Page 212 of 1082
08-90000-00
Coolant temperature sensor
Measures the coolant
temperature and sends the
result to the engine ECU.
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.
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13-31793-01
E-EGR bypass valve Solenoid valve Drivien byVacuum
(Solenoid valve)
1. SPECIFICATION
Item
E-EGR valve Motor EGR response time 50 mS
Driven by DC motor
Valve EGR gas flow rate 120 Kg/h
Position sensor Sensing type Hall sensor
Supply voltage 5V ± 10%
Signal range 5% ~ 95%
Max. current consumption<15mA
E-EGR cooler Cooling capacity 8.3 kW or more
Coolin fin type Wavy fin
Coller type U-shaped
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13-4
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 D20DTF 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 decreased.
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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13-51793-01
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
60˚C or more), atmospheric pressure
(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.
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.
E-EGR valve
Receives the electric signal from the ECU to
control the valve.
EGR cooler
EGR bypass
Page 269 of 1082
14-6
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.
Page 271 of 1082
14-8
Engine ECU (D20DTF)
Post-injectionDifferential pressure sensor
Calculates the amount of PM
collected by reading the pressure
difference between before and
after the CDPF.Electric throttle body
Regulates the rate of air
intake.
CDPF
(DOC + DPF)Front temperature
sensor
Protects the
turbocharger.Rear temperature
sensor
Measures the
temperature of fuel
combustion.
2. COMPONENT
Oxygen sensor
Page 272 of 1082

14-91114-00
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
temperature of the exhaust gas is kept at 600℃. 1.
2.
<0070008d0047009b008f008c0047009b008c00940097008c00990088009b009c0099008c0047008c009f008a008c008c008b009a0047005d005700570b4500530047009b008f008c004700930090008d008c00470096008d0047006a006b0077006d004700
8a0088009500470089008c00470099008c008b009c008a008c>d. So the amount of fuel
post-injection is decreased.
<0070008d0047009b008f008c0047009b008c00940097008c00990088009b009c0099008c0047008b009900960097009a0047009c0095008b008c00990047005d005700570b4500530047009b008f008c004700990088009b008c00470096008d0047009900
8c008e008c0095008c00990088009b0090009600950047008a>an be decreased. So the
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.
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14-10
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
<009a008c0095009a00960099005500470070008d0047009b008f008c0047009b008c00940097008c00990088009b009c0099008c00470090009a00470093008c009a009a0047009b008f008800950047005d005700570b4500530047009b008f008c004700
8800940096009c0095009b00470096008d004700970096009a>t-injection is increased to
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.
4. POST-INJECTION AND AIR MASS CONTROL