Abstract: A piezoelectric actuator of multiple piezoelectric layers in an integrally bonded laminate structure. Alternating layers of electrically active ceramic material and conductive or non-conductive substrate material are stacked with layers of conductive or non-conductive thermally activated adhesive therebetween. The stacked layers are heated to flow the adhesive and subsequently cooled to effect an integral bonding of the layers and a doming of the stacked device. Conductive substrate materials and adhesive materials may be used, with every other substrate layer being reverse poled to create alternating positive and negative electrode substrate layers capable of applying an electric field to active ceramic layers therebetween. Alternatively, electrically active layers are provide with thin metal electrode layers on opposing surfaces which are capable of applying an electric field to active ceramic layers therebetween.

Abstract: A method for producing a piezoelectric actuator of multiple piezoelectric layers in an integrally bonded laminate structure. Alternating layers of electrically active ceramic material and conductive or non-conductive substrate material are stacked with layers of conductive or non-conductive thermally activated adhesive therebetween. The stacked layers are heated to flow the adhesive and subsequently cooled to effect an integral bonding of the layers and a doming of the stacked device. Conductive substrate materials and adhesive materials may be used, with every other substrate layer being reverse poled to create alternating positive and negative electrode substrate layers capable of applying an electric field to active ceramic layers therebetween. Alternatively, electrically active layers are provide with thin metal electrode layers on opposing surfaces which are capable of applying an electric field to active ceramic layers therebetween.

Abstract: A clamping device for providing temperature compensation of a piezoelectric device, such as a thermally pre-stressed bending actuator. The clamping device is configured to apply a variable clamping force to the piezoelectric device that varies in response to temperature changes proximate the piezoelectric device. The variable clamping force applied to the piezoelectric device alters its operating characteristics to provide temperature compensation of the device.

Abstract: A single pole solenoid assembly includes a coil attached to a stator that is in a fixed position relative to a body component. An armature with a centerline is positioned adjacent to the stator. A magnetic flux ring has a central axis and an interior surface that at least partially surrounds the armature. The stator, armature and magnetic flux ring are positioned and arranged such that magnetic flux line generated by the coil pass through the stator and the magnetic flux ring through the armature. The central axis and the centerline are concentrically coupled via an interaction between the magnetic flux ring and the armature via the body component. The single pole solenoid is preferably attached to valving components and incorporated as part of an electronically controlled fuel injector.

Abstract: A fuel injector includes first and second valves and a solenoid including a solenoid coil and an armature assembly wherein the first and second valves are coupled to the armature assembly. A solenoid drive circuit is coupled to the solenoid coil and delivers a first current waveform portion to the solenoid coil at a first time to cause the armature assembly to operate the first valve without operating the second valve. A second current waveform portion different than the first current waveform portion is applied to the solenoid coil at a second time later than the first time to operate the second valve.

Abstract: A method of operating a fuel injector comprises the steps of applying a test waveform to a solenoid coil of the injector to cause a response by an armature assembly and measuring the response of the armature assembly while the test waveform is applied to the solenoid coil. A control waveform for the injector is developed as a function of the variation of the measured response of the armature from a selected operational characteristic. The developed control waveform is thereafter applied to the solenoid coil to cause the armature assembly to approach a nominal position.

Abstract: A fuel injector includes a solenoid having two armatures which are complementarily shaped to define a stepped armature gap.

Abstract: A fuel injector solenoid includes a solenoid coil disposed in a stator, a flux conduction element carried by the stator and a flux blocking element disposed within a central recess of the stator and surrounded by the flux conduction element. First and second armatures are disposed in the central recess on opposite sides of the flux blocking element.

Abstract: An actuation valve for a hydraulically-operated fuel injector includes an actuator having a plunger and a spool valve coupled to the plunger. The spool valve includes a high pressure port and is operable by the actuator to selectively place the high pressure port or the low pressure port in fluid communication with an injection mechanism of the injector.