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

A valve assembly comprising:

• a valve body defining a cavity and an outlet in fluid communication with the cavity;
• a seat separating the cavity into a first cavity portion and a second cavity portion, with the seat including a platform defining an aperture that provides fluid communication between the first and second cavity portions;
• and
• a cover device disposed in the first cavity portion, with the cover device defining at least one hole, and with the cover device movable between a rest position engaging the platform to restrict 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 when performing a diagnostic test, the method comprising:

• providing a valve body including a first cavity portion and a second cavity portion separated by a seat;
• restricting 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.