Evaporative Emissions System: Description and Operation

The evaporative emission system prevents the escape of fuel vapors to the atmosphere under hot soak and engine OFF conditions by storing the vapors in a Evaporative Emissions (EVAP) canister. The system also controls the purging of stored vapors from the evaporative emissions canister to the engine, where they are burned.

Fill limiting is accomplished through fuel tank filler pipe configuration and/or internal vent lines within the fuel tank filler pipe and fuel tank. The fill limiting system is designed to permit an air space of approximately 10 to 12 percent when the fuel tank is filled to capacity. This air space provides for thermal expansion of fuel and is necessary for proper function of the in-tank vapor vent system.


THE FUEL TANK EVAPORATIVE EMISSION SYSTEM CONSISTS OF:
- Fill control/vapor vent system
- Fuel tank filler cap
- Evaporative emission valve

THE ENGINE EVAPORATIVE EMISSION SYSTEM CONSISTS OF:
- Evaporative emission hoses
- Evaporative emissions canister
- Evaporative emission tube shut off valve
- Evaporative emission canister purge solenoid