Idle stabilizing variable area inlet for a hydraulically-actuated fuel injection system

A hydraulically actuated fuel injection system comprising:

• a manifold holding an amount of pressurized actuation fluid therein;
• a plurality of hydraulically actuated fuel injectors, each with an injector body defining an actuation fluid cavity adjacent a piston;
• a plurality of branch passages, each with a first end connected to said manifold and a second end connected to said actuation fluid cavity of a different one of said plurality of hydraulically actuated fuel injectors;
• a flow orifice valve member positioned in each of said branch passages and having a pressure surface exposed to fluid pressure in said manifold, and being movable between a first position that presents a relatively small flow area through said branch passage, and a second position that presents a relatively large flow area through said branch passage;
• and
• a compression spring operably positioned to bias said flow orifice valve member toward said first position.

A hydraulically actuated fuel injection system comprising:

• a manifold holding an amount of pressurized actuation fluid therein;
• a plurality of hydraulically actuated fuel injectors, each with an injector body defining an actuation fluid cavity adjacent a piston;
• a plurality of branch passages, each with a first end connected to said manifold and a second end connected to said actuation fluid cavity of a different one of said plurality of hydraulically actuated fuel injectors;
• a control valve member positioned in each of said branch passages, and being movable between an open position in which said actuation fluid cavity is open to said branch passage, and a closed position in which said actuation fluid cavity is closed to said branch passage;
• said control valve member being movable to a partially open position, which is between said open position and said closed position, when said hydraulically actuated fuel injector is operating in an idle condition;
• and
• a flow orifice valve member positioned in each of said branch passages, and being movable between a first position that presents a relatively small flow area through said branch passage, and a second position that presents a relatively large flow area through said branch passage.