JP2004293308A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a radiation noise at the time when a fuel injection valve is opened and closed, to secure the linearity of injection quantity by reduction of a bounce of a valve element, and to reduce abrasion. <P>SOLUTION: This fuel injection valve is pressed and fixed inside a metallic casing 1; presses and fixes a sleeve 21 composed of a nonmagnetic substance in and to a lower end part of a core member 4 magnetized by power supply of an electromagnetic coil 2; forms an orifice passage 22 by slightly increasing a diameter of an upper inner peripheral surface of an anchor 31 of the valve element 3 more than a diameter of an outer peripheral surface of the sleeve 21; communicates the orifice passage 22 with an orifice passage 23 formed between an anchor body outer peripheral surface and a casing inner peripheral surface between an upper end surface of the anchor 31 and a lower end surface of the core member 4; and forms a variable volume chamber 24 changing the volume by the movement of the valve element 3 (the anchor 31). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel injection valve for an internal combustion engine or the like, and more particularly to a technique for reducing a collision sound at the time of opening and closing a valve body to reduce radiated sound to the outside.
[0002]
[Prior art]
2. Description of the Related Art In general, in a fuel injection valve of an internal combustion engine or the like, a valve body which is urged by a return spring and is seated on a valve seat is lifted by an electromagnetic actuator or fuel pressure and opened.
[0003]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2002-534638
[Problems to be solved by the invention]
In such a fuel injection valve, a collision sound is generated when the valve body is opened and closed, specifically, a collision sound is generated when the valve is closed and a valve seat (or a connected body thereof) is collided with a stopper. The collision sound and the vibration caused by the collision propagate through the constituent members and are radiated from the hard resin molded to cover the casing, thereby forming a noise source.
[0005]
In addition, since the energy at the time of the collision of the valve body is large, there are problems that the bounce (bounce) is large, the linearity of the injection amount is impaired, and the wear of the collision surface increases.
[0006]
The present invention has been made in view of such a conventional problem, and it is possible to mitigate a collision at the time of opening and closing of a valve body, to effectively reduce radiated sound to the outside, and to reduce the bounce to reduce the linearity of the injection amount. It is an object of the present invention to provide a fuel injection valve which can ensure the fuel injection and reduce the wear of the collision surface.
[0007]
[Means for Solving the Problems]
Therefore, the present invention, in a fuel injection valve such as an internal combustion engine, a throttle passage in a space filled with fuel between a valve element driven in the axial direction and a fixed member provided on the upstream side of the valve element, A variable volume chamber which communicates through the throttle passage and changes in volume by movement of the valve body is formed.
[0008]
Thereby, when the fuel in the variable volume chamber enters and exits through the throttle passage when the valve element is driven to open and close, a fuel flow resistance is generated and the collision speed when the valve element is seated on the valve seat or the stopper by the damping function is reduced. As a result, collision noise and vibration are reduced, and radiation noise to the outside of the injection valve can be reduced.
[0009]
In addition, the bounce of the valve body due to the decrease in the collision energy can be reduced, so that the linearity of the injection amount can be secured, and the wear of the collision surface can be reduced.
Further, the tubular member is fixed inside the tubular core member magnetized by the electromagnetic coil, and the end of the tubular member is projected toward the valve body from the end of the core member. By forming the throttle passage between the surface and the inner peripheral surface of the cylindrical portion of the valve body, and by forming the variable volume chamber between end faces where the valve body and the core member abut, the minimum number of parts can be reduced. In addition, it can be easily configured at low cost.
[0010]
Further, a tubular member is fixed to an end of the valve body, and the end of the tubular member is projected from the end of the valve body toward the core member. By forming the restricting passage between the peripheral surface and the variable volume chamber between the end surfaces where the valve element and the core member abut, the configuration can be easily performed at a low cost by adding a minimum number of parts. can do.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example used for a fuel injection valve of an internal combustion engine (gasoline engine) according to the first embodiment.
[0012]
An electromagnetic coil 2 is fixed to the outside of a cylindrical casing 1 made of a magnetic material (metal), and a valve body in which a cylindrical anchor 31 and a ball 32 are welded and integrated inside the casing 1. 3 is slidably inserted in the axial direction. The lower peripheral wall of the anchor 31 is provided with a fuel passage hole 31a. The ball 32 has a plurality of flat surfaces 32a cut on the peripheral side.
[0013]
A cylindrical core member 4 is fixed to the inner wall of the casing 1 with a predetermined clearance above the valve body 3 (anchor 31) (it will be described based on the positional relationship in the illustrated state; the same applies hereinafter). A cylindrical spring stopper 5 is inserted and fixed in the core member 4, and a return spring 6 is inserted in a compressed state between a lower end of the spring stopper 5 and a stepped portion of the anchor 31, When the electromagnetic coil 2 is not energized, the valve body 3 is seated on the seating surface of the valve seat member 7 by the elastic compression force of the return spring 6 and is closed.
[0014]
A ball 32 of the valve body 3 is seated on the inside of the lower end of the casing 1 and a valve seat member 7 having an injection port opened at the center is welded to the lower end of the valve seat 3. The nozzle plate 8 having the opening is welded.
[0015]
A cap member 9 is fixed to the outside of the lower end of the casing 1, and the lower end of a coil cover 10 that covers the outside of the electromagnetic coil 2 is welded to the casing 1.
[0016]
A seal member 11 is fitted between an upper end flange portion of the cap member 9 and a step portion of the coil cover 10.
A fuel filter 12 is fitted and fixed to the upper end of the casing 1.
[0017]
A portion from the upper end of the coil cover 10 to the upper end of the casing 1 and a portion excluding the ends of the leads 2a of the electromagnetic coil 2 are molded by injection molding with a resin to form a resin casing 13. A seal member 14 is inserted between an upper end surface of the casing 13 and an upper end flange surface of the metal casing 1.
[0018]
The resin casing 13 forms a connector 13a around the end of the lead 2a of the electromagnetic coil 2.
In the fuel injection valve having such a basic configuration, in the present invention, a mechanism for alleviating a collision at the time of opening and closing the valve element is provided as follows.
[0019]
As shown in FIG. 2 in an enlarged manner, a sleeve (cylindrical member) 21 made of a non-magnetic material is fixed to the lower end of the core member 4 by press-fitting. 31 Increase the diameter of the upper inner peripheral surface slightly.
[0020]
Thus, an annular throttle passage 22 having a small passage cross-sectional area is formed between the outer peripheral surface of the sleeve 21 projecting below the core member 4 and the upper inner peripheral surface of the anchor 31. Also, by setting the gap between the outer peripheral surface of the sleeve 21 and the upper inner peripheral surface of the anchor 31 and the gap between the outer peripheral surface of the anchor 31 and the inner peripheral surface of the casing 1 to be substantially the same, the latter gap is also used as the throttle passage 23. Function.
[0021]
A variable volume chamber 24 is formed between the upper end surface of the anchor 31 and the lower end surface of the core member 4 and communicates with the throttle passages 22 and 23 and changes its volume by the movement of the valve element 3 (anchor 31). Is done.
[0022]
In the fuel injection valve configured as described above, fuel pumped by a fuel pump (not shown) is introduced into the casing 1 from the fuel filter 11 through a fuel pipe, and the fuel is supplied to the cylindrical spring stopper 5 and the anchor 31. It reaches the inside, flows out from the fuel through hole 31a to the outer space, and fills the gap between the flat surface 32a on the peripheral side of the ball 32 and the seating surface 7a to the portion where the ball 32 and the seating surface 7a are closed by contact. I have.
[0023]
When the electromagnetic coil 2 is energized, the core member 4 is magnetized, and the valve body 3 formed of a magnetic material is pulled upward by the electromagnetic attraction against the urging force of the return spring 6, and The stroke is performed to a position where the upper end surface comes into contact with the lower end surface of the core member 4.
[0024]
As a result, the ball 32 of the valve element 3 separates from the seating surface and opens the valve, and the fuel flows into the large-diameter injection port inlet 7b, passes through the small-diameter injection port 7c, flows out of the injection port outlet 7d, and the nozzle plate 8 Radially injected through a plurality of nozzle holes.
[0025]
Further, when the energization of the electromagnetic coil 2 is cut off, the valve body 3 is lowered by the urging force of the return spring 6 and abuts on the seating surface 7a to seat and close the valve.
When the valve element 3 is driven to open the valve, the fuel filled in the variable volume chamber 24 between the valve element 3 and the lower end surface of the core member 4 before the movement of the valve element 3 is changed to a variable volume by the elevation of the anchor 31. Due to the reduction in the volume of the chamber 24, it flows out from the lower end through the throttle passages 22 and 23. Since the rising speed of the valve body 3 is limited by the fuel flow resistance at this time, collision when the upper end surface of the anchor 31 abuts against the lower end surface of the core member 4 is mitigated, collision noise and vibration are reduced, and fuel injection is performed. Radiated sound to the outside of the valve can be reduced.
[0026]
On the other hand, when the valve element 3 is driven to close the valve, the volume of the variable volume chamber 23 increases from 0 due to the lowering of the anchor 31, and the fuel filled inside the sleeve 21 between the core member 4 and the anchor 31. Flows from the lower ends of the throttle passages 22 and 23 and flows out from the upper end so as to fill the variable volume chamber 23. Since the lowering speed of the valve body 3 is limited by the fuel flow resistance at this time, the collision when the valve body 3 (ball 32) hits the seating surface 7a of the valve seat member 7 is reduced, and the collision noise and vibration are reduced. Therefore, the radiation noise to the outside of the fuel injection valve can be reduced. Further, since the throttle passages can be formed on both the inner and outer peripheral sides of the anchor, the fluid resistance can be increased as compared with the case where the throttle passage is provided on one of the anchor passages. There is.
[0027]
Further, the bounce of the valve body 3 due to the decrease in the collision energy can be reduced, so that the linearity of the injection amount can be secured and the wear of the collision surface can be reduced.
FIG. 3 shows a main part of a second embodiment of the present invention.
[0028]
In this embodiment, a sleeve (cylindrical member) 21 ′ made of a non-magnetic material is fixed to the inner peripheral surface of the upper end portion of the anchor 31 by press-fitting, and the inner diameter of the lower portion of the core member 4 is determined based on the diameter of the outer peripheral surface of the sleeve 21 ′. Increase the diameter of the peripheral surface a little.
[0029]
Thus, an annular throttle passage 22 ′ having a small passage cross-sectional area is formed between the outer peripheral surface of the sleeve 21 ′ projecting above the anchor 31 and the lower inner peripheral surface of the core member 4, Between the end face and the lower end face of the core member 4, there is formed a variable volume chamber 24 whose volume is changed by the movement of the valve body 3 (anchor 31). By setting the gap between the outer peripheral surface of the sleeve 21 'and the inner peripheral surface of the lower part of the core member 4 and the clearance between the outer peripheral surface of the anchor 31 and the inner peripheral surface of the casing 1 to be substantially the same, the latter clearance can be reduced. The function as 23 is the same as in the first embodiment.
[0030]
When the valve element 3 is driven to open the valve, the fuel filled in the variable volume chamber 24 is reduced via the throttle passages 22 ′ and 23 by the reduction of the volume of the variable volume chamber 24 due to the rise of the anchor 31. Outflow.
[0031]
On the other hand, when the valve element 3 is driven to close the valve, the volume of the variable volume chamber 23 increases due to the lowering of the anchor 31, and the fuel filled inside the sleeve 21 between the core member 4 and the anchor 31 is The air flows into the variable volume chamber 24 through the throttle passages 22 ′ and 23 so as to fill the variable volume chamber 24.
[0032]
As described above, also in the present embodiment, the movement speed of the valve body 3 is limited by the resistance when the fuel flows through the throttle passages 22 'and 23 when the valve body 3 is opened and closed, so that the collision at the time of sitting is alleviated, and the collision noise is reduced. Thus, vibration is reduced, and radiation noise to the outside of the fuel injection valve can be reduced. In addition, the bounce of the valve body due to the decrease in the collision energy can be reduced, so that the linearity of the injection amount can be secured, and the wear of the collision surface can be reduced.
[0033]
Further, technical ideas other than the claims that can be grasped from the embodiment will be described below together with their effects.
(A) In the fuel injection valve according to claim 2 or 3, the throttle passage includes a gap between an outer peripheral surface of a cylindrical portion of the valve body and an outer casing slidable on the outer peripheral surface of the cylindrical portion. It is characterized by comprising.
[0034]
Thereby, the gap between the outer peripheral surface of the cylindrical portion of the valve body and the outer casing also functions as a throttle passage.
(B) The fuel injection valve according to claim 2, 3, or (a), wherein the cylindrical member is formed of a non-magnetic material.
[0035]
With this configuration, it is possible to prevent the leakage of the magnetic flux between the core member and the valve body, and does not affect the opening / closing driving force.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a configuration of a fuel injection valve of an internal combustion engine according to a first embodiment of the present invention.
FIG. 2 is an enlarged view of a main part of the fuel injection valve.
FIG. 3 is an enlarged sectional view of a main part of a fuel injection valve of an internal combustion engine according to a second embodiment of the present invention.
[Explanation of symbols]
2 ... Electromagnetic coil 3 ... Valve 4 ... Core member 6 ... Return spring 7 ... Valve seat member 7a ... Seat surface 21,21 '... Sleeve 22,22' ... Throttle passage 23 ... Throttle passage 24 ... Variable volume chamber

Claims (3)

A space is filled with fuel between the valve body driven in the axial direction and a fixed member provided on the upstream side of the valve body. And a variable volume chamber that forms the fuel injection valve. The fixing member is a cylindrical core member magnetized by an electromagnetic coil, and the cylindrical member is fixed inside the core member so that the end of the cylindrical member is closer to the valve body than the end of the core member. Protruding to form the throttle passage between the outer peripheral surface of the tubular member and the inner peripheral surface of the tubular portion of the valve body, and to form the variable volume chamber between the end faces where the valve body and the core member abut. The fuel injection valve according to claim 1, wherein: The fixing member is a cylindrical core member magnetized by an electromagnetic coil, and the cylindrical member is fixed to an end of a valve body, and the end of the cylindrical member is closer to the core member than the end of the valve body. To form the throttle passage between the outer peripheral surface of the cylindrical member and the inner peripheral surface of the core member, and form the variable volume chamber between end faces where the valve element and the core member abut. The fuel injection valve according to claim 1, wherein:

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