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

ENGINE 651.9 in MODEL 204 (except 204.9), 204.9 up to 5/31/12 

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

ENGINE 651.9 in MODEL 218 up to 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 evaluation, the CDI control unit (N3/9) reads in the following sensors and signals:

IMPORTANT The Electronic Stability Program control unit will be used as of 1.3.2011 (model 204.0/2.) or as of 1.6.2011 (model 204.3) in 2 variants:

Until 28.2.2011 (model 204.0/2.) or 31.05.2011 (model 204.9) and as of 1.6.2011 (model 204.9) only the basic variant of the Electronic Stability Program control unit will be used.

Function sequence for smooth running control 

The function sequence is described in the following steps:

Function sequence for combustion misfire detection 

To do this the CDI control unit reads in the signal of the crankshaft position sensor (except code (B03) ECO start/stop function) or crankshaft Hall sensor (for code (B03) ECO start/stop function) and evaluates it for its uniformity. If lack of uniformity occurs on the crankshaft position sensor or crankshaft Hall sensor, the CDI control unit corrects the fuel pressure in the rails 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 drive train may have a negative effect on 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), is received by the CDI control unit via the chassis CAN from the Electronic Stability Program control unit or the Electronic Stability Program Premium control unit (for model (233) for DISTRONIC PLUS) (except model 204).

Fuel reserve signal 

The rear SAM control unit with fuse and relay module (N10/2) evaluates the signal from the left and right fuel level indicator fuel tank sensor (B4/1, B4/2) (model 204, 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 CDI control unit receives the fuel level information from the instrument cluster via the chassis CAN.

Sensor adaptation 

After adaptation of the crankshaft position sensor (except code (B03) ECO start/stop function) or crankshaft Hall sensor (for code (B03) ECO start/stop function) the tolerance range for smooth running analysis is reduced.

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