WO2016076007A1 - Fuel injection valve - Google Patents

Fuel injection valve Download PDF

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Publication number
WO2016076007A1
WO2016076007A1 PCT/JP2015/075858 JP2015075858W WO2016076007A1 WO 2016076007 A1 WO2016076007 A1 WO 2016076007A1 JP 2015075858 W JP2015075858 W JP 2015075858W WO 2016076007 A1 WO2016076007 A1 WO 2016076007A1
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WO
WIPO (PCT)
Prior art keywords
fuel injection
fuel
curvature
injection valve
convex
Prior art date
Application number
PCT/JP2015/075858
Other languages
French (fr)
Japanese (ja)
Inventor
石井　英二
一樹 吉村
岡本　良雄
小林　信章
Original Assignee
日立オートモティブシステムズ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 日立オートモティブシステムズ株式会社 filed Critical 日立オートモティブシステムズ株式会社
Priority to CN201580047012.2A priority Critical patent/CN106605060B/en
Publication of WO2016076007A1 publication Critical patent/WO2016076007A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
    • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/18—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for

Definitions

  • the present invention relates to a fuel injection valve used in an internal combustion engine such as a gasoline engine, wherein the fuel is prevented from leaking when the valve comes into contact with the valve seat, and injection is performed when the valve is separated from the valve seat.
  • an internal combustion engine such as a gasoline engine
  • Patent Document 1 JP-A 2006-177244 (Patent Document 1) as background art in this technical field.
  • Patent Document 1 discloses an invention that improves the atomization performance of the fuel injected by the fuel injection valve, realizes the improvement of the atomization performance with a simple configuration, and reduces the manufacturing cost.
  • the fuel injection valve disclosed in this publication includes a valve body that can be opened and closed for injecting and stopping fuel injection, a nozzle plate having a valve seat that is in contact with and away from the valve body, and a plurality of fixed and fixed to the nozzle plate.
  • a fuel injection valve having an orifice plate having a fuel injection hole, wherein the nozzle plate has a diameter reduced from the valve seat and extends downstream from the fuel introduction hole in the valve diameter direction to form a fuel injection hole.
  • the orifice plate is composed of a plurality of concave fuel passages connected to each other and a convex portion having a curved surface separating the concave fuel passages, and the orifice plate forms a concave bottom surface portion having a plurality of fuel injection holes arranged in the valve diameter direction.
  • the bottom surface of the shape has a curved surface shape equivalent to the curved surface of the convex portion of the nozzle plate, and the fuel injection from the fuel injection hole forms a horseshoe-shaped jet, thereby obtaining the effect of promoting atomization.
  • the object of the present invention is to provide a fuel injection valve capable of simplifying the processing of the fuel injection portion and capable of forming a fuel spray with good atomization characteristics, thereby further increasing the manufacturing cost. It is to contribute to the reduction of fuel consumption of automobile engines and the purification of exhaust gas as well as the reduction.
  • a fuel injection valve includes a seat member having a valve seat, a valve body that is seated and seated on the seat member, and the valve body of the seat member is seated and seated.
  • the peripheral portion located radially outward with respect to the central portion of the convex portion is configured so that the convex portion of the fuel diffusion chamber is closer to a virtual plane extending the central portion outward in the radial direction.
  • the fuel injection hole located on the facing ceiling surface side Inlet opening face is opened in the peripheral portion.
  • the position in the up / down / left / right direction or the up / down / left / right direction is defined with reference to the plane of FIG.
  • the position in the up / down / left / right direction or the up / down / left / right direction does not mean the position in the up / down / left / right direction or the up / down / left / right direction in the mounted state of the fuel injection valve.
  • FIG. 1 is a sectional view showing an embodiment of a fuel injection valve according to the present invention.
  • the whole structure of the fuel injection valve shown in FIG. 1 is a structure common also in another Example.
  • a fuel injection valve 1 supplies fuel to an internal combustion engine used as, for example, an automobile engine.
  • the fuel injection valve 1 is a multi-hole injector that is normally closed.
  • the casing 2 is formed in a cylindrical shape having an integrated structure with a step having an elongated and thin-walled portion by pressing or cutting.
  • the material is a ferritic stainless steel material plus a flexible material such as titanium, and has magnetic properties.
  • a fuel supply port 2a is provided at one end of the casing 2, and a nozzle plate 6 (see FIG. 3) having a plurality of fuel injection holes 7 is provided at the other end.
  • the nozzle plate 6 is fixed to the nozzle body 5 provided at the other end of the casing 2 by welding or the like.
  • a plurality of fuel injection holes 7 are formed in the nozzle plate 6 (see FIG. 3).
  • the plurality of fuel injection holes 7 are not distinguished and will be referred to as fuel injection holes 7.
  • a fixed core 15 that is disposed inside the electromagnetic coil 14 after being inserted into the casing 2
  • an anchor (movable core) 4 that is disposed to face an end surface on the front end side of the fixed core 15,
  • a valve body 3 having a hollow portion 3a provided integrally with the anchor 4 and extending in the axial direction, a nozzle body 5 fixed to the casing 2 on the distal end side of the valve body 3, and a distal end side surface of the nozzle body 5
  • An arranged nozzle plate 6 is provided.
  • the anchor 4 is attached so as to be opposed to the end face on the distal end side of the fixed core 15 with a gap and to be movable in the axial direction.
  • the anchor 4 is manufactured by injection molding metal powder made of a magnetic material by a method such as MIM (Metal Injection Molding).
  • the nozzle body 5 is a member formed with a valve seat surface 5b (see FIG. 2) on which the tip of the valve body 3 is separated.
  • the nozzle plate 6 is provided with a plurality of fuel injection holes formed penetrating in the thickness direction.
  • the nozzle plate 6 is joined to the surface in contact with the nozzle body 5 by welding, and the nozzle body 5 is joined to the casing 2 by welding.
  • a spring 12 as an elastic member is disposed inside the fixed core 15.
  • One end of the spring 12 is in contact with the inside of the anchor 4 and gives a force (urging force in the valve closing direction) to press the tip of the spring 12 against the nozzle body 5.
  • the other end of the spring 12 is in contact with the spring adjuster 13, and the spring adjuster 13 adjusts the pressing force of the spring 12 against the valve body 3.
  • a filter 20 is disposed at the fuel supply port 2a to remove foreign matters contained in the fuel.
  • an O-ring 21 for sealing the supplied fuel is attached to the outer periphery of the fuel supply port 2a.
  • the resin cover 22 is provided so as to cover the upper side of the casing 2 and the yoke 16 by means such as a resin mold.
  • the resin cover 22 is integrally formed with a connector 23 for supplying power to the electromagnetic coil 14.
  • the protector 24 is a cylindrical member made of, for example, a resin material provided at the tip end (lower end side) of the fuel injection valve 1, and has a flange 24 a that protrudes radially outward from the casing 2. ing.
  • the O-ring 25 is attached to the outer periphery on the front end side of the casing 2.
  • the O-ring 25 is fitted between the flange portion 24a of the protector 24 and a step portion 16c formed between the large-diameter portion 16a and the small-diameter portion 16b of the yoke 16, and is attached to the fuel injection valve. .
  • the O-ring 25 is disposed between the yoke 16 and the protector 24 so as not to be pulled out. For example, when the front end side of the casing 2 is attached to an attachment portion (not shown) provided on the intake pipe of the internal combustion engine, It seals the gap between.
  • a magnetic flux flows through a magnetic circuit formed by the yoke 16 made of a magnetic material, the fixed core 15, and the anchor 4.
  • a magnetic attractive force acts between the upper end surface 4 a of the anchor 4 and the lower end surface 15 a of the fixed core 15. That is, the electromagnetic force (magnetic attractive force) of the electromagnetic coil 14 acts between the opposing surfaces of the anchor 4 and the fixed core 15 facing each other.
  • the valve body 3 moves upward (in the valve opening direction) until the upper end surface 4 a of the anchor 4 contacts the lower end surface 15 a of the core 15 by the electromagnetic force of the electromagnetic coil 14.
  • valve open state When the valve body 3 moves to the core 15 side, the fuel passage between the valve body 3 and the valve seat surface 5b of the nozzle body 5 is opened (valve open state). In the valve open state, the fuel in the casing 2 flows down the valve body 3, the nozzle body 5, and the seat portions 3c, 5c, and is then injected from the fuel injection hole 7 (see FIG. 2).
  • the fuel injection amount is controlled by injection pulses applied intermittently to the electromagnetic coil 14.
  • the fuel injection amount is controlled by moving the valve body 3 in the axial direction according to the injection pulse and adjusting the switching timing between the valve open state and the valve close state according to the pulse width of the injection pulse. ing.
  • FIG. 2 is an enlarged cross-sectional view of the vicinity of the tip of the valve body of the fuel injection valve according to the first embodiment of the present invention.
  • the valve body 3 uses a ball valve.
  • balls for example, JIS standard ball bearing steel balls are used. This ball has a high roundness and has a mirror finish, and is suitable for enhancing sheet properties, and suitable for cost reduction by mass production. .
  • a ball having a diameter of about 3 to 4 mm is used. This is to reduce the weight because it functions as a movable valve.
  • the angle of the inclined surface including the position of the sheet 5c in close contact with the valve body 3 is about 90 ° (80 ° to 100 °).
  • This inclination angle is an optimum angle for polishing the vicinity of the position of the seat 5c and increasing the roundness (the grinding machine can be used in the best condition), and the sheet property with the valve body 3 can be maintained extremely high. Is.
  • the nozzle body 5 having the inclined surface including the position of the sheet 5c is increased in hardness by quenching, and unnecessary magnetism is removed by demagnetization treatment. With such a valve body configuration, it is possible to control the injection amount without fuel leakage. Moreover, the valve body structure excellent in cost performance can be provided.
  • the nozzle plate 6 is extruded by punching in a manufacturing process for forming a convex surface (down convex shape portion) 6A in order to form a downward convex shape.
  • the downward convex portion 6A is formed in a convex shape toward the outside of the fuel injection valve, and constitutes a fuel diffusion chamber 43 in which the fuel diffuses radially outward from the center side (center axis 100 side). To do.
  • the bottom surface (lower surface) of the fuel diffusion chamber 43 is configured by the nozzle plate 6, and the ceiling surface (upper surface) of the fuel diffusion chamber 43 is configured by the lower end surface of the nozzle body 5.
  • valve body 3 When the fuel injection valve is in the closed state, the valve body 3 keeps the fuel seal by contacting the valve seat surface 5b formed of a conical surface provided on the seat member 5a joined to the nozzle body 5 by welding or the like. It is like that. At this time, the contact portion (seat portion) 5c on the valve body 3 side is formed of a spherical surface, and the contact between the conical surface of the valve seat surface and the spherical surface is in a substantially line contact state.
  • the valve body 3 rises and a gap is formed between the valve body 3 and the seat member 5a, the fuel flows out of the gap and collides with the upper surface of the nozzle plate 6 from the direction of the arrow 17 at the opening 5d of the seat member 5a.
  • the gas flows from the center of the nozzle plate 6 along the surface of the nozzle plate 6 as indicated by an arrow 18.
  • the fuel forms a liquid film 9 after passing through the fuel injection hole 7.
  • the liquid film 9 is split into droplets 10 due to instability due to surface tension waves and shearing force with air, and fuel atomization is achieved.
  • the radius of the opening 5d is smaller than the radius of the opening position of the fuel injection hole 7, and the fuel that has flowed from the opening 5d into the downward convex portion 6A flows outward in the radial direction, and then the fuel It flows into the injection hole 7.
  • the relationship between the opening 5d and the opening position of the fuel injection hole 7 is the same in other embodiments described later.
  • FIG. 3 is a view of the nozzle plate of the fuel injection valve according to the first embodiment of the present invention as viewed from the valve body side.
  • the direction of each fuel injection hole 7 is indicated by an arrow 11 when the target direction of the fuel spray is set to two directions.
  • the direction of the injection hole is generally referred to as direction 11.
  • Each fuel injection hole 7 is directed in the left-right direction on the paper surface of FIG. That is, the group of the plurality of fuel injection holes 7 arranged on the left side in FIG. 3 has the fuel spray target direction set to the left, and the group of the plurality of fuel injection holes 7 arranged on the right side.
  • the fuel spray target direction is set to the right.
  • FIG. 3 shows an example applied to two target directions, the target direction is not limited to two directions such as a radial direction.
  • FIG. 4 is an explanatory diagram of a fuel atomization mechanism in the present invention. 4 shows an enlarged view of the right half near the nozzle plate 6 of FIG.
  • the fuel flow 17 at the opening 5d of the fuel passage portion collides with the upper surface of the nozzle plate 6, and a flow field having a high speed region is formed on the upper surface side of the nozzle plate 6 as in the velocity distribution 8.
  • the curvature of the curved surface shape is increased as the distance from the center of the nozzle plate 6 increases, and the effect of pressing the flow toward the upper surface of the nozzle plate 6 is increased. Is even faster.
  • the flow on the upper surface of the nozzle plate 6 has a property of flowing in the tangential direction of the curved surface, and the flow direction changes upward in FIG. 4 as the curvature increases.
  • the effect of pressing the flow toward the upper surface of the nozzle plate 6 is obtained by the amount of the flow changing direction.
  • FIG. 5 is an enlarged cross-sectional view of the vicinity of the tip of the valve body of the fuel injection valve in the conventional invention.
  • the curvature of the curved surface shape is increased as the distance from the center of the nozzle plate 6 increases, so that the tangential direction (fuel flow direction) of the curved surface of the nozzle plate 6 is upstream of the fuel injection hole 7.
  • the direction change in the central axis direction (fuel injection direction) of the fuel injection hole 7 becomes large.
  • the flow velocity component in the direction perpendicular to the injection direction can be increased in the injection hole, and the fuel When exiting the injection hole, the diffusion effect of the fuel becomes stronger and the atomization of the fuel is further promoted.
  • FIG. 6 is a diagram for explaining the difference in fuel atomization mechanism between the present embodiment and the prior art. 6 shows an enlarged view of the right half near the nozzle plate 6 of FIG.
  • the range indicated by reference numeral 40 of the nozzle plate 6 is a flat surface.
  • the plane is a case where the curvature is 0.
  • the downward convex portion 6A is configured to increase from the curvature 0 toward the radially outward direction from the center portion.
  • the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed extends radially inward from the inlet opening surface of the fuel injection hole 7. It is located on the radius direction inner side of the virtual surface 42 or on the curvature center O side of the virtual surface 42 (see FIG. 4). That is, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is located closer to the ceiling surface (upper surface) 5 e side of the fuel diffusion chamber 43 than the virtual surface 42.
  • the ceiling surface 5e is a wall surface of the fuel diffusion chamber 43 that faces the nozzle plate 6 constituting the convex portion 6A.
  • the radially inner portion that is, the center portion of the downward convex portion 6A is a flat surface, so that the center of curvature is located at an infinite distance upward on the paper surface of FIG.
  • the inlet opening surface of the fuel injection hole 7 is located radially outward with respect to the flat central portion 40 and opens to the peripheral portion 41 where the curvature increases as the distance from the center increases.
  • the center of curvature of the plane is located at an infinite distance downward from the nozzle plate 6 on the paper surface of FIG.
  • the downward convex portion 6A is a portion that has a center of curvature on the upper side with respect to the nozzle plate 6 and is convex downward. That is, the center of curvature of the downward convex portion 6A is originally disposed above the nozzle plate 6, and the plane is a special example of such downward convex portion 6A. Therefore, it is assumed that the center of curvature of the plane formed in the downward convex portion 6A is arranged on the upper side with respect to the nozzle plate 6 on the paper surface of FIG.
  • the curvature of the peripheral portion 41 may be set to a constant value greater than zero.
  • the curvature of the central portion 40 may be set to a value smaller than the curvature set to the peripheral portion 41 and larger than 0.
  • a fuel injection valve according to the second embodiment of the present invention will be described below with reference to FIGS. Those assigned the same numbers as those used in the description of the first embodiment have the same or equivalent functions as those of the first embodiment, and the description thereof will be omitted.
  • FIG. 7 is an enlarged cross-sectional view of the vicinity of the tip of the valve body of the fuel injection valve according to the second embodiment of the present invention.
  • the second embodiment shown in FIG. 7 is characterized in that the curved surface shape (downward convex portion) 6A of the nozzle plate 6 is formed with two kinds of curvatures as compared to FIG. 2 of the first embodiment. . That is, the downward convex portion 6 ⁇ / b> A has a curvature set to the first curvature at the central portion 70 of the nozzle plate 6, and has a curvature at the peripheral portion 71 located radially outward with respect to the central portion 70 of the nozzle plate 6. The second curvature is set.
  • the inlet opening surface of the fuel injection hole 7 opens to the peripheral portion 71 formed with the second curvature.
  • the second curvature is a larger value than the first curvature.
  • the first curvature may be zero. That is, the central portion 70 of the nozzle plate 6 may be configured as a flat surface.
  • the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is more than the virtual surface 72 that extends inward in the radial direction from the inlet opening surface of the fuel injection hole 7. , Located in the radially inner portion or the center of curvature of the virtual plane 72. That is, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is located closer to the ceiling surface (upper surface) 5 e side of the fuel diffusion chamber 43 than the virtual surface 72.
  • the change in the curvature of the nozzle plate 6 can be constituted by a combination of a plane having a different inclination and an inclined surface (tapered surface or conical surface). is there.
  • An example is shown in FIG. FIG. 8 is an example in which the change in the curvature of the nozzle plate is constituted by two planes in the fuel injection valve according to the second embodiment of the present invention.
  • the peripheral portion 81 located outward in the radial direction is configured by an inclined surface (tapered surface or conical surface) inclined with respect to the plane of the central portion 80.
  • the tapered surface of the peripheral portion 81 is inclined so that the inner peripheral side is positioned below the outer peripheral side.
  • the central portion 80 corresponds to the central portion 40 in FIG. 7, and the peripheral portion 81 corresponds to the peripheral portion 41 in FIG.
  • the inlet opening surface of the fuel injection hole 7 opens to the tapered surface of the peripheral portion 81.
  • FIG. 9 is an enlarged cross-sectional view of the vicinity of the tip of the valve body of the fuel injection valve according to the third embodiment of the present invention.
  • Those assigned the same numbers as those used in the description of the first embodiment have the same or equivalent functions as those in the first embodiment, and will not be described.
  • the opening 5 d provided in the downstream direction of the sheet member 5 a is inside the fuel injection hole 7 when viewed from the center of the nozzle plate 6, and the center side (center part) 90 of the nozzle plate 6.
  • An inclined surface (tapered surface or conical surface) is provided on the outer peripheral side of the downwardly convex curved surface 6C, that is, the peripheral portion 91 radially outward of the central portion 90, and the inlet opening of the fuel injection hole 7 is provided on this inclined surface.
  • a surface is provided.
  • the tapered surface formed in the peripheral portion 91 is located closer to the center of curvature of the curved surface 6C than the virtual surface 92 obtained by extending the downwardly convex curved surface 6C.
  • the tapered surface 91 may be configured to have a curvature larger than that of the curved surface 6 ⁇ / b> C, and the curvature may change from the center side (inner peripheral side) toward the outer peripheral side. Or you may comprise the taper surface 91 so that it may have a curvature larger than the curvature of the curved surface 6C, and may become a fixed curvature toward the outer peripheral side from a center side (inner peripheral side).
  • the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is located on the imaginary surface 92 and on the curvature center O side of the curved surface 6C protruding downward from the imaginary surface 92. . That is, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is located closer to the ceiling surface (upper surface) 5 e side of the fuel diffusion chamber 43 than the virtual surface 92.
  • the basic operation of the fuel injection valve is the same as in the first and second embodiments. Further, the fuel spray target direction is the same as in the first and second embodiments.
  • the space on the upper surface of the nozzle plate 6 can be made smaller than that in the example of FIG. 2, and as a result, the fuel injection characteristics under negative pressure are also improved.
  • the inlet opening surface of the fuel injection hole 7 may be provided on the curved surface 6C that protrudes downward. Also in this case, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is higher than the imaginary surface 93 (see FIG. 9) of the upwardly curved surface 6B. ) 5e side.
  • the direction change in the tangential direction (fuel flow direction) of the curved surface of the nozzle plate 6 and the central axis direction (fuel injection direction) of the fuel injection hole 7 becomes large.
  • the flow velocity component in the direction perpendicular to the injection direction can be increased in the injection hole 7.
  • the diffusion effect of a fuel becomes strong and atomization of a fuel is further accelerated
  • the curvature of the downwardly convex curved surface 6C is increased outward in the radial direction like the peripheral portion 41 of the first embodiment. You may let them.
  • the downwardly convex curved surface 6C has a shape in which the curvature on the center side (inner circumference side) has the first curvature, and the outer side in the radial direction (outer circumference side) with respect to the center side is more than the first curvature. You may make it the shape which has a big 2nd curvature.
  • the first curvature and the second curvature are each set to a constant value.
  • the fuel injection valve according to the present invention has a simple structure in which the nozzle plate has a curved surface shape convex downward, and the curvature of the curved surface shape increases as the distance from the center of the nozzle plate increases. With this nozzle plate structure, it is possible to increase the flow velocity component in the direction perpendicular to the injection direction in the injection hole, and when the fuel exits the injection hole, the fuel diffusion effect becomes stronger and the fuel atomizes. Is promoted.
  • this invention is not limited to each above-mentioned Example, Various modifications are included.
  • the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations.
  • a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.
  • SYMBOLS 1 Fuel injection valve, 2 ... Casing, 2a ... Fuel supply port, 3 ... Valve body, 3c ... Seat part, 4 ... Anchor, 5 ... Nozzle body, 5a ... Seat member, 5b ... Valve seat surface, 5c ... Seat part 5d: Opening portion, 5e: Lower end surface of the nozzle body (ceiling surface of the fuel diffusion chamber), 6 ... Nozzle plate, 6A ... Lower convex shape portion, 6B ... Upper convex curved surface, 6C ... Lower convex curved surface, 6a ... the upper surface of the nozzle plate of the present invention, 6aa ...
  • Peripheral part of the downward convex part, 72 ... Extending the central part 70 Virtual surface, 80 ... Center portion of convex shape portion, 81 ... peripheral portion of lower convex shape portion, 90 ... central portion of lower convex shape portion, 91 ... peripheral portion of lower convex shape portion, 92 ... virtual surface obtained by extending convex curved surface 6C downward 93 ... A virtual surface obtained by extending the convex curved surface 6B upward.

Abstract

The present invention achieves atomization of fuel spray from a fuel injection valve used for an internal combustion engine. The fuel injection valve is provided with a seat member 5a, a valve body 3, an opening 5d formed downstream of a seat section 5c of the seat member 5a, and a nozzle plate 6 disposed on the downstream side of the opening 5d. The nozzle plate 6 has a convex section 6A, formed in an outward convex shape, and fuel injection holes 7, formed radially outward of the opening 5d, so that a fuel diffusion chamber 43 in which fuel flows while diffusing outward in the radial direction is formed on the inner side of the convex section 6A. A peripheral section 41 located on the radially outer side of a center section 40 of the convex section 6A is positioned on the ceiling surface 5e side of the fuel diffusion chamber 43, which faces the convex section 6A, relative to a virtual plane 42 that is a radial outward extension of the center section 40, and inlet opening surfaces of the fuel injection holes 7 are opened in the peripheral section 41.

Description

燃料噴射弁Fuel injection valve
　本発明は、ガソリンエンジン等の内燃機関に用いられる燃料噴射弁であって、弁が弁座と当接することで燃料の漏洩を防止し、弁が弁座から離れることによって噴射を行なう燃料噴射弁に関する。 The present invention relates to a fuel injection valve used in an internal combustion engine such as a gasoline engine, wherein the fuel is prevented from leaking when the valve comes into contact with the valve seat, and injection is performed when the valve is separated from the valve seat. About.
　本技術分野の背景技術として、特開２００６－１７７２４４号公報（特許文献１）がある。この公報には、燃料噴射弁による噴射燃料の微粒化性能を向上させるとともに、微粒化性能の向上を簡単な構成で実現し、且つ製造コストを低減する発明が開示されている。 There is JP-A 2006-177244 (Patent Document 1) as background art in this technical field. This publication discloses an invention that improves the atomization performance of the fuel injected by the fuel injection valve, realizes the improvement of the atomization performance with a simple configuration, and reduces the manufacturing cost.
　この公報に開示された燃料噴射弁は、燃料の噴射と噴射停止を行うための開閉可能な弁体と、弁体と離接する弁座を有するノズルプレートと、ノズルプレートに固設されて複数の燃料噴射孔を有するオリフィスプレートと、を備えた燃料噴射弁であって、ノズルプレートは弁座より縮径された燃料導入孔と燃料導入孔の下流側で弁径方向に延びて燃料噴射孔に繋がる複数の凹形状燃料通路と凹形状燃料通路を隔てる曲面をもつ凸形状部とから構成され、オリフィスプレートは弁径方向に複数の燃料噴射孔の配置された凹形状底面部を形成し、凹形状底面部はノズルプレートの凸形状部の曲面と同等の曲面形状を有し、燃料噴射孔からの燃料噴射は馬蹄型状の噴流を形成することにより、微粒化を促進する効果が得られる。 The fuel injection valve disclosed in this publication includes a valve body that can be opened and closed for injecting and stopping fuel injection, a nozzle plate having a valve seat that is in contact with and away from the valve body, and a plurality of fixed and fixed to the nozzle plate. A fuel injection valve having an orifice plate having a fuel injection hole, wherein the nozzle plate has a diameter reduced from the valve seat and extends downstream from the fuel introduction hole in the valve diameter direction to form a fuel injection hole. The orifice plate is composed of a plurality of concave fuel passages connected to each other and a convex portion having a curved surface separating the concave fuel passages, and the orifice plate forms a concave bottom surface portion having a plurality of fuel injection holes arranged in the valve diameter direction. The bottom surface of the shape has a curved surface shape equivalent to the curved surface of the convex portion of the nozzle plate, and the fuel injection from the fuel injection hole forms a horseshoe-shaped jet, thereby obtaining the effect of promoting atomization.
特開２００６－１７７２４４号公報JP 2006-177244 A
　近年、自動車エンジンの低燃費化及び排出ガスの清浄化が求められており、このためには自動車エンジンへ供給される燃料噴霧の微粒化が必要である。特許文献１の燃料噴射弁では、燃料噴射孔から噴射される噴流を馬蹄型状にすることにより微粒化を図っている。
しかしこの燃料噴射弁では、ノズルプレートに形成された複数の凹形状燃料通路と曲面をもつ凸形状部とからなる燃料噴射部の加工を簡素化して、更なる製造コストの低減が望まれる。 In recent years, there has been a demand for reduction in fuel consumption of automobile engines and purification of exhaust gas. To this end, atomization of fuel spray supplied to the automobile engine is necessary. In the fuel injection valve of Patent Document 1, atomization is achieved by making the jet injected from the fuel injection hole into a horseshoe shape.
However, in this fuel injection valve, it is desired to further reduce the manufacturing cost by simplifying the processing of the fuel injection portion comprising a plurality of concave fuel passages formed in the nozzle plate and the convex portion having a curved surface.
　本発明の目的は、上記課題に対し、燃料噴射部の加工を簡素化することができ、かつ微粒化特性の良い燃料噴霧を形成可能な燃料噴射弁を提供することで、更なる製造コストの低減とともに、自動車エンジンの低燃費化及び排出ガスの清浄化に寄与することにある。 The object of the present invention is to provide a fuel injection valve capable of simplifying the processing of the fuel injection portion and capable of forming a fuel spray with good atomization characteristics, thereby further increasing the manufacturing cost. It is to contribute to the reduction of fuel consumption of automobile engines and the purification of exhaust gas as well as the reduction.
　上記目的を達成するために、本発明の燃料噴射弁は、弁座を有するシート部材と、前記シート部材に離座及び着座する弁体と、前記シート部材の前記弁体が離座及び着座するシート部よりも下流側に形成された開口部と、前記開口部の下流側に配置されたノズルプレートとを備え、前記ノズルプレートは外方に向けて凸状となる凸形状部を有すると共に、前記開口部よりも半径方向外方に形成された燃料噴射孔を有し、前記凸形状部の内側に燃料が半径方向外方に向かって拡散するように流れる燃料拡散室が形成された燃料噴射弁において、前記凸形状部の中心部に対して半径方向外方に位置する周辺部が、前記中心部を半径方向外方に延長した仮想面よりも、前記燃料拡散室の前記凸形状部と対向する天井面側に位置し、前記燃料噴射孔の入口開口面が前記周辺部に開口する。 In order to achieve the above object, a fuel injection valve according to the present invention includes a seat member having a valve seat, a valve body that is seated and seated on the seat member, and the valve body of the seat member is seated and seated. An opening formed on the downstream side of the seat portion, and a nozzle plate disposed on the downstream side of the opening, the nozzle plate having a convex portion that is convex outward, A fuel injection hole having a fuel injection hole formed radially outward from the opening, and having a fuel diffusion chamber that flows so that fuel diffuses outward in the radial direction inside the convex portion In the valve, the peripheral portion located radially outward with respect to the central portion of the convex portion is configured so that the convex portion of the fuel diffusion chamber is closer to a virtual plane extending the central portion outward in the radial direction. The fuel injection hole located on the facing ceiling surface side Inlet opening face is opened in the peripheral portion.
　本発明によれば、燃料噴射部の加工を簡素化することにより製造コストの低減がはかれ、かつ微粒化特性の良い燃料噴霧を形成可能な燃料噴射弁を提供することが可能である。 According to the present invention, it is possible to provide a fuel injection valve that can reduce the manufacturing cost by simplifying the processing of the fuel injection section and can form fuel spray with good atomization characteristics.
　上記した以外の課題、構成及び効果は、以下の実施形態の説明により明らかにされる。 Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.
本発明に係る燃料噴射弁の一実施例を示す断面図である。It is sectional drawing which shows one Example of the fuel injection valve which concerns on this invention. 本発明の第１実施例に係る燃料噴射弁の弁体先端の近傍を拡大した断面図である。It is sectional drawing to which the vicinity of the valve body front-end | tip of the fuel injection valve which concerns on 1st Example of this invention was expanded. 本発明の第１実施例に係る燃料噴射弁のノズルプレートを弁体側から見た図である。It is the figure which looked at the nozzle plate of the fuel injection valve which concerns on 1st Example of this invention from the valve body side. 本発明における、燃料の微粒化メカニズムの説明図である。It is explanatory drawing of the atomization mechanism of the fuel in this invention. 従来技術における、燃料噴射弁の弁体先端の近傍を拡大した断面図である。It is sectional drawing which expanded the vicinity of the valve body front-end | tip of a fuel injection valve in a prior art. 本発明と従来技術における、燃料の微粒化メカニズムの違いを説明した図である。It is a figure explaining the difference in the atomization mechanism of the fuel in this invention and a prior art. 本発明の第２実施例に係る燃料噴射弁の弁体先端の近傍を拡大した断面図である。It is sectional drawing to which the vicinity of the valve body front-end | tip of the fuel injection valve which concerns on 2nd Example of this invention was expanded. 本発明の第２実施例に係る燃料噴射弁におけるノズルプレートの曲率の変化を、２つの平面で構成した例である。It is the example which comprised the change of the curvature of the nozzle plate in the fuel injection valve which concerns on 2nd Example of this invention by two planes. 本発明の第３実施例に係る燃料噴射弁の弁体先端の近傍を拡大した断面図である。It is sectional drawing to which the vicinity of the valve body front-end | tip of the fuel injection valve which concerns on 3rd Example of this invention was expanded.
　以下、本発明の実施例を、図面を用いて説明する。なお、以下の説明において、上下左右方向或いは上下左右方向における位置は、図１の紙面を基準にして定義される。この上下左右方向或いは上下左右方向における位置は、燃料噴射弁の実装状態における上下左右方向或いは上下左右方向における位置を意味するものではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the position in the up / down / left / right direction or the up / down / left / right direction is defined with reference to the plane of FIG. The position in the up / down / left / right direction or the up / down / left / right direction does not mean the position in the up / down / left / right direction or the up / down / left / right direction in the mounted state of the fuel injection valve.
　本発明の第１実施例に係わる燃料噴射弁について、図１乃至図６を用いて以下説明する。 The fuel injection valve according to the first embodiment of the present invention will be described below with reference to FIGS.
　図１を用いて、燃料噴射弁の基本構造とその動作について説明する。図１は、本発明に係る燃料噴射弁の実施例を示す断面図である。なお、図１に示す燃料噴射弁の全体的な構成は、他の実施例においても共通する構成である。 The basic structure and operation of the fuel injection valve will be described with reference to FIG. FIG. 1 is a sectional view showing an embodiment of a fuel injection valve according to the present invention. In addition, the whole structure of the fuel injection valve shown in FIG. 1 is a structure common also in another Example.
　図１において、燃料噴射弁１は、例えば自動車のエンジンとして利用される内燃機関に燃料を供給するものである。燃料噴射弁１は、通常閉じているマルチホールインジェクタである。ケーシング２は、プレス加工や切削加工等により細長く薄肉部がある段差付の一体構造よりなる円筒状に形成される。素材はフェライト系ステンレス材料にチタンのような柔軟性のある材料を加えたもので、磁性特性を有している。ケーシング２の一端部には燃料供給口２ａが設けられており、他端部には複数の燃料噴射孔７を有するノズルプレート６（図３参照）が設けられている。ノズルプレート６はケーシング２の他端部に設けられたノズル体５に溶接等により固着されている。 In FIG. 1, a fuel injection valve 1 supplies fuel to an internal combustion engine used as, for example, an automobile engine. The fuel injection valve 1 is a multi-hole injector that is normally closed. The casing 2 is formed in a cylindrical shape having an integrated structure with a step having an elongated and thin-walled portion by pressing or cutting. The material is a ferritic stainless steel material plus a flexible material such as titanium, and has magnetic properties. A fuel supply port 2a is provided at one end of the casing 2, and a nozzle plate 6 (see FIG. 3) having a plurality of fuel injection holes 7 is provided at the other end. The nozzle plate 6 is fixed to the nozzle body 5 provided at the other end of the casing 2 by welding or the like.
　図１には示されていないが、ノズルプレート６には複数の燃料噴射孔７が形成されている（図３参照）。以後、複数の燃料噴射孔７を区別せず、燃料噴射孔７と呼ぶことにする。 Although not shown in FIG. 1, a plurality of fuel injection holes 7 are formed in the nozzle plate 6 (see FIG. 3). Hereinafter, the plurality of fuel injection holes 7 are not distinguished and will be referred to as fuel injection holes 7.
　図１のケーシング２の外側には、電磁コイル１４と電磁コイル１４を包囲する磁性材のヨーク１６が設けられている。一方内側には、ケーシング２内に挿入された後に電磁コイル１４の内側に配置される固定コア１５と、固定コア１５の先端側の端面に対向して配置されたアンカー（可動コア）４と、アンカー４に一体的に設けられ軸方向に延材する中空部３ａを有する弁体３と、弁体３の先端側においてケーシング２に固設されたノズル体５と、ノズル体５の先端側面に配設されたノズルプレート６とが設けられている。 1 is provided with an electromagnetic coil 14 and a magnetic material yoke 16 surrounding the electromagnetic coil 14. On the other hand, on the inside, a fixed core 15 that is disposed inside the electromagnetic coil 14 after being inserted into the casing 2, an anchor (movable core) 4 that is disposed to face an end surface on the front end side of the fixed core 15, A valve body 3 having a hollow portion 3a provided integrally with the anchor 4 and extending in the axial direction, a nozzle body 5 fixed to the casing 2 on the distal end side of the valve body 3, and a distal end side surface of the nozzle body 5 An arranged nozzle plate 6 is provided.
　アンカー４は、固定コア１５の先端側の端面との間に空隙をもって対向し、軸方向に動くことが可能なように取り付けられている。アンカー４は磁性材料からなる金属粉末をMIM（Metal Injection Molding）等の工法により射出成形して製造される。ノズル体５は弁体３の先端が離接する弁座面５ｂ（図２参照）が形成された部材である。 The anchor 4 is attached so as to be opposed to the end face on the distal end side of the fixed core 15 with a gap and to be movable in the axial direction. The anchor 4 is manufactured by injection molding metal powder made of a magnetic material by a method such as MIM (Metal Injection Molding). The nozzle body 5 is a member formed with a valve seat surface 5b (see FIG. 2) on which the tip of the valve body 3 is separated.
　このノズルプレート６には、厚み方向に貫通して形成された複数の燃料噴射孔が設けられている。ノズルプレート６はノズル体５と接する面を溶接により接合されており、ノズル体５はケーシング２と溶接により接合されている。 The nozzle plate 6 is provided with a plurality of fuel injection holes formed penetrating in the thickness direction. The nozzle plate 6 is joined to the surface in contact with the nozzle body 5 by welding, and the nozzle body 5 is joined to the casing 2 by welding.
　図１において、固定コア１５の内部には、弾性部材としてのスプリング１２が配設されている。スプリング１２は、その一端部がアンカー４の内側に当接しており、弁体３に対してその先端をノズル体５に押し付ける力（閉弁方向の付勢力）を与える。このスプリング１２の他端部はスプリングアジャスタ１３に当接しており、スプリングアジャスタ１３はスプリング１２による弁体３に対する押し付け力を調整する。また、燃料供給口２ａには、フィルタ２０が配設されており、燃料に含まれる異物を除去する。さらに燃料供給口２ａの外周には、供給される燃料をシールするためのＯリング２１が取り付けられている。 In FIG. 1, a spring 12 as an elastic member is disposed inside the fixed core 15. One end of the spring 12 is in contact with the inside of the anchor 4 and gives a force (urging force in the valve closing direction) to press the tip of the spring 12 against the nozzle body 5. The other end of the spring 12 is in contact with the spring adjuster 13, and the spring adjuster 13 adjusts the pressing force of the spring 12 against the valve body 3. Further, a filter 20 is disposed at the fuel supply port 2a to remove foreign matters contained in the fuel. Further, an O-ring 21 for sealing the supplied fuel is attached to the outer periphery of the fuel supply port 2a.
　樹脂カバー２２は、例えば樹脂モールド等の手段によりケーシング２及びヨーク１６の上部側を覆うように設けられたものである。また、樹脂カバー２２には、電磁コイル１４に電力を供給するためのコネクタ２３が一体的に構成されている。 The resin cover 22 is provided so as to cover the upper side of the casing 2 and the yoke 16 by means such as a resin mold. The resin cover 22 is integrally formed with a connector 23 for supplying power to the electromagnetic coil 14.
　プロテクタ２４は、燃料噴射弁１の先端部（下端側）に設けられた、例えば樹脂材料等よりなる筒状部材をなしていて、ケーシング２より径方向外向きに突出した鍔部２４ａを有している。また、Ｏリング２５はケーシング２の先端側外周に装着されている。Ｏリング２５は、プロテクタ２４の鍔部２４ａと、ヨーク１６の大径部１６ａと小径部１６ｂとの間に形成された段差部１６ｃとの間に嵌められて、燃料噴射弁に取り付けられている。
Ｏリング２５はヨーク１６とプロテクタ２４との間に抜き止め状態で配置され、例えばケーシング２の先端側を内燃機関の吸気管に設けられた取り付け部（図示しない）等に取り付けた場合に、これらの間をシールするものである。 The protector 24 is a cylindrical member made of, for example, a resin material provided at the tip end (lower end side) of the fuel injection valve 1, and has a flange 24 a that protrudes radially outward from the casing 2. ing. The O-ring 25 is attached to the outer periphery on the front end side of the casing 2. The O-ring 25 is fitted between the flange portion 24a of the protector 24 and a step portion 16c formed between the large-diameter portion 16a and the small-diameter portion 16b of the yoke 16, and is attached to the fuel injection valve. .
The O-ring 25 is disposed between the yoke 16 and the protector 24 so as not to be pulled out. For example, when the front end side of the casing 2 is attached to an attachment portion (not shown) provided on the intake pipe of the internal combustion engine, It seals the gap between.
　このように構成される燃料噴射弁１は、電磁コイル１４が非通電状態であるときはスプリング１２の押し付け力に起因して、弁体３の先端がノズル体５の弁座面５ｂ（図２参照）に密着する。このような状態では、弁体３とノズル体５との間に隙間が形成されず、燃料通路が閉じた状態（閉弁状態）であるため、燃料供給口２ａから流入した燃料はケーシング２内部に留まる。 In the fuel injection valve 1 configured as described above, when the electromagnetic coil 14 is in a non-energized state, due to the pressing force of the spring 12, the tip of the valve body 3 is the valve seat surface 5b of the nozzle body 5 (FIG. 2). See). In such a state, a gap is not formed between the valve body 3 and the nozzle body 5, and the fuel passage is closed (valve closed state). Therefore, the fuel flowing in from the fuel supply port 2a Stay on.
　電磁コイル１４に噴射パルスとしての電流を印加すると、磁性材よりなるヨーク１６と、固定コア１５と、アンカー４とで形成される磁気回路に磁束が流れる。磁気回路に磁束が流れると、アンカー４の上端面４ａと固定コア１５の下端面１５ａとの間に磁気吸引力が働く。すなわち、アンカー４と固定コア１５との相互に対向する対向面間に、電磁コイル１４の電磁力（磁気吸引力）が働く。弁体３は、電磁コイル１４の電磁力によって、アンカー４の上端面４ａがコア１５の下端面１５ａに接触するまで上方（開弁方向）に移動する。弁体３がコア１５側に移動すると、弁体３とノズル体５の弁座面５ｂとの間の燃料通路が開かれた状態（開弁状態）となる。開弁状態では、ケーシング２内の燃料は、弁体３とノズル体５とシート部３ｃ、５ｃを流下した後、燃料噴射孔７から噴射される（図２参照）。 When a current as an injection pulse is applied to the electromagnetic coil 14, a magnetic flux flows through a magnetic circuit formed by the yoke 16 made of a magnetic material, the fixed core 15, and the anchor 4. When magnetic flux flows through the magnetic circuit, a magnetic attractive force acts between the upper end surface 4 a of the anchor 4 and the lower end surface 15 a of the fixed core 15. That is, the electromagnetic force (magnetic attractive force) of the electromagnetic coil 14 acts between the opposing surfaces of the anchor 4 and the fixed core 15 facing each other. The valve body 3 moves upward (in the valve opening direction) until the upper end surface 4 a of the anchor 4 contacts the lower end surface 15 a of the core 15 by the electromagnetic force of the electromagnetic coil 14. When the valve body 3 moves to the core 15 side, the fuel passage between the valve body 3 and the valve seat surface 5b of the nozzle body 5 is opened (valve open state). In the valve open state, the fuel in the casing 2 flows down the valve body 3, the nozzle body 5, and the seat portions 3c, 5c, and is then injected from the fuel injection hole 7 (see FIG. 2).
　燃料噴射量の制御は、電磁コイル１４に間欠的に印加する噴射パルスによって行う。噴射パルスに応じて、弁体３を軸方向に移動させると共に、噴射パルスのパルス幅に応じて開弁状態と閉弁状態との切り替えのタイミングを調整することで、燃料噴射量の制御を行っている。 The fuel injection amount is controlled by injection pulses applied intermittently to the electromagnetic coil 14. The fuel injection amount is controlled by moving the valve body 3 in the axial direction according to the injection pulse and adjusting the switching timing between the valve open state and the valve close state according to the pulse width of the injection pulse. ing.
　次に、本発明に係わる主要部品について、図２を用いて、簡潔に説明する。図２は、本発明の第１実施例に係る燃料噴射弁の弁体先端の近傍を拡大した断面図である。 Next, main parts according to the present invention will be briefly described with reference to FIG. FIG. 2 is an enlarged cross-sectional view of the vicinity of the tip of the valve body of the fuel injection valve according to the first embodiment of the present invention.
　図２に示されるように、弁体３はボール弁を使用している。ボールには、例えば、JIS規格品の玉軸受用鋼球を用いている。このボールは、真円度が高く鏡面仕上げが施されており、シート性を高めるのに好適であること、また、大量生産による低コスト化に好適であること、等がその採用のポイントである。また、弁体３として構成する場合は、ボールの直径は３～４ｍｍ程度のものを使用する。これは、可動弁として機能するので軽量化を図るためである。 As shown in FIG. 2, the valve body 3 uses a ball valve. For the balls, for example, JIS standard ball bearing steel balls are used. This ball has a high roundness and has a mirror finish, and is suitable for enhancing sheet properties, and suitable for cost reduction by mass production. . When the valve body 3 is configured, a ball having a diameter of about 3 to 4 mm is used. This is to reduce the weight because it functions as a movable valve.
　また、ノズル体５において、弁体３と密着するシート５ｃ位置を含む傾斜面の角度は９０゜程度（８０゜～１００゜）である。この傾斜角は、シート５ｃ位置付近を研磨し、且つ真円度を高くするために最適な角度（研削機械をベストコンディションで使用できる）であり、弁体３とのシート性を極めて高く維持できるものである。なお、シート５ｃ位置を含む傾斜面を有するノズル体５は、焼入れによって硬度が高められており、また、脱磁処理により無用な磁気が除去されている。このような弁体構成により、燃料漏れのない噴射量制御が可能となる。また、コストパフォーマンスに優れた弁体構造を提供できる。 Further, in the nozzle body 5, the angle of the inclined surface including the position of the sheet 5c in close contact with the valve body 3 is about 90 ° (80 ° to 100 °). This inclination angle is an optimum angle for polishing the vicinity of the position of the seat 5c and increasing the roundness (the grinding machine can be used in the best condition), and the sheet property with the valve body 3 can be maintained extremely high. Is. In addition, the nozzle body 5 having the inclined surface including the position of the sheet 5c is increased in hardness by quenching, and unnecessary magnetism is removed by demagnetization treatment. With such a valve body configuration, it is possible to control the injection amount without fuel leakage. Moreover, the valve body structure excellent in cost performance can be provided.
　また、ノズルプレート６は、下凸形状にするために、凸面（下凸形状部）６Ａを形成するための製造工程においてパンチによる押し出しを行う。下凸形状部６Ａは、燃料噴射弁の外方に向かって凸形状に形成され、中心側（中心軸線１００側）から半径方向外方に向かって燃料が拡散していく燃料拡散室４３を構成する。燃料拡散室４３の底面（下面）はノズルプレート６によって構成され、燃料拡散室４３の天井面（上面）はノズル体５の下端面によって構成されている。 Further, the nozzle plate 6 is extruded by punching in a manufacturing process for forming a convex surface (down convex shape portion) 6A in order to form a downward convex shape. The downward convex portion 6A is formed in a convex shape toward the outside of the fuel injection valve, and constitutes a fuel diffusion chamber 43 in which the fuel diffuses radially outward from the center side (center axis 100 side). To do. The bottom surface (lower surface) of the fuel diffusion chamber 43 is configured by the nozzle plate 6, and the ceiling surface (upper surface) of the fuel diffusion chamber 43 is configured by the lower end surface of the nozzle body 5.
　燃料噴射弁が閉弁状態にあるときには、弁体３はノズル体５に溶接などで接合されたシート部材５aに設けられた円錐面からなる弁座面５bと当接することによって燃料のシールを保つようになっている。このとき、弁体３側の接触部（シート部）５ｃは球面によって形成されており、円錐面の弁座面と球面の接触はほぼ線接触の状態になっている。弁体３が上昇して弁体３とシート部材５ａに隙間が生じると、燃料は前記隙間を流れ出し、シート部材５aの開口部５ｄにて矢印１７の方向からノズルプレート６の上面に衝突する。その後、矢印１８のようにノズルプレート６の中央からノズルプレート６の表面に沿って流れる。燃料は、燃料噴射孔７を通過後、液膜９を形成する。液膜９は、表面張力波による不安定性や空気との剪断力により液滴１０へと分裂して、燃料の微粒化が達成される。 When the fuel injection valve is in the closed state, the valve body 3 keeps the fuel seal by contacting the valve seat surface 5b formed of a conical surface provided on the seat member 5a joined to the nozzle body 5 by welding or the like. It is like that. At this time, the contact portion (seat portion) 5c on the valve body 3 side is formed of a spherical surface, and the contact between the conical surface of the valve seat surface and the spherical surface is in a substantially line contact state. When the valve body 3 rises and a gap is formed between the valve body 3 and the seat member 5a, the fuel flows out of the gap and collides with the upper surface of the nozzle plate 6 from the direction of the arrow 17 at the opening 5d of the seat member 5a. Thereafter, the gas flows from the center of the nozzle plate 6 along the surface of the nozzle plate 6 as indicated by an arrow 18. The fuel forms a liquid film 9 after passing through the fuel injection hole 7. The liquid film 9 is split into droplets 10 due to instability due to surface tension waves and shearing force with air, and fuel atomization is achieved.
　本実施例では、開口部５ｄの半径は燃料噴射孔７の開口位置の半径よりも小さく、開口部５ｄから下凸形状部６Ａに流れ込んだ燃料は半径方向外方に向かって流れた後、燃料噴射孔７に流入する。開口部５ｄと燃料噴射孔７の開口位置との関係は、後述する他の実施例も同様である。 In this embodiment, the radius of the opening 5d is smaller than the radius of the opening position of the fuel injection hole 7, and the fuel that has flowed from the opening 5d into the downward convex portion 6A flows outward in the radial direction, and then the fuel It flows into the injection hole 7. The relationship between the opening 5d and the opening position of the fuel injection hole 7 is the same in other embodiments described later.
　次に、図３乃至図６を用いて、燃料流れと本実施例の効果について、説明する。 Next, the fuel flow and the effects of this embodiment will be described with reference to FIGS.
　図３は、本発明の第１実施例に係る燃料噴射弁のノズルプレートを弁体側から見た図である。図３では、燃料噴霧のターゲット方向を２方向に設定した場合について、各燃料噴射孔７の方向を矢印１１で示している。噴射孔の方向は、総称として方向１１とする。 FIG. 3 is a view of the nozzle plate of the fuel injection valve according to the first embodiment of the present invention as viewed from the valve body side. In FIG. 3, the direction of each fuel injection hole 7 is indicated by an arrow 11 when the target direction of the fuel spray is set to two directions. The direction of the injection hole is generally referred to as direction 11.
　各燃料噴射孔７は、図３の紙面上において、左右の方向に向けられている。すなわち、図３の紙面上において、左側に配置された複数の燃料噴射孔７のグループは燃料噴霧のターゲット方向が左方向に設定されており、右側に配置された複数の燃料噴射孔７のグループは燃料噴霧のターゲット方向が右方向に設定されている。図３では、２方向のターゲット方向に適用した例を示すが、ターゲット方向は放射方向など、２方向に限定するものではない。 Each fuel injection hole 7 is directed in the left-right direction on the paper surface of FIG. That is, the group of the plurality of fuel injection holes 7 arranged on the left side in FIG. 3 has the fuel spray target direction set to the left, and the group of the plurality of fuel injection holes 7 arranged on the right side. The fuel spray target direction is set to the right. Although FIG. 3 shows an example applied to two target directions, the target direction is not limited to two directions such as a radial direction.
　図４を用いて、本実施例における燃料の微粒化メカニズムについて説明する。図４は、本発明における、燃料の微粒化メカニズムの説明図である。なお、図４では、図２のノズルプレート６近傍の右半分の拡大図を示している。 The fuel atomization mechanism in this embodiment will be described with reference to FIG. FIG. 4 is an explanatory diagram of a fuel atomization mechanism in the present invention. 4 shows an enlarged view of the right half near the nozzle plate 6 of FIG.
　燃料通路部の開口部５ｄでの燃料流れ１７は、ノズルプレート６の上面に衝突して、速度分布８のように、ノズルプレート６の上面側に高速域を有する流れ場が形成される。本実施例では、ノズルプレート６の中心部から遠ざかるにつれて、前記曲面形状の曲率を大きくして、ノズルプレート６の上面へ流れを押し付ける効果を増加させることで、ノズルプレート６の上面側の高速域をさらに高速化している。ノズルプレート６の上面の流れは、曲面の接線方向に流れる性質があり、曲率が大きくなる分だけ図４で上方向に流れの方向が変化する。この流れが方向を変える分、ノズルプレート６の上面へ流れを押し付ける効果が得られる。 The fuel flow 17 at the opening 5d of the fuel passage portion collides with the upper surface of the nozzle plate 6, and a flow field having a high speed region is formed on the upper surface side of the nozzle plate 6 as in the velocity distribution 8. In the present embodiment, the curvature of the curved surface shape is increased as the distance from the center of the nozzle plate 6 increases, and the effect of pressing the flow toward the upper surface of the nozzle plate 6 is increased. Is even faster. The flow on the upper surface of the nozzle plate 6 has a property of flowing in the tangential direction of the curved surface, and the flow direction changes upward in FIG. 4 as the curvature increases. The effect of pressing the flow toward the upper surface of the nozzle plate 6 is obtained by the amount of the flow changing direction.
　図５を用いて、従来技術について説明する。図５は、従来発明における、燃料噴射弁の弁体先端の近傍を拡大した断面図である。 The conventional technology will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view of the vicinity of the tip of the valve body of the fuel injection valve in the conventional invention.
　従来技術では、図５のように、曲面形状の曲率は中心部から遠ざかっても増加することはなく、ノズルプレート６’の上面へ流れを押し付ける効果が得られない。 In the prior art, as shown in FIG. 5, the curvature of the curved surface shape does not increase even if it is far from the center, and the effect of pressing the flow against the upper surface of the nozzle plate 6 'cannot be obtained.
　さらに本実施例では、ノズルプレート６の中心部から遠ざかるにつれて、前記曲面形状の曲率を大きくすることにより、燃料噴射孔７の上流において、ノズルプレート６の曲面の接線方向（燃料の流れ方向）と燃料噴射孔７の中心軸方向（燃料の噴射方向）の方向変化が大きくなり、この結果、噴射孔内において、噴射方向に対して垂直な方向の流速成分を大きくすることが可能となり、燃料が噴射孔を出た時に、燃料の拡散効果が強くなって、燃料の微粒化がさらに促進される。 Further, in this embodiment, the curvature of the curved surface shape is increased as the distance from the center of the nozzle plate 6 increases, so that the tangential direction (fuel flow direction) of the curved surface of the nozzle plate 6 is upstream of the fuel injection hole 7. The direction change in the central axis direction (fuel injection direction) of the fuel injection hole 7 becomes large. As a result, the flow velocity component in the direction perpendicular to the injection direction can be increased in the injection hole, and the fuel When exiting the injection hole, the diffusion effect of the fuel becomes stronger and the atomization of the fuel is further promoted.
　この燃料の微粒化メカニズムについて、図６を用いて詳細に説明する。
図６は、本実施例と従来技術における、燃料の微粒化メカニズムの違いを説明した図である。なお、図６では図２のノズルプレート６近傍の右半分の拡大図を示している。 The fuel atomization mechanism will be described in detail with reference to FIG.
FIG. 6 is a diagram for explaining the difference in fuel atomization mechanism between the present embodiment and the prior art. 6 shows an enlarged view of the right half near the nozzle plate 6 of FIG.
　本実施例のノズルプレート６の上面６ａでの流れ方向６ａａと燃料噴射孔７内での燃料の噴射方向７ａとの成す角度１９ａに対して、従来技術のノズルプレート６’の上面６ｂでの流れ方向６ｂｂと燃料噴射孔７内での燃料の噴射方向７ａとの成す角度１９ｂが大きくなっている。このことは、本実施例の方が従来技術よりも流れの方向変化が大きく、噴射孔７内において、噴射方向に対して垂直な方向の流速成分を大きくなることを意味する。本実施例と従来技術とにおける流れの方向ベクトルの方向変化角度は、次のようになる。 With respect to the angle 19a formed by the flow direction 6aa on the upper surface 6a of the nozzle plate 6 of the present embodiment and the fuel injection direction 7a in the fuel injection hole 7, the flow on the upper surface 6b of the nozzle plate 6 'of the prior art. An angle 19b formed by the direction 6bb and the fuel injection direction 7a in the fuel injection hole 7 is large. This means that the flow direction change in the present embodiment is larger than that in the prior art, and the flow velocity component in the direction perpendicular to the injection direction is increased in the injection hole 7. The direction change angle of the flow direction vector in the present embodiment and the prior art is as follows.
　　　本実施例：１８０度 - １９ａ
　　　従来発明：１８０度 - １９ｂ
この結果、燃料が噴射孔７を出た時に、燃料の拡散効果が強くなって、燃料の微粒化がさらに促進される。 Example: 180 degrees-19a
Conventional invention: 180 degrees-19b
As a result, when the fuel exits the injection hole 7, the diffusion effect of the fuel becomes stronger and the atomization of the fuel is further promoted.
　本実施例では、ノズルプレート６の符号４０で示す範囲は平面で構成されている。平面は曲率が０の場合であり、本実施例では、下凸形状部６Ａが中心部から半径方向外方に向かって曲率０から増加するように構成されている。 In this embodiment, the range indicated by reference numeral 40 of the nozzle plate 6 is a flat surface. The plane is a case where the curvature is 0. In this embodiment, the downward convex portion 6A is configured to increase from the curvature 0 toward the radially outward direction from the center portion.
　別の見方をすれば、本実施例では、燃料噴射孔７の入口開口面が形成されるノズルプレート６の上面部分は、燃料噴射孔７の入口開口面よりも半径方向内方の部分を延長した仮想面４２よりも、前記半径方向内方部分或いは仮想面４２の曲率中心Ｏ側に位置している（図４参照）。すなわち、燃料噴射孔７の入口開口面が形成されるノズルプレート６の上面部分は、仮想面４２よりも燃料拡散室４３の天井面（上面）５ｅ側に位置している。天井面５ｅは、燃料拡散室４３の、凸形状部６Ａを構成するノズルプレート６と対向する壁面である。 From another point of view, in this embodiment, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed extends radially inward from the inlet opening surface of the fuel injection hole 7. It is located on the radius direction inner side of the virtual surface 42 or on the curvature center O side of the virtual surface 42 (see FIG. 4). That is, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is located closer to the ceiling surface (upper surface) 5 e side of the fuel diffusion chamber 43 than the virtual surface 42. The ceiling surface 5e is a wall surface of the fuel diffusion chamber 43 that faces the nozzle plate 6 constituting the convex portion 6A.
　本実施例では、前記半径方向内方部分、すなわち下凸形状部６Ａの中心部は平面であるため、曲率中心は図４の紙面上において、上方に向かって無限大離れた位置にある。そして、燃料噴射孔７の入口開口面は、平面で構成された中央部４０に対して半径方向外方に位置し、中心から離れるに従って曲率が増加する周辺部４１に開口している。 In the present embodiment, the radially inner portion, that is, the center portion of the downward convex portion 6A is a flat surface, so that the center of curvature is located at an infinite distance upward on the paper surface of FIG. The inlet opening surface of the fuel injection hole 7 is located radially outward with respect to the flat central portion 40 and opens to the peripheral portion 41 where the curvature increases as the distance from the center increases.
　平面の曲率中心は、図４の紙面上において、ノズルプレート６に対して下方に向かって無限大離れた位置にとることも可能ではある。しかし、下凸形状部６Ａはノズルプレート６に対して上側に曲率中心を配置して、下側に向かって凸状となる部分である。すなわち、下凸形状部６Ａの曲率中心は、本来、ノズルプレート６に対して上側に配置され、平面はこのような下凸形状部６Ａの特殊な例である。従って、下凸形状部６Ａに構成される平面の曲率中心は、図４の紙面上において、ノズルプレート６に対して上側に配置されるものとする。 It is also possible for the center of curvature of the plane to be located at an infinite distance downward from the nozzle plate 6 on the paper surface of FIG. However, the downward convex portion 6A is a portion that has a center of curvature on the upper side with respect to the nozzle plate 6 and is convex downward. That is, the center of curvature of the downward convex portion 6A is originally disposed above the nozzle plate 6, and the plane is a special example of such downward convex portion 6A. Therefore, it is assumed that the center of curvature of the plane formed in the downward convex portion 6A is arranged on the upper side with respect to the nozzle plate 6 on the paper surface of FIG.
　なお、周辺部４１の曲率は０よりも大きな一定の値に設定されてもよい。或いは、中央部４０が周辺部４１に設定される曲率よりも小さな値でかつ０よりも大きな値の曲率に設定されてもよい。 Note that the curvature of the peripheral portion 41 may be set to a constant value greater than zero. Alternatively, the curvature of the central portion 40 may be set to a value smaller than the curvature set to the peripheral portion 41 and larger than 0.
　本発明の第２実施例に係わる燃料噴射弁について、図７及び図８を用いて以下説明する。実施例１の説明で使用した図と同一の番号が割り当てられているものは、実施例１と同一もしくは同等の機能を有するものであり説明を省略する。 A fuel injection valve according to the second embodiment of the present invention will be described below with reference to FIGS. Those assigned the same numbers as those used in the description of the first embodiment have the same or equivalent functions as those of the first embodiment, and the description thereof will be omitted.
　図７は本発明の第２実施例に係る燃料噴射弁の弁体先端の近傍を拡大した断面図である。図７に示す第２実施例では、第１実施例の図２に対して、ノズルプレート６の曲面形状（下凸形状部）６Ａが、２種類の曲率で形成されていることを特徴とする。すなわち、下凸形状部６Ａは、ノズルプレート６の中央部７０では曲率が第１の曲率に設定され、ノズルプレート６の中央部７０に対して半径方向外方に位置する周辺部７１では曲率が第２の曲率に設定される。そして、燃料噴射孔７の入口開口面は第２の曲率に形成された周辺部７１に開口している。第２の曲率は第１の曲率よりも大きな値である。この場合、第１の曲率は０であってもよい。すなわち、ノズルプレート６の中央部７０が平面で構成されてもよい。 FIG. 7 is an enlarged cross-sectional view of the vicinity of the tip of the valve body of the fuel injection valve according to the second embodiment of the present invention. The second embodiment shown in FIG. 7 is characterized in that the curved surface shape (downward convex portion) 6A of the nozzle plate 6 is formed with two kinds of curvatures as compared to FIG. 2 of the first embodiment. . That is, the downward convex portion 6 </ b> A has a curvature set to the first curvature at the central portion 70 of the nozzle plate 6, and has a curvature at the peripheral portion 71 located radially outward with respect to the central portion 70 of the nozzle plate 6. The second curvature is set. The inlet opening surface of the fuel injection hole 7 opens to the peripheral portion 71 formed with the second curvature. The second curvature is a larger value than the first curvature. In this case, the first curvature may be zero. That is, the central portion 70 of the nozzle plate 6 may be configured as a flat surface.
　本実施例においても、燃料噴射孔７の入口開口面が形成されるノズルプレート６の上面部分は、燃料噴射孔７の入口開口面よりも半径方向内方の部分を延長した仮想面７２よりも、前記半径方向内方部分或いは仮想面７２の曲率中心側に位置している。すなわち、燃料噴射孔７の入口開口面が形成されるノズルプレート６の上面部分は、仮想面７２よりも燃料拡散室４３の天井面（上面）５ｅ側に位置している。 Also in the present embodiment, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is more than the virtual surface 72 that extends inward in the radial direction from the inlet opening surface of the fuel injection hole 7. , Located in the radially inner portion or the center of curvature of the virtual plane 72. That is, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is located closer to the ceiling surface (upper surface) 5 e side of the fuel diffusion chamber 43 than the virtual surface 72.
　本実施例でも第１実施例で示した図２と同等な効果が得られる。 In this embodiment, the same effect as in FIG. 2 shown in the first embodiment can be obtained.
　なお、本発明の第１および第２実施例に係る燃料噴射弁において、ノズルプレート６の曲率の変化は傾きの異なる平面と傾斜面（テーパー面或いは円錐面）の組合せで構成することが可能である。図８にその例を示す。図８は、本発明の第２実施例に係る燃料噴射弁において、ノズルプレートの曲率の変化を２つの平面で構成した例である。 In the fuel injection valves according to the first and second embodiments of the present invention, the change in the curvature of the nozzle plate 6 can be constituted by a combination of a plane having a different inclination and an inclined surface (tapered surface or conical surface). is there. An example is shown in FIG. FIG. 8 is an example in which the change in the curvature of the nozzle plate is constituted by two planes in the fuel injection valve according to the second embodiment of the present invention.
　図８に示すように、下凸形状部６Ａは、ノズルプレート６の中央部８０が燃料噴射弁の中心軸線１００に垂直な平面（曲率＝０）で構成され、ノズルプレート６の中央部７０に対して半径方向外方に位置する周辺部８１が中央部８０の平面に対して傾斜した傾斜面（テーパー面或いは円錐面）で構成されている。周辺部８１のテーパー面は、内周側が外周側に対して下方に位置するように傾斜している。中央部８０は図７の中央部４０に対応し、周辺部８１は図７の周辺部４１に対応している。燃料噴射孔７の入口開口面は周辺部８１のテーパー面に開口している。 As shown in FIG. 8, the downward convex portion 6 </ b> A is configured such that the central portion 80 of the nozzle plate 6 is a plane (curvature = 0) perpendicular to the central axis 100 of the fuel injection valve. On the other hand, the peripheral portion 81 located outward in the radial direction is configured by an inclined surface (tapered surface or conical surface) inclined with respect to the plane of the central portion 80. The tapered surface of the peripheral portion 81 is inclined so that the inner peripheral side is positioned below the outer peripheral side. The central portion 80 corresponds to the central portion 40 in FIG. 7, and the peripheral portion 81 corresponds to the peripheral portion 41 in FIG. The inlet opening surface of the fuel injection hole 7 opens to the tapered surface of the peripheral portion 81.
　このような構成であっても、第１実施例と同様な効果が得られる。 Even with such a configuration, the same effect as in the first embodiment can be obtained.
　本発明の第３実施例に係わる燃料噴射弁について、図９を用いて以下説明する。図９は、本発明の第３実施例に係る燃料噴射弁の弁体先端の近傍を拡大した断面図である。第１実施例の説明で使用した図と同一の番号が割り当てられているものは、第１実施例と同一もしくは同等の機能を有するものであり説明を省略する。 A fuel injection valve according to a third embodiment of the present invention will be described below with reference to FIG. FIG. 9 is an enlarged cross-sectional view of the vicinity of the tip of the valve body of the fuel injection valve according to the third embodiment of the present invention. Those assigned the same numbers as those used in the description of the first embodiment have the same or equivalent functions as those in the first embodiment, and will not be described.
　第３実施例では、シート部材５ａの下流方向に設けた開口部５ｄが、ノズルプレート６の中心からみて、燃料噴射孔７よりも内側にあり、かつノズルプレート６の中心側（中心部）９０を、上に凸の曲面６Ｂと、上に凸の曲面６Ｂの外周側（半径方向外方）に形成した下に凸の曲面６Ｃとで構成している。下に凸の曲面６Ｃの外周側、すなわち中心部９０の半径方向外方の周辺部９１には、傾斜面（テーパー面或いは円錐面）が設けられ、この傾斜面に燃料噴射孔７の入口開口面が設けられている。 In the third embodiment, the opening 5 d provided in the downstream direction of the sheet member 5 a is inside the fuel injection hole 7 when viewed from the center of the nozzle plate 6, and the center side (center part) 90 of the nozzle plate 6. Is formed of an upwardly convex curved surface 6B and a downwardly convex curved surface 6C formed on the outer peripheral side (outward in the radial direction) of the upwardly convex curved surface 6B. An inclined surface (tapered surface or conical surface) is provided on the outer peripheral side of the downwardly convex curved surface 6C, that is, the peripheral portion 91 radially outward of the central portion 90, and the inlet opening of the fuel injection hole 7 is provided on this inclined surface. A surface is provided.
　周辺部９１に形成されたテーパー面は、下に凸の曲面６Ｃを延長した仮想面９２よりも曲面６Ｃの曲率中心側に位置している。このテーパー面９１は、曲面６Ｃの曲率よりも大きな曲率で、中心側（内周側）から外周側に向かって曲率が変化するように構成してもよい。或いは、テーパー面９１は、曲面６Ｃの曲率よりも大きな曲率で、かつ中心側（内周側）から外周側に向かって一定の曲率となるように、構成してもよい。 The tapered surface formed in the peripheral portion 91 is located closer to the center of curvature of the curved surface 6C than the virtual surface 92 obtained by extending the downwardly convex curved surface 6C. The tapered surface 91 may be configured to have a curvature larger than that of the curved surface 6 </ b> C, and the curvature may change from the center side (inner peripheral side) toward the outer peripheral side. Or you may comprise the taper surface 91 so that it may have a curvature larger than the curvature of the curved surface 6C, and may become a fixed curvature toward the outer peripheral side from a center side (inner peripheral side).
　本実施例では、燃料噴射孔７の入口開口面が形成されるノズルプレート６の上面部分は、仮想面９２よりも仮想面９２及び下に凸の曲面６Ｃの曲率中心Ｏ側に位置している。すなわち、燃料噴射孔７の入口開口面が形成されるノズルプレート６の上面部分は、仮想面９２よりも燃料拡散室４３の天井面（上面）５ｅ側に位置している。 In the present embodiment, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is located on the imaginary surface 92 and on the curvature center O side of the curved surface 6C protruding downward from the imaginary surface 92. . That is, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is located closer to the ceiling surface (upper surface) 5 e side of the fuel diffusion chamber 43 than the virtual surface 92.
　第３実施例において、燃料噴射弁の基本動作は実施例１と２と同じである。また燃料噴霧のターゲット方向に関しても実施例１と２と同じである。 In the third embodiment, the basic operation of the fuel injection valve is the same as in the first and second embodiments. Further, the fuel spray target direction is the same as in the first and second embodiments.
　本実施例では、図２の例に比べてノズルプレート６の上面の曲率変化を大きくすることが可能であり、これにより前述の理由により燃料の微粒化を向上することができる。さらに本実施例では、ノズルプレート６の上面の空間を図２の例に比べて小さくすることが可能となり、その結果、負圧下での燃料噴射特性も改善される。 In this embodiment, it is possible to increase the change in curvature of the upper surface of the nozzle plate 6 as compared with the example of FIG. 2, thereby improving the atomization of the fuel for the reasons described above. Furthermore, in this embodiment, the space on the upper surface of the nozzle plate 6 can be made smaller than that in the example of FIG. 2, and as a result, the fuel injection characteristics under negative pressure are also improved.
　第３実施例において、燃料噴射孔７の入口開口面を下に凸の曲面６Ｃ上に設けてもよい。この場合も、燃料噴射孔７の入口開口面が形成されるノズルプレート６の上面部分は、上に凸の曲面６Ｂの仮想面９３（図９参照）よりも燃料拡散室４３の天井面（上面）５ｅ側に位置することになる。 In the third embodiment, the inlet opening surface of the fuel injection hole 7 may be provided on the curved surface 6C that protrudes downward. Also in this case, the upper surface portion of the nozzle plate 6 where the inlet opening surface of the fuel injection hole 7 is formed is higher than the imaginary surface 93 (see FIG. 9) of the upwardly curved surface 6B. ) 5e side.
　これにより、燃料噴射孔７の上流において、ノズルプレート６の曲面の接線方向（燃料の流れ方向）と燃料噴射孔７の中心軸方向（燃料の噴射方向）の方向変化が大きくなる。
この結果、噴射孔７内において、噴射方向と垂直な方向の流速成分を大きくすることが可能となる。そして、燃料が噴射孔を出た時に、燃料の拡散効果が強くなって、燃料の微粒化がさらに促進される。 Thereby, upstream of the fuel injection hole 7, the direction change in the tangential direction (fuel flow direction) of the curved surface of the nozzle plate 6 and the central axis direction (fuel injection direction) of the fuel injection hole 7 becomes large.
As a result, the flow velocity component in the direction perpendicular to the injection direction can be increased in the injection hole 7. And when a fuel exits an injection hole, the diffusion effect of a fuel becomes strong and atomization of a fuel is further accelerated | stimulated.
　燃料噴射孔７の入口開口面を下に凸の曲面６Ｃ上に設ける場合、下に凸の曲面６Ｃの曲率を、第１実施例の周辺部４１のように、半径方向外方に向かって増加させてもよい。或いは、下に凸の曲面６Ｃを、中心側（内周側）の曲率を第１の曲率を有する形状にし、この中心側に対して半径方向外方（外周側）を第１の曲率よりも大きな第２の曲率を有する形状にしてもよい。この場合、第１の曲率と第２の曲率とはそれぞれ一定値に設定される。 When the inlet opening surface of the fuel injection hole 7 is provided on the downwardly convex curved surface 6C, the curvature of the downwardly convex curved surface 6C is increased outward in the radial direction like the peripheral portion 41 of the first embodiment. You may let them. Alternatively, the downwardly convex curved surface 6C has a shape in which the curvature on the center side (inner circumference side) has the first curvature, and the outer side in the radial direction (outer circumference side) with respect to the center side is more than the first curvature. You may make it the shape which has a big 2nd curvature. In this case, the first curvature and the second curvature are each set to a constant value.
　これにより、前述の理由で更なる燃料の微粒化が促進される。 This promotes further atomization of fuel for the reasons described above.
　上述した各実施例によれば、下凸形状部６Ａを例えばパンチで形成することにより製造コストの低減をはかり、かつ微粒化特性の良い燃料噴霧を形成可能な燃料噴射弁を提供することが可能である。なお本発明に係る燃料噴射弁では、ノズルプレートを下に凸の曲面形状とし、ノズルプレートの中心部から遠ざかるにつれて、前記曲面形状の曲率が大きくなるような簡素な構造となっている。このノズルプレートの構造により、噴射孔内において、噴射方向と垂直な方向の流速成分を大きくすることが可能となり、燃料が噴射孔を出た時に、燃料の拡散効果が強くなって燃料の微粒化が促進される。 According to each of the embodiments described above, it is possible to provide a fuel injection valve capable of reducing the manufacturing cost by forming the downward convex portion 6A with, for example, a punch and forming a fuel spray with good atomization characteristics. It is. The fuel injection valve according to the present invention has a simple structure in which the nozzle plate has a curved surface shape convex downward, and the curvature of the curved surface shape increases as the distance from the center of the nozzle plate increases. With this nozzle plate structure, it is possible to increase the flow velocity component in the direction perpendicular to the injection direction in the injection hole, and when the fuel exits the injection hole, the fuel diffusion effect becomes stronger and the fuel atomizes. Is promoted.
　なお、本発明は上記した各実施例に限定されるものではなく、様々な変形例が含まれる。例えば、上記した実施例は本発明を分かりやすく説明するために詳細に説明したものであり、必ずしも全ての構成を備えるものに限定されるものではない。また、ある実施例の構成の一部を他の実施例の構成に置き換えることが可能であり、また、ある実施例の構成に他の実施例の構成を加えることも可能である。また、各実施例の構成の一部について、他の構成の追加・削除・置換をすることが可能である。 In addition, this invention is not limited to each above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.
　１…燃料噴射弁、２…ケーシング、２ａ…燃料供給口、３…弁体、３ｃ…シート部、４…アンカー、５…ノズル体、５ａ…シート部材、５ｂ…弁座面、５ｃ…シート部、５ｄ…開口部、５ｅ…ノズル体の下端面（燃料拡散室の天井面）、６…ノズルプレート、６Ａ…下凸形状部、６Ｂ…上に凸の曲面、６Ｃ…下に凸の曲面、６ａ…本発明のノズルプレート上面、６ａａ…本発明のノズルプレート上面での流れ方向、６ｂ…従来技術のノズルプレート上面、６ｂｂ…従来発明のノズルプレート上面での流れ方向、７…燃料噴射孔、７ａ…燃料噴射孔内での燃料の噴射方向、８…ノズルプレート上面に衝突した燃料の速度分布、９…燃料液膜、１０…液滴、１１…噴射孔の傾斜方向（燃料の噴射方向）、１２…スプリング、１３…スプリングアジャスタ、１４…電磁コイル、１５…固定コア、１６…ヨーク、１７…弁部材よりも下流側に配置された燃料通路部の開口部での燃料流れ、１８…ノズルプレート上での燃料流れ、１９ａ…本発明のノズルプレート上面６ａでの流れ方向６ａａと燃料噴射孔内での燃料の噴射方向７ａの成す角度、１９ｂ…本発明のノズルプレート上面６ａでの流れ方向６ａａと燃料噴射孔内での燃料の噴射方向７ａの成す角度、２０…フィルタ、２１…Ｏリング、２２…樹脂カバー、２３…コネクタ、２４…プロテクタ、２５…Ｏリング、４０…下凸形状部の中心部、４１…下凸形状部の周辺部、４２…中心部４０を延長した仮想面、４３…燃料拡散室、７０…下凸形状部の中心部、７１…下凸形状部の周辺部、７２…中心部７０を延長した仮想面、８０…下凸形状部の中心部、８１…下凸形状部の周辺部、９０…下凸形状部の中心部、９１…下凸形状部の周辺部、９２…下に凸の曲面６Ｃを延長した仮想面、９３…上に凸の曲面６Ｂを延長した仮想面。 DESCRIPTION OF SYMBOLS 1 ... Fuel injection valve, 2 ... Casing, 2a ... Fuel supply port, 3 ... Valve body, 3c ... Seat part, 4 ... Anchor, 5 ... Nozzle body, 5a ... Seat member, 5b ... Valve seat surface, 5c ... Seat part 5d: Opening portion, 5e: Lower end surface of the nozzle body (ceiling surface of the fuel diffusion chamber), 6 ... Nozzle plate, 6A ... Lower convex shape portion, 6B ... Upper convex curved surface, 6C ... Lower convex curved surface, 6a ... the upper surface of the nozzle plate of the present invention, 6aa ... the flow direction on the upper surface of the nozzle plate of the present invention, 6b ... the upper surface of the nozzle plate of the prior art, 6bb ... the flow direction on the upper surface of the nozzle plate of the conventional invention, 7 ... fuel injection holes, 7a ... Fuel injection direction in fuel injection hole, 8 ... Speed distribution of fuel colliding with nozzle plate upper surface, 9 ... Fuel liquid film, 10 ... Droplet, 11 ... Inclination direction of injection hole (fuel injection direction) 12 ... Spring 13 ... Spring 14, electromagnetic coil, 15, fixed core, 16, yoke, 17, fuel flow at the opening of the fuel passage portion disposed downstream of the valve member, 18, fuel flow on the nozzle plate, 19 a ... An angle formed by the flow direction 6aa on the nozzle plate upper surface 6a of the present invention and the fuel injection direction 7a in the fuel injection hole, 19b ... The flow direction 6aa on the nozzle plate upper surface 6a of the present invention and the fuel injection hole Angle formed by the fuel injection direction 7a, 20 ... filter, 21 ... O-ring, 22 ... resin cover, 23 ... connector, 24 ... protector, 25 ... O-ring, 40 ... center of the lower convex shape portion, 41 ... lower convex Peripheral part of the shape part, 42 ... Virtual plane obtained by extending the central part 40, 43 ... Fuel diffusion chamber, 70 ... Central part of the downward convex part, 71 ... Peripheral part of the downward convex part, 72 ... Extending the central part 70 Virtual surface, 80 ... Center portion of convex shape portion, 81 ... peripheral portion of lower convex shape portion, 90 ... central portion of lower convex shape portion, 91 ... peripheral portion of lower convex shape portion, 92 ... virtual surface obtained by extending convex curved surface 6C downward 93 ... A virtual surface obtained by extending the convex curved surface 6B upward.

Claims (8)

  1. 　弁座を有するシート部材と、前記シート部材に離座及び着座する弁体と、前記シート部材の前記弁体が離座及び着座するシート部よりも下流側に形成された開口部と、前記開口部の下流側に配置されたノズルプレートとを備え、前記ノズルプレートは外方に向けて凸状となる凸形状部を有すると共に、前記開口部よりも半径方向外方に形成された燃料噴射孔を有し、前記凸形状部の内側に燃料が半径方向外方に向かって拡散するように流れる燃料拡散室が形成された燃料噴射弁において、
    　前記凸形状部の中心部に対して半径方向外方に位置する周辺部が、前記中心部を半径方向外方に延長した仮想面よりも、前記燃料拡散室の前記凸形状部と対向する天井面側に位置し、
    　前記燃料噴射孔の入口開口面が前記周辺部に開口することを特徴とする燃料噴射弁。     A seat member having a valve seat; a valve body that is separated from and seated on the seat member; an opening formed on a downstream side of a seat portion on which the valve body of the seat member is separated and seated; and the opening A nozzle plate disposed on the downstream side of the nozzle portion, the nozzle plate having a convex portion that is convex outward, and a fuel injection hole that is formed radially outward from the opening portion And a fuel injection valve in which a fuel diffusion chamber that flows so as to diffuse radially outward is formed inside the convex portion.
    A ceiling that is located radially outward with respect to the central portion of the convex shape portion is opposed to the convex shape portion of the fuel diffusion chamber rather than a virtual surface that extends the central portion radially outward. Located on the surface side,
    The fuel injection valve, wherein an inlet opening surface of the fuel injection hole opens in the peripheral portion.
  2. 　請求項１に記載の燃料噴射弁において、
    　前記凸形状部の前記中心部の曲率よりも前記周辺部の曲率の方が大きいことを特徴とする燃料噴射弁。     The fuel injection valve according to claim 1, wherein
    The fuel injection valve characterized in that the curvature of the peripheral portion is larger than the curvature of the central portion of the convex portion.
  3. 　請求項２に記載の燃料噴射弁において、
    　前記凸形状部は、中心側から半径方向外方に向かって遠ざかるにつれて、曲率が増加することを特徴とする燃料噴射弁。     The fuel injection valve according to claim 2,
    The fuel injection valve characterized in that the curvature increases as the convex portion moves away from the center side in the radial direction outward.
  4. 　請求項２に記載の燃料噴射弁において、
    　前記凸形状部の前記中心部が第１の曲率で形成され、前記周辺部の曲率が第２の曲率で形成され、前記第１の曲率と前記第２の曲率とはそれぞれ一定値に設定されたことを特徴とする燃料噴射弁。     The fuel injection valve according to claim 2,
    The central portion of the convex portion is formed with a first curvature, the curvature of the peripheral portion is formed with a second curvature, and the first curvature and the second curvature are each set to a constant value. A fuel injection valve characterized by that.
  5. 　請求項１に記載の燃料噴射弁において、
    　前記凸形状部の前記中心部を上に凸の第１の曲面とし、前記上に凸の第１の曲面の外周側に下に凸の第２の曲面を設けたことを特徴とする燃料噴射弁。     The fuel injection valve according to claim 1, wherein
    A fuel injection, wherein the central portion of the convex portion is a first curved surface that is convex upward, and a second curved surface that is convex downward is provided on the outer peripheral side of the upward convex first curved surface. valve.
  6. 　請求項５に記載の燃料噴射弁において、
    　前記燃料噴射孔の入口開口面を前記第２の曲面に開口したことを特徴とする燃料噴射弁。     The fuel injection valve according to claim 5,
    A fuel injection valve characterized in that an inlet opening surface of the fuel injection hole is opened in the second curved surface.
  7. 　請求項６に記載の燃料噴射弁において、
    　前記第２の曲面を、中心側から半径方向外方に向かって遠ざかるにつれて、曲率が増加するように形成したことを特徴とする燃料噴射弁。     The fuel injection valve according to claim 6, wherein
    The fuel injection valve, wherein the second curved surface is formed so that the curvature increases as it moves away from the center side in the radially outward direction.
  8. 　請求項６に記載の燃料噴射弁において、
    　前記第２の曲面は、中心側が第１の曲率で形成され、前記中心側に対して半径方向外方側の部分が第２の曲率で形成され、前記第１の曲率と前記第２の曲率とはそれぞれ一定値に設定されたことを特徴とする燃料噴射弁。     The fuel injection valve according to claim 6, wherein
    The second curved surface is formed with a first curvature at a center side, and a portion radially outward with respect to the center side is formed with a second curvature, and the first curvature and the second curvature are formed. And is a fuel injection valve characterized in that each is set to a constant value.
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