JP2001263206A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid fuel injection valve for an internal combustion engine such as a gasoline engine capable of efficiently promoting atomization of atomizing fuel. SOLUTION: In this solenoid fuel injection valve for the internal combustion engine such as the gasoline engine for flowing fuel flowed in from between a valve seat and a seat part toward a fuel inlet of an orifice 30 along a passage wall surface of an orifice plate 10 in a fuel passage 9 formed between a tip part of a needle valve and the passage wall surface of the orifice plate 10, two first and second curvature circle parts 31 and 32 having the curvature center on the axis of the orifice 30 and turning in the direction for returning to the upstream side to the fuel flowing direction of the fuel passage 9 are arranged on a hole wall surface up to a fuel outlet from the fuel inlet of the orifice 30. The first curvature circle part 31 is arranged on the axial side of the solenoid fuel injection valve, and the second curvature circle part 32 is arranged on the inverse side of the axial side of the solenoid fuel injection valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for injecting fuel into an intake pipe or a combustion chamber of an internal combustion engine, and more particularly, to a mechanism for promoting atomization of spray fuel injected near an intake valve of an internal combustion engine. The present invention relates to an electromagnetic fuel injection valve provided with:

[0002]

2. Description of the Related Art Conventionally, an electromagnetic fuel injection valve provided with a mechanism (orifice plate 106) for accelerating the atomization of spray fuel which is injected into a vicinity of an intake valve of an internal combustion engine such as a gasoline engine with good timing (for example, Japanese Unexamined Patent Publication No. No. 9-14090) has been proposed.

As shown in FIGS. 9 and 10, for example, such an electromagnetic fuel injection valve has an opening 1 at its center.
01, and a cylindrical valve body 103 having a valve seat 102 on the upstream side of the opening 101. The valve body 103 is slidably housed in the valve body 103, and has a valve seat 102 A needle valve 105 having a seat portion 104 in contact with the valve body 103 and an orifice plate 106 disposed on the distal end surface of the valve body 103 so as to close the opening 101. The orifice plate 106 has a round hole shape so as to be inclined from the fuel inlet to the fuel outlet by a predetermined inclination angle A (°) in a direction returning to the upstream side with respect to the fuel flow direction of the fuel passage 107. An injection hole (orifice) 108 is formed through.

[0004]

However, in a conventional electromagnetic fuel injection valve, a valve seat 102 is formed in a fuel passage 107 formed between a distal end surface of a needle valve 105 and a passage wall surface of an orifice plate 106. And seat part 10
4 flows into the orifice plate 106
After flowing along the passage wall surface toward the fuel inlet of the orifice 108, it flows into the orifice 108.

At this time, as shown in FIGS. 10A and 10B, a liquid column portion (109) is generated in the flow of the fuel in the orifice 108. The liquid column portion (10
The larger the volume of 9), the more the liquid column portion (109) of the fuel flow
Has a small surface area and a reduced contact area with air, which prevents fragmentation. This causes a problem that the effect of promoting the atomization of the spray fuel injected from the orifice 108 formed through the orifice plate 106 to the vicinity of the intake valve is reduced.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made to efficiently atomize spray fuel by promoting the division of a liquid column portion of a fuel flow generated in an injection hole formed through an injection hole plate. It is to provide a fuel injection valve which can promote the fuel injection.

[0007]

According to the first aspect of the present invention, a predetermined inclination from the fuel inlet of the injection hole toward the fuel outlet in a direction returning to the upstream side with respect to the fuel flow direction of the fuel passage. The injection hole is formed through the plate with the injection hole so as to be inclined at an angle, and the center of curvature on the center axis of the injection hole is formed on the hole wall from the fuel inlet to the fuel outlet of the injection hole. 2 facing the direction returning to the upstream side with respect to the direction
There are two curvature circles.

Accordingly, in the fuel passage formed between one end face of the needle valve and the passage wall surface of the plate with the injection hole, the fuel flowing from between the valve seat and the seat portion passes through the passage of the plate with the injection hole. After flowing toward the fuel inlet of the injection hole along the wall surface, it flows into the injection hole. At this time, a liquid column portion is generated in the flow of the fuel in the injection hole, and the liquid column portion is dispersed along one of the two curvature circle portions and injected from the fuel outlet of the injection hole. You. As a result, the surface area of the liquid column portion of the fuel flow in the injection hole increases, so that the contact area with air increases, and the division of the liquid column portion is promoted. Therefore, a decrease in the effect of promoting atomization of the spray fuel can be suppressed.

According to the second aspect of the present invention, a first curvature circle portion having a predetermined radius of curvature with the center of curvature being the center point of the curvature circle is provided on the center axis side of the fuel injection valve, and the fuel injection is performed. By providing a second curvature circle portion having a curvature radius substantially the same as the first curvature circle portion with the center of curvature being the center point of the curvature circle on the side opposite to the central axis side of the valve, the fuel in the injection hole is provided. The liquid column portion of the flow is dispersed along the first curvature circle portion of the two curvature circle portions and is injected from the fuel outlet of the injection hole.

According to the third aspect of the present invention, the plurality of injection holes are arranged on a single imaginary line about the center axis of the plate with the injection holes. According to the fourth aspect of the present invention, the plurality of injection holes are arranged on a double circle imaginary line centered on the central axis of the plate with the injection holes.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings. FIGS. 1 to 6 show a first embodiment of the present invention. FIG. 1 is a diagram showing the entire configuration of an electromagnetic fuel injection valve, and FIG. FIG. 2 is a diagram illustrating a main configuration of an injection valve.

The electronically controlled fuel injection system according to the present embodiment includes a sensor for detecting the operating state of a fuel supply system, an intake system, and an internal combustion engine, and an electronic control unit (EC) for integrally controlling them.
U) and the like. Among these, the fuel supply system pressurizes the fuel to a certain pressure by an electric fuel pump (not shown) and delivers the fuel to a delivery pipe (not shown).
This is a system in which fuel is sent to the electromagnetic fuel injection valve 1 through the controller and fuel can be injected at an optimum timing.

The electromagnetic fuel injection valve 1 has a function of promoting atomization of spray fuel which is injected with good timing near an intake valve (intake valve) (intake port) of an internal combustion engine (hereinafter referred to as an engine) such as a gasoline engine. (Orifice plate). The number of the electromagnetic fuel injection valves 1 corresponding to the number of cylinders of the engine is mounted on an intake manifold (intake pipe) for supplying air for combustion.

The electromagnetic fuel injection valve 1 includes a housing mold 2 assembled to a delivery pipe, and an electromagnetic coil (solenoid coil) 4 wound around an outer periphery of a resin coil bobbin 3 disposed in the housing mold 2.
A substantially cylindrical fixed core (stator) 5 fixed in the housing mold 2, a movable core (armature) 6 movable in the axial direction, and a valve body 7 provided on the distal end side of the housing mold 2. The needle valve 8 includes a needle valve 8 housed in the valve body 7 and an orifice plate 10 that forms a fuel passage 9 between one end surface (tip surface) of the needle valve 8 in the axial direction.

The housing mold 2 is integrally formed of a resin material. Inside the housing mold 2, a coil bobbin 3, a fixed iron core 5, and an external connection terminal (terminal) 11 are integrally formed. A resin mold 35 surrounding the electromagnetic coil 4 is integrally formed around the coil bobbin 3 and the electromagnetic coil 4.

A connector section 12 is provided above the housing mold 2 so as to protrude from the outer wall of the housing mold 2. And the electromagnetic coil 4
The external connection terminals 11 that are electrically connected to the connector are embedded in the connector section 12 and the resin mold 36. Also,
The external connection terminal 11 is connected to an ECU (not shown) via a wire harness.

The fixed iron core 5 is made of a ferromagnetic material, and is provided in the resin housing mold 2 so as to protrude above the upper end surface of the housing mold 2 in the figure. An axial fuel passage 13 is formed inside the fixed iron core 5. A substantially cylindrical adjusting pipe 15 having an axial hole 14 therein is provided on the inner peripheral surface of the fixed iron core 5.

The adjusting pipe 15 is displaced in the fixed iron core 5 in the axial direction, so that the coil spring 1 is displaced.
The set load (valve opening pressure) is set at 6 and is fixed to the inner peripheral surface of the fixed iron core 5 after setting. One end of a coil spring 16 is in contact with the tip surface of the adjusting pipe 15. This coil spring 16
Is in contact with the illustrated upper end surface of the needle valve 8 welded and fixed to the movable iron core 6.

The coil spring 16 is mounted on the movable iron core 6.
And by urging the needle valve 8 downward in the figure,
The seat portion 22 of the needle valve 8 is seated on the valve seat 21 of the valve body 7 (see FIG. 2). When an exciting current flows from the external connection terminal 11 to the electromagnetic coil 4 by the ECU, the movable iron core 6 and the needle valve 8 are attracted in the direction of the fixed iron core 5 against the urging force (spring force) of the coil spring 16. .

On one side of the fixed iron core 5 in the axial direction,
A non-magnetic pipe 17 and a magnetic pipe 18 are provided. The non-magnetic pipe 17 is made of a non-magnetic material and is formed in a substantially cylindrical shape. The non-magnetic pipe 17 is connected to the lower end of the fixed iron core 5 in the figure. In addition, magnetic pipe 1
Numeral 8 is made of a magnetic material and formed in a stepped pipe shape. The magnetic pipe 18 is connected to the illustrated lower end of the non-magnetic pipe 17. A movable iron core 6 made of a magnetic material and formed in a cylindrical shape is provided in the inner space of the non-magnetic pipe 17 and the magnetic pipe 18.

The valve body 7 is inserted into the inside of the magnetic pipe 18 through a hollow disk-shaped spacer 19 and is laser-welded. The thickness of the spacer 19 is
The air gap between the fixed iron core 5 and the movable iron core 6 is adjusted to be maintained at a predetermined value. Here, the housing mold 2, the electromagnetic coil 4, the fixed core 5, the movable core 6,
The non-magnetic pipe 17 and the magnetic pipe 18 constitute an electromagnetic actuator.

Next, the structure of the valve body 7 and the needle valve 8 of the present embodiment will be briefly described with reference to FIGS. The valve body 7 and the needle valve 8 are formed in a predetermined shape from a metal material such as SUS. A gap through which fuel passes is formed between the cylindrical surface 23 of the valve body 7 and the four chamfered portions formed on the sliding portion 24 of the needle valve 8. And
A valve portion is constituted by the valve seat 21 of the valve body 7 and the seat portion 22 at the tip of the needle valve 8.

The needle valve 8 corresponds to the valve body of the present invention, and has a joint 25 at the upper part in the figure. The joint 25 and the movable core 6 are laser-welded, whereby the movable core 6 and the needle valve 8 are integrally connected. A chamfer as a fuel passage is provided on the outer periphery of the joint 25. Further, when the movable core 6 is attracted to the fixed core 5 by generating a magnetomotive force in the electromagnetic coil 4, the needle valve 8 is lifted until the flange portion 26 comes into contact with the spacer 19. Here, the valve body of the electromagnetic fuel injection valve 1 is constituted by the valve body 7 and the orifice plate 10, and the valve body of the electromagnetic fuel injection valve 1 is constituted by the needle valve 8.

On the other hand, a filter 37 is mounted above the fuel passage 13 formed in the fixed iron core 5 in the figure.
The filter 37 is a foreign matter removing unit that removes foreign matter such as dust in the fuel that is pumped from the fuel tank by a fuel pump or the like and flows into the electromagnetic fuel injection valve 1.

Next, the orifice plate 10 of this embodiment is
The structure will be briefly described with reference to FIGS. Here, FIG. 3 is a diagram showing the passage wall surface of the orifice plate 10, and FIG. 4 is an enlarged view of the vicinity of the fuel inlet of the orifice plate 10.

The orifice plate 10 corresponds to the plate with injection holes according to the present invention. The orifice plate 10 closes a round hole-shaped opening 29 formed at the lower end surface (tip surface) of the valve body 7 in the figure. 7 is fixed by laser welding to the tip end surface. This orifice plate 10 is made of SU
It is made of a metal material such as S. The orifice plate 10 has a plurality of orifices (small holes) 30 for controlling the direction of the spray fuel and promoting atomization of the spray fuel.
Are formed.

These orifices 30 correspond to the injection holes of the present invention, and are formed by, for example, electric discharge machining or drilling, and are drawn on a single circle imaginary line centered on the center axis of the orifice plate 10. Are arranged. The plurality of orifices 30 are inclined from the fuel inlet of the orifice 30 to the fuel outlet by a predetermined inclination angle A (°) in a direction returning to the upstream side with respect to the fuel flow direction of the fuel passage 9. 10 is formed through. The central axis 33 of the orifice 30 is provided on the wall surface of the plurality of orifices 30 from the fuel inlet to the fuel outlet.
Two first and second curvature circle portions 31 and 32 each having an upper center of curvature and returning in the direction returning to the upstream side with respect to the fuel flow direction of the fuel passage 9 are provided.

The first curvature circle portion 31 is provided on the center axis side of the electromagnetic fuel injection valve 1 (in the direction of the injection valve center) between the two first and second curvature circle portions 31 and 32. The first curvature circle portion 31 has a predetermined radius of curvature with the center of curvature (C1) as the center point of the curvature circle. The second curvature circle portion 32
Is provided on the opposite side (seat direction) to the center axis side of the electromagnetic fuel injection valve 1 among the two first and second curvature circle portions 31 and 32. The second curvature circle portion 32 has a center of curvature (C
It has a predetermined radius of curvature with 2) as the center point of the curvature circle. The curvature radius of the first curvature circle portion 31 and the curvature radius of the second curvature circle portion 32 are the same radius (for example, the injection hole diameter φd / 2).

The shape of the orifice 30 is such that the amount of deviation between the center of curvature (C1) of the first circle of curvature 31 and the center of curvature (C2) of the second circle of curvature 32 is L (mm), and the second circle of curvature is When the radius of curvature of the portion 32 is R (φd / 2), 0 (m
m) <L <2R (mm) is satisfied. Also,
The inclination angle A (°) of the orifice 30 with respect to the thickness direction of the orifice plate 10 satisfies the relationship of 0 ° <A <90 °. Here, the electromagnetic fuel injection valve 1 of the present embodiment
In this example, the ratio between the plate thickness t (mm) and the injection hole diameter φd (mm) is set within a specific range in order to maintain a certain degree of atomization promoting performance. Here, 34 is the orifice 3
The liquid column generated in the flow of the fuel within 0 is shown.

[Operation of the First Embodiment] Next, the operation of the electromagnetic fuel injection valve 1 of the present embodiment will be briefly described with reference to FIGS.

When the electromagnetic coil 4 of the electromagnetic fuel injection valve 1 is energized by the ECU, the movable core 6 is attracted to the fixed core 5 against the urging force of the coil spring 16, and is joined to the movable core 6 at the joint 25. Is lifted until the flange portion 26 of the needle valve 8 abuts on the spacer 19. Then, the valve portion including the valve seat 21 of the valve body 7 and the seat portion 22 of the needle valve 8 is opened.

Thus, the fuel which is pressurized to a certain pressure by the fuel pump and flows into the fuel passage 13 formed in the fixed iron core 5 of the electromagnetic fuel injection valve 1 through the delivery pipe through the filter 37 through the delivery pipe is adjusted. It passes through the gap between the axial hole 14 formed in the sting pipe 15 and the chamfered portion formed at the joint 25 of the needle valve 8, and further slides between the cylindrical surface 23 of the valve body 7 and the needle valve 8. The fuel passes through a gap between the four chamfered portions formed in the moving portion 24 and reaches the fuel passage 9 from between the valve seat 21 of the valve body 7 and the seat portion 22 of the needle valve 8.

Then, the main flow of the fuel passing between the valve seat 21 and the seat portion 22 collides with the passage wall surface of the orifice plate 10 in the fuel passage 9 as shown in FIG. The flow is directed along the passage wall surface of the orifice plate 10 and toward the center axis of the electromagnetic fuel injection valve 1. Then, the main flow of the fuel flowing from the fuel passage 9 into the fuel inlet of the orifice 30 does not form a vortex around the fuel inlet of the orifice 30 as shown in FIG. Orifice 30 from the first
It flows in while bending toward the passage wall surface of the curvature circle portion 31.

At this time, as shown in FIGS. 6A and 6B, the flow of the fuel in the orifice 30 is changed to the liquid column portion (3).
4) occurs, but the liquid column portion (34) of the fuel flow is provided on the center axis side (in the direction of the injection valve center) of the electromagnetic fuel injection valve 1 of the two first and second curvature circle portions 31 and 32. The fuel gas is dispersed along the first curved circular portion 31 and injected from the fuel outlet of the orifice 30 to the vicinity of the intake valve of the engine with good timing.

[Effects of the First Embodiment] As described above, the electromagnetic fuel injection valve 1 of the present embodiment increases the surface area of the liquid column portion (34) of the fuel flow in the orifice 30 by increasing the surface area.
The contact area with air increases, and the orifice 30
Since the division of the liquid column portion (34) of the fuel flow in the inside is promoted, it can be used efficiently and extremely ideal atomization can be realized.

[Second Embodiment] FIGS. 7 and 8 show a second embodiment of the present invention. FIG. 7 shows the main structure of an electromagnetic fuel injection valve, and FIG. 8 shows an orifice plate. FIG.

A plurality of orifices 30 of the present embodiment are arranged on a double circle imaginary line centered on the central axis of the orifice plate 10. These orifices 3
0 is formed through the orifice plate 10 so as to be inclined from the fuel inlet to the fuel outlet by a predetermined inclination angle in a direction returning to the upstream side with respect to the fuel flow direction of the fuel passage 9.

In the same manner as in the first embodiment, the orifice 30 has a center of curvature on the central axis 33 of the orifice 30 on the hole wall surface from the fuel inlet to the fuel outlet of the plurality of orifices 30. Two first and second curvature circle portions 31 and 32 facing the opposite side (the sheet side) from the center axis side of 1 are provided, respectively. The plurality of orifices 30
Can be freely arranged within a range that does not reduce the effect of promoting atomization of the sprayed fuel.

[Modification] In this embodiment, an example has been described in which a fuel injection valve for an internal combustion engine such as an electromagnetic fuel injection valve (fuel injector) 1 is attached to an intake manifold of a gasoline engine. The valve may be attached to a cylinder of the engine, and the fuel injection valve may be attached to a combustion device such as a water heater or an oil stove.

In this embodiment, an example has been described in which the valve element such as the needle valve 8 is applied to the electromagnetic fuel injection valve 1 which reciprocates in the axial direction by an electromagnetic actuator. However, the valve element is mechanically moved in the axial direction. The present invention may be applied to a fuel injection valve that reciprocates. For example, the present invention may be applied to a fuel injection nozzle that opens when the fuel is supplied into the valve body and reaches a predetermined oil pressure.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an entire configuration of an electromagnetic fuel injection valve (first embodiment).

FIG. 2 is a sectional view showing a main configuration of an electromagnetic fuel injection valve (first embodiment).

FIG. 3 is a plan view showing a passage wall surface of an orifice plate (first embodiment).

FIG. 4A is an enlarged plan view of the vicinity of a fuel inlet of an orifice, and FIG. 4B is a cross-sectional view taken along line HH of FIG.
Example).

FIG. 5 is an I view of FIG. 4B (first embodiment).

FIG. 6A is a cross-sectional view showing a fuel passage and a fuel flow in an orifice, and FIG. 6B is an explanatory diagram showing a liquid column portion of the fuel flow in the orifice (first embodiment).

FIG. 7 is a sectional view showing a main configuration of an electromagnetic fuel injection valve (second embodiment).

FIG. 8 is a plan view showing a passage wall surface of an orifice plate (second embodiment).

FIG. 9 is a cross-sectional view showing a main configuration of an electromagnetic fuel injection valve (prior art).

FIG. 10A is a cross-sectional view illustrating a fuel flow in a fuel passage and an orifice, and FIG. 10B is an explanatory diagram illustrating a liquid column portion of the fuel flow in the orifice (prior art).

[Explanation of symbols]

 Reference Signs List 1 electromagnetic fuel injection valve 7 valve body 8 needle valve (valve element) 9 fuel passage 10 orifice plate (plate with injection hole) 21 valve seat 22 seat portion 29 opening of valve body 30 orifice (injection hole) 31 first curvature Circle part 32 Second curvature circle part 33 Center axis of orifice 34 Liquid column part of fuel flow in orifice

Claims (4)

[Claims] 1. A cylindrical valve body having an opening at a tip end and a valve seat upstream of the opening, slidably received in the valve body, and having an outer periphery at one end. A valve body having a seat portion abutting on the valve seat; and a plate with an injection hole disposed on a distal end surface of the valve body so as to close an opening of the valve body and having an injection hole for injecting fuel. Formed between one end of the valve element and the passage wall surface of the plate with the injection hole, and the fuel flowing from between the valve seat and the seat portion flows along the passage wall surface of the plate with the injection hole. A fuel passage having a fuel passage flowing toward a fuel inlet of the injection hole, wherein the injection hole is located upstream from the fuel inlet toward the fuel outlet with respect to the fuel flow direction of the fuel passage. Incline by a predetermined angle in the return direction The nozzle wall has a center of curvature on the center axis of the injection hole on the wall surface from the fuel inlet to the fuel outlet, and the fuel flows in the fuel passage. A fuel injection valve, comprising: two curved circular portions directed in a direction of returning to the upstream side with respect to the fuel injection valve. 2. The fuel injection valve according to claim 1, wherein the two curvature circle portions are provided on a center axis side of the fuel injection valve, and the predetermined curvature center is a center point of the curvature circle. A first curvature circular portion having a radius of curvature, and substantially the same as the first curvature circular portion provided on a side opposite to a center axis side of the fuel injection valve and having the curvature center as a center point of the curvature circle; A fuel injection valve comprising a second curvature circle having a radius of curvature. 3. The fuel injection valve according to claim 1, wherein a plurality of the injection holes are arranged on a single circle imaginary line centered on a central axis of the plate with the injection holes. A fuel injection valve characterized in that: 4. The fuel injection valve according to claim 1, wherein a plurality of the injection holes are arranged on a double circle imaginary line centered on a central axis of the plate with the injection holes. A fuel injection valve.