Abstract: A fuel system is described which comprises a high pressure fuel pump arranged to supply fuel under pressure to a plurality of injectors. A backleak connection line is arranged to return fuel from the injectors to a fuel reservoir. A venturi pump is connected to the backleak connection line and is arranged to draw fuel from the line to reduce the fuel pressure therein.

Abstract: Fuel pump for delivering high pressure fuel to a fuel injection system of an internal combustion engine is provided. The fuel pump has a body, a drive shaft rotatably mounted in the body, at least one cam on the drive shaft, a plurality of pumping plungers mounted in the body for movement in the radial direction relative to the axis of rotation of the drive shaft, a pumping chamber defined radially outwardly of each plunger, and a delivery valve associated with each pumping chamber. Each pumping plunger is mounted in a support member which provides sliding support for its associated plunger in the circumferential direction of the drive shaft over substantially the entire length of the plunger in all working positions thereof. Each plunger is coupled to at least one cam by a pin which is secured to the plunger and extends outwardly from the plunger through a slot which extends through the support member in the axial direction of the drive shaft.

Abstract: A valve arrangement is disclosed which comprises a valve member engageable with a seating. The valve member includes a relatively flexible region whereby damage to the valve arrangement, in use, can be reduced and the tolerance to manufacturing inaccuracies can be improved. The valve member is conveniently shaped so that the application of fuel at high pressure thereto biases the valve member towards the seating. A further arrangement is disclosed in which the valve member is permitted to move laterally to center the valve on its seating, the application of fuel to the valve member biasing the valve member towards its seating. Another arrangement is disclosed in which the position of the seating is adjustable.

Abstract: An injector is disclosed which comprises a valve needle moveable within a bore of a nozzle body. The valve needle is engageable with a seating, and downstream of the seating, the nozzle body and valve needle together define a chamber. Passages communicate with the chamber to supply fuel from the chamber to outlet ports. The ports are located so as to be covered by the valve needle when the needle engages its seating, movement of the needle away from its seating beyond a predetermined distance uncovering the ports.

Abstract: This invention relates to a fuel pump, and more particularly to a fuel pump for delivering high pressure fuel to a fuel injection system of an internal combustion engine. A fuel pump is provided comprising coupling means (30) mechanically coupling a first pump plunger (1) to a second drive means (14) and a second pump plunger (11) to a first drive means (4) whereby, when the first pump plunger (1) is driven by the first drive means (4) from bottom dead center to top dead center, the second pump plunger (11) is driven by the coupling means (30) from top dead center to bottom dead center, and as the second pump plunger (11) is driven from bottom dead center to top dead center by the second drive means (14), the first pump plunger (1) is driven from top dead center to bottom dead enter by the coupling means (30).

Abstract: An injection nozzle comprises a valve needle engageable with a seating. The needle includes a surface arranged such that when the needle occupies a fully lifted position, part of the surface is exposed to the fuel pressure within a control chamber whilst a second part of the surface is exposed to the fuel pressure within a second chamber. Independent restricted passages provide communication between the control and second chambers and a supply line. A control valve communicates with the second chamber to control operation of the injection nozzle. The control valve is actuated by an electromagnetic actuator having a core arrangement--armature air gap of tapering axial length.

Abstract: A pump/injector arrangement comprises a pump including a pump chamber arranged to communicate through a fuel line with an injector. A valve is provided within the injector to control whether or not fuel is able to flow from the fuel line to a control chamber. The control chamber communicates with a low pressure reservoir through a restricted passage. A by-pass is provided to permit fuel to flow from the reservoir by-passing the restricted passage.

Abstract: A valve arrangement comprises a piezo electric member arranged to control fuel flow through an orifice, the piezo electric member being operable to flex away from the orifice to allow an increased rate of fuel flow therethrough. The piezo electric member is also engageable with a valve member of a pressure relieving valve to control lifting of the valve member from a seating.

Abstract: A fuel injection nozzle is disclosed which comprises a valve needle slidable along a first axis to control fuel delivery by the nozzle, and an actuator including a member moveable along a second axis to control movement of the valve needle. The first and second axes are offset from one another, thus the wall of a body housing the valve needle and actuator includes a region of relatively great thickness.

Abstract: A valve arrangement is disclosed which comprises a body provided with a bore, first, second and third passages communicating with the bore at axially spaced locations. A valve member is engageable with a first seat to control fluid flow between the first and second passages. A valve element is engageable with a second seat to control fluid flow between the second and third passages. A spring biasses the valve element away from the second seat, and an extensible member interconnects the valve element and the valve member. The valve member is thus biased toward the first seat.

Abstract: A pressure regulation valve is disclosed which comprises a housing including first and second ports, a support for slidably supporting a tubular member defining a valve seat against which a valve element is engageable. The tubular member and valve element are spring biased into engagement with one another. In use, the application of pressurized fuel to the first port pushes the tubular member against the stop, the valve element being able to leave the valve seat in order to permit fuel flow through the valve. If the second port is at a higher pressure than the first port, the valve element moves into engagement with the valve seat, the application of a high pressure resulting in the valve element and tubular member moving until the valve element engages the support, further movement of the tubular member permitting fuel flow through the valve from the second port to the first port.

Abstract: A fuel supply apparatus for supplying fuel to a compression ignition engine comprising a rotary distributor member having a delivery passage which can register in turn with outlet ports connected to the injection nozzles of the engine. Fuel is supplied to the delivery passage from an accumulator under the control of a valve. The accumulator is charged with fuel by means of a high pressure pump which is a cam actuated pump and fuel is supplied to the high pressure pump by a low pressure pump. A valve is provided to control the output pressure of the low pressure pump so that the amount of fuel supplied to the high pressure pump can be varied for the purpose of controlling the fuel pressure within the accumulator. This pressure is sensed by a transducer which supplies a signal to a control system which controls the flow of electric current in the valve.

Abstract: A rotary distributor fuel injection pump includes a pumping plunger housed in a bore and has a spill valve member integrally formed with an actuator piston contained in a cylinder. High pressure fuel from the bore can be admitted to the one end of the cylinder to move the actuator piston and valve member away from the seating by opening an on/off valve. When the spilled fuel has been returned to the bore further fuel flows to the bore by way of the on/off valve and this fuel flows to the on/off valve through a non-return valve from a source of fuel under pressure.

Abstract: An engine fuel system includes an accumulator chamber in which fuel is stored at high pressure and a three way valve having two settings in the first of which when a valve actuator is energised fuel flows from the accumulator chamber to a fuel injection nozzle and in the second of which when the actuator is de-energised fuel flows from the supply line of the nozzle to a drain. The valve includes a valve member directly coupled to the actuator and controlling the flow of fuel from the accumulator chamber to the nozzle, and a valve element which is resiliently coupled to the valve member and controls the flow of fuel from the line to the drain. The valve member and valve element cooperate with respective seatings and when the actuator is de-energised the valve element can move away from its seating against the action of the resilient coupling to allow a rapid reduction of fuel pressure in the line.

Abstract: A fuel pumping apparatus comprises a pumping plunger reciprocable in a bore to supply fuel to the cylinders of an associated engine. A spill valve arrangement is provided to control fuel delivery, the spill valve arrangement including a valve member coupled to a first piston which is slidable within a first cylinder. Passage means are provided in the first piston interconnecting the ends of the first cylinder permitting restricted flow therebetween. A second piston slidable within a second cylinder is arranged to engage an end of the first piston, a spring biasing the second piston towards the first piston and biasing the valve member into engagement with a valve seat. In use, at high engine speed the pressure of fuel between the pistons increases, separating the pistons permitting fuel to escape through a passage provided in the second piston. Such an escape of fuel results in additional fresh, cool, fuel being drawn into the pumping apparatus thus cooling the pumping apparatus.