Patent ID: 9228550
Filing Date: 2016-01-05
CPC Classification: F02M

Claim Text:
1. A fuel injector having a needle that closes off an injection orifice when subjected to high fuel supply pressure at upper and lower elevations of the needle and opens when the needle is subjected to a reduced pressure at the upper elevation, said upper elevation situated in a needle control chamber at a pressure subject to a control valve in a control valve chamber in hydraulic communication with said needle control chamber whereby in an opening phase the control valve is lifted from a control valve seat to expose the control valve chamber and needle control chamber to a low pressure drain and in a closing phase is urged in a closing direction against said control valve seat to isolate the control valve chamber and needle control chamber from the drain, the improvement comprising means for resisting fuel flow from the needle control chamber in the closing direction through the control valve seat toward said drain as the control valve closes, wherein a flow passage extends from the control valve seat to said low pressure drain and includes a cylindrical bore wall immediately downstream of the control valve seat, followed downstream by a conically enlarging bore wall; the means for resisting flow of fuel through the control valve seat is a pressure regulating valve situated in the flow passage; a pressure regulated volume extends between the control valve seat and the means for resisting fuel flow; said control valve includes a pintle having a collar defining an annular throttle flow area between the collar and the cylindrical bore wall and a nose that extends into said conically enlarged bore wall; said cylindrical bore wall defines at least a portion of the pressure regulated volume; and said pressure regulating valve is situated downstream of the conical bore wall.