Fuel injection device

Abstract

To provide a fuel injection device which can suppress variation in radial positions of a floating plate and thus suppressing variation in an injection amount.SOLUTION: A floating plate 60 permits or blocks a communication between an in-orifice passage 502 and a pressure control chamber 500 by reciprocating inside an end part of an orifice plate 50 side of a cylinder 40 to separate from or contact an orifice plate body 51. The cylinder 40 includes: an annular groove 42 forming an annular space 420 from an outer peripheral wall of the floating plate 60 by being radially outwardly recessed from an inner peripheral wall of an end part on the orifice plate 50 side; and a guide part 43 which can guide the reciprocation of the floating plate 60 by sliding with the outer peripheral wall of the floating plate 60 on an opposite side to the orifice plate 50 of the groove 42.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a fuel injection device.

Background Art

[0002] In recent years, from the viewpoint of fuel regulations, in order to achieve an increase in injection rate for the purpose of shortening the combustion period, it has become necessary to increase the fuel flow rate in the nozzle orifice. However, in a fuel injection device as described in Patent Document 1, for example, it has been found that when the orifice flow rate in the nozzle orifice is increased, the variation in the injection amount becomes large. As a result of analyzing the injection rate characteristics, which are the injection amount per unit time, it has been found that the cause is the large variation in the injection end timing, that is, the valve closing timing of the nozzle needle.

[0003] The valve closing timing of the nozzle needle is controlled by the fuel inflow timing and the inflow rate to the pressure control chamber. The fuel inflow timing is controlled by the opening and closing valve of the floating plate, that is, the up and down movement, and the inflow rate is controlled by the in-orifice passage. The floating plate is housed in the cylinder, but the gap between the outer peripheral wall of the floating plate and the inner peripheral wall of the cylinder is used as a fuel passage, and in order to move the floating plate up and down smoothly even if the inner diameter of the cylinder is reduced according to the fuel pressure, it is necessary to ensure a large radial clearance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the fuel injection device of Patent Document 1, since the clearance between the outer peripheral wall of the floating plate and the inner peripheral wall of the cylinder is large, there is a possibility that the radial position varies when the floating plate descends at each injection. Structurally, the opening on the pressure control chamber side of the in-orifice passage is formed at a position eccentric with respect to the center of the pressure control chamber. Therefore, the inflow rate into the pressure control chamber varies due to the throttling effect depending on the radial position of the floating plate, and as a result, the variation in the injection amount may increase.

[0006] An object of the present invention is to provide a fuel injection device capable of suppressing variations in the radial position of a floating plate and suppressing variations in the injection amount.

Means for Solving the Problems

[0007] The present invention is a fuel injection device that injects high-pressure fuel accumulated in a pressure accumulation pipe (2) into an internal combustion engine, and includes a nozzle body (20), a nozzle needle (30), a cylinder (40), an orifice plate (50), and a floating plate (60). The nozzle body has a nozzle chamber (200) into which high-pressure fuel flows, and a nozzle hole (23) that communicates with the nozzle chamber and injects high-pressure fuel. The nozzle needle is provided so as to be reciprocally movable within the nozzle chamber, opens and closes the space between the nozzle chamber and the nozzle hole with one end, and intermittently injects high-pressure fuel from the nozzle hole.

[0008] The cylindrical cylinder is provided so as to be axially movable relative to the nozzle needle on the radially inner side of the end portion of the nozzle body opposite to the injection holes. The orifice plate is provided on the side opposite to the injection holes of the nozzle body, and includes an orifice plate body (51) that forms a pressure control chamber (500) between the inside of the cylinder and the other end of the nozzle needle, and an in-orifice passage (502) that opens on the surface of the orifice plate body on the pressure control chamber side and is capable of supplying high-pressure fuel to the pressure control chamber. The floating plate reciprocates inside the end portion of the cylinder on the orifice plate side and allows or blocks communication between the in-orifice passage and the pressure control chamber by moving away from or contacting the orifice plate body.

[0009] The cylinder has an annular groove (42) that forms an annular space (420), which is an annular space, between the inner peripheral wall of the end portion on the orifice plate side and the outer peripheral wall of the floating plate by being recessed radially outward, and a guide portion (43) that can guide the reciprocating movement of the floating plate by sliding on the outer peripheral wall of the floating plate on the side opposite to the orifice plate of the groove. When fuel flows into the annular space formed by the groove, even if a radial misalignment occurs when the floating plate descends, a fluid acting force acts in the direction of centering the floating plate, and variations in the radial position of the floating plate can be suppressed. As a result, the inflow rate into the pressure control chamber is stabilized, and variations in the injection amount can be suppressed.

Brief Description of the Drawings

[0010]

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Figure 21

Embodiments for Carrying out the Invention

[0011] Hereinafter, a fuel injection device according to a plurality of embodiments will be described with reference to the drawings. In the plurality of embodiments, substantially the same constituent parts are denoted by the same reference numerals, and the description thereof will be omitted.

[0012] (First Embodiment) The fuel injection device of the first embodiment is shown in FIG. 1. The fuel injection device 1 is applied to, for example, a four-cylinder diesel engine mounted on a vehicle (not shown). The fuel injection device 1 is provided in each cylinder and is connected to a common rail 2 that stores diesel oil as pressurized fuel. The fuel injection device 1 injects the high-pressure fuel supplied from the common rail 2 into the combustion chamber of each cylinder. That is, the fuel injection device 1 is a fuel injection device that injects the high-pressure fuel accumulated in the common rail 2 as a "pressure accumulation pipe" into the diesel engine as an "internal combustion engine".

[0013] <1>As shown in FIGS. 1 and 2, the fuel injection device 1 includes a nozzle body 20, a nozzle needle 30 as a "valve member", a cylinder 40, an orifice plate 50, a floating plate 60, an injector body 70, a retaining nut 80, an opening / closing part 90, etc. The nozzle body 20 has a nozzle chamber 200 into which high-pressure fuel flows, and a nozzle hole 23 that communicates with the nozzle chamber 200 and injects the high-pressure fuel. The nozzle needle 30 is provided so as to be reciprocally movable within the nozzle chamber 200, opens and closes the space between the nozzle chamber 200 and the nozzle hole 23 with one end, and interrupts the injection of the high-pressure fuel from the nozzle hole 23.

[0014] The cylindrical cylinder 40 is provided so as to be axially relatively movable with respect to the nozzle needle 30 on the radially inner side of the end portion of the nozzle body 20 opposite to the nozzle hole 23. The orifice plate 50 is provided on the side opposite to the nozzle hole 23 of the nozzle body 20, and includes an orifice plate body 51 that forms a pressure control chamber 500 between the inside of the cylinder 40 and the other end portion of the nozzle needle 30, and an in-orifice passage 502 that opens on the surface of the orifice plate body 51 on the pressure control chamber 500 side and through which high-pressure fuel can be supplied to the pressure control chamber 500. The floating plate 60 reciprocates inside the end portion of the cylinder 40 on the orifice plate 50 side, and allows or blocks communication between the in-orifice passage 502 and the pressure control chamber 500 by moving away from or contacting the orifice plate body 51.

[0015] The cylinder 40 has an annular groove 42 that is recessed radially outward from the inner peripheral wall of the end portion on the orifice plate 50 side and forms an annular space 420, which is an annular space, between the cylinder 40 and the outer peripheral wall of the floating plate 60, and a guide portion 43 that can guide the reciprocating movement of the floating plate 60 by sliding on the outer peripheral wall of the floating plate 60 on the side opposite to the orifice plate 50 of the groove 42.

[0016] Hereinafter, the configuration of the fuel injection device 1 will be described in more detail.

[0017] As shown in FIG. 1, the nozzle body 20 has a nozzle cylinder portion 21, a nozzle bottom portion 22, and a nozzle hole 23. The nozzle cylinder portion 21 is formed of, for example, metal. The nozzle cylinder portion 21 has a nozzle small-diameter portion 211 and a nozzle large-diameter portion 213. The nozzle small-diameter portion 211 is formed in a substantially cylindrical shape. The nozzle large-diameter portion 213 is formed in a substantially cylindrical shape integrally with the nozzle small-diameter portion 211 so as to connect to one end of the nozzle small-diameter portion 211. The outer diameter of the nozzle large-diameter portion 213 is larger than the outer diameter of the nozzle small-diameter portion 211. The inner diameter of the nozzle large-diameter portion 213 is larger than the inner diameter of the nozzle small-diameter portion 211. The inner peripheral wall of the nozzle small-diameter portion 211 and the inner peripheral wall of the nozzle large-diameter portion 213 are connected by a tapered wall surface.

[0018] The nozzle bottom 22 is integrally formed with the nozzle cylinder part 21 so as to close the end of the nozzle small-diameter part 211 of the nozzle cylinder part 21 on the side opposite to the nozzle large-diameter part 213. The injection holes 23 are formed so as to penetrate the nozzle bottom 22. For example, a plurality of injection holes 23 are formed at equal intervals in the circumferential direction of the nozzle bottom 22. The inner wall on the upstream side with respect to the injection holes 23 of the nozzle bottom 22 is formed in a tapered shape, forming a tapered valve seat 220.

[0019] The nozzle chamber 200 is formed inside the nozzle cylinder part 21 and the nozzle bottom 22 and communicates with the injection holes 23.

[0020] The nozzle needle 30 has a needle body 31 and a flange part 32. The needle body 31 is formed in a rod shape by, for example, metal. The needle body 31 is provided in the nozzle chamber 200 so as to be reciprocally movable in the axial direction. The needle body 31 is provided in the nozzle chamber 200 such that one end thereof can contact or separate from the valve seat 220. Hereinafter, the direction in which the needle body 31 contacts the valve seat 220 is appropriately referred to as the "valve closing direction", and the direction in which the needle body 31 separates from the valve seat 220 is referred to as the "valve opening direction".

[0021] The flange part 32 is formed in an annular shape by, for example, metal and is provided at a position separated by a predetermined distance from the end of the needle body 31 on the side opposite to the injection holes 23. In a state where one end of the needle body 31 contacts the valve seat 220, the flange part 32 is located radially inside the end of the nozzle large-diameter part 213 on the nozzle small-diameter part 211 side. Also, in this state, the end face of the other end of the needle body 31 is separated from the end face of the nozzle large-diameter part 213 on the side opposite to the nozzle small-diameter part 211 by a predetermined distance toward the injection holes 23 side.

[0022] As shown in FIG. 2, inside the nozzle large-diameter portion 213 in the radial direction, a cylinder 40, a needle spring 33, a floating plate 60, and a support spring 36 as a "spring" are provided. The cylinder 40 is formed in a cylindrical shape, for example, by metal. The cylinder 40 is provided on the outer side in the radial direction of the end portion of the needle body 31 on the side opposite to the nozzle hole 23.

[0023] As shown in FIG. 2, the cylinder 40 has a cylinder sliding portion 411. The cylinder sliding portion 411 is formed on the inner peripheral wall of the end portion of the cylinder 40 on the nozzle needle 30 side. The cylinder 40 is provided such that the cylinder sliding portion 411 is slidable with the outer peripheral wall of the end portion of the needle body 31 on the side opposite to the nozzle hole 23 and is relatively movable in the axial direction with respect to the needle body 31. The outer diameter of the cylinder 40 is smaller than the inner diameter of the nozzle large-diameter portion 213. A substantially cylindrical gap is formed between the outer peripheral wall of the cylinder 40 and the inner peripheral wall of the nozzle large-diameter portion 213.

[0024] The needle spring 33 is, for example, a coil spring and is provided between the flange portion 32 and the cylinder 40 on the outer side in the radial direction of the needle body 31. One end of the needle spring 33 abuts against the flange portion 32, and the other end abuts against the cylinder 40. The needle spring 33 has a force that extends in the axial direction. Thereby, the needle spring 33 biases the cylinder 40 in the valve-opening direction with respect to the needle body 31.

[0025] The floating plate 60 has a plate body 61 and a plate orifice passage 601. The plate body 61 is formed in a substantially disc shape, for example, by metal. The plate body 61 is provided so as to be reciprocally movable in the axial direction inside the radial direction of the end portion of the cylinder 40 on the side opposite to the nozzle needle 30. The plate orifice passage 601 is formed so as to penetrate the center of the plate body 61 in the plate thickness direction. The plate orifice passage 601 has a plate orifice 602 formed in an orifice shape in the middle of the axial direction.

[0026] The support spring 36 is, for example, a coil spring, and is provided between a spring seat portion 412, which is a portion extending radially inward from the inner peripheral wall of the cylinder 40, and the floating plate 60. One end of the support spring 36 abuts against the spring seat portion 412, and the other end abuts against the floating plate 60. The support spring 36 has a force that extends in the axial direction. Thereby, the support spring 36 biases the floating plate 60 in the valve opening direction with respect to the cylinder 40.

[0027] The orifice plate 50 is provided on the side opposite to the nozzle holes 23 with respect to the nozzle body 20. The orifice plate 50 has an orifice plate main body 51, a supply passage 501, an in-orifice passage 502, an out passage 503, a plate annular recess 52, a plate annular passage 53, a plate recess 54, and the like. The orifice plate main body 51 is formed in a substantially disc shape by, for example, metal. The end face of the orifice plate main body 51 on the side of the nozzle holes 23 is provided so as to abut against the end face of the nozzle large diameter portion 213 of the nozzle small diameter portion 211 on the opposite side.

[0028] As shown in FIGS. 1 and 2, the supply passage 501 is inclined with respect to the axis of the orifice plate main body 51 at the outer edge portion of the orifice plate main body 51, and is formed so as to connect the end face of the orifice plate main body 51 on the side opposite to the nozzle holes 23 and the end face on the side of the nozzle holes 23. The in-orifice passage 502 is inclined with respect to the axis of the orifice plate main body 51, and is formed so as to connect the end face of the orifice plate main body 51 on the side opposite to the nozzle holes 23 and the center of the end face on the side of the nozzle holes 23. An orifice-shaped in-orifice 504 is formed at the end portion on the side of the nozzle holes 23 of the in-orifice passage 502. Here, the end portion of the in-orifice passage 502 on the side opposite to the nozzle holes 23 is adjacent to the end portion of the supply passage 501 on the side opposite to the nozzle holes 23. The out passage 503 is inclined with respect to the axis of the orifice plate main body 51, and is formed so as to connect the end face of the orifice plate main body 51 on the side opposite to the nozzle holes 23 and the approximate center of the end face on the side of the nozzle holes 23. The end portion of the out passage 503 on the side opposite to the nozzle holes 23 is formed in an orifice shape.

[0029] As shown in Fig. 2, the plate annular recess 52 is formed to be annularly recessed from the end face on the orifice 23 side of the orifice plate body 51. The plate annular recess 52 is connected to the end of the supply passage 501 on the orifice 23 side. The plate annular passage 53 is formed to be annularly recessed from the end face on the orifice 23 side of the orifice plate body 51 inside the radial direction of the plate annular recess 52. The plate annular passage 53 is connected to the in-orifice 504. The plate recess 54 is formed to be circularly recessed from the center of the end face on the orifice 23 side of the orifice plate body 51 inside the radial direction of the plate annular passage 53. The plate recess 54 is connected to the end of the out passage 503 on the orifice 23 side.

[0030] The end face of the cylinder 40 on the side opposite to the orifice 23 can be in contact with or separated from the end face on the orifice 23 side of the orifice plate body 51. The pressure control chamber 500 is formed between the inner peripheral wall of the cylinder 40 and the end of the needle body 31 on the side opposite to the orifice 23 and the end face on the orifice 23 side of the orifice plate body 51.

[0031] The end of the supply passage 501 on the orifice 23 side communicates with the nozzle chamber 200 through the plate annular recess 52. The end of the in-orifice passage 502 on the orifice 23 side, that is, the in-orifice 504, communicates with the pressure control chamber 500 through the plate annular passage 53. The end of the out passage 503 on the orifice 23 side communicates with the pressure control chamber 500 through the plate recess 54.

[0032] The injector body 70 is provided on the side opposite to the orifice 23 with respect to the orifice plate 50. The injector body 70 has a body main body 71, a body screw portion 72, a pipe connection portion 73, and a high-pressure fuel passage 701. The body main body 71 is formed in a cylindrical shape by, for example, metal. The body main body 71 is provided such that the end face on the orifice 23 side abuts against the end face on the side opposite to the orifice 23 of the orifice plate body 51. The body screw portion 72 is formed on the outer peripheral wall of the end of the body main body 71 on the orifice 23 side.

[0033] The high-pressure fuel passage 701 is formed between the inner peripheral wall and the outer peripheral wall of the body main body 71 so as to be substantially parallel to the axis of the body main body 71. The high-pressure fuel passage 701 opens at a position corresponding to the openings of the supply passage 501 and the in-orifice passage 502 on the end face of the body main body 71 on the side of the injection hole 23. Thereby, the high-pressure fuel passage 701 communicates with the supply passage 501 and the in-orifice passage 502.

[0034] The pipe connection portion 73 is formed at the end portion of the body main body 71 on the side opposite to the injection hole 23 (see FIG. 1). Inside the pipe connection portion 73, a passage 731 communicating with the high-pressure fuel passage 701 is formed. A fuel pipe extending from the common rail 2 is connected to the pipe connection portion 73. Thereby, the high-pressure fuel supplied from the common rail 2 flows into the high-pressure fuel passage 701 via the passage 731 in the pipe connection portion 73. The fuel flowing into the high-pressure fuel passage 701 flows into the nozzle chamber 200 via the supply passage 501 and flows into the pressure control chamber 500 via the in-orifice passage 502. As a result, the nozzle chamber 200 and the pressure control chamber 500 are filled with high-pressure fuel.

[0035] The opening / closing portion 90 is provided inside the end portion of the body main body 71 on the side of the injection hole 23. The opening / closing portion 90 has a drive portion 91 and a movable member 92.

[0036] The movable member 92 is provided inside the end portion of the body main body 71 on the side of the injection hole 23 so as to be reciprocally movable in a direction substantially parallel to the axis of the body main body 71. The end portion of the movable member 92 on the side of the injection hole 23 is provided so as to be able to contact or separate from a portion corresponding to the opening of the out passage 503 on the end face of the orifice plate body 51 on the side opposite to the injection hole 23.

[0037] The low-pressure side space 700 is formed radially outside the end of the movable member 92 on the orifice 23 side. The low-pressure side space 700 communicates with a low-pressure fuel passage (not shown). When the movable member 92 abuts on a portion corresponding to the opening of the out passage 503 on the end face of the orifice plate body 51 opposite to the orifice 23, the communication between the pressure control chamber 500 and the low-pressure side space 700 via the out passage 503 is blocked. On the other hand, when the movable member 92 is separated from the portion corresponding to the opening of the out passage 503 on the end face of the orifice plate body 51 opposite to the orifice 23, the communication between the pressure control chamber 500 and the low-pressure side space 700 via the out passage 503 is allowed. Thus, the opening / closing part 90 opens and closes between the pressure control chamber 500 and the low-pressure side space 700 by bringing the movable member 92 into contact with the orifice plate body 51 or separating the movable member 92 from the orifice plate body 51.

[0038] The drive part 91 is provided on the side opposite to the orifice 23 with respect to the movable member 92, generates a magnetic suction force when energized, and can suck the movable member 92 to the side opposite to the orifice 23. The ECU 100 (see FIG. 1) provided in the vehicle can control the energization of the drive part 91. The ECU 100 can control the operation of the movable member 92 of the opening / closing part 90 by controlling the energization of the drive part 91, and can control the opening and closing between the pressure control chamber 500 and the low-pressure side space 700.

[0039] The retaining nut 80 has a nut cylindrical portion 81 and a nut thread portion 83. The nut cylindrical portion 81 is formed of, for example, metal. The nut cylindrical portion 81 has a nut small-diameter portion 811, a nut medium-diameter portion 812, and a nut large-diameter portion 813. The nut small-diameter portion 811 is formed in a substantially cylindrical shape. The nut medium-diameter portion 812 is integrally formed in a substantially cylindrical shape with the nut small-diameter portion 811 so as to connect to one end of the nut small-diameter portion 811. The outer diameter of the nut medium-diameter portion 812 is the same as the outer diameter of the nut small-diameter portion 811. The inner diameter of the nut medium-diameter portion 812 is larger than the inner diameter of the nut small-diameter portion 811. The nut large-diameter portion 813 is integrally formed in a substantially cylindrical shape with the nut medium-diameter portion 812 so as to connect to the end portion of the nut medium-diameter portion 812 on the side opposite to the nut small-diameter portion 811. The outer diameter of the nut large-diameter portion 813 is the same as the outer diameter of the nut medium-diameter portion 812. The inner diameter of the nut large-diameter portion 813 is larger than the inner diameter of the nut medium-diameter portion 812.

[0040] The nut thread portion 83 is formed on the inner peripheral wall of the end portion of the nut large-diameter portion 813 on the side opposite to the nut medium-diameter portion 812 so as to be screwable with the body thread portion 72 of the injector body 70. The retaining nut 80 is provided such that the annular end face of the nut small-diameter portion 811 on the nut large-diameter portion 813 side abuts against the annular end face of the nozzle large-diameter portion 213 on the nozzle small-diameter portion 211 side, and the nut thread portion 83 is screwed onto the body thread portion 72. As a result, an axial force in the direction in which the nozzle body 20 and the injector body 70 approach each other is generated. Therefore, the orifice plate 50 is sandwiched between the nozzle body 20 and the injector body 70, and a predetermined pressure acts between the end face of the nozzle large-diameter portion 213 on the orifice plate body 51 side and the end face of the orifice plate body 51 on the nozzle large-diameter portion 213 side, and between the end face of the orifice plate body 51 on the body main body 71 side and the end face of the body main body 71 on the orifice plate body 51 side.

[0041] Next, the cylinder 40 and the surrounding configuration will be described in detail.

[0042] <1>As shown in Fig. 5, the groove 42 is recessed radially outward from the inner peripheral wall of the end portion of the cylinder 40 on the orifice plate 50 side, and forms an annular space 420, which is an annular space, between the groove 42 and the outer peripheral wall of the floating plate 60. The guide portion 43 can guide the reciprocating movement of the floating plate 60 by sliding on the outer peripheral wall of the floating plate 60 on the side opposite to the orifice plate 50 of the groove 42. On the side opposite to the groove 42 with respect to the guide portion 43, an annular relief recess 46 is formed, which is recessed radially outward from the inner peripheral wall of the cylinder 40. The floating plate 60 has a plate taper portion 62 and a plate cut surface 63. The plate taper portion 62 is formed at the end portion of the plate body 61 on the side opposite to the orifice plate 50. The plate taper portion 62 is formed in a tapered shape so as to approach the axis of the plate body 61 as it goes from the orifice plate 50 side to the side opposite to the orifice plate 50. The plate cut surface 63 is formed in a planar shape in the plate taper portion 62 so as to be inclined with respect to the axis of the plate body 61. Four plate cut surfaces 63 are formed at equal intervals in the circumferential direction of the plate body 61. The plate cut surface 63 allows the fuel on the orifice plate 50 side with respect to the plate body 61 to easily flow to the side opposite to the orifice plate 50. Note that the broken-line plate taper portion 62 in Fig. 5 shows the plate taper portion 62 when the floating plate 60 is rotated 45 degrees in the circumferential direction.

[0043] The inner diameter of the guide portion 43 is larger than the outer diameter of the floating plate 60. Therefore, a substantially cylindrical clearance is formed between the inner peripheral wall of the guide portion 43 and the outer peripheral wall of the floating plate 60. An annular and planar stepped surface 47 is formed on the radially inner side of the relief recess 46. The inner diameter of the stepped surface 47 is smaller than the outer diameter of the end surface of the floating plate 60 on the side opposite to the orifice plate 50. Therefore, the outer edge portion of the end surface of the floating plate 60 on the side opposite to the orifice plate 50 can contact the stepped surface 47, and the floating plate 60 is axially movable between the orifice plate 50 and the stepped surface 47. That is, the axial movable range of the floating plate 60 is from the position where it contacts the orifice plate 50 to the position where it contacts the stepped surface 47.

[0044] <1-1>As shown in FIG. 7, in a state where the floating plate 60 is at the position farthest from the orifice plate 50 within the axial movable range of the floating plate 60, the end portion of the outermost diameter portion of the floating plate 60 on the orifice plate 50 side is located closer to the orifice plate 50 than the end portion of the guide portion 43 on the orifice plate 50 side. At this time, the outer edge portion of the end surface of the floating plate 60 on the side opposite to the orifice plate 50 is in contact with the stepped surface 47. Even when the floating plate 60 is in contact with the stepped surface 47, the fuel in the vicinity of the relief recess 46 can flow toward the support spring 36 through the space between the plate cut surface 63 and the stepped surface 47.

[0045] <2>The groove 42 has a straight portion 421 that forms an inner peripheral wall parallel to the inner peripheral wall of the guide portion 43 (see FIG. 5).

[0046] <3>The groove 42 has a connecting portion 44 that connects the straight portion 421 and the guide portion 43. In a cross-section by a plane including the axis of the cylinder 40, the connecting portion 44 is formed to be linear (see FIG. 5). The connecting portion 44 is formed so as to approach the axis of the cylinder 40 as it goes from the straight portion 421 side toward the guide portion 43 side. Note that the angle of inclination of the connecting portion 44 with respect to the axis of the cylinder 40 is, for example, about 20 degrees.

[0047] <4>The cylinder 40 has longitudinal grooves 45 that extend along the axial direction of the cylinder 40 while being recessed radially outward from the inner peripheral wall (see FIGS. 3 and 6). As shown in FIG. 3, two longitudinal grooves 45 are formed at equal intervals in the circumferential direction of the cylinder 40. The longitudinal grooves 45 are formed so that the shape of a cross-section by a plane perpendicular to the axis of the cylinder 40 is substantially arc-shaped. As shown in FIG. 6, the longitudinal grooves 45 connect the end face on the orifice plate 50 side of the cylinder 40 and the relief recess 46.

[0048] <5>Of the two cross-sections formed when the annular space 420 is cut by a plane including the axis of the cylinder 40, one area S1 is 1 / 2 or more of the minimum flow path cross-sectional area S2 of the in-orifice passage 502 (see FIG. 5). Here, the minimum flow path cross-sectional area S2 is equal to the flow path cross-sectional area of the in-orifice 504.

[0049] <6>The support spring 36 as a "spring" is provided on the side opposite to the orifice plate 50 of the floating plate 60 and biases the floating plate 60 toward the orifice plate 50 side (see FIG. 5). For example, in a state where the support spring 36 is compressed only by the self-weight of the floating plate 60, such as before assembling when the nozzle body 20 and the orifice plate 50 are not in contact, the end portion on the support spring 36 side of the outermost diameter portion of the floating plate 60 is located on the side opposite to the groove 42 with respect to the end portion on the groove 42 side of the guide portion 43 (see FIG. 8).

[0050] <7>The orifice plate 50 has an annular groove 55 that is a concave annular groove on the side opposite to the cylinder 40 from a portion facing the annular space 420 on the end face of the orifice plate body 51 on the cylinder 40 side (see FIGS. 4 and 5). Note that the annular groove 55 is also connected and in communication with the vertical groove 45 (see FIG. 6).

[0051] Next, the operation of the fuel injection device 1 will be described.

[0052] The high-pressure fuel from the common rail 2 is supplied to the nozzle chamber 200 via the passage 731, the high-pressure fuel passage 701, the supply passage 501, and the plate annular recess 52 (see FIGS. 1 and 2). The needle spring 33 applies a closing valve direction load to the nozzle needle 30.

[0053] A part of the fuel in the high-pressure fuel passage 701 is supplied to the pressure control chamber 500 through the in-orifice 504 of the in-orifice passage 502 and the plate annular passage 53. As shown in FIG. 1, when the power supply to the drive unit 91 is off, the pressure control chamber 500 is filled with high-pressure fuel. The nozzle needle 30 receives a closing valve direction force from the load of the needle spring 33 and the fuel pressure in the pressure control chamber 500.

[0054] When the power supply to the drive unit 91 is turned on, the movable member 92 moves in the opening valve direction by the magnetic attraction force of the drive unit 91, and communication via the out passage 503 between the pressure control chamber 500 and the low-pressure side space 700 is allowed. As a result, the fuel on the nozzle needle 30 side with respect to the floating plate 60 in the pressure control chamber 500 flows to the orifice plate 50 side with respect to the floating plate 60 through the plate orifice passage 601, flows through the out passage 503 to the low-pressure side space 700, and can be discharged to the low-pressure fuel passage. As a result, the fuel pressure in the pressure control chamber 500 decreases. At this time, the floating plate 60 is pressed against the orifice plate 50 by the fuel pressure in the pressure control chamber 500 and the biasing force of the support spring 36.

[0055] When the fuel pressure in the pressure control chamber 500 decreases, the force that the nozzle needle 30 receives from the fuel pressure in the nozzle chamber 200 in the valve-opening direction becomes greater than the force that the nozzle needle 30 receives in the valve-closing direction from the load of the needle spring 33 and the fuel pressure in the pressure control chamber 500. Therefore, the nozzle needle 30 moves in the valve-opening direction and separates from the valve seat 220. As a result, the fuel in the nozzle chamber 200 is injected from the injection holes 23.

[0056] When the energization to the drive unit 91 is turned off, the movable member 92 moves in the valve-closing direction, abuts against the orifice plate 50, and the communication via the out passage 503 between the pressure control chamber 500 and the low-pressure side space 700 is blocked. Therefore, the fuel pressure in the pressure control chamber 500 rises due to the fuel supplied from the in-orifice passage 502. As a result, the force that the nozzle needle 30 receives in the valve-closing direction from the load of the needle spring 33 and the fuel pressure in the pressure control chamber 500 becomes greater than the force that the nozzle needle 30 receives from the fuel pressure in the nozzle chamber 200 in the valve-opening direction. Therefore, the nozzle needle 30 moves in the valve-closing direction and abuts against the valve seat 220. As a result, the injection of the fuel in the nozzle chamber 200 from the injection holes 23 stops. When high-pressure fuel is supplied from the in-orifice passage 502 to the pressure control chamber 500, the floating plate 60 can move toward the nozzle needle 30 against the biasing force of the support spring 36.

[0057] Next, the advantages of the present embodiment over the comparative form will be described.

[0058] As shown in FIG. 9, in the comparative form, the cylinder 40 does not have a groove 42, but instead has a tapered portion 49. The tapered portion 49 is formed in a tapered shape so as to approach the axis of the cylinder 40 as it goes from the orifice plate 50 side toward the side opposite to the orifice plate 50 at the inner edge portion of the end face of the cylinder 40 on the orifice plate 50 side.

[0059] In a fuel injection device of a comparative form, when the orifice flow rate, which is the fuel flow rate at the orifice 23, is increased, it has been found that the variation in the injection amount becomes large (see (C) in FIG. 11). When analyzing the injection rate characteristics, which are the injection amount per unit time, it has been found that the cause is the large variation in the closing timing of the injection, that is, the closing valve timing of the nozzle needle 30 (see the arrows (4) and (5) shown in FIG. 11). This is because the variation in the area, which is the product of the injection rate and time, corresponds to the variation in the injection amount, and even if the changes in (4) and (5) are the same, the larger the orifice flow rate, the larger this variation becomes (see (C) in FIG. 11).

[0060] As shown in FIG. 12, the variation in the closing valve timing of the nozzle needle 30 causes the injection rate to vary, and as a result, the variation in the injection amount occurs.

[0061] Due to the structure, the opening on the pressure control chamber 500 side of the in-orifice passage 502 is formed at a position eccentric with respect to the center of the pressure control chamber 500. As shown in FIGS. 13(A) and 13(B), when the floating plate 60 is located on the opening side of the in-orifice passage 502 with respect to the center of the pressure control chamber 500, a predetermined gap Sp1 is formed between the outer peripheral wall of the floating plate 60 and the inner peripheral wall of the cylinder 40 on the side opposite to the opening of the in-orifice passage 502 with respect to the floating plate 60. In this case, since the distance between the opening of the in-orifice passage 502 and the gap Sp1 is long, the flow rate of the fuel flowing from the in-orifice passage 502 into the pressure control chamber 500 decreases, and the pressure increase in the pressure control chamber 500 becomes slow (see (B) in FIG. 13). As a result, the closing speed of the nozzle needle 30 becomes slow (see (C) in FIG. 13).

[0062] On the one hand, as shown in FIGS. 14(A) and 14(B), when the floating plate 60 is located on the side opposite to the opening of the in-orifice passage 502 with respect to the center of the pressure control chamber 500, a predetermined gap Sp2 is formed between the outer peripheral wall of the floating plate 60 and the inner peripheral wall of the cylinder 40 on the opening side of the in-orifice passage 502 with respect to the floating plate 60. In this case, since the distance between the opening of the in-orifice passage 502 and the gap Sp2 is short, the flow rate of the fuel flowing from the in-orifice passage 502 into the pressure control chamber 500 increases, and the pressure increase in the pressure control chamber 500 becomes faster (see FIG. 14(B)). As a result, the closing speed of the nozzle needle 30 becomes faster (see FIG. 14(C)).

[0063] Further, in the comparative form, when in the states shown in FIGS. 14(A) and 14(B), since the fluid acting force of the fuel flowing into the gap Sp2 acts on the outer peripheral wall of the floating plate 60, the floating plate 60 remains in a state of being eccentric with respect to the center of the pressure control chamber 500.

[0064] On the other hand, in the present embodiment, as shown in FIGS. 15(A) and 15(B), when the floating plate 60 is located on the side opposite to the opening of the in-orifice passage 502 with respect to the center of the pressure control chamber 500, the fluid acting force of the fuel flowing from the in-orifice passage 502 into the annular space 420 of the groove 42 acts on the side opposite to the opening of the in-orifice passage 502 of the outer peripheral wall of the floating plate 60, and the floating plate 60 moves in the direction of being centered. As a result, variations in the radial position of the floating plate 60 in the pressure control chamber 500 can be suppressed. Thus, the present embodiment is advantageous in that it can suppress variations in the radial position of the floating plate 60 as compared with the comparative form.

[0065] Also, as shown in FIG. 9, in the comparative form, since the radial width of the space 490 formed between the outer peripheral wall of the floating plate 60 and the tapered portion 49 is relatively large and the axial length is relatively short, the centering effect of the floating plate 60 due to the fluid acting force of the fuel flowing into the space 490 cannot be expected. If the tapered portion 49 is formed so as to increase the axial length of the space 490 in expectation of an increase in the fluid acting force, the axial length of the guide portion 43 becomes short, and due to an increase in the inclination of the floating plate 60, there is a possibility that the variation in the injection amount increases. Further, if the outer diameter of the tapered portion 49, that is, the seal diameter R1 which is the inner diameter of the contact surface between the orifice plate body 51 and the cylinder body 41, is enlarged so as to increase the radial size of the space 490 in expectation of an increase in the fluid acting force, there is a possibility that the variation in the injection amount increases due to a decrease in the sealing function. Also, when the tapered portion 49 is formed so as to increase the axial length of the space 490 while decreasing the radial width, the tip of the space 490 becomes narrow, and due to the influence of the viscosity of the fuel, the fuel does not flow around, and it is difficult for the fluid acting force to act on the floating plate 60.

[0066] Also, in the comparative form, in a state where the floating plate 60 is at the position farthest from the orifice plate 50 within the axial movable range of the floating plate 60, the end portion on the orifice plate 50 side of the outermost diameter portion of the floating plate 60 is located at substantially the same position as the end portion on the orifice plate 50 side of the guide portion 43 (see FIG. 10). Therefore, as the floating plate 60 moves away from the orifice plate 50, the fluid acting force acting on the outer peripheral wall of the floating plate 60 from the fuel flowing into the tapered portion 49 becomes small, and in a state where the floating plate 60 is at the position farthest from the orifice plate 50, the fluid acting force acting on the outer peripheral wall of the floating plate 60 becomes substantially zero.

[0067] On the one hand, in the present embodiment, in a state where the floating plate 60 is at the position farthest from the orifice plate 50 within the axial movable range of the floating plate 60, the end portion of the outermost diameter portion of the floating plate 60 on the orifice plate 50 side is located closer to the orifice plate 50 than the end portion of the guide portion 43 on the orifice plate 50 side (see FIG. 7). Therefore, regardless of the axial position of the floating plate 60, a fluid acting force acts on the outer peripheral wall of the floating plate 60 from the fuel flowing into the annular space 420 of the groove 42, and the floating plate 60 is centered at the center of the pressure control chamber 500. Thus, compared with the comparative form, the present embodiment is advantageous in that it can suppress variations in the radial position of the floating plate 60 regardless of the axial position of the floating plate 60.

[0068] In the present embodiment, the greater the depth of the groove 42, that is, the greater the axial dimension of the groove 42, the greater the area of the surface of the outer peripheral wall of the floating plate 60 on which the centering force acts, and thus the greater the centering force acting on the floating plate 60. Therefore, the greater the depth of the groove 42, that is, the greater the axial dimension of the groove 42, the greater the amount of movement of the floating plate 60 in the centering direction.

[0069] As described above, <1> in the present embodiment, the cylinder 40 forms an annular space 420, which is an annular space, between the inner peripheral wall at the end on the orifice plate 50 side and the outer peripheral wall of the floating plate 60 by recessing radially outward. The cylinder 40 has an annular groove 42 and a guide portion 43 that can guide the reciprocating movement of the floating plate 60 by sliding on the outer peripheral wall of the floating plate 60 on the side opposite to the orifice plate 50 of the groove 42. When fuel flows into the annular space 420 formed by the groove 42, even if a radial displacement occurs when the floating plate 60 descends, a fluid acting force acts in the direction of centering the floating plate 60, and variations in the radial position of the floating plate 60 can be suppressed. Thereby, the inflow rate into the pressure control chamber 500 becomes stable, and variations in the injection amount can be suppressed.

[0070] Further, <2> in the present embodiment, the groove 42 has a straight portion 421 that forms an inner peripheral wall parallel to the inner peripheral wall of the guide portion 43. Therefore, while ensuring the guiding function by the guide portion 43, a fluid acting force acting on the floating plate 60 can also be ensured.

[0071] Further, <3> in the present embodiment, the groove 42 has a connecting portion 44 that connects the straight portion 421 and the guide portion 43. In a cross-section by a plane including the axis of the cylinder 40, the connecting portion 44 is formed to be linear. Therefore, the insertability of the floating plate 60 with respect to the cylinder 40 can be improved. Also, the workability between the connecting portion 44, the straight portion 421, and the guide portion 43 can be improved, and the generation of burrs can be suppressed.

[0072] Further, <4> in the present embodiment, the cylinder 40 has a longitudinal groove 45 that recesses radially outward from the inner peripheral wall and extends along the axial direction of the cylinder 40. By using the longitudinal groove 45 as a fuel passage, the flow rate of the fuel flowing outside the floating plate 60 in the radial direction can be ensured.

[0073] In addition, <5> in the present embodiment, of the two cross-sections formed when the annular space 420 is cut by a plane including the axis of the cylinder 40, the area S1 of one of the cross-sections is 1 / 2 or more of the minimum flow path cross-sectional area S2 of the in-orifice passage 502. Therefore, the fuel flow rate from the in-orifice passage 502 to the pressure control chamber 500 of the groove 42 can be ensured.

[0074] In addition, <6> in the present embodiment, the support spring 36 is provided on the side opposite to the orifice plate 50 of the floating plate 60, and biases the floating plate 60 toward the orifice plate 50 side. In a state where the support spring 36 is compressed only by the self-weight of the floating plate 60, the end portion on the support spring 36 side of the outermost diameter portion of the floating plate 60 is located on the side opposite to the groove 42 with respect to the end portion on the groove 42 side of the guide portion 43. Therefore, it is possible to prevent the floating plate 60 from falling off from the cylinder 40 during transportation before assembly or the like.

[0075] In addition, <7> in the present embodiment, the orifice plate 50 has an annular groove 55 that is an annular groove recessed from the portion facing the annular space 420 on the end face on the cylinder 40 side of the orifice plate body 51 toward the side opposite to the cylinder 40. Therefore, the fuel flow rate from the in-orifice passage 502 to the annular space 420 of the groove 42 can be ensured.

[0076] (Second Embodiment) A part of the fuel injection device according to the second embodiment is shown in FIG. 16. The second embodiment is different from the first embodiment in the configuration of the groove 42.

[0077] <3>In this embodiment, in a cross-section by a plane including the axis of the cylinder 40, the connecting portion 44 is formed to be linear or curved. More specifically, in a cross-section by a plane including the axis of the cylinder 40, the connecting portion 44 is formed such that the central portion is linear, and the end portions on the straight portion 421 side and the guide portion 43 side are formed to be curved. In this embodiment, the insertability of the floating plate 60 with respect to the cylinder 40 can be further improved. Further, the generation of burrs between the connecting portion 44, the straight portion 421, and the guide portion 43 can be further suppressed.

[0078] (Third Embodiment) A part of the fuel injection device according to the third embodiment is shown in FIG. 17. The third embodiment is different from the first embodiment in the configuration of the groove 42.

[0079] <3>In this embodiment, in a cross-section by a plane including the axis of the cylinder 40, the connecting portion 44 is formed to be linear. More specifically, the connecting portion 44 is formed in an annular and planar shape between the straight portion 421 and the guide portion 43 so as to be perpendicular to the axis of the cylinder 40. In this embodiment, for example, compared with the first embodiment in which the connecting portion 44 is inclined with respect to the axis of the cylinder 40, the tip of the annular space 420 formed by the groove 42 can be widened, and fuel can be made to flow around. Therefore, a fluid acting force can be further applied to the floating plate 60.

[0080] (Fourth Embodiment) A part of the fuel injection device according to the fourth embodiment is shown in FIG. 18. The fourth embodiment is different from the first embodiment in the configuration of the longitudinal groove 45.

[0081] In this embodiment, four longitudinal grooves 45 are formed at equal intervals in the circumferential direction of the cylinder 40. Therefore, the flow rate of the fuel flowing outside the floating plate 60 in the radial direction can be further ensured.

[0082] (Fifth Embodiment) A part of the fuel injection device according to the fifth embodiment is shown in FIG. 19. The fifth embodiment is different from the first embodiment in the configuration of the vertical groove 45.

[0083] In the present embodiment, the vertical groove 45 is formed such that the cross-sectional shape by a plane perpendicular to the axis of the cylinder 40 is substantially triangular.

[0084] (Sixth Embodiment) A part of the fuel injection device according to the sixth embodiment is shown in FIG. 20. The sixth embodiment is different from the first embodiment in the configuration of the vertical groove 45.

[0085] In the present embodiment, the vertical groove 45 is formed such that the cross-sectional shape by a plane perpendicular to the axis of the cylinder 40 is substantially rectangular.

[0086] (Seventh Embodiment) A part of the fuel injection device according to the seventh embodiment is shown in FIG. 21. The seventh embodiment is different from the first embodiment in the configuration of the cylinder 40, the configuration of the nozzle needle 30, the arrangement of the support spring 36, etc.

[0087] In the present embodiment, it does not have the spring seat portion 412 shown in the first embodiment. On the other hand, the nozzle needle 30 has a spring seat portion 311. The spring seat portion 311 is formed so as to be recessed from the end face on the side opposite to the nozzle hole 23 of the needle body 31 toward the nozzle hole 23 side. One end of the support spring 36 abuts on the spring seat portion 311, and the other end abuts on the floating plate 60. The support spring 36 has a force extending in the axial direction. Thereby, the support spring 36 biases the floating plate 60 in the valve opening direction with respect to the cylinder 40.

[0088] Even with the configuration of the present embodiment, the same effects as those of the first embodiment can be achieved.

[0089] (Other Embodiments) In other embodiments, the cylinder may have any number of longitudinal grooves extending along the axial direction of the cylinder while being recessed radially outward from the inner peripheral wall. Further, in other embodiments, the longitudinal grooves may have any shape in cross-section by a plane perpendicular to the axis of the cylinder. Further, in other embodiments, the cylinder may not have longitudinal grooves.

[0090] Further, in other embodiments, the groove may not have a straight portion that forms an inner peripheral wall parallel to the inner peripheral wall of the guide portion. That is, the inner peripheral wall of the groove may not be parallel to the inner peripheral wall of the guide portion.

[0091] Further, in other embodiments, the area of one of the two cross-sections formed when the annular space is cut by a plane including the axis of the cylinder may not be equal to or greater than 1 / 2 of the minimum flow path cross-sectional area of the in-orifice passage.

[0092] Further, in other embodiments, when the spring is compressed only by the weight of the floating plate, the end of the outermost diameter portion of the floating plate on the spring side may not be located on the side opposite to the groove with respect to the end of the guide portion on the groove side.

[0093] Further, in other embodiments, the orifice plate may not have an annular groove which is an annular groove recessed from the portion of the end face on the cylinder side of the orifice plate body facing the annular space to the side opposite to the cylinder.

[0094] The features of the present disclosure are shown as follows. "Disclosure 1" A fuel injection device that injects high-pressure fuel accumulated in a pressure accumulation pipe (2) into an internal combustion engine, A nozzle body (20) having a nozzle chamber (200) into which the high-pressure fuel flows and a nozzle hole (23) communicating with the nozzle chamber and injecting the high-pressure fuel, A nozzle needle (30) provided so as to be reciprocally movable in the nozzle chamber, opening and closing between the nozzle chamber and the nozzle hole by one end portion, and interrupting the injection of the high-pressure fuel from the nozzle hole, A cylindrical cylinder (40) provided to be axially relatively movable with respect to the nozzle needle on the radially inner side of the end portion of the nozzle body on the side opposite to the nozzle hole; An orifice plate body (51) provided on the side of the nozzle body opposite to the nozzle hole, forming a pressure control chamber (500) between the inside of the cylinder and the other end of the nozzle needle, and an in-orifice passage (502) that opens on the surface of the orifice plate body on the pressure control chamber side and can supply the high-pressure fuel to the pressure control chamber. And an orifice plate (50); A floating plate (60) that reciprocates inside the end portion of the cylinder on the orifice plate side and allows or blocks communication between the in-orifice passage and the pressure control chamber by moving away from or contacting the orifice plate body. The cylinder has an annular groove (42) that is recessed radially outward from the inner peripheral wall of the end portion on the orifice plate side and forms an annular space (420), which is an annular space, between the outer peripheral wall of the floating plate, and a guide portion (43) that can guide the reciprocating movement of the floating plate by sliding on the outer peripheral wall of the floating plate on the side opposite to the orifice plate of the groove. A fuel injection device. "Disclosure 2" The fuel injection device according to Disclosure 1, wherein the groove has a straight portion (421) that forms an inner peripheral wall parallel to the inner peripheral wall of the guide portion. "Disclosure 3" The groove has a connecting portion (44) that connects the straight portion and the guide portion. In a cross-section by a plane including the axis of the cylinder, the connecting portion is formed to be linear or curved. The fuel injection device according to Disclosure 2. "Disclosure 4" The fuel injection device according to any one of Disclosures 1 to 3, wherein the cylinder has a longitudinal groove (45) that is recessed radially outward from the inner peripheral wall and extends along the axial direction of the cylinder. "Disclosure 5" The fuel injection device according to any one of Disclosures 1 to 4, wherein an area of one of two cross-sections formed when the annular space is cut by a plane including the axis of the cylinder is 1 / 2 or more of a minimum flow path cross-sectional area of the in-orifice passage. "Disclosure 6" A spring (36) provided on a side of the floating plate opposite to the orifice plate and biasing the floating plate toward the orifice plate side, The fuel injection device according to any one of Disclosures 1 to 5, wherein, in a state where the spring is compressed only by the weight of the floating plate, an end portion of the outermost diameter portion of the floating plate on the spring side is located on a side opposite to the groove with respect to an end portion of the guide portion on the groove side. "Disclosure 7" The fuel injection device according to any one of Disclosures 1 to 6, wherein the orifice plate has an annular groove (55) that is an annular groove recessed from a portion of the end surface of the orifice plate body on the cylinder side facing the annular space toward the side opposite to the cylinder.

[0095] Thus, the present disclosure is not limited to the above-described embodiments, and can be implemented in various forms without departing from the gist thereof.

Explanation of Reference Numerals

[0096] 1 Fuel injection device, 2 Accumulation pipe, 20 Nozzle body, 23 Injection hole, 30 Nozzle needle, 40 Cylinder, 42 Groove, 43 Guide portion, 50 Orifice plate, 51 Orifice plate body, 60 Floating plate, 200 Nozzle chamber, 420 Annular space, 500 Pressure control chamber, 502 In-orifice passage

Claims

1. A fuel injection device that injects high-pressure fuel accumulated in a pressure accumulation pipe (2) into an internal combustion engine, a nozzle body (20) having a nozzle chamber (200) into which the high-pressure fuel flows, and a nozzle hole (23) that communicates with the nozzle chamber and injects the high-pressure fuel, a nozzle needle (30) that is provided so as to be reciprocally movable within the nozzle chamber, opens and closes the space between the nozzle chamber and the nozzle hole with one end, and interrupts the injection of the high-pressure fuel from the nozzle hole, a cylindrical cylinder (40) that is provided so as to be axially relatively movable with respect to the nozzle needle on the radially inner side of the end of the nozzle body on the side opposite to the nozzle hole, an orifice plate body (51) that is provided on the side of the nozzle body opposite to the nozzle hole and forms a pressure control chamber (500) between the inside of the cylinder and the other end of the nozzle needle, and an orifice plate (50) having an in-orifice passage (502) that opens on the surface of the orifice plate body on the pressure control chamber side and can supply the high-pressure fuel to the pressure control chamber, a floating plate (60) that reciprocates inside the end of the cylinder on the orifice plate side and allows or blocks communication between the in-orifice passage and the pressure control chamber by separating from or contacting the orifice plate body, and is provided with, The cylinder has an annular groove (42) that is recessed radially outward from the inner peripheral wall of the end on the orifice plate side and forms an annular space (420) that is an annular space between the outer peripheral wall of the floating plate, and a guide portion (43) that can guide the reciprocating movement of the floating plate by sliding on the outer peripheral wall of the floating plate on the side opposite to the orifice plate of the groove. Fuel injection device.

2. The fuel injection device according to claim 1, wherein the groove has a straight portion (421) that forms an inner peripheral wall parallel to the inner peripheral wall of the guide portion.

3. The groove has a connecting portion (44) that connects the straight portion and the guide portion, The fuel injection device according to claim 2, wherein in a cross section by a plane including the axis of the cylinder, the connecting portion is formed to be linear or curved.

4. The fuel injection device according to any one of claims 1 to 3, wherein the cylinder has a longitudinal groove (45) that extends along the axial direction of the cylinder while being recessed radially outward from the inner peripheral wall.

5. The fuel injection device according to any one of claims 1 to 3, wherein an area (S1) of one of two cross-sections formed when the annular space is cut by a plane including the axis of the cylinder is 1 / 2 or more of a minimum flow path cross-sectional area (S2) of the in-orifice passage.

6. A spring (36) is provided on a side of the floating plate opposite to the orifice plate and biases the floating plate toward the orifice plate side. The fuel injection device according to any one of claims 1 to 3, wherein, in a state where the spring is compressed only by the weight of the floating plate, an end portion of the outermost diameter portion of the floating plate on the spring side is located on a side opposite to the groove with respect to an end portion of the guide portion on the groove side.

7. The fuel injection device according to any one of claims 1 to 3, wherein the orifice plate has an annular groove (55) that is an annular groove recessed from a portion of an end face of the orifice plate body on the cylinder side facing the annular space toward a side opposite to the cylinder.

Images