FUEL INJECTION APPARATUS

PROBLEM TO BE SOLVED: To provide a fuel injection apparatus having an injector with a solenoid device as an actuator, in which injection characteristics can be stably changed. SOLUTION: The solenoid device of the injector has an irregular pitch coil spring as an energizing means 28 that energizes a control valve body for opening and closing a control chamber toward an opposite side of a lift direction. The energizing means 28 has spring characteristics such that, if an amount of deflection thereof due to compressive load is increased more than a boundary value, a spring coefficient thereof is also increased. Further, an ECU varies the maximum amount of current at an initial current feed according to the load of an engine. With this configuration, if the control valve body moves to pass through from a balanced position toward one side owing to its inertia, force of the spring abruptly grows strong. This prevents the control valve body from passing through too far and also attenuates vibration quickly. As a result, the fuel injection system can stably change injection characteristics. COPYRIGHT: (C)2010,JPO&INPIT