2012 SSANGYONG KORANDO Service Manual

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2. Driver Demand
The driver demand is the translation of the pedal position into the fuel demand. It is calculated as a
function of the pedal position and of the engine speed. The driver demand is filtered in order to limit the
hesitations caused by rapid changes of the pedal position. A mapping determines the maximum fuel
which can be injected as a function of the driver demand and the rail pressure. Since the flow is
proportional to the injection time and to the square root of the injection pressure, it is necessary to limit
the flow according to the pressure in order to avoid extending the injection for too long into the engine
cycle. The system compares the driver demand with this limit and chooses the smaller of the 2 values.
The driver demand is then corrected according to the coolant temperature. This correction is added to
the driver demand.

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3. Idle Speed Controller
The idle speed controller consists of 2 principal modules:
The first module determines the required idle speed according to:
* The operating conditions of the engine (coolant temperature, gear engaged)
* Any activation of the electrical consumers (power steering, air conditioning, others)
* The battery voltage
* The presence of any faults liable to interface with the rail pressure control or the injection control. In
this case, increase the idle speed to prevent the engine from stalling.
The second module is responsible for providing closed loop control of the engine's idle speed by
adapting the minimum fuel according to the difference between the required idle speed and the
engine speed. -
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4. Flow Limitation
The flow limitation strategy is based on the following strategies:
The flow limitation depending on the filling of the engine with air is determined according to the
engine speed and the air flow. This limitation allows smoke emissions to be reduced during
stabilized running.
The flow limitation depending on the atmospheric pressure is determined according to the engine
speed and the atmospheric pressure. It allows smoke emissions to be reduced when driving at
altitude.
The full load flow curve is determined according to the gear engaged and the engine speed. It
allows the maximum torque delivered by the engine to be limited.
A performance limitation is introduced if faults liable to upset the rail pressure control or the
injection control are detected by the system. In this case, and depending on the gravity of the fault,
the system activates: -
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Reduced fuel logic 1: Guarantees 75 % of the performance without limiting the engine speed.
Reduced fuel logic 2: Guarantees 50 % of the performance with the engine speed limited to 3,000 rpm.
Reduce fuel logic 3: Limits the engine speed to 2,000 rpm.
The system chooses the lowest of all values.
A correction depending on the coolant temperature is added to the flow limitation. This correction makes
it possible to reduce the mechanical stresses while the engine is warming up. The correction is
determined according to the coolant temperature, the engine speed and the time which has passed
since starting.
Superchager Flow Demand
The supercharge flow is calculated according to the engine speed and the coolant temperature. A
correction depending on the air temperature and the atmospheric pressure is made in order to increase
the supercharge flow during cold starts. It is possible to alter the supercharge flow value by adding a flow
offset with the aid of the diagnostic tool.

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5. Pilot Flow Control
The pilot flow represents the amount of fuel injected into the cylinder during the pilot injection. This
amount is determined according to the engine speed and the total flow.
A first correction is made according to the air and water temperature.
This correction allows the pilot flow to be adapted to the operating temperature of the engine. When
the engine is warm, the ignition time decreases because the end-of-compression temperature is
higher. The pilot flow can therefore be reduced because there is obviously less combustion noise
when the engine is warm.
A second correction is made according to the atmospheric pressure. -
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During starting, the pilot flow is determined on the basis of the engine speed and the coolant
temperature.
6. Cylinder Balancing Strategy
Balancing of the point to point flows ▶
The pulse of each injector is corrected according to the difference in instantaneous speed measured
between 2 successive injectors.
The instantaneous speeds on two successive injections are first calculated.
The difference between these two instantaneous speeds is then calculated.
Finally, the time to be added to the main injection pulse for the different injectors is determined. For each
injector, this time is calculated according to the initial offset of the injector and the instantaneous speed
difference.
Detection of an injector which has stuck closed ▶
The cylinder balancing strategy also allows the detection of an injector which has stuck closed. The
difference in instantaneous speed between 2 successive injections then exceeds a predefined threshold.
In this case, a fault is signaled by the system.

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e. MDP Learning Control
MDP (Minimum Drive Pulse ) refers to the
minimum power supply pulse for injection which
the injector can perform. It is possible to control
the fuel volume for each injector accurately
through correct learning for the MDP value. The
basic process of MDP learning is that the pulse
slightly higher than MDP is supplied and then (b)
the vibration generated from the cylinder is
detected. The knock sensor detects the vibration
from the engine after a small volume of fuel is
injected. And the time interval between the points
of injection and vibration is measured so that
MDP can be learned. MDP learning is helpful to
prevent engine vibration, high emission and
power reduction through performing calibration
for the old injectors. During MDP learning, a little
vibration and noise can be occur for a while. This
is because the fuel pressure is increased
instantaneously and the exact injection value is
not input, so that the exact engine vibration
timing can be detected.

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(3) Accelerometer Control
a. Resetting the pilot injection
The accelerometer is used to reset the pilot injection flow in closed loop for each injector. This method
allows the correction of any injector deviations over a period of time. The principle of use of the
accelerometer is based on the detection of the combustion noises.
The sensor is positioned in such a way as to receive the maximum signal for all the cylinders. The raw
signals from the accelerometer are processed to obtain a variable which quantifies the intensity of the
combustion. This variable, known as the ratio, consists of the ratio between the intensity of the
background noise and the combustion noise.
A first window is used to establish the background noise level of the accelerometer signal for each
cylinder. This window must therefore be positioned at a moment when there cannot be any
combustion.
The second window is used to measure the intensity of the pilot combustion. Its position is such that
only the combustion noises produced by the pilot injection are measured . It is therefore placed just
before the main injection. 1.
2.
The accelerometer does not allow any evaluation of the quantity injected. However, the pulse value will
be measured when the injector starts injection and this pulse value is called the MDP (Minimum Drive
Pulse). On the basis of this information, it is possible to efficiently correct the pilot flows. The pilot
injection resetting principle therefore consists of determining the MDP, in other words the pulse
corresponding to the start of the increase in value of the ratio (increase of vibration due to fuel
combustion).

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This is done periodically under certain operating conditions. When the resetting is finished, the new
minimum pulse value replaces the value obtained during the previous resetting. The first MDP value is
provided by the C3I. Each resetting then allows the closed loop of the MDP to be updated according to
the deviation of the injector.
b. Detection of leaks in the cylinders
The accelerometer is also used to detect any injector which may have stuck open. The detection
principle is based on monitoring the ratio. If there is a leak in the cylinder, the accumulated fuel self-
ignites as soon as the temperature and pressure conditions are favorable (high engine speed, high load
and small leak).
This combustion is set off at about 20 degrees before TDC and before main injection.
The ratio therefore increases considerably in the detection window. It is this increase which allows the
leaks to be detected. The threshold beyond which a fault is signaled is a percentage of the maximum
possible value of the ratio.
Because of the severity of the recovery process (engine shut-down), the etection must be extremely
robust.
An increase in the ratio can be the consequence of various causes:
Pilot injection too much
Main combustion offset
Fuel leak in the cylinder -
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If the ratio becomes too high, the strategy initially restricts the pilot injection flow and retards the main
injection. If the ratio remains high despite these interventions, this shows that a real leak is present, a
fault is signaled and the engine is shut down.
c. Detection of an accelerometer fault
This strategy permits the detection of a fault in the sensor or in the wiring loom connecting the sensor to
the ECU.
It is based on detection of the combustion. When the engine is idling, the detection window is set too low
for the combustion caused by the main injection. If the ratio increases, this shows that the accelerometer
is working properly, but otherwise a fault is signaled to indicate a sensor failure. The recovery modes
associated with this fault consist of inhibition of the pilot injection and discharge through the injectors.

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HFM
Accelerator pedalCoolant
temperature
(4) Swirl control
a. Overview
Variable swirl valve -
The strong swirl caused by intake air is important element for anti-locking function in diesel engine. The
swirl control valve partially closes the intake port to generate the swirl according to the engine conditions.
When the engine load is in low or medium range, the swirl could not be generated because the air flow
is slow. To generate strong swirl, there are two passages in intake manifold, and one of them has the
valve to open and close the passage. When the valve closes the passage, the air flow through the
another passage will be faster, and the strong swirl will be generated by the internal structure of the
passage. This swirl makes the better mixture of air and fuel, eventually the combustion efficiency in
combustion chamber could be improved. This provides the enhanced fuel consumption, power and
EGR ratio.
Components -
D20DTF ECU
Crankshaft
position sensor
Variable swirl
valve

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b. Input/Output for variable swirl valve