| 摘要 |
<p>A fuel injection nozzle unit includes a differential valve member biased by a spring to a closed position and opened to allow fuel flow through an outlet by fuel under pressure from an inlet. The spring is housed within a spring chamber and fuel leaking into this chamber is vented to the inlet when delivery of fuel has ceased. A relief valve is provided which has a valve element having a surface exposed to the pressure in the chamber and an opposing surface exposed to the pressure exterior of the nozzle unit. The valve element is biased to a closed position by a spring and it controls flow along a path from the chamber to the inlet. The flow path also incorporates a non-return valve. The valve element is set to lift from its seating at a pressure which is greater than the residual pressure in the inlet plus the pressure required to open the non-return valve.</p> |
