JP2526085Y2 - Fuel injection nozzle - Google Patents

Description

[Detailed description of the invention]

[0001]

[Industrial applications]

[0002] The present invention relates to a fuel injection nozzle for injecting fuel into a combustion chamber from an injection hole exposed in the combustion chamber, for example.

[0003]

2. Description of the Related Art Conventionally, when an injection hole is formed at the tip of a nozzle body of a fuel injection nozzle, the injection hole is directly formed by drilling, electric discharge machining, or the like on the nozzle body, and the shape of the injection hole is also changed. Is limited to the shape perforated by the processing method. By the way, in the fuel injection nozzle, with respect to the injection hole formed at the nozzle tip, the injection hole diameter and the number of injection holes are:
This is a condition that greatly affects the combustion state, and the determination of these various conditions for the injection hole is an important factor for improving the engine performance in relation to the engine performance. Further, it is a conventionally known element that not only the injection hole diameter and the injection hole number but also the injection hole shape such as the shape and the injection hole angle have a great influence on the combustion. For example, by changing the shape of the injection hole of the fuel injection nozzle from a conventional circular shape to a deformed shape such as a square shape, the velocity distribution of the spray particles can be changed and the intake of air can be improved.

Therefore, in order to secure a spray pattern effective for combustion in the fuel injection nozzle, the injection hole as shown in FIG.
A nozzle having a seven is provided. As a method of forming the injection hole in the fuel injection nozzle into the irregular injection hole 37 which is not a circular hole, as shown in FIG. 13, the nozzle body 33 and the nozzle tip 31 at the nozzle tip are separately manufactured. Next, as shown by an arrow in FIG. 14, a deformed injection hole 37 having a predetermined shape is punched out at a predetermined position of the nozzle tip 31 by laser processing by a laser processing machine or electric discharge machining by an electric discharge machine. Then, the joining end face 34 of the nozzle body 33 and the joining end face 32 of the nozzle tip 31 are joined.

As a method of forming the above-described injection hole, there is, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2-67458. In the method of manufacturing a fuel injector for an internal combustion engine disclosed in the publication, in order to form each hole, first, a hole having a straight side is formed, and thereafter, a head and a head are formed. A machining electrode of an electrolytic corrosion method having a smaller shaft portion is inserted into the hole from outside the nozzle, and the inserted machining electrode is moved so as to draw a predetermined trajectory. Is a trajectory that causes the head of the inserted machining electrode to enlarge the inner end of the hole.

[0007] Alternatively, as a method of forming the nozzle hole in a modified shape, as shown in FIG. 15, there is provided a method of integrally molding a nozzle body and a nozzle tip with ceramics. In this integral molding using ceramics, when molding the green compact 35 of ceramics, the core 36 is buried in the nozzle body forming portion and the injection hole forming portion, and the core 36 is removed. It is a method of forming.

[0007]

However, when an injection hole is formed in a nozzle body of a fuel injection nozzle by laser processing with a laser processing machine, an appropriate shape can be obtained on a laser irradiation surface. Has a problem that it is difficult to form a predetermined injection hole on the opposite surface.
In particular, the injection hole has a fine shape other than a circular shape, that is, a tapered shape,
It has been extremely difficult to form an injection hole having an irregular shape such as a polygon by a conventional injection hole forming method. Further, when the shape of the injection hole is complicated, for example, when the needle valve seat portion side is an expanded shape, it is extremely difficult to process the injection hole.

In the method of forming a divided injection hole as shown in FIGS. 13 and 14, when the joining end face 34 of the nozzle body 33 and the joining end face 32 of the nozzle tip 31 are joined, a plunger sleeve for molding is used. It is difficult to accurately match the position with the sheet surface forming the joint end face, and even if each joint end face is post-processed, the degree of rubbing by grinding is limited, and modification of the shape by grinding the joint end face is not possible. Have difficulty.

[0009] Further, as shown in FIG. 15, in the case of forming a green compact 35 of ceramics using the core 36, the injection hole has a hole diameter, for example, 0.2 mm to 0.1 mm. Since the holes are very fine, precision is required to produce the core 36 for forming the injection hole and set the core 36 at a predetermined position, and it is difficult to form the injection hole.

The present applicant has developed a fuel injection nozzle as shown in FIGS. 8 and 9 as an example of a fuel injection nozzle which solves the above-mentioned problem.
-90738. The fuel injection nozzle is
The nozzle body 1 is a poppet covered orifice type having a zero suck volume, has a hole 11 formed therein, and has a plurality of injection holes 10 near a tip end thereof, and slides in the hole 11 of the nozzle body 1. a plurality of spiral nozzle hole 10 communicating with the rotatably fuel passage 16 and fuel passage 16 to the fitting to and central
And a valve 3 formed with The sign
Reference numeral 17 denotes a sealing surface.

The fuel injection nozzle includes a nozzle body 1 and
The nozzle 3 has a valve 3 which is vertically movably or slidably fitted in a hole 11 formed in a longitudinal direction of a center portion of an axial center formed in the nozzle body 1. In the fuel injection nozzle, a plurality of injection holes 10 are formed at an end of the nozzle body 1 so as to be spaced apart and extend in the radial direction. The protruding portion 1 formed at the tip of the valve 3 is provided on the tip end surface 15 of the nozzle body 1.
4 is configured to be abuttable. Valve 3
Slides vertically moved by the lift amount L ₂ with respect to the nozzle body 1. In the fuel injection nozzle, a fuel passage 16 is formed in the longitudinal direction of the axial center of the valve 3. Further, the valve 3 is formed with a plurality of fitting holes 19 having one end opened to the fuel passage 16 and the other end opened to the injection hole 10 side. An injection hole forming body 20 having a cylindrical shape or the like and having a spiral groove 22 formed on the outer peripheral surface is fitted into the fitting hole 19.
Therefore, if each injection hole forming body 20 is fitted into the fitting hole 19 of the valve 3, an injection hole composed of the spiral groove 22 is formed between the inner surface of the fitting hole 19 and the outer surface of the injection hole forming body 20. Is done.
By configuring the fuel injection nozzle as described above,
As shown in FIG. 11, if only the sliding movement lift L ₂ downwards the valve 3 relative to the nozzle body 1, the spiral grooves 22
Is aligned with the injection hole 10, and the fuel passes through the fuel passage 16.
From outside through the injection hole 10.

However, each of the fuel injection nozzles is
Since the sealing surface 17 between the valve 3 and the nozzle main body 1 is formed between the outer periphery of the valve 3 and the inner diameter forming the hole 11 of the nozzle main body 1, a good sealing structure cannot always be provided. .

Alternatively, as shown in FIGS. 10 and 11,
It is conceivable to configure the injection hole portion of the fuel injection nozzle. In the figure, in the fuel injection nozzle, the same components as those of the fuel injection nozzle are denoted by the same reference numerals, and overlapping description will be omitted. In the fuel injection nozzle, an opening 23 having a large diameter is formed in the nozzle body 1, and an injection hole 28 penetrating through the injection hole formation body 27 is formed in an injection hole formation body 27 fitted in the fitting hole 19.
Is formed. Also in such a fuel injection nozzle, similarly to the above-described fuel injection nozzle, the sealing surface 17 is located between the outer periphery of the valve 3 and the inner diameter forming the hole 11 of the nozzle body 1 and has the same problem.

An object of the present invention is to solve the above-mentioned problem, and in the above-described poppet covered orifice type fuel injection nozzle having a zero sack volume composed of a nozzle body and a valve, an injection hole is provided. The formed body is formed independently of the nozzle body and the valve, and the shape of the injection hole can be easily and reliably changed to a desired one such as a square shape or a tapered shape by expanding the range of shape selection in the formation of the injection hole. In particular, the valve seat formed on the end face of the nozzle body and the valve face formed on the hollow ring fitted to the valve constitute a sealing surface to provide a good seal between the nozzle body and the valve. providing a sealing structure is to provide a fuel injection nozzle which reduces the possible securing of HC, NO _X and the like in the exhaust gas of diesel engines to ensure good combustion.

[0015]

The present invention is configured as follows to achieve the above object. That is, the present invention is directed to a nozzle body having a hole extending in the axial direction and having a valve seat at the tip, a slidably fitted inside the hole of the nozzle body, and a fuel passage and the fuel in the center. A valve having a plurality of fitting holes communicating with the passage, a valve face fitted and fixed to the valve, disposed on a protruding portion protruding from a tip of the valve, and having an upper surface in contact with the valve seat of the nozzle body; A hollow ring provided with: a nozzle hole forming body fitted in the fitting hole of the valve; and the valve seat and the valve face formed in the nozzle hole forming body and slidingly moving the valve with respect to the nozzle body. And a fuel injection nozzle configured to communicate with a gap formed between the fuel injection nozzle and the fuel injection nozzle.

[0016]

The fuel injection nozzle according to the present invention is configured as described above and operates as follows. That is, in this fuel injection nozzle, a nozzle body was formed with a hole extending in the axial direction, a valve seat was formed on an end face, and a fuel passage and a plurality of fitting holes communicating with the fuel passage were formed in the center. A valve is slidably fitted in the hole of the nozzle body, and a hollow ring having a valve face abutting on the valve seat of the nozzle body is fitted and fixed to the valve, and fitted into the fitting hole. Since the injection hole formed through the combined injection hole forming body is configured to communicate with the opening formed between the valve seat and the valve face by sliding movement of the valve with respect to the nozzle body, The sealing surface between the valve and the nozzle body is between the valve seat and the valve face, and a good sealing structure can be provided.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel injection nozzle according to the present invention will be described below with reference to the drawings. 1 is a schematic sectional view showing one embodiment of the fuel injection nozzle, FIG. 2 is an enlarged sectional view of a main part showing a closed state of the fuel injection nozzle of FIG. 1, and FIG. 3 is an opening of the fuel injection nozzle of FIG. It is an expanded sectional view of an important section showing a state.

This fuel injection nozzle is a poppet covered orifice type nozzle having a spiral multi-injection hole with a zero sack volume, and can reduce HC in exhaust gas of a diesel engine. The fuel injection nozzle includes a holder 2 having a fuel passage 21 for introducing fuel supplied from a fuel injection pump in a longitudinal direction of a center portion of an axial center,
Vertically movable That sliding nozzle body 1 and fixed with screws 18 or the like to the lower end of the holder 2, the hole 11 formed in the longitudinal direction of the axis center portion formed in the nozzle body 1 with the lift amount L ₁ The valve 3 movably fitted therein, the retainer 4 fixed to the upper end of the valve 3, and the return spring 5 disposed between the retainer 4 and the washers 8, 9 disposed on the upper end surface of the nozzle body 1. Have. A seal 13 is interposed between the holder 2 and the nozzle body 1. Further, in order to limit the moving range i.e. lift L ₁ of the vertical movement of the valve 3 relative to the nozzle body 1, between the upper and bottom surfaces of the retainer 4 of the nozzle body 1, lift stopper 7
Is arranged.

In this fuel injection nozzle, a valve seat 24 is formed on the end surface of the nozzle body 1. A hollow ring 30 is fitted to the protrusion 14 formed at the tip of the valve 3. A valve face 25 is formed on the upper end surface of the hollow ring 30, and the valve face 25 is configured to be able to contact the valve seat 24 of the nozzle body 1. When the valve seat 24 and the valve face 25 come into contact with each other, a liquid-tight sealing state is provided between the nozzle body 1 and the valve 3. The valve 3 slides up and down with respect to the nozzle body 1, but a key 12 is inserted across both sides so as not to rotate in the rotation direction. In this fuel injection nozzle, a fuel passage 16 communicating with the fuel passage 21 of the holder 2 is formed in the longitudinal direction of the axial center of the valve 3.

By configuring the fuel injection nozzle as described above, the sealing surface 17 of the conventional fuel injection nozzle can be used.
What is shown in FIG. 9 or 11 between the inner peripheral surface of the nozzle main body 1 and the outer peripheral surface of the valve 3 is transferred to the end surface of the nozzle main body 1 and the upper surface of the hollow ring 30 to greatly improve the sealing performance. be able to. For example, when the injection holes of the fuel injection nozzle are arranged in the combustion chamber, external forces such as compressed air pressure and explosion pressure inside the combustion chamber act in a direction to move the valve 3 from below to above with respect to the nozzle body 1. Then, the upper surface of the hollow ring 30 and the end surface of the nozzle body 1 are pressed against each other by the external force, and the sealing surfaces are brought into more close contact with each other, thereby improving the sealing performance. Therefore, an improvement in the fuel sealability during the compression stroke and the explosion stroke of the engine can be expected.

In this fuel injection nozzle, the valve 3 has a fitting hole having one end opened to the fuel passage 16 and the other end opened to a gap 26 formed between the valve seat 24 and the valve face 25. 19 are formed. The size of the gap 26 is a gap determined by the required lift amount L ₁ of the valve 3. The fitting hole 19 has an injection hole forming body 20 having a cylindrical shape or the like.
Are fitted. A spiral groove 22 having a desired shape is formed in advance on the outer peripheral surface of the injection hole forming body 20. Alternatively, the nozzle hole forming body 20 can be made of ceramics or the like. In this case, the spiral groove 22 formed in the nozzle hole forming body 20 can be formed by molding instead of cutting.

Therefore, when each injection hole forming body 20 is fitted into the fitting hole 19 of the valve 3, a spiral injection hole is formed in the valve 3 (the injection hole forming body is different, but FIG. reference).
When the fuel passage 16 is drilled in the valve 3 after the injection hole forming body 20 is fitted in the fitting hole 19 of the valve 3, the fuel passage 16 and the injection hole spiral injection hole are in communication with each other (injection hole formation). Although the body is different, see FIG. 7). When the injection hole forming body 20 is fitted into the fitting hole 19, the injection hole forming body 20 is fixed to the valve 3 by press-fitting, shrink fitting, joining, or the like. Fit in a rotating state. Depending on the case, the outer shape of the injection hole forming body 20 may be formed in a polygonal shape, or a projection may be formed on the outer periphery of the injection hole forming body 20 so that the injection hole forming body 20 is not rotated with respect to the valve 3. Can be fitted.

In this case, if the diameter of the injection hole forming body 20 is made larger than the gap 26 formed between the valve seat 24 of the nozzle body 1 and the valve face 25 of the valve 3, the injection hole forming body 20 Does not occur even if an external force such as fuel pressure is applied. Also, the gap 26
, It is a matter of course that the fuel spray injected from the spiral nozzle holes formed in the injection hole formed body 20 collides, or to set the lift amount L ₁ so as to be larger so as not to interfere.

[0024] The fuel injection nozzle, with the structure described above, when the valve 3 in the axial direction by the lift amount L ₁ sliding movement relative to the nozzle body 1, a nozzle body 1
A gap 26 is formed between the valve seat 24 and the valve face 25 of the hollow ring 30. In this case, the lift amount L ₁ of the valve 3, the structure has a merit that extremely small as compared with the lift amount L ₂ shown in FIG. 9 or 11. When the gap 26 and the spiral injection hole formed by the spiral groove 22 of the injection hole forming body 20 and the fitting hole 19 are aligned, the fuel delivered from the fuel injection pump is supplied to the fuel passages 21 and 16, Spiral injection holes are formed in the injection holes, and then injected into the combustion chamber through the gaps 26 in an independent spray state for each injection hole. When the fuel is sprayed into the combustion chamber, a good spray state can be ensured, the exhaust gas emission characteristics are improved as compared with the case where a normal fuel injection nozzle is used, and HC and N in the exhaust gas are improved.
The concentration of O _X can be reduced.

Next, another embodiment of the fuel injection nozzle according to the present invention will be described with reference to FIGS. 4 and 5. FIG. This fuel injection nozzle has exactly the same configuration except that the shape of the injection hole forming body is different from that of the above fuel injection nozzle. Therefore, the same parts are denoted by the same reference numerals, and overlapping descriptions will be omitted. Omitted. The injection hole 6 is formed in the injection hole forming body 27 by a punching process using electric discharge machining, laser machining, or the like. Thus, the injection hole 6 itself can be formed in advance on the injection hole forming body 27 independent of the valve 3. Therefore, the injection hole 6 formed in the injection hole formation body 27 can be perforated from the side located inside, and injection holes of various shapes can be formed. Then, as shown in FIG. 6, when each injection hole forming body 27 is fitted into the fitting hole 19 of the valve 3, the injection hole 6 is formed in the valve 3 as shown in FIG. The technique for fitting the injection hole forming body 27 into the fitting hole 19 is the same as in the above embodiment.

The injection hole forming body 27 used in the fuel injection nozzle according to the present invention is shown in the figure because it has a plurality of injection holes 6 which are communicated with the fuel passage 16 and are formed in the valve 3 in the radial direction. Although not shown, a plurality of split plugs can be used. Grooves of various shapes are formed on the split surfaces of these split plugs, and the grooves can form the injection holes 6. For example, it is possible to easily form an injection hole having a shape in which the cross-sectional shape of the injection hole 6 has the same cross-sectional area along the axial direction and the size of the injection hole 6 is reduced and enlarged in the direction, and the flow of the injected fuel is made smooth and a good injection pattern Can be formed.

[0027]

The fuel injection nozzle according to the present invention is configured as described above and has the following effects. That is, the fuel injection nozzle has a nozzle body formed with a hole extending in the axial direction and having a valve seat at the tip, slidably fitted in the hole of the nozzle body, and a fuel passage in the center. A valve formed with a plurality of fitting holes communicating with the fuel passage, a valve fitted to the valve, disposed on a protruding portion protruding at a tip of the valve, and having an upper surface in contact with the valve seat of the nozzle body A hollow ring having a face, an injection hole forming body fitted into the fitting hole of the valve, and the valve seat formed through the injection hole forming body and slidingly moving the valve with respect to the nozzle body. Since it has an injection hole that is in communication with the opening formed between the valve face and the valve face,
The sealing surface between the nozzle body and the valve of the fuel injection nozzle is shifted to the valve seat which is the end surface of the nozzle body and the valve face which is the upper surface of the hollow ring, so that the sealing performance can be significantly improved. For example, when the injection holes of the fuel injection nozzle are arranged in the combustion chamber, external forces such as compressed air pressure and explosion pressure inside the combustion chamber act in a direction to move the valve from below to above, and the external force causes the hollow ring to move. Of the nozzle body and the end face of the nozzle body are pressed against each other, so that the sealing surface is more closely contacted, and the sealing performance is improved. Therefore, an improvement in the fuel sealability during the compression stroke and the explosion stroke of the engine can be expected. In addition, the required lift amount of the valve can be made smaller than that of the above-described prior art fuel injection nozzle, and the response of the valve operation at the time of fuel injection can be improved.

Also, the split plug forming the injection hole can be formed separately from the nozzle body.
If the injection hole forming body is made of ceramics or the like, the injection hole can be formed by molding instead of drilling, and the shape of the injection hole can be changed. It can also be formed in irregularly shaped injection holes of various shapes.

Further, the injection hole forming body is formed from a plurality of split plugs, a groove is formed in a divided surface of the split plug, and an injection hole is formed by the groove in a state where the split surfaces of the split plug are aligned. By simply forming a groove in the split plug, a modified injection hole having a desired shape can be formed. For example, it is possible to easily form an injection hole having a shape in which the cross-sectional shape of the injection hole has the same cross-sectional area along the axial direction and reduces and expands the cross-sectional area in the same direction. Can be secured.

Then, the fuel spray is injected from the deformed injection hole into the combustion chamber, and a good spray characteristic is ensured.
C, to reduce the concentration of NO _x, yet the number of the injection holes can improve the combustion characteristics with respect to the combustion chamber of a broader shape by forming to conform the size or the like to the shape of the combustion chamber. Moreover,
The opening and the injection hole can be accurately brought into communication with each other by a simple sliding movement. Accordingly, the spray characteristics of the fuel injection nozzle, spray angle, it becomes possible to configure a shape that can ensure a low spray penetration, NO _x in the exhaust gas
Combustion characteristics can be improved for a combustion chamber having a wider shape by reducing the concentration and forming the number, size, and the like of the injection holes in conformity with the shape of the combustion chamber. Moreover, the range of fuel injection nozzles that can be selected as a combustion mode is widened,
The degree of freedom in design can be improved. This fuel injection nozzle is
As described above, the nozzle body, valve and hollow ring
Since they are easy to process,
In addition, a material suitable for the seal can be used.
It can be adjusted to the optimal lift amount according to the shape of the combustion chamber
it can.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a fuel injection nozzle according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part showing an embodiment of the fuel injection nozzle of FIG. 1 and showing a closed state of an injection hole.

FIG. 3 is an enlarged sectional view of a main part showing an opened state of an injection hole of the fuel injection nozzle of FIG. 2;

FIG. 4 is an enlarged sectional view of a main part showing another embodiment of the fuel injection nozzle according to the present invention, showing a closed state of the injection hole.

FIG. 5 is an enlarged sectional view of a main part showing an opened state of an injection hole of the fuel injection nozzle of FIG. 4;

FIG. 6 is an explanatory perspective view showing a step of incorporating an injection hole forming body into a valve in the fuel injection nozzle.

FIG. 7 is an explanatory perspective view showing a state in which an injection hole forming body is incorporated in a valve in the fuel injection nozzle of FIG. 6;

FIG. 8 is an enlarged sectional view of an essential part showing an example of a fuel injection nozzle of the prior art, showing a closed state of an injection hole.

9 is an enlarged cross-sectional view of a main part of the fuel injection nozzle shown in FIG. 8, showing an injection hole opened.

FIG. 10 shows another example of a prior art fuel injection nozzle;
It is an expanded sectional view of an important section showing a closed state of an injection hole.

11 is an enlarged cross-sectional view of a main part of the fuel injection nozzle of FIG. 10 showing an opened state of an injection hole.

FIG. 12 is a cross-sectional view illustrating an example of an injection hole in a conventional fuel injection nozzle.

FIG. 13 is a cross-sectional view showing another example of the manufacturing process of the conventional fuel injection nozzle.

14 is a cross-sectional view illustrating an example of a manufacturing process of an injection hole in the fuel injection nozzle of FIG.

FIG. 15 is a cross-sectional view showing still another example of the manufacturing process of the conventional fuel injection nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle main body 3 Valve 6 Injection hole 11 Hole 14 Protrusion 16 Fuel passage 19 Fitting hole 20 Injection hole forming body 22 Spiral groove (injection hole) 24 Valve seat 25 Valve face 26 Gap 27 Injection hole forming body 30 Hollow ring

Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location F02M 61/18 360 F02M 61/18 360D

Claims (1)

(57) [Scope of request for utility model registration] 1. A nozzle body having a hole extending in an axial direction and having a valve seat at a tip thereof, a nozzle slidably fitted in the hole of the nozzle body, and a fuel passage and a fuel passage in the center. A valve formed with a plurality of fitting holes communicating with the valve, a valve face fitted and fixed to the valve, disposed on a protruding portion protruding from the distal end of the valve, and contacting the valve seat of the nozzle body on the upper surface. A hollow ring provided, an injection hole forming body fitted in the fitting hole of the valve, and the valve seat and the valve face formed by sliding movement of the valve with respect to the nozzle body formed in the injection hole forming body. A fuel injection nozzle having an injection hole communicating with a gap formed between the fuel injection nozzle and the fuel injection nozzle.