JP4127237B2 - Fuel injection nozzle - Google Patents

Fuel injection nozzle Download PDF

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JP4127237B2
JP4127237B2 JP2004132742A JP2004132742A JP4127237B2 JP 4127237 B2 JP4127237 B2 JP 4127237B2 JP 2004132742 A JP2004132742 A JP 2004132742A JP 2004132742 A JP2004132742 A JP 2004132742A JP 4127237 B2 JP4127237 B2 JP 4127237B2
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nozzle
nozzle hole
hole
fuel
fuel injection
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JP2005315136A (en
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栄次 伊藤
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Denso Corp
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Denso Corp
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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
    • 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
    • F02M61/1806—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for characterised by the arrangement of discharge orifices, e.g. orientation or size
    • F02M61/1846—Dimensional characteristics of discharge orifices
    • 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
    • F02M61/1806—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for characterised by the arrangement of discharge orifices, e.g. orientation or size
    • F02M61/1833—Discharge orifices having changing cross sections, e.g. being divergent

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)

Description

本発明は、例えばディーゼルエンジン等の内燃機関の気筒の燃焼室内に燃料噴射を実施する内燃機関用燃料噴射ノズルに関するもので、特に燃料噴射ポンプにより加圧されて高圧化された燃料を、直接噴射式ディーゼルエンジン等の内燃機関の気筒の燃焼室内に噴射する内燃機関用燃料噴射ノズルを備えた内燃機関用燃料噴射装置に係わる。   The present invention relates to a fuel injection nozzle for an internal combustion engine that injects fuel into a combustion chamber of a cylinder of an internal combustion engine such as a diesel engine, and in particular, directly injects fuel pressurized by a fuel injection pump to increase its pressure. The present invention relates to a fuel injection device for an internal combustion engine provided with a fuel injection nozzle for an internal combustion engine that injects into a combustion chamber of a cylinder of the internal combustion engine such as a diesel engine.

［従来の技術］
近年、ディーゼルエンジンの排気ガス規制強化に対応し、エンジンより排出される排気ガスをクリーンにする、特に黒煙を代表とするディーゼルパティキュレートを低減化するためには、燃料噴射ノズルの噴孔部から噴射される燃料を極限まで微粒化することが重要である。この燃料の微粒化を促進するためには、燃料の高噴射圧化と噴孔部の小噴孔径化とが有効であるが、ディーゼルエンジン用燃料噴射システムにおける高圧力化は限界に近づいており、小噴孔径化が進んでいる。ここで、小噴孔径化を図った燃料噴射ノズルが提案されている（例えば、特許文献１参照）。 [Conventional technology]
In recent years, in order to respond to the tightening of exhaust gas regulations of diesel engines and to clean exhaust gases exhausted from engines, especially to reduce diesel particulates typified by black smoke, the nozzle hole part of the fuel injection nozzle It is important to atomize the fuel injected from In order to promote the atomization of fuel, it is effective to increase the injection pressure of fuel and to reduce the diameter of the injection hole, but the increase in pressure in the fuel injection system for diesel engines is approaching the limit. The diameter of small nozzle holes is increasing. Here, a fuel injection nozzle having a small nozzle hole diameter has been proposed (see, for example, Patent Document 1).

これは、図７に示したように、小噴孔径化した場合に必要な燃料噴射量を確保するために、ノズルボデー１０１の先端部に設けられる噴孔部１０２の噴孔断面積を噴孔入口部１０３から噴孔出口部１０４に向かって順次減少させて、噴孔部１０２内における圧力損失を極力低減することで、燃料噴射ポンプが発生した燃料圧力を有効に使い、燃料噴射ノズルの噴孔部１０２の噴孔出口部１０４から噴射される燃料噴霧の微粒化を促進するものである。なお、１０５は、ノズルボデー１０１の先端部に設けられる半球面形状の円頂部である。この円頂部１０５の内部には、ノズルニードルがノズルボデー１０１の弁座部より離座した際に、ノズルボデー１０１の内壁面とノズルニードルの円錐面との間に、弁座部から噴孔部１０２に至る燃料通路１０６の下流側に設けられるサックボリューム１０７が形成されている。   As shown in FIG. 7, in order to secure the fuel injection amount necessary when the diameter of the nozzle hole is reduced, the nozzle hole cross-sectional area of the nozzle hole part 102 provided at the tip part of the nozzle body 101 is used as the nozzle hole inlet. The fuel pressure generated by the fuel injection pump is effectively used by reducing the pressure loss in the nozzle hole portion 102 as much as possible from the nozzle portion 103 toward the nozzle hole outlet portion 104 in order. The atomization of the fuel spray injected from the nozzle hole outlet portion 104 of the portion 102 is promoted. Reference numeral 105 denotes a hemispherical circular top provided at the tip of the nozzle body 101. Inside the circular top portion 105, when the nozzle needle is separated from the valve seat portion of the nozzle body 101, the valve seat portion enters the nozzle hole portion 102 between the inner wall surface of the nozzle body 101 and the conical surface of the nozzle needle. A sack volume 107 provided on the downstream side of the reaching fuel passage 106 is formed.

［従来の技術の不具合］
ところが、上記の特許文献１に記載の燃料噴射ノズル（従来の技術）では、噴孔部１０２の噴孔断面積を噴孔入口部１０３から噴孔出口部１０４に向かって順次減少させて、噴孔出口部１０４の流速に対して噴孔断面積の大きい噴孔入口部１０３の流速を遅くすることで、燃料流を整流し、噴孔部１０２を通過する際の燃料の圧力損失を低減するものであるが、噴孔部１０２内の乱れは小さくなる。これにより、燃料噴射ノズルの噴孔部１０２からの燃料噴射直後の霧化の核となるキャビティの発生がなくなり、燃料噴射ノズルの噴孔部１０２から噴射される燃料噴霧の微粒化効果が減少してしまうという問題が生じている。 [Conventional technical problems]
However, in the fuel injection nozzle described in Patent Document 1 (conventional technology), the injection hole cross-sectional area of the injection hole portion 102 is sequentially decreased from the injection hole inlet portion 103 toward the injection hole outlet portion 104 to perform injection. The fuel flow is rectified by reducing the flow velocity of the nozzle hole inlet section 103 having a large nozzle hole cross-sectional area with respect to the flow velocity of the hole outlet section 104, thereby reducing the pressure loss of fuel when passing through the nozzle hole section 102. However, the disturbance in the nozzle hole portion 102 is reduced. As a result, the generation of a cavity that becomes the atomization core immediately after fuel injection from the nozzle hole portion 102 of the fuel injection nozzle is eliminated, and the atomization effect of the fuel spray injected from the nozzle hole portion 102 of the fuel injection nozzle is reduced. There is a problem that

また、噴孔部１０２の噴孔断面積を噴孔入口部１０３から噴孔出口部１０４に向かって順次減少させることで、燃料噴霧の中心に集まる方向に燃料流線が向いている。これにより、燃料噴射ノズルの噴孔部１０２から噴射される燃料噴霧は、図７に示したように、細く長い燃料噴霧となり、エンジンの各気筒の燃焼室内の空気利用率を上げることが困難になるという問題が生じている。   Further, by sequentially decreasing the nozzle hole cross-sectional area of the nozzle hole part 102 from the nozzle hole inlet part 103 toward the nozzle hole outlet part 104, the fuel stream line is directed in the direction of gathering at the center of the fuel spray. As a result, the fuel spray injected from the nozzle hole portion 102 of the fuel injection nozzle becomes a thin and long fuel spray as shown in FIG. 7, making it difficult to increase the air utilization rate in the combustion chamber of each cylinder of the engine. The problem of becoming.

一方、図８に示したように、燃料噴射ノズルのノズルボデー１０１の円頂部１０５に設けられる噴孔部１０２の噴孔断面積を噴孔入口部１０３から噴孔出口部１０４に向かって順次増加させて、噴孔部１０２をディフューザ形状とした場合には、噴孔入口部１０３直後の噴孔径の拡大により、乱れが生じるため、燃料噴射ノズルの噴孔部１０２から噴射される燃料噴霧を微粒化することができる。しかし、図８に示したように、燃料噴射ノズルの噴孔部１０２から噴射された燃料噴霧は、分散し必要な噴霧貫通力が得られないという問題が生じる。
実用新案登録第２５１９５６８号公報（第１−４頁、第１−６図） On the other hand, as shown in FIG. 8, the nozzle hole cross-sectional area of the nozzle hole portion 102 provided in the circular top portion 105 of the nozzle body 101 of the fuel injection nozzle is sequentially increased from the nozzle hole inlet portion 103 toward the nozzle hole outlet portion 104. In the case where the nozzle hole portion 102 has a diffuser shape, turbulence occurs due to the expansion of the nozzle hole diameter immediately after the nozzle hole inlet portion 103. Therefore, the fuel spray injected from the nozzle hole portion 102 of the fuel injection nozzle is atomized. can do. However, as shown in FIG. 8, the fuel spray injected from the nozzle hole portion 102 of the fuel injection nozzle is dispersed and a necessary spray penetration force cannot be obtained.
Utility Model Registration No. 2519568 (Page 1-4, Figure 1-6)

本発明は、ノズルボデーの先端部に設けられる噴孔部の噴孔入口部の噴孔最小径および噴孔出口部の噴孔最小径に対して噴孔拡大部の噴孔最大径を大きくすることで、高貫通力で、且つ燃料噴霧の微粒化の促進を図ることのできる燃料噴射ノズルを提供することにある。   The present invention increases the nozzle hole maximum diameter of the nozzle hole expanding portion with respect to the nozzle hole minimum diameter of the nozzle hole inlet portion and the nozzle hole minimum diameter of the nozzle hole outlet portion provided at the tip of the nozzle body. Then, it is providing the fuel-injection nozzle which can aim at acceleration | stimulation of atomization of fuel spray with high penetration force.

請求項１に記載の発明によれば、ノズルボデーの内壁で開口した噴孔入口部の噴孔最小径をφＤ１、ノズルボデーの外壁で開口した噴孔出口部の噴孔最小径をφＤ２、噴孔入口部と噴孔出口部との間に設けられる噴孔拡大部の噴孔最大径をφＤ３としたとき、φＤ１＜φＤ３で、且つφＤ２＜φＤ３の関係を満足するように、ノズルボデーの先端部に噴孔部を設けることにより、噴孔入口部の噴孔最小径および噴孔出口部の噴孔最小径に対して噴孔拡大部の噴孔最大径を大きくすることが可能となり、噴孔入口部および噴孔出口部よりも噴孔拡大部の噴孔断面積を拡げることが可能となる。   According to the first aspect of the present invention, the minimum nozzle hole diameter of the nozzle hole opening portion opened at the inner wall of the nozzle body is φD1, the minimum nozzle hole diameter of the nozzle hole outlet portion opened at the outer wall of the nozzle body is φD2, and the nozzle hole inlet When the maximum nozzle hole diameter of the nozzle hole expansion part provided between the nozzle part and the nozzle hole outlet part is φD3, the nozzle body is sprayed to the tip of the nozzle body so that φD1 <φD3 and φD2 <φD3 are satisfied. By providing the hole portion, it is possible to increase the maximum nozzle hole diameter of the nozzle hole expanding portion relative to the nozzle hole minimum diameter of the nozzle hole inlet portion and the nozzle hole minimum diameter of the nozzle hole outlet portion. In addition, it is possible to expand the nozzle hole cross-sectional area of the nozzle hole expanding part rather than the nozzle hole outlet part.

これによって、噴孔入口部から噴孔拡大部に至る噴孔部内の燃料の流れに乱れが発生するため、燃料噴射後の燃料噴霧の微粒化の核となるキャビティ（気泡）が生成される。その後、噴孔拡大部から噴孔出口部に至る噴孔部内の燃料の流れ内にキャビティを取り込んだ状態で、噴孔出口部の中心軸線に向かって収束しながら、内燃機関の気筒の燃焼室内に噴射される。したがって、燃料噴射の直後から燃料噴霧の微粒化を促進でき、且つ高貫通力の燃料噴霧を噴射することができる。すなわち、燃料噴霧を分散させることなく、内燃機関の気筒の燃焼室内の狙った方向に燃料噴霧を噴射させることができる。この結果、噴孔部の噴孔出口部から内燃機関の気筒の燃焼室内に噴射される燃料噴霧は、太くて長い燃料噴霧となり、内燃機関の気筒の燃焼室内全体に行き渡るので、内燃機関の気筒の燃焼室内の空気利用率を上げることができ、良好な燃焼を確保できる。これにより、内燃機関の気筒の燃焼室内の燃焼状態を改善できるので、内燃機関の排気ガス性能を向上でき、且つ内燃機関の出力を向上できる。   As a result, the flow of fuel in the nozzle hole part extending from the nozzle hole inlet part to the nozzle hole enlarged part is disturbed, so that a cavity (bubble) serving as a nucleus for atomization of fuel spray after fuel injection is generated. Thereafter, in a state where the cavity is taken into the flow of fuel in the nozzle hole portion extending from the nozzle hole expanding portion to the nozzle hole outlet portion, the cavity is converged toward the central axis of the nozzle hole outlet portion, and the combustion chamber of the cylinder of the internal combustion engine is Is injected into. Therefore, atomization of the fuel spray can be promoted immediately after the fuel injection, and the fuel spray having a high penetration force can be injected. That is, the fuel spray can be injected in the target direction in the combustion chamber of the cylinder of the internal combustion engine without dispersing the fuel spray. As a result, the fuel spray injected from the nozzle hole outlet of the nozzle hole into the combustion chamber of the cylinder of the internal combustion engine becomes a thick and long fuel spray and spreads throughout the combustion chamber of the cylinder of the internal combustion engine. The air utilization rate in the combustion chamber can be increased, and good combustion can be ensured. Thereby, since the combustion state in the combustion chamber of the cylinder of the internal combustion engine can be improved, the exhaust gas performance of the internal combustion engine can be improved and the output of the internal combustion engine can be improved.

さらに、請求項１に記載の発明によれば、噴孔入口部から噴孔拡大部に向かって噴孔断面積が次第に大きくなるように形成された噴孔拡大流路の噴孔軸線方向の長さをＬ１、噴孔拡大部から噴孔出口部に向かって噴孔断面積が次第に小さくなるように形成された噴孔縮小流路の噴孔軸線方向の長さをＬ２としたとき、Ｌ１＜Ｌ２の関係を満足するように、ノズルボデーの先端部に噴孔部を設けることにより、噴孔縮小流路に対して噴孔拡大流路を急拡大とすることが可能となる。これによって、噴孔拡大部に対して噴孔断面積（噴孔径）が小径の噴孔入口部以降の噴孔拡大流路では、噴孔径が急拡大するため、燃料の流れは乱れ、燃料噴射後の燃料噴霧の微粒化の核となるキャビティが良好に生成される。 Furthermore, according to the first aspect of the present invention, the length of the nozzle hole expanding channel formed in such a manner that the nozzle hole sectional area gradually increases from the nozzle hole inlet part toward the nozzle hole expanding part. When the length in the nozzle hole axial direction of the nozzle hole reducing channel formed so that the nozzle hole cross-sectional area gradually decreases from the nozzle hole expanding part toward the nozzle hole outlet part is L1, L1 < By providing the nozzle hole at the tip of the nozzle body so as to satisfy the relationship of L2, it is possible to make the nozzle hole expanding channel rapidly expand with respect to the nozzle hole reducing channel. As a result, in the nozzle hole enlargement channel after the nozzle hole inlet part where the nozzle hole cross-sectional area (nozzle hole diameter) is smaller than the nozzle hole expanding part, the nozzle hole diameter rapidly expands, so that the fuel flow is disturbed and the fuel injection The cavity which becomes the nucleus of atomization of the later fuel spray is generated well.

請求項２に記載の発明によれば、ノズルニードルがノズルボデーの弁座部より離座した際に、ノズルボデーの内壁とノズルニードルとの間に弁座部から噴孔部に至る燃料通路を形成している。そして、噴孔部の噴孔軸線方向を、燃料通路を流れる燃料の流れ方向に対して所定の傾斜角度だけ傾いて配置することにより、燃料通路から噴孔部の噴孔入口部に流入する燃料流は急激に曲げられる。
請求項３に記載の発明によれば、ノズルボデーの内壁から噴孔入口部の噴孔最小径に至る部分に、面取りが施された面取り部を設けることにより、燃料通路から噴孔部の噴孔入口部に燃料流が入る時の曲がり圧力損失を低減することができる。 According to the second aspect of the present invention, when the nozzle needle is separated from the valve seat portion of the nozzle body, a fuel passage extending from the valve seat portion to the nozzle hole portion is formed between the inner wall of the nozzle body and the nozzle needle. ing. Then, by arranging the nozzle hole axial direction of the nozzle hole portion at a predetermined inclination angle with respect to the flow direction of the fuel flowing through the fuel passage, the fuel flowing into the nozzle hole inlet portion of the nozzle hole portion from the fuel passage The flow is bent sharply.
According to the third aspect of the present invention, the chamfered chamfered portion is provided in the portion from the inner wall of the nozzle body to the nozzle hole minimum diameter of the nozzle hole inlet, so that the nozzle hole of the nozzle hole from the fuel passage is provided. The bending pressure loss when the fuel flow enters the inlet can be reduced.

請求項４に記載の発明によれば、ノズルボデーの先端部に、内部にサックボリュームを形成する略半球状の円頂部を設けている。その円頂部の略同一円周上に複数の噴孔部を配置することにより、内燃機関の気筒の燃焼室内の隅々まで燃料噴霧を噴射することができ、内燃機関の気筒の燃焼室内の空気利用率を上げることができ、良好な燃焼を確保できる。これにより、内燃機関の気筒の燃焼室内の燃焼状態を改善できるので、内燃機関の排気ガス性能を向上でき、且つ内燃機関の出力を向上できる。 According to invention of Claim 4 , the substantially hemispherical top part which forms a sac volume inside is provided in the front-end | tip part of a nozzle body. By arranging a plurality of nozzle holes on substantially the same circumference of the top of the circle, fuel spray can be injected to every corner of the combustion chamber of the cylinder of the internal combustion engine, and the air in the combustion chamber of the cylinder of the internal combustion engine The utilization rate can be increased and good combustion can be secured. Thereby, since the combustion state in the combustion chamber of the cylinder of the internal combustion engine can be improved, the exhaust gas performance of the internal combustion engine can be improved and the output of the internal combustion engine can be improved.

本発明を実施するための最良の形態は、例えばディーゼルエンジン等の内燃機関用の燃料噴射ノズルの噴孔部から噴射される燃料噴霧の微粒化と高噴霧貫通力とを両立させるという目的を、ノズルボデーの先端部に設けられる噴孔部の噴孔入口部の噴孔最小径および噴孔出口部の噴孔最小径に対して、噴孔入口部と噴孔出口部との間に設けられる噴孔拡大部の噴孔最大径を大きくすることで実現した。   The best mode for carrying out the present invention aims to achieve both the atomization of fuel spray injected from the injection hole portion of a fuel injection nozzle for an internal combustion engine such as a diesel engine and the high spray penetration force. The nozzle provided between the nozzle hole inlet part and the nozzle hole outlet part with respect to the nozzle hole minimum diameter of the nozzle hole inlet part and the nozzle hole minimum diameter of the nozzle hole outlet part of the nozzle hole part provided at the tip of the nozzle body. This was realized by increasing the maximum diameter of the nozzle hole in the hole expansion part.

［実施例１の構成］
図１ないし図４は本発明の実施例１を示したもので、図１は燃料噴射ノズルの全体構成を示した図で、図２は燃料噴射ノズルの主要構成を示した図である。 [Configuration of Example 1]
1 to 4 show a first embodiment of the present invention. FIG. 1 is a diagram showing the overall configuration of the fuel injection nozzle, and FIG. 2 is a diagram showing the main configuration of the fuel injection nozzle.

本実施例の燃料噴射ノズル（以下燃料噴射ノズルと略す）は、図示しない多気筒ディーゼルエンジン等の内燃機関（以下エンジンと言う）の各気筒毎に対応して搭載されて、図示しない列型燃料噴射ポンプや分配型燃料噴射ポンプ等の燃料噴射ポンプの加圧室内で加圧されて高圧化された高圧燃料を、直接エンジンの各気筒の燃焼室内に霧状に噴射供給する直接噴射タイプのホール型燃料噴射ノズルである。この燃料噴射ノズルは、ノズルニードル１を摺動自在に収容するノズルボデー２と、図示しないニードル付勢手段としてのスプリングを収容するノズルホルダー（図示せず）と、ノズルボデー２の密着面とノズルホルダーの密着面との間に配置されたチップパッキン（図示せず）と、このチップパッキンを介してノズルボデー２の密着面とノズルホルダーの密着面とを所定の締結軸力によって締め付け固定するためのリテーニングナット（図示せず）とから構成されている。   A fuel injection nozzle (hereinafter abbreviated as a fuel injection nozzle) of this embodiment is mounted corresponding to each cylinder of an internal combustion engine (hereinafter referred to as an engine) such as a multi-cylinder diesel engine (not shown), and is not shown in a row type fuel. A direct injection type hole that directly injects high-pressure fuel that has been pressurized and pressurized in the pressure chamber of a fuel injection pump such as an injection pump or a distributed fuel injection pump directly into the combustion chamber of each cylinder of the engine. Type fuel injection nozzle. This fuel injection nozzle includes a nozzle body 2 that slidably accommodates a nozzle needle 1, a nozzle holder (not shown) that accommodates a spring as a needle biasing means (not shown), a close contact surface of the nozzle body 2, and a nozzle holder A tip packing (not shown) disposed between the contact surface and a retaining for fastening and fixing the contact surface of the nozzle body 2 and the contact surface of the nozzle holder with a predetermined fastening axial force via the chip packing. It consists of a nut (not shown).

なお、ノズルボデー２には、密着面から油溜り室４へ延びる燃料送出路（以下燃料孔と言う）３が設けられている。また、ノズルホルダーには、継手部から密着面へ延びる燃料供給路（図示せず）が設けられている。また、チップパッキンには、ノズルボデー２の燃料孔３とノズルホルダーの燃料供給路とを連通する燃料中継路（図示せず）が設けられている。また、チップパッキンの端面には、ノズルニードル１の最大リフト量を規制する規制面が設けられている。   The nozzle body 2 is provided with a fuel delivery path (hereinafter referred to as a fuel hole) 3 extending from the contact surface to the oil sump chamber 4. Further, the nozzle holder is provided with a fuel supply path (not shown) extending from the joint portion to the contact surface. Further, the chip packing is provided with a fuel relay path (not shown) that connects the fuel hole 3 of the nozzle body 2 and the fuel supply path of the nozzle holder. Further, a restriction surface for restricting the maximum lift amount of the nozzle needle 1 is provided on the end face of the tip packing.

ノズルニードル１は、例えば炭素鋼等の金属材料によって略丸棒形状に形成されて、ノズルホルダー内に収容されたスプリング等のニードル付勢手段の付勢力によって噴孔部９を閉じる方向に常に付勢されており、先端部がノズルボデー２のシート面１０の弁座に着座、離脱して、噴孔部９を閉塞、開放するものである。このノズルニードル１は、単純な円柱面形状の軸方向部１１とこの軸方向部１１よりも外径が小さい単純な円柱面形状の軸方向部１２との間に径小部１３を有している。なお、ノズルニードル１の軸方向部１１は、ノズルボデー２の軸方向孔６の図示上部側に設けられる摺動孔７内において摺動自在に保持されている。また、軸方向部１１の図示上端面より軸方向に突出した凸状部１７の周りには、ノズルニードル１が最もリフトした際にチップパッキンの規制面に当接する円環状の肩部１８が形成されている。そして、ノズルニードル１は、軸方向部１２とノズルボデー２の軸方向孔６との間に所定のクリアランスを保って往復移動自在に収容されている。そのクリアランスは、油溜り室４からシート面１０へ延びる燃料通路５を形成している。   The nozzle needle 1 is formed in a substantially round bar shape with a metal material such as carbon steel, for example, and is always applied in a direction to close the nozzle hole 9 by the urging force of a needle urging means such as a spring housed in the nozzle holder. The tip is seated on and disengaged from the valve seat on the seat surface 10 of the nozzle body 2 to close and open the nozzle hole 9. The nozzle needle 1 has a small diameter portion 13 between a simple cylindrical surface-shaped axial portion 11 and a simple cylindrical surface-shaped axial portion 12 having an outer diameter smaller than that of the axial direction portion 11. Yes. The axial portion 11 of the nozzle needle 1 is slidably held in a sliding hole 7 provided on the upper side in the figure of the axial hole 6 of the nozzle body 2. In addition, an annular shoulder portion 18 is formed around the convex portion 17 protruding in the axial direction from the upper end surface of the axial direction portion 11 when the nozzle needle 1 is most lifted. Has been. The nozzle needle 1 is accommodated in a reciprocating manner with a predetermined clearance between the axial portion 12 and the axial hole 6 of the nozzle body 2. The clearance forms a fuel passage 5 extending from the oil reservoir 4 to the seat surface 10.

ノズルニードル１の燃料流方向の下流側（図１および図２において図示下端側）の先端部には、概略２段の円錐形状面が設けられており、それらの円錐形状面間に設けられる円環状の稜線（エッジ）には、ノズルボデー２の先端部に形成されたシート面１０の弁座に液密的に接触（着座）して燃料通路５と燃料通路１４との連通状態を遮断するためのシート部１５が形成されている。なお、ノズルニードル１のシート部１５よりも先端側には、先端円錐面１６が形成されている。また、ノズルニードル１の開弁方向の移動（リフト）によって、シート部１５をノズルボデー２のシート面１０の弁座から離脱（リフト）させた場合には、燃料通路５と燃料通路１４とは連通状態（開放状態）となり、燃料通路５側から供給される燃料を噴孔部９側の燃料通路１４へと通過させる。   The tip of the nozzle needle 1 on the downstream side in the fuel flow direction (the lower end in the drawing in FIGS. 1 and 2) is provided with a substantially two-stage conical surface, and a circle provided between the conical surfaces. In order to block the communication state between the fuel passage 5 and the fuel passage 14 by liquid-tight contact (sitting) with the valve seat of the seat surface 10 formed at the tip of the nozzle body 2 at the annular ridgeline (edge). Sheet portion 15 is formed. A tip conical surface 16 is formed on the tip side of the nozzle needle 1 with respect to the sheet portion 15. Further, when the seat portion 15 is separated (lifted) from the valve seat of the seat surface 10 of the nozzle body 2 by the movement (lift) of the nozzle needle 1 in the valve opening direction, the fuel passage 5 and the fuel passage 14 communicate with each other. In this state (open state), the fuel supplied from the fuel passage 5 side is allowed to pass to the fuel passage 14 on the nozzle hole 9 side.

ノズルボデー２は、例えば炭素鋼等の金属材料によって略円筒形状に形成されている。そのノズルボデー２の先端側の円頂部２４には、エンジンの各気筒の燃焼室内に燃料を噴射するための噴孔部９が設けられている。そして、ノズルボデー２の拡大部には、密着面より噴孔部９側へと延びる軸方向孔６が設けられ、その軸方向孔６の図示上端側には、軸方向孔６よりも孔径が窄められて、ノズルニードル１を摺動自在に保持するための摺動孔７が設けられ、軸方向孔６と摺動孔７との間には、軸方向孔６および摺動孔７よりも孔径が拡げられた油溜り室４が設けられている。   The nozzle body 2 is formed in a substantially cylindrical shape by a metal material such as carbon steel. A nozzle hole portion 9 for injecting fuel into the combustion chamber of each cylinder of the engine is provided at the top 24 of the tip of the nozzle body 2. The enlarged portion of the nozzle body 2 is provided with an axial hole 6 extending from the contact surface toward the nozzle hole 9, and the diameter of the axial hole 6 is narrower than the axial hole 6 at the upper end in the figure. Therefore, a sliding hole 7 is provided for slidably holding the nozzle needle 1, and between the axial hole 6 and the sliding hole 7 than the axial hole 6 and the sliding hole 7. An oil sump chamber 4 having an enlarged hole diameter is provided.

そのノズルボデー２は、図示上端側から図示下端側に向かって、円筒壁部２１、この円筒壁部２１よりも外径の小さい円筒壁部２２、この円筒壁部２２よりも外径の小さい円筒壁部２３、およびこの円筒壁部２３よりも外径が小さく、略逆円錐形状の円頂部（テーパ壁部）２４が順に設けられている。なお、円筒壁部２１内には、チップパッキンを介してノズルホルダーの密着面に液密的に当接する密着面（ノズルボデー２の密着面）から油溜り室４へ斜めに延びる燃料孔３が設けられている。また、円筒壁部２２、２３内には、摺動孔７よりも孔径が拡げられた軸方向孔６が形成され、その軸方向孔６とノズルニードル１の軸方向部１２との間には、油溜り室４から噴孔部９側へ軸方向に真っ直ぐ延びる燃料通路５が形成されている。そして、ノズルボデー２の円頂部２４の内周面には、燃料噴射終了時にノズルニードル１のシート部１５が着座する弁座を有する逆円錐面形状のシート面１０が形成されている。   The nozzle body 2 includes a cylindrical wall portion 21, a cylindrical wall portion 22 having a smaller outer diameter than the cylindrical wall portion 21, and a cylindrical wall having a smaller outer diameter than the cylindrical wall portion 22 from the upper end side in the drawing toward the lower end side in the drawing. The outer diameter is smaller than this part 23 and this cylindrical wall part 23, and the substantially inverted conical circular top part (taper wall part) 24 is provided in order. A fuel hole 3 extending obliquely from the contact surface (contact surface of the nozzle body 2) in liquid-tight contact with the contact surface of the nozzle holder via the tip packing to the oil sump chamber 4 is provided in the cylindrical wall portion 21. It has been. An axial hole 6 having a larger diameter than the sliding hole 7 is formed in the cylindrical wall portions 22 and 23, and between the axial hole 6 and the axial portion 12 of the nozzle needle 1. A fuel passage 5 that extends straight from the oil reservoir chamber 4 to the nozzle hole 9 side in the axial direction is formed. An inverted conical seat surface 10 having a valve seat on which the seat portion 15 of the nozzle needle 1 is seated at the end of fuel injection is formed on the inner peripheral surface of the circular top portion 24 of the nozzle body 2.

また、ノズルボデー２の円頂部２４には、サックボリューム（サック室）２５が形成されている。そして、ノズルボデー２の噴孔部９には、ノズルボデー２のシート面１０の弁座よりも燃料流方向の下流側の円頂部２４の内壁面から外壁面（エンジンの各気筒の燃焼室内に露出する面）までを斜めに貫通する複数の噴孔流路が形成されている。そして、これらの噴孔流路は、図２ないし図４に示したように、ノズルボデー２の円頂部２４の内壁面で開口した噴孔入口部３１、ノズルボデー２の円頂部２４の外壁面で開口した噴孔出口部３２、および噴孔入口部３１と噴孔出口部３２との間に設置された噴孔拡大部３３等から構成されている。なお、複数の噴孔流路は、ノズルボデー２の円頂部２４の周方向に所定の間隔（例えば９０°の等間隔）で４個形成されている。   Further, a sac volume (sack chamber) 25 is formed at the circular top 24 of the nozzle body 2. The nozzle body 2 has an injection hole 9 exposed from the inner wall surface of the circular top portion 24 downstream of the valve seat of the seat surface 10 of the nozzle body 2 to the outer wall surface (inside the combustion chamber of each cylinder of the engine). A plurality of nozzle hole passages obliquely penetrating up to the surface) are formed. As shown in FIGS. 2 to 4, these nozzle hole channels are opened at the nozzle hole inlet 31 that opens at the inner wall surface of the circular top 24 of the nozzle body 2 and at the outer wall surface of the circular top 24 of the nozzle body 2. And the nozzle hole expanding part 33 installed between the nozzle hole inlet part 31 and the nozzle hole outlet part 32. Note that four nozzle hole channels are formed at predetermined intervals (for example, at equal intervals of 90 °) in the circumferential direction of the circular top portion 24 of the nozzle body 2.

ノズルボデー２の噴孔部９のうちの噴孔入口部３１は、略円形状の断面を有し、噴孔拡大部３３よりも燃料の流れ方向の上流側に設けられている。この噴孔入口部３１は、ノズルボデー２の円頂部２４の半径方向にドリル等の工具によってノズルボデー２の円頂部２４の内壁面から噴孔拡大部３３までを連通するように穿設されている。また、噴孔入口部３１は、噴孔拡大部３３よりも噴孔断面積（噴孔径）が小さく、噴孔出口部３２および噴孔拡大部３３に対して略同一の噴孔軸線上に設けられている。   The nozzle hole inlet portion 31 in the nozzle hole portion 9 of the nozzle body 2 has a substantially circular cross section, and is provided upstream of the nozzle hole expanding portion 33 in the fuel flow direction. The injection hole inlet 31 is formed so as to communicate from the inner wall surface of the circular top 24 of the nozzle body 2 to the injection hole enlarged portion 33 by a tool such as a drill in the radial direction of the circular top 24 of the nozzle body 2. The nozzle hole inlet 31 has a nozzle hole cross-sectional area (a nozzle hole diameter) smaller than that of the nozzle hole expanding part 33, and is provided on the nozzle hole axis substantially the same as the nozzle hole outlet part 32 and the nozzle hole expanding part 33. It has been.

ノズルボデー２の噴孔部９のうちの噴孔出口部３２は、略円形状の断面を有し、噴孔拡大部３３よりも燃料の流れ方向の下流側に設けられている。この噴孔出口部３２は、ノズルボデー２の円頂部２４の半径方向にドリル等の工具によってノズルボデー２の円頂部２４の外壁面から噴孔拡大部３３までを連通するように穿設されている。また、噴孔出口部３２は、噴孔拡大部３３よりも噴孔断面積（噴孔径）が小さく、噴孔入口部３１および噴孔拡大部３３に対して略同一の噴孔軸線上に設けられている。   The nozzle hole outlet portion 32 of the nozzle hole portion 9 of the nozzle body 2 has a substantially circular cross section, and is provided downstream of the nozzle hole expanding portion 33 in the fuel flow direction. The injection hole outlet 32 is formed in the radial direction of the circular top part 24 of the nozzle body 2 so as to communicate from the outer wall surface of the circular top part 24 of the nozzle body 2 to the injection hole expanding part 33 by a tool such as a drill. Further, the nozzle hole outlet portion 32 has a nozzle hole cross-sectional area (a nozzle hole diameter) smaller than that of the nozzle hole expanding portion 33, and is provided on the nozzle hole axis substantially the same as the nozzle hole inlet portion 31 and the nozzle hole expanding portion 33. It has been.

ノズルボデー２の噴孔部９のうちの噴孔拡大部３３は、略円形状の断面を有し、噴孔入口部３１よりも燃料の流れ方向の下流側で、且つ噴孔出口部３２よりも燃料の流れ方向の上流側に設けられている。また、噴孔拡大部３３は、噴孔入口部３１の噴孔最小径および噴孔出口部３２の噴孔最小径よりも噴孔断面積（噴孔径）が大きい噴孔最大径を有している。   The nozzle hole enlargement part 33 of the nozzle hole part 9 of the nozzle body 2 has a substantially circular cross section, is located downstream of the nozzle hole inlet part 31 in the fuel flow direction and from the nozzle hole outlet part 32. It is provided on the upstream side in the fuel flow direction. Further, the nozzle hole expanding portion 33 has a nozzle hole maximum diameter having a nozzle hole cross-sectional area (a nozzle hole diameter) larger than the nozzle hole minimum diameter of the nozzle hole inlet portion 31 and the nozzle hole minimum diameter of the nozzle hole outlet portion 32. Yes.

ここで、本実施例の噴孔部９の各噴孔流路は、噴孔入口部３１の噴孔最小径をφＤ１とし、また、噴孔出口部３２の噴孔最小径をφＤ２とし、また、噴孔拡大部３３の噴孔最大径をφＤ３としたときに、φＤ１＜φＤ３で、且つφＤ２＜φＤ３の関係を満足するように、噴孔入口部３１の噴孔最小径（φＤ１）、噴孔出口部３２の噴孔最小径（φＤ２）および噴孔拡大部３３の噴孔最大径（φＤ３）を設定している。また、本実施例では、燃料噴霧の高貫通力を得るために、φＤ１＞φＤ２の関係を満足するように、噴孔入口部３１の噴孔最小径（φＤ１）および噴孔出口部３２の噴孔最小径（φＤ２）を設定している。また、φＤ３−φＤ１＝１０〜２０μｍ、およびφＤ３−φＤ２＝１５〜２５μｍの関係を満足するように、噴孔入口部３１の噴孔最小径（φＤ１）、噴孔出口部３２の噴孔最小径（φＤ２）および噴孔拡大部３３の噴孔最大径（φＤ３）を設定している。また、ノズルボデー２の円頂部２４の内壁面から噴孔入口部３１の噴孔最小径に至る部分には、燃料通路１４から噴孔入口部３１に燃料流が入る時の曲がり圧力損失を低減するためにＲ形状の面取りが施された面取り部３４が設けられている。ここで、面取り部３４の半径をＲとしたときに、２Ｒ＝φＤ１または２Ｒ＝φＤ２の関係を満足するように設定している。   Here, each nozzle hole flow path of the nozzle hole portion 9 of the present embodiment has a minimum nozzle hole diameter of the nozzle hole inlet portion 31 as φD1, and a nozzle hole minimum diameter of the nozzle hole outlet portion 32 as φD2. When the maximum diameter of the nozzle hole of the nozzle hole expanding portion 33 is φD3, the minimum nozzle hole diameter (φD1) of the nozzle hole inlet 31 is set so that the relationship of φD1 <φD3 and φD2 <φD3 is satisfied. The minimum nozzle hole diameter (φD2) of the hole outlet portion 32 and the maximum nozzle hole diameter (φD3) of the nozzle hole expanding portion 33 are set. Further, in this embodiment, in order to obtain the high penetration force of the fuel spray, the injection hole minimum diameter (φD1) of the injection hole inlet 31 and the injection of the injection hole outlet 32 are satisfied so as to satisfy the relationship of φD1> φD2. The minimum hole diameter (φD2) is set. Further, the minimum injection hole diameter (φD1) of the injection hole inlet portion 31 and the minimum injection hole diameter of the injection hole outlet portion 32 so as to satisfy the relationship of φD3-φD1 = 10-20 μm and φD3-φD2 = 15-25 μm. (ΦD2) and the nozzle hole maximum diameter (φD3) of the nozzle hole expanding portion 33 are set. Further, in the portion from the inner wall surface of the circular top portion 24 of the nozzle body 2 to the nozzle hole minimum diameter of the nozzle hole inlet portion 31, bending pressure loss when the fuel flow enters the nozzle hole inlet portion 31 from the fuel passage 14 is reduced. For this purpose, a chamfered portion 34 having an R-shaped chamfer is provided. Here, when the radius of the chamfer 34 is R, it is set so as to satisfy the relationship of 2R = φD1 or 2R = φD2.

また、本実施例の噴孔部９の各噴孔流路には、噴孔入口部３１の噴孔最小径から噴孔拡大部３３の噴孔最大径に向かって噴孔断面積（噴孔径）が次第に大きくなるように形成された噴孔拡大流路３５、および噴孔拡大部３３の噴孔最大径から噴孔出口部３２の噴孔最小径に向かって噴孔断面積（噴孔径）が次第に小さくなるように形成された噴孔縮小流路３６を有している。ここで、噴孔拡大流路３５の噴孔軸線方向の長さをＬ１とし、また、噴孔縮小流路３６の噴孔軸線方向の長さをＬ２としたときに、Ｌ１＜Ｌ２の関係を満足するように設定している。なお、Ｌ１は燃料噴霧の微粒化を促進させるために、０．１５〜０．４５ｍｍの範囲が望ましく、０．３０ｍｍ程度が最も望ましい。また、Ｌ２は燃料噴霧の高貫通力を得るために、０．７５〜１．２５ｍｍの範囲が望ましく、１．００ｍｍ程度が最も望ましい。また、噴孔拡大流路３５の噴孔軸線方向に対する傾斜角度をθ１とし、また、噴孔縮小流路３６の噴孔軸線方向に対する傾斜角度をθ２としたときに、θ１＞θ２の関係を満足するように設定している。すなわち、噴孔拡大流路３５の傾斜角度は、噴孔縮小流路３６の緩やかな収束角度に対して急拡大な角度となる。   Moreover, in each nozzle hole flow path of the nozzle hole part 9 of the present embodiment, the nozzle hole cross-sectional area (the nozzle hole diameter) from the nozzle hole minimum diameter of the nozzle hole inlet part 31 toward the nozzle hole maximum diameter of the nozzle hole expanding part 33. ) And the nozzle hole cross-sectional area (nozzle hole diameter) from the nozzle hole maximum diameter of the nozzle hole expanding part 33 toward the nozzle hole minimum diameter of the nozzle hole outlet part 32. The nozzle hole reducing flow path 36 is formed so as to gradually become smaller. Here, when the length in the nozzle hole axial direction of the nozzle hole expanding channel 35 is L1, and the length in the nozzle hole axial direction of the nozzle hole reducing channel 36 is L2, the relationship of L1 <L2 is established. Set to be satisfied. In order to promote atomization of fuel spray, L1 is preferably in the range of 0.15 to 0.45 mm, and most preferably about 0.30 mm. Further, L2 is preferably in the range of 0.75 to 1.25 mm and most preferably about 1.00 mm in order to obtain a high penetration force of fuel spray. Further, when the inclination angle of the nozzle hole expansion channel 35 with respect to the nozzle hole axis direction is θ1, and the inclination angle of the nozzle hole reduction channel 36 with respect to the nozzle hole axis direction is θ2, the relationship θ1> θ2 is satisfied. It is set to do. That is, the inclination angle of the nozzle hole expanding channel 35 is a sharply expanding angle with respect to the gentle convergence angle of the nozzle hole reducing channel 36.

［実施例１の作用］
次に、本実施例のディーゼルエンジン用の燃料噴射ノズルの作用を図１ないし図４に基づいて簡単に説明する。 [Operation of Example 1]
Next, the operation of the fuel injection nozzle for the diesel engine of this embodiment will be briefly described with reference to FIGS.

燃料噴射ポンプから所定量の燃料が所定の圧送時期に圧送され、この高圧燃料がいずれも図示しない噴射管、燃料噴射装置を経由して燃料孔３に供給される。この高圧燃料は、燃料孔３、油溜り室４を経由して、ノズルニードル１の軸方向部１２とノズルボデー２の軸方向孔６との間に形成される燃料通路５内に蓄えられる。その燃料通路５内の燃料圧力が増大して、ノズルホルダー内に収容されたスプリングの付勢力に打ち勝つ圧力に達すると、ノズルニードル１はノズルボデー２のシート面１０の弁座から離脱（リフト）する。例えばノズルニードル１の肩部１８がチップパッキン等の規制部材に到達するまでリフトする。   A predetermined amount of fuel is pumped from the fuel injection pump at a predetermined pumping timing, and this high-pressure fuel is supplied to the fuel hole 3 via an injection pipe and a fuel injection device (not shown). This high-pressure fuel is stored in a fuel passage 5 formed between the axial portion 12 of the nozzle needle 1 and the axial hole 6 of the nozzle body 2 via the fuel hole 3 and the oil reservoir 4. When the fuel pressure in the fuel passage 5 increases and reaches a pressure that overcomes the urging force of the spring accommodated in the nozzle holder, the nozzle needle 1 separates (lifts) from the valve seat on the seat surface 10 of the nozzle body 2. . For example, the nozzle needle 1 is lifted until the shoulder portion 18 reaches a regulating member such as a tip packing.

このノズルニードル１の開弁方向の移動（リフト）によって、ノズルニードル１のシート部１５がノズルボデー２のシート面１０の弁座から離脱（リフト）するため、燃料通路５と燃料通路１４とは連通状態（開放状態）となり、燃料孔３、油溜り室４および燃料通路５から供給される燃料がノズルボデー２の噴孔部９側の燃料通路１４へと流れ込む。そして、ノズルボデー２の噴孔部９側の燃料通路１４から噴孔部９へと流れ込んだ燃料流は、噴孔軸線方向に急激に曲げられるが、ノズルボデー２の円頂部２４の内壁面から噴孔部９の噴孔入口部３１の噴孔最小径に至る部分にＲ形状の面取り部３４が設けてあるため、曲がり圧力損失は最小となる。   Due to the movement (lift) of the nozzle needle 1 in the valve opening direction, the seat portion 15 of the nozzle needle 1 separates (lifts) from the valve seat of the seat surface 10 of the nozzle body 2, so that the fuel passage 5 and the fuel passage 14 communicate with each other. The fuel is supplied from the fuel hole 3, the oil sump chamber 4 and the fuel passage 5 into the fuel passage 14 on the nozzle hole 9 side of the nozzle body 2. The fuel flow that flows into the nozzle hole 9 from the fuel passage 14 on the nozzle hole 9 side of the nozzle body 2 is suddenly bent in the axial direction of the nozzle hole 2. Since the R-shaped chamfered portion 34 is provided at the portion of the portion 9 that reaches the minimum diameter of the nozzle hole of the nozzle hole inlet portion 31, bending pressure loss is minimized.

また、小径の噴孔入口部３１の噴孔最小径（φＤ１）から噴孔拡大部３３の噴孔最大径（φＤ３）に至る噴孔拡大流路３５の噴孔断面積（噴孔径）は、急拡大とされているため、噴孔拡大流路３５内を通過する際に燃料流が乱れ、燃料噴射後の燃料噴霧の微粒化の核となるキャビティ（気泡）が生成される。さらに、噴孔拡大流路３５の噴孔最大径（φＤ３）を越えて、噴孔拡大部３３の噴孔最大径（φＤ３）から小径の噴孔出口部３２の噴孔最小径（φＤ２）に至る噴孔縮小流路３６内に流入した燃料流は、噴孔縮小流路３６の噴孔断面積（噴孔径）が緩やかに狭くなるため、噴孔出口部３２に向かってもう一度噴孔軸線方向に収束される。そして、燃料は、噴孔部９の噴孔出口部３２から流出してエンジンの各気筒の燃焼室内に噴射される。そして、燃料噴射ポンプからの燃料圧送が終わりに近づくと、燃料通路５内の燃料圧力が低下するため、スプリングの付勢力により、ノズルニードル１がシート面１０方向に付勢され、シート部１５がシート面１０の弁座に着座すると燃料噴射は終了する。   Further, the nozzle hole cross-sectional area (the nozzle hole diameter) of the nozzle hole expanding channel 35 extending from the nozzle hole minimum diameter (φD1) of the small diameter nozzle hole inlet part 31 to the nozzle hole maximum diameter (φD3) of the nozzle hole expanding part 33 is Because of rapid expansion, the fuel flow is disturbed when passing through the nozzle hole expansion flow path 35, and cavities (bubbles) serving as the core of atomization of fuel spray after fuel injection are generated. Furthermore, the nozzle hole maximum diameter (φD3) of the nozzle hole expanding portion 33 is changed from the nozzle hole maximum diameter (φD3) of the nozzle hole expanding portion 33 beyond the nozzle hole maximum diameter (φD3) of the nozzle hole expanding channel 35. The fuel flow that has flowed into the nozzle hole reducing flow path 36 reaches the nozzle hole cross-sectional area (nozzle hole diameter) of the nozzle hole reducing flow path 36 so that it gradually narrows toward the nozzle hole outlet 32 again. To converge. Then, the fuel flows out from the injection hole outlet 32 of the injection hole 9 and is injected into the combustion chamber of each cylinder of the engine. When the fuel pressure from the fuel injection pump approaches the end, the fuel pressure in the fuel passage 5 decreases, so that the nozzle needle 1 is biased toward the seat surface 10 by the biasing force of the spring, and the seat portion 15 is When seated on the valve seat of the seat surface 10, the fuel injection is terminated.

［実施例１の効果］
以上のように、本実施例のディーゼルエンジン用の燃料噴射ノズルにおいては、ノズルボデー２の円頂部２４の内壁面から噴孔部９の噴孔入口部３１の噴孔最小径に至る部分にＲ形状の面取り部３４を設けているので、燃料通路１４から噴孔部９の噴孔入口部３１に燃料流が入る時に噴孔部９の噴孔軸線方向に急激に曲げられるが、その曲がり圧力損失を低減することができる。 [Effect of Example 1]
As described above, in the fuel injection nozzle for the diesel engine of the present embodiment, an R shape is formed in the portion from the inner wall surface of the circular top portion 24 of the nozzle body 2 to the minimum diameter of the injection hole inlet 31 of the injection hole portion 9. Since the chamfered portion 34 is provided, when the fuel flow enters the nozzle hole inlet 31 of the nozzle hole 9 from the fuel passage 14, it is suddenly bent in the nozzle hole axial direction of the nozzle hole 9. Can be reduced.

また、小径の噴孔入口部３１の噴孔最小径（φＤ１）から噴孔拡大部３３の噴孔最大径（φＤ３）に至る噴孔拡大流路３５の噴孔断面積（噴孔径）を急拡大とすることで、噴孔拡大流路３５内を通過する際に燃料流が乱れ、キャビティ（気泡）を大量に生成できるので、燃料噴射の直後から燃料噴霧の微粒化を促進することができる。この結果、燃料の着火性が向上して良好な燃焼が確保されるため、エンジンの排気ガス中に含まれる有害成分（ディーゼルパティキュレート）や黒煙の生成量を低減できる。   Further, the injection hole cross-sectional area (injection hole diameter) of the injection hole expansion passage 35 extending from the injection hole minimum diameter (φD1) of the injection hole inlet portion 31 with a small diameter to the injection hole maximum diameter (φD3) of the injection hole expansion portion 33 By enlarging, since the fuel flow is disturbed when passing through the nozzle hole enlarged flow path 35 and a large amount of cavities (bubbles) can be generated, atomization of fuel spray can be promoted immediately after fuel injection. . As a result, since the ignitability of the fuel is improved and good combustion is ensured, the amount of harmful components (diesel particulates) and black smoke contained in the exhaust gas of the engine can be reduced.

さらに、噴孔拡大部３３の噴孔最大径（φＤ３）から小径の噴孔出口部３２の噴孔最小径（φＤ２）に至る噴孔縮小流路３６の噴孔断面積（噴孔径）が緩やかに狭くなるため、噴孔縮小流路３６内を通過する燃料流が噴孔出口部３２に向かってもう一度噴孔軸線方向に収束される。これにより、噴孔部９の噴孔出口部３２の近傍から、燃料噴霧の外輪は霧化・分散することで、太い燃料噴霧を形成すると共に、軸線中央部はより遠くに飛ぶようになる。この結果、噴孔部９の噴孔出口部３２からエンジンの各気筒の燃焼室内に噴射される燃料噴霧は、太くて長い燃料噴霧となり、燃料噴霧を分散させることなく、エンジンの各気筒の燃焼室内の狙った方向に噴射され、且つエンジンの各気筒の燃焼室内全体に行き渡る。   Further, the nozzle hole cross-sectional area (nozzle hole diameter) of the nozzle hole reducing passage 36 from the nozzle hole maximum diameter (φD3) of the nozzle hole expanding portion 33 to the nozzle hole minimum diameter (φD2) of the small diameter nozzle hole outlet portion 32 is gentle. Therefore, the fuel flow passing through the nozzle hole reducing flow path 36 is once again converged toward the nozzle hole outlet portion 32 in the nozzle hole axis direction. As a result, the outer ring of fuel spray is atomized and dispersed from the vicinity of the nozzle hole outlet 32 of the nozzle hole 9 to form a thick fuel spray, and the center part of the axial line can fly farther. As a result, the fuel spray injected into the combustion chamber of each cylinder of the engine from the nozzle hole outlet portion 32 of the nozzle hole 9 becomes a thick and long fuel spray, and combustion of each cylinder of the engine is performed without dispersing the fuel spray. The fuel is injected in the target direction in the room and reaches the entire combustion chamber of each cylinder of the engine.

したがって、噴孔部９の噴孔出口部３２からエンジンの各気筒の燃焼室内に噴射される燃料噴霧の微粒化の促進と燃料噴霧の高貫通力とを両立させることができるので、エンジンの各気筒の燃焼室内の空気利用率を向上することができ、良好な燃焼を確保できる。これにより、エンジンの各気筒の燃焼室内の燃焼状態を更に改善できるので、エンジンの排気ガス性能を更に向上でき、且つエンジン出力を向上することができる。よって、エンジンの排気ガスを浄化することができ、且つ低燃費化を図ることができる。   Therefore, since the atomization of the fuel spray injected from the nozzle hole outlet portion 32 of the nozzle hole portion 9 into the combustion chamber of each cylinder of the engine can be made compatible with the high penetration force of the fuel spray, each of the engine The air utilization rate in the combustion chamber of the cylinder can be improved, and good combustion can be ensured. Thereby, since the combustion state in the combustion chamber of each cylinder of the engine can be further improved, the exhaust gas performance of the engine can be further improved and the engine output can be improved. Therefore, the exhaust gas of the engine can be purified and fuel consumption can be reduced.

図５は本発明の実施例２を示したもので、ノズルボデーの噴孔流路の形状を示した図である。本実施例では、ノズルボデー２の円頂部２４の内壁面から噴孔部９の噴孔入口部３１の噴孔最小径（φＤ１）に至る部分に、燃料通路１４から噴孔入口部３１に燃料流が入る時の曲がり圧力損失を低減するためにテーパ形状の面取りが施された面取り部３７が設けられている。この場合には、噴孔部９の噴孔入口部３１の噴孔断面積（噴孔最小径：φＤ１）が、実施例１よりも大きくなるので、燃料流の流速が遅くなり、摩擦損失を低減することができる。その他の作用および効果は実施例１と同様である。   FIG. 5 shows a second embodiment of the present invention and is a diagram showing the shape of the nozzle hole passage of the nozzle body. In the present embodiment, the fuel flow from the fuel passage 14 to the nozzle hole inlet 31 is performed from the inner wall surface of the circular top 24 of the nozzle body 2 to the nozzle hole minimum diameter (φD1) of the nozzle hole inlet 31 of the nozzle hole 9. A chamfered portion 37 having a tapered chamfering is provided in order to reduce bending pressure loss when entering. In this case, the injection hole cross-sectional area (minimum injection hole diameter: φD1) of the injection hole inlet 31 of the injection hole 9 is larger than that of the first embodiment, so that the flow rate of the fuel flow is reduced and the friction loss is reduced. Can be reduced. Other operations and effects are the same as those of the first embodiment.

図６は本発明の実施例３を示したもので、ノズルボデーの噴孔流路の形状を示した図である。本実施例では、噴孔部９の噴孔入口部３１に、噴孔最小径（φＤ１）が同一のストレート部３１ａを設けている。この場合には、噴孔入口部３１をストレートにすることで、噴孔入口部３１のＲ形状の面取り部３４の加工精度を出し易くなる。その他の作用および効果は実施例１と同様である。   FIG. 6 shows Embodiment 3 of the present invention and is a view showing the shape of the nozzle hole passage of the nozzle body. In this embodiment, a straight portion 31a having the same minimum nozzle hole diameter (φD1) is provided in the nozzle hole inlet 31 of the nozzle hole 9. In this case, by making the injection hole inlet 31 straight, it becomes easy to obtain the machining accuracy of the R-shaped chamfer 34 of the injection hole inlet 31. Other operations and effects are the same as those of the first embodiment.

［変形例］
本実施例では、本発明の燃料噴射ノズルを、列型燃料噴射ポンプや分配型燃料噴射ポンプ等の燃料噴射ポンプから油溜り室４および燃料通路５内に直接圧送され、燃料通路５内の燃料圧力がスプリング等のニードル付勢手段の付勢力よりも大きくなるとノズルニードル１が開弁して、エンジンの各気筒の燃焼室内に燃料噴射する内燃機関用燃料噴射装置（エンジン制御システム）に使用される燃料噴射ノズルに適用した例を説明したが、本発明の燃料噴射ノズルを、列型燃料噴射ポンプや分配型燃料噴射ポンプ等の燃料噴射ポンプから油溜り室４および燃料通路５内に直接圧送され、燃料通路５内の燃料圧力が第１、第２スプリング等の第１、第２ニードル付勢手段の付勢力よりも大きくなるとノズルニードル１が開弁して、エンジンの各気筒の燃焼室内に燃料噴射する内燃機関用燃料噴射装置（エンジン制御システム）に使用される燃料噴射ノズルに適用しても良い。 [Modification]
In this embodiment, the fuel injection nozzle of the present invention is directly pumped from the fuel injection pump such as the row type fuel injection pump or the distribution type fuel injection pump into the oil sump chamber 4 and the fuel passage 5, and the fuel in the fuel passage 5 is When the pressure becomes larger than the urging force of a needle urging means such as a spring, the nozzle needle 1 opens and is used in a fuel injection device (engine control system) for an internal combustion engine that injects fuel into the combustion chamber of each cylinder of the engine. However, the fuel injection nozzle of the present invention is directly pumped from the fuel injection pump such as the row type fuel injection pump or the distribution type fuel injection pump into the oil reservoir 4 and the fuel passage 5. When the fuel pressure in the fuel passage 5 becomes larger than the urging force of the first and second needle urging means such as the first and second springs, the nozzle needle 1 is opened, and each gas of the engine Fuel injection device for an internal combustion engine for fuel injection into the combustion chamber may be applied to a fuel injection nozzle used in the (engine control system).

また、本発明を、燃料噴射ポンプ（燃料供給ポンプ、高圧供給ポンプ、サプライポンプ）から圧送された高圧燃料をコモンレール（蓄圧配管）内に蓄圧し、このコモンレール内に蓄圧した高圧燃料を、エンジンの各気筒の燃焼室内に噴射供給する蓄圧式燃料噴射装置（コモンレール式燃料噴射システム、エンジン制御システム）に使用されるインジェクタ（例えば電磁式燃料噴射弁）の燃料噴射ノズルに適用しても良い。この場合には、図示しない電磁式アクチュエータ（ノズルニードル１を開弁方向に駆動するニードル駆動手段）としての電磁弁を開弁駆動することによってノズルニードル１と連動して動作するコマンドピストンの背後（例えばノズルホルダーの後端部）に形成される背圧制御室（図示せず）内の燃料圧力を制御することにより、ノズルニードル１が軸方向（図示上下方向）に往復移動するように構成される。なお、インジェクタとして、圧電方式の燃料噴射弁を採用しても良い。また、本発明の燃料噴射ノズルを、ガソリンエンジン用のフューエルインジェクタの燃料噴射ノズルに適用しても良い。   Further, according to the present invention, high-pressure fuel pumped from a fuel injection pump (fuel supply pump, high-pressure supply pump, supply pump) is accumulated in a common rail (pressure accumulation pipe), and the high-pressure fuel accumulated in the common rail is stored in the engine. You may apply to the fuel-injection nozzle of the injector (for example, electromagnetic fuel injection valve) used for the pressure accumulation type fuel-injection apparatus (a common rail type fuel-injection system, an engine control system) which injects and supplies in the combustion chamber of each cylinder. In this case, the back of the command piston that operates in conjunction with the nozzle needle 1 by opening the electromagnetic valve as an electromagnetic actuator (needle driving means for driving the nozzle needle 1 in the valve opening direction) (not shown). For example, the nozzle needle 1 is configured to reciprocate in the axial direction (vertical direction in the drawing) by controlling the fuel pressure in a back pressure control chamber (not shown) formed in the rear end portion of the nozzle holder. The A piezoelectric fuel injection valve may be employed as the injector. Further, the fuel injection nozzle of the present invention may be applied to a fuel injection nozzle of a fuel injector for a gasoline engine.

本実施例では、本発明を、直接噴射式ディーゼルエンジンのシリンダヘッドに取り付けて燃料をエンジンの各気筒の燃焼室内に直接噴射する直接噴射タイプの燃料噴射ノズルに適用した例を説明したが、本発明を、副燃焼室式ディーゼルエンジンのシリンダヘッドに取り付けて燃料をエンジンの各気筒の副燃焼室内に噴射するタイプの燃料噴射ノズルに適用しても良い。また、本実施例では、複数の噴孔流路の断面形状を円形状としたが、複数の噴孔流路の断面形状を多角形状、長円形状、楕円形状としても良い。また、本実施例では、ノズルニードル１のシート部１５よりも先端側を単純な円錐面形状（先端円錐面１６）としたが、複数段の円錐面形状としても良い。また、ノズルボデー２のシート面１０を単純な円錐面形状としたが、ノズルニードル１のシート部（稜線、エッジ部）１５がシート面１０側のエッジ部に接触しなければ、複数段の円錐面形状としても良い。   In this embodiment, an example in which the present invention is applied to a direct injection type fuel injection nozzle that is attached to a cylinder head of a direct injection type diesel engine and directly injects fuel into a combustion chamber of each cylinder of the engine has been described. The invention may be applied to a fuel injection nozzle that is attached to a cylinder head of a sub-combustion chamber type diesel engine and injects fuel into the sub-combustion chamber of each cylinder of the engine. In the present embodiment, the cross-sectional shape of the plurality of nozzle hole channels is circular, but the cross-sectional shape of the plurality of nozzle hole channels may be polygonal, elliptical, or elliptical. In the present embodiment, the tip side of the nozzle needle 1 with respect to the seat portion 15 has a simple conical surface shape (tip conical surface 16), but it may have a plurality of conical surface shapes. Further, the sheet surface 10 of the nozzle body 2 has a simple conical surface shape. However, if the sheet portion (ridge line, edge portion) 15 of the nozzle needle 1 does not contact the edge portion on the sheet surface 10 side, a plurality of conical surfaces are formed. It is good also as a shape.

本実施例では、噴孔入口部３１の噴孔最小径から噴孔拡大部３３の噴孔最大径に至る噴孔拡大流路３５を、噴孔入口部３１の噴孔最小径から噴孔拡大部３３の噴孔最大径に向かって噴孔断面積（噴孔径）が次第に大きくなるように円錐台形状に形成したが、噴孔拡大流路３５を、噴孔入口部３１の噴孔最小径から噴孔拡大部３３の噴孔最大径に向かって噴孔断面積（噴孔径）が次第に大きくなるように所定の曲率を持つように湾曲させても良い。また、本実施例では、噴孔部９の噴孔入口部３１を、内部にサックボリューム（サック室）２５が形成される円頂部２４の内壁面で開口させているが、噴孔部９の噴孔入口部３１を、ノズルボデー２の円錐形状の内壁面（シート面１０）で開口させても良い。   In the present embodiment, the nozzle hole expanding channel 35 extending from the nozzle hole minimum diameter of the nozzle hole inlet part 31 to the nozzle hole maximum diameter of the nozzle hole expanding part 33 is expanded from the nozzle hole minimum diameter of the nozzle hole inlet part 31. The nozzle hole is formed in a truncated cone shape so that the nozzle hole cross-sectional area (nozzle hole diameter) gradually increases toward the nozzle hole maximum diameter of the portion 33. Alternatively, the nozzle hole may be curved so as to have a predetermined curvature so that the nozzle hole cross-sectional area (nozzle hole diameter) gradually increases from the nozzle hole expanding portion 33 toward the nozzle hole maximum diameter. In this embodiment, the nozzle hole inlet 31 of the nozzle hole 9 is opened at the inner wall surface of the circular top part 24 in which the sac volume (sack chamber) 25 is formed. The nozzle hole inlet 31 may be opened by the conical inner wall surface (sheet surface 10) of the nozzle body 2.

本実施例では、噴孔拡大部３３の噴孔最大径から噴孔出口部３２の噴孔最小径に至る噴孔縮小流路３６を、噴孔拡大部３３の噴孔最大径から噴孔出口部３２の噴孔最小径に向かって噴孔断面積（噴孔径）が次第に小さくなるように円錐台形状に形成したが、噴孔縮小流路３６を、噴孔拡大部３３の噴孔最大径から噴孔出口部３２の噴孔最小径に向かって噴孔断面積（噴孔径）が次第に小さくなるように所定の曲率を持つように湾曲させても良い。また、噴孔拡大部３３に、実施例３の噴孔入口部３１のストレート部３１ａのように噴孔最大径（φＤ３）が同一のストレート部を設けても良い。   In this embodiment, the nozzle hole reducing flow path 36 extending from the nozzle hole maximum diameter of the nozzle hole expanding part 33 to the nozzle hole minimum diameter of the nozzle hole outlet part 32 is changed from the nozzle hole maximum diameter of the nozzle hole expanding part 33 to the nozzle hole outlet. The nozzle hole is formed in a truncated cone shape such that the nozzle hole cross-sectional area (hole diameter) gradually decreases toward the nozzle hole minimum diameter of the portion 32. Alternatively, the nozzle hole may be curved so as to have a predetermined curvature so that the nozzle hole cross-sectional area (nozzle hole diameter) gradually decreases from the nozzle hole outlet portion 32 toward the nozzle hole minimum diameter. Further, the nozzle hole expanding part 33 may be provided with a straight part having the same nozzle hole maximum diameter (φD3) like the straight part 31a of the nozzle hole inlet part 31 of the third embodiment.

本実施例では、燃料噴霧の微粒化の促進と比べて燃料噴霧の高貫通力を重視するために、φＤ１＞φＤ２の関係を満足するように、噴孔入口部３１の噴孔最小径（φＤ１）および噴孔出口部３２の噴孔最小径（φＤ２）を設定しているが、燃料噴霧の高貫通力と比べて燃料噴霧の微粒化の促進を重視するために、φＤ１＜φＤ２の関係を満足するように、噴孔入口部３１の噴孔最小径（φＤ１）および噴孔出口部３２の噴孔最小径（φＤ２）を設定しても良い。また、φＤ１＝φＤ２の関係を満足するように、噴孔入口部３１の噴孔最小径（φＤ１）および噴孔出口部３２の噴孔最小径（φＤ２）を設定しても良い。   In the present embodiment, in order to emphasize the high penetrating force of the fuel spray as compared with the promotion of atomization of the fuel spray, the minimum nozzle hole diameter (φD1) of the nozzle hole inlet 31 is satisfied so as to satisfy the relationship of φD1> φD2. ) And the nozzle hole minimum diameter (φD2) of the nozzle hole outlet portion 32. In order to emphasize the promotion of atomization of the fuel spray compared with the high penetration force of the fuel spray, the relationship of φD1 <φD2 is set. The nozzle hole minimum diameter (φD1) of the nozzle hole inlet portion 31 and the nozzle hole minimum diameter (φD2) of the nozzle hole outlet portion 32 may be set so as to satisfy. Further, the minimum injection hole diameter (φD1) of the injection hole inlet 31 and the minimum injection hole diameter (φD2) of the injection hole outlet 32 may be set so as to satisfy the relationship of φD1 = φD2.

燃料噴射ノズルの全体構成を示した断面図である（実施例１）。It is sectional drawing which showed the whole structure of the fuel-injection nozzle (Example 1). 燃料噴射ノズルの主要構成を示した断面図である（実施例１）。It is sectional drawing which showed the main structures of the fuel-injection nozzle (Example 1). ノズルボデーの噴孔部を拡大した断面図である（実施例１）。It is sectional drawing which expanded the nozzle hole part of the nozzle body (Example 1). ノズルボデーの噴孔流路の形状を示した断面図である（実施例１）。It is sectional drawing which showed the shape of the nozzle hole flow path of a nozzle body (Example 1). ノズルボデーの噴孔流路の形状を示した断面図である（実施例２）。(Example 2) which is sectional drawing which showed the shape of the nozzle hole flow path of a nozzle body. ノズルボデーの噴孔流路の形状を示した断面図である（実施例３）。(Example 3) which is sectional drawing which showed the shape of the nozzle hole flow path of a nozzle body. ノズルボデーの噴孔流路の形状を示した断面図である（従来の技術）。It is sectional drawing which showed the shape of the nozzle hole flow path of a nozzle body (conventional technique). ノズルボデーの噴孔流路の形状を示した断面図である（従来の技術）。It is sectional drawing which showed the shape of the nozzle hole flow path of a nozzle body (conventional technique).

符号の説明Explanation of symbols

１ ノズルニードル
２ ノズルボデー
９ 噴孔部
１０ シート面
１５ シート部
１６ 先端円錐面
２４ 円頂部
２５ サックボリューム（サック室）
３１ 噴孔入口部
３２ 噴孔出口部
３３ 噴孔拡大部
３４ 面取り部
３５ 噴孔拡大流路
３６ 噴孔縮小流路
３７ 面取り部
３１ａ ストレート部 DESCRIPTION OF SYMBOLS 1 Nozzle needle 2 Nozzle body 9 Injection hole part 10 Sheet | seat surface 15 Sheet | seat part 16 Tip conical surface 24 Round top part 25 Suck volume (sack chamber)
DESCRIPTION OF SYMBOLS 31 Injection hole entrance part 32 Injection hole exit part 33 Injection hole expansion part 34 Chamfering part 35 Injection hole expansion flow path 36 Injection hole reduction flow path 37 Chamfering part 31a Straight part

Claims (4)

ノズルニードルを摺動自在に保持する筒状のノズルボデーを備え、
このノズルボデーの先端部に、前記ノズルボデーの内壁で開口した噴孔入口部と前記ノズルボデーの外壁で開口した噴孔出口部とを連通する噴孔部を有し、
前記ノズルニードルが前記ノズルボデーの弁座部より離座した際に、前記ノズルボデー内部に供給された燃料を、前記噴孔部を介して内燃機関の気筒の燃焼室内に噴射する燃料噴射ノズルにおいて、
前記噴孔部は、前記噴孔入口部と前記噴孔出口部との間に噴孔拡大部を有し、
前記噴孔入口部の噴孔最小径をφＤ１、
前記噴孔出口部の噴孔最小径をφＤ２、
前記噴孔拡大部の噴孔最大径をφＤ３としたとき、
φＤ１＜φＤ３で、且つφＤ２＜φＤ３
の関係を満足し、
且つ、前記噴孔部は、前記噴孔入口部から前記噴孔拡大部に向かって噴孔断面積が次第に大きくなるように形成された噴孔拡大流路、および前記噴孔拡大部から前記噴孔出口部に向かって噴孔断面積が次第に小さくなるように形成された噴孔縮小流路を有し、
前記噴孔拡大流路の噴孔軸線方向の長さをＬ１、
前記噴孔縮小流路の噴孔軸線方向の長さをＬ２としたとき、
Ｌ１＜Ｌ２
の関係を満足していることを特徴とする燃料噴射ノズル。 It has a cylindrical nozzle body that slidably holds the nozzle needle,
At the tip of this nozzle body, it has a nozzle hole part that communicates with a nozzle hole inlet part opened at the inner wall of the nozzle body and a nozzle hole outlet part opened at the outer wall of the nozzle body,
In the fuel injection nozzle for injecting the fuel supplied into the nozzle body into the combustion chamber of the cylinder of the internal combustion engine through the nozzle hole when the nozzle needle is separated from the valve seat of the nozzle body,
The nozzle hole part has a nozzle hole enlarged part between the nozzle hole inlet part and the nozzle hole outlet part,
The minimum nozzle hole diameter of the nozzle hole inlet is φD1,
The minimum diameter of the nozzle hole at the nozzle hole outlet is φD2,
When the maximum diameter of the nozzle hole enlarged portion is φD3,
φD1 <φD3 and φD2 <φD3
Satisfy the relationship,
In addition, the nozzle hole section includes a nozzle hole expanding channel formed so that a nozzle hole cross-sectional area gradually increases from the nozzle hole inlet section toward the nozzle hole expanding section, and the nozzle hole section from the nozzle hole expanding section. It has a nozzle hole reduction channel formed so that the nozzle hole cross-sectional area gradually decreases toward the hole outlet part,
The length of the nozzle hole expansion channel in the nozzle hole axial direction is L1,
When the length of the nozzle hole axial direction of the nozzle hole reducing channel is L2,
L1 <L2
A fuel injection nozzle characterized by satisfying the above relationship . 請求項１に記載の燃料噴射ノズルにおいて、
前記ノズルボデー内部には、前記ノズルニードルが前記弁座部より離座した際に、前記ノズルボデーの内壁と前記ノズルニードルとの間に、前記弁座部から前記噴孔部に至る燃料通路が設けられており、
前記噴孔部の噴孔軸線方向は、前記燃料通路を流れる燃料の流れ方向に対して所定の傾斜角度だけ傾いて配置されていることを特徴とする燃料噴射ノズル。 The fuel injection nozzle according to claim 1,
A fuel passage extending from the valve seat portion to the nozzle hole portion is provided between the inner wall of the nozzle body and the nozzle needle when the nozzle needle is separated from the valve seat portion. And
The fuel injection nozzle according to claim 1, wherein an injection hole axial direction of the injection hole portion is inclined with respect to a flow direction of the fuel flowing through the fuel passage by a predetermined inclination angle . 請求項２に記載の燃料噴射ノズルにおいて、
前記噴孔部は、
前記ノズルボデーの内壁から前記噴孔入口部の噴孔最小径に至る部分に、面取りが施された面取り部を設けていることを特徴とする燃料噴射ノズル。 The fuel injection nozzle according to claim 2 ,
The nozzle hole part is
A fuel injection nozzle, wherein a chamfered portion is provided in a portion from an inner wall of the nozzle body to a nozzle hole minimum diameter of the nozzle hole inlet portion . 請求項１ないし請求項３のうちのいずれか１つに記載の燃料噴射ノズルにおいて、
前記ノズルボデーの先端部には、内部にサックボリュームを形成する略半球状の円頂部が設けられ、
前記円頂部には、略同一円周上に前記噴孔部が複数配置されていることを特徴とする燃料噴射ノズル。 The fuel injection nozzle according to any one of claims 1 to 3 ,
The tip of the nozzle body is provided with a substantially hemispherical top that forms a sac volume inside,
The fuel injection nozzle according to claim 1, wherein a plurality of the nozzle hole portions are arranged on substantially the same circumference at the circular top portion .
JP2004132742A 2004-04-28 2004-04-28 Fuel injection nozzle Expired - Fee Related JP4127237B2 (en)

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