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1520-00
Electric fan
Circulates the fresh air forcibly to exchange heat
with the radiator core fin.
Radiator
Releases heat through fins and cools down the hot
coolant as the coolant passes through the tube of the
radiator core.
Coolant temperature sensor
Measures the coolant
temperature and sends the
result to the engine ECU.
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1793-00
1. SPECIFICATION
Item Specification
E-EGR valveMotorEGR response time 50 ms
Driven by DC motor
Valve EGR gas flow rate 120 kg/h
Cooling capacity 8.3 kW or more
Cooling fin type Wavy fin
Cooler type U-shaped
E-EGR bypass valve Solenoid valve Drivien byVacuum
(Solenoid valve)
E-EGR cooler
Position sensorSensing type Hole sensor
Supplied voltageMaximum signal
range5% ~ 95%
Maximum power
consumption
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1. SYSTEM DESCRIPTION
1) Overview
The EGR (Electric-Exhaust Gas Recirculation) valve reduces the NOx emission level by recirculating
some of the exhaust gas to the intake system.
To meet Euro-V regulation, the capacity and response rate of E-EGR valve in D20DTR engine have been
greatly improved. The EGR cooler with high capacity reduces the Nox, and the bypass valve reduces the
CO and HC due to EGR gas before warming up.
Also, the engine ECU adjusts the E-EGR opening by using the air mass signal through HFM sensor. If
the exhaust gas gets into the intake manifold when the EGR valve is open, the amount of fresh air
through HFM sensor should be decresed.
Benefits of E-EGR valve
Improved accuracy and response through electric control
Feedback function (Potentiometer)
Preventing chattering of EGR valve and improved durability
Self-cleaning function -
-
-
-
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1793-00
E-EGR valve
Receives the electric signal from the ECU to
control the valve.
E-EGR cooler and bypass valve
The cooler lowers the high temperature of the
exhaust gas and the bypass valve directly
supplies the exhaust gas to the intake duct
without passing through the EGR cooler to
reduce the emission of exhaust gas before
warming up the engine.
2) Location and Components
HFM sensor
Used as a main map value to control the EGR.
The coolant temperature, engine rpm, engine
load, intake air temperature (HFM: decreased at
(atmospheric pressure sensor: altitude
compensation) are used as auxiliary map values.
EGR pipe
Transports the exhaust gas from the EGR cooler
and EGR bypass valve to the intake duct.
See the section "Engine control" for E-EGR
valve control logic.
EGR cooler
EGR bypass
For details, see the section "Engine control". *
Page 428 of 600
Excessive overload of CDPF (warning lamp illuminated)
If the vehicle is driven at a speed of 5 to 10 km/h for an extended period of time, the soot
accumulated in the CDPF cannot be burned as the CDPF cannot reach the regeneration
temperature. Then, an excessive amount of soot can be accumulated in the CDPF.
This case is much worse than the simple over-load of the CDPF. To inform this to the driver, the
engine warning lamp comes on and the engine power is decreased to protect the system.
To solve this problem, blow soot between the engine and exhaust system several times and erase
the related DTC. Then, check if the same DTC is regenerated again. If so, check the DTC related to
the differential pressure sensor. 1.
2.
3.
Illuminating
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Differential pressure
sensor
Calculates the amount of
PM collected by reading the
pressure difference between
before and after the CDPF.Engine ECU
DCM 3.7
Post-injectionThrottle
valve
Regulates the rate of air
intake.
CDPF
DOC+DPFFront temperature
sensor
Protects the turbocharger.Rear temperature sensor
Measures the temperature
of fuel combustion.
2. COMPONENT
For details, refer to section "Engine Control". *
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2412-02
3. INPUT/OUTPUT DEVICES
Front temperature sensor: This sensor is installed at the inlet of DOC and detects whether the
DOC can burn (oxidize) the post-injected fuel or not.
Rear temperature sensor: This sensor is installed at the inlet of DPF and monitors that the 1.
2.
post-injection is decreased.
amount of fuel post-injection is increased. -
-
Differential pressure sensor: This sensor checks the amount of PM collected by calculating the
pressure difference between before and after the CDPF.
Electric throttle valve: This valve reduces the intake air flow to raise the temperature of the exhaust
gas when the CDPF is operating during idling. 3.
4.
Page 432 of 600

4. POST-INJECTION AND AIR MASS CONTROL
A DPS (Differential Pressure Sensor) measures the pressure difference between before and after the
CDPF and detects whether the soot is collected in the CDPF or not. If PM is collected in the CDPF (In
this case the pressure difference between before and after the CDPF exceeds the specified value.
Normally, the system sends the signal when the driving distance becomes approx. 600 to 1,200 km), the
temperature of exhaust gas is increased and the post-injection is started for regeneration. The amount of
fuel post-injection is controlled by the exhaust gas temperature measured by the rear temperature
increase the regeneration temperature. Otherwise, the fuel injection amount is decreased or the fuel is
not injected.
When the engine is running with low load, the intake air amount is also controlled as well as fuel injection
amount. This function is used to increaser the combustion temperature by increasing the amount of fuel
post-injection with the lowest air amount within the specified control logic.