Damped opening poppet covered orifice fuel injection nozzle

Claim 1

A poppet covered orifice fuel injector nozzle for use in a direct injection type diesel engine, said fuel injector nozzle including an injector body means having an inlet for pressurized fuel at one end thereof and having a spray tip at the opposite end thereof; said spray tip having a discharge free end and having an axial stepped through bore of predetermined internal diameter therein at its discharge free end with an annular frusto-conical valve seat encircling said bore at said discharge free end of said spray tip, said bore intermediate its ends defining an enlarged diameter fuel chamber in said injector body means an outward opening poppet valve operatively positioned in said injector body means, said poppet valve including an annular head with a frusto-conical valve seat surface positioned for movement between a closed position and an outward open position relative to said valve seat and a valve stem portion extending from said head that is slidably received in said bore and has its free end loosely received in said fuel chamber, said poppet valve having an internal passage means in fluid communication at one end with said inlet and terminating at its other end in circumferentially spaced apart radial orifices that are inclined and located so as to discharge fuel parallel to and substantially directly across said valve seat surface of said head and a radial passage interconnecting said passage means to said fuel chamber, a retainer means sealingly fixed to said valve stem at said free end thereof opposite said head, a valve lift stop means operatively located in said fuel chamber, a tubular damping piston loosely encircling said valve stem next adjacent to said retainer means within said fuel chamber and spring means operatively positioned in said fuel chamber and operatively associated with said poppet valve to normally bias said head of said poppet valve to said closed position; said frusto-conical valve seat and said valve seat surface together with said discharge free end of said spray tip being configured so that said valve seat surface will effect sealing engagement with said valve seat at substantially the outer peripheral edge thereof with substantially no overhang of these elements with respect to each other whereby to prevent fuel wetting during injection when said head is moved to said open position as controlled by said damping piston and to prevent fuel flow from said orifices when said head is in said closed position.