Fuel tank installation

A fuel tank installation, comprising:

• a fuel tank with an expansion volume, a filler neck extending to the fuel tank for refueling the fuel tank, a fill vent line in communication with the fuel tank for venting the fuel tank during refueling, and operating vent means for venting the expansion volume disposed above a maximum fill level of the fuel in the fuel tank, said operating vent means including at least one operating vent line extending from at least one expansion volume within the fuel tank to a central penetration location and, at the central penetration location, together with the fill vent line, through a wall of the fuel tank, said central penetration location including an annular operating vent chamber to which said at least one operating vent line is connected, said annular operating vent chamber being in communication with the fill vent line extending around a space forming the inlet end of the fill vent line, which is larger in diameter than said operating vent line, so as accommodate the relatively large vent gas flow during refueling, the fill vent line serving during normal engine operation as liquid-gas separation chamber for the vent gases from the operating vent line.