| 摘要 |
<p>A nozzle assembly for a fuel injector having a needle valve (108) for controlling an injector valve orifice, the needle valve (108) being subjected to a spring force and a fluid pressure force. The needle valve (108) registers with a fuel delivery orifice (112) and is movable into and out of engagement with a valve seat surrounding the orifice. The needle valve is normally biased to a valve closing position by a spring (46) located in a spring cage (48). The spring cage becomes pressurized upon movement of the needle valve toward the needle valve open position, whereby a positive pressure is maintained in the spring chamber throughout the fuel injection event. A calibrated bleed orifice allows the spring chamber pressure to decay to a low value between injection events.</p> |
