SsangYong Korando III (2010 year). Manual - part 68

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1. OVERVIEW

The DOC (Diesel Oxidation Catalyst) generates CO2 and H2O which are harmless through the 

oxidation process of CO and HC. And the DPF (Diesel Particulate Filter) collects PM (Particle Matter) 

and is regenerated to reduce the quantity of particulates, HC and CO. But there is a limitation in reducing 

the emission of exhaust gas for each system, so the CDPF which combines these two system is 

applied.

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Engine ECU (D20DTF)

Post-injection

Differential 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

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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.

If the temperature exceeds 600℃, the life of CDPF can be reduced. So the amount of fuel 

post-injection is decreased.
If the temperature drops under 600℃, the rate of regeneration can be decreased. So the 

amount of fuel post-injection is increased.

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-

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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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 
sensor. If the temperature is 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.

4. POST-INJECTION AND AIR MASS CONTROL