JP2013194624A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve which can suppress deposition of fuel spray injected from the fuel injection valve on a wall of an intake port.SOLUTION: In fuel spray injected from a fuel injection hole 44, fuel spray toward a center direction of a nozzle plate 8 collides with a wall part 49 in a liquid film state, thereby changing an injection direction of the fuel spray downward. Thereafter, a fuel in the liquid film state is separated into liquid droplets of fine particles, and the fuel spray in the liquid droplet state is separated into two and spread within an intake port of an engine. As a result, the fuel spray can be set to be spread while avoiding a branch wall and deposition of the fuel on the branch wall is suppressed, thereby fuel economy can be enhanced.

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 that a passage plate in which a swirl chamber is formed and an injector plate in which a plurality of fuel injection holes that are open in the swirl chamber are welded to a valve seat member.

JP 2003-336562 A

In the technique described in Patent Document 1, since the fuel injected from each fuel injection hole spreads and overlaps in a conical shape, a fuel spray region integrated as a whole is formed. The fuel injection valve is provided in the intake port of the engine. However, since the intake port branches toward each valve, there is a possibility that fuel spray adheres to the wall at the branching position and fuel consumption deteriorates.
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 suppressing the fuel spray injected from the fuel injection valve from adhering to the wall of the intake port. It is to be.

  In order to achieve the above object, in the present invention, a convex wall portion is formed between the fuel injection holes on the other end surface of the nozzle plate.

  By this invention, it can suppress that fuel spray adheres to the wall of an intake port.

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. It is the front view and sectional drawing of a nozzle plate of Example 1. It is a perspective view of the nozzle plate of Example 1. It is an enlarged view of the swirl chamber and fuel injection hole part of Example 1. It is a figure which shows the shape of the fuel spray injected from the fuel injection hole of Example 1. FIG. It is a figure which shows the shape of the fuel spray injected from the conventional fuel injection hole. It is a figure which shows the spread of the fuel spray in the intake port of the conventional engine. It is a figure which shows the spread of the fuel spray in the intake port of the engine of Example 1. FIG. It is the front view and sectional drawing of a nozzle plate of Example 2. It is a perspective view of the nozzle plate of Example 2. 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. The fuel injection valve 1 is a so-called low-pressure fuel injection valve that is used in an automobile gasoline engine and injects fuel into an intake port.
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 44 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 valve 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 its diameter decreases from the valve body holding hole 30 toward the downstream opening 48, 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 step 35a of the large diameter part 35 via the small diameter part 37 and the connecting core 38, that is, magnetically connected to the magnetic cylinder 2 at both ends of the electromagnetic coil 9. Will be. 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.
Most of the outside 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.
A nozzle plate 8 is welded to the other end side of the valve seat member 7. The nozzle plate 8 is formed with a plurality of 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.

[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. 3 is a single view of the nozzle plate 8, FIG. 3 (a) shows a front view, and FIG. 3 (b) shows a cross-sectional view. FIG. 4 is a perspective view of the nozzle plate 8. The cross section of the nozzle plate 8 in FIG. 2 shows a state cut along the AA cross section line in FIG. FIG. 3B shows a state cut along the AA section line of FIG. The configuration of the nozzle plate 8 will be described with reference to FIGS. 2, 3, and 4.
A swirl chamber 41 is formed on one side surface of the nozzle plate 8. Two swirl chambers 41 are formed, each including a communication path 45 and a swirl imparting chamber 46. Each communication path 45 is connected near the center of 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 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.
A protruding wall 49 is formed on the other side surface of the nozzle plate 8. The wall portion 49 is provided between the two fuel injection holes 44. Although details will be described later, the height of the wall portion 49 is formed so as to collide with the wall portion 49 when the fuel injected into the fuel injection hole 44 is in the form of a liquid film. In other words, the fuel is formed at a height at which it collides with the wall portion 49 before it becomes droplets.

[Action]
(Fuel flow when the valve opens)
FIG. 5 is an enlarged view of the swirl chamber 41 and the fuel injection hole 44, and shows how fuel is injected from the fuel injection hole 44.
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 communication passage 45 in the nozzle plate 8 and collides with the bottom of the communication passage 45 to be converted from an axial flow to a radial flow. Flow into. 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 spreads conically in a thin liquid film state. Thereafter, the fuel in the liquid film state is separated into droplets that are atomized.
As a result, fuel vaporization can be promoted, and in particular, generation of nitrogen oxides and the like during low temperature starting can be reduced.

(Fuel spray shape)
6A and 6B are views showing the shape of the fuel spray injected from the fuel injection hole 44. FIG. 6A is a side view of the fuel spray, and FIG. 6B is a cross section of the droplet fuel spray. FIG.
Of the fuel spray injected from the fuel injection hole 44, the fuel spray directed toward the center of the nozzle plate 8 collides with the wall portion 49 in a liquid film state. Therefore, the fuel spray injection direction is changed downward. Thereafter, the fuel in the liquid film state is separated into droplets that are atomized. Therefore, the fuel spray in the form of droplets is separated into two shapes and spreads in the intake port of the engine.

(Inhibition of fuel adhesion to the intake port wall)
FIG. 7 is a view showing the shape of the fuel spray injected from the fuel injection hole 44 when the wall portion 49 is not provided on the conventional nozzle plate 8, and FIG. 7 (a) is a view of the fuel spray seen from the side. FIG. 7B is a cross-sectional view of droplet fuel spray.
The fuel spray injected from the fuel injection hole 44 spreads in the center direction of the nozzle plate 8 because there is no wall portion 49. Therefore, the fuel sprays injected from the fuel injection holes 44 spread in a conical shape, and the fuel sprays overlap to form a fuel spray region that is integrated as a whole.
FIG. 8 is a view showing the spread of fuel spray in the intake port 50 of the engine injected from the fuel injection hole 44 when the wall portion 49 is not provided in the conventional nozzle plate 8. The tip of the intake port 50 branches toward each valve 51, and a branch wall 50a is formed. When the wall portion 49 is not provided on the nozzle plate 8, the fuel spray region is integrally formed, so that a large amount of fuel adheres to the branch wall 50a. If the fuel adheres to the branch wall 50a, the fuel is vaporized before passing through the valve 51, and the fuel efficiency cannot be improved.

Therefore, in the fuel injection valve 1 of the first embodiment, a convex wall portion 49 is formed between the two fuel injection holes 44 on the surface on the other end side of the nozzle plate 8. Therefore, the fuel spray can be divided into two parts and spread in the intake port 50 of the engine. FIG. 9 is a view showing the spread of fuel spray in the intake port 50 of the engine. By providing the wall portion 49 on the nozzle plate 8, two fuel spray regions are formed separately, so that the fuel spray can be set so as to spread away from the branch wall 50a. For this reason, it is possible to suppress the fuel from adhering to the branch wall 50a, and to improve fuel efficiency.
In the fuel injection valve 1 of the first embodiment, the fuel and the wall 49 collide when the fuel injected from the fuel injection hole 44 is in the form of a liquid film. When the fuel collides with the wall portion 49 after being in the form of droplets, the droplets are integrated at the wall portion 49 and the atomization of the droplets is suppressed. Even if the fuel collides with the wall 49 when it is in the form of a liquid film, it is formed into droplets after the collision, so that it is difficult to prevent the droplets from being atomized.

[effect]
Next, the effect of the fuel injection valve 1 of Example 1 is listed below.
(1) A valve body 4 slidably provided, a valve seat 6 on which the valve body 4 sits when the valve is closed is formed on one end side, and is formed on the other end side of the valve seat member 7. A plurality of swirl imparting chambers 46 for imparting swirl to the fuel, and a nozzle plate 8 having a plurality of fuel injection holes 44 that communicate with each swirl imparting chamber 46 and inject fuel with the swirl imparted thereto, A convex wall portion 49 is formed between the fuel injection holes 44 on the other end side of the surface of the nozzle plate 8 where the swirl chamber 46 is formed.
Therefore, since fuel can be injected while avoiding the branch wall 50a of the intake port 50, it is possible to suppress the fuel from adhering to the branch wall 50a and improve fuel efficiency.
(2) The fuel and the wall 49 collide when the fuel injected from the fuel injection hole 44 is in the form of a liquid film.
Therefore, it is possible to make it difficult to prevent the droplets from being atomized.

[Example 2]
The fuel injection valve 1 according to the second embodiment will be described. The fuel injection valve 1 of the second embodiment is different from the fuel injection valve 1 of the first embodiment in the shape of the wall portion 49 of the nozzle plate 8. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
FIG. 10 is a single view of the nozzle plate 8, FIG. 10 (a) shows a front view, and FIG. 10 (b) shows a cross-sectional view. FIG. 11 is a perspective view of the nozzle plate 8. The configuration of the nozzle plate 8 will be described with reference to FIGS.
A protruding wall 49 is formed on the other side surface of the nozzle plate 8. The wall portion 49 is provided between the two fuel injection holes 44. On the side surface of the wall portion 49, a concave portion 49a cut into an arc shape is formed. The recess 49a is formed in an arc shape centered on the center O of the fuel injection hole 44 when the nozzle plate 8 is viewed from the axial direction. That is, the recess 49a is formed so as to be equidistant from the center of the fuel injection hole 44 when the nozzle plate 8 is viewed from the axial direction.

[Action]
In the fuel injection valve 1 of Example 2, the concave portion 49a is formed so as to be equidistant from the center of the fuel injection hole 44 when the nozzle plate 8 is viewed from the axial direction. The fuel injected from the fuel injection hole 44 spreads in a conical shape, and the kinetic energy of the fuel decreases as the distance from the fuel injection hole 44 increases. Since the distance from when the fuel is injected until it collides with the concave portion 49a of the wall 49 can be made constant, the kinetic energy of the colliding fuel becomes almost constant, and the spread of the fuel spray after the collision is stabilized. Can do.

[effect]
Next, effects of the fuel injection valve 1 of the second embodiment are listed below.
(3) On the side surface of the wall portion 49 on the fuel injection hole 44 side, an arcuate recess 49a having an equal distance from the center of the fuel injection hole 44 is formed.
Therefore, the kinetic energy of the fuel that collides with the wall portion 49 can be made substantially constant, and the spread of the fuel spray after the collision can be stabilized.

[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.
In the fuel injection valve 1 according to the first and second embodiments, the two swirl imparting chambers 46 are formed in the nozzle plate 8 and the fuel injection hole 44 is formed in each of them. In this configuration, for example, four swirl application chambers 46 may be formed in the nozzle plate 8 and the fuel injection holes 44 may be formed in each.
FIG. 12 is a perspective view of the nozzle plate 8. When four swirl application chambers 46 are formed in the nozzle plate 8, four fuel injection holes 44 are formed. In this case, a wall 49 may be provided between the two fuel injection holes 44 and the other two fuel injection holes 44 as shown in FIG.
Here, the case where the number of the fuel injection holes 44 is four is shown, but two or more may be sufficient, and the number may be an odd number, and is not particularly limited.
Further, in the fuel injection valve 1 of the first and second embodiments, one convex portion is used as the wall portion 49. In this configuration, for example, two convex portions may be formed and used as the wall portion 49.
FIG. 13 is a perspective view of the nozzle plate 8. For example, as shown in FIG. 13, two convex portions 49 b and 49 c may be formed and used as the wall portion 49. Although FIG. 13 shows a case where four fuel injection holes 44 are formed, the invention may be applied to a case where two fuel injection holes 44 are formed.
Further, in the fuel injection valve 44 of the first and second embodiments, the swirl chamber 41 and the fuel injection hole 44 are formed in the nozzle plate 8. For example, the swirl chamber 41 may be formed in the valve seat member 7. Alternatively, an intermediate plate may be provided between the valve seat member 7 and the nozzle plate 8, and the swirl chamber 41 may be formed in the intermediate plate.

1 Fuel injection valve
4 Disc
6 Valve seat
7 Valve seat member
8 Nozzle plate
44 Fuel injection hole
46 Swirl grant room
49 Wall

Claims (3)

A valve body slidably provided;
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 application chambers formed on the other end side of the valve seat member for applying a swirl to the fuel;
A nozzle plate having a plurality of fuel injection holes that communicate with each swirl application chamber and inject fuel with the swirl applied thereto;
Provided,
A fuel injection valve characterized in that a convex wall portion is formed between the fuel injection holes on the other end side of the surface of the nozzle plate on which the swirl application chamber is formed. The fuel injection valve according to claim 1, wherein
A fuel injection valve characterized in that the fuel and the wall collide when the fuel injected from the fuel injection hole is in the form of a liquid film. The fuel injection valve according to claim 1 or 2,
The fuel injection valve according to claim 1, wherein an arc-shaped recess having an equal distance from the center of the fuel injection hole is formed on a side surface of the wall portion on the fuel injection hole side.

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