Abstract: A control method and apparatus of an engine for driving a generator. When a weight W of a charcoal canister is greater than a predetermined value W.sub.1 ` and a vehicle runs, the engine is actuated. As the result of the actuation of the engine, when a gasoline vapor within a fuel tank is purged and the weight W of the charcoal canister is lower than a second predetermined value W.sub.2, a vacuum switching valve for purging the canister is turned off and the engine is stopped. Even when the vehicle runs while a battery is frequently charged by an external charger, the occurrence of a certain amount of the fuel vapor which can not be caught and collected by the charcoal canister can be prevented and a low pollution vehicle can be obtained. In place of the vehicle running state, a vehicle running distance, or a vehicle running time can be used. In place of the predetermined value W.sub.2, a fuel purge amount can be used.