to canister 22 so that vapor storage could begin again there are many advantages to the invention over the conventional evap system foremost there is no effect on driveability or exhaust emissions at all since no purged vapor mixture is fed to the engine a canister is still used but there would none of the problems of air and liquid contamination that can occur when there is an opening for outside purge air to be pulled through as with a conventionally purged canister nor would there be the problems of designing a granule bed to give proper vapor and air flow during purge furthermore the system of the invention since it vacuum purges rather than air purges would lend itself very well to any suitable means other than a charcoal canister 22 that would separate the air from the fuel vapor or hydrocarbon content of an air fuel vapor mixture for example a membrane that separated hydrocarbon components from a fuel vapor and air mixture could conceivably be used in place of charcoal canister 22 to separate and gather the fuel vapors apart from the air with pump 42 being used to power the separation process and purge the fuel vapors alone to tank 14 since the valving and feed lines are basically conventional and the canister 22 is not greatly different from a conventional canister the system could be easily incorporated into existing vehicles there is real potential for an increase in purge efficiency especially in the purge after fuel refilling since the canister will be warm from the recent vapor loading and the recently added fuel will be relatively cool this would aid both the vapor desorbtion.