Abstract: A fuel injector and a method of assembly includes a determination of various flow areas through clearances or openings formed in various components of the injector. With the various flow areas determined, the various components can be classified according to their flow areas such that sets of components can be selected having desirable flow area characteristics for assembly of the fuel injector.

Abstract: A fuel injector for a common rail fuel system includes a common rail inlet port fluidly connected to a high pressure common rail, and a cooling inlet fluidly connected to an output from a lower pressure fuel transfer pump. The cooling fluid circulates internally through the fuel injector to cool a single pole solenoid via both internal and peripheral cooling passages. In order to accommodate a small spatial envelope while providing superior performance, a thin insulating layer may separate the solenoid coil winding from an inner pole piece, and small flux gap clearances may permit a flux carrying portion of the injector body to be a portion of the single pole solenoid assembly.

Abstract: A fuel injector for a common rail fuel system includes a common rail inlet port fluidly connected to a high pressure common rail, and a cooling inlet fluidly connected to an output from a lower pressure fuel transfer pump. The cooling fluid circulates internally through the fuel injector to cool a single pole solenoid via both internal and peripheral cooling passages. In order to accommodate a small spatial envelope while providing superior performance, a thin insulating layer may separate the solenoid coil winding from an inner pole piece, and small flux gap clearances may permit a flux carrying portion of the injector body to be a portion of the single pole solenoid assembly.

Abstract: An internal combustion engine, such as a direct injection compression ignition diesel engine, includes an engine housing having a plurality of cylinders and a plurality of fuel injectors associated one with each of the cylinders. The fuel injectors each include a first fuel inlet and a second fuel inlet, and an actuator subassembly which is configured to actuate a control valve assembly positioned within the fuel injector. The engine further includes a fuel system having a fuel supply circuit, and a cooling system for the actuator subassembly having a cooling circuit with a segment in common with a segment of the fuel system. The cooling system is configured to pass cooling fuel across a heat exchange interface of the actuator subassembly to exchange heat therewith. The actuator subassembly may include a piezoelectric actuator and a preloading spring, which are each fluidly sealed within a casing of the actuator subassembly.

Abstract: A fuel injector and a method of assembly includes a determination of various flow areas through clearances or openings formed in various components of the injector. With the various flow areas determined, the various components can be classified according to their flow areas such that sets of components can be selected having desirable flow area characteristics for assembly of the fuel injector.

Abstract: A fuel injector and a method of assembly includes a determination of various flow areas through clearances or openings formed in various components of the injector. With the various flow areas determined, the various components can be classified according to their flow areas such that sets of components can be selected having desirable flow area characteristics for assembly of the fuel injector.

Abstract: A self-guided armature assembly for a single pole solenoid assembly includes an armature stem and an armature. The solenoid assembly includes a flux ring component and an actuator body. The armature is movable inside the flux ring. An axial air gap is defined between the top armature surface of the armature and a bottom stator surface of a stator assembly. A sliding air gap is defined between an inner diameter surface of the flux ring and an outer diameter surface of the armature. The self-guided armature is guided along the flux ring via a guiding interaction between the armature and the flux ring. The sliding air gap is smaller than the axial air gap. A stem clearance gap is defined between the armature stem and the actuator body. The sliding air gap is also smaller than the stem clearance gap.

Abstract: A self-guided armature assembly for a single pole solenoid assembly includes an armature stem and an armature. The solenoid assembly includes a flux ring component and an actuator body. The armature is movable inside the flux ring. An axial air gap is defined between the top armature surface of the armature and a bottom stator surface of a stator assembly. A sliding air gap is defined between an inner diameter surface of the flux ring and an outer diameter surface of the armature. The self-guided armature is guided along the flux ring via a guiding interaction between the armature and the flux ring. The sliding air gap is smaller than the axial air gap. A stem clearance gap is defined between the armature stem and the actuator body. The sliding air gap is also smaller than the stem clearance gap.

Abstract: A fuel injector for a common rail fuel system includes a common rail inlet port fluidly connected to a high pressure common rail, and a cooling inlet fluidly connected to an output from a lower pressure fuel transfer pump. The cooling fluid circulates internally through the fuel injector to cool a single pole solenoid via both internal and peripheral cooling passages. In order to accommodate a small spatial envelope while providing superior performance, a thin insulating layer may separate the solenoid coil winding from an inner pole piece, and small flux gap clearances may permit a flux carrying portion of the injector body to be a portion of the single pole solenoid assembly.

Abstract: A fuel injector includes a piezoelectric actuator subassembly having a casing and a piezoelectric element disposed within the casing. The piezoelectric element has an operating temperature range and includes a thermally contractive material having a negative thermal expansion coefficient over a second temperature range overlapping with the operating temperature range. A preload control element is coupled with the piezoelectric element and includes a thermally expansive material having a positive thermal expansion coefficient over the second temperature range. The preload control element maintains a constant preload on the piezoelectric element over a wide temperature range to inhibit temperature induced variability in operation, and can axially lengthen in opposition to axial shortening of the piezoelectric element, responsive to a temperature increase.

Abstract: An internal combustion engine, such as a direct injection compression ignition diesel engine, includes an engine housing having a plurality of cylinders and a plurality of fuel injectors associated one with each of the cylinders. The fuel injectors each include a first fuel inlet and a second fuel inlet, and an actuator subassembly which is configured to actuate a control valve assembly positioned within the fuel injector. The engine further includes a fuel system having a fuel supply circuit, and a cooling system for the actuator subassembly having a cooling circuit with a segment in common with a segment of the fuel system. The cooling system is configured to pass cooling fuel across a heat exchange interface of the actuator subassembly to exchange heat therewith. The actuator subassembly may include a piezoelectric actuator and a preloading spring, which are each fluidly sealed within a casing of the actuator subassembly.

Abstract: A fuel injector includes a piezoelectric actuator subassembly having a casing and a piezoelectric element disposed within the casing. The piezoelectric element has an operating temperature range and includes a thermally contractive material having a negative thermal expansion coefficient over a second temperature range overlapping with the operating temperature range. A preload control element is coupled with the piezoelectric element and includes a thermally expansive material having a positive thermal expansion coefficient over the second temperature range. The preload control element maintains a constant preload on the piezoelectric element over a wide temperature range to inhibit temperature induced variability in operation, and can axially lengthen in opposition to axial shortening of the piezoelectric element, responsive to a temperature increase.

Abstract: A fuel injector and a method of assembly includes a determination of various flow areas through clearances or openings formed in various components of the injector. With the various flow areas determined, the various components can be classified according to their flow areas such that sets of components can be selected having desirable flow area characteristics for assembly of the fuel injector.