Evaporative emission control in battery powered vehicle with gasoline engine powered generator

A method of operating a fuel evaporative emission control system in a plug-in hybrid vehicle driven by a battery powered electric motor with a supplemental gasoline engine powered-electric generator operated on-demand for supplemental electric power for the vehicle, where the vehicle comprises a gasoline fuel tank, a fuel vapor vent passage from the fuel tank to a fuel vapor adsorption canister, a first air and fuel vapor flow passage from the canister for venting the canister and for introduction of purge air to the canister to purge fuel vapor from the canister, and a second air and fuel vapor flow passage from the canister for passage of purge air and purged fuel vapor from the canister to an air induction system of the engine, the method comprising:

• opening the first and second air and fuel vapor passages during engine operation;
• opening the first air and fuel vapor passage, but not the second air and fuel flow passage, when the vehicle is not operating and the gasoline is being added to the fuel tank;
• and
• closing both of the first and second air and fuel vapor passages for preventing diurnal vapor generation and preventing bleeding of fuel vapor from the canister when the vehicle is not in operation and when the vehicle is in operation but the gasoline engine is not being operated.