Evaporative Emissions System: Description and Operation

Evaporative Emission Control
The fuel tank incorporates a plastic vessel that limits the fill level and allows for 10 % fuel expansion. Tank venting is via a system of vapor tubes and a liquid/vapor separator in the tank to the charcoal canister, located in the left front wheel well. Vapor flow to the canister is controlled by an engine vacuum-operated bypass valve which allows vapor flow to the canister when the engine is operating. A pressure/vacuum relief valve prevents excessive pressure or vacuum from building in the fuel tank. Canister purging to the intake manifold is controlled by the ECM through an electric purge valve located at the canister.

Evaporative Emission Control:

Evaporative Flange
The top of the fuel tank incorporates a removable evaporative flange with three outlets. The center outlet incorporates a 2.5-3.0 psi pressure relief valve and is connected to a relief tube that vents to under the vehicle. The third outlet incorporates a rollover valve and connects to the charcoal canister. Electrical connection to the fuel pump module is made through the evaporative flange.

Evaporative Flange: