| 摘要 |
<p>A hydraulically-actuated fuel injector (10) includes an injector body (11) that defines an actuation fluid inlet (13), a first actuation fluid cavity (34), a second actuation fluid cavity (38) and a nozzle outlet (16). A piston (35) is positioned in the injector body (11) and is moveable between a retracted position and an advanced position. The piston (35) has a primary hydraulic surface (37) exposed to fluid in the first actuation fluid cavity (34), and an opposing hydraulic surface (39) exposed to fluid in the second actuation fluid cavtiy (38). A control valve (12) includes a spool valve member (60) that is moveable a distance between a first position and a second position. The first actuation fluid cavity (34) is closed to the actuation fluid inlet (13) when the spool valve member (60) is in its first position. The first actuation fluid cavity (34) is open, but the second actuation fluid cavity (38) is closed, to the actuation fluid inlet (13) when the spool valve member (60) is moving through a first portion of the distance. The first actuation fluid cavity (34) and the second actuation fluid cavity (38) are open to the actuation fluid inlet (13) when the spool valve member (60) is moving through a second portion of the distance. The first actuation fluid cavity (34) is open to the actuation fluid inlet (13) when the spool valve member (60) is in its second position.</p> |
