Fuel Evaporation System: Operation
The fuel tank is fitted with a pressure/vacuum relief filler cap which allows excessive tank pressure to vent. It also allows air into tank if vacuum should become excessive due to a malfunction in fuel evaporation system. Fuel tank vapor is vented by a line through rollover valve to the charcoal canister.
The rollover valve is located in the vent line close to the fuel tank. Valve is designed to prevent fuel spillage if vehicle rolls over. Valve is open until vehicle is at a 45 degree angle, or more, from horizontal.
The charcoal canister is filled with activated charcoal. Fuel vapor from tank is adsorbed by charcoal when engine is not running. When engine is running faster than idle, fuel vapor is drawn into the engine and burned.