JP3726830B2 - Fuel injection nozzle and fuel supply device - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection nozzle and a fuel supply device. is there.

In such a fuel injection valve, from the viewpoints of reducing fuel consumption, improving exhaust emission, stable engine operability, etc., "fuel atomization" injected from the nozzle holes is one of the important factors. is there. As a method for promoting 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 these atomizing means are all expensive. There is a problem.

On the other hand, for example, a fuel injection valve disclosed in Patent Document 1 is known as an apparatus in which an orifice plate having an orifice formed at the tip of a fuel injection valve is provided to promote atomization. In this fuel injection valve, a configuration in which a recess is formed at the tip of the needle valve and a configuration in which the needle tip is formed flat at right angles to the needle axial direction are disclosed.
US Pat. No. 5,383,607

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

  Further, in the configuration in which the needle tip is formed flat at right angles to the needle axial direction, the orifice plate is recessed with respect to the needle valve, so that the fuel spreads in the axial direction between the needle tip surface and the orifice plate. Therefore, 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, paying attention to a phenomenon in which turbulence due to collision of fluid flow greatly affects atomization.
Another object of the present invention is to provide a fuel injection nozzle that suppresses the atomized fluid spray from overlapping at the injection destination.

According to the first to eighth aspects of the invention, 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 are substantially discs. The tip end surface of the valve member is formed in a convex spherical shape or a convex conical shape projecting on the fuel downstream side on the inner peripheral side of the contact portion, and the orifice plate is recessed on the fuel downstream side. it is characterized in that was.

  As a result, the fluid chamber can be flattened, a flow along the opposing surface of the orifice plate can be created, and a collision between the fluid flows can be induced.

  Therefore, the fluid ejected from the orifice plate is atomized by turbulence due to collision, and becomes a spray having directionality.

In the invention described in claim 1, since the orifice is formed inside the intersection line between the virtual extension line and the opposed surface of the orifice plate , the orifice is directly connected to the orifice plate without colliding with the orifice plate. The main fluid flow can be prevented from being ejected.

Accordingly, the main fluid flow that collides with the orifice plate changes direction along the orifice plate and collides with other fluid flows. The fluid ejected from the orifice is atomized by turbulence due to collision, and becomes a directional spray.

In the inventions according to claims 1 to 8, the orifices are arranged on a double concentric circle, and a line connecting the inner peripheral orifice and the central axis of the orifice plate is shifted in the circumferential direction from the outer peripheral orifice. Therefore, the atomized spray injected from each orifice can be prevented from overlapping at the injection destination, and the atomized spray can be supplied uniformly.

The invention according to claim 3 is characterized in that the inclination angle of the outer peripheral side orifice is larger than the inclination angle of the inner peripheral side orifice, so that the spray injected from the outer peripheral side orifice and the inner peripheral side It is possible to prevent overlap with spray sprayed from the orifice. Therefore, the atomized spray can be supplied uniformly.
In the invention according to claim 4 , there is a relationship of 0.5 <t / d <1.0 between the thickness t of the orifice plate and the diameter d of the orifice. If 0.5 ≧ t / d, the direction of fluid spray injected from the orifice is not stable. Further, if t / d ≧ 1.0, the atomized spray while passing through the orifice causes re-adhesion, 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.

Further, according to the invention described in claim 5, 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 further increased. By increasing the amount, atomization can be further promoted.

In addition, according to the sixth and seventh aspects of the invention, since the spray angle of the fluid ejected from the orifice can be expanded, the fluid can be ejected over a wide range.

  Thereby, since the spray angle of the fluid ejected from the orifice can be expanded, the fluid can be ejected over a wide range.

  Further, by indenting the orifice plate, a fluid ejection nozzle that requires a large ejection angle can be easily manufactured.

According to an eighth aspect of the present invention, the fuel injection device having any one of the fuel injection nozzles according to any one of the first to seventh aspects is disposed downstream of the throttle valve and upstream of the collecting pipe connecting to each cylinder. By mounting on the cylinder, uniform fuel spray can be uniformly supplied to each cylinder by one fuel injection device. Therefore, it is particularly suitable when mounted on a small engine.

  Embodiments and reference examples of the present invention will be described below with reference to the drawings.

(First Reference Example)
As a first reference example of the present invention, a fuel injection nozzle applied to a fuel injection valve of a fuel supply device for a gasoline engine is shown in FIGS.

As shown in FIG. 3, the 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 disposed in the internal space of the nonmagnetic 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 nonmagnetic pipe 23 is fitted to the outer periphery of the fixed core 21 at the end of the movable core and is 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 the end of the non-magnetic pipe 23 on the side opposite to the fixed core. The non-fixed core side of the nonmagnetic pipe 23 forms a guide part for the movable core 22. As shown in FIG. 1, the tip end surface 25a on the fuel injection side of the needle valve 25 as a valve member is formed in a gentle conical convex shape whose diameter gradually decreases toward the fuel flow, and the contact portion 25b. Can be seated in an annular shape on a valve seat 31 b provided in the valve body 30. A joint portion 25d is formed at the other end of the needle valve 25 as shown in FIG. Then, the joint portion 25d and the movable core 22 are laser welded, and the needle valve 25 and the movable core 22 are integrally connected. Two chamfering as a fuel passage is provided on the outer periphery of the joint portion 25d.

  The valve body 30 is inserted into the magnetic pipe 24 through 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 stainless steel orifice plate 32 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, all-around welding.

  The sleeve 40 is made of resin and is press-fitted into 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 32a and 32b formed in the orifice plate 32 is injected from the opening 40a of the sleeve 40 into the engine.

  One end of the compression coil spring 26 is in contact with a spring seat 22 a provided on the movable core 22, and the other end of the compression coil spring 26 is in contact with 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 25 b is seated on the valve seat 31 b of the valve body 30.

  The adjusting pipe 27 is press-fitted into the inner periphery of the fixed core 21. The biasing force of the compression coil spring 26 can be adjusted by adjusting the press-fitting position of the adjusting pipe 27 during assembly.

  The electromagnetic coil 50 is wound around the outer periphery of a spool 51 made of resin, and the spool 51 is disposed on the outer periphery of the fixed core 21, the nonmagnetic pipe 23, and the magnetic pipe 24. The housing mold 11 is resin-molded on the outer periphery of the electromagnetic coil 50 and the spool 51, and the electromagnetic coil 50 is surrounded by the housing mold 11. When an exciting current flows from the terminal 52 to the electromagnetic coil 50 via the lead wire by an electronic control device (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 device (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 path. 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 matters such as dust in the fuel that is pumped from the 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 portion formed at the joint portion 25d of the needle valve 25, and the sliding 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 composed of the contact portion 25b of the needle valve 25 and the valve seat 31b. As shown in FIG. 1, when the contact portion 25b is separated from the valve seat 31b, the fuel flows into the fuel chamber 35 through an opening formed by the contact portion 25b and the valve seat 31b.

  The fuel chamber 35 as a fluid chamber is partitioned by an opposed surface 33 of the orifice plate 32, a conical inclined surface 31a of the valve body 30, and a tip surface 25a, and is formed in a substantially disc 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, an abutting portion 25b, and an annular curved surface 25c that connects the distal end surface 25a and the abutting 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. A distance h in the axial direction of the needle valve at the time of needle opening between the front end surface 25a and the opposed surface 33 of the orifice plate 32 and a diameter d of orifices 32a and 32b described later of the orifice plate 32 satisfy the following expression (1). Is set to

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

  Further, since the orifice diameter is small, it is easy to form a fuel passage between the orifices in the orifice plate having a predetermined area. Therefore, as will be described later, the DS / DH value 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 = 0.15 or so.

  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 inclined surface 31a of the valve body 30 so that the gap between the contact portion 25b and the conical inclined surface 31a is set to the orifice plate. This is because the fuel advances toward the side 32 and hits the facing surface 33 of the orifice plate 32 to bend 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 orifices and a flow passing between the orifices, and the flow passing between the orifices is U-turned by the opposing flow at the center of the orifice plate and becomes a flow toward the orifices. The fuel flows from these opposite radial directions to the orifice collide with each other immediately above the orifice, creating an unstable flow state and promoting fuel atomization.

  That is, since the distance h and the diameter d are set so as to satisfy the formula (1), the fuel can flow in a narrow gap between the tip surface 25a and the facing surface 33, and the fuel flows along the facing surface 33 Can induce collisions. Thereby, the energy of collision between fuels can be increased to 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 inclined surface 31a is formed on the orifice plate 32 side of the inner wall surface 31 forming a fuel passage as a fluid passage. 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, a valve seat 31 b that is an inlet of fuel to the fuel chamber 35 is set close to the orifice plate 32.

  The conical slope 31a is reduced in diameter 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 the formula (2). Therefore, when the needle valve 25 and the valve body 30 are separated from each other, the fuel flowing into the fuel chamber 35 along the conical inclined surface 31a from the space between the contact 25b and the valve seat 31b is caused to follow the facing 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 plate thickness direction as shown in FIG. . As shown in FIG. 1, the orifices 32 a and 32 b are virtual envelope lines connecting positions where the direction of the main fuel flow on the downstream side of the abutting portion 25 b intersects the facing surface 33, in FIG. It 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 by contacting each other with the same radius from the center of each orifice. Therefore, since the area | region where the spray injected from each orifice is substantially equal can be ensured, it is difficult for the spray to overlap at the injection destination.

  Further, as shown in FIGS. 2B and 2C, the orifices 32a and 32b are inclined so as to move away from the central axis toward the fuel downstream side of the orifice plate 32. Assuming that the inclination angles of the orifices 32a and 32b are θ1 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 injected from the orifices 32a and 32b are uniformly atomized without overlapping each other.

  If the number of orifices 32a is n1 and the number of orifices 32b is n2, n1 = n2. If the orifices 32a and 32b are arranged so that the distribution of the number of orifices is made equal as described above and the circles can be secured by contacting each other 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 this reference example, the spray is in one direction.

  As shown in FIG. 1, when the pitch between the orifices 32a and 32b is DH0 and DH1, and the seat diameter of the needle valve 25 is DS, 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 inclined surface 31a and then directly into the orifice. After the direction is changed by the facing surface 33 of the orifice plate 32 without flowing in, it advances a predetermined distance between the facing surface 33 and the flat surface 25a. Therefore, the main flow of fuel does not directly flow into the orifices 32a and 32b, and the fuel can be efficiently atomized. Further, by satisfying the expression (4), the orifices 32a and 32b can be disposed within a range that does not approach the center of the orifice plate 32 and does not extend too far to the outer peripheral side of the orifice plate 32. Therefore, the strength of the fuel flow flowing into each of the orifices 32a and 32b can be made almost equal regardless of the inflow 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.

  Further, since a uniform collision can be obtained at the center of the inlet of the orifice, it is possible to obtain a spray with extremely good direction along the inclination of the entire circumference of the side wall forming the orifice.

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

  The degree of atomization is represented by SMD (Sauter Mean Diameter, Sauter average particle diameter), 1) DS / DH values in the range of 1.5-6 from FIG. 4 (A), 2) From FIG. 4 (B). The value of 1.5 d-h is in the range of 0 or more, 3) From FIG. 4C, the value of 4d-H (mm) is in the range of 0 or more, the SMD value is less than 100 μm, respectively, and good atomization It can be seen that it can be realized.

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

  Since the fuel injection valve 10 of the present reference example can inject the atomized fuel over a wide range as shown in FIGS. 5 and 6, it is evenly and evenly applied to each cylinder by one fuel injection valve. Can be supplied with fuel. Therefore, the manufacturing cost is reduced because 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. 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 energization of 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. Sit down. As a result, fuel injection from the orifices 32a and 32b is blocked.

  (2) When energization of 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 removed from the valve seat 31b. Take a seat. As a result, fuel flows into the fuel chamber 35 from the opening between 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 central portion collides with each other at the central portion to generate a radially outward flow, and the radially outward fuel flow and the fuel flow toward the central portion collide on the orifices 32a and 32b. The atomized fuel is injected from the orifices 32a and 32b.

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

  Four orifices 71 and 72 are formed on each concentric circle, for a total of eight, 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 the reference example described above, the diameter of each orifice is larger than that of the reference example described above. In the first modified example, a line-symmetric axis cannot be drawn without passing through each orifice, so that the unidirectional injection is performed.

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

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

  A total of 12 orifices 73 and 74 are formed on the concentric circle, n1 = 4 and n2 = 8, respectively, and the orifice 73 is located on the inner peripheral side of the orifice 74. The diameter of each orifice is the same as in the reference example described above. In the second modification, a line-symmetric axis can be drawn without passing through each orifice. That is, according to the arrangement of the modification example 2, the spray is in two directions.

  Also in the modified example 2, atomization of the fuel spray injected from the orifices 73 and 74 is promoted similarly to the reference example described above.

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

  A total of six orifices 75 and 76 are formed on the concentric circle, n1 = 2 and n2 = 4, respectively, 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 reference example described above, the diameter of each orifice is larger than that in the first modification. In the third modification, a line-symmetric axis can be drawn without passing through each orifice. That is, according to the arrangement of the modification 3, the spray is in two directions.

  In the modified example 3, as in the reference example described above, atomization of the fuel spray injected from the orifices 75 and 76 is promoted.

In the first reference example of the present invention described above and the modification thereof, the diameters of the orifices on the inner peripheral side and the outer peripheral side are the same, but different values may be used on the inner peripheral side and the outer peripheral side.
In addition, as long as the expressions (1), (2), and (4) are satisfied, the orifices do not have to be arranged so that circles having the same diameter can be secured substantially in contact with each other. Further, if the orifices are arranged so that circles of the same diameter can be ensured almost in contact with each other at the center, the equations (1), (2), and (4) may not be satisfied.

(Second reference example)
A second reference example of the present invention is shown in FIG.

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

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

  The orifice plate 83 is formed with a total of four orifices 84 having a diameter d passing through the orifice plate 83 in the thickness direction. The orifice 84 is a virtual envelope line connecting the positions where the direction of the main fuel flow on the downstream side of the abutment portion 80b intersects the opposing surface 83a, and in FIG. 10, the intersection line between the virtual extension surface of the conical slope 82 and the opposing surface 83a. It is formed inside.

  The distance h in the axial direction of the needle valve 80 between the tip surface 80a and the opposed surface 83a when the needle is opened and the diameter d of the orifice 84 of the orifice plate 83 are set 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 the formula (2).

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

15 ° ≦ θ (desirably 20 ° ≦ θ) (5)
When the pitch of the orifices 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-described configuration, the fuel flow that has flowed into the fuel chamber 85 as a fluid chamber defined by the tip surface 80a, the conical inclined surface 82, and the facing surface 83a is not directly injected from each orifice 84 to the orifice plate 83. Since the direction is changed after the collision and the fuel is injected after colliding with each other immediately above the orifice, atomization of the fuel spray injected from the orifice 84 is promoted as in the first reference example.

(First embodiment)
A first embodiment of the present invention is shown in FIG. In the following embodiments, the description of the same configurations as those of the first reference example, the modifications thereof, and the second reference example will be omitted, and only the configurations different from these will be described.

  The distal end portion of the needle valve 86 includes a distal end surface 86a and an abutting portion 86b. The tip end face 86a is formed in a convex spherical shape that protrudes toward 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, for example, pressing and denting a flat plate member on which the orifice 88 has been formed in advance with a punch having a spherical tip. The facing surface 87a of the orifice plate 87 is formed in a concave spherical shape so that the distance from the front end surface 86a is substantially equal to the shape of the front end surface 86a. Here, the facing surface 87a represents a surface within a range in which the orifice plate 87 is exposed to the fuel flowing in when the needle valve 86 is separated from the valve seat 82a. Further, that the distance between the tip surface 86a and the facing surface 87a is substantially equal means that the length of the common perpendicular dropped on the tip surface 86a and the facing surface 87a is substantially equal in the surface spreading direction at an arbitrary needle valve lift position. The orifice plate 87 is formed with a total of four orifices 88 having the same diameter d passing through the orifice plate 87 in the thickness direction. The orifice 88 is a virtual envelope line connecting the positions where the direction of the main fuel flow on the downstream side of the abutting 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.

  The distance h between the tip surface 86a and the opposed surface 87a and the diameter d of the orifice 88 when the needle is opened are set so as to satisfy the formula (1). Here, the distance h represents the length of the shortest common perpendicular dropped to the tip surface 86a and the opposing surface 87a when the needle is opened. The vertical distance H from the valve seat 82a to the virtual 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).

Further, the orifice 88 is inclined so as to be away from the central axis of the needle valve 86 as it goes downstream of the fuel. When the inclination angle of the orifice 88 with respect to the central axis of the needle valve 86 is θ, θ is expressed by the following equation (5). Meet.
When the pitch of the orifices 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, since the orifice plate 87 is recessed toward the fuel downstream side in accordance with the tip shape of the needle valve 86, when the flat plate member on which the orifice has been formed is recessed, the orifice plate 87 is displaced from the central axis of the needle valve 86. 88 goes further. As a result, even if the orifice plate has a large inclination angle, which is difficult to process with a flat orifice plate, the inclination angle of the orifice with respect to the central axis of the needle valve can be reduced by denting the orifice plate in accordance with the shape of the tip surface of the needle valve. The fuel spray angle can be expanded easily. Therefore, it is possible to easily manufacture a fuel injection valve that requires a large spray angle in order to inject spray directly under the nozzle as close as possible to the intake valve into the combustion chamber.

  Further, the fuel flow that has flowed into the fuel chamber 89 as a fluid chamber defined by the tip surface 86a, the conical inclined surface 82, and the opposed surface 87a is not directly injected from each orifice 88, but is directed after it collides with the orifice plate 87. Instead, since the fuel is injected after colliding with each other immediately above the orifice, atomization of the fuel spray injected from the orifice 88 is promoted as in the first reference example.

(Second embodiment)
A second embodiment of the present invention is shown in FIG.

  The distal end portion of the needle valve 90 includes a distal end surface 90a and an abutting portion 90b. The distal end surface 90a is formed in a convex conical shape that protrudes toward the fuel downstream side on the inner peripheral side of the contact portion 90b. The contact portion 90b can be seated on the valve seat 82a.

  The orifice plate 91 is formed by, for example, pressing and denting a flat plate member in which the orifice 92 is formed in advance with a punch having a conical tip. The facing surface 91a of the orifice plate 91 is formed in a concave conical shape so that the distance from 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 exposed to the fuel flowing in when the needle valve 90 is separated from the valve seat 82a. Further, that the distance between the tip surface 90a and the facing surface 91a is substantially equal means that the length of the common perpendicular dropped on the tip surface 90a and the facing surface 91a is substantially equal in the surface spreading direction at the lift position of any needle valve 90. Represent. The orifice plate 91 is formed with a total of four orifices 92 having a diameter d passing through the orifice plate 91 in the thickness direction. The orifice 92 is a virtual envelope line connecting the positions where the direction of the main fuel flow on the downstream side of the contact portion 90b intersects the opposing surface 91a. In FIG. 12, the intersection line between the virtual extension surface of the conical inclined surface 82 and the opposing surface 91a. It is formed inside.

  The distance h between the distal end surface 90a and the opposed surface 91a and the diameter d of the orifice 92 when the needle is opened are set so as to satisfy the formula (1). Here, the distance h represents the length of the shortest common perpendicular dropped to the tip surface 90a and the facing surface 91a when the needle is opened. The vertical distance H from the valve seat 82a to the virtual 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 to satisfy Expression (2).

  Further, the orifice 92 is inclined so as to move away from the central axis of the needle valve 90 as it goes downstream of the fuel. When the inclination angle of the orifice 92 with respect to the central axis of the needle valve 90 is θ, θ is expressed by the equation (5). Meet. When the pitch of the orifices 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, the orifice plate 91 is recessed toward the fuel downstream side in accordance with the tip shape of the needle valve 90 as in the first embodiment, so that the inclination angle of the orifice with respect to the central axis of the needle valve can be easily expanded. In addition, the fuel spray angle can be expanded. Therefore, a fuel injection valve that requires 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 tip surface 90a, the conical inclined surface 82, and the facing surface 91a is not directly injected from each orifice 92, but is directed after the collision with the orifice plate 91. Instead, since the fuel is injected after colliding with each other immediately above the orifice, atomization of the fuel spray injected from the orifice 92 is promoted as in the first embodiment.

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

  The strength of the flow that flows into the orifice after making a U-turn in the center of the orifice plate is almost the same as the flow that flows into the orifice from the periphery of the orifice plate, so that it is possible to obtain a uniform collision with no vortex around the orifice. Atomization is possible. At the same time, the fuel collides at the center of the inlet of the orifice, and a uniform collision can be obtained. Therefore, the directionality of the atomized fuel is well controlled by the orifice.

  By promoting atomization of the fuel spray injected from the orifice in this way, the fuel spray is easily mixed with air over a wide range, and the combustion efficiency of the fuel is increased. Therefore, harmful substances discharged into the exhaust gas In addition, fuel consumption can be reduced.

It is sectional drawing which shows the injection nozzle part of the fuel injection valve by the 1st reference example of this invention. (A) is a top view which shows arrangement | positioning of the orifice of a 1st reference example, (B) is BB sectional drawing of (A), (C) is CC sectional drawing of (A). It is. It is a longitudinal cross-sectional view which shows the fuel injection valve of a 1st reference example. (A) is a characteristic diagram showing the relationship between DS / DH and SMD, (B) is a characteristic diagram showing the relationship between 1.5 d-h and SMD, and (C) is a graph showing the relationship between 4 d-H and SMD. It is a characteristic view which shows the relationship. It is a top view which shows the state which mounted the fuel injection valve of the 1st reference example in the intake pipe. FIG. 6 is a view in the direction of arrow VI in FIG. 5. It is a top view which shows arrangement | positioning of the orifice by the modification 1 of a 1st reference example. It is a top view which shows arrangement | positioning of the orifice by the modification 2 of a 1st reference example. It is a top view which shows arrangement | positioning of the orifice by the modification 3 of a 1st reference example. It is sectional drawing which shows the injection nozzle part of the fuel injection valve by the 2nd reference example of this invention. It is sectional drawing which shows the injection nozzle part of the fuel injection valve by 1st Example of this invention. It is sectional drawing which shows the injection nozzle part of the fuel injection valve by 2nd Example of this invention.

Explanation of symbols

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 Abutting part 30, 81 Nozzle body 31 Inner wall 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 Orifice 33, 83a, 87a, 91a Opposing surface 35, 85, 89, 93 Fuel chamber (fluid chamber)

Claims (8)

A valve body provided with a valve seat on the inner wall surface forming the fluid passage;
A valve member that opens and closes the fluid passage when the contact portion is separated from and seated on the valve seat ;
A fixed core;
A spool disposed on the outer periphery of the fixed core;
An electromagnetic coil wound around the outer periphery of the spool;
A movable core that is disposed so as to face the fixed core in the axial direction, is integrally connected to the valve member, and is attracted in the direction of the fixed core when an excitation current flows through the electromagnetic coil;
A fuel injection nozzle for a fuel supply device for a gasoline engine , comprising an orifice plate provided in the valve body on the fluid downstream side of the valve member, the orifice plate having a plurality of orifices penetrating in the plate thickness direction. hand,
A substantially disk-shaped fluid chamber is formed by 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 the inner wall surface. Forming,
The inner wall surface has a conical slope whose virtual extension line intersects the opposing surface of the orifice plate,
The orifice is formed inside an intersection line between the virtual extension line and the facing surface of the orifice plate,
The front 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,
The orifice plate is recessed to the fuel downstream side and joined to the tip of the valve body,
The fuel that has flowed into the fluid chamber along the inner wall surface collides with the orifice plate, and is injected from the orifice.
The orifice is arranged on a double concentric circle, and a line connecting the inner circumference side orifice and the central axis of the orifice plate is shifted in the circumferential direction from the outer circumference side orifice . A valve body provided with a valve seat on the inner wall surface forming the fluid passage;
A valve member that opens and closes the fluid passage when the contact portion is separated from and seated on the valve seat ;
A fixed core;
A spool disposed on the outer periphery of the fixed core;
An electromagnetic coil wound around the outer periphery of the spool;
A movable core that is disposed so as to face the fixed core in the axial direction, is integrally connected to the valve member, and is attracted in the direction of the fixed core when an excitation current flows through the electromagnetic coil;
A fuel injection nozzle for a fuel supply device for a gasoline engine , comprising an orifice plate provided in the valve body on the fluid downstream side of the valve member, the orifice plate having a plurality of orifices penetrating in the plate thickness direction. hand,
A substantially disk-shaped fluid chamber is formed by 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 the inner wall surface. Forming,
The front 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,
The orifice plate is recessed on the fuel downstream side and joined to the tip of the valve body,
The orifice is arranged on a double concentric circle, and a line connecting the inner circumference side orifice and the central axis of the orifice plate is shifted in the circumferential direction from the outer circumference side orifice . When the inclination angle of the orifice on the inner circumference of the double concentric circle with respect to the central axis of the valve member is θ1, and the inclination angle of the orifice on the outer circumference of the double concentric circle is θ2, θ1 <θ2. The fuel injection nozzle according to claim 1 or 2. The fuel injection according to any one of claims 1 to 3, wherein 0.5 <t / d <1.0, where t is a thickness of the orifice plate and d is a diameter of the orifice. nozzle. 5. The fuel injection nozzle according to claim 1, wherein d <0.25 mm, where d is a diameter of the orifice. The fuel injection according to any one of claims 1 to 5, wherein the orifice is inclined in a direction away from the central axis with respect to a central axis of the valve member as it goes downstream of the fuel. nozzle. The fuel injection nozzle according to claim 6, wherein the orifice is inclined by 15 ° or more in a direction away from the central axis of the valve member as it goes downstream of the fluid. A fuel injection device having the fuel injection nozzle according to any one of claims 1 to 7 is mounted on a downstream side of a throttle valve and upstream of a collecting portion of an intake pipe connected to each cylinder. Fuel supply device.

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