Patent ID: 8757132

Claim:
A fuel vapor processor comprising: a fuel tank configured to reserve fuel; a canister containing adsorbent capable of adsorbing fuel vapor vaporized in the fuel tank; a separator receiving a fuel vapor-containing gas from the fuel tank and selectively passing the fuel vapor therethrough in order to divide the fuel vapor-containing gas into a first gas mainly containing the fuel vapor and a second gas having a fuel vapor density lower than the first gas; a regulator controlling the volume of the fuel vapor-containing gas supplied to the separator; and a suction unit configured to remove the fuel vapor from the canister and to suction the first gas from the separator in order to return the first gas into the fuel tank; wherein the second gas is introduced into the canister or is released into the atmosphere; and wherein the volume of the fuel vapor-containing gas supplied to the separator is determined based on known characteristics of relationships between the volume of the fuel vapor-containing gas supplied to the separator and the fuel vapor density of the second gas.