Patent ID: 7124966

Claim:
A high pressure unit fuel injector comprising: a member with a fuel delivery opening to be intermittently supplied with high pressure fuel and a valve seat encircling the fuel delivery opening; a valve cage including a check-valve chamber adjacent the valve seat; wherein the check-valve chamber includes an annular ledge facing the valve seat and an inwardly facing wall surrounding the ledge; a check-valve disk movable within the check-valve chamber between the valve seat and the annular ledge and having opposite first and second faces alternately seatable against the valve seat and the ledge respectively; wherein the disk has an outer edge in opposed relation to the wall and having limited radial clearance therefrom when centered in the check-valve chamber; wherein the disk has a plurality of openings between the first and second faces for passage of fuel past the disk; wherein the disk has a groove formed in the first face; and wherein the groove is located about the fuel delivery opening to provide a flow path from the fuel delivery opening to the plurality of openings, for even and steady movement of the disk as it breaks away form the valve seat.