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 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 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.

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.