FUEL PRESSURE ESTIMATION SYSTEM

A fuel pressure estimation system estimates a fuel pressure variable on a fuel pressure in a supply pipe for an engine apparatus including an engine having a fuel injection valve, and a fuel supply device having a fuel pump that supplies the fuel in a fuel tank to the supply pipe, and includes a storage device and an execution device. The storage device stores a first mapping that receives, as an input, first input variables including a pump variable, a consumption flow rate variable on a consumption flow rate of the fuel, and a property variable on a property of the fuel, and outputs the fuel pressure variable. The execution device acquires the first input variables and estimates the fuel pressure variable by applying the first input variables to the first mapping.