Patent ID: 8360013

Claim:
A fuel tank system that stores a blended fuel obtained by blending ethanol with gasoline as a fuel to be supplied to an internal combustion engine, comprising: a fuel tank for storing the blended fuel; a pump configured to suck the blended fuel in the fuel tank, mix water with the blended fuel sucked by the pump, separate the blended fuel mixed with the water into the gasoline and an ethanol-water mixture, and pressure-feed the separated gasoline and ethanol-water mixture; a separation tank provided inside the fuel tank, and storing the gasoline and the ethanol-water mixture pressure-fed by the pump in a state separated from each other and in a pressurized state; a gasoline drawing device configured to draw the gasoline out of the separation tank via a first on-off valve from above an interface between the gasoline and the ethanol-water mixture stored in the separation tank; and an ethanol drawing device configured to draw the ethanol-water mixture stored in the separation tank out of the separation tank via a second on-off valve from below the interface, wherein the pump is located inside the fuel tank and is located fully outside the separation tank.