Abstract: A control system comprises a TRAS actuator 14, a VAFN actuator 40, and a control arrangement 52 operable to control the operation of the TRAS actuator 14 and the VAFN actuator 40, wherein at least one control circuit 54 of the control arrangement 52 is a common control circuit, common to the operation of both the TRAS actuator 14 and the VAFN actuator 40.

Abstract: A piezoelectric actuator comprises a stack of piezoelectric elements formed from piezoelectric material, a plurality of positive internal electrodes interdigitated with a plurality of negative internal electrodes to define active regions of the piezoelectric material which are responsive to a voltage being applied across the internal electrodes, in use. The active regions are responsive to voltage applied across the internal electrodes, in use. The piezoelectric actuator also comprises an external positive electrode for connection to the positive internal electrodes and an external negative electrode for connection to the negative internal electrodes.

Abstract: A piezoelectric actuator for use in a fuel injection system of an internal combustion engine, the actuator comprising a stack of ferroelectric layers; an encapsulation for protecting the stack from the ingress of liquid; and oxygenation means for providing oxygen to the ferroelectric layers, the means positioned between the encapsulation and stack. The oxygenation means is preferably impregnated in a fabric which forms a layer between the encapsulation and the stack.

Abstract: A piezoelectric actuator for use in a fuel injection system of an internal combustion engine, the actuator comprising a stack of ferroelectric layers; an encapsulation for protecting the stack from the ingress of liquid; and oxygenation means for providing oxygen to the ferroelectric layers, the means positioned between the encapsulation and stack. The oxygenation means is preferably impregnated in a fabric which forms a layer between the encapsulation and the stack.

Abstract: A method of assembling a piezoelectric actuator arrangement comprises providing a piezoelectric element having first and second ends and arranging the piezoelectric element within a sleeve member such that the inner surface of the sleeve member defines, together with the outer surface of the piezoelectric element, a chamber for receiving a first filler material. The first filler material is injected into the chamber and a heating effect is applied to the sleeve member such that the sleeve member deforms to seal against the first filler material.

Abstract: A method of assembling a piezoelectric actuator arrangement (10) comprises the steps of providing a piezoelectric element (12) having first and second ends and arranging the piezoelectric element (12) within a sleeve member (20) such that the inner surface of the sleeve member (20) defines, together with the outer surface of the piezoelectric element (12), a chamber (24) for receiving a first filler material (30). The first filler material (30) is injected into the chamber (24) and a heating effect is applied to the sleeve member (20) such that the sleeve member (20) deforms to seal against the first filler material (30).

Abstract: A pneumatically actuated magnetic workpiece holder comprising a housing having a contact surface for contacting a workpiece to be held, and a magnet assembly translationally disposed in the housing, the magnet assembly comprising a plurality of permanent magnets arranged so that adjacent magnets are of opposite polarities. The housing is adapted for fluid communication with a pneumatic supply. The magnet assembly is biased towards an operative position, according to which the magnet assembly is sufficiently near the contact surface to exert on a workpiece an attractive force sufficient for holding the workpiece in contact with the workpiece holder, and is translationally positionable by pneumatic pressure towards an inoperative position, according to which the magnet assembly is sufficiently distant from the contact surface so as to be unable to exert on the workpiece an attractive force sufficient for holding the workpiece in contact with the workpiece holder.

Abstract: An actuator arrangement comprising a piezoelectric element formed from a piezoelectric material, a first end of the piezoelectric element cooperating with an input piston member slidable within a bore. A surface associated with the input piston member defines, in part, a control chamber for fluid, fluid pressure within the control chamber acting on a surface associated with an output piston member. The fluid within the control chamber is substantially incompressible such that, in use, movement of the input piston member is transmitted to the output piston member, the piezoelectric element being arranged within a second chamber for fluid such that fluid pressure within the second chamber exerts a force on at least a part of the surface of the piezoelectric element which serves to oppose the load exerted on the piezoelectric element due to fluid pressure within the control chamber, thereby suppressing distortions in the piezoelectric material.

Abstract: A fuel injector comprising a valve needle which is slidable within a bore and engageable with a seating to control fuel delivery through first and second outlet openings. The valve needle is moveable between a closed position and first and second fuel injecting positions. The fuel injector further comprises a fuel supply passage for supplying fuel under pressure to the bore and a control chamber which is arranged to receive fuel from the fuel passage, in use. The valve needle is acted upon in use by a force due to fuel pressure within the control chamber. An actuator arrangement controls fuel pressure within the control chamber, and a damping means are provided for damping movement of the valve needle away from the seating into the first or second fuel injecting position. The supply passage for fuel may be provided with a restricted flow passage which serves to limit the amplitude of pressure waves within the supply passage.

Abstract: A method is provided for detecting injection events in a piezoelectric actuated fuel injector. The method comprises the steps of: (a) providing a piezoelectric element for actuating the injector valve; (b) applying a voltage to the piezoelectric element, thereby actuating the injector valve; and (c) monitoring at least one of the voltage or current associated with the piezoelectric element, wherein changes in voltage or current are indicative of injection events in the fuel injector.

Abstract: A piezoelectrically actuable fuel injector comprising an accumulator volume within which a piezoelectric stack is arranged, the accumulator volume being arranged to receive fuel from a source of pressurized fuel, in use. The piezoelectric stack carrying an end member which engages a surface associated with a piston member so as to apply a retracting force to the piston member upon a reduction in the axial length of the piezoelectric stack, the piston member being operable to control fuel pressure within a control chamber. A volume is defined between the end member and the surface associated with the piston member. The volume is provided with a vent arrangement to permit fuel within the volume to flow to a low pressure drain.

Abstract: A method and system for resolving error or erasure in binary data streams read back using MR heads from a cyclic, multitracked recording medium. The method assesses whether an erasure or error was coincident with a thermal asperity. If the coincidence occurred, the method branches to and executes an ordered list of data recovery procedures tuned to thermal asperity. This list emphasizes early use of burst ECC correction and alteration of MR head and read channel attributes.

Abstract: A fuel injector comprises a valve needle biased by a spring towards a seating. The spring engages a spring abutment member which is moveable with a piston member. The spring abutment member defines, with a member carried by the needle, a damping chamber which communicates through a restricted passage with a low pressure drain to damp movement of the needle relative to the piston member.

Abstract: A fuel injection system comprises a pumping plunger slidable within a bore and arranged to supply fuel to an injector nozzle. A spill valve communicates with the bore to control the fuel pressure applied to the nozzle. The nozzle includes a valve member biased into engagement with a seating by a spring, the spring engaging a piston member at least part of the end of which remote from the spring is exposed to the fuel pressure in the bore. The spill valve includes a flow connection which communicates by way of a restrictor with a drain. The restrictor is formed by the piston member and cylinder within which the piston member is slidable.