Hydraulic actuator for actuating a gas exchange valve of an internal combustion engine
AssigneeMahle Ventiltrieb GmbH
InventorDiogenes Perez Cuadro
Life of this patent
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Abstract
The invention relates to a hydraulic actuator for actuating a gas exchange valve (1) of an internal combustion engine, which valve is especially closed by the effect of a spring. The actuator is configured by a feed pump (6) with intermittent and thus variable delivery. The feed pump (6) has a high frequency and can be equipped for this purpose with piezoelectric, magnetorestrictive and/or electrochemical actuators as the feed elements. Optionally, the feed pump (6) can be operated with a stop valve (7) that is disposed downstream of the gas exchange valve (1) and that is controlled or regulated depending on the feed pump.
Claims13
An actuator for actuating the gas exchange valves of an internal combustion engine, whereby the gas exchange valves are actuated by hydraulic fluid conveyed by a feed pump in an open circuit equipped with a storage tank, whereby
- the opening or closing of the gas exchange valves is produced by actuating forces emanating from the hydraulic fluid flowing through the circuit and acting at different levels on the respective gas exchange valve to be actuated,
- downstream from the respective gas exchange valve, the flow cross section of the circuit is constricted or even closed with respect to all areas upstream from this gas exchange valve, at least during the duration of a hydraulically actuated opening or closing of the gas exchange valve,
- the hydraulic actuating force on the gas exchange valve is counteracted by a force, in particular a spring force,
- characterized in that
- the feed pump (6) is designed for a delivery operation which operates intermittently and works at a clock frequency above that of the opening and closing frequency of the gas exchange valves.
A method of operating an actuator for actuating gas exchange valves of an internal combustion engine comprising the steps of:
- (a) providing an actuator wherein the gas exchange valves are actuated by hydraulic fluid conveyed by a feed pump in an open circuit equipped with a storage tank, wherein:
- the opening or closing of the gas exchange valves is produced by actuating forces emanating from the hydraulic fluid flowing through the circuit and acting at different levels on the respective gas exchange valve to be actuated;
- downstream from the respective gas exchange valve, the flow cross section of the circuit is constricted or closed with respect to all areas upstream from this gas exchange valve, at least during the duration of a hydraulically actuated opening or closing of the gas exchange valve;
- and
- the hydraulic actuating force on the gas exchange valve is counteracted by a spring force;
- and
- (b) operating the feed pump for an intermittent delivery operation at a clock frequency above that of the opening and closing frequency of the gas exchange valves;
- wherein the feed pump produces a braking force which acts on the respective gas exchange valve during the period of time in which a respective gas exchange valve is closed through targeted delivery operation within the hydraulic fluid circulation.
Dependencies are inferred from the claim text.