Description |
Evaporative Emission Control System prevents fuel vapor stored in fuel tank from vaporizing into the atmosphere. When the fuel evaporates from the fuel tank, the vapor passes through vent hoses or tubes into canister filled with charcoal and the canister temporarily holds the vapor in the charcoal.
If ECM determines to draw the gathered vapor into the combustion chambers at certain operating conditions, it will use vacuum in the intake manifold to move it.
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 met.
Purge Control Solenoid Valve (PCSV)
Purge Control Solenoid Valve (PCSV) is installed in the passage connecting canister and intake manifold. It is a duty cycle control type solenoid valve 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 that the seal has been set.