JP2007032283A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve capable of diffusing fuel introduced to an injection hole and mixing the same with air in the injection hole and accelerating atomization of fuel particle. <P>SOLUTION: This valve is provided with a valve seat 18 including an opening part 23 through which fuel passes from an upstream, a ball 17 capable of reciprocating in an axial direction in relation to the valve seat 17 and a plate member 20 provided in a downstream of the valve seat 18 and including an injection hole 1 injecting fuel to an outside. A part of inlet part of the injection hole 19 faces the opening part 23 and a remaining part is shut off by the valve seat 18. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel injection valve that atomizes and injects fuel.

  In recent years, exhaust gas regulations for automobiles and the like have been strengthened, and there has been a demand for reducing harmful substances emitted. Therefore, combustion is improved by improving atomization of fuel particles injected from the fuel injection valve.

A conventional fuel injection valve includes a plate member having a plurality of injection holes, a valve seat provided with a valve seat upstream of the injection holes, one cylindrical fuel passage provided in the valve seat, and one cylinder. The fuel cavity disposed between the shape fuel passage and the plate member having a plurality of nozzle holes, and a contact that is supported by the valve seat so as to be able to reciprocate and seat on the valve seat And a valve member that opens and closes the nozzle hole when the contact portion is separated from the valve seat and seated on the valve seat.
In the above configuration, the diameter of the nozzle holes arranged in the plate member is φd, the arrangement pitch diameter arranged in the plate member is φP, the diameter of the cylindrical fuel passage is φD1, and the axial depth of the fuel cavity is t When φD1 + φd <φP and t <φd, the fuel flow is disturbed, and the fuel ejected from the nozzle hole is atomized (see, for example, Patent Document 1).

JP 2002-39036 A

  In the conventional fuel injection valve, the entire area of the injection hole inlet faces the fuel cavity, and the cross-sectional area of the flow path from the injection hole inlet to the outlet is constant. When introduced, the fuel is not sufficiently diffused, and the fuel and the air inside the nozzle hole are not easily stirred. Therefore, there is a problem that the fuel particles cannot be sufficiently atomized.

  An object of the present invention is to solve the above-described problems. The object of the present invention is to diffuse the fuel introduced into the nozzle hole and stir it with the air inside the nozzle hole, thereby A fuel injection valve capable of promoting atomization is provided.

  A fuel injection valve according to the present invention is provided on a downstream side of a valve seat having a valve seat having an opening through which fuel from the upstream side passes, a valve member capable of reciprocating in the axial direction with respect to the valve seat, and And a plate member having an injection hole for injecting fuel to the outside, a part of the inlet part of the injection hole faces the opening part, and the remaining part is closed by the valve seat.

  According to the fuel injection valve of the present invention, the flow passage cross-sectional area rapidly increases immediately after the fuel is introduced into the nozzle hole from the opening by closing a part of the inlet part of the nozzle hole with the valve seat. The fuel is diffused and agitated with the air inside the nozzle hole, so that atomization of the fuel can be promoted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a partial cross-sectional view showing a fuel injection valve 1 according to Embodiment 1 of the present invention, FIG. 2 is an enlarged view of a main part of the valve device 4 shown in FIG. 1, and FIG. 3 is shown in FIG. It is a principal part enlarged view of the valve apparatus 4. FIG.
In the figure, the fuel injection valve 1 includes a resin housing 3 whose upstream side is covered with a filter 2 that removes foreign matters in the fuel, a valve device 4 provided at an end of the housing 3, and a valve device 4. And a solenoid device 5 driven by an electromagnetic attractive force.

  The solenoid device 5 includes a fixed iron core 6 that is a fixed side of the magnetic circuit, an electromagnetic coil 7 provided on the outer peripheral side of the fixed iron core 6, a metal plate 8 that forms the magnetic circuit, and a hollow cylinder that also forms the magnetic circuit. Shaped electromagnetic pipe 9, movable iron core 10 which is the movable side of the magnetic circuit, needle pipe 11 welded and fixed to the movable iron core 10, and abuts on the upstream side of the needle pipe 11 to press the needle pipe 11 downstream. And a adjuster 13 that is fixed inside the fixed iron core 6 and adjusts the load of the compression spring 12.

The electromagnetic coil 7 includes a resin bobbin 14, a coil 15 wound around the bobbin 14, and a terminal 16 for connection to the outside.
Here, the fixed iron core 6, the electromagnetic coil 7, and the metal plate 8 are integrally formed inside the housing 3. The metal plate 8 has one end welded to the fixed iron core 6 and the other end welded to the electromagnetic pipe 9.

The valve device 4 is welded to the downstream side of the needle pipe 11 and reciprocates by the solenoid device 5. The ball 17 is a valve member, and the opening is disposed inside the electromagnetic pipe 9 and through which fuel from the upstream side passes. And a plate member 20 provided with injection holes 19 for injecting fuel to the outside.
Here, the valve seat 18 and the plate member 20 are connected to each other by welding.

Further, the valve seat 18 includes a seat portion 21 that is a surface in contact with the ball 17, a guide portion 22 that guides the reciprocating movement of the ball 17 in the axial direction, an opening portion 23 through which fuel from the upstream side passes, And a fuel cavity 24 for rectifying the fuel.
Here, the fuel cavity 24 is formed by processing the downstream side of the opening 23. Further, the outer peripheral portion of the ball 17 is processed into a pentagon, and the fuel passes through the gap between the guide portion 22 and the ball 17.

In the plate member 20, when the intersection with the axis of the ball 17 is a center point, a plurality of nozzle holes 19 each having a center in a center circle, which is a circle having the same radius around the center point, are circumferential. In the direction.
Each nozzle hole 19 penetrates in the plate thickness direction at an arbitrary angle corresponding to the fuel injection direction.

Here, a part of the inlet part of the injection hole 19 faces the opening part 23, and the remaining part is closed by the fuel cavity 24 of the valve seat 18. That is, immediately after the fuel is introduced into the injection hole 19 from the fuel cavity 24, the flow path cross-sectional area is configured to increase rapidly.
When the inner diameter of the fuel cavity 24 is φD1, the diameter of the circumscribed circle of the injection hole 19 is φS, and the diameter of the center circle is φP, φD1, φS, and φP are expressed by the following equation (1). Set to range.

    φS> φD1> φP (1)

Hereinafter, the operation of the fuel injection valve 1 configured as described above will be described.
First, fuel is introduced into the fuel injection valve 1 main body via a derivative pipe (not shown), passes through the filter 2, the adjuster 13, the compression spring 12, and the needle pipe 11, and is stored in the valve device 4. Yes.

Subsequently, when an operation signal is sent to the fuel injection valve 1 from an engine control device (not shown), a current is passed through the coil 15 of the solenoid device 5 via the terminal 16 and a magnetic flux is generated in the coil 15. . The generated magnetic flux passes through a magnetic circuit composed of the fixed iron core 6, the metal plate 8, the electromagnetic pipe 9, and the movable iron core 10, and the movable iron core 10 is compressed by the electromagnetic attraction force generated along with the generation of the magnetic flux. It is attracted toward the fixed iron core 6 against the compressive force.
When the movable iron core 10 is sucked to the fixed iron core 6 side, the ball 17 connected to the movable iron core 10 via the needle pipe 11 is also moved to the fixed iron core 6 side, and the seat portion 21 of the valve seat 18 and the ball 17 are moved. A gap is formed between them.

  Further, when an operation stop signal is sent from the engine control device to the fuel injection valve 1, the energization of the current to the coil 15 of the solenoid device 5 is stopped, and the electromagnetic attractive force is also lost as the magnetic flux is lost. With the disappearance of the electromagnetic attractive force, the ball 17 is pressed downstream by the compression spring 12, and the gap between the ball 17 and the seat portion 21 is closed.

  When a gap is formed between the ball 17 and the seat portion 21, the fuel stored in the valve device 4 is introduced into the fuel cavity 24 through the opening 23 from this gap. The fuel introduced into the fuel cavity 24 spreads radially on the surface of the plate member 20 and is introduced into the injection hole 19.

Here, the inlet portion of the nozzle hole 19 is partially blocked by the fuel cavity 24 based on the relationship of the expression (1), and immediately after the fuel passes through the inlet portion, the flow passage cross-sectional area rapidly increases. Is configured to do.
Therefore, the fuel introduced into the nozzle hole 19 is diffused in the direction in which the cross-sectional area of the nozzle hole 19 increases, and is agitated with the air inside the nozzle hole 19 to be atomized.

  In addition, when the dimension of the inner diameter φD1 of the fuel cavity 24 is smaller than the dimension of the diameter φP of the center circle, there arises a problem that an influence of an assembly error generated when the valve seat 18 and the plate member 20 are welded is large. Therefore, φD1, φS, and φP are set in a range that satisfies the relationship of Expression (1).

  According to the fuel injection valve 1 according to Embodiment 1 of the present invention, the fuel cavity 24 closes a part of the inlet of the injection hole 19 so that the fuel is introduced into the injection hole 19 from the fuel cavity 24 immediately after the fuel is introduced. Since the cross-sectional area of the flow path rapidly increases, the fuel introduced into the injection hole 19 is diffused in the direction in which the cross-sectional area of the injection hole 19 increases, and is stirred with the air inside the injection hole 19 to produce fine fuel particles. Can be promoted.

Embodiment 2. FIG.
FIG. 4 is an enlarged view of a main part showing a fuel injection valve 1A according to Embodiment 2 of the present invention.
In the figure, the fuel cavity 24 shown in FIGS. 2 and 3 is eliminated. Further, assuming that the inner diameter of the opening 23 is φD2, the diameter of the circumscribed circle of the nozzle hole 19 is φS, and the diameter of the central circle is φP, φD2, φS, and φP are expressed by the following equation (2). Is set to a range.
Other configurations are the same as those in the first embodiment, and the description thereof is omitted.

    φS> φD2> φP (2)

Hereinafter, the operation of the fuel injection valve 1A having the above configuration will be described. Note that the description of the same operation as in the first embodiment is omitted.
A part of the fuel introduced into the opening 23 due to the formation of a gap between the ball 17 and the seat portion 21 is directly introduced into the injection hole 19 at the introduced speed, and the inner wall surface of the injection hole 19. Among them, it collides with the inner inner wall surface 26 which is the center point side of the plate member 20, that is, the inner side.

The fuel that has collided with the inner inner wall surface 26 is pressed against the inner inner wall surface 26 to generate a contracted flow, and is spread over the inner inner wall surface 26 to be thinned. By reducing the thickness of the fuel, the surface area in contact with the air inside the nozzle hole 19 is increased and atomized.
Further, the fuel that has not been directly introduced into the nozzle hole 19 is diffused in the direction in which the cross-sectional area of the nozzle hole 19 expands, and is agitated and atomized with the air inside the nozzle hole 19 as in the first embodiment. The

  According to the fuel injection valve 1A according to the second embodiment of the present invention, in addition to the effects shown in the first embodiment, the opening 23 is obtained by eliminating the fuel cavity 24 shown in FIGS. Since a part of the fuel introduced into the nozzle is directly introduced into the nozzle hole 19 at the introduced speed and collides with the inner inner wall surface 26, the fuel is spread and thinned at the inner inner wall surface 26. The surface area in contact with the internal air can be increased to further promote fuel atomization.

Embodiment 3 FIG.
FIG. 5 is an enlarged view of a main part showing a fuel injection valve 1B according to Embodiment 3 of the present invention.
In the drawing, the valve seat 18 has an acute angle between the seat portion 21 and a surface perpendicular to the axis of the ball 17, and is α ° on the downstream side of the contact portion 25 between the seat portion 21 and the ball 17. It is formed to be large.
Other configurations are the same as those in the second embodiment, and the description thereof is omitted.

Hereinafter, the operation of the fuel injection valve 1B having the above configuration will be described. The description of the same operation as that of the second embodiment is omitted.
Part of the fuel introduced into the opening 23 by forming a gap between the ball 17 and the seat portion 21 is directly introduced into the nozzle hole 19 at the introduced speed.
Here, the acute angle between the seat portion 21 and the surface perpendicular to the axis of the ball 17 is formed to be larger by α ° on the downstream side than the contact portion 25 between the seat portion 21 and the ball 17. Therefore, as compared with the second embodiment, a larger amount of fuel is directly introduced into the injection hole 19 and collides with the inner inner wall surface 26.

  According to the fuel injection valve 1B according to Embodiment 3 of the present invention, the acute angle between the seat portion 21 and the surface perpendicular to the axis of the ball 17 is the contact between the seat portion 21 and the ball 17. Since it is formed so as to be larger by α ° on the downstream side than the portion 25, a larger amount of fuel is directly introduced into the injection hole 19 and collides with the inner inner wall surface 26 as compared with the second embodiment. Fuel atomization can be promoted.

It is a fragmentary sectional view which shows the fuel injection valve which concerns on Embodiment 1 of this invention. It is a principal part enlarged view of the valve apparatus shown in FIG. It is a principal part enlarged view of the valve apparatus shown in FIG. It is a principal part enlarged view which shows the valve apparatus of the fuel injection valve which concerns on Embodiment 2 of this invention. It is a principal part enlarged view which shows the valve apparatus of the fuel injection valve which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection valve, 17 Ball (valve member), 18 Valve seat, 19 Injection hole, 20 Plate member, 21 Seat part, 23 Opening part, 24 Fuel cavity, 25 Contact part.

Claims (4)

A valve seat having an opening through which fuel from the upstream side passes;
A valve member capable of reciprocating in the axial direction with respect to the valve seat;
A plate member provided on the downstream side of the valve seat and having an injection hole for injecting the fuel to the outside,
A fuel injection valve characterized in that a part of the inlet of the injection hole faces the opening and the remaining part is closed by the valve seat. The plate member has a plurality of nozzle holes each having a center on a circumferential line of a center circle centered on the center point when an intersection point of the valve member with the axis is a center point of the plate member Is provided in the circumferential direction,
The dimension of the inner diameter φD of the opening is a value between a dimension of a diameter φS of a circumscribed circle connecting the nozzle holes and a dimension of a diameter φP of the central circle. Fuel injection valve.   In the valve seat, an acute angle angle formed by a surface on which the valve member abuts and a surface perpendicular to the axis is larger on the downstream side than the abutting portion between the valve seat and the valve member. The fuel injection valve according to claim 1, wherein the fuel injection valve is formed as follows.   The fuel injection valve according to claim 1 or 2, wherein a fuel cavity for rectifying fuel is formed on the downstream side of the opening.

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