Diesel fuel injection nozzle

A nozzle assembly for the injection of premixed fuel and air into a diesel engine cylinder, comprising:

• (a) a nozzle body having a bore formed therein;
• (b) a bored piston reciprocably mounted in the bore in the nozzle body and defining a premixing chamber therein, the premixing chamber having a fuel inlet port and an air inlet port, for the admission of fuel and air, which are both covered and uncovered by the piston;
• (c) a plunger having one end slidably engaged in the bore in the piston to define a pressure chamber therein and having the other end arranged for movement out of and back into the nozzle body, the pressure chamber being adapted to exert, during the stroke of the piston in a direction to compress the fuel and air admitted into the premixing chamber, a variable fluid pressure on the plunger for urging same in such a direction as to cause the movement of said other end thereof out of the nozzle body;
• (d) there being spray hole in said other end of the plunger for spraying the compressed fuel-air mixture into the diesel engine cylinder from the premixing chamber upon movement of said other end of the plunger out of the nozzle body;
• and
• (e) a step formed on the plunger and situated in the premixing chamber so that the fuel-air mixture being compressed therein by the piston acts on the step of the plunger for holding said other end thereof retracted against the fluid pressure in the pressure chamber, until the piston moves into positive engagement with the plunger for moving said other end thereof out of the nozzle body.