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.

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 injection control device includes an electric controller controlling an opening and closing of an injector by energizing a coil in the injector, and a booster circuit boosting a battery voltage to generate a boost voltage. The electric controller includes a valve-opening control unit applying the boost voltage and then applying the battery voltage to the coil to execute a valve-opening control to generate a required valve-opening force, an open valve maintenance control unit applying the battery voltage to the coil to execute an open valve maintenance control to generate an open valve maintenance force and is smaller the required valve-opening force, after the valve-opening control, and a current correction control unit executing a current correction control to correct a maximum value of a current flowing through the coil when the boost voltage is applied in the valve-opening control, according to a decreasing quantity of the battery voltage.

A system includes an injector including a scheduling valve assembly and a nozzle in fluid communication with the valve assembly. The scheduling valve assembly is configured for regulation of flow from an inlet of the injector to the nozzle. The injector includes one fluid circuit between the inlet of the injector and a respective outlet of the nozzle. A solenoid valve is connected in fluid communication with the scheduling valve assembly. The solenoid valve is configured to adjust position of a hydromechanical valve spool of the valve assembly.

A system includes an injector having a scheduling valve assembly and a nozzle in fluid communication with the valve assembly. The scheduling valve assembly is configured for regulation of flow from an inlet of the injector to the nozzle. The injector includes two fluid circuits between the inlet of the injector and two respective outlets of the nozzle for staged flow output from the nozzle. A first one of the two fluid circuits is a primary circuit, and a second one of the two fluid circuits is a secondary circuit. A solenoid valve is connected in fluid communication with the scheduling valve assembly, wherein the solenoid valve is configured to adjust position of a hydromechanical valve spool of the valve assembly.

A first spring axially urges a needle valve toward an injection hole. A second spring axially urges a movable core toward a stationary core with an urging force that is smaller than an urging force of the first spring. A stopper is placed on one axial side of the movable core where the injection hole is located. The stopper limits movement of the movable core toward the injection hole to limit an amount of compression of the second spring.

A fuel injection device includes a nozzle holder; a fixed core; an anchor; and a valve member. The valve member has a plunger rod and a spacer. The plunger rod is provided with a shaft portion, and an engaging portion that engages with the anchor during a valve opening operation. The spacer has an accommodating portion in which the engaging portion is accommodated and forms a predetermined gap between the engaging portion and the anchor when the valve is closed. Further, the accommodating portion and the engaging portion are in line contact or point contact.

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.

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 injection device includes a nozzle holder; a fixed core; an anchor; and a valve member. The valve member has a plunger rod and a spacer. The plunger rod is provided with a shaft portion, and an engaging portion that engages with the anchor during a valve opening operation. The spacer has an accommodating portion in which the engaging portion is accommodated and forms a predetermined gap between the engaging portion and the anchor when the valve is closed. Further, the accommodating portion and the engaging portion are in line contact or point contact.