Fuel tank system and puncture detection method

摘要

A fuel tank system includes: a fuel tank; a canister; a vent pipe; a valve member that is provided at the vent pipe and is sectioned into a tank-side main chamber, a canister-side main chamber and a back pressure chamber; a pipe configured to open an interior of the canister to the atmosphere; a negative pressure pump that is provided at the pipe, and applies negative pressure through the canister and the vent pipe to a fuel tank interior; a judging means for judging absence/presence of perforation of the fuel tank from behavior of air pressure at a time when negative pressure is generated at the negative pressure pump; and a negative pressure application path that communicates the pipe with the back pressure chamber, and that is configured to apply negative pressure from the negative pressure pump to the back pressure chamber without the negative pressure going through the canister.