JP2518032Y2 - Fuel injection valve - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection valve used in an electronically controlled fuel injection system for an internal combustion engine and injecting fuel into an intake system of the engine.

[0002]

2. Description of the Related Art As a conventional fuel injection valve, for example, there is one shown in FIG. 3 (see Japanese Patent Application Laid-Open No. 1-249960). To explain this, this fuel injection valve 10
The inner wall of the housing 11 has a solid core 12 made of, for example, iron.
However, one end of the core 12 is opposed to the one end face 32 side of the valve body 31 described later, and the other end is abutted against the inner wall of the housing 11 to be fixed.

The core 12 is made of resin and has an electromagnetic coil.
The coil bobbin 14 mounted by winding 13 is locked. Further, the pair of terminal holding portions 15 are inserted into the terminal extraction holes 16 so that the pair of terminals 17 is projected outward from the housing 11, and the space between the pair of terminals 17 and the core 12 is separated from the housing 11 for fuel. An O-ring 18 is attached to prevent leakage of the oil.

A valve seat 21 having a circular seal surface portion 20 projecting toward the core 12 is provided at the tip of the housing 11 via a holder 19, and an injection hole 22 is provided at the center of the valve seat 21. A flat injection hole plate 23 is provided. When the electromagnetic coil 13 is not energized, the core 12 is attached to the sealing surface portion 20 of the valve seat 21.
A disk-shaped valve body 31 made of a magnetic material and having a plurality of fuel passage holes 33 on a concentric circle larger than the outer diameter of the valve seat 21 and the sealing surface portion 20 provided on the valve seat 21 is closed and held.

Between the valve seat 21 and the intermediate housing 24, the inner peripheral surface 42 is disposed so as to be close to the outer peripheral surface 34 of the valve body 31.
The gap adjusting member 41 is formed in an annular shape with a thickness t slightly larger than the outer peripheral surface 34 of the valve body 31, and the outer peripheral edge portion is a holder.
An annular leaf spring 51 that is supported by 19 and presses the peripheral edge portion 35 of the valve body 31 on the inner side of the valve seat facing surface 52 to urge the valve body 31 against the seal surface portion 20 of the valve seat 21 under pressure. A magnetic disk 61 for forming a magnetic path having a stopper 62 as a seating surface on which one end surface 32, which is the side opposite to the valve seat of the valve body 31, is seated, in this order, so as to come close to the valve seat 21. ing. An electromagnet is formed by the core 12, the electromagnetic coil 13, and the magnetic disk 61, and the housing, the magnetic disk 61, the valve body 31, and the core 12 form a magnetic path.

Here, the fuel is introduced into the housing 11 through the fuel inlet 25 opened in the housing 11 and
26, and the valve body 31 is attracted upward in the figure until it comes into contact with the stopper 62 of the magnetic disk 61 by the electromagnetic attraction force generated in the core 12 by the electromagnetic coil 13, and is separated from the valve seat 21 to remove the high pressure chamber 26. The fuel inside is ejected from the injection hole 22. 27
Is a fuel outlet, and returns excess fuel to the tank through a fuel pressure regulator (not shown) to maintain the fuel pressure of the high pressure chamber 26 constant. The fuel injection valve 10 of this type is arranged in the intake passage upstream of the throttle valve.

[0007]

In such a conventional fuel injection valve 10, when the valve body 31 is opened by the electromagnetic coil 13, the one end face 32 of the valve body 31 is always the magnetic disk 61. Although it comes into contact with the stopper 62, the stopper 62 of the magnetic disk 61 is always at the one end face 32 due to the leaf spring 51 pressing the peripheral portion 35 of the valve body 31.
It will come into contact with the same place above. Here, the valve body 31 is provided with a plurality of fuel passage holes 33 concentrically, but when the position of the fuel passage hole 33 and the position of the stopper 62 do not overlap, the contact is repeated. The contact surface is acclimated and comes into intimate contact with each other. The surface tension gradually increases, and the adhesive force related to the surface tension also increases. As a result, the responsiveness may fluctuate and the dynamic flow rate of fuel from opening to closing, that is, the flow rate per stroke of the valve body 31, may change over time, which causes a problem of unstable fuel injection characteristics. .

The present invention has been made in view of such a conventional situation, and by defining the positional relationship between the fuel passage hole on the valve body and the stopper of the magnetic disk,
An object of the present invention is to provide a fuel injection valve that stabilizes the adhesive force related to the surface tension and thus stabilizes the dynamic flow rate characteristic of fuel.

[0009]

Therefore, in the present invention, a disk-shaped valve body having a plurality of fuel passage holes arranged concentrically, and the valve body on the inner peripheral side of the fuel passage holes are provided. Position, a leaf spring that biases the valve seat in the direction to be seated, and lifts the valve element against the biasing force of the leaf spring until the opposite valve seat side surface of the valve element seats on a predetermined seating surface. In the fuel injection valve including an electromagnet for opening the valve, the fuel passage hole of the valve body and the predetermined seating surface are provided so as to overlap each other.

[0010]

With this configuration, when the valve body is lifted by the electromagnet against the biasing force of the leaf spring and is seated on the predetermined seating surface to open the valve, a plurality of valves provided on the valve body are provided. The fuel passage hole and the predetermined seating surface are seated on top of each other. As a result, the contact area between the predetermined seating surface and the non-valve side surface of the valve body is reduced, the surface tension is also reduced, the adhesive force related to the surface tension is stabilized, and the responsiveness is also stabilized. Therefore, the dynamic flow rate of fuel from opening to closing of the valve, that is, the flow rate per stroke of the valve body is stabilized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. Incidentally, the same elements as those of the conventional example shown in FIG. The valve body 1 made of a magnetic material has nine fuel passage holes 2 which are larger than the outer diameter of the core 12 and the concentric circle 3 which is larger than the seal face portion 20 provided on the valve seat 21.
The fuel passage hole 2 is formed so as to overlap the stopper 62 of the magnetic disc 61.

With this structure, the core 12, the electromagnetic coil 13, and the magnetic disk 61 form a leaf spring.
When the valve body 1 is lifted against the urging force of the valve 51 and is seated on the stopper 62 of the magnetic disc 61 to open the valve, the nine fuel passage holes 2 provided in the valve body 1 are It will be seated on the stopper 62 of the disk 61. Therefore, the contact area between the stopper 62 of the magnetic disc 61, which is a predetermined seating surface, and the non-valve seat side surface 4 of the valve body 1 is reduced. Accordingly, the surface tension when the valve seat side 4 of the valve body 1 is separated from the stopper 62 by the pressing force of the leaf spring 51 from the valve opening to the valve closing, that is, the electromagnetic coil 13 is de-energized, is small, The adhesive strength does not increase, and the responsiveness does not change. Therefore, the dynamic flow rate of fuel from opening to closing, that is, the flow rate per stroke of the valve body 1 does not change, and the fuel injection characteristic is stabilized.

Further, when the valve is opened, the fuel stored in the high pressure chamber 26 flows into the injection hole 22 through the gap c formed by the magnetic disk 61 and the fuel passage hole 2.
Since the flow velocity of the fuel passing through the gap c is high, the force of the fuel to permeate between the stopper 62 and the valve body 1 which is generated depending on the flow velocity also becomes large, and the permeation force also causes the valve opening to the valve closing. The transition time to becomes shorter, and the dynamic flow rate of fuel stabilizes.

In the fuel injection valve according to this embodiment, the valve body 1
Although the nine fuel passage holes 2 are formed in the above description, it is needless to say that the plurality of fuel passage holes 2 may be formed so as to overlap the stopper 62.

[0015]

As described above, according to the present invention,
Since the predetermined seating surface on which the valve body of the fuel injection valve is seated when the valve is opened is provided at a position that overlaps the fuel passage hole of the valve body, the predetermined seating surface when the valve is opened and the anti-valve of the valve body The contact area with the seat side surface is reduced, the surface tension is also reduced, the adhesive force related to the surface tension is stabilized, and the responsiveness is also stabilized. Therefore, the dynamic flow rate of the fuel can be stabilized, and the quality can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a perspective view taken along line AA in FIG.

FIG. 3 is a sectional view showing an example of a conventional fuel injection valve.

[Explanation of symbols]

 1 valve body 2 fuel passage hole 4 side surface opposite valve seat 12 core 21 valve seat 61 magnetic disk 62 stopper

Claims (1)

(57) [Scope of utility model registration request] 1. A disk-shaped valve body having a plurality of fuel passage holes arranged concentrically, and pressing the valve body at a position on the inner peripheral side of the fuel passage holes on a valve seat. A biasing leaf spring; and an electromagnet that lifts the valve body against the biasing force of the leaf spring until the valve seat side surface of the valve body seats on a predetermined seating surface to open the valve. In the configured fuel injection valve, the fuel injection valve is provided such that the fuel passage hole of the valve body and the predetermined seating surface overlap each other.