Abstract: A dual-mode fuel injector has an internal part containing a variable volume chamber space which fills with fuel at common rail pressure and a plunger which is operable to force fuel out of the variable volume chamber space and to be injected out of the nozzle through the injection orifices at amplified pressure greater than common rail pressure. The plunger and the internal part have respective surfaces which come into mutual abutment during filling of the variable volume chamber space with fuel at common rail pressure and which, when in mutual abutment, create a seal which seals fuel in the variable volume chamber space against escape from the variable volume chamber space past the seal.

Abstract: A needle body for a fuel injector that controls or prevents high pressure fuel leaks by dynamically controlling the size of the clearance between a longitudinal bore in a nozzle body and the needle that travels along the bore. The longitudinal bore passes through a body portion and a clearance control protrusion of the needle body. The clearance control protrusion extends from the body portion into a nozzle chamber of a nozzle section of the fuel injector. The clearance control protrusion is configured to prevent expansion of the clearance that is typically associated with hydraulic forces caused by pressurized fuel in the clearance. The clearance control protrusion is configured so that as fuel pressure in the nozzle chamber increases, hydraulic forces act against an outer surface of the clearance control protrusion to prevent expansion of the portion of the clearance positioned within the clearance control protrusion.

Abstract: A control valve of a fuel injector includes a generally cylindrical control valve housing having an axis, and a control valve body disposed within the control valve housing. An inlet throttle passage is in fluid communication with the control valve housing and is oriented to be generally tangential to the control valve housing.

Abstract: A fuel injector for an internal combustion engine comprises a fuel intensification section and a needle control section. The fuel intensification section has an inlet and an outlet. The fuel intensification section receives fuel at a first pressure at the inlet and provides fuel at one of the first and second pressures at the outlet. The second pressure is greater than the first pressure. The needle control section has an injector needle and an injector needle control valve. The injector needle has a first position and a second position. The injector needle is disposed in the second position to allow fuel to flow from the fuel injector to the internal combustion engine. The injector needle control valve controls movement of the injector needle. All of the fuel that flows from the fuel injector to the internal combustion engine passes through the fuel outlet of the fuel intensification section.

Abstract: An apparatus and method for measuring the pressure of a fluid near discharge ports 409 in a nozzle 213 of a fuel injector 201 are described. A fuel injector 201 is charged with fluid from a fluid tank 203 by a fuel pump 205. Upon activation of the fuel injector 201, the fluid is discharged from the nozzle 213. Fluid pressure in the nozzle 213 is communicated to a pressure sensor 215 through an orifice 411 in the nozzle 213. The pressure sensor 215 measures fluid pressure near the discharge ports 409 during fuel injector 201 operation.

Abstract: An apparatus and method for measuring the pressure of a fluid near discharge ports 409 in a nozzle 213 of a fuel injector 201 are described. A fuel injector 201 is charged with fluid from a fluid tank 203 by a fuel pump 205. Upon activation of the fuel injector 201, the fluid is discharged from the nozzle 213. Fluid pressure in the nozzle 213 is communicated to a pressure sensor 215 through an orifice 411 in the nozzle 213. The pressure sensor 215 measures fluid pressure near the discharge ports 409 during fuel injector 201 operation.