| 摘要 |
Actuators, and corresponding methods and systems for controlling such actuators, provide independent valve control with a large initial or opening force. In an exemplary embodiment, an actuator includes a driver further including a housing defining a longitudinal axis and first and second directions, an actuation mechanism capable of generating actuation force at least in the first direction, and a rod with one end operably connected with at least one part of the actuation mechanism and with the other end available for an operable connection with a load such as an engine valve; at least one return spring operably connected with the rod through a spring retainer assembly and biasing the rod in the second direction; and a pneumatic booster further including a pneumatic cylinder, a pneumatic piston operably connected with the rod through the spring retainer assembly and biasing the rod in the first direction, a charge mechanism providing a controlled fluid communication between the pneumatic cylinder and a high-pressure gas source, and a bleed mechanism providing a controlled fluid communication between the pneumatic cylinder to a low-pressure gas sink.
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