JPS6069261A - Fuel injection valve for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the reliability of a needle valve lift amount detector by a method wherein a photoconductive means is provided in the fuel injection valve and light, reflected from a direction different from the moving direction of a moving member, is projected into the light receiving end face thereof. CONSTITUTION:A needle valve 3 moves upwardly against a spring 8 when it receives fuel oil pressure in an oil reservoir 10 and moves downwardly to close the valve when the supply of high-pressure oil is stopped. In this case, a rod 15 moves together with and by the same amount of the movement of the needle valve 3 and a relative motion is caused between the bundle 18 of optical fibers and the tip end of the rod 15 in accordancd with the lifting motion of the needle valve 3. The bundle 18 of the optical fibers project parallel beams from a light source from the sidewise direction against the tip end of the rod 15 through the bundle 22 of optical fibers, receives the light of reflection, having a strength in accordance with the amount of lift of the needle valve from the end facd 20 to introduce it into a photoelectric converter through the bundle 21 of optical fibers and outputs the amount of lift as an electric signal. According to this method, the resistance to vibration of the valve may be improved, the length of gap between the moving member and the light receiving end of the photoconduction means may be adjusted easily and the reliability of the valve may be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection valve for an internal combustion engine that can detect the amount of displacement of a needle valve.

In order to electronically control the operating state of an internal combustion engine, various fuel injection valves for internal combustion engines have been proposed that are equipped with a detector for detecting the amount of displacement of a needle valve.

As one of this type of detector, a fuel injection valve has been proposed in which a needle valve and a nozzle constitute a mechanical switch (Japanese Patent Publication No. 55-50188). In this fuel injection valve, the electrical resistance between the needle valve and the body is zero when the injection nozzle is closed, but when the injection nozzle is open, the electrical resistance between the needle valve and the body is zero. This takes advantage of the fact that since there is a film of fuel oil between the two, the value becomes several ohms. However, a detector using such a mechanical switch has a problem in that it is somewhat unreliable.

In addition to the switching type detector described above, an iron core is provided at the tip of the pressing member that moves with the needle valve, and a coil consisting of a primary winding and a secondary winding through which the iron core is inserted is inserted into the valve body. The coil and iron core constitute a differential transformer, and 2
Next, a detector is installed to extract a voltage signal according to the position of the needle valve from the winding, and a search coil is installed at the tip of the fixed member opposite to the tip of the suppressing member, to detect the eddy current generated by the movement of the suppressing member. A detector that detects the amount of displacement of the needle valve by a search coil, or a piezoelectric detector using a piezoelectric element, etc. are used.

However, the above-mentioned conventional detector has the disadvantage that it cannot withstand long-term use because the winding or wiring is easily broken due to vibration and heat caused by the operation of the internal combustion engine.

Therefore, an object of the present invention is to provide a fuel injection system for an internal combustion engine, which is equipped with a highly reliable needle valve lift amount detector that is resistant to vibrations and heat effects caused by the operation of the internal combustion engine and can withstand long-term use. The purpose is to provide a valve.

The structure of the fuel injection valve for an internal combustion engine according to the present invention includes a first light-conducting means that projects light from a light source onto a moving member that moves with the movement of the needle valve, and a first light-conducting means that projects light from a light source onto a moving member that moves as the needle valve moves;
and a second light-conducting means that guides the light to the electrical conversion means, and reflected light from a direction different from the moving direction of the moving member enters the light-receiving end surface of the second light-conducting means. It has the following characteristics.

The light-receiving end surface of the second light-conducting means is arranged, for example, on the side of the movable member, and the opposing area between the side surface of the movable member and the light-receiving end surface is adjusted according to the amount by which the needle valve is lifted. The second light transmitting means and the movable member are positioned in this manner, and the intensity of the reflected light is reflected from a direction different from the direction of movement of the movable member to the light receiving end surface thereof in accordance with the lift amount of the needle valve. It may be configured such that the reflected light having an intensity corresponding to the lift amount of the needle valve is guided to the multi-light-to-electrical conversion means by the second light transmission means. By arranging the light-receiving end face on the side of the moving member so that reflected light from a direction different from the moving direction of the moving member is incident on the light-receiving end face, there is no fear that the moving member will come into contact with the second light-conducting means. Therefore, the gap length between the movable member and the light-receiving end of the second light-conducting means can be adjusted extremely easily, and the fixing and assembling of the second light-conducting means are improved. is significantly improved.

The first light conducting means may for example be an optical fiber, in which case the optical fiber may be a bundle of optical fibers or a single optical fiber. The same is true.

Hereinafter, the present invention will be explained in detail with reference to the illustrated embodiments.

FIG. 1 shows a two-part sectional view of a fuel injection valve for an internal combustion engine according to the invention.

A fuel injection valve 1 for an internal combustion engine includes a nozzle body 2, a needle valve 3 that moves in the axial direction within the nozzle body 2 to control an injection opening, a nozzle holder 4, and a nozzle body 2 and a nozzle holder/4 arranged in the middle. A sliding nut 6 that is fixed and integrated through a plate 5, a spring 8 housed in a spring chamber 7 in the nozzle holder 4, and a spring 8 provided in the head of the needle valve 3. It is separated from the spring tray 9 which is pressed downward. The nozzle body 2 is provided with an oil reservoir chamber 10, and the nozzle holder 4 is provided with an oil reservoir chamber 10.
An oil hole is drilled through it.

This oil passage hole is shown as oil passage hole 11 in Fig. 1.
, and the oil passage hole 12 formed in the intermediate plate 5 are in communication with each other. The nozzle holder 4 is provided with an oil passage hole 13 for guiding the fuel oil returning from the gap between the nozzle body 2 and the needle valve 3 to an oil tank (not shown).
The nozzle body 2 is provided with an oil passage hole 14 that communicates the oil passage hole 12 with the oil reservoir chamber 10 .

One end of a rod 15 is fixed to the upper end 9a of the spring tray 9, and the other end of the rod 15, which moves in accordance with the movement of the needle valve 8 in the axial direction, is connected to a hole formed above the spring chamber 7. 16 and is received within hole 16
The guide member 17 provided near the entrance of the rod 1
5 is slidably guided and supported. This guide member 17
The rod 15 is made of, for example, Duracon, oil-less metal, phosphor bronze, etc. The rod 15 is guided by the guide member 17 and moves back and forth in the axial direction according to the lift operation of the needle valve 3, so that the rod 15 and the guide Almost no wear occurs between the member 17 and the member 17.

In order to detect the above-mentioned movement of the rod 15 using an optical signal, an optical fiber bundle 18 is provided near the other end of the rod 15. A through hole 19 having an axis perpendicular to the axis of the hole 16 is bored in the nozzle holder 4, and the tip of the optical fiber bundle 18 is inserted into the through hole 19. An end face 20 of the bundle 18 faces the other end of the rod 15.

As shown in FIG. 2, the optical fiber bundle 18 has an open end, with an optical fiber bundle 21 constituting a light receiving side disposed inside and an optical fiber bundle 22 constituting a light emitting side disposed outside.

The optical fiber bundles 21 and 221 may each be a single optical fiber, and the optical fiber bundles 21 and 221 may each be a single optical fiber, and
The fiber bundle 21 may be a single optical fiber.

Returning to FIG. 1, the optical fiber bundle 18 is guided out of the nozzle holder 4 by passing through a guide 23 fixed to the exit of the through hole 19 by appropriate means, and the guide 23 is caulked halfway. As a result, the optical fiber bundle 18 is fixed to the nozzle holder 4. Therefore, the position of the optical fiber bundle 18 is fixed by the guide 23 and is oil-sealed.

On the other hand, as shown in FIG. 3, outside the main body of the fuel injection valve 1 for an internal combustion engine, the optical fiber bundle 18 is separated into optical fiber bundles 21 and 22, and the other end of the optical fiber bundle 22 is provided with a collimator lens, etc. A light source 24 that emits parallel light rays is fixed thereon so that the parallel light rays from the light source 24 can be irradiated onto the peripheral wall of the distal end of the rod 15 through the optical fiber bundle 22. A photoelectric converter 25 such as a phototransistor or a photomultiplier tube is fixed on the end side.

The positional relationship between the rod J5 and the optical fiber bundle 18 is the same as that of the needle valve 3.
When the rod 1 is seated on the corresponding valve seat and the injection valve is in the closed state, the rod 1 is in the positional relationship shown by the solid line in Figure 1.
5 does not face the end face 20 of the optical fiber bundle 18,
On the other hand, when the needle valve 3 is at full lift, its end surface 20 is configured to entirely face the circumferential surface of the end of the rod 14 (as shown by the dashed line in FIG. 1).

Therefore, when the needle valve 3 is not lifted at all, the light from the optical fiber bundle 22 will not be irradiated onto the outer circumferential surface of the rod 15, while the inner circumferential wall at the upper end of the hole 16 will not reflect the light, for example. It is painted black. Therefore, in this case, no reflected light is generated by the light irradiated from the optical fiber bundle 22, and the amount of light incident on the optical fiber bundle 21 is almost zero. For this reason, the inner circumferential wall at the upper end of the hole 16 may be subjected to, for example, a prunier treatment.

On the other hand, when the needle valve 3 lifts and the upper end outer circumferential surface of the rod 15, which is treated so as to press against the high reflectance surface, faces the end surface 20 of the optical fiber bundle 18, an amount of light corresponding to the opposing area is generated. The reflected light is guided to the light receiving surface of the photoelectric converter 25 via the optical fiber bundle 2I.

The output signal from the photoelectric converter 25 is supplied to an amplifier 26, and the level of the output signal from the amplifier 26 is displayed on a display 27.

To explain the operation of the fuel injection valve of the present invention configured as above, when high pressure fuel oil is supplied from a fuel injection pump (not shown), the high pressure fuel oil flows through the oil passage holes 11, 12 and 14 into the oil reservoir chamber. Guided by 10.

Therefore, the needle valve 3 receives the pressure of the fuel oil in the oil reservoir chamber 10, and
It moves upward in FIG. 1 against the pressure of the spring 8, and the internal combustion engine fuel injection valve 1 becomes open, and fuel oil is injected from the nozzle hole 28 of the nozzle body 2. On the other hand, when the supply of high-pressure fuel oil stops, the pressure inside the oil reservoir chamber 10 decreases,
The needle valve 3 is moved downward in FIG. 1 by the force of the spring 8, and the needle valve 3 comes into contact with the seat surface of the nozzle body 2, and the fuel injection valve for the internal combustion engine is in the closed state. Oil injection stops. At this time, the rod 15 moves in the same direction by the same amount as the needle valve 3 moves. Therefore, as described above, a relative movement occurs between the optical fiber bundle 18 and the tip of the rod 15 in accordance with the lift operation of the needle valve 3, and a strength corresponding to the lift amount of the needle valve 3 is generated from the optical fiber bundle 21. The reflected light signal can be extracted.

In this case, the end surface 2o of the optical fiber bundle 18 is arranged on the side of the rod 15, which is a moving body, and allows reflected light from a direction different from the advancing and retreating direction of the rod 15, that is, the direction of its axis, to enter the light receiving end surface 2o. With this structure, the distance between the optical fiber bundle 18 and the rod 15 can be easily adjusted, which has the excellent advantage of being easy to assemble and making the adjustment work extremely easy. .

In the above embodiment, the rod 15 is guided by the guide member 17, but the guide member 17 is not necessarily necessary, and is unnecessary when the rod 15 is guided by the nozzle holder 4. However, if it is desired that the vicinity of the tip of the rod 15 in the hole 16 be a dark area, a guide member 17 made of the above-mentioned material is provided in order to prevent the various substrates from being exposed due to wear caused by sliding of the rod 15. This is extremely effective.

In the above embodiment, the light from the optical fiber bundle 18 is projected onto the peripheral surface of the end of the rod 15, which has a flat upper end surface, and the lift of the needle valve 3, etc. is detected based on the intensity of this reflected light. As shown in FIG. 4, the upper end of the rod 15 is formed into a conical shape, and when the needle valve 3 is not lifted at all, it is out of sight from the fiber bundle 21, as shown by the dotted line, and the needle valve 3 As shown by the solid line, when the conical part is fully lifted, the conical part completely enters the field of view, and the maximum reflected light may be obtained. In this case, only the conical head of the rod 150 is used as a reflective surface, but the reflective surface includes chrome plating,
Aluminum vapor deposition or the like may be applied, or a diffused reflection surface may be used. If the reflective surface is a diffuse reflective surface, the light receiving range on the east side of the optical fiber will be expanded, making positioning adjustment easier.
This has the advantage that the reflected light becomes stronger.

Furthermore, the positional relationship between the end surface 20 of the optical fiber bundle 18 and the rod 15 is not limited to that shown in FIGS. 1 and 4,
As shown in FIG.
A part of the circumferential surface 15a is made into a high reflectance surface by, for example, chromium plating, and the other circumferential surface is made into a low reflectance surface by black painting or prunier treatment, etc., and depending on the lift amount of the needle valve 3. , the opposing area between the high reflectance surface 15a and the end face of the optical fiber bundle 18 may be changed.

In the case shown in FIGS. 1 and 5, the curved surface of the rod 15 is circular, but the tip of the rod 15 is formed to have a square cross section, so that the reflective surface of the rod 15 seen from the optical fiber bundle 18 is substantially It may be made to increase to.

If it is necessary to keep the reflective surface of the rod 15, which faces the end surface 20 of the optical fiber bundle 18, constant, the upper end of the rod 15 may have a rectangular cross section as shown in FIG.
By providing the guide member 40 having a guide hole corresponding to the outer shape of this rectangular portion in the hole 16, the predetermined reflective surface 15b of the rod 15 can always be opposed to the end surface 20 of the optical fiber bundle 18.

The strength of the reflected light detected by the optical fiber bundle 21 changes over time due to various reasons, but the lift amount of the needle valve 3, the injection amount Q, and the rotational speed N of the fuel injection pump are Since there is a certain relationship between them, this relationship between these three is stored in advance as mass data in a ROM, etc., and the true value of the lift amount is calculated based on this map. The intensity of the reflected light detected by the light 77471 bundle 21 can be corrected based on the data.

FIG. 7 shows a modification of the embodiment shown in FIG. In the fuel injection valve 31 shown in FIG. 7, a through hole 33 for guiding the optical fiber bundle 18 to the tip of the rod 32 is provided so as to be inclined so as to look into the head 32a of the rod 32 from diagonally above. The fuel injection valve 1 differs from the fuel injection valve 1 shown in FIG. 1 in that the head 32m of the rod 320 is formed in a conical shape. In FIG. 7, parts that are the same as those in FIG. 1 are given the same reference numerals, and explanations thereof will be omitted.

Another embodiment of the invention is shown in FIG. 8th
In the fuel injection valve 41 shown in the figure, a through hole 42 having an axis perpendicular to the axial direction of the needle valve 3 is formed in the intermediate plate 5 so as to look into the lower end surface of the spring receiver 9. 74719 bundles of light! A through hole 43 is formed in the nozzle holder 4 through which the nozzles 1i and 8- are inserted. The axis of the through hole 43 is substantially parallel to the axis of the nozzle holder 4 and communicates with a through hole 44 formed in the intermediate plate 5. The optical fiber bundle 18 is inserted into the through holes 43 and 44 from the outside of the nozzle holder 4, and the tip thereof is inserted into the through hole 44, and the end surface 20 of the optical fiber bundle 18 is inserted into the through hole 44. The inside of the through hole 42 is looked into from the inside. A prism 45 for optically connecting the through hole 42 and the through hole 44 is disposed in the through hole 4"3, which allows
When the light projected from the optical fiber bundle 18 enters the through hole 42, it is refracted toward the right in FIG. 8 and can reach the lower end 9b of the spring receiver 9. The light reflected from the lower end 9b of the spring receiver 9 follows the opposite optical path and reaches the end face 20 of the 5 bundles of optical fibers 18. In FIG. 8, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted. The surface of the lower end 9b of the spring tray 9 is plated with chrome, while the outer peripheral surface of the needle valve 3 and the inner peripheral surface of the intermediate plate 5 are painted black. The projected light is reflected only by the spring tray 9. The lower end of the spring tray 9 is
It is adjusted so that the facing state of the through hole 42 with the opening at one end changes according to the lift operation of the needle valve 3, and therefore,
Reflected light corresponding to the lift amount of the needle valve 3 is extracted via the optical fiber bundle 21.

According to such a configuration, there is no need to provide a rod for detecting the needle valve lift amount on the spring receiving plate 9, and the configuration becomes simple.

According to the present invention, as described above, it is only necessary to provide a light conductive means such as an optical fiber bundle in the fuel injection valve, and no electrical wiring is required. Since the arrangement is such that reflected light from a direction different from the moving direction of the moving member is incident on the light-receiving end surface of the light-conducting means, it is extremely easy to adjust the gap length between the moving member and the light-receiving end of the light-transmitting means. Assembling and adjustment can be performed with great ease, reliability can be improved, and assembly costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a fuel injection valve according to the present invention, FIG. 2 is a schematic diagram showing a cross section of an optical fiber bundle, FIG. 3 is a block diagram showing the configuration of a detector, and FIGS. FIG. 5 is an enlarged view of a main part showing a modification of the main part of the fuel injection valve shown in FIG. 1, and FIG. 6 is a schematic configuration showing the main part of a modification of the fuel injection valve shown in FIG. 7 are sectional views showing a modification of the fuel injection valve shown in FIG. 1, and FIG. 8 is a sectional view showing another embodiment of the fuel injection valve according to the present invention. DESCRIPTION OF SYMBOLS 1... Fuel injection valve, 2... Nozzle body, 3... Needle valve, 4... Nozzle holder, 15... Rod, 18,
21.22... Optical fiber bundle, 20... End face. Patent applicant: Diesel Kiki Co., Ltd. Agent: Patent attorney: Masatoshi Takano Figure 7: Unpublished! 'lR60-69261(7) Figure 8

Claims (1)

[Claims] 1. A first light conduction means that projects light from a light source onto a moving member that moves as the needle valve moves; and a second light conduction means that guides reflected light from the moving member to a light-to-electrical conversion means. A fuel injection valve for an internal combustion engine, characterized in that the fuel injection valve is configured such that reflected light from a direction different from the moving direction of the moving member enters the light receiving surface of the second light conducting means.