SSANGYONG Rodius 2012.07 Manual page 341

15-16
(4) Injection Timing Control
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Injection timing is determined by the conditions below.
1. Coolant temperature
Hot engine - Retarded to reduce Nox
Cold engine - Advanced to optimize the combustion
2. Atmospheric pressure
Advanced according to the altitude
3. Warming up
Advanced during warming up in cold engine
4. Rail pressure
Retarded to prevent knocking when the rail pressure is high
5. EEGR ratio
Advanced to decrease the cylinder temperature when EGR ratio increases
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Pilot injection timing control
The pilot injection timing is determined as a function of the engine speed and of the total flow.
The elements are:
-
A first correction is made according to the air and coolant temperatures. This correction allows the
pilot injection timing to be adapted to the operating temperature of the engine.
- A second correction is made according to the atmospheric pressure. This correction is used to adapt
the pilot injection timing as a function of the atmospheric pressure and therefore the altitude.
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Main injection timing control
The pulse necessary for the main injection is determined as a function of the engine speed and of the
injected flow.
The elements are:
- A first correction is made according to the air and coolant temperatures.
This correction makes it possible to adapt the timing to the operating temperature of the engine.
When the engine is warm, the timing can be retarded to reduce the combustion temperature and
polluting emissions (NOx). When the engine is cold, the timing advance must be sufficient to allow
the combustion to begin correctly.
- A second correction is made according to the atmospheric pressure.
This correction is used to adapt the timing advance as a function of the atmospheric pressure and
therefore the altitude.
- A third correction is made according to the coolant temperature and the time which has passed since
starting.
This correction allows the injection timing advance to be increased while the engine is warming up
(initial 30 seconds). The purpose of this correction is to reduce the misfiring and instabilities which are
liable to occur after a cold start.