METHOD AND DEVICE FOR PURGING A FUEL TANK

摘要

A method for purging a fuel tank includes providing a three-way valve connected to the fuel tank via a first purging line, connected to a second purging line opening into a suction duct and connected to a third purging line opening into an adsorption container. A first path can be released in the three-way valve, based on the pressure inside the fuel tank exceeding a first predetermined opening pressure inside the fuel tank and the engine being in operation, such that the fuel vapours are caused to be purge out of the fuel tank into the suction duct. A second path can also be released in the three-way valve, based on the pressure inside the fuel tank exceeding a second predetermined opening pressure inside the fuel tank and the engine being not in operation, such that the fuel vapours are caused to be purged out of the fuel tank into the adsorption container.

主权项

1. A method for purging a fuel tank arranged in a motor vehicle, the method comprising: providing a three-way valve having first, second and third terminals, the first terminal being connected to the fuel tank via a first purging line, the second terminal being connected to a second purging line which opens into a suction duct of an internal combustion engine disposed downstream from a throttle device, the third terminal being connected to a third purging line which opens into an adsorption container configured to adsorb fuel vapours, the adsorption container being connected to a fourth purging line which is lockable and which opens into the suction duct, the adsorption container being further connected to an environment of the vehicle via a lockable ambient line so as to release air freed from fuel vapours and to receive ambient air;
determining, by a unit associated with the fuel tank and configured to detect an internal fuel tank pressure of the fuel tank, the pressure inside the fuel tank; releasing a first path in the three-way valve, based on the pressure inside the fuel tank exceeding a first predetermined opening pressure inside the fuel tank and the internal combustion engine being in operation, such that the first and second terminals are connected and cause the fuel vapours to be purged out of the fuel tank into the suction duct via the first and second purging lines, the first path being closed again based on the pressure inside the fuel tank falling below a first predetermined closing pressure inside the fuel tank; and releasing a second path in the three-way valve, based on the pressure inside the fuel tank exceeding a second predetermined opening pressure inside the fuel tank and the internal combustion engine being not in operation, such that the first and third terminals are connected and cause the fuel vapours to be purged out of the fuel tank into the adsorption container via the first and third purging lines, the second path being closed again based on the pressure inside the fuel tank falling below a second predetermined closing pressure inside the fuel tank.