JP2014227934A - Fuel injection valve - Google Patents
Fuel injection valve Download PDFInfo
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この発明は、自動車の内燃機関などへの燃料供給に使用される燃料噴射弁に係り、特に噴霧特性における微粒化の促進、及び温度や雰囲気圧等の変化に伴う流量特性（静的流量、動的流量）の変化の抑制を図ったものである。 The present invention relates to a fuel injection valve used for supplying fuel to an internal combustion engine of an automobile, and in particular, promotes atomization in spray characteristics and flow characteristics (static flow, dynamics) associated with changes in temperature and atmospheric pressure. This is intended to suppress changes in the flow rate.
近年、自動車などの排出ガス規制が強化される中、燃料噴射弁から噴射される燃料噴霧噴射方向の自由度及び微粒化の向上が求められており、特に燃料噴霧の微粒化についてはこれまで既に各種の検討がなされている。
例えば、特許文献１に記載の燃料噴射弁では、噴孔プレートと弁座の間に燃料通路と噴孔とを連通する円盤状の燃料キャビティが設けられ、キャビティの軸方向高さが外周端に向かって低減するテーパ状となる形状が開示されている。燃料シート部から燃料キャビティ中央部に流れ込んだ燃料は、その流れの方向を変えて中央部から燃料キャビティの径方向外側に向かって流れ、噴孔へと突入する。その際に、軸方向高さが外周側に向かってテーパ状に低減していることから、燃料は速度を維持したまま噴孔へと突入し、噴射された燃料の微粒化が促進される構成となっている。
In recent years, as exhaust gas regulations for automobiles and the like have been strengthened, improvement in the degree of freedom and atomization of the direction of fuel spray injected from the fuel injection valve has been demanded. Various studies have been made.
For example, in the fuel injection valve described in Patent Document 1, a disk-shaped fuel cavity that connects the fuel passage and the nozzle hole is provided between the nozzle hole plate and the valve seat, and the axial height of the cavity is at the outer peripheral end. The shape which becomes the taper shape which reduces toward is disclosed. The fuel that has flowed into the center of the fuel cavity from the fuel seat portion changes its flow direction, flows from the center portion toward the outside in the radial direction of the fuel cavity, and enters the injection hole. At that time, since the axial height is reduced toward the outer peripheral side, the fuel enters the nozzle hole while maintaining the speed, and the atomization of the injected fuel is promoted. It has become.
又、例えば特許文献２に記載の燃料噴射弁では、弁体が下流側へ移動するときに開弁する外開弁方式において、弁体が弁座に当接するシート部より下流側に噴射孔を有するプレートを設けるとともに、プレートと弁体の端面の間に開弁時に噴射孔に通ずるキャビティを設けており、燃料シート面を通過した燃料が、外周部より弁座中心に向かうことで流れが加速されて噴孔へ突入するため、燃料噴霧の微粒化が促進される構成となっている。 Further, for example, in the fuel injection valve described in Patent Document 2, in the external valve opening system that opens when the valve body moves downstream, an injection hole is provided on the downstream side of the seat portion where the valve body abuts the valve seat. In addition to providing a plate with a cavity between the plate and the end face of the valve body that leads to the injection hole when the valve is opened, the fuel that has passed through the fuel seat surface is accelerated from the outer periphery toward the valve seat center In order to enter the nozzle hole, the atomization of the fuel spray is promoted.
又、例えば特許文献３に記載の燃料噴射弁（特許文献３の図１参照）においては、シート部を通過した燃料は、例えば円筒形に構成されたキャビティ部を通過し、プレートに設けられた噴孔より噴射されると記載されている。このような構成においては、シート部を通過した燃料は、キャビティ内で流れが反転又は大きく屈折することなく噴孔へと到達し、噴射される。 Further, for example, in the fuel injection valve described in Patent Document 3 (see FIG. 1 of Patent Document 3), the fuel that has passed through the seat portion is provided on the plate, for example, through a cavity portion configured in a cylindrical shape. It is described that it is ejected from the nozzle hole. In such a configuration, the fuel that has passed through the seat portion reaches the injection hole without being reversed or largely refracted in the cavity, and is injected.
又、例えば特許文献４に記載の燃料噴射弁（特許文献４の図３Ａ参照）の構成においては、シート部を通過した燃料の主流が、噴孔の燃料噴射弁軸心側の内壁面に直接衝突するように噴孔が配置されている。シートを通過した燃料は、噴孔入口部で剥離して液膜状となり、更に噴孔壁に衝突して押し付けられることで噴孔の曲率に沿った流れとなり、噴孔内で空気との混合が促進され、噴孔の出口から三日月状の液膜として拡散され、燃料の微粒化が促進されるとしている。 Further, for example, in the configuration of the fuel injection valve described in Patent Document 4 (see FIG. 3A of Patent Document 4), the main flow of the fuel that has passed through the seat portion is directly applied to the inner wall surface of the injection hole on the shaft side of the fuel injection valve. The nozzle holes are arranged so as to collide. The fuel that has passed through the sheet peels off at the injection hole inlet and forms a liquid film. Further, it collides with the injection hole wall and is pressed to flow along the curvature of the injection hole, and mixes with air in the injection hole. Is promoted and diffused as a crescent-shaped liquid film from the outlet of the nozzle hole, which promotes atomization of fuel.
特許文献１及び特許文献２では、燃料流路内で少なくとも一度は燃料流れが反転しており、流れの反転時に燃料の圧力損失が発生する。このため、圧力損失した分、噴孔出口部における流速が低下してしまうことから、噴射される燃料の空気との相対速度が低下し、空気が燃料液滴を分裂させるせん断力が低下、すなわち燃料噴霧の微粒化も十分なされない問題点がある。 In Patent Document 1 and Patent Document 2, the fuel flow is reversed at least once in the fuel flow path, and fuel pressure loss occurs when the flow is reversed. For this reason, since the flow velocity at the nozzle hole outlet portion is reduced by the amount of pressure loss, the relative speed of the injected fuel with the air is reduced, and the shear force that splits the fuel droplets is reduced. There is a problem that atomization of the fuel spray is not sufficient.
一般的に、燃料噴霧の微粒化の手法として噴孔の小径化、多噴孔化が知られているが、特許文献３の構成で噴孔を多噴孔化した場合、各噴孔の距離が接近し、各噴孔から噴射された液柱が噴孔の下流側で衝突することにより燃料噴霧の微粒化が妨げられる問題や、各噴孔の距離が接近しすぎるためにプレートの強度上配置できないなどの問題が発生する。
特許文献３の弁体先端形状、キャビティ部構成において、多噴孔配置するためには、キャビティ径を拡大する必要があり、その場合上記キャビティ部の体積が大きくなってしまうことから、雰囲気変化に伴う流量変化（静的流量、動的流量）が大きくなってしまう問題が生じる。
特許文献４では、噴孔部で燃料流れを急変させるような構成となっていることから、噴孔部において大きく圧力損失が発生し、噴孔出口部における流速が低下し、従って燃料噴霧の微粒化も十分なされない問題点がある。
この発明は、このような問題点を解決することを目的とするものである。
Generally, as a method for atomizing fuel spray, it is known to reduce the diameter of a nozzle hole and to increase the number of nozzle holes. And the liquid column injected from each nozzle hole collides on the downstream side of the nozzle hole, which prevents the atomization of the fuel spray from being disturbed. Problems such as inability to place occur.
In the valve body tip shape and the cavity portion configuration of Patent Document 3, in order to arrange the multiple injection holes, it is necessary to enlarge the cavity diameter, and in this case, the volume of the cavity portion becomes large. The accompanying flow rate change (static flow rate, dynamic flow rate) becomes large.
In Patent Document 4, since the fuel flow is suddenly changed at the nozzle hole portion, a large pressure loss is generated at the nozzle hole portion, the flow velocity at the nozzle hole outlet portion is decreased, and therefore the fine particles of the fuel spray are generated. There is a problem that it is not enough.
The object of the present invention is to solve such problems.
この発明に係わる燃料噴射弁は、複数の噴孔を有する噴孔プレート、この噴孔プレートと共にキャビティを形成し端面が下流側に向かって拡径する弁座シート部を有する弁座、及び上記弁座シート部のシート面と離接して上記噴孔を開閉する先端弁部を有する弁体を備え、上記弁体が下流側へ移動することにより開弁すると共に上記先端弁部が上記噴孔プレートに当接することで開弁動作が終了する外開弁方式の燃料噴射装置であって、
上記弁座シート部の下流側には、上記シート面に連続して延在し且つ傾斜角を異にする延長テーパ面が形成され、上記先端弁部は、上記シート面と離接する弁体シート部と、開弁終了時に上記噴孔プレートに当接する底部とで形成され、上記噴孔の入口部は、上記先端弁部の最外周縁部より上記弁座の弁座軸心の径方向外側に配置されると共に上記噴孔の入口部の中心は、上記シート面の下流側への延長線と上記噴孔プレートが交差することにより上記噴孔プレートに形成される仮想円の内側に配置され、かつ上記噴孔の出口部の中心は、上記噴孔の入口部の中心に対して上記弁座軸心の径方向外側に配置され、かつ上記弁座軸心と上記弁座シート部のシート面とがなす狭み角をα（≦９０°）、上記弁座軸心と上記延長テーパ面とがなす狭み角をβ（≦９０°）、上記噴孔プレートの板厚方向と上記噴孔の軸心がなす噴孔角をγとした時に、|α−β|≦２０°、かつ|α−γ|≦３０°の関係を満たし、かつ上記噴孔の入口部の中心から上記キャビティの上記弁座軸心の軸心方向の高さをｈｃ、上記噴孔の径をｄとした時に、πｄ２/４≦ｈｃ≦１.５ｄの関係を満たすものである。
A fuel injection valve according to the present invention includes an injection hole plate having a plurality of injection holes, a valve seat having a valve seat part that forms a cavity together with the injection hole plate and has an end surface that expands toward the downstream side, and the valve A valve body having a tip valve portion that opens and closes the nozzle hole in contact with the seat surface of the seat seat portion; the valve body opens when the valve body moves downstream; and the tip valve portion serves as the nozzle hole plate. A fuel injection device of an outer valve-opening method in which the valve-opening operation is ended by contacting with
On the downstream side of the valve seat portion, an extended taper surface that continuously extends on the seat surface and has a different inclination angle is formed, and the tip valve portion is separated from and in contact with the seat surface. And a bottom part that contacts the nozzle hole plate at the end of valve opening, and the inlet part of the nozzle hole is radially outward of the valve seat axis of the valve seat from the outermost peripheral edge part of the tip valve part. And the center of the inlet part of the nozzle hole is arranged inside an imaginary circle formed in the nozzle hole plate by intersecting the line extending downstream of the seat surface and the nozzle hole plate. And the center of the outlet part of the nozzle hole is arranged radially outside the valve seat axis with respect to the center of the inlet part of the nozzle hole, and the seat of the valve seat axis and the valve seat part The narrow angle formed by the surface is α (≦ 90 °), and the narrow angle formed by the valve seat axis and the extended tapered surface When the angle is β (≦ 90 °), and the nozzle hole angle formed by the thickness direction of the nozzle plate and the axis of the nozzle hole is γ, | α−β | ≦ 20 ° and | α−γ | When satisfying the relationship of ≦ 30 ° and the height of the axial center of the valve seat axis of the cavity from the center of the inlet of the nozzle hole is hc and the diameter of the nozzle hole is d, πd 2 / 4 ≦ hc ≦ 1.5d is satisfied.
この発明に係る燃料噴射弁によれば、燃料シート部から噴孔出口部に至るまでの流路内の燃料流れの急変や剥離の抑制により、流路内での圧力損失が低減し、噴孔出口部における燃料速度が高い状態で噴射され、燃料と空気との相対速度が増大し、空気が燃料液滴を分裂させるせん断力が増すことで燃料噴霧の微粒化が促進される。
また同時に、前記キャビティ内における減圧沸騰が抑制され、減圧沸騰による燃料内の気泡の発生が抑制され、温度や雰囲気変化に伴う流量特性（静的流量、動的流量）の変化を抑制することができる。
また、前記キャビティ体積を小さく設定できることから、負圧雰囲気への噴射時に、閉弁完了後に前記キャビティ内の燃料の一部が負圧によって噴孔からエンジン吸気管に吸い出され流量変化（動的流量）が大きくなる問題や、キャビティ内より吸い出された燃料の流速が小さいために閉弁直後に粒径が粗悪な燃料噴霧が噴射されてしまう問題は解消される。
According to the fuel injection valve according to the present invention, the pressure loss in the flow path is reduced by suppressing the sudden change and separation of the fuel flow in the flow path from the fuel seat portion to the injection hole outlet portion, and the injection hole The fuel is injected at a high fuel velocity at the outlet, the relative velocity between the fuel and air is increased, and the shear force that causes the air to break up the fuel droplets is increased, thereby promoting atomization of the fuel spray.
At the same time, reduced-pressure boiling in the cavity is suppressed, generation of bubbles in the fuel due to reduced-pressure boiling is suppressed, and changes in flow characteristics (static flow rate, dynamic flow rate) due to changes in temperature and atmosphere can be suppressed. it can.
In addition, since the cavity volume can be set small, a part of the fuel in the cavity is sucked out from the nozzle hole into the engine intake pipe by the negative pressure after the valve closing is completed when injecting into the negative pressure atmosphere. The problem that the flow rate) becomes large and the problem that the fuel spray with a coarse particle diameter is injected immediately after the valve closing because the flow rate of the fuel sucked out from the cavity is small are solved.
以下、図面に基づいて、この発明の各実施の形態を説明する。
なお、各図間において、同一符号は同一あるいは相当部分を示す。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, the same code | symbol shows the same or an equivalent part between each figure.
実施の形態１．
実施の形態１における燃料噴射弁は、弁座が下流側へ拡径するシート面を有し、弁座を開閉するため少なくともシート面が下流側へ拡径する弁体を有し、開弁の際には、弁体が下流側に移動し、弁体先端部と噴孔プレート上流面が当接することで開弁が終了する外開弁方式の構造をとり、また制御装置より動作信号を受けて弁体を動作させることで、燃料が、弁体と弁座のすきまを通って、弁座下流側に装着された噴孔プレートと弁体先端と弁座で囲まれたキャビティを通った後、前記噴孔プレートに複数設けられた噴孔から噴射されるタイプのものである。
以下、図１〜６に基づいて実施の形態１にかかる燃料噴射弁を説明する。
Embodiment 1 FIG.
The fuel injection valve according to the first embodiment has a seat surface whose diameter increases toward the downstream side, and a valve body whose diameter increases at least toward the downstream side in order to open and close the valve seat. In this case, the valve body moves to the downstream side, and the valve opening is terminated when the valve body tip and the upstream surface of the nozzle hole plate abut, and an operation signal is received from the control device. By operating the valve body, the fuel passes through the gap between the valve body and the valve seat, and then passes through the nozzle hole plate mounted on the downstream side of the valve seat, the tip of the valve body, and the cavity surrounded by the valve seat. The type is a type that is ejected from a plurality of nozzle holes provided in the nozzle hole plate.
Hereinafter, the fuel injection valve concerning Embodiment 1 is demonstrated based on FIGS.
図１において、１は燃料噴射弁を示しており、２はソレノイド装置、３は磁気回路のヨーク部分であるハウジング、５はコイル、６は磁気回路の可動鉄心部分であるアマチュア、７は弁装置であり、弁装置７は弁体８と弁本体９と弁座１０で構成されている。また、弁座１０は磁気回路の固定鉄心の役割も果たしている。
弁本体９は、チューブ１１の外径部に圧入後、溶接されている。弁体８及びスリーブ４は、アマチュア６に圧入後、溶接されている。また、スプリング受け１６はチューブ１１に圧入されている。弁座１０には、噴孔プレート１５が溶接部１５aで結合されている。
噴孔プレート１５は、図２に示されるように、板厚方向に貫通し、燃料噴射弁１の軸心から離れる方向に所定角度傾斜している複数の噴孔１２が設けられている。
詳細は後述（００１７〜００２０）するが、弁座１０の弁座シート部１０ａは、弁座軸心１０ｓに対する傾斜角を異にする連続した２面、すなわち上流側のシート面１０ａ１とこのシート面１０ａ１に連続して延在し且つ傾斜角を異にする延在部、すなわち延長テーパ面１０ａ２とで構成されている。又、弁体８は、弁座シート部１０ａのシート面１０ａ１と離接して噴孔１２を開閉する先端弁部８ａを有し、この先端弁部８ａは、シート面１０ａ１と離接するドーム状の弁体シート部８ａ１と、開弁終了時に噴孔プレート１５に当接する略平面状の底部８ａ２とで構成されている。
In FIG. 1, 1 indicates a fuel injection valve, 2 is a solenoid device, 3 is a housing which is a yoke portion of a magnetic circuit, 5 is a coil, 6 is an amateur which is a movable core portion of the magnetic circuit, and 7 is a valve device. The valve device 7 includes a valve body 8, a valve body 9, and a valve seat 10. The valve seat 10 also serves as a fixed iron core of the magnetic circuit.
The valve body 9 is welded after being press-fitted into the outer diameter portion of the tube 11. The valve body 8 and the sleeve 4 are welded after being press-fitted into the armature 6. The spring receiver 16 is press-fitted into the tube 11. A nozzle hole plate 15 is joined to the valve seat 10 by a welded portion 15a.
As shown in FIG. 2, the nozzle hole plate 15 is provided with a plurality of nozzle holes 12 that penetrate through the plate thickness direction and are inclined at a predetermined angle in a direction away from the axis of the fuel injection valve 1.
Although details will be described later (0017 to 0020), the valve seat portion 10a of the valve seat 10 has two continuous surfaces with different inclination angles with respect to the valve seat axis 10s, that is, the upstream seat surface 10a1 and the seat surface. It is comprised by the extension part which extends continuously to 10a1 and makes the inclination-angle different, ie, extended taper surface 10a2. Further, the valve body 8 has a tip valve portion 8a that opens and closes the injection hole 12 by being separated from and contacting the seat surface 10a1 of the valve seat portion 10a. The valve body sheet portion 8a1 and a substantially flat bottom portion 8a2 that comes into contact with the nozzle hole plate 15 at the end of the valve opening.
次に、図１〜３によって燃料噴射弁の開閉動作について説明する。なお、図２は閉弁状態、図３は開弁状態を示している。
内燃機関の制御装置より燃料噴射弁１の駆動回路に動作信号が送られると、燃料噴射弁１のコイル５に電流が通電され、アマチュア６、弁座１０、弁本体９、ハウジング３、チューブ１１で構成される磁気回路に磁束が発生し、アマチュア６が弁座１０にひきつけられる。これにより、アマチュア６、及びスリーブ４と一体となった弁体８の弁体シート部８ａ１が、弁座シート部１０ａのシート面１０ａ１から離れて下流側に移動し、燃料は、弁座１０の内径部１０bと弁体８の隙間、及び弁体８のガイド部８ｂに設けられた平面部８ｃと内径部１０bの間の隙間を通り、弁座シート部１０ａを通って噴孔１２よりエンジン吸気管（図示せず）へ噴射される。弁体８の移動は図３に示すように、先端弁部８ａの底部８ａ２が噴孔プレート１５上流側端面に当接することで終了する。
Next, the opening / closing operation of the fuel injection valve will be described with reference to FIGS. 2 shows a valve closed state, and FIG. 3 shows a valve opened state.
When an operation signal is sent from the control device of the internal combustion engine to the drive circuit of the fuel injection valve 1, a current is passed through the coil 5 of the fuel injection valve 1, and the armature 6, the valve seat 10, the valve main body 9, the housing 3, and the tube 11. Magnetic flux is generated in the magnetic circuit configured by the following, and the armature 6 is attracted to the valve seat 10. Thereby, the valve body seat portion 8a1 of the valve body 8 integrated with the armature 6 and the sleeve 4 moves away from the seat surface 10a1 of the valve seat portion 10a to the downstream side, and the fuel The engine intake air passes through the clearance between the inner diameter portion 10b and the valve body 8, and the clearance between the flat surface portion 8c provided on the guide portion 8b of the valve body 8 and the inner diameter portion 10b, and passes through the valve seat sheet portion 10a. It is injected into a tube (not shown). As shown in FIG. 3, the movement of the valve body 8 ends when the bottom portion 8 a 2 of the tip valve portion 8 a contacts the upstream end surface of the nozzle hole plate 15.
内燃機関の制御装置より燃料噴射弁１の駆動回路に動作の停止信号が送られると、コイル５への通電を停止し、磁気回路中の磁束が減少して弁体８を閉弁方向に押しているスプリング１３により、弁体８が上流側へ移動することで弁座シート部１０ａ間の隙間は閉じて燃料噴射は終了する。閉弁時には弁座１０と噴孔プレート１５、および弁体８で囲まれるキャビティ１４が形成される。 When an operation stop signal is sent from the control device of the internal combustion engine to the drive circuit of the fuel injection valve 1, the energization to the coil 5 is stopped, the magnetic flux in the magnetic circuit is reduced, and the valve body 8 is pushed in the valve closing direction. When the valve body 8 is moved upstream by the spring 13, the gap between the valve seat portions 10a is closed and the fuel injection is completed. When the valve is closed, a cavity 14 surrounded by the valve seat 10, the injection hole plate 15, and the valve body 8 is formed.
次に、図４によって噴孔プレート１５部の構成を詳細に説明する。
噴孔入口部１２ａは、先端弁部８ａの最外周縁部８ａａより外側、すなわち噴孔プレート１５の上流面に弁座軸心方向に投影した形状輪郭より、弁座軸心１０ｓの径方向外側に配置されており、かつ噴孔入口部１２ａの中心は、弁座シート部１０ａのシート面１０ａ１の下流側への延長線（Ｃ１−Ｃ２）と噴孔プレート１５が交差（Ｃ）することにより噴孔プレート１５の上流側端面に形成される仮想円の内側に配置されており、かつ噴孔出口部１２ｂの中心は、噴孔入口部１２ａの中心に対して弁座軸心１０ｓの径方向外側に配置されている。なお、Ｌ１は先端弁部８ａの半径、Ｌ２は配列された噴孔１２と弁座軸心１０ｓ間の距離である。
Next, the structure of the nozzle hole plate 15 will be described in detail with reference to FIG.
The nozzle hole inlet portion 12a is radially outward of the valve seat shaft center 10s from the outer shape of the outermost peripheral edge portion 8aa of the tip valve portion 8a, that is, from the shape contour projected onto the upstream surface of the nozzle hole plate 15 in the valve seat shaft direction. And the center of the injection hole inlet portion 12a intersects (C) the line (C 1 -C 2 ) extending downstream of the seat surface 10a1 of the valve seat portion 10a and the injection hole plate 15. Accordingly, the center of the nozzle hole outlet portion 12b is located at the center of the nozzle hole inlet portion 12a with respect to the center of the nozzle hole inlet portion 12a. Arranged radially outside. L1 is the radius of the tip valve portion 8a, and L2 is the distance between the arranged nozzle holes 12 and the valve seat axis 10s.
更に、弁座軸心１０ｓとシート面１０ａ１がなす角の狭角をα（≦９０°）、延長テーパ面１０ａ２と弁座軸心１０ｓのなす角の狭角をβ（≦９０°）、噴孔プレート板厚方向の軸１２ｓと噴孔１２の軸心１２cがなす噴孔角をγとした時に、|α−β|≦２０°、かつ|α−γ|≦３０°を満たし、かつ噴孔入口部１２ａの中心からキャビティ１４内の弁座軸心１０ｓの軸心方向の高さをｈｃ、噴孔１２の径をｄとした時に、πｄ２/４≦ｈｃ≦１.５ｄの関係を満たすことを特徴としている。 Furthermore, the narrow angle formed by the valve seat axis 10s and the seat surface 10a1 is α (≦ 90 °), and the narrow angle formed by the extended tapered surface 10a2 and the valve seat axis 10s is β (≦ 90 °). When the nozzle hole angle formed by the axis 12s in the hole plate thickness direction and the axis 12c of the nozzle hole 12 is γ, | α−β | ≦ 20 ° and | α−γ | ≦ 30 ° are satisfied and When the height in the axial direction of the valve seat axis 10s in the cavity 14 from the center of the hole inlet portion 12a is hc and the diameter of the injection hole 12 is d, the relationship of πd 2 /4≦hc≦1.5d is established. It is characterized by satisfying.
前記の噴孔配置や、前記α、β、γの関係により、燃料シート部から噴孔出口部１２ｂに至るまでの流路内の燃料流れの急変や剥離が抑制され、流路内での圧力損失が低減し、噴孔出口部における燃料速度が高い状態で噴射され、燃料と空気との相対速度が増大し、空気が燃料液滴を分裂させるせん断力が増すことで燃料噴霧の微粒化が促進される。 Due to the arrangement of the nozzle holes and the relationship between α, β, and γ, sudden change or separation of the fuel flow in the flow path from the fuel seat portion to the nozzle hole outlet portion 12b is suppressed, and the pressure in the flow passage is reduced. Loss is reduced, fuel is injected at a high fuel velocity at the nozzle outlet, the relative velocity between the fuel and air is increased, and the shear force that causes the air to break up the fuel droplets increases, resulting in atomization of the fuel spray. Promoted.
図５は、α−β、α−γと粒径の関係を実験により求めた結果を示す図である。
この図５によって、|α−β|≦２０°、かつ|α−γ|≦３０°を満たすことで微粒化改善効果が得られていることが確認できる。
また同時に、キャビティ１４内における減圧沸騰が抑制され、減圧沸騰による燃料内の気泡の発生が抑制され、温度や雰囲気変化に伴う流量特性（静的流量、動的流量）の変化を抑制することができる。
また、πｄ２/４（Ｓ１）≦ｄ＊ｈｃ（Ｓ２）により、噴孔入口部面積≦噴孔直上部の燃料通過面積となり、噴孔直上部での絞り部形成による圧力損失を抑制することが出来る。
同時に、ｈｃ≦１.５ｄを満たすことで、キャビティ１４の体積を一定以下に抑えることができ、負圧雰囲気への噴射時に、閉弁完了後に前記キャビティ内の燃料の一部が負圧によって噴孔からエンジン吸気管に吸い出され流量変化（動的流量）が大きくなる問題や、キャビティ内より吸い出された燃料の流速が小さいために閉弁直後に粒径が粗悪な燃料噴霧が噴射されてしまう問題が解消される。
また、先端弁部８ａと噴孔プレート１５上流側平面が当接する構成にすることで、当接しない場合に対してよりキャビティ部の体積を小さく構成可能である。
FIG. 5 is a diagram showing the results of experiments on the relationship between α-β, α-γ and particle size.
It can be confirmed from FIG. 5 that the effect of improving the atomization is obtained by satisfying | α−β | ≦ 20 ° and | α−γ | ≦ 30 °.
At the same time, reduced-pressure boiling in the cavity 14 is suppressed, generation of bubbles in the fuel due to reduced-pressure boiling is suppressed, and changes in flow rate characteristics (static flow rate, dynamic flow rate) due to changes in temperature and atmosphere can be suppressed. it can.
Further, by πd 2/4 (S 1) ≦ d * hc (S 2), becomes a fuel passage area of the injection hole inlet area ≦ injection hole immediately above, suppressing the pressure loss by the throttle section formed in the injection hole immediately above I can do it.
At the same time, by satisfying hc ≦ 1.5d, the volume of the cavity 14 can be kept below a certain level, and when injecting into the negative pressure atmosphere, a part of the fuel in the cavity is injected by the negative pressure after the valve closing is completed. The problem is that the change in flow rate (dynamic flow rate) is increased by being sucked into the engine intake pipe from the hole, and the fuel spray with a poor particle size is injected immediately after the valve is closed because the flow rate of the fuel sucked out from the cavity is small. This will eliminate the problem.
In addition, by adopting a configuration in which the tip valve portion 8a and the upstream surface of the nozzle hole plate 15 are in contact with each other, the volume of the cavity portion can be made smaller than in the case where they do not contact.
さらに、この実施の形態１における弁体８は、先端弁部８ａの形状全体をＲ形状（ボールの一部）とするのではなく、その一部をＲ形状としたドーム状の形状にしている。これは、下記の理由による。
一般的に、燃料噴射弁は、所定の噴射流量を確保するためにシート部で一定の燃料通過面積を確保する必要があり、燃料通過面積は、主にシート径及び弁体８の軸心方向へのリフト量によって決定される。
図６（a）に示すように、先端弁部８ａの全体がＲ形状となっている場合は、燃料通過面積を所定量確保するために、ある程度の大きさのボール径を設定し一定の大きさのシート径を確保する必要がある。しかし、ボール径を大きく設定し、諸般の理由によりシート角を拡大する必要がある場合、シート径が必要以上に小さくなってしまい、結果的に必要流量が確保できなくなる問題がある。
Furthermore, the valve body 8 according to the first embodiment is not formed into an R shape (a part of the ball) as the entire shape of the tip valve portion 8a, but is formed into a dome shape having a part of the R shape. . This is due to the following reason.
In general, the fuel injection valve needs to ensure a certain fuel passage area in the seat portion in order to ensure a predetermined injection flow rate. The fuel passage area mainly includes the seat diameter and the axial direction of the valve body 8. Is determined by the amount of lift.
As shown in FIG. 6 (a), when the entire tip valve portion 8a has an R shape, a ball diameter of a certain size is set to a certain size in order to secure a predetermined amount of fuel passage area. It is necessary to ensure the sheet diameter. However, when the ball diameter is set large and the seat angle needs to be enlarged for various reasons, the seat diameter becomes unnecessarily small, resulting in a problem that the required flow rate cannot be secured.
また、その場合には、図６（ｂ）のようにシート径が小さく、かつシート角が大きくなっており、従って前記キャビティ部の体積が大きくなってしまう。これにより、前記の流量変化（動的流量）の増大や、微粒化の悪化の問題が発生する。
そこで、この実施の形態１においては、先端弁部８ａをボール形状とするのではなく、図６（ｃ）に示すように先端弁部８ａの一部をＲ形状とすることで、シート角を変更した際のシート径の変化が小さくなるように設定することが可能となる。（図６（ｄ）参照）
In this case, as shown in FIG. 6B, the sheet diameter is small and the sheet angle is large, so that the volume of the cavity portion is large. Thereby, the problem of the increase of the said flow volume change (dynamic flow volume) and the deterioration of atomization generate | occur | produces.
Therefore, in the first embodiment, the front end valve portion 8a is not formed into a ball shape, but a part of the front end valve portion 8a is formed into an R shape as shown in FIG. It is possible to set so that the change in the sheet diameter when changing is small. (See Fig. 6 (d))
従って、この実施の形態１においては、燃料通路面積を確保しつつシート角を自由に設定可能であり、かつキャビティ１４の体積を小さく保つことが可能である。
なお、シート部における燃料通過面積を確保するために、弁体８のリフト量を増加させる手法については、弁体８と固定鉄心のエアギャップが増加することで弁体８の動作性が悪化する問題点があるため、極力用いない。
この実施の形態１において、図１〜１５で示す弁体の先端弁部８ａの形状は、円錐形となっているが、傘状以外の形状についてもこの発明の要旨を逸脱しない範囲で変更可能とする。
Therefore, in the first embodiment, the seat angle can be freely set while ensuring the fuel passage area, and the volume of the cavity 14 can be kept small.
In addition, about the method of increasing the lift amount of the valve body 8 in order to ensure the fuel passage area in a seat part, the operativity of the valve body 8 deteriorates because the air gap of the valve body 8 and a fixed iron core increases. Because there is a problem, do not use as much as possible.
In the first embodiment, the shape of the tip valve portion 8a of the valve body shown in FIGS. 1 to 15 is a conical shape, but shapes other than the umbrella shape can be changed without departing from the gist of the present invention. And
実施の形態２．
図７に基づいて実施の形態２にかかる燃料噴射弁を説明する。
図７は、燃料噴射弁の開弁状態を示しており、この実施の形態２では、噴孔プレート１５の上流面上の、先端弁部８ａの底部８ａ２との対向位置に、弁座軸心１０ｓの上流側へ突出する凸部１５ｄを有し、開弁の際には、先端弁部８ａの底部８ａ２と凸部１５ｄが当接することで開弁が終了する。
凸部１５ｄを設けることで、開弁時の弁体８と噴孔プレート１５の当接面積が小さくなり、従って凸部１５ｄが無い場合に対して閉弁時に弁体８を噴孔プレート１５から引き離すのに必要なエネルギーが少なくて済むことから、閉弁時の弁体移動時間を短縮することが出来る。
Embodiment 2. FIG.
A fuel injection valve according to the second embodiment will be described based on FIG.
FIG. 7 shows the opened state of the fuel injection valve. In the second embodiment, the valve seat axis is located on the upstream surface of the nozzle hole plate 15 at a position facing the bottom 8a2 of the tip valve portion 8a. It has the convex part 15d which protrudes to the upstream of 10s, and at the time of valve opening, valve | bulb opening is complete | finished when the bottom part 8a2 and the convex part 15d of the front-end | tip valve part 8a contact | abut.
By providing the convex portion 15d, the contact area between the valve body 8 and the nozzle hole plate 15 at the time of opening the valve is reduced. Since less energy is required to separate the valve body, the time required for moving the valve body when the valve is closed can be shortened.
この実施の形態２では、噴孔プレート１５上の凸部１５ｄが噴孔プレート１５と一体に形成されているが、それに限ったものではなく、凸部を形成する部分とその他の部分は別体であっても上記と同様の効果が得られる。なお、この実施の形態２において凸部を設けた理由は、弁体８と噴孔プレート１５の接触面積を小さくすることであるから、凸部に限らず、プレート上流側端面の弁体８との接触面に溝などを設けた場合についても上記と同様の効果が得られる。 In the second embodiment, the convex portion 15d on the nozzle hole plate 15 is formed integrally with the nozzle hole plate 15. However, the present invention is not limited to this, and the part forming the convex part and the other part are separate. However, the same effect as described above can be obtained. In addition, since the reason which provided the convex part in this Embodiment 2 is making the contact area of the valve body 8 and the nozzle hole plate 15 small, not only a convex part but the valve body 8 of a plate upstream end surface and The same effect as described above can be obtained when a groove or the like is provided on the contact surface.
実施の形態３．
図８に基づいて実施の形態３にかかる燃料噴射弁を説明する。
この実施の形態３の燃料噴射弁は、実施の形態２の変形例である。
この実施の形態２では、先端弁部８ａの底部８ａ２に凸部８ｄを有しており、開弁の際には、この凸部８ｄが噴孔プレート１５の上流面と当接することで開弁が終了し、実施の形態２と同様の効果が得られる。
Embodiment 3 FIG.
A fuel injection valve according to the third embodiment will be described based on FIG.
The fuel injection valve of the third embodiment is a modification of the second embodiment.
In the second embodiment, the bottom 8a2 of the tip valve portion 8a has a convex portion 8d. When the valve is opened, the convex portion 8d abuts on the upstream surface of the nozzle hole plate 15 to open the valve. Is completed, and the same effect as in the second embodiment can be obtained.
実施の形態４．
図９〜１２に基づいて実施の形態４にかかる燃料噴射弁を説明する。
まず、図９の燃料噴射弁について説明する。図１０〜１２は、図９の変形例である。
この実施の形態４の燃料噴射弁は、噴孔プレート１５の上流面上に、先端弁部８ａの底部８ａ２との対向位置に、弁座軸心１０ｓの上流側へ突出する凸部１５ｅを有し、先端弁部８ａの底部８ａ２には、凸部１５ｅと嵌め合う凹部８ｅを有し、摺動部を構成している。
このように構成することによって、リフト開弁（リフト動作）時には、噴孔プレート１５の凸部１５ｅが弁体８の凹部８ｅをガイドする役目を果たしている。更に、弁体８と噴孔１２の位置バラツキ低減の役割を果たすことにより、シート部から各噴孔１２までの距離のバラツキが小さくなり、各噴孔からの単噴霧間の微粒化レベルのバラツキが小さくなる。更に、微粒化レベルのバラツキが小さくなることから、各噴孔からの噴霧によって形成される集合噴霧内の均一性が増し、燃焼性が向上し、従って燃費向上に有効と言える。
凸部１５ｅの形状については、図９のような形状に限ったものではなく、図１１、図１２のように、テーパ状の凹凸部８ｇ、１５ｇである場合や、球状の凹凸部８ｈ、１５ｈにした場合でも上記と同様の効果が得られる。
なお、この実施の形態４では、噴孔プレート１５側に凸部、弁体８側に凹部を有していたが、図１０に示すように噴孔プレート１５側に凹部１５ｆ、弁体８側に凸部８ｆを設けた場合でも上記と同様の効果が得られる。
Embodiment 4 FIG.
A fuel injection valve according to the fourth embodiment will be described with reference to FIGS.
First, the fuel injection valve in FIG. 9 will be described. 10 to 12 are modifications of FIG.
The fuel injection valve according to the fourth embodiment has a convex portion 15e protruding on the upstream side of the valve seat axis 10s on the upstream surface of the nozzle hole plate 15 at a position facing the bottom portion 8a2 of the tip valve portion 8a. The bottom portion 8a2 of the tip valve portion 8a has a concave portion 8e that fits with the convex portion 15e, and constitutes a sliding portion.
With this configuration, the convex portion 15e of the nozzle hole plate 15 serves to guide the concave portion 8e of the valve body 8 when the valve is opened (lifting operation). Further, by playing the role of reducing the positional variation between the valve body 8 and the nozzle hole 12, the variation in the distance from the seat portion to each nozzle hole 12 is reduced, and the variation in atomization level between single sprays from each nozzle hole is reduced. Becomes smaller. Further, since the variation in the atomization level is reduced, the uniformity in the collective spray formed by the spray from each nozzle hole is increased, and the combustibility is improved.
The shape of the convex portion 15e is not limited to the shape shown in FIG. 9, but may be tapered uneven portions 8g and 15g as shown in FIGS. 11 and 12, or spherical uneven portions 8h and 15h. Even in this case, the same effect as described above can be obtained.
In the fourth embodiment, the projection is provided on the injection hole plate 15 side and the depression is provided on the valve body 8 side. However, as shown in FIG. 10, the depression 15f is provided on the injection hole plate 15 side and the valve element 8 side is provided. Even in the case where the convex portion 8f is provided, the same effect as described above can be obtained.
実施の形態５．
図１３に基づいて実施の形態５にかかる燃料噴射弁を説明する。
図１３に示した実施の形態５の燃料噴射装置は、噴孔１２の孔長が、弁座軸心１０ｓに対して径方向内側の噴孔長さよりも径方向外側の噴孔長さが短くなるように設定されている。そして、このような構成にするため、噴孔出口部１２ｂの一部、すなわち弁座軸心１０ｓの径方向外側に、プレス成形による凹部（くぼみ部）１２ｆが設られている。なお、この凹部１２ｆの底面は、噴孔出口部１２ｂの周縁部の少なくとも一部分を開口した形状であり、噴孔出口部１２ｂの他の部分は、噴孔プレート１５の下流側端面に開口、もしくは凹部１２ｆの内面に接しているように形成されている。又、噴孔１２内の流路において、噴孔入口部１２ａから凹部１２ｆまでの間に最小断面積となる円柱部分が確保されることにより、インジェクタの個体ごとの流量のバラツキを抑制している。
又、このように構成することで、弁座軸心１０ｓに対して径方向内側に噴孔部が確保され、燃料噴射の指向性を犠牲にすることなく、噴孔長さが短く形成された径方向外側の噴孔により噴孔内部での圧力損失を低減させることが可能であり、これにより、噴孔出口部１２ｂにおける燃料速度が高い状態で噴射され、燃料と空気との相対速度が増大し、空気が燃料液滴を分裂させるせん断力が増すことで噴射された燃料噴霧の微粒化が促進される。
Embodiment 5 FIG.
A fuel injection valve according to Embodiment 5 will be described with reference to FIG.
In the fuel injection device of Embodiment 5 shown in FIG. 13, the hole length of the injection hole 12 is shorter than the injection hole length on the radial inner side with respect to the valve seat axis 10s. It is set to be. And in order to set it as such a structure, the recessed part (recessed part) 12f by press molding is provided in a part of nozzle hole exit part 12b, ie, the radial direction outer side of the valve-seat axial center 10s. The bottom surface of the recess 12f has a shape in which at least a part of the peripheral edge of the nozzle hole outlet part 12b is opened, and the other part of the nozzle hole outlet part 12b is opened on the downstream end face of the nozzle hole plate 15, or It is formed so as to be in contact with the inner surface of the recess 12f. Further, in the flow path in the injection hole 12, a cylindrical portion having a minimum cross-sectional area is secured between the injection hole inlet portion 12a and the recess 12f, thereby suppressing the variation in flow rate for each injector. .
Further, with this configuration, the nozzle hole portion is secured radially inward with respect to the valve seat axis 10s, and the nozzle hole length is reduced without sacrificing the directivity of fuel injection. It is possible to reduce the pressure loss inside the nozzle hole by the radially outer nozzle hole, whereby the fuel is injected at a high fuel velocity at the nozzle hole outlet portion 12b, and the relative velocity between the fuel and air increases. However, the atomization of the injected fuel spray is promoted by increasing the shearing force that causes the air to break up the fuel droplets.
実施の形態６．
図１４に基づいて実施の形態６にかかる燃料噴射弁を説明する。
なお、図１４（ａ）は燃料噴射弁の開弁状態を示す断面図、（ｂ）は噴孔１２における燃料の流れを説明するための説明図である。
噴孔部のプレス成形の際には、抜き方向を弁座軸心１０ｓの上流側から下流側とすることで、噴孔入口部１２ａには、抜き角度に応じたダレ１２ｇが形成され、噴孔出口部１２ｂにはバリが形成される。
前記の通り噴孔出口部１２ｂは、弁座軸心１０ｓに対して噴孔入口部１２ａの外側に配置されているため、噴孔１２の入口縁部のダレ１２ｇは、主に弁座軸心１０ｓに対して内側に形成される。
このダレ１２ｇの形成により、図１４（ｂ）に示すように弁座軸心１０ｓの内側から外側に向かう燃料流れの、噴孔入口部１２ａにおける剥離が抑制され、弁座軸心１０ｓの内側から外側に向かう流れ（矢印ア参照）が強化されることで、噴孔出口部１２ｂから噴射された後の燃料噴霧の拡がり（イ参照）が強化され、従って燃料噴霧の微粒化が促進される。なお、図１４（ｂ）において、（ウ）は噴孔入口部１２ａにダレ面が形成された場合の燃料噴霧稜線を示し、（エ）は噴孔入口部１２ａにダレ無しの場合の燃料噴霧稜線を示したものであり、これによっても噴孔出口部１２ｂから噴射された後の燃料噴霧の拡がりが、強化されていることが判る。
Embodiment 6 FIG.
A fuel injection valve according to Embodiment 6 will be described based on FIG.
14A is a cross-sectional view showing the opened state of the fuel injection valve, and FIG. 14B is an explanatory view for explaining the flow of fuel in the nozzle hole 12.
When the injection hole portion is press-molded, the drawing direction is changed from the upstream side to the downstream side of the valve seat axis 10s, so that a droop 12g corresponding to the drawing angle is formed at the injection hole inlet portion 12a. A burr is formed at the hole outlet 12b.
As described above, the nozzle hole outlet portion 12b is disposed outside the nozzle hole inlet portion 12a with respect to the valve seat axis 10s, so that the sag 12g at the inlet edge of the nozzle hole 12 is mainly the valve seat axis. It is formed inside for 10s.
By forming this sag 12g, as shown in FIG. 14B, separation of the fuel flow from the inner side to the outer side of the valve seat axis 10s at the injection hole inlet portion 12a is suppressed, and from the inner side of the valve seat axis 10s. As the flow toward the outside (see arrow A) is strengthened, the spread (see b) of the fuel spray after being injected from the nozzle hole outlet portion 12b is strengthened, and thus atomization of the fuel spray is promoted. In FIG. 14B, (c) shows a fuel spray ridge line when a sag surface is formed at the injection hole inlet 12a, and (d) shows a fuel mist when there is no sag at the injection hole inlet 12a. The ridge line is shown, and it can be seen that the spread of the fuel spray after being injected from the nozzle hole outlet portion 12b is also strengthened.
実施の形態７．
図１５に基づいて実施の形態７にかかる燃料噴射弁を説明する。
図１５は、この発明の実施の形態７における燃料噴射弁の開弁状態を示し、（ａ）は要部を拡大して示した断面図、（ｂ）は図（ａ）中の矢印Ｙ方向から見た平面図である。
噴孔出口部１２ｂに形成する凹部１２ｆをプレス成形で加工することで、噴孔プレート１５の上流側平面に位置する噴孔入口部１２ａ付近にハラミ１５ｇが形成される。
このハラミ１５ｇは、噴孔入口部１２ａと噴孔出口部１２ｂと凹部１２ｆの位置関係から、弁座軸心１０ｓに対して径方向外側の部分に多く形成される。
このように噴孔入口部１２ａ周辺にハラミ１５ｇが存在することによって、弁座軸心１０ｓから直接噴孔１２に流入せずに一旦外周側に衝突しＵターンして噴孔１２に返ってくる燃料は、流れ（矢印カ参照）が弱まり、そのため弁座軸心１０ｓから直接噴孔１２に流入する流れ（矢印オ参照）が相対的に強化され、従ってより噴孔出口部１２ｂにおける燃料速度が高い状態で燃料が噴射されることから、噴霧の微粒化が促進される。
Embodiment 7 FIG.
A fuel injection valve according to Embodiment 7 will be described based on FIG.
15 shows the opened state of the fuel injection valve according to Embodiment 7 of the present invention, (a) is an enlarged cross-sectional view showing the main part, and (b) is the direction of arrow Y in FIG. (A). It is the top view seen from.
By processing the concave portion 12f formed in the nozzle hole outlet portion 12b by press molding, a sag 15g is formed in the vicinity of the nozzle hole inlet portion 12a located on the upstream plane of the nozzle hole plate 15.
Due to the positional relationship among the injection hole inlet portion 12a, the injection hole outlet portion 12b, and the recess 12f, a large amount of this harami 15g is formed in the radially outer portion with respect to the valve seat axis 10s.
As a result of the presence of the stagnation 15g around the nozzle hole inlet 12a in this way, it does not flow directly from the valve seat axis 10s into the nozzle hole 12, but once collides with the outer peripheral side and makes a U-turn and returns to the nozzle hole 12. The flow of the fuel (see arrow カ) is weakened. Therefore, the flow (see arrow オ) flowing directly from the valve seat axis 10s directly into the nozzle hole 12 is relatively strengthened, so that the fuel velocity at the nozzle hole outlet portion 12b is further increased. Since the fuel is injected in a high state, atomization of the spray is promoted.
なお、この発明は、上記実施の形態１〜７に限定されるものではなく、その要旨を逸脱しない範囲で種々の設計変更が可能である。
なお又、この発明は、その発明の範囲内において、各実施の形態を適宜、変形、省略することが可能である。
In addition, this invention is not limited to the said Embodiment 1-7, A various design change is possible in the range which does not deviate from the summary.
In the present invention, each embodiment can be appropriately modified or omitted within the scope of the invention.
１：燃料噴射弁、２：ソレノイド装置、３：ハウジング、４：スリーブ、
５：コイル、６：アマチュア、７：弁装置、８：弁体、８a：先端弁部、
８ａ１：ドーム状の弁体シート部、８ａ２：底部、８ａａ：先端弁部の外周縁部、
８ｂ：ガイド部、８ｃ：平面部、８ｄ：凸部、８ｅ：凹部、９：弁本体、
１０：弁座、 ０ｓ：弁座軸心、１０ａ：弁座シート部、１０ａ１：シート面、
１０ａ２：延長テーパ面、１０b：内径部、１１：チューブ、１２：噴孔、
１２ａ：噴孔入口部、１２ｂ：噴孔出口部、１２ｃ：噴孔入口部の軸心、
１２ｆ：凹部（くぼみ部）、１２ｇ：ダレ、１３：スプリング、１４：キャビティ、
１５：噴孔プレート、１５a：溶接部、１５ｄ：凸部、１５ｅ：凸部、
１５ｆ：凹部（くぼみ部）、１５ｇ：ハラミ、１６：スプリング受け。
1: fuel injection valve, 2: solenoid device, 3: housing, 4: sleeve,
5: coil, 6: amateur, 7: valve device, 8: valve body, 8a: tip valve part,
8a1: Domed valve body seat portion, 8a2: bottom portion, 8aa: outer peripheral edge portion of the tip valve portion,
8b: guide part, 8c: flat part, 8d: convex part, 8e: concave part, 9: valve body,
10: Valve seat, 0s: Valve seat axis, 10a: Valve seat portion, 10a1: Seat surface,
10a2: extended taper surface, 10b: inner diameter part, 11: tube, 12: injection hole,
12a: injection hole inlet part, 12b: injection hole outlet part, 12c: axial center of the injection hole inlet part,
12f: concave portion (recessed portion), 12g: sagging, 13: spring, 14: cavity,
15: injection hole plate, 15a: welded part, 15d: convex part, 15e: convex part,
15f: recessed part (recessed part), 15g: harami, 16: spring receiver.
この発明に係わる燃料噴射弁は、複数の噴孔を有する噴孔プレート、この噴孔プレートと共にキャビティを形成し端面が下流側に向かって拡径する弁座シート部を有する弁座、及び上記弁座シート部のシート面と離接して上記噴孔を開閉する先端弁部を有する弁体を備え、上記弁体が下流側へ移動することにより開弁すると共に上記先端弁部が上記噴孔プレートに当接することで開弁動作が終了する外開弁方式の燃料噴射装置であって、
上記弁座シート部の下流側には、上記シート面に連続して延在し且つ傾斜角を異にする延長テーパ面が形成され、上記先端弁部は、上記シート面と離接する弁体シート部と、開弁終了時に上記噴孔プレートに当接する底部とで形成され、上記噴孔の入口部は、上記先端弁部の最外周縁部より上記弁座の弁座軸心の径方向外側に配置されると共に上記噴孔の入口部の中心は、上記シート面の下流側への延長線と上記噴孔プレートが交差することにより上記噴孔プレートに形成される仮想円の内側に配置され、かつ上記噴孔の出口部の中心は、上記噴孔の入口部の中心に対して上記弁座軸心の径方向外側に配置され、かつ上記
弁座軸心と上記弁座シート部のシート面とがなす狭み角をα（≦９０°）、上記弁座軸心と上記延長テーパ面とがなす狭み角をβ（≦９０°）、上記噴孔プレートの板厚方向と上記噴孔の軸心がなす噴孔角をγとした時に、|α−β|≦２０°、かつ|α−γ|≦３０°の関係を満たし、かつ上記噴孔の入口部の中心から上記キャビティの上記弁座軸心の軸心方向の高さをｈｃ、上記噴孔の径をｄとした時に、πｄ ２ /４（Ｓ １ ）≦ｄ＊ｈｃ（Ｓ ２ ）、及びｈｃ≦１.５ｄの関係を満たすものである。
A fuel injection valve according to the present invention includes an injection hole plate having a plurality of injection holes, a valve seat having a valve seat part that forms a cavity together with the injection hole plate and has an end surface that expands toward the downstream side, and the valve A valve body having a tip valve portion that opens and closes the nozzle hole in contact with the seat surface of the seat seat portion; the valve body opens when the valve body moves downstream; and the tip valve portion serves as the nozzle hole plate. A fuel injection device of an outer valve-opening method in which the valve-opening operation is ended by contacting with
On the downstream side of the valve seat portion, an extended taper surface that continuously extends on the seat surface and has a different inclination angle is formed, and the tip valve portion is separated from and in contact with the seat surface. And a bottom part that contacts the nozzle hole plate at the end of valve opening, and the inlet part of the nozzle hole is radially outward of the valve seat axis of the valve seat from the outermost peripheral edge part of the tip valve part. And the center of the inlet part of the nozzle hole is arranged inside an imaginary circle formed in the nozzle hole plate by intersecting the line extending downstream of the seat surface and the nozzle hole plate. And the center of the outlet part of the nozzle hole is arranged radially outside the valve seat axis with respect to the center of the inlet part of the nozzle hole, and the seat of the valve seat axis and the valve seat part The narrow angle formed by the surface is α (≦ 90 °), and the narrow angle formed by the valve seat axis and the extended tapered surface When the angle is β (≦ 90 °), and the nozzle hole angle formed by the thickness direction of the nozzle plate and the axis of the nozzle hole is γ, | α−β | ≦ 20 ° and | α−γ | When satisfying the relationship of ≦ 30 ° and the height of the axial center of the valve seat axis of the cavity from the center of the inlet of the nozzle hole is hc and the diameter of the nozzle hole is d, πd 2 / 4 (S 1 ) ≦ d * hc (S 2 ) and hc ≦ 1.5d are satisfied.
更に、弁座軸心１０ｓとシート面１０ａ１がなす角の狭角をα（≦９０°）、延長テーパ面１０ａ２と弁座軸心１０ｓのなす角の狭角をβ（≦９０°）、噴孔プレート板厚方向の軸１２ｓと噴孔１２の軸心１２cがなす噴孔角をγとした時に、|α−β|≦２０°、かつ|α−γ|≦３０°を満たし、かつ噴孔入口部１２ａの中心からキャビティ１４内の弁座軸心１０ｓの軸心方向の高さをｈｃ、噴孔１２の径をｄとした時に、πｄ ２ /４（Ｓ １ ）≦ｄ＊ｈｃ（Ｓ ２ ）、同時に、ｈｃ≦１.５ｄの関係を満たすことを特徴としている（図４及び段落００２０参照）。 Furthermore, the narrow angle formed by the valve seat axis 10s and the seat surface 10a1 is α (≦ 90 °), and the narrow angle formed by the extended tapered surface 10a2 and the valve seat axis 10s is β (≦ 90 °). When the nozzle hole angle formed by the axis 12s in the hole plate thickness direction and the axis 12c of the nozzle hole 12 is γ, | α−β | ≦ 20 ° and | α−γ | ≦ 30 ° are satisfied and the axial direction of the height from the center of the valve seat axis 10s of the cavity 14 of the hole entry section 12a hc, the diameter of the injection hole 12 when the d, πd 2/4 (S 1) ≦ d * hc ( S 2 ) and simultaneously satisfy the relationship of hc ≦ 1.5d ( see FIG. 4 and paragraph 0020 ).
Claims (7)
上記弁座シート部の下流側には、上記シート面に連続して延在し且つ傾斜角を異にする延長テーパ面が形成され、上記先端弁部は、上記シート面と離接する弁体シート部と、開弁終了時に上記噴孔プレートに当接する底部とで形成され、上記噴孔の入口部は、上記先端弁部の最外周縁部より上記弁座の弁座軸心の径方向外側に配置されると共に上記噴孔の入口部の中心は、上記シート面の下流側への延長線と上記噴孔プレートが交差することにより上記噴孔プレートに形成される仮想円の内側に配置され、かつ上記噴孔の出口部の中心は、上記噴孔の入口部の中心に対して上記弁座軸心の径方向外側に配置され、かつ上記弁座軸心と上記弁座シート部のシート面とがなす狭み角をα（≦９０°）、上記弁座軸心と上記延長テーパ面とがなす狭み角をβ（≦９０°）、上記噴孔プレートの板厚方向と上記噴孔の軸心がなす噴孔角をγとした時に、|α−β|≦２０°、かつ|α−γ|≦３０°の関係を満たし、かつ上記噴孔の入口部の中心から上記キャビティの上記弁座軸心の軸心方向の高さをｈｃ、上記噴孔の径をｄとした時に、πｄ２/４≦ｈｃ≦１.５ｄの関係を満たすことを特徴とする燃料噴射弁。 A nozzle hole plate having a plurality of nozzle holes, a valve seat having a valve seat part that forms a cavity together with the nozzle hole plate and has an end face whose diameter increases toward the downstream side, and a seat surface of the valve seat part A valve body having a tip valve portion that opens and closes the nozzle hole, and opens the valve body when the valve body moves downstream, and the valve opening operation is performed when the tip valve portion contacts the nozzle hole plate. A fuel injection device of an outer valve-opening type to be completed,
On the downstream side of the valve seat portion, an extended taper surface that continuously extends on the seat surface and has a different inclination angle is formed, and the tip valve portion is separated from and in contact with the seat surface. And a bottom part that contacts the nozzle hole plate at the end of valve opening, and the inlet part of the nozzle hole is radially outward of the valve seat axis of the valve seat from the outermost peripheral edge part of the tip valve part. And the center of the inlet part of the nozzle hole is arranged inside an imaginary circle formed in the nozzle hole plate by intersecting the line extending downstream of the seat surface and the nozzle hole plate. And the center of the outlet part of the nozzle hole is arranged radially outside the valve seat axis with respect to the center of the inlet part of the nozzle hole, and the seat of the valve seat axis and the valve seat part The narrow angle formed by the surface is α (≦ 90 °), and the narrow angle formed by the valve seat axis and the extended tapered surface When the angle is β (≦ 90 °), and the nozzle hole angle formed by the thickness direction of the nozzle plate and the axis of the nozzle hole is γ, | α−β | ≦ 20 ° and | α−γ | When satisfying the relationship of ≦ 30 ° and the height of the axial center of the valve seat axis of the cavity from the center of the inlet of the nozzle hole is hc and the diameter of the nozzle hole is d, πd 2 / A fuel injection valve characterized by satisfying a relationship of 4 ≦ hc ≦ 1.5d.
The nozzle hole has a sag at the nozzle hole inlet of the nozzle hole, and the sag is characterized in that the sag inside is larger than the outside in the radial direction of the valve seat axis. The fuel injection valve according to any one of claims 1 to 6.
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| JP2007071105A (en) * | 2005-09-07 | 2007-03-22 | Mitsubishi Electric Corp | Fuel injector |
| US20070204835A1 (en) * | 2004-12-15 | 2007-09-06 | Daguang Xi | Fuel Injection Nozzle |
| JP2008050968A (en) * | 2006-08-23 | 2008-03-06 | Hitachi Ltd | Fluid injection nozzle |
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| US20070204835A1 (en) * | 2004-12-15 | 2007-09-06 | Daguang Xi | Fuel Injection Nozzle |
| JP2007071105A (en) * | 2005-09-07 | 2007-03-22 | Mitsubishi Electric Corp | Fuel injector |
| JP2008050968A (en) * | 2006-08-23 | 2008-03-06 | Hitachi Ltd | Fluid injection nozzle |
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| JP2017020470A (en) * | 2015-07-15 | 2017-01-26 | 日立オートモティブシステムズ株式会社 | Flow control valve |
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