Exhaust Emissions System - Fuel Evaporation: Operation

Fuel vapors are conveyed through the system to the carbon canister where they are absorbed by the activated carbon. During engine operation the vapors are drawn from the carbon canister into the intake manifold and into the engine. The three-way valve is used to slightly pressurize the tank, provide an air inlet to the tank, preventing any possible vacuum. The valve also acts as a safety exhaust to prevent tank overpressure. The check valves are in the system to prevent fuel leakage in the event of an accident.