JP2002339831A - Fuel injector of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injector of an internal combustion engine capable of surely closing a valve by valve elements even if a thermal expansion difference between a fuel injection valve body and the valve elements has occurred, and also capable of enhancing valve closing responsiveness by a valve closing solenoid. SOLUTION: This fuel injector is provided with the valve elements 6 and 7 for opening and closing a nozzle port 1a, a valve closing core 5, the valve closing solenoid 11 for generating magnetic attraction force between the valve closing core and the valve elements. The valve closing core is made movable, and moves together with the valve elements when the valve elements do not close the nozzle port even if the valve elements abut on the valve closing core by the magnetic attraction force, and enables the valve elements to close the nozzle port.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel injection device for an internal combustion engine.

[0002]

2. Description of the Related Art An electromagnetic type fuel injection device for an internal combustion engine is generally used. The electromagnetic fuel injection device has a valve element for opening and closing the injection hole, a spring for urging the valve element in a valve closing direction, and a solenoid. When the fuel injection is started, the solenoid is energized to open the valve body against the spring force by the magnetic attraction force generated between the valve body and the core, and when the fuel injection is completed, the solenoid is stopped. Then, the valve body is closed by the spring force.

[0003] In this fuel injection device, the valve opening response of the valve element can be improved by weakening the spring force. However, with the weakened spring force, the valve closing response of the valve body deteriorates. Japanese Patent Application Laid-Open No. 7-239050 discloses that in an electromagnetic fuel injection device, in addition to the above-described solenoid (hereinafter, a valve-opening solenoid), a solenoid (hereinafter, a solenoid that generates a magnetic attraction force for closing a valve element). It has been proposed to provide a solenoid for closing the valve. Thus, when the valve is closed, the magnetic attraction force generated between the valve body and the valve closing core by the valve closing solenoid acts on the valve body in addition to the weakened spring force. It can be improved.

[0004] In such a fuel injection device having a valve closing solenoid, in order to ensure that the valve is closed by the valve, the valve is attached to the seat before the valve comes into contact with the valve closing core. The valve closing must be completed by abutting, that is, a gap must be provided between the valve closing core and the valve body even when the valve is closed.

[0005]

By the way, generally,
During use, the fuel injection device receives heat from the engine body and thermally expands. However, since the valve body in the fuel injection device main body is constantly exposed to the fuel supplied from the fuel tank, the valve body does not thermally expand much, and a difference in thermal expansion occurs between the valve body and the fuel injection device main body. In the prior art described above, in order to ensure that the valve body closes the valve even when this difference in thermal expansion occurs, the gap between the valve closing core and the valve body at the time of closing the valve is relatively large. Must be set.

As a result, the distance between the valve-closing core and the valve body when the valve is opened becomes very large, and even if the valve-closing solenoid is energized when the valve is closed, the valve-closing core and the valve body are not connected to each other. The magnetic attraction generated between them is so small that the valve closing response cannot be enhanced as intended.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to ensure that the valve is closed by the valve even if a thermal expansion difference occurs between the fuel injection valve body and the valve, and to provide a valve closing solenoid. It is an object of the present invention to provide a fuel injection device for an internal combustion engine, which can enhance valve closing responsiveness.

[0008]

According to a first aspect of the present invention, there is provided a fuel injection device for an internal combustion engine, which opens and closes an injection hole, a valve closing core, the valve closing core and the valve closing core. A valve closing solenoid for generating a magnetic attraction force between the valve body and the valve body; the valve closing core is movable; and the valve body is moved by the magnetic attraction force to the valve closing core. The valve body moves together with the valve body when the valve body does not close the injection hole even when the nozzle hole contacts the nozzle hole, thereby enabling the valve body to close the injection hole.

According to a second aspect of the present invention, there is provided a fuel injection device for an internal combustion engine according to the first aspect, wherein the biasing means biases the valve body in a valve closing direction. A valve opening core; and a valve opening solenoid for generating magnetic attraction between the valve opening core and the valve element.

According to a third aspect of the present invention, there is provided a fuel injection device for an internal combustion engine according to the first or second aspect, wherein the valve body and the valve closing core are opposed to each other. A protrusion is provided on at least one of the opposed surfaces to reduce the contact area when the valve body contacts the valve closing core.

[0011]

FIG. 1 is a sectional view showing a fuel injection device for an internal combustion engine according to the present invention. The present fuel injection device injects, for example, high-pressure fuel pressurized in the accumulator 30 in order to directly inject fuel into the cylinder of the internal combustion engine. Of course, the present fuel injection device can also be used to inject fuel to, for example, an intake port other than in the cylinder. 1
Is a front end portion of the main body having the injection hole 1a, and a tube member 2 constituting a central portion of the main body is attached to the opposite side of the injection hole 1a. A main body base end 3 is attached to the tube member 2 on the side opposite to the main body front end 1.

In this manner, the internal space of the main body distal end portion 1, the internal space of the tube member 2, and the internal space of the main body proximal end portion communicate with each other. In particular, the pipe member 2 is formed of a magnetic material such as iron, and a valve-opening core 4 and a valve-closing core 5 also formed of a magnetic material are arranged in the internal space so as to be spaced apart in the axial direction. Have been. The valve closing core 5 is located closer to the injection hole 1a than the valve opening core 4. Valve opening core 4
Is fixed to the pipe member 2, whereas the valve closing core 5
Is not fixed and is movable in the axial direction in the pipe member 2. However, the collar member 15 is arranged between the valve-opening core 4 and the valve-closing core 5, and the movement of the valve-closing core 5 in the direction of the valve-opening core 4 is restricted by the collar member 15. The distance between the valve-opening core 4 and the valve-opening core 5 does not become smaller than the set dimension. The end face of the valve-closing core 5 on the side opposite to the collar member 15 is pressed by a spring 16 disposed on a support plate 2c fixed in the pipe member 2, so that in normal times, The valve-closing core 5 abuts against the collar member 15, and the collar member 1 is provided between the valve-opening core 4 and the valve-closing core 5.
The set size is equivalent to the length of 5. A cylindrical movable member 6 having a width smaller than the set dimension is slidably disposed in the collar member 15 between the two cores 4 and 5. The valve closing core 5 is a valve opening core 4.
It has a smaller wall thickness.

The movable member 6 is provided with a valve member 7 extending through the internal space of the valve closing core 5 to form a valve body.
The injection hole 1a of the main body front end 1 can be closed by the front end of the valve member 7. A cylindrical pressing member 8 is arranged in the internal space of the valve opening core 4, and the valve body is urged in a valve closing direction by a spring 9 supported by the pressing member 8. The valve member 7 is hollow at a portion located inside the valve closing core 5, and a hole is formed at a portion located outside the valve closing core 5 to communicate the hollowed internal space with the outside. . In this way, the plurality of members described above are arranged in the pipe member 2,
The internal space of the main body distal end portion 1, the internal space of the pipe member 2, and the internal space of the main body proximal end portion are sufficiently maintained to communicate with each other and constitute a fuel passage.

Outside the pipe member 2, a valve-opening solenoid 10 is disposed around the valve-opening core 4, and a valve-closing solenoid 11 is disposed around the valve-closing core 5. The number of coil turns of the valve closing solenoid is smaller than that of the valve opening solenoid. Valve opening solenoid 10
A first case 12 surrounding the valve closing solenoid 11 in a radial direction and an axial direction is attached to the pipe member 2 as a part of the main body. The first case 12 and the second case 13 are:
The first case 12 is formed to be relatively thicker than the second case 13. The first case 12 and the second case 13 are separated from each other in the axial direction, and thus, a concave portion 14 extending in the circumferential direction is formed outside the main body of the fuel injection device.

The movable member 6 disposed in the pipe member 2 is also formed of a magnetic material. Outside the movable member 6, at substantially the same position as the concave portion 14 outside the main body, the movable member 6 is wider than the concave portion 14 and extends in the circumferential direction. An extended recess 6a is formed. Thus, the movable member 6 has the donut-shaped first portion 6b located on the valve-opening solenoid 10 side defined by the recess 6a.
And a donut-shaped second portion 6c located closer to the valve-closing solenoid 11 than the concave portion 6a.

In the fuel injection device thus constructed, the valve-opening core 4 made of a magnetic material, the first case 12, and the first portion 6 b of the movable member 6 are located around the valve-opening solenoid 10. Constitutes a first magnetic circuit in which a magnetic flux is generated by energizing the valve opening solenoid 10. The valve-closing core 5, the second case 13, and the second portion 6c of the movable member 6, which are located around the valve-closing solenoid 11 and are made of a magnetic material, are energized by the valve-closing solenoid 11. A second magnetic circuit that generates a magnetic flux is configured. In order to reliably form such a first magnetic circuit and a second magnetic circuit, a magnetic circuit is not formed only by the tube member 2 itself formed of a magnetic material and the first case 12 or the second case 13. And the non-magnetic portions 2a, 2
b is provided. The nonmagnetic portions 2a and 2b may be formed by demagnetizing a part of the tube member 2, or may be formed by replacing a part of the tube member 2 with a nonmagnetic material.

When the solenoid 10 for opening a valve and the solenoid 11 for closing a valve are both in a non-energized state, the valve body constituted by the movable member 6 and the valve member 7
To close the injection hole 1a. When the injection hole 1a is closed in this manner, the pressure receiving area in the valve opening direction of the valve element is smaller than the pressure receiving area in the valve closing direction by the opening area of the injection hole 1a. 7 is further urged in the valve closing direction.
As a result, the injection hole 1a is reliably closed by the valve body, and fuel leakage through the injection hole 1a is prevented.

When fuel injection is started, energization of the valve opening solenoid 10 is started. As a result, a magnetic flux is generated in the first magnetic circuit, and the first magnetic circuit is connected to the first portion 6b of the movable member 6 constituting a part of the first magnetic circuit in order to minimize the magnetic resistance. A magnetic attraction force is generated between the core 4. Thus, the movable member 6 is sucked by the valve-opening core 4, and at the same time, the high-pressure fuel in the fuel passage is injected through the injection hole 1a because the valve member 7 releases the injection hole 1a. If a spring having a low elastic modulus is used as the spring 9 for urging the valve body 7 in the valve closing direction, the valve opening responsiveness of the valve opening solenoid 10 can be improved.

The magnetic attraction force in the valve opening direction must be relatively large because the valve element must be opened against the urging force of the spring 9 and the fuel pressure acting on the pressure receiving area difference described above. No. As a result, the valve opening solenoid 10 requires a large number of coil turns in order to secure the inductance therefor, and the length of the valve opening solenoid 10 is relatively long. Thus,
The length of the first magnetic circuit surrounding the valve opening solenoid 10 is inevitably relatively long. Even if the inductance of the valve-opening solenoid 10 is increased, if the magnetic resistance of the first magnetic circuit is large, a relatively large magnetic attraction cannot be generated, and the magnetic resistance of the relatively long first magnetic circuit is reduced. To do so, the cross-sectional area must be increased.

Therefore, as described above, the thicknesses of the valve-opening core 4, the first case 12, and the movable member 6 constituting the first magnetic circuit are set to increase the sectional area of the first magnetic circuit. It is relatively thick. Further, the width of the first portion 6b of the movable member 6 is relatively thick in order to increase the sectional area of the first magnetic circuit.

On the other hand, when terminating the fuel injection, the power supply to the valve opening solenoid 10 for opening the valve is stopped and the power supply to the valve closing solenoid 11 for closing the valve is started. At this time, although the magnetic flux remains in the first magnetic circuit, as described above, the magnetic flux is immediately applied to the second magnetic circuit because the second magnetic circuit is formed independently of the first magnetic circuit. Occurs
The second magnetic circuit generates a magnetic attraction force between the second portion 6c of the movable member 6 and a core 5 for closing the valve, which constitute a part of the second magnetic circuit, in order to minimize the magnetic resistance. Thus, the movable member 6 is sucked into the valve-closing core 4 with good response, and at the same time, the valve body closes the injection hole 1a, so that the fuel injection is terminated.

Since the biasing force of the spring 9 is applied to the valve closing of the valve body 7, the magnetic attraction in the valve closing direction can be made smaller than the magnetic attraction in the valve opening direction described above. Thus, the valve closing solenoid 11 can reduce the inductance as compared with the valve opening solenoid 10, and can reduce the number of coil turns.
Thus, the length of the valve-closing solenoid 11 is shorter than that of the valve-opening solenoid 10, and the length of the second magnetic circuit surrounding the valve-closing solenoid 11 can be reduced. In order to efficiently generate a magnetic attraction force by the valve closing solenoid 11, it is preferable that the magnetic resistance of the second magnetic circuit is reduced. Even if the magnetic resistance of the second magnetic circuit is made equal to that of the first magnetic circuit, the cross-sectional area can be smaller than that of the first magnetic circuit because the length of the second magnetic circuit is short.

Accordingly, as described above, the thicknesses of the valve closing core 5 and the second case 13 constituting the second magnetic circuit are made relatively thin. Also, the second part 6 of the movable member 6
The width of c can be made thinner than that of the first portion 6b. Accordingly, the overall weight of the movable member 6 can be reduced, so that the valve closing response and the valve opening response of the valve body including the movable member 6 can be further increased.

As shown in FIG. 1, the present fuel injection device has an engine main body 40 having a main body front end 1 having substantially the same shape as the main body front end 1.
The end face 1 of the main body tip 1 is inserted into a mounting hole formed in the
b is attached to the engine body 40 by being pressed through the ring member 20. Attachment on the side of the pressure accumulating chamber 30 is as simple as inserting the base end portion 3 around which the elastic seal 32 is disposed into the fuel pipe 31 of the pressure accumulating chamber 30. The main body front end portion 1 has two steps, and the mounting hole of the engine body 40 also has two similar steps, and the ring-shaped elastic seal 22 is pressed by the opposing steps, whereby fuel injection is performed. The gas pressure on the injection hole 1a side of the device can be kept airtight, and the injection hole 1a of the present fuel injection device can be located in the cylinder.

Incidentally, in the present fuel injection device, since the first magnetic circuit and the second magnetic circuit are formed independently, the concave portion 14 is provided on the outside of the main body as described above. At the position of the concave portion 14, since only the relatively thin tube member 2 exists as the main body, the strength of the main body is greatly reduced at this position.

However, as described above, the present fuel injection device is mounted so that the mounting axial force acts only on the front end portion 1 of the main body. That is, since the compressive stress at the time of mounting is generated only at the distal end portion 1 of the main body and is not generated at the position of the concave portion 14 of the main body having low strength, buckling deformation of the main body can be prevented. Of course, the mounting axial force may be applied to any other position on the main body if the mounting axial force is not applied to the concave portion of the main body.

In a general fuel injection device, the movable member 6 can be brought into contact with the valve-opening core 4 when the valve is opened. However, when the valve is closed, the movable member 6 is brought into contact with the valve-close core. 5 cannot be abutted. Because
This is because it is difficult for the valve member 7 to close the injection hole simultaneously with this contact. Thus, in a general fuel injection device, the design dimensions of each part are determined so that a gap is provided between the movable member 6 and the valve closing core 5 when the valve is closed.

Further, the fuel injection device receives heat from the engine main body during use, and particularly, the main body front end portion 1, the pipe member 2, and the main body base end portion 3, that is, the fuel injection device main body has a relatively large thermal expansion in the axial direction. I do. On the other hand, since the valve element is located in the fuel passage filled with the fuel supplied from the fuel tank, heat conduction from the engine body is small, and the valve element does not thermally expand much. In this manner, since a difference in thermal expansion between the fuel injection device main body and the valve body is generated, in a general fuel injection device, the movable member 6 and the valve closing valve are required to ensure that the injection hole 1a is closed by the valve body. The gap between the core 5 must be set relatively large. However, when the gap is increased, the movable member 6 and the valve-closing core 5 are largely separated from each other when the valve is opened. Thereby, when closing the valve, the valve closing coil 11 is closed.
Unless the size of the valve member is increased, a large magnetic attraction force cannot be generated between the movable member 6 and the valve-closing core 5, and a general fuel injection device has a desired valve-closing responsiveness as intended. Can't increase.

On the other hand, in the present fuel injection device, since the valve closing core 5 is movable as described above, the gap between the movable member 6 and the valve closing core 5 when the valve is closed is set. Need not be designed so large. Because if
Even if a thermal expansion difference occurs between the fuel injection valve main body and the valve body, and the movable member 6 abuts on the valve closing core 5, the valve member 7 does not close the injection hole 1a even if the injection hole 1a is not closed. As shown in FIG. 7, the urging force of the spring 9 causes the valve closing core 5 to move in the axial direction together with the movable member 6, so that the injection hole 1a can be closed by the valve member 7.

Needless to say, for this purpose, the urging force acting on the valve body by the spring 9 in the valve closing direction must be set larger than the pressing force acting on the valve closing core 5 by the spring 16. In this way, the gap between the movable member 6 and the valve-closing core 5 can be set small when the valve is closed, and the movable member 6 does not largely separate from the valve-close core 5 when the valve is opened. Valve coil 1
A large magnetic attraction force can be generated without increasing the size of the valve 1 and the valve-closing responsiveness can be reliably increased.

As described above, in the present fuel injection device, upon closing the valve, after the movable member 6 comes into contact with the valve closing core 5 by magnetic attraction, the valve is finally closed by the urging force of the spring 9. Will be valved. Of course, also in this case, the valve closing responsiveness can be improved because a magnetic attraction force is applied at the beginning of closing the valve body, rather than closing the valve body only by the spring 9. However, if the valve closing period by the spring 9 becomes longer,
The valve-closing response cannot be sufficiently increased.

In the present fuel injection device, the design dimension between the movable member 6 and the valve-closing core 5 at the time of closing the valve is reduced as compared with a general fuel injection device. If it is too long, the movable member 6 comes into contact with the valve closing core 5 well before the closing of the injection hole 1a by the valve body, which is not preferable because the valve closing period by the spring 9 becomes long. Thus, it is necessary to appropriately design the gap between the movable member 6 and the valve-closing core 5 when the valve is closed. For example, a large thermal expansion occurs between the fuel injection device main body and the valve body during use. It is desirable that the movable member 6 be brought into contact with the valve closing core 5 immediately before the valve element closes the injection hole only when a difference occurs. Thereby, the magnetic attraction generated mainly by the valve-closing solenoid can be applied to the valve element during closing of the valve element, and the valve-closing responsiveness of the valve element can be sufficiently improved.

In a general fuel injection device, the first portion 6b of the movable member 6 is assumed to abut on the valve opening core 4.
In practice, there is a very thin fuel fluid film between the first portion 6b and the valve opening core 4. This is because a very large pressing force is required due to the squeeze film effect in order to completely push out the liquid between the two members.
This is because such a large pressing force cannot be generated between b and the valve opening core 4. However,
When the valve is opened, even if the first portion 6b of the movable member 6 does not completely contact the valve opening core 4 by the fluid film, the injection hole 1a
Since the valve is opened, there is no particular problem in opening the valve. Further, the speed of the movable member 6 at the end of the valve opening operation can be reduced by the squeeze film effect, and the movable member 6 is prevented from colliding with the valve opening core 4 at high speed and rebounding.

However, when a squeeze film effect is generated on the relatively large opposing surface between the movable member 6 and the valve opening core 4 when the valve is opened, the movable member 6 and the valve are opened by the squeeze film effect when the valve is closed. A relatively large suction force is generated between the valve core 4 and the valve core 4 and deteriorates the valve closing response. Thus, in the present fuel injection device, a ring-shaped projection 6d is provided on the surface of the movable member 6 facing the valve opening core 4, and when the valve is closed, the squeeze film effect is generated with a small area of the projection 6d. It has become. Thereby, rebound of the movable member 6 can be prevented by the squeeze film effect when the valve is opened, and a large suction force is generated between the movable member 6 and the valve opening core 4 when the valve is closed. Never.

The opposite surfaces of the projection 6d and the valve-opening core 4 are plated with a non-magnetic material.
The magnetic attraction of the valve and the valve-opening core 4 due to the permanent magnet is weakened, thereby preventing the valve-closing responsiveness from being deteriorated by the magnetic attraction. The protrusion 6d may of course be provided on the valve opening core 4 side instead of the movable member 6.

In a general fuel injection device, as described above, a gap is provided between the movable member and the valve-closing core when the valve is closed in order to ensure that the valve is closed. Therefore, when the valve is closed, the squeeze film effect cannot be generated on the valve body. As a result, the valve member 7 may collide with the injection hole 1a at a high speed and rebound from the injection hole 1a due to the magnetic attraction force when the valve is closed, and fuel may be unnecessarily injected from the opened injection hole 1a again. However, as described above, the present fuel injection device does not
Immediately before closing the injection hole 1a, the movable member 6
, The speed at the end of the valve closing operation of the valve body can be reduced by the squeeze film effect,
The fuel injection can be reliably stopped by preventing rebound.

In the present fuel injection device, a projection 6e equivalent to the projection 6d is also provided on the surface of the movable member 6 facing the valve closing core 5. As described above, the squeeze film effect is generated in the small area of the projection 6e to prevent rebound, and the squeeze film is interposed between the movable member 6 and the valve-closing core 5 when the valve is opened. There is no large suction force associated with the effect. Protrusion 6
e and the opposite surface of the valve closing core 5 are plated with a non-magnetic material as described above, and the protrusion 6e can be provided on the valve closing core 5 side.

In the present fuel injection device, the movable member 6 and the valve body 7 are formed as separate members and are joined to each other to form a valve body. Alternatively, only the distal end of the valve member 7 may be a separate member. The movable member 6 is configured such that the first portion 1b and the second portion 1c are magnetically interrupted by the concave portion 1a, that is, by the fuel present in the concave portion 1a located in the fuel passage. The non-magnetic material may be inserted into the concave portion 1a, and the first and second portions of the magnetic material joined to both sides of such a ring-shaped non-magnetic material may be used as a movable member. It is also possible to use as.

In the present fuel injection device, only the valve-closing core 5 is movable. However, this is not a limitation of the present invention. 5, the same effect can be obtained even when these are entirely movable. In this case,
A stop member for restricting the movement of the entire valve body in the valve opening direction is required, but whether or not the movable member 6 contacts the valve closing core 5 to move the valve closing core 5 when closing the valve. Regardless, the distance between the movable member 6 and the valve-opening core 4 when the valve is closed can be kept relatively small. The magnetic attraction generated between the valve-opening core 4 and the valve-opening core 4 can be kept high, which is advantageous for valve-opening responsiveness.

[0040]

The fuel injection device for an internal combustion engine according to the present invention generates a magnetic attraction force between a valve body for opening and closing an injection hole, a valve closing core, and the valve closing core and the valve body. The valve closing solenoid is provided, and the valve closing core is movable, and when the valve body does not close the injection hole even when the valve body abuts on the valve closing core due to the magnetic attraction force. It is adapted to move with the valve body to allow the valve body to close the injection hole. Thereby, even when a thermal expansion difference occurs between the fuel injection valve body and the valve body as in the related art, the valve body is prevented from abutting on the valve closing core when the valve is closed, thereby closing the valve by the valve body. It is not necessary to design a large gap between the valve element and the valve closing core at the time of valve closing in order to ensure that the valve element and the valve closing core are large at the time of valve opening in the present fuel injection device. The valve closing solenoid can generate a large magnetic attraction force, and the valve closing responsiveness can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fuel injection device for an internal combustion engine according to the present invention.

FIG. 2 is an enlarged sectional view of the vicinity of a movable member when the fuel injection device of FIG. 1 is closed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Top end part 1a ... Injection hole 2 ... Pipe member 3 ... Base end part 4 ... Valve opening core 5 ... Valve closing core 6 ... Movable member 6b ... First part 6c ... Second part 7 ... Valve member 10 ... Valve opening solenoid 11 ... Valve closing solenoid 15 ... Collar member

Claims (3)

[Claims] 1. A valve body for opening and closing an injection hole, a valve closing core, and a valve closing solenoid for generating a magnetic attractive force between the valve closing core and the valve body. The valve closing core is movable, and the valve body does not close the injection hole even when the valve body contacts the valve closing core due to the magnetic attraction force. A fuel injection device for an internal combustion engine, wherein the fuel injection device is moved together with the valve body to close the injection hole. 2. An urging means for urging the valve body in a valve closing direction, a valve opening core, and a valve opening for generating a magnetic attraction force between the valve opening core and the valve body. The fuel injection device for an internal combustion engine according to claim 1, further comprising a solenoid for use in the engine. 3. A projection is provided on at least one of the opposing surfaces of the valve body and the valve-closing core that oppose each other.
3. The fuel injection device for an internal combustion engine according to claim 1, wherein a contact area when the valve body contacts the valve closing core is reduced. 4.