A valve for metering fluid under pressure includes: a valve housing having an inlet opening and a metering opening for the fluid; an outward-opening valve needle pressure equalized via an elastic hollow body which is subject to the fluid pressure; and an electromagnet which lifts the valve needle up from the metering opening against the force of a valve closing spring. The valve housing is assembled from a valve tube and one valve body on the metering end and another on the inlet end, each being connected in a fluid-tight manner to the valve tube at the tube ends. The magnet pot including the enclosed solenoid coil is secured on the valve tube on the outside by the electromagnet, and the magnetic core is secured on the valve tube on the inside in such a way that it surrounds a needle section of the valve needle.

The invention relates to a nozzle assembly for a fuel injector, comprising a nozzle needle (1), which is accommodated in a high-pressure bore (2) of a nozzle body (3) in such a way that the nozzle needle can be moved in a reciprocating manner in order to open and close at least one injection opening (4) and to which a spring force of a spring (5) is applied at least indirectly in a closing direction, wherein the nozzle needle (1) is surrounded by a throttle bore body (7) at least in some regions in order to form at least one closing throttle (6). According to the invention, the throttle bore body (7) has a multi-part design and comprises at least two sleeves (7.1, 7.2), which are guided in each other at least in some regions. The invention further relates to a fuel injector comprising such a nozzle assembly.

A fuel injection valve includes a fixed core formed into a cylindrical shape, a valve plunger that can move closer to or away from the fixed core, a retainer formed with a substantially C-shaped cross-section having one long straight opening extending linearly along the entire length in an axial direction while having a tapered face on an outer periphery of each of opposite end parts in the axial direction and is press fitted into the fixed core, and a return spring provided between the retainer and the valve plunger. A cutout is provided in peripherally opposite end parts of the retainer for increasing the width between opposite end parts in a longitudinal direction of the opening. This enables the degree of freedom in selecting the material for forming a retainer while preventing the occurrence of galling or generation of swarf when press fitting the retainer into the fixed core.

A hydraulic coupling is specified, particularly for fuel injectors, which has a housing pot having a pot bottom and a lateral pot surface, a piston guided axially displaceably in the housing pot, a fluid-filled coupling gap that is provided between the piston and the pot bottom, diaphragm situated on the outer side of the housing pot facing away from the piston, a compensation chamber that is bordered by the diaphragm and flow-connected to the coupling gap, and a spring element acting upon the diaphragm with an axially directed spring force. In order to achieve a low overall stiffness of the hydraulic coupling at the required specified coupling force, the spring element is developed as a spring bracket fixed to the housing pot, which lies against the diaphragm with axial prestressing in the region of the pot bottom.

A fuel injector for use in an internal combustion engine includes a valve member that is moveable within a bore of an injection nozzle so as to be engageable with a valve seat region to control fuel delivery through one or more nozzle outlets, an injector body housing an actuator that is operable to move the valve member within the bore, and defining an accumulator volume for storing high pressure fuel. The fuel injector includes a damping chamber in fluid communication with the accumulator volume through a fluid passage, the damping chamber serving to reduce pressure wave activity within the accumulator volume.

A nozzle assembly of a fuel injector extends along a main axis and includes a nozzle body provided with an inner space divided in upstream chamber and downstream chamber and also with, a valve needle including a main elongated shaft slidably guided in said inner space and extending through-out both upstream and downstream chambers. The nozzle body and the valve needle cooperate to define throttle fluid communication means between upstream and downstream chambers inducing, in use, a pressure drop when fuel flows through. The nozzle assembly is further provided with a tubular sleeve arranged between the upstream chamber and the downstream chamber in abutment against a face of the body and being radially self-centred guided by a cylindrical face of the needle, the throttle means being arranged in said sleeve.