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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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13-51793-00
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
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.
See the section "Engine control" for E-EGR
valve control logic.
EGR cooler
EGR bypass
For details, see the section "Engine control". *
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13-8
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 -
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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 -
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(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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14-4
2. CAUTIONS
1) Standard pattern of soot accumulation
Abnormal Soot Accumulation ▶
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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14-52412-02
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.
Overload of CDPF (warning lamp blinking)
2) Warning Lamp Related to CDPF
CDPF regeneration process (warning lamp NOT illuminated) ▶
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.
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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.
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14-72412-02
1. OVERVIEW
The low emission vehicle is being sold increasingly in the market as a countermeasure for complying
with the environment regulations such as a special act on Seoul metropolitan air quality improvement
and for reducing the PM (Particulate Material) from the diesel-powered vehicle. For the CDPF system,
the DOC (two-way catalytic converter or catalytic combustion system) fitted to the conventional diesel
engine has the high purification rate for HC or CO but not have a high reduction rate for the PM. For this
reason, a necessity has been raised in order to consider a countermeasure to reduce the PM since the
existing DOC can't meet the regulation, which is getting tighter.
This results in a development of the CDPF (Catalyst & Diesel Particulate Filter) that is combination of the
existing DOC (Diesel Oxydation Catalyst) and DPF (Diesel Particulate Filter). While the DOC converts
the CO and HC into the CO2 and H2O - unharmful to human body - using a oxidation reaction, the DPF
collects the PF (Particulate Material) for regeneration of it. However, each of these devices can only
reduce a part of the exhaust gas. This evoked the necessity of the CDPF with both features. The DOC
capacity is more on the manual transmission than the automatic transmission.
DPF(Diesel Particulate Filter) ▶DOC(Diesel Oxidation Catalyst) ▶
It is called as a oxidation catalyst, which purifies CO and HC in exhaust gas. The three-way catalyst is
used for the gasoline vehicle. But, the diesel engine oxidates CO and HC excepting NOx into H2O and
CO2 in order to purify the exhaust gas since the exhaust gas has a rich oxygen at all times.
It consists of mainly the aluminum and titanium and there is a porous thin film, which emits the exhaust
gas but does not emit the PM in it. It emits the exhaust gas generated during combustion and filters the
PM which is a byproduct of combustion to burn it when a certain amount of it is collected in the filter.
When a certain amount of the PM builds up, exposure to high exhaust gas causes carbon, the
fundamental ingredient in PM, to burn and release into the atmosphere in form of CO2.
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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". *