2012 SSANGYONG NEW REXTON sensor

2. CDPF(EURO IV) SYSTEM
The CDPF system is only installed to the D27DT engine, and the major changes comparing to the
previous D27DT engine is as follows:
CDPF (Catalyst & Diesel Particulate Filter) and sensors
Under air cleaner in righ
side of engine
compartment
As the soot is filtered in the CDPF, the pressure between the front side and the rear side of the
filter is different from each other. If the amount of soot is over 28 g, the soot is burnt in the
CDPF. The combustion is determined depending on the pressure difference, temperature of
exhaust gas and EGR ratio. According to these, the soot filtered by post injection of injector is
burnt at
CDPF Exhaust Gas Temperature Sensor
The two temperature
sensors inside the CDPF
are installed in exhaust
manifold (front exhaust
gas temperature sensor)
and in DOC (rear exhaust
gas temperature sensor),
and perform the following
functions.Front Exhaust Gas Temperatur
e
Sensor:Rear Exhaust Gas
Temperature Sensor:
Measures the exhaust gas
temperature of the exhaust manifold.
As it is installed in front of the VGT
turbocharger, it also monitors the
exhaust gas temperature coming to
the turbocharger. If the temperature
of the exhaust gas flowing to the
turbocharger is higher than the
specification, the engine lowers the
exhaust gas temperature.Measures the increased
exhaust gas temperature
after the oxidation process
of DOC. If the temperature
injection amount is
increased to increase the
temperature.
Front exhaust gas
temperature sensor

1725-12
Throttle Body
CDPF system controls the amount of intake air by
controlling the electronic throttle body. The electronic
throttle body has the following main functions.
CDPF control - added a function that increases the
exhaust gas temperature by closing the throttle valve
flap to minimize the intake air amount by the fuel
injection amount during the CDPF regeneration range
with the low engine load range.
ON/OFF control - prevents the engine from turning off
with vibration and noise by closing the throttle body flap
to block the intake air when the engine is stopped.
Duty control - controls the valve inside the throttle body
to burn more EGR gas in the EGR valve operating range.
VGT Turbocharger and Front Exhaust Gas Temperature Sensor
Front exhaust gas
temperature sensorTurbocharger may become weaker if high
temperature exhaust gas passes through the
turbocharger for DPF regeneration process.
The front exhaust gas temperature sensor monitors
the temperature of the exhaust gas that flows into
the turbocharger.
If the temperature of the exhaust gas that passes
through the exhaust manifold is higher than the
specification, the ECU decreases the fuel injection
amount and increases the EGR gas intake amount
to decrease the exhaust gas temperature.

1725-12
2. CDPF (EURO IV) SYSTEM CONTROL
1) Combustion Temperature and Procedures
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. -

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 air are controlled. It is to raise the temperature by increasing the amount of fuel while
decreasing the amount of intake air.
2) Sytem 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. 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 remain as 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 for 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.
Rear exhaust gas temperature sensor
(Measuring temperature of exhaust gas
escaping DOC)
The filtered soot is burned whenever the vehicle is driven for 600 ~ 1200 km. The driving
distance can be differed depending on the vehicle's driving conditions. The soot is burnt
for 15 ~ 20 minutes. -

1725-12
Front temperature sensor
(Measuring the temperature of
exhaust gas passed through
exhaust manifold)
Differrential pressure sensor (Front
pressure port) Differrential pressure sensor (Rear
pressure port) Rear temperature sensor
(Measuring the temperature of exhaust gas
passed through DOC)
The exhaust gas enters
into CDPF assembly after
passing through the
exhaust manifold.
(Normal temperature of
exhaust gas: approx. 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 between the
front and the rear side
occurs. Then, the engine
ECU performs the post
injection to raise the
exhaust gas temperature
and burn the collected soot
at approx. When the exhaust gas
enters into the CDP
F
assembly, its CO, HC and
particulate material are
reduced as it is oxidized in
DOC. The remaining
particulate material is
filtered and collected in
DPF and the temperature
of exhaust gas is
increased to approx. 450
~

1725-12
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 burnt 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 overload
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.
Actually, the DTC for the CDPF is generated more often by the component related to the CDP
F
system, such as the differential pressure sensor, than by excessive soot in the CDPF.
Illuminating
Blinking

4. COMPONENTS OF CDPF SYSTEM
Engine compartment
(RH)
Differential Pressure Sensor
Front Exhaust Gas
Temperature SensorThrottle Body
Front exhaust gas
temperature sensor