System Description

The evaporative emission control system is used to reduce hydrocarbons emitted to the atmosphere from the fuel system. This reduction of hydrocarbons is accomplished by activated char- coals in the carbon canister.
The fuel vapor from the sealed fuel tank is led into the canister which contains activated carbon and the vapor is stored there when the engine is not running.
The canister retains the fuel vapor until the canister is purged by the air drawn through the bottom of the canister to the intake manifold when the engine is running. When the engine runs at idle, the purge control valve is closed.
Only a small amount of stored vapor flows into the intake manifold through the constant purge orifice. As the engine speed increases, and the throttle vacuum rises higher, the purge control valve opens and the vapor is sucked into the intake manifold through both the main purge orifice and the constant purge orifice.
The canister purge is also controlled by the E.C.U. and vacuum cut solenoid valve, according to warm-up conditions or driving conditions.
Refer to "E.G. R. & Canister Purge Control" of E.C.C.S. SYSTEM DESCRIPTION.
Evaporative purge control (E.P.C.) valve is installed in the purge line at the intake manifold, which controls the flow of purge air in proportion to intake air quantity.