Fuel tank device for vehicle having float valve and diaphragm valve

Abstract

A fuel tank device for a vehicle having a fuel tank, the device including a float valve mounted within the fuel tank, and a diaphragm valve connected to an air outflow passage of the float valve. The float valve includes a casing, and a float received in a float chamber in the casing for vertical movement for opening and closing the air outflow passage in a top wall of the casing in accordance with a change of a fuel liquid level in the fuel tank. The casing includes a removable bottom portion having a through hole. The diaphragm valve includes (a) a reference pressure chamber, (b) a fluid pressure chamber in communication with the air outflow chamber, (c) a fluid outflow passage provided at the fluid pressure chamber, (d) a fluid discharge chamber in communication with the fluid outflow passage, (e) an annular outer extension chamber connected to an outer periphery of the fluid discharge chamber, the outer extension chamber being greater in height than the flat fluid discharge chamber, (f) a fluid discharge passage connected to the outer extension chamber, and having an inner diameter generally equal to the height of the outer extension chamber, (g) a diaphragm separating the reference pressure chamber from the fluid pressure chamber, the diaphragm receiving a pressure of a fluid within the fluid pressure chamber for communicating the fluid pressure chamber with the fluid outflow passage, and (h) structure for urging the diaphragm into a position to interrupt the communication between the fluid pressure chamber and the fluid outflow passage.