Mitsubishi MOTORS Space Runner 1999 Workshop Manual Supplement page 669

17-18
ENGINE AND EMISSION CONTROL –
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
GENERAL INFORMATION
The exhaust gas recirculation (EGR) system lowers
the nitrogen oxide (NOx) emission level. When the
air/fuel mixture combustion temperature is high, a
large quantity of nitrogen oxides (NOx) is generated
in the combustion chamber. Therefore, this system
recirculates part of emission gas from the exhaust
OPERATION
The EGR valve is being closed and does not
recirculate exhaust gases under one of the following
conditions. Otherwise, the EGR valve is opened
and recirculates exhaust gases.
SYSTEM DIAGRAM
<GDI>
Emission Control System
port of the cylinder head to the combustion chamber
through the intake manifold to decrease the air/fuel
mixture combustion temperature, resulting in
reduction of NOx.
The EGR flow rate is controlled by the EGR valve
so as not to decrease the driveability.
The engine coolant temperature is low.
The engine is at idle.
The throttle valve is widely opened.
Throttle body
EGR
valve
Control
relay
Battery
Engine-ECU
Air flow sensor
Engine coolant
temperature sensor
Crank angle sensor
Throttle position sen-
sor
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