valve member, the distal end surface formed on the inner peripheral side of the contact portion at the downstream distal end portion of the valve member, and the inner wall surface. Is formed in a convex spherical shape or a convex conical shape protruding toward the fuel downstream side on the inner peripheral side of the contact portion, and the orifice plate is recessed toward the fuel downstream side. It is characterized by having.

This allows the fluid chamber to be flattened, creates a flow along the opposing surface of the orifice plate, and induces the fluid flows to collide with each other.

Therefore, the fluid ejected from the orifice plate is atomized due to the turbulence due to the collision, and the fluid is sprayed with directionality.

According to the second aspect of the present invention, since the orifices are arranged on double concentric circles, it is possible to prevent the atomized spray injected from each orifice from overlapping at the injection destination. In addition, the atomized spray can be uniformly supplied.

According to the third aspect of the present invention, the inclination angle of the outer peripheral orifice is larger than the inclination angle of the inner peripheral orifice. Overlapping with the spray injected from the orifice can be prevented. Therefore, the atomized spray can be supplied uniformly.

Further, in the invention according to claim 4, since the orifice is formed inside a virtual envelope connecting a position where the direction of the main fluid flow downstream of the contact portion intersects with the facing surface, The main fluid can be prevented from being directly injected from the orifice without colliding with the orifice plate.

Therefore, the main flow of the fluid colliding with the orifice plate changes its direction along the orifice plate and collides with another fluid flow. Fluid ejected from the orifice is atomized due to turbulence due to collision, and becomes a directional spray.
In the invention according to claim 5, there is a relation of 0.5 <t / d <1.0 between the plate thickness t of the orifice plate and the diameter d of the orifice. If 0.5 ≧ t / d, the directionality of the fluid spray injected from the orifice is not stable. When t / d ≧ 1.0, the atomized spray is reattached while passing through the orifice, and the fluid spray cannot be sufficiently atomized.

{That is, by maintaining the relationship of 0.5 <t / d <1.0, the fluid can be ejected in a predetermined direction, and the fluid spray can be sufficiently atomized.

According to the sixth aspect of the present invention, by setting a small orifice diameter, a large number of orifices are provided and a predetermined injection amount is injected, so that the area where the fluid injected from the orifice comes into contact with air is reduced. Increasing the number can promote more atomization.

According to the seventh aspect of the invention, the spray angle of the fluid ejected from the orifice can be increased, so that the fluid can be ejected over a wide range.

According to an eighth aspect of the present invention, the orifice is inclined with respect to the central axis of the valve member in a direction away from the central axis.

(4) Since the spray angle of the fluid ejected from the orifice can be increased, the fluid can be ejected over a wide range.

流体 Furthermore, by indenting the orifice plate, a fluid ejection nozzle requiring a large ejection angle can be easily manufactured.

According to the ninth aspect of the present invention, the fuel injection device having one of the fuel injection nozzles according to any one of the first to eighth aspects is connected to the downstream side of the throttle valve and the upstream of the junction of the intake distribution pipes connected to each cylinder. , The fuel spray can be uniformly supplied to each cylinder by one fuel injection device. Therefore, it is particularly suitable for mounting on a small engine.

Hereinafter, embodiments and reference examples of the present invention will be described with reference to the drawings.

(First reference example)
As a first reference example of the present invention, FIGS. 1, 2 and 3 show a fuel injection nozzle applied to a fuel injection valve of a fuel supply device for a gasoline engine.

As shown in FIG. 3, a fixed core 21 made of a ferromagnetic material is accommodated in a resin housing mold 11 of a fuel injection valve 10 as a fuel injection device. The movable core 22 made of a magnetic material is formed in a cylindrical shape, and is arranged in the internal space of the non-magnetic pipe 23 and the magnetic pipe 24. The outer diameter of the movable core 22 is set slightly smaller than the inner diameter of the nonmagnetic pipe 23, and the movable core 22 is slidably supported by the nonmagnetic pipe 23. The movable core 22 faces the fixed core 21 in the axial direction, and is disposed so as to form a predetermined gap with the lower end surface of the fixed core 21.

The non-magnetic pipe 23 is fitted around the outer periphery of the movable core side end of the fixed core 21 and fixed by laser welding or the like. A magnetic pipe 24 made of a magnetic material and formed in a stepped pipe shape is connected to an end of the non-magnetic pipe 23 opposite to the fixed core. The non-fixed core side of the non-magnetic pipe 23 forms a guide for the movable core 22. As shown in FIG. 1, a tip surface 25a on the fuel injection side of a needle valve 25 as a valve member is formed in a gentle conical convex shape whose diameter gradually decreases toward the fuel flow, and a contact portion 25b Can be annularly seated on the valve seat 31b provided on the valve body 30. At the other end of the needle valve 25, a joint 25d is formed as shown in FIG. Then, the joint 25d and the movable core 22 are laser-welded, and the needle valve 25 and the movable core 22 are integrally connected. A double chamfer as a fuel passage is provided on the outer periphery of the joint 25d.

The valve body 30 is inserted into the magnetic pipe 24 via the spacer 28 and is fixed to the magnetic pipe 24 by laser welding or the like. The thickness of the spacer 28 is adjusted so that the air gap between the fixed core 21 and the movable core 22 has a predetermined value.

The orifice plate 32 made of stainless steel is formed in a cup shape, and is joined to the tip of the valve body 30 on the fuel downstream side of the needle valve 25 by welding, for example, full circumference welding.

The sleeve 40 is made of resin, and is press-fitted to the outer periphery of the valve body 30 and the orifice plate 32 to protect the orifice plate 32. The fuel injected from the orifices 32 a and 32 b formed in the orifice plate 32 is injected into the engine from the opening 40 a of the sleeve 40.

一端 One end of the compression coil spring 26 contacts the spring seat 22a provided on the movable core 22, and the other end of the compression coil spring 26 contacts the bottom of the adjusting pipe 27. The compression coil spring 26 urges the movable core 22 and the needle valve 25 downward in FIG. 3, that is, in a direction in which the contact portion 25b is seated on the valve seat 31b of the valve body 30.

The adjusting pipe 27 is pressed into the inner periphery of the fixed core 21. By adjusting the press-fitting position of the adjusting pipe 27 at the time of assembly, the urging force of the compression coil spring 26 can be adjusted.

The electromagnetic coil 50 is wound around the outer periphery of a resin spool 51, and the spool 51 is provided around the fixed core 21, the non-magnetic pipe 23, and the magnetic pipe 24. A housing mold 11 is resin-molded around the outer periphery of the electromagnetic coil 50 and the spool 51, and the housing mold 11 surrounds the electromagnetic coil 50. When an exciting current flows from the terminal 52 to the electromagnetic coil 50 via a lead wire by an electronic control unit (not shown), the needle valve 25 and the movable core 22 are attracted toward the fixed core 21 against the urging force of the compression coil spring 26. Then, the contact portion 25b is separated from the valve seat 31b.

The terminal 52 is embedded in the housing mold 11 and is electrically connected to the electromagnetic coil 50. The terminal 52 is connected to an electronic control unit (not shown) via a wire harness.

The two metal plates 61 and 62 are provided such that one upper end is in contact with the outer periphery of the fixed core 21 and the other lower end is in contact with the outer periphery of the magnetic pipe 24. It is a member that forms a road. The electromagnetic coil 50 is protected by the two metal plates 61 and 62.

The filter 63 is disposed above the fixed core 21 and removes foreign matter such as dust in the fuel that is pumped from a fuel tank by a fuel pump or the like and flows into the fuel injection valve 10. The fuel that has flowed into the fixed core 21 through the filter 63 passes through the gap between the adjusting pipe 27 and the two chamfered portions formed at the joint 25 d of the needle valve 25, and further, slides between the valve body 30 and the needle valve 25. It passes through the gap between the four chamfered portions formed in the portion and reaches the valve portion formed by the contact portion 25b of the needle valve 25 and the valve seat 31b. As shown in FIG. 1, when the contact portion 25b separates from the valve seat 31b, fuel flows into the fuel chamber 35 from an opening formed by the contact portion 25b and the valve seat 31b.

燃料 The fuel chamber 35 as a fluid chamber is partitioned by the opposing surface 33 of the orifice plate 32, the conical slope 31a of the valve body 30, and the tip end surface 25a, and is formed in a substantially disk shape.

Hereinafter, the structures of the needle valve 25, the valve body 30, and the orifice plate 32 will be sequentially described in detail.

(1) Needle valve 25
As shown in FIG. 1, the distal end portion of the needle valve 25 includes a distal end surface 25a, a contact portion 25b, and an annular curved surface 25c connecting the distal end surface 25a and the contact portion 25b. The distal end surface 25a is formed on the inner peripheral side of the contact portion 25b, and the center is located on the axis of the needle valve 25. The axial distance h of the needle valve when the needle is opened between the distal end surface 25a and the opposing surface 33 of the orifice plate 32 and the diameter d of orifices 32a and 32b of the orifice plate 32, which will be described later, satisfy the following expression (1). It is set as follows.

h <l. 5d, d <0.3 (mm) (1)
In particular, it is preferable to increase the injection amount by providing a large number of orifices with small diameter orifices of d <0.25 or so. This is because by allowing a predetermined flow rate of fuel to pass through a large number of orifices, the area of the fuel injected from the orifices in contact with air is increased, and the atomization is further promoted.

Since the orifice diameter is small, it is easy to form a fuel passage between orifices in an orifice plate having a predetermined area. Therefore, as described later, the value of DS / DH can be set in a wide range when the seat diameter of the needle valve 25 is DS and the pitch between the orifices is DH. More preferably, d is about 0.15.

The distance h and the orifice diameter d are set so as to satisfy the expression (1). When the needle valve 25 is separated from the conical slope 31a of the valve body 30, the gap between the abutting portion 25b and the conical slope 31a is set to the orifice plate. This is because the fuel advances to the side 32 and hits the facing surface 33 of the orifice plate 32 to be bent toward the fuel chamber 35 to form a fuel flow along the facing surface 33. This fuel flow is divided into a flow directly toward the orifice and a flow passing between the orifices, and the flow passing between the orifices is U-turned toward the orifice by a flow facing the center of the orifice plate. The fuel flows heading toward the orifice from directions opposite to each other in the radial direction collide with each other immediately above the orifice, and form an unstable flow state to promote atomization of the fuel.

That is, since the distance h and the diameter d are set so as to satisfy the expression (1), the fuel can flow through the narrow gap between the front end surface 25a and the opposing surface 33, and the fuel flows along the opposing surface 33 Collision can be induced. This makes it possible to increase the energy of collision between the fuels and promote atomization of the fuel.

(2) Valve body 30
The inner diameter of the valve body 30 is reduced from the vicinity of the tip toward the orifice plate 32, and a conical slope 31a is formed on the inner wall surface 31 forming the fuel passage as a fluid passage on the orifice plate 32 side. The contact portion 25b of the needle valve 25 can be seated on a valve seat 31b formed on the conical slope 31a.

{The vertical distance H between the valve seat 31b and the facing surface 33 and the diameter d of the orifices 32a and 32b are set so as to satisfy the following expression (2).

H <4d (2)
That is, the valve seat 31 b, which is the fuel inlet to the fuel chamber 35, is set near the orifice plate 32.

The diameter of the conical slope 31a is reduced toward the fuel downstream side, and the vertical distance H between the valve seat 31b and the facing surface 33 and the diameter d of the orifices 32a and 32b are set so as to satisfy Expression (2). Accordingly, when the needle valve 25 and the valve body 30 are separated from each other, the fuel that flows into the fuel chamber 35 from the space between the abutment 25b and the valve seat 31b to heal to the conical slope 31a and to flow along the opposed surface 33. be able to.

(3) Orifice plate 32
As shown in FIG. 2A, a total of twelve orifices 32a and 32b having the same diameter d are formed through the orifice plate 32 in the thickness direction of the orifice plate 32 for controlling the flow direction of the spray. . As shown in FIG. 1, the orifices 32a and 32b are imaginary envelope lines connecting positions where the direction of the main fuel flow downstream of the contact portion 25b intersects with the facing surface 33. In FIG. Is formed inside the line of intersection.

As shown in FIG. 2A, the orifices 32a and 32b are arranged concentrically, and the orifice 32a is located on the inner peripheral side of the orifice 32b. Further, each orifice is arranged so that a circle can be secured in contact with each other at the same radius from the center of each orifice. Therefore, a region in which the sprays sprayed from the respective orifices are substantially equal can be secured, so that the sprays hardly overlap at the spray destination.

The orifices 32a and 32b are inclined away from the central axis toward the fuel downstream side of the orifice plate 32 as shown in FIGS. 2B and 2C, and the thickness direction of the orifice plate 32 is changed. When the inclination angles of the orifices 32a and 32b with respect to are θ1θ and θ2, θ1 and θ2 satisfy the following expression (3).

θ1 <θ2 (3)
Since the orifice 32b on the outer peripheral side has a larger inclination angle, if the inclination angles θ1 and θ2 are appropriately set, the sprays sprayed from the orifices 32a and 32b are uniformly atomized without overlapping each other.

す る と Also, if the number of orifices 32a is n1 and the number of orifices 32b is n2, then n1 = n2. If the distribution of the number of orifices is made equal as described above and the orifices 32a and 32b are arranged so that a circle can be secured in contact with the same radius from the center, a line-symmetric axis can be drawn without passing through each orifice. Can not. That is, according to the arrangement of the present embodiment, the spray is in one direction.

Assuming that the pitch between the orifices 32a and 32b is DH0 and DH1 and the seat diameter of the needle valve 25 is DS as shown in FIG. 1, DH0, DH1 and DS satisfy the following equation (4).

1.5 <DS / DH0 <6, 1.5 <DS / DH1 <6 (4)
Therefore, when the needle valve 25 and the valve body 30 are separated from each other, the fuel flowing into the fuel chamber 35 from between the contact portion 25b and the valve seat 31b flows along the conical slope 31a and then directly to the orifice. After the direction is changed by the opposing surface 33 of the orifice plate 32 without flowing, the air advances a predetermined distance between the opposing surface 33 and the flat surface 25a. Therefore, the fuel can be atomized efficiently without the main flow of the fuel flowing directly into the orifices 32a, 32b. Further, by satisfying the expression (4), the orifices 32a and 32b can be arranged in a range not too close to the center of the orifice plate 32 and not too wide on the outer peripheral side of the orifice plate 32. Therefore, the strength of the fuel flow flowing into each of the orifices 32a, 32b can be made substantially uniform regardless of the flow direction. As a result, the internal energy of the fuel can be efficiently used in the form of turbulence due to collision between flows, and extremely ideal atomization can be realized.

均一 Further, since a uniform collision can be obtained at the center of the inlet of the orifice, a spray having a very directivity can be obtained along the inclination of the entire periphery of the side wall forming the orifice.

FIG. 4 is a graph in which the respective values of DS / DH, 1.5 d-h, and 4 d-H are plotted on the horizontal axis, and the degree of atomization is plotted on the vertical axis. The orifice diameter d is 0.15 mm. The measurement results of (A), (B), and (C) in FIG. 4 are obtained by varying two parameters within a range that satisfies the other two equations among equations (1), (2), and (4). , The parameters of one remaining expression within the range.

The degree of atomization is represented by SMD (Sauter Mean Diameter, Sauter mean particle size). 1) From FIG. 4 (A), when DS / DH value is in the range of 1.5 to 6, 2) From FIG. 4 (B). In the range where the value of 1.5 d-h is 0 or more, and 3) the value of SMD is less than 100 μm in the range where the value of 4 d-H (mm) is 0 or more from FIG. It turns out that it can be realized.

FIGS. 5 and 6 show a state in which the fuel injection valve 10 is attached to the intake pipe. The engine shown in FIGS. 5 and 6 is a three-cylinder engine. The fuel injection valve 10 is an intake pipe that is upstream of the gathering portion 3 of the intake distribution pipes 2a, 2b, and 2c of the intake manifold 2 that is connected to each cylinder on the downstream side of the intake flow, and that is downstream of the throttle valve (not shown). 1 5 and 6 indicate the spray range of the fuel injection valve 10.

Since the fuel injection valve 10 of the present embodiment can inject atomized fuel over a wide range as shown in FIGS. 5 and 6, one fuel injection valve uniformly and uniformly applies to each cylinder. Can be supplied with fuel. Therefore, the number of parts is small and the control of the fuel injection valve is simplified as compared with the case where the fuel injection valve is attached to each cylinder, so that the manufacturing cost is reduced. In particular, it is effective to mount the fuel injection valve 10 of this embodiment on a small engine.

Next, the operation of the fuel injection valve 10 will be described.

(1) When the power to the electromagnetic coil 50 is turned off, the movable core 22 and the needle valve 25 are urged downward in FIG. 2 by the urging force of the compression coil spring 26, and the contact portion 25b of the needle valve 25 is moved to the valve seat 31b. To sit down. Thereby, the fuel injection from the orifices 32a and 32b is shut off.

(2) When the power supply to the electromagnetic coil 50 is turned on, the movable core 22 is attracted to the fixed core 21 against the urging force of the compression coil spring 26, so that the contact portion 25b of the needle valve 25 is moved from the valve seat 31b. Leave. Thereby, fuel flows into the fuel chamber 35 from the opening of the contact portion 25b and the valve seat 31b. The fuel that has flowed into the fuel chamber 35 travels toward the center of the fuel chamber 35. The fuel toward the center collides with each other at the center to generate a radially outward flow, and the radially outward fuel flow and the centrally directed fuel flow collide on the orifices 32a and 32b. Then, the atomized fuel is injected from the orifices 32a and 32b.

(Modification 1)
FIG. 7 shows a first modification of the present embodiment.

(4) Four orifices 71 and 72 are formed concentrically, each of which is eight in total, and the orifice 71 is located on the inner peripheral side of the orifice 72. In order to inject the same amount of fuel as in the above-described reference example, the diameter of each orifice is larger than in the above-described reference example. In the first modification as well, since the axis of line symmetry cannot be drawn without passing through each orifice, it is a one-way injection.

In the first modification as well, the atomization of the fuel spray injected from the orifices 71 and 72 is promoted, as in the above-described reference example.

(Modification 2)
FIG. 8 shows a second modification of the present embodiment.

A total of 12 orifices 73 and 74 are formed on concentric circles, each having n1 = 4 and n2 = 8, and the orifice 73 is located on the inner peripheral side of the orifice 74. The diameter of each orifice is the same as that of the reference example described above. In the second modification, an axis having a line symmetry can be drawn without passing through each orifice. That is, according to the arrangement of the second modification, the spray is in two directions.

In the second modification as well, the atomization of the fuel spray injected from the orifices 73 and 74 is promoted in the same manner as in the above-described reference example.

(Modification 3)
FIG. 9 shows a third modification of the present embodiment.

The orifices 75 and 76 are formed on the concentric circle, each having a total of six, n1 = 2 and n2 = 4, and the orifice 75 is formed on the inner peripheral side of the orifice 76. In order to inject the same amount of fuel as in the above-described reference example, the diameter of each orifice is larger than in the first modification. In the third modification, an axisymmetric axis can be drawn without passing through each orifice. That is, according to the arrangement of the third modification, the spray is in two directions.

In the third modification as well, the atomization of the fuel spray injected from the orifices 75 and 76 is promoted in the same manner as in the above-described reference example.

In the above-described first reference example and the modified examples of the present invention, the diameters of the orifices on the inner peripheral side and the outer peripheral side are the same, but may be different values on the inner peripheral side and the outer peripheral side.
Further, if the expressions (1), (2), and (4) are satisfied, the orifices do not have to be arranged so that circles of the same diameter can be secured almost in contact with each other. Further, if the orifices are arranged so that circles of the same diameter can be secured almost in contact with each other with each orifice as a center, formulas (1), (2) and (4) do not have to be satisfied.

(Second reference example)
FIG. 10 shows a second reference example of the present invention.

The distal end of the needle valve 80 includes a distal end surface 80a, a contact portion 80b, and an annular curved surface 80c connecting the distal end surface 80a and the contact portion 80b. The contact portion 80b can be seated on a valve seat 82a provided on a conical slope 82 as an inner wall surface of the valve body 81. The distal end surface 80a is formed on the inner peripheral side of the contact portion 80b in a planar shape so as to be substantially parallel to the opposing surface 83a of the orifice plate 83, that is, to be substantially equidistant from the opposing surface 83a in the surface spreading direction.

内径 The inner diameter of the valve body 81 is reduced from the vicinity of the distal end toward the orifice plate 83, and a conical slope 82 is formed on the inner wall surface forming a fuel passage as a fluid passage on the orifice plate 83 side. The contact portion 80b of the needle valve 80 can be seated on a valve seat 82a formed on the conical slope 82.

The orifice plate 83 is formed with a total of four orifices 84 having the same diameter d that penetrate the orifice plate 83 in the thickness direction. The orifice 84 is a virtual envelope line connecting the position where the direction of the main fuel flow downstream of the contact portion 80b intersects with the facing surface 83a. In FIG. 10, the orifice 84 is the intersection of the virtual extension surface of the conical slope 82 and the facing surface 83a. It is formed inside.

{The axial distance h of the needle valve 80 between the distal end surface 80a and the opposing surface 83a when the needle is opened and the diameter d of the orifice 84 of the orifice plate 83 are set so as to satisfy Expression (1)}. The vertical distance H between the valve seat 82a and the facing surface 83a and the diameter d of the orifice 84 are set so as to satisfy Expression (2).

The orifice 84 is inclined so as to move away from the central axis of the needle valve 80 toward the fuel downstream side. Assuming that the inclination angle of the orifice 84 with respect to the center axis of the needle valve 80 is θ, θ satisfies the following expression (5).

15 ° ≦ θ (desirably 20 ° ≦ θ) (5)
Assuming that the pitch of each orifice 84 on the facing surface 83a is DH and the seat diameter of the needle valve 80 is DS, DH and DS satisfy the following expression (6).

1.5 <DS / DH <6 (6)
With the above configuration, the fuel flow flowing into the fuel chamber 85 as a fluid chamber defined by the front end face 80a, the conical slope 82, and the opposing face 83a is not directly injected from each orifice 84 to the orifice plate 83. Since the fuel is injected after being changed direction after the collision and colliding with each other immediately above the orifice, the atomization of the fuel spray injected from the orifice 84 is promoted similarly to the first embodiment.

(First embodiment)
FIG. 11 shows a first embodiment of the present invention. In the following embodiments, the description of the same configurations as those of the first reference example, its modifications, and the second reference example will be omitted, and only different configurations will be described.

先端 The distal end of the needle valve 86 includes a distal end surface 86a and a contact portion 86b. The distal end surface 86a is formed in a convex spherical shape protruding to the fuel downstream side on the inner peripheral side of the contact portion 86b. The contact portion 86b can be seated on the valve seat 82a.

The orifice plate 87 is formed by pressing a flat plate member on which an orifice 88 has been formed in advance with, for example, a punch having a spherical tip to make it concave. The opposing surface 87a of the orifice plate 87 is formed in a concave spherical shape so that the distance between the opposing surface 87a and the distal end surface 86a is substantially equal to the shape of the distal end surface 86a. Here, the opposed surface 87a represents a surface within a range where the orifice plate 87 is exposed to the fuel flowing when the needle valve 86 is separated from the valve seat 82a. Further, that the distance between the distal end surface 86a and the opposing surface 87a is substantially equal means that the length of the common perpendicular dropped on the distal end surface 86a and the opposing surface 87a is approximately equal in the plane spreading direction at an arbitrary needle valve lift position. In the orifice plate 87, a total of four orifices 88 having the same diameter d are formed penetrating the orifice plate 87 in the thickness direction. The orifice 88 is a virtual envelope line connecting the position where the direction of the main fuel flow downstream of the contact portion 86b intersects the opposing surface 87a, and in FIG. 11, the intersection line between the virtual extension surface of the conical slope 82 and the opposing surface 87a. It is formed inside.

距離 The distance h between the distal end surface 86a and the opposing surface 87a when the needle is opened and the diameter d of the orifice 88 are set so as to satisfy Expression (1). Here, the distance h represents the length of the shortest common perpendicular dropped to the distal end surface 86a and the opposing surface 87a when the needle is opened. The vertical distance H from the valve seat 82a to the imaginary plane passing through the outer peripheral edge of the facing surface 87a and orthogonal to the central axis of the needle valve 86 and the diameter d of the orifice 88 are set so as to satisfy Expression (2).

The orifice 88 is inclined so as to become farther from the center axis of the needle valve 86 toward the downstream side of the fuel. Assuming that the inclination angle of the orifice 88 with respect to the center axis of the needle valve 86 is θ, θ is represented by Expression (5). Meets.
Assuming that the pitch of each orifice 88 on the facing surface 87a is DH and the seat diameter of the needle valve 86 is DS, DH and DS satisfy Expression (6).

In the first embodiment, the orifice plate 87 is recessed downstream of the fuel in accordance with the tip shape of the needle valve 86. Therefore, when the plate member having the orifice formed in advance is recessed, the orifice plate is deviated from the center axis of the needle valve 86. 88 moves further away. Thus, even if the orifice has a large inclination angle, which is difficult to machine with a flat orifice plate, the inclination angle of the orifice with respect to the center axis of the needle valve is reduced by recessing the orifice plate in accordance with the shape of the tip surface of the needle valve. Can be easily enlarged, and the fuel spray angle can be enlarged. Therefore, it is possible to easily manufacture a fuel injection valve that requires a large spray angle in order to inject the spray directly below the nozzle into the combustion chamber as close as possible to the intake valve.

Further, the fuel flow that has flowed into the fuel chamber 89 as a fluid chamber defined by the front end surface 86a, the conical slope 82, and the opposing surface 87a is not directly injected from each orifice 88 but collides with the orifice plate 87 and then turns. Alternatively, since the fuel is injected after colliding with each other immediately above the orifice, the atomization of the fuel spray injected from the orifice 88 is promoted as in the first embodiment.

(Second embodiment)
FIG. 12 shows a second embodiment of the present invention.

先端 The distal end of the needle valve 90 is composed of a distal end face 90a and a contact part 90b. The distal end surface 90a is formed in a convex conical shape on the inner peripheral side of the contact portion 90b and protrudes downstream of the fuel. The contact portion 90b can be seated on the valve seat 82a.

The orifice plate 91 is formed by pressing a flat plate member on which the orifice 92 is formed in advance with a punch having a conical tip, for example. The opposing surface 91a of the orifice plate 91 is formed in a concave conical shape so that the distance between the opposing surface 91a and the distal end surface 90a is substantially equal to the shape of the distal end surface 90a. Here, the facing surface 91a represents a surface within a range that is exposed to the fuel that flows in when the needle valve 90 is separated from the valve seat 82a. Further, that the distance between the distal end surface 90a and the opposing surface 91a is substantially equal means that the length of the common perpendicular dropped on the distal end surface 90a and the opposing surface 91a is approximately equal in the plane spreading direction at an arbitrary lift position of the needle valve 90. Represent. In the orifice plate 91, a total of four orifices 92 having the same diameter d are formed penetrating the orifice plate 91 in the thickness direction. The orifice 92 is a virtual envelope line connecting the position where the direction of the main fuel flow downstream of the contact portion 90b intersects the opposing surface 91a, and in FIG. 12, the intersection line between the virtual extension surface of the conical slope 82 and the opposing surface 91a. It is formed inside.

距離 The distance h between the distal end face 90a and the opposing face 91a when the needle is opened and the diameter d of the orifice 92 are set so as to satisfy Expression (1). Here, the distance h represents the length of the shortest common perpendicular dropped to the distal end face 90a and the opposing face 91a when the needle is opened. The vertical distance H from the valve seat 82a to the imaginary plane passing through the outer peripheral edge of the facing surface 91a and orthogonal to the central axis of the needle valve 90, and the diameter d of the orifice 92 are set so as to satisfy Expression (2).

The orifice 92 is inclined so as to move away from the central axis of the needle valve 90 toward the downstream side of the fuel. If the inclination angle of the orifice 92 with respect to the central axis of the needle valve 90 is θ, θ is given by the following equation (5). Meets. Assuming that the pitch of each orifice 92 on the facing surface 91a is DH and the seat diameter of the needle valve 90 is DS, DH and DS satisfy Expression (6).

Also in the second embodiment, as in the first embodiment, the orifice plate 91 is recessed on the fuel downstream side according to the tip shape of the needle valve 90, so that the inclination angle of the orifice with respect to the central axis of the needle valve can be easily enlarged. Thus, the fuel spray angle can be increased. Therefore, a fuel injection valve requiring a large spray angle can be easily manufactured.

Further, the fuel flow that has flowed into the fuel chamber 93 as a fluid chamber defined by the front end face 90a, the conical slope 82, and the opposed face 91a is not directly injected from each orifice 92, but is directed after colliding with the orifice plate 91. Alternatively, since the fuel is injected after colliding with each other immediately above the orifice, the atomization of the fuel spray injected from the orifice 92 is promoted as in the first embodiment.

In each of the above-described embodiments, when the needle valve and the valve body are separated from each other, part of the fuel flowing from the entire circumference toward the center of the orifice plate is changed in direction at the center of the orifice plate, Make a U-turn to each orifice. The fuel flow that makes a U-turn from the center of the orifice plate collides with the flow flowing from the outer periphery of the orifice plate to the orifice at the center of the orifice inlet.

The intensity of the flow flowing into the orifice after making a U-turn at the center of the orifice plate is almost the same as the flow flowing into the orifice from the outer periphery of the orifice plate. It can be atomized. At the same time, the fuel collides at the center of the inlet of the orifice, and a uniform collision is obtained. Therefore, the directionality of the atomized fuel is well controlled by the orifice.

Since the atomization of the fuel spray injected from the orifice is promoted in this manner, the fuel spray is easily mixed with air over a wide range, and the combustion efficiency of the fuel is increased. And the fuel consumption can be reduced.

FIG. 2 is a cross-sectional view illustrating an injection nozzle portion of a fuel injection valve according to a first reference example of the present invention. (A) is a plan view showing the arrangement of the orifices of the first reference example, (B) is a sectional view taken along line BB of (A), and (C) is a sectional view taken along line CC of (A). It is. It is a longitudinal section showing the fuel injection valve of the 1st example. (A) is a characteristic diagram showing a relationship between DS / DH and SMD, (B) is a characteristic diagram showing a relationship between 1.5 dh and SMD, and (C) is a characteristic diagram showing 4d-H and SMD. FIG. 6 is a characteristic diagram showing the relationship of FIG. FIG. 4 is a plan view showing a state in which the fuel injection valve of the first reference example is mounted on an intake pipe. FIG. 6 is a view in the direction of arrow VI in FIG. 5. FIG. 7 is a plan view showing an arrangement of orifices according to a first modification of the first reference example. FIG. 11 is a plan view showing an arrangement of orifices according to a second modification of the first reference example. FIG. 14 is a plan view showing an arrangement of orifices according to a third modification of the first reference example. FIG. 5 is a cross-sectional view illustrating an injection nozzle portion of a fuel injection valve according to a second reference example of the present invention. FIG. 2 is a cross-sectional view illustrating an injection nozzle portion of the fuel injection valve according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating an injection nozzle of a fuel injection valve according to a second embodiment of the present invention.

Explanation of reference numerals

Reference Signs List 10 fuel injection valve 21 fixed core 22 movable core 25, 80, 86, 90 needle valve (valve member)
25a, 80a, 86a, 90a Tip surface 25b, 80b, 86b, 90b Contact portion 30, 81 Nozzle body 31 Inner wall surface 31a, 82 Conical slope 31b, 82a Valve seat 32, 83, 87, 91 Orifice plate 32a, 32b, 71, 72, 73, 74, 75, 76, 84, 88, 92 Orifices 33, 83a, 87a, 91a Opposing surfaces 35, 85, 89, 93 Fuel chamber (fluid chamber)

Claims (9)

A valve body having a valve seat on an inner wall surface forming a fluid passage;
A valve member having an abutting portion capable of being annularly seated on the valve seat, wherein the abutting portion opens and closes the fluid passage by separating from and seating on the valve seat;
An orifice plate provided in the valve body on the fluid downstream side of the valve member, and an orifice plate having a plurality of orifices penetrating in a plate pressure direction,
A surface of the orifice plate facing the valve member, a distal end surface formed on the inner peripheral side of the contact portion at a downstream distal end portion of the valve member, and a substantially disk-shaped fluid chamber formed by the inner wall surface. Forming
The distal end surface of the valve member is formed in a convex spherical shape or a convex conical shape protruding toward the fuel downstream side on the inner peripheral side of the contact portion,
A fuel injection nozzle characterized in that the orifice plate is recessed downstream of the fuel. The fuel injection nozzle according to claim 1, wherein the orifices are arranged on a double concentric circle. If the inclination angle of the orifice on the inner peripheral circle of the double concentric circle with respect to the center axis of the valve member is θ1, and the inclination angle of the orifice on the outer peripheral circle of the double concentric circle is θ2, θ1 <θ2. The fuel injection nozzle according to claim 2, wherein: 4. The orifice according to claim 1, wherein the orifice is formed inside a virtual envelope connecting a position where a main flow direction of the fluid downstream of the contact portion intersects with the facing surface. 4. The fuel injection nozzle according to claim 1. 5. The fuel injection according to claim 1, wherein 0.5 <t / d <1.0, where t is a thickness of the orifice plate and d is a diameter of the orifice. 6. nozzle. The fuel injection nozzle according to claim 1, wherein d <0.25 mm, where d is the diameter of the orifice. The fuel injection nozzle according to any one of claims 1 to 6, wherein the orifice is inclined at an angle of 15 degrees or more in a direction away from a center axis of the valve member toward the downstream side of the fluid. The fuel injection nozzle according to any one of claims 1 to 7, wherein the orifice is inclined with respect to a center axis of the valve member in a direction away from the center axis. A fuel injection device having a fuel injection nozzle according to any one of claims 1 to 8 is mounted downstream of a throttle valve and upstream of a collection portion of an intake distribution pipe connected to each cylinder. Fuel supply device.

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