Description |
The Evaporative Emission Control System prevents fuel vapor stored in fuel tank from vaporizing into the atmosphere. When the fuel evaporates in the fuel tank, the vapor passes through vent hoses or tubes to a canister filled with charcoal.
The canister temporarily holds the vapor in the charcoal. The ECM will control the system in order to draw the gathered vapor into the combustion chambers during certain operating conditions. Engine manifold vacuum is used to draw the vapor into intake manifold.
Schematic Diagram |
1. Air cleaner 2. Delivery pipe & injector 3. Engine 4. Purge control solenoid valve (PCSV) 5. Fuel tank air filter |
6. High pressure fuel pump
7. Fuel filler hose 8. Fuel filler cap 9. Fuel tank 10. Low pressure fuel pump |
Canister
Canister is filled with charcoal and absorbs evaporated vapor in fuel tank. The gathered fuel vapor in canister is drawn into the intake manifold by the ECM/PCM when appropriate conditions are set.
Purge Control Solenoid Valve (PCSV)
Purge Control Solenoid Valve (PCSV) is installed in the passage connecting canister and intake manifold. It is a duty type solenoid valve and is operated by ECM/PCM signal.
To draw the absorbed vapor into the intake manifold, the ECM/PCM will open the PCSV, otherwise the passage remains closed.
Fuel Filler Cap
A ratchet tightening device on the threaded fuel filler cap reduces the chances of incorrect installation, which would seal the fuel filler. After the gasket on the fuel filler cap and the fill neck flange contact each other, the ratchet produces a loud clicking noise indicating the seal has been set.