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Smooth running control, function - GF07.10-P-1011OMA

ENGINE 651.9 in MODEL 207, 212 (except 212.098/298) as of model year 2014 

ENGINE 651.9 in MODEL 218 as of model year 2014 

Function requirements for smooth running control, general points 

Smooth running control, general points 

Smooth running control reduces any rough running in the engine RPM range from 750 to 2600 RPM.

For smooth running control, the CDI control unit (N3/9) reads in the following sensors and signals:

Function sequence for smooth running control 

The function sequence is described in the following steps:

Function sequence for combustion misfire detection 

Here the CDI control unit reads in the signal from the crankshaft Hall sensor and evaluates its regularity. If lack of uniformity is evident from the crankshaft Hall sensor signal, the CDI control unit corrects the fuel pressure in the rail via the pressure regulating valve (Y74) and the quantity control valve (Y94) and the injection time via actuation of the fuel injectors (Y76).

IMPORTANT The fuel pressure in the rail and the injection timing of the fuel injectors produces the injection quantity.

Function sequence for factors for smooth running control 

The following factors affect smooth running control:

Recognition of road bumps 

Vibrations transmitted through the drivetrain may have a negative effect on evaluation of the engine running at certain engine speeds and load conditions. Therefore, the tolerance range for smooth running analysis is increased on poor road surfaces ("wash board").

The wheel speed signal (for recognition of an even wheel rotation) the CDI control unit CDI receives the fuel reserve signal via the chassis CAN 1 from Electronic Stability Program control unit (except code (233) DISTRONIC PLUS) or the Electronic Stability Program Premium control unit (with code (233) DISTRONIC PLUS).

Fuel reserve signal 

The rear SAM control unit with fuse and relay module (N10/2) evaluates the signals from the left and right fuel level indicator fuel tank sensor (B4/1, B4/2) (model, 207, 212) or left and right fuel level indicator fuel tank fill level sensor (B4/1, B4/2) (model 218) and outputs a corresponding signal to the instrument cluster via the interior CAN (CAN B).

The IC transmits the fuel level signal via the chassis CAN 2 (CAN E2) to the front SAM control unit with fuse and relay module; the signal is sent to the CDI control unit via chassis CAN 1.

Sensor adaptation 

The tolerance range for smooth running analysis is reduced after successful adaptation of the crankshaft Hall sensor.

In this way, the smooth running analysis can be adapted to the specific smooth running characteristics of the engine.

The CDI control unit stores the smooth operation characteristics of the engine during a deceleration phase (accelerator pedal not operated) when uniform smooth operation is present. These are required as a comparison parameter for misfire detection.

The tolerance range for smooth running analysis is preset in the CDI control unit and can be adapted using Xentry Diagnostics if necessary.

IMPORTANT On engines with Delphi injection system the smooth running control is called "Cylinder Balance Control".

  Electrical function schematic for smooth running control MODEL 207 PE07.10-P-2711-97EAN
MODEL 212 PE07.10-P-2711-97DAR
MODEL 218 PE07.10-P-2711-97XAH
  Overview of system components for common rail diesel injection (CDI)   GF07.16-P-9997OM
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