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 vapors are vented by a vent line through roll over valve and to the carbon canister.
The roll over 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° angle, or more, from horizontal.
The carbon canister is filled with activated carbon. Fuel vapors from the tank are adsorbed by carbon when engine is not running. When engine is running faster than idle, fuel vapors are drawn into the engine and burned.