__..--. -._ _^__. __--- -._ _..EMISSION CONTROL SYSTEMS
- Evaporative Emission Control Svsvem25-l 1
,VAPORATlVE EMISSION CON-
TROL SYSTEMIn order to prevent the escape of fuel vapor from the
fuel system into the atmosphere. the evaporative
emission control system consists of a charcoal
canister, a purge control solenoid valve, etc.
When the fuel vapors generated inside the fuel tank
fill the tank, they press and open the overfill limiter’s
valve and pass to the canister, where they are
absorbed into and accumulated by the charcoal.
Because the purge control solenoid valve is ON
(open) when the engine is running, as a
conse-
Non-TurboAir cleaner
Fuel injector
Canister
Charcoal
/Purge control tsolenoid valve r
RZSGAAB
quence of the purge air being taken in from the
canister in accordance with the intake negative
pressure (vacuum), the fuel vapors accumulated in
the canister are taken from the charcoal and are alsotaken into the intake manifold.
Note that the purge control solenoid valve is OFF
(closed) when the engine is cold and during idling,
and so fuel vapors are not taken into the intake
manifold at that time.
Overfill
limiter(Two-way valve)
Fuel check valveFilter
- Fuel vapor
*---- Purge air
--.25-14EMISSION CONTROL SYSTEMS
- Evaporative Emisson Control System
Pressure valveTo overfill
’ limiter
40
” Ball
Bail
\From fuel tank03E51fOVERFILL LIMITER (TWO-WAY VALVE)
The overfill limiter consists of a pressure valve and a vacuum
valve. The pressure valve is designed to open when the fuel
tank internal pressure has increased over the normal pressure
and the vacuum valve opens when a vacuum has been
producted in the tank.
FUEL CHECK VALVE
The fuel check valve is used to prevent fuel leaks if the vehicle
rolls over. This valve is connected in the fuel vapor line
(between canister and overfill limiter) and is installed on thefirewall.
The fuel check valve contains two balls, as shown in the
illustration. Under normal conditions, the fuel vapor passage in
the valve is opened, but if roll-over occurs one of the balls
closes the fuel passage, thus preventing fuel leaks.
FUEL FILLER CAPThe fuel filler cap is equipped with a relief valve to prevent the
escape of fuel vapor into the atmosphere.
.
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