JP5877768B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve used for fuel injection of an engine.

  As this type of technology, the technology described in Patent Document 1 below is disclosed. This publication discloses a fuel injection valve in which a swirl chamber and a fuel injection hole are formed in a passage plate, and the center of the fuel injection hole is offset by a predetermined distance from the center of the swirl chamber to the center side of the passage plate. .

Japanese Patent No. 3837389

In the fuel injection valve of Patent Document 1, the center of the fuel injection hole is offset from the center of the swirl chamber to the upstream side of the lateral passage. However, in order to avoid the spray interference and secure the distance between the injection holes, it is necessary to offset the fuel injection holes to the outside in the radial direction of the injector plate. If it is offset as it is, the liquid film distribution becomes uneven in the fuel injection holes, the particle size becomes large, and the fuel efficiency of the internal combustion engine may be reduced.
The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a fuel injection valve capable of promoting atomization while avoiding spray interference.

  In order to achieve the above object, in the present invention, when the fuel injection hole is drawn in a circle centered on a position offset from the center of the swirl application chamber when the swirl application chamber is viewed from the axial valve seat member side, The shape of the circle was distorted, and the center of gravity of the shape was located closer to the center of the swirl application chamber than the center of the circle.

  According to the present invention, atomization can be promoted while avoiding spray interference.

It is an axial sectional view of the fuel injection valve of Example 1. It is an expanded sectional view near the nozzle plate of the fuel injection valve of Example 1. 2 is a perspective view of a nozzle plate of Example 1. FIG. It is a top view of the swirl chamber and fuel injection hole of Example 1. It is a figure explaining the center of the swirl grant chamber of Example 1. FIG. It is a figure explaining the center of the swirl grant chamber of Example 1. FIG. It is the figure which described the flow of the fuel in the perspective view of the swirl chamber and fuel injection hole of Example 1. FIG. It is the figure which looked at the nozzle plate of Example 1 from the axial direction. It is a figure which shows the range of the spray of the liquid film state injected from the fuel injection hole of Example 1. FIG. It is a figure which shows the state arrange | positioned so that the center of the fuel injection hole which made the fuel injection hole circular when it sees from the valve-seat member side of Example 1 may correspond with the center of a swirl provision chamber. It is a figure which shows the state of the liquid film in the fuel-injection hole of Example 1. FIG. It is a top view of the swirl chamber and fuel injection hole of Example 2. It is a figure which shows the state of the liquid film in the fuel-injection hole of Example 2. FIG. It is a top view of the swirl chamber and fuel injection hole of other examples. It is a perspective view of the nozzle plate of another Example. It is a figure which shows the nozzle plate of another Example. It is a figure which shows the nozzle plate of another Example. It is a perspective view of a nozzle plate when three swirl chambers of another embodiment are formed. It is a perspective view of a nozzle plate when two swirl chambers of another embodiment are formed. It is an expanded sectional view near the nozzle plate of the fuel injection valve of other examples. It is a perspective view of the nozzle plate of another Example. It is an expanded sectional view near the nozzle plate of the fuel injection valve of other examples. It is a perspective view of the intermediate | middle plate of another Example. It is a perspective view of the nozzle plate of another Example.

[Example 1]
The fuel injection valve 1 according to the first embodiment will be described.
[Configuration of fuel injection valve]
FIG. 1 is an axial sectional view of the fuel injection valve 1. This fuel injection valve 1 is a so-called low-pressure fuel injection valve that is used in a gasoline engine for automobiles and injects fuel into an intake manifold.
The fuel injection valve 1 includes a magnetic cylinder 2, a core cylinder 3 accommodated in the magnetic cylinder 2, a valve element 4 slidable in the axial direction, and a valve shaft formed integrally with the valve element 4. 5, a valve seat member 7 having a valve seat 6 that is closed by the valve body 4 when the valve is closed, a nozzle plate 8 having a fuel injection hole through which fuel is injected when the valve is opened, and the valve body 4 is opened when energized It has an electromagnetic coil 9 that slides in the direction and a yoke 10 that induces magnetic flux lines.

The magnetic cylinder 2 is made of a metal pipe or the like formed of a magnetic metal material such as electromagnetic stainless steel, and is stepped as shown in FIG. 1 by using means such as deep drawing or pressing or grinding. It is integrally formed in a cylindrical shape. The magnetic cylinder 2 has a large-diameter portion 11 formed on one end side and a small-diameter portion 12 having a smaller diameter than the large-diameter portion 11 and formed on the other end side.
The small diameter portion 12 is formed with a thin portion 13 that is partially thinned. The small-diameter portion 12 includes a core tube housing portion 14 that houses the core tube body 3 on one end side from the thin wall portion 13, and a valve member 15 (valve body 4, valve shaft 5, valve seat member on the other end side from the thin wall portion 13 7) and is divided into a valve member accommodating portion 16 for accommodating. The thin portion 13 is formed so as to surround a gap portion between the core cylinder 3 and the valve shaft 5 in a state where the core cylinder 3 and the valve shaft 5 described later are accommodated in the magnetic cylinder 2. The thin wall portion 13 increases the magnetic resistance between the core tube housing portion 14 and the valve member housing portion 16, and magnetically blocks between the core tube housing portion 14 and the valve member housing portion 16.

The inner diameter of the large-diameter portion 11 constitutes a fuel passage 17 for sending fuel to the valve member 15, and a fuel filter 18 for filtering the fuel is provided at one end of the large-diameter portion 11. A pump 47 is connected to the fuel passage 17. The pump 47 is controlled by a pump control device 54.
The core cylinder 3 is formed in a cylindrical shape having a hollow portion 19 and is press-fitted into the core cylinder housing portion 14 of the magnetic cylinder 2. The hollow portion 19 accommodates a spring receiver 20 fixed by means such as press fitting. A fuel passage 43 penetrating in the axial direction is formed at the center of the spring receiver 20.
The outer shape of the valve body 4 is formed in a substantially spherical shape, and has a fuel passage surface 21 cut in parallel with the axial direction of the fuel injection valve 1 on the circumference. The valve shaft 5 has a large-diameter portion 22 and a small-diameter portion 23 whose outer shape is smaller than the large-diameter portion 22.

The valve body 4 is integrally fixed to the tip of the small diameter portion 23 by welding. In addition, the black semicircle and black triangle in a figure have shown the welding location. A spring insertion hole 24 is formed at the end of the large diameter portion 22. A spring seat 25 having a smaller diameter than the spring insertion hole 24 is formed at the bottom of the spring insertion hole 24, and a stepped spring receiving portion 26 is formed. A fuel passage hole 27 is formed at the end of the small diameter portion 23. The fuel passage hole 27 communicates with the spring insertion hole 24. A fuel outflow hole 28 penetrating the outer periphery of the small diameter portion 23 and the fuel passage hole 27 is formed.
The valve seat member 7 includes a substantially conical valve seat 6, a valve body holding hole 30 formed on the one end side from the valve seat 6 so as to be substantially the same as the diameter of the valve body 4, and one end opening side from the valve body holding hole 30. An upstream opening 31 having a larger diameter and a downstream opening 48 that opens to the other end of the valve seat 6 are formed.

The valve shaft 5 and the valve body 4 are accommodated in the magnetic cylinder 2 so as to be slidable in the axial direction. A coil spring 29 is provided between the spring receiver 26 and the spring receiver 20 of the valve shaft 5 to urge the valve shaft 5 and the valve body 4 to the other end side. The valve seat member 7 is inserted into the magnetic cylinder 2 and fixed to the magnetic cylinder 2 by welding. The valve seat 6 is formed so that the diameter decreases from the valve body holding hole 30 toward the downstream opening 48 at an angle of 45 °, and the valve body 4 is seated on the valve seat 6 when the valve is closed.
An electromagnetic coil 9 is inserted into the outer periphery of the core cylinder 3 of the magnetic cylinder 2. That is, the electromagnetic coil 9 is disposed on the outer periphery of the core cylinder 3. The electromagnetic coil 9 includes a bobbin 32 formed of a resin material and a coil 33 wound around the bobbin 32. The coil 33 is connected to the electromagnetic coil control device 55 via the connector pin 34.
The electromagnetic coil control device 55 energizes the coil 33 of the electromagnetic coil 9 to energize the fuel injection valve 1 in accordance with the timing of injecting fuel into the combustion chamber calculated based on the information from the crank angle sensor that detects the crank angle. Open the valve.

The yoke 10 has a hollow through-hole, and has a large-diameter portion 35 formed on one end opening side, a medium-diameter portion 36 formed with a smaller diameter than the large-diameter portion 35, and a diameter smaller than the medium-diameter portion 36. It is composed of a small diameter portion 37 formed on the end opening side. The small diameter portion 37 is fitted on the outer periphery of the valve member housing portion 16. An electromagnetic coil 9 is accommodated on the inner periphery of the medium diameter portion 36. A connecting core 38 is disposed on the inner periphery of the large diameter portion 35.
The connecting core 38 is formed in a substantially C shape by a magnetic metal material or the like. The yoke 10 is connected to the magnetic cylinder 2 at the large-diameter portion 35 via the small-diameter portion 37 and the connecting core 38, that is, magnetically connected to the magnetic cylinder 2 at both ends of the electromagnetic coil 9. It becomes. A protector 52 for holding the O-ring 40 for connecting the fuel injection valve 1 to the intake port of the engine and protecting the tip of the magnetic cylinder is attached to the tip of the yoke 10 on the other end side.

When power is supplied to the electromagnetic coil 9 through the connector pin 34, a magnetic field is generated, and the valve body 4 and the valve shaft 5 are opened against the biasing force of the coil spring 29 by the magnetic force of the magnetic field.
As shown in FIG. 1 of the fuel injection valve 1, most of the fuel injection valve 1 is covered with a resin cover 53. The portion covered with the resin cover 53 is from the portion excluding one end portion of the large-diameter portion 11 of the magnetic cylindrical body 2 to the electromagnetic coil 9 installation position of the small-diameter portion 12 to the medium-diameter portion 36 of the electromagnetic coil 9 and the yoke 10. Between the outer periphery of the connecting core 38 and the large-diameter portion 35, the outer periphery of the large-diameter portion 35, the outer periphery of the medium-diameter portion 36, and the outer periphery of the connector pin 34. The tip of the connector pin 34 is formed by opening a resin cover 53 so that the connector of the control unit can be inserted.
An O-ring 39 is provided on the outer periphery of one end of the magnetic cylinder 2, and an O-ring 40 is provided on the outer periphery of the small diameter portion 37 of the yoke 10.
A nozzle plate 8 is welded to the other end side of the valve seat member 7. The nozzle plate 8 is injected with a plurality of swirl chambers 41 that give a swirl (swirl flow) to the fuel, a central chamber 42 that distributes the fuel to each swirl chamber 41, and a fuel that has been swirled in the swirl chamber 41. A fuel injection hole 44 is formed.

[Configuration of nozzle plate]
FIG. 2 is an enlarged cross-sectional view of the vicinity of the nozzle plate 8 of the fuel injection valve 1. FIG. 3 is a perspective view of the nozzle plate 8. The configuration of the nozzle plate 8 will be described with reference to FIGS.
A swirl chamber 41 and a central chamber 42 are formed on one side surface of the nozzle plate 8. The central chamber 42 is formed in a circular concave shape with a bottom near the center of the nozzle plate 8. Three swirl chambers 41 are formed, each composed of a communication path 45 and a swirl imparting chamber 46. Each communication path 45 is connected near the center of the nozzle plate 8, and a central chamber 42 is formed at the connection portion. A swirl application chamber 46 is formed at the tip of the communication path 45, and the communication path 45 is connected in the tangential direction of the swirl application chamber 46. The swirl imparting chamber 46 is formed in a bottomed concave shape having an inner surface and a bottom portion, and its cross section is formed in a spiral shape. A fuel injection hole 44 that is a through hole is formed in the bottom of the swirl application chamber 46.

[Details of swirl chamber and fuel injection hole]
FIG. 4 is a plan view of the swirl chamber 41 and the fuel injection hole 44. 5 and 6 are views for explaining the center of the swirl application chamber 46. FIG. The configuration of the swirl chamber 41 and the fuel injection hole 44 will be described with reference to FIGS.
The swirl imparting chamber 46 has a spiral outer shape when viewed from the axial direction. The center Os of the swirl application chamber 46 is determined by the shape of the swirl application chamber 46, and the position of the center Os of the swirl application chamber 46 can be obtained as follows.
The first method is a method of obtaining from the spiral shape. As shown in FIG. 5, when the spiral shape is extended along the outer peripheral wall of the swirl application chamber 46, the tip of the extension curve becomes the center Os of the swirl application chamber 46. It becomes.
The shape of the fuel injection hole 44 viewed from the axial valve seat member 7 side (hereinafter referred to as the cross-sectional shape of the fuel injection hole 44) is a combination of a circle and an ellipse. In other words, the circle is distorted. It has a shape. And the shape is determined as follows. Referring to FIG. 4, a circle 44a having a center Oc at a position offset from the center Os of the swirl application chamber 46 is drawn in a state where the swirl application chamber 46 is viewed from the axial direction. The center Os side of the swirl imparting chamber 46 is circular with respect to the center Oc, and the side opposite to the center Os of the swirl imparting chamber 46 is elliptical with respect to the center Oc. At this time, the elliptical portion is provided such that the major axis of the ellipse is the diameter of the circle 44a, and the center of the ellipse coincides with the center Oc of the circle 44a. As a result, the center of gravity G of the cross-sectional shape of the fuel injection hole 44 is closer to the center Os side of the swirl application chamber 46 than the center Oc.

[Action]
(Fuel flow when the valve is closed)
When the coil 33 of the electromagnetic coil 9 is not energized, the valve shaft 5 is biased to the other end side by the coil spring 29 so that the valve body 4 is seated on the valve seat 6. For this reason, the space between the valve body 4 and the valve seat 6 is closed, so that fuel is not supplied to the nozzle plate 8 side.
(Fuel flow when the valve opens)
FIG. 7 is a perspective view of the swirl chamber 41 and the fuel injection hole 44 in which the flow of fuel is described.
When the coil 33 of the electromagnetic coil 9 is energized, the valve shaft 5 is pulled up to one end side by the electromagnetic force against the urging force of the coil spring 29. Therefore, the space between the valve body 4 and the valve seat 6 is released, and fuel is supplied to the nozzle plate 8 side.
The fuel supplied to the nozzle plate 8 first enters the central chamber 42, collides with the bottom of the central chamber 42, is converted from an axial flow to a radial flow, and flows into each communication passage 45. Since the communication passage 45 is connected in the tangential direction of the swirl application chamber 46, the fuel that has passed through the communication passage 45 swirls along the inner surface of the swirl application chamber 46.
A swirl force (swirl force) is imparted to the fuel in the swirl imparting chamber 46, and the fuel having the swirl force is injected while swirling along the side wall portion of the fuel injection hole 44. Therefore, the fuel injected from the fuel injection hole 44 is scattered in the tangential direction of the fuel injection hole 44. The fuel spray immediately after being injected from the fuel injection hole 44 is in a liquid film state in which the fuel forms a film on the substantially hollow conical spray surface by the edge portion of the opening of the fuel injection hole 44. Thereafter, the fuel spray that has been in the form of a film gradually starts to split and enters a liquid yarn state. Further, the splitting further proceeds, and the fuel is in a droplet state split into particles.

(Uniform thickness of the liquid film in the fuel injection hole)
FIG. 8 is a view of the nozzle plate 8 as viewed from the axial direction, and the hatched portion indicates the welding location. As described above, the nozzle plate 8 is welded to the valve seat member 7. Of course, the swirl imparting chamber 46 cannot be provided at the welding location. In order to suppress thermal deformation of the swirl imparting chamber 46, the swirl imparting chamber 46 cannot be provided close to the welding location. Therefore, the range in which the swirl application chamber 46 can be provided in the nozzle plate 8 is limited.
FIG. 9 is a diagram showing the range of spray in the liquid film state injected from the fuel injection hole 44. The distance between the two fuel injection holes 44 shown in FIG. 9B is the same as that shown in FIG. 9A. A state in which the fuel injection hole 44 is disposed at a position farther from the distance is shown.

As shown in FIG. 9A, when the distance between the fuel injection holes 44 is short, the fuel spray injected from the adjacent fuel injection holes 44 comes into contact in a liquid film state. When the fuel spray comes into contact with the liquid film, the liquid film becomes thick, and the particle size when the liquid is finally dropped becomes large. If the particle size is large, the fuel is not sufficiently vaporized in the intake port, which deteriorates the combustion efficiency of the internal combustion engine. Further, the combustion efficiency of the internal combustion engine deteriorates, so that there is a risk that the amount of nitrogen oxides and the like generated at the time of low temperature start increases. That is, it is desirable that the distance between the fuel injection holes 44 be as far as possible.
Considering the limitation when the swirl imparting chamber 46 is arranged in the nozzle plate 8 and the fact that the fuel injection hole 44 is arranged on the outer peripheral side of the nozzle plate 8, the center of the fuel injection hole 44 is the center of the swirl imparting chamber 46. In some cases, it is not possible to arrange them so as to coincide with the center.
For the following reason, the center of the fuel injection hole 44 may not be arranged so as to coincide with the center of the swirling chamber 46. FIG. 10 is a view showing a state where the center of the fuel injection hole 44 having a circular cross-sectional shape is aligned with the center of the swirl application chamber 46. In this case, as shown in FIG. 10, the fuel injection hole 44 and the outer peripheral wall of the swirl imparting chamber 46 may approach each other (position indicated by D in FIG. 10), and the fuel injection hole 44 may not be processed. Therefore, in order to secure the distance between the fuel injection hole 44 and the outer periphery of the swirl application chamber 46, the center of the fuel injection hole 44 needs to be offset from the center of the swirl application chamber 46.

When the center of the fuel injection hole 44 cannot be arranged so as to coincide with the center of the swirl application chamber 46 of the swirl application chamber 46, the following problem may occur.
FIG. 11 is a diagram showing a state of a liquid film in the fuel injection hole 44. FIG. 11A shows a circular cross-sectional shape of the fuel injection hole 44, and the swirl application of the swirl application chamber 46 at the center. FIG. 11B shows the state of the liquid film in the fuel injection hole 44 when it is disposed at a position offset from the center of the chamber 46, and FIG. 11B shows an elliptical part of the cross-sectional shape of the fuel injection hole 44 in FIG. The state of the liquid film in the fuel injection hole 44 when it is shaped is shown.
As shown in FIG. 11A, when the center of the fuel injection hole 44 is offset from the center of the swirl application chamber 46, the air layer is formed to be biased toward the center of the swirl application chamber 46. The thickness of the liquid film becomes uneven. The fuel spray injected from the portion where the liquid film in the fuel injection hole 44 is thick is less than the fuel spray injected from the portion where the liquid film in the fuel injection hole 44 is thin. The particle size increases. As described above, when the particle size of the fuel increases, there is a risk that the fuel efficiency of the internal combustion engine deteriorates and the amount of nitrogen oxides and the like generated at the time of low temperature start increases accordingly.
Therefore, in Example 1, the diameter of the fuel injection hole 44 corresponding to the portion where the liquid film in the fuel injection hole 44 becomes thicker is made smaller than the diameter of the circle 44a, and the circle 44a is set to have a distorted shape. Specifically, in the fuel injection hole 44, the periphery of the center Os side portion of the swirl imparting chamber 46 is circular with respect to the center Oc of the circle 44a, and the center Os of the swirl imparting chamber 46 is connected to the center Oc of the circle 44a. The circumference of the opposite side portion was an ellipse having a circular diameter as a major axis. In other words, the center of gravity G of the cross-sectional shape of the fuel injection hole 44 is set to be closer to the center Os side of the swirl imparting chamber 46 than the center Oc when the cross-sectional shape of the fuel injection hole 44 is circular.
Accordingly, as shown in FIG. 11B, the thickness of the liquid film can be made uniform as compared with the case where the cross-sectional shape of the fuel injection hole 44 is formed in a circular shape.

[effect]
The effects of the fuel injection valve 1 of the first embodiment are listed below.
(1) The valve body 4, the valve seat 6 on which the valve body 4 sits when the valve is closed are formed on one end side, and the other end side of the valve seat member 7 is formed to give the fuel a turning force A plurality of swirl imparting chambers 46, and nozzle plates 8 formed with fuel injection holes 44 that communicate with each swirl imparting chamber 46 and inject fuel to which a turning force is imparted. When a circle with the center Oc at the position offset from the center Os of the swirl chamber 46 is drawn as viewed from the axial direction of the chamber 46, the circle is distorted, and the center of gravity G of the circle is The swirl chamber 46 is positioned closer to the center Os side than the center Oc.
Thereby, the thickness of the liquid film in the fuel injection hole 44 can be made uniform.

(2) When the swirl chamber 46 is viewed from the axial direction, the fuel injection hole 44 is connected to the circle 44a with a part of the entire circumference as the circumference of the circle 44a and the rest as the center of the circle Oc. The circumference of the ellipse.
As a result, the inner peripheral shape of the fuel injection hole 44 can be smoothed, and the fuel can be injected while suppressing a decrease in the turning force of the fuel. Therefore, atomization of fuel spray can be promoted and the combustion efficiency of the internal combustion engine can be improved.
(3) When the swirl imparting chamber 46 is viewed from the axial direction, the fuel injection hole 44 is located on the opposite side of the center Os of the swirl imparting chamber 46 from the center Oc of the circle 44a, and the diameter of the circle 44a is the major axis. It was an ellipse.
Thus, when the fuel injection hole 44 is formed by a combination of a circle and an ellipse, the center of gravity G of the cross-sectional shape of the fuel injection hole 44 is disposed on the center Os side of the swirl application chamber 46 with respect to the center Oc of the circle 44a. It becomes possible. Therefore, the inner peripheral shape of the fuel injection hole 44 can be smoothed, and by making the thickness of the liquid film in the fuel injection hole 44 uniform, the atomization of the fuel spray can be promoted and the shape of the fuel spray can be changed. The combustion efficiency during internal combustion can be improved.

[Example 2]
In the fuel injection valve 1 according to the first embodiment, when the fuel injection hole 44 is viewed from the axial direction of the swirl application chamber 46, the opposite side of the center Os of the swirl application chamber 46 to the center Oc of the circle 44a An ellipse having a major axis of the diameter of In the fuel injection valve 1 of the second embodiment, the shape of the fuel injection hole 44 is different. Hereinafter, although the fuel injection valve 1 of Example 2 is demonstrated, about the structure similar to the fuel injection valve 1 of Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

[Details of swirl chamber and fuel injection hole]
FIG. 12 is a plan view of the swirl chamber 41 and the fuel injection hole 44. As in the first embodiment, the swirl imparting chamber 46 is formed in a spiral shape when viewed from the axial direction, and the center Os of the swirl imparting chamber 46 can be obtained by the same method as in the first embodiment. it can.
The cross-sectional shape of the fuel injection hole 44 is a combination of a circle and an ellipse, in other words, a shape in which the circle is distorted. And the shape is determined as follows. First, in a state where the swirl application chamber 46 is viewed from the axial direction, a circle 44a having a center Oc at a position offset from the center Os of the swirl application chamber 46 is drawn. Then, about half the circumference of the swirl chamber 46 opposite to the center Os with respect to the center Oc is circular, and about half the circumference of the swirl chamber 46 on the center Os side with respect to the center Oc is elliptical. At this time, the elliptical portion is provided such that the minor axis of the ellipse is the diameter of the circle 44a, and the center of the ellipse coincides with the center Oc of the circle 44a. As a result, the center of gravity G of the cross-sectional shape of the fuel injection hole 44 is closer to the center Os side of the swirl application chamber 46 than the center Oc.

[Action]
FIG. 13 is a view showing the state of the liquid film in the fuel injection hole 44. FIG. 13A shows the cross-sectional shape of the fuel injection hole 44 in a circular shape, the center of which is from the center of the swirl application chamber 46. FIG. 13B shows the state of the liquid film in the fuel injection hole 44 when the fuel injection hole 44 is disposed at an offset position. FIG. 13B shows a state in which a part of the cross-sectional shape of the fuel injection hole 44 in FIG. The state of the liquid film in the fuel injection hole 44 is shown.
As shown in FIG. 13 (a), when the center of the fuel injection hole 44 is offset from the center of the swirl application chamber 46, the air layer is formed biased toward the center side of the swirl application chamber 46. The thickness of the liquid film becomes uneven.
In Example 2, the diameter of the fuel injection hole 44 corresponding to the portion where the liquid film in the fuel injection hole 44 becomes thinner is made larger than the diameter of the circle 44a, and the circle 44a is set in a distorted shape. Specifically, in the fuel injection hole 44, the circumference of the portion opposite to the center Os of the swirl imparting chamber 46 with respect to the center Oc of the circle 44a is circular, and the swirl imparting chamber with respect to the center Oc of the circle 44a The circumference of the central Os side part of 46 was made into an elliptical shape with a circular diameter as a minor axis. In other words, the center of gravity G of the cross-sectional shape of the fuel injection hole 44 is set closer to the center side of the swirl imparting chamber 46 than the center Oc when the cross-sectional shape of the fuel injection hole 44 is circular.
As a result, as shown in FIG. 13B, the thickness of the liquid film can be made uniform as compared with the case where the cross-sectional shape of the fuel injection hole 44 is formed in a circular shape.

[effect]
The effects of the fuel injection valve 1 of Example 2 are listed below.
(4) When the swirl imparting chamber 46 is viewed from the axial direction, the fuel injection hole 44 has the center Os side of the swirl imparting chamber 46 with respect to the center Oc of the circle 44a and the diameter of the circle 44a as the minor axis. It was an ellipse.
Thus, when the fuel injection hole 44 is formed by a combination of a circle and an ellipse, the center of gravity G of the cross-sectional shape of the fuel injection hole 44 is disposed on the center Os side of the swirl application chamber 46 with respect to the center Oc of the circle 44a. It becomes possible. Therefore, the inner peripheral shape of the fuel injection hole 44 can be smoothed, and by making the thickness of the liquid film in the fuel injection hole 44 uniform, the atomization of the fuel spray can be promoted and the shape of the fuel spray can be changed. The combustion efficiency during internal combustion can be improved.

[Other Examples]
As mentioned above, although this invention has been demonstrated based on Example 1 and Example 2, the concrete structure of each invention is not limited to Example 1 and Example 2, and the range which does not deviate from the summary of invention. Such design changes are included in the present invention.
(Change of swirl chamber configuration)
In the fuel injection valves according to the first and second embodiments, the shape of the outer peripheral wall is formed in a spiral shape when the swirl imparting chamber 46 is viewed from the axial direction, but other shapes may be used.
FIG. 14 is a plan view of the swirl chamber 41 and the fuel injection hole 44. For example, as shown in FIGS. 14A and 14B, the shape of the outer peripheral wall of the swirl application chamber 46 may be circular when viewed from the axial direction.
(Change in number of swirl rooms)
In the fuel injection valve 1 of the first embodiment, three swirl chambers 41 are formed. However, the number of the swirl chambers 41 may be appropriately changed according to the design of the fuel injection amount.
FIG. 15 is a perspective view of the nozzle plate 8. For example, two swirl chambers 41 may be formed as shown in FIG.
FIG. 16 is a view showing the nozzle plate 8, FIG. 16A is a view of the nozzle plate 8 viewed from the axial direction, and FIG. 16B is a perspective view of the nozzle plate 8. For example, four swirl chambers 41 may be formed as shown in FIG.
FIG. 17 is a view showing the nozzle plate 8, FIG. 17A is a view of the nozzle plate 8 viewed from the axial direction, and FIG. 17B is a perspective view of the nozzle plate 8. For example, six swirl chambers 41 may be formed as shown in FIG.

(Changing the shape of the central chamber)
In the fuel injection valve 1 of the first embodiment, the central chamber 42 is formed in a circular concave shape, but the shape of the central chamber 42 may be different.
FIG. 18 is a perspective view of the nozzle plate 8 when three swirl chambers 41 are formed. FIG. 19 is a perspective view of the nozzle plate 8 when two swirl chambers 41 are formed. For example, as shown in FIGS. 18 and 19, the communication paths 45 may be directly connected, and the connection portion may be the central chamber 42.
(Change of nozzle plate)
In the fuel injection valve 1 of the first embodiment, the central chamber 42, the swirl chamber 41, and the fuel injection hole 44 are formed in the nozzle plate 8. However, all of these may not be formed in the nozzle plate 8.
20 is an enlarged cross-sectional view of the vicinity of the nozzle plate 8 of the fuel injection valve 1, and FIG. 21 is a perspective view of the nozzle plate 8. For example, as shown in FIGS. 20 and 21, the central chamber 42 and the swirl chamber 41 may be formed on the other end side of the valve seat member 7, and only the fuel injection hole 44 may be formed in the nozzle plate 8. .

(Addition of intermediate plate)
In the fuel injection valve 1 of the first embodiment, the central chamber 42, the swirl chamber 41, and the fuel injection hole 44 are formed in the nozzle plate 8. However, all of these may not be formed in the nozzle plate 8.
FIG. 22 is an enlarged cross-sectional view of the vicinity of the nozzle plate 8 of the fuel injection valve 1, FIG. 23 is a perspective view of the intermediate plate 50, and FIG. 24 is a perspective view of the nozzle plate 8. For example, as shown in FIGS. 22 to 24, a central chamber 42 and a swirl chamber 41 may be formed in the intermediate plate 50, and only the fuel injection hole 44 may be formed in the nozzle plate 8.

1 Fuel injection valve
4 Disc
6 Valve seat
7 Valve seat member
8 Nozzle plate
44 Fuel injection hole
45 passage
46 Swirl grant room
48 Downstream opening (opening)

Claims (4)

The disc,
A valve seat member formed on one end side of a valve seat on which the valve body sits when the valve is closed;
A plurality of swirl imparting chambers formed on the other end side of the valve seat member for imparting a turning force to the fuel;
A nozzle plate formed with fuel injection holes for injecting fuel to which the swirl force is applied in communication with each swirl application chamber;
Provided,
When the fuel injection hole has a circle centered on a position offset from the center of the swirl chamber when the swirl chamber is viewed from the axial direction, the circle is distorted, and the center of gravity of the shape Is located on the center side of the swirl chamber from the center of the circle. The fuel injection valve according to claim 1, wherein
When the swirl chamber is viewed from the axial direction, the fuel injection hole is an ellipse connected to the circle with a part of the entire circumference as the circumference of the circle and the rest as the center of the circle. A fuel injection valve characterized by having a circumference. The fuel injection valve according to claim 2,
The fuel injection hole, when the swirl imparting chamber is viewed from the axial direction, is the ellipse whose major axis is the diameter of the circle on the opposite side of the center of the swirl imparting chamber from the center of the circle. A fuel injection valve characterized by. The fuel injection valve according to claim 2,
The fuel injection hole, when the swirl application chamber is viewed from the axial direction, the center side of the swirl application chamber with respect to the center of the circle is the ellipse having the diameter of the circle as a short axis. A fuel injection valve.

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