2012 SSANGYONG NEW REXTON Service Manual

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2.CDPF (EURO IV) SYSTEM CONTROL
1) General Description
As the soot is filtered in the CDPF, it is burnt and removed, and the CDPF is returned to the initial state to
collect the soot. Therefore, the burning procedures in the CDPF can be called as regeneration.
The CDPF assembly is integrated with DOC (at front side) and DPF (at rear side).
The DPF burns the soot with high-temperature exhaust gas (over
The rear exhaust gas
temperature sensor monitors the temperature of DPF section. If this temperature is below the
regeneration temperature, the ECU increases the post injection period to increase the fuel injection
amount, and consequently to increase the exhaust gas temperature.
Front exhaust gas temperature sensor
(Measuring temperature of exhaust gas in
exhaust manifold)
Rear exhaust gas temperature sensor
(Measuring temperature of exhaust gas
escaping DOC)
Normally, when the vehicle is driven for 600 ~ 1,200 km, the enough amount of soot to be burnt is
filtered and accumulated in the CDPF. The ECU increase the amount of post injection to increase
the tempeature of exhaust gas up to
so that the soot is burnt. The soot is burnt for
15 ~ 20 minutes. -

2) System Composition for Soot Combustion
When the engine is running in low load range, the temperature of exhaust gas is decreased as the
amount of fuel supplied is decreased. To burn the soot filtered in the CDPF, the control system should
be installed to check the operating range and increase the temperature of exhaust gas by controlling the
amount of fuel supplied and intake air.
Two temperature sensors and one differential pressure sensor monitor the CDPF's operating range.
According to these sensors' information, the throttle flap decreases the intake air entered to the throttle
body. Also, the fuel injection pattern is added to increase the temperature of exhaust gas for soot
combustion.
There are three fuel injection patterns (pilot injection, pre-injection and main injection). As the CDPF is
installed, the post injection pattern is added.
3) Post Injection and Air Mass Control
When the differential pressure sensor detects the pressure difference between the front and the rear
side of CDPF, the sensor sends signal indicating the soot is acumulated and the post injection is
performed to raise the temperature of exhaust gas. The amount of fuel injected is determined according
to the temperature of exhaust gas detected by the rear temperature sensor. If the temperature is below
the amount of fuel injected is increased to raise the temperature. If the temperature is over
the amount of fuel injected is decreased or not controlled.
When the engine is running in low load range, the amount of post injection and the amount of intake ai
r
are controlled. It is to raise the temperature by increasing the amount of fuel while decreasing the
amount of intake air.

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Throttle bodies by engine type
The throttle valve is controlled by electric signals sent from the engine ECU for optimal fuel
injection volume, engine load and effective combustion of EGR gas according to the Euro 4
regulations. It has following functions by the engine type. -

3. SOOT FILTERING AND BURNING PROCEDURES
1) Operating Procedures of CDPF
The most efficient and practical technology for now is adopted to the diesel particulate filter (DPF).
This system collects the soot from the diesel engine to the filter and burns the soot so that over than 95%
of soot can be removed from the exhaust gas. However, the durability and the cost of additional system
remainas problems.
Firstly, the exhaust gas is passed through the DOC and its temperature is increased as it is oxidized.
The ECU detects the temperature change with two temperature sensors. The CO, HC and partial
particulate material are removed from the exhaust gas (this procedures are the sames as the ones fo
r
the conventional DOC and no sensor is required).
After the exhaust gas is passed through the DOC and oxidized, most of the harmful material is removed
from the exhaust gas. However, to meet the environmental regulations in the future, the soot is filtered
and burnt again in DPF to decrease the particulate material further.
The filtered soot is burned whenever the vehicle is driven for 600 ~ 1200 km. The driving distance
can be differed depending on the
driving conditions. The soot is burnt for 15 ~ 20
minutes. -Exhaust
gas
Rear exhaust gas temperature
sensor(Measuring temperature of
exhaust gas escaping DOC)

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Front temperature sensor
(Measuring the temperature of
exhaust gas passedthrough
exhaust manifold)Rear temperature sensor
(Measuring the temperature of exhaust
gas passed through DOC)
Differrential pressure sensor
(Front pressure port)Differrential pressure sensor
(Rear pressure port)
The engine ECU detects the
amount of particulate material
colected by the information
from temperature sensors
and differential pressure
snesor. When the soot is
accumulated, the pressure
difference be-tween the front
and the rear side occurs.
Then, the engineECU
performs the post injec-tion to
raise the exhaust gas
temperature and burn the
collected soot at approx. The exhaust gas enters
intoCDPF assembly after
passing through the exhaust
manifold. (Normal
temperature of ex-haust gas: When the exhaust gas
enters into the CDPF
assembly, its CO, HC and
particulate mate-rial are
reduced as it is oxi-dized in
DOC. The remaining
particulate material is
filtered and collected in
DPF and the temperature
of exhaust gas is increased

2) Fuel Injection During CDPF Regeneration
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 in-formed with this operation by an
y
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 tem-perature of the
exhaust gas. The driver may not feel any particular difference
from the vehicle.
No illumination

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Overload of CDPF (warning lamp blinking)
Excessive overload of CDPF (warning lamp illuminated)
If the CDPF cannot reach the regeneration tem-
perature due to low speed driving or other reason during
the regeneration process, the soot is con-tinuously
accumulated in the CDPF. When this condition continues
and the CDPF is overloaded with soot, the engine
warning lamp blinks to in-form 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 clus-te
r
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 accumu-lated in the
CDPF cannot be burnt as the CDPF cannot reach the
regeneration temperature. Then, an excessive amount o
f
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 en-gine 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.
Actually, the DTC for the CDPF is generated more often by the component related to the CDPF system,
such as the differential pressure sensor, than by excessive soot in the CDPF. Blinking
Illumination

Throttle Body
Engine compartment
(RH)
4. COMPONENTS OF CDPF SYSTEM
1) Mounting Condition and Location
Differential Pressure Sensor
Rear exhaust gas
temperature sensor
Front Exhaust Gas
Temperature Sensor
Front exhaust gas
temperature sensor
Rear pressure
port
CDPF assemblyFront pressure portDifferential
pressure
sensor