Evaporative Emissions System: Description and Operation

Fig. 126 Evaporative System:

This system stores fuel vapor generated by the fuel tank in the cannister when the engine is not running. The fuel vapor is stored in the cannister until it is drawn into the combustion chamber and burned when the engine is started.
The components that make up the evaporative emission control system are the: air flow meter, charcoal cannister, check and cut valve, engine control unit, ignition coil, fuel/vapor separator, purge control solenoid valve, two-way check valve, and a coolant temperature sensor.



CHARCOAL CANISTER

The charcoal cannister stores gasoline vapors when the engine is not running.

CHECK AND CUT VALVE

The check and cut valve releases excessive pressure or vacuum in the fuel system and vents it to/from the atmosphere.

ENGINE CONTROL UNIT

The engine control unit detects signals from input sensors and switches and controls the purge control solenoid valve.

FUEL/VAPOR SEPARATOR

The fuel/vapor separator prevents liquid fuel from entering the charcoal cannister.

PURGE CONTROL SOLENOID VALVE

The purge control solenoid valve is used to control the vacuum to the charcoal cannister.

TWO-WAY CHECK VALVE

Controls pressure in the fuel tank.