Fuel Evaporation System: Operation
When the engine is not running, fuel tank vapor passes through the rollover valve and flows into the canister. When the engine is started, ECU controls EGR/canister purge solenoid. When ECU cuts power to solenoid, vacuum is applied and vapors are drawn into the intake manifold from canister.
A calibrated jet located in purge line to intake manifold meters the vapor flow into intake manifold. The rollover valve prevents fuel leakage in case of rollover.