9-5 Sport Wagon (9600) V6-3.0L Turbo (B308) (2003)
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3. Fuel is filled into the tank. Together with the fuel is also a small amount of air from the filler pipe ejector. Gaseous hydrocarbons are present above
the surface of the fuel.
As the fuel level rises, the added air will be evacuated together with the gaseous hydrocarbons through a float valve fitted in the top of the tank.
The vapor then passes to the EVAP emission canister where the hydrocarbons are absorbed. The air, which cannot be absorbed, passes from the
emission canister to the surrounding air via a vent pipe leading up to the wheel housing at the side of the filler pipe.
There is a shut-off valve fitted at the top of the purge pipe. The shut-off valve can close the connection between the EVAP canister and the
surrounding air and is used only for OBD II diagnosis. (Cars with ORVR without tank integrity diagnosis are not equipped with a shut-off valve.)
The float valve also acts as a roll-over valve and closes if the car tips over.
4. When the tank is almost full (approx. 95%), the float valve will close one step, whereby the evacuation of air and gaseous hydrocarbons is greatly
restricted.
The pressure in the tank therefore increases as more fuel is filled.
