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13-71793-00
2) Input/Output Devices
3) Control Logic
The EGR system controls the EGR amount based on the map values shown below:
Main map value: Intake air volume
Auxiliary map value: ※
※
Compensation by the coolant temperature
Compensation by the atmospheric pressure: Altitude compensation
Compensation by the boost pressure deviation (the difference between the requested value
and the measured value of boost pressure)
Compensation by the engine load: During sudden acceleration
Compensation by the intake air temperature -
-
-
-
-
The engine ECU calculates the EGR amount by adding main map value (intake air volume) and
auxiliary map value and directly drives the solenoid valve in the E-EGR to regulate the opening
extent of the EGR valve and sends the feedback to the potentiometer.
(1) Operating conditions
Intake air temperature: between -10 and 50℃
Atmospheric pressure: 0.92 bar or more
Engine coolant temperature: between 0 and 100°C
When there is no fault code related to EGR -
-
-
-
(2) Shut off conditions
Abrupt acceleration: with engine speed of 2600 rpm or more
When the engine is idling for more than 1 minute
Vehicle speed: 100 km/h or more
Engine torque: 380 Nm or more -
-
-
-
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14-32412-02
1. CAUTIONS
Standard pattern of soot accumulation ▶
(1) Abnormal Soot Accumulation (2) Normal Soot Combustion
Cautions to protect the catalyst filter ▶
Use the designated fuel only.
Observe the recommended service intervals of engine oil.
Check the engine oil level frequently and add if necessary.
Do not idle the vehicle unnecessarily.
Do not turn off the engine while the vehicle is running.
Do not shift the gear selector lever to neutral when going downhill.
Do not use improper engine oil or fuel additives.
Do not drive for a long time when the warning lamp is illuminated.
Make sure no flammable material, such as dry grass or tissue paper, contacts with the catalyst
filter while the vehicle is parked.
For the vehicles used in urban traffic, driving on the expressways for more than 1 hour at least
once per week is needed so that the PM inside CDPF isn't collected to one side only. -
-
-
-
-
-
-
-
-
-
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14-4
Overload of CDPF
(warning lamp blinking)Excessive overload of CDPF
(warning lamp illuminated)
(3) Warning Lamp Related to CDPF
CDPF regeneration process (warning lamp NOT illuminated) ▶
The CDPF system enters the regeneration mode
when the driving distance becomes approx. 600
to 1,200 km (may differ by the driving condition
and driving style). Then, the engine ECU
performs the CDPF regeneration operation.
However, the driver is not informed with this
operation by any engine warning lamp or
vehicle signal, so he/she may not detect this
operation. The control logic at the post-
injection dur-ing the regeneration process is to
increase the fuel injection volume and control
the intake air volume (by the throttle body) in
order to increase the temperature of the exhaust
gas. The driver may not feel any particular
difference from the vehicle.
If the CDPF cannot reach the regeneration
temperature due to low speed driving or other
reason during the regeneration process, the
soot is continuously accumulated in the CDPF.
When this condition continues and the CDPF is
overloaded with soot, the engine warning lamp
blinks to inform this situation to the driver.
In order to solve this problem, drive the vehicle
at a speed of approx. 80 km/h for 15 to 20
minutes to perform the CDPF regeneration
process.
If the engine warning lamp on the instrument
cluster blinks, the CDPF is overloaded. In this
case, perform the step 2. 1.
2.
3.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.
OFF
BlinkingIlluminating
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14-6
Differential Pressure Sensor
Calculates the amount of PM
collected by reading the pressure
difference between pre-CDPF and
post-CDPF.Engine ECU (D20DTR)
Post injection
Electric Throttle Body
Regulates the air intake
rate.CDPF
(DOC+DPF)Front EGT Sensor
Measures the combustion
temperature.
Rear EGT Sensor
Measures the CDPF
temperature.
2. COMPONENTS
For details, refer to section "Engine Control". *
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14-8
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
<0094008c0088009a009c0099008c008b0047008900a00047009b008f008c00470099008c008800990047009b008c00940097008c00990088009b009c0099008c0047009a008c0095009a00960099005500470070008d0047009b008f008c0047009b008c00
940097008c00990088009b009c0099008c00470090009a0047>less than 600℃, the amount of
post-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.
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14-92412-02
Rear temperature sensor
Measure the outlet
temperature of DOC.
This sensor is located at
the rear side of DOC and
monitors the overheating of
CDPF and post injection
volume.
Differential pressure sensor
Measures the difference between
inlet and outlet pressures of
CDPF.
If the difference is higher than the
specified value when collecting
the PM, this makes the post
injection for forced recycling of
PM.
Front temperature sensor
Measures the temperature of
exhaust gas.
This sensor is located at the rear
side of exhaust manifold and
monitors the temperature of
combusted gas to prevent the
exhaust system from overheating.
When the temperature gets
higher, this sensor cuts off the
fuel delivery and controls the EGR
to lower the temperature.
Engine ECU (D20DTR)
T-MAP sensorIntake air
mass
Measures
the
excessive
amount of
PM.
Injector (C31)
Controls the post injection.
Electric throttle body
Controls the intake air
mass.
HFM sensor
Wide band
oxygen
sensor
Boost
pressure/
temperature
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14-10
Collecting PM
→ Regeneration
The engine ECU detects the
amount of PM collected by
the information from the
temperature sensors and
differential pressure sensor.
When the soot is
accumulated, the engine ECU
performs post-injection to
increase the exhaust gas
temperature and burns the
collected PM at approx.
600°C.Oxidation (DOC)
When the exhaust gas enters
into the CDPF assembly, its
CO, HC and PM are reduced
by the redox reaction of the
DOC. The remaining PM is
filtered and collected in
CDPF, and the temperature of
the exhaust gas is increased
to between 450 and 500°C.
5. OPERATING PROCESS
[Configuration and principle of operation]
The exhaust gas
passed through the
exhaust manifold
enters into the CDPF
assembly (at approx
250℃).
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14-14
4) Fuel Injection During CDPF Regeneration
The injection method in D20DTR engine has three steps;
Pilot injection, Main injection, Post injection
Post injection ▶
<007b008f008c004700970096009a009b0047009000950091008c008a009b00900096009500470090009a0047009b008f008c0047009000950091008c008a009b0090009600950047009700990096008a008c009a009a00470088008d009b008c0099004700
940088009000950047009000950091008c008a009b00900096>n and consists of ‘After injection”,
“Post 1 injection” and “Post 2 injection”. All of post injections are to reduce the PM and harmful
exhaust gas. The post injection does not make the actual output. The post injection activates the
fuel by injecting the fuel to the incompletely combusted gas after primary combustion. Through
the process, the PM and smoke in the exhaust gas could be reduced. There are totally 7
injections as shown in the figure. However, all of 7 injections are not performed during driving
because it decreases the fuel economy. Totally 5 injections can be performed in one cycle.