•  The solenoid valve coil controls inflow/outflow of fuel to the control chamber by opening and closing according to an ON/OFF signal received from the PCM.

―  When the solenoid valve coil is not energized, the plate is pushed down, closing the control chamber outflow orifice to valve ball, and causing the pressurized fuel from the fuel injection pipe to fill the control chamber. Due to this, the nozzle connected to the valve control plunger is closed and injection does not occur.

―  When solenoid valve coil energization begins the valve ball and plate are pulled upwards, opening the control chamber outflow orifice and fuel outflow occurs. As fuel outflow occurs, the control chamber pressure decreases, drawing the valve control plunger and the nozzle upward, and injection begins. As energization continues the nozzle is opened even more, providing maximum injection rate. When energization of the solenoid valve coil ends, the plate once again moves down and the nozzle is closed instantaneously. Since the coil can be repeatedly energized any number of times, multiple pilot injection is made possible.