fuel pressure SSANGYONG NEW REXTON 2012 Workshop Manual

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

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

1212-01
Top View
19. Cylinder head cover
20. Intake manifold
21. Water outlet port
22. Common rail
23. Fuel pressure sensor24. Fuel pipe
25. Injector
26. Fuel return line
27. Oil filler cap
28. Glow plug29. Booster pressure sensor
30. PCV valve and oil separator
31. Oil dipstick
32. EGR-LH (#1) pipe

2) Common Rail
The orifice is added to the connection to
the fuel pipe of the HP pump to prevent
the fuel pulsation by the fuel supply and
fuel cut according to the increase of
injected fuel volume. (It is also installed on
the connection of the high pressure fuel
supply line of the HP pump.)D27DTP & D27DT (EU IV)
D27DT

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.