how does a vapor canister work?
<answer> When the vehicle is shut off, there is a pressure imbalance within the fuel tank caused by fuel being siphoned out, but no air being let back in to take up the empty space. The lower pressure in the gas tank promotes a greater rate of evaporation, letting some of the fuel become a gas. <context> The interior of the canister is filled with charcoal or carbon pellets. The input of the canister connects to the gas tank's vent port, while the output connects to the purge valve in the side of the vehicle's intake manifold. How does a Carbon Canister Work? When the vehicle is shut off, there is a pressure imbalance within the fuel tank caused by fuel being siphoned out, but no air being let back in to take up the empty space. The lower pressure in the gas tank promotes a greater rate of evaporation, letting some of the fuel become a gas.