Fuel injection control device

A fuel injection control device comprising:

• bodies having nozzle holes for injecting fuel into combustion chambers in an engine;
• needle valves reciprocating in hollow portions in the bodies to open and close the nozzle holes;
• balance chambers supplied a part of injection fuel to control the lift of the needle valves, an end of the needle valves forming fuel pressure receiving surfaces in the balance chambers;
• supply passages to supply a fuel pressure to the balance chambers;
• discharge passages to release the fuel pressure in the balance chambers;
• open-close valves to open and close the discharge passages;
• solenoid actuators to drive the open-close valves;
• sensors to detect the operating condition of the engine;
• and
• a controller to control drive current supply to the solenoid actuators according to the operating condition detected by the sensors;
• wherein the controller sets a pull-in current conduction period of the drive current supplied to the solenoid actuators when the operating condition detected by the sensors is a low load operation, to a value shorter than a pull-in current conduction period of the drive current supplied to the solenoid actuators when the operating condition detected by the sensors is a high load operation.