SsangYong Rodius (2013 year). Service manual — part 80

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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.

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.

DPF(Diesel Particulate Filter)

▶

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 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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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.

-

-

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.