Evaporative Emission Management For Vehicles

Evaporative emissions management for a vehicle having a fuel tank and a low-vacuum internal combustion engine, including hybrid electric vehicles, include first and second canisters with the second canister disposed between the first canister and atmosphere. A refueling valve routes fuel vapors from the fuel storage tank through the first canister, and to the second canister when the first canister becomes saturated, during refueling. Other than during refueling, the refueling valve is closed to route fuel vapors around the first canister and directly into the second canister. First and second purge valves are controlled during canister regeneration or purging so air from atmosphere is routed primarily through the second canister to the engine to purge the second canister before the purge valves are operated to route air from atmosphere through both the second and first canisters to purge the first canister.