Todays evaporative emissions, are greatly reduced by, sealed fuel-tank caps and the so-called evaporative emission control system.
In the heart of the evaporative emission system is a canister of activated charcoal; capable of holding up to 35 percent of its own weight in fuel vapor. In operation, fuel-tank vapors flow from the sealed fuel tank to a vapor separator; which returns raw fuel to the tank and channels fuel vapor through a purge valve to the canister. The canister acts as a storehouse; when the engine is running, the vapors are drawn by the resultant vacuum from the canister; through a filter, and into the combustion chamber, where they are burned.
Improvements in combustion efficiency are effected by; computerized control over the whole process of combustion. This control ensures the most efficient operation of the systems described above. In addition, computer-controlled fuel-injection systems ensure more precise air-fuel mixtures; creating greater efficiency in combustion and lower generation of pollutants.