Patent ID: 7827972

Claim:
An apparatus for controlling an internal pressure of a fuel tank comprising: an adsorption/desorption device capable of selectively absorbing or desorbing air components within vapor; and a vapor passage for communicating the adsorption/desorption device with an upper space within the fuel tank; wherein the adsorption/desorption device and the vapor passage do not communicate with the external atmosphere; a pressure detecting device for detecting the internal pressure of the fuel tank; and a pressure regulating device in the vapor passage disposed between the fuel tank and the adsorption/desorption device for controlling and maintaining the pressure applied to the adsorption/desorption device, wherein the pressure regulating device comprises a dual-direction pump capable of producing a gaseous stream in a first direction from the fuel tank toward the adsorption/desorption device and a gaseous stream in a second direction from the adsorption/desorption device toward the fuel tank opposite to the first direction; a controller causing the pump to pressure-feed the vapor in the first direction until the internal pressure of the fuel tank is in equilibrium with atmospheric pressure, such that a part of air components contained in the vapor and corresponding to pressure that exceed atmospheric pressure is adsorbed by the adsorption/desorption device when the pressure detecting device detects that the internal pressure of the fuel tank is higher than the atmospheric pressure; and the controller causing the pump to pressure-feed the vapor in the second direction until the internal pressure of the fuel tank is in equilibrium with atmospheric pressure, such that an amount of air components corresponding to a pressure less than atmospheric pressure is desorbed from the adsorption/desorption device when the pressure detecting device detects that the internal pressure of the fuel tank is lower than atmospheric pressure.