Daihatsu F300 Service Manual page 1361

EMISSION CONTROL SYSTEM
EXHAUST GAS RECIRCULATION
(EGR) SYSTEM (US Specification Only)
The EGA system recirculates the exhaust gas into the intake
manifold in an optimum amount according to driving conditions
and coolant temperature.
Thus, this system retards the combustion, resulting in reduced
amount of NOx emission.
Coolant temperature
8/SV
Throttle valve
EGR vacuum modulator
opening angle
Below 39°C
Closed
Positioned below EGR Opens passage to
port atmosphere
Opens passage to
Above 40°C
Closed
* Positioned between
atmosphere
EGA
port
Closed passage to
atmosphere
**
Positioned above Closed passage to
EGA port atmosphere
REMARKS:
Exhaust gas
Closed
Not recirculated
Closed
Not recirculated
Closed Not recirculated
Open
Recirculated
Open
Recirculate volume
increase
At this stage, the EGA valve repeats its opening/closing as described below, depending upon the throttle valve opening and
exhaust gas pressure.
Exhaust gas pressure drops.
--+
Modulator opens.
--+
EGR valve closes.
.1-
i
EGA valve opens.
t-
Modulator opens.
f-
Exhaust gas pressure increases.
•• At this stage, the EGA valve remains open because of a negative pressure being applied to the EGA port, even when the modulator
opens to the atmosphere.
INSPECTION OF EGR SYSTEM
1. Preparation
Using a three-way connector, connect a vacuum gauge to
the hose betv:een the EGR valve and the EGR vacuum
modulator.
EC-22
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