ENGINE AND EMISSION CONTROL -
Engine and Emission Control System
<4D5-Step III>
EGR solenoid valve No.1
EGR solenoid valve No.2
17-3
EXHAUST GAS RECIRCULATION (EGR) SYSTEM <4D5-step
III
>
GENERAL INFORMATION
The electronically-controlled EGR system consists
of an EGR valve, a vacuum pump, EGR solenoid
valves Nos.1 and 2, EGR valve position sensor
and engine-ECU and various sensors.
The EGR valve is controlled by the negative
pressure inside the valve, which is controlled by
EGR solenoid valves Nos.1 and 2.
In order to obtain EGR amount corresponding to
each operating condition, the appropriate opening
of the EGR valve is calculated based on the input
signal from each sensor.
Feedback control of the EGR solenoid valves No.
1 and No. 2 operation is carried out based on the
signal from EGR valve position sensor so that the
opening of the EGR valve can be quickly adjusted
to the target angle.
In this way, the EGR is controlled to reduce NOx
emissions
while
maintaining
good
engine
performance.
SYSTEM DIAGRAM
EGR valve
Boost air temperature sensor
A/C switch
Crank angle sensor
Vehicle speed sensor
Engine coolant temperature
sensor
Accelerator pedalposition
sensor
EGR
solenoid
valve No. 1 (ON-
OFF control)
Fuel temperature sensor
Barometric pressure sensor
Boost pressure sensor
EGR solenoid
valve No. 2 (ON-
OFF control)
EGR valve posi-
tion sensor
Engine-
ECU
Vacuum pump
COMPONENT LOCATION
