Evaporative Emissions System: Description and Operation

PURPOSE
The Evaporative Emissions (EVAP) system prevents the escape of fuel vapors to the atmosphere under hot soak and engine off conditions by storing them in the EVAP canister.

OPERATION

Fuel Vapor Flow To The Canister
Fuel vapors trapped in the fuel tank are vented through the EVAP valve. Fuel vapors flow through fuel tank vent tubes to the EVAP canister.

Fuel Vapor Flow To The Intake Manifold
The stored fuel vapors are purged from the EVAP canister to the intake manifold while the vehicle is being operated.

EVAP System Control
The Powertrain Control Module (PCM) operates the EVAP canister purge valve, allowing the stored fuel vapors to be drawn into the intake manifold for combustion.

CONSTRUCTION
The Purge Flow (PF) system consists of, fuel tank filler cap, fuel tank filler pipe, fuel tank vent tubes, EVAP valves, fuel tank, purge flow sensor EVAP canister purge valve and EVAP canister.