Fuel injection control device and fuel injection system

A fuel injection system comprising:

• an injector to inject a fuel into an internal combustion engine;
• a delivery pipe to distribute and supply the fuel to the injector of each cylinder of the internal combustion engine;
• a high-pressure pump to pump a high-pressure fuel that is the fuel a pressure of which is increased into the delivery pipe;
• a fuel pressure sensor attached to the delivery pipe and to sense a fuel pressure of the fuel in the delivery pipe;
• and
• a fuel injection control device to include an electric controller to control an opening and closing of the injector by energizing a coil in the injector, and a booster circuit to boost a battery voltage that is a voltage supplied from a battery to generate a boost voltage, wherein
• the electric controller includes
• a valve-opening control unit to apply the boost voltage to the coil and then to apply the battery voltage to the coil to execute a valve-opening control to generate a required valve-opening force that is an attractive force required to start to open the injector,
• an open valve maintenance control unit to apply the battery voltage to the coil to execute an open valve maintenance control to generate an open valve maintenance force that is an attractive force holding the opening of the injector and is smaller the required valve-opening force, after the valve-opening control, and
• a current correction control unit to execute a current correction control to correct a maximum value of a current flowing through the coil when the boost voltage is applied to the coil in the valve-opening control, according to a decreasing quantity of the battery voltage,
• the current correction control unit sets a correction quantity in the current correction control according to the decreasing quantity of the battery voltage and a pressure of the fuel supplied to the injector, and
• the current correction control unit suppresses a correction that increases excessively in the current correction control when the required valve-opening force becomes lower while a fuel pressure that is a pressure of the fuel becomes lower in a case where the battery voltage decreases.