Patent ID: 6647966
Filing Date: 2003-11-18
Classification: F02D,F02M

Abstract:
A fuel injector comprising:an injector body defining a nozzle chamber, a needle control chamber, a needle control vent, a fuel inlet and a nozzle outlet; a needle control valve positioned in said injector body and including a poppet control valve member having a first position in which said needle control chamber is fluidly connected to said fuel inlet but closed to said needle control vent, and a second position in which said needle control chamber is closed to said fuel inlet but open to said needle control vent; a needle valve member positioned in said injector body and including a closing hydraulic surface exposed to fluid pressure in said needle control chamber and an opening hydraulic surface exposed to fluid pressure in said nozzle chamber; said needle control valve defines a first flow area; a pressure communication passage extending between said needle control valve and said needle control chamber defines a second flow area that is smaller than said first flow area; and said first flow area has a size that is a function of a combined volume of said needle control chamber and said pressure communication passage.