Hydraulically actuated gaseous fuel injectors required a relatively small pressure bias between hydraulic fluid and gaseous fuel to be able to open and to reduce hydraulic fluid contamination of the gaseous fuel. An improved hydraulically actuated gaseous fuel injector includes an injection valve in fluid communication with a gaseous fuel inlet and includes a valve member reciprocatable within a fuel injector body between a closed position and an open position. There is a lift chamber in fluid communication with a hydraulic fluid inlet such that hydraulic fluid pressure in the lift chamber contributes to an opening force applied to the valve member. A control chamber is in fluid communication with the hydraulic fluid inlet such that hydraulic fluid pressure in the control chamber contributes to a closing force applied to the valve member. A control valve is operable to reduce hydraulic fluid pressure in the control chamber such that the opening force is greater than the closing force and the valve member moves to the open position.

A fuel injector assembly in one embodiment includes a nozzle, at least one needle, and at least one actuator. The nozzle includes at least one cavity in fluid communication with nozzle openings. The at least one needle is movably disposed within the at least one cavity, and prevents flow through the nozzle openings in a closed position. The at least one actuator is configured to move the at least one needle within the cavity. The at least one actuator is configured to move the at least one needle to at least a first fuel delivery configuration and a second fuel delivery configuration. A first amount of fuel is delivered through the nozzle openings with the at least one needle in the first fuel delivery configuration, and a second amount of fuel is delivered through the nozzle openings with the at least one needle in the second fuel delivery configuration.

Operating an engine includes injecting a first charge of liquid fuel using a first set of nozzle outlets in a fuel injector, and injecting a second charge of liquid fuel using a second set of nozzle outlets in a fuel injector. The first charge is autoignited in a first engine cycle, and the second charge is autoignited in a second engine cycle, and may be used to pilot ignite a charge of gaseous fuel. Operating the engine further includes limiting errors in targeting of the second charge of liquid fuel caused by transitioning the engine from a first combination to a second combination of speed, load, and boost, by varying an injection pressure of the liquid fuel from the first engine cycle to the second engine cycle.

Methods and systems are provided for a multi-hole nozzle of a fuel injector. In one example, a nozzle for a fuel injector may include multiple nozzle holes arranged at a nozzle tip, where each nozzle hole has a straight flow axis and a cross-section that twists around the straight flow axis, from an inlet to an outlet of the nozzle hole. Additionally, a long side of the cross-section may increase in length, along the nozzle hole, from the inlet to the outlet.

Operating an engine includes injecting a first charge of liquid fuel using a first set of nozzle outlets in a fuel injector, and injecting a second charge of liquid fuel using a second set of nozzle outlets in a fuel injector. The first charge is autoignited in a first engine cycle, and the second charge is autoignited in a second engine cycle, and may be used to pilot ignite a charge of gaseous fuel. Operating the engine further includes limiting errors in targeting of the second charge of liquid fuel caused by transitioning the engine from a first combination to a second combination of speed, load, and boost, by varying an injection pressure of the liquid fuel from the first engine cycle to the second engine cycle.

A fuel system for an internal combustion engine includes a fuel injector having a nozzle with first and second sets of spray orifices formed therein. The fuel injector also includes a first and a second outlet check movable to open and close the first and second sets of spray orifices. Spray plume ducts are supported at fixed orientations relative to a nozzle of the fuel injector, and each are oriented in-line with a center axis defined by one of the spray orifices. The spray plume ducts may be directly attached to the fuel injector or to a duct carrier mounted to an engine head.

A fuel system for an internal combustion engine includes a fuel injector having a nozzle with first and second sets of spray orifices formed therein. The fuel injector also includes a first and a second outlet check movable to open and close the first and second sets of spray orifices. Spray plume ducts are supported at fixed orientations relative to a nozzle of the fuel injector, and each are oriented in-line with a center axis defined by one of the spray orifices. The spray plume ducts may be directly attached to the fuel injector or to a duct carrier mounted to an engine head.

A multi-fuel injector assembly in one embodiment includes a first fuel injector assembly to deliver a first type of fuel and a second fuel delivery system to deliver a second type of fuel. The first fuel injector includes a first nozzle, at least one first needle, and at least one first actuator configured to move the at least one first needle. The at least one first actuator moves the at least one first needle to a first fuel delivery configuration that corresponds to a first fuel mixture composition, and a second fuel delivery configuration that corresponds to a second fuel mixture composition.

A liquid fuel injector for a fuel system in an internal combustion engine includes two injection control valves for controlling two outlet checks. A common nozzle supply cavity is fluidly connected to an inlet passage and supplies each of the two sets of nozzle outlets opened and closed by the outlet checks. A first nozzle outlet set forms a narrower spray angle and has a first combination of outlet number and outlet size, and a second nozzle outlet set forms a wider spray angle and has a second combination of outlet number and outlet size. The first nozzle outlet set has a greater steady flow than the second nozzle outlet set.

The invention relates to a fuel injector for injecting two liquid and/or gaseous fuels with an injector housing (1), comprising a nozzle body (2) and a valve body (3). A first nozzle needle (7), arranged such that it can move in a stroke-like manner, is arranged in said injector housing (1) for opening and closing an injection cross-section (27). The first nozzle needle (7) is thereby designed as a hollow needle in which a second nozzle needle (8), arranged such that it can move in a stroke-like manner, is arranged. Same cooperates with an inner nozzle seat (25) formed in the first nozzle needle (7) to open and close at least one injection opening (35). The first nozzle needle (7) and the second nozzle needle (8) border an injection chamber (20) that can be filled with fuel via a supply throttle (36). In addition, in an upper switch position, the second nozzle needle (8) is in contact with a seal seat (38) and thereby separates a connection between the injection chamber (20) and the supply throttle (36).