18
486 PL ENGINE
P
B) CARBON CANISTER
As fuel evaporates in the fuel tank hydrocarbons are discharged in the atmosphere. The legal requirements
regarding evaporative emissions can be satisfied with the application of carbon canister which store the
hydrocarbons from the fuel tank. The fuel tank is ventilated exclusively via this carbon canister.
Air is drawn through the carbon canister and into the engine for combustion. The entry of such air into engine
must be controlled, both to remain exhaust emissions within the desired limits as well as to ensure good
driveablity. For this, ECU activates canister purge valve. This valve controls the air /fuel mixture entering
engine from canister.
EVAPORATIVE EMISSION CONTROL SYSTEM
1.
INTAKE AIR
2.
THROTTLE VALVE
3.
INTAKE MANIFOLD (TO ENGINE)
4.
CANISTER PURGE VALVE
5.
SIGNAL FROM ENGINE MANAGEMENT
SYSTEM (ECU)
6.
CARBON CANISTER
7.
AMBIENT AIR
8.
FUEL VAPOURS IN TANK
9.
TANK PRESSURE VALVE
1
2
3
4
5
6
7
8
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9
Fig. 14




