JP5955181B2 - 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 that injects fuel from a fuel injection hole in a state where a turning force is applied to the fuel in a swirl chamber.

Japanese Patent No. 3784748

When the valve is opened, fuel flows from the side hole at the end of the lateral passage (communication passage) communicating with the swirl chamber (swirl application chamber). When the fuel flows into the side holes, the fuel flows downward, and a region where the flow of the fuel stagnates occurs in the upper part of the lateral passage, which may hinder atomization of the fuel injected from the fuel injection holes.
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 smoothing the flow of fuel in the communication passage communicating with the swirl application chamber. .

In order to achieve the above object, in the present invention, the lateral passage extends laterally with respect to the axial direction of the communication passage at the opening side end of the valve seat member of the communication passage, and the depth is shallower than the depth of the communication passage. Formed.

  According to the present invention, the flow of fuel in the communication path can be made smooth.

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. 3 is an enlarged perspective view of a swirl chamber according to Embodiment 1. FIG. 2 is an enlarged plan view of a swirl chamber according to Embodiment 1. FIG. It is a figure which shows the state which attached the nozzle plate of Example 1 to the valve seat member. 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 a perspective view of the nozzle plate of a comparative example. It is an expansion perspective view of the swirl chamber of a comparative example. It is an enlarged plan view of a swirl chamber of a comparative example. It is a figure which shows the state which attached the nozzle plate of the comparative example to the valve seat member. It is a figure which shows the flow of the fuel at the time of valve opening of a comparative example. It is a figure which shows the analysis result of the flow of the fuel in the communicating path and swirl provision chamber of a comparative example. It is a figure which shows the fuel flow at the time of valve opening of Example 1 of Example 1. FIG. It is a figure which shows the analysis result of the flow of the fuel in the communicating path of Example 1, and a swirl provision chamber. It is a perspective view of the nozzle plate of another Example. It is a perspective view of the nozzle plate of another Example. It is a perspective view of the nozzle plate of another Example. It is a perspective view of the nozzle plate of another Example. It is a perspective view of the nozzle plate of another Example. It is a perspective view of the nozzle plate of another Example. It is a perspective view of the nozzle plate of another Example. It is a perspective view of the nozzle 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. Hereinafter, in FIG. 1, the upper side of the fuel injection valve 1 is referred to as one end and the lower side of the paper is referred to as the other end.
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. An O-ring 39 for connecting to the piping of the pump 47 is provided on the outer periphery of one end of the magnetic cylinder 2.
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. 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 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.
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 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 about 45 °, and the valve body 4 is seated on the valve seat 6 when the valve is closed.
A nozzle plate 8 is welded to the other end side of the valve seat member 7. The nozzle plate 8 is formed with six swirl chambers 41 that give a swirl (swirl flow) to the fuel, and fuel injection holes 44 through which the fuel swirled in the swirl chamber 41 is injected.

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.
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.

[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. FIG. 4 is an enlarged perspective view of the swirl chamber 41. FIG. 5 is an enlarged plan view of the swirl chamber 41. FIG. 6 is a view showing a state in which the nozzle plate 8 is attached to the valve seat member 7. The configuration of the nozzle plate 8 will be described with reference to FIGS.
A swirl chamber 41 is formed on one side surface of the nozzle plate 8. Six swirl chambers 41 are formed, each including a lateral passage 42, a communication passage 45, and a swirl imparting chamber 46.
The communication path 45 is a groove formed radially with respect to the nozzle plate 8. A swirl application chamber 46 is formed at the tip of the communication path 45, and the communication path 45 is connected in a tangential direction of the swirl application chamber 46. . The swirl imparting chamber 46 is formed in a bottomed concave shape having an inner side surface and a bottom portion, and is formed in a spiral shape (swirl shape, vortex shape) when the inner side surface is viewed from the axial direction of the nozzle plate 8. The communication path 45 and the swirl application chamber 46 are formed at the same depth. A fuel injection hole 44 that is a through hole is formed in the bottom of the swirl application chamber 46.
A lateral passage 42 extending in the lateral direction (circumferential direction of the nozzle plate 8) with respect to the axial direction of the communication passage 45 is connected to the base of the communication passage 45 (an end 45a opposite to the side connected to the swirl application chamber 46). doing. The lateral passage 42 is a groove that connects the bases of adjacent communication passages 45, and the depth thereof is formed to be shallower than the depth of the communication passage 45. Further, as shown in FIG. 6, the lateral passage 42 is disposed on the inner side of the inner periphery of the downstream opening 48 of the valve seat member 7, that is, on the center side of the nozzle plate 8.

[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 flows into the swirl application chamber 46 through each communication path 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.

(Fuel flow in the communication path)
The flow of fuel in the communication path 45 will be described. Before describing the flow of fuel in the communication path 45 of the first embodiment, the flow of fuel in the communication path 45 of the comparative example will be described. FIG. 8 is a perspective view of a nozzle plate 8 that is not provided with a lateral passage 42 as a comparative example. FIG. 9 is an enlarged perspective view of the swirl chamber 41 of the comparative example. FIG. 10 is an enlarged plan view of the swirl chamber 41 of the comparative example. FIG. 11 is a view showing a state in which the nozzle plate 8 of the comparative example is attached to the valve seat member 7. 12 is a view showing the flow of fuel when the valve is opened in the comparative example, and FIG. 12A is a view showing the flow of fuel from the valve body 4 and the valve seat member 7 to the fuel injection hole 44. 12 (b) is an enlarged view of the dotted line portion of FIG. 12 (a). FIG. 13 is a view showing the analysis result of the fuel flow in the communication passage 45 and the swirl imparting chamber 46, FIG. 13 (a) is the analysis result of the BB cross section of FIG. 10, and FIG. 13 (b) is the CC of FIG. FIG. 13C shows the analysis result of the cross section DD in FIG. 10. FIG. 13 shows that the darker the color (the higher the density of hatching and hatching), the slower the flow rate, and the lighter the color (the lower the density of the hatching and hatching), the faster the flow rate.
If not provided eyelet 42, the end of the communication passage 45 fuel (from the downstream opening 4 8 of the valve seat member 7) from above flows downwardly. Therefore, the flow of fuel is biased toward the bottom of the communication path 45 (portion indicated by (A) in FIG. 13), and a portion where the flow of fuel stagnates is formed at the upper portion of the communication path 45 (shown by (B) in FIG. portion). Therefore, the resistance of the fuel flow in the communication passage 45 is increased, and there is a possibility that the atomization of the fuel spray injected from the fuel injection hole 44 is hindered.
In order to smooth the flow of fuel in the communication path 45, a recess having a certain volume is formed at the end of the communication path 45 (the end of the communication path opposite to the swirl application chamber 46). It is conceivable to send the stored fuel to the communication path 45. However, if the recess is formed, the dead volume is increased. The dead volume refers to the volume of fuel remaining downstream from the valve body 4 when the fuel injection valve 1 is closed. When the pressure inside the intake manifold where the fuel injection valve 1 injects fuel becomes negative pressure, the remaining fuel boils under reduced pressure, the accuracy of fuel injection deteriorates, hydrocarbons increase due to incomplete combustion, and the on-off valve during low pulse control This causes deterioration of responsiveness and coarsening of spray particles in the initial stage of fuel injection. In the case of a high-pressure fuel injection valve that directly injects fuel into the engine cylinder, there is generally no negative volume effect because there is no negative pressure inside the cylinder. For this reason, it is desirable to reduce dead volume as much as possible.
Therefore, in the first embodiment, the lateral passage 42 is provided at the base 45 a of the communication passage 45. FIG. 14 is a view showing the flow of fuel when the valve is opened according to the first embodiment. FIG. 14A is a view showing the flow of fuel from the valve body 4 and the valve seat member 7 to the fuel injection hole 44. FIG. 14B is an enlarged view of the dotted line portion of FIG. 14A, and FIG. 14C is a view seen from the direction A shown in FIG. 14B. FIG. 15 is a view showing the analysis result of the fuel flow in the communication passage 45 and the swirl chamber 46, FIG. 15 (a) is the analysis result of the EE cross section of FIG. 5, and FIG. 15 (b) is the FF of FIG. FIG. 15C shows the analysis result of the cross section GG in FIG. 5. FIG. 15 shows that the darker the color, the slower the flow rate, and the lighter the color, the faster the flow rate.
14 and 15, when the lateral passage 42 is provided, the fuel flows from the top to the bottom at the end of the communication passage 45 as in the comparative example ((C) shown in FIG. 14). Then, a flow ((D) shown in FIG. 14) is generated from the lateral passage 42 in the lateral direction with respect to the axial direction of the communication passage 45. Therefore, the flow of the fuel from the top to the bottom is weakened, and the region where the fuel flows almost evenly at the top and bottom of the communication path 45 increases ((E) in FIG. 15A). Thereby, the efficiency of the fuel flow in the communication path 45 is improved, and atomization of the fuel spray can be promoted. Further, the fuel spray characteristics can be stabilized. Further, since the efficiency of the fuel flow in the communication path 45 is improved, the volume of the communication path 45 can be reduced, so that the dead volume can be reduced.
Further, the lateral passage 42 only needs to be able to create a fuel flow transverse to the axial direction of the communication passage 45 at the end of the communication passage 45. The depth of the shallow is formed. Thereby, an increase in dead volume can be suppressed.
Further, since the lateral passage 42 is formed so as to connect the bases 45a of the adjacent communication passages 45, the lateral passage 42 can be formed even in a portion where the communication passages 45 are densely packed. The lateral passage 42 can be extended in the circumferential direction of the nozzle plate 8 so as to be connected to the base 45a of the communication passage, or can be formed in an annular shape.

[effect]
The effects of the fuel injection valve 1 of the first embodiment are listed below.
(1) A valve body 4 provided so as to be able to open and close, a valve seat 6 on which the valve body 4 sits when the valve is closed, a valve seat member 7 having an opening on the downstream side, and a valve seat member 7 The nozzle plate 8 provided also in the downstream, the swirl application chamber 46 formed in the nozzle plate 8 for applying a turning force by turning the fuel inside, and the injection hole 44 formed at the bottom of the swirl application chamber 46 and penetrating to the outside And a communication passage 45 formed in the nozzle plate 8 and communicating with the swirl chamber 46 and the downstream opening 48 (opening) of the valve seat member 7. A lateral passage 42 extending in the lateral direction with respect to the axial direction of the communication passage is formed at the end of the member 7 on the downstream opening 48 side.
Therefore, the efficiency of fuel flow in the communication passage 45 is improved, and atomization of fuel spray can be promoted. Further, the fuel spray characteristics can be stabilized. Further, since the efficiency of the fuel flow in the communication path 45 is improved, the volume of the communication path 45 can be reduced, so that the dead volume can be reduced.
(2) The lateral passage 42 is connected to the adjacent communication passage 45.
Therefore, the lateral passage 42 can be formed even in a portion where the communication passage 45 is dense.

[Other Examples]
As described above, the present invention has been described based on the first embodiment. However, the specific configuration of each invention is not limited to the first embodiment, and even if there is a design change or the like without departing from the gist of the present invention. Are included in the present invention.

(Change in number of swirl rooms)
In the fuel injection valve 1 of the first embodiment, six swirl chambers 41 are formed, but the number of the swirl chambers 41 may be changed as appropriate according to the design of the fuel injection amount.
16 to 18 are perspective views of the nozzle plate 8. For example, two swirl chambers 41 may be formed as shown in FIG. 16, three swirl chambers 41 may be formed as shown in FIG. 17, or as shown in FIG. Four swirl chambers 41 may be formed.
(Changing the shape of the side passage)
In the fuel injection valve 1 of the first embodiment, the lateral passage 42 is formed so as to connect the adjacent communication passages 45, but it does not have to be formed so as to connect the adjacent communication passage 45 (or the root 45 a of the communication passage 45). good.
19 to 22 are perspective views of the nozzle plate. For example, as shown in FIGS. 19 to 22, the lateral passage 42 may not connect the adjacent communication passage 45. By not connecting the adjacent communication passages 45 to each other, that is, by dividing the lateral passages 42 and arranging them in the circumferential direction of the nozzle plate 8, the volume of the lateral passages 42 is relatively reduced and the dead volume is reduced. Can contribute.
Further, as shown in FIGS. 23 and 24, the lateral passage 42 may be a straight line instead of a curve.

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

Claims (2)

A valve body provided to be capable of opening and closing; and
A valve seat on which the valve body sits when the valve is closed, and a valve seat member having an opening on the downstream side;
A nozzle plate provided downstream of the valve seat member;
A swirl chamber that is formed in the nozzle plate and swirls fuel inside to impart a swirling force;
An injection hole formed at the bottom of the swirl application chamber and penetrating to the outside;
A communication path formed in the nozzle plate and communicating the swirl application chamber and the opening of the valve seat member;
In a fuel injection valve equipped with
A fuel injection valve characterized in that a lateral passage extending in a lateral direction with respect to the axial direction of the communication passage and having a depth shallower than the depth of the communication passage is formed at an end portion on the opening side of the communication passage. . The fuel injection valve according to claim 1, wherein
The fuel injection valve, wherein the lateral passage connects adjacent communication passages.

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