Page 193 of 751
14-92412-02
Differential pressure
sensor
Calculates the amount of
PM collected by reading the
pressure difference between
before and after the CDPF.Engine ECU
DCM 3.7
Post-injectionThrottle
valve
Regulates the rate of air
intake.
CDPF
DOC+DPFFront temperature
sensor
Protects the turbocharger.Rear temperature sensor
Measures the temperature
of fuel combustion.
2. COMPONENT
For details, refer to section "Engine Control". *
Page 194 of 751

14-10
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.
<0070008d0047009b008f008c0047009b008c00940097008c00990088009b009c0099008c0047008c009f008a008c008c008b009a0047005d005700570b4500530047009b008f008c004700930090008d008c00470096008d0047006a006b0077006d004700
8a0088009500470089008c00470099008c008b009c008a008c>d. So the amount of fuel
post-injection is decreased.
<0070008d0047009b008f008c0047009b008c00940097008c00990088009b009c0099008c0047008b009900960097009a0047009c0095008b008c00990047005d005700570b4500530047009b008f008c004700990088009b008c00470096008d0047009900
8c008e008c0095008c00990088009b0090009600950047008a>an 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.
Page 195 of 751

14-112412-02
4. POST-INJECTION AND AIR MASS CONTROL
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
<009a008c0095009a00960099005500470070008d0047009b008f008c0047009b008c00940097008c00990088009b009c0099008c00470090009a00470093008c009a009a0047009b008f008800950047005d005700570b4500530047009b008f008c004700
8800940096009c0095009b00470096008d004700970096009a>t-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.
Page 196 of 751

14-12
Front temperature sensor
Measures the temperature of
exhaust gas.
This sensor is located at the rear
side of exhaust manifold and
monitors the temperature of
combusted gas to prevent the
exhaust system from overheating.
When the temperature gets higher,
this sensor cuts off the fuel delivery
and controls the EGR to lower the
temperature.Rear temperature sensor
Measure the outlet
temperature of DOC.
This sensor is located at the
rear side of DOC and
monitors the overheating of
CDPF and post injection
volume.
Engine ECU (D20DTR)
Differential pressure sensor
Measures the difference between
inlet and outlet pressures of CDPF.
If the difference is higher than the
specified value when collecting the
PM, this makes the post injection for
forced recycling of PM.
T-MAP sensorIntake air
mass
Measures
the
excessive
amount of
PM.
Boos
t
pressure
/
temperature
Injector (C31)
Controls the post injection.
Electric throttle body
Controls the intake air mass.
HFM sensor
Wide band
oxygen senso
r
Page 197 of 751
14-132412-02
Collecting PM
→ Regeneration
The engine ECU detects the
amount of PM collected by the
information from the
temperature sensors and
differential pressure sensor.
When the soot is accumulated,
the engine ECU performs post-
injection to increase the
exhaust gas temperature and
burns the collected PM at
approx. 600°C.Oxidation (DOC)
When the exhaust gas enters
into the CDPF assembly, its
CO, HC and PM are reduced
by the redox reaction of the
DOC. The remaining PM is
filtered and collected in CDPF,
and the temperature of the
exhaust gas is increased to
between 450 and 500°C.
5. OPERATING PROCESS
[Configuration and principle of operation]
The exhaust gas
passed through the
exhaust manifold
enters into the CDPF
assembly (at approx
250℃).
Page 198 of 751

14-14
1) Oxidation of DOC
The DOC oxidizes HC and CO of the exhaust gas in the two-way catalytic converter at 180℃ or
<009400960099008c0053004700880095008b00470097008c0099008d009600990094009a00470089008c009a009b00470088009b0047009b008f008c0047009b008c00940097008c00990088009b009c0099008c00470089008c009b009e008c008c009500
47005b00570057004700880095008b0047005c005700570b45>. The front EGT sensor
detects whether the DOC can burn (oxidize) the post-injected fuel or not, and sends the signal to the
<006c006a007c0047009b009600470094008800900095009b0088009000950047009b008f008c0047006b0076006a004700960097008c00990088009b00900095008e0047009b008c00940097008c00990088009b009c0099008c00470089008c009b009e00
8c008c00950047005a00570057004700880095008b0047005c>00℃. The DOC reduces CO
and HC of the exhaust gas by redox reaction and also reduces small amount of PM.
<0058005500470076009f00a0008e008c009500470088008b008f008c0099008c009a0047009b00960047009b008f008c0047008a0088009b0088009300a0009a009b004700940088009b008c0099009000880093009a006100470073008c009a009a004700
9b008f0088009500470058005f00570b45>
2. CO and HC are oxidized by the catalyst materials: More than 180℃
Page 199 of 751

14-152412-02
2) Collecting PM of DPF
There is a filter installed in the DPF and the PM filtered by this filter is burned (regeneration) when the
temperature of exhaust gas is increased due to post-injection. The filter has a honeycomb-like structure
to capture the particulate matter and the inlet and outlet of each channel are closed alternatively. Once
the exhaust gas enters to the inlet of a channel, it is released from the outlet of the adjacent channel
through the porous wall because of the closed outlet of the first channel, and the PM is collected in the
first channel.
[Collecting PM of CDPF]
Normally, when the driving distance becomes approx. 600 to 1,200 km, enough amount of soot to
be burned is filtered and accumulated in the CDPF. The ECU increases the amount of fuel post-
<009000950091008c008a009b0090009600950047009b0096004700900095008a0099008c0088009a008c0047009b008f008c0047009b008c00940097008c00990088009b009c0099008c00470096008d0047009b008f008c0047008c009f008f0088009c00
9a009b0047008e0088009a0047009c00970047009b00960047>600°C, so that the soot is
burned. The soot is burned for 15 to 20 minutes (may differ by conditions).
Page 200 of 751
14-16
3) PM Regeneration of DPF
The differential pressure sensor installed in the DPF measures the pressure values of inlet and outlet of
CDPF. And the amount of the PM collected in the filter is calculated based on the exhaust temperature,
intake air mass flow, booster pressure, etc.
The regeneration is started when the amount of the collected PM is 28 g or more.
<007b008f008c0047006c006a007c0047008a00960094009400880095008b009a004700970096009a009b0054009000950091008c008a009b0090009600950047009b0096004700900095008a0099008c0088009a008c0047009b008f008c0047009b008c00
940097008c00990088009b009c0099008c00470096008d0047>CDPF to 600℃.
When the amount of the collected PM is not enough: The DPF works as a filter. 1.
When enough amount of PM is collected: The ECU commands post-injection and increase the exhaust
gas temperature to start regeneration. 2.