Cylinder Balancing Strategy; Accelerometer Strategy; Balancing Of The Point To Point Flows; Resetting The Pilot Injection - SSANGYONG 2004 Rexton 2.7XDi Workshop Manual

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 succes-
sive 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.

Accelerometer Strategy

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.
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).
Major pilot injection
Minor pilot injection
No pilot injection
No injection
ENGINE CONTROL SYSTEM
DI ENG SM - 2004.4
Cylinder pressure
Needle lift
Ratio
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
DI08-17
Y220_08011