A gas injector for the direct injection of gaseous fuel into a combustion chamber of an internal combustion engine, including a valve seat, a valve needle, which in response to a lift releases a first cross-sectional area at the valve seat, and a gas control region, which is situated at the valve needle and defines a second cross-sectional area together with a component surrounding the valve needle, and in response to a lift, a change in the first cross-sectional area at the valve seat differs from a change in the second cross-sectional area at the gas control region.

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.

The present disclosure relates to a fuel injector for injecting fuel into a combustion engine. It may comprise a valve with a movable needle, two springs pushing the needle toward the closed position, and an actuator for opening the valve. The needle may be in a fuel reservoir of a valve body. The actuator may supply pressurized fuel to the fuel reservoir so that the fuel pressure forces the needle away from the closed position against the spring force of the first spring or the first and second springs, respectively. There may be play between the second spring and the needle when the needle is in the closed position.

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 fuel nozzle for a combustor includes a fuel body, a primary fuel passage having a primary fuel outlet, and a secondary fuel passage having a secondary fuel outlet, the secondary fuel passage being non-concentric with the primary fuel passage. The primary fuel outlet and the secondary fuel outlet are non-parallel. An axial centerline of the primary fuel outlet is angled with respect to an axial centerline of the primary fuel passage and an axial centerline of the secondary fuel outlet is colinear with an axial centerline of the secondary fuel passage. Also provided is a method of introducing non-concentric, non-parallel fuel flows to a combustor is also provided.

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.