Abstract: A fuel injector includes an injector body with a bore; an injector needle located within the bore and engageable with a needle seat to control fuel injection through an injector outlet; an armature member, the armature member being engageable with an armature seat on the injector needle, the injector needle in part and the armature member in part defining a control chamber; an actuator arrangement arranged to control fuel pressure within the control chamber such that fuel pressure variations within the control chamber controls movement of the injector needle relative to the needle seat wherein the actuator arrangement is arranged to be capable of moving the armature member from a seated position in which it engages the armature seat to an unseated position in which the armature member has moved relative to the armature seat in order to bring the control chamber into fluid communication with a low pressure drain.

Abstract: A fuel injector includes control valve for controlling fuel pressure in a control chamber. The control valve includes a valve seat; and a valve member having a valve face for cooperating with the valve seat to control fuel pressure in the control chamber. A return line is provided for returning fuel from the control chamber. An armature connected to the valve member and an actuator is provided for actuating the armature. The armature is disposed in an armature chamber. A deflector is provided in the armature chamber to form a first sub-chamber and a second sub-chamber. The first and second sub-chambers are in fluid communication with each other via a first aperture. A pressure differential is established between the first and second sub-chambers when the valve face lifts from the valve seat promoting the flow of fuel from the second sub-chamber into the first sub-chamber through the first aperture.

Abstract: A fuel injector includes control valve for controlling fuel pressure in a control chamber. The control valve includes a valve seat; and a valve member having a valve face for cooperating with the valve seat to control fuel pressure in the control chamber. A return line is provided for returning fuel from the control chamber. An armature connected to the valve member and an actuator is provided for actuating the armature. The armature is disposed in an armature chamber. A deflector is provided in the armature chamber to form a first sub-chamber and a second sub-chamber. The first and second sub-chambers are in fluid communication with each other via a first aperture. A pressure differential is established between the first and second sub-chambers when the valve face lifts from the valve seat promoting the flow of fuel from the second sub-chamber into the first sub-chamber through the first aperture.

Abstract: A fuel injector includes an injector body with a bore; an injector needle located within the bore and engageable with a needle seat to control fuel injection through an injector outlet; an armature member, the armature member being engageable with an armature seat; on the injector needle, the injector needle in part and the armature member in part defining a control chamber; an actuator arrangement arranged to control fuel pressure within the control chamber such that fuel pressure variations within the control chamber controls movement of the injector needle relative to the needle seat wherein the actuator arrangement is arranged to be capable of moving the armature member from a seated position in which it engages the armature seat to an unseated position in which the armature member has moved relative to the armature seat in order to bring the control chamber into fluid communication with a low pressure drain.

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.