JP2527677Y2 - 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.
Are 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. 9, the nozzle body 33 and the nozzle tip 31 at the nozzle tip are manufactured separately. Next, as shown by an arrow in FIG. 10, a deformed injection hole 37 having a predetermined shape is formed at a predetermined position of the nozzle tip 31 by laser processing by a laser processing machine or electric discharge processing by an electric discharge machine, This is a method of joining the joining end face 34 of the nozzle body 33 and the joining end face 32 of the nozzle tip 32.

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. 11, a method of integrally forming a nozzle body and a nozzle tip with ceramics is provided. 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.

[0008] In the split type injection hole forming method shown in FIG. 9, the joint end face 34 of the nozzle body 33 and the nozzle tip 31
It is difficult to accurately match the position of the plunger sleeve for molding with the sheet surface forming the joint end surface when joining the joint end surfaces 32 of the above, and even if each joint end surface is post-processed, it is difficult to perform polishing. The rubbing is the limit, and it is difficult to correct the shape by grinding the joint end face.

[0009] As shown in FIG. 11, when a ceramic powder compact 35 is formed using a 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 manufacture the core 36 for forming the injection hole and set the core 36 at a predetermined position, and it is difficult to form the hole.

Further, the present applicant has developed a fuel injection nozzle having a configuration for improving the spray trajectory, and filed an application as Japanese Utility Model Application No. 2-90738 before filing the application of this application. The fuel injection nozzle includes a nozzle body having a hole formed therein and having a plurality of openings near a tip end thereof, slidably fitted in the hole of the nozzle body, and having a fuel passage and a fuel passage in the center. And a valve having a plurality of injection holes communicating with the valve. The poppet covered orifice type has a sack volume of zero.

The above-mentioned poppet covered orifice type fuel injection nozzle will be outlined with reference to FIGS. 5, 6 and 7. FIG.
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, and a nozzle body fixed to a lower end of the holder 2 by a screw 22 or the like. 1. A valve 3, which is vertically movably fitted in a hole 11 formed in a longitudinal direction of a center portion of an axial center formed in the nozzle body 1, a retainer 4 fixed to an upper end of the valve 3, and a retainer 4 and a nozzle. A return spring 5 is disposed between the main body 1 and washers 8 and 9 disposed on the upper end surface. A seal member 13 is interposed between the holder 2 and the nozzle body 1. Further, in order to limit the vertical movement range of the valve 3 with respect to the nozzle body 1, that is, the lift amount L, the upper end face of the nozzle body 1 and the retainer 4
A lift stopper 7 is disposed between the lower end surface of the lift stopper 7 and the lower end surface.

In the above-described fuel injection nozzle, a plurality of injection holes 10 extending in the radial direction are formed in the vicinity of the tip end of the nozzle body 1 so as to be spaced apart in the circumferential direction. Further, the distal end surface 15 of the nozzle main body 1 is configured such that a protruding portion 14 formed at the distal end of the valve 3 can come into contact with the distal end surface 15. The valve 3 slides vertically 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 the 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 central portion of the axis of the valve 3. Further, the valve 3 is provided with a plurality of spiral passages having one end opened to the fuel passage 16 and the other end formed to be aligned with the injection hole 10.

These spiral passages communicate with a fuel passage 16 and a plurality of fitting holes 18 formed in the valve 3 in a radial direction.
Is formed by fitting a circular member 6 having a spiral groove 17 formed on the outer peripheral surface. In order to fix the circular member 6 to the hole 18 of the valve 3, the circular member 6 can be shrink-fitted to the valve 3 and joined by bonding or the like. As shown in FIG. 7, the fuel injection nozzle has a spiral passage formed by the spiral groove 17 by the sliding movement of the valve 3 downward with respect to the nozzle body 1 and an injection hole formed in the nozzle body 1 as shown in FIG. 10 is in a matching state. In this fuel injection nozzle, as shown in FIG. 6, the upward movement of the valve 3 with respect to the nozzle body 1 causes the spiral groove 17 and the injection hole 10 formed in the nozzle body 1 to be in a non-aligned state.

With respect to the downward movement of the valve 3, the fuel pressure supplied from the fuel injection pump is applied to the upper end surface 1 of the valve 3.
9 and the upper end surface 20 of the retainer 4 fixed to the valve 3, the fuel pressure becomes larger than the set load of the return spring 5, so that the valve 3 is attached to the nozzle body 1 against the spring force of the return spring 5. Move downward. For the upward movement of the valve 3,
When the fuel pressure supplied from the fuel injection pump applied to the upper end surface 19 of the valve 3 and the upper end surface 20 of the retainer 4 fixed to the valve 3 is released, the valve 3 is moved by the spring force of the return spring 5 to the nozzle body. 1, the protrusion 14 of the valve 3 comes into contact with the lower end surface of the nozzle body 1.

The fuel injection nozzle has the above-described configuration, and the spiral groove 17 and the injection hole 10 are aligned with each other.
The fuel delivered from the fuel injection pump is supplied to the fuel passage 2
The fuel is injected into the combustion chamber through the spiral grooves 17, 17, and then through the injection holes 10 in a spray state that is independently turned for each injection hole 10. When the fuel itself is sprayed to the outside in a swirled state, the fuel is sprayed for each injection hole 10 with a spray characteristic of a large spray angle and a low spray penetration force. by providing the like in consideration, it can ensure good atomization state adapted to the wider shape of the combustion chamber, turned into good exhaust gas discharged properties than with conventional fuel injection nozzle, of the NO _X in the exhaust gas The concentration can be reduced.

An object of the present invention is to solve the above-mentioned problem. In a poppet covered orifice type fuel injection nozzle having a zero suck volume, an injection hole forming body is provided independently of a nozzle body and a valve. It is possible to easily and surely form the injection hole shape into a desired irregular injection hole such as a square shape, a tapered shape, etc. The nozzle hole forming body is incorporated in a cassette, and the nozzle hole forming body is configured independently of the valve, so that the alignment between the opening of the nozzle body and the nozzle hole formed in the nozzle hole forming body can be easily achieved. In addition, it is possible to prevent the occurrence of fuel leakage, to secure good combustion, and to realize HC and NO in exhaust gas of a diesel engine.
An object of the present invention is to provide a fuel injection nozzle capable of ensuring reduction of _{X and the} like.

[0017]

The present invention is configured as follows to achieve the above object. That is, the present invention provides a nozzle body having a hole formed therein and having a circumferential injection hole communicating with the hole near the distal end, a nozzle body slidably fitted in the hole in the nozzle body, and a shaft. A valve body formed in a circumferential direction of a cylindrical portion formed at an end portion with a fuel passage in an axial direction and having a long hole which can be aligned with the injection hole, a plurality of valve bodies fitted and fixed in the cylindrical portion and communicating with the long hole; The present invention relates to a fuel injection nozzle comprising a cassette having an injection hole, and a fixing plug which is fixed to the distal end of the cylindrical portion in contact with the cassette and has a projecting portion capable of abutting the end face of the nozzle body.

Further, the cassette in the fuel injection nozzle has a cassette body having a fuel passage formed in the center thereof and a plurality of fitting holes communicating with the fuel passage, and is fitted in the fitting hole of the cassette body. It comprises a nozzle hole forming body having a nozzle hole.

In this fuel injection nozzle, the cassette is made of ceramic and has a fuel passage in the axial direction and a plurality of injection holes communicating with the fuel passage.

[0020]

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, the valve body is slidably fitted in a hole of the nozzle body having a circumferential opening, and the elongated hole is formed in the circumferential direction of the cylindrical portion extending to the end of the valve body. Since the cassette having the injection hole is formed so as to be aligned with the opening of the nozzle body, and the cassette having the injection hole is fitted and fixed to the cylindrical portion, the cassette can be fixed to the valve body after the injection hole is formed, and the injection hole can be formed in various shapes. In particular, since only the cassette is set in the valve body, the positioning or alignment between the injection hole and the opening of the nozzle body can be performed extremely easily.
Moreover, even if the cassette having the injection holes is made of ceramics or the like, there is no problem such as a fuel leak due to thermal expansion due to dissimilar materials.

[0021]

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. FIG. 1 is a schematic sectional view showing an embodiment of the fuel injection nozzle and showing a closed state of the injection hole, FIG. 2 is a schematic sectional view showing an open state of the injection hole in the fuel injection nozzle of FIG. 1, and FIG. It is a perspective view which shows the cassette of the fuel injection nozzle of FIG. This fuel injection nozzle has the same configuration as the fuel injection nozzle shown in FIG. 5 except that the structure of the injection hole portion is different. The description of the operation will be omitted.

The fuel injection nozzle has a nozzle body 1 having a plurality of circumferential injection holes 10 formed with a hole 11 and communicating with the hole 11 in the vicinity of the tip, and the inside of the hole 11 of the nozzle body 1. The valve body 3 is slidably fitted with the valve body 3. The valve body 3 has a cylindrical portion 23 formed at the tip end in an integrated structure. In the circumferential direction of the cylindrical portion 23, a plurality of long holes 24 that can be aligned with the injection holes 10 are formed. A cassette 25 is fitted and fixed in the cylindrical portion 23. The cassette 25 has a fitting hole 18 into which the injection hole forming body 6 is fitted. A spiral groove 1 is provided on the outer periphery in the longitudinal direction of the injection hole forming body 6.
7 are formed. The spiral groove 17 forms a spiral injection hole by fitting the injection hole forming body 6 into the fitting hole 18 of the cassette 25. This cassette 25 is inserted into the cylinder 2
In the case of fitting into 3, the spiral injection hole formed by the spiral groove 17 is positioned so as to communicate with the long hole 24 of the cylindrical portion 23 and fixed by brazing or the like. These spiral nozzles
Fuel passage 1 formed axially at the center of valve body 2
It communicates with 6. Further, a fixing plug 27 having a protruding portion 14 that can contact the end face 15 of the nozzle body 1 is fixed to the distal end portion of the cylindrical portion 23 in a state of being in contact with the cassette 25.

When the injection hole forming member 6 is fitted into the fitting hole 18, the injection hole forming member 6 is press-fitted, shrink-fitted, joined or the like.
Is fixed to the valve body 3, and the injection hole forming body 6 is
In a non-rotational state. Depending on the case, the outer shape of the injection hole forming body 6 may be formed in a polygonal shape, or a projection may be formed on the outer periphery of the injection hole forming body 6 so that the injection hole forming body 6 is not rotated with respect to the valve body 3. It can also fit in the state.

In this case, whether the diameter of the injection hole forming body 6 is larger than the diameter of the long hole 24 formed in the valve body 3 or
Alternatively, any part of the outer shape of the injection hole forming body 6 is
When the injection hole forming body 6 is formed to have a diameter larger than the diameter of the nozzle hole, the phenomenon that the injection hole forming body 6 jumps out of the long hole 24 does not occur even when an external force such as fuel pressure is applied. In addition, the diameters of the long holes 24 and the injection holes 10 are formed so large that the fuel spray injected from the injection holes formed in the injection hole forming body 6 does not collide or interfere with each other.

FIG. 4 shows another embodiment of the cassette incorporated in the fuel injection nozzle according to the present invention.
The cassette 25 in this embodiment has a fuel passage 1 in the center.
A plurality of injection holes 26 communicating with the fuel passage 6 and the fuel passage 16 are formed. The cassette 25 is manufactured by using a ceramic powder, forming a compact having injection holes by a method such as powder pressing or slip casting, and firing the compact. Accordingly, the injection holes 26 formed in the cassette 25 can be formed in various shapes of irregular injection holes. The structure for fitting and fixing the cassette 25 to the valve main body 2 is the same as that of the above-described embodiment, and a detailed description thereof will be omitted.

Further, the injection hole forming body 6 used in the fuel injection nozzle according to the present invention is shown in the figure because it forms a plurality of injection holes communicating with the fuel passage 16 and formed in the valve body 3 in the radial direction. Although not shown, a plurality of split plugs can be aligned. Grooves of various shapes are formed on the split surfaces of these split plugs, and the grooves can form an injection hole.

In this fuel injection nozzle, the valve body 3 is slidably moved in the axial direction by the lift amount L with respect to the nozzle body 1 due to the above-described structure, so that the injection hole 10 of the nozzle body 1 and the oblong hole 24 of the valve body 3 are formed. When the spiral injection hole or injection hole 26 formed in the cassette 25 is aligned with the fuel, the fuel delivered from the fuel injection pump is supplied to the fuel passage 16, the spiral injection hole or injection hole 26 formed in the modified injection hole, and then Through the long holes 24, the fuel is independently sprayed into the combustion chamber from the opening 10 for each injection hole. When the fuel is sprayed into the combustion chamber, a good spray state can be ensured, and the exhaust gas emission characteristics are improved as compared with a case where a normal fuel injection nozzle is used.
It is possible to reduce the concentration of NO _X.

[0028]

The fuel injection nozzle according to the present invention is configured as described above and has the following effects. That is, this fuel injection nozzle is provided with a nozzle body having a circumferential injection hole communicating with the hole, slidably fitted in the hole of the nozzle body, and fitted to the fuel passage and the end in the axial direction. A valve body formed in a circumferential direction of the formed cylindrical portion and having an elongated hole capable of being aligned with the injection hole, a cassette having a plurality of injection holes fitted and fixed to the cylindrical portion and communicating with the elongated hole; Since it is constituted by the fixing plug fixed to the tip of the cylindrical portion in a state of being in contact with the cassette, the injection holes and the elongated holes can be very easily aligned with the injection holes of the nozzle body. Further, the cassette forming the injection hole can be formed separately from the valve main body and the nozzle main body. Therefore, the injection holes formed in the cassette can be formed into a desired shape by, for example, punching out the injection holes by electric discharge machining, laser machining, or the like, or when the cassette is manufactured from ceramics or the like, The injection hole can be formed by molding instead of drilling, and it is easy to form the injection hole into variously shaped injection holes.
Moreover, even if the cassette having the injection holes is made of ceramics or the like, the end portion can be sealed with the fixing plug, so that even if a gap or the like is generated due to thermal expansion between different materials, there is no problem such as fuel leakage. Does not occur.

In the fuel injection nozzle, a cassette main body having a cassette formed at the center thereof with a fuel passage and a plurality of fitting holes communicating with the fuel passage, and fitted in the fitting hole of the cassette body; Since the injection hole forming body formed with the injection hole communicating with the long hole formed in the circumferential direction of the cylindrical portion, the injection hole can be formed independently of the injection hole forming body as a separate body, The hole can be easily formed in a modified injection hole such as a spiral shape. Therefore, by forming the injection holes as odd-shaped injection holes, the spray characteristics can be improved, and the spray pattern sprayed from the injection holes can be obtained with a large spray angle, a pattern such as a flattened spray shape, and the like. Can be improved.

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, the cross-sectional shape of the injection hole has the same cross-sectional area along the axial direction and is reduced in the direction,
An enlarged injection hole can be easily formed, and the flow of injected fuel can be made smooth to ensure a favorable injection pattern.

Further, in this fuel injection nozzle, the cassette can be manufactured from ceramics, and the injection hole can be easily formed in a modified injection hole. In addition, since the fuel injection nozzle has the above-described structure, even if the cassette is made of ceramics, a gap is not generated and fuel does not leak from the gap.

Therefore, regarding this fuel injection nozzle,
The fuel spray is injected into the combustion chamber from the foreign-shaped nozzle hole, HC in the exhaust gas to ensure good spray characteristics, to reduce the NO _X concentration, yet fit the number of nozzle holes, the size, etc. in the shape of the combustion chamber The combustion characteristics can be improved for a combustion chamber having a wider shape. In addition, the injection hole of the nozzle body and the injection hole and the elongated hole of the cassette can be accurately adjusted to a communicating state by a simple operation. Therefore, it is also possible to configure the spray characteristics of the fuel injection nozzle into a shape that can secure a spray angle and a low spray penetration force,
It can be reduced concentration of NO _X in the exhaust gas, yet can improve the combustion characteristics with respect to the combustion chamber of a broader shape by forming to conform the number of the injection holes, the size, etc. in the shape of the combustion chamber. In addition, the shape of the injection hole has a wide range that can be selected as the combustion mode of the fuel injection nozzle, and the degree of freedom in design can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a main part showing an embodiment of a fuel injection nozzle according to the present invention and showing a closed state of an injection hole.

FIG. 2 is a schematic sectional view of a main part showing an open state of the fuel injection nozzle of FIG. 1;

FIG. 3 is a perspective view showing one embodiment of a cassette incorporated in a valve body of the fuel injection nozzle of FIG. 1;

FIG. 4 is a perspective view showing another embodiment of the cassette incorporated in the valve body in the fuel injection nozzle of FIG. 1;

FIG. 5 is a schematic sectional view showing an example of a fuel injection nozzle according to the prior art.

FIG. 6 is an enlarged sectional view showing a closed state of an injection hole in the fuel injection nozzle of FIG. 5;

FIG. 7 is an enlarged sectional view showing an opened state of an injection hole in the fuel injection nozzle of FIG. 5;

FIG. 8 is a sectional view showing an example of an injection hole in a conventional fuel injection nozzle.

FIG. 9 is a cross-sectional view showing another example of the manufacturing process of the conventional fuel injection nozzle.

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

FIG. 11 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 main body 6 Injection hole forming body 10 Injection hole 11 Hole part 14 Projection part 16 Fuel passage 17 Spiral groove (injection hole) 18 Fitting hole 23 Tube part 24 Long hole 25 Cassette 26 Injection hole 27 Fixing plug

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location F02M 61/18 350 F02M 61/18 350D 360 360D

Claims (3)

(57) [Scope of request for utility model registration] 1. A nozzle body having a hole formed therein and having a circumferential injection hole communicating with the hole near a tip end thereof, an axial center fitted slidably in the hole of the nozzle body. Main body having a long hole formed in a circumferential direction of a cylindrical portion formed at an end portion and a fuel passage in a direction, and capable of being aligned with the injection hole, a plurality of fuel injection fittingly fixed to the cylindrical portion and communicating with the long hole. A fuel injection nozzle comprising: a cassette having a hole; and a fixed plug having a projection fixed to a tip of the cylindrical portion in contact with the cassette and capable of contacting an end surface of the nozzle body. 2. A cassette main body having a fuel passage formed at a center thereof and a plurality of fitting holes communicating with the fuel passage, and the injection hole formed by fitting into the fitting hole of the cassette body. 2. The fuel injection nozzle according to claim 1, comprising an injection hole forming body. 3. The fuel injection nozzle according to claim 1, wherein the cassette is made of ceramics, and has a fuel passage in an axial direction and a plurality of injection holes communicating with the fuel passage.