Abstract: A fault detector for detecting valve movement of a valve in a fuel injector of an engine system, the valve comprising an electromagnetic actuator arranged to move the valve between first and second valve positions during a valve cycle, the engine system comprising a sensor for sensing a current through the actuator. The detector comprises a controller arranged to control the sensor; inputs for receiving from the sensor data related to the current through the actuator; a processor arranged to analyze the received data for current discontinuities; and outputs for outputting a valve movement signal in dependence upon the current discontinuities determined by the processor.

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 control method for a fuel injection system having a spill valve (20), a nozzle control valve (22) and a valve needle (12) which is engageable with a seating to control fuel injection, wherein the method comprises applying a first drive current signal (30) to the spill valve (22) to move the spill valve (22) into a closed state and applying a second drive current signal (40) to the nozzle control valve (22) to move the nozzle control valve (22) to an open state, thereby to lift the valve needle (12) from the seating to initiate a main injection of fuel. The first drive current signal (30) is modified so as to move the spill valve (20) to an open state during “a spill valve opening period” during which the second drive current signal (40) is modified to move the nozzle control to valve (22) from the open state to a closed state. As a result the valve needle (12) is seated to terminate the main injection of fuel.

Abstract: A cam arrangement for use with a high pressure fuel pump arrangement for delivering fuel to an associated engine, the cam arrangement including at least two cams (28) that are mounted, in use, upon an engine camshaft and each of which is arranged to drive a respective pumping plunger (16) of the fuel pump arrangement, wherein each plunger is driven to perform a pumping stroke, against return biasing means (32), during which fuel within a pump chamber (22) associated with each plunger is pressurised, and whereby said return biasing means (32) effects a plunger return stroke, and wherein each cam (28) is oriented relative to the or each other cam and has a surface (50) shaped such that the associated plunger return stroke is interrupted to define at least one step of plunger movement that is substantially synchronous with the pumping stroke of another of the plungers (16) of the pump, thereby to reduce negative torque loading of the camshaft.

Abstract: An actuator arrangement for use in a fuel injector of an internal combustion engine includes an inner core (30) comprising a plurality of laminates (30a) and a first outer pole (32) for receiving at least a part of the inner core (30), wherein the inner core (30) and the outer pole (32) together define a first volume (46) for receiving a first electromagnetic winding. An injector is provided in which the actuator arrangement controls a valve arrangement, either a spill valve or a nozzle control valve, or both, so as to control injection by the injector.

Abstract: A fuel injector for use in an injector arrangement includes a fuel pump having a pump chamber and a spill valve controlling communication between pump chamber and a low pressure reservoir. The injector includes a valve needle which is engageable with a valve needle seating, a control chamber arranged such that the fuel pressure therein urges the valve needle towards the valve needle seating. A control valve is provided for controlling the fuel pressure within the control chamber. An actuator arrangement is arranged to control the operation of the control valve such that, when the actuator arrangement is de-energised, the control valve permits communication between the control chamber and the low pressure reservoir.

Abstract: A method of controlling an electromagnetically operated actuator for a valve arrangement. The valve arrangement is responsive to an actuator armature. The actuator has a winding and is preferably of the two-stage lift type. The method includes applying a first, low voltage to the actuator, using a first voltage source, to generate a relatively low rate of current increase through the actuator winding, thereby to impart a force to the armature to cause the armature to move relatively slowly from a rest position to a first intermediate position. The method also includes applying a second, higher voltage to the actuator, using a second voltage source coupled to the first voltage source through a regeneration path, to generate a relatively high rate of current increase through the actuator winding, thereby to impart a force to the armature to cause the armature to move relatively quickly from the first intermediate position to a second position.

Abstract: A fuel injector for use in an injector arrangement including a fuel pump having a pump chamber and a spill valve arrangement including a spill valve member which is engageable with a valve seating to control communication between the pump chamber and a low pressure drain. The fuel injector further comprises a valve needle which is engageable with a valve needle seating, a control chamber arranged such that the fuel pressure therein urges the valve needle towards its seating, a control valve arrangement, including a control valve member, for controlling the fuel pressure within the chamber, and an actuator arrangement for controlling movement of the spill valve member and the control valve member. The actuator arrangement comprises a double pole actuator having a first armature which is movable with the spill valve member and a single pole actuator having a second armature which is movable with the control valve member.

Abstract: A fuel injector comprises a valve needle spring biased towards a seating. The valve needle defines a thrust surface orientated such that the application of fuel under pressure thereto applies a force to the needle urging the needle away from the seating. A valve is provided to control the supply of fuel to the thrust surface.

Abstract: A fuel injector for use in an injector arrangement including a fuel pump having a pump chamber and a spill valve arrangement including a spill valve member which is engageable with a spill valve seating to control communication between the pump chamber and a low pressure drain. The fuel injector further comprises a valve needle which is engageable with a valve needle seating, a control chamber arranged such that the fuel pressure therein urges the valve needle towards its seating, a control valve arrangement, including a control valve member, for controlling the fuel pressure within the control chamber, and an actuator arrangement for controlling movement of the spill valve member and the control valve member. The actuator arrangement comprises a double pole actuator having a first armature which is movable with the spill valve member and a single pole actuator having a second armature which is movable with the control valve member.

Abstract: A fuel injector comprising a valve needle which is slidable within a bore, a surface associated with the valve needle defining, in part, a control chamber which communicates, through a restriction, with a supply passage. The fuel injector also includes an injection control valve controlling communication between the control chamber and a low pressure reservoir, and a drain valve controlling communication between the supply passage and the low pressure reservoir. The injection control valve and the drain valve include respective armatures moveable under the influence of a common electromagnetic actuator.

Abstract: A fuel injector comprising a valve needle biased by a spring into engagement with a seating, a surface associated with the valve needle being exposed to fuel pressure within a control chamber and restricted communication structure providing a restricted flow path between a supply passage and the control chamber. The fuel injector further comprises a drain valve controlling communication between the supply passage and a low pressure reservoir and an injection control valve controlling communication between the control chamber and the low pressure reservoir, the drain valve and the injection control valve being moveable under the control of a single electromagnetic actuator including an armature common to both valves.

Abstract: A fuel injector comprises a valve needle biased by a spring towards a seating. An electromagnetic actuator arrangement is operable to vary the magnitude of the biasing force applied to the needle by the spring.

Abstract: A spring assembly comprises a helical compression spring engaged between first and second spring abutments and a collar limiting movement of the second spring abutment away from the first spring abutment.

Abstract: A control valve of an engine fuel system includes a valve member which is coupled to an armature and is moved to engage a seating when a winding is energized. The current flow in the winding is first allowed to rise to a peak value to initiate movement of the armature and valve member at which time the winding is disconnected from the supply. The decay of current in the winding is controlled using two rates of current decay to ensure that the valve member moves into engagement with the seating with the minimum of bounce.

Abstract: An electromagnetic actuator assembly is described which comprises a stator housing having a slot extending across the diameter thereof. A stator core is located within the slot, the core carrying a coil. The core is conveniently shaped to permit the use of an increased diameter coil and to increase the area of the pole faces of the core.

Abstract: An injector comprises a body, a valve needle slidable within the body and biassed into engagement with a seating by a spring, a fuel supply line for supplying fuel to thrust surfaces provided on the valve needle to apply a force on the valve needle acting against the action of the spring, a drain valve operable to control communication between the supply line and a low pressure drain, a needle control valve controlling the fuel pressure within a control chamber defined, in part, by a surface of the valve needle or a component carried thereby oriented such that when high pressure fuel is applied to the control chamber, a force is applied to the valve needle in a direction assisting the spring, wherein the drain valve and the needle control valve are controlled by an electromagnetic actuator arrangement including a single armature, the needle control valve and the surface of the valve needle or component carried thereby defining part of the control chamber being of dimensions such that the needle control valve

Abstract: An engine fuel system including a solenoid actuated fuel control valve (16) which is energized to cause fuel delivery to the associated engine. The valve is initially closed to achieve pilot delivery of fuel by a high current pulse supplied to the solenoid winding (7) and is then allowed to open under the influence of a spring, the opening movement of the valve member being controlled by supplying current to the solenoid winding. Finally by supplying further current to the winding the valve member is closed to achieve closure of the valve for the main delivery of fuel.