Abstract: A fault detection method for detecting short circuit faults in an injector arrangement at engine start-up. The injector arrangement comprises one or more piezoelectric fuel injectors, which are connected in a drive circuit. In one aspect of the invention, the potential at a bias point in the drive circuit is determined and compared with a predicted voltage. A short circuit fault signal is generated if the potential at the bias point is not within a predetermined tolerance voltage of the predicted voltage. In another aspect of the invention, a first charge pulse is applied to the injectors to charge the injectors. A discharge current path is provided during a delay period following the first charge pulse by closing a discharge switch. A faulty injector will discharge through the discharge current path during the delay period. A second charge pulse is applied to the injectors following the delay period.

Abstract: An armature for a solenoid actuator is disclosed. The armature comprises a first face comprising a recess suitable for receiving a biasing spring in use of the armature; a second face opposite the first face; and fluid communication means for providing a fluid flow path through the armature between the recess and the second face in use of the armature. The first face is uninterrupted by the fluid communication means. The invention reduces the risk of cavitation damage during operation of the actuator. In one application, the actuator is used in a fluid pump for a selective catalytic reduction system.

Abstract: A fuel injector for use in an internal combustion engine, comprising a nozzle body being provided with a nozzle bore and at least one set of one or more outlets for fluid, an outer valve member received within the nozzle bore and being engageable with a first seating region of the nozzle body to control the flow of a first fluid from a first delivery chamber, the outer valve member being provided with an outer valve bore, and an inner valve member received within the outer valve bore and being engageable with a second seating region of the nozzle body to control the flow of a second fluid from a second delivery chamber. In various embodiments, the fuel injector can be arranged to allow the first and second fluids to be injected separately and/or together. In one embodiment, the first and second fluids can be mixed within the injector before injection.

Abstract: The present invention relates to a connector assembly comprising a connector unit mounted in a housing. The connector unit has a mounting portion, at least one electrical terminal and a body portion having a locking tab. The housing has a first longitudinal axis X1 and the body portion has a second longitudinal axis X2. The first longitudinal axis X1 and the second longitudinal axis X2 are offset from each other to enable the tip of the locking tab to be radially inset. An axial press tool can be used to mount the connector unit mechanically in the housing. The present invention also relates to a method of assembling a connector assembly.

Abstract: A fault detector for detecting valve movement of a valve in a fuel injector of an engine system, the valve includes an electromagnetic actuator arranged to move the valve between first and second valve positions, the engine system includes a sensor for sensing a current through the actuator. The detector includes a controller arranged to control the sensor; receive sensor data related to the current through the actuator; analyze the received data for current discontinuities; and output a valve movement signal dependent upon the current discontinuities. The controller is arranged to sense current during a finite sampling window, move the sampling window from a first window position to a later window position for one or more subsequent injection events; determine a new sampling window position on based a valve movement signal output the two preceding windows; and feedback the new sampling window position for a subsequent injection event.

Abstract: A fuel injector for an internal combustion engine, the fuel injector comprising an injector body, a fuel supply passage defined in the injector body, the fuel supply passage containing fuel under high pressure in use of the injector, a pressure sensor for measuring the pressure of fuel in the passage in use, wherein the pressure sensor is situated within the injector body and is separated from fuel in the passage in use, and a method of fuel injection, comprising constructing an hydraulic behavior profile by fuel pressure measurement, using the hydraulic behavior profile to predict fuel pressure that will prevail in a fuel injector during an injection event, and supplying a control signal to the fuel injector to control the amount of fuel injected during the injection event in accordance with the predicted fuel pressure. By predicting the fuel pressure that will prevail during an injection event, the fuel delivered during the injection event can be accurately controlled.

Abstract: A fuel injector for use in an internal combustion engine, the fuel injector comprising: a valve needle which is engageable with a valve needle seat to control fuel injection through an injector outlet; an actuator arrangement arranged to control fuel pressure within a control chamber, a surface associated with the valve needle being exposed to fuel pressure within the control chamber such that fuel pressure variations within the control chamber control movement of the valve needle relative to the valve needle seat; damping means for damping opening movement of the valve member, the damping means comprising a damper chamber and the damping means being arranged such that fuel pressure variations within the damper chamber damp opening movement of the valve member wherein the damping means is arranged such that in use there is a through flow of fuel through the damper chamber.

Abstract: A method and apparatus for controlling a fuel pump assembly comprising a plurality of pump elements for delivering fuel at high pressure to a rail volume, each of the pump elements comprising a plunger which is driven by an associated cam to perform at least one pumping event per engine revolution and a control valve for controlling fuel flow into and/or out of the pump chamber. Each pumping event corresponds to an associated cam lobe of the associated cam. The method comprises, for each pumping event of each pump element, controlling the control valve of said pump element in response to an output control signal derived from at least one previous pumping event. The output control signal is derived by measuring fuel pressure within the rail volume to derive a measured rail pressure value; and comparing the measured rail pressure value with a demanded rail pressure value to derive a rail pressure error.

Abstract: A fuel injector for a compression ignition internal combustion engine which comprises a fuel injection valve having an injection valve member which is moveable in use, under the influence of fuel pressure within an injection valve member control chamber acting upon it, between a closed position and an open position. The fuel injector further comprises a high pressure fuel supply passage to the injection valve member control chamber, and an actuator operable to open and close a discharge valve connected between the injection valve member control chamber and a fuel outlet passage to a low pressure reservoir or drain. A shut-off valve is provided in the high pressure fuel supply passage and the shut-off valve has a shut-off valve member which is moveable in use, under the influence of fuel pressure within a shut-off valve member control chamber acting upon it, between a closed position and an open position.

Abstract: A control valve arrangement for use in controlling fuel pressure within a control chamber (30) includes a control valve member (32) which is movable between a first position in which the control chamber (30) communicates with a source of high pressure fuel, and a second position in which the control chamber (30) communicates with a low pressure fuel drain and communication between the control chamber (30) and the source of high pressure fuel is broken. The control valve arrangement also includes restricted flow means (55, 70, 86) for restricting the rate of flow of fuel from the control chamber (30) to the low pressure fuel drain when the control valve member (32) is moved from the first position to the second position.

Abstract: The invention relates to a fuel injection valve for internal combustion engines, comprising a valve body (1), with a drilling (3) embodied therein and defined at the combustion chamber end thereof by a conical valve seat (18) from which at least one injection opening (20) leads. A hollow valve needle (8) is arranged in the drilling (3) such as to be displaced longitudinally, comprising a valve sealing surface (35) at the end thereof facing the valve seat (18). A first sealing region (31; 34) and a second sealing region (32; 46; 48) are embodied on the valve sealing surface (35), whereby, on contact of the hollow valve needle (8) on the valve seat (18), the first sealing region (31; 34) provides a seal upstream of the at least one injection opening (20) and the second sealing region (32; 46; 48) downstream thereof.

Abstract: A method for controlling the displacement of a stack of a piezoelectric actuator for use in a fuel injector comprises determining a desired amount of charge (?Q) to be added or removed from the stack. The method further comprises determining an operating parameter of the fuel system and selecting a drive current level (PO, SO) and a drive time (topen, tclose) in accordance with the desired amount of charge (?Q) and the operating parameter, and driving the drive current through the stack for the drive time (topen, tclose) in order to add or remove the desired amount of charge (?Q).

Abstract: A method of operating a fuel injector having a piezoelectric actuator operable by applying a drive pulse thereto, wherein the drive pulse has a frequency domain signature. The method includes i) determining at least one resonant frequency of an injector installation in which the injector is received, in use, and ii) modifying the drive pulse such that a maximum of the frequency domain signature thereof is remote from the determined resonant frequency of the injector installation.

Abstract: A piezoelectric actuator comprising a stack of piezoelectric layers formed from a piezoelectric material, a plurality of internal electrodes disposed throughout the stack to define active regions of the piezoelectric material therebetween which are responsive to a voltage applied across two or more groups of the internal electrodes in use, an insulating arrangement which at least partially covers at least one surface of the stack to define a piezoelectric/insulator interface, and two or more side electrodes to connect with the two or more groups of the internal electrodes.

Abstract: The invention provides a method for determining the angular position of a pump shaft relative to a pump body. The method comprises: providing the pump shaft with a first locating feature; providing the pump shaft with a second locating feature; providing a measurement device provided with a measurement member; engaging the measurement member with the first locating feature and determining a first distance between the first locating feature and a reference feature provided on the measurement device; engaging the measurement member with the second locating feature and determining a second distance between the second locating feature and a reference feature provided on the measurement device; and determining the difference between the first and second distances to provide an indication of the angular position of the pump shaft relative to the pump body. The invention also provides apparatus suitable for performing the above method.

Abstract: A detector for detecting the operational status of one or more fuel pumps in a fuel system of a vehicle, the system comprising an accumulator volume for storing high pressure fuel, one or more injectors arranged in fluid communication with the accumulator volume and one or more high pressure fuel pumps arranged in fluid communication with the accumulator volume so as to supply high pressure fuel thereto, the operation of the one or more fuel pumps being controlled by a filling pulse signal from a control means, the detector comprising inputs for receiving data representing at least one current system parameter; processing means arranged to compare the at least one current system parameter against one or more predetermined system parameters in order to identify the operational status of the one or more fuel pumps.

Abstract: A pump is provided for pumping two or more different fluids. The pump comprises a body having a longitudinal bore and at least first and second inlets selectively communicating with and providing passage to the bore via non-return valves. A plunger is mounted for reciprocation within the bore and at least one piston is also mounted for reciprocation within the bore so as to permit at least one type of fluid to pass into the bore through one or both inlets.

Abstract: A method of detecting faults in an injector arrangement in an engine. The injector arrangement comprises at least one fuel injector having a piezoelectric actuator, and the method comprises: charging the piezoelectric actuator during a charge phase (tC); attempting to recharge the piezoelectric actuator during a test phase (tT) which commences after a time interval (?t) following the end of the charge phase (tC); sensing a current (IS) that flows through the piezoelectric actuator during the test phase (tT); and generating a short circuit fault signal if the sensed current (IS) reaches a first predetermined threshold current (ISC) which is indicative of a short circuit in the piezoelectric actuator.

Abstract: A fuel delivery system for an internal combustion engine, the system comprising a common rail fuel reservoir having a primary rail axis and comprising a plurality of outlets at spaced locations along said rail axis and a plurality of fuel injectors arranged at spaced locations with respect to said rail axis. Each injector comprises an injector inlet, said plurality of fuel injectors defining first and second groups of injectors.

Abstract: A piezoelectric actuator for use in a fuel injector, the actuator comprising a stack of one or more piezoelectric elements for receipt within an accumulator chamber of the injector, distribution electrode means for generating an electric field within the stack and an electrical connector arrangement including a body member defining an external boundary and including a base portion and a stem portion projecting from the base portion. The base portion defines a base end face for abutment with an adjacent end face associated with the stack. Terminal means are provided for connection with an external power supply. The terminal means includes first and second terminal members disposed internal to the external boundary of the body member. The first and second terminal members are arranged side by side and disposed internal to the external boundary of the body member.