Patent ID: 6390069
Filing Date: 2002-05-21
Classification: F02M

Abstract:
A fuel injector assembly, comprising:an injector body having a fuel inlet, a spill port and being structured and arranged to contain and disperse fluid fuel; an injector nozzle assembly including a fuel outlet, said nozzle assembly being attached to said injector body and structured and arranged for dispersing fluid fuel from said fuel outlet to a combustion chamber; a plunger disposed within said injector body and structured and arranged for reciprocating movement to pressurize fluid fuel within said injector body and said injector nozzle assembly to disperse fluid fuel from said fuel outlet to a combustion chamber; a control valve and a control seat associated with said control valve, said control valve associated with said injector body and structured and arranged to direct flow of fluid fuel between (a) said fuel outlet and said spill port in an open mode and (b) said fuel inlet and said injector nozzle assembly and fuel outlet to disperse fluid fuel to said combustion chamber in a closed mode; a piezoelectric actuator associated with said injector body and structured and arranged for voltage excitation, an axial dimension of said actuator being changed upon said excitation, said control valve and associated control seat are structured and arranged (a) to provide a reduced flow of fluid fuel through said control valve and to said spill port, and to provide some dispersion of fuel at said fuel outlet into said combustion chamber, in a first stage of excitation of said piezoelectric actuator and (b) to eliminate flow of fluid fuel through said control valve and to said spill port, thereby permitting maximum dispersing of fuel from said fuel outlet to said combustion chamber, in a second stage excitation of said piezoelectric actuator; a hydraulic amplifier structured and arranged to magnify said axial dimension and thereby permit opening and closing of said control valve in said open mode and said closed mode, respectively, said hydraulic amplifier comprising a first piton coupled with said actuator, a second piston coupled with said control valve and a hydraulic fuel chamber therebetween; and a pressure check valve structured and arranged to selectively supply fluid fuel from said fuel inlet to said hydraulic fuel chamber, said fluid fuel in said hydraulic fuel chamber being (a) pressurized between said first piston and said second piston, when said piezoelectric actuator is excited, to close said control valve in said closed mode, and (b) depressurized, when said piezoelectric actuator is not excited, to permit opening of said control valve in said open mode.