JPH06185430A

JPH06185430A - Fuel injection valve

Info

Publication number: JPH06185430A
Application number: JP35355992A
Authority: JP
Inventors: Isamu Sasao; 勇笹尾
Original assignee: Keihin Seiki Manufacturing Co Ltd
Current assignee: Keihin Corp
Priority date: 1992-12-14
Filing date: 1992-12-14
Publication date: 1994-07-05
Anticipated expiration: 2012-09-03
Also published as: JP2648691B2

Abstract

PURPOSE:To improve atomization of fuel which is injected from a fuel injection valve. CONSTITUTION:A cylindrical cover 10 is opposed to and arranged on an end face 9D of a valve body housing 9 whose injection port 9A is opened. The cover 10 is provided with an air-fuel mixture forming port 10D which has one end opened to the end face 9D of the cover 10 and the other end is opened correspondingly to the injection port 9A of the valve body housing 9, and to which an end of a needle part 6A of the vale body 6 can be inserted, and an air suction passage 10E which has one end opened to the air-fuel mixture forming port 10D and the other end opened to the end face 10C or an outer peripheral side surface 10F of the cover 10. The needle part 6A of the valve body 6 is provided with an air passage 11 which has one end opened to an end face 6C of the needle part 6A and the other end opened to an outer peripheral side surface 6D of the needle part 6A.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は四輪車、二輪車、等の内
燃機関の燃料噴射装置に用いられる燃料噴射弁に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve used in a fuel injection device for an internal combustion engine such as a four-wheeled vehicle, a two-wheeled vehicle and the like.

【０００２】[0002]

【従来の技術】内燃機関の燃料供給装置として、燃費の
向上、排気ガスの浄化の点より燃料噴射弁を用いた燃料
噴射装置が良く用いられる。第１の従来例として、実公
平４−１３４１７号公報がある。これは、燃料噴孔の下
流側の合流部に、該合流部内と燃料噴射弁先端部の外気
とを連通する外気圧導入孔を設けたものである。又、第
２の従来例として実公昭４８−３８０８４号公報があ
る。これは、噴射弁保持器内に構成した外開式噴射弁部
の燃料下流に、該噴射弁部を覆う保護筒を固設し、外開
式噴射弁部を介して噴射弁保持器内の燃料導入孔と連通
する噴霧流通路を保護筒に穿設し、更に噴霧流通路の中
央部に絞り部を設けるとともに絞り部に噴霧流通路を連
通する空気吸入孔を穿設したものである。又、第３の従
来例として特開昭５９−７７０７４号公報がある。これ
は、噴射ノズルがノズル放出口から燃焼室内に延びる少
なくとも１個の空気通路の開口につながるエジェクタ取
付部によって包まれ、噴射ノズルから噴射された燃料噴
射は空気通路からの空気を混入させたものである。2. Description of the Related Art As a fuel supply device for an internal combustion engine, a fuel injection device using a fuel injection valve is often used in terms of improving fuel efficiency and purifying exhaust gas. As a first conventional example, there is JP-B-4-13417. In this configuration, an external pressure introducing hole is provided at a merging portion on the downstream side of the fuel injection hole, which communicates the inside of the merging portion with the outside air at the tip of the fuel injection valve. A second conventional example is Japanese Utility Model Publication No. 48-38084. This is because a protective cylinder that covers the injection valve portion is fixedly provided downstream of the fuel of the externally opened injection valve portion configured in the injection valve holder, and the inside of the injection valve holder is provided through the externally opened injection valve portion. The protective cylinder is provided with a spray passage that communicates with the fuel introduction hole, and a throttle portion is provided at the center of the spray passage, and an air suction hole is formed in the throttle portion so as to communicate the spray passage. Also, as a third conventional example, there is JP-A-59-77074. This is that the injection nozzle is wrapped by an ejector mounting portion connected to the opening of at least one air passage extending from the nozzle discharge port into the combustion chamber, and the fuel injection injected from the injection nozzle is a mixture of air from the air passage. Is.

【０００３】[0003]

【発明が解決しようとする課題】かかる従来の燃料噴射
弁にあっては、燃料噴射弁から噴射される燃料の微粒化
が充分に行なわれない。まず第１の従来例にあっては、
燃料噴孔によって所定の流量に計量された燃料はアダプ
タ通路としての合流部内に入り各噴射燃料通路に分岐さ
れて吸気管に向けて噴射される。ここで燃料噴孔からの
燃料通路は合流部で通路面積が拡大されることによって
燃料噴孔から噴射される燃料の流速は弱められる。一
方、合流部には外気圧導入孔を設けたことによって外気
圧（空気）が導入されることになるが燃料の流速が弱め
られたことによって燃料と空気との充分なる混合が行な
われるものでなく燃料の微粒化を達成できないものであ
る。In such a conventional fuel injection valve, the fuel injected from the fuel injection valve is not sufficiently atomized. First, in the first conventional example,
The fuel metered to a predetermined flow rate by the fuel injection holes enters the merging portion as the adapter passage, is branched into each injection fuel passage, and is injected toward the intake pipe. Here, since the passage area of the fuel passage from the fuel injection hole is enlarged at the merging portion, the flow velocity of the fuel injected from the fuel injection hole is weakened. On the other hand, since the outside air pressure (air) is introduced by providing the outside air pressure introduction hole in the merging portion, the fuel and the air are sufficiently mixed because the flow velocity of the fuel is weakened. Without it, it is impossible to achieve atomization of fuel.

【０００４】又、第２の従来例によると、噴射された燃
料に対して空気吸入孔より充分なる空気を供給できるも
のでなく良好な燃料の霧化を行なうことは困難である。
すなわち、気化器の絞り部の如く、絞り部の下流側の噴
霧流通路より負圧をかけた際において絞り部には高い負
圧が発生し、空気吸入孔より空気を絞り部に対して充分
に吸入し得るものであるが、絞り部の上流側の噴霧流通
路より加圧された燃料を噴射した際においては絞り部に
対して噴射圧が作用して絞り部に対して大きな負圧を生
起させることが困難となるもので空気吸入孔より絞り部
内に充分に空気を吸入できない。空気吸入孔より噴射さ
れた燃料が逆に噴出する恐れがある。Further, according to the second conventional example, sufficient air cannot be supplied to the injected fuel from the air suction hole, and it is difficult to atomize the fuel satisfactorily.
That is, when a negative pressure is applied from the spray flow passage on the downstream side of the throttle portion, like the throttle portion of the carburetor, a high negative pressure is generated in the throttle portion, and air is sufficiently supplied to the throttle portion from the air suction hole. However, when the pressurized fuel is injected from the spray flow passage on the upstream side of the throttle, the injection pressure acts on the throttle and a large negative pressure is applied to the throttle. Since it is difficult to generate the air, the air cannot be sufficiently sucked into the throttle portion from the air suction hole. The fuel injected from the air intake hole may be ejected in the opposite direction.

【０００５】又、第３の従来例によると、燃料通路から
噴射された燃料は、中空室を介してエジェクター通路に
供給されて燃焼室内に供給されるがこの時エジェクター
通路内に横方向空気通路より空気を吸入して燃料と混合
される。然しながらエジェクター通路は単なる絞り通路
であって噴射された燃料が自由に拡散し得ることからエ
ジェクター通路内を流れる噴射燃料の流速を大きく上昇
させることが困難である。これによると、エジェクター
通路の上流側に開口する空気通路に生起する負圧力を大
きく上昇させることは望めないもので、空気通路より充
分なる空気の吸入と、燃料中に空気を混入させて燃料を
良好に微粒化させることが困難である。本従来例にあっ
ては空気通路を流れる空気を高度に圧縮したことによっ
てはじめて燃料と空気との混合が達成できたものであ
る。Further, according to the third conventional example, the fuel injected from the fuel passage is supplied to the ejector passage through the hollow chamber and then to the combustion chamber. At this time, the lateral air passage is provided in the ejector passage. More air is sucked in and mixed with fuel. However, since the ejector passage is a mere throttle passage and the injected fuel can freely diffuse, it is difficult to greatly increase the flow velocity of the injected fuel flowing in the ejector passage. According to this, it is not possible to greatly increase the negative pressure generated in the air passage opening to the upstream side of the ejector passage, and sufficient intake of air from the air passage and mixing of air into the fuel to remove the fuel It is difficult to make the particles fine. In this conventional example, the mixture of fuel and air can be achieved only by highly compressing the air flowing through the air passage.

【０００６】本発明は前記課題に鑑み成されたもので、
燃料噴射弁より噴射される燃料に空気が充分に混合され
て燃料の微粒化の良好な燃料噴射弁を提供することを目
的とする。The present invention has been made in view of the above problems,
An object of the present invention is to provide a fuel injection valve in which air is sufficiently mixed with fuel injected from the fuel injection valve and the atomization of the fuel is excellent.

【０００７】[0007]

【課題を解決する為の手段】本発明になる燃料噴射弁は
前記課題を達成する為に先端に噴射孔が開口し、前記噴
射孔と内部に設けられた弁室とを弁座にて接続する弁体
ハウジングと、弁体ハウジングの後端に連結された本体
ハウジングと、弁体ハウジングの弁室内に軸方向移動自
在に配置され、その先端部に噴射孔内に挿通されるとと
もに噴射孔より突出するニードル部と弁座に着座可能な
る弁部とを有する弁体と、本体ハウジング内にあって弁
体を軸方向に駆動する為のソレノイドと、を備えてなる
燃料噴射弁において、弁体ハウジングの先端面に筒状の
カバーを対向配置し、前記カバーには、一端がカバーの
先端面に開口し、他端が弁体ハウジングの噴射孔に対応
して開口するとともに弁体のニードル部の先端部を挿入
し得る混合気形成孔と、一端が混合気形成孔に開口し、
他端がカバーの先端面又は外周側面に開口する空気吸入
路とを設け、一方、弁体のニードル部に、一端がニード
ル部の先端面に開口し、他端がニードル部の外周側面に
開口する空気通路を形成したものである。In order to achieve the above-mentioned object, a fuel injection valve according to the present invention has an injection hole at its tip, and the injection hole and a valve chamber provided therein are connected by a valve seat. A valve body housing, a main body housing connected to the rear end of the valve body housing, and an axially movable body in a valve chamber of the valve body housing. A fuel injection valve comprising a valve body having a protruding needle portion and a valve portion capable of being seated on a valve seat, and a solenoid for axially driving the valve body in a main body housing. A cylindrical cover is arranged opposite to the front end surface of the housing, and one end of the cover is opened at the front end surface of the cover and the other end is opened corresponding to the injection hole of the valve body housing, and the needle portion of the valve body is also opened. Mixture formation that can insert the tip of When one end opening to the mixture formation hole,
The other end is provided with an air suction passage that opens to the tip surface or outer peripheral side surface of the cover, while the needle portion of the valve body has one end open to the tip end surface of the needle portion and the other end opens to the outer peripheral side surface of the needle portion. The air passage is formed.

【０００８】[0008]

【作用】噴射孔より噴射される燃料は、混合気形成孔と
弁体のニードル部の外周との間に形成される環状の間隙
内に噴射される。このとき、前記間隙内を高速なる噴射
燃料が流下することによって間隙内に大なる負圧が生起
する。この負圧によると、空気吸入路より混合気形成孔
内に空気を吸入し、この空気が間隙内を流下する燃料中
に混合される。一方、環状の間隙を流下する噴射燃料は
ニードル部の外周側面にも大きな負圧を生起させる。こ
の負圧によるとニードル部の先端面より空気通路内に空
気を吸入し、この空気がニードル部の外周側面より噴射
される燃料中に混合される。The fuel injected from the injection hole is injected into the annular gap formed between the mixture forming hole and the outer periphery of the needle portion of the valve body. At this time, a high negative pressure is generated in the gap by the high-speed injected fuel flowing down in the gap. According to this negative pressure, air is sucked into the air-fuel mixture forming hole from the air suction passage, and this air is mixed with the fuel flowing down in the gap. On the other hand, the injected fuel flowing down the annular gap also causes a large negative pressure on the outer peripheral side surface of the needle portion. According to this negative pressure, air is sucked into the air passage from the tip end surface of the needle portion, and this air is mixed with the fuel injected from the outer peripheral side surface of the needle portion.

【０００９】[0009]

【実施例】以下、本発明になる燃料噴射弁の一実施例を
図１から図４によって説明する。図１は燃料噴射弁を示
す縦断面図、図２は図１のＡ部の拡大部分断面図、図３
は図２におけるカバーの縦断面図、図４は図３の上部平
面図である。１は、上下方向が開口した略円筒状の本体
ハウジングであり、該本体ハウジングの上端の開口から
はソレノイド２と、コア３が挿入されコア３の上方鍔部
３Ａを介して本体ハウジング１の上端を内方へカシメる
ことによってソレノイド２及びコア３を本体ハウジング
１内に保持する。又、前記コア３の軸方向には燃料流路
３Ｂが貫通して穿設され、上方は開口して、例えば図示
せぬ燃料分配管に接続される。更に、本体ハウジング１
の上端には端子部材４が設けられており、この端子部材
４にはソレノイド２に結線された端子４Ａが設けられ
る。本体ハウジング１の下端からは、アーマチュアとし
ての弁保持体５がコア３の端部に対向して配置されると
ともに、弁保持体５に固着された弁体６が挿入され、弁
保持体５の上端とコア３との間にはスプリング７が縮設
される。又、弁体６と弁保持体５との連結部の外周に
は、弁保持体５の抜け止めと弁体６の軸方向移動量を規
制するための弁ストッププレート８が本体ハウジング１
に装着され、更に本体ハウジング１の下方より弁ストッ
ププレート８上に弁体ハウジング９が挿入され、本体ハ
ウジング１の下方端部を弁体ハウジング９の外周に向け
て内方へカシメることによって弁ストッププレート８及
び弁体ハウジング９を本体ハウジング１に固着できる。
弁体ハウジング９の先端（図１において下方端）には、
噴射孔９Ａが開口し、弁体ハウジング９内にある弁体６
を摺動自在に保持する弁室９Ｂと前記噴射孔９Ａとは円
錐形状の弁座９Ｃにて接続される。一方、弁体６の先端
部には、噴射孔９Ａ内に挿通されるとともに噴射孔９Ａ
の開口端（いいかえると弁体ハウジング９の先端面９
Ｄ）より突出するニードル部６Ａと、弁座９Ｃに着座す
る弁部６Ｂとが連続して形成される。以上は従来公知の
燃料噴射弁の構造であって、本発明になる燃料噴射弁は
前記目的達成の為に以下の構造を付加した。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the fuel injection valve according to the present invention will be described below with reference to FIGS. 1 is a vertical sectional view showing a fuel injection valve, FIG. 2 is an enlarged partial sectional view of a portion A of FIG. 1, and FIG.
2 is a vertical sectional view of the cover in FIG. 2, and FIG. 4 is a top plan view of FIG. Reference numeral 1 denotes a substantially cylindrical main body housing having an opening in the vertical direction. From the opening at the upper end of the main body housing, a solenoid 2 and a core 3 are inserted, and the upper end of the main body housing 1 is inserted through an upper flange portion 3A of the core 3. The solenoid 2 and the core 3 are held in the main body housing 1 by swaging inward. Further, a fuel passage 3B is bored in the axial direction of the core 3 and is opened at the upper side to be connected to, for example, a fuel distribution pipe (not shown). Further, the main body housing 1
A terminal member 4 is provided on the upper end of the, and a terminal 4A connected to the solenoid 2 is provided on the terminal member 4. From the lower end of the main body housing 1, a valve holding body 5 as an armature is arranged to face the end of the core 3, and a valve body 6 fixed to the valve holding body 5 is inserted so that the valve holding body 5 is A spring 7 is contracted between the upper end and the core 3. A valve stop plate 8 for preventing the valve holder 5 from coming off and restricting the axial movement amount of the valve element 6 is provided on the outer periphery of the connecting portion between the valve element 6 and the valve holder 5.
Mounted on the valve stop plate 8 from below the main body housing 1, and the lower end of the main body housing 1 is swaged inward toward the outer circumference of the valve body housing 9 to close the valve. The stop plate 8 and the valve body housing 9 can be fixed to the main body housing 1.
At the tip (lower end in FIG. 1) of the valve body housing 9,
The valve body 6 inside the valve body housing 9 with the injection hole 9A opened
The valve chamber 9B that slidably holds the injection hole 9A and the injection hole 9A are connected by a conical valve seat 9C. On the other hand, the tip of the valve body 6 is inserted into the injection hole 9A and the injection hole 9A
Open end (in other words, the tip surface 9 of the valve body housing 9
The needle portion 6A protruding from D) and the valve portion 6B seated on the valve seat 9C are continuously formed. The above is the structure of a conventionally known fuel injection valve, and the fuel injection valve according to the present invention has the following structure added to achieve the above object.

【００１０】本発明になる燃料噴射弁によると、弁体ハ
ウジングの先端面に、混合気形成孔と空気吸入路とを備
えたカバーを配置したものであり、図３，図４によって
カバーについて詳細に説明する。１０は筒状をなすカバ
ーであり、このカバー１０には弁体ハウジング９の外形
部に嵌合される内径部１０Ａと、弁体ハウジング９の先
端面９Ｄ（噴射孔９Ａはこの先端面９Ｄに開口する）に
対向する底部１０Ｂを有する。又、前記底部１０Ｂとカ
バー１０の先端面１０Ｃとの間に形成される厚肉部には
混合気形成孔１０Ｄと空気吸入路１０Ｅとが穿設され
る。この混合気形成孔１０Ｄはカバー１０の略中心部に
あってその一端がカバー１０の先端面１０Ｃに開口し、
他端は底部１０Ｂに開口する。一方、空気吸入路１０Ｅ
の一端は混合気形成孔１０Ｄに開口し、他端はカバー１
０の先端面１０Ｃ又はカバー１０の外周側面１０Ｆに開
口する。カバー１０の先端面１０Ｃに開口される空気吸
入路１０Ｅは図３において、カバー１０の軸方向左部分
に示され、カバー１０の外周側面１０Ｆに開口される空
気吸入路１０Ｅはカバー１０の軸方向右部分に示され
る。この空気吸入路１０Ｅの他端の開口部は適宜設定さ
れるもので且つその数、孔径、も実験等により決定され
る。一方、弁体６のニードル部６Ａに、一端がニードル
部の先端面に開口し、他端がニードル部の外周側面に開
口する空気通路を設けたものである。１１は、弁体６の
ニードル部６Ａに設けられる空気通路であり、この空気
通路１１は、空気吸入路１１Ａと、空気吸出路１１Ｂと
よりなる。空気吸入路１１Ａは、その一端がニードル部
６Ａの先端面６Ｃに開口し、ニードル部６Ａの軸方向上
側へ向けて穿設される。この先端面６Ｃは、ニードル部
６Ａの軸方向に対して略直交する側をいうもので外周を
除く。空気吸出路１１Ｂは、その一端が前記空気吸入路
１１Ａに開口し、他端がニードル部６Ａの外周側面６Ｄ
に開口する。而して、空気通路１１の一端は空気吸入路
１１Ａをしてニードル部６Ａの先端面６Ｃに開口し、他
端は空気吸出路１１Ｂをしてニードル部６Ａの外周側面
６Ｄに開口することになる。この弁体６のニードル部６
Ａに穿設された空気通路１１は図２によく示される。According to the fuel injection valve of the present invention, the cover provided with the air-fuel mixture forming hole and the air intake passage is arranged on the tip end surface of the valve body housing. Explained. Reference numeral 10 denotes a cylindrical cover. The cover 10 has an inner diameter portion 10A fitted to the outer shape of the valve body housing 9 and a tip surface 9D of the valve body housing 9 (the injection hole 9A is formed on the tip surface 9D). Has a bottom portion 10B facing (opening). A mixture forming hole 10D and an air suction passage 10E are formed in the thick portion formed between the bottom portion 10B and the tip surface 10C of the cover 10. The air-fuel mixture forming hole 10D is located substantially in the center of the cover 10, and one end of the air-fuel mixture forming hole 10D opens to the tip surface 10C of the cover 10,
The other end opens to the bottom portion 10B. On the other hand, the air intake passage 10E
Has one end open to the mixture forming hole 10D and the other end to the cover 1
0 at the front end surface 10C or the outer peripheral side surface 10F of the cover 10. The air suction passage 10E opened to the tip surface 10C of the cover 10 is shown in the axial left part of the cover 10 in FIG. 3, and the air suction passage 10E opened to the outer peripheral side surface 10F of the cover 10 is shown in the axial direction of the cover 10. Shown in the right part. The opening at the other end of the air suction passage 10E is appropriately set, and the number thereof and the hole diameter are also determined by experiments or the like. On the other hand, the needle portion 6A of the valve body 6 is provided with an air passage, one end of which opens at the tip end surface of the needle portion and the other end of which opens at the outer peripheral side surface of the needle portion. Reference numeral 11 denotes an air passage provided in the needle portion 6A of the valve body 6, and the air passage 11 includes an air suction passage 11A and an air suction passage 11B. One end of the air suction passage 11A opens at the tip surface 6C of the needle portion 6A, and is bored upward in the axial direction of the needle portion 6A. The tip surface 6C refers to a side that is substantially orthogonal to the axial direction of the needle portion 6A and excludes the outer circumference. One end of the air suction passage 11B is open to the air suction passage 11A and the other end is the outer peripheral side surface 6D of the needle portion 6A.
To open. Thus, one end of the air passage 11 serves as the air suction passage 11A and opens at the tip surface 6C of the needle portion 6A, and the other end serves as the air suction passage 11B and opens at the outer peripheral side surface 6D of the needle portion 6A. Become. Needle portion 6 of this valve body 6
The air passage 11 drilled in A is well shown in FIG.

【００１１】前記カバー１０は燃料噴射弁に対して以下
の如く組みつけられる。図２によって説明すると、弁体
ハウジング９の先端面９Ｄよりカバー１０の上端開口を
介して内径部１０Ａを弁体ハウジング９の外周へ嵌入
し、カバー１０の底部１０Ｂを弁体ハウジングの先端面
９Ｄに当接させ、かかる状態においてカバー１０の上部
鍔部１０Ｇを囲繞する本体ハウジング１の下端１Ａを内
方に向けてカシメ、もって本体ハウジング１に対して弁
体ハウジング９とカバー１０とを共に固着できた。かか
る状態にあって、混合気形成孔１０Ｄは、噴射孔９Ａに
対応して配置され、さらに弁体６のニードル部６Ａの先
端部は混合気形成孔１０Ｄ内に挿入して配置される。而
して、混合気形成孔１０Ｄ内には、混合気形成孔１０Ｄ
の内周とニードル部６Ａの外周側面６Ｄとによって環状
の間隙Ｓが形成される。さらに、ニードル部６Ａの外周
側面６Ｄに穿設される空気吸出路１１Ｂも混合気形成孔
１０Ｄ内に開口する。The cover 10 is assembled to the fuel injection valve as follows. Referring to FIG. 2, the inner diameter portion 10A is fitted into the outer periphery of the valve body housing 9 from the front end surface 9D of the valve body housing 9 through the upper end opening of the cover 10, and the bottom portion 10B of the cover 10 is fitted into the front end surface 9D of the valve body housing. And in this state, the lower end 1A of the main body housing 1 that surrounds the upper collar portion 10G of the cover 10 is inwardly swaged, so that the valve body housing 9 and the cover 10 are fixed to the main body housing 1 together. did it. In this state, the air-fuel mixture forming hole 10D is arranged corresponding to the injection hole 9A, and the tip portion of the needle portion 6A of the valve body 6 is inserted and arranged in the air-fuel mixture forming hole 10D. Thus, in the mixture forming hole 10D, the mixture forming hole 10D is formed.
An annular gap S is formed by the inner circumference of the needle and the outer peripheral side surface 6D of the needle portion 6A. Further, the air suction passage 11B formed in the outer peripheral side surface 6D of the needle portion 6A also opens into the mixture forming hole 10D.

【００１２】次にその作用について説明する。燃料噴射
弁において、ソレノイド２が消磁されている場合、弁体
６は弁保持体５を介してスプリング７のバネ力によって
弁座１３に向けて押圧されるので弁体６の弁部６Ｂが弁
座９Ｃに当接され、噴射孔９Ａより燃料が噴射されな
い。一方、ソレノイド２が励磁されると、弁保持体５は
スプリング７のバネ力に抗してコア３に吸着され、弁体
６の弁部６Ｂが弁座９Ｃより離反して弁ストッププレー
ト８に当接する迄軸方向に移動することにより弁部６Ｂ
と弁座９Ｃとの間に空隙が形成される。而して燃料流路
３Ｂより流入する燃料は弁室９Ｂを介して噴射孔９Ａよ
り外部に向けて噴射される。かかる燃料噴射弁からの燃
料噴射時において、以下について特に注目されなければ
ならない。すなわち、噴射孔９Ａより正圧力（通常は
２．５５kg／ｃｍ2 ）をもって噴射される燃料は噴射孔
９Ａの開口端を通過した後に混合気形成孔１０Ｄ内に噴
射されて流下するとともに混合気形成孔１０Ｄの開口端
より拡散された噴霧角をもって吸気管（図示せず）に噴
射される。ここで、噴射孔９Ａより噴射された燃料は、
混合気形成孔１０Ｄの内周とニードル部６Ａの外周側面
６Ｄとによって形成される環状の間隙Ｓ内を通過するこ
とになり、かかる間隙Ｓを通過する燃料速度の低下が完
全に抑止された。これは、ニードル部６Ａと混合気形成
孔１０Ｄとによって微少なる環状の間隙を形成できたこ
とによる。このように環状の間隙Ｓ内を速い流速をもっ
た燃料が噴射されて通過することによると、混合気形成
孔１０Ｄの内周面には大きな負圧が発生し、一方カバー
１０の先端面１０Ｃあるいはカバー１０の外周側面１０
Ｆにあっては吸気管内に臨んでいることよりそれらの部
位において大きな負圧が発生しない。以上によると、空
気吸入路１０Ｅの混合気形成孔１０Ｄへの開口と、カバ
ー１０の先端面１０Ｃあるいはカバー１０の外周側面１
０Ｆへの開口との間に大きな圧力差が生じるものであっ
て混合気形成孔１０Ｄに向けて空気流れが生じ、混合気
形成孔１０Ｄに開口する空気吸入路１０Ｅより混合気形
成孔１０Ｄ内の噴射燃料の外方部分に向けて空気が吸出
される。一方、環状の間隙Ｓ内を速い流速をもった燃料
が噴射されて通過することによると、ニードル部６Ａの
外周側面６Ｄには大きな負圧が発生し、一方、ニードル
部６Ａの先端面６Ｃにあっては吸気管内に臨んでいるこ
とより大きな負圧が発生することはない。以上によると
カバー１０の空気吸入路１０Ｅから混合気形成孔１０Ｄ
内に吸出された空気は、環状の間隙Ｓ内を通過する速い
流速をもった噴射燃料の外方部分に充分に混合され、一
方、ニードル部６Ａの外周側面６Ｄと先端面６Ｃとの間
に大きな圧力差が生じることからニードル部６Ａに設け
た空気通路１１としての空気吸入路１１Ａから空気吸出
路１１Ｂに向けて空気流れが生じ、空気吸出路１１Ｂよ
りニードル部６Ａの外周側面６Ｄを流れる噴射燃料の内
方部分に対して空気が吸出されて混合され、もって良好
に空気を噴射燃料中に混合できて燃料の微粒化を著しく
向上できたものである。要するに本発明の特徴は、噴射
孔から噴射される燃料の速度を低下させないことと、速
い流速を保有する燃料によって充分なる空気を、カバー
１０に設けた空気吸入路１０Ｅ及びニードル部６Ａに設
けた空気吸出路１１Ｂを介して燃料の内方部分及び外方
部分に吸出させるとともに混合させたことにある。更
に、混合気形成孔１０Ｄに空気吸入路１０Ｅを開口した
ことは、噴射孔９Ａより噴射された燃料が拡散する前
（拡散の直前）に燃料中に空気を混入できたもので、一
方ニードル部６Ａに空気通路１１を設けたことは、噴射
孔９Ａより噴射された燃料が大きく拡散する前（拡散の
直前）に燃料中に空気を混入できたものである。以上に
よると、以後の燃料の拡散時において、燃料の拡散エネ
ルギーを利用して空気を混合できたもので燃料の微粒化
を効果的に行なうことができたものである。又、従来の
燃料噴射弁にあっても弁体のニードル部を保護する為の
カバー及びニードル部を備えた弁体を有するもので、本
発明にあっては該カバー及び該弁体を利用したもので、
新たな部品を設ける必要がないので、部品点数の増加に
伴うコストの上昇は抑止できるとともに従来使用される
燃料噴射弁との互換性を有し、且つ機関への取りつけの
変更も必要としないもので、その実施は極めて容易なる
ものである。Next, the operation will be described. In the fuel injection valve, when the solenoid 2 is demagnetized, the valve body 6 is pressed toward the valve seat 13 by the spring force of the spring 7 via the valve holding body 5, so that the valve portion 6B of the valve body 6 is closed. The fuel is not injected from the injection hole 9A by being in contact with the seat 9C. On the other hand, when the solenoid 2 is excited, the valve holding body 5 is attracted to the core 3 against the spring force of the spring 7, and the valve portion 6B of the valve body 6 separates from the valve seat 9C to the valve stop plate 8. By moving axially until it abuts, the valve portion 6B
A gap is formed between the valve seat and the valve seat 9C. Thus, the fuel flowing in from the fuel flow path 3B is injected outward from the injection hole 9A through the valve chamber 9B. At the time of fuel injection from such a fuel injection valve, particular attention should be paid to the following. That is, the fuel injected with a positive pressure (usually 2.55 kg / cm @ 2) from the injection hole 9A passes through the open end of the injection hole 9A, and then is injected into the air-fuel mixture forming hole 10D to flow down and the air-fuel mixture forming hole. It is injected into an intake pipe (not shown) with a spray angle diffused from the open end of 10D. Here, the fuel injected from the injection hole 9A is
The fuel gas passes through the annular gap S formed by the inner periphery of the mixture forming hole 10D and the outer peripheral side face 6D of the needle portion 6A, and the decrease in the fuel velocity passing through the gap S is completely suppressed. This is because the needle portion 6A and the air-fuel mixture forming hole 10D can form a minute annular gap. When the fuel having a high flow velocity is injected and passes through the annular gap S in this manner, a large negative pressure is generated on the inner peripheral surface of the mixture forming hole 10D, while the tip surface 10C of the cover 10 is generated. Alternatively, the outer peripheral side surface 10 of the cover 10
In F, since it faces the inside of the intake pipe, a large negative pressure is not generated in those portions. According to the above, the opening of the air suction passage 10E to the air-fuel mixture forming hole 10D and the tip surface 10C of the cover 10 or the outer peripheral side surface 1 of the cover 10 are formed.
A large pressure difference is generated between the opening to 0F, an air flow is generated toward the air-fuel mixture forming hole 10D, and the inside of the air-fuel mixture forming hole 10D is opened from the air intake passage 10E opening to the air-fuel mixture forming hole 10D. Air is sucked toward the outer portion of the injected fuel. On the other hand, when the fuel having a high flow velocity is injected and passes through the annular gap S, a large negative pressure is generated on the outer peripheral side surface 6D of the needle portion 6A, while the distal end surface 6C of the needle portion 6A is generated. In that case, a negative pressure larger than that in the intake pipe is not generated. According to the above, the air-fuel mixture forming hole 10D is formed from the air intake passage 10E of the cover 10.
The air sucked in is sufficiently mixed with the outer portion of the injected fuel having a high flow velocity passing through the annular gap S, while the air is sucked between the outer peripheral side surface 6D and the tip surface 6C of the needle portion 6A. Since a large pressure difference is generated, an air flow is generated from the air suction passage 11A as the air passage 11 provided in the needle portion 6A toward the air suction passage 11B, and the jet that flows from the air suction passage 11B to the outer peripheral side surface 6D of the needle portion 6A. The air is sucked into and mixed with the inner portion of the fuel, so that the air can be mixed well with the injected fuel and the atomization of the fuel can be remarkably improved. In short, the features of the present invention are that the velocity of the fuel injected from the injection hole is not reduced, and that sufficient air is provided by the fuel having a high flow velocity in the air intake passage 10E and the needle portion 6A provided in the cover 10. This is because the fuel was sucked into and mixed with the inner and outer portions of the fuel through the air suction passage 11B. Further, the opening of the air intake passage 10E in the air-fuel mixture formation hole 10D means that air can be mixed into the fuel before the fuel injected from the injection hole 9A diffuses (immediately before the diffusion). The provision of the air passage 11 in 6A allows air to be mixed into the fuel before the fuel injected from the injection hole 9A largely diffuses (immediately before the diffusion). According to the above, during the subsequent diffusion of the fuel, the air can be mixed by utilizing the diffusion energy of the fuel, and the atomization of the fuel can be effectively performed. Further, even the conventional fuel injection valve has a valve body having a cover and a needle portion for protecting the needle portion of the valve body. In the present invention, the cover and the valve body are used. Things
Since it is not necessary to provide new parts, it is possible to suppress the cost increase due to the increase in the number of parts, it is compatible with the fuel injection valve used conventionally, and it is not necessary to change the mounting on the engine. Therefore, the implementation is extremely easy.

【００１３】又、カバー１０に穿設される空気吸入路１
０Ｅを複数設け、混合気形成孔１０Ｄに対して複数の空
気吸入路１０Ｅを開口させると、混合気形成孔１０Ｄ内
を流れる噴射燃料の全周囲に渡って均一に空気を混合で
きるもので燃料の微粒化が促進される。又、図５に示さ
れる如く、円形状をなす混合気形成孔１０Ｄの接線方向
に空気吸入路１０Ｅを開口すると、混合気形成孔１０Ｄ
内へ吸出される空気は混合気形成孔１０Ｄの円周方向に
沿って吸出されるもので、これによると混合気形成孔１
０Ｄ内を通過する燃料にスワールを起こすことができる
ものでより一層燃料と空気との混合を促進できるもので
あって更に燃料の微粒化を向上できる。この時空気吸入
路１０Ｅを複数設けることも一層好ましい。Further, the air suction passage 1 formed in the cover 10
By providing a plurality of 0E and opening a plurality of air intake passages 10E to the air-fuel mixture forming hole 10D, air can be mixed uniformly over the entire circumference of the injected fuel flowing in the air-fuel mixture forming hole 10D. Atomization is promoted. Further, as shown in FIG. 5, when the air suction passage 10E is opened in the tangential direction of the circular mixture forming hole 10D, the mixture forming hole 10D is formed.
The air sucked in is sucked along the circumferential direction of the air-fuel mixture forming hole 10D.
The swirl can be generated in the fuel passing through the inside of 0D, the mixing of the fuel and the air can be further promoted, and the atomization of the fuel can be further improved. At this time, it is more preferable to provide a plurality of air suction passages 10E.

【００１４】又、弁体６のニードル部６Ａに穿設される
空気通路は必ずしも空気吸入路と空気吸出路との二通路
を必要とするものでなく、図２の一点鎖線に示すごとく
ニードル部６Ａの先端面６Ｃより外周側面６Ｄに向って
斜め孔の一本孔とすることもできる。更には、ニードル
部６Ａに穿設される空気吸出路１１Ｂの開口をニードル
部６Ａの外周側面６Ｄにあって噴射孔９Ａの噴射側開口
端部（弁体ハウジングの先端面９Ｄ）、の近傍に開口し
たことによると、噴射孔９Ａより噴射される極めて高い
噴射燃料の流速をもって空気吸出路１１Ｂより燃料中に
空気を混合できたので燃料の霧化の向上を一層効果的に
行なうことができる。Further, the air passage bored in the needle portion 6A of the valve body 6 does not necessarily require two passages of the air suction passage and the air suction passage, and the needle portion is shown by the one-dot chain line in FIG. It is also possible to form one oblique hole from the front end surface 6C of 6A toward the outer peripheral side surface 6D. Further, the opening of the air suction passage 11B formed in the needle portion 6A is located near the injection side opening end of the injection hole 9A (the tip surface 9D of the valve body housing) on the outer peripheral side surface 6D of the needle portion 6A. Due to the opening, the air can be mixed into the fuel from the air suction passage 11B with an extremely high flow velocity of the injected fuel injected from the injection hole 9A, so that the atomization of the fuel can be more effectively improved.

【００１５】次に図６，図７，図８によって第二の実施
例を説明する。第一の実施例とはカバーのみが異なり他
は同一である。２０は筒状をなすカバーであり、このカ
バー２０には弁体ハウジング９の外形部に嵌合される内
径部２０Ａと、弁体ハウジング９の先端面９Ｄ（噴射孔
９Ａはこの先端面９Ｄに開口する）に対向する底部２０
Ｂを有する。又、前記底部２０Ｂとカバー２０の先端面
２０Ｃとの間に形成される厚肉部には混合気形成孔２０
Ｄと空気吸入路２０Ｅとが穿設される。この混合気形成
孔２０Ｄはカバー２０の略中心部にあってその一端がカ
バー２０の先端面２０Ｃに開口し、他端は底部２０Ｂに
開口する。一方、空気吸入路２０Ｅの一端はカバー２０
の底部２０Ｂに開口し、他端はカバー２０の先端面２０
Ｃ又はカバー２０の外周側面２０Ｆに開口する。カバー
２０の先端面２０Ｃに開口される空気吸入路２０Ｅは図
７において、カバー２０の軸方向左部分に示され、カバ
ー２０の外周側面２０Ｆに開口される空気吸入路２０Ｅ
はカバー２０の軸方向右部分に示される。一方、弁体６
のニードル部６Ａには、第一の実施例と同様なる空気通
路１１が穿設されるもので、空気吸入路１１Ａは一端が
ニードル部６Ａの先端面６Ｃに開口し、空気吸出路１１
Ｂは一端が空気吸入路１１Ａに開口し、他端がニードル
部６Ａの外周側面６Ｄに開口する。尚、本実施例にあっ
ては空気吸出路１１Ｂはニードル部６Ａの軸方向におけ
る横断面において複数穿設された。この空気吸出路１１
Ｂは図６に示される。Next, a second embodiment will be described with reference to FIGS. 6, 7 and 8. Only the cover is different from the first embodiment and the others are the same. Reference numeral 20 denotes a cylindrical cover. The cover 20 has an inner diameter portion 20A fitted to the outer shape of the valve body housing 9, and a tip surface 9D of the valve body housing 9 (the injection hole 9A is formed on the tip surface 9D). Bottom 20 facing (opening)
Have B. The mixture forming hole 20 is formed in the thick portion formed between the bottom portion 20B and the tip surface 20C of the cover 20.
D and the air suction passage 20E are drilled. The air-fuel mixture forming hole 20D is located substantially in the center of the cover 20, one end of which opens at the tip surface 20C of the cover 20, and the other end of which opens at the bottom 20B. On the other hand, one end of the air suction passage 20E has a cover 20 at one end.
Of the cover 20 is opened at the bottom 20B of the
C or the outer peripheral side surface 20F of the cover 20 is opened. The air intake passage 20E opened to the front end surface 20C of the cover 20 is shown in the axial left portion of the cover 20 in FIG. 7, and is opened to the outer peripheral side surface 20F of the cover 20.
Is shown in the axial right part of the cover 20. On the other hand, the valve body 6
An air passage 11 similar to that of the first embodiment is formed in the needle portion 6A of the air suction passage 11A. One end of the air suction passage 11A is opened to the tip surface 6C of the needle portion 6A, and the air suction passage 11 is opened.
B has one end opening to the air suction passage 11A and the other end opening to the outer peripheral side surface 6D of the needle portion 6A. In this embodiment, a plurality of air suction passages 11B are formed in the axial cross section of the needle portion 6A. This air suction passage 11
B is shown in FIG.

【００１６】前記カバー２０は燃料噴射弁に対して以下
の如く組みつけられる。図６によって説明すると、弁体
ハウジング９の先端面９Ｄよりカバー２０の上端開口を
介して内径部２０Ａを弁体ハウジング９の外周へ嵌入
し、カバー２０の底部２０Ｂを弁体ハウジング９の先端
面９Ｄに対して間隙Ｈをもって対向配置し、かかる状態
においてカバー２０の上部鍔部２０Ｇを囲繞する本体ハ
ウジング１の下端１Ａを内方に向けてカシメ、もって本
体ハウジング１に対して弁体ハウジング９とカバー２０
とを共に固着できた。そして弁体ハウジング９の先端面
９Ｄとカバー２０の底部２０Ｂとによって環状の空気室
Ｆが形成される。かかる状態にあって、混合気形成孔２
０Ｄは、噴射孔９Ａに対応して配置され、さらに弁体６
のニードル部６Ａの先端部は空気室Ｆ及び混合気形成孔
２０Ｄ内に挿入して配置される。而して、混合気形成孔
２０Ｄ内には、混合気形成孔２０Ｄの内周とニードル部
６Ａの外周とによって環状の間隙Ｓが形成される。尚、
前記間隙Ｈは例えば０．３mm程度のわずかな間隙であ
る。又、前記の如くカバー２０を弁体ハウジング９に組
みつけたことによると、空気吸入路２０Ｅの一端は空気
室Ｆに開口し、他端がカバー２０の先端面２０Ｃ又はカ
バー２０の外周側面２０Ｆに開口することになり、一方
ニードル部６Ａに設けた空気通路１１としての空気吸出
路１１Ｂは空気室Ｆ又は環状の間隙Ｓに開口する。The cover 20 is assembled to the fuel injection valve as follows. Explaining with reference to FIG. 6, the inner diameter portion 20A is fitted into the outer periphery of the valve body housing 9 from the front end surface 9D of the valve body housing 9 through the upper end opening of the cover 20, and the bottom portion 20B of the cover 20 is attached to the front end surface of the valve body housing 9. 9D is arranged opposite to each other with a gap H, and in this state, the lower end 1A of the main body housing 1 that surrounds the upper collar portion 20G of the cover 20 is inwardly swaged, so that the main body housing 1 and the valve body housing 9 are Cover 20
I was able to stick together and. An annular air chamber F is formed by the tip surface 9D of the valve body housing 9 and the bottom portion 20B of the cover 20. In this state, the mixture forming hole 2
0D is arranged corresponding to the injection hole 9A, and further the valve body 6
The tip portion of the needle portion 6A is inserted into the air chamber F and the air-fuel mixture forming hole 20D and arranged. Thus, in the air-fuel mixture forming hole 20D, an annular gap S is formed by the inner circumference of the air-fuel mixture forming hole 20D and the outer circumference of the needle portion 6A. still,
The gap H is a slight gap of about 0.3 mm, for example. Further, since the cover 20 is assembled to the valve body housing 9 as described above, one end of the air suction passage 20E is open to the air chamber F and the other end is the tip surface 20C of the cover 20 or the outer peripheral side surface 20F of the cover 20. On the other hand, the air suction passage 11B as the air passage 11 provided in the needle portion 6A is opened to the air chamber F or the annular gap S.

【００１７】次にその作用について説明する。燃料噴射
弁において、ソレノイド２が消磁されている場合、噴射
孔９Ａより燃料は噴射されるものでなく、ソレノイド２
が励磁されると、噴射孔９Ａより外部に向けて燃料が噴
射される。本実施例になる燃料噴射弁によると、噴射孔
９Ａより正圧力（通常は２．５５kg／ｃｍ2 ）をもって
噴射される燃料は噴射孔９Ａの開口端を通過した後に空
気室Ｆを通り、混合気形成孔２０Ｄ内に噴射されて流下
するとともに混合気形成孔２０Ｄの開口端より拡散され
た噴霧角をもって吸気管（図示せず）に噴射される。こ
こで、噴射孔９Ａより噴射された燃料は、空気室Ｆを通
過したのちに混合気形成孔２０Ｄの内周とニードル部６
Ａの外周とによって形成される環状の間隙Ｓ内を通過す
ることになり、かかる環状の間隙Ｓを通過する燃料速度
の低下が完全に抑止された。これは、空気室Ｆの間隙が
０．０３mm程度の極く微少なる間隙であって、且つ噴射
孔９Ａの開口に連なっていることと、ニードル部６Ａと
混合気形成孔２０Ｄとによって微少なる環状の間隙を形
成できたことによる。このように環状の間隙Ｓ内を速い
流速をもった燃料が噴射されて通過することによると、
空気室Ｆの混合気形成孔２０Ｄへの開口部には大きな負
圧が発生し、この負圧が空気室Ｆに作用して空気室Ｆ内
を負圧状態とし、一方カバー２０の先端面２０Ｃあるい
はカバー２０の外周側面２０Ｆにあっては吸気管内に臨
んでいることよりそれらの部位において大きな負圧が発
生しない。以上によると、空気室Ｆと、カバー２０の先
端面２０Ｃ、あるいはカバー２０の外周側面２０Ｆへの
開口との間に大きな圧力差が生じるものであって空気吸
入路２０Ｅ、空気室Ｆから混合気形成孔２０Ｄに向けて
空気流れが生じ、混合気形成孔２０Ｄの全周に渡って開
口する空気室Ｆより混合気形成孔２０Ｄ内に環状にして
均一なる空気が吸出される。そして混合気形成孔２０Ｄ
内に吸出された環状の空気は環状の間隙Ｓ内を通過する
速い流速をもった噴射燃料の外方部分に吸出されて混合
する。一方、環状の間隙Ｓ内を速い流速をもった燃料が
噴射されて通過することによると、ニードル部６Ａの外
周側面６Ｄには大きな負圧が発生し、他方、ニードル部
６Ａの先端面６Ｃにあっては吸気管内に臨んでいること
より大きな負圧が発生することはない。以上によるとカ
バー２０の空気吸入路２０Ｅから混合気形成孔２０Ｄ内
に吸出された空気は、環状の間隙Ｓ内を通過する速い流
速をもった噴射燃料の外方部分に充分に混合され、一
方、ニードル部６Ａの外周側面６Ｄとニードル部６Ａの
先端面６Ｃとの間に大きな圧力差が生じることからニー
ドル部６Ａに設けた空気通路１１としての空気吸入路１
１Ａから空気吸出路１１Ｂに向けて空気流れが生じ、空
気吸出路１１Ｂよりニードル部６Ａの外周側面６Ｄを流
れる噴射燃料の内方部分に対して空気が吸出されて混合
され、もって良好に空気を噴射燃料中に混合できて燃料
の微粒化を著しく向上できたものである。更に、空気室
Ｆは噴射孔９Ａの開口端に直接的に形成され、空気室Ｆ
より混合気形成孔２０Ｄが連設され、一方ニードル部６
Ａの空気吸出路１１Ｂは空気室Ｆ又は環状の間隙Ｓ内に
開口するので噴射孔９Ａより噴射された燃料が拡散する
前（拡散する直前）の燃料の外方部分及び内方部分に空
気を混入できたもので、以後の燃料の拡散時において、
燃料の拡散エネルギーを利用して空気を混合できたもの
で燃料の微粒化を効果的に行なうことができたものであ
る。Next, the operation will be described. In the fuel injection valve, when the solenoid 2 is demagnetized, the fuel is not injected from the injection hole 9A but the solenoid 2
Is excited, fuel is injected from the injection hole 9A toward the outside. According to the fuel injection valve of this embodiment, the fuel injected with the positive pressure (usually 2.55 kg / cm @ 2) from the injection hole 9A passes through the open end of the injection hole 9A and then passes through the air chamber F to form the air-fuel mixture. It is injected into the forming hole 20D and flows down, and is injected into an intake pipe (not shown) with a spray angle diffused from the opening end of the mixture forming hole 20D. Here, the fuel injected from the injection hole 9A passes through the air chamber F and then the inner periphery of the mixture forming hole 20D and the needle portion 6
The fuel cell passes through the annular gap S formed by the outer periphery of A and the decrease in the fuel velocity passing through the annular gap S is completely suppressed. This is a very small gap of about 0.03 mm in the air chamber F, and is connected to the opening of the injection hole 9A, and the needle portion 6A and the mixture forming hole 20D form a small annular shape. The reason is that the gap can be formed. According to the fact that the fuel having a high flow velocity is injected and passes through the annular gap S as described above,
A large negative pressure is generated in the opening of the air chamber F to the air-fuel mixture forming hole 20D, and this negative pressure acts on the air chamber F to bring the inside of the air chamber F into a negative pressure state, while the front end surface 20C of the cover 20. Alternatively, since the outer peripheral side surface 20F of the cover 20 faces the inside of the intake pipe, a large negative pressure is not generated in those portions. According to the above, a large pressure difference is generated between the air chamber F and the front end surface 20C of the cover 20 or the opening to the outer peripheral side surface 20F of the cover 20, and the air intake passage 20E and the air chamber F are mixed. An air flow is generated toward the formation hole 20D, and uniform air is sucked into the mixture formation hole 20D in an annular shape from the air chamber F that is opened over the entire circumference of the mixture formation hole 20D. And the mixture forming hole 20D
The annular air sucked inside is sucked into and mixed with the outer portion of the injected fuel having a high flow velocity passing through the annular gap S. On the other hand, when the fuel having a high flow velocity is injected and passes through the annular gap S, a large negative pressure is generated on the outer peripheral side surface 6D of the needle portion 6A, and on the other hand, on the tip surface 6C of the needle portion 6A. In that case, a negative pressure larger than that in the intake pipe is not generated. According to the above, the air sucked into the air-fuel mixture forming hole 20D from the air suction passage 20E of the cover 20 is sufficiently mixed with the outer portion of the injected fuel having a high flow velocity passing through the annular gap S, while Since there is a large pressure difference between the outer peripheral side surface 6D of the needle portion 6A and the tip surface 6C of the needle portion 6A, the air suction passage 1 as the air passage 11 provided in the needle portion 6A.
An air flow is generated from 1A toward the air suction passage 11B, and the air is sucked and mixed from the air suction passage 11B to the inner portion of the injected fuel flowing through the outer peripheral side surface 6D of the needle portion 6A, so that the air is favorably discharged. It can be mixed in the injected fuel and the atomization of the fuel can be remarkably improved. Further, the air chamber F is formed directly at the opening end of the injection hole 9A, and
Further, the air-fuel mixture forming hole 20D is continuously provided, and the needle portion 6 is provided.
Since the air suction passage 11B of A opens in the air chamber F or the annular gap S, air is injected into the outer and inner portions of the fuel before the fuel injected from the injection hole 9A diffuses (immediately before the diffusion). It was able to be mixed in, and during the subsequent diffusion of fuel,
It was possible to mix the air by utilizing the diffusion energy of the fuel and to effectively atomize the fuel.

【００１８】次に図９，図１０，図１１によって第三の
実施例を説明する。第一の実施例とはカバーが異なり他
は同一である。３０は筒状をなすカバーであり、このカ
バー３０には弁体ハウジング９の外形部に嵌合される内
径部３０Ａと、弁体ハウジング９の先端面９Ｄ（噴射孔
９Ａはこの先端面９Ｄに開口する）に対向する底部３０
Ｂを有する。又、前記底部３０Ｂとカバー３０の先端面
３０Ｃとの間に形成される厚肉部には混合気形成孔３０
Ｄと空気吸出溝３０Ｈと空気吸入路３０Ｅとが穿設され
る。この混合気形成孔３０Ｄはカバー３０の略中心部に
あってその一端がカバー３０の先端面３０Ｃに開口し、
他端は底部３０Ｂに開口する。一方、空気吸出溝３０Ｈ
は底部３０Ｂに凹設されるものでその一端は混合気形成
孔３０Ｄに開口する。又空気吸入路３０Ｅはその一端が
空気吸出溝３０Ｈに開口し、他端はカバー３０の先端面
３０Ｃ又はカバー３０の外周側面３０Ｆに開口する。カ
バー３０の先端面３０Ｃに開口される空気吸入路３０Ｅ
は図１０において、カバー３０の軸方向左部分に示さ
れ、カバー３０の外周側面３０Ｆに開口される空気吸入
路３０Ｅはカバー３０の軸方向右部分に示される。この
空気吸入路３０Ｅの他端の開口部は適宜設定されるもの
で且つその数、孔径、も実験等により決定される。一
方、弁体６のニードル部６Ａには第一の実施例と同様な
る空気通路１１が穿設されるもので、空気吸出路１１Ａ
は一端がニードル部６Ａの先端面６Ｃに開口し、空気吸
出路１１Ｂは一端が空気吸入路１１Ａに開口し、他端が
ニードル部６Ａの外周側面６Ｄに開口する。尚、本実施
例にあっては空気吸出路１１Ｂはニードル部６Ａの軸方
向において多段に設けられた。Next, a third embodiment will be described with reference to FIGS. 9, 10 and 11. The cover is different from that of the first embodiment, and the other parts are the same. Reference numeral 30 denotes a cylindrical cover. The cover 30 has an inner diameter portion 30A fitted to the outer shape of the valve body housing 9 and a tip surface 9D of the valve body housing 9 (the injection hole 9A is formed on the tip surface 9D). Bottom 30 facing (opening)
Have B. In addition, the mixture forming hole 30 is formed in the thick portion formed between the bottom portion 30B and the tip surface 30C of the cover 30.
D, the air suction groove 30H, and the air suction passage 30E are bored. The air-fuel mixture forming hole 30D is located substantially in the center of the cover 30, and one end of the air-fuel mixture forming hole 30D is opened to the tip surface 30C of the cover 30,
The other end opens to the bottom portion 30B. On the other hand, air suction groove 30H
Is recessed in the bottom portion 30B, and one end thereof opens into the mixture forming hole 30D. Further, one end of the air suction passage 30E is opened to the air suction groove 30H, and the other end is opened to the tip surface 30C of the cover 30 or the outer peripheral side surface 30F of the cover 30. Air suction passage 30E opened at the front end surface 30C of the cover 30
10, is shown in the axial left part of the cover 30, and the air suction passage 30E opened to the outer peripheral side surface 30F of the cover 30 is shown in the axial right part of the cover 30. The opening at the other end of the air suction passage 30E is appropriately set, and the number thereof and the hole diameter are also determined by experiments or the like. On the other hand, the needle portion 6A of the valve body 6 is provided with an air passage 11 similar to that of the first embodiment.
Has one end opening to the tip surface 6C of the needle portion 6A, one end of the air suction passage 11B opening to the air suction passage 11A, and the other end opening to the outer peripheral side surface 6D of the needle portion 6A. In this embodiment, the air suction passages 11B are provided in multiple stages in the axial direction of the needle portion 6A.

【００１９】前記カバー３０は燃料噴射弁に対して以下
の如く組みつけられる。図９によって説明すると、弁体
ハウジング９の先端面９Ｄよりカバー３０の上端開口を
介して内径部３０Ａを弁体ハウジング９の外周へ嵌入
し、カバー３０の底部３０Ｂを弁体ハウジング９の先端
面９Ｄに当接させ、かかる状態においてカバー３０の上
部鍔部３０Ｇを囲繞する本体ハウジング１の下端１Ａを
内方に向けてカシメ、もって本体ハウジング１に対して
弁体ハウジング９とカバー３０とを共に固着できた。か
かる状態にあって、混合気形成孔３０Ｄは、噴射孔９Ａ
に対応して配置され、さらに弁体６のニードル部６Ａの
先端部は混合気形成孔３０Ｄ内に挿入して配置される。
而して、混合気形成孔３０Ｄ内には、混合気形成孔３０
Ｄの内周とニードル部６Ａの外周とによって環状の間隙
Ｓが形成される。一方、空気吸出溝３０Ｈの上方開口は
弁体ハウジング９の先端面９Ｄによって閉塞されて通路
をなし、この通路の一端は混合気形成孔３０Ｄに開口
し、他端はカバー３０の先端面３０Ｃ又は外周側面３０
Ｆに開口する。又、ニードル部６Ａの外周側面６Ｄに穿
設される空気吸出路１１Ｂは環状の間隙Ｓに開口され
る。The cover 30 is assembled to the fuel injection valve as follows. Explaining with reference to FIG. 9, the inner diameter portion 30A is fitted into the outer periphery of the valve body housing 9 from the front end surface 9D of the valve body housing 9 through the upper end opening of the cover 30, and the bottom portion 30B of the cover 30 is attached to the front end surface of the valve body housing 9. 9D, and in such a state, the lower end 1A of the main body housing 1 surrounding the upper collar portion 30G of the cover 30 is swaged inward, so that the valve body housing 9 and the cover 30 are both attached to the main body housing 1. I could stick. In such a state, the air-fuel mixture forming hole 30D is connected to the injection hole 9A.
And the tip of the needle portion 6A of the valve body 6 is inserted into the mixture forming hole 30D.
Thus, the mixture forming hole 30D is provided in the mixture forming hole 30D.
An annular gap S is formed by the inner circumference of D and the outer circumference of the needle portion 6A. On the other hand, the upper opening of the air suction groove 30H is closed by the front end surface 9D of the valve body housing 9 to form a passage, one end of this passage is opened to the air-fuel mixture forming hole 30D, and the other end is opened to the front end surface 30C of the cover 30. Perimeter side 30
Open to F. Further, the air suction passage 11B formed in the outer peripheral side surface 6D of the needle portion 6A is opened in the annular gap S.

【００２０】その作用について説明すると、噴射孔９Ａ
より噴射される燃料は噴射孔９Ａの開口端を通過した後
に混合気形成孔３０Ｄ内に噴射されて流下するとともに
混合気形成孔３０Ｄの開口端より拡散された噴霧角をも
って吸気管（図示せず）に噴射される。ここで、噴射孔
９Ａより噴射された燃料は、混合気形成孔３０Ｄの内周
とニードル部６Ａの外周とによって形成される環状の間
隙Ｓ内を通過することになり、かかる間隙Ｓを通過する
燃料速度の低下が完全に抑止された。これは、ニードル
部６Ａと混合気形成孔３０Ｄとによって微少なる環状の
間隙を形成できたことによる。このように環状の間隙Ｓ
内を速い流速をもった燃料が噴射されて通過することに
よると、混合気形成孔３０Ｄの内周面には大きな負圧が
発生し、一方カバー３０の先端面３０Ｃあるいはカバー
３０の外周側面３０Ｆにあっては吸気管内に臨んでいる
ことよりそれらの部位において大きな負圧が発生しな
い。以上によると、空気吸出溝３０Ｈの混合気形成孔３
０Ｄへの開口と、空気吸入路３０Ｅのカバー３０の先端
面３０Ｃあるいはカバー３０の外周側面３０Ｆへの開口
との間に大きな圧力差が生じるものであって混合気形成
孔３０Ｄに向けて空気流れが生じ、混合気形成孔３０Ｄ
に開口する空気吸出溝３０Ｈより混合気形成孔３０Ｄ内
に空気が吸出される。そして混合気形成孔３０Ｄ内に吸
出された空気は環状の間隙Ｓ内を通過する速い流速をも
った噴射燃料の外方部分に充分に混合される。一方、環
状の間隙Ｓ内を速い流速をもった燃料が噴射されて通過
することによると、ニードル部６Ａの外周側面６Ｄには
大きな負圧が発生し、他方、ニードル部６Ａの先端面６
Ｃにあっては吸気管内に臨んでいることより大きな負圧
が発生することはない。以上によると、ニードル部６Ａ
の外周側面６Ｄとニードル部６Ａの先端面６Ｃとの間に
大きな圧力差が生じることからニードル部６Ａに設けた
空気通路１１としての空気吸入路１１Ａから空気吸出路
１１Ｂに向けて空気流れが生じ、空気吸出路１１Ｂより
ニードル部６Ａの外周側面６Ｄを流れる噴射燃料の内方
部分に対して空気が吸出されて混合され、もって良好に
空気を噴射燃料中に混合できて燃料の微粒化を著しく向
上できたものである。特に、カバー３０の底部３０Ｂに
空気吸出溝３０Ｈを凹設し、弁体ハウジング９の先端面
９Ｄにカバー３０の底部３０Ｄを当接させたことによる
と、空気吸出溝３０Ｈは噴射孔９Ａが開口する混合気形
成孔３０Ｄに直接的に開口できるとともにニードル部６
Ａの外周側面６Ｄに開口する空気吸出路１１Ｂも混合気
形成孔３０Ｄの環状の間隙Ｓ内に開口させることができ
たので、噴射孔９Ａより噴射された燃料が拡散する前
（拡散の直前）に、燃料中の内方及び外方に渡って空気
を混入できたもので、以後の燃料の拡散時において、燃
料の拡散エネルギーを利用して空気を混合できたもので
燃料の微粒化を効果的に行なうことができたものであ
る。The operation will be described. The injection hole 9A
The fuel thus injected passes through the opening end of the injection hole 9A, is injected into the air-fuel mixture forming hole 30D and flows down, and has an injection angle (not shown) with a spray angle diffused from the opening end of the air-fuel mixture forming hole 30D. ) Is injected. Here, the fuel injected from the injection hole 9A passes through the annular gap S formed by the inner periphery of the mixture forming hole 30D and the outer periphery of the needle portion 6A, and passes through the gap S. The reduction in fuel speed was completely suppressed. This is because the needle portion 6A and the air-fuel mixture forming hole 30D were able to form a minute annular gap. Thus, the annular gap S
When the fuel having a high flow velocity is injected and passes through the inside, a large negative pressure is generated on the inner peripheral surface of the air-fuel mixture forming hole 30D, while the front end surface 30C of the cover 30 or the outer peripheral side surface 30F of the cover 30 is generated. In that case, a large negative pressure is not generated in those portions because it faces the inside of the intake pipe. According to the above, the mixture forming hole 3 of the air suction groove 30H
A large pressure difference is generated between the opening to 0D and the opening to the tip surface 30C of the cover 30 of the air suction passage 30E or the outer peripheral side surface 30F of the cover 30, and the air flow toward the air-fuel mixture forming hole 30D. Occurs and the mixture forming hole 30D
Air is sucked into the air-fuel mixture forming hole 30D from the air suction groove 30H opening at. Then, the air sucked into the air-fuel mixture forming hole 30D is sufficiently mixed with the outer portion of the injected fuel having a high flow velocity passing through the annular gap S. On the other hand, when the fuel having a high flow velocity is injected and passes through the annular gap S, a large negative pressure is generated on the outer peripheral side surface 6D of the needle portion 6A, while the distal end surface 6 of the needle portion 6A is generated.
In C, a negative pressure larger than that in the intake pipe is not generated. According to the above, the needle portion 6A
Since a large pressure difference is generated between the outer peripheral side surface 6D of the needle 6A and the tip surface 6C of the needle portion 6A, an air flow is generated from the air suction passage 11A as the air passage 11 provided in the needle portion 6A toward the air suction passage 11B. , The air is sucked and mixed from the air suction passage 11B to the inner portion of the injected fuel flowing on the outer peripheral side surface 6D of the needle portion 6A, so that the air can be mixed well in the injected fuel and the atomization of the fuel is remarkably reduced. It has been improved. Particularly, since the air suction groove 30H is provided in the bottom portion 30B of the cover 30 and the bottom portion 30D of the cover 30 is brought into contact with the tip end surface 9D of the valve body housing 9, the air suction groove 30H has the injection hole 9A opened. And the needle portion 6 can be directly opened in the mixture forming hole 30D.
Since the air suction passage 11B opening on the outer peripheral side surface 6D of A can also be opened within the annular gap S of the air-fuel mixture forming hole 30D, before the fuel injected from the injection hole 9A diffuses (immediately before diffusion). In addition, it was possible to mix air inside and outside the fuel, and at the time of the subsequent diffusion of the fuel, it was possible to mix the air by using the diffusion energy of the fuel, which is effective in atomizing the fuel. It was possible to do it.

【００２１】又、空気吸出溝３０Ｈを複数設け、混合気
形成孔３０Ｄに対して複数の空気吸出溝３０Ｈを開口さ
せると、混合気形成孔３０Ｄ内を流れる噴射燃料の全周
囲に渡って均一に空気を混合できるもので燃料の微粒化
が促進される。Further, when a plurality of air suction grooves 30H are provided and the plurality of air suction grooves 30H are opened with respect to the air-fuel mixture forming holes 30D, the injected fuel flowing in the air-fuel mixture forming holes 30D is evenly distributed around the entire circumference. It can mix air and promotes atomization of fuel.

【００２２】又、図１２，図１３に示される如く、円形
状をなす混合気形成孔３０Ｄの接線方向に空気吸出溝３
０Ｈを開口すると、混合気形成孔３０Ｄ内へ吸出される
空気は混合気形成孔３０Ｄの円周方向に沿って吸出され
るもので、これによると混合気形成孔３０Ｄ内を通過す
る燃料にスワールを起こすことができるもので、より一
層燃料と空気との混合を促進できるものであって更に燃
料の微粒化を向上できる。この時空気吸出溝３０Ｈを複
数設けることは一層好ましい。Further, as shown in FIGS. 12 and 13, the air suction groove 3 is formed in the tangential direction of the circular mixture forming hole 30D.
When 0H is opened, the air sucked into the air-fuel mixture forming hole 30D is sucked along the circumferential direction of the air-fuel mixture forming hole 30D, and according to this, the swirl is applied to the fuel passing through the air-fuel mixture forming hole 30D. Which can further promote the mixing of fuel and air, and further improve atomization of fuel. At this time, it is more preferable to provide a plurality of air suction grooves 30H.

【００２３】次に図１４，図１５，図１６によって第四
の実施例を説明する。第一の実施例とはカバーが異な
る。４０は筒状をなすカバーであり、このカバー４０に
は弁体ハウジング９の外形部に嵌合される内径部４０Ａ
と、弁体ハウジング９の先端面９Ｄ（噴射孔９Ａはこの
先端面９Ｄに開口する）に対向する底部４０Ｂを有す
る。底部４０Ｂの中心より上方に向けて円柱部４０Ｐが
突起して形成されるもので、円柱部４０Ｐの上端面４０
Ｒとカバー４０の先端面４０Ｃとの間に混合気形成孔４
０Ｄが穿設される。すなわち、混合気形成孔４０Ｄの一
端はカバー４０の先端面４０Ｃに開口し、他端は円柱部
４０Ｐの上端面４０Ｒに開口する。円柱部４０Ｐの上端
面４０Ｒには空気吸出路４０Ｈが凹設されるもので、空
気吸出路４０Ｈの一端は円柱部４０Ｐの外形部４０Ｔに
開口し、他端は混合気形成孔４０Ｄに開口する。円柱部
４０Ｐの外側方にある底部４０Ｂには空気吸入路４０Ｅ
が開口し、他端はカバー４０の先端面４０Ｃ又は外側周
面４０Ｆに開口する。カバー４０の先端面４０Ｃに開口
される空気吸入路４０Ｅは図１５においてカバー４０の
軸方向左部分に示され、カバー４０の外周側面４０Ｆに
開口される空気吸入路４０Ｅはカバー４０の軸方向右部
分に示される。この空気吸入路４０Ｅの他端の開口部は
適宜設定されるもので且つその数、孔径、も実験等によ
り決定される。一方、弁体６のニードル部６Ａには第一
の実施例と同様なる空気通路１１が穿設されるもので、
空気吸入路１１Ａは一端がニードル部６Ａの先端面６Ｃ
に開口し、空気吸出路１１Ｂは一端が空気吸入路１１Ａ
に開口し、他端がニードル部６Ａの外周側面６Ｄに開口
する。尚、本実施例にあっては空気吸出路１１Ｂはニー
ドル部６Ａの軸方向にあって多段に穿設されるとともに
軸方向に直交する横断面において複数穿設された。Next, a fourth embodiment will be described with reference to FIGS. 14, 15 and 16. The cover is different from that of the first embodiment. Reference numeral 40 denotes a cylindrical cover, and this cover 40 has an inner diameter portion 40A fitted to the outer shape portion of the valve body housing 9.
And a bottom portion 40B facing the front end surface 9D of the valve body housing 9 (the injection hole 9A opens to the front end surface 9D). The columnar portion 40P is formed so as to project upward from the center of the bottom portion 40B, and the upper end surface 40 of the columnar portion 40P is formed.
The air-fuel mixture forming hole 4 is formed between the R and the tip surface 40C of the cover 40.
0D is drilled. That is, one end of the air-fuel mixture forming hole 40D is opened to the tip surface 40C of the cover 40, and the other end is opened to the upper end surface 40R of the columnar portion 40P. An air suction passage 40H is recessed in the upper end surface 40R of the columnar portion 40P. One end of the air suction passage 40H is opened to the outer shape portion 40T of the columnar portion 40P, and the other end is opened to the mixture forming hole 40D. . An air intake passage 40E is provided in a bottom portion 40B outside the column portion 40P.
Is opened, and the other end is opened to the tip surface 40C or the outer peripheral surface 40F of the cover 40. The air intake passage 40E opened to the front end surface 40C of the cover 40 is shown in the axial left portion of the cover 40 in FIG. 15, and the air intake passage 40E opened to the outer peripheral side surface 40F of the cover 40 is the axial right portion of the cover 40. Shown in part. The opening at the other end of the air suction passage 40E is appropriately set, and the number thereof and the hole diameter are also determined by experiments or the like. On the other hand, the needle portion 6A of the valve body 6 is provided with an air passage 11 similar to that of the first embodiment.
One end of the air suction passage 11A has a tip surface 6C of the needle portion 6A.
And the air suction passage 11B has one end having an air suction passage 11A.
And the other end opens to the outer peripheral side surface 6D of the needle portion 6A. In this embodiment, the air suction passages 11B are formed in multiple stages in the axial direction of the needle portion 6A, and a plurality of air suction passages 11B are formed in a cross section orthogonal to the axial direction.

【００２４】前記カバーは燃料噴射弁に対して以下の如
く組みつけられる。図１４によって説明すると、弁体ハ
ウジング９の先端面９Ｄよりカバー４０の上端開口を介
して内径部４０Ａを弁体ハウジング９の外周へ嵌入し、
カバー４０の円柱部４０Ｐの上端面４０Ｒを弁体ハウジ
ング９の先端面９Ｄに当接させ、かかる状態においてカ
バー４０の上部鍔部４０Ｇを囲繞する本体ハウジング１
の下端１Ａを内方に向けてカシメ、もって本体ハウジン
グ１に対して弁体ハウジング９とカバー４０とを共に固
着できた。かかる状態にあって、混合気形成孔４０Ｄ
は、噴射孔９Ａに連設して配置され、さらに弁体６のニ
ードル部６Ａの先端部は混合気形成孔４０Ｄ内に挿入し
て配置される。又、弁体ハウジング９の先端面９Ｄとカ
バー４０の底部４０Ｂとによって空気室Ｆが形成され
る。而して、混合気形成孔４０Ｄ内には、混合気形成孔
４０Ｄの内周とニードル部６Ａの外周とによって環状の
間隙Ｓが形成される。一方、円柱部４０Ｐの上端面４０
Ｒに凹設された空気吸出路４０Ｈの上方開口は弁体ハウ
ジング９の先端面９Ｄによって閉塞されて通路をなし、
この空気吸出路４０Ｈの一端は混合気形成孔４０Ｄに開
口し、他端は円柱部４０Ｐの外形部４０Ｔに開口して空
気室Ｆに連絡され、更に空気室Ｆには空気吸入路４０Ｅ
が開口する。一方、弁体６のニードル部６Ａの外周側面
６Ｄに穿設された空気吸出路１１Ｂは環状の間隙Ｓに開
口する。The cover is assembled to the fuel injection valve as follows. Explaining with reference to FIG. 14, the inner diameter portion 40A is fitted into the outer periphery of the valve body housing 9 from the tip end surface 9D of the valve body housing 9 through the upper end opening of the cover 40,
The main body housing 1 in which the upper end surface 40R of the columnar portion 40P of the cover 40 is brought into contact with the front end surface 9D of the valve body housing 9 and surrounds the upper collar portion 40G of the cover 40 in this state.
The lower end 1A was inwardly swaged so that the valve body housing 9 and the cover 40 could be fixed to the main body housing 1 together. In such a state, the mixture forming hole 40D
Is arranged so as to be continuous with the injection hole 9A, and the tip end of the needle portion 6A of the valve body 6 is inserted and arranged in the mixture forming hole 40D. An air chamber F is formed by the tip surface 9D of the valve body housing 9 and the bottom portion 40B of the cover 40. Thus, an annular gap S is formed in the air-fuel mixture forming hole 40D by the inner circumference of the air-fuel mixture forming hole 40D and the outer circumference of the needle portion 6A. On the other hand, the upper end surface 40 of the cylindrical portion 40P
The upper opening of the air suction passage 40H recessed in R is closed by the tip surface 9D of the valve body housing 9 to form a passage,
One end of the air suction passage 40H is opened to the air-fuel mixture forming hole 40D, and the other end is opened to the outer shape portion 40T of the columnar portion 40P to communicate with the air chamber F. Further, the air suction passage 40E is provided in the air chamber F.
Opens. On the other hand, the air suction passage 11B formed in the outer peripheral side surface 6D of the needle portion 6A of the valve body 6 opens into the annular gap S.

【００２５】その作用について説明すると、噴射孔９Ａ
より噴射される燃料は噴射孔９Ａの開口端を通過した後
に混合気形成孔４０Ｄ内に噴射されて流下するとともに
混合気形成孔４０Ｄの開口端より拡散された噴霧角をも
って吸気管（図示せず）に噴射される。ここで、噴射孔
９Ａより噴射された燃料は、混合気形成孔４０Ｄの内周
とニードル部６Ａの外周とによって形成される環状の間
隙Ｓ内を通過することになり、かかる間隙Ｓを通過する
燃料速度の低下が完全に抑止された。このように環状の
間隙Ｓ内を速い流速をもった燃料が噴射されて通過する
ことによると、混合気形成孔４０Ｄの内周面には大きな
負圧が発生し、一方カバー４０の先端面４０Ｃあるいは
カバー４０の外周側面４０Ｆにあっては吸気管内に臨ん
でいることよりそれらの部位において大きな負圧が発生
しないもので空気吸入路４０Ｅを介してカバー４０の先
端面４０Ｃあるいは外周側面４０Ｆに連絡される空気室
Ｆ内の負圧をあげるものでない。以上によると、空気吸
出路４０Ｈの混合気形成孔４０Ｄへの開口と、空気室Ｆ
との間に大きな圧力差が生じるものであって混合気形成
孔４０Ｄに開口する空気吸出路４０Ｈより混合気形成孔
４０Ｄ内に空気が吸出される。そして混合気形成孔４０
Ｄ内に吸出された空気は環状の間隙Ｓ内を通過する速い
流速をもった燃料の外方部分に充分に混合される。一
方、環状の間隙Ｓ内を速い流速をもった燃料が噴射され
て通過することによると、ニードル部６Ａの外周側面６
Ｄには大きな負圧が発生し、一方、ニードル部６Ａの先
端面６Ｃにあっては吸気管内に臨んでいることより大き
な負圧が発生することはない。而して、ニードル部６Ａ
の外周側面６Ｄと先端面６Ｃとの間に大きな圧力差が生
じることからニードル部６Ａに設けた空気通路１１とし
ての空気吸入路１１Ａから空気吸出路１１Ｂに向けて空
気流れが生じ、空気吸出路１１Ｂよりニードル部６Ａの
外周側面６Ｄを流れる噴射燃料の内方部分に対して空気
が吸出されて混合され、もって良好に空気を噴射燃料中
に混合できて燃料の微粒化を著しく向上できたものであ
る。特に、カバー４０の底部４０Ｂより円柱部４０Ｐを
上方に向けて突出し、この円柱部４０Ｐの上端面４０Ｒ
に空気吸出路４０Ｈを凹設し、弁体ハウジング９の先端
面９Ｄにカバー４０の円柱部４０Ｐの上端面４０Ｒを当
接させたことによると、空気吸出路４０Ｈは噴射孔９Ａ
が開口する混合気形成孔に直接的に開口でき、しかもニ
ードル部６Ａに設けた空気吸出路１１Ｂを環状の間隙Ｓ
に開口できたもので、噴射孔９Ａより噴射される極めて
速い速度を有する噴射燃料によって空気が吸出され、さ
らには噴射孔９Ａより噴射された燃料が拡散する前（拡
散の直前）に、燃料中に空気を混入できたもので、以後
の燃料の拡散時において、燃料の拡散エネルギーを利用
して空気を混合できたもので燃料の微粒化を効果的に行
なうことができたものである。The operation will be described. The injection hole 9A
The fuel thus injected passes through the open end of the injection hole 9A, is injected into the air-fuel mixture forming hole 40D and flows down, and has an atomization angle (not shown) diffused from the open end of the air-fuel mixture forming hole 40D. ) Is injected. Here, the fuel injected from the injection hole 9A passes through the annular gap S formed by the inner periphery of the mixture forming hole 40D and the outer periphery of the needle portion 6A, and passes through the gap S. The reduction in fuel speed was completely suppressed. When the fuel having a high flow velocity is injected and passes through the annular gap S in this manner, a large negative pressure is generated on the inner peripheral surface of the air-fuel mixture forming hole 40D, while the tip surface 40C of the cover 40 is generated. Alternatively, since the outer peripheral side surface 40F of the cover 40 faces the inside of the intake pipe, a large negative pressure is not generated in those portions, and the end surface 40C of the cover 40 or the outer peripheral side surface 40F is connected via the air intake passage 40E. It does not increase the negative pressure in the air chamber F. According to the above, the opening of the air suction passage 40H to the air-fuel mixture forming hole 40D and the air chamber F
A large pressure difference is generated between the air-fuel mixture and the air-fuel mixture forming hole 40D. And the mixture forming hole 40
The air sucked into D is sufficiently mixed with the outer portion of the fuel passing through the annular gap S and having a high flow velocity. On the other hand, when the fuel having a high flow velocity is injected and passes through the annular gap S, the outer peripheral side surface 6 of the needle portion 6A is
A large negative pressure is generated in D, and on the other hand, a large negative pressure is not generated in the tip surface 6C of the needle portion 6A because it faces the inside of the intake pipe. Thus, the needle portion 6A
Since a large pressure difference is generated between the outer peripheral side surface 6D and the tip end surface 6C, an air flow is generated from the air suction passage 11A as the air passage 11 provided in the needle portion 6A toward the air suction passage 11B, and the air suction passage Air which is sucked into and mixed with the inward portion of the injected fuel flowing from the outer peripheral side surface 6D of the needle portion 6A from 11B, whereby the air can be mixed well with the injected fuel and the atomization of the fuel can be significantly improved. Is. Particularly, the columnar portion 40P is projected upward from the bottom portion 40B of the cover 40, and the upper end surface 40R of the columnar portion 40P is projected.
Since the air suction passage 40H is provided as a concave portion and the tip end surface 9D of the valve body housing 9 is brought into contact with the upper end surface 40R of the columnar portion 40P of the cover 40, the air suction passage 40H has the injection hole 9A.
Can be directly opened to the air-fuel mixture forming hole, and the air suction passage 11B provided in the needle portion 6A can be connected to the annular gap S.
The air is sucked out by the injected fuel having a very high speed injected from the injection hole 9A, and further, before the fuel injected from the injection hole 9A diffuses (immediately before the diffusion), The air can be mixed with the air, and the fuel can be effectively atomized by mixing the air by utilizing the diffusion energy of the fuel during the subsequent diffusion of the fuel.

【００２６】又、空気吸出路４０Ｈを複数設け、混合気
形成孔４０Ｄに対して複数の空気吸出路４０Ｈを開口さ
せると、混合気形成孔４０Ｄ内を流れる噴射燃料の全周
囲に渡って均一に空気を混合できるもので燃料の微粒化
が促進される。Further, when a plurality of air suction passages 40H are provided and a plurality of air suction passages 40H are opened with respect to the air-fuel mixture forming holes 40D, the injected fuel flowing in the air-fuel mixture forming holes 40D is evenly distributed all around. It can mix air and promotes atomization of fuel.

【００２７】又、図１７に示される如く、円形状をなす
混合気形成孔４０Ｄの接線方向に空気吸出路４０Ｈを開
口すると、混合気形成孔４０Ｄ内へ吸出される空気は混
合気形成孔４０Ｄの円周方向に沿って吸出されるもの
で、これによると混合気形成孔４０Ｄ内を通過する燃料
にスワールを起こすことができるもので、より一層燃料
と空気との混合を促進できるものであって更に燃料の微
粒化を向上できる。この時空気吸出路４０Ｈを複数設け
ることは一層好ましい。As shown in FIG. 17, when the air suction passage 40H is opened in the tangential direction of the circular air-fuel mixture forming hole 40D, the air sucked into the air-fuel mixture forming hole 40D is mixed with the air-fuel mixture forming hole 40D. Is sucked out along the circumferential direction of the fuel cell, which can cause swirl in the fuel passing through the air-fuel mixture forming hole 40D, and can further promote the mixing of the fuel and air. The atomization of fuel can be further improved. At this time, it is more preferable to provide a plurality of air suction passages 40H.

【００２８】又、ニードル部６Ａの外周側面６Ｄに穿設
される空気吸出路１１Ｂをニードル部６Ａの横断面にお
いて複数設けること、ニードル部６Ａの軸方向において
多段に設けること、及びニードル部６Ａの横断面におい
て複数で且つニードル部６Ａの軸方向において多段に設
けることによると、燃料の微粒化の向上に寄与する。In addition, a plurality of air suction passages 11B formed in the outer peripheral side surface 6D of the needle portion 6A are provided in the cross section of the needle portion 6A, and are provided in multiple stages in the axial direction of the needle portion 6A. The plurality of cross-sections and the multi-stage arrangement in the axial direction of the needle portion 6A contribute to improvement in atomization of fuel.

【００２９】[0029]

【発明の効果】本発明になる燃料噴射弁によると、カバ
ーに穿設せる混合気形成孔と弁体のニードル部の先端部
によって、噴射孔に連なる環状の間隙をカバーに形成
し、この環状の間隙に向けて空気通路の一端を開口し、
他端をカバーの先端面又は外周側面に開口し、更にニー
ドル弁部には、一端がニードル弁部の外周側面に開口
し、他端がニードル弁部の先端に開口する空気通路を設
けたので、噴射孔から噴射される噴射燃料の燃料速度の
低下を抑止でき、この噴射燃料によって環状の間隙内に
充分なる空気を吸入することができるとともに噴射燃料
の外方部分及び内方部分に空気を良好に混合できたもの
で燃料の微粒化を著しく向上できたものである。又、混
合気形成孔に開口するカバー及びニードル弁部に設けた
空気通路は、環状の間隙内にあって、しかも混合気形成
孔に連なって開口する噴射孔の開口部の近傍に開口でき
るので噴射孔より噴射される燃料速度の極めて速い部分
の燃料の外方部分及び内方部分に空気通路からの空気を
吸入でき、更には環状の間隙内を拡散しつつ流下する燃
料の拡散エネルギーによって燃料を微細にしつつ空気と
良好に混合できたものである。更に、カバーは従来の燃
料噴射弁にあってもニードル部を保護する為に装着され
るもので、本発明にあってはこのカバーに混合気形成
孔、及び空気通路を設け、更にニードル部も従来より備
えるもので、このニードル部に空気通路を設けたもので
新たな部品を必要としないことから製品コストの上昇を
抑止できたものである。又、燃料噴射弁を装着する吸気
管等に何等の変更を必要としない。これは燃料噴射弁の
先端に単にカバーを装着したにすぎないからである。従
って本発明の燃料噴射弁は従来のものと互換性を有し極
めて容易にその実施（装着）を図ることができる。According to the fuel injection valve of the present invention, an annular gap communicating with the injection hole is formed in the cover by the air-fuel mixture forming hole formed in the cover and the tip of the needle portion of the valve body. Open one end of the air passage toward the gap of
Since the other end is opened to the tip surface or the outer peripheral side surface of the cover, and further, the needle valve portion is provided with an air passage whose one end is opened to the outer peripheral side surface of the needle valve portion and the other end is opened to the tip end of the needle valve portion. , It is possible to suppress a decrease in the fuel velocity of the injected fuel injected from the injection hole, and it is possible to suck sufficient air into the annular gap by this injected fuel and to inject air into the outer and inner parts of the injected fuel. The mixture was well mixed and the atomization of the fuel was remarkably improved. Further, the air passage provided in the cover and the needle valve portion which open to the mixture forming hole can be opened in the annular gap and in the vicinity of the opening of the injection hole which is continuous with the mixture forming hole. Air from the air passage can be sucked into the outer and inner portions of the fuel injected from the injection hole at an extremely high fuel velocity, and the fuel can be diffused through the annular gap while diffusing energy of the fuel. It was able to mix well with air while making it fine. Further, the cover is attached to protect the needle portion even in the conventional fuel injection valve. In the present invention, the cover is provided with the air-fuel mixture forming hole and the air passage, and the needle portion is also provided. Since the needle is provided with an air passage in the related art and no new parts are required, an increase in product cost can be suppressed. Further, no change is required in the intake pipe or the like to which the fuel injection valve is attached. This is because the cover is simply attached to the tip of the fuel injection valve. Therefore, the fuel injection valve of the present invention is compatible with the conventional one and can be implemented (installed) very easily.

[Brief description of drawings]

図は本発明になる燃料噴射弁の実施例を示す。 The drawings show an embodiment of the fuel injection valve according to the present invention.

【図１】本発明になる燃料噴射弁の一実施例を示す縦断
面図であって、第一の実施例のカバーが装着された。FIG. 1 is a vertical sectional view showing an embodiment of a fuel injection valve according to the present invention, in which a cover of the first embodiment is attached.

【図２】図１のＡ部の拡大断面図である。FIG. 2 is an enlarged cross-sectional view of a portion A of FIG.

【図３】カバーの第一の実施例を示す縦断面図である。FIG. 3 is a vertical cross-sectional view showing a first embodiment of the cover.

【図４】図３の上部平面図である。FIG. 4 is a top plan view of FIG.

【図５】カバーの第一の実施例における空気吸入路の他
の例を示す上部平面図である。FIG. 5 is a top plan view showing another example of the air suction passage in the first embodiment of the cover.

【図６】カバー及びニードル弁部の第二の実施例を示す
縦断面図である。FIG. 6 is a vertical cross-sectional view showing a second embodiment of the cover and the needle valve portion.

【図７】図６に示されたカバーの縦断面図である。7 is a vertical cross-sectional view of the cover shown in FIG.

【図８】図７の上部平面図である。8 is a top plan view of FIG. 7. FIG.

【図９】カバー及びニードル弁部の第三の実施例を示す
縦断面図である。FIG. 9 is a vertical sectional view showing a third embodiment of the cover and the needle valve portion.

【図１０】図９に示されたカバーの縦断面図である。10 is a vertical cross-sectional view of the cover shown in FIG.

【図１１】図１０の上部平面図である。11 is a top plan view of FIG.

【図１２】カバーの第三の実施例の変形例を示す縦断面
図である。FIG. 12 is a vertical sectional view showing a modified example of the third embodiment of the cover.

【図１３】図１２の上部平面図である。13 is a top plan view of FIG.

【図１４】カバー及びニードル弁部の第四の実施例を示
す縦断面図である。FIG. 14 is a vertical cross-sectional view showing a fourth embodiment of the cover and the needle valve portion.

【図１５】図１４に示されたカバーの縦断面図である。15 is a vertical cross-sectional view of the cover shown in FIG.

【図１６】図１５の上部平面図である。16 is a top plan view of FIG.

【図１７】カバーの第四の実施例の変形例を示す上部平
面図である。FIG. 17 is a top plan view showing a modification of the fourth embodiment of the cover.

[Explanation of symbols]

１本体ハウジング６弁体６Ａニードル部６Ｂ弁部６Ｃ先端面６Ｄ外周側面９弁体ハウジング９Ａ噴射孔９Ｄ弁体ハウジングの先端面１０，２０，３０，４０カバー１０Ｂ，２０Ｂ，３０Ｂ，４０Ｂ底部１０Ｃ，２０Ｃ，３０Ｃ，４０Ｃ先端面１０Ｄ，２０Ｄ，３０Ｄ，４０Ｄ混合気形成孔１０Ｅ，２０Ｅ，３０Ｅ，４０Ｅ空気吸入路１０Ｆ，２０Ｆ，３０Ｆ，４０Ｆ外周面１１空気通路１１Ａ空気吸入路１１Ｂ空気吸出路３０Ｈ空気吸出溝４０Ｐ円柱部４０Ｒ上端面４０Ｔ外形部４０Ｈ空気吸出路Ｓ環状の間隙 1 Main body housing 6 Valve body 6A Needle part 6B Valve part 6C Tip surface 6D Outer peripheral side surface 9 Valve body housing 9A Injection hole 9D Tip surface of valve body housing 10, 20, 30, 40 Cover 10B, 20B, 30B, 40B Bottom part 10C, 20C, 30C, 40C Tip surface 10D, 20D, 30D, 40D Air-fuel mixture forming hole 10E, 20E, 30E, 40E Air suction passage 10F, 20F, 30F, 40F Outer peripheral surface 11 Air passage 11A Air suction passage 11B Air suction passage 30H Air Suction groove 40P Cylindrical part 40R Upper end surface 40T External shape part 40H Air suction path S Annular gap

Claims

[Claims]

1. A valve body housing having an injection hole at its tip, which connects the injection hole and a valve chamber provided inside with a valve seat, and a main body housing connected to a rear end of the valve housing. A valve body that is axially movably arranged in the valve chamber of the valve body housing and has a needle portion that is inserted into the injection hole at its tip and projects from the injection hole, and a valve portion that can be seated on the valve seat. A solenoid for driving the valve element in the main body housing in the axial direction, and a cylindrical cover is arranged to face the tip end surface of the valve element housing. An air-fuel mixture forming hole, one end of which opens on the tip end surface of the cover and the other end of which opens corresponding to the injection hole of the valve body housing, and into which the tip end of the needle portion of the valve body can be inserted, and one end of which is the air-fuel mixture forming hole. Open at the other end and the other end An air intake passage opening to the peripheral side surface is provided, and on the other hand, in the needle portion of the valve body, an air passage having one end opening to the tip end surface of the needle portion and the other end opening to the outer peripheral side surface of the needle portion is formed. Characteristic fuel injection valve.

2. A valve body housing, which has an injection hole at its tip and which connects the injection hole and a valve chamber provided inside by a valve seat, and a main body housing connected to a rear end of the valve housing. , A valve portion that is axially movably disposed in the valve housing of the valve body housing, and has a needle portion that is inserted into the injection hole at the tip end thereof and that projects from the tip end surface of the valve body housing and a valve portion that can be seated on the valve seat. In a fuel injection valve including a valve body having the valve body and a solenoid for axially driving the valve body in a main body housing, a cylindrical cover is arranged opposite to a front end surface of the valve body housing with a gap. To form an air chamber, one end of the cover is opened to the tip surface of the cover, the other end is opened to the air chamber and a mixture forming hole into which the tip of the needle portion of the valve body can be inserted, Located outside the mixture forming hole, An air intake path having an end opening to the tip surface or the outer peripheral side surface of the cover and the other end opening to the air chamber is provided, while the needle portion of the valve body is opened, and one end is opened to the tip surface of the needle portion. A fuel injection valve, characterized in that an air passage whose end opens to the outer peripheral side surface of the needle portion is formed.

3. A valve body housing, which has an injection hole at its tip and which connects the injection hole and a valve chamber provided inside by a valve seat, and a main body housing connected to the rear end of the valve housing. A valve body that is axially movably arranged in the valve chamber of the valve body housing and has a needle portion that is inserted into the injection hole at its tip and projects from the injection hole, and a valve portion that can be seated on the valve seat. A solenoid for driving the valve element in the main body housing in the axial direction, and a bottom portion of a cylindrical cover is arranged in contact with the tip end surface of the valve element housing. In the cover, one end is opened to the tip end surface of the cover, the other end is connected to the injection hole of the valve body housing and is opened to the bottom part, and the tip end of the needle part of the valve body can be inserted, and the cover. Is formed in the bottom of the An air suction groove that opens, and an air suction path that is on the outer side of the air-fuel mixture forming hole and has one end that opens to the tip surface or the outer peripheral side surface of the cover and the other end that opens to the air suction groove.
On the other hand, the fuel injection valve is characterized in that an air passage is formed in the needle portion of the valve body, one end of which is opened to a tip end surface of the needle portion and the other end of which is opened to an outer peripheral side surface of the needle portion.

4. A valve body housing, which has an injection hole at its tip and which connects the injection hole and a valve chamber provided inside by a valve seat, and a main body housing connected to a rear end of the valve housing. A valve body that is axially movably arranged in the valve chamber of the valve body housing and has a needle portion that is inserted into the injection hole at its tip and projects from the injection hole, and a valve portion that can be seated on the valve seat. And a solenoid for driving the valve element in the main body housing in the axial direction, the valve element being provided on a tubular cover arranged to face a front end surface of the valve element housing. The bottom facing the front end surface of the housing, the cylindrical portion that is approximately in the center of the cover and protrudes from the bottom, one end at the center of the cylindrical portion that opens to the front end surface of the cover, and the other end is the injection of the valve housing. Open in the upper end surface of the cylinder part in a row with the hole With the air-fuel mixture forming hole into which the tip of the needle portion of the valve element can be inserted, one end of the columnar portion is opened to the outer shape of the columnar portion, and the other end is opened to the air-fuel mixture forming hole. An air intake passage having a bottom portion outside the columnar portion, one end of which opens to the tip end surface or the outer peripheral side surface of the cover and the other end of which opens to the bottom portion, and the top end surface of the columnar portion of the cover is provided with a valve body housing. The bottom of the cover and the tip surface of the valve body housing form an air chamber by abutting on the tip surface of the valve body.On the other hand, at the needle portion of the valve body, one end is opened to the tip surface of the needle portion and the other end is the needle. A fuel injection valve characterized in that an air passage opening to an outer peripheral side surface of the portion is formed.

5. The fuel injection valve according to claim 1, wherein one end of the air intake passage is opened in a tangential direction of the mixture forming hole.

6. The fuel injection valve according to claim 3, wherein the air suction groove is opened in a tangential direction of the mixture forming hole.

7. The fuel injection valve according to claim 4, wherein the air suction passage is opened in the tangential direction of the mixture forming hole.

8. The method according to claim 1, wherein the opening of the air passage provided in the needle portion to the outer peripheral side surface of the needle portion is opened in multiple stages in the axial direction of the needle portion.
Alternatively, the fuel injection valve according to claim 4.

9. A plurality of openings to the outer peripheral side surface of the needle part of the air passage provided in the needle part are formed in a plurality of cross-sections of the needle part. 4. The fuel injection valve according to 4.

10. The opening of the air passage provided in the needle portion to the outer peripheral side surface of the needle portion is plural in the cross section of the needle portion, and is opened in multiple stages in the axial direction of the needle portion. Alternatively, the fuel injection valve according to claim 2, claim 3, or claim 4.