Evaporative Emissions System - VOLKSWAGEN: Operation

Expanded fuel, caused by high ambient temperatures, and fuel vapors pass through a vent line to an expansion chamber. Liquid fuel passing into the expansion chamber is returned to the main fuel tank as fuel is drawn from the main tank during normal operation. Fuel vapors pass from the expansion chamber, through a vent line, to the activated charcoal canister where they are absorbed by activated charcoal. When the engine is running, air is forced into the charcoal canister through the pressure line connected between the engine blower assembly and the canister. The fuel vapors are drawn from the canister, through a vacuum line, to the carburetor air cleaner and into the intake manifold where they enter the combustion system and are burned. This action purges the activated charcoal and renews its storage capacity.