Abstract: A casing for encapsulation of an electrical component, for example a piezoelectric actuator, comprising an outer layer of a semipermeable material and an inner layer comprising a chemically active, hydrophilic substance that chemically combines with water to form a compound.

Abstract: A method of operating a fuel injector including a piezoelectric actuator having a stack of piezoelectric elements, and wherein in use the injector communicates with a fuel rail, the method comprises: applying a discharge current to the actuator for a discharge period so as to discharge the stack from a first differential voltage level across the stack to a second differential voltage level across the stack; maintaining the second differential voltage level for a period of time; and applying a charge current to the actuator for a charge period so as to charge the stack from the second differential voltage level to a third differential voltage level; wherein the third differential voltage level is selected in dependence on at least two engine parameters, the at least two engine parameters selected from: rail pressure; the electric pulse time; and the piezoelectric stack temperature.

Abstract: A method for estimating the composition of a fuel within an engine, comprises performing the following steps under ambient conditions: (a?) determining the ambient temperature of the fuel; (a) monitoring the fuel pressure inside a fuel rail of the engine over a period of time; (b) calculating at least one frequency component of the change in fuel pressure; (c) calculating the speed of sound transmission c on the basis of the at least one frequency component; and (d) estimating the composition of the fuel on the basis of the calculated speed of sound transmission at said ambient temperature. Suitably, the speed of sound transmission in the fuel is calculated using the equation: c=f?, where the wavelength ? of the standing wave with frequency f is 2L, where L is the length of the fuel rail. Also described are methods for estimating the temperature of the fuel at a non-ambient temperature, and determining a fuels physical properties.

Abstract: The invention relates to a fuel injection system of the common rail type having a rail body comprising a central bore and one or more outlet bores in fluid communication with the central bore for communicating with a respective fuel injector. The outer circumference of the rail body is substantially oval in cross-section and is thicker in cross-section in a direction substantially perpendicular to the outlet bore axis as compared to the thickness in cross-section substantially parallel to the outlet bore axis. By increasing the thickness of the rail body in this way, stresses at the intersection of the intersection of the central bore with the outlet holes may be reduced by up to 10% or more, thereby increasing the acceptable cycled running pressure of the system.

Abstract: A fluid delivery system for delivering a metered dose of fluid from a supply tank (28) to a downstream chamber or vessel (10), comprises a pump apparatus (20) comprising a pump plunger (32) which is operable to perform a pumping stroke under the control of an electromagnetic actuator (36), including a solenoid (36a), to effect delivery of the fluid and a control unit (24) for supplying an input signal (58) to the solenoid (36a) to initiate a current flow to the solenoid (36a) and thereby initiate movement of the pump plunger (32). An electronic device (54) provides an output signal to indicate that movement of the pump plunger has stopped at the end of the pumping stroke, and a timer determines a time difference between the input signal (58) being supplied to the solenoid (36a) and the output signal being output by the electronic device (54).

Abstract: A piezoelectric actuator (2) comprising a stack of one or more piezoelectric elements (4) defining an external surface, and passivation means (20) applied to the external surface of the stack, wherein the passivation means (20) includes a self-supporting polyimide material (20b) (e.g. in the form of a layer, film or membrane).

Abstract: An injection nozzle for injecting a fluid, the injection nozzle including a nozzle body and a nozzle hole defining a flow passage for fluid, the flow passage including passage walls and the nozzle hole having an inlet in fluid communication via the flow passage with an outlet wherein, the inlet is larger than the output and for at least one section through the inlet and outlet along the flow passage that the nozzle hole is defined, for all distances x within a substantial length of the flow passage, by the condition: |(dS/dx)|>45 microns/millimeter, where S=passage wall separation and x is the distance from the inlet.

Abstract: A fuel injection system for an internal combustion engine comprises a plurality of pumps arranged to supply respective flows of pressurized fuel to a common accumulator volume that supplies the pressurized fuel in turn to a plurality of fuel injectors. An engine control unit controls the flow rate of pressurized fuel into the accumulator volume in response to engine load. The flow rate of pressurized fuel from at least one pump of the plurality is dependent upon engine speed; whereas at least one other pump of the plurality comprises a fuel output control responsive to the engine control unit enabling the flow rate of pressurized fuel from that pump to be varied independently of engine speed. In this way, the engine control unit controls the aggregate flow rate of pressurized fuel from the pumps into the accumulator volume, while controlling only one of the pumps. This reduces the cost of control apparatus and allows greater freedom of pump selection and flow circuit design.

Abstract: A fluid accumulator arrangement suitable for use with a compression ignition internal-combustion engine comprising a first storage volume, a second storage volume, and valve means fluidly connected between the first storage volume and the second storage volume. In one embodiment, the valve means is a three-way control valve wherein, in a first position, the first storage volume communicates with the second storage volume, in a second position the first storage volume is isolated from the second storage volume and, in a third position, one of the first or second storage volumes communicates with a low pressure drain. The arrangement may also include control means to operate the valve means in accordance with predetermined control strategies.

Abstract: A method for manufacturing a piezoelectric actuator, the method comprising: co-extruding alternating strips of a high permittivity material and a low permittivity material to form a green tape comprising said alternating strips of said high permittivity material and said low permittivity material; cutting said green tape to form a plurality of sheets, each sheet comprising a high permittivity region and at least two low permittivity regions adjacent to the high permittivity region; applying at least one conductive region to each one of two or more of the sheets to overly the high permittivity region and to leave exposed at least one low permittivity region; and stacking a plurality of sheets to form an actuator stack comprising adjacent sheets, wherein the or each conductive region on each sheet is offset with respect to a conductive region on a different sheet within the actuator stack.

Abstract: A method of operating a fuel injector having a piezoelectric actuator that is operable by applying an electrical drive pulse thereto to activate and deactivate the injector. The method includes monitoring an electrical characteristic of the actuator during a predetermined time period, determining a time-domain data sample corresponding to the monitored electrical characteristic during the predetermined time period, determining a frequency spectrum signature corresponding to the time-domain data sample, and comparing the frequency spectrum signature of the monitored electrical characteristic to a predetermined frequency spectrum signature indicative of an injector event.

Abstract: A fuel injector mountable with respect to a combustion chamber for delivering fuel thereto, the combustion chamber comprising a chamber ceiling and a chamber wall, the fuel injector comprising a nozzle body having a primary nozzle axis; a first outlet opening having a first axis; a second outlet opening having a second axis; and means for controlling fuel delivery through the first and second outlet openings. The means for controlling fuel delivery comprises an inner valve needle and an outer valve needle, and is arranged to permit fuel delivery from only the first outlet opening, or through both the first and second outlet openings together. The first and second outlet openings are oriented such that, in use, when fuel delivery is permitted through only said first outlet opening, a first spray formation is injected along the first axis, the first spray formation reaching a first target distance below said chamber ceiling at a radial distance from the primary nozzle axis.

Abstract: A dosing device is provided that is suitable for administering a reagent into an exhaust chamber of an internal combustion engine. The device comprises a nozzle body and an insulating jacket wherein the jacket is mounted to the nozzle body at one or more mounting points, and wherein the dosing device is adapted to engage with a port located in the wall of an exhaust chamber. The insulating jacket defines a compartment, which can comprise an insulating material or can be substantially evacuated. The dosing device of the invention is advantageously insulated from the elevated temperatures in the surrounding environment, thereby allowing for the reagent to be maintained at an optimal working temperature range.

Abstract: A fuel injector comprising a nozzle having a nozzle needle which is moveable with respect to a first needle seat to control fuel delivery through a nozzle outlet. The injector includes a nozzle control valve for controlling fuel flow into a control chamber through a first passage to pressurise the control chamber, and for controlling fuel flow out of said control chamber through said first passage to depressurise the control chamber. Movement of the nozzle needle is controlled by fuel pressure within the control chamber, such that pressurising the control chamber causes the nozzle needle to be urged against the first needle seat to close the nozzle outlet, and depressurising the control chamber causes the nozzle needle to lift from the first needle seat to open the nozzle outlet. The nozzle needle defines, at least in part, a restricted passage through which fuel can flow into the control chamber as the control chamber depressurises.

Abstract: A fuel injector for use in an internal combustion engine comprises a first valve member and a second valve member, an injection control chamber for fuel, and a set of nozzle outlets; wherein actuation of the second valve member controls the fuel pressure within the injection control chamber, and actuation of the first valve member is regulated by the fuel pressure within the injection control chamber; and wherein the fuel injector is arranged such that actuation of the second valve member establishes a fuel flow path between the injection control chamber and the set of nozzle outlets. The first valve member may be provided with a first valve bore within which the second valve member is received. An injection nozzle and a method of operating a fuel injector are also described.

Abstract: A method of identifying an individual short circuit fuel injector, within an injector bank of an engine comprising a plurality of fuel injectors. Each fuel injector has a piezoelectric actuator and an associated injector select switch forming part of an injector drive circuit. The method comprises: (i) charging all of the piezoelectric actuators of the plurality of fuel injectors within the injector bank during a charge phase; (ii) at the end of the charge phase waiting for a delay period; and (iii) subsequently closing an injector select switch of a fuel injector to select said fuel injector. The method further comprises: (iv) determining a stack voltage present on terminals of the piezoelectric actuator of the selected fuel injector and storing the stack voltage in a data store. The stack voltage is indicative of an amount of charge present on the selected injector at the end of the delay period.

Abstract: A fuel pressure regulation system for a compression ignition diesel engine. The system comprises a fuel supply line connected to an inlet of a transfer pump and a transfer pressure fuel line connected between the transfer pump outlet and the high pressure fuel pump inlet. A fuel filter is positioned in the transfer pressure fuel line and a fuel spill line fluidly connects a fuel pressure regulator to the transfer pressure fuel line at a point between the transfer pump outlet and the fuel filter. A fuel return line is connected between the fuel pressure regulator and the fuel supply line and a control fuel line is connected between the fuel pressure regulator and the transfer pressure fuel line. The fuel pressure regulator comprises a bore within which is located a valve member moveable from a non-regulating position of the fuel pressure regulator to a regulating position of the fuel pressure regulator.

Abstract: A fuel lance assembly for an engine comprises: a fuel lance to be received in a passage provided in a cylinder head and a connection arrangement comprising an inlet adapter for securing the fuel lance within the passage. The fuel lance comprises a tubular member of constant external diameter, arranged to be received, in use, within the passage and having a first end being shaped for cooperation with a seating surface of a fuel injector of the engine, and a second end being shaped for cooperation with the inlet adapter, and being provided with a bore therethrough to define a fuel flow path between the first end and the second end of the fuel lance. The inlet adapter is provided with an attachment system for engaging a compatible attachment system of the cylinder head, and has a proximal region for receiving a high pressure fuel pipe, and wherein the inlet adapter has a distal region provided with an opening being adapted to receive the second end of the fuel lance.

Abstract: A pump head suitable for use in a fuel pump for a common rail fuel injection system, comprises a pump head housing defining a plunger bore and a pumping chamber. Fuel is pressurized within the pumping chamber by a plunger reciprocating within the plunger bore. The pump head housing includes an inlet valve arrangement for controlling fuel flow into the pumping chamber. The inlet valve arrangement includes a valve member movable between open and closed positions in response to fuel pressure within a gallery. The gallery communicates with an external chamber defined by a closure means externally mounted to the pump head housing. In use, the gallery communicates with a source of low-pressure fuel via the external chamber. The pump head housing has a projection which locates the closure member on the pump head housing.

Abstract: A clip for securing a sleeve to the body of a piezoelectric actuator in an actuator assembly, the clip taking the form of a band comprising first and second axially spaced ring-like members joined by a plurality of inwardly facing substantially arch shaped sections, the arch shaped sections defining the minimum inner diameter of the band, whereby axial displacement of the ring-like members way from one another causes flexing of the arch shaped sections to increase the minimum inner diameter of the band while axial displacement of the ring-like members towards one another causes flexing of the arch shaped sections to reduce the minimum inner diameter of the band thereby, when in use, to increase a clamping force applied to the sleeve.