| 摘要 |
A unit fuel injector assembly (2, 88) is disclosed for periodically injecting fuel of a variable quantity on a cycle to cycle basis as a function of the pressure of fuel supplied to the injector from a source of fuel (48) and at a variable time during each cycle as a function of the pressure of a timing fluid supplied to the injector from a source of timing fluid (54). A reciprocating plunger assembly (24,146) is received within the injector body (10, 106) and includes an upper plunger section (26, 148), a lower plunger section (28,150) and an intermediate plunger section (30,152) in order to define a variable volume timing chamber (32,138), a variable volume injection chamber (34,162) and a variable volume compensation chamber (36,176). Biasing means (38) including upper compression spring (40,180) and lower compression spring (42, 182) are arranged in the compensation chamber (36,176) to independently bias the lower plunger section (28,150) and the intermediate plunger section (30,152) in opposite directions to tend to collapse the timing chamber (32,138) and injection chamber (34,162). A plurality of passages (58,158,188,194) are provided to cause both the timing chambers (32,138) and the injection chamber (162) to be spilled near the end of each injection event to produce a sharper end of injection and compensation for wear in the cam-operated, actuating mechanism (4).
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