| 摘要 |
To provide for gradual admission of servo fluid to then operate a fuel injection pump to pus injected fuel out through the nozzle, a control valve element is used which has a displacement or deflection-vs.-servo fluid admission characteristic which provides for hydraulic choking of pressurized servo fluid being admitted to a servo cylinder chamber upon initiation of a fuel injection event, and thereby provide for gradual build-up of injection pressure of the fuel. By suitable shaping of the choke ducts, the admission of fuel can be first of a small quantity, then interrupted, and then of a selected, for example full servo fluid quantity; this can be accomplished by forming an intermediate land on a control slider or rotary valve element with a connecting passage forming a choke; or gradually decreasing choking effect of fluid admission, for example by forming relatively movable control surfaces at an inclination so that, upon initial opening of a fluid path, the inclined surface will provide for a constricted passage-way which then gradually opens to full admission of pressurized servo fluid.
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