Fuel supply device for internal combustion engine

A fuel supply device for an internal combustion engine, the device comprising:

• a tank that stores fuel;
• a fuel injection valve that supplies fuel to a cylinder;
• a fuel passage that supplies the fuel in the tank to the fuel injection valve;
• an electromagnetic valve that is provided in the fuel passage so as to open and close the fuel passage;
• a variable volume mechanism configured to vary a volume of a downstream-side fuel passage, the downstream-side fuel passage being a section of the fuel passage that is connected to a downstream side of the electromagnetic valve in a flow direction of the fuel in the fuel passage;
• and
• a processing circuitry that executes a fuel pressure control, wherein
• in the fuel pressure control, the electromagnetic valve is repeatedly opened and closed such that a fuel pressure in the downstream-side fuel passage falls within a range defined by an upper limit value and a lower limit value, and
• the processing circuitry is configured to execute a volume increasing process that operates the variable volume mechanism to increase a volume of the downstream-side fuel passage during the execution of the fuel pressure control.