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SsangYong: Engine Euro 4. Manual - part 26

CHANGED BY

EFFECTIVE DATE

AFFECTED VIN

2411

EXHAUST SYSTEM

D27DTP/D27DT (EU4) SM - 2006.08

D27DTP/D27DT (EU4)

ENGINE

FUEL

AKE

EXHAUST

PRE-HEA

TING

LUB

COOLING

SWITCHABLE

ECU

DIAGNOSIS

The two temperature sensors are installed in the front and the rear side of the CDPF to
measure the temperature of exhaust gas passed through the exhaust manifold and the
temperature of exhaust gas passed through DOC. As the exhaust gas is passed through
DOC, its temperature is increased as it is oxidized.

When the CDPF is in the burning range according to the signal from the differential pressure
sensor, the ECU adds up the post injection pattern to raise the exhaust gas temperature.
When the engine is running in low load range, the temperature of exhaust gas is low. Therefore,
the throttle flap is used to decreased the amount of intake air so that the the exhaust gas’s
temperature is increased. The ECU decreases or stops the post injection when the tempera-
ture detected from the rear temperature sensor is over 600

C. The ECU increases the amount

of post injection when the temperature is below 600

C to control the temerature in CDPF.

7. COMPONENTS OF CDPF

CDPF Temperature sensor

Overview of CDPF Temperature Sensor

Temperature Sensor’s Connecting Port and connector

Output signal

Ground

Mounting location of temperature sensor in CDPF

Differrential pressure

sensor rear port

Differrential pressure

sensor front port

Flexible cable

(Copper wires coated with nickel)

Nut connection (M14*1.5)

Housing

Temperature sensor housing’s front side is 35 mm long,
while its rear side is 50 mm long.

Tightening torque when installing:
45 Nm ± 4.5 Nm

Rear temperature

sensor

Front temperature

sensor

Temperature sensing oart
(24 holes with the diameter of 2.2 mm)

CHANGED BY

EFFECTIVE DATE

AFFECTED VIN

2411

EXHAUST SYSTEM

D27DTP/D27DT (EU4) SM - 2006.08

D27DTP/D27DT (EU4)

The temperature sensor is coated with thin platinum and has 24 holes with its diameter of 2.2 mm. As the tempera-
ture in CDPF increases, the resistance also increases and the temperature sensor sends the changed voltage value
to ECU.

+Signal

(Output voltage):

Grey

-Ground

(Output voltage):

White

Connector

Temperature

sensor

Resistance by Temperature Detected By Temperature Sensor

Output signal

(voltage)

Ground

CDPF temperature (°C)

Resistance(

Ω)

Output voltage(V)

-40

-20

100

150

200

250

300

350

400

450

500

600

700

800

900

1000

170.2

185.6

201.0

220.1

239.0

276.4

313.2

349.5

385.1

420.2

454.7

488.6

521.9

554.6

618.3

679.7

738.7

795.4

849.7

0.727

0.783

0.837

0.902

0.964

1.083

1.193

1.295

1.390

1.479

1.563

1.641

1.715

1.784

1.910

2.023

2.124

2.215

2.297

CHANGED BY

EFFECTIVE DATE

AFFECTED VIN

2411

EXHAUST SYSTEM

D27DTP/D27DT (EU4) SM - 2006.08

D27DTP/D27DT (EU4)

ENGINE

FUEL

AKE

EXHAUST

PRE-HEA

TING

LUB

COOLING

SWITCHABLE

ECU

DIAGNOSIS

Differrential Pressure Sensor

The differential pressure sensor is connected to CDPF
through two ports.

It can be found behind the front left tire (on the frame in
front of the coil spring).

This sensor detects the pressure difference between the
front and the rear side of CDPF. When the soot is col-
lected in CDPF, the pressure difference is increased
and this difference, as a signal, is sent to ECU to per-
form the post injection.

The differential pressure sensor monitors the pressure
of the opening of DOC and the end of DPF. When the
soot is collected as the exhaust gas is passed through
CDPF, the sensor sends the combustion timing to the
ECU. Then, the ECU performs the post injection to in-
crease the temperature in CDPF up to 600°C. At this
time, the temperature is monitored by rear temperature
sensor. According to the temperature monitored, the
amount of post injection is increased or decreased, or
the post injection is ceased.

Sensing port for differential pressure sensor

Sensor signal

Sensor ground

Sensor voltage (5V)

Differrential

pressure sensor

Mounting Location and Overview

Differrential pressure sensor

Front pressure port

Connecting Port and Connector

- Measured resistance range:

0 ~ 100 Kpa

- Supply voltage: 50.25V
- Operating temperature range:

-40 ~ 125°C

- Sensor output signal: 0.5 ~ 4.5V
- Supply current: 20 mA

Specifications

• When the engine is running in high load/speed

range, the temperature of exhaust gas passed
through DOC can be over 600°C. If it happens, the
collected soot is burnt without post injection.

• The filtered soot is burnt normally after the vehicle

is driven for 300 ~ 500 km.

NOTICE

Rear pressure port

CHANGED BY

EFFECTIVE DATE

AFFECTED VIN

2411

EXHAUST SYSTEM

D27DTP/D27DT (EU4) SM - 2006.08

D27DTP/D27DT (EU4)

The differential pressure sensor sends the output voltage (0.5 ~ 4.5V) to ECU depending on the CDPF's pressure
difference between front and rear sides.

The front and rear pressure ports installed on CDPF are not sensors, but the connecting ports to send the pressure
to the differential pressure sensor.

The front and rear connecting ports send the pressure values of “before CDPF” and “after CDPF” to differential
pressure sensor. Then, the differential pressure sensor compares these values and sends the pressure difference
value to ECU.

As the soot is collected, the pressure difference gets greater. When the soot mass filtered exceeds the limit
(normally 28 g) and the pressure difference occurred from this is sent to ECU, ECU starts the burning process in
CDPF. When the CDPF is in operating range, the post injection is performed if the engine is running at idle speed or
in low-mid speed range. When the engine is running at idle speed, the flap in the throttle body is controlled to reduce
the intake air.

As shown on the graph above, the smaller the pressure difference is, the greater the output voltage (signal) from the
differential pressure sensor. When the pressure difference is over 1 bar, the sensor sends 4.5 V as output voltage to ECU.

0.5bar

1bar

0.5

4.5

Pressure difference in CDPF (

ΔΔΔΔΔP sensor)

Sensor signal voltage(V)

These pressure ports are installed in the same manner as temperature sensors. However, they are not the sensors
but just for transmitting the pressure in CDPF to the differential pressure sensor.

Pressure Difference and Output Voltage

Location of Pressure Measuring Ports

Rear Port (CDPF Rear)

Front Port (CDPF Front)

Tightening torque: 45 Nm ± 4.5 Nm

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