Various methods and systems are provided for a fuel injector. In one example, a fuel injector includes a nozzle tip including a plurality of injection holes, a first needle biased against the nozzle tip via a first biasing member positioned within a first control volume, and a second needle surrounding a portion of the first needle and biased against the first needle and the nozzle tip via a second biasing member positioned within a second control volume. A needle actuator may be energized for different durations of time in order to move one or more of the first needle and the second needle relative to the nozzle tip.

A metering system for a fluid atomizer includes a housing, first and second metering members, and at least one solenoid. The housing includes a mixing chamber. The first metering member is operable to control flow of a first fluid to the mixing chamber. The second metering member is arranged coaxial with the first metering member and operable to control flow of a second fluid to the mixing chamber. The at least one solenoid is configured to operate at least one of the first and second metering members.

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.

A fuel injector is disclosed. The fuel injector may have an injector body having a fuel inlet and at least one orifice. The fuel injector may also have a first check valve member. The first check valve member may be selectively movable to fluidly block a first flow of fuel from the fuel inlet to the at least one orifice. The fuel injector may have a second check valve member. The second check valve member may be selectively movable to fluidly block a second flow of fuel from the fuel inlet to the at least one orifice. The fuel injector may also have a control valve assembly. The control valve assembly may be configured to selectively operate either the first check valve or both the first check valve and the second check valve to fluidly connect the fuel inlet and the at least one orifice.

An injector is provided, comprising an injector body comprising an inlet passage configured to receive fluid, at least one injection outlet configured to deliver fluid, and a central bore, a needle valve disposed for reciprocal movement within the central bore between a closed position and an opened position; and an actuator configured to move the needle valve between the closed position wherein a first portion of a surface of the valve tip engages a first portion of a surface of the injector body to form a first seal that inhibits flow through the at least one injection outlet, and the opened position wherein a second portion of the surface of the valve tip engages a second portion of the surface of the injector body to form a second seal that inhibits flow through the drain outlet.

A fuel injector has means to directly inject one type of fuel or two types of fuels collectively with fuel ratios on demand. Once being used as a single fuel injector, the injector can enable injection rate shaping. Once being used as a dual fuel injector, the injector can tailor fuel properties on demand. The fuel injector has the capability to enable tailored chemical and thermal-physical fuel properties to enable high efficiency clean combustion for different engine loads and speeds.

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.

A fuel injection device is provided with a valve body, a nozzle needle, a movable plate, and a support spring. The valve body has a control chamber therein. The control chamber is defined by a defining wall which has a dividing wall portion. The dividing wall portion divides the control chamber into an accommodation chamber and a backpressure chamber. The accommodation chamber accommodates a movable plate and a support spring. A fuel pressure in the backpressure chamber is applied to the nozzle needle. The dividing wall portion has a restriction hole fluidly connecting the accommodation chamber and the backpressure chamber with each other, and a support surface supporting the support spring.

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.