Fuel injection nozzle for combustion engines

Claim 1

A fuel injection nozzle having an inlet end from which direction fuel flows and an injection end from which fuel is injected for combustion engines comprising a nozzle housing having a flat injection end surface, a bore in said nozzle housing, said bore including a small diameter section and an enlarged cylindrical end portion of uniform diameter which directly adjoins said small diameter section to form a valve seat through which a fuel jet is discharged, said enlarged cylindrical end portion extending from said valve seat to said flat injection end surface of said housing, a valve needle in said bore, said valve needle including a valve needle head portion, said valve needle head portion including a conical section with a cross sectional portion of greater diameter than said valve seat which conical section is arranged to close against said valve seat to close said bore and arranged to open in the direction of fuel flow, said valve needle head portion including a cylindrical portion of uniform diameter which adjoins said conical portion and extends downstream of said conical portion, said cylindrical head portion extends into said enlarged cylindrical end portion of said bore with a slight radial play when said valve needle is seated in a closed position against said valve seat, said valve needle head portion further includes a cone portion extending axially from said cylindrical portion with the vertex end of the cone in the direction of fuel injection to thereby shape the fuel jet emitted by said nozzle.