Fuel injector nozzle assembly with feedback control

A closed nozzle injector for injecting fuel at high pressure into the combustion chamber of an engine, comprising:

• an injector body containing an injector cavity and an injector orifice communicating with one end of said injector cavity to discharge fuel into the combustion chamber;
• a nozzle valve element positioned in one end of said injector cavity adjacent said injector orifice, said nozzle valve element movable between an open position in which fuel may flow through said injector orifice into the combustion chamber and a closed position in which fuel flow through said injector orifice is blocked;
• a control volume positioned to receive a pressurized supply of fuel;
• a drain circuit for draining fuel from said control volume to a low pressure drain;
• and
• an injection control valve positioned along said drain circuit and including a reciprocally mounted control valve member movable toward an outer end of said nozzle valve element into an open position and away from said nozzle valve element into a closed position, said control valve member being positioned for contact by nozzle valve element when said nozzle valve element is in said open position.

A closed nozzle injector for injecting fuel at high pressure into the combustion chamber of an engine, comprising:

• an injector body containing an injector cavity and an injector orifice communicating with one end of said injector cavity to discharge fuel into the combustion chamber, said injector body including a fuel transfer circuit for transferring supply fuel to said injector orifice;
• a nozzle valve element positioned in one end of said injector cavity adjacent said injector orifice, said nozzle valve element movable between an open position in which fuel may flow from said fuel transfer circuit through said injector orifice into the combustion chamber and a closed position in which fuel flow through said injector orifice is blocked, movement of said nozzle valve element from said closed position to said open position and from said open position to said closed position defining an injection event during which fuel may flow through said injector orifice into the combustion chamber;
• a nozzle valve control means for moving said nozzle valve element between said open and said closed positions, said nozzle valve control means including a control volume positioned adjacent an outer end of said nozzle valve element, a control volume charge circuit for supplying fuel from said fuel transfer circuit to said control volume, a drain circuit for draining fuel from said control volume to a low pressure drain, and an injection control valve positioned along said drain circuit and operable to control the flow of fuel through said drain circuit, wherein said nozzle valve element is positioned to contact said injection control valve to define an outermost open position of said nozzle valve element.

A closed nozzle injector for injecting fuel at high pressure into the combustion chamber of an engine, comprising:

• an injector body containing an injector cavity and an injector orifice communicating with one end of said injector cavity to discharge fuel into the combustion chamber;
• a nozzle valve element positioned in one end of said injector cavity adjacent said injector orifice, said nozzle valve element movable between an open position in which fuel may flow through said injector orifice into the combustion chamber and a closed position in which fuel flow through said injector orifice is blocked;
• a control volume positioned to receive a pressurized supply of fuel;
• a drain circuit for draining fuel from said control volume to a low pressure drain;
• an injection control valve positioned along said drain circuit to control fuel flow from said control volume, said injection control valve including a reciprocally mounted control valve member movable between open and closed positions;
• and
• control valve member movement detecting means for detecting movement of said control valve member into at least one of said open and said closed positions and for providing a control valve member position feedback signal, wherein said injection control valve further includes a piezoelectric actuator including piezoelectric elements adapted to cause movement of said control valve member between open and closed positions, said control valve member movement detecting means including at least a portion of said piezoelectric elements.