SsangYong Stavic / SsangYong Rodius (2005 year). Service manual — part 138
DI07-43
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
FUEL SYSTEM
DI ENG SM - 2004.9
It pushes the nozzle needle and
the control chamber opens (12)
The nozzle closes (13)
DI07-44
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
FUEL SYSTEM
DI ENG SM - 2004.9
• Small injection separation: min. 200
(duration between the end of pilot injection and start of
main injection)
• Opening Delay
: Delayed time from applying operating voltage to start of
injection
• Adjustment of feedback injection volume: C2I
Fuel pressure
Fuel pressure
• Minimum operating pressure: start injection over 100 bar
• Maximum operating pressure: 1,600 bar (max. operating pressure in normal conditions)
• Max overpressure: 2,100 bar
Maximum fuel volume at each injector cycle
• Pilot Injection
5 mm
3
• Main Injection
85 mm
3
(within 200 ~ 1,600 bar)
Pilot injection
Main injection
Small injection separation
Opening delay definition
Injection rate
Injector drive pulse
Time (
)
10%
signal
amplitude
10%
signal
amplitude
DI07-45
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
FUEL SYSTEM
DI ENG SM - 2004.9
Injector control
The control current of the coil takes the following form:
The low current allows the Joule effect losses in the ECU and injector to be reduced. The call current is higher than the
hold current because during the hold phase.
• The air gap between the valve and the coil is reduced and the electromagnetic force to be applied to the valve can
thus be reduced. It is no longer necessary to overcome the valve inertia.
Note
Joule Effect: The principle that the heat produced by an electric current is equal to the product of the resistance
of the conductor, the square of the current, and the time for which it flows.
I: current (A)
R: resistance (
Ω
Ω
Ω
Ω
Ω)
T: time (sec)
H: calori (cal)
Heat capacity (H) = 0.24 I
2
RT
Time
Hold period
Pull-in period
Through pull
current = 7.5 A
Current
Peak pull current
= 22.0 A
Through hold current
= 7.5 A
Peak hold current
= 22.0 A
DI07-46
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
FUEL SYSTEM
DI ENG SM - 2004.9
<Characteristic curve of discharge without pilot injection>
<Characteristic curve of discharge with pilot injection>
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.
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.
1. Pilot injection
2. Main injection
1a. Ignition pressure with pilot injection
2a. Ignition pressure without pilot injection
<Characteristic curve of combustion chamber pressure during pilot injection>
Needle lift (k)
Angle of crankshaft
Cylinder pressure (p)
Needle lift (k)
Cylinder pressure (p)
Angle of crankshaft
Angle of crankshaft
Pressure
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