Pressure accumulation fuel injection controller

A pressure accumulation fuel injection controller having a pressure accumulation vessel for accumulating high-pressure fuel, a fuel injection valve for injecting the high-pressure fuel accumulated in the pressure accumulation vessel into respective cylinders of an engine, and a fuel supply pump for pressurizing suctioned fuel and for pressure-feeding the fuel to the pressure accumulation vessel, wherein the fuel injection controller regulates the fuel discharge from the fuel supply pump into the pressure accumulation vessel to conform a common rail pressure in the pressure accumulation vessel to a target common rail pressure and injects the fuel from the injection valves into the cylinders, the fuel injection controller comprising:

• a pressure pattern estimation device that is configured with an injection period based on a required injection amount and the target common rail pressure and that estimates a pressure transition of the fuel in the pressure accumulation vessel during the injection period;
• a surplus pressure range calculation device that is configured with the target common rail pressure based on pressure pattern data provided by the pressure pattern estimation device and that calculates a surplus pressure range in which the pressure pattern data during the injection period exceeds the target common rail pressure;
• and
• a pressure reduction valve that performs control for discharging the common rail pressure to a lower-pressure side to eliminate the surplus pressure range calculated by the surplus pressure range calculation device.