JPH1018934A - Accumulator fuel injector - Google Patents
Accumulator fuel injectorInfo
- Publication number
- JPH1018934A JPH1018934A JP17476096A JP17476096A JPH1018934A JP H1018934 A JPH1018934 A JP H1018934A JP 17476096 A JP17476096 A JP 17476096A JP 17476096 A JP17476096 A JP 17476096A JP H1018934 A JPH1018934 A JP H1018934A
- Authority
- JP
- Japan
- Prior art keywords
- injection
- fuel
- pressure
- valve
- solenoid valve
- 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
Landscapes
- Fuel-Injection Apparatus (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、一種のサージタン
クである蓄圧配管（以下コモンレールと称する）に高圧
燃料を蓄圧し、この蓄圧された高圧燃料を電磁弁制御式
のインジェクタから噴射するようにした燃料噴射装置に
関し、特に通常の燃料噴射の前あるいは後で少量噴射す
る畜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 method of accumulating high-pressure fuel in an accumulator pipe (hereinafter referred to as a common rail), which is a kind of surge tank, and injecting the accumulated high-pressure fuel from an injector controlled by a solenoid valve. More particularly, the present invention relates to an accumulator type fuel injection device which injects a small amount of fuel before or after normal fuel injection.
【０００２】[0002]
【従来の技術】従来より、インジェクタのニードル弁の
反噴孔側に高圧燃料が導入される圧力制御室を設け、こ
の圧力制御室と低圧側とを電磁弁で断続制御することに
より燃料噴射量を調量するものが知られている。このよ
うな燃料噴射装置では、燃料噴射量は電磁弁の開弁時間
の長短により制御される。電磁弁の弁部材はフルリフト
するとストッパ等に衝突してバウンドするので、通電時
間を増加しても噴射量が単調増加せず、噴射量の調量制
御が不安定になるという問題がある。特開平１−２５３
５６２号公報に示されるものでは、弾性体により弁部材
のバウンドを低減させることにより、通電時間の増加に
伴い噴射量が単調増加する特性を有し、噴射量の調量制
御を安定させようとしている。2. Description of the Related Art Conventionally, a pressure control chamber into which high-pressure fuel is introduced is provided on the side opposite to an injection hole of a needle valve of an injector, and the pressure control chamber and the low-pressure side are intermittently controlled by an electromagnetic valve to control the fuel injection amount. Are known. In such a fuel injection device, the fuel injection amount is controlled by the length of the valve opening time of the solenoid valve. When the valve member of the solenoid valve is fully lifted, it collides with a stopper or the like and bounces. Therefore, even if the energizing time is increased, the injection amount does not monotonically increase, and there is a problem that the injection amount adjustment control becomes unstable. JP-A-1-253
No. 562 discloses a characteristic in which the amount of injection is monotonously increased with an increase in energizing time by reducing the bound of the valve member by an elastic body, and is intended to stabilize the control of the injection amount adjustment. I have.
【０００３】[0003]
【発明が解決しようとする課題】前述したように弾性体
を用いる以外にも通電時間の増加に伴い噴射量を単調増
加させることは可能である。例えば、圧力制御室の容積
を増加させたり、圧力制御室と低圧側との間に設けられ
る絞りの径を小さくしたりすることにより、電磁弁の開
弁による圧力制御室の圧力低下速度を緩和させ、弁部材
のバウンドが減衰してから燃料噴射を行うことができ
る。したがって、通電時間の増加に伴い噴射量が単調増
加するので、噴射量の調量制御が安定する。As described above, it is possible to monotonously increase the injection amount as the energization time increases, in addition to the use of the elastic body as described above. For example, by increasing the volume of the pressure control chamber or reducing the diameter of the throttle provided between the pressure control chamber and the low-pressure side, the pressure reduction rate of the pressure control chamber due to the opening of the solenoid valve is reduced. As a result, fuel injection can be performed after the bounce of the valve member has attenuated. Therefore, the injection amount monotonically increases with an increase in the energization time, and the injection amount adjustment control is stabilized.
【０００４】ここで、ディーゼルエンジンの騒音低減や
排ガス浄化のためにはエンジン気筒内への燃料主噴射の
直前に、微少量の噴射を行うパイロット噴射や燃料主噴
射の後で微少量噴射を行う後噴射が有効である。しか
し、図７に示すように供給燃料圧力が１００MPa を越え
るような高圧時には、噴射量／通電時間の傾きが非常に
大きくなるので、僅かな通電時間の違いにより燃料噴射
量が大きく違ってくる。また、例えば４気筒用エンジン
に適用する場合、図７に示す噴射量特性であれば、図８
に示すように気筒間に特性のズレがあった場合、各気筒
に同量の少量噴射を行おうとすると、気筒毎に通電時間
を変更しなければならないという問題がある。Here, in order to reduce the noise of the diesel engine and purify the exhaust gas, a pilot injection for performing a small amount of injection is performed immediately before the main fuel injection into the engine cylinder, and a minute amount of injection is performed after the main fuel injection. After injection is effective. However, as shown in FIG. 7, at a high pressure where the supply fuel pressure exceeds 100 MPa, the gradient of the injection amount / the energization time becomes very large, so that the fuel injection amount greatly differs due to a slight difference in the energization time. For example, when applied to a four-cylinder engine, if the injection amount characteristic shown in FIG.
As shown in (1), when there is a deviation in the characteristics between the cylinders, there is a problem that the energization time must be changed for each cylinder in order to perform the same small amount injection into each cylinder.
【０００５】本発明はこのような問題を解決するために
なされたものであり、前噴射または後噴射における微少
量噴射制御を容易に行い、かつ気筒間の噴射量調整も容
易に実現できる燃料噴射装置を提供することを目的とす
る。SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a fuel injection system capable of easily performing a small amount injection control in a pre-injection or a post-injection and easily adjusting an injection amount between cylinders. It is intended to provide a device.
【０００６】[0006]
【課題を解決するための手段】本発明の請求項１、２ま
たは３記載の蓄圧式燃料噴射装置によると、電磁弁への
通電時間を増加して弁部材がフルリフトする通電時間に
達したときに、フルリフトにより弁部材をバウンドさせ
て反発力を形成し、この反発力により電磁弁の閉弁速度
を増加させ、弁部材をフルリフトさせないときよりもフ
ルリフトさせるときの電磁弁の開弁時間を短くする。こ
れにより、電磁弁への通電時間の増加に対して噴射量が
略一定もしくは減少する特性期間を形成する。そして、
この特性期間における噴射を前噴射もしくは後噴射とし
ている。したがって、燃料供給圧が高圧であっても通電
時間の変化に伴う噴射量の変化量が僅かであるため、微
少量噴射における燃料の調量制御を容易に行うことがで
きる。また、各気筒間に特性の違いがあっても、噴射量
の差が僅かであるため、気筒毎に電磁弁への通電時間を
変更しなくても前噴射や後噴射において各気筒からほぼ
同量の燃料噴射を行うことができる。According to the pressure accumulating fuel injection device of the present invention, when the energizing time to the solenoid valve is increased and the energizing time for the valve member to reach a full lift is reached. In addition, the valve member is bound by the full lift to form a repulsive force, and the repulsive force increases the closing speed of the solenoid valve, and shortens the valve opening time of the solenoid valve when the valve member is fully lifted than when the valve member is not fully lifted. I do. Thus, a characteristic period is formed in which the injection amount is substantially constant or decreases with an increase in the energization time to the solenoid valve. And
The injection during this characteristic period is defined as pre-injection or post-injection. Therefore, even when the fuel supply pressure is high, the amount of change in the injection amount due to the change in the energization time is small, so that it is possible to easily perform the fuel adjustment control in the minute amount injection. Also, even if there is a difference in characteristics between the cylinders, the difference in the injection amount is small, so that the pre-injection and post-injection do not change from each cylinder without changing the energization time to the solenoid valve for each cylinder. A quantity of fuel injection can be made.
【０００７】[0007]
【発明の実施の形態】以下、本発明の実施の形態を示す
実施例について説明する。本発明の蓄圧式燃料噴射装置
の一実施例を図１および図２を用いて説明する。図１に
示すインジェクタ１には、図示しないコモンレールで蓄
圧された一定圧の高圧燃料が図示しない燃料配管を介し
て燃料フィルタ６０を通って供給されている。Embodiments of the present invention will be described below. One embodiment of the pressure accumulating fuel injection device of the present invention will be described with reference to FIGS. The injector 1 shown in FIG. 1 is supplied with high-pressure fuel of a constant pressure stored in a common rail (not shown) through a fuel filter 60 via a fuel pipe (not shown).
【０００８】インジェクタ１の噴孔側に設けられた噴射
ノズル１０のノズルボディ１１には、噴孔１１ａを開閉
するニードル弁２０が往復移動可能に収容されている。
ノズルボディ１１およびインジェクタボディ１３はパッ
キンチップ１２を挟んでリテーニングナット１４で結合
されている。ニードル弁２０の反噴孔側にはプレッシャ
ピン２１が配設されており、プレッシャピン２１の反噴
孔側にはプレッシャピン２１に接触あるいは連結する制
御ピストン２２が配設されている。プレッシャピン２１
はスプリング２３内に貫挿されており、スプリング２３
はプレッシャピン２１を図１の下方、つまり噴孔閉塞方
向に付勢している。制御ピストン２２の反噴孔側には圧
力制御室６１が設けられている。[0008] A needle valve 20 for opening and closing the injection hole 11a is accommodated in the nozzle body 11 of the injection nozzle 10 provided on the injection hole side of the injector 1 so as to be able to reciprocate.
The nozzle body 11 and the injector body 13 are connected by a retaining nut 14 with the packing tip 12 interposed therebetween. A pressure pin 21 is disposed on the side opposite to the injection hole of the needle valve 20, and a control piston 22 that is in contact with or is connected to the pressure pin 21 is disposed on the side opposite to the injection hole of the pressure pin 21. Pressure pin 21
Is inserted through the spring 23 and the spring 23
Urges the pressure pin 21 downward in FIG. 1, that is, in the injection hole closing direction. A pressure control chamber 61 is provided on the side opposite to the injection hole of the control piston 22.
【０００９】燃料フィルタ６０から導入された高圧燃料
は、高圧燃料通路６２と高圧燃料通路６３に分岐する。
高圧燃料通路６２に分岐した高圧燃料はニードル弁２０
の周囲に環状に形成された燃料溜まり２４に供給され、
高圧燃料通路６２に分岐した高圧燃料は圧力制御室６１
に供給されている。燃料溜まり２４内の高圧燃料の圧力
は図１の上方、つまり燃料溜まり２４と噴孔１１ａとが
連通するリフト方向にニードル弁２０を付勢し、圧力制
御室６１内の高圧燃料の圧力は図１の下方に制御ピスト
ン２２を付勢する。高圧燃料通路６３と圧力制御室６１
とは高圧燃料通路６３から圧力制御室６１への流入燃料
量を規制する第１の絞り部としての第１の絞り孔６５で
連通されている。平板プレート５３には平板プレート５
３を軸方向に貫通し第１の絞り孔６５よりも通路抵抗の
小さい連通路としての第２の絞り部としての第２の絞り
孔６６が形成されている。The high-pressure fuel introduced from the fuel filter 60 branches into a high-pressure fuel passage 62 and a high-pressure fuel passage 63.
The high-pressure fuel branched to the high-pressure fuel passage 62 is supplied to the needle valve 20.
Is supplied to a fuel reservoir 24 formed in an annular shape around
The high-pressure fuel branched to the high-pressure fuel passage 62 is supplied to the pressure control chamber 61.
Is supplied to The pressure of the high-pressure fuel in the fuel reservoir 24 urges the needle valve 20 in the upward direction of FIG. 1, that is, the lift direction in which the fuel reservoir 24 and the injection hole 11a communicate with each other. 1, the control piston 22 is urged downward. High-pressure fuel passage 63 and pressure control chamber 61
Is communicated with a first throttle hole 65 as a first throttle portion for regulating the amount of fuel flowing into the pressure control chamber 61 from the high-pressure fuel passage 63. The flat plate 53 has a flat plate 5
3, a second throttle hole 66 is formed as a second throttle portion as a communication passage having a smaller passage resistance than the first throttle hole 65.
【００１０】低圧燃料通路６４は制御ピストン２２およ
びニードル弁２０の摺動クリアランスからのリーク燃料
を回収するための燃料通路であり、低圧燃料室６７に連
通している。電磁弁３０は、圧力制御室６１と低圧燃料
室６７とを断続する電磁二方弁であり、リーテーニング
ナット５１とインジェクタボディ１３との間に配設され
ている。電磁コイル３２はコア３１内に巻装されてお
り、コネクタ３３から電力が供給される。弁部材４０は
シャフト４１、支持部材４２、球状部材４３およびプッ
シュロッド４４からなり、シャフト４１の電磁コイル３
２側にはアーマチャ３４が固定されている。The low-pressure fuel passage 64 is a fuel passage for collecting leaked fuel from the sliding clearance between the control piston 22 and the needle valve 20, and communicates with the low-pressure fuel chamber 67. The solenoid valve 30 is an electromagnetic two-way valve that connects and disconnects the pressure control chamber 61 and the low-pressure fuel chamber 67, and is disposed between the retaining nut 51 and the injector body 13. The electromagnetic coil 32 is wound around the core 31, and power is supplied from the connector 33. The valve member 40 includes a shaft 41, a support member 42, a spherical member 43, and a push rod 44.
An armature 34 is fixed to the two sides.
【００１１】図２に示すように、シャフト４１の先端部
には円筒状に形成された支持部材４２が圧入等で固定さ
れている。支持部材４２と球状部材４３との間には数μ
ｍのクリアランスが形成されており、球状部材４３はシ
ャフト４１の先端に形成された円錐状凹面４１ａと支持
部材４２の内壁によりシャフト４１に対し回動自在に組
み付けられている。支持部材４２の先端部をかしめるこ
とにより球状部材４３はシャフト４１からの脱落を防止
されている。球状部材４３は鋼球の一部を後加工で切断
したものであるが、本発明では、切削により成形するこ
とも可能である。As shown in FIG. 2, a cylindrical support member 42 is fixed to the tip of the shaft 41 by press-fitting or the like. Several μm is provided between the support member 42 and the spherical member 43.
The spherical member 43 is rotatably attached to the shaft 41 by a conical concave surface 41 a formed at the tip of the shaft 41 and the inner wall of the support member 42. By caulking the tip of the support member 42, the spherical member 43 is prevented from falling off the shaft 41. Although the spherical member 43 is obtained by cutting a part of a steel ball by post-processing, in the present invention, it can be formed by cutting.
【００１２】電磁コイル３２への通電オフ時、スプリン
グ４５の付勢力によりプッシュロッド４４が図１の下方
に押下され、球状部材４３が平板プレート５３に着座す
る。図２に示す球状部材４３の端面４３ａが平板プレー
ト５３の端面５３ａに当接することにより、圧力制御室
６１と低圧燃料室６７との連通が遮断される。電磁コイ
ル３２への通電オン時、電磁コイル３２に発生する磁力
によりアーマチャ３４が電磁コイル３２に吸引されシャ
フト４１が図１の上方にリフトすることにより球状部材
４３が平板プレート５３から離座する。シャフト４１お
よび球状部材４３からなる弁部材４０が平板プレート５
３から離座すると、第２の絞り孔６６と低圧燃料室６７
とが連通し、第２の絞り孔６６、低圧燃料室６７、低圧
燃料通路６８、封止部材５２に形成された燃料回収通路
５２ａを経て圧力制御室６１内の高圧燃料がインジェク
タ１から排出される。スペーサ５４の軸長を変更するこ
とにより弁部材４０のリフト量を調整できる。When the power supply to the electromagnetic coil 32 is turned off, the push rod 44 is pressed downward in FIG. 1 by the urging force of the spring 45, and the spherical member 43 is seated on the flat plate 53. When the end face 43a of the spherical member 43 shown in FIG. 2 abuts on the end face 53a of the flat plate 53, the communication between the pressure control chamber 61 and the low-pressure fuel chamber 67 is shut off. When energization of the electromagnetic coil 32 is turned on, the armature 34 is attracted to the electromagnetic coil 32 by the magnetic force generated in the electromagnetic coil 32 and the shaft 41 is lifted upward in FIG. The valve member 40 composed of the shaft 41 and the spherical member 43 is
3, the second throttle hole 66 and the low-pressure fuel chamber 67
The high-pressure fuel in the pressure control chamber 61 is discharged from the injector 1 through the second throttle hole 66, the low-pressure fuel chamber 67, the low-pressure fuel passage 68, and the fuel recovery passage 52a formed in the sealing member 52. You. By changing the axial length of the spacer 54, the lift amount of the valve member 40 can be adjusted.
【００１３】本実施例における各寸法の具体例を次に示
す。球状部材４３の端面４３ａの径Ｄ1 を１．４３mm、
第１の絞り孔６５の径をφ０．２mm、第２の絞り孔６６
の径Ｄ2 をφ０．３２mm、圧力制御室６１の容積を７０
mm3 、弁部材４０のリフト量を０．１２mm、スプリング
４４のセット荷重を６５Ｎ、スプリング２３のセット荷
重を４０Ｎ、制御ピストン２２の径をφ５mm、ニードル
弁２０の最外径をφ４．０mm、ニードル弁２０のシート
径をφ２．２５mmとしている。これにより、制御ピスト
ン２２の受圧面積は噴孔閉塞時のニードル弁２０の受圧
面積よりも約１１mm2 大きくなっている。A specific example of each dimension in this embodiment is shown below. The diameter D 1 of the end face 43a of the spherical member 43 1.43 mm,
The diameter of the first throttle hole 65 is φ0.2 mm, and the diameter of the second throttle hole 66 is
Diameter D 2 is φ0.32 mm and the volume of the pressure control chamber 61 is 70
mm 3 , the lift amount of the valve member 40 is 0.12 mm, the set load of the spring 44 is 65 N, the set load of the spring 23 is 40 N, the diameter of the control piston 22 is φ5 mm, the outermost diameter of the needle valve 20 is φ4.0 mm, The seat diameter of the needle valve 20 is 2.25 mm. As a result, the pressure receiving area of the control piston 22 is about 11 mm 2 larger than the pressure receiving area of the needle valve 20 when the injection hole is closed.
【００１４】本実施例は、図３に示すように前噴射とし
てのパイロット噴射を行ってから主噴射を行っている。
次に、前噴射におけるインジェクタ１の作動を説明す
る。 (1) 電磁コイル３２への通電オフ時、スプリング２３の
付勢力と圧力制御室６１の燃料圧力から制御ピストン２
２が受ける力との和からニードル弁２０が噴孔閉塞方向
に受ける力は、燃料溜まり２４の燃料からニードル弁２
０がリフト方向に受ける力よりも大きい。したがって、
ニードル弁２０は噴孔１１ａを閉塞し、燃料噴射は行わ
れない。これは、前述したように制御ピストン２２の受
圧面積とニードル弁２０の受圧面積とに差があり、前者
の方が大きいためであり、さらに、スプリング２３の付
勢力はニードル弁２０が噴孔１１ａを閉塞する方向であ
るためである。In this embodiment, as shown in FIG. 3, the main injection is performed after the pilot injection is performed as the pre-injection.
Next, the operation of the injector 1 in the pre-injection will be described. (1) When the power to the electromagnetic coil 32 is turned off, the control piston 2 is determined based on the urging force of the spring 23 and the fuel pressure in the pressure control chamber 61.
The force received by the needle valve 20 in the injection hole closing direction from the sum of the force received by the needle valve 2 and the needle valve 2
0 is greater than the force received in the lift direction. Therefore,
The needle valve 20 closes the injection hole 11a, and no fuel injection is performed. This is because there is a difference between the pressure receiving area of the control piston 22 and the pressure receiving area of the needle valve 20 as described above, and the former is larger. Further, the urging force of the spring 23 is such that the needle valve 20 has the injection hole 11a. This is because the direction is to close.
【００１５】(2) 電磁コイル３２への通電をオンする
と、電磁コイル３２に発生する磁力によりアーマチャ３
４および弁部材４０が図１の上方に吸引される。この弁
部材４０のリフトにより球状部材４３が平板プレート５
３から離座すると、圧力制御室６１は第２の絞り孔６６
を介して低圧燃料室６７と連通する。したがって、圧力
制御室６１の燃料圧力が低下する。しかし、前噴射のよ
うな微少量噴射の場合、電磁コイル３２への通電オン中
は、ニードル弁２０がリフトする程度に圧力制御室６１
の圧力が低下しない。(2) When energization of the electromagnetic coil 32 is turned on, the armature 3
4 and the valve member 40 are sucked upward in FIG. The lift of the valve member 40 causes the spherical member 43 to move the flat plate 5
3, the pressure control chamber 61 becomes the second throttle hole 66.
Communicates with the low-pressure fuel chamber 67 via the Therefore, the fuel pressure in the pressure control chamber 61 decreases. However, in the case of the minute injection such as the pre-injection, while the power supply to the electromagnetic coil 32 is on, the pressure control chamber 61 is moved to the extent that the needle valve 20 is lifted.
Pressure does not drop.
【００１６】(3) 再び電磁コイル３２への通電をオフす
ると、スプリング４５の付勢力により弁部材４０が押下
されるため、球状部材４３は開弁方向にオーバシュート
した後平板プレート５３に着座する方向に動きだす。電
磁コイル３２への通電がオフされて以降も、二方弁のリ
フト量がある程度以下になるまでは、圧力制御室６１の
圧力が低下し続け、圧力制御室６１の燃料圧力から制御
ピストン２２が受ける力とスプリング２３の付勢力との
和からニードル弁２０が噴孔閉塞方向に受ける力が、燃
料溜まり２４の燃料圧力からニードル弁２０がリフト方
向に受ける力よりも小さくなり、ニードル弁２０がリフ
トし、噴孔１１ａから燃料が噴射される。(3) When the power supply to the electromagnetic coil 32 is turned off again, the valve member 40 is pressed down by the urging force of the spring 45, so that the spherical member 43 overshoots in the valve opening direction and then sits on the flat plate 53. Start moving in the direction. Even after the energization of the electromagnetic coil 32 is turned off, the pressure in the pressure control chamber 61 continues to decrease until the lift amount of the two-way valve becomes a certain amount or less. From the sum of the received force and the urging force of the spring 23, the force that the needle valve 20 receives in the injection hole closing direction becomes smaller than the force that the needle valve 20 receives in the lift direction from the fuel pressure of the fuel reservoir 24, and the needle valve 20 The fuel is lifted, and fuel is injected from the injection hole 11a.
【００１７】球状部材４３と平板プレート５３との距
離、つまり二方弁のリフト量がある程度以下になり、圧
力制御室６１と低圧燃料室６７との通路抵抗が大きくな
ると、圧力制御室６１の燃料圧力が上昇する。圧力制御
室６１の圧力が上昇し、圧力制御室６１の燃料圧力から
制御ピストン２２が受ける力とスプリング２３の付勢力
との和からニードル弁２０が噴孔閉塞方向に受ける力
が、燃料溜まり２４の燃料圧力からニードル弁２０が開
弁方向に受ける力よりも大きくなると、ニードル弁２０
が下降し、噴孔１１ａが閉塞され、燃料噴射が終了す
る。ただし、このとき、ニードル弁２０が燃料溜まり２
４から受ける受圧面積は、噴孔閉塞時とは異なり、φ
４．０mmの円となっている。When the distance between the spherical member 43 and the flat plate 53, that is, the lift amount of the two-way valve becomes smaller than a certain level, and the passage resistance between the pressure control chamber 61 and the low-pressure fuel chamber 67 increases, the fuel in the pressure control chamber 61 Pressure rises. The pressure in the pressure control chamber 61 rises, and the force received by the needle valve 20 in the injection hole closing direction from the sum of the force received by the control piston 22 and the urging force of the spring 23 from the fuel pressure in the pressure control chamber 61 becomes the fuel pool 24. When the force applied to the needle valve 20 in the valve opening direction becomes larger from the fuel pressure of the needle valve 20, the needle valve 20
Is lowered, the injection hole 11a is closed, and the fuel injection ends. However, at this time, the needle valve 20 is
4 is different from the pressure receiving area when the injection hole is closed.
It is a circle of 4.0 mm.
【００１８】本実施例では、前述したような数値により
インジェクタ１を形成したことにより、０．４ms近辺の
極短い時間通電をオンしても、制御圧力室６１の燃料圧
力が低下してニードル弁２０がリフトし、噴孔１１ａか
ら燃料が噴射される。図４に示すように、通電時間が
０．３２msではフルリフトしてストッパ等に衝突する前
に弁部材４０は下降を開始する。どちらの通電オン時間
においても、電磁コイル３２への通電は燃料噴射開始前
にオフされ、弁部材４０がフルリフトしなくても燃料が
噴射される。通電オン時間を徐々に長くして弁部材４０
のフルリフト直後に通電をオフすると、弁部材４０がス
トッパ等に衝突してバウンドし、電磁弁３０の開弁時間
が短くなる現象が生ずる。この現象により、図５の実測
データに示すように、噴射量／通電時間の関係は単調増
加ではなくなり、通電時間を増加しても、噴射量が減少
するという特性となる。In this embodiment, since the injector 1 is formed with the above-mentioned numerical values, the fuel pressure in the control pressure chamber 61 decreases even if the energization is turned on for a very short time around 0.4 ms, and the needle valve 20 is lifted, and fuel is injected from the injection hole 11a. As shown in FIG. 4, when the energization time is 0.32 ms, the valve member 40 starts to descend before full-lift and collision with a stopper or the like. In any of the energization ON times, the energization of the electromagnetic coil 32 is turned off before the start of fuel injection, and fuel is injected even if the valve member 40 does not fully lift. The energization ON time is gradually increased, and the valve member 40
If the power is turned off immediately after the full lift, the valve member 40 collides with a stopper or the like and bounces, causing a phenomenon that the opening time of the solenoid valve 30 is shortened. Due to this phenomenon, as shown in the actual measurement data in FIG. 5, the relationship between the injection amount and the energization time does not increase monotonously, and the injection amount decreases even if the energization time increases.
【００１９】次に、比較例と比較することにより本実施
例の効果を説明する。比較例では、インジェクタの各寸
法を次のように設定している。第１の絞り孔６５の径を
φ０．２mm、第２の絞り孔６６の径をφ０．３０mm、圧
力制御室６１の容積を１００mm3 、弁部材４０のリフト
量を０．１２mm、スプリング４４のセット荷重を６５
Ｎ、スプリング２３によるニードル弁２０のセット荷重
を４０Ｎ、制御ピストン２２の径をφ５mm、ニードル弁
２０の最外径をφ４．０mm、ニードル弁２０のシート径
をφ２．２５mmとする。つまり、比較例は本実施例に比
べ、第２の絞り孔６６の径が小さくなって通路抵抗が大
きくなるとともに圧力制御室６１の容積が増加している
ので、電磁コイル３２への通電をオンしても本実施例に
比較して圧力制御室６１の圧力の低下速度が遅くなり、
ニードル弁２０のリフト時期が遅れる。したがって、弁
部材４０がバウンドする時間領域では噴孔１１ａから噴
射せずバウンドが減衰してから噴射が開始されるので、
従来技術で述べたように、図７に示すように通電時間が
増加するにしたがって燃料噴射量が単調増加する特性に
なる。このような特性は、燃料供給圧が低い場合には燃
料噴射量の調整を制御しやすいという利点がある反面、
燃料供給圧が高く、かつパイロット噴射時のように微少
噴射量を制御しなければならない場合、噴射量／通電時
間の傾きが大きくなるので、却って燃料噴射量の調整が
困難になる。また、図８に示すように各気筒インジェク
タの経年変化等により各気筒間に噴射量／通電時間の特
性変化がある場合には、通電時間を同じにすると燃料噴
射量がばらつくので、特性に応じて通電時間を調整しな
ければならず、制御が複雑になってしまう。Next, the effect of this embodiment will be described by comparing with a comparative example. In the comparative example, each dimension of the injector is set as follows. The diameter of the first throttle hole 65 is φ0.2 mm, the diameter of the second throttle hole 66 is φ0.30 mm, the volume of the pressure control chamber 61 is 100 mm 3 , the lift amount of the valve member 40 is 0.12 mm, Set load to 65
N, the set load of the needle valve 20 by the spring 23 is 40N, the diameter of the control piston 22 is 5 mm, the outermost diameter of the needle valve 20 is 4.0 mm, and the seat diameter of the needle valve 20 is 2.25 mm. That is, in the comparative example, since the diameter of the second throttle hole 66 is reduced and the passage resistance is increased and the volume of the pressure control chamber 61 is increased, the power supply to the electromagnetic coil 32 is turned on. Even in this case, the rate of decrease in the pressure of the pressure control chamber 61 is lower than in this embodiment,
The lift timing of the needle valve 20 is delayed. Therefore, in the time region in which the valve member 40 bounces, the injection is started after the bounce is attenuated without being injected from the injection hole 11a.
As described in the related art, as shown in FIG. 7, the characteristic is such that the fuel injection amount monotonously increases as the energization time increases. Such a characteristic has an advantage that it is easy to control the adjustment of the fuel injection amount when the fuel supply pressure is low,
When the fuel supply pressure is high and the minute injection amount has to be controlled as in the case of pilot injection, the gradient of the injection amount / energization time becomes large, so that it becomes rather difficult to adjust the fuel injection amount. Further, as shown in FIG. 8, when there is a characteristic change of the injection amount / energization time between the cylinders due to the aging of the cylinder injectors or the like, the fuel injection amount varies when the energization time is the same. It is necessary to adjust the energization time, and the control becomes complicated.
【００２０】このような比較例に比べ本実施例では、パ
イロット噴射時のように電磁コイル３２への通電オン時
間が極短く弁部材４０がフルリフトしないときにも噴孔
１１ａからの燃料噴射を可能にしている。そして、弁部
材４０がフルリフトしたときのバウンドを利用し、電磁
コイル３２への通電オン時間が増加しても燃料噴射量が
逆に減少する、あるいは殆ど変化しないという特性を有
している。したがって、パイロット噴射時のように通電
オン時間が極短い範囲内において、燃料供給圧が例えば
１００MPa を超えるような高圧であっても、噴射量／通
電時間の変化量が小さいので微少燃料の噴射量を制御し
やすい。本実施例では、通電オン時間が０．４ms近辺の
微少噴射領域の噴射量はパイロット噴射で要求される
２．０mm3／stに設定されている。この領域では、通電
時間に対する噴射量変化はほとんどなく非常に安定して
微少量噴射を行うことができる。また、例えば４気筒用
エンジンに適用する場合、図５に示す噴射量特性であれ
ば、図６に示すように気筒間の特性のずれがあった場合
でも、高精度を要求される微少量噴射を各気筒に通電時
間を変更することなく同一の通電時間で実現することが
できる。Compared to the comparative example, in the present embodiment, the fuel injection from the injection hole 11a can be performed even when the energization ON time to the electromagnetic coil 32 is extremely short, such as during pilot injection, and the valve member 40 does not fully lift. I have to. Then, by utilizing the bound when the valve member 40 is fully lifted, the fuel injection amount has a characteristic that the fuel injection amount decreases or hardly changes even if the energization ON time to the electromagnetic coil 32 increases. Therefore, in the range where the power-on time is extremely short as in the case of pilot injection, even if the fuel supply pressure is as high as over 100 MPa, for example, the change in the injection amount / power-on time is small, so the injection amount of the minute fuel is small. Easy to control. In this embodiment, the injection amount in the minute injection region where the power-on time is around 0.4 ms is set to 2.0 mm 3 / st required for pilot injection. In this region, there is almost no change in the injection amount with respect to the energization time, and very small injection can be performed very stably. In addition, for example, when applied to a four-cylinder engine, if the injection amount characteristics are as shown in FIG. 5, even if there is a deviation in characteristics between the cylinders as shown in FIG. Can be realized with the same energizing time without changing the energizing time for each cylinder.
【００２１】以上説明した本実施例では、前噴射として
のパイロット噴射について説明したが、微少量噴射にお
ける本実施例の噴射特性は後噴射においても同じであ
る。In the above-described embodiment, the pilot injection as the pre-injection has been described. However, the injection characteristics of the embodiment in the case of minute injection are the same in the post-injection.
【図１】本発明の一実施例によるインジェクタを示す断
面図である。FIG. 1 is a cross-sectional view illustrating an injector according to an embodiment of the present invention.
【図２】本実施例の電磁弁の弁部材先端の構造を示す斜
視図である。FIG. 2 is a perspective view showing a structure of a distal end of a valve member of the solenoid valve according to the embodiment.
【図３】本実施例のパイロット噴射および主噴射を示す
特性図である。FIG. 3 is a characteristic diagram illustrating pilot injection and main injection according to the present embodiment.
【図４】本実施例の電磁コイルへ通電パルスと弁部材の
リフト量の関係を示す特性図である。FIG. 4 is a characteristic diagram illustrating a relationship between an energizing pulse to the electromagnetic coil and a lift amount of a valve member according to the present embodiment.
【図５】本実施例の電磁コイルへの通電時間と噴射量と
の関係を示す特性図である。FIG. 5 is a characteristic diagram illustrating a relationship between a current supply time to the electromagnetic coil and an injection amount according to the present embodiment.
【図６】本実施例の各気筒毎における電磁コイルへの通
電時間と噴射量との関係を示す特性図である。FIG. 6 is a characteristic diagram showing a relationship between a current supply time to an electromagnetic coil and an injection amount for each cylinder of the present embodiment.
【図７】比較例の電磁コイルへの通電時間と噴射量との
関係を示す特性図である。FIG. 7 is a characteristic diagram showing a relationship between a current supply time to an electromagnetic coil and an injection amount according to a comparative example.
【図８】比較例の各気筒毎における電磁コイルへの通電
時間と噴射量との関係を示す特性図である。FIG. 8 is a characteristic diagram illustrating a relationship between a current supply time to an electromagnetic coil and an injection amount for each cylinder of a comparative example.
１０ インジェクタ １１ａ 噴孔 ２０ ニードル弁 ２２ 制御ピストン ３０ 電磁弁 ６１ 圧力制御室 ６２ 高圧燃料通路 ６５ 第１の絞り孔 ６６ 第２の絞り孔 ６７ 低圧燃料室 ６８ 低圧燃料通路 DESCRIPTION OF SYMBOLS 10 Injector 11a Injection hole 20 Needle valve 22 Control piston 30 Solenoid valve 61 Pressure control room 62 High pressure fuel passage 65 First throttle hole 66 Second throttle hole 67 Low pressure fuel chamber 68 Low pressure fuel passage
───────────────────────────────────────────────────── フロントページの続き (72)発明者 黒柳 正利 愛知県刈谷市昭和町１丁目１番地 日本電 装株式会社内 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masatoshi Kuroyagi 1-1-1, Showa-cho, Kariya-shi, Aichi, Japan
Claims (3)
ゼル内燃機関の各気筒毎に設けられたインジェクタに供
給し、このインジェクタの噴射ノズルから各気筒に燃料
を噴射し、主噴射に対して前噴射および後噴射の少なく
ともいずれかを行う蓄圧式燃料噴射装置であって、 前記噴射ノズルの噴孔に高圧燃料を供給可能な高圧燃料
通路と前記噴孔とを断続するニードル弁と、 前記ニードル弁の反噴孔側に前記ニードル弁とともに往
復移動可能に設けられた制御ピストンと、 前記制御ピストンの反噴孔側に設けられ前記高圧燃料通
路から供給される燃料圧力により前記制御ピストンを前
記噴孔閉塞方向に付勢する圧力制御室と低圧燃料通路ま
たは低圧燃料室とを断続することにより、前記噴孔から
の燃料噴射量を制御する電磁弁とを備え、 前記高圧燃料通路と前記圧力制御室との間に前記圧力制
御室への導入燃料量を制限する第１の絞り部を設け、前
記圧力制御室と前記低圧燃料通路または前記低圧燃料室
との間に前記第１の絞り部より通路抵抗の小さい第２の
絞り部を設け、 前記電磁弁は、前記電磁弁への通電をオンすることによ
り発生する磁力により吸引されてリフトし前記圧力制御
室と前記低圧燃料通路または前記低圧燃料室とを連通す
る弁部材を有し、 前記電磁弁への通電時間が短く前記弁部材がフルリフト
しない場合にも燃料噴射が行われ、前記電磁弁への通電
時間を増加して前記弁部材がフルリフトする通電時間に
達したときにフルリフトにより前記弁部材をバウンドさ
せて反発力を形成し、この反発力により前記電磁弁の閉
弁速度を増加させ、前記弁部材をバウンドさせないとき
よりもバウンドさせるときの前記電磁弁の開弁時間を短
くすることで、前記電磁弁への通電時間の増加に対し噴
射量が略一定もしくは減少する特性期間を形成し、この
特性期間における噴射を前記前噴射もしくは前記後噴射
とすることを特徴とする蓄圧式燃料噴射装置。1. A high-pressure fuel stored in a pressure storage pipe is supplied to an injector provided for each cylinder of a diesel internal combustion engine, and fuel is injected into each cylinder from an injection nozzle of the injector. A pressure-accumulation fuel injection device that performs at least one of injection and post-injection, a needle valve intermittently connecting a high-pressure fuel passage capable of supplying high-pressure fuel to an injection hole of the injection nozzle and the injection hole, and the needle valve. A control piston provided reciprocally with the needle valve on a side opposite to the injection hole, and a fuel pressure provided from the high-pressure fuel passage provided on the side opposite to the injection hole of the control piston. A solenoid valve for controlling a fuel injection amount from the injection hole by intermittently intermitting a pressure control chamber for urging in a closing direction and a low-pressure fuel passage or a low-pressure fuel chamber; A first throttle section is provided between the high-pressure fuel passage and the pressure control chamber to limit the amount of fuel introduced into the pressure control chamber, and between the pressure control chamber and the low-pressure fuel passage or the low-pressure fuel chamber. A second throttle portion having a passage resistance smaller than that of the first throttle portion, wherein the solenoid valve is attracted and lifted by a magnetic force generated by turning on energization of the solenoid valve, lifts up the pressure control chamber, and A valve member that communicates with the low-pressure fuel passage or the low-pressure fuel chamber; fuel injection is performed even when the energizing time to the electromagnetic valve is short and the valve member is not fully lifted; and the energizing time to the electromagnetic valve is reduced. When the energizing time for the valve member to be fully lifted reaches the full time, the valve member is bound by the full lift to form a repulsive force, and the repulsive force increases the valve closing speed of the solenoid valve, thereby increasing the valve member. bound By shortening the opening time of the solenoid valve when the bounce is performed than when the bounce is not performed, a characteristic period in which the injection amount is substantially constant or decreases with an increase in the energization time to the solenoid valve is formed. Wherein the injection in the fuel injection system is the pre-injection or the post-injection.
噴射量が減少するとともにその減少量が徐々に少なくな
る減少期間と、この減少期間に連続しており、前記電磁
弁への通電時間の増加に対して噴射量が増加するととも
にその増加量が徐々に大きくなる増加期間とを有し、 前記特性期間は、前記減少期間と前記増加期間とのうち
の特定の期間であることを特徴とする請求項１記載の蓄
圧式燃料噴射装置。2. A decrease period in which the injection amount decreases with an increase in the energization time to the solenoid valve and the decrease amount gradually decreases, and a decrease period is continuous with the decrease period, and the energization of the solenoid valve is performed. It has an increasing period in which the injection amount increases with an increase in time and the increasing amount gradually increases, and the characteristic period is a specific period of the decreasing period and the increasing period. The pressure accumulating fuel injection device according to claim 1, wherein
弁への通電オフタイミングは燃料噴射よりも前であるこ
とを特徴とする請求項１または２記載の蓄圧式燃料噴射
装置。3. The accumulator type fuel injection device according to claim 1, wherein in the case of the pre-injection or the post-injection, the power-off timing of the solenoid valve is before the fuel injection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17476096A JP3738921B2 (en) | 1996-07-04 | 1996-07-04 | Accumulated fuel injection system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17476096A JP3738921B2 (en) | 1996-07-04 | 1996-07-04 | Accumulated fuel injection system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1018934A true JPH1018934A (en) | 1998-01-20 |
| JP3738921B2 JP3738921B2 (en) | 2006-01-25 |
Family
ID=15984201
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17476096A Expired - Lifetime JP3738921B2 (en) | 1996-07-04 | 1996-07-04 | Accumulated fuel injection system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3738921B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6526942B2 (en) | 2000-04-20 | 2003-03-04 | Kabushiki Kaisha Toyoda Jidoshokki Seisakusho | Common rail type fuel injecting device |
| US6719224B2 (en) | 2001-12-18 | 2004-04-13 | Nippon Soken, Inc. | Fuel injector and fuel injection system |
| JP2007024041A (en) * | 2005-07-13 | 2007-02-01 | Delphi Technologies Inc | Injection nozzle |
| JP2007024040A (en) * | 2005-07-13 | 2007-02-01 | Delphi Technologies Inc | Injection nozzle |
| CN114151243A (en) * | 2021-11-19 | 2022-03-08 | 哈尔滨工程大学 | Super-atomized ammonia fuel injector |
| CN114151250A (en) * | 2021-11-19 | 2022-03-08 | 哈尔滨工程大学 | Diesel oil pressurization-liquid ammonia direct injection dual-fuel injector |
-
1996
- 1996-07-04 JP JP17476096A patent/JP3738921B2/en not_active Expired - Lifetime
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6526942B2 (en) | 2000-04-20 | 2003-03-04 | Kabushiki Kaisha Toyoda Jidoshokki Seisakusho | Common rail type fuel injecting device |
| US6719224B2 (en) | 2001-12-18 | 2004-04-13 | Nippon Soken, Inc. | Fuel injector and fuel injection system |
| JP2007024041A (en) * | 2005-07-13 | 2007-02-01 | Delphi Technologies Inc | Injection nozzle |
| JP2007024040A (en) * | 2005-07-13 | 2007-02-01 | Delphi Technologies Inc | Injection nozzle |
| CN114151243A (en) * | 2021-11-19 | 2022-03-08 | 哈尔滨工程大学 | Super-atomized ammonia fuel injector |
| CN114151250A (en) * | 2021-11-19 | 2022-03-08 | 哈尔滨工程大学 | Diesel oil pressurization-liquid ammonia direct injection dual-fuel injector |
| CN114151250B (en) * | 2021-11-19 | 2023-07-21 | 哈尔滨工程大学 | Diesel supercharging-liquid ammonia direct-injection dual-fuel injector |
| CN114151243B (en) * | 2021-11-19 | 2023-07-21 | 哈尔滨工程大学 | Super atomized ammonia fuel injector |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3738921B2 (en) | 2006-01-25 |
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