JPH08232811A - Fluid injection nozzle - Google Patents

Abstract

PURPOSE: To stabilize flow of fluid which is injected from an orifice, and control the direction of injecting fluid in a high level. CONSTITUTION: A needle which is housed being capable of reciprocating motion in a needle body, abuts and be separated on/from a part of a valve seat of a circular cone shaped swash surface. An orifice plate 52 which is brought in contact with the injection hole outlet surface of the needle body is provided with an orifice 56 which is penetrated in a plate thickness direction. The orifice 56 consists of a large diameter cylindrical surface 141 and a small diameter cylindrical surface 142 in order to control the direction of fuel flow. Since fuel is passed in a passage where an orifice effective opening port area is throttled on an orifice outlet side from the orifice inlet, the flow direction of fuel which is injected from the orifice 56 is decided. Therefore, directional control performance of fuel flow is improved. The degree that dispersion of fuel and splash-away are generated is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid injection nozzle, and more particularly, to an injection nozzle portion of an electromagnetic fuel injection valve for injecting and supplying fuel to an internal combustion engine for automobiles.

[0002]

2. Description of the Related Art Generally, a fuel injection valve used in an internal combustion engine has a valve member which is reciprocally slidably housed in a guide hole formed in an axial direction of a valve body and which is opened at a tip portion of the valve body. Is opened and closed by the vertical movement of the valve member. Therefore, the valve member is
The lift amount at the time of valve opening is precisely controlled so as to secure an appropriate fuel injection amount.

[0003]

In the case where the orifice plate is attached to the nozzle hole outlet formed in the nozzle body of the fuel injection valve, the fuel at the valve inlet portion is injected through the valve outlet portion during the valve opening operation. It is jetted through holes and orifices. The behavior of the fuel flow through the orifice plate will be described in detail with reference to FIG. An orifice 64 that connects the inlet surface 62 and the outlet surface 63 of the orifice plate 61 connects the inlet surface 62 and the outlet surface 63 at an angle slightly inclined from the direction orthogonal to the orifice plate surface. The fuel on the inlet surface 62 side of the orifice plate 61 is the orifice 6
Focusing on the shape of the fuel flow when passing through the nozzle 4 and the outlet surface 63, a fuel separation space 65 is generated on the inlet side of the inner wall of the orifice 64. The main flow of fuel injected from the orifice 64 is on the center side of the orifice 64, and a separation space portion 65 is formed radially outward from this center. On the outlet surface 63 side of the separation space portion 65, the fuel particles are scattered. The scale 67 and the scattering 68 are likely to occur. For this reason, the fuel injection shape becomes unstable, and it is difficult to perform advanced directional control.

An object of the present invention is to provide a fuel injection nozzle capable of stabilizing the flow of fluid injected from an orifice and highly controlling the direction of the fluid injected.

[0005]

In order to achieve the above object, a fluid injection nozzle according to claim 1 of the present invention comprises an injection valve body having a valve portion and an injection hole formed on the outlet side of the valve portion. A fluid injection nozzle, wherein an orifice plate having an orifice communicating with the injection hole is provided at the outlet of the injection hole, the inlet side of the orifice communicates with the injection hole, and the inlet effective opening area of the orifice is larger than the area. A structure is adopted in which the effective opening area of the outlet is set to be small.

According to a second aspect of the present invention, there is provided the fluid injection nozzle according to the first aspect, wherein the orifice has a step portion between the inlet side and the outlet side. In the fluid injection nozzle according to a third aspect of the present invention, in the configuration according to the first aspect, the orifice is formed by a tapered surface whose effective opening area is gradually reduced on the inlet side and the outlet side.

According to a fourth aspect of the present invention, there is provided the fluid injection nozzle according to the first aspect, wherein the orifice has a circular effective opening shape, the inlet side is a straight hole, and the outlet side is a throttle hole. To do. The fluid injection nozzle according to claim 5 is the structure according to claim 1, wherein the orifice is
The effective opening shape is a circle, and the inlet side is a large diameter straight hole and the outlet side is a small diameter straight hole.

According to a sixth aspect of the present invention, there is provided a fluid injection nozzle having an injection hole, a needle body having a conical slope surface formed on the inlet side of the injection hole, and an abutting portion capable of contacting a part of the conical slope surface. An orifice having a needle that can come into contact with and separate from a part of the conical slope, and a plate-shaped orifice that is attached to the nozzle hole outlet portion of the needle body and that communicates with the nozzle hole and penetrates in the plate thickness direction. And a plate.

[0009]

According to the fluid injection nozzle of the present invention, since the shape of the orifice is such that the cross-sectional area of the passage is narrowed from the inlet side of the orifice to the outlet side, the fuel passing from the injection hole of the injection valve body through the orifice of the orifice plate is The fuel is metered when it enters the orifice inlet from the volume side of the injection hole, and a separation space is generated around the fuel that is metered and flows out. The fuel passing through the center of the separation space passes through the passage whose orifice effective opening area is further narrowed on the orifice outlet side rather than the orifice inlet, so that the flow of the fuel injected from the orifice is directed. Therefore, the direction controllability of the fuel flow is improved. Therefore, the rate of occurrence of fuel scattering and scattering is reduced. For example, as can be seen by comparing the schematic diagram of the flow according to the example of the present invention shown in FIG. 5 with the schematic diagram of the flow according to the comparative example shown in FIG. 8, in the present invention, the fuel particles at the outlet side of the fuel flow The amount of dispersion and scattering is reduced, and fuel is directed and injected along the central axis direction of the orifice.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 4 show an embodiment in which the present invention is applied to a fuel injection valve of a fuel supply system for a gasoline engine.

First, a fuel injection valve as a fluid injection nozzle will be described with reference to FIG. As shown in FIG. 2, a fixed iron core 21, a spool 91, an electromagnetic coil 32, a coil mold 31, and metal plates 93, 94 as magnetic paths are provided inside a resin housing 11 of a fuel injection valve 10 as a fluid injection nozzle. And are integrally molded. The fixed iron core 21 is made of a ferromagnetic material and is provided inside the housing 11 so as to project from above the coil mold 31. A guide tube 29 is fixed to the inner wall of the fixed iron core 21.

The electromagnetic coil 32 is wound around the outer circumference of the resin spool 91, and then the spool 91 and the electromagnetic coil 32 are wound.
A coil mold 31 is resin-molded on the outer periphery of the coil mold 31 and the electromagnetic coil 32 is surrounded by the coil mold 31.
The coil mold 31 protects a cylindrical tubular portion 31a that protects the electromagnetic coil 32 and a lead wire that is electrically derived from the electromagnetic coil 32, and also retains a terminal 34, which will be described later. And a protruding portion 31b protruding upward from. And the coil mold 3
The spool 91 and the electromagnetic coil 32 are mounted on the outer periphery of the fixed iron core 21 in a state of being integrated by 1.

The two metal plates 93 and 94 are provided such that one upper end thereof contacts the outer circumference of the fixed iron core 21 and the other lower end thereof contacts the outer circumference of the magnetic pipe 23.
It is a member that forms a magnetic path that allows the magnetic flux to pass when electricity is applied to it, and is covered on the outer periphery of the tubular portion 31a so as to sandwich the tubular portion 31a from both sides. These two metal plates 93 and 9
4, the electromagnetic coil 32 is protected.

The housing 11 is located above the housing 11.
The connector portion 11a is provided so as to project from the outer wall of the connector. Then, the terminal 34 electrically connected to the electromagnetic coil 32 is embedded in the connector portion 11 a and the coil mold 31. The terminal 34 is connected to an electronic control unit (not shown) via a wire harness.

One end of the compression coil spring 28 is in contact with the upper end surface of the needle 25 fixed to the movable iron core 22 by welding, and the other end of the compression coil spring 28 is in contact with the bottom of the guide tube 29. The compression coil spring 28 urges the movable iron core 22 and the needle 25 downward in FIG. 1, so that the seat portion 42 of the needle 25 is seated on the valve seat 263 of the needle body 26. When an exciting current flows from the terminal 34 through the lead wire to the electromagnetic coil 32 by an electronic control unit (not shown), the needle 25 and the movable iron core 22
Is attracted toward the fixed iron core 21 against the biasing force of the compression coil spring 28.

The non-magnetic pipe 24 is connected to the lower portion of the fixed iron core 21. Then, one end 2 is formed below the fixed core 21 so as to partially project from the lower end of the fixed core 21.
4a is connected. Further, the lower end of the other end 24b of the non-magnetic pipe 24 is connected to the small diameter portion 23b of the magnetic pipe 23 made of a magnetic material and formed in a stepped pipe shape. The other end 2 of the non-magnetic pipe 24
4b serves as a guide for the movable iron core 22.

Next, in the inner space of the non-magnetic pipe 24 and the magnetic pipe 23, a movable iron core 22 made of a magnetic material and formed in a cylindrical shape is provided. The outer diameter of the movable iron core 22 is set to be slightly smaller than the inner diameter of the other end 24b of the non-magnetic pipe 24.
4 is slidably supported. The upper end surface of the movable iron core 22 is provided so as to face the lower end surface of the fixed iron core 21 with a predetermined gap.

A collar-shaped joint 43 is formed on the needle 25.
Are formed. Then, the joint portion 43 and the movable iron core 22
Are laser-welded, and the needle 25 and the movable iron core 22 are integrally connected. A plurality of grooves as fuel passages are formed on the outer periphery of the joint portion 43. A filter 33 is provided above the fixed iron core 21 to remove foreign matters such as dust in the fuel that is pressure-fed 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 iron core 21 through the filter 33 flows from the guide tube 29 to the joint portion 4 of the needle 25.
3 and the knurled groove formed in the sliding portion 41 of the needle 25, and the seat portion at the tip of the needle 25 ( Abutting part) 251 and valve seat 26
3 to the valve portion, and from this valve portion to the cylindrical surface 264 forming the injection hole.

Next, the structure of the discharge portion 50 of the fuel injection valve 10 will be described with reference to FIG. A needle body 26 is inserted into the large diameter portion 23a of the magnetic pipe 23 via a hollow disk-shaped spacer 27 and laser-welded. The thickness of the spacer 27 is adjusted so that the air gap between the fixed iron core 21 and the movable iron core 22 shown in FIG. 2 is maintained at a predetermined value. On the inner wall of the needle body 26, the cylindrical surface 261 on which the sliding portion 41 of the needle 25 slides, and the valve seat 2 on which the conical seat portion 251 of the needle 25 sits
And 63 are formed. Furthermore, the needle body 26
An injection hole 264 is formed at the center of the bottom of the.

A flange 36 is formed on the needle 25 so as to face the lower end surface of the spacer 27 accommodated in the inner wall of the large diameter portion 23a of the magnetic pipe 23 with a predetermined gap. The flange 36 is formed on the side of the seat portion 42 formed at the tip of the needle 25 in the entire length of the needle 25, and the needle body 2 is formed below the flange 36.
Sliding part 4 which is slidable on the cylindrical surface 26a formed on 6.
1 is formed.

Then, the injection hole 264 of the needle body 26
A flow control mechanism 51 is provided at the outlet of the. This flow control mechanism 51, as shown in FIGS. 1, 3 and 4,
The needle 25, the needle body 26, and the orifice plate 52 are configured by the shapes, positions, combinations thereof, and the like.

Each of these features will be described below in sequence. (1) Needle 25 As shown in FIG. 3, the needle 25 has a solid cylindrical surface 250, a sloped surface 253, a sloped surface 254, and a spherical surface 25 at its tip.
5 is formed. Each of these faces 250, 253, 2
54 and 255 are formed so that the boundary line is circular, and the annular line at the boundary between the solid cylindrical surface 250 and the inclined surface 253 serves as the contact portion (sheet portion) 251. FIG. 3 shows a valve closed state, and in this valve closed state, the contact portion 251 and the valve seat 263 are.
And are contact points, and the aggregate of these contact points is an annular line.

(2) Needle body 26 The needle body 26 is composed of the cylindrical surface 261, the conical inclined surface 262 and the cylindrical surface 264 forming the injection hole 8 shown in FIG. 3, and the boundary lines between these surfaces 261, 262, 264. Has a circular shape. (3) Orifice plate 52 The orifice plate 52, which constitutes a part of the flow control mechanism 51, is made of, for example, stainless steel, and is joined to the tip of the needle body 26 by welding, for example, full circumference welding, as shown in FIGS. 1 and 3. It This orifice plate 52 has four orifices 54, 55, 5 as shown in FIG.
6, 57 are formed so as to penetrate in the plate thickness direction.

Next, the features of the flow control mechanism 51 of the present invention will be sequentially described with reference to FIGS. 1, 3 and 4. Orifice (hole) shape As shown in FIG. 4, orifices 54, 55, 56, 57
In this case, four orifices 54, 55, 56, which are formed in the orifice plate 1, are provided.
One orifice 56 of 57 is shown in FIG. Here, the flow of fuel flowing through the orifice 56 will be described as a representative. The orifice 56 has a large-diameter cylindrical surface 1 on the inlet surface 2 side.
41 and a small diameter cylindrical surface 142 on the outlet surface 3 side.
A step 143 is formed in an annular shape between the large diameter cylindrical surface 141 and the small diameter cylindrical surface 142. The diameter of the cylindrical surface 141 is D ₁ , and the diameter of the cylindrical surface 142 is D ₂ (D ₁ > D ₂ ). According to this embodiment, when the needle 25 is lifted from the needle body 26, when the fuel flowing into the injection hole 8 along the tip of the needle passes from the inlet of the orifice 56 to the outlet of the orifice 56, a large-diameter cylindrical surface 141 is formed.
The flow of fuel is directed by the cylindrical surface 142 whose cross-sectional area (effective opening diameter) is smaller than that, and fuel injection with good directionality is performed. Therefore, the fuel spray having good directionality flows into the combustion chamber, and the amount of fuel adhering to the inner wall surface of the intake port is relatively reduced, resulting in a mixture that is easily spark-ignited. It has the effect of reducing exhaust gas.

Inclination Angle of Orifices (Hole) As shown in FIG. 4, four orifices 54, 55, 5
6 and 57 are formed in a stepped cylindrical shape, and the central axis of the cylinder is inclined by an inclination angle α with respect to the plate thickness direction line. As shown in FIG. 4, the inclination directions of the orifices 54, 55, 56, 57 are inclined in the directions of arrows 541, 551 shown in FIG. 4 with an inclination angle α from the inlet side to the outlet side. The orifices 57 and 56 are inclined in the directions of arrows 571 and 561 with an inclination angle α from the inlet side to the outlet side. Therefore, the orifices 54, 55, 56, 5
The flow of fuel ejected from 7 has a vector in the axial direction of the injection hole 8 and each vector of arrows 541, 551, 561, 571. This example is an example of two-way spraying.

Outer Circle Diameter of Offiris (Hole) As shown in FIG. 4, orifices 54, 55, 56, 57
Circumcircle diameter D of the entrance of ₁ Is the cylindrical surface 2 forming the injection hole 8.
64 needle body diameter D₂ Relation with (diameter of injection hole 8)
At the desk, D₁ ≤ 0.95D₂ Is set to.

When the orifice 54 is manufactured in the orifice plate 52, it is formed by electric discharge machining or press working. For example, the pin is pressed from the plate inlet face to the outlet face side by punching and punched. At this time, an irregular surface such as sagging of a hole portion may occur in the machining on the inlet surface side, and an irregular surface such as a fracture surface generally occurs on the outlet surface side. Therefore, even if an irregular irregular surface near the inlet face and the outlet face of the orifice 54 occurs, the irregular portion is set so as to come to the inner diameter side of the cylindrical surface 264. Since the circumscribed circle of the hole entrance comes radially inward from the cylindrical surface 264 forming these injection holes 8 by setting the above range, the orifice 54, via the injection hole 8 formed by the cylindrical surface 264, 55, 56, 57
The occurrence of turbulence in the flow of fuel passing through is suppressed, and accurate direction control of fuel is performed.

Opening Area of Injection Hole of Needle Body 26 Effective Opening Area of Injection Hole 8 of Needle Body 26 (Cylindrical Surface 2
64 of the opening _{area) S 2 (S 2 = πD} 2 2/4), when the sum S ₁ of the cross section effective opening area of the orifice 54, 55, 56 and 57, set to be 3S ₁ ≦ S ₂ . This is because the body opening area S ₂ is sufficiently larger than the sum S ₁ of the cross-sectional effective opening areas of the orifices 54, 55, 56 and 57, so that the fuel is supplied to the orifices 54 and
This is to alleviate the damper when passing through 5, 56 and 57. Due to this damper relaxation effect, the orifices 54, 5
The fuel injection direction control by 5, 56, 57 is surely performed, and the influence of the "unevenness" of the fuel flow can be suppressed.

Tip Shape of Needle 25 The tip shape of the needle 25 is a spherical surface 2 as shown in FIG.
55. In the present invention, it is also possible to make a curved surface shape that approximates a spherical surface without strictly pursuing the shape of the spherical surface 255. By forming a curved surface close to such a spherical surface, the needle 25 and the needle body 2
6 and 6 are separated from each other, the fuel flowing downward from the vicinity of the valve seat 263 in FIG.
4 and the conical surface 262, and the spherical surface 25
5 and the conical slope 262, a part of the fuel flows along the spherical surface 255 toward the central axis side of the needle 25. As a result, the flow of fuel (fluid) becomes smooth, and unbalanced or unbalanced flow of fuel can be reduced. Further, the spherical surface 255 has the orifices 54, 55, 5
This will have an insensitive effect on the deviation of the fuel jet injected through the nozzles 6, 57. Therefore, the direction of the fuel spray shape can be controlled more precisely.

Distance h from the Tip of the Needle to the Entrance Surface of the Orifice The distance (height h) from the spherical surface 255 as the tip of the needle to the entrance surface of the orifice plate 52 is 0.1 ≦ h
It is set to ≦ 0.5 (mm). If the height h is 0.1> h, the manufacturing process becomes difficult. Further, the fuel flow passing through the gap between the needle 25 and the needle body 26 has a great influence on the "bias" of the fuel flow passing through the orifices 54, 55, 56 and 57. For this reason,
0.1 ≦ h is set in order to facilitate the manufacturing process and reduce the influence of the deviation of the fuel flow.

On the contrary, when 0.5 <h, the fuel is likely to boil in the injection hole 8 having a large volume at high temperature, and the fuel flow rate is initialized when the injection pulse of the fuel injection valve 10 is low pulse. Will increase beyond the fuel flow rate corresponding to the pulse width of. Furthermore, the axial length of the cylindrical surface 264 forming the injection hole 8 becomes longer, and the needle body 26 becomes larger.

Seat Diameter of Needle 25 If the diameter of the contact portion (seat portion) 251 with which the needle 25 contacts the valve seat 263 is φ, φ ≦ 4 (mm). This is because if the seat diameter is made too large, it becomes difficult to manufacture the needle body 26, and the relative injection amount per unit time increases too much.

(Second Embodiment) A second embodiment of the present invention is shown in FIG.
Shown in The second embodiment shown in FIG. 6 is an example in which the inner wall of the orifice plate 52 is tapered so that the inner diameter of the orifice penetrating from the inlet surface 2 to the outlet surface 3 of the orifice plate 52 is gradually reduced.

As shown in FIG. 6, the orifice 150 is
The tapered surface 15 of the orifice plate 52 whose diameter gradually decreases from D ₁ to D ₂ from the inlet surface 2 to the outlet surface 3
One. The central axis of the tapered surface 151 has an inclination angle α for controlling the direction of the fuel. In the second embodiment, a separation portion of the fuel flow is generated on the inlet face 2 side of the orifice plate 52, but the inner diameter of the orifice is reduced toward the outlet face 3 side, and the fuel jet injected from the outlet face is directional. A good fuel flow injection form is obtained.

(Third Embodiment) FIG. 7 shows a third embodiment of the present invention.
Shown in The third embodiment shown in FIG. 7 is an example in which the orifice 160 penetrating the orifice plate 52 in the plate thickness direction is composed of a cylindrical surface and a tapered surface. The orifice 160 has a cylindrical surface 161 having a diameter D ₁ on the inlet surface side and a tapered surface 162 having an inner diameter gradually decreasing from the diameter D ₁ to the diameter D ₂ on the outlet surface 3 side. The central axis of the orifice 160 has an inclination angle α as in the first and second embodiments.

Also in the third embodiment, when the fuel on the inlet surface side of the orifice plate 52 enters the orifice 160, a separation space portion is generated, but this separation portion space portion becomes smaller due to the tapered surface 162 that is gradually narrowed, and the fuel is reduced. Is injected into the intake port in a directed manner. Therefore, in this embodiment, there is an effect that the fuel injection is performed with a high degree of direction control of the fuel jet passing through the injection hole and the orifice.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of an I portion shown in FIG. 3, showing the shape of an orifice according to the first embodiment of the present invention.

FIG. 2 is a sectional view of a fuel injection valve to which the present invention is applied.

FIG. 3 is a sectional view of a nozzle portion of the first embodiment.

FIG. 4 is a plan view of a part of the orifice plate on the inlet side as seen from the IV direction shown in FIG.

FIG. 5 is a schematic diagram showing how a fuel flow according to the first embodiment of the present invention flows.

FIG. 6 is a sectional view of an orifice according to a second embodiment of the present invention.

FIG. 7 is a sectional view of an orifice according to a third embodiment of the present invention.

FIG. 8 is a schematic diagram showing how a fuel flow of a comparative example flows.

[Explanation of symbols]

 1 Orifice Plate 2 Inlet Surface 3 Outlet Surface 8 Injection Hole 14 Orifice 25 Needle (Valve) 26 Needle Body (Injection Valve Main Body) 52 Orifice Plate 54, 55, 56, 57 Orifice 141 Large Diameter Cylindrical Surface 142 Small Diameter Cylindrical Surface 143 Stages Part 150 Orifice 151 Tapered surface 160 Orifice 161 Cylindrical surface 162 Tapered surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masanori Miyagawa 1-1 Chome, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (6)

[Claims] 1. A fluid injection nozzle having an injection valve body having a valve portion and an injection hole formed on the outlet side of the valve portion, the orifice having an orifice communicating with the injection hole at the outlet of the injection hole. A fluid injection nozzle, wherein a plate is provided, an inlet side of the orifice communicates with the injection hole, and an effective outlet opening area of the orifice is set smaller than an effective inlet opening area of the orifice. 2. The fluid injection nozzle according to claim 1, wherein the orifice has a step portion between the inlet side and the outlet side. 3. The fluid injection nozzle according to claim 1, wherein the orifice is formed by a tapered surface whose effective opening area is gradually reduced on the inlet side and the outlet side. 4. The fluid injection nozzle according to claim 1, wherein the orifice has a circular effective opening shape, a straight hole on the inlet side and a throttle hole on the outlet side. 5. The fluid injection nozzle according to claim 1, wherein the orifice has a circular effective opening shape, a large-diameter straight hole on the inlet side and a small-diameter straight hole on the outlet side. 6. A needle body having an injection hole and a conical slope surface formed on the inlet side of the injection hole, and an abutting portion capable of contacting a part of the conical slope surface, and a part of the conical slope surface. A needle that can be brought into contact with and separated from the needle body, and is attached to the nozzle hole outlet portion of the needle body in a plate shape,
An orifice plate having an orifice communicating with the injection hole and penetrating in the plate thickness direction.