Valve assembly for a tank of a vehicle and a method of creating a vacuum in the tank

A valve assembly for a tank of a vehicle, the assembly comprising:

• a valve body adapted to be attached to the tank, with the valve body defining a cavity along a longitudinal axis and defining an outlet in fluid communication with the cavity for venting the tank;
• a seat disposed in the cavity of the valve body and separating the cavity into a first cavity portion and a second cavity portion, with the seat including a platform defining an aperture along the longitudinal axis to provide fluid communication between the first and second cavity portions;
• and
• a cover device disposed between the seat and the outlet, with the cover device defining at least one hole through the cover device, and with the cover device movable between a rest position engaging the platform to minimize fluid communication between the aperture and the hole and an actuated position spaced from the platform to increase fluid communication between the aperture and the hole when a vacuum is created in the first cavity portion;
• wherein the first and second cavity portions have a substantially equal first pressure when the cover device is in the rest position before the vacuum has been created, and the first cavity portion obtains a second pressure less than the first pressure of the second cavity portion when the vacuum is created in the first cavity portion by gaseous fluid being removed from the first cavity portion through the outlet while the cover device is in the rest position which causes the cover device to move to the actuated position to increase fluid communication between the first and second cavity portions.

A method of creating a vacuum in a tank of a vehicle when performing a diagnostic test, the method comprising:

• providing a valve body adapted to be attached to the tank, with the valve body including a first cavity portion and a second cavity portion separated by a seat;
• minimizing flow of gaseous fluid between a hole in a cover device and an aperture of the seat when the cover device is in a rest position engaging the seat;
• removing gaseous fluid from the first cavity portion of the valve body out through an outlet of the valve body while the cover device is in the rest position to create the vacuum in the first cavity portion and a pressure difference between the first and second cavity portions;
• moving the cover device to an actuated position spaced from the seat in response to the vacuum creating the pressure difference between the first and second cavity portions;
• and
• increasing flow of the gaseous fluid between the hole in the cover device and the aperture of the seat when the cover device is in the actuated position to increase flow of the gaseous fluid between the first and second cavity portions.