2008 SSANGYONG KYRON ECU

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ENGINE FUEL SYSTEM
OVERVIEW AND OPERATION PROCESS
1. ELECTRONIC CONTROL OF FUEL SYSTEM
According to input signals from various sensors, engine ECU calculates driver's demand
(position of the accelerator pedal) and then controls overall operating performance of engine
and vehicle on that time.
ECU receives signals from sensors via data line and then performs effective engine air-fuel
ratio controls based on those signals. Engine speed is measured by crankshaft speed (position)
sensor and camshaft speed (position) sensor determines injection order and ECU detects
driver's pedal position (driver's demand) through electrical signal that is generated by variable
resistance changes in accelerator pedal sensor. Air flow (hot film) sensor detects intake ai
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volume and sends the signals to ECU. Especially, the engine ECU controls the air-fuel ratio by
recognizing instant air volume changes from air flow sensor to decrease the emissions (EGR
valve control). Furthermore, ECU uses signals from coolant temperature sensor and ai
r
temperature sensor, booster pressure sensor and atmospheric pressure sensor as
compensation signal to respond to injection starting, pilot injection set values, various
operations and variables.Components
High pressure fuel pump
Fuel injectors -
-Fuel rail
Electronic control unit(ECU) -
-Fuel pressure sensor
Various sensors and actuators -
-Supply line
Return line
ECU connecting line

ENGINE FUEL SYSTEM
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Fuel Line System
Fuel route
2. COMPOSITION OF FUEL SYSTEM
Components in fuel system are designed to generate and distribute high pressure, and they are
controlled electronically by engine ECU. Accordingly, fuel system is completely different from
injection pump type fuel supply system on the conventional Diesel engine. The fuel injection
system in common rail engine is composed of transfer pressure section that transfers fuel in
low pressure, high pressure section that transfers fuel in high pressure and ECU control
section.
High pressure pipe
Common rail
Fuel pressure
sensor
Priming pump
Fuel pump
(High pressure pump, transfer pump)
Fuel filter
Injector
D20DT: 4 EA
D27DT: 5 EA
common rail

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ENGINE FUEL SYSTEM
3) High Pressure Pipe (Fuel Pipe)
Fuel line transfers high pressure fuel.
Accordingly, it is made of steel to endure
intermittent high frequency pressure
changes that occur under maximum system
pressure and injection stops. Injection lines
between rail and injectors are all in the same
length; it means the lengths between the rail
and each injector are the same and the
differences in length are compensated by
each bending.
4) Injectors
The fuel injection device is composed of
electrical solenoid valve, needle and nozzle
and controlled by engine ECU. The injecto
r
nozzle opens when solenoid valve is
activated to directly inject the fuel into
combustion chamber in engine. When
injector nozzle is open, remaining fuel afte
r
injection returns to fuel tank through return
line.
Pressure limit valve, fuel returned by low
pressure and fuel used for high pressure
pump lubrication also return to fuel tank
through return line.
6) Fuel Filter Replacement
Fuel filter change interval: every 30,000 km
Water separation interval: every 10,000 km (same with engine oil change interval)
Never reuse the removed fuel filter -
-
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The transfer pump is included in the housing
of the high pressure pump. The transfe
r
pump is the volumetric blade type pump. To
deliver the continuously required fuel
volume, the pump transfers fuel from the fuel
tank to high pressure pump.
5) Transfer Pump

ENGINE INTAKE SYSTEM
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EGR Valve and Its Location
(* For details, refer to "EGR" section.)
Vacuum Modulator
Turbocharger Intercooler
The charging efficiency may be lowered or the
knocking may happen as the intake air is
heated and the density of air is lowered. The
intercooler is the device which cools the
supercharged air.
Intake
manifoldIntake
air
Exhaust
gasExhaust gasIntake manifold
Vacuum modulator
for turbocharger
actuator
EGR vacuum
modulator
Vacuum
pump EGR
valve
IP interior fuse (RH)
No.63-7.5AEngine ECU
No. 96
Intake Manifold
Intake air