JP2010216432A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve achieving both suppression of narrowing the flow passage cross-sectional area of a fuel passage leading fuel to nozzle ports and suppression of generation of deposit. <P>SOLUTION: This fuel injection valve 10 includes: an inner wall surface 22 forming the fuel passage 26 and reduced in diameter toward a fuel downstream side; a valve seat 23 formed on the inner wall surface 22; a valve body 21 having a plurality of nozzle ports 25 injecting fuel led to flow out from a side downstream of the valve seat 23; and a needle 30 stopping and allowing fuel injection from the nozzle ports 25 by being seated on and separated from the valve seat 23. In the valve body 21, the valve seat 23 is formed with the plurality of nozzle ports 25, and a recessed portions 70 surrounding an inlet 25b is formed on the periphery of the inlet 25b of each nozzle port 25. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a fuel injection valve.

  A valve body having a fuel passage and an inner wall surface that is reduced in diameter toward the downstream side of the fuel, a valve seat that is formed on the inner wall surface, and a plurality of injection holes for injecting fuel that flows from the downstream side of the valve seat Is known (see Patent Document 1). In this type of fuel injection valve, a common sac chamber is provided on the inlet side of the plurality of injection holes.

  In the apparatus disclosed in Patent Document 1 as a kind of such fuel injection valve, a plurality of nozzle holes are provided in the valve seat, and an annular groove is provided as a “common sack chamber” at the inlets of the nozzle holes. ing. In this technique, even when the lift amount of the needle is small, the flow passage cross-sectional area flowing into the annular groove is sufficiently secured, so that it is possible to suppress a decrease in the flow rate of the fuel flowing into the nozzle hole inlet. In other words, the flow path cross-sectional area of the fuel passage that guides the fuel to the nozzle hole is not restricted by the “common sac chamber”.

JP 2001-12334 A

  However, in the prior art disclosed in Patent Document 1, since each nozzle hole is always in communication with the “common sac chamber” even after the fuel injection valve is closed, the combustion gas that has flowed into the sac due to a breathing action is detected. There is a risk that the fuel will chemically react due to the temperature rise due to combustion, resulting in the formation of deposits.

  In contrast to the above-described prior art, a method is conceivable in which an annular groove which is a “common suck chamber” is not provided. When the needle is seated on the valve seat, the nozzle hole is covered with the needle so that the respiratory action can be suppressed. However, in this method, the flow passage cross-sectional area is reduced during the small lift of the needle, resulting in a decrease in the flow rate of fuel flowing to the nozzle hole inlet.

  The present invention has been made in view of such circumstances, and its purpose is to suppress the reduction of the flow passage cross-sectional area of the fuel passage leading the fuel to the nozzle hole and to suppress the generation of deposits. An object of the present invention is to provide a fuel injection valve that is compatible.

  In order to achieve the above object, the present invention comprises the following technical means.

That is, according to the first aspect of the present invention, an inner wall surface that forms a fuel passage and is reduced in diameter toward the downstream side of the fuel, a valve seat that is formed on the inner wall surface, and a fuel that flows out from the downstream side of the valve seat. A fuel injection valve comprising: a valve body having a plurality of injection holes for injecting fuel; and a needle for stopping and allowing fuel injection from the injection holes by being seated and separated from the valve seat.
The valve body is characterized in that a plurality of injection holes are formed in the valve seat, and a recess surrounding the inlet is provided around the inlet of the injection hole.

  According to this, since the plurality of injection holes are formed in the valve seat, when the needle is seated on the valve seat, the plurality of injection holes can be closed with the needle. Further, since a recess surrounding the inlet is provided around the inlet of the nozzle hole, a recess as a “suck chamber” formed on the inlet side of the nozzle is formed for each nozzle hole. Therefore, when the needle is seated on the valve seat, the space between the inlet portions of the plurality of nozzle holes can be substantially closed. Therefore, the respiratory action is suppressed, and hence the generation of deposits can be suppressed.

  Also, when the needle is separated from the valve seat, the flow passage cross-sectional area of the fuel passage that guides fuel to the nozzle hole can be enlarged by the recess, so that the flow passage cross-sectional area can be reduced even if the needle is a small lift. Absent.

  According to the first aspect of the present invention, it is possible to achieve both suppression of restricting the flow passage cross-sectional area of the fuel passage that guides fuel to the nozzle hole and suppression of deposit generation.

  The invention according to claim 2 is characterized in that the inlet portion of the injection hole is displaced in the diameter reducing direction of the valve seat with respect to the recess.

  According to this, since the concave portion is shifted in the counter-reducing diameter direction of the valve seat with respect to the inlet portion of the injection hole, it is easy to enlarge the flow path cross-sectional area on the upstream side among the peripheral sides of the concave portion. Therefore, the structure which suppresses that the flow-path cross-sectional area of the fuel channel which guides a fuel to a nozzle hole is restrict | squeezed can be done easily.

  In the inventions according to claims 3 to 4, the concave portion is arranged in an annular shape over a position where the injection hole is located.

  According to this, the structure which suppresses that the flow-path cross-sectional area of the fuel passage which guide | induces a fuel to a nozzle hole is restrict | squeezed can be implement | achieved reliably.

  In the invention according to claim 4, among the peripheral sides of the recess, the upstream side is formed in an arc shape with a predetermined interval with respect to the outer diameter of the seat portion of the needle seated on and away from the valve seat. It is preferable.

  According to this, since the upstream side of the concave portion is formed in an arc shape having a predetermined interval with respect to the outer diameter of the needle seat portion, it is possible to effectively realize the enlargement of the cross-sectional area of the flow path.

It is sectional drawing which shows the fuel injection valve by 1st Embodiment of this invention, Comprising: It is the II sectional view taken on the line in FIG. It is sectional drawing which shows the structure of the front-end | tip part of the fuel injection valve in FIG. It is the top view seen from the arrow II direction of FIG. It is a figure which shows the front-end | tip part of FIG. 2, Comprising: It is sectional drawing corresponding to the time of valve opening of a fuel injection valve. It is a figure which shows the fuel injection valve concerning 2nd Embodiment, Comprising: It is a top view corresponding to FIG.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol to the component corresponding in each embodiment.

(First embodiment)
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. 1 to 3 show a fuel injection valve 10 according to the present embodiment. 2 and 3 show a characteristic portion of the fuel injection valve 10, FIG. 2 is a cross-sectional view showing the tip of the fuel injection valve 10, and FIG. 3 is a plan view seen from the direction of arrow II in FIG. is there.

  The fuel injection valve 10 of this embodiment is applied to a direct injection type gasoline engine, for example. The fuel injection valve 10 may be applied not only to a direct injection type gasoline engine but also to a premixed type gasoline engine or a diesel engine.

  When the fuel injection valve is applied to a direct-injection gasoline engine, the fuel injection valve 10 is mounted on the cylinder head of the engine so that the tip end portion thereof is exposed in the combustion chamber of the engine.

  The fuel injection valve 10 is a fuel injection device that directly injects fuel into the combustion chamber of the engine. The fuel injection valve 10 is supplied with fuel pressurized to a fuel injection pressure by a fuel supply pump such as a high-pressure supply pump (not shown). The fuel pressure is set to a predetermined pressure in the range of 1 MPa to 40 MPa, and the fuel injection valve 10 injects fuel at a fuel injection pressure corresponding to the range into the combustion chamber.

  As shown in FIG. 1, the housing 11 of the fuel injection valve 10 is formed in a cylindrical shape. The housing 11 has a first magnetic part 12, a nonmagnetic part 13, and a second magnetic part 14. The nonmagnetic part 13 prevents a magnetic short circuit between the first magnetic part 12 and the second magnetic part 14. The 1st magnetic part 12, the nonmagnetic part 13, and the 2nd magnetic part 14 are integrally connected by laser welding etc., for example.

  An inlet member 15 is installed at one end of the housing 11 in the axial direction. The inlet member 15 is fixed to the inner peripheral side of the housing 11 by press fitting or the like. The inlet member 15 has a fuel inlet 16. The fuel inlet 16 is supplied with fuel (in this embodiment, gasoline fuel) by the fuel supply pump. The fuel supplied to the fuel inlet 16 flows into the inner peripheral side of the housing 11 through a fuel filter 17 that removes foreign matter.

  A nozzle holder 20 is installed at the other end of the housing 11. The nozzle holder 20 is formed in a cylindrical shape, and a nozzle body 21 as a “valve body” is installed inside the nozzle holder 20. The nozzle body 21 is formed in a bottomed cylindrical shape, and is fixed to the nozzle holder 20 by, for example, press fitting or welding. The nozzle body 21 has an inner peripheral surface 21a formed in a bottomed cylindrical shape, which is formed on a conical inner wall surface 22 whose inner diameter is reduced as it approaches the tip as shown in FIG. Has a valve seat 23. A bottom 27 is provided at the lower end of the valve seat 23.

  The bottom 27 has a plurality of (for example, six in this embodiment) nozzle holes 25 that penetrate the nozzle body 21 and open to the inner wall surface 22 and the outer wall surface 24. The fuel supplied to the fuel inlet 16 is injected from the nozzle hole 25 into the combustion chamber of the engine cylinder.

  The nozzle hole 25 has a circular opening from the inlet 25b to the outlet 25a, and has a circular cross section perpendicular to the central axis of the nozzle 25. The nozzle hole 25 is not limited to this, and the opening shape may be a slit shape, and the cross section perpendicular to the central axis of the nozzle hole 25 may be flat.

  In the present embodiment, six nozzle holes 25 are formed as shown in FIG. The number of nozzle holes 25 to be formed, the direction of the central axis of the nozzle holes 25, and the size of the opening of the nozzle holes 25 may be appropriately determined according to the required characteristics of the engine to be mounted.

  As illustrated in FIG. 3, the inlet portions 25 b of the plurality of nozzle holes 25 are arranged on the same virtual circle K. That is, the plurality of nozzle hole inlet portions 25b are arranged on the virtual circle K in a single annular shape. The center of the imaginary circle K coincides with the central axis of the so-called fuel injection valve 10 and is substantially the same as the central axis J1 of the housing 11, the nozzle holder 20 and the nozzle body 21 (hereinafter simply referred to as “the central axis J1 of the nozzle body 21”). Match.

  Further, the pitch between the inlet portions 25 b of the adjacent nozzle holes 25 is formed on the virtual circle K at substantially equal pitch.

Further, the housing 11, the nozzle holder 20, and the nozzle body 21 constitute a valve body that forms a storage chamber therein. A needle 30 as a “valve member” is accommodated in the accommodation room. The needle 30 is accommodated in the housing 11, the nozzle holder 20, and the nozzle body 21 so as to be reciprocally movable in the axial direction.

  The needle 30 is disposed substantially coaxially with the nozzle body 21. The needle 30 includes a shaft portion 31, a head portion 32, a seat portion 33, and a tip portion 34. The head portion 32 is located at the end portion of the shaft portion 31 on the fuel inlet 16 side in the axial direction, and the seat portion 33 is located at the end portion of the shaft portion 31 on the nozzle hole 25 side. The seat portion 33 can be brought into contact with and separated from the valve seat 23 of the nozzle body 21 as shown in FIG. The front end portion 34 has a conical shape that extends inwardly from the lower end of the seat portion 33.

  A fuel passage 26 through which fuel flows is formed between the outer peripheral surface 30 a of the needle 30 and the inner peripheral surface 21 a of the nozzle body 21, and the fuel passage 26 is provided so as to communicate with the injection hole 25. In the fuel passage 26, the seat portion 33 and the valve seat 23 are separated and seated, so that the fuel flowing to the nozzle hole 25 is blocked and allowed.

  Moreover, the fuel injection valve 10 is provided with the drive part 40 which drives the needle 30 as shown in FIG. The drive unit 40 includes a spool 41, a coil 42, a fixed core 43, a plate housing 44, and a movable core 50. The spool 41 is installed on the outer peripheral side of the housing 11. The spool 41 is formed of a resin material in a cylindrical shape, and a coil 42 is wound on the outer peripheral side. Both ends of the wound coil 42 are electrically connected to the terminal portion 46 of the connector 45. A fixed core 43 is installed on the inner peripheral side of the coil 42 with the housing 11 in between. The fixed core 43 is formed in a cylindrical shape from a magnetic material such as iron, and is fixed to the inner peripheral side of the housing 11 by, for example, press fitting. The plate housing 44 is made of a magnetic material and covers the outer peripheral side of the coil 42.

  The movable core 50 is disposed on the same axis as the fixed core 43 and can reciprocate in the axial direction on the inner peripheral side of the housing 11. The movable core 50 is formed in a cylindrical shape from a magnetic material such as iron. The movable core 50 has a cylindrical portion 51 on the side opposite to the fixed core 43, and the head portion 32 of the needle 30 is press-fitted into the cylindrical portion 51. Thereby, the needle 30 and the movable core 50 are integrally connected, for example, by welding or the like, and can cooperate with each other.

  The movable core 50 is provided with a spring 18 made of an elastic material as an “urging member” at the end on the fixed core 43 side. The spring 18 has a force in a direction extending in the axial direction (hereinafter referred to as an urging force), and is disposed so that both ends of the spring 18 are sandwiched between the movable core 50 and the adjusting pipe 19. The spring 18 presses the movable core 50 and the needle 30 in the direction of seating on the valve seat 23. Further, the adjusting pipe 19 is structured to be fixed to the fixed core 43 by, for example, press-fitting, and by adjusting the press-fitting amount of the adjusting pipe 19 press-fitted to the fixed core 43, the spring 18 The biasing force (load) is adjusted.

  When the coil 42 is not energized, the needle 30 integrated with the movable core 50 is pressed toward the valve seat 23, and the seat portion 33 is seated on the valve seat 23. As a result, fuel injection from the nozzle hole 25 is blocked. When the coil 42 is energized, the movable core 50 is attracted by the fixed core 43, the needle 30 is separated from the valve seat 23, and fuel is injected from the injection hole 25.

  Here, the state in which the needle 30 is separated from the valve seat 23 is referred to as when the needle 30 is lifted. The lift amount of the needle 30 is determined by the air gap between the magnetic pole surfaces of the movable core 50 and the fixed core 43.

  The basic configuration of the fuel injection valve 10 has been described above. Hereinafter, a characteristic configuration of the fuel injection valve 10 will be described.

(Characteristic configuration of the fuel injection valve 10)
The fuel passage 26 is formed between the inner peripheral surface of the valve bodies 11, 20, and 21 and the outer peripheral surface of the needle 30, and refers to a passage through which fuel flows. The fuel passage 26 will be described with reference to FIGS. 2 and 3 below. The term “fuel passage 26” simply means a passage formed between the inner peripheral surface 21 a of the nozzle body 21 and the outer peripheral surface 30 a of the needle 30.

  As shown when the fuel injection valve 10 in FIG. 2 is closed and when the fuel injection valve 10 is opened in FIG. 4, the fuel passage 26 is formed between the inner peripheral surface 21 a of the nozzle body 21 and the outer peripheral surface 30 a of the needle 30. A fuel passage portion extending in the axial direction of the fuel injection valve 10 is referred to as a first fuel passage 26 a, and is formed between the conical inner wall surface 22 and the bottom portion 27, and the seat portion 33 and the tip portion 34 of the needle 30. The passage portion is referred to as a second fuel passage 26b. Here, when the fuel injection valve 10 is closed means that the seat portion 33 of the needle 30 is seated on the valve seat 23 of the nozzle body 21, and when the fuel injection valve 10 is opened, the seat portion This means that 33 is separated from the valve seat 23.

  The first fuel passage 26 a is formed as an annular passage extending in the axial direction, and the second fuel passage 26 b extends inward from the downstream end of the first fuel passage 26 a and communicates with the plurality of injection holes 25. Formed.

  Further, the second fuel passage 26 b has a recess 70 formed in the bottom portion 27 on the downstream side of the valve seat 23 and the seat portion 33 for blocking and allowing the fuel flowing through the fuel passage 26. When the seat portion 33 is separated from the valve seat 23, the main flow direction of the fuel flowing out to the recess 70 is the diameter-reducing direction of the valve seat 23 in the inner wall surface 22 whose diameter is reduced toward the fuel downstream side. Almost decided. An inlet 25b of the injection hole 25 is formed in the recess 70, and the recess 70 surrounds the periphery of the inlet 25b of the injection hole 25.

  A recess 70 that is recessed toward the nozzle hole 25 is formed between the conical inner wall surface 22 and the inlet 25b of the nozzle hole 25. The recess 70 is always in communication with the nozzle hole 25 formed for each recess 70, and has a “suck chamber” function as a fuel reservoir for storing fuel flowing into the inlet 25 b of the nozzle hole 25.

  Here, the structure of the seat portion and the valve seat 23 is configured as follows. That is, the needle 30 has a seat angle α, which is a sandwich angle of the seat surface 33a of the seat portion 33, set in a range of 80 ° to 130 °, for example. Further, the nozzle body 21 is formed such that the sandwiching angle θ of the valve seat 23 on which the seat portion 33 is seated and separated is substantially the same as or slightly smaller than the seat angle α.

  Further, the sandwiching angle β of the leading end surface 34a of the leading end portion 34 connected to the downstream end of the seat surface 33a is formed to be substantially the same as or slightly larger than the seat angle α.

  The sandwiching angle β of the distal end surface 34 a of the distal end portion 34 is substantially the same as or slightly smaller than the sandwiching angle θ of the valve seat 23. In other words, when the valve of FIG. 2 is closed, the clearance between the distal end surface 34a of the distal end portion 34 of the needle 30 and the inner wall surface 22 of the nozzle body 21 is only a slight clearance, and therefore the recess 70 is substantially formed by the distal end surface 34a. Is blocked. Thus, when the fuel injection valve 10 is closed, the fuel flow from the fuel passage 26 to the recess 70 is blocked, and the fuel flow between the recesses 70, that is, between the nozzle holes 25 is substantially blocked. .

  With such a configuration, it is possible to avoid the recess 70 being configured as a “common suck chamber” that communicates between the nozzle holes 25 as in the prior art. Therefore, the breathing action in which the combustion gas in the combustion chamber flows into the recess 70 when the fuel injection valve 10 is closed can be suppressed.

  On the other hand, when the fuel injection valve 10 is opened, as shown in FIG. 4, the second fuel passage 26 b is guided to the injection hole 25, and the flow area of the second fuel passage 26 b is determined by the recess 70. The flow path area of the portion where the fuel flows into the inlet 25b of the nozzle hole 25 is enlarged. Therefore, even if the needle 30 is a small lift when the valve is opened, the flow passage area is not restricted at the portion where the fuel flows into the injection hole inlet 25b.

  As shown in FIGS. 2 and 3, it is preferable that the inlet portion 25 b of the injection hole 25 is displaced with respect to the recess 70 in the reduced diameter direction of the valve seat 23.

  According to this, since the concave portion 70 is displaced in the counter-reducing diameter direction of the valve seat 23 with respect to the injection hole inlet portion 25b, it is easy to enlarge the flow path cross-sectional area on the upstream side among the peripheral sides of the concave portion 70. Become. For this reason, it is possible to easily reduce the flow passage cross-sectional area of the portion where the fuel flows into the injection hole inlet 25b.

  Moreover, in this embodiment, the recessed part 70 is cyclically | annularly arrange | positioned over the location where the nozzle hole 25 is located.

  According to this, the recessed part 70 surrounding the injection hole inlet 25b can be configured to be easily arranged on the side opposite to the diameter of the valve seat 23, in other words, on the side of the seat 33 that is seated on and away from the valve seat 23. . Thereby, the structure which suppresses that the flow-path cross-sectional area of the part into which a fuel flows into the nozzle hole entrance part 25b is restrict | squeezed can be implement | achieved reliably.

  In the present embodiment described above, the concave portion 70 surrounding the inlet portion 25b is provided in the inlet portion 25b of the nozzle hole 25. Therefore, the concave portion 70 is formed for each nozzle hole 25. Thereby, when the seat portion 33 of the needle 30 is seated on the valve seat 23, the space between the inlet portions 25 b of the plurality of injection holes 25 can be substantially blocked by the distal end surface 34 a of the distal end portion 34 of the needle 30. Therefore, the breathing action in which the combustion gas in the combustion chamber flows into the recess 70 is suppressed, and as a result, the generation of deposits can be suppressed.

  Further, when the seat portion 33 of the needle 30 is separated from the valve seat 23, the flow passage cross-sectional area of the fuel passage 26 portion that guides the fuel to the injection hole 25 can be enlarged by the concave portion 70, so that the needle 30 is slightly lifted. Even so, the cross-sectional area of the flow path is not restricted.

  According to the fuel injection valve 10 according to the present embodiment as described above, it is possible to suppress both the reduction of the flow passage cross-sectional area of the fuel passage leading the fuel to the injection hole 25 and the generation of deposits. is there.

  In the present embodiment described above, it is preferable that the bottom portion 27 corresponding to the top portion of the tip end portion 34 is provided with a corner 80 that is recessed with respect to the inner wall surface 22.

  According to this, when the seat portion 33 of the needle 30 is seated on the valve seat 23, it is possible to prevent the top portion of the distal end portion 34 from interfering with the conical inner wall surface 22.

  Further, in the fuel injection valve 10 having such a recess 70 and the corner 80, as a molding method of the nozzle body 21, a molding method such as hot or cold forging or sintering by injection molding powder metallurgy is used. It is preferable to apply. Thereby, the fuel injection valve 10 excellent in productivity can be achieved.

(Second Embodiment)
A second embodiment is shown in FIG. The second embodiment is a modification of the first embodiment. FIG. 5 shows a part of the fuel injection valve 10 and shows a structure relating to a characteristic part of the fuel injection valve 10.

  As shown in FIG. 5, the upstream side of the peripheral sides of the recess 70 is formed in an arc shape with a predetermined interval with respect to the outer diameter of the seat portion 33.

  According to this, since the upstream side of the recess 70 can be expanded toward the seat portion 33 within a predetermined interval, it is possible to effectively increase the flow path cross-sectional area on the upstream side.

  As a result, the fuel injection valve 10 according to the present embodiment can be configured such that the cross-sectional area of the flow path is not easily reduced when the fuel injection valve 10 is opened, as compared with the fuel injection valve 10 according to the first embodiment.

(Other embodiments)
Although a plurality of embodiments of the present invention have been described above, the present invention is not construed as being limited to these embodiments, and can be applied to various embodiments without departing from the scope of the present invention. .

  (1) In this embodiment described above, the recess 70 is provided in the nozzle body 21. The component for providing the concave portion 70 is not limited to the nozzle body 21, and the nozzle body may be constituted by an injection forming member that forms the injection hole 25 and a nozzle body main body, and is constituted by a nozzle body, a housing, or the like. The concave body 70 may be integrally provided in the valve body.

  (2) Further, in the present embodiment described above, the recess 70 is provided for each nozzle hole 25 so as to surround the periphery of the nozzle hole inlet 25b. The recess 70 is not limited to this, and may be any component as long as it does not have a common sac chamber function for each nozzle hole and has a sack chamber function independent for each nozzle hole.

10 Fuel Injection Valve 11 Housing (Valve Body)
20 Nozzle holder (valve body)
21 Nozzle body (valve body)
21a inner peripheral surface 22 inner wall surface 23 valve seat 24 outer wall surface 25 nozzle hole 25a outlet portion 25b inlet portion 26 fuel passage 26a first fuel passage 26b second fuel passage 27 bottom portion 30 needle (valve member)
30a Outer peripheral surface 33 Sheet portion 33a Sheet surface 34 Tip portion 34a Tip surface 70 Recessed portion 80 Corner portion

Claims (4)

An inner wall surface that forms a fuel passage and is reduced in diameter toward the downstream side of the fuel, a valve seat that is formed on the inner wall surface, and a plurality of injection holes that inject fuel flowing out from the downstream side of the valve seat With a valve body,
In a fuel injection valve comprising: a needle that stops and allows fuel injection from the nozzle hole by being seated and separated from the valve seat;
The valve body includes
The plurality of nozzle holes are formed in the valve seat,
And the fuel injection valve characterized by the recessed part surrounding the said inlet part provided in the circumference | surroundings of the inlet part of the said injection hole.   2. The fuel injection valve according to claim 1, wherein the inlet portion of the injection hole is deviated from the concave portion in a diameter reducing direction of the valve seat.   3. The fuel injection valve according to claim 1, wherein the concave portion is annularly arranged over a portion where the injection hole is located. 4.   The upstream side of the peripheral side of the recess is formed in an arc shape having a predetermined interval with respect to the outer diameter of the seat portion of the needle seated on and away from the valve seat. Item 4. The fuel injection valve according to Item 3.

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