JPH1193800A - Accumulator fuel injection valve - Google Patents
Accumulator fuel injection valveInfo
- Publication number
- JPH1193800A JPH1193800A JP25201697A JP25201697A JPH1193800A JP H1193800 A JPH1193800 A JP H1193800A JP 25201697 A JP25201697 A JP 25201697A JP 25201697 A JP25201697 A JP 25201697A JP H1193800 A JPH1193800 A JP H1193800A
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- valve
- fuel
- fuel injection
- needle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
- F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
- F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
- F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
-
- 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
- F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
- F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
- F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、内燃機関に適用さ
れる蓄圧式の燃料噴射装置に係り、特に蓄圧式燃料噴射
装置に使用さ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 pressure-accumulation type fuel injection device applied to an internal combustion engine, and more particularly to a fuel injection valve used for a pressure-accumulation type fuel injection device.
【０００２】[0002]
【従来の技術】従来の蓄圧式燃料噴射弁としては、特開
平７−２９３３８７号公報に記載されているものがあ
る。これは、ソレノイド弁（油圧制御弁）の開閉により
ニードルの背圧を制御することによってニードルを移動
させて噴孔を開閉し、コモンレール（蓄圧容器）から供
給される高圧燃料を調量して噴射するものである。しか
しながら、コモンレールは、それをエンジンに組み込む
上から、きわめて大きな容積とすることは不可能である
し、燃料噴射弁（インジェクタ）の近傍に設けるか、あ
るいは燃料噴射弁に直接に接続することはきわめて困難
である。そのため、従来の燃料噴射弁による蓄圧式燃料
噴射装置においては、高圧燃料の供給が燃料の噴射に十
分に追従せず、噴射開始直後から噴射の中期にかけて、
実噴射圧がかなり大幅に低下する結果、燃料の微粒化が
十分に進まないので、空気との混合状態が不完全となっ
て燃焼状態が悪化し、大量のスモークを発生する場合が
ある。また、近年の排気規制の強化に応じてスモーク排
出量を一定レベル以下に抑えた場合には、エンジンの出
力が大幅に低下するという問題がある。噴射圧の変動の
問題はコモンレールの圧力を高めることによって或る程
度解決することができるが、そのためにはコモンレール
その他の耐圧性を高める必要上、それらが大型化すると
いう問題を伴う。2. Description of the Related Art As a conventional pressure-accumulating fuel injection valve, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 7-29387. This is achieved by controlling the back pressure of the needle by opening and closing a solenoid valve (hydraulic control valve) to move the needle to open and close the injection hole, and to measure and inject high-pressure fuel supplied from a common rail (accumulator). Is what you do. However, since the common rail cannot be built into the engine, it is impossible to increase the volume of the common rail, and it is extremely difficult to provide the common rail near the fuel injection valve (injector) or to connect it directly to the fuel injection valve. Have difficulty. Therefore, in the conventional pressure-accumulation fuel injection device using a fuel injection valve, the supply of high-pressure fuel does not sufficiently follow the injection of fuel, and from the start of injection to the middle of injection,
As a result of a substantial decrease in the actual injection pressure, the atomization of the fuel does not proceed sufficiently, so that the mixing state with air is incomplete and the combustion state deteriorates, and a large amount of smoke may be generated. In addition, if the amount of smoke emission is suppressed to a certain level or less in accordance with the recent tightening of exhaust regulations, there is a problem that the output of the engine is greatly reduced. The problem of the fluctuation of the injection pressure can be solved to some extent by increasing the pressure of the common rail. However, for that purpose, it is necessary to increase the pressure resistance of the common rail and other parts, and there is a problem that they become large.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、従来技術に
おける前述のような問題に対処して、体積が大きいため
に燃料噴射弁から多少とも離して設置する必要があるコ
モンレールのような蓄圧容器をさらに高圧化することに
よって一層大型化することなく、簡単な手段によって噴
射圧力の変動を効果的に抑制することができる、改良さ
れた蓄圧式燃料噴射弁を提供することを目的としてい
る。SUMMARY OF THE INVENTION The present invention addresses the above-mentioned problems in the prior art and provides a pressure accumulator, such as a common rail, which must be installed at some distance from the fuel injector due to its large volume. It is an object of the present invention to provide an improved pressure-accumulation type fuel injection valve which can effectively suppress the fluctuation of the injection pressure by simple means without increasing the size by further increasing the pressure.
【０００４】[0004]
【課題を解決するための手段】本発明は、前記の課題を
解決するための手段として、特許請求の範囲の各請求項
に記載された蓄圧式燃料噴射弁を提供する。According to the present invention, there is provided a pressure-accumulation type fuel injection valve as a means for solving the above-mentioned problems.
【０００５】本発明は基本的に、噴孔を開閉するニード
ルと、噴孔の近傍で高圧燃料を貯溜するとともにそこに
作用する油圧力によってニードルを押し上げる油だまり
と、外部のコモンレールから油だまりへ高圧燃料を導入
する燃料通路とを備えている蓄圧式燃料噴射弁におい
て、油だまりから見てコモンレールに連通する燃料通路
および噴孔に連通する燃料通路とは別に、一端において
油だまりに連通して高圧燃料を導く制御通路と、制御通
路の他端に連通し高圧燃料を貯溜する容積一定の空間か
らなるリザーバとを備えていることを特徴とする。The present invention basically comprises a needle for opening and closing a nozzle, an oil reservoir for storing high-pressure fuel in the vicinity of the nozzle and pushing up the needle by an oil pressure acting thereon, and an oil reservoir from an external common rail to an oil reservoir. In a pressure accumulating fuel injection valve having a fuel passage for introducing high-pressure fuel, a fuel passage communicating with the common rail and a fuel passage communicating with the injection hole as viewed from the oil reservoir, and communicating with the oil reservoir at one end. It is characterized by comprising a control passage for guiding high-pressure fuel, and a reservoir having a fixed volume and communicating with the other end of the control passage for storing high-pressure fuel.
【０００６】従って、燃料噴射弁の内部の油だまりと、
外部のコモンレールだけでは燃料噴射に伴う噴射圧の変
動を十分に抑制することができない時でも、本発明の蓄
圧式燃料噴射弁においては、制御通路の長さと、リザー
バの容積を適当に設定することによって、個々の燃料噴
射弁において圧力変動によって噴射圧が低下する時期
と、その燃料噴射弁の油だまりから制御通路を通ってリ
ザーバへ到達する圧力波の高圧部分がリザーバから同じ
制御通路を通って再び油だまりへ戻って来る時期とを一
致させることにより、噴射圧の著しい低下を阻止するこ
とができる。Accordingly, the oil pool inside the fuel injection valve and
Even when the fluctuation of the injection pressure due to the fuel injection cannot be sufficiently suppressed only by the external common rail, in the accumulator type fuel injection valve of the present invention, the length of the control passage and the volume of the reservoir must be appropriately set. Due to this, when the injection pressure is reduced due to pressure fluctuations in the individual fuel injection valves, the high pressure portion of the pressure wave reaching the reservoir from the reservoir of the fuel injection valve through the control passage passes from the reservoir through the same control passage. By matching the timing of returning to the oil sump again, a remarkable decrease in the injection pressure can be prevented.
【０００７】それによって、燃料噴射弁における噴射圧
の変化による噴射率の変動を効果的に抑制することが可
能となり、燃料の微粒化が悪化するのを防止して、エン
ジンにおける良好な燃焼状態を維持することができるの
で、スモークの排出量を減少させることができる。ま
た、コモンレールの圧力を高めて噴射圧の変動を抑える
従来技術に比べて、コモンレールや燃料噴射弁の燃料油
圧に対する強度を比較的小さくすることができること
と、高圧燃料ポンプの負荷も小さくなるため、燃料噴射
装置全体が小型で安価なものとなる。As a result, it is possible to effectively suppress a change in the injection rate due to a change in the injection pressure in the fuel injection valve, to prevent the atomization of the fuel from deteriorating, and to improve the combustion state in the engine. Since it can be maintained, the amount of smoke emission can be reduced. Also, as compared with the conventional technology in which the pressure of the common rail is increased to suppress the fluctuation of the injection pressure, the strength of the common rail and the fuel injection valve with respect to the fuel oil pressure can be made relatively small, and the load on the high-pressure fuel pump also becomes small. The whole fuel injection device is small and inexpensive.
【０００８】具体的に、本発明の蓄圧式燃料噴射弁は、
前述の基本的な構成に加えて、コマンドピストンとニー
ドルを閉弁方向へ付勢する弾性手段と、コマンドピスト
ンの一側に形成される制御室と、ニードルを進退作動さ
せるために制御室の圧力を制御する油圧制御弁をも備え
ているものとすることができる。さらに、油圧制御弁は
電磁弁とすることができ、油圧制御弁を二方向弁として
実施する場合は、制御室へ導入される高圧燃料の一部を
油圧制御弁によって低圧側へ逃がすことによって、ま
た、油圧制御弁を三方向弁として実施する場合は、高圧
と低圧を切り換えて制御室へ供給することにより、制御
室の油圧を変化させてニードルを開弁または閉弁方向へ
移動させる。Specifically, the accumulator type fuel injection valve of the present invention
In addition to the basic configuration described above, an elastic means for urging the command piston and the needle in the valve closing direction, a control chamber formed on one side of the command piston, and a pressure in the control chamber for moving the needle forward and backward. May be provided with a hydraulic control valve for controlling the pressure. Furthermore, the hydraulic control valve can be an electromagnetic valve, and when the hydraulic control valve is implemented as a two-way valve, a part of the high-pressure fuel introduced into the control chamber is released to the low-pressure side by the hydraulic control valve. When the hydraulic control valve is implemented as a three-way valve, the high pressure and the low pressure are switched and supplied to the control chamber, thereby changing the hydraulic pressure in the control chamber to move the needle in the valve opening or valve closing direction.
【０００９】リザーバは、弁本体の肉厚部分に形成され
た円形の穴からなる空間を、穴の口に中空のプラグを螺
着することによって比較的簡単に構成することができる
が、リザーバはそれ以外の形状、構造とすることもでき
る。実験の結果、リザーバの空間の容積は０．３ cm3以
上あれば、十分満足な結果が得られる。[0009] The reservoir can be formed relatively simply by screwing a hollow plug into the opening of a circular hole formed in a thick portion of the valve body by screwing a hollow plug. Other shapes and structures are also possible. As a result of the experiment, a satisfactory result can be obtained if the volume of the reservoir space is 0.3 cm 3 or more.
【００１０】[0010]
【発明の実施の形態】図２は本発明の燃料噴射弁が適用
される蓄圧式燃料噴射装置の全体構成を示した図であ
る。燃料タンク１より低圧ポンプ２によって汲み上げら
れた燃料は高圧ポンプ３へ供給される。高圧ポンプ３か
ら吐出される高圧の燃料は、コモンレール４において蓄
圧され、エンジンの各気筒ごとに設けられた燃料噴射弁
５へ供給される。コモンレール４には圧力センサ６が取
りつけられており、その他各種のセンサからの信号が入
力される電子式制御装置（ＥＣＵ）により、エンジンの
運転条件に最適となるように高圧ポンプ３をコントロー
ルして、コモンレール４内を所望の圧力に調整する。FIG. 2 is a diagram showing the overall configuration of a pressure accumulating fuel injection device to which the fuel injection valve of the present invention is applied. The fuel pumped from the fuel tank 1 by the low pressure pump 2 is supplied to the high pressure pump 3. The high-pressure fuel discharged from the high-pressure pump 3 is accumulated in the common rail 4 and supplied to a fuel injection valve 5 provided for each cylinder of the engine. A pressure sensor 6 is mounted on the common rail 4, and the high pressure pump 3 is controlled by an electronic control unit (ECU) to which signals from various other sensors are input so as to be optimal for the operating conditions of the engine. The inside of the common rail 4 is adjusted to a desired pressure.
【００１１】コモンレール４と燃料噴射弁５は高圧配管
８により連結されているが、その長さはそれぞれのエン
ジンの搭載条件により変化する。燃料噴射弁５もＥＣＵ
７からエンジンの運転条件に合わせた最適の噴射パルス
により駆動される。Although the common rail 4 and the fuel injection valve 5 are connected by a high-pressure pipe 8, the length varies depending on the mounting conditions of each engine. Fuel injection valve 5 is also ECU
From 7, it is driven by an optimal injection pulse according to the operating conditions of the engine.
【００１２】図１に本発明の特徴部分である燃料噴射弁
５の断面を示す。その要部の詳細は図３に拡大して示さ
れている。配管８に通じる燃料インレット１２よりオリ
フィススクリュ２１の中に設けられたインオリフィス２
０を介して、制御室１３へ高圧燃料が導入される。制御
室１３はアウトオリフィス１４を介して油圧制御弁１５
へ通じている。FIG. 1 shows a cross section of a fuel injection valve 5 which is a feature of the present invention. The details of the main part are shown in an enlarged manner in FIG. The orifice 2 provided in the orifice screw 21 from the fuel inlet 12 leading to the pipe 8
The high-pressure fuel is introduced into the control chamber 13 via the control valve 0. The control chamber 13 is provided with a hydraulic control valve 15 through an out orifice 14.
Leading to
【００１３】図示例における油圧制御弁１５は、制御室
１３の高圧燃料の一部を低圧通路１９へ逃がすことによ
って制御室１３の圧力を変化させる所謂二方向弁であっ
て、弁体５１と、その中に摺動自在に挿入されたバラン
スロッド５２などから成っている。バランスロッド５２
は、弁体５１を押し上げるように作用する制御室１３の
燃料油圧に対抗して、その下面へ導入する同じ油圧によ
って弁体５１を押し下げることにより、ソレノイド６０
の必要な出力を軽減する効果を有する。バランスロッド
５２の直径は、弁体５１が係合するシート部５４の直径
よりも小さくする。通常はバルブスプリング５３により
弁体５１は下方へ付勢されており、その下方の円錐状の
先端がシート部５４に着座して、制御室１３と低圧通路
１９との間を遮断している。The hydraulic control valve 15 in the illustrated example is a so-called two-way valve that changes the pressure in the control chamber 13 by allowing a part of the high-pressure fuel in the control chamber 13 to escape to the low-pressure passage 19. The balance rod 52 is slidably inserted therein. Balance rod 52
Is pressed against the fuel oil pressure of the control chamber 13 acting to push up the valve element 51 and depresses the valve element 51 by the same oil pressure introduced to the lower surface of the control chamber 13.
This has the effect of reducing the required output. The diameter of the balance rod 52 is smaller than the diameter of the seat portion 54 with which the valve body 51 is engaged. Normally, the valve body 51 is urged downward by the valve spring 53, and the lower conical tip of the valve body 51 is seated on the seat portion 54 to shut off the space between the control chamber 13 and the low-pressure passage 19.
【００１４】オリフィススクリュ２１は、さらに燃料噴
射弁５の本体５０に穿孔して形成された通路１６へも通
じており、高圧燃料はノズル１７に形成された油だまり
１８へ導入されている。ノズル１７にはニードル７１が
上下方向に摺動自在に挿入されており、ニードル７１は
ニードルスプリング７３によって下方へ付勢されて噴孔
を塞いでいる。ニードル７１の上には、コマンドピスト
ン７４が上下方向に一体となって移動するように設けら
れており、その上端面は制御室１３に臨んでいる。The orifice screw 21 also communicates with a passage 16 formed by piercing the main body 50 of the fuel injection valve 5, and high-pressure fuel is introduced into a sump 18 formed in the nozzle 17. A needle 71 is inserted into the nozzle 17 so as to be slidable in the vertical direction. The needle 71 is urged downward by a needle spring 73 to close the injection hole. A command piston 74 is provided on the needle 71 so as to move integrally in the vertical direction, and the upper end face thereof faces the control chamber 13.
【００１５】本発明の特徴として、油だまり１８からさ
らに制御通路９を介して、一定容積のリザーバ１０へ高
圧燃料が導入されるように構成されている。A feature of the present invention is that high-pressure fuel is introduced from the sump 18 to the reservoir 10 having a constant volume via the control passage 9.
【００１６】ここで、リザーバ１０の構造および配置に
ついてより詳細に説明する。通常、体積の大きいコモン
レール４は、エンジンへの装着の制約から油だまり１８
の近傍に配置することができないので、コモンレール４
からの高圧燃料の供給遅れを防止するために、本発明に
おいてはリザーバ１０を、燃料噴射弁５の本体５０の内
部に設けた点に特徴がある。Here, the structure and arrangement of the reservoir 10 will be described in more detail. Usually, the large-volume common rail 4 has an oil sump 18 due to restrictions on mounting to the engine.
Cannot be placed near the common rail 4
The present invention is characterized in that the reservoir 10 is provided inside the main body 50 of the fuel injection valve 5 in order to prevent supply delay of the high pressure fuel from the fuel injection valve 5.
【００１７】図１及び図３に示す例では、インジェクタ
の本体５０の中に通路１６と平行に制御通路９が穿孔形
成され、その上方に延びた先端が、制御室１３の近傍の
本体５０の厚肉部に形成されたリザーバ１０に連通して
いる。リザーバ１０は制御通路９以外のものには開口し
ない行き止まりの小さな空洞となっており、この場合は
円形の穴として形成されるとともに、中空のボルト状の
プラグ１１をリザーバ１０の穴の一部に形成された雌ね
じ部に螺入することによって外部から閉塞されている。
ただし、リザーバ１０の形状は円形の穴に限られる訳で
はない。In the example shown in FIGS. 1 and 3, a control passage 9 is formed in the injector body 50 in parallel with the passage 16, and a tip extending above the control passage 9 is formed in the body 50 near the control chamber 13. It communicates with the reservoir 10 formed in the thick part. The reservoir 10 is a small dead-end cavity that does not open to anything other than the control passage 9. In this case, the reservoir 10 is formed as a circular hole, and a hollow bolt-shaped plug 11 is inserted into a part of the hole of the reservoir 10. It is closed from the outside by screwing into the formed female screw part.
However, the shape of the reservoir 10 is not limited to a circular hole.
【００１８】ここで圧力波の伝達速度ａは、Ｋを体積弾
性率、ρを密度とすれば、 ａ＝（Ｋ／ρ）1/2 として表すことができる。Here, the transmission velocity a of the pressure wave can be expressed as a = (K / ρ) 1/2 where K is the bulk modulus and ρ is the density.
【００１９】たとえば、油だまり１８からの圧力波の高
圧部分がリザーバ１０に到達し、反射されて１００μｓ
後に再び油だまり１８へ帰って来ることにより、その圧
力が上昇するように設定しようとすれば、燃料である経
由のＫは２．５×１０9 Ｐａ（ａｔ １２０ＭＰａ）、
ρは８３７kg／ｍ3 であるから、ａ＝１７２８ｍ／ｓと
なるので、１００μｓならば、１７．２８cmの距離を必
要とする。この場合、圧力波は油だまり１８からリザー
バ１０までの制御通路９を往復するので、制御通路９の
長さはこの距離の半分の８．６４cmとすればよい。For example, the high pressure portion of the pressure wave from oil sump 18 reaches reservoir 10 and is reflected for 100 μs.
If it is attempted to set the pressure to rise by returning to the sump 18 later, K via the fuel is 2.5 × 10 9 Pa (at 120 MPa),
Since ρ is 837 kg / m 3 , a = 1728 m / s, so if 100 μs, a distance of 17.28 cm is required. In this case, since the pressure wave reciprocates in the control passage 9 from the oil reservoir 18 to the reservoir 10, the length of the control passage 9 may be set to half of this distance, that is, 8.64 cm.
【００２０】制御通路９の太さは、燃料噴射弁５の大き
さ（直径）の制約にもよるが、直径２mm以上とするの
が、リザーバ１０と油だまり１８との間の高圧燃料の流
れを円滑にするために好適である。Although the thickness of the control passage 9 depends on the size (diameter) of the fuel injection valve 5, the diameter of the control passage 9 should be 2 mm or more because the flow of the high-pressure fuel between the reservoir 10 and the oil sump 18. It is suitable for smoothing.
【００２１】また、リザーバ１０の容積は、圧力上昇を
大きくするためには大きいほどよいが、燃料噴射弁５の
大きさによる制約もあるため、大きな容積をとることは
一般に困難である。しかし、本発明のような構成では、
リザーバ１０までの制御通路９の容積も蓄圧作用を有す
るため、リザーバ１０の容積を０．３cm3 以上とするこ
とで、十分な噴射圧力の上昇が得られることを、発明者
らは実験によって確認している。The volume of the reservoir 10 is preferably as large as possible in order to increase the pressure rise. However, it is generally difficult to take a large volume because of the restriction due to the size of the fuel injection valve 5. However, in a configuration like the present invention,
Since the volume of the control passage 9 to the reservoir 10 also has a pressure accumulating action, the inventors have confirmed by experiments that a sufficient increase in injection pressure can be obtained by setting the volume of the reservoir 10 to 0.3 cm 3 or more. doing.
【００２２】次に、燃料噴射弁５の作動について説明す
る。噴射を開始する時、ＥＣＵ７は制御弁１５のソレノ
イド６０へ通電する。それによって弁体５１が吸引さ
れ、バルブスプリング５３の下方への付勢力に逆らって
弁体５１が上方へ移動する。従って、弁体５１の先端は
シート部５４から離座し、制御室１３内の高圧燃料が低
圧通路１９へ逃けるので、制御室１３の圧力が低下す
る。従って、コマンドピストン１４を下方へ押圧してい
た油圧による力がなくなり、油だまり１８に作用する油
圧による力が、ニードルスプリング７３の付勢力に打ち
かってニードル７１を上昇させる結果、噴孔７２から燃
料が噴射される。Next, the operation of the fuel injection valve 5 will be described. When starting the injection, the ECU 7 energizes the solenoid 60 of the control valve 15. As a result, the valve element 51 is sucked, and the valve element 51 moves upward against the downward biasing force of the valve spring 53. Therefore, the tip of the valve element 51 is separated from the seat portion 54, and the high-pressure fuel in the control chamber 13 escapes to the low-pressure passage 19, so that the pressure in the control chamber 13 decreases. Accordingly, the force by the oil pressure that has pressed the command piston 14 downward is eliminated, and the force by the oil pressure acting on the oil sump 18 strikes the urging force of the needle spring 73 to raise the needle 71, and as a result, the fuel Is injected.
【００２３】この時の噴射率（単位時間当りの噴射量）
の時間的変化と、それに対応する噴射圧の変動の状況を
示したものが図４および図５である。従来の蓄圧式燃料
噴射装置では、図４に示すように、噴射開始の直後にニ
ードル室２２（油だまり１８から噴孔７２までの燃料通
路）の圧力、即ち実噴射圧が大きく低下し、噴射の後期
になって漸く、コモンレール４からの供給によって圧力
が上昇する。Injection rate at this time (injection amount per unit time)
FIG. 4 and FIG. 5 show the time-dependent changes of the injection pressure and the corresponding changes in the injection pressure. In the conventional pressure-accumulating fuel injection device, as shown in FIG. 4, immediately after the start of the injection, the pressure in the needle chamber 22 (the fuel passage from the oil reservoir 18 to the injection hole 72), that is, the actual injection pressure is greatly reduced, and the injection is performed. Soon, the pressure rises due to the supply from the common rail 4.
【００２４】これに対して、制御通路９とリザーバ１０
を有する本発明の構成を用いることにより、図５に示す
ように、油だまり１８の近傍の容積の若干の増加の効果
として、噴射直後のニードル室２２の圧力の落込み量を
半減させることができる。さらに、リザーバ１０からの
圧力波により、噴射の初期から中期におけるニードル室
圧（噴射圧）を上昇させることが可能となる。On the other hand, the control passage 9 and the reservoir 10
By using the configuration of the present invention having the above, as shown in FIG. 5, as a result of slightly increasing the volume in the vicinity of the oil sump 18, the amount of pressure drop in the needle chamber 22 immediately after injection can be reduced by half. it can. Further, the pressure wave from the reservoir 10 can increase the needle chamber pressure (injection pressure) in the initial to middle stages of the injection.
【００２５】なお、図示の実施形態では二方向弁として
の電磁弁を油圧制御弁１５として使用しているが、必要
に応じて油圧制御弁１５には三方向電磁弁等を使用する
ことができる。この場合は、高圧側と低圧側を択一的に
制御室１３に接続して、その圧力を変化させることによ
り、ニードル７１を上下方向に駆動する。In the illustrated embodiment, a two-way solenoid valve is used as the hydraulic control valve 15, but a three-way solenoid valve or the like can be used as the hydraulic control valve 15 if necessary. . In this case, the needle 71 is driven up and down by selectively connecting the high pressure side and the low pressure side to the control chamber 13 and changing the pressure.
【図１】本発明の蓄圧式燃料噴射弁の実施形態を例示す
る縦断面図である。FIG. 1 is a longitudinal sectional view illustrating an embodiment of an accumulator type fuel injection valve of the present invention.
【図２】本発明の燃料噴射弁を適用する燃料噴射装置の
全体構成図である。FIG. 2 is an overall configuration diagram of a fuel injection device to which the fuel injection valve of the present invention is applied.
【図３】図１の一部を拡大して示す縦断面図である。FIG. 3 is an enlarged longitudinal sectional view showing a part of FIG. 1;
【図４】従来の燃料噴射弁の噴射特性と噴射圧の変動を
示す線図である。FIG. 4 is a graph showing a variation in injection characteristics and injection pressure of a conventional fuel injection valve.
【図５】本発明の燃料噴射弁の噴射特性と噴射圧の変動
を示す線図である。FIG. 5 is a diagram showing a variation in injection characteristics and an injection pressure of the fuel injection valve of the present invention.
３…高圧ポンプ ４…コモンレール ５…蓄圧式燃料噴射弁 ９…制御通路 １０…リザーバ １１…中空のプラグ １２…燃料インレット １３…制御室 １５…油圧制御弁 １６…燃料通路 １８…油だまり １９…低圧通路 ２０…インオリフィス ２２…ニードル室 ５０…燃料噴射弁の本体 ５１…弁体 ５２…バランスロッド ６０…ソレノイド ７１…ニードル ７２…噴孔 ７３…ニードルスプリング ７４…コマンドピストン DESCRIPTION OF SYMBOLS 3 ... High pressure pump 4 ... Common rail 5 ... Accumulation type fuel injection valve 9 ... Control passage 10 ... Reservoir 11 ... Hollow plug 12 ... Fuel inlet 13 ... Control room 15 ... Hydraulic control valve 16 ... Fuel passage 18 ... Oil sump 19 ... Low pressure Passage 20 ... In orifice 22 ... Needle chamber 50 ... Body of fuel injection valve 51 ... Valve body 52 ... Balance rod 60 ... Solenoid 71 ... Needle 72 ... Injection hole 73 ... Needle spring 74 ... Command piston
─────────────────────────────────────────────────────
────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成１０年５月２１日[Submission date] May 21, 1998
【手続補正１】[Procedure amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】特許請求の範囲[Correction target item name] Claims
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【特許請求の範囲】[Claims]
【手続補正２】[Procedure amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１９[Correction target item name] 0019
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【００１９】たとえば、油だまり１８からの圧力波の高
圧部分が制御通路９を通ってリザーバ１０に到達し、そ
こで反射されて１００μｓ後に再び油だまり１８へ帰っ
て来ることにより、その圧力が上昇するように設定しよ
うとすれば、燃料である軽油のＫは２．５×１０9 Ｐａ
（ａｔ １２０ＭＰａ）、ρは８３７kg／ｍ3 であるか
ら、ａ＝１７２８ｍ／ｓとなるので、１００μｓなら
ば、１７．２８cmの距離を必要とする。この場合、圧力
波は油だまり１８からリザーバ１０までの制御通路９を
往復するので、制御通路９の長さはこの距離の半分の
８．６４cmとすればよい。[0019] For example, high-pressure portion of the pressure wave from the oil reservoir 18 through the control path 9 reaches the reservoir 10, its
By being reflected come back to 100μs again after oil retention 18 this, if trying to set so that the pressure increases, the K light oil as fuel 2.5 × 10 9 Pa
(At 120 MPa) and ρ is 837 kg / m 3 , so a = 1728 m / s, so if 100 μs, a distance of 17.28 cm is required. In this case, since the pressure wave reciprocates in the control passage 9 from the oil reservoir 18 to the reservoir 10, the length of the control passage 9 may be set to half of this distance, that is, 8.64 cm.
Claims (8)
ドルと、噴射される高圧燃料を貯溜するとともにその油
圧力によって前記ニードルを開弁方向へ付勢する油だま
りと、外部に設けられた高圧燃料の貯溜蓄圧容器である
コモンレールから前記油だまりへ高圧燃料を導入する燃
料通路と、前記油だまりから見て前記コモンレールに連
通する前記燃料通路および前記噴孔に連通する燃料通路
とは別に一端において前記油だまりに連通して高圧燃料
を導く制御通路と、前記制御通路の他端に連通し高圧燃
料を貯溜する容積一定の空間からなるリザーバとを少な
くとも備えている蓄圧式燃料噴射弁。1. A needle for opening and closing an injection hole for injecting high-pressure fuel, an oil reservoir for storing the injected high-pressure fuel and urging the needle in the valve opening direction by the oil pressure thereof, and provided outside. One end is separate from a fuel passage for introducing high-pressure fuel from the common rail, which is a high-pressure fuel storage / accumulation container, to the oil sump, and a fuel passage communicating with the common rail and the injection hole as viewed from the oil sump. 2. The pressure accumulating fuel injection valve according to claim 1, further comprising: a control passage communicating with the oil sump and guiding high-pressure fuel; and a reservoir having a constant volume communicating with the other end of the control passage and storing the high-pressure fuel.
記ニードルと連動するコマンドピストンと、前記ニード
ルを閉弁方向へ付勢する弾性手段と、前記ニードルを前
記弾性手段とともに閉弁方向へ付勢するために前記コマ
ンドピストンの一側に形成されて制御された油圧力を導
入される制御室と、前記ニードルを進退作動させるため
に前記制御室の圧力を制御する油圧制御弁をも備えてい
る蓄圧式燃料噴射弁。2. In addition to the configuration described in claim 1, a command piston interlocked with the needle, elastic means for urging the needle in a valve closing direction, and a valve closing direction of the needle together with the elastic means. A control chamber formed on one side of the command piston for biasing and introducing a controlled hydraulic pressure, and a hydraulic control valve for controlling the pressure of the control chamber for moving the needle forward and backward. Accumulation type fuel injection valve provided.
御弁が電磁弁である蓄圧式燃料噴射弁。3. The accumulator-type fuel injection valve according to claim 1, wherein the hydraulic control valve is an electromagnetic valve.
前記油圧制御弁が前記制御室と低圧通路との間に挿入さ
れた二方向弁である蓄圧式燃料噴射弁。4. The method according to claim 1, wherein
An accumulator-type fuel injection valve, wherein the hydraulic control valve is a two-way valve inserted between the control chamber and a low-pressure passage.
部にバランスロッドを備えている蓄圧式燃料噴射弁。5. The pressure accumulating fuel injection valve according to claim 5, wherein the hydraulic control valve includes a balance rod inside.
前記油圧制御弁が前記制御室に高圧と低圧を選択的に導
入する三方向弁である蓄圧式燃料噴射弁。6. The method according to claim 1, wherein
An accumulator-type fuel injection valve, wherein the hydraulic control valve is a three-way valve that selectively introduces high pressure and low pressure into the control chamber.
前記リザーバの空間が弁本体の肉厚部分に形成された円
形の穴からなり、中空のプラグを前記穴に螺着すること
によって外部から遮断されている蓄圧式燃料噴射弁。7. The method according to claim 1, wherein
A pressure-accumulating fuel injection valve, wherein a space of the reservoir is formed of a circular hole formed in a thick portion of the valve body, and is blocked from the outside by screwing a hollow plug into the hole.
前記リザーバの空間の容積が０．３ cm3以上である蓄圧
式燃料噴射弁。8. The method according to claim 1, wherein
An accumulator-type fuel injection valve, wherein the volume of the space of the reservoir is 0.3 cm 3 or more.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25201697A JP3904121B2 (en) | 1997-09-17 | 1997-09-17 | Accumulated fuel injection valve |
| DE1998137213 DE19837213B4 (en) | 1997-09-17 | 1998-08-17 | Fuel injection system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25201697A JP3904121B2 (en) | 1997-09-17 | 1997-09-17 | Accumulated fuel injection valve |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1193800A true JPH1193800A (en) | 1999-04-06 |
| JP3904121B2 JP3904121B2 (en) | 2007-04-11 |
Family
ID=17231416
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25201697A Expired - Fee Related JP3904121B2 (en) | 1997-09-17 | 1997-09-17 | Accumulated fuel injection valve |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP3904121B2 (en) |
| DE (1) | DE19837213B4 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007182792A (en) * | 2006-01-05 | 2007-07-19 | Usui Kokusai Sangyo Kaisha Ltd | Common rail fuel injection system |
| JP2013541670A (en) * | 2010-11-02 | 2013-11-14 | ロバート ボッシュ ゲーエムベーハー | Device for injecting fuel into a combustion chamber of an internal combustion engine |
| CN114439662A (en) * | 2022-02-22 | 2022-05-06 | 一汽解放汽车有限公司 | Switching valve and common rail system |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19827267A1 (en) * | 1998-06-18 | 1999-12-23 | Bosch Gmbh Robert | Fuel injection valve for high pressure injection with improved control of the fuel supply |
| JP3991756B2 (en) * | 2002-04-17 | 2007-10-17 | トヨタ自動車株式会社 | Fuel injection device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2529933C2 (en) * | 1975-07-04 | 1984-07-19 | M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8900 Augsburg | Fuel injection device for internal combustion engines |
| JPH07293387A (en) * | 1994-04-21 | 1995-11-07 | Elasis Sistema Ric Fiat Nel Mezzogiorno Soc Consortile Per Azioni | Electromagnetic fuel injection valve |
| US5537972A (en) * | 1994-07-28 | 1996-07-23 | Servojet Electronics Systems | Fuel injection system having a pressure intensifier incorporating an overtravel safety feature |
-
1997
- 1997-09-17 JP JP25201697A patent/JP3904121B2/en not_active Expired - Fee Related
-
1998
- 1998-08-17 DE DE1998137213 patent/DE19837213B4/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007182792A (en) * | 2006-01-05 | 2007-07-19 | Usui Kokusai Sangyo Kaisha Ltd | Common rail fuel injection system |
| JP2013541670A (en) * | 2010-11-02 | 2013-11-14 | ロバート ボッシュ ゲーエムベーハー | Device for injecting fuel into a combustion chamber of an internal combustion engine |
| US9447720B2 (en) | 2010-11-02 | 2016-09-20 | Robert Bosch Gmbh | Device for injecting fuel into the combustion chamber of an internal combustion engine |
| CN114439662A (en) * | 2022-02-22 | 2022-05-06 | 一汽解放汽车有限公司 | Switching valve and common rail system |
Also Published As
| Publication number | Publication date |
|---|---|
| DE19837213B4 (en) | 2004-02-19 |
| DE19837213A1 (en) | 1999-03-18 |
| JP3904121B2 (en) | 2007-04-11 |
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