JP4670821B2

JP4670821B2 - Injector

Info

Publication number: JP4670821B2
Application number: JP2007054697A
Authority: JP
Inventors: 耕平久野
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2007-03-05
Filing date: 2007-03-05
Publication date: 2011-04-13
Anticipated expiration: 2027-03-05
Also published as: JP2008215229A

Description

本発明は、高圧燃料と低圧燃料が切り替えられる差圧室を有し、差圧室が高圧燃料または低圧燃料に切り替えられることで作動する作動器（例えば、増圧器）を備えたインジェクタに関する。 The present invention relates to an injector having a differential pressure chamber in which high-pressure fuel and low-pressure fuel are switched, and an actuator (for example, a pressure intensifier) that operates when the differential pressure chamber is switched to high-pressure fuel or low-pressure fuel.

（既存の技術）
差圧室が高圧燃料または低圧燃料に切り替えられることで作動する作動器を備えたインジェクタの一例として、増圧器を搭載したインジェクタが知られている（例えば、特許文献１参照）。
この種のインジェクタの一例を、図１（ａ）を参照して説明する。
インジェクタ２は、図示上部に切替弁背圧室１１を備える差圧切替弁１２、切替弁背圧室１１の内圧を切り替える電磁弁１３（電動アクチュエータ弁の一例）、図示上部にノズル背圧室１４を備える噴射ノズル１５、中間部に差圧室１６を備える増圧器１７（作動器の一例）を具備する。 (Existing technology)
An injector equipped with a pressure intensifier is known as an example of an injector equipped with an actuator that operates when the differential pressure chamber is switched to high-pressure fuel or low-pressure fuel (see, for example, Patent Document 1).
An example of this type of injector will be described with reference to FIG.
The injector 2 includes a differential pressure switching valve 12 having a switching valve back pressure chamber 11 in the upper part of the figure, an electromagnetic valve 13 (an example of an electric actuator valve) for switching the internal pressure of the switching valve back pressure chamber 11, and a nozzle back pressure chamber 14 in the upper part of the figure. And a pressure intensifier 17 (an example of an actuator) having a differential pressure chamber 16 in the middle.

差圧切替弁１２は、３方切替弁であり、高圧燃料が供給される切替弁背圧室１１が電磁弁１３によって低圧側に連通されることで切替弁背圧室１１が低圧側へ切り替わり、差圧室１６およびノズル背圧室１４の内圧を下げる「低圧切替」を行う。
逆に、電磁弁１３が切替弁背圧室１１と低圧側の連通を遮断することで切替弁背圧室１１が高圧側へ切り替わり、差圧室１６およびノズル背圧室１４の内圧を上げる「高圧切替」を行う。 The differential pressure switching valve 12 is a three-way switching valve, and the switching valve back pressure chamber 11 to which the high pressure fuel is supplied is connected to the low pressure side by the electromagnetic valve 13 so that the switching valve back pressure chamber 11 is switched to the low pressure side. Then, “low pressure switching” is performed to lower the internal pressure of the differential pressure chamber 16 and the nozzle back pressure chamber 14.
On the contrary, when the solenoid valve 13 cuts off the communication between the switching valve back pressure chamber 11 and the low pressure side, the switching valve back pressure chamber 11 is switched to the high pressure side, and the internal pressures of the differential pressure chamber 16 and the nozzle back pressure chamber 14 are increased. "High pressure switching".

電磁弁１３は、通電停止時（ＯＦＦ）に切替弁背圧室１１と低圧側の連通を遮断し、通電時（ＯＮ）に切替弁背圧室１１と低圧側を連通させるものであり、ＯＮで差圧切替弁１２を「低圧切替」させ、ＯＦＦで差圧切替弁１２を「高圧切替」させるものである。
噴射ノズル１５のノズル背圧室１４は、差圧室１６を介して差圧切替弁１２により内圧が切り替わるものであり、差圧切替弁１２の「低圧切替（電磁弁１３のＯＮ）」によりノズル背圧室１４が低圧側へ切り替わることで燃料を噴射し、逆に、差圧切替弁１２の「高圧切替（電磁弁１３のＯＦＦ）」によりノズル背圧室１４が高圧側へ切り替わることで噴射停止を行う。 The solenoid valve 13 shuts off the communication between the switching valve back pressure chamber 11 and the low pressure side when energization is stopped (OFF), and communicates the switching valve back pressure chamber 11 and the low pressure side when energized (ON). Thus, the differential pressure switching valve 12 is “low pressure switched”, and the differential pressure switching valve 12 is “high pressure switched” when OFF.
The internal pressure of the nozzle back pressure chamber 14 of the injection nozzle 15 is switched by the differential pressure switching valve 12 through the differential pressure chamber 16, and the nozzle is set by “low pressure switching (electromagnetic valve 13 ON)” of the differential pressure switching valve 12. Fuel is injected when the back pressure chamber 14 is switched to the low pressure side, and conversely, injection is performed when the nozzle back pressure chamber 14 is switched to the high pressure side by “high pressure switching (electromagnetic valve 13 OFF)” of the differential pressure switching valve 12. Stop.

増圧器１７は、２段の増圧ピストン５１を用いた燃料加圧装置であり、差圧切替弁１２の「低圧切替（電磁弁１３のＯＮ）」により差圧室１６が低圧側へ切り替わることで増圧ピストン５１が下降して、増圧ピストン５１の下部に形成された増圧室５３内の燃料が加圧され、増圧室５３に連通する噴射ノズル１５の燃料溜４４の燃料圧力をレール圧より高める。逆に、差圧切替弁１２の「高圧切替（電磁弁１３のＯＦＦ）」により差圧室１６が高圧側へ切り替わることでリターンスプリング５２の復元力によって増圧ピストン５１が上昇して初期位置へ戻る。
なお、増圧室５３は、一方向弁５４ａを含む燃料通路５４を介してコモンレール１と連通しており、増圧ピストン５１の停止中は、増圧室５３および燃料溜４４の燃料圧力がレール圧に維持される。 The pressure booster 17 is a fuel pressurizing device using a two-stage pressure boosting piston 51, and the differential pressure chamber 16 is switched to the low pressure side by “low pressure switching (electromagnetic valve 13 ON)” of the differential pressure switching valve 12. The pressure-increasing piston 51 is lowered, the fuel in the pressure-increasing chamber 53 formed at the lower part of the pressure-increasing piston 51 is pressurized, and the fuel pressure in the fuel reservoir 44 of the injection nozzle 15 communicating with the pressure-increasing chamber 53 is reduced. Increase from rail pressure. On the contrary, when the differential pressure chamber 16 is switched to the high pressure side by the “high pressure switching (the electromagnetic valve 13 is turned off)” of the differential pressure switching valve 12, the pressure increasing piston 51 is raised by the restoring force of the return spring 52 to the initial position. Return.
The pressure increasing chamber 53 communicates with the common rail 1 through a fuel passage 54 including a one-way valve 54a. While the pressure increasing piston 51 is stopped, the fuel pressure in the pressure increasing chamber 53 and the fuel reservoir 44 is reduced to the rail. Maintained at pressure.

（既存技術の問題点）
インジェクタ２に搭載される差圧切替弁１２を説明する。
差圧切替弁１２は、インジェクタボディ２１の内部方向に摺動自在に支持される切替可動弁２２によって、差圧室１６に通じる燃料通路２６を、高圧燃料が供給される等圧室２３に通じる高圧燃料通路２８、または低圧側に通じる低圧燃料通路２７の一方に切り替えるものである。 (Problems with existing technology)
The differential pressure switching valve 12 mounted on the injector 2 will be described.
The differential pressure switching valve 12 communicates the fuel passage 26 leading to the differential pressure chamber 16 to the equal pressure chamber 23 to which high-pressure fuel is supplied by the switching movable valve 22 slidably supported in the internal direction of the injector body 21. It switches to one of the high pressure fuel passage 28 or the low pressure fuel passage 27 leading to the low pressure side.

切替可動弁２２の上部には、インジェクタボディ２１の上下方向に摺動自在に支持される摺動ピストンが設けられ、その摺動ピストンの下部には、図示上方から下方に向かって上部弁体（第２可動弁に相当）、小径部、下部弁体（第１可動弁に相当）が形成されている。
切替可動弁２２における上部弁体と下部弁体で挟まれる空間（小径部の周囲の空間）によって弁室が形成されており、この弁室は、常に燃料通路２６を介して差圧室１６内と連通する。 A sliding piston that is slidably supported in the vertical direction of the injector body 21 is provided at the upper part of the switching movable valve 22, and an upper valve body (from the upper side to the lower side in the figure) is provided at the lower part of the sliding piston. A second movable valve), a small-diameter portion, and a lower valve body (corresponding to the first movable valve).
A valve chamber is formed by a space (a space around the small diameter portion) sandwiched between the upper valve body and the lower valve body in the switching movable valve 22, and this valve chamber is always in the differential pressure chamber 16 via the fuel passage 26. Communicate with.

切替可動弁２２における上部弁体は、差圧室１６に燃料通路２６を介して連通する弁室と、低圧側に通じる低圧燃料通路２７との連通と遮断の切り替えを行うものであって、差圧室１６と低圧燃料通路２７との開閉を行うものである。
そして、切替可動弁２２の下降に伴って上部弁体が下降すると、上部弁体がインジェクタボディ２１に着座して差圧室１６に通じる弁室と低圧燃料通路２７の連通を遮断し（低圧燃料通路２７を閉じる）、逆に切替可動弁２２の上昇に伴って上部弁体が上昇すると、上部弁体がインジェクタボディ２１から離座して差圧室１６に通じる弁室と低圧燃料通路２７を連通させる（低圧燃料通路２７を開く）。 The upper valve body in the switching movable valve 22 switches communication between the valve chamber communicating with the differential pressure chamber 16 via the fuel passage 26 and the low pressure fuel passage 27 communicating with the low pressure side, and switching between them. The pressure chamber 16 and the low pressure fuel passage 27 are opened and closed.
When the upper valve body is lowered as the switching movable valve 22 is lowered, the upper valve body is seated on the injector body 21 and the communication between the valve chamber leading to the differential pressure chamber 16 and the low pressure fuel passage 27 is cut off (low pressure fuel). On the contrary, when the upper valve body rises as the switching movable valve 22 rises, the upper valve body is separated from the injector body 21 and leads to the differential pressure chamber 16 and the low pressure fuel passage 27. Communicate (open the low-pressure fuel passage 27).

切替可動弁２２における下部弁体は、差圧室１６に燃料通路２６を介して連通する弁室と、等圧室２３に通じる高圧燃料通路２８との連通と遮断の切り替えを行うものであって、差圧室１６と高圧燃料通路２８との開閉を行うものである。
そして、切替可動弁２２の下降に伴って下部弁体が下降すると、下部弁体がインジェクタボディ２１から離座して差圧室１６に通じる弁室と高圧燃料通路２８を連通させ（高圧燃料通路２８を開く）、逆に切替可動弁２２の上昇に伴って下部弁体が上昇すると、下部弁体がインジェクタボディ２１に着座して差圧室１６に通じる弁室と高圧燃料通路２８の連通を遮断する（高圧燃料通路２８を閉じる）。 The lower valve body in the switching movable valve 22 switches communication between the valve chamber communicating with the differential pressure chamber 16 via the fuel passage 26 and the high-pressure fuel passage 28 communicating with the equal pressure chamber 23. The differential pressure chamber 16 and the high pressure fuel passage 28 are opened and closed.
Then, when the lower valve body is lowered as the switching movable valve 22 is lowered, the lower valve body is separated from the injector body 21 and the valve chamber communicating with the differential pressure chamber 16 is communicated with the high pressure fuel passage 28 (high pressure fuel passage). On the other hand, when the lower valve body rises as the switching movable valve 22 rises, the lower valve body sits on the injector body 21 and communicates with the valve chamber leading to the differential pressure chamber 16 and the high-pressure fuel passage 28. Shut off (close high pressure fuel passage 28).

上記で示したように、差圧切替弁１２は、１つの切替可動弁２２に設けられた上部弁体と下部弁体の変位に基づき、差圧室１６に通じる弁室を、低圧燃料通路２７または高圧燃料通路２８の一方に切り替えるものである。
このため、上記で示した差圧切替弁１２は、次の問題がある。
差圧室１６を高圧状態から低圧側へ切り替える際は、切替可動弁２２を上昇変位させ、（１）先ず、上部弁体がインジェクタボディ２１から離座し、（２）次に、下部弁体がインジェクタボディ２１に着座する。
逆に、差圧室１６を低圧状態から高圧側へ切り替える際は、切替可動弁２２を下降変位させ、（１’）先ず、下部弁体がインジェクタボディ２１から離座し、（２’）次に、上部弁体がインジェクタボディ２１に着座する。 As described above, the differential pressure switching valve 12 is configured so that the valve chamber leading to the differential pressure chamber 16 is connected to the low pressure fuel passage 27 based on the displacement of the upper valve body and the lower valve body provided in one switching movable valve 22. Alternatively, one of the high-pressure fuel passages 28 is switched.
For this reason, the differential pressure switching valve 12 described above has the following problems.
When switching the differential pressure chamber 16 from the high pressure state to the low pressure side, the switching movable valve 22 is moved up and displaced. (1) First, the upper valve body is separated from the injector body 21, and (2) Next, the lower valve body Is seated on the injector body 21.
On the contrary, when the differential pressure chamber 16 is switched from the low pressure state to the high pressure side, the switching movable valve 22 is displaced downward (1 ′). First, the lower valve body is separated from the injector body 21, and (2 ′) next. In addition, the upper valve body is seated on the injector body 21.

差圧切替弁１２の切替途中である上記（１）〜（２）の間、および上記（１’）〜（２’）の間では、上部弁体と下部弁体とが、共にインジェクタボディ２１から離座した状態になる。即ち、高圧燃料通路２８と低圧燃料通路２７が弁室を介して連通した状態になる。
このため、コモンレール１から供給された高圧燃料が、高圧燃料通路２８→弁室→低圧燃料通路２７の経路で流出してしまう。この結果、インジェクタ２の高圧燃料の圧力が下がる問題がある。
特開２００６−１６１５６８号公報 Between the above (1) and (2) during the switching of the differential pressure switching valve 12 and between the above (1 ′) and (2 ′), both the upper valve body and the lower valve body are the injector body 21. It is in a state of being separated from. That is, the high pressure fuel passage 28 and the low pressure fuel passage 27 are in communication with each other via the valve chamber.
For this reason, the high-pressure fuel supplied from the common rail 1 flows out through the path of the high-pressure fuel passage 28 → the valve chamber → the low-pressure fuel passage 27. As a result, there is a problem that the pressure of the high-pressure fuel in the injector 2 decreases.
JP 2006-161568 A

本発明は、上記問題点に鑑みてなされたものであり、その目的は、差圧切替弁の切替途中に、高圧燃料通路と低圧燃料通路とが、差圧切替弁を介して連通することのないインジェクタの提供にある。 The present invention has been made in view of the above-described problems, and an object of the present invention is that the high-pressure fuel passage and the low-pressure fuel passage communicate with each other through the differential pressure switching valve during the switching of the differential pressure switching valve. There is no injector offering.

［請求項１、２の手段］
請求項１、２の手段を採用するインジェクタの差圧切替弁は、切替弁背圧室の油圧変化により、差圧室と高圧側との連通を行う高圧燃料通路の開閉を行う高圧切替弁と、切替弁背圧室の油圧変化により、差圧室と低圧側との連通を行う低圧燃料通路の開閉を行う低圧切替弁とを備える。
そして、切替弁背圧室の油圧変化により、差圧室を低圧側に切り替える際は、先ず、高圧切替弁が、高圧燃料通路を閉じ、次に、低圧切替弁が、低圧燃料通路を開く。
また、切替弁背圧室の油圧変化により、差圧室を高圧側に切り替える際は、先ず、低圧切替弁が、低圧燃料通路を閉じ、次に、高圧切替弁が、高圧燃料通路を開く。
このように、差圧切替弁が切り替わる際、切替途中に高圧燃料通路と低圧燃料通路とが同時に開くことがなく、高圧燃料通路と低圧燃料通路とが差圧切替弁を介して連通することがない。
このため、差圧切替弁の切替途中に高圧燃料通路の高圧燃料が、高圧燃料通路→差圧切替弁→低圧燃料通路の経路で流出する不具合がなく、インジェクタに供給される高圧燃料の圧力の低下を防ぐことができる。 [Means of claims 1 and 2 ]
A differential pressure switching valve for an injector that employs the means of claims 1 and 2 includes a high-pressure switching valve that opens and closes a high-pressure fuel passage that communicates between the differential pressure chamber and the high-pressure side due to a change in hydraulic pressure of the switching valve back pressure chamber And a low-pressure switching valve that opens and closes a low-pressure fuel passage that communicates between the differential pressure chamber and the low-pressure side by changing the hydraulic pressure of the switching valve back pressure chamber.
When the differential pressure chamber is switched to the low pressure side due to a change in the hydraulic pressure of the switching valve back pressure chamber, first, the high pressure switching valve closes the high pressure fuel passage, and then the low pressure switching valve opens the low pressure fuel passage.
When the differential pressure chamber is switched to the high pressure side due to a change in the hydraulic pressure of the switching valve back pressure chamber, the low pressure switching valve first closes the low pressure fuel passage, and then the high pressure switching valve opens the high pressure fuel passage.
As described above, when the differential pressure switching valve is switched, the high pressure fuel passage and the low pressure fuel passage are not simultaneously opened during switching, and the high pressure fuel passage and the low pressure fuel passage may be communicated via the differential pressure switching valve. Absent.
Therefore, there is no problem that the high-pressure fuel in the high-pressure fuel passage flows out of the high-pressure fuel passage → the differential pressure switching valve → the low-pressure fuel passage during the switching of the differential pressure switching valve, and the pressure of the high-pressure fuel supplied to the injector is reduced. Decline can be prevented.

［請求項３の手段］
請求項３の手段を採用するインジェクタにおける作動器は、インジェクタ内で噴射圧を増加させる増圧器であり、増圧ピストンは、差圧室が高圧燃料から低圧燃料に切り替えられて変位することで、燃料溜の高圧燃料の増圧作動を行う。 [Means of claim 3 ]
The actuator in the injector that employs the means of claim 3 is a pressure intensifier that increases the injection pressure in the injector, and the pressure increasing piston is displaced by switching the differential pressure chamber from high pressure fuel to low pressure fuel, Increase the pressure of the high pressure fuel in the fuel reservoir.

最良の形態１、２におけるインジェクタは、高圧燃料と低圧燃料が切り替えられる差圧室を有し、この差圧室が高圧燃料または低圧燃料に切り替えられることで作動する作動器（例えば、増圧器）と、高圧燃料が供給される切替弁背圧室の油圧変化により、差圧室の圧力を高圧燃料または低圧燃料に切り替える差圧切替弁と、切替弁背圧室と低圧側との連通または遮断を行い、切替弁背圧室を高圧燃料または低圧燃料に切り替える電動アクチュエータ弁とを備える。
差圧切替弁は、切替弁背圧室の油圧変化により、差圧室と高圧側との連通を行う高圧燃料通路の開閉を行う高圧切替弁と、切替弁背圧室の油圧変化により、差圧室と低圧側との連通を行う低圧燃料通路の開閉を行う低圧切替弁とを備えるものであり、
切替弁背圧室の油圧変化により、差圧室を低圧側に切り替える際に、
先ず、高圧切替弁が、高圧燃料通路を閉じ、
次に、低圧切替弁が、低圧燃料通路を開くように設けられるとともに、
切替弁背圧室の油圧変化により、差圧室を高圧側に切り替える際に、
先ず、低圧切替弁が、低圧燃料通路を閉じ、
次に、高圧切替弁が、高圧燃料通路を開くように設けられる。
そして、高圧切替弁において高圧燃料通路の開閉を行う第１可動弁と、低圧切替弁において低圧燃料通路の開閉を行う第２可動弁とは、独立して可動する独立弁体である。
さらに、最良の形態１のインジェクタにおける高圧切替弁は、第１可動弁の他に、
第１可動弁が高圧燃料通路を開く方向に、第１可動弁を付勢する第１リターンスプリング、
第１可動弁が高圧燃料通路を閉じる方向に、第１可動弁を付勢する第１高圧室を有し、第１リターンスプリングが配置される第１スプリング室に、高圧切替弁における切替弁背圧室が形成される。
また、最良の形態２のインジェクタにおける低圧切替弁は、第２可動弁の他に、
第２可動弁が低圧燃料通路を閉じる方向に、第２可動弁を付勢する第２リターンスプリング、
第２可動弁が低圧燃料通路を開く方向に、第２可動弁を付勢する第２高圧室を有し、
第２リターンスプリングが配置される第２スプリング室に、低圧切替弁における切替弁背圧室が形成される。 The injector in the best mode 1 or 2 has a differential pressure chamber in which high pressure fuel and low pressure fuel are switched, and an actuator (for example, a pressure intensifier) that operates by switching the differential pressure chamber to high pressure fuel or low pressure fuel. And a differential pressure switching valve that switches the pressure in the differential pressure chamber to high pressure fuel or low pressure fuel due to a change in the hydraulic pressure of the switching valve back pressure chamber to which high pressure fuel is supplied, and communication between the switching valve back pressure chamber and the low pressure side And an electric actuator valve for switching the switching valve back pressure chamber to high pressure fuel or low pressure fuel.
The differential pressure changeover valve has a difference between the high pressure changeover valve that opens and closes the high pressure fuel passage that connects the differential pressure chamber and the high pressure side, and the change in hydraulic pressure in the changeover valve backpressure chamber. A low-pressure switching valve that opens and closes a low-pressure fuel passage that communicates between the pressure chamber and the low-pressure side,
When switching the differential pressure chamber to the low pressure side due to the hydraulic pressure change of the switching valve back pressure chamber,
First, the high pressure switching valve closes the high pressure fuel passage,
Next, a low pressure switching valve is provided to open the low pressure fuel passage,
When switching the differential pressure chamber to the high pressure side due to the hydraulic pressure change of the switching valve back pressure chamber,
First, the low pressure switching valve closes the low pressure fuel passage,
Then, the high-pressure switching valve, Ru provided to open the high-pressure fuel passage.
The first movable valve that opens and closes the high-pressure fuel passage in the high-pressure switching valve and the second movable valve that opens and closes the low-pressure fuel passage in the low-pressure switching valve are independent valve bodies that move independently.
Further, the high pressure switching valve in the injector of the best mode 1 is not only the first movable valve,
A first return spring that biases the first movable valve in a direction in which the first movable valve opens the high-pressure fuel passage;
The first movable valve has a first high pressure chamber that urges the first movable valve in a direction to close the high pressure fuel passage, and the first spring chamber in which the first return spring is disposed has a switching valve back in the high pressure switching valve. A pressure chamber is formed.
Further, the low pressure switching valve in the injector of the best mode 2 is, in addition to the second movable valve,
A second return spring that biases the second movable valve in a direction in which the second movable valve closes the low-pressure fuel passage;
A second high pressure chamber for biasing the second movable valve in a direction in which the second movable valve opens the low pressure fuel passage;
A switching valve back pressure chamber in the low pressure switching valve is formed in the second spring chamber in which the second return spring is disposed.

実施例１では、先ず図１（ａ）を参照して本発明が適用されていない既存のインジェクタを搭載する燃料噴射装置の概略構成を「参考例」として説明し、その後で図１（ｂ）を参照して本発明が適用されたインジェクタを「実施例１の特徴」として説明する。
〔参考例の説明〕
燃料噴射装置は、エンジン（例えばディーゼルエンジン：図示しない）の各気筒に燃料噴射を行うコモンレール式燃料噴射装置であり、コモンレール１、インジェクタ２、サプライポンプ（図示しない）、制御装置（図示しない）等によって構成される。 In the first embodiment, first, referring to FIG. 1A, a schematic configuration of a fuel injection device equipped with an existing injector to which the present invention is not applied will be described as a “reference example”, and thereafter, FIG. The injector to which the present invention is applied will be described as “characteristics of the first embodiment”.
[Description of Reference Example]
The fuel injection device is a common rail fuel injection device that injects fuel into each cylinder of an engine (for example, a diesel engine: not shown), such as a common rail 1, an injector 2, a supply pump (not shown), a control device (not shown), and the like. Consists of.

コモンレール１は、インジェクタ２に供給する高圧燃料を蓄圧する周知な蓄圧容器であり、コモンレール１に蓄圧された燃料は、インジェクタ配管を介してインジェクタ２へ供給される。コモンレール１内に蓄圧する燃料圧力（レール圧）は、サプライポンプからコモンレール１に供給されるポンプ吐出量、およびコモンレール１から燃料を溢流させる減圧弁によって調圧される。また、コモンレール１には、プレッシャリミッタが取り付けられており、コモンレール１内のレール圧が限界設定圧を超えた際に開弁して、コモンレール１内のレール圧が限界設定圧以下に抑えられる。減圧弁またはプレッシャリミッタから溢流した燃料は、リリーフ配管を経て燃料タンク３に戻される。なお、減圧弁は、設けられない場合もある。 The common rail 1 is a well-known pressure accumulating container that accumulates high-pressure fuel supplied to the injector 2, and the fuel accumulated in the common rail 1 is supplied to the injector 2 via the injector piping. The fuel pressure (rail pressure) accumulated in the common rail 1 is regulated by a pump discharge amount supplied from the supply pump to the common rail 1 and a pressure reducing valve that causes the fuel to overflow from the common rail 1. Further, a pressure limiter is attached to the common rail 1, and the valve is opened when the rail pressure in the common rail 1 exceeds the limit set pressure, so that the rail pressure in the common rail 1 is suppressed to the limit set pressure or less. The fuel overflowing from the pressure reducing valve or the pressure limiter is returned to the fuel tank 3 through the relief pipe. Note that the pressure reducing valve may not be provided.

インジェクタ２は、エンジンの各気筒毎に搭載されるものであり、コモンレール１より分岐する複数のインジェクタ配管の下流端に接続されて、コモンレール１に蓄圧された高圧燃料を各気筒内に噴射供給するもので、その具体的な構成は後述する。
なお、インジェクタ２からのリーク燃料も、リリーフ配管を経て燃料タンク３に戻される。 The injector 2 is mounted for each cylinder of the engine, is connected to the downstream end of a plurality of injector pipes branched from the common rail 1, and injects and supplies high-pressure fuel accumulated in the common rail 1 into each cylinder. The specific configuration will be described later.
Note that the leaked fuel from the injector 2 is also returned to the fuel tank 3 via the relief pipe.

サプライポンプは、コモンレール１へ高圧燃料を圧送する高圧燃料ポンプであり、燃料タンク３内の燃料をサプライポンプ内へ吸引するフィードポンプと、フィードポンプが吸い上げた燃料を加圧してコモンレール１へ圧送する高圧ポンプとを備える。フィードポンプおよび高圧ポンプは共通のカムシャフトによって駆動されるものであり、このカムシャフトは、エンジンによって回転駆動される。 The supply pump is a high-pressure fuel pump that pumps high-pressure fuel to the common rail 1. A feed pump that sucks the fuel in the fuel tank 3 into the supply pump, and pressurizes the fuel sucked up by the feed pump and pumps the fuel to the common rail 1. A high-pressure pump. The feed pump and the high-pressure pump are driven by a common camshaft, and this camshaft is rotationally driven by the engine.

サプライポンプには、フィードポンプから高圧ポンプの加圧室内に燃料を導く燃料流路に、その燃料流路の開度度合を調整するためのＳＣＶ（吸入調量弁）が搭載されている。ＳＣＶは、制御装置からのポンプ駆動信号によって制御されることにより、加圧室内に吸入される燃料の吸入量を調整し、コモンレール１へ圧送する燃料の吐出量を変更する調量バルブであり、コモンレール１へ圧送する燃料の吐出量を調整することによりレール圧を調整する。即ち、制御装置はＳＣＶを制御することにより、レール圧を車両走行状態に応じた圧力に制御する。 In the supply pump, an SCV (suction metering valve) for adjusting the degree of opening of the fuel flow path is mounted on the fuel flow path for guiding fuel from the feed pump to the pressurizing chamber of the high pressure pump. The SCV is a metering valve that adjusts the amount of fuel sucked into the pressurizing chamber and changes the discharge amount of fuel pumped to the common rail 1 by being controlled by a pump drive signal from the control device. The rail pressure is adjusted by adjusting the discharge amount of fuel pumped to the common rail 1. That is, the control device controls the rail pressure to a pressure corresponding to the vehicle running state by controlling the SCV.

（インジェクタ２の説明）
次に、本発明が適用されていない参考例のインジェクタ２の構成を、図１の上側を上、図１の下側を下として説明する。なお、この上下は説明のためのものであり、実際の搭載方向に関わるものではない。
インジェクタ２は、上部に形成された切替弁背圧室１１の内圧変化により切り替えられる差圧切替弁１２と、切替弁背圧室１１の内圧を変化させる電磁弁１３と、上部に形成されたノズル背圧室１４の内圧変化により噴射と噴射停止が切り替えられる噴射ノズル１５と、中間部に形成された差圧室１６の内圧変化により増圧と増圧停止（初期位置へ戻るを含む）が切り替えられる増圧器１７とを備える。 (Description of injector 2)
Next, the configuration of the injector 2 of the reference example to which the present invention is not applied will be described with the upper side in FIG. 1 as the upper side and the lower side in FIG. 1 as the lower side. Note that the upper and lower sides are for explanation, and do not relate to the actual mounting direction.
The injector 2 includes a differential pressure switching valve 12 that is switched by an internal pressure change of the switching valve back pressure chamber 11 formed in the upper part, an electromagnetic valve 13 that changes the internal pressure of the switching valve back pressure chamber 11, and a nozzle formed in the upper part. Switching between injection nozzle 15 for switching between injection and injection stop by changing internal pressure of back pressure chamber 14 and pressure increase and stop of pressure increase (including return to initial position) by change of internal pressure of differential pressure chamber 16 formed at intermediate portion And a pressure intensifier 17 to be provided.

（差圧切替弁１２の説明）
差圧切替弁１２は、３方切替弁であり、インジェクタボディ２１の上下方向に摺動自在に支持される切替可動弁２２によって、差圧室１６に通じる燃料通路２６を、高圧燃料が供給される等圧室２３に通じる高圧燃料通路２８、または低圧側に通じる低圧燃料通路２７の一方に切り替えるものである。 (Description of differential pressure switching valve 12)
The differential pressure switching valve 12 is a three-way switching valve, and high pressure fuel is supplied to the fuel passage 26 leading to the differential pressure chamber 16 by a switching movable valve 22 slidably supported in the vertical direction of the injector body 21. The high-pressure fuel passage 28 leading to the constant pressure chamber 23 or the low-pressure fuel passage 27 leading to the low-pressure side is switched.

切替可動弁２２の上部には、インジェクタボディ２１の上下方向に摺動自在に支持される摺動ピストンが設けられ、その摺動ピストンの上面に切替弁背圧室１１が形成されている。この切替弁背圧室１１は、コモンレール１から高圧燃料が供給される等圧室２３に通じる高圧燃料通路２４と接続されており、等圧室２３に供給される高圧燃料が高圧燃料通路２４、およびこの高圧燃料通路２４に設けられた入口オリフィス２４ａを介して供給されるようになっている。
切替可動弁２２における摺動ピストンの下部には、上方から下方に向かって上部弁体（第２可動弁に相当）、小径部、下部弁体（第１可動弁に相当）が形成されている。
切替可動弁２２における上部弁体と下部弁体で挟まれる空間（小径部の周囲の空間）によって弁室が形成されており、この弁室は、常に燃料通路２６を介して差圧室１６内と連通する。 A sliding piston that is slidably supported in the vertical direction of the injector body 21 is provided on the upper portion of the switching movable valve 22, and the switching valve back pressure chamber 11 is formed on the upper surface of the sliding piston. The switching valve back pressure chamber 11 is connected to a high pressure fuel passage 24 that leads to a constant pressure chamber 23 to which high pressure fuel is supplied from the common rail 1, and the high pressure fuel supplied to the constant pressure chamber 23 is connected to the high pressure fuel passage 24, And it is supplied through an inlet orifice 24 a provided in the high-pressure fuel passage 24.
An upper valve body (corresponding to the second movable valve), a small diameter portion, and a lower valve body (corresponding to the first movable valve) are formed from the upper side to the lower side of the sliding piston in the switching movable valve 22. .
A valve chamber is formed by a space (a space around the small diameter portion) sandwiched between the upper valve body and the lower valve body in the switching movable valve 22, and this valve chamber is always in the differential pressure chamber 16 via the fuel passage 26. Communicate with.

切替可動弁２２における上部弁体は、差圧室１６に燃料通路２６を介して連通する弁室と、低圧側に通じる低圧燃料通路２７との連通と遮断の切り替えを行うものである。言葉を代えると、切替可動弁２２における上部弁体は、差圧室１６と低圧燃料通路２７との開閉を行うものである。
そして、切替可動弁２２の下降に伴って上部弁体が下降すると、上部弁体がインジェクタボディ２１に着座して差圧室１６に通じる弁室と低圧燃料通路２７の連通を遮断し（低圧燃料通路２７を閉じる）、逆に切替可動弁２２の上昇に伴って上部弁体が上昇すると、上部弁体がインジェクタボディ２１から離座して差圧室１６に通じる弁室と低圧燃料通路２７を連通させる（低圧燃料通路２７を開く）。 The upper valve body in the switching movable valve 22 switches communication between the valve chamber communicating with the differential pressure chamber 16 via the fuel passage 26 and the low pressure fuel passage 27 communicating with the low pressure side. In other words, the upper valve body in the switching movable valve 22 opens and closes the differential pressure chamber 16 and the low pressure fuel passage 27.
When the upper valve body is lowered as the switching movable valve 22 is lowered, the upper valve body is seated on the injector body 21 and the communication between the valve chamber leading to the differential pressure chamber 16 and the low pressure fuel passage 27 is cut off (low pressure fuel). On the contrary, when the upper valve body rises as the switching movable valve 22 rises, the upper valve body is separated from the injector body 21 and leads to the differential pressure chamber 16 and the low pressure fuel passage 27. Communicate (open the low-pressure fuel passage 27).

切替可動弁２２における下部弁体は、差圧室１６に燃料通路２６を介して連通する弁室と、等圧室２３に通じる高圧燃料通路２８との連通と遮断の切り替えを行うものである。言葉を代えると、切替可動弁２２における下部弁体は、差圧室１６と高圧燃料通路２８との開閉を行うものである。
そして、切替可動弁２２の下降に伴って下部弁体が下降すると、下部弁体がインジェクタボディ２１から離座して差圧室１６に通じる弁室と高圧燃料通路２８を連通させ（高圧燃料通路２８を開く）、逆に切替可動弁２２の上昇に伴って下部弁体が上昇すると、下部弁体がインジェクタボディ２１に着座して差圧室１６に通じる弁室と高圧燃料通路２８の連通を遮断する（高圧燃料通路２８を閉じる）。 The lower valve body in the switching movable valve 22 switches communication between the valve chamber communicating with the differential pressure chamber 16 via the fuel passage 26 and the high-pressure fuel passage 28 communicating with the isobaric chamber 23. In other words, the lower valve body in the switching movable valve 22 opens and closes the differential pressure chamber 16 and the high pressure fuel passage 28.
Then, when the lower valve body is lowered as the switching movable valve 22 is lowered, the lower valve body is separated from the injector body 21 and the valve chamber communicating with the differential pressure chamber 16 is communicated with the high pressure fuel passage 28 (high pressure fuel passage). On the other hand, when the lower valve body rises as the switching movable valve 22 rises, the lower valve body sits on the injector body 21 and communicates with the valve chamber leading to the differential pressure chamber 16 and the high-pressure fuel passage 28. Shut off (close high pressure fuel passage 28).

差圧切替弁１２は、上記の構成を採用することで、電磁弁１３が低圧燃料通路２５を開くことで、切替弁背圧室１１の内圧が低下して切替可動弁２２が上昇し、差圧室１６の連通先が低圧燃料通路２７に切り替わることで、増圧器１７の差圧室１６、およびこの差圧室１６に連通する噴射ノズル１５のノズル背圧室１４の内圧を下げる「低圧切替」を実行する。
逆に、差圧切替弁１２は、電磁弁１３が低圧燃料通路２５を閉じることで、切替弁背圧室１１の内圧が上昇して切替可動弁２２が下降し、差圧室１６の連通先が高圧燃料通路２８に切り替わることで、増圧器１７の差圧室１６、およびこの差圧室１６に連通する噴射ノズル１５のノズル背圧室１４の内圧を上げる「高圧切替」を実行する。
なお、切替可動弁２２に一方向（例えば、上方）へ向かうバネ力を作用させるものであっても良い。 By adopting the above-described configuration, the differential pressure switching valve 12 opens the low pressure fuel passage 25 so that the internal pressure of the switching valve back pressure chamber 11 decreases and the switching movable valve 22 rises. By switching the communication destination of the pressure chamber 16 to the low pressure fuel passage 27, “low pressure switching” is performed to lower the internal pressure of the differential pressure chamber 16 of the pressure intensifier 17 and the nozzle back pressure chamber 14 of the injection nozzle 15 communicating with the differential pressure chamber 16. ”Is executed.
On the contrary, the differential pressure switching valve 12 is configured so that the internal pressure of the switching valve back pressure chamber 11 is increased and the switching movable valve 22 is lowered due to the electromagnetic valve 13 closing the low pressure fuel passage 25, and the communication destination of the differential pressure chamber 16 is reduced. Is switched to the high pressure fuel passage 28 to execute “high pressure switching” for increasing the internal pressure of the differential pressure chamber 16 of the pressure intensifier 17 and the nozzle back pressure chamber 14 of the injection nozzle 15 communicating with the differential pressure chamber 16.
It should be noted that a spring force directed in one direction (for example, upward) may be applied to the switching movable valve 22.

（電磁弁１３の説明）
電磁弁１３は、例えば、インジェクタボディ２１の上部に締結固定されるものであり、低圧燃料通路２５における出口オリフィス２５ａの開閉を行う可動弁３１、低圧燃料通路２５を閉じる方向へ可動弁３１を付勢するリターンスプリング３２、および可動弁３１を磁気吸引して低圧燃料通路２５を開かせる電磁駆動部３３から構成される。
可動弁３１は、上下方向（軸方向）へ摺動自在に支持され、下端面において低圧燃料通路２５の出口オリフィス２５ａを閉塞可能な弁体３１ａと、この弁体３１ａの上部に固定された略円板形状を呈する磁性体製のアーマチャ３１ｂとからなる。
電磁駆動部３３は、絶縁被覆が形成された導電線を多数巻回してなるコイル３４と、このコイル３４を収容する磁性体製のステータ３５とからなる。 (Description of solenoid valve 13)
For example, the electromagnetic valve 13 is fastened and fixed to the upper portion of the injector body 21, and is provided with a movable valve 31 that opens and closes the outlet orifice 25 a in the low-pressure fuel passage 25, and a movable valve 31 in a direction to close the low-pressure fuel passage 25. The return spring 32 is energized, and the electromagnetic drive unit 33 opens the low-pressure fuel passage 25 by magnetically attracting the movable valve 31.
The movable valve 31 is supported so as to be slidable in the vertical direction (axial direction), and has a valve body 31a capable of closing the outlet orifice 25a of the low-pressure fuel passage 25 at the lower end surface, and a substantially fixed upper part of the valve body 31a. It consists of a magnetic armature 31b having a disc shape.
The electromagnetic drive unit 33 includes a coil 34 formed by winding a number of conductive wires on which an insulating coating is formed, and a magnetic stator 35 that accommodates the coil 34.

そして、電磁駆動部３３は、コイル３４が通電（ＯＮ）されることでアーマチャ３１ｂを上方へ磁気吸引して低圧燃料通路２５の出口オリフィス２５ａを開き、切替弁背圧室１１を低圧側へ連通させ、コイル３４の通電が停止（ＯＦＦ）されることでアーマチャ３１ｂがリターンスプリング３２の作用で低圧燃料通路２５の出口オリフィス２５ａを閉塞し、切替弁背圧室１１と低圧側の連通を遮断する。
この作動により、電磁弁１３のＯＮで差圧切替弁１２を「低圧切替」させ、ＯＦＦで差圧切替弁１２を「高圧切替」させることができる。 Then, when the coil 34 is energized (ON), the electromagnetic drive unit 33 magnetically attracts the armature 31b upward to open the outlet orifice 25a of the low pressure fuel passage 25, and communicates the switching valve back pressure chamber 11 to the low pressure side. When the energization of the coil 34 is stopped (OFF), the armature 31b closes the outlet orifice 25a of the low pressure fuel passage 25 by the action of the return spring 32, and disconnects the switching valve back pressure chamber 11 from the low pressure side. .
By this operation, the differential pressure switching valve 12 can be “low pressure switched” when the electromagnetic valve 13 is ON, and the high pressure switching valve 12 can be “high pressure switched” when the electromagnetic valve 13 is OFF.

（噴射ノズル１５の説明）
噴射ノズル１５は、燃料の噴射と停止を切り替えるものであり、インジェクタボディ２１の下部に締結されるノズルホルダ４１の内部において上下方向（軸方向）へ摺動自在に支持されるニードル４２を備え、このニードル４２は、スプリング４２ａの付勢力により下方へ付勢されている。
ニードル４２は、上部に設けられたニードル摺動部がノズルホルダ４１内において摺動自在に支持されるものであり、ニードル４２の下端円錐部がノズルホルダ４１の下端内面に形成された環状シートに着座または離座する。なお、ノズルホルダ４１の下端には、環状シートの内側と外部とを連通する噴孔４３が複数形成されている。 (Description of injection nozzle 15)
The injection nozzle 15 switches between fuel injection and stop, and includes a needle 42 that is slidably supported in the vertical direction (axial direction) inside a nozzle holder 41 fastened to the lower portion of the injector body 21. The needle 42 is urged downward by the urging force of the spring 42a.
The needle 42 is configured such that a needle sliding portion provided at an upper portion is slidably supported in the nozzle holder 41, and a lower end conical portion of the needle 42 is formed on an annular sheet formed on the lower end inner surface of the nozzle holder 41. Sit or leave. Note that a plurality of nozzle holes 43 that communicate the inside and the outside of the annular sheet are formed at the lower end of the nozzle holder 41.

ニードル４２の中間部には、ニードル４２とノズルホルダ４１に囲まれる空間によって燃料溜４４が形成されている。この燃料溜４４は、後述する増圧室５３と燃料通路４５を介して連通しており、増圧室５３の燃料圧力が燃料溜４４に供給される。また、燃料溜４４は、ニードル４２の下側とノズルホルダ４１の隙間に形成される下側空間と連通しており、ニードル４２の離座時に燃料溜４４に供給された燃料が下側空間を通って噴孔４３から噴射される。なお、燃料溜４４および下側空間に供給される高圧燃料は、ニードル４２の径差に作用して、ニードル４２に対して上向き（離座方向）の力を発生させる。 A fuel reservoir 44 is formed at a middle portion of the needle 42 by a space surrounded by the needle 42 and the nozzle holder 41. The fuel reservoir 44 communicates with a pressure increasing chamber 53 described later via a fuel passage 45, and the fuel pressure in the pressure increasing chamber 53 is supplied to the fuel reservoir 44. Further, the fuel reservoir 44 communicates with the lower space formed in the gap between the lower side of the needle 42 and the nozzle holder 41, and the fuel supplied to the fuel reservoir 44 when the needle 42 is separated from the lower space. It is injected from the nozzle hole 43 through. The high pressure fuel supplied to the fuel reservoir 44 and the lower space acts on the diameter difference of the needle 42 and generates an upward force (separating direction) on the needle 42.

ニードル摺動部の上部には、燃料の圧力によってニードル４２に下向き（着座方向）の力を発生させるためのノズル背圧室１４が形成されている。このノズル背圧室１４は、ニードル摺動部の上面、インジェクタボディ２１およびノズルホルダ４１で囲まれる空間で形成される。ノズル背圧室１４は、増圧器１７の差圧室１６と燃料通路４６を介して接続されている。この燃料通路４６には、流路面積を絞るオリフィス４６ａが設けられるとともに、このオリフィス４６ａと並列に一方向弁４６ｂが設けられている。
この一方向弁４６ｂは、差圧室１６からノズル背圧室１４へ燃料を流し、逆にノズル背圧室１４から差圧室１６へ燃料を流すのを停止するものであり、ニードル４２の上昇速度（ニードル背圧室１４の降圧速度）を遅くし、ニードル４２の下降速度（ニードル背圧室１４の昇圧速度）を速める手段である。 A nozzle back pressure chamber 14 for generating a downward force (sitting direction) on the needle 42 by the pressure of the fuel is formed at the upper portion of the needle sliding portion. The nozzle back pressure chamber 14 is formed in a space surrounded by the upper surface of the needle sliding portion, the injector body 21 and the nozzle holder 41. The nozzle back pressure chamber 14 is connected to the differential pressure chamber 16 of the pressure intensifier 17 via the fuel passage 46. The fuel passage 46 is provided with an orifice 46a for reducing the flow passage area and a one-way valve 46b in parallel with the orifice 46a.
This one-way valve 46b stops the flow of fuel from the differential pressure chamber 16 to the nozzle back pressure chamber 14, and conversely stops the flow of fuel from the nozzle back pressure chamber 14 to the differential pressure chamber 16. This is a means for slowing down the speed (pressure reduction speed of the needle back pressure chamber 14) and increasing the descending speed of the needle 42 (pressure increase speed of the needle back pressure chamber 14).

ノズル背圧室１４が連通する差圧室１６の内圧は、上述したように、差圧切替弁１２によって高圧または低圧に切り替えられる。即ち、噴射ノズル１５のノズル背圧室１４は、差圧室１６を介して差圧切替弁１２により内圧が切り替わる。
このため、差圧切替弁１２の「低圧切替（電磁弁１３のＯＮ）」により差圧室１６の内圧が低下すると、差圧室１６を介してノズル背圧室１４の内圧も低下する。ニードル４２の下向き（着座方向）の力より、ニードル４２の上向き（離座方向）の力が上回ると、ニードル４２がリフトして燃料溜４４に供給された高圧燃料が噴孔４３から噴射される。
逆に、差圧切替弁１２の「高圧切替（電磁弁１３のＯＦＦ）」により差圧室１６の内圧が上昇すると、差圧室１６を介してノズル背圧室１４の内圧も上昇する。ニードル４２の下向き（着座方向）の力が、ニードル４２の上向き（離座方向）の力より上回ると、ニードル４２が下降する。そして、ニードル４２がノズルホルダ４１に着座することで噴孔４３からの燃料噴射が停止される。 As described above, the internal pressure of the differential pressure chamber 16 that communicates with the nozzle back pressure chamber 14 is switched between high pressure and low pressure by the differential pressure switching valve 12. That is, the internal pressure of the nozzle back pressure chamber 14 of the injection nozzle 15 is switched by the differential pressure switching valve 12 via the differential pressure chamber 16.
For this reason, when the internal pressure of the differential pressure chamber 16 decreases due to “low pressure switching (electromagnetic valve 13 ON)” of the differential pressure switching valve 12, the internal pressure of the nozzle back pressure chamber 14 also decreases via the differential pressure chamber 16. When the upward force (seating direction) of the needle 42 exceeds the downward force (seating direction) of the needle 42, the needle 42 is lifted and high pressure fuel supplied to the fuel reservoir 44 is injected from the injection hole 43. .
Conversely, when the internal pressure of the differential pressure chamber 16 rises due to “high pressure switching (electromagnetic valve 13 OFF)” of the differential pressure switching valve 12, the internal pressure of the nozzle back pressure chamber 14 also rises via the differential pressure chamber 16. When the downward force (seating direction) of the needle 42 exceeds the upward force (seating direction) of the needle 42, the needle 42 is lowered. Then, when the needle 42 is seated on the nozzle holder 41, fuel injection from the nozzle hole 43 is stopped.

（増圧器１７の説明）
増圧器１７は、等圧室２３に対する差圧室１６の圧力低下により下方へ変位する増圧ピストン５１と、この増圧ピストン５１を初期位置（上方）へ戻すリターンスプリング５２とを備える。
増圧ピストン５１は、インジェクタボディ２１の内部で上下方向に摺動自在に支持される。この増圧ピストン５１には、上方より下方へ向けて、バネ座、バネ収容軸、大径部および小径部が設けられている。
バネ座およびバネ収容軸は、コモンレール１より高圧燃料を受ける等圧室２３内に配置されるものであり、この等圧室２３は常にレール圧に保たれる。等圧室２３の高圧燃料は、増圧ピストン５１の上側の径差に作用して、増圧ピストン５１に下向き（増圧方向）の力を発生させる。
バネ座は、増圧ピストン５１を上方（初期位置復帰方向）へ付勢するリターンスプリング５２の着座部である。リターンスプリング５２は、復元力によりバネ座を上方へ付勢する圧縮コイルスプリングである。 (Description of pressure booster 17)
The pressure booster 17 includes a pressure increasing piston 51 that is displaced downward due to a pressure drop of the differential pressure chamber 16 with respect to the equal pressure chamber 23, and a return spring 52 that returns the pressure increasing piston 51 to an initial position (upward).
The pressure-increasing piston 51 is slidably supported in the vertical direction inside the injector body 21. The pressure increasing piston 51 is provided with a spring seat, a spring accommodating shaft, a large diameter portion, and a small diameter portion from above to below.
The spring seat and the spring housing shaft are disposed in the isobaric chamber 23 that receives high-pressure fuel from the common rail 1, and the isobaric chamber 23 is always kept at the rail pressure. The high-pressure fuel in the isobaric chamber 23 acts on the diameter difference on the upper side of the pressure-increasing piston 51 to generate a downward force (in the pressure-increasing direction) on the pressure-increasing piston 51.
The spring seat is a seating portion of a return spring 52 that urges the pressure-increasing piston 51 upward (in the initial position return direction). The return spring 52 is a compression coil spring that urges the spring seat upward by a restoring force.

大径部および小径部は、ともにインジェクタボディ２１に摺動自在に支持されるものであり、大径部と小径部の段差と、インジェクタボディ２１との間に差圧室１６が形成される。
また、小径部の下面と、インジェクタボディ２１との間には、増圧ピストン５１の上下変位によって容積が変化し、増圧ピストン５１の下降によって燃料の加圧が行われる増圧室５３が形成されている。
この増圧室５３は、等圧室２３から増圧室５３のみに燃料を流す一方向弁５４ａを備えた燃料通路５４を介して等圧室２３に連通している。このため、増圧ピストン５１が停止状態および初期位置へ戻る上昇中は増圧室５３および噴射ノズル１５の燃料溜４４の燃料圧力がレール圧に維持され、増圧ピストン５１が下降すると増圧室５３の内圧が高まり、増圧室５３および燃料溜４４の燃料圧力がレール圧より高まる。 Both the large diameter portion and the small diameter portion are slidably supported by the injector body 21, and a differential pressure chamber 16 is formed between the step between the large diameter portion and the small diameter portion and the injector body 21.
Further, between the lower surface of the small diameter portion and the injector body 21, a pressure increasing chamber 53 is formed in which the volume is changed by the vertical displacement of the pressure increasing piston 51 and fuel is pressurized by the lowering of the pressure increasing piston 51. Has been.
The pressure increasing chamber 53 communicates with the equal pressure chamber 23 via a fuel passage 54 having a one-way valve 54 a that allows fuel to flow from the equal pressure chamber 23 only to the pressure increasing chamber 53. Therefore, the fuel pressure in the pressure increasing chamber 53 and the fuel reservoir 44 of the injection nozzle 15 is maintained at the rail pressure while the pressure increasing piston 51 is in the stopped state and rising to the initial position, and when the pressure increasing piston 51 is lowered, the pressure increasing chamber is increased. The internal pressure of 53 increases, and the fuel pressure in the pressure increasing chamber 53 and the fuel reservoir 44 becomes higher than the rail pressure.

差圧室１６の内圧は、上述したように、差圧切替弁１２によって高圧または低圧に切り替えられる。
このため、差圧切替弁１２の「低圧切替（電磁弁１３のＯＮ）」により差圧室１６が低圧側へ切り替わると、増圧ピストン５１の上向き（初期位置復帰方向）の力より、増圧ピストン５１の下向き（増圧方向）の力が上回り、増圧ピストン５１が下降して増圧室５３の容積が減少し、増圧室５３および噴射ノズル１５の燃料溜４４の燃料圧力がレール圧より高まる。
逆に、差圧切替弁１２の「高圧切替（電磁弁１３のＯＦＦ）」により差圧室１６が高圧側へ切り替わると、増圧ピストン５１の上向き（初期位置復帰方向）の力が、増圧ピストン５１の下向き（増圧方向）の力より上回り、増圧ピストン５１が上昇して増圧ピストン５１が初期位置（上側）に復帰する。 As described above, the internal pressure of the differential pressure chamber 16 is switched between high pressure and low pressure by the differential pressure switching valve 12.
For this reason, when the differential pressure chamber 16 is switched to the low pressure side by “low pressure switching (electromagnetic valve 13 ON)” of the differential pressure switching valve 12, the pressure is increased by the upward force of the pressure increasing piston 51 (initial position return direction). The downward force (pressure increasing direction) of the piston 51 is increased, the pressure increasing piston 51 is lowered, the volume of the pressure increasing chamber 53 is reduced, and the fuel pressure in the fuel reservoir 44 of the pressure increasing chamber 53 and the injection nozzle 15 is the rail pressure. Increase more.
On the other hand, when the differential pressure chamber 16 is switched to the high pressure side by “high pressure switching (electromagnetic valve 13 OFF)” of the differential pressure switching valve 12, the upward force of the pressure increasing piston 51 (initial position return direction) is increased. It exceeds the downward force (pressure increasing direction) of the piston 51, the pressure increasing piston 51 rises, and the pressure increasing piston 51 returns to the initial position (upper side).

〔実施例１の特徴〕
上記参考例で示した燃料噴射装置における差圧切替弁１２は、１つの切替可動弁２２に設けられた上部弁体と下部弁体の変位に基づき、差圧室１６に通じる弁室を、低圧燃料通路２７または高圧燃料通路２８の一方に切り替える。
このため、上記で示した差圧切替弁１２は、差圧室１６を高圧状態から低圧側へ切り替える際の切替途中と、差圧室１６を低圧状態から高圧側へ切り替える際の切替途中とにおいて、上部弁体と下部弁体とが、共にインジェクタボディ２１から離座した状態になり、高圧燃料通路２８と低圧燃料通路２７が弁室を介して連通した状態になる。
このため、コモンレール１から供給された高圧燃料が、高圧燃料通路２８→弁室→低圧燃料通路２７の経路で流出してしまう。この結果、インジェクタ２の高圧燃料の圧力が下がるとともに、サプライポンプのポンプ損失が大きくなってしまう。 [Features of Example 1]
The differential pressure switching valve 12 in the fuel injection device shown in the reference example described above is configured such that the valve chamber leading to the differential pressure chamber 16 is reduced in pressure based on the displacement of the upper valve body and the lower valve body provided in one switching movable valve 22. Switching to one of the fuel passage 27 and the high-pressure fuel passage 28 is performed.
Therefore, the differential pressure switching valve 12 shown above is in the middle of switching when the differential pressure chamber 16 is switched from the high pressure state to the low pressure side, and in the middle of switching when the differential pressure chamber 16 is switched from the low pressure state to the high pressure side. The upper valve body and the lower valve body are both separated from the injector body 21, and the high-pressure fuel passage 28 and the low-pressure fuel passage 27 are in communication with each other via the valve chamber.
For this reason, the high-pressure fuel supplied from the common rail 1 flows out through the path of the high-pressure fuel passage 28 → the valve chamber → the low-pressure fuel passage 27. As a result, the pressure of the high-pressure fuel in the injector 2 decreases and the pump loss of the supply pump increases.

そこでこの実施例１では、上記の問題点を解決すべく本発明を採用している。
この実施例１のインジェクタ２は、本発明を採用するため、高圧燃料と低圧燃料が切り替えられる差圧室１６を有し、この差圧室１６が高圧燃料または低圧燃料に切り替えられることで作動する増圧器１７（作動器の一例）と、高圧燃料が供給される切替弁背圧室１１の油圧変化により、差圧室１６の圧力を高圧燃料または低圧燃料に切り替える差圧切替弁１２と、切替弁背圧室１１と低圧側との連通または遮断を行い、切替弁背圧室１１を高圧燃料または低圧燃料に切り替える電磁弁１３（電動アクチュエータ弁の一例）とを具備する。 Therefore, in the first embodiment, the present invention is adopted to solve the above problems.
In order to employ the present invention, the injector 2 of the first embodiment has a differential pressure chamber 16 in which high pressure fuel and low pressure fuel are switched, and operates by switching the differential pressure chamber 16 to high pressure fuel or low pressure fuel. Switching between a pressure intensifier 17 (an example of an actuator) and a differential pressure switching valve 12 for switching the pressure in the differential pressure chamber 16 to high pressure fuel or low pressure fuel by changing the hydraulic pressure in the switching valve back pressure chamber 11 to which high pressure fuel is supplied. An electromagnetic valve 13 (an example of an electric actuator valve) that communicates or shuts off the valve back pressure chamber 11 and the low pressure side and switches the switching valve back pressure chamber 11 to high pressure fuel or low pressure fuel is provided.

そして、この実施例１の差圧切替弁１２は、
切替弁背圧室１１の油圧変化により、差圧室１６と高圧側との連通を行う高圧燃料通路２８の開閉を行う高圧切替弁６１と、
切替弁背圧室１１の油圧変化により、差圧室１６と低圧側との連通を行う低圧燃料通路２７の開閉を行う低圧切替弁６２とを備えるものであり、
切替弁背圧室１１の油圧変化により、差圧室１６を低圧側に切り替える際に、
先ず、高圧切替弁６１が高圧燃料通路２８を閉じ、
次に、低圧切替弁６２が低圧燃料通路２７を開くように設けられるとともに、
切替弁背圧室１１の油圧変化により、差圧室１６を高圧側に切り替える際に、
先ず、低圧切替弁６２が低圧燃料通路２７を閉じ、
次に、高圧切替弁６１が高圧燃料通路２８を開くように設けられている。
具体的に、この実施例１の差圧切替弁１２は、高圧切替弁６１において高圧燃料通路２８の開閉を行う第１可動弁６３と、低圧切替弁６２において低圧燃料通路２７の開閉を行う第２可動弁６４とが、独立して可動する独立弁体を採用している。 The differential pressure switching valve 12 of the first embodiment is
A high-pressure switching valve 61 that opens and closes the high-pressure fuel passage 28 that communicates between the differential pressure chamber 16 and the high-pressure side due to a change in hydraulic pressure of the switching valve back pressure chamber 11;
A low-pressure switching valve 62 that opens and closes the low-pressure fuel passage 27 that communicates between the differential pressure chamber 16 and the low-pressure side due to a change in the hydraulic pressure of the switching valve back-pressure chamber 11;
When the differential pressure chamber 16 is switched to the low pressure side due to the hydraulic pressure change of the switching valve back pressure chamber 11,
First, the high pressure switching valve 61 closes the high pressure fuel passage 28,
Next, a low pressure switching valve 62 is provided to open the low pressure fuel passage 27, and
When the differential pressure chamber 16 is switched to the high pressure side due to the hydraulic pressure change of the switching valve back pressure chamber 11,
First, the low pressure switching valve 62 closes the low pressure fuel passage 27,
Next, a high pressure switching valve 61 is provided to open the high pressure fuel passage 28.
Specifically, the differential pressure switching valve 12 of the first embodiment includes a first movable valve 63 that opens and closes the high pressure fuel passage 28 in the high pressure switching valve 61 and a first movable valve 63 that opens and closes the low pressure fuel passage 27 in the low pressure switching valve 62. The 2 movable valve 64 employs an independent valve body that can move independently.

（高圧切替弁６１の説明）
第１可動弁６３の上部には、インジェクタボディ２１の上下方向に摺動自在に支持される第１摺動ピストンが設けられている。この第１ピストンの上面と、インジェクタボディ２１に囲まれる空間によって、第１高圧室６５が形成されている。この第１高圧室６５は、等圧室２３と高圧燃料通路２４を介して連通しており、第１可動弁６３に閉弁方向（下方）に向かう付勢力を与える。
なお、この実施例１の第１高圧室６５は、低圧切替弁６２において後述する第２高圧室７１と、高圧連通路２４’を介して連通するものである。 (Description of high pressure switching valve 61)
A first sliding piston that is slidably supported in the vertical direction of the injector body 21 is provided on the upper portion of the first movable valve 63. A first high pressure chamber 65 is formed by the upper surface of the first piston and a space surrounded by the injector body 21. The first high pressure chamber 65 communicates with the isobaric chamber 23 via the high pressure fuel passage 24, and applies a biasing force toward the valve closing direction (downward) to the first movable valve 63.
The first high pressure chamber 65 of the first embodiment communicates with a second high pressure chamber 71 described later in the low pressure switching valve 62 via the high pressure communication path 24 ′.

第１可動弁６３の下部には、第１摺動ピストンより小径の第１開閉弁体が設けられている。この第１開閉弁体は、高圧燃料通路２８の上端開口部（弁開口）を開閉するものであり、上方へ変位して第１開閉弁体の下端面がインジェクタボディ２１から離座すると、高圧燃料通路２８と燃料通路２６とが高圧切替弁６１の下部に形成される第１弁室を介して連通し（高圧燃料通路２８を開く）、下方へ変位して第１開閉弁体の下端面がインジェクタボディ２１に着座すると、第１開閉弁体が高圧燃料通路２８と燃料通路２６との連通を遮断する（高圧燃料通路２８を閉じる）。
なお、第１弁室は、低圧切替弁６２において後述する第２弁室と、燃料通路６６を介して連通するものである。 A first opening / closing valve body having a smaller diameter than the first sliding piston is provided below the first movable valve 63. The first on-off valve body opens and closes the upper end opening (valve opening) of the high-pressure fuel passage 28. When the first on-off valve body is displaced upward and the lower end surface of the first on-off valve body is separated from the injector body 21, the high pressure is opened. The fuel passage 28 and the fuel passage 26 communicate with each other via a first valve chamber formed in the lower portion of the high-pressure switching valve 61 (opens the high-pressure fuel passage 28), and is displaced downward to be the lower end surface of the first on-off valve body. Is seated on the injector body 21, the first on-off valve body cuts off the communication between the high pressure fuel passage 28 and the fuel passage 26 (closes the high pressure fuel passage 28).
The first valve chamber communicates with a second valve chamber, which will be described later, in the low pressure switching valve 62 via the fuel passage 66.

また、高圧切替弁６１は、第１可動弁６３の他に、第１可動弁６３が高圧燃料通路２８を開く方向（上方）に第１可動弁６３を付勢する第１リターンスプリング６７を備える。この第１リターンスプリング６７は、第１摺動ピストンと第１開閉弁体との段差の下面に当接して、第１可動弁６３を上方に付勢する圧縮コイルスプリングである。
この第１リターンスプリング６７が配置される第１スプリング室は、高圧切替弁６１における切替弁背圧室１１であり、電磁弁１３が閉じられた状態（ＯＦＦ）では、入口オリフィス２４ａを介して高圧連通路２４’から高圧燃料が供給され、第１リターンスプリング６７の付勢力とともに、第１可動弁６３を上方へ変位させる。逆に、電磁弁１３が開かれた状態（ＯＮ）では、第１スプリング室（高圧切替弁６１における切替弁背圧室１１）は低圧燃料通路２５を介して排圧され、第１高圧室６５による付勢力によって第１可動弁６３を下方へ変位させる。 In addition to the first movable valve 63, the high-pressure switching valve 61 includes a first return spring 67 that urges the first movable valve 63 in the direction (upward) in which the first movable valve 63 opens the high-pressure fuel passage 28. . The first return spring 67 is a compression coil spring that abuts the lower surface of the step between the first sliding piston and the first on-off valve body and biases the first movable valve 63 upward.
The first spring chamber in which the first return spring 67 is disposed is the switching valve back pressure chamber 11 in the high pressure switching valve 61. When the electromagnetic valve 13 is closed (OFF), the first return spring 67 has a high pressure via the inlet orifice 24a. High pressure fuel is supplied from the communication path 24 ′, and the first movable valve 63 is displaced upward together with the urging force of the first return spring 67. Conversely, when the electromagnetic valve 13 is opened (ON), the first spring chamber (the switching valve back pressure chamber 11 in the high pressure switching valve 61) is exhausted via the low pressure fuel passage 25, and the first high pressure chamber 65 is discharged. The first movable valve 63 is displaced downward by the urging force of.

（低圧切替弁６２の説明）
第２可動弁６４の上部には、インジェクタボディ２１の上下方向に摺動自在に支持される第２摺動ピストンが設けられ、第２可動弁６４の下部には、第２摺動ピストンより小径の第２開閉弁体が設けられている。第２摺動ピストンと第２開閉弁体との段差の下面と、インジェクタボディ２１に囲まれる空間によって、第２高圧室７１が形成されている。この第２高圧室７１は、等圧室２３と高圧燃料通路２４を介して連通しており、第２可動弁６４に開弁方向（上方）に向かう付勢力を与える。 (Description of the low pressure switching valve 62)
A second sliding piston that is slidably supported in the vertical direction of the injector body 21 is provided on the upper part of the second movable valve 64, and has a smaller diameter than the second sliding piston on the lower part of the second movable valve 64. The second on-off valve body is provided. A second high pressure chamber 71 is formed by the lower surface of the step between the second sliding piston and the second on-off valve body and the space surrounded by the injector body 21. The second high-pressure chamber 71 communicates with the isobaric chamber 23 via the high-pressure fuel passage 24 and applies a biasing force toward the valve opening direction (upward) to the second movable valve 64.

第２可動弁６４の下部の第２開閉弁体は、低圧燃料通路２７の上端開口部（弁開口）を開閉するものであり、上方へ変位して第２開閉弁体の下端面がインジェクタボディ２１から離座すると、低圧燃料通路２７と燃料通路２６とが低圧切替弁６２の下部に形成される第２弁室を介して連通し（低圧燃料通路２７を開く）、下方へ変位して第２開閉弁体の下端面がインジェクタボディ２１に着座すると第２開閉弁体が低圧燃料通路２７と燃料通路２６との連通を遮断する（低圧燃料通路２７を閉じる）。
なお、第２弁室は、上述したように燃料通路６６を介して高圧切替弁６１の第１弁室と連通するものであり、第２可動弁６４が上昇して低圧燃料通路２７が開かれると、低圧燃料通路２７は、第２弁室、燃料通路６６、第１弁室を介して燃料通路２６に連通するものである。 The second opening / closing valve body below the second movable valve 64 opens and closes the upper end opening (valve opening) of the low pressure fuel passage 27, and is displaced upward so that the lower end surface of the second opening / closing valve body is the injector body. When separated from the valve 21, the low-pressure fuel passage 27 and the fuel passage 26 communicate with each other through the second valve chamber formed in the lower portion of the low-pressure switching valve 62 (opens the low-pressure fuel passage 27), and is displaced downward. When the lower end surface of the two on-off valve body is seated on the injector body 21, the second on-off valve body cuts off the communication between the low pressure fuel passage 27 and the fuel passage 26 (closes the low pressure fuel passage 27).
The second valve chamber communicates with the first valve chamber of the high pressure switching valve 61 through the fuel passage 66 as described above, and the second movable valve 64 is raised to open the low pressure fuel passage 27. The low-pressure fuel passage 27 communicates with the fuel passage 26 via the second valve chamber, the fuel passage 66, and the first valve chamber.

低圧切替弁６２は、第２可動弁６４の他に、第２可動弁６４が低圧燃料通路２７を閉じる方向（下方）に、第２可動弁６４を付勢する第２リターンスプリング７２を備える。
第２リターンスプリング７２は、第２摺動ピストンの上面に当接して、第２可動弁６４を下方に付勢する圧縮コイルスプリングである。
この第２リターンスプリング７２が配置される第２スプリング室は、低圧切替弁６２における切替弁背圧室１１であり、電磁弁１３が閉じられた状態（ＯＦＦ）では、入口オリフィス２４ａを介して高圧連通路２４’から高圧燃料が供給され、第２リターンスプリング７２の付勢力とともに、第２可動弁６４を下方へ変位させる。逆に、電磁弁１３が開かれた状態（ＯＮ）では、第２スプリング室（低圧切替弁６２における切替弁背圧室１１）は低圧燃料通路２５を介して排圧され、第２高圧室７１による付勢力によって第２可動弁６４を上方へ変位させる。 In addition to the second movable valve 64, the low pressure switching valve 62 includes a second return spring 72 that urges the second movable valve 64 in a direction (downward) in which the second movable valve 64 closes the low pressure fuel passage 27.
The second return spring 72 is a compression coil spring that abuts on the upper surface of the second sliding piston and biases the second movable valve 64 downward.
The second spring chamber in which the second return spring 72 is disposed is the switching valve back pressure chamber 11 in the low pressure switching valve 62, and when the electromagnetic valve 13 is closed (OFF), the high pressure via the inlet orifice 24a. High pressure fuel is supplied from the communication path 24 ′, and the second movable valve 64 is displaced downward together with the urging force of the second return spring 72. On the contrary, in a state where the electromagnetic valve 13 is opened (ON), the second spring chamber (the switching valve back pressure chamber 11 in the low pressure switching valve 62) is discharged through the low pressure fuel passage 25, and the second high pressure chamber 71 is discharged. The second movable valve 64 is displaced upward by the urging force of.

（高圧切替弁６１と低圧切替弁６２とが差動する説明）
この実施例１では、第１可動弁６３における第１摺動ピストンおよび第１開閉弁体の径が、第２可動弁６４における第２摺動ピストンおよび第２開閉弁体の径と略同じに設けられている。
このため、第１高圧室６５の圧力によって第１可動弁６３の受ける閉弁力が、第２高圧室７１の圧力によって第２可動弁６４の受ける開弁力より上回るため、第１、第２リターンスプリング６７、７２の付勢力が同じであっても、上述したように、差圧室１６を低圧側に切り替える際に、先ず高圧切替弁６１が高圧燃料通路２８を閉じ、次に低圧切替弁６２が低圧燃料通路２７を開く作動を行うとともに、差圧室１６を高圧側に切り替える際に、先ず低圧切替弁６２が低圧燃料通路２７を閉じ、次に高圧切替弁６１が高圧燃料通路２８を開く作動を行う。
なお、高圧切替弁６１と低圧切替弁６２の差動時期は、第１、第２可動弁６３、６４における第１、第２摺動ピストンと第１、第２開閉弁体の径差や、第１、第２リターンスプリング６７、７２の付勢力の差によって調整することができる。 (Explanation that the high pressure switching valve 61 and the low pressure switching valve 62 are differential)
In the first embodiment, the diameters of the first sliding piston and the first on-off valve body in the first movable valve 63 are substantially the same as the diameters of the second sliding piston and the second on-off valve body in the second movable valve 64. Is provided.
For this reason, the valve closing force received by the first movable valve 63 due to the pressure of the first high pressure chamber 65 exceeds the valve opening force received by the second movable valve 64 due to the pressure of the second high pressure chamber 71. Even when the urging forces of the return springs 67 and 72 are the same, as described above, when the differential pressure chamber 16 is switched to the low pressure side, the high pressure switching valve 61 first closes the high pressure fuel passage 28 and then the low pressure switching valve. 62 opens the low-pressure fuel passage 27 and when the differential pressure chamber 16 is switched to the high-pressure side, the low-pressure switching valve 62 first closes the low-pressure fuel passage 27, and then the high-pressure switching valve 61 opens the high-pressure fuel passage 28. Opening operation is performed.
The differential timing of the high pressure switching valve 61 and the low pressure switching valve 62 is the difference in diameter between the first and second sliding pistons and the first and second on-off valve bodies in the first and second movable valves 63 and 64, It can be adjusted by the difference between the urging forces of the first and second return springs 67 and 72.

（実施例１の効果）
この実施例１のインジェクタ２は、電磁弁１３をＯＮして差圧室１６を低圧側に切り替える際に、先ず、高圧切替弁６１が高圧燃料通路２８を閉じ、次に、低圧切替弁６２が低圧燃料通路２７を開く作動を行う。また、電磁弁１３がＯＦＦして差圧室１６を高圧側に切り替える際に、先ず、低圧切替弁６２が低圧燃料通路２７を閉じ、次に、高圧切替弁６１が高圧燃料通路２８を開く作動を行う。
このように、差圧切替弁１２が切り替わる際、切替途中に高圧燃料通路２８と低圧燃料通路２７とが同時に開くことがなく、高圧燃料通路２８と低圧燃料通路２７とが差圧切替弁１２を介して連通することがない。
このため、差圧切替弁１２の切替途中に高圧燃料通路２８の高圧燃料が、高圧燃料通路２８→差圧切替弁１２→低圧燃料通路２７の経路で流出する不具合がなく、インジェクタ２に供給される高圧燃料の圧力の低下を防ぐことができるとともに、サプライポンプのポンプ損失が大きくなる不具合を回避できる。 (Effect of Example 1)
In the injector 2 of the first embodiment, when the electromagnetic valve 13 is turned on to switch the differential pressure chamber 16 to the low pressure side, first, the high pressure switching valve 61 closes the high pressure fuel passage 28, and then the low pressure switching valve 62 The operation of opening the low-pressure fuel passage 27 is performed. When the electromagnetic valve 13 is turned off and the differential pressure chamber 16 is switched to the high pressure side, the low pressure switching valve 62 first closes the low pressure fuel passage 27 and then the high pressure switching valve 61 opens the high pressure fuel passage 28. I do.
Thus, when the differential pressure switching valve 12 is switched, the high pressure fuel passage 28 and the low pressure fuel passage 27 do not open simultaneously during switching, and the high pressure fuel passage 28 and the low pressure fuel passage 27 connect the differential pressure switching valve 12. There is no communication through.
Therefore, there is no problem that the high-pressure fuel in the high-pressure fuel passage 28 flows out through the high-pressure fuel passage 28 → the differential-pressure switching valve 12 → the low-pressure fuel passage 27 during the switching of the differential pressure switching valve 12 and is supplied to the injector 2. The pressure drop of the high-pressure fuel can be prevented, and the problem that the pump loss of the supply pump becomes large can be avoided.

〔変形例〕
上記の実施例では、電動アクチュエータ弁の一例として電磁弁１３を示したが、アクチュエータにピエゾを多数スタックしたピエゾスタックを用いるなど、他の電動アクチュエータ弁を用いても良い。
上記の実施例では、作動器の一例として増圧器１７を示したが、高圧燃料と低圧燃料が切り替えられる差圧室１６を有し、差圧室１６が高圧燃料または低圧燃料に切り替えられることで作動する作動器を備えるインジェクタであれば、本発明を適用することができる。 [Modification]
In the above embodiment, the electromagnetic valve 13 is shown as an example of the electric actuator valve. However, other electric actuator valves may be used, such as a piezo stack in which a large number of piezos are stacked on the actuator.
In the above embodiment, the pressure intensifier 17 is shown as an example of the actuator. However, the pressure intensifier 17 has the differential pressure chamber 16 in which high pressure fuel and low pressure fuel can be switched, and the differential pressure chamber 16 is switched to high pressure fuel or low pressure fuel. The present invention can be applied to any injector provided with an operating actuator.

燃料噴射装置の概略図である（参考例と実施例１）。 It is the schematic of a fuel-injection apparatus (reference example and Example 1 ).

Explanation of symbols

２インジェクタ
１１切替弁背圧室
１２差圧切替弁
１３電磁弁（電動アクチュエータ弁）
１５噴射ノズル
１６差圧室
１７増圧器（作動器）
２７低圧燃料通路
２８高圧燃料通路
４４燃料溜
５１増圧ピストン
６１高圧切替弁
６２低圧切替弁
６３第１可動弁
６４第２可動弁
６５第１高圧室
６７第１リターンスプリング
７１第２高圧室
７２第２リターンスプリング 2 Injector 11 Switching valve back pressure chamber 12 Differential pressure switching valve 13 Electromagnetic valve (electric actuator valve)
15 Injection nozzle 16 Differential pressure chamber 17 Booster (actuator)
27 Low pressure fuel passage 28 High pressure fuel passage 44 Fuel reservoir 51 Boosting piston 61 High pressure switching valve 62 Low pressure switching valve 63 First movable valve 64 Second movable valve 65 First high pressure chamber 67 First return spring 71 Second high pressure chamber 72 First 2 return spring

Claims

An actuator having a differential pressure chamber in which high pressure fuel and low pressure fuel can be switched, and operating by switching the differential pressure chamber to high pressure fuel or low pressure fuel;
A differential pressure switching valve that switches the pressure in the differential pressure chamber to high pressure fuel or low pressure fuel according to a change in hydraulic pressure of the switching valve back pressure chamber to which high pressure fuel is supplied;
An electric actuator valve that communicates or shuts off the switching valve back pressure chamber and the low pressure side, and switches the switching valve back pressure chamber to high pressure fuel or low pressure fuel;
In an injector comprising
The differential pressure switching valve is
A high-pressure switching valve that opens and closes a high-pressure fuel passage that communicates between the differential pressure chamber and the high-pressure side due to a change in hydraulic pressure of the switching valve back pressure chamber;
A low-pressure switching valve that opens and closes a low-pressure fuel passage that communicates between the differential pressure chamber and the low-pressure side due to a change in hydraulic pressure of the switching valve back-pressure chamber;
When switching the differential pressure chamber to the low pressure side due to a change in hydraulic pressure of the switching valve back pressure chamber,
First, the high pressure switching valve closes the high pressure fuel passage,
Next, the low-pressure switching valve opens the low-pressure fuel passage,
When switching the differential pressure chamber to the high pressure side due to a change in the hydraulic pressure of the switching valve back pressure chamber,
First, the low pressure switching valve closes the low pressure fuel passage,
Next, the high-pressure switching valve opens the high-pressure fuel passage ,
A first movable valve that opens and closes the high-pressure fuel passage in the high-pressure switching valve;
The second movable valve that opens and closes the low-pressure fuel passage in the low-pressure switching valve,
It is an independent valve body that can move independently ,
In addition to the first movable valve, the high-pressure switching valve is
A first return spring that biases the first movable valve in a direction in which the first movable valve opens the high-pressure fuel passage;
A first high pressure chamber for biasing the first movable valve in a direction in which the first movable valve closes the high pressure fuel passage;
The injector, wherein the switching valve back pressure chamber in the high pressure switching valve is formed in a first spring chamber in which the first return spring is disposed.

An actuator having a differential pressure chamber in which high pressure fuel and low pressure fuel can be switched, and operating by switching the differential pressure chamber to high pressure fuel or low pressure fuel;
A differential pressure switching valve that switches the pressure in the differential pressure chamber to high pressure fuel or low pressure fuel according to a change in hydraulic pressure of the switching valve back pressure chamber to which high pressure fuel is supplied;
An electric actuator valve that communicates or shuts off the switching valve back pressure chamber and the low pressure side, and switches the switching valve back pressure chamber to high pressure fuel or low pressure fuel;
In an injector comprising
The differential pressure switching valve is
A high-pressure switching valve that opens and closes a high-pressure fuel passage that communicates between the differential pressure chamber and the high-pressure side due to a change in hydraulic pressure of the switching valve back pressure chamber;
A low-pressure switching valve that opens and closes a low-pressure fuel passage that communicates between the differential pressure chamber and the low-pressure side due to a change in hydraulic pressure of the switching valve back-pressure chamber;
When switching the differential pressure chamber to the low pressure side due to a change in hydraulic pressure of the switching valve back pressure chamber,
First, the high pressure switching valve closes the high pressure fuel passage,
Next, the low-pressure switching valve opens the low-pressure fuel passage,
When switching the differential pressure chamber to the high pressure side due to a change in the hydraulic pressure of the switching valve back pressure chamber,
First, the low pressure switching valve closes the low pressure fuel passage,
Next, the high-pressure switching valve opens the high-pressure fuel passage ,
A first movable valve that opens and closes the high-pressure fuel passage in the high-pressure switching valve;
The second movable valve that opens and closes the low-pressure fuel passage in the low-pressure switching valve,
It is an independent valve body that can move independently ,
In addition to the second movable valve, the low-pressure switching valve is
A second return spring that biases the second movable valve in a direction in which the second movable valve closes the low-pressure fuel passage;
A second high pressure chamber for biasing the second movable valve in a direction in which the second movable valve opens the low pressure fuel passage;
The injector, wherein the switching valve back pressure chamber in the low pressure switching valve is formed in a second spring chamber in which the second return spring is disposed.

Injector according to claim 1 or claim 2 ,
The injector includes a fuel reservoir to which high-pressure fuel is supplied, and includes an injection nozzle that performs an operation of injecting and stopping the fuel in the fuel reservoir.
The actuator is a pressure intensifier including a pressure increasing piston that is displaced by switching the differential pressure chamber to high pressure fuel or low pressure fuel,
The injector is characterized in that the pressure-increasing piston performs a pressure-increasing operation of the high-pressure fuel in the fuel reservoir by the displacement of the differential pressure chamber being switched from high-pressure fuel to low-pressure fuel.