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Diff. pres. sensor: Measure
pressure between front
side and rear side of CDPF
ECU (DCM 3.7)
Injector: Control post
injection
D. Operation process
When the differential pressure sensor detects the pressure difference between the front and the rear
side of CDPF, the sensor sends signal indicating the soot is accumulated and the post injection is
performed to raise the temperature of exhaust gas. The amount of fuel injected is determined according
to the temperature of exhaust gas detected by the rear temperature sensor. If the temperature is below
low load range, the amount of post injection and the amount of intake air are controlled. It is to raise the
temperature by increasing the amount of fuel while decreasing the amount of intake air.
Front EGT sensor:
Measure DOC temp.
Rear EGT sensor: Measure
DPF temp.
Electronic throttle
body: Control intake
air mass
T-MAP sensor
Intake air
mass
Exceed PM
limitBooster
pressure/
temperaturePost injection
Control intake
air mass
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0000-00
E. Cautions
Use only specified Engine Oil (approved by MB Sheet 229.51) for CDPF. -
Use only specified engine oil (Low Ash Oil)
The vehicle equipped with CDPF should use specific engine oil to improve the engine performance
and fuel economy, and ensure the service life of CDPF. -
Issue with normal engine oil
Sulfur, one of the contents of engine oil is burned and generates soot that is not regenerated by the
DPF. This remains on the filter as ashes and keeps accumulating. Eventually, this ashes will block
the filter. -
Benefit for specified engine oil
Minimized the sulfur content of engine oil which reduces the service life.
Improved fuel economy and emission level of CO2 with high performance and low viscosity.
Increased service life of engine oil with high resistance to temperature. -
-
-
Problems when using unspecified engine oil
The service life of filter may be reduced by 30% or more by the ashes accumulated on the filter.
The fuel economy may be reduced because of engine rolling resistance, frequent regeneration of
DPF. -
-
These problems are also caused by oil with high sulfur content, such as tax exemption oil and
heating oil, etc. *
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0000-00
3) Guidelines on Engine Service
To prevent personal injuries and vehicle damages that can be caused by mistakes during engine
and unit inspection/repair and to secure optimum engine performance and safety after service
works, basic cautions and service work guidelines that can be easily forgotten during engine
service works are described in.
Cautions before service works
For safe and correct works, you must observe the working procedures and instructions in this
manual. And, use the designated tools as follow:
Engine stand / Heavy duty engine jack
To prevent the engine from starting abruptly, do not allow anybody to get in the vehicle while
servicing in engine compartment.
Before work on engine and electrical equipment, be sure to disconnect battery negative (-)
terminal.
Before service works, be sure to prepare the works by cleaning and aligning work areas.
Do not allow the foreign material get into the fuel injection system.
When removing the engine, use only the safety hook on engine and engine hanger. Do not
support the bottom of oil pan with a jack. -
-
-
-
-
Completely drain the engine oil, coolant and fuel from engine before removal.
Before disassembling/assembling the engine components, carefully read the working
procedures in this manual.
Make sure to keep the specified tightening torques during installation.
Clean and properly lubricate the parts before reassembly.
Carefully check that there is not any interference while servicing. -
-
-
-
-
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Do not allow the fluid and engine oil to make contact with the body paintwork and hoses.
If work on the fluid system such as fuel and oil, working area should be well ventilated and
smoking should be prohibited.
Gasket or seal on the fuel/lubrication system should be replaced with new ones and bolts and
nuts should be tightened as specified.
After removal/installation works, be sure to check whether there is leak on the connecting
section. -
-
-
-
If fine dust or foreign material enters into DI engine's fuel system, there can be serious
damages between HP pump and injectors. So, be sure to cover removed fuel system
components with cap and protect removed parts not to be contaminated with dirt. (Refer to
cleanness in this manual while working on DI engine fuel system)
When working on the fuel line between priming pump and injector (including return line),
always plug the openings with caps to prevent foreign materials or dust from entering to the
openings and connections.
The HP fuel supply pipe (HP pump to fuel rail) and HP fuel pipe (Fuel rail to injector) should
be replaced with new ones when removed. 1.
2.
3.
Electric devices should be handled more carefully.
Currently, the engine has a lot of electric devices. There could be poor engine performance,
incomplete combustion and other abnormal symptoms due to short circuit or poor contact.
Before work on engine and electrical equipment, be sure to disconnect battery negative (-)
terminal.
When replacing the electric device, use only genuine part and check the conditions of
connections and grounds. Loosened connection or ground makes cause a fire and personal
injury. -
-
Page 514 of 600
Engine Compartment Layout
Engine assembly
Engine oil dipstick
Vacuum pump
Oil filter and cooler
Fuel filter and priming pump
Brake booster
Brake oil tank
AQGS unit
Washer fluid filler cap
Engine compartment fuse box
PTC relay box
Battery
Vacuum modulator (for VGT turbo charger) 1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.FFH Assembly (Only for vehicle with FFH)
Power steering oil tank
Engine oil filler cap
Fan shroud
E-EGR Valve
High-capacity PCV oil separator
HFM sensor (6.0)
VGT turbo charger
Air cleaner housing
2Coolant surge tank
ABS/ESP HECU (Including TPMS function:
optional)
Exhaust gas FRT Temp. sensor (T3) 14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
Page 519 of 600
Page 520 of 600
Page 525 of 600
1212-01
1. D27DT ENGINE STRUCTURE
1) Major Components in Engine and Engine Compartment
The advanced electronically controlled D27DT engine that has high pressure fuel system has
been introduced to this vehicle. It satisfies the strict emission regulation and provides improved
output and maximum torque.
1. Coolant reservoir
2. FFH device
3. Brake fluid reservoir
4. Washer fluid reservoir
5. Common rail6. Fuse box
7. Battery
8. Fuel filter
9. Power steering pump
10. Priming pump11. EGR valve
12. Air cleaner assembly
13. Turbo charger
14. Oil dipstick