摘要 |
A fluid driven piston assembly, preferably for use in a hydraulically-actuated fuel injector, includes a body that defines an actuation fluid cavity and a piston bore. A piston is positioned in the piston bore and moveable between a retracted position and an advanced position. The piston has a pressure surface exposed to fluid pressure in the actuation fluid cavity when it is away from its retracted position. A sealing member is positioned in sealing contact between the piston and the body when the piston is in its retracted position. The sealing member isolates a portion of the piston's pressure surface from the fluid pressure in the actuation fluid cavity when the piston is in its retracted position.
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