Evaporative emission canister

WARNING: This page is about a different car, the 2003 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Spring-Loaded Float Closes Valve Tank Is Full Or If Car Rolls Over

Courtesy of SAAB-SCANIA OF AMERICA, INC.

The evaporative emission canister is located on the right-hand side of the tank and comprises a container filled with a special type of carbon pellets. Carbon pellets are used so that as little resistance as possible is obtained from the evaporative emission canister. The hydrocarbons that evaporate in the tank are passed to the evaporative emission canister. When refuelling, hydrocarbons and air from the tank are evacuated to the evaporative emission canister, which absorbs the hydrocarbons.

Separate lines connect the evaporative emission canister with the fuel tank, EVAP purge valve and shut-off valve. When the engine starts, air is drawn in through the shut -off valve to the evaporative emission canister and then via the purge valve into the intake manifold. The hydrocarbons are taken with it and are burned in the engine.

The evaporative emission canister absorbs approx. 70 g hydrocarbon for each full tank. The emission canister is purged while the car is being driven, the time it takes depends on the driving. The evaporative emission canister can absorb a maximum of approx. 125 g hydrocarbon.