Fuel tank breathing system (Fuel delivery system)

Fuel tank breathing system

1. Filler cap
2. Evaporative emission canister purge valve
3. Evaporative emission canister
4. Filler neck breather pipe
5. Fuel tank
6. Vent pipe to evaporative emission canister
7. Two-way valve

FUEL TANK BREATHING SYSTEM

When filling the fuel tank, air trapped in the fuel tank by the rising fuel level is allowed to vent to the top of the filler neck by a separate breather pipe.

With the filler cap in place, fuel tank breathing is via a two-way breather valve which allows expanding fumes to exit the tank. Fumes are directed via a two-way valve to the evaporative emission canister where they can be purged into the engine via the evaporative emission canister purge valve.