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How Does a Carbon Canister Work?


What is a Carbon Canister?

Carbon Canisters are devices found in automobiles designed to decrease the amount of air pollution the vehicle creates while at the same time increasing its fuel efficiency. Even when the vehicle’s engine is turned off, hydrocarbons are produced. This occurs in the form of fuel vapor rising in the fuel tank. Carbon Canisters trap that vapor rather than allow it to escape the fuel tank, feeding it back into the engine.


Carbon Canisters are rectangular shaped boxes that sit apart from the fuel tank next to the throttle in most vehicles. There is an input port and an output port, with the two ports side by side. There are three chambers inside the canister, running in sequence from the intake to the outtake. 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.