A nozzle assembly of a fuel injector includes a nozzle body in which a needle member is adapted to translate. The nozzle assembly is further provided with an electrical circuit so that an electrical signal enabling contact detection is measurable between the needle member and the nozzle body. The nozzle assembly also includes a piezoresistive device which continuously varies the electrical signal during the final closing displacements, or the initial opening displacements, of the needle, the variations of the signal being a function of a differential pressure.

A fuel injector for an internal combustion engine. The fuel injector has a needle and a nozzle that inter-relate with each other in assembly. Relative movement between the needle and nozzle bring the fuel injector between a closed state of operation and an open state of operation amid use of the fuel injector. The nozzle has one or more passages therein through which fuel is discharged. Fuel flow is precluded at a sac volume of the fuel injector.

A valve is provided, in particular an injection valve, having a valve seat and a valve needle which extends along a closing direction for the most part, the valve seat having a valve-seat surface, and a valve-closing element is mounted on an end of the valve needle facing the valve seat, the valve-closing element being able to be moved between an open position and a closed position, and the valve-closing element together with the valve-seat surface forming a sealing seat in the closed position, the valve-closing element having a greater core hardness and/or surface hardness than the valve-seat surface.

An injector tip for a fuel injector includes an exterior surface, and an interior surface defining a sac region therein. The injector tip is also configured to define at least one orifice radially extending from the interior surface to the exterior surface. The orifice is disposed in communication with the sac region located adjacent to the interior surface. Further, the injector tip also includes a mound that is defined on the interior surface such that the mound is integrally formed with the interior surface adjacent to the sac region. The mound is configured to extend along an axis of the sac region and terminate prior to a perimeter of the at least one orifice.

Methods and systems are provided for a fuel injector. In one example, a system may include forming an annular venturi passage between an outlet surface of the fuel injector and a nozzle. The nozzle may further comprise one or more air entraining features that may work in concert with the annular venturi passage to promote air-fuel mixing.

A nozzle assembly of a fuel injector includes a nozzle body in which a needle member is adapted to translate. The nozzle assembly is further provided with an electrical circuit so that an electrical signal enabling contact detection is measurable between the needle member and the nozzle body. The nozzle assembly also includes a piezoresistive device which continuously varies the electrical signal during the final closing displacements, or the initial opening displacements, of the needle, the variations of the signal being a function of a differential pressure.

Methods and systems are provided for a fuel injector. In one example, a system may include forming an annular venturi passage between an outlet surface of the fuel injector and a nozzle. The nozzle may further comprise one or more air entraining features that may work in concert with the annular venturi passage to promote air-fuel mixing.

Methods and systems are provided for a fuel injector. In one example, a system may include a fuel injector having a half-annular venturi shaped outlet passage arranged between an outlet surface of the fuel injector and a half-cone shaped end portion of a nozzle. The nozzle may further comprise one or more air entraining features working in tandem with the half-annular venturi outlet passage to promote air-fuel mixing.

A valve is provided, in particular an injection valve, having a valve seat and a valve needle which extends along a closing direction for the most part, the valve seat having a valve-seat surface, and a valve-closing element is mounted on an end of the valve needle facing the valve seat, the valve-closing element being able to be moved between an open position and a closed position, and the valve-closing element together with the valve-seat surface forming a sealing seat in the closed position, the valve-closing element having a greater core hardness and/or surface hardness than the valve-seat surface.

An injection hole body has multiple injection holes for injecting fuel. A valve body is unseated from and seated on a seating surface of the injection hole body. The injection hole body and the valve body form a specific space therebetween to communicate with inflow ports of the injection holes. A virtual region is surrounded by multiple straight lines. The straight lines connect portions of peripheral edges of the inflow ports, which are closest to a center axis of the valve body in the radial direction. A center volume is formed by extending the virtual region from the injection hole body toward the valve body along the center axis. A total injection hole volume is a total volume of the injection holes. The total injection hole volume is larger than the center volume in a state where the valve body is seated on the seating surface.