engine SSANGYONG RODIUS 2012 Service Manual

14-8
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
<0094008c0088009a009c0099008c008b0047008900a00047009b008f008c00470099008c008800990047009b008c00940097008c00990088009b009c0099008c0047009a008c0095009a00960099005500470070008d0047009b008f008c0047009b008c00
940097008c00990088009b009c0099008c00470090009a0047>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.

14-92412-02
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.
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.
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.
Engine ECU (D20DTR)
T-MAP sensorIntake air
mass
Measures
the
excessive
amount of
PM.
Injector (C31)
Controls the post injection.
Electric throttle body
Controls the intake air
mass.
HFM sensor
Wide band
oxygen
sensor
Boost
pressure/
temperature

14-10
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℃).

14-14
4) Fuel Injection During CDPF Regeneration
The injection method in D20DTR engine has three steps;
Pilot injection, Main injection, Post injection
Post injection ▶
<007b008f008c004700970096009a009b0047009000950091008c008a009b00900096009500470090009a0047009b008f008c0047009000950091008c008a009b0090009600950047009700990096008a008c009a009a00470088008d009b008c0099004700
940088009000950047009000950091008c008a009b00900096>n and consists of ‘After injection”,
“Post 1 injection” and “Post 2 injection”. All of post injections are to reduce the PM and harmful
exhaust gas. The post injection does not make the actual output. The post injection activates the
fuel by injecting the fuel to the incompletely combusted gas after primary combustion. Through
the process, the PM and smoke in the exhaust gas could be reduced. There are totally 7
injections as shown in the figure. However, all of 7 injections are not performed during driving
because it decreases the fuel economy. Totally 5 injections can be performed in one cycle.

14-16
7. CAUTIONS
1) Designated Engine Oil for CDPF (Low Ash Oil)
Need to use the designated engine oil for CDPF 1.
The smoke from the vehicle may generate the particle material in the ambient air. CDPF is
the device to reduce the smoke by collecting and recycling it. To ensure the performance
of CDPF, the designated engine oil should be used.
The smoke including combusted sulfur in fuel cannot be recycled in CDPF. This smoke
generates the ash, resulting in clogging the filter. -
-
Advantages when using the designated engine oil for CDPF 2.
Reduces the amount of ash
Improves the fuel economy and reduces the CO2
Increases the life span of engine oil
Available for all engines (diesel and gasoline) -
-
-
-
Problems when using non-designated engine oil for CDPF 3.
Decreases the life span of engine oil due to accumulated ash in DPF (around 30%)
Decreases the fuel economy due to friction resistance, exhaust gas resistance and
frequent recycling process of DPF -
-
The fuel containing high sulfur may cause the same problems.

15-30000-00
1. ENGINE DATA LIST
Data Unit Value
Coolant temperature℃ 130℃~-40℃
Intake air temperature℃ -40 to 130℃ (varies by ambient air
temperature or engine mode)
Idle speed rpm 700 ± 50 (P/N), 600 ± (D)
Engine load % 18~25%
Mass air flow kg/h 16 to 25 kg/h
Throttle position angle°TA 0° (Full Open) to 78° (Close)
Engine torque Nm varies by engine conditions
Injection time ms 3 to 5ms
Battery voltage V 13.5 V to 14.1 V
Accelerator pedal position 1 V 0.4. to 4.8V
Accelerator pedal position 2 V 0.2 to 2.4 V
Throttle position 1 V 0.3 to 4.6 V
Throttle position 2 V 0.3 to 4.6 V
Oxygen sensor V 0 to 5 V
A/C compressor switch
1=ON / 0=OFF -
Full load 1=ON / 0=OFF -
Gear selection (A/T) 1=ON / 0=OFF -
Knocking control 1=ON / 0=OFF -
Brake switch 1=ON / 0=OFF -
Cruise control 1=ON / 0=OFF -

15-110000-00
2) ECU Control
(1) Function
a. ECU Function
ECU receives and analyzes signals from various sensors and then modifies those signals into
permissible voltage levels and analyzes to control respective actuators.
ECU microprocessor calculates injection period and injection timing proper for engine piston speed and
crankshaft angle based on input data and stored specific map to control the engine power and emission
gas.
Output signal of the ECU microprocessor drives pressure control valve to control the rail pressure and
activates injector solenoid valve to control the fuel injection period and injection timing; so controls
various actuators in response to engine changes. Auxiliary function of ECU has adopted to reduce
emission gas, improve fuel economy and enhance safety, comforts and conveniences. For example,
there are EGR, booster pressure control, autocruise (export only) and immobilizer and adopted CAN
communication to exchange data among electrical systems (automatic T/M and brake system) in the
vehicle fluently. And Scanner can be used to diagnose vehicle status and defectives.
<00760097008c00990088009b00900095008e0047009b008c00940097008c00990088009b009c0099008c0047009900880095008e008c00470096008d0047006c006a007c00470090009a0047009500960099009400880093009300a000470054005b005700
47009b009600470052005f005c00b6006a004700880095008b> protected from factors like oil,
water and electromagnetism and there should be no mechanical shocks.
To control the fuel volume precisely under repeated injections, high current should be applied instantly
so there is injector drive circuit in the ECU to generate necessary current during injector drive stages.
Current control circuit divides current applying time (injection time) into full-in-current-phase and hold-
current-phase and then the injectors should work very correctly under every working condition.
b. Control Function
Controls by operating stages
To make optimum combustion under every operating stage, ECU should calculate proper injection
volume in each stage by considering various factors.
Starting injection volume control
During initial starting, injecting fuel volume will be calculated by function of temperature and engine
cranking speed. Starting injection continues from when the ignition switch is turned to ignition
position to till the engine reaches to allowable minimum speed.
Driving mode control
If the vehicle runs normally, fuel injection volume will be calculated by accelerator pedal travel and
engine rpm and the drive map will be used to match the drivers inputs with optimum engine power. -
-
-

15-12
(2) Fuel injection control
a. Multi injection
Fuel injection process consists of 3 steps: Main Injection, Pilot Injection, Post Injection
This is the injection before main injection. This consists of 1st and 2nd pilot injection, and Pre-injection.
The steps are normally used to control the NOx, noise, idle stability and engine vibration. Inject a small
amount of fuel before main injection prevents the instant high combustion temperature. It reduces the
NOx and decreases the engine noise and vibration. The main injection produces the actual output. The
vehicle output is based on the main injection. The post injection is the injection process after main
injection and consists of ‘After injection”, “Post 1 injection” and “Post 2 injection”. All of post
injections are to reduce the PM and harmful exhaust gas. The post injection does not make the actual
output. The post injection activates the fuel by injecting the fuel to the incompletely combusted gas after
primary combustion. Through the process, the PM and smoke in the exhaust gas could be reduced.
There are totally 7 injections as shown in the figure. However, all of 7 injections are not performed during
driving because it decreases the fuel economy. Totally 5 injections can be performed in one cycle.
InjectionFunction
MainProduces engine power
Pilot 1Reduces PM by injecting before
main injection.AfterPM control
Pilot 2Reduces NOx and noise by
shortening main injection delay
due to flammability Post 1Reduces PM by enabling fuel
activation.
PreControls NOx emission level,
Combustion noise and
Stable idle Post 2Activates CDPF by increasing
exhaust gas temperature and
supplying reduction material

15-130000-00
b. Pilot Injection
Injection before main injection. Consists of 1st and 2nd pilot injection, and Pre-injection
Inject a small amount of fuel before main injection to make the combustion smooth. Also, called as
preliminary injection or ignition injection. This helps to reduce Nox, engine noise and vibration, and to
stabilize the idling.
The injected fuel volume is changed and stopped according to the coolant temperature and intake air
volume.
Pilot injection is much earlier than main injection due to higher engine rpm
Too small injection volume (insufficient injection pressure, insufficient fuel injection volume in main
injection, engine braking)
System failure (fuel system, engine control system) -
-
-
Pilot injection
Main injection
Combustion pressure with pilot injection
Combustion pressure without pilot injection 1.
2.
1a.
2b. Stop conditions
Combustion pressure characteristic curve for pilot injection ▶

15-14
c. Main Injection
The power of the vehicle is determined by the main fuel injection volume.
Main injection calculates the fuel volume based on pilot injection. The calculation uses the value for
accelerator pedal position, engine rpm, coolant temperature, intake air temperature, boost pressure,
boost temperature and atmospheric pressure etc.
d. Post Injection
Injection after main injection. Consists of After injection, Post 1, Post 2 injection.
Post injection reduces PM and smoke from exhaust gas. No actual output is generated during these
injections, instead, fuel is injected to the unburned gas after main injection to enable fuel activation.