Fuel injection nozzle with auxiliary spray orifice

Claim 1

A fuel injection nozzle assembly comprising an elongated holder, a nozzle assembly having an axial bore mounted at one axial end of said holder, a valve mounted in said axial bore, the lower terminal end of said axial bore terminating in a conical valve seat and a sac hole below said seat, said valve having a tip end including a conical portion and a pintle projecting from said conical portion, means defining at least one fuel discharge orifice in the nozzle communicating at its inner end with said sac hole, means defining an auxiliary orifice of smaller cross section than said main discharge orifice, the inner terminal end of said auxiliary orifice terminating at said valve seat, said auxiliary orifice being in the range of 12 percent to 20 percent of the total discharge orifice area and being of a length no greater than four times its diameter, the outer terminal end of said auxiliary orifice being flared outwardly, said valve operable between a closed position wherein the pintle snugly engages in said sac hole and said conical portion overlies the inner terminal end of said auxiliary orifice to seal the same and an open position permitting fuel flow through said orifices, said pintle being of an axial length equal to at least one-half the total valve lift.