Hydraulic valve actuator for actuating a gas-exchange valve
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F01L-009/02
F01L-009/00
출원번호
US-0493858
(2003-03-05)
우선권정보
DE-102 39 747(2002-08-29)
국제출원번호
PCT/DE03/000699
(2003-03-05)
§371/§102 date
20040929
(20040929)
국제공개번호
WO04/022929
(2004-03-18)
발명자
/ 주소
Diehl,Udo
Hammer,Uwe
Mischker,Karsten
출원인 / 주소
Robert Bosch GmbH
대리인 / 주소
Kenyon &
인용정보
피인용 횟수 :
3인용 특허 :
5
초록▼
An hydraulic valve actuator for actuating a gas-exchange valve in a combustion cylinder of an internal combustion engine has an operating piston delimiting two pressure chambers, of which the lower pressure chamber acting in the valve-closing direction is permanently charged with fluid pressure via
An hydraulic valve actuator for actuating a gas-exchange valve in a combustion cylinder of an internal combustion engine has an operating piston delimiting two pressure chambers, of which the lower pressure chamber acting in the valve-closing direction is permanently charged with fluid pressure via which an intake and return line can be charged by, or relieved of, fluid pressure. To brake the gas-exchange valve in the final phase of the closing procedure to reduce the set-down speed, the return line of the upper pressure chamber is split between two discharge openings, which are connected to one another and arranged in the housing with axial clearance, the upper discharge opening being coupled to a restrictor and the lower discharge opening being displaceable relative to the operating piston and disposed in its displacement path such that it may be closed thereby at a defined distance, prior to reaching its upper limit position.
대표청구항▼
The invention claimed is: 1. An hydraulic valve actuator for activating a gas-exchange valve in a combustion cylinder of an internal combustion engine, comprising: a housing; an operating piston accommodated in the housing, the operating piston being axially displaceable within the housing to an up
The invention claimed is: 1. An hydraulic valve actuator for activating a gas-exchange valve in a combustion cylinder of an internal combustion engine, comprising: a housing; an operating piston accommodated in the housing, the operating piston being axially displaceable within the housing to an upper limit position which closes the gas-exchange valve and to a lower limit position which maximally opens the gas-exchange valve; an intake line; a return line having upper and lower discharge openings that are mutually connected and are disposed in the housing with axial clearance; lower and upper variable-volume pressure chambers axially delimited by the operating piston, the lower pressure chamber being delimited by a first effective area of the operating piston and being situated so as to be permanently acted on by fluid pressure, the upper pressure chamber being delimited by a second effective area of the operating piston and situated to enable alternate pressurization and depressurization via the intake line and the return line, the first effective area being smaller than the second effective area; and a restrictor coupled to the upper discharge opening; wherein the lower discharge opening is disposed in the displacement path of the operating piston such that the lower discharge opening is closed by the operating piston before the operating piston reaches the upper limit position, and wherein the lower discharge opening is axially displaceable relative to the operating piston. 2. The hydraulic valve actuator of claim 1, further comprising: a compensating piston enclosing the operating piston and displaceable relative to the operating piston, the compensating piston being configured to be carried along by the operating piston as the operating piston moves into the upper limit position; and a sealable compensating chamber; wherein the lower discharge opening has a first radial bore penetrating the housing, and a second radial bore communicating with the first radial bore is positioned in the compensating piston; and wherein the compensating piston, together with the operating piston, axially delimits the upper pressure chamber in the housing on a first end of the compensating piston, and axially delimits the sealable compensating chamber on a second end of the compensating piston opposite from the first end. 3. The hydraulic valve actuator of claim 2, wherein the compensating piston includes a stop at the first end facing the upper pressure chamber, and the operating piston includes a counter stop corresponding to the stop, enabling cooperative contact between the operating piston and the compensating piston. 4. The hydraulic valve actuator of claim 3, wherein the compensating chamber is blocked across the displacement path of the operating piston and is released for a fluid exchange as the operating piston moves into its upper limit position. 5. The hydraulic valve actuator of claim 4, wherein the operating piston includes an annular groove via which the compensating chamber is connectable to a compensating channel that discharges in the lower discharge opening, an axial width of the annular groove being dimensioned such that the connection between the compensating chamber and the compensating channel is interrupted once the operating piston moves out of the upper limit position. 6. The hydraulic valve actuator of claim 5, wherein an axial clearance between the annular groove and the counter stop on the operating piston is dimensioned such that, when the stop on the compensating piston and the counter stop on the operating piston come into contact, connection between the compensating chamber and the compensating channel is established via the annular groove. 7. The hydraulic valve actuator of claim 3, wherein the compensating chamber is configured to be connected to a fluid reservoir once the compensating piston begins to be carried by the operating piston as the operating piston moves into the upper limit position. 8. The hydraulic valve actuator of claim 7, wherein the compensating chamber is configured to be permanently connected to the fluid reservoir. 9. The hydraulic valve actuator of claim 7, wherein the operating piston includes an annular groove positioned to establish a connection to the fluid reservoir when contact is made between the stop of the compensating piston and the counter stop of the operating piston. 10. The hydraulic valve actuator of claim 9, wherein the housing includes a radial bore connected to the fluid reservoir, and an axial groove width of the annular groove is dimensioned such that the annular groove is connectable to an outlet of the radial bore and the compensating chamber. 11. The hydraulic valve actuator of claim 10, wherein the fluid reservoir includes a control chamber having two chamber openings lying axially opposite one another and a control member axially displaceable in the control chamber, wherein the control member alternately closes one chamber opening and releases the other chamber opening, a first of the two chamber openings being connected to the radial bore in the housing and a second of the two chamber openings being configured to be acted on by a fluid pressure that is slightly greater than a fluid pressure prevailing in the compensating chamber when the operating piston is in the upper limit position. 12. The hydraulic valve actuator of claim 11, wherein the control chamber is connected to the radial bore in the housing via a throttle. 13. The hydraulic valve actuator of claim 11, wherein each of the two chamber openings includes a frustoconical valve seat and the control member is configured as a ball. 14. The hydraulic valve actuator of claims claim 11, wherein a pressure-modulating valve having an output is disposed between the first control valve and the fluid reservoir, and the second of the two chamber openings of the control chamber is connected to the output of the pressure-modulating valve. 15. The hydraulic valve actuator of claim 11, wherein the upper pressure chamber is connected to the intake line configured to be alternatively shut off via a second control valve and connected to a pressure-supply device delivering fluid under high pressure. 16. The hydraulic valve actuator of claim 3, wherein a stop is situated in the upper pressure chamber to delimit displacement of the compensating piston. 17. The hydraulic valve actuator as recited in claim 16, wherein the stop in the upper pressure chamber includes a spacer ring having a radial bore corresponding to the upper discharge opening in the housing. 18. The hydraulic valve actuator of claim 17, wherein one of the upper discharge opening and the radial bore is configured as a throttle bore forming a restrictor, and the lower discharge opening and the upper discharge opening are each connected to one of two line branches of the return line. 19. The hydraulic valve actuator of claim 18, wherein the return line is configured to be alternatively shut off via a first control valve and connected to a fluid reservoir. 20. The hydraulic valve actuator of claim 17, wherein the upper discharge opening simultaneously forms an intake and is connected to the intake line, the lower discharge opening is connected to the return line and the restrictor is disposed in a connecting line coupled to the intake line and to the return line.
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이 특허에 인용된 특허 (5)
Schechter Michael M. (Farmington Hills MI), Fast start hydraulic system for electrohydraulic valvetrain.
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