| 摘要 |
<p>An intensified hydraulically-actuated, electronically-controlled unit injector (8) for delivering a quantity of a fuel to a combustion chamber of an internal combustion engine is provided with a fuel injection event controller (6) to provide pilot injection or rate shaping of the injection charge. The fuel injection event controller (6) includes a hydraulic lock valve (39) for sealing a chamber (40) to thereby restrict the translational movement of a seal pin (36) associated with the opening of a fuel injection nozzle needle valve (18). Upon the intensified fuel pressure in the nozzle supply passage (34) overcoming the hydraulic actuating pressure present in the passage (52), as intensified by the differential areas (50, 54) of the hydraulic lock valve (39), the hydraulic lock valve shifts to release the pressure in chamber (40) thereby permitting movement of the seal pin (36) and needle valve (18). Methods of effecting rate shaping of the injection charge and of providing a two-stage injection event are included.</p> |
