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
Page 546 of 600

1725-12
2. CDPF (EURO IV) SYSTEM CONTROL
1) Combustion Temperature and Procedures
As the soot is filtered in the CDPF, it is burnt and removed, and the CDPF is returned to the initial
state to collect the soot. Therefore, the burning procedures in the CDPF can be called as
regeneration.
The CDPF assembly is integrated with DOC (at front side) and DPF (at rear side).
The DPF burns the soot with high-temperature exhaust gas (over
The rear exhaust gas
temperature sensor monitors the temperature of DPF section. If this temperature is below the
regeneration temperature, the ECU increases the post injection period to increase the fuel
injection amount, and consequently to increase the exhaust gas temperature.
Front exhaust gas temperature sensor
(Measuring temperature of exhaust gas in
exhaust manifold)
Rear exhaust gas temperature sensor
(Measuring temperature of exhaust gas escaping DOC)
Normally, when the vehicle is driven for 600 ~ 1,200 km, the enough amount of soot to be
burnt is filtered and accumulated in the CDPF. The ECU increase the amount of post
injection to increase the tempeature of exhaust gas up to
so that the soot is burnt.
The soot is burnt for 15 ~ 20 minutes. -
Page 547 of 600

3) Post Injection and Air Mass Control
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 acumulated 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
the amount of fuel injected is increased to raise the
temperature. If the temperature is over
the amount of fuel injected is decreased or not
controlled.
When the engine is running in 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.
2) Sytem Composition for Soot Combustion
When the engine is running in low load range, the temperature of exhaust gas is decreased as the
amount of fuel supplied is decreased. To burn the soot filtered in the CDPF, the control system
should be installed to check the operating range and increase the temperature of exhaust gas by
controlling the amount of fuel supplied and intake air.
Two temperature sensors and one differential pressure sensor monitor the CDPF's operating
range. According to these sensors' information, the throttle flap decreases the intake air entered
to the throttle body. Also, the fuel injection pattern is added to increase the temperature of
exhaust gas for soot combustion.
There are three fuel injection patterns (pilot injection, pre-injection and main injection). As the
CDPF is installed, the post injection pattern is added.
Page 598 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.