Patent ID: 8191536

Claim:
A method of operating an evaporative purge system for an engine of a vehicle propulsion system, comprising: during a first condition, loading at least a first fuel vapor storage canister with fuel vapors from a fuel tank via a first fuel vapor passage and inhibiting fuel vapors from passing through a second fuel vapor storage canister; during a second condition, purging fuel vapors stored by at least the first fuel vapor storage canister to the engine; during a third condition, loading the second fuel vapor storage canister with fuel vapors from the fuel tank via the first fuel vapor passage and inhibiting fuel vapors from passing through the first fuel vapor storage canister; during a fourth condition, purging fuel vapors stored by the second fuel vapor storage canister to the engine without purging fuel vapors stored in the first fuel vapor storage canister; and deactivating the engine during the first and third conditions and operating the engine to combust the purged fuel vapors during the second and fourth conditions, and where the fourth condition occurs before the second condition after an engine start.