Evaporative Check Valve: Description and Operation

Vapor Vent:

Purpose
To prevent liquid fuel from passing to the evaporative emission canister. The vapor space also allows for thermal expansion of the fuel.

Operation
Fuel vapor in the fuel tank is vented to the evaporative emission canister through the evaporative emission valve, which is mounted in a rubber grommet at a central location in the upper surface of the fuel tank. A vapor space between the fuel level and the fuel tank upper surface is combined with a small orifice and float shut-off valve in the evaporative emission valve.