JP2010133389A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve creating a fuel liquid film which can be easily atomized. <P>SOLUTION: A fuel impingement surface on which injected fuel from an injection hole impinges and the fuel liquid film is created is inclined to an axis of the injection hole, is a curved surface convex to a side on which the injected fuel impinges, and includes a flashing edge part at a downstream side of fuel. The fuel impingement surface is an outer circumference surface of a roughly cylindrical shape fuel impingement member having a diameter larger than the injection hole or an inner circumference surface of an opening surrounding the injection hole of a plate member, and is a developable surface such as a column surface, a cone surface, and a tangent surface. The fuel liquid film which can be easily atomized is stably created. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection valve, and more particularly to a fuel injection valve that can promote the atomization of fuel and is particularly suitable for an internal combustion engine such as an automobile engine.

  In a fuel injection valve for an internal combustion engine, the smaller the injected fuel particle size, the more the fuel evaporation is promoted, the amount of fuel adhering to the engine inner wall is reduced, the amount of unburned fuel is reduced, and the fuel efficiency is improved. This reduces the amount of harmful emissions.

  As a means for atomizing the injected fuel, the fuel is collided with a fuel collision member installed downstream of the nozzle hole, and the spray is diffused to atomize the fuel. Further, after the collision, the atomization is performed by forming a thin liquid film. Something that has been proposed has been proposed.

  For example, in the prior art described in Reference 1, a fuel injection valve including a fuel collision member having a wedge-shaped cross section at the downstream end of the nozzle hole is proposed. In this prior art, the fuel atomized by colliding the injected fuel with the fuel collision member is injected in two arbitrary directions.

  In the prior art described in Reference 2, the liquid film tends to be thinned in the central portion where the liquid film tends to be thick by forming the collision surface of the fuel collision member installed downstream of the nozzle hole portion in a W shape. It induces to the area, makes the formed liquid film thickness uniform, promotes atomization, and further suppresses the spread of spray.

  Further, in the prior art described in Reference 3, a fuel collision member having a width smaller than the diameter of the nozzle hole is provided downstream of the nozzle hole portion, and the injected fuel is appropriately formed into a liquid film by colliding with only a part of the fuel. Promotes the formation of fine particles.

JP-A-2-245470 Japanese Patent No. 3838089 JP 2008-31914 A (first page)

  In the fuel injection device of Patent Document 1, fuel spray is injected in two arbitrary directions by causing the injected fuel to collide with a wedge-shaped fuel collision member. In general, it is known that the liquid film formed after the fuel collides with the collision agent on the substantially flat surface is thicker in the vicinity of the center. If the film thickness formed after the fuel collision is non-uniform, the non-uniformity further develops due to shearing with air after injection, and the particle size finally formed becomes large. Therefore, it is necessary to form a thin and uniform liquid film for atomizing the fuel spray. In this prior art, there is no means for eliminating the non-uniformity of the liquid film thickness in the axial direction of the fuel collision member, and there is a problem that the particle size is prevented from becoming fine due to the non-uniform liquid film thickness. there were.

  Further, in the fuel injection device of Patent Document 2, the collision surface is formed in a W shape, and the region into which the liquid film both ends flows has a concave shape in which fuel is likely to accumulate due to its structure. It is known that both ends of the liquid film are disadvantageous for micronization because the liquid film thickness is originally thick and the speed is slow. However, in the related art, the liquid film thickness at both ends of the liquid film is affected by the recess. As a result, there is a problem in that the atomization at both ends of the spray is hindered.

  Moreover, in the fuel injection valve of patent document 3, only a part of injected fuel is made to collide with a fuel collision member. Immediately after the start of fuel injection or when the atmospheric pressure changes, the behavior of the injected fuel changes. At that time, the fuel that collides with the fuel collision member changes greatly, thereby promoting the atomization. There has been a problem that a fuel liquid film having a sufficient spread cannot be generated.

  An object of the present invention is to obtain a fuel injection valve capable of generating a fuel liquid film that promotes atomization of injected fuel.

  A fuel injection valve according to the present invention is a fuel injection valve that is disposed opposite to an injection hole and has a fuel collision surface that collides with injected fuel and generates a fuel liquid film. A fuel injection valve that is inclined with respect to the axis of the injection hole and has a convex curved surface on the side that collides with the injected fuel.

  According to the fuel injection valve of the present invention, the fuel collision surface is inclined with respect to the axis of the injection hole, and is a curved surface convex toward the side that collides with the injected fuel. Can produce a stable fuel liquid film.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view perpendicular to the operating axis of the fuel diffusion chamber of the fuel injection valve according to Embodiment 1 of the present invention. In the fuel injection valve 1, an electromagnetic coil 3, a fixed iron core 4, and a metal plate 5 constituting a magnetic passage are disposed in a resin housing 2 and are integrally formed. The electromagnetic coil 3 includes a resin bobbin 3 a, a coil 3 b wound around the outer periphery of the resin bobbin 3, and a terminal 6 provided for connection to the outside, and is integrally formed with the resin housing 2.

  An adjuster 8 for adjusting the load of the compression spring 7 is fixed inside the fixed iron core 4. One end of the metal plate 5 constituting the magnetic passage is fixed to the fixed iron core 4 by welding, and the other end is welded to the magnetic pipe 9 constituting the magnetic passage. A nonmagnetic pipe 11 is arranged between the fixed iron core 4 and the magnetic pipe 9 so that the movable iron core 10 arranged inside the magnetic pipe 9 can move up and down. And the magnetic pipe 9.

  A needle pipe 12 is fixed to one end of the movable iron core 10 by welding. One end of the needle pipe 12 on the side of the movable iron core 10 is in contact with the compression spring 7, and the other end is fixed with a ball 13 as a valve member by welding.

  FIG. 2 is an enlarged view of a portion surrounded by a circle A in FIG. 1, and FIG. 3 shows a front end portion of the fuel injection valve 1 shown in FIG. It is a schematic perspective view. In FIG. 2, the ball 13 is guided by a valve seat 14 disposed inside the magnetic pipe 9, and is disposed so as to be seated and separated from the seat portion 14 a of the valve seat 14. The outer peripheral portion of the ball 13 is processed into a pentagon, and a valve seat opening 14c is formed by a gap between the outer peripheral portion and the guide portion 14b and the seat portion 14a of the valve seat. An injection hole plate 17 in which an injection hole 18 and a fuel diffusion chamber 19 are formed is attached to the valve seat 14. The axis B of the nozzle hole 18 is inclined by an angle θ1 with respect to the axis C of the fuel injection valve 1.

  In the example shown in FIGS. 2 and 3, the fuel injection valve 1 is disposed so as to face the injection hole 18 provided in the injection hole plate 17, and is injected into a substantially cylindrical shape as shown in FIG. A fuel collision surface 22 that collides with the fuel 20 and changes the direction of the injected fuel 20 and diffuses to generate a fuel liquid film 21 is provided. The fuel collision surface 22 is a cylindrical surface provided on a cylindrical fuel collision member 23 attached to the nozzle hole plate 17 and having a diameter larger than that of the nozzle hole 18.

  The axis D of the cylindrical fuel collision member 23 is inclined with respect to the axis C of the fuel injection valve 1 at an angle θ2 larger than the axis B of the injection hole 18 and intersects with the axis B of the injection hole 18 at an angle θ3. is doing. In the illustrated example, the axes B, C, and D are in the same plane, so that the injected fuel 20 collides with the angle E3 on the ridgeline E at the position where the plane and the cylindrical surface of the fuel collision member 23 intersect. It collides with the fuel collision surface 22 of the member 23. The end face on the downstream side in the fuel flow direction, which is the tip of the cylindrical fuel collision member 23, is a plane 25 perpendicular to the axis D, and has a draining action with the fuel collision surface 22, which is a cylindrical surface. A portion 24 is formed.

  The fuel collision surface 22 is a cylindrical surface in the illustrated example, but may be a convex curved surface such as another developable surface or a woven surface (for example, a column surface, a weight surface, a tangential curved surface, etc.). The injected fuel 20 injected in a columnar shape collides with an angle (for example, θ3), is deflected and flows along the fuel collision surface 22, and a thin fuel liquid film 21 is formed away from the fuel collision surface 22 at the edge 24. This is very important. Thus, it can be said that the curved surface of the fuel collision surface 22 is inclined (for example, θ3) with respect to the axis B of the injection hole 18 and is a convex curved surface on the side that collides with the injected fuel 20.

  The angle at which the injected fuel 20 from the nozzle hole 18 collides with the fuel collision surface 22, that is, the angle θ 3 between the axis B of the nozzle hole 18 and the ridge line E of the fuel collision surface 22 indicates that the fuel after the collision is a fuel collision. The angle is such that the flow direction is changed without leaving the surface 22, the flow flows along the fuel collision surface 22, and the edge 24 having a draining action leaves the fuel collision surface 22. Such an angle is desirably changed according to various conditions such as the shape of the fuel collision surface 22 such as a curve and the fuel injection speed.

  Next, the operation of the fuel injection valve 1 in the present embodiment will be described. In FIG. 2, when the electromagnetic coil 3 is energized from the outside via the terminal 6, magnetic flux is generated in a magnetic path constituted by the fixed iron core 4, the metal plate 5, the magnetic pipe 9 and the movable iron core 10, and the movable iron core 10 is fixed. A needle pipe 12 that is attracted to the iron core 4 by a magnetic attractive force and is joined to and integrated with the movable iron core 10 and a ball 13 that is welded and fixed to the needle pipe 12 operate, and the seat portion 14a of the valve seat 14 and the ball 13 opens the valve seat opening 14c. Fuel flows into the main body of the fuel injection valve 1 from the upper part of FIG. 1 through a derivative pipe (not shown), passes through the filter 16, and the adjuster 8 and the compression spring 7 arranged in the fixed iron core 4, the movable iron core. 10, passes through the inside of the needle pipe 12, passes through the gap between the guide portion 14 b of the valve seat and the outer periphery of the ball 13, and is supplied from the valve seat opening 14 c to the fuel diffusion chamber 19, and is formed in the injection hole plate 17. The fuel is injected as injected fuel 20 from the nozzle hole 18.

  In FIG. 3, the fuel collision member 23 has a cylindrical shape, and is disposed at a position where an end projects in a direction crossing the axis B of the injection hole 18. The injected fuel 20 from the nozzle hole 18 collides with the fuel collision surface 22 in the vicinity of the end of the fuel collision member 23, flows along the curved surface of the cylinder, and then scatters from the edge 24 which is the end of the cylinder. Since the fuel collision surface 22 is curved in a convex shape, the fuel of the injected fuel 20 does not remain concentrated in the central portion, and the liquid has a substantially uniform thickness in the lateral direction along the curved surface of the fuel collision surface 22. As shown in FIG. 3, the fuel film dispersed as a film and separated from the fuel collision surface 22 has a uniform thin thickness of a semi-tubular shape or a half funnel shape whose diameter gradually increases in the flow direction. The fuel liquid film 21 is obtained, and good atomization characteristics can be obtained.

Further, the width of the fuel collision surface 22 is larger than that of the injection hole, and even if the behavior of the injected fuel changes and the collision position of the injected fuel 20 moves, the ratio of the collision fuel does not change greatly. Thus, the fuel liquid film 21 having a sufficient spread for promoting atomization can be generated regardless of conditions such as atmospheric pressure.
Embodiment 2. FIG.
4 is a schematic perspective view showing a fuel collision member 23 of a fuel injection valve according to Embodiment 2 of the present invention together with a fuel liquid film 21. In FIG. The fuel collision member 23 has a cylindrical shape whose tip is cut obliquely leaving the collision part side. That is, the front end portion of the fuel collision member 23 is formed by cutting along a plane substantially parallel to the main surface of the nozzle hole plate 17 (see FIGS. 2 and 3) provided with the nozzle holes 18. And has an elliptical end face 26 inclined at an angle of 90 ° -θ2. Other configurations are the same as those of the fuel injection valve described above.

According to this configuration, as compared with the fuel collision member 23 of the fuel injection valve of the first embodiment shown in FIGS. 1 to 3, the liquid film deflected and widened by the fuel collision surface 22 is separated from the fuel collision surface 22. The position of the portion 24 is on the more upstream side at the end in the width direction of the liquid film. Therefore, the velocity vector of the fuel when it reaches the edge 24 has a wider angle, and the fuel is scattered with a wider angle. Thereby, the spread of the fuel liquid film 21 is large and the thickness is thin, and better atomization characteristics are obtained.
Embodiment 3 FIG.
FIG. 5 is a schematic perspective view showing the fuel collision member 23 of the fuel injection valve according to the third embodiment of the present invention together with the fuel liquid film 21. The fuel collision member 23 is a plate-like member curved so as to have the fuel collision surface 22 on the outer peripheral surface. Further, the opening angle θ4 between the side edge portions 27 of the curved plate-shaped member is 0 ° or more and smaller than 180 °. In the example shown in the figure, it is a bowl-shaped member in which a tube having a circular cross section is divided roughly into two along the axis. Other configurations are the same as those of the fuel injection valve described above.

In this configuration, since the fuel collision member 23 is a plate-like member, the shape of the fuel collision surface 22 can be easily changed or adjusted by bending the plate-like member, and the above-described opening angle θ4 can be easily set. For this reason, for example, by moving the collision position of the injected fuel 20 with the fuel collision surface 22 from the tip of the fuel collision member 23 toward the root portion, the fuel liquid film spread on the fuel collision surface 22 is The fuel liquid film 21 spreads not only away from the edge 24 formed between the front end face of the fuel collision member 23 but also away from both side edges 27 of the bowl-like fuel collision member 23. Can be increased. If the opening angle θ4 between the side edges 27 of the curved plate-shaped member is 0 ° or more and less than 180 °, the formed fuel liquid film 21 also has an opening angle of 0 ° or more, and the downstream fuel The liquid films 21 do not collide with each other and bind to each other to prevent the formation of fine particles. When the opening angle is 180 ° or more, the fuel collision surface 22 is not a convex curved surface, and the collision, deflection, and deployment of the fuel collision surface 22 are impaired, and the thin fuel liquid film 21 cannot be generated.
Embodiment 4 FIG.
FIG. 6 is a schematic perspective view showing the fuel collision member 33 of the fuel injection valve according to the fourth embodiment of the present invention together with the fuel liquid film 21, and FIG. 7 shows the axis B and the ridge line E of the fuel collision surface 22 in FIG. It is sectional drawing along the plane containing. In this fuel injection valve, the fuel collision surface 22 is provided in the fuel collision member 33 which is a plate member disposed on the nozzle hole plate 17 in which the nozzle hole 18 is provided, and a hole portion surrounding the nozzle hole 18. Alternatively, it is a cylindrical surface provided on the edge of the opening 34.

  The opening 34 has a substantially C-shaped or round bracket shape in plan view, is provided in the fuel collision member 33, and has a cross-sectional shape that is the same inclined in the length direction (thickness direction of the fuel collision member 33). It has a fuel collision surface 22 which is a convex cylindrical surface having a ridge line E and an edge 35. The opening 34 also has a concave cylindrical surface facing the fuel collision surface 22 and having an outer peripheral edge 36. The ridgeline E of the fuel collision surface 22 and the axis B of the nozzle hole 18 intersect at an angle θ3. Accordingly, the injected fuel 20 from the nozzle hole 18 collides with the fuel collision surface 22 on the ridge line E, is deflected, and leaves the fuel collision surface 22 at the edge 35. Other configurations are the same as those described above.

According to this configuration, since the fuel collision member 33 having the fuel collision surface 22 is a single plate member having the opening 34 provided on the nozzle hole plate 17, it is easy to manufacture and assemble, and productivity is improved. It can be greatly improved. The shape of the opening 34 is arbitrary as long as the fuel collision surface 22 is provided. For example, the planar shape of the opening 34 can be changed, or the cross-sectional shape can be changed in the length direction.
Embodiment 5 FIG.
8 is a schematic cross-sectional view of a fuel collision member 37 of a fuel injection valve according to Embodiment 5 of the present invention, and FIG. 9 is a schematic perspective view of the fuel collision member 37 of FIG. The fuel collision member 37 is a single plate member having an opening 38, and the fuel collision surface 22 is provided on the inner peripheral surface of the opening 38 corresponding to the injection hole 18. In the illustrated example, there are four nozzle holes 18 of the nozzle hole plate 17, four fuel collision surfaces 22 are formed on the inner peripheral surface of one opening 38, and the axis B and the fuel collision surface of each nozzle hole 18. It arrange | positions so that 22 ridgelines E may cross | intersect. Other configurations are the same as those described above.

  Since the fuel collision member 37 is a single plate member having one opening 38, it can be easily manufactured and assembled, and the productivity can be greatly improved.

  The fuel injection valve illustrated and described above is merely an example, and various modifications can be made, and the features of each specific example can be used altogether or selectively combined. For example, the fuel collision surface 22 is a cylindrical surface provided on the fuel collision member 23, 33 or 37, but other convex surfaces such as a developable surface or a weave surface (for example, a column surface, a weight surface, a tangential curved surface, etc.). It may be a curved surface. Further, a plate member having a fuel collision surface 22 on the outer peripheral surface between the plurality of nozzle holes 18 may be disposed as the fuel collision member.

It is sectional drawing which shows the fuel injection valve which concerns on Embodiment 1 of this invention. FIG. 2 is an enlarged cross-sectional view of a portion surrounded by a circle A in FIG. 1. It is a schematic perspective view which shows the fuel collision member of the fuel injection valve concerning Embodiment 1 of this invention with a fuel liquid film. It is a schematic perspective view which shows the fuel collision member of the fuel injection valve concerning Embodiment 2 of this invention with a fuel liquid film. It is a schematic perspective view which shows the fuel collision member of the fuel injection valve concerning Embodiment 3 of this invention with a fuel liquid film. It is a schematic perspective view which shows the fuel collision member of the fuel injection valve concerning Embodiment 4 of this invention with a fuel liquid film. It is sectional drawing along the plane containing the axis line B and the ridgeline E of FIG. It is a schematic sectional drawing of the fuel collision member of the fuel injection valve which concerns on Embodiment 5 of this invention. It is a schematic perspective view of the fuel collision member of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fuel injection valve, 17 Injection hole plate, 18 Injection hole, 20 Injection fuel, 21 Fuel liquid film, 22 Fuel collision surface, 23, 33, 37 Fuel collision member, 24 Edge part, 26 End surface, 27 Both side edge part, 34 , 38 opening, B axis, θ4 opening angle.

Claims (8)

A fuel injection valve provided with a fuel collision surface disposed opposite to the injection hole and generating a fuel liquid film by colliding with the injected injected fuel,
The fuel injection valve characterized in that the fuel collision surface is inclined with respect to the axis of the nozzle hole and is a curved surface convex toward the side that collides with the injected fuel.   The fuel injection valve according to claim 1, wherein the fuel collision surface includes a draining edge on the downstream side of the injected fuel.   3. The fuel injection valve according to claim 1, wherein the fuel collision surface is a developable surface provided on a substantially cylindrical fuel collision member having a diameter larger than that of the nozzle hole.   4. The fuel injection valve according to claim 3, wherein the fuel collision member has an end face cut along a plane substantially parallel to the nozzle hole plate provided with the nozzle holes.   3. The fuel injection valve according to claim 1, wherein the fuel collision member is a plate-like member curved so as to have the fuel collision surface on an outer peripheral surface.   6. The fuel injection valve according to claim 5, wherein an opening angle between both side edges of the curved plate-shaped member is 0 ° or more and less than 180 °.   The fuel collision surface is provided on a fuel collision member which is a plate member disposed on the nozzle hole plate provided with the nozzle hole, and is a developable surface provided on an inner peripheral surface of an opening surrounding the nozzle hole. The fuel injection valve according to claim 1, wherein the fuel injection valve is a fuel injection valve.   The fuel injection valve according to claim 7, wherein the fuel collision surface is provided on the inner peripheral surface of the opening so as to correspond to the plurality of injection holes.

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