FUEL PUMPING DEVICE WITH INCREASED NEEDLE VALVE CLOSURE PRESSURE

摘要

A fuel pumping device (10) includes a pressure-actuated needle valve (30) extending from a spring cage chamber (62) including a spring (60) which biases the needle valve (30) in the closing direction. The fuel pumping device (30) is configured such that the needle valve (30) closes at a high fuel pressure for improved fuel injection. The device (10) includes a body (12) forming a fuel pressurization chamber (14) therein for building fuel pressure to open the needle valve (30) against the spring bias for fuel injection. At least one component comprising a director cage (17) forms a fuel flow passage comprising a small aperture (66) formed in the director cage (17) between the fuel pressurization chamber (14) and the spring cage chamber (62) to assist the spring (60) in closing the needle valve (30) in order to increase the fuel pressure at which the needle valve (30) closes.