Evaporative Emission Control Canister: Description and Operation

Charcoal Canister

Charcoal Canister - All except NAS







Charcoal Canister - NAS







The charcoal canister is located on the forward edge of the fuel tank on the right hand side. It is attached to the fuel tank with two bolts.

The canister on all except NAS (ROW) vehicles has a capacity of 1200cc (73.2 cu.in).

The canister on NAS vehicles has a capacity of 3000cc (183 cu.in).

The canister has three ports which allow for the attachment of the atmospheric vent hose, the purge hose and the tank vent hose. On NAS vehicles the atmospheric vent hose connection allows for the attachment of the DMTL pump.

The canister contains a bed of activated charcoal or carbon. The charcoal is produced using special manufacturing techniques to treat the charcoal with oxygen. The oxygen treatment opens up millions of pores between the carbon atoms resulting in a highly porous charcoal with a very large effective surface area which is capable of absorbing large quantities of fuel vapor. Once treated the charcoal is known as 'activated' carbon or charcoal. The charcoal canister on NAS vehicles uses a higher grade charcoal to meet the requirements of LEV2 emission regulations.