Patent ID: 8267333

Claim:
A fuel injector, comprising: a housing; a valve disposed in the housing and including a first port and a second port, the valve moveable between a first position, in which the first port is fluidly coupled to the second port, and a second position, in which the first port is fluidly blocked from the second port; a needle housing disposed within the housing, the needle housing defining a needle chamber and a plurality of openings; a fuel inlet port formed in the housing, the fuel inlet port in continuous fluid communication with the needle chamber; a needle guide located in the housing and disposed to provide a guide opening; a needle disposed in the needle chamber, the needle defining a guide portion and a seat portion, the guide portion disposed in the guide opening, the seat portion contacting the needle housing when the needle is in a closed position such that the plurality of openings are fluidly isolated from the needle chamber; a second plate disposed proximate to the needle guide and disposed to form a bore opening aligning with and extending the guide opening; a first plate stacked on the second plate and forming a first orifice, the first orifice being in fluid communication with the first port of the valve; the needle having a closing hydraulic surface defined thereon, the closing hydraulic surface disposed in a control chamber; the control chamber defined between the closing hydraulic surface, the bore opening in the second plate, and a surface of the first plate surrounding an end of the first orifice, such that the control chamber is directly fluidly connected to the first orifice; a second orifice formed in the second plate, the second orifice fluidly coupling the needle chamber to the control chamber; a clearance flow area defined between the guide portion of the needle, the guide opening, and the bore opening, the clearance flow area fluidly connecting the needle chamber with the control chamber; wherein a flow area of the first orifice is greater than the clearance flow area.