Fuel injector with direct needle control for an internal combustion engine
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F02M-047/02
B05B-001/30
B05B-001/08
B05B-001/02
출원번호
US-0344099
(2006-02-01)
등록번호
US-7419103
(2008-09-02)
우선권정보
DE-10 2005 004 738(2005-02-02)
발명자
/ 주소
Pauer,Thomas
출원인 / 주소
Robert Bosch GmbH
대리인 / 주소
Greigg,Ronald E.
인용정보
피인용 횟수 :
8인용 특허 :
5
초록▼
A fuel injector with direct needle control has a nozzle needle guided in a nozzle body, and an actuator and a hydraulic pressure boosting unit that has an actuator pressure boosting piston connected to the actuator and a nozzle needle pressure boosting piston connected to the nozzle needle. The actu
A fuel injector with direct needle control has a nozzle needle guided in a nozzle body, and an actuator and a hydraulic pressure boosting unit that has an actuator pressure boosting piston connected to the actuator and a nozzle needle pressure boosting piston connected to the nozzle needle. The actuator pressure boosting piston and the nozzle needle pressure boosting piston both act on a coupler chamber. The nozzle needle pressure boosting piston contains a cylindrical chamber in which a control piston is axially guided, whose coupler chamber pressure surface is exposed to the coupler chamber and whose differential pressure chamber pressure surface is exposed to an inner differential pressure chamber contained in the cylindrical chamber. At its end oriented away from the coupler chamber, the nozzle needle pressure boosting piston is associated with an outer differential pressure chamber that communicates with the inner differential pressure chamber via a hydraulic connection.
대표청구항▼
I claim: 1. A fuel injector for an internal combustion engine, having a nozzle needle that is guided in a nozzle body and acts on a nozzle needle sealing seat, and having a piezoelectric actuator and a hydraulic pressure boosting unit that has an actuator pressure boosting piston connected to the a
I claim: 1. A fuel injector for an internal combustion engine, having a nozzle needle that is guided in a nozzle body and acts on a nozzle needle sealing seat, and having a piezoelectric actuator and a hydraulic pressure boosting unit that has an actuator pressure boosting piston connected to the actuator and a nozzle needle pressure boosting piston connected to the nozzle needle, both of which pistons act on a coupler chamber located between the actuator pressure boosting piston and the nozzle needle pressure boosting piston and, depending on the pressure in the coupler chamber, the nozzle needle is lifted away from the nozzle needle sealing seat and thus highly pressurized fuel is injected from a high-pressure chamber into a combustion chamber of the engine, the improvement wherein the nozzle needle pressure boosting piston comprises a cylindrical chamber, a control piston axially guided in the cylindrical chamber and having a coupler chamber pressure surface exposed to the coupler chamber and having a differential pressure chamber pressure surface exposed to an inner differential pressure chamber contained in the cylindrical chamber, and the nozzle needle pressure boosting piston being associated with an outer differential pressure chamber that communicates via a hydraulic connection with the inner differential pressure chamber acting on the control piston. 2. The fuel injector according to claim 1, wherein at the end oriented away from the coupler chamber, the outer differential pressure chamber is associated with the nozzle needle pressure boosting piston. 3. The fuel injector according to claim 1, further comprising a guide sleeve, the actuator pressure booster piston and the nozzle needle pressure booster piston being guided in the guide sleeve. 4. The fuel injector according to claim 3, further comprising a plunger spring prestressing the actuator pressure booster piston in the direction opposite from the closing direction of the nozzle needle, the plunger spring being supported against the guide sleeve. 5. A fuel injector for an internal combustion engine, having a nozzle needle that is guided in a nozzle body and acts on a nozzle needle sealing seat, and having a piezoelectric actuator and a hydraulic pressure boosting unit that has an actuator pressure boosting piston connected to the actuator and a nozzle needle pressure boosting piston connected to the nozzle needle, both of which pistons act on a coupler chamber and, depending on the pressure in the coupler chamber, the nozzle needle is lifted away from the nozzle needle sealing seat and thus highly pressurized fuel is injected from a high-pressure chamber into a combustion chamber of the engine, the improvement wherein the nozzle needle pressure boosting piston comprises a cylindrical chamber, a control piston axially guided in the cylindrical chamber and having a coupler chamber pressure surface exposed to the coupler chamber and having a differential pressure chamber pressure surface exposed to an inner differential pressure chamber contained in the cylindrical chamber, and the nozzle needle pressure boosting piston being associated with an outer differential pressure chamber that communicates via a hydraulic connection with the inner differential pressure chamber acting on the control piston, wherein, in a stop position of the control piston, the nozzle needle pressure booster piston and the control piston jointly form a coupler chamber pressure surface facing into the coupler chamber, which pressure surface, together with a third coupler chamber pressure surface embodied on the actuator pressure booster piston and points into the coupler chamber, constitutes a first pressure boosting ratio for a first boosting stage. 6. The fuel injector according to claim 5, further comprising a stop surface establishing the stop position of the control piston in the cylindrical chamber. 7. The fuel injector according to claim 6, further comprising a compression spring prestressing the control piston against the stop surface. 8. The fuel injector according to claim 7, wherein, in a position in which the control piston is lifted away from the stop surface, the first, annular coupler chamber pressure surface pointing from the nozzle needle pressure booster piston into the coupler chamber, in relation to the third coupler chamber pressure surface constituted by the actuator pressure booster piston facing into the coupler chamber, constitutes a second pressure boosting ratio that produces an opening stroke that goes beyond the stroke of the actuator, for a second boosting stage. 9. The fuel injector according to claim 6, wherein, in a position in which the control piston is lifted away from the stop surface, the first, annular coupler chamber pressure surface pointing from the nozzle needle pressure booster piston into the coupler chamber, in relation to the third coupler chamber pressure surface constituted by the actuator pressure booster piston facing into the coupler chamber, constitutes a second pressure boosting ratio that produces an opening stroke that goes beyond the stroke of the actuator, for a second boosting stage. 10. A fuel injector for an internal combustion engine, having a nozzle needle that is guided in a nozzle body and acts on a nozzle needle sealing seat, and having a piezoelectric actuator and a hydraulic pressure boosting unit that has an actuator pressure boosting piston connected to the actuator and a nozzle needle pressure boosting piston connected to the nozzle needle, both of which pistons act on a coupler chamber and, depending on the pressure in the coupler chamber, the nozzle needle is lifted away from the nozzle needle sealing seat and thus highly pressurized fuel is injected from a high-pressure chamber into a combustion chamber of the engine, the improvement wherein the nozzle needle pressure boosting piston comprises a cylindrical chamber, a control piston axially guided in the cylindrical chamber and having a coupler chamber pressure surface exposed to the coupler chamber and having a differential pressure chamber pressure surface exposed to an inner differential pressure chamber contained in the cylindrical chamber, and the nozzle needle pressure boosting piston being associated with an outer differential pressure chamber that communicates via a hydraulic connection with the inner differential pressure chamber acting on the control piston, wherein at the end oriented away from the coupler chamber, the outer differential pressure chamber is associated with the nozzle needle pressure boosting piston, and wherein, in a stop position of the control piston, the nozzle needle pressure booster piston and the control piston jointly form a coupler chamber pressure surface facing into the coupler chamber, which pressure surface, together with a third coupler chamber pressure surface embodied on the actuator pressure booster piston and points into the coupler chamber, constitutes a first pressure boosting ratio for a first boosting stage. 11. The fuel injector according to claim 10, further comprising a stop surface establishing the stop position of the control piston in the cylindrical chamber. 12. The fuel injector according to claim 11, further comprising a compression spring prestressing the control piston against the stop surface. 13. The fuel injector according to claim 12, wherein, in a position in which the control piston is lifted away from the stop surface, the first, annular coupler chamber pressure surface pointing from the nozzle needle pressure booster piston into the coupler chamber, in relation to the third coupler chamber pressure surface constituted by the actuator pressure booster piston facing into the coupler chamber, constitutes a second pressure boosting ratio that produces an opening stroke that goes beyond the stroke of the actuator, for a second boosting stage. 14. The fuel injector according to claim 11, wherein, in a position in which the control piston is lifted away from the stop surface, the first, annular coupler chamber pressure surface pointing from the nozzle needle pressure booster piston into the coupler chamber, in relation to the third coupler chamber pressure surface constituted by the actuator pressure booster piston facing into the coupler chamber, constitutes a second pressure boosting ratio that produces an opening stroke that goes beyond the stroke of the actuator, for a second boosting stage.
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이 특허에 인용된 특허 (5)
Rembold Helmut,DEX ; Haag Gottlob,DEX ; Stutzenberger Heinz,DEX, Fuel injection valve with a piezo-electric or magnetostrictive actuator.
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