Fuel injection nozzle assembly

Claim 1

A fuel injection nozzle assembly for the injection of fuel under pressure from a fuel injection pump into a combustion chamber of an internal combustion engine, comprising: a nozzle body having formed therein a storage chamber for receiving incoming pressurized fuel and a spray orifice for discharging in the form of droplets said pressurized fuel from said storage chamber; a needle valve within said storage chamber for closing and opening said spray orifice, said needle valve having a small diameter portion positioned at said spray orifice and adapted to close and open said spray orifice, a central large diameter portion and a spring retainer portion, and having a blind hole formed in said spring retainer portion and said large diameter portion and opening to said storage chamber; a check valve including a large diameter cylindrical section formed with a recess at one end to define a fuel inlet chamber, a stem portion extending from the other end of said cylindrical section, and an axial passage extending through said cylindrical section and said stem portion, said check valve being positioned in said storage chamber with said stem portion slidably mounted in said blind hole of said needle valve, whereby said axial passage connects said fuel inlet chamber with the interior of said blind hole; a spring positioned in said storage chamber between said spring retainer portion of said needle valve and said cylindrical section of said check valve and adapted to bias said needle valve to close said spray orifice and to bias said check valve recessed cylindrical portion against a wall of said body to form said fuel inlet chamber; and a fuel inlet port in said wall of said body in communication with said fuel inlet chamber and adapted to be connected to said fuel injection pump to allow introduction of pressurized fuel into said storage chamber via said inlet chamber and said check valve against the bias of said spring.