JPH0727032A - Pressure accumulator for accumulator fuel injection device - Google Patents
Pressure accumulator for accumulator fuel injection deviceInfo
- Publication number
- JPH0727032A JPH0727032A JP5171469A JP17146993A JPH0727032A JP H0727032 A JPH0727032 A JP H0727032A JP 5171469 A JP5171469 A JP 5171469A JP 17146993 A JP17146993 A JP 17146993A JP H0727032 A JPH0727032 A JP H0727032A
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- fuel
- accumulator
- control valve
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、内燃機関に燃料を供給
する蓄圧式燃料噴射装置に係り、特にその蓄圧器（コモ
ンレール）に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure accumulating fuel injection device for supplying fuel to an internal combustion engine, and more particularly to a pressure accumulator (common rail) thereof.
【０００２】[0002]
【従来の技術】例えば、ディーゼルエンジンに燃料を噴
射する燃料噴射装置の一種として蓄圧式燃料噴射装置が
知られている。このものは燃料供給ポンプから供給され
る高圧燃料を一旦蓄圧器（コモンレール）に蓄え、この
蓄圧器で圧力を均等に調整し、この蓄圧燃料を各気筒の
インジェクタに分配供給し、これらインジェクタを通じ
てそれぞれ気筒に噴射するようになっている。2. Description of the Related Art For example, a pressure accumulation type fuel injection device is known as a type of fuel injection device for injecting fuel into a diesel engine. This one temporarily stores the high-pressure fuel supplied from the fuel supply pump in a pressure accumulator (common rail), adjusts the pressure evenly in this accumulator, distributes and supplies this pressure-accumulated fuel to the injectors of each cylinder, and through these injectors, respectively. It is designed to inject into cylinders.
【０００３】ところで、ディーゼルエンジンの場合、回
転数や負荷の変動によりインジェクタから噴射される噴
射圧を制御すると、燃焼効率や排ガス対策に有効である
ことが知られている。すなわち、回転数や負荷が高い場
合、インジェクタから噴射される燃料の噴射圧を高くす
ると、燃料が微細化されて霧化が促され、よって燃焼効
率が向上し、有害な排ガスが減少する。By the way, in the case of a diesel engine, it is known that controlling the injection pressure injected from an injector by fluctuations in the rotational speed and the load is effective for combustion efficiency and exhaust gas countermeasures. That is, when the number of revolutions and the load are high and the injection pressure of the fuel injected from the injector is increased, the fuel is atomized and atomization is promoted, so that combustion efficiency is improved and harmful exhaust gas is reduced.
【０００４】このため、エンジンの運転状況に応じて噴
射圧を制御する必要があり、よって蓄圧器に蓄える燃料
圧もエンジンの運転状況に応じて変更するようになって
いる。Therefore, it is necessary to control the injection pressure according to the operating condition of the engine, and therefore the fuel pressure stored in the pressure accumulator is also changed according to the operating condition of the engine.
【０００５】[0005]
【発明が解決しようとする課題】しかし、この種の蓄圧
式燃料噴射装置の蓄圧器は、その容量が大きい場合は蓄
圧器内の圧力が安定し、インジェクタに送られる燃料圧
のばらつきが小さくなって噴射圧が安定するが、前記し
たようにエンジンの運転状況の変化により噴射圧を変更
する指令が出された場合は、容量が大きいため圧力伝播
に時間を要し、応答性がよくなく、すなわち圧力追従性
に劣る不具合がある。However, in the pressure accumulator of this type of pressure accumulation type fuel injection device, when the capacity is large, the pressure in the pressure accumulator is stable and the variation in the fuel pressure sent to the injector is small. The injection pressure stabilizes, but if a command to change the injection pressure is issued due to a change in the operating condition of the engine as described above, it takes time to propagate the pressure because the capacity is large, and the responsiveness is poor, That is, there is a problem that pressure followability is poor.
【０００６】これに対し、蓄圧器の容量が小さい場合
は、蓄圧器内の圧力安定性に劣り、インジェクタに送ら
れる燃料圧のばらつきが大きくなって噴射圧の安定性が
低下する。しかし、噴射圧を変更する指令が出された場
合の圧力追従性については優れる利点がある。On the other hand, when the capacity of the pressure accumulator is small, the pressure stability in the pressure accumulator is inferior, the dispersion of the fuel pressure sent to the injector becomes large, and the stability of the injection pressure decreases. However, there is an excellent advantage in pressure followability when a command to change the injection pressure is issued.
【０００７】従来の蓄圧器は容量が一定であり、圧力の
安定性および追従性の両者を同時に満足することができ
なかった。The conventional pressure accumulator has a constant capacity and cannot satisfy both pressure stability and followability at the same time.
【０００８】したがって、本発明の目的とするところ
は、蓄圧燃料の圧力安定化が向上するとともに、圧力変
更指令に対する追従性に優れた蓄圧式燃料噴射装置の蓄
圧器を提供しようとするものである。Therefore, an object of the present invention is to provide a pressure accumulator for a pressure accumulation type fuel injection device which improves the pressure stabilization of the pressure accumulation fuel and is excellent in followability to a pressure change command. .
【０００９】[0009]
【課題を解決するための手段】本発明は上記の目的を達
成するため、燃料供給ポンプから供給される燃料を蓄圧
器に蓄え、この蓄圧器から複数のインジェクタに分配す
る蓄圧式燃料噴射装置に適用するものであり、上記蓄圧
器は、相互に区画された複数の蓄圧室を備えるととも
に、これら複数の蓄圧室を相互に連通する連通路を有
し、この連通路にこの連通路を開閉または通路面積を変
化させる制御弁を設け、この制御弁の作動により蓄圧器
全体の蓄圧容量を可変としたことを特徴とする。In order to achieve the above object, the present invention provides a pressure-accumulation type fuel injection device for accumulating fuel supplied from a fuel supply pump in a pressure accumulator and distributing the fuel from the pressure accumulator to a plurality of injectors. The pressure accumulator includes a plurality of pressure accumulating chambers partitioned from each other, and has a communication passage that communicates the plurality of pressure accumulating chambers with each other, and this communication passage is opened or closed. A feature is that a control valve that changes the passage area is provided, and the pressure accumulation capacity of the entire pressure accumulator is made variable by the operation of this control valve.
【００１０】[0010]
【作用】本発明の構成によれば、蓄圧器の容量が可変と
なるから、噴射圧を一定にする指令が出されている場合
は制御弁により連通路を開いて複数の蓄圧室を導通さ
せ、これにより容量を増して圧力を安定させることがで
き、また、噴射圧変更の指令が出された場合は制御弁に
より連通路を閉じて蓄圧室の連通を遮断し、よって容量
を減じて圧力の追従性を向上させることができる。According to the structure of the present invention, since the capacity of the pressure accumulator becomes variable, the control valve opens the communication passage to bring the plurality of pressure accumulator chambers into conduction when a command for making the injection pressure constant is issued. , This makes it possible to increase the capacity and stabilize the pressure, and when a command to change the injection pressure is issued, the communication path is closed by the control valve to cut off the communication with the accumulator, thus reducing the capacity and reducing the pressure. The followability of can be improved.
【００１１】[0011]
【実施例】以下本発明について、図面に示す一実施例に
もとづき説明する。図２は蓄圧式燃料噴射装置の全体を
示す構成図であり、符号１は燃料タンク、２は低圧燃料
供給ポンプ、３は高圧燃料供給ポンプである。低圧燃料
ポンプ２は燃料タンク１の燃料を高圧燃料ポンプ３に供
給し、この高圧燃料ポンプ３は導入された燃料を昇圧
し、所定の高圧にして蓄圧器（コモンレール）１０に供
給する。上記高圧燃料ポンプ３は、エンジン４の回転に
同期して回転するカム５によりシリンダ６内のピストン
７を往復駆動するようになっており、このピストン７が
上記低圧燃料ポンプ２から送られてきた低圧燃料を加圧
して昇圧する。この高圧燃料はチェックバルブ８および
供給管９を通じてコモンレール１０へ供給される。この
場合、上記高圧燃料ポンプ３には、上記コモンレール１
０へ供給する燃料圧を制御するために供給圧制御用の電
磁弁３０が設けられている。この供給圧制御用電磁弁３
０は後述する電子制御ユニット（ＥＣＵ）５０からの指
令を受けて作動する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 2 is a configuration diagram showing the entire pressure-accumulation fuel injection device. Reference numeral 1 is a fuel tank, 2 is a low-pressure fuel supply pump, and 3 is a high-pressure fuel supply pump. The low-pressure fuel pump 2 supplies the fuel in the fuel tank 1 to the high-pressure fuel pump 3, and the high-pressure fuel pump 3 boosts the pressure of the introduced fuel to a predetermined high pressure and supplies it to the pressure accumulator (common rail) 10. The high-pressure fuel pump 3 reciprocally drives a piston 7 in a cylinder 6 by a cam 5 that rotates in synchronization with the rotation of the engine 4, and the piston 7 is sent from the low-pressure fuel pump 2. The low pressure fuel is pressurized and pressure is increased. This high-pressure fuel is supplied to the common rail 10 through the check valve 8 and the supply pipe 9. In this case, the high pressure fuel pump 3 includes the common rail 1
An electromagnetic valve 30 for controlling the supply pressure is provided to control the fuel pressure supplied to zero. This supply pressure control solenoid valve 3
0 operates upon receiving a command from an electronic control unit (ECU) 50 described later.
【００１２】上記コモンレール１０は、詳細な構成を図
１に示してあり、これにもとづき説明する。コモンレー
ルの本体１１内には、小さな容量の第１の蓄圧室１２
と、これより大きな容量の第２の蓄圧室１３が相互に区
画して形成されている。これら第１の蓄圧室１２と第２
の蓄圧室１３は、これらのほぼ中央部に形成した連通路
１４により相互に連通されている。この連通路１４には
制御弁１５が設置されており、この制御弁１５は連通路
１４を開閉または通路面積を可変する。この制御弁１５
は、例えばパルス制御式電磁開閉弁であり、ソレノイド
１６にパルス電流を流すと、プランジャ１７が作動し、
これにより上記連通路１４を開閉またはその通路面積を
変更するものである。したがって、この制御弁１５の開
閉作動により、第１の蓄圧室１２と第２の蓄圧室１３の
連通および遮断がなされ、これによりコモンレール１０
の容量が変更される。The detailed structure of the common rail 10 is shown in FIG. 1, and description will be made based on this. In the main body 11 of the common rail, a first accumulator 12 having a small capacity is provided.
And a second pressure accumulating chamber 13 having a larger capacity than that is formed so as to be partitioned from each other. These first pressure accumulation chamber 12 and second
The pressure accumulating chambers 13 are communicated with each other by a communication passage 14 formed in the substantially central portion thereof. A control valve 15 is installed in the communication passage 14, and the control valve 15 opens / closes the communication passage 14 or changes the passage area. This control valve 15
Is, for example, a pulse-controlled electromagnetic on-off valve, and when a pulse current is applied to the solenoid 16, the plunger 17 operates,
Thereby, the communication passage 14 is opened / closed or the passage area thereof is changed. Therefore, by the opening / closing operation of the control valve 15, the first pressure accumulating chamber 12 and the second pressure accumulating chamber 13 are communicated with each other and cut off, and thereby the common rail 10 is connected.
The capacity of is changed.
【００１３】上記第１の蓄圧室１２は、前記供給管９を
通じて高圧燃料ポンプ３に通じている。また、この第１
の蓄圧室１２にはこの部屋の燃料圧を検出する圧力セン
サ３５が取り付けられている。The first pressure accumulating chamber 12 communicates with the high pressure fuel pump 3 through the supply pipe 9. Also, this first
A pressure sensor 35 for detecting the fuel pressure in the pressure accumulating chamber 12 is attached to the pressure accumulating chamber 12.
【００１４】上記第１の蓄圧室１２には、図２に示すよ
うに、複数の噴射管２０…が接続されており、これら噴
射管２０…にはそれぞれインジェクタ２１…が接続され
ている。インジェクタ２１…はエンジン４の気筒に対応
して取り付けられている。第１の蓄圧室１２とそれぞれ
の噴射管２０…との間には、図１に示すように、インジ
ェクタ２１…からの反射波がコモンレール１０に伝わる
のを阻止する逆止弁２２が設けられている。As shown in FIG. 2, a plurality of injection pipes 20 are connected to the first pressure accumulating chamber 12, and injectors 21 are connected to the injection pipes 20. The injectors 21 ... Are attached to the cylinders of the engine 4. As shown in FIG. 1, a check valve 22 is provided between the first pressure accumulating chamber 12 and each of the injection pipes 20 to prevent a reflected wave from the injector 21 from being transmitted to the common rail 10. There is.
【００１５】前記電子制御ユニット（ＥＣＵ）５０は、
気筒判別センサ５１、クランク角センサ５２および負荷
センサ５３よりエンジンの回転数および負荷の情報が入
力されるようになっており、これら信号により判断され
るエンジンの運転状況に応じて、インジェクタ２１…か
ら噴射すべき燃料噴射圧、噴射時期および噴射量を決定
する。燃料噴射圧は、前記高圧燃料ポンプ３の供給圧制
御用電磁弁３０を作動させることにより、高圧燃料ポン
プ３からコモンレール１０へ供給する燃料圧力を制御
し、これによりコモンレール１０内の燃料圧力を変える
ようになっている。また、噴射時期および噴射量は、イ
ンジェクタ２１の図示しないニードル弁を電磁作用によ
り作動させ、このニードル弁が噴孔を開くタイミングお
よび閉じるタイミングを制御して調節するようになって
いる。The electronic control unit (ECU) 50 is
Information on the engine speed and load is input from the cylinder discrimination sensor 51, the crank angle sensor 52, and the load sensor 53. Depending on the operating conditions of the engine determined by these signals, the injector 21 ... The fuel injection pressure to be injected, the injection timing and the injection amount are determined. The fuel injection pressure controls the fuel pressure supplied from the high-pressure fuel pump 3 to the common rail 10 by operating the supply pressure control solenoid valve 30 of the high-pressure fuel pump 3, thereby changing the fuel pressure in the common rail 10. It is like this. Further, the injection timing and injection amount are adjusted by operating a needle valve (not shown) of the injector 21 by electromagnetic action, and controlling the timing of opening and closing the injection hole of this needle valve.
【００１６】さらに、上記ＥＣＵ５０は燃料噴射圧を変
える時、同時に上記コモンレール１０の制御弁１５に指
令信号を送り、この制御弁１５を作動させるようになっ
ている。すなわち、制御弁１５は上記ＥＣＵ５０からの
指令信号に応じてパルス電流のデューティ比を０から１
００％に変更し、これによりプランジャ１７を作動させ
て連通路１４の開度を０から１００％に範囲で変更する
ようになっている。Further, when changing the fuel injection pressure, the ECU 50 simultaneously sends a command signal to the control valve 15 of the common rail 10 to operate the control valve 15. That is, the control valve 15 changes the duty ratio of the pulse current from 0 to 1 according to the command signal from the ECU 50.
The opening degree of the communication passage 14 is changed in the range from 0 to 100% by changing the opening degree of the communication passage 14 to 00%.
【００１７】また、コモンレール１０に設けた圧力セン
サ３５は、この検出信号を上記ＥＣＵ５０に送るように
なっている。ＥＣＵ５０は圧力センサ３５にて測定した
第１の蓄圧室１２の圧力状態に応じて、後述するように
上記制御弁１５を作動させるようになっている。The pressure sensor 35 provided on the common rail 10 sends the detection signal to the ECU 50. The ECU 50 operates the control valve 15 as described later according to the pressure state of the first pressure accumulating chamber 12 measured by the pressure sensor 35.
【００１８】このような構成による実施例の蓄圧式燃料
噴射装置について、図３の作動特性図を加えて説明す
る。エンジン４の運転中は、低圧燃料ポンプ２により燃
料タンク１の燃料を高圧燃料ポンプ３に供給し、この高
圧燃料ポンプ３は導入された燃料を昇圧し、所定の圧力
にしてコモンレール１０へ供給する。コモンレール１０
においては、導入した燃料を一時的に蓄えて圧力の均整
を図り、この圧力燃料を噴射管２０…を通じてそれぞれ
のインジェクタ２１…へ分配供給する。上記ＥＣＵ５０
からの指令を受けてインジェクタ２１が作動すると噴孔
が開かれ、この噴孔から圧力燃料が気筒に噴射される。The pressure-accumulation type fuel injection device of the embodiment having such a structure will be described with reference to the operation characteristic diagram of FIG. During operation of the engine 4, the low-pressure fuel pump 2 supplies the fuel in the fuel tank 1 to the high-pressure fuel pump 3. The high-pressure fuel pump 3 boosts the pressure of the introduced fuel and supplies it to the common rail 10 at a predetermined pressure. . Common rail 10
In (1), the introduced fuel is temporarily stored to balance the pressure, and the pressure fuel is distributed and supplied to the injectors 21 ... Through the injection pipes 20 ... ECU 50
When the injector 21 is actuated in response to a command from, the injection hole is opened, and the pressure fuel is injected into the cylinder from this injection hole.
【００１９】エンジンの回転数や負荷が低い状態では、
インジェクタ２１…から噴射すべき燃料の噴射圧は相対
的に低くてよく、このためＥＣＵ５０が高圧燃料ポンプ
３の供給圧制御用電磁弁３０を作動させて高圧燃料ポン
プ３からコモンレール１０へ供給する燃料の圧力を低く
して送る。これによりコモンレール１０内の燃料圧力
は、図３の（ａ）図におけるｐ1 のように、比較的低い
状態に保たれる。このときＥＣＵ５０からの指令によ
り、制御弁１５は図３の（ｃ）図に示す通り開作動して
おり、よって連通路１４を開いている。このため、コモ
ンレール１０は第１の蓄圧室１２と第２の蓄圧室１３が
連通しており、容量が大きくなっている。よって、いず
れかのインジェクタ２１を通じて燃料が噴射される時の
ように、コモンレール１０内に局部的な圧力変動が生じ
ても、大きな容量のコモンレール１０内全体で分散吸収
することができ、全体の圧力変動を少なくすることがで
きる。この結果、他のインジェクタ２１に分配される燃
料圧に影響を及ぼすことがなく、安定した圧力状態を維
持することができる。When the engine speed and load are low,
The injection pressure of the fuel to be injected from the injectors 21 may be relatively low, and therefore the ECU 50 operates the supply pressure control solenoid valve 30 of the high pressure fuel pump 3 to supply the fuel supplied from the high pressure fuel pump 3 to the common rail 10. Lower the pressure and send. As a result, the fuel pressure in the common rail 10 is kept relatively low as indicated by p 1 in FIG. At this time, in response to a command from the ECU 50, the control valve 15 is in the open operation as shown in FIG. 3 (c), and thus the communication passage 14 is opened. Therefore, the common rail 10 has the first pressure accumulation chamber 12 and the second pressure accumulation chamber 13 communicating with each other, and has a large capacity. Therefore, even if a local pressure fluctuation occurs in the common rail 10 as when fuel is injected through any of the injectors 21, it can be dispersed and absorbed in the common rail 10 having a large capacity, and the total pressure can be reduced. Fluctuations can be reduced. As a result, it is possible to maintain a stable pressure state without affecting the fuel pressure distributed to the other injectors 21.
【００２０】エンジンの回転数や負荷が高くなってＥＣ
Ｕ５０が燃料噴射圧を高くする指令を出した場合、ＥＣ
Ｕ５０の指令により高圧燃料ポンプ３の供給圧制御用電
磁弁３０が作動されて高圧燃料ポンプ３からコモンレー
ル１０へ供給する燃料の圧力を、図３の（ａ）図におけ
るｐ2 のように高くして送る。したがって、コモンレー
ル１０内の燃料圧力が上昇する。この燃料圧力は第１の
蓄圧室１２に設けた圧力センサ３５が検出しており、こ
の検出値を上記ＥＣＵ５０に送信する。上記ＥＣＵ５０
は、前記エンジンの回転数や負荷変動にもとづき算出し
た指令燃料圧と、上記圧力センサ３５で検出した実圧力
とを比較し、この差が所定の格差以上、つまり図３の
（ｂ）図に示す所定値Ａに達すると、コモンレール１０
の制御弁１５を閉じるように指令を出す。この指令によ
り制御弁１５は図３の（ｃ）図に示すように、パルス電
流のデューティ比を１００％に変更して全閉状態にな
る。このため連通路１４が閉じられ、コモンレール１０
は第１の蓄圧室１２と第２の蓄圧室１３の連通が絶た
れ、第１の蓄圧室１２のみが高圧燃料ポンプ３側および
インジェクタ２１…側に通じ、すなわち容量が減少され
る。よって、高圧燃料ポンプ３から供給される高圧燃料
ｐ2 は第１の蓄圧室１２のみに送られ、このときコモン
レール１０内の容量が小さいので、第１の蓄圧室１２の
圧力上昇が素早くなされ、圧力上昇に対する応答性が向
上する。この結果、各インジェクタ２１…に高圧燃料ｐ
2 を迅速に分配するようになり、各インジェクタ２１…
で直ちに高圧噴射がなされるので、燃料の微細化、つま
り霧化を促し、燃焼効率を上昇させることができる。When the engine speed and load increase, EC
If U50 issues a command to increase the fuel injection pressure, EC
The solenoid valve 30 for controlling the supply pressure of the high-pressure fuel pump 3 is operated by the command of U50, and the pressure of the fuel supplied from the high-pressure fuel pump 3 to the common rail 10 is increased as shown by p 2 in FIG. 3 (a). Send it. Therefore, the fuel pressure in the common rail 10 increases. The fuel pressure is detected by the pressure sensor 35 provided in the first pressure accumulating chamber 12, and the detected value is transmitted to the ECU 50. ECU 50
Compares the command fuel pressure calculated based on the engine speed and load fluctuation with the actual pressure detected by the pressure sensor 35, and the difference is equal to or more than a predetermined gap, that is, in FIG. When the specified value A is reached, the common rail 10
A command is issued to close the control valve 15 of. By this command, the control valve 15 changes the duty ratio of the pulse current to 100% and becomes the fully closed state, as shown in FIG. 3 (c). Therefore, the communication passage 14 is closed and the common rail 10
The communication between the first pressure accumulating chamber 12 and the second pressure accumulating chamber 13 is cut off, and only the first pressure accumulating chamber 12 communicates with the high pressure fuel pump 3 side and the injector 21 side, that is, the capacity is reduced. Therefore, the high-pressure fuel p 2 supplied from the high-pressure fuel pump 3 is sent only to the first pressure accumulating chamber 12, and the capacity in the common rail 10 is small at this time, so that the pressure in the first accumulating chamber 12 rises quickly. The responsiveness to pressure increase is improved. As a result, the high-pressure fuel p is supplied to each injector 21 ...
2 can be quickly distributed, and each injector 21 ...
Since the high-pressure injection is immediately performed in, the atomization of the fuel, that is, atomization can be promoted and the combustion efficiency can be increased.
【００２１】図３の（ａ）図においては、実線で示す指
令値の変動特性に対して、制御弁１５により連通路１４
を遮断制御した場合の実際圧力の変動を同（ａ）図の破
線で示し、また制御弁１５により連通路１４を遮断しな
い場合の実際圧力変動を同（ａ）図の一点鎖線で示す。
これらの特性から、制御弁１５により連通路１４を制御
する方が圧力応答性に優れることが理解できる。In FIG. 3 (a), the control valve 15 controls the communication passage 14 for the variation of the command value indicated by the solid line.
The fluctuation of the actual pressure in the case of shut-off control is shown by the broken line in the same figure (a), and the actual pressure fluctuation when the communication valve 14 is not shut off by the control valve 15 is shown by the dashed line in the same figure.
From these characteristics, it can be understood that controlling the communication passage 14 with the control valve 15 is superior in pressure response.
【００２２】前記ＥＣＵ５０からの指令値の発信タイミ
ングと、第１の蓄圧室１２の圧力変動とは若干のタイミ
ング遅れを生じるので、指令燃料圧と圧力センサ３５で
検出した実圧力との間には時間差分の圧力差を生じ、こ
の圧力差が図３の（ｂ）図に示すＡを越えると上記した
ように制御弁１５が作動して上記連通路１４を閉じる。
そして、制御弁１５が閉じた直後は指令燃料圧と第１の
蓄圧室１２の圧力差がさらに大きくなるが、制御弁１５
が閉じることにより第１の蓄圧室１２の圧力が上昇する
ので両者の圧力差が減少に転じる。そして、この圧力差
が図３の（ｂ）図に示すＢ以下になると、ＥＣＵ５０は
制御弁１５を開くように指令を出す。この指令により制
御弁１５は図３の（ｃ）図におけるIIに示すように、開
き動作する。よって、第１の蓄圧室１２と第２の蓄圧室
１３が再び連通され、コモンレール１０の容量が増大さ
れる。すなわち、このときコモンレール１０は燃料を高
圧状態で蓄圧し、この高圧の状態で安定させることがで
きる。Since there is a slight timing delay between the timing at which the command value is transmitted from the ECU 50 and the pressure fluctuation in the first pressure accumulating chamber 12, there is a delay between the command fuel pressure and the actual pressure detected by the pressure sensor 35. When a pressure difference due to a time difference is generated, and the pressure difference exceeds A shown in FIG. 3B, the control valve 15 operates as described above to close the communication passage 14.
Immediately after the control valve 15 is closed, the command fuel pressure and the pressure difference between the first pressure accumulating chamber 12 are further increased.
Is closed, the pressure in the first pressure accumulating chamber 12 rises, and the pressure difference between the two is reduced. Then, when the pressure difference becomes equal to or less than B shown in FIG. 3B, the ECU 50 issues a command to open the control valve 15. This command causes the control valve 15 to open, as indicated by II in FIG. 3 (c). Therefore, the first pressure accumulating chamber 12 and the second pressure accumulating chamber 13 are connected again, and the capacity of the common rail 10 is increased. That is, at this time, the common rail 10 accumulates fuel in a high pressure state and can stabilize it in this high pressure state.
【００２３】なお、上記制御弁１５の開弁圧Ａと閉弁圧
Ｂには差をもたせてあり（Ａ＞Ｂ）、これによりヒステ
リシスを与えて作動を確実に行うようにしてある。There is a difference between the valve opening pressure A and the valve closing pressure B of the control valve 15 (A> B), whereby hysteresis is given to ensure the operation.
【００２４】また、制御弁１５が開く場合は、図３の
（ｃ）図における角度αで示すように、徐々に開く。こ
れは、制御弁１５に供給するパルス電流のデューティ比
を１００％から０％にゆっくり変更することにより実現
できる。制御弁１５を瞬間的に開くと、第１の蓄圧室１
２の高圧と第２の蓄圧室１３の低圧が導通して圧力が急
激に変動し、脈動などが生じて各インジェクタからに噴
射量がばらつく等の心配があるが、制御弁１５を徐々に
開くことにより、上記の不具合を解消することができ
る。When the control valve 15 is opened, it is gradually opened as indicated by the angle α in FIG. 3 (c). This can be realized by slowly changing the duty ratio of the pulse current supplied to the control valve 15 from 100% to 0%. When the control valve 15 is opened momentarily, the first accumulator 1
There is a concern that the high pressure of 2 and the low pressure of the second pressure accumulating chamber 13 are electrically connected to each other to cause the pressure to fluctuate abruptly, causing pulsation and the like to cause variations in the injection amount from each injector, but the control valve 15 is gradually opened As a result, the above problems can be resolved.
【００２５】なお、上記実施例の制御弁１５は、パルス
電流により作動される電磁駆動式の弁で構成し、そのデ
ューティ比を０から１００％に変更することにより開度
を制御する弁を示したが、本発明はこれに限らず、例え
ばロータリバルブ等により連通路１４の開度を制御する
ようにしてもよい。The control valve 15 of the above embodiment is an electromagnetically driven valve which is operated by a pulse current and whose opening is controlled by changing its duty ratio from 0 to 100%. However, the present invention is not limited to this, and the opening degree of the communication passage 14 may be controlled by, for example, a rotary valve or the like.
【００２６】[0026]
【発明の効果】以上説明したように本発明によると、蓄
圧器の容量を可変としたから、噴射圧を一定にする指令
が出されている場合は複数の蓄圧室を導通させて容量を
増し、よって圧力を安定させることができ、また、噴射
圧変更の指令が出された場合は複数の蓄圧室の連通を遮
断して容量を減じ、これにより圧力の追従性を向上させ
ることができる。したがって、単一の蓄圧器により圧力
安定性と圧力追従性の両機能を満足することができるな
どの利点がある。As described above, according to the present invention, the capacity of the pressure accumulator is variable. Therefore, when a command to make the injection pressure constant is issued, a plurality of pressure accumulators are connected to increase the capacity. Therefore, the pressure can be stabilized, and when a command to change the injection pressure is issued, the communication between the plurality of pressure accumulating chambers is cut off to reduce the capacity, thereby improving the pressure followability. Therefore, there is an advantage that a single pressure accumulator can satisfy both functions of pressure stability and pressure followability.
【図１】本発明の一実施例を示す蓄圧器の断面図。FIG. 1 is a sectional view of a pressure accumulator showing an embodiment of the present invention.
【図２】同実施例の蓄圧式燃料噴射装置の全体を概略的
に示す構成図。FIG. 2 is a configuration diagram schematically showing the entire pressure accumulation type fuel injection device of the embodiment.
【図３】同実施例の作動特性図。FIG. 3 is an operating characteristic diagram of the embodiment.
１…燃料タンク ２…低圧燃料供給
ポンプ ３…高圧燃料供給ポンプ ４…エンジン １０…蓄圧器（コモンレール） １１…コモンレー
ルの本体 １２…第１の蓄圧室 １３…第２の蓄圧
室 １４…連通路 １５…制御弁 ２０…噴射管 ２１…インジェク
タ ３０…供給圧制御用電磁弁 ３５…圧力センサ ５０…電子制御ユニット（ＥＣＵ）DESCRIPTION OF SYMBOLS 1 ... Fuel tank 2 ... Low-pressure fuel supply pump 3 ... High-pressure fuel supply pump 4 ... Engine 10 ... Accumulator (common rail) 11 ... Main body of common rail 12 ... 1st accumulator 13 ... 2nd accumulator 14 ... Communication passage 15 ... Control valve 20 ... Injection pipe 21 ... Injector 30 ... Supply pressure control solenoid valve 35 ... Pressure sensor 50 ... Electronic control unit (ECU)
Claims (1)
圧器に蓄え、この蓄圧器から複数のインジェクタに分配
する蓄圧式燃料噴射装置において、 上記蓄圧器は、相互に区画された複数の蓄圧室を備える
とともに、これら複数の蓄圧室を相互に連通する連通路
を有し、この連通路にこの連通路を開閉または通路面積
を変化させる制御弁を設け、この制御弁の作動により蓄
圧器全体の蓄圧容量を可変としたことを特徴とする蓄圧
式燃料噴射装置の蓄圧器。1. A pressure-accumulation fuel injection device for accumulating fuel supplied from a fuel supply pump in a pressure accumulator and distributing the fuel from the pressure accumulator to a plurality of injectors, wherein the pressure accumulator is a plurality of pressure accumulation chambers partitioned from each other. And has a communication passage that communicates these pressure accumulating chambers with each other, and a control valve that opens or closes this communication passage or changes the passage area is provided in this communication passage. An accumulator for a pressure-accumulation type fuel injection device, characterized in that the accumulator capacity is variable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17146993A JP3293248B2 (en) | 1993-07-12 | 1993-07-12 | Accumulator of accumulator type fuel injection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17146993A JP3293248B2 (en) | 1993-07-12 | 1993-07-12 | Accumulator of accumulator type fuel injection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0727032A true JPH0727032A (en) | 1995-01-27 |
| JP3293248B2 JP3293248B2 (en) | 2002-06-17 |
Family
ID=15923691
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17146993A Expired - Fee Related JP3293248B2 (en) | 1993-07-12 | 1993-07-12 | Accumulator of accumulator type fuel injection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3293248B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0887544A1 (en) * | 1997-06-27 | 1998-12-30 | Robert Bosch Gmbh | Fuel injection system for internal combustion engines |
| JP2010528205A (en) * | 2007-05-23 | 2010-08-19 | インターロッキング ビルディングス ピーティーワイ リミテッド | Manufacturing and installation method of high pressure liquid LPG fuel supply device and dual or mixed fuel supply system |
| DE102011112376A1 (en) * | 2011-09-02 | 2013-03-07 | Poppe & Potthoff Gmbh | Fuel rail for use in common-rail injection system of diesel engine, has connection fittings connected to outer side of base body, where one of fittings connect high-pressure supply line and branch pipe that is attached with branch line |
-
1993
- 1993-07-12 JP JP17146993A patent/JP3293248B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0887544A1 (en) * | 1997-06-27 | 1998-12-30 | Robert Bosch Gmbh | Fuel injection system for internal combustion engines |
| JP2010528205A (en) * | 2007-05-23 | 2010-08-19 | インターロッキング ビルディングス ピーティーワイ リミテッド | Manufacturing and installation method of high pressure liquid LPG fuel supply device and dual or mixed fuel supply system |
| DE102011112376A1 (en) * | 2011-09-02 | 2013-03-07 | Poppe & Potthoff Gmbh | Fuel rail for use in common-rail injection system of diesel engine, has connection fittings connected to outer side of base body, where one of fittings connect high-pressure supply line and branch pipe that is attached with branch line |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3293248B2 (en) | 2002-06-17 |
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