Fuel injection nozzle

A fuel injection nozzle for the delivery of fuel, premixed with air, to the combustion chamber of a cylinder in an internal combustion engine, comprising:

• (a) a hollow nozzle body having formed therein at least one spray hole adapted to open to the combustion chamber of the engine cylinder;
• (b) a piston slidably mounted in the nozzle body for reciprocating movement between a first and a second position and defining therein a premixing chamber to be placed in and out of communication with the combustion chamber of the engine cylinder via the spray hole, the piston having a bore formed axially therein;
• (c) there being in the nozzle body a fuel inlet port and an air inlet port which are both open to the premixing chamber when the piston is in the first position and which are closed by the piston upon movement thereof from the first toward the second position;
• (d) a valve member slidably fitted in the bore in the piston and having one end projecting outwardly therefrom for opening and closing the spray hole in the nozzle body;
• and
• (e) spring means acting between the piston and the valve member for normally causing the latter to close the spray hole in the nozzle body;
• (f) the valve member being adapted to be acted upon, during the piston stroke from the first to the second position, by the compressed fuel-air mixture in the premixing chamber so as to move against the force of the spring means for opening the spray hole.