JP2003113760A - Fuel injection nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection nozzle capable of preventing any foreign matter from intruding to between a valve seat part and an abutting part and also a jet hole from clogging and promoting the fuel to be atomized. SOLUTION: A needle 21 of this fuel injection nozzle is furnished internally with a fuel passage 25 and also with a communication passage 26 to put the fuel passage 25 in communication with a fuel supply passage 14 through which the fuel is supplied and a through hole 27 to put the fuel passage 25 in communication with a fuel flow passage 19. The fuel having flowed into the fuel passage 25 via the communication passage 26 from the fuel supply passage 14 is supplied from the through hole 27 to the jet hole 12 via the fuel flow passage 19. Because the inside diameter of the through hole 27 is smaller than that of the jet hole 12, fine foreign matter likely to cause clogging of the jet hole 12 is removed by the through hole 27. This prevents fine foreign matters from intruding to between the valve seat 11a and abutting part 21a and the jet hole 12 from clogging.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an internal combustion engine (hereinafter,
An internal combustion engine is called an "engine." ) Fuel injection nozzle.

[0002]

2. Description of the Related Art Conventionally, a nozzle needle is reciprocally housed in a nozzle body, and a contact portion of the nozzle needle is seated on a valve seat portion formed on the nozzle body or is separated from the valve seat portion. As a result, a fuel injection nozzle of a fuel injection device that interrupts fuel injected from an injection hole is known.
Fuel injection nozzles are required to atomize fuel from the viewpoints of reducing fuel consumption of the engine, reducing NOx contained in exhaust gas, operating stability, and the like. As a means for promoting atomization of fuel, for example, reducing the inner diameter of the injection hole can be considered. However, if the inner diameter of the injection hole is made smaller, foreign matter contained in the fuel may enter the injection hole, and the injection hole may be clogged. Therefore, conventionally, a filter member such as an edge filter is installed in the inlet portion of the fuel injection device into which the fuel flows to collect and remove the foreign matter contained in the fuel.

[0003]

As described above, in order to atomize the fuel, if the inner diameter of the injection hole is made smaller than before, it is necessary for the filter member to collect and remove smaller foreign matter. It is necessary to reduce the clearance of the filter member in order to remove minute foreign matter. However, if the clearance of the filter member is reduced, the pressure loss of the fuel passing through the filter member increases, so that the fuel injection pressure decreases, and there is a problem that desired engine performance cannot be obtained.

Further, when a filter member is installed in the inlet portion, foreign matter generated inside the fuel injection nozzle, for example, foreign matter generated by cavitation or erosion of fuel generated between the nozzle body and the nozzle needle, is collected. I can't. Therefore, foreign matter may be caught between the valve seat portion and the contact portion, or the injection hole may be clogged.

Therefore, an object of the present invention is to provide a fuel injection nozzle which prevents foreign matter from entering between the valve seat portion and the abutment portion and clogging of the injection hole, and promotes atomization of fuel. It is in. Another object of the present invention is to provide a fuel injection nozzle which has a simple structure and removes minute foreign matters contained in fuel to promote atomization of the fuel.

[0006]

According to the fuel injection nozzle of the first aspect of the present invention, the fuel supplied from the fuel supply passage of the nozzle body is axially formed inside the nozzle needle. Flow into. The fuel that has flowed into the fuel passage flows out through the through hole into the fuel flow path and flows toward the inlet side of the injection hole. For example, by setting the inner diameter of the communication passage or the through hole to be smaller than the minimum diameter of the foreign matter that needs to be removed, minute foreign matter contained in the fuel can be collected by the communication passage or the through hole. Therefore, the foreign matter is removed near the injection hole,
Foreign matter does not enter between the valve seat portion and the contact portion, and the injection hole is not clogged. Therefore, the inner diameter of the injection hole can be reduced, and atomization of fuel can be promoted. Further, by forming a plurality of communication passages or through holes in the nozzle needle, the area where the fuel can flow is increased, and the pressure loss of the fuel can be reduced.

According to the fuel injection nozzle of the second or third aspect of the present invention, the nozzle needle has the bottom portion and the tubular portion which are integrally formed. Therefore, the number of parts can be reduced. According to the fuel injection nozzle of the fourth aspect of the present invention, the main body and the seat member are formed separately. For example, the fuel passage can be easily formed by forming the fuel passage in the main body and then installing the sheet member in the main body.

According to the fifth aspect of the fuel injection nozzle of the present invention, the main body and the lid member are formed separately. For example, the fuel passage can be easily formed by forming the fuel passage in the main body and then installing the lid member in the main body. According to the fuel injection nozzle of claim 6 of the present invention,
The inner diameter of the through hole is smaller than the inner diameter of the communication passage. Therefore, minute foreign matter contained in the fuel that cannot be removed by the communication passage can be collected by the through hole.

According to the seventh aspect of the fuel injection nozzle of the present invention, the inner diameter of the through hole is larger than the inner diameter of the communication passage. Therefore, minute foreign matter contained in the fuel can be collected in the communication passage. According to the fuel injection nozzle of the eighth aspect of the present invention, the inner diameter of either the through hole or the communication passage is smaller than the inner diameter of the injection hole. Therefore, the minute foreign matter contained in the fuel that causes the clogging of the injection hole is collected in the through hole or the communication passage before entering the injection hole. Therefore, it is possible to prevent the injection holes from being clogged.

According to the fuel injection nozzle of the tenth aspect of the present invention, the nozzle needle has the guide portion between the communication passage and the through hole. Since the guide part slides on the inner peripheral side of the nozzle body, the liquid-tightness of the sliding part is enhanced, and the fuel flowing from the fuel supply flows from the communication passage to the inlet side of the injection hole via the fuel passage and the through hole. Supplied. Therefore, it is possible to reduce the amount of fuel that directly flows into the inlet side of the injection hole via the sliding portion, and it is possible to more reliably collect minute foreign matter contained in the fuel.

According to the fuel injection nozzle of the eleventh aspect of the present invention, the filter member is installed on the fuel outlet side of the fuel reservoir formed between the nozzle body and the nozzle needle. The filter member collects minute foreign matter contained in the fuel. Therefore, it is only necessary to install the filter member in the fuel pool, and the structure can be simplified.
Further, minute foreign matters contained in the fuel that cause the clogging of the injection hole are removed by the filter member. Therefore, the inner diameter of the injection hole can be reduced, and atomization of the fuel can be promoted.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of embodiments showing the embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 2 shows a fuel injection device to which a fuel injection nozzle according to a first embodiment of the present invention is applied (hereinafter, the fuel injection device is referred to as an "injector"). Injector 1
Is mounted by being inserted into a cylinder head of an internal combustion engine (not shown), and injects fuel into each cylinder of the engine.

The injector 1 according to the first embodiment is applied to a common rail fuel injection system of a diesel engine. The injector 1 mainly includes a housing 2, a fuel injection nozzle 10, an electromagnetic drive unit 3 and a fuel inlet 4. The fuel injection nozzle 10 is installed on the side of the housing 2 opposite to the electromagnetic drive unit 3. The fuel injection nozzle 10 includes a nozzle body 11 and a nozzle needle 21 as shown in FIG. A nozzle hole 12 is formed near the tip of the nozzle body 11. Further, a valve seat portion 11a is formed on the inlet side of the injection hole 12 of the nozzle body 11. The nozzle needle 21 is the nozzle body 1
It is supported on the inner peripheral side of 1 so as to be capable of sliding back and forth in the axial direction.
The nozzle needle 21 is formed with an abutting portion 21a, and the abutting portion 21a can come into contact with the valve seat portion 11a formed on the inner peripheral side of the nozzle body 11. Abutting portion 21a
Is seated on the valve seat portion 11a, or the contact portion 21a is separated from the valve seat portion 11a, the fuel injection from the injection hole 12 is interrupted.

As shown in FIG. 2, a control piston 2a that abuts the nozzle needle 21 is housed on the inner peripheral side of the housing 2. On the inner peripheral side of the housing 2, a pressure control chamber (not shown) is formed on the side opposite to the nozzle needle of the control piston 2a. The fuel inlet 4 is installed in the pressure control chamber.
The high-pressure fuel supplied from is stored. The high-pressure fuel stored in the pressure control chamber urges the control piston 2a downward in FIG. When the control piston 2a is biased by the fuel, the nozzle needle 21 that contacts the control piston 2a is biased in the injection hole closing direction. That is, the abutting portion 21a of the nozzle needle 21 is biased in the direction to be seated on the valve seat portion 11a of the nozzle body 11.

The electromagnetic drive unit 3 is installed on the opposite side of the housing 2 from the fuel injection nozzle 10. Electromagnetic drive 3
Has an electromagnetic valve (not shown) that connects and disconnects the discharge of the fuel stored in the pressure control chamber. When the solenoid valve is opened and the fuel in the pressure control chamber is discharged, the pressure inside the pressure control chamber decreases and the force that urges the nozzle needle 21 in the nozzle hole closing direction decreases. The nozzle needle 21 is biased in the nozzle hole opening direction by the fuel pressure in the vicinity of the valve seat portion 11a rather than the force by which the nozzle needle 21 is biased in the nozzle hole closing direction by the pressure of the fuel in the pressure control chamber. The nozzle needle 21 lifts upward in FIG. When the nozzle needle 21 is lifted, the contact portion 21a is separated from the valve seat portion 11a, and the fuel is injected from the injection hole 12.

On the other hand, when the electromagnetic valve is closed and the discharge of fuel from the pressure control chamber is stopped, the pressure inside the pressure control chamber increases, and the force for urging the nozzle needle 21 in the injection hole closing direction increases. To do. Therefore, the nozzle needle 21 moves downward in FIG. 2, and when the contact portion 21a is seated on the valve seat portion 11a, the fuel injection from the injection hole 12 is stopped.

The fuel inlet 4 is formed integrally with the housing 2. The fuel inlet 4 is supplied with high-pressure fuel stored in a common rail (not shown) in a pressure-accumulated state. The high-pressure fuel supplied from the common rail is
It flows into the fuel inlet 4 from the fuel inlet 4 a and is supplied to the pressure control chamber and the fuel injection nozzle 10. A filter member (not shown) is installed in the fuel inlet 4 to remove relatively large foreign matter contained in the fuel.

Next, the fuel injection nozzle 10 will be described in detail. The fuel injection nozzle 10 includes the nozzle body 11 and the nozzle needle 21 as described above. As shown in FIG. 2, the fuel injection nozzle 10 is connected by a retaining nut 5 to the end of the housing 2 opposite to the electromagnetic drive unit 3. As shown in FIG. 1, the nozzle body 11 is formed in a substantially cylindrical shape, and inside thereof, a guide hole 13 for accommodating the nozzle needle 21 and a fuel supply passage 14 are formed. The fuel supply passage 14 communicates with a fuel passage 2b formed in the housing 2 shown in FIG. 1 and communicating with the fuel inlet 4. In addition, the nozzle body 11
Has a nozzle hole 12 formed at the end opposite to the housing 2. The injection hole 12 connects the inner peripheral surface and the outer peripheral surface of the nozzle body 11. The inner peripheral surface side of the injection hole 12 is opened to a sack portion 15 formed in the nozzle body 11.
The guide hole 13 is formed in the axial direction, and the fuel supply path 1
The fuel reservoir 16 communicates with the fuel tank 4 and the large diameter portion 17. A part of the inner wall of the nozzle body 11 forming the guide hole 13 is a sliding portion 13a that slidably supports the nozzle needle 21. At the end of the guide hole 13 on the injection hole 12 side,
A truncated cone surface 18 is connected to the truncated cone surface 18, and a substantially annular valve seat portion 11 a is formed on the truncated cone surface 18. Valve seat 11a
Are formed on the inlet side of the injection hole 12.

The nozzle needle 21 has a bottom portion 22 and a tubular portion 23, which are integrally formed, and a pin member 24. The bottom portion 22 has a truncated cone portion 2 as shown in FIG.
21 and the conical portion 222, the truncated cone portion 221
The connecting portion between the cone portion 222 and the conical portion 222 serves as an annular contact portion 21a. Note that FIG. 3 shows a state in which only the nozzle needle 21 is rotated by 90 ° in the circumferential direction from the state shown in FIG. Further, as shown in FIG. 1, the space surrounded by the inner peripheral surfaces of the bottom portion 22, the tubular portion 23 and the pin member 24 is a fuel passage 25
Is. The tubular portion 23 is formed in a substantially cylindrical shape,
It has a large diameter portion 231 and a small diameter portion 232. The outer diameter of the large diameter portion 231 is substantially the same as the inner diameter of the guide hole 13, and the outer peripheral surface of the large diameter portion 231 is the sliding portion 13a of the nozzle body 11.
Can be slid with. The outer diameter of the small diameter portion 232 is smaller than the inner diameter of the guide hole 13, and a gap is formed between the small diameter portion 232 and the inner peripheral surface of the nozzle body 11. This gap becomes the fuel flow path 19.

The tubular portion 23 is formed with a communication passage 26 and a through hole 27 which communicate the inner peripheral surface and the outer peripheral surface. The communication passage 26 and the through hole 27 are formed at two locations in the circumferential direction of the nozzle needle 21. The communication passage 26 is provided in the fuel pool 16
The fuel passage 25 and the fuel supply passage 14 are communicated with each other via. On the other hand, the through hole 27 connects the fuel passage 25 and the fuel flow passage 19. At the end of the tubular portion 23 opposite to the bottom portion 22,
A pin member 24 is installed. The outer diameter of the pin member 24 is substantially the same as the inner diameter of the tubular portion 23, and the pin member 24 is installed by, for example, press fitting. Bottom 22 of pin member 24
The end portion 24a on the opposite side to can contact the control piston 2a.

In the nozzle needle 21, for example, a hole serving as a fuel passage 25 is formed in a solid rod-shaped member having a truncated cone portion 221 and a cone portion 222 formed in a bottom portion 22, and a communication passage 26 communicating with the hole is formed. The through hole 27 is formed. Then, the pin member 24 is press-fitted into the hole serving as the fuel passage 25, so that the nozzle needle 21 as shown in FIG. 1 is formed.

The inner diameter of the through hole 27 is smaller than the inner diameter of the communication passage 26 and smaller than the inner diameter of the injection hole 12. By making the inner diameter of the through hole 27 smaller than the inner diameter of the injection hole 12, foreign matter larger than the inner diameter of the injection hole 12 is collected by the through hole 27. That is, foreign matter larger than the inner diameter of the injection hole 12, which causes the clogging of the injection hole 12, will not pass through the through hole 27.
Is reliably collected by. A plurality of through holes 27 are formed in the circumferential direction and the axial direction of the tubular portion 23. Therefore, even when the inner diameter of the through hole 27 is reduced as described above, the total area through which the fuel can flow is sufficiently secured, and the pressure loss of the fuel is reduced.

The fuel supplied from the fuel supply passage 14 passes through the fuel reservoir 16 and the communication passage 26, and the fuel passage 25.
Flow into. The fuel that has flowed into the fuel passage 25 passes through the through hole 27.
And flows out into the fuel flow path 19 and is supplied to the injection hole 12.

As described above, according to the fuel injection nozzle 10 of the first embodiment of the present invention, the injection hole included in the fuel is formed by the through hole 27 formed in the cylindrical portion 23 of the nozzle needle 21. It is possible to collect foreign matters larger than the inner diameter of 12. Therefore, the inner diameter of the injection hole 12 can be reduced, and atomization of fuel can be promoted. Further, since the foreign matter is collected in the through hole 27, it is possible to prevent the foreign matter contained in the fuel from entering between the valve seat portion 11a and the contact portion 21a. Therefore, the valve closing failure of the fuel injection nozzle 10 can be prevented. Further, since the foreign matters contained in the fuel are removed by the plurality of through holes 27 formed, it is not necessary to install a filter member having a small clearance in the fuel inlet 4 of the injector 1. Therefore, the pressure loss of the fuel can be reduced.

Further, in the first embodiment, the foreign matter contained in the fuel can be removed in the vicinity of the injection hole 12. Therefore, it is possible to remove foreign matter generated in the vicinity of the injection hole 12 that cannot be collected by the filter member installed in the fuel inlet 4 of the injector 1. Furthermore, in the first embodiment, the nozzle needle 21 is formed with the axial fuel passage 25, the communication passage 26 and the through hole 27 in the direction perpendicular to the axis, and thus the nozzle needle 21 can be easily processed.

(Second and Third Embodiments) FIG. 4 shows the fuel injection nozzles according to the second and third embodiments of the present invention.
And shown in FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. The second embodiment and the third embodiment are modifications of the first embodiment, and the structure of the nozzle needle is different from that of the first embodiment. The nozzle body is the same as in the first embodiment.

As shown in FIG. 4, in the fuel injection nozzle 30 of the second embodiment, the nozzle needle 31 is composed of a main body 32 and a seat member 33, and the main body 32 and the seat member 33 are formed separately. Has been done. The main body 32 is formed in a cylindrical shape having an integrally formed bottom portion 34. A fuel passage 35 is formed on the inner peripheral side of the main body 32. Further, the main body 32 is formed with a communication passage 36 and a through hole 37 that communicate with the fuel passage 35. Body 32
The bottom portion 34 is formed with a protruding portion 34a protruding toward the side opposite to the sheet member 33, and the protruding portion 34a corresponds to the pin member of the first embodiment. Further, the main body 32 has a large diameter portion 321 that slides on the inner peripheral surface of the nozzle body 11.

The sheet member 33 is installed at the end of the body 32 opposite to the bottom 34. The sheet member 33 is
The fuel passage 35 is formed in the main body by, for example, press fitting. The sheet member 33 includes the first cylindrical portion 33.
1, second cylindrical portion 332, truncated cone portion 333 and conical portion 3
34, the truncated cone 333 and the cone 33
The connecting portion with 4 is the contact portion 31a. First cylindrical portion 331
Are press-fitted into the inner peripheral side of the main body 32, that is, into the fuel passage 35. In the second embodiment, after the fuel passage 35, the communication passage 36, and the through hole 37 are formed in the main body 32, the seat member 33 is installed at the end of the main body 32 opposite to the bottom portion 34, so that the nozzle needle 31 Can be formed.

As shown in FIG. 5, in the fuel injection nozzle 40 of the third embodiment, the nozzle needle 41 is composed of a main body 42 and a lid member 43, and the main body 42 and the lid member 43 are formed separately. Has been done. The main body 42 is formed in a cylindrical shape having an integrally formed bottom portion 44. A fuel passage 45 is formed on the inner peripheral side of the main body 42.
Further, the main body 42 has a through hole 46 communicating with the fuel passage 45.
Are formed. The bottom portion 44 of the main body 42 is the truncated cone portion 4
41 and the conical portion 442, and the connecting portion between the truncated cone portion 441 and the conical portion 442 is the contact portion 41a.

The lid member 43 is installed at the end of the body 42 opposite to the bottom 44. The cover member 43 has a recess 421.
Is formed, and the end portion of the main body 42 opposite to the bottom portion 44 is installed in the recess 421 by press fitting or the like. The inner peripheral portion of the lid member 43 forms a fuel passage 45 together with the main body 42. Further, the lid member 43 is formed with a communication passage 47 communicating with the fuel passage 45. Bottom part 4 of lid member 43
A projecting portion 42a is formed at the end opposite to 4. The protrusion 42a corresponds to the pin member of the first embodiment. In the third embodiment, a part of the fuel passage 45 and the through hole 4
The nozzle needle 41 can be formed by connecting the main body 42 formed with 6 and the other part of the fuel passage 45 and the lid member 43 formed with the communication passage 47.

(Fourth Embodiment) FIG. 6 shows a fuel injection nozzle according to a fourth embodiment of the present invention. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. The fuel injection nozzle 10 of the fourth embodiment differs from that of the first embodiment in the shape of the communication passage 28 formed in the nozzle needle 21. As shown in FIG. 6, in the case of the fourth embodiment, the communication passage 28 is composed of a plurality of communication holes 281. The inner diameter of the communication hole 281 is set larger than the inner diameter of the communication hole 27. Further, the inner diameter of the communication hole 281 or the hole having the smaller inner diameter is set to be smaller than the inner diameter of the injection hole 12.

In the fourth embodiment, the communication passage 28 is constituted by a plurality of communication holes 281, so that among the foreign matters contained in the fuel supplied from the fuel supply passage 14, a relatively large foreign matter is caught in the communication hole 281. Gathered. Then, the fuel from which the relatively large foreign matter has been removed flows into the fuel passage 25 and the through hole 27
Is supplied to the injection hole 12 via the fuel flow path 19. In the through hole 27, fine foreign matter that is difficult to collect in the communication hole 281 is collected.

In the fourth embodiment, the foreign matter contained in the fuel can be removed by the communication hole 281 and the communication hole 27. Therefore, the through-hole 2 is caused by the relatively large foreign matter contained in the fuel.
7 is prevented from clogging. Therefore, the pressure loss of the fuel due to the clogging of the through holes 27 is reduced, and the foreign matter contained in the fuel can be collected and removed more reliably. Further, since either the communication hole 281 or the communication hole 27 has an inner diameter smaller than the inner diameter of the injection hole 12, clogging of the injection hole 12 can be prevented.

(Fifth Embodiment) FIG. 7 shows a fuel injection nozzle portion according to a fifth embodiment of the present invention. The fuel injection nozzle 50 of the fifth embodiment differs from that of the first embodiment in the shapes of the nozzle body 51 and the nozzle needle 61.

As shown in FIG. 7, the nozzle body 51 is
A guide hole 52 for accommodating the nozzle needle 61 and a fuel supply passage 53 are formed inside. Nozzle body 5
A nozzle hole 54 is formed at 1. The guide hole 52 is formed in the axial direction, and has a small diameter portion 55 in which a fuel reservoir 551 communicating with the fuel supply passage 53 is formed, and a large diameter portion 56. The inner wall of the nozzle body 51 forming the small diameter portion 55 is a sliding portion that slidably supports the nozzle needle 61. A truncated cone surface 57 is connected to the end of the guide hole 52 on the injection hole 54 side, and a substantially annular valve seat portion 51 a is formed on the truncated cone surface 57.

The nozzle needle 61 has a bottom portion 62, a tubular portion 63 and a pin member 64 which are integrally formed. The bottom portion 62 has a truncated cone portion 621 and a cone portion 622, and the connecting portion between the truncated cone portion 621 and the cone portion 622 serves as an annular contact portion 61a. A space surrounded by the inner peripheral surfaces of the bottom portion 62, the cylinder portion 63, and the pin member 64 is a fuel passage 65. The tubular portion 63 is formed in a substantially cylindrical shape and has a large diameter portion 631 and a small diameter portion 632. The outer diameter of the large diameter portion 631 is substantially the same as the inner diameter of the small diameter portion 55, and the outer peripheral surface of the large diameter portion 631 is slidable with the inner peripheral surface of the small diameter portion 55 of the nozzle body 51. The outer diameter of the small diameter portion 632 is smaller than the inner diameter of the large diameter portion 56, and a gap is formed between the small diameter portion 632 and the inner peripheral surface of the large diameter portion 56. This gap becomes the fuel flow path 58.

A communication passage 66 and a through hole 67 are formed in the cylindrical portion 63 to connect the inner peripheral surface and the outer peripheral surface. The communication passage 66 connects the fuel passage 65 and the fuel supply passage 53 via the fuel reservoir 551. On the other hand, the through hole 67 connects the fuel passage 65 and the fuel flow path 58. The inner diameter of the through hole 67 is smaller than the inner diameter of the communication passage 66 and smaller than the inner diameter of the injection hole 54.

In the fifth embodiment, the area of the sliding portion formed between the nozzle body 51 and the nozzle needle 61 is enlarged, so that the fuel supply passage 53 passes through the sliding portion to the fuel passage 58. The flowing fuel is reduced. As a result, most of the fuel supplied from the fuel supply passage 53 flows from the fuel passage 65 through the through hole 67 to the fuel passage 58, so that the foreign matter contained in the fuel can be collected and removed more reliably. . Further, since the area of the sliding portion is increased, it is easy to secure the coaxiality between the nozzle body 51 and the nozzle needle 61.

(Sixth Embodiment) A sixth embodiment of the present invention is shown in FIG.
Shown in. The sixth embodiment is a modification of the fifth embodiment, and the fifth embodiment
The same components as those in the embodiment are designated by the same reference numerals, and the description thereof will be omitted. As shown in FIG. 8, when the area of the sliding portion of the fuel injection nozzle 50 increases, the axial length of the fuel flow path 58 decreases. Therefore, it is necessary to reduce the area where the through holes can be formed and reduce the number of through holes. As a result, the pressure loss of the fuel flowing through the through hole is increased.

Therefore, in the sixth embodiment, the inner diameter of the through hole 68 is enlarged. On the other hand, if the inner diameter of the through hole 68 is increased, the ability of the through hole 68 to remove foreign matter contained in the fuel is reduced. Therefore, in the sixth embodiment, the inner diameter of the communication hole 691 forming the communication passage 69 is reduced. That is, in the sixth embodiment, the structures of the communication passage 69 and the through hole 68 are reversed from those of the above-described fourth embodiment. In the sixth embodiment, by making the inner diameter of the communication hole 691 forming the communication passage 69 smaller than the inner diameter of the injection hole 54, minute foreign matter contained in the fuel is communicated with the communication hole 6
It can be removed at 91. Further, since the inner diameter of the through hole 68 is enlarged, the pressure loss of fuel is reduced.

(Seventh Embodiment) A seventh embodiment of the present invention is shown in FIG.
Shown in. In the seventh embodiment, the structure of the fuel injection nozzle 70 is different from that of the first embodiment. As shown in FIG. 9, the nozzle body 71 has therein a guide hole 72 for accommodating the nozzle needle 81 and a fuel supply passage 73. A nozzle hole 74 is formed in the nozzle body 71. Guide hole 7
2 is formed in the axial direction, and has a fuel reservoir 75 communicating with the fuel supply passage 73, a small diameter portion 76, and a large diameter portion 77. The inner wall of the nozzle body 71 forming the small diameter portion 76 is a sliding portion that slidably supports the nozzle needle 81. A truncated cone surface 78 is connected to an end of the guide hole 72 on the injection hole 74 side, and the truncated cone surface 78 is connected to the valve seat portion 71a.
Are formed.

The nozzle needle 81 is formed in a solid rod shape. The nozzle needle 81 has a pin member 82, a large-diameter cylindrical portion 83, a small-diameter cylindrical portion 84, a truncated cone portion 85, and a cone portion 86, and a connecting portion between the truncated cone portion 85 and the cone portion 86 is an abutting portion. 81a. The outer diameter of the large-diameter cylindrical portion 83 is substantially the same as the inner diameter of the small-diameter portion 76, and the outer peripheral surface of the large-diameter cylindrical portion 83 is slidable with the inner peripheral surface of the small-diameter portion 76 of the nozzle body 71. The outer diameter of the small-diameter column portion 84 is smaller than the inner diameter of the large-diameter portion 77, and a gap is formed between the small-diameter column portion 84 and the inner peripheral surface of the large-diameter portion 77. This gap becomes the fuel flow path 79.

A filter member 90 is installed on the injection hole 74 side of the fuel reservoir 75 formed in the nozzle body 71, that is, on the fuel outlet side. A hole smaller than the inner diameter of the injection hole 74 is formed in the filter member 90, and foreign matter smaller than the inner diameter of the injection hole 74 contained in the fuel is removed at the inlet side of the injection hole 74. In the seventh embodiment, since the nozzle needle 81 does not need to be processed with holes such as the fuel passage and the through hole, the fuel injection nozzle 70 can be easily formed.

In the above-mentioned plural embodiments, the individual constitutions have been explained for each embodiment, but it is also possible to apply the plural embodiments in combination. Further, in the above-described embodiments, the example in which the fuel injection nozzle of the present invention is applied to the injector configuring the common rail fuel injection system of the diesel engine has been described. However, the fuel injection nozzle of the present invention is applicable not only to the common rail fuel injection system but also to other diesel engines such as a fuel injection nozzle opened and closed by the pressure of the fuel directly supplied from the fuel pump to the injector, Further, the fuel injection nozzle of the present invention can be applied not only to a diesel engine but also to an injector of a gasoline engine. Further, the opening / closing of the fuel injection nozzle is not limited to the one by electromagnetic drive. Further, in the above-described embodiments, the case where the communication passage and the through hole are formed at two locations in the circumferential direction of the nozzle needle has been described.
It may be one place or three or more places, and is not limited to two places.

Furthermore, although the present invention is applied to the fuel injection nozzle having a normal injection hole in the above-described embodiments, for example, the variable injection hole type in which the injection hole opened / closed differs depending on the lift amount of the nozzle needle. The present invention can be applied to such fuel injection nozzles.

[Brief description of drawings]

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

FIG. 2 is a schematic partial sectional view showing an injector to which the fuel injection nozzle according to the first embodiment of the present invention is applied.

3 is a schematic view showing the fuel injection nozzle shown in FIG. 1, and is a view showing a cross section of the nozzle body and an appearance in which the nozzle needle is rotated 90 ° in the circumferential direction from FIG.

FIG. 4 is a schematic sectional view showing a fuel injection nozzle according to a second embodiment of the present invention.

FIG. 5 is a schematic sectional view showing a fuel injection nozzle according to a third embodiment of the present invention.

FIG. 6 is a schematic sectional view showing a fuel injection nozzle according to a fourth embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a fuel injection nozzle according to a fifth embodiment of the present invention.

FIG. 8 is a schematic sectional view showing a fuel injection nozzle according to a sixth embodiment of the present invention.

FIG. 9 is a schematic view showing a fuel injection nozzle according to a seventh embodiment of the present invention, showing a cross section of a nozzle body and an appearance of a nozzle needle.

[Explanation of symbols]

10, 30, 40, 50, 70 Fuel injection nozzle 11, 51, 71 Nozzle body 11a, 51a, 71a Valve seat part 12, 54, 74 injection holes 14, 53, 73 Fuel supply path 19, 58, 79 Fuel flow path 21, 31, 41, 61, 81 Nozzle needle 21a, 31a, 41a, 61a, 81a Contact part 22, 34, 44, 62 bottom 23, 63 tube 24, 64, 82 pin members 25, 35, 45, 65 Fuel passage 26, 28, 36, 47, 66, 69 Communication passage 27, 37, 46, 67, 68 Through holes 32, 42 body 33 sheet member 43 Lid member 75 Fuel puddle 90 Filter member 281, 691 communication holes

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02M 61/16 F02M 61/16 KT 61/18 350 61/18 350C

Claims (10)

[Claims] 1. A nozzle body having a nozzle hole, a valve seat portion installed on the inlet side of the nozzle hole, and a fuel supply passage for supplying fuel to the nozzle hole, and a reciprocating member on the inner peripheral side of the nozzle body. Supported slidably,
Injection of fuel from the injection hole has an abutting portion that can be seated on the valve seat portion, and the abutting portion is seated on the valve seat portion or the abutting portion is separated from the valve seat portion. A fuel injection nozzle including a nozzle needle that connects and disconnects, a fuel flow path that communicates with the injection hole is formed between the nozzle needle and the nozzle body, and the nozzle needle has an internal axial direction. A fuel injection nozzle having a formed fuel passage, a communication passage that communicates the fuel passage with the fuel supply passage, and a through hole that communicates the fuel passage with the fuel passage. 2. The nozzle needle has a bottom portion and a tubular portion that are integrally formed, the abutment portion is formed on an outer peripheral portion of the bottom portion, and the communication passage and the through hole are provided in the tubular portion. The fuel injection nozzle according to claim 1, wherein the fuel injection nozzle is formed. 3. The fuel injection nozzle according to claim 2, wherein the nozzle needle has a pin member that seals an end portion of the fuel passage opposite to the bottom portion. 4. The nozzle needle has a tubular main body having a bottom portion, and a seat member formed separately from the main body and installed at an end portion of the main body opposite to the bottom portion. The fuel injection nozzle according to claim 1, wherein the communication passage and the through hole are formed in the main body, and the contact portion is formed in the sheet member. 5. The nozzle needle has a main body having a bottom portion, and a lid member formed separately from the main body and installed at an end portion of the main body opposite to the bottom portion, The fuel injection nozzle according to claim 1, wherein the main body is formed with the abutting portion on the through hole and the outer peripheral portion, and the lid member is formed with the communication passage. 6. The fuel injection nozzle according to claim 1, wherein an inner diameter of the through hole is smaller than an inner diameter of the communication passage. 7. The fuel injection nozzle according to claim 1, wherein an inner diameter of the through hole is larger than an inner diameter of the communication passage. 8. The fuel injection nozzle according to claim 1, wherein an inner diameter of one of the through hole and the communication passage is smaller than an inner diameter of the injection hole. 9. The nozzle needle has a guide portion slidable with the inner peripheral side of the nozzle body between the communication passage and the through hole. The fuel injection nozzle according to claim 1. 10. A nozzle body having a nozzle hole, a valve seat portion installed on the inlet side of the nozzle hole, and a fuel supply passage for supplying fuel to the nozzle hole, and a reciprocating member on the inner peripheral side of the nozzle body. Supported slidably,
A fuel passage communicating with the nozzle hole and a fuel reservoir communicating with the fuel supply passage and the fuel passage are formed between the nozzle body and the nozzle body, and a contact portion that can be seated on the valve seat portion is provided, A nozzle needle for intermittently injecting fuel from the injection hole by seating the contact portion on the valve seat portion or separating the contact portion from the valve seat portion; and on a fuel outlet side of the fuel pool. A fuel injection nozzle comprising: a filter member that is installed.