Fuel injection control apparatus for internal combustion engine and method for operating fuel injection control apparatus for internal combustion engine

A method for operating a fuel injection control apparatus for an internal combustion engine, wherein the fuel injection control apparatus includes a low pressure fuel pump configured to pump fuel from a fuel tank, a low pressure fuel passage through which the fuel discharged from the low pressure fuel pump flows, a high pressure fuel pump configured to pressurize the fuel supplied from the low pressure fuel passage, a high pressure fuel passage through which the fuel pressurized by the high pressure fuel pump flows, and a fuel injection valve configured to inject the fuel of the high pressure fuel passage, the method comprising:

• controlling driving of the high pressure fuel pump so that fuel pressure of the high pressure fuel passage approaches a high pressure target value, which is a target value of the fuel pressure;
• controlling driving of the low pressure fuel pump;
• calculating a feedforward correction amount so that when the high pressure target value increases, the feedforward correction amount increases as a request injection amount of the fuel injection valve increases and also increases as an increase rate of the high pressure target value increases;
• calculating a feedback correction amount based on a low-side pressure deviation when the high pressure target value increases, wherein the low-side pressure deviation is a difference obtained by subtracting fuel pressure of the low pressure fuel passage from a low pressure target value, which is a target value of fuel pressure of the low pressure fuel passage;
• and
• controlling driving of the low pressure fuel pump based on a sum of the feedforward correction amount and the feedback correction amount.

A fuel injection control apparatus for an internal combustion engine comprising:

• a low pressure fuel pump configured to pump fuel from a fuel tank;
• a low pressure fuel passage through which the fuel discharged from the low pressure fuel pump flows;
• a high pressure fuel pump configured to pressurize the fuel supplied from the low pressure fuel passage;
• a high pressure fuel passage through which the fuel pressurized by the high pressure fuel pump flows;
• a fuel injection valve configured to inject the fuel of the high pressure fuel passage;
• and
• circuitry, wherein the circuitry is configured to perform:
• controlling driving of the high pressure fuel pump so that fuel pressure of the high pressure fuel passage approaches a high pressure target value, which is a target value of the fuel pressure;
• controlling driving of the low pressure fuel pump;
• calculating a feedforward correction amount so that when the high pressure target value increases, the feedforward correction amount increases as a request injection amount of the fuel injection valve increases and also increases as an increase rate of the high pressure target value increases;
• calculating a feedback correction amount based on a low-side pressure deviation when the high pressure target value increases, wherein the low-side pressure deviation is a difference obtained by subtracting fuel pressure of the low pressure fuel passage from a low pressure target value, which is a target value of fuel pressure of the low pressure fuel passage;
• and
• controlling driving of the low pressure fuel pump based on a sum of the feedforward correction amount and the feedback correction amount.