A needle stroke switch and a fuel injector having such a switch, the needle stroke switch including a seat plate having a plate-like main body and a passage connecting the two planar sides of the plate-like main body, an anchor element which can be lifted off from the passage in the seat plate, and a control valve which is arranged on the side of the seat plate opposite the anchor element and is designed to interact with a nozzle needle. The seat plate is electrically isolated from a surrounding injector housing and an electrical connection to the injector housing is possible only via the nozzle needle which interacts with the seat plate. Furthermore, the needle stroke switch is characterised in that at least one ceramic and/or plastic part is provided which contacts the seat plate in order to isolate the seat plate from the surrounding injector housing.

A fuel injector feeds fuel to a combustion chamber of a cylinder of a dual-fuel engine and includes: a main body having a needle guide; a nozzle needle guidable in the needle guide; a needle fuel chamber defined by the main body, coupleable to the combustion chamber, wherein the orifices are open in a first position of the nozzle needle and closed in a second position of the nozzle needle; a first line arranged in the main body, and being coupled to the needle fuel chamber, via the first line a fuel being introduceable into the needle fuel chamber. In the main body a second line is coupleable to the needle guide and to a control chamber of a control valve of the fuel injector, wherein via the second line a fuel is feedable to the needle guide as barrier fluid and to the control chamber as working fluid.

A flow control system for a fuel injector of an internal combustion engine includes: an inlet channel, an outlet channel, a return channel for returning pressurized fuel to a low-pressure system having a lower pressure than the inlet channel, a fuel outlet chamber, a moveable nozzle control member in the fuel outlet chamber for selectively allowing the pressurized fuel to flow into the outlet channel, a biasing member biasing the nozzle control member towards a closed position, a moveable member defining, with the nozzle control member, a fuel control chamber configured to bias the nozzle control member towards its closed position, a moveable valve member for selectively opening and closing a flow passage and a fuel connection between the inlet channel and the fuel control chamber for pressurizing the fuel control chamber.

A fuel injection device injecting a fuel from an injection hole to a combustion chamber of an internal combustion engine includes a valve body including a fuel passage through which the fuel flows to the injection hole and a seat portion facing the fuel passage, a valve member moving in the valve body in an axial direction of the valve body and opening and closing the injection hole by being removed from and seated on the seat portion, a dividing member defining a pressure control chamber placed at a position opposite to the injection hole with respect to the valve member, and an outer peripheral member surrounding an exterior of an outer periphery of the dividing member. The pressure control chamber controls a movement of the valve member by a pressure of the fuel that is introduced. The outer peripheral member and the valve body constitute the fuel passage.

Operating an engine system and fuel system includes energizing a solenoid actuator for a spill valve in a fuel injector in a first engine cycle via a standard waveform to inject a shot of fuel. Operating an engine system and fuel system further includes determining suitability for reduced energy operating of the fuel system, and energizing the solenoid actuator via a reduced energy waveform based on the determining suitability so as to inject one or more shots of fuel in a second engine cycle. The operating methodology and control logic can extend an engine speed range for multi-shot fuel injection in an engine.

A method is provided for determining the fuel temperature in the high-pressure zone of a fuel injection system of a motor vehicle. The fuel injection system has at least one injector operated by a servo valve which is actuated by means of a piezo actuator. After an injection process has been carried out, the piezo actuator is discharged after the injection has ended in such a way that the servo valve can close, but a non-positive connection remains between the piezo actuator and the servo valve. This condition of reduced charge is maintained. The pressure oscillation of the actuator voltage resulting from this is recorded and from this the hydraulic natural frequency of the enclosed high-pressure volume of fuel is deduced. The prevailing fuel temperature can be determined from the natural frequency.

A fuel system includes a fuel injector having a split check assembly with a control piece, an outlet piece, and a check sleeve. A trapped volume is formed between the control piece and the outlet piece within the check sleeve, to hydraulically couple the control piece to the outlet piece. A starting rate shape clearance fluidly connects the trapped volume to a fuel cavity and is formed between the check sleeve and one of the control piece or outlet piece received therein, and modulates a starting rate shape of fuel injection from the fuel injector. Related methodology is disclosed.

A fuel injector nozzle assembly includes a two-piece outlet check having a timing control piece and a rate control piece. A nozzle passage is formed between a nozzle body and a two-piece outlet check, and a sac cavity is formed by the rate control piece and the nozzle body and fluidly connects a through-hole in the rate control piece to nozzle outlets. A starting-flow clearance is formed by the rate control piece and the timing control piece, and is opened by moving the timing control piece relative to the rate control piece. Moving the rate control piece relative to the nozzle body opens a main-flow seat. The nozzle assembly provides a slow starting injection rate shape in a common rail or similar fuel system and improved controllability over minimum delivery quantities.

A fuel injector includes a collar, which may be formed of a porous, sintered material, the collar being located around the needle and allowing a restricted fluid pathway, such as orifices through the collar, between first and second volumes of fuel, the collar being located in a section of the nozzle body which has a greater cross-sectional area than the rest of the bore.

A subassembly for a high pressure fuel injector control valve includes, a control valve member and a sleeve attached to a stem of the control valve member, the sleeve extending along at least a partial axial length of the stem of the control valve member, and wherein a clearance, provided between the sleeve and the control valve member, is in fluid communication with the control chamber such that during use, pressure compensation occurs, as the sleeve is caused to expand and seal against the control valve bore, thereby preventing leakage of fuel within the control valve assembly.