Patent ID: 8312867

Claim:
An engine system for a vehicle, comprising: an internal combustion engine including an air intake passage; a fuel storage tank; an evaporator configured to receive a fuel mixture from the fuel storage tank via a fuel passage and to vaporize a higher volatility fuel from a lower volatility fuel contained in the fuel mixture; a vapor separation system including at least a first adsorption canister and a second adsorption canister arranged in parallel; a vapor passage fluidly coupling a vapor formation region of the evaporator with an inlet of each of the first and second adsorption canisters of the separation system; a fuel vapor purging passage fluidly coupling the air intake passage of the engine with an outlet of each of the first and second adsorption canisters; and a control system configured to: operate the evaporator to vaporize the higher volatility fuel from the lower volatility fuel; and during a first mode, pass the higher volatility fuel through the first canister to adsorb a hydrocarbon fraction of the higher volatility fuel at the first canister while purging fuel vapors from the second canister to the air intake passage of the engine; and during a second mode, pass the higher volatility fuel through the second canister to adsorb the hydrocarbon fraction of the higher volatility fuel at the second canister while purging fuel vapors including the hydrocarbon fraction adsorbed during the first mode from the first canister to the air intake passage of the engine.