Fuel Injection; Pilot Injection; Main Injection - SSANGYONG 2004 Rexton 2.7XDi Workshop Manual

Fuel Injection

Other than conventional diesel engine, common diesel engine use two steps injection as follows:

• Pilot Injection

• Main Injection

In above two step injection, the fuel injection volume and injection timing is calibrated according to fuel pressure and fuel
temperature.
Pilot injection
Before starting main injection, a small amount of fuel is injected to help proper combustion. This injection is for reducing
the engine noise and vibration.
In other words, it makes the pressure increase in combustion chamber during combustion smooth to reduce the engine
noise and vibration (suppressing the surging). Basic values for pilot injection are adjusted according to the coolant
temperature and intake air pressure.
Angle of crankshaft
<Characteristic curve of discharge without pilot injection>
Main injection
Actual output from engine is achieved by main injection.
The main injection determines the pilot injection has been occurred, then calculates the injection volume. Accelerator
pedal sensor, engine rpm, coolant temperature, intake air temperature and atmospheric pressure are basic date to
calculate the fuel injection volume in main injection.
<Characteristic curve of combustion chamber pressure during pilot injection>
FUEL SYSTEM
DI ENG SM - 2004.4
Angle of crankshaft
Angle of crankshaft
<Characteristic curve of discharge with pilot injection>
1. Pilot injection
2. Main injection
1a. Ignition pressure with pilot injection
2a. Ignition pressure without pilot injection
DI07-59
Y220_07113
Y220_07114
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