SsangYong Stavic / SsangYong Rodius (2005 year). Manual - part 145

DI08-17

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ENGINE CONTROL SYSTEM

DI ENG SM - 2004.9

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 C2I. Each
resetting then allows the closed loop of the MDP to be updated according to the deviation of the injector.

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 strong

• Main combustion offset

• Fuel leak in the cylinder

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.

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.

DI08-18

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ENGINE CONTROL SYSTEM

DI ENG SM - 2004.9

INDIVIDUAL INJECTOR CALIBRATION (C2I)

Injected fuel is proportional to square root of injection time and rail pressure.

It is function between pulse and rail pressure and fuel injection curve is called injector characteristics curve having the
following shape.

Common rail injectors are very accurate components. They are able to inject fuel delivery between 0.5 to 100 mg/str
under pressure varying from 150 to 1600 bar.

This high level of accuracy requires very low machining tolerances (few 

).

Nevertheless, due to the machining dispersion, the loss of charge through the functional orifices, the friction between
moving parts and electromagnetic field level are different from one injector to the other. So, the difference of fuel delivery
for the same pressure and the same pulse can reach 5 mg/str from one injector to the other. It is impossible to control
efficiently the engine with such a dispersion between the different injectors. It is necessary to add a correction that
allows injecting the demanded fuel delivery whatever the initial hydraulic characteristics of the injector is. The method
consists in correcting the pulse that is applied to the injector with an offset that depends on the initial hydraulic map of
the injector. So, the pulse should be corrected according to characteristics of each injector.

Delivery (mm

3

/st)

Drive pulse (

µsec)

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ENGINE CONTROL SYSTEM

DI ENG SM - 2004.9

C2I is composed of models on these characteristics of injectors.

C2I consists of 16-digit; composed of numbers from 1 to 9 and alphabets from A to F. ECU remembers C2I, character-
istics of each injector, to make the most optimal fuel injection.

• When replacing the injector, C2I code on the top of new injector should be input into ECU because the ECU is

remembering the injector’s C2I value. If C2I is not input, engine power drops and occurs irregular combustion.

• When ECU is replaced, C2I code of every injector should be input. If not, cannot accelerate the vehicle even when

the accelerator pedal is depressed.

For coding of C2I, refer to “Diagnosis” section

C2I Number

(16 digits)

C2I

value

DI08-20

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ENGINE CONTROL SYSTEM

DI ENG SM - 2004.9

MINIMUM DRIVE PULSE (MDP) LEARNING

When the pulse value that the injector starts injection is measured, it is called mininum drive pulse (MDP). Through MDP
controls, can correct pilot injections effectively. Pilot injection volume is very small, 1 ~ 2 mm/str, so precise control of
the injector can be difficult if it gets old. So there needs MDP learning to control the very small volume precisely through
learning according to getting older injectors.

Learning Conditions

Coolant temperature

Vehicle speed

Intake manifold pressure

Engine speed

Battery voltage

Fuel temperature

Initial MDP learning on each injector

> 75°C

> 50 Km/h (over 5 seconds)

> 0.7 bar

> 2,500 rpm

10 V < MDP < 16 V

0 < fuel temperature < 80°C

5 seconds

Trouble Codes

Trouble code

P1171

P1172

P1173

P1174

P1175

Description

Fault MDP learning on injector No. 1

Fault MDP learning on injector No. 2

Fault MDP learning on injector No. 3

Fault MDP learning on injector No. 4

Fault MDP learning on injector No. 5

Diagnosis

• Check each injector