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 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.

Fuel injection valve having a magnet armature (18) which interacts with a valve seat (19), which is formed on a valve piece (15), in order to open and close an outflow opening (20), wherein the magnet armature (18) can be moved away from the valve seat (19) by an electromagnet (24). A valve piece (15) delimits a control chamber (12), wherein the outflow opening (20) opens into the control chamber (12), and the control chamber (12) can be charged with fuel at high pressure that exerts a hydraulic force on the valve piece (15). Between the magnet armature (18) and the valve piece (15), there is arranged a bracing element (30) which is preloaded against the valve piece (15) and which exerts a force on the valve piece (15) in the region of the outflow opening (20) in the direction of the control chamber (12).

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.

An injection hole body has injection holes to inject fuel. A valve body forms a fuel passage with an inner surface of the injection hole body to communicate with inflow ports of the injection holes. The valve body opens and closes the fuel passage by being seated on and unseated from a seating surface of the injection hole body. An inflow port gap distance is a gap between the valve body and the inflow ports along a center axis of the valve body. An inter-injection hole distance is a distance between inflow ports, which are adjacent to each other, among the inflow ports placed around the center axis. The inter-injection hole distance is smaller than the inflow port gap distance in a state where the valve body is unseated from the seating surface and is at a farthest position in its movable range.

An injection hole body has an injection hole to inject fuel for causing combustion in an internal combustion engine. 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 fuel passage therebetween to communicate with an inflow port of the injection hole. The fuel passage is opened and closed by unseating and seating of the valve body. A resilient member generates a resilient force to urge the valve body toward the seating surface. A seat angle is an angle between two straight lines appearing in a cross section of the seating surface, the cross section including a center axis of the valve body. The seat angle is 90 degrees or less.

A fuel system includes a fuel injector having a fuel passage and a purging fluid passage formed therein. A nozzle tip inner surface defines a sac forming a blind end of the fuel passage in the fuel injector. A coaxial concentric check assembly includes a purging check movable to admit a purging fluid such as pressurized air into the fuel passage to purge the sac of fuel. Reduced injector dribble is observed from the purging of fuel.

The present application concerns a fuel-injection metering device for a motor vehicle. The fuel-injection device include a main body with at least one through-hole, whereby the main body forms a valve seat on its inner face that is provided to interact with a valve body, whereby the inner face of the main body is electrochemically machined. The application also concerns a mould, a production method, and a fuel-injection nozzle.

A throttle portion is defined between an upper end of a sac chamber and a conical portion of a needle to have a throttle opening area S1. Half of an area surrounded by the throttle portion, the needle, an inner wall of the sac chamber, and a lower end extended line in a cross section of the sac chamber taken along a sac center line is an injection hole upstream area S2. A lift amount, when the throttle opening area S1 is equal to an area which is calculated by multiplying an injection hole area S3 by the number of the injection holes, is a predetermined lift amount L. A viscosity coefficient of fuel is . An index value Sa, which is calculated in accordance with an equation as below, is set to 0.5 or greater. $S_a=\frac{}{2}{}_{h=0}^{h=L}{\left(\frac{S_1}{S_2-S_1}\right)}^2\mathrm{dh}$

The invention relates to an injection nozzle (1) for injecting a fluid, in particular a liquid or gaseous fuel, comprising: a nozzle body (2) which is designed to be hollow-cylindrical at least in portions and forms a sealing seat (3) via which a flow path (4) for the fluid to be injected leads, a nozzle needle (5) which is accommodated in the nozzle body (2) for reciprocating movement and has a sealing surface (6) that interacts with the sealing seat (3), a guide element (7) which is fixedly connected to the nozzle needle (5) and is guided by means of an external guide (8) of the nozzle body (2).

The invention further relates to a fuel injector having an injection nozzle (1) according to the invention.