JPH08296518A - Accumulator fuel injection device - Google Patents

Accumulator fuel injection device

Info

Publication number
JPH08296518A
JPH08296518A JP10396195A JP10396195A JPH08296518A JP H08296518 A JPH08296518 A JP H08296518A JP 10396195 A JP10396195 A JP 10396195A JP 10396195 A JP10396195 A JP 10396195A JP H08296518 A JPH08296518 A JP H08296518A
Authority
JP
Japan
Prior art keywords
pressure
fuel
leak
injection
injection device
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.)
Pending
Application number
JP10396195A
Other languages
Japanese (ja)
Inventor
Susumu Takahashi
進 高橋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Isuzu Motors Ltd
Original Assignee
Isuzu Motors Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Isuzu Motors Ltd filed Critical Isuzu Motors Ltd
Priority to JP10396195A priority Critical patent/JPH08296518A/en
Priority to US08/633,632 priority patent/US5732679A/en
Priority to EP98121205A priority patent/EP0909892A3/en
Priority to DE69605075T priority patent/DE69605075T2/en
Priority to EP96106453A priority patent/EP0740067B1/en
Publication of JPH08296518A publication Critical patent/JPH08296518A/en
Pending legal-status Critical Current

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  • Fuel-Injection Apparatus (AREA)

Abstract

PURPOSE: To provide an accumulator fuel injection device which can prevent breakage due to ultrahigh pressure of supply fuel in advance. CONSTITUTION: In an accumulator fuel injection device which lowers a needle valve by supplying high pressure fuel into a control chamber 19 and leaking fuel in the control chamber 19 into leak flow passages 24, 27 to lift the needle valve, a valve means 31 which raises pressure P2 in the leak flow passages 24, 27 by restricting the downstream side of the leak flow passages 24, 27 and a control means 9 which operates the above valve means 31 so that a difference between pressure P2 in the flow passages and pressure P1 of the high pressure fuel is kept at a predetermined difference in pressure ΔP are provided.

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、特にディーゼル噴射に
用いられる蓄圧式燃料噴射装置に関するものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-accumulation type fuel injection device used especially for diesel injection.

【0002】[0002]

【従来の技術】蓄圧式(コモンレール式)燃料噴射装置
は、インジェクタ内部の制御室に、蓄圧室(コモンレー
ル)から供給される高圧燃料を導入して針弁を下降さ
せ、その制御室内の燃料をリーク流路にリークさせて針
弁をリフトさせるようになっている。
2. Description of the Related Art A pressure-accumulation (common rail) fuel injection system introduces high-pressure fuel supplied from a pressure-accumulation chamber (common rail) into a control chamber inside an injector, lowers a needle valve, and causes the fuel in the control chamber to flow. The needle valve is lifted by leaking into the leak passage.

【0003】図7は従来の蓄圧式燃料噴射装置を示し、
aはインジェクタである。燃料タンクからの燃料は、ポ
ンプbにより昇圧されて蓄圧室cに送られる。蓄圧室c
からはその高圧燃料がインジェクタaに常時供給されて
いる。インジェクタaはコンピュータ内蔵のエンジンコ
ントロールユニット(以下ECUという)dに接続さ
れ、ECUdはインジェクタa内部のソレノイド弁をON
・OFF させる。ソレノイド弁がONとなるとインジェクタ
aが噴射開始となり、このときには高圧燃料がインジェ
クタa内部の制御室からリークされる。このリークされ
た燃料は、リーク流路eを通じて燃料タンクfに戻され
る。
FIG. 7 shows a conventional pressure accumulation type fuel injection device,
a is an injector. The fuel from the fuel tank is boosted by the pump b and sent to the accumulator chamber c. Accumulation chamber c
The high-pressure fuel is constantly supplied to the injector a. The injector a is connected to an engine control unit (hereinafter referred to as ECU) d incorporated in the computer, and the ECU d turns on a solenoid valve inside the injector a.
・ Turn it OFF. When the solenoid valve is turned on, the injector a starts injection, and at this time, high-pressure fuel is leaked from the control chamber inside the injector a. The leaked fuel is returned to the fuel tank f through the leak passage e.

【0004】[0004]

【発明が解決しようとする課題】ところで、インジェク
タa内部の制御室の周辺部には、高圧の供給燃料と低圧
のリーク燃料との流路が比較的狭い部分に近接して形成
されている。このため、噴霧を良好とするために供給燃
料の圧力を超高圧にまで高めようとすると、それら流路
間の圧力差が過大となって応力による破損を招く虞があ
る。
By the way, in the peripheral portion of the control chamber inside the injector a, the flow paths for the high-pressure supply fuel and the low-pressure leak fuel are formed close to a relatively narrow portion. Therefore, if the pressure of the supplied fuel is increased to an ultrahigh pressure in order to improve the atomization, the pressure difference between the flow paths becomes excessive, which may cause damage due to stress.

【0005】そこで、本発明は上記課題を解決すべく創
案されたものであり、その目的は、供給燃料の超高圧化
による破損を未然に防止し得る蓄圧式燃料噴射装置を提
供することにある。
Therefore, the present invention was devised to solve the above-mentioned problems, and an object thereof is to provide a pressure accumulation type fuel injection device capable of preventing damage to the supplied fuel due to super-high pressure. .

【0006】[0006]

【課題を解決するための手段】上記目的を達成するため
本発明は、高圧燃料を制御室に供給して針弁を下降さ
せ、その制御室内の燃料をリーク流路にリークさせて上
記針弁をリフトさせる蓄圧式燃料噴射装置において、上
記リーク流路の下流側を絞ってその流路内圧力を上昇さ
せる弁手段と、上記流路内圧力と上記高圧燃料の圧力と
を所定の圧力差に保持すべく上記弁手段を作動させる制
御手段とを備えたものである。
In order to achieve the above object, the present invention provides a high-pressure fuel to a control chamber to lower a needle valve, causing fuel in the control chamber to leak into a leak flow passage to cause the needle valve to move. In the pressure-accumulation fuel injection device that lifts, the valve means for narrowing the downstream side of the leak flow passage to increase the pressure in the flow passage, and the pressure in the flow passage and the pressure of the high-pressure fuel to a predetermined pressure difference. Control means for actuating the valve means for holding.

【0007】[0007]

【作用】上記構成によれば、リーク流路の流路内圧力が
適当な圧力値まで昇圧され、これにより高圧及び低圧流
路間の圧力差が減小される。
According to the above construction, the pressure inside the flow passage of the leak flow passage is raised to an appropriate pressure value, and thereby the pressure difference between the high pressure and low pressure passages is reduced.

【0008】[0008]

【実施例】以下本発明の好適実施例を添付図面に基づい
て詳述する。
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

【0009】図1は、本発明に係る蓄圧式燃料噴射装置
を示す系統図である。図示するように、ポンプ1は、燃
料タンク2の常圧程度の燃料をフィルタ3を介して吸引
し、それを昇圧し高圧として、配管4を通じて第1蓄圧
室(コモンレール)CR1に送出するようになっている。
第1蓄圧室CR1からは高圧燃料が各供給管5を通じてイ
ンジェクタ6に常時供給されている。インジェクタ6
は、各気筒に設けられ、供給管5からの高圧燃料をその
噴孔より噴射する。第1蓄圧室CR1にはコモンレール圧
センサ7とプレッシャリミッタ8とが設けられ、これら
はコンピュータ内蔵のECU9に電気的に接続される。
ECU9は、コモンレール圧センサ7の検出値に応じて
プレッシャリミッタ8を作動させ、燃料を燃料タンク2
に適宜戻して第1蓄圧室CR1の内圧を所定値に保持す
る。インジェクタ6は、ECU9及びソレノイドドライ
バ10に電気的に接続される。ECU9は、所定の噴射
タイミングでON・OFF 信号をソレノイドドライバ10に
送出し、ソレノイドドライバ10はそのON・OFF 信号を
受けて、インジェクタ6内部のソレノイド弁(図示せ
ず)に作動電力を供給する。ソレノイド弁がONとなる
と、インジェクタ6が噴射開始となり、このときには高
圧燃料がインジェクタ6内部の制御部においてリークさ
れる。
FIG. 1 is a system diagram showing a pressure accumulation type fuel injection device according to the present invention. As shown in the figure, the pump 1 sucks the fuel of about the normal pressure in the fuel tank 2 through the filter 3, raises the pressure of the fuel, and outputs it as high pressure to the first pressure accumulating chamber (common rail) CR1 through the pipe 4. Has become.
High-pressure fuel is constantly supplied from the first pressure accumulating chamber CR1 to the injector 6 through each supply pipe 5. Injector 6
Is provided in each cylinder and injects high-pressure fuel from the supply pipe 5 through its injection hole. A common rail pressure sensor 7 and a pressure limiter 8 are provided in the first pressure accumulating chamber CR1, and these are electrically connected to an ECU 9 incorporated in a computer.
The ECU 9 operates the pressure limiter 8 in accordance with the detection value of the common rail pressure sensor 7 to supply the fuel to the fuel tank 2
The internal pressure of the first pressure accumulating chamber CR1 is maintained at a predetermined value. The injector 6 is electrically connected to the ECU 9 and the solenoid driver 10. The ECU 9 sends ON / OFF signals to the solenoid driver 10 at a predetermined injection timing, and the solenoid driver 10 receives the ON / OFF signal and supplies operating power to a solenoid valve (not shown) inside the injector 6. . When the solenoid valve is turned on, the injector 6 starts injection, and at this time, high-pressure fuel is leaked in the control unit inside the injector 6.

【0010】図2乃至図4はこの制御部の構造を示す縦
断正面図で、図2は無噴射時、図3は噴射時、図4は噴
射終了直後の状態をそれぞれ示している。図示するよう
に、制御部11においては、インジェクタボディ12内
部に所定の燃料流路や中心穴13等が形成され、中心穴
13にはコマンドピストン14が摺動可能に且つ針弁
(図示せず)の上方に同軸に収容される。このコマンド
ピストン14の上昇・下降に合わせて針弁は移動し、コ
マンドピストン14が下降すれば針弁は噴孔を閉じ、上
昇すれば針弁が噴孔を開いて噴射開始となる。
2 to 4 are vertical front views showing the structure of this control unit. FIG. 2 shows the state without injection, FIG. 3 shows the state of injection, and FIG. 4 shows the state immediately after the end of injection. As shown in the figure, in the control unit 11, a predetermined fuel flow path, a central hole 13 and the like are formed inside the injector body 12, and a command piston 14 is slidable in the central hole 13 and a needle valve (not shown). ) Is coaxially housed above. The needle valve moves in accordance with the rise and fall of the command piston 14, and when the command piston 14 descends, the needle valve closes the injection hole, and when it rises, the needle valve opens the injection hole and starts injection.

【0011】中心穴13の上端にはオリフィス部材15
が圧入等により固定されている。オリフィス部材15
は、外周部に形成されたリング状の溝16と、中心部に
形成され下部側が拡径されたオリフィス孔17とを有す
る。溝16とオリフィス孔17とは連通孔18で連通さ
れ、溝16とオリフィス部材15の下部の制御室19と
は連通孔20で連通される。そして溝16には高圧燃料
の供給ポート21が連通されている。制御室19には押
動体22が移動自在に収容され、押動体22とコマンド
ピストン14との間には互いを離反側に付勢するスプリ
ング23が配置される。供給ポート21からは供給管5
からの高圧燃料が常時供給されている。
An orifice member 15 is provided at the upper end of the center hole 13.
Is fixed by press fitting. Orifice member 15
Has a ring-shaped groove 16 formed in the outer peripheral portion, and an orifice hole 17 formed in the central portion and having a lower diameter expanded. The groove 16 and the orifice hole 17 communicate with each other through the communication hole 18, and the groove 16 and the control chamber 19 below the orifice member 15 communicate with each other through the communication hole 20. A high-pressure fuel supply port 21 is communicated with the groove 16. A pusher 22 is movably accommodated in the control chamber 19, and a spring 23 for urging the pusher 22 and the command piston 14 away from each other is arranged between the pusher 22 and the command piston 14. Supply pipe 5 from supply port 21
High-pressure fuel from is always supplied.

【0012】オリフィス部材15の上方には、リーク燃
料の流路となるリーク流路24が形成される。このリー
ク流路24にはオリフィス孔17の上端が開放されてお
り、この開放端は、図示しないソレノイド弁で上昇・下
降される開閉部材25によって開閉がなされる。
Above the orifice member 15, a leak passage 24 is formed which serves as a passage for leak fuel. An upper end of the orifice hole 17 is opened in the leak flow path 24, and the open end is opened and closed by an opening / closing member 25 which is raised and lowered by a solenoid valve (not shown).

【0013】図2に示す無噴射状態のとき、制御室19
内には高圧燃料が充填されてコマンドピストン14を下
方に押圧している。そして図3に示す噴射状態となる
と、開閉部材25が上昇してオリフィス孔17を開く。
こうなると、制御室19内の高圧燃料は押動体22のオ
リフィス中心孔26からオリフィス孔17を通じてリー
ク流路24にリークし、これにより制御室19内が低圧
となってコマンドピストン14がスプリング23の付勢
力に抗じて上昇する。なお針弁には高圧燃料による上向
き或いは開側の力が常時作用しており、この力がコマン
ドピストン14への上昇力となる。さらに図4に示す噴
射終了状態にあっては、開閉部材25が下降してオリフ
ィス孔17を閉じ、このときのオリフィス孔17内の圧
力変化即ち高圧化によって押動体22が僅かに下降す
る。すると、溝16と制御室19とを結ぶ連通孔20は
開放され、溝16の高圧燃料はオリフィス孔17及び連
通孔20を通じて、押動体22を押し下げつつ制御室1
9内に流入する。そしてこの高圧燃料は、押動体22の
側部の隙間等を通じてコマンドピストン14側へと流入
し、その燃圧によってコマンドピストン14を下降させ
る。また押動体22はその上下の圧力バランスによりス
プリング23の付勢力を受けて上昇し、やがてはオリフ
ィス部材15に当接して図2の無噴射状態へと戻る。
In the non-injection state shown in FIG. 2, the control chamber 19
The inside is filled with high-pressure fuel, and the command piston 14 is pressed downward. Then, in the injection state shown in FIG. 3, the opening / closing member 25 rises to open the orifice hole 17.
In this case, the high-pressure fuel in the control chamber 19 leaks from the orifice center hole 26 of the pusher 22 through the orifice hole 17 into the leak flow path 24, whereby the pressure in the control chamber 19 becomes low and the command piston 14 moves to the spring 23. Rise against the bias. It should be noted that an upward force or an opening force due to the high-pressure fuel always acts on the needle valve, and this force serves as an ascending force to the command piston 14. Further, in the injection completion state shown in FIG. 4, the opening / closing member 25 descends to close the orifice hole 17, and the pusher 22 descends slightly due to the pressure change in the orifice hole 17 at this time, that is, the increase in pressure. Then, the communication hole 20 connecting the groove 16 and the control chamber 19 is opened, and the high-pressure fuel in the groove 16 is pushed down the pusher 22 through the orifice hole 17 and the communication hole 20 while controlling the control chamber 1
9 flows into. Then, this high-pressure fuel flows into the command piston 14 side through a gap or the like on the side of the pusher 22, and the command pressure is lowered by the fuel pressure. Further, the pusher 22 receives the urging force of the spring 23 due to the pressure balance between the upper and lower sides thereof and ascends, and eventually contacts the orifice member 15 to return to the non-injection state of FIG.

【0014】図1に戻って、インジェクタ6には、上記
リーク流路24に連通してこれと同様なリーク流路を形
成するリーク管27が接続される。リーク管27は集合
部28において各気筒から集合され、さらにその下流側
には、リーク管27内のリーク燃料の圧力即ちリーク圧
力を所定圧力に制御するためのリーク圧制御手段29が
設けられている。リーク圧制御手段29は、リーク管2
7に設けられてリーク燃料を所定の圧力で貯留する第2
蓄圧室CR2と、第2蓄圧室CR2の出口に設けられてその
出口を絞り、第2蓄圧室CR2からの排出流量を調節する
弁手段たる流量制御弁31とを有する。流量制御弁31
を通過して排出される燃料は燃料タンク2へと戻され
る。流量制御弁31としては、その開度を無段階調節で
きる例えばデューティ制御ソレノイド弁等が採用され
る。
Returning to FIG. 1, the injector 6 is connected to a leak pipe 27 which communicates with the leak flow passage 24 and forms a similar leak flow passage. The leak pipe 27 is gathered from each cylinder in the gathering portion 28, and further on the downstream side thereof, a leak pressure control means 29 for controlling the pressure of the leak fuel in the leak pipe 27, that is, the leak pressure to a predetermined pressure is provided. There is. The leak pressure control means 29 is the leak pipe 2
Second, which is provided in No. 7 and stores leak fuel at a predetermined pressure
It has a pressure accumulating chamber CR2 and a flow rate control valve 31, which is a valve means provided at the outlet of the second pressure accumulating chamber CR2 and restricting the outlet to adjust the discharge flow rate from the second pressure accumulating chamber CR2. Flow control valve 31
The fuel discharged after passing through is returned to the fuel tank 2. As the flow rate control valve 31, for example, a duty control solenoid valve or the like, which can adjust its opening steplessly, is adopted.

【0015】第2蓄圧室CR2には、その内圧即ちリーク
圧力を検知するためのリーク圧センサ32が設けられ、
このリーク圧センサ32と流量制御弁31とはECU9
に電気的に接続される。特にECU9は、第2蓄圧室CR
2のリーク圧センサ32の検出値と、第1蓄圧室CR1の
コモンレール圧センサ7の検出値とを比較して、後述す
る制御フローに従って流量制御弁31を開閉作動させる
制御手段を形成する。
The second pressure accumulator CR2 is provided with a leak pressure sensor 32 for detecting the internal pressure, that is, the leak pressure,
The leak pressure sensor 32 and the flow rate control valve 31 are connected to the ECU 9
Electrically connected to. In particular, the ECU 9 is the second pressure accumulator CR
The detection value of the second leak pressure sensor 32 and the detection value of the common rail pressure sensor 7 of the first pressure accumulating chamber CR1 are compared with each other to form control means for opening and closing the flow control valve 31 according to a control flow described later.

【0016】従来は、インジェクタ6内部でリークした
燃料は燃料タンク2内と等しい常圧程度にまで減圧され
ていた。しかし本実施例では、そのリーク燃料の圧力を
常圧よりも高めることができる。
Conventionally, the fuel leaked inside the injector 6 has been decompressed to a normal pressure equal to that in the fuel tank 2. However, in the present embodiment, the pressure of the leaked fuel can be raised above normal pressure.

【0017】即ち、ECU9で流量制御弁31の開度を
適当に制御することにより、第2蓄圧室CR2からの排出
流量を制限してその内圧を高めておくことができ、これ
によってリーク管27や、インジェクタ6内部のリーク
流路24の流路内圧力も高めた状態にて保持できる。図
2乃至図4を参照して、特にオリフィス部材15には、
リーク圧たる低圧及び高圧の流路がそれぞれ形成される
が、オリフィス部材15が比較的小さい部品でそれら流
路も近接するため、流路を仕切る部分に燃圧差による応
力が生じる。例えば図示例の場合、図3に示すリーク状
態において溝16の下部の環状部33に下方への曲げ力
が生じ易く、特に超高圧を供給する場合には破損に至る
虞がある。しかし本実施例では、リーク圧力を高めて高
圧燃料との圧力差を小さくでき、これによってインジェ
クタ6の破損を未然に防止すると共に、超高圧噴射を実
現することが可能となる。
That is, by appropriately controlling the opening degree of the flow rate control valve 31 by the ECU 9, it is possible to limit the discharge flow rate from the second pressure accumulating chamber CR2 and increase the internal pressure thereof, whereby the leak pipe 27 Alternatively, the pressure inside the flow path of the leak flow path 24 inside the injector 6 can be kept high. With reference to FIGS. 2 to 4, especially in the orifice member 15,
Although low-pressure and high-pressure flow paths, which are leak pressures, are formed, since the orifice member 15 is a relatively small component and these flow paths are close to each other, stress due to the difference in fuel pressure is generated in the part that divides the flow paths. For example, in the case of the illustrated example, a downward bending force is likely to be generated in the annular portion 33 below the groove 16 in the leak state shown in FIG. 3, and there is a possibility of damage especially when an ultrahigh pressure is supplied. However, in the present embodiment, the leak pressure can be increased to reduce the pressure difference with the high-pressure fuel, whereby damage to the injector 6 can be prevented and super-high-pressure injection can be realized.

【0018】図5はECU9の制御フローを示すフロー
チャートで、ECU9は先ずコモンレール圧センサ7の
検出値より第1蓄圧室CR1の圧力P1 を読み込む。そし
て次に第2蓄圧室CR2の圧力指示値P0 を算出するが、
これは具体的には、コモンレール圧センサ7の検出値P
1 から所定の圧力差ΔP、ここでは40MPa を減じること
によって行われる。そして次に、リーク圧センサ32の
検出値より第2蓄圧室CR2の圧力P2 を読み込み、その
圧力値P2 を算出された指示値P0 と比較して、一致す
るならば最初のステップにそのまま戻り、一致しないな
らば一致するように流量制御弁31を開閉作動させる。
これにより、リーク燃料の圧力P2 は供給燃料の圧力P
1 に対し一定の圧力差ΔPに保持されることになる。
FIG. 5 is a flow chart showing a control flow of the ECU 9. The ECU 9 first reads the pressure P 1 of the first pressure accumulating chamber CR1 from the detection value of the common rail pressure sensor 7. Then, the pressure instruction value P 0 of the second pressure accumulating chamber CR2 is calculated,
Specifically, this is the detection value P of the common rail pressure sensor 7.
This is done by subtracting a predetermined pressure difference ΔP, here 40 MPa, from 1 . Then, next, the pressure P 2 of the second pressure accumulating chamber CR2 is read from the detection value of the leak pressure sensor 32, the pressure value P 2 is compared with the calculated instruction value P 0, and if they match, the first step is taken. The flow returns as it is, and if they do not match, the flow control valve 31 is opened and closed so that they match.
As a result, the leak fuel pressure P 2 is equal to the supply fuel pressure P 2.
A constant pressure difference ΔP is maintained for 1 .

【0019】図6は、無噴射時と噴射時とにおける供給
燃料及びリーク燃料の圧力変化を示すグラフで、(a)
が従来、(b)が本実施例の場合である。なお上段は、
ECU9が送出するソレノイド弁のON・OFF 信号であ
る。
FIG. 6 is a graph showing the pressure changes of the supplied fuel and the leaked fuel at the time of no injection and at the time of injection.
Conventionally, (b) is the case of this embodiment. The upper row is
These are ON / OFF signals of the solenoid valve sent by the ECU 9.

【0020】図示するように、(a)の場合、無噴射時
におけるリーク燃料の圧力(リーク圧力)P2 は供給燃
料の圧力(供給圧力)P1 よりも比較的小さい値となっ
ており、これにより噴射時には、供給圧力P1 が比較的
大きい値ΔP1 だけ減小するようになる。これに対し
(b)の場合、無噴射時においてリーク圧力P2 が高い
値となっているため、噴射時の供給圧力P1 の減小は比
較的小さい値ΔP1 に止まる。ここで(b)の場合にお
いて、無噴射時の供給圧力P1 とリーク圧力P2 との差
ΔPが前述の40MPa の圧力差となり、これはインジェク
タ6の針弁の上昇・下降を行わせるのに必要最小限の圧
力差である。なお、この圧力差を小さくすることで針弁
のレスポンス悪化が考えられるが、これはオリフィス孔
17やオリフィス中心孔26の孔径の変更等で対応でき
るし、逆に適度に初期噴射率が抑制されることによって
予混合燃焼時に多く発生するNOxの低減に効果がある
ため問題はない。
As shown in the figure, in the case of (a), the leak fuel pressure (leak pressure) P 2 at the time of no injection is relatively smaller than the supply fuel pressure (supply pressure) P 1 , As a result, during injection, the supply pressure P 1 is reduced by a relatively large value ΔP 1 . On the other hand, in the case of (b), since the leak pressure P 2 has a high value at the time of no injection, the decrease of the supply pressure P 1 at the time of injection stops at a relatively small value ΔP 1 . In the case of (b), the difference ΔP between the supply pressure P 1 and the leak pressure P 2 at the time of no injection becomes the above-mentioned pressure difference of 40 MPa, which causes the needle valve of the injector 6 to rise and fall. It is the minimum necessary pressure difference. Although it is possible that the response of the needle valve deteriorates by reducing this pressure difference, this can be dealt with by changing the hole diameters of the orifice hole 17 and the orifice center hole 26, and conversely, the initial injection rate is appropriately suppressed. Therefore, there is no problem because it is effective in reducing NOx that is often generated during premixed combustion.

【0021】以上による本実施例の他、本発明は種々の
態様にて変形・変更が可能である。
Besides the above-described embodiment, the present invention can be modified and changed in various modes.

【0022】[0022]

【発明の効果】本発明は次の如き優れた効果を発揮す
る。
The present invention exhibits the following excellent effects.

【0023】(1) 供給燃料の超高圧化による破損を
未然に防止できる。
(1) It is possible to prevent damage due to the super-high pressure of the supplied fuel.

【0024】(2) 超高圧噴射を実現できる。(2) Ultra high pressure injection can be realized.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明に係る蓄圧式燃料噴射装置の一実施例を
示す系統図である。
FIG. 1 is a system diagram showing an embodiment of a pressure accumulation type fuel injection device according to the present invention.

【図2】インジェクタの制御部を示し、無噴射時の状態
を示す縦断正面図である。
FIG. 2 is a vertical cross-sectional front view showing a control unit of the injector and showing a state without injection.

【図3】インジェクタの制御部を示し、噴射時の状態を
示す縦断正面図である。
FIG. 3 is a vertical cross-sectional front view showing a control unit of the injector and showing a state during injection.

【図4】インジェクタの制御部を示し、噴射終了直後の
状態を示す縦断正面図である。
FIG. 4 is a vertical sectional front view showing a state immediately after the end of injection, showing the control unit of the injector.

【図5】制御フローを示すフローチャートである。FIG. 5 is a flowchart showing a control flow.

【図6】供給燃料及びリーク燃料の圧力変化を示すグラ
フで、(a)は従来、(b)は本実施例の場合をそれぞ
れ示す。
6A and 6B are graphs showing changes in pressure of supplied fuel and leaked fuel. FIG. 6A shows a conventional case, and FIG. 6B shows a case of the present embodiment.

【図7】従来の蓄圧式燃料噴射装置を示す系統図であ
る。
FIG. 7 is a system diagram showing a conventional pressure accumulation type fuel injection device.

【符号の説明】[Explanation of symbols]

9 エンジンコントロールユニット 19 制御室 24 リーク流路 27 リーク管 31 流量制御弁 P1 供給燃料の圧力 P2 リーク燃料の圧力 ΔP 圧力差9 Engine Control Unit 19 Control Room 24 Leakage Flow Path 27 Leakage Pipe 31 Flow Control Valve P 1 Supply Fuel Pressure P 2 Leakage Fuel Pressure ΔP Pressure Difference

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 高圧燃料を制御室に供給して針弁を下降
させ、該制御室内の燃料をリーク流路にリークさせて上
記針弁をリフトさせる蓄圧式燃料噴射装置において、上
記リーク流路の下流側を絞ってその流路内圧力を上昇さ
せる弁手段と、上記流路内圧力と上記高圧燃料の圧力と
を所定の圧力差に保持すべく上記弁手段を作動させる制
御手段とを備えたことを特徴とする蓄圧式燃料噴射装
置。
1. A pressure-accumulation fuel injection device for supplying high-pressure fuel to a control chamber to lower a needle valve, causing fuel in the control chamber to leak to a leak flow passage, and lifting the needle valve, wherein the leak flow passage is provided. And valve means for increasing the pressure in the flow passage by narrowing the downstream side thereof, and control means for operating the valve means to keep the pressure in the flow passage and the pressure of the high-pressure fuel at a predetermined pressure difference. An accumulator fuel injection device characterized by the above.
JP10396195A 1995-04-27 1995-04-27 Accumulator fuel injection device Pending JPH08296518A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
JP10396195A JPH08296518A (en) 1995-04-27 1995-04-27 Accumulator fuel injection device
US08/633,632 US5732679A (en) 1995-04-27 1996-04-17 Accumulator-type fuel injection system
EP98121205A EP0909892A3 (en) 1995-04-27 1996-04-24 Accumulator-type fuel injection system
DE69605075T DE69605075T2 (en) 1995-04-27 1996-04-24 Fuel injection device of the accumulator type
EP96106453A EP0740067B1 (en) 1995-04-27 1996-04-24 Accumulator-type fuel injection system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10396195A JPH08296518A (en) 1995-04-27 1995-04-27 Accumulator fuel injection device

Publications (1)

Publication Number Publication Date
JPH08296518A true JPH08296518A (en) 1996-11-12

Family

ID=14367989

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10396195A Pending JPH08296518A (en) 1995-04-27 1995-04-27 Accumulator fuel injection device

Country Status (1)

Country Link
JP (1) JPH08296518A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001227431A (en) * 1999-12-09 2001-08-24 Usui Internatl Ind Co Ltd Fuel injection pipe for diesel engine
JP2011169241A (en) * 2010-02-18 2011-09-01 Denso Corp Fuel injection device
JP2014111909A (en) * 2012-12-05 2014-06-19 Nippon Soken Inc Fuel injection valve

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001227431A (en) * 1999-12-09 2001-08-24 Usui Internatl Ind Co Ltd Fuel injection pipe for diesel engine
JP2011169241A (en) * 2010-02-18 2011-09-01 Denso Corp Fuel injection device
JP2014111909A (en) * 2012-12-05 2014-06-19 Nippon Soken Inc Fuel injection valve

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