Abstract: A fuel injector for an internal combustion engine comprising a nozzle body having at least one spray hole. The at least one spray hole has a hole entry on the inside of the nozzle body and a hole exit on the outside of the nozzle body. The spray hole is provided with a hole entry section which, starting from the hole entry, has a flow area which decreases from a relatively larger flow area at the hole entry to a relatively small flow area at the intersection between the end of the hole entry section and the start of a hole exit section. The hole exit section, starting from the intersection with the hole entry section, has a flow area which increases from a relatively small flow area at the intersection with the hole entry section to a relatively larger flow area at the hole exit.

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 an internal combustion engine, the fuel injector being of a type with an open-ended nozzle body adjoining an injector body. The interface between the nozzle body and the injector body is flat, to simplify manufacture, and they are aligned relative to each other using a compression element which is typically a sleeve that extends around them. The compression element also acts to apply a pre-compression to at least one of the bodies to enable the fuel injector to operate at higher fuel pressures than would otherwise be possible.

Abstract: A fuel injector for an internal combustion engine comprising a nozzle body having at least one spray hole. The at least one spray hole has a hole entry on the inside of the nozzle body and a hole exit on the outside of the nozzle body. The spray hole is provided with a hole entry section which, starting from the hole entry, has a flow area which decreases from a relatively larger flow area at the hole entry to a relatively small flow area at the intersection between the end of the hole entry section and the start of a hole exit section. The hole exit section, starting from the intersection with the hole entry section, has a flow area which increases from a relatively small flow area at the intersection with the hole entry section to a relatively larger flow area at the hole exit.

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: An injection nozzle for use in delivering fuel to a combustion space, the injection nozzle comprising a nozzle body, at least a part of which is provided with a first coating arranged so as to reduce the temperature of at least a part of the nozzle body, in use. The coating may have either a higher or lower thermal conductivity than the thermal conductivity of the nozzle body.

Abstract: A fuel injector comprising a nozzle body, a first outlet opening having an axis, a second outlet opening having an axis, and means for controlling fuel delivery through the first and second outlet openings. The axes of the first and second outlet openings are arranged so as to intersect one another downstream of the outlet openings such that, when fuel is delivered through both the first and second outlet openings, a combined spray formation is formed which is substantially equivalent to a single spray formation having been delivered from a single opening.

Abstract: An injection nozzle for use in delivering fuel to a combustion space, the injection nozzle comprising a nozzle body, at least a part of which is provided with a first coating arranged so as to reduce the temperature of at least a part of the nozzle body, in use. The coating may have either a higher or lower thermal conductivity than the thermal conductivity of the nozzle body.

Abstract: A fuel injector for delivering fuel to a combustion space comprises a valve needle which is movable within a bore provided in a nozzle body and which is engageable with a seating to control the supply of fuel from the bore. The injector further comprises a return flow passage for permitting fuel to escape from the bore to a low pressure drain upon initial movement of the valve needle away from its seating. The injector may include a cover member which defines, together with the nozzle body, a part of the return passage for fuel through which fuel flows, in use, to reduce the temperature of the nozzle body.

Abstract: A fuel injector comprising a nozzle body having a first bore defining first and second seatings and an outer valve member slidable within the first bore and engageable with the first seating to control fuel flow from a first outlet opening located downstream of the first seating. The outer valve member is provided with a through bore and an inner valve member is slidable within the through bore and is engageable with a second seating to control fuel flow from a second outlet opening. The through bore defines a step which is engageable with an enlarged region of the inner valve member, the through bore permitting, during fuel injector assembly, insertion of the inner valve member into the through bore through an end of the through bore remote from the first and second outlet openings. The invention also relates to a method of assembling such a fuel injector.

Abstract: A fuel injector comprising a valve needle slidable within a first bore, a surface associated with the valve needle being exposed to the fuel pressure within a first control chamber and movement of the valve needle away from the valve needle seating being limited by a moveable stop member. The stop member has a surface exposed to fuel pressure within a second control chamber. The fuel injector also includes a control valve arrangement for controlling the fuel pressure within the first and second control chambers to control movement of the valve needle and the stop member. The invention also relates to a fuel injector in which the control valve arrangement is arranged to permit the rate of valve needle movement away from the valve needle seating to be varied, in use.

Abstract: A fuel injector comprising a nozzle body provided with first and second outlet openings for fuel, a valve needle slidable within a valve needle bore defined in the nozzle body, the valve needle bore being shaped to define a seating with which the valve needle is engageable to control fuel flow to a chamber, the valve needle being provided with a flow passage communicating with the chamber, movement of the valve needle away from the seating into a first fuel injecting position permitting fuel delivery through the first outlet opening and whereby movement of the valve needle away from the seating into a second fuel injecting position causes fuel in the chamber to flow through the flow passage for delivery through the second outlet opening. The nozzle body may include an upper nozzle body part provided with a through bore and a lower nozzle body part provided with a blind bore, the lower nozzle body part being received in the through bore to close an open end thereof.

Abstract: A fuel injector comprises a first needle, and a second needle slidably within a passage formed in the first needle. The needles are engageable with respective seatings to control fuel delivery through respective groups of outlet openings. Load transmitting means are provided whereby movement of the first needle can be transmitted to the second needle. Also described is an injector in which a second needle is provided with formations defining an integral resilient biasing arrangement.

Abstract: A fuel injector of the outwardly opening type comprising a nozzle body provided with a first bore, a valve needle slidable within the bore and engageable with a seating to control the supply of fuel from the bore, first and second control chambers for receiving fuel under pressure and a control valve arrangement for controlling the fuel pressure within the first and second control chambers. The valve needle is moveable in response to a change in fuel pressure in at least one of the first and second control chambers.

Abstract: The present invention provides a fuel injector comprising a nozzle body within which first and second valve needles are slidable. The first valve needle is engagable with a first seating to control fuel injection from a first outlet opening provided in the nozzle body and the second valve needle is engagable with a second seating to control fuel injection from a second outlet opening provided in the nozzle body. The fuel injector further comprises first and second control chambers for fuel, whereby fuel pressure within the first and second control chambers controls movement of the first and second valve needles away from their respective seatings so as to permit fuel delivery from a selected outlet opening. The first and second valve needles being arranged adjacent to one another.

Abstract: A fuel injector comprising a valve needle which is slidable within a bore and engageable with a seating to control fuel delivery through first and second outlet openings. The valve needle is moveable between a closed position and first and second fuel injecting positions. The fuel injector further comprises a fuel supply passage for supplying fuel under pressure to the bore and a control chamber which is arranged to receive fuel from the fuel passage, in use. The valve needle is acted upon in use by a force due to fuel pressure within the control chamber. An actuator arrangement controls fuel pressure within the control chamber, and a damping means are provided for damping movement of the valve needle away from the seating into the first or second fuel injecting position. The supply passage for fuel may be provided with a restricted flow passage which serves to limit the amplitude of pressure waves within the supply passage.

Abstract: A piezoelectrically actuable fuel injector comprising an accumulator volume within which a piezoelectric stack is arranged, the accumulator volume being arranged to receive fuel from a source of pressurized fuel, in use. The piezoelectric stack carrying an end member which engages a surface associated with a piston member so as to apply a retracting force to the piston member upon a reduction in the axial length of the piezoelectric stack, the piston member being operable to control fuel pressure within a control chamber. A volume is defined between the end member and the surface associated with the piston member. The volume is provided with a vent arrangement to permit fuel within the volume to flow to a low pressure drain.

Abstract: A fuel injector comprising a nozzle body defining a bore within which an outer valve member is slidable, the outer valve member being engageable with a first seating to control fuel injection from a first outlet opening provided in a nozzle body. The outer valve member is provided with a through bore within which an inner valve member is slidable, the inner valve member being engageable with a second seating to control fuel injection through a second outlet opening provided in the nozzle body. The fuel injector further comprises first and second control chambers for fuel whereby, in use, movement of the inner and outer valve members away from their respective seatings is controlled by controlling fuel pressure within the first and second control chambers so as to permit fuel delivery from a selected outlet opening.

Abstract: A fuel injector comprising a nozzle body defining a first bore and an inwardly opening valve member slidable within the first bore, the valve member being engageable with a first seating to control fuel delivery through a first outlet opening provided in the nozzle body. The valve member is provided with a second bore within which an outwardly opening valve needle is slidable, the valve needle being engageable with a second seating to control fuel delivery through a second outlet opening provided in the valve needle. The fuel injector also comprises first and second control chambers for fuel, whereby fuel pressure within the first and second control chambers controls movement of the valve member and the valve needle away from their respective seatings so as to permit fuel delivery through a selected outlet opening.

Abstract: A fuel injector comprising a nozzle body having a first bore defining first and second seatings, an outer valve needle being slidable within the first bore and engageable with the first seating to control fuel flow from a first outlet opening. The outer valve needle is provided with a second bore within which an inner valve needle is slidable, the inner valve needle being engageable with the second seating to control fuel delivery through a second outlet opening. The outer valve needle includes a deformable region which is shaped such that, in use, when the outer valve needle is urged against the first seating, the outer valve needle deforms. The deformable region may be shaped such that, in use, when the outer valve needle is urged against the first seating, the outer valve needle deforms to close the first outlet opening.