US Patent 10473070 Fuel tank system

A fuel tank system is provided. In the main tank of the system, the end of a communication pipe is located above the end of a fuel introduction pipe inserted into the main tank. The end of a first pressure relief pipe at which a first cut-off valve is provided is located above the end of the communication pipe. In the auxiliary tank, the end of the communication pipe is located above the end of the fuel introduction pipe inserted into the auxiliary tank. In the auxiliary tank, the end of a second pressure relief pipe at which a second cut-off valve is provided is located above an end of a scavenging pipe.