Evaporative Emissions System: Description and Operation
The evaporative emission fuel vapor management system consistsof an evaporative emission canister and a fuel vapor management
valve. A combination of plastic pipes and rubber hoses connect
the canister to the fuel tank and the vapor management valve to
the intake manifold.
In addition, the fuel vapor management system uses a canister
vent solenoid and a fuel tank pressure sensor which are used
during the engine management system on board diagnostic
routines.
Evaporative Emissions:
When the vapor management valve is closed, the fuel tank is
vented into the canister through the fuel tank roll-over valve.
The canister absorbs the fuel vapor and prevents the release of
hydrocarbons into the atmosphere. When the vapor management
valve is opened, the canister is exposed to the intake manifold
vacuum and the fuel vapor deposits are drawn into the manifold
where they mix with the incoming air/fuel charge.
The evaporative emission fuel vapor management system is
controlled by the powertrain control module according to
calibrated data tables.