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A hydraulically-actuated fuel injector includes an injector body that defines an actuation fluid cavity, a piston bore, a plunger bore, a nozzle chamber and a nozzle outlet that opens to the nozzle chamber. A piston is slidably received in the piston bore and moveable between an upper position and a

A hydraulically-actuated fuel injector includes an injector body that defines an actuation fluid cavity, a piston bore, a plunger bore, a nozzle chamber and a nozzle outlet that opens to the nozzle chamber. A piston is slidably received in the piston bore and moveable between an upper position and a lower position. A plunger is slidably positioned in the plunger bore and moveable between a retracted position and an advanced position. A portion of the plunger and the plunger bore define a fuel pressurization chamber that opens to the nozzle chamber. The injector body further defines a nozzle supply passage extending between the fuel pressurization chamber and the nozzle chamber, a spill passage extending between the nozzle supply passage and the nozzle chamber, and a fuel return passage opening into the nozzle chamber. A needle valve member is positioned in the nozzle chamber and moveable a distance between an open position in which the nozzle outlet is open and a closed position in which the nozzle outlet is blocked. The needle valve member blocks the spill passage and the fuel return passage when the needle valve member is in its open position and when it is in its closed position. However, an annulus in the needle valve member opens the spill passage to the fuel return passage over a portion of the travel distance of the needle valve member between its open position and its closed position.

대표청구항 ▼

[ I claim:] [1.] A hydraulically actuated fuel injector comprising:an injector body that defines an actuation fluid cavity, a piston bore, a plunger bore, a nozzle chamber and a nozzle outlet that opens to said nozzle chamber;a piston slidably received in said piston bore and moveable between an upp

[ I claim:] [1.] A hydraulically actuated fuel injector comprising:an injector body that defines an actuation fluid cavity, a piston bore, a plunger bore, a nozzle chamber and a nozzle outlet that opens to said nozzle chamber;a piston slidably received in said piston bore and moveable between an upper position and a lower position;a plunger slidably positioned in said plunger bore and moveable between a retracted position and an advanced position;a portion of said plunger and said plunger bore defining a fuel pressurization chamber that opens to said nozzle chamber;said injector body further defining a nozzle supply passage extending between said fuel pressurization chamber and said nozzle chamber, a spill passage extending between said nozzle supply passage and said nozzle chamber, and a fuel return passage opening into said nozzle chamber;a needle valve member positioned in said nozzle chamber and moveable a distance between an open position in which said nozzle outlet is open and a closed position in which said nozzle outlet is blocked; andsaid needle valve member blocking said spill passage and said fuel return passage when said needle valve member is in said open position and said closed position, but said spill passage being open to said fuel return passage over a portion of said distance between said open position and said closed position.