Evaporative Emissions System: Description and Operation

EVAP Control System Operation:

PURPOSE
An evaporative control system is used to reduce emissions of fuel vapors into the atmosphere by evaporation and to reduce unburnt hydrocarbons emitted by the engine.

CONSTRUCTION
The system consists of a EVAP Purge Solenoid, a Charcoal Canister, a Pressure Vacuum Filler Cap, and a Rollover and Pressure Relief Valve.

OPERATION
The evaporative emission system prevents gasoline vapors in the fuel system from escaping into the atmosphere. When the vehicle is not running, fuel in the fuel tank evaporates. The vapors travel through vent hoses or tubes to be stored in the charcoal canister. Once the vehicle is running, these vapors are drawn into the engine and consumed with combustion gases.