Liquid Vapor Separator: Description and Operation

Fuel Tank Vapor Vent Valve:

Fuel Tank Fuel/Vapor Separator Operation:

PURPOSE
Permits fuel vapors to be vented to the charcoal canister, while restricting liquid fuel.
In the event of vehicle roll-over, the float closes off the valve, preventing fuel from escaping and saturating the charcoal canister.

OPERATION
Fuel vapors generated, enter the valve from the bottom, rise upward past the float, and out through a single vapor line to the carbon canister.

If liquid fuel enters the valve assembly, the float will rise upward and close the orifice. As fuel is drained back into the fuel tank, the spring attached to underside of valve pulls the float downward, exposing the orifice.

If the fuel vapor line to the canister becomes kinked or plugged, causing extreme pressures to build inside fuel tank, the vapor valves purge port opens to provide pressure relief.