The fuel injection valve includes a valve body having an injection hole at an end of the valve body facing in a first direction, and a needle valve provided inside the valve body and movable in an axial direction which includes the first direction and a second direction opposite to the first direction. A first control valve and a second control valve control the internal pressure of a back pressure chamber provided inside the valve body, a first actuator controls the first control valve, and a second actuator controls the second control valve. The second control valve is longer than the first control valve in the axial direction. The second actuator is located away in the second direction from the first actuator. A part of the second actuator overlaps at least a part of the first actuator when viewed in a plan view along the axial direction.

A fuel injector for an internal combustion engine is disclosed. The fuel injector is particularly suitable for use as a dual fuel injector, and comprises a generally tubular outer valve needle, an inner valve needle slidably received in the outer valve needle, and a nozzle body assembly comprising a tip part and a needle guide part. The tip part defines a seating region for the outer valve needle, and the needle guide part comprises a guide bore for slidably receiving the outer valve needle. In one embodiment, a lower bore region of the needle guide part defines a cavity around the outer valve needle which houses a biasing spring for the outer valve needle and a fuel. A collar for seating the biasing spring can be dimensioned to allow free flow of the fuel from the cavity into an annular accumulator volume defined between the outer valve needle and the bore of the tip part.

The present disclosure provides a method for operating an injector of an internal combustion engine, the nozzle needle of said injector being operated by a piezo actuator by means of a servo valve. The method may include eliminating the idle travel of the piezo actuator by maintaining a permanent direct force connection between the piezo actuator and the servo valve, so that a change in force on the servo valve due to a change in pressure in the valve chamber when the servo valve is opened and closed and when the nozzle needle of the injector is closed is always transmitted to the piezo actuator as a change in force, detecting the resulting change in voltage and/or capacitance of the piezo actuator, and ascertaining parameters with which the injection quantity which is output by the injector is regulated based on the result of the detection.

A fuel injector for an internal combustion engine is disclosed. The fuel injector is particularly suitable for use as a dual fuel injector, and comprises a generally tubular outer valve needle, an inner valve needle slidably received in the outer valve needle, and a nozzle body assembly comprising a tip part and a needle guide part. The tip part defines a seating region for the outer valve needle, and the needle guide part comprises a guide bore for slidably receiving the outer valve needle. In one embodiment, a lower bore region of the needle guide part defines a. cavity around the outer valve needle which houses a biasing spring for the outer valve needle and a fuel. A collar for seating the biasing spring can be dimensioned to allow free flow of the fuel from the cavity into an annular accumulator volume defined between the outer valve needle and the bore of the tip part.

A fuel injector (100) for an internal combustion engine is disclosed. The fuel injector is particularly suitable for use as a dual fuel injector, and comprises a generally tubular outer valve needle (130), an inner valve needle (140) slidably received in the outer valve needle (130), and a nozzle body assembly (112) comprising a tip part (120) and a needle guide part (118). The tip part (120) defines a seating region (120f) for the outer valve needle (130), and the needle guide part (118) comprises a guide bore (118e) for slidably receiving the outer valve needle (130). In one embodiment, the tip part (120) and the needle guide part (118) are made from different materials, and a biasing spring (148) for the outer valve needle (130) is housed in the nozzle body assembly (112).

A fuel injector for delivering gaseous fuel to an internal combustion engine comprises: a nozzle body having a nozzle bore; a first valve needle received within the nozzle bore and engageable with a first valve seat to control gaseous fuel delivery through at least one outlet of an injection nozzle; a first actuator arrangement for controlling movement of the first valve needle;

a second valve needle engageable with a second valve seat to control gaseous fuel delivery through at least one outlet of the injection nozzle; and a second actuator for controlling movement of the second valve needle. The second valve seat is defined by the first valve needle, which defines an internal flow path for gaseous fuel flow when the second valve needle is lifted from the second valve seat and the first valve needle is lifted from the first valve seat.