JP2016044619A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve for controlling under a high accuracy an amount of fuel injected from a plurality of injection holes.SOLUTION: In this invention, an inner needle 40 for opening or closing a central injection hole 26 is arranged to be reciprocatable in integral with an inner core 45. An outer core 55 for storing the inner core 45 in a reciprocatable manner is arranged to be reciprocatable in integral with an outer needle 50 for opening or closing an outer injection hole 27. A first spring 31 abutted against the outer core 55 biases the outer needle 50 toward a valve closing direction. A second spring 32 arranged between the outer core 55 and the inner core 45 biases the inner needle 40 toward the valve closing direction with a smaller biasing force than the biasing force of the first spring 31. Upon supplying electrical power to a coil 36, at first, the inner core 45 moves toward a valve opening direction to open the central injection hole 26. Further, as electrical power supplied to the coil 36 is increased, the outer core 55 moves in the valve opening direction to cause the outer injection hole 27 to be opened.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel injection valve for injecting and supplying fuel to an internal combustion engine (hereinafter referred to as “engine”).

  2. Description of the Related Art Conventionally, a fuel injection valve that injects fuel in a housing by individually controlling opening and closing of a plurality of injection holes in the housing by reciprocating movement of a plurality of needles is known. The fuel injection valve is configured so that the fuel injection amount can be changed in a wide range by properly using a plurality of injection holes in accordance with the operating state of the engine. For example, Patent Document 1 discloses an inner needle that opens and closes a central injection hole formed at one end in the central axis direction of a housing, and a radially outer side of the central injection hole that is provided on the radially outer side of the inner needle. A fuel injection valve including an outer needle that opens and closes an outer injection hole is described.

JP 2006-220129 A

  In the fuel injection valve described in Patent Document 1, the housing has a central nozzle hole valve seat in which the inner needle is separated or abutted when opening and closing the central nozzle hole, and an outer needle is separated or abutted when the outer nozzle hole is opened and closed. It has an outer nozzle hole seat. The central injection hole valve seat is formed in an annular shape with respect to the central axis of the fuel injection valve. On the other hand, the outer nozzle hole seat has the outer nozzle hole formed radially outside the central nozzle hole. For example, the outer nozzle hole is on a circumference centered on a point on the central axis of the fuel injection valve. When a plurality of fuel injection valves are formed, they are formed at two locations, that is, the radially inner side of the inner opening of the outer injection hole and the radially outer side of the inner opening of the outer injection hole as viewed from the central axis of the fuel injection valve. Further, for example, when a plurality of outer injection holes are formed on an arc included in a circumference centered on a point on the central axis of the fuel injection valve, the outer injection hole is shifted to a position shifted from the central axis of the fuel injection valve. It is formed so as to surround the outer nozzle hole.

  In the fuel injection valve described in Patent Document 1, the outer needle is arranged on the outer side so that fuel flowing toward the central injection hole is not injected from the outer injection hole when only a central injection hole is opened and a relatively small amount of fuel is injected. The radial inner part of the outer nozzle hole seat between the inner opening of the nozzle hole and the inner opening of the central nozzle hole and the radial outer part of the outer nozzle hole seat are respectively applied with the same surface pressure. It is urged to touch. However, if the surface pressure on the radially inner part of the outer nozzle hole seat differs from the surface pressure on the radially outer part of the outer nozzle valve seat due to changes over time, the liquid tightness between the central nozzle hole and the outer nozzle hole is maintained. You may not be able to do it. For this reason, in the fuel injection valve described in Patent Document 1, the amount of fuel injected from the central injection hole and the outer injection hole cannot be controlled with high accuracy.

  An object of the present invention is to provide a fuel injection valve that controls the amount of fuel injected from a plurality of injection holes with high accuracy.

The present invention is a fuel injection valve, and includes a housing, an inner needle, an inner core, an outer needle, an outer core, a fixed core, a coil, a first biasing member, and a second biasing member.
The inner needle is provided inside the housing so as to be able to reciprocate, and one end thereof is formed so as to be able to contact a first valve seat formed around the first injection hole.
The inner core is provided on the radially outer side of the other end of the inner needle so as to be able to reciprocate integrally with the inner needle.
The outer needle is provided on the radially outer side of the inner needle so as to be able to reciprocate inside the housing, and one end thereof is formed so as to be in contact with a second valve seat formed around the second injection hole. Yes.
The outer core is provided at the other end of the outer needle so as to be able to reciprocate integrally with the outer needle, and accommodates the inner core in a reciprocating manner inside.
The first biasing member biases the outer core so that one end portion of the outer needle comes into contact with the second valve seat.
The second urging member is an end surface of the inner needle opposite to the first valve seat, or an end surface of the inner core opposite to the first valve seat and an inner wall of the outer core, and is an outer wall on the first valve seat side. It is provided between the first end surface. The second biasing member biases the inner needle so that one end of the inner needle comes into contact with the first valve seat.
The fuel injection valve of the present invention is characterized in that the biasing force of the first biasing member is larger than the biasing force of the second biasing member.

  In the fuel injection valve of the present invention, the inner needle can be brought into contact with the first valve seat. The inner core accommodated in the outer core so as to be reciprocally movable is provided so as to be capable of reciprocating integrally with the inner needle, and the urging force of the second urging member that urges the inner needle to abut against the first valve seat, and the outer core And a magnetic attraction force that urges the inner core and the inner needle in the valve opening direction.

  In the fuel injection valve of the present invention, the outer needle is formed so as to be able to contact the second valve seat. The outer core is provided so as to be able to reciprocate integrally with the outer needle, and is generated between the urging force of the first urging member that urges the outer needle to abut against the second valve seat and the fixed core, and the outer core and the outer core. A magnetic attractive force that urges the needle in the valve opening direction acts.

  In the fuel injection valve of the present invention, the urging force of the first urging member is larger than the urging force of the second urging member. Thus, when electric power is supplied to the coil housed in the outer core, the inner needle that contacts the first valve seat is separated from the first valve seat by the biasing force of the second biasing member, and only the first nozzle hole is initially used. Can be opened. Thereafter, the outer needle that contacts the second valve seat by the biasing force of the first biasing member is separated from the second valve seat, and the second nozzle hole can be opened. Thus, in the fuel injection valve of the present invention, the opening and closing of the first injection hole and the second injection hole can be individually controlled by the magnitude of the electric power supplied to one coil. Therefore, the case where only the first nozzle hole is opened and the case where both the first nozzle hole and the second nozzle hole are opened are reliably controlled, and the amount of fuel injected from the plurality of nozzle holes is controlled with high accuracy. be able to.

It is sectional drawing of the fuel injection valve by one Embodiment of this invention. It is the II section enlarged view of FIG. It is the III section enlarged view of FIG. It is IV arrow line view of FIG. It is sectional drawing explaining the effect | action of the fuel injection valve by one Embodiment of this invention, Comprising: It is sectional drawing explaining the effect | action different from FIG. It is sectional drawing explaining the effect | action of the fuel injection valve by one Embodiment of this invention, Comprising: It is sectional drawing explaining the effect | action different from FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(One embodiment)
A fuel injection valve 1 according to an embodiment of the present invention is shown in FIGS. 1, 2, 4 to 6 illustrate a valve opening direction in which the inner needle 40 is separated from the injection nozzle 25 and a valve closing direction in which the inner needle 40 is in contact with the injection nozzle 25. To do.

  The fuel injection valve 1 is used, for example, in a fuel injection device of a direct injection gasoline engine (not shown), and injects and supplies gasoline as fuel to the engine at a high pressure. The fuel injection valve 1 includes a housing 20, an inner needle 40, an inner core 45, an outer needle 50, an outer core 55, a fixed core 30, a coil portion 35, a first spring 31 as a “first urging member”, and a “second urging force”. A second spring 32 as a “member”, a third spring 33 as a “third urging member”, and the like are provided.

  As shown in FIG. 1, the housing 20 includes a cylindrical member 21 and an injection nozzle 25 as “one end portion in the central axis direction”.

  The cylindrical member 21 is formed of, for example, a magnetic material such as ferritic stainless steel and subjected to a magnetic stabilization process. The cylindrical member 21 accommodates an inner needle 40, an inner core 45, an outer needle 50, an outer core 55, and the like, which will be described later, in a reciprocating manner.

  The injection nozzle 25 is provided at one end of the cylindrical member 21. The injection nozzle 25 is formed in a bottomed cylindrical shape from a metal such as martensitic stainless steel, and is welded to the cylindrical member 21. The injection nozzle 25 is subjected to a quenching process so as to have a predetermined hardness. The injection nozzle 25 is formed of an injection part 251 and a cylinder part 252.

  The injection part 251 is formed in line symmetry with the central axis CA0 of the housing 20 coaxial with the central axis of the fuel injection valve 1 as an axis of symmetry. The outer wall 253 of the injection unit 251 is formed so as to protrude from the inner side of the injection nozzle 25 in the direction of the central axis CA0. The injection unit 251 has a plurality of injection holes that communicate the inside and the outside of the housing 20.

  In the fuel injection valve 1 according to the embodiment, as shown in FIG. 3, one of the plurality of nozzle holes is formed on the central axis CA0. The nozzle hole formed on the central axis CA0 is referred to as a central nozzle hole 26 as a “first nozzle hole”. In addition, a plurality of nozzle holes formed on a part of an arc of a circumference C0 centering on a point on the center axis CA0 and being radially outside the center nozzle hole 26 are referred to as “second nozzle holes”. The outer nozzle hole 27 is used. In one embodiment, the outer injection holes 27 are formed on the arc so as to be arranged at equal intervals. However, the positions of the outer injection holes 27 may not be on a part of the arc of the circumference C0. As long as it is formed on the outside in the radial direction.

  The cylinder part 252 is provided so as to surround the radially outer side of the injection part 251 and extend in a direction opposite to the direction in which the outer wall 253 of the injection part 251 protrudes. The cylindrical part 252 has one end connected to the injection part 251 and the other end connected to the cylindrical member 21.

  The inner needle 40 is made of a metal such as martensitic stainless steel. The inner needle 40 is quenched so as to have a hardness substantially equal to the hardness of the injection nozzle 25.

  The inner needle 40 is accommodated in the housing 20 so as to be reciprocally movable. The inner needle 40 is formed of an inner main body portion 41, an inner seal portion 42 as "one end portion of the inner needle", an inner collar portion 43, and the like. In one embodiment, the inner body part 41, the inner seal part 42, and the inner collar part 43 are integrally formed.

The inner main body portion 41 is a rod-shaped portion in which an end portion on the fixed core 30 side is formed in a hollow shape. The inner main body 41 has an end on the fixed core 30 side inserted through an inner core 45 described later. A flow path 400 through which fuel flows toward the injection nozzle 25 is formed on the inner side of the end of the inner main body 41 on the fixed core 30 side. The flow path 400 communicates with a hole 411 formed so as to penetrate in the radial direction on the injection nozzle 25 side of the flow path 400. That is, the hole 411 communicates the flow path 400 and the outside of the inner main body 41.
An end of the inner main body 41 on the injection nozzle 25 side is inserted into an inner needle insertion hole 501 as an “inner needle insertion hole” formed inside the outer needle 50. The radially outer outer wall 412 of the end of the inner main body 41 on the injection nozzle 25 side is slidably provided on the inner wall 504 of the outer needle 50. Thereby, the reciprocating movement of the inner needle 40 is guided.

  The inner seal portion 42 is a rod-shaped portion provided at an end portion of the inner main body portion 41 on the injection nozzle 25 side. The outer diameter of the inner seal portion 42 is smaller than the outer diameter of the inner main body portion 41. An outer wall 421 at an end of the inner seal portion 42 opposite to the inner main body portion 41 can contact an inner wall 254 of an edge that forms an opening inside the central injection hole 26 that is an inner wall of the injection portion 251. Is formed. When the outer wall 421 and the inner wall 254 corresponding to the “first valve seat” of the central injection hole 26 are separated or contacted, the inner needle insertion hole 501 and the central injection hole 26 are blocked or communicated. That is, the central nozzle hole 26 opens and closes.

  The inner collar portion 43 is a substantially annular portion provided on the radially outer side of the end portion of the inner main body portion 41 on the fixed core 30 side with respect to the inner core 45. The outer diameter of the inner collar portion 43 is larger than the outer diameter of the inner main body portion 41. A flange nozzle side end surface 431 of the inner flange 43 on the injection nozzle 25 side is in contact with the inner core 45.

  The inner core 45 is a cylindrical member provided on the end of the inner main body 41 opposite to the fixed core 30 and on the radially outer side of the inner flange 43. The inner core 45 is made of a magnetic material and subjected to a magnetic stabilization process. On the fixed core 30 side of the inner core 45, an inner as an “end surface of the inner core opposite to the first valve seat” that can abut on an outer side first abutment surface 584 on the injection nozzle 25 side of the outer core 55 described later. A side contact surface 451 is provided.

  The inner core 45 has an accommodating space forming portion 453 that forms an accommodating space 452 that accommodates the inner collar portion 43 on the fixed core 30 side. The inner core 45 has an inner needle insertion hole 454 through which the inner main body 41 is inserted in the central axis direction. The inner needle insertion hole 454 communicates with the accommodation space 452. Since the inner needle insertion hole 454 has an inner diameter smaller than the inner diameter of the accommodation space 452, a step surface 455 is formed at a location where the inner needle insertion hole 454 and the accommodation space 452 communicate with each other. A flange nozzle side end surface 431 of the inner flange 43 on the injection nozzle 25 side is in contact with the step surface 455. As a result, the inner needle 40 and the inner core 45 reciprocate relative to the housing 20 together.

  The outer needle 50 is a reciprocating cylindrical member provided on the radially outer side of the inner main body 41. An end of the outer needle 50 on the fixed core 30 side is slidably provided on the inner wall of the cylindrical member 21. The end of the outer needle 50 on the injection nozzle 25 side is inserted inside the injection nozzle 25. The outer wall at the end of the outer needle 50 opposite to the fixed core 30 is formed to be slidable with the inner wall of the cylindrical portion 252. Thereby, the outer needle 50 is guided to reciprocate by the inner wall of the housing 20.

Inside the outer needle 50, an inner needle insertion hole 501 is formed in the direction of the central axis CA0. The outer wall 502 of the end of the outer needle 50 on the side of the injection nozzle 25 is formed so as to be able to come into contact with the inner wall 255 of the edge that forms the opening inside the outer injection hole 27 that is the inner wall of the injection unit 251. . When the outer wall 502 and the inner wall 255 corresponding to the “second valve seat” of the outer injection hole 27 are separated or contacted, the inner side of the cylindrical member 21 and the outer injection hole 27 are blocked or communicated. That is, the outer nozzle hole 27 opens and closes.
A communication hole 503 that connects the inner needle insertion hole 501 and the outer side of the outer needle 50 is formed at the end of the outer needle 50 on the fixed core 30 side. The fuel flowing toward the outer injection hole 27 flows through the communication hole 503.

  The outer core 55 is a cylindrical member provided on the fixed core 30 side of the outer needle 50. In one embodiment, the outer core 55 is formed integrally with the outer needle 50. The outer diameter of the outer core 55 is larger than the outer diameter of the outer needle 50. The outer core 55 is formed of an outer core casing 56, an outer core main body 58, and the like.

  The outer core casing 56 is a cylindrical member formed so as to extend in the valve opening direction from the radially outer side of the end portion of the outer needle 50 on the fixed core 30 side. The outer core casing 56 is made of a magnetic material and subjected to a magnetic stabilization process. A radially outer wall 561 on the radially outer side of the outer core casing 56 is slidably formed on the inner wall of the cylindrical member 21. Inside the outer core casing 56, a coil 36, a nonmagnetic member 37, and an outer core main body 58 are provided in the order from the radially outer direction to the radially inner direction.

  The outer core main body 58 is a cylindrical portion provided between the inner core 45 and the fixed core 30. The outer core main body 58 has a through hole that penetrates the outer core main body 58 in the direction of the central axis CA0. The through hole includes a small diameter through hole 581 formed on the fixed core 30 side and a large diameter through hole 582 formed on the inner core 45 side. The other end of the second spring 32 is in contact with the inner wall of the outer core main body 58 forming the small diameter through hole 581 and the inner wall of the outer core main body 58 forming the large diameter through hole 582. A step surface 583 as an “end surface” is formed.

  An outer side first contact surface 584 that can contact the inner side contact surface 451 is formed on the injection nozzle 25 side of the outer core main body 58. When the outer wall 421 and the inner wall 254 are in contact with each other and the outer wall 502 and the inner wall 255 are in contact with each other, the inner side contact surface 451 and the outer side first contact surface 584 are, as shown in FIG. The distance Hf is maintained while being maintained.

  On the fixed core 30 side of the outer core main body 58, an outer second contact surface 585 that can contact the fixed core side contact surface 301 formed on the injection nozzle 25 side of the fixed core 30 is formed. When the outer wall 421 and the inner wall 254 are in contact with each other, and when the outer wall 502 and the inner wall 255 are in contact with each other, the fixed core side contact surface 301 and the outer side second contact surface 585 are as shown in FIG. , With the distance Hs maintained.

  The coil portion 35 is formed in a substantially cylindrical shape, and is provided between the outer core casing 56 and the outer core body portion 58 and in the vicinity of the inner core 45. As used herein, “near” refers to a position where the inner wall 351 on the radially inner side of the coil part 35 and the outer wall 456 on the radially outer side of the inner core 45 slide, as shown in FIG. The positional relationship between the inner wall 351 and the outer wall 456 of the inner core 45 is not limited to this.

  The coil unit 35 includes a coil 36 that forms a magnetic field in the surroundings when electric power is supplied, and a nonmagnetic member 37 formed of a nonmagnetic material. When a magnetic field is formed by the coil 36, a magnetic circuit is formed in the fixed core 30, the outer core main body 58, the inner core 45, the outer core casing 56, the cylindrical member 21, and the holder 15.

  The fixed core 30 is welded to the nonmagnetic member 22 provided on the inner wall of the cylindrical member 21 and is fixed to the inside of the housing 20. The fixed core 30 is made of a magnetic material, and has a surface plated with, for example, chrome so as to secure a necessary hardness to withstand contact with the outer core 55. The fixed core 30 is subjected to a magnetic stabilization process and is provided in a magnetic field formed by the coil 36.

  One end of the first spring 31 is provided so as to contact the outer second contact surface 585 of the outer core main body 58 on the fixed core 30 side. The other end of the first spring 31 is in contact with the end surface 111 on the injection nozzle 25 side of the adjusting pipe 11 that is press-fitted and fixed inside the fixed core 30. The first spring 31 urges the outer core body 58 in the direction of the injection nozzle 25, that is, the valve closing direction.

  The second spring 32 is provided between the inner needle 40 and the inner core 45 and the outer core 55. One end of the second spring 32 is in contact with the flange fixed core side end surface 432 of the inner flange 43 on the fixed core 30 side. Further, one end of the second spring 32 may abut on an end surface 413 as “an end surface opposite to the first valve seat of the needle member” on the side opposite to the injection nozzle 25 of the inner main body 41. The second spring 32 urges the inner needle 40 and the outer core main body portion 58 so that the inner needle 40 and the inner core 45 and the outer core main body portion 58 are separated from each other. The other end of the second spring 32 may abut on an inner abutment surface 451 as “an end surface of the inner core opposite to the first valve seat”.

  The third spring 33 is provided between the outer core casing 56 and the housing 20 on the injection nozzle 25 side of the outer core casing 56. One end of the third spring 33 is in contact with an outer surface of the outer core casing 56 and an end surface 562 as an “outer second end surface” formed on the injection nozzle 25 side. Further, the other end of the third spring 33 is in contact with an inner wall 211 as an “inner wall of the housing” of the cylindrical member 21 facing the end surface 562. The third spring 33 biases the outer core casing 56 in the direction of the fixed core 30, that is, in the valve opening direction.

  In one embodiment, the urging force Fsp1 of the first spring 31 is set to be larger than the urging force Fsp2 of the second spring 32. Thereby, when electric power is not supplied to the coil 36, a force having a magnitude of (Fsp 1 -Fsp 2) acts on the outer core main body 58 in the valve closing direction, and the outer wall 502 of the outer needle 50 is connected to the injection portion 251. It will be in the state contact | abutted to the inner wall 255. FIG.

  A cylindrical fuel introduction pipe 12 is provided on the side of the fixed core 30 opposite to the injection nozzle 25. A filter 13 is provided inside the fuel introduction pipe 12. The filter 13 collects foreign matters contained in the fuel that has flowed from the introduction port 14 of the fuel introduction pipe 12.

  A holder 15 that covers the radially outer side of the fuel introduction pipe 12 is formed at the end of the cylindrical member 21 opposite to the injection nozzle 25 side. The holder 15 has a connector 16 formed to extend outward in the radial direction. The connector 16 is insert-molded with a terminal 17 for supplying electric power to the coil 36.

  The fuel flowing into the inside of the housing 20 from the introduction port 14 of the fuel introduction pipe 12 passes through the inside of the adjusting pipe 11, the inside of the fixed core 30, the small diameter through hole 581, the large diameter through hole 582, the flow path 400, and the hole 411. It is guided to the inner needle insertion hole 501 through the inner needle. A part of the fuel guided to the inner needle insertion hole 501 is guided between the outer wall 412 of the inner main body 41 and the inner wall 504 of the outer needle 50. Further, the fuel in the inner needle insertion hole 501 excluding the fuel guided to the vicinity of the central injection hole 26 of the injection nozzle 25 passes through the communication hole 503 and the outer wall 505 formed on the outer side in the radial direction of the outer needle 50 and the cylindrical member 21. Between the inner wall 212 and the inner wall 212 formed radially inward.

Next, the operation of the fuel injection valve 1 will be described.
When power is not supplied to the coil 36, the inner needle 40 and the inner core 45 are attached to the fuel pressure between the outer wall 412 of the inner body portion 41 and the inner wall 504 of the outer needle 50 and the second spring 32. The force Fsp2 acts in the valve closing direction. Specifically, as shown in FIG. 2, the seat diameter of the outer wall 421 of the inner seal portion 42 and the inner wall 254 of the injection nozzle 25 is the seat diameter S26, and the pressure of the fuel introduced from the inlet 14 is the pressure Pf0. Then, the force in the valve closing direction calculated by the equation (1) acts on the inner needle 40 and the inner core 45.
Fsp2 + Pf0 × {π / 4 × (S26) ² } (1)
In the fuel injection valve 1, when no power is supplied to the coil 36, the outer wall 421 and the inner wall 254 are in contact with each other by the force in the valve closing direction calculated by the equation (1), and the central injection hole 26 is closed. .

Further, the pressure of fuel between the outer wall 505 of the outer needle 50 and the inner wall 212 of the cylindrical member 21 and the urging force Fsp1 of the first spring 31 act on the outer needle 50 and the outer core 55 in the valve closing direction. On the other hand, the biasing force Fsp3 of the third spring 33 acts in the valve opening direction. Specifically, as shown in FIG. 2, when the seat diameter of the outer wall 502 of the outer needle 50 and the inner wall 255 of the injection nozzle 25 is a seat diameter S27, the outer needle 50 and the outer core 55 are calculated by the equation (2). The force in the valve closing direction is applied.
(Fsp1-Fsp3) + Pf0 × {π / 4 × (S27) ² } (2)
In the fuel injection valve 1, when no power is supplied to the coil 36, the outer wall 502 and the inner wall 255 are in contact with each other by the force in the valve closing direction calculated by Expression (2), and the outer injection hole 27 is closed. .

  In the fuel injection valve 1, when electric power is not supplied to the coil 36, the positional relationship among the inner needle 40, the inner core 45, the outer needle 50, and the outer core 55 is as shown in FIG. Specifically, a gap 450 having a distance Hf in the central axis CA0 direction is formed between the inner contact surface 451 and the outer first contact surface 584. A gap 530 having a distance Hs in the direction of the central axis CA is formed between the fixed core side contact surface 301 and the outer side second contact surface 585.

  When electric power is supplied to the coil 36, a magnetic field is formed around the coil 36. When a magnetic field is formed around the coil 36, a magnetic circuit (two-dot chain arrow MC51 in FIG. 5) passing through the fixed core 30, the outer core body 58, the inner core 45, the outer core casing 56, the cylindrical member 21, and the holder 15; And the magnetic circuit (two-dot chain arrow MC52 of FIG. 5) which passes along the fixed core 30, the outer core main-body part 58, the inner core 45, and the outer core casing 56 is formed. When these magnetic circuits are formed, a magnetic attractive force Fmg <b> 1 is generated between the fixed core 30 and the outer core main body 58 and between the outer core main body 58 and the inner core 45. When the magnetic attractive force Fmg1 becomes larger than the value of the expression (1), as shown in FIG. 5, the inner needle 40 and the inner core 45 move in the valve opening direction, and the outer wall 421 of the inner seal portion 42 is the inner wall 254 of the injection nozzle 25. Separate from. When the outer wall 421 is separated from the inner wall 254, fuel between the outer wall 412 of the inner main body 41 and the inner wall 504 of the outer needle 50 is injected outside through the central injection hole 26.

  When the magnetic attractive force Fmg1 is larger than the value of the formula (1), the two magnetic circuits (two-dot chain arrows MC51 and MC52 in FIG. 5) described above can also be interposed between the fixed core 30 and the outer core main body 58. Magnetic attraction force Fmg2 is generated. However, in one embodiment, since the magnetic attractive force Fmg2 is smaller than the value of the equation (2) when the magnetic attractive force Fmg1 is larger than the value of the equation (1), the outer core main body 58 does not move in the valve opening direction. The gap of the distance Hs is still formed. For this reason, the outer nozzle hole 27 remains closed.

When power is further supplied to the coil 36 after the central injection hole 26 is opened, the inner core 45 moving in the valve opening direction comes into contact with the outer core main body 58.
Furthermore, when the power supply to the coil 36 is relatively long, the magnetic circuit (two-dot chain arrow in FIG. 6) passing through the fixed core 30, the outer core 55, the inner core 45, the outer core casing 56, the cylindrical member 21, and the holder 15. MC 61), and magnetic attraction generated between the fixed core 30 and the outer core main body 58 by a magnetic circuit (two-dot chain arrow MC62 in FIG. 6) passing through the fixed core 30, the outer core 55, the inner core 45, and the outer core casing 56. The force Fmg2 becomes larger than the value of the formula (2). When the magnetic attractive force Fmg2 becomes larger than the value of the expression (2), the outer needle 50 and the outer core 55 move in the valve opening direction as shown in FIG. 6, and the outer wall 502 of the outer needle 50 is moved from the inner wall 255 of the injection nozzle 25. Separate. When the outer wall 502 is separated from the inner wall 255, fuel between the outer wall 505 of the outer needle 50 and the inner wall 212 of the cylindrical member 21 is injected outside through the outer injection hole 27.

  After the outer injection hole 27 is opened, the outer core 55 that moves in the valve opening direction contacts the fixed core 30. Thereby, the maximum lift amount of the inner needle 40 is the distance (Hf + Hs). Further, the maximum lift amount of the outer needle 50 is the distance Hs.

When the supply of power to the coil 36 is stopped, the magnetic attractive force acting on the inner core 45 and the outer core 55 gradually decreases. When the magnetic attractive force Fmg1 generated between the outer core main body 58 and the inner core 45 becomes smaller than the biasing force Fsp2 of the second spring 32, the inner needle 40 moves in the valve closing direction. When the inner needle 40 moves in the valve closing direction, the outer wall 421 of the inner seal portion 42 and the inner wall 254 of the injection nozzle 25 come into contact with each other. Thereby, the central injection hole 26 is closed.
When the magnetic attractive force Fmg2 generated between the fixed core 30 and the outer core main body 58 is smaller than the difference between the biasing force Fsp1 of the first spring 31 and the biasing force Fsp3 of the third spring 33, the outer needle 50 is closed. Move in the valve direction. When the outer needle 50 moves in the valve closing direction, the outer wall 502 of the outer needle 50 and the inner wall 255 of the injection nozzle 25 come into contact with each other. Thereby, the outer injection hole 27 is closed.

In the fuel injection valve 1 according to the embodiment, the central injection hole 26 opens and closes when the outer wall 421 of the inner needle 40 is separated or brought into contact with the inner wall 254 corresponding to the valve seat of the central injection hole 26. Further, when the outer wall 502 of the outer needle 50 is separated or brought into contact with the inner wall 255 corresponding to the valve seat of the outer nozzle hole 27, the outer nozzle hole 27 opens and closes.
In the fuel injection valve 1, the outer core 55 that accommodates the inner core 45 so as to be reciprocally movable accommodates a coil portion 35 that forms a magnetic field. Thereby, when the coil part 35 forms a magnetic field around it, a magnetic attractive force is generated between the fixed core 30 and the outer core 55 and between the outer core 55 and the inner core 45. Thereby, the inner needle 40 and the outer needle 50 can be driven by the single coil part 35.

  In the fuel injection valve 1, the biasing force Fsp1 of the first spring 31 that biases the outer needle 50 in the valve closing direction is larger than the biasing force Fsp2 of the second spring 32 that biases the inner needle 40 in the valve closing direction. . Thus, when a magnetic attractive force is generated between the fixed core 30 and the outer core 55 and between the outer core 55 and the inner core 45, the inner needle 40 is first separated from the injection nozzle 25 and opens the central injection hole 26. Then, when the electric power supplied to the coil part 35 becomes large, the outer needle 50 can be separated from the injection nozzle 25 and the outer injection hole 27 can be opened.

  As described above, in the fuel injection valve 1 according to the embodiment, the inner needle 40 and the outer needle 50 are individually and reliably driven with respect to two different types of nozzle holes depending on the magnitude of electric power supplied to one coil portion 35. Can be controlled. Thereby, the fuel injection valve 1 can control the amount of fuel injected from the central injection hole 26 and the outer injection hole 27 with high accuracy, and can inject a relatively wide range of fuel injection amounts.

  In the fuel injection valve 1, when the valve is closed, the outer needle 50 and the outer core 55 are opened in the valve opening direction by the biasing force Fsp3 of the third spring 33 that gradually increases the biasing force against the outer core 55 moving in the valve closing direction. The outer needle 50 comes into contact with the injection nozzle 25 while being urged by the pressure. This prevents the outer needle 50 from coming into contact with the injection nozzle 25 vigorously when the valve is closed. Therefore, the outer wall 502 of the outer needle 50 can be prevented from being unexpectedly separated from the inner wall 255 of the injection nozzle 25, and the unexpected fuel injection from the outer injection hole 27 can be prevented.

  In the fuel injection valve 1, the coil portion 35 is provided in the vicinity of the inner core 45. As a result, the magnetic field formed by the coil 36 becomes relatively strong inside the inner core 45, and the magnetic attractive force Fmg1 generated between the inner core 45 and the outer core 55 becomes relatively large. Therefore, the fuel injection valve 1 can be driven with relatively little energy as compared with the case where the coil is provided on the outer side in the radial direction of the outer core casing or inside the housing.

  Further, the outer needle 50 has a communication hole 503 that allows the fuel to flow between the inner side and the outer side of the outer needle 50. Thereby, a sufficient amount of fuel injected from the outer nozzle hole 27 can be guided in the vicinity of the opening inside the outer nozzle hole 27.

(Other embodiments)
(A) In the above-described embodiment, the third needle is provided to prevent the outer needle from being unexpectedly separated from the injection nozzle by the movement of the outer needle in the valve closing direction. However, the third spring may not be provided.

  (A) In the above-described embodiment, the coil is provided in the vicinity of the inner core. However, the position where the coil is provided is not limited to this. A fixed core, an outer core, and an inner core are provided in the magnetic field formed by the coil, and the inner needle and the outer needle can be separated from the injection nozzle between the fixed core and the outer core and between the outer core and the inner core by the formed magnetic circuit. It is sufficient if a strong magnetic attractive force is generated.

  (C) In the above-described embodiment, the outer needle has the inner needle insertion hole and the communication hole through which the fuel injected from the outer injection hole flows. However, the outer needle may not have a communication hole.

  As mentioned above, this invention is not limited to such embodiment, It can implement with a various form in the range which does not deviate from the summary.

1 ... Fuel injection valve,
20 ・ ・ ・ Housing,
30 ... fixed core,
31 ... 1st spring (1st biasing member),
32 ・ ・ ・ Second spring (second urging member),
36 ・ ・ ・ Coil,
40 ・ ・ ・ Inner needle,
45 ・ ・ ・ Inner core,
50 ・ ・ ・ Outer needle,
55: Outer core.

Claims (4)

A first injection hole (26) that is formed at one end (25) in the direction of the central axis (CA0) and injects fuel, and a second injection that is formed radially outside the first injection hole and injects fuel. A housing (20) having a hole (27);
An inner needle (40) provided inside the housing so as to be reciprocally movable and having one end (42) capable of contacting a first valve seat (254) formed around the first nozzle hole;
An inner core (45) formed of a magnetic material and provided radially outside the other end of the inner needle so as to be reciprocally movable integrally with the inner needle;
An outer which is provided on the radially outer side of the inner needle so as to be able to reciprocate inside the housing and whose one end is in contact with a second valve seat (255) formed around the second nozzle hole. A needle (50);
An outer core (55) formed of a magnetic material, provided at the other end of the outer needle so as to be reciprocally movable integrally with the outer needle, and accommodating the inner core in a reciprocable manner inside;
A fixed core (30) provided on the opposite side of the outer core from the first valve seat;
A coil (36) which is provided inside the outer core and forms a magnetic field passing through the inner core, the outer core and the fixed core when power is supplied;
A first biasing member (31) for biasing the outer core so that one end of the outer needle comes into contact with the second valve seat;
An end face (413, 432) opposite to the first valve seat of the inner needle or an end face (451) opposite to the first valve seat of the inner core and an inner wall of the outer core, A second urging force provided between the outer first end surface (583) on the first valve seat side and urging the inner needle so that one end portion of the inner needle abuts on the first valve seat. A member (32);
With
The fuel injection valve (1), wherein a biasing force (Fsp1) of the first biasing member is larger than a biasing force (Fsp2) of the second biasing member.   An outer wall of the outer core, which is provided between an outer second end surface (562) of the outer core on the first valve seat side and an inner wall (211) of the housing, and one end portion of the outer needle is disposed on the first core. The fuel injection valve according to claim 1, further comprising a third urging member (33) for urging in a direction away from the two valve seats.   The fuel injection valve according to claim 1, wherein the coil is provided in the vicinity of the inner core.   The said outer needle has the communicating hole (503) which connects the inner needle insertion hole (501) in which the said inner needle is penetrated, and the outer side of the said outer needle, The any one of Claim 1 to 3 characterized by the above-mentioned. The fuel injection valve according to one item.

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