Smooth Running Control, Function - GF07.10-P-1011OGF

ENGINE 642.8 in MODEL 166 

as of model year 2016 

ENGINE 642.8 in MODEL 292 

Function requirements for smooth running control, general points 

• Circuit 87M (engine management ON)
• Engine runs

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 signals:

• Left hot film mass air flow sensor (B26), engine load
• Right hot film mass air flow sensor (B27), engine load
• Coolant temperature sensor (B11/4)
• Accelerator pedal sensor (B37), accelerator pedal position
• Crankshaft Hall sensor (B70), engine rpm
• Electronic Stability Program control unit (N30/4), wheel speed signal over chassis CAN 1 (CAN E1)
• Left fuel level indicator fuel tank fill level sensor (B41) and right fuel level indicator fuel tank fill level sensor (B42) via the SAM control unit (N10), the interior CAN (CAN B), the electronic ignition lock control unit (N73) and chassis CAN 1

Function sequence for smooth running control 

The function sequence is described in the following steps:

• Function sequence for combustion misfire detection 
• Function sequence for sensor adaptation 

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 a lack of uniformity occurs in the crankshaft Hall sensor signal, the CDI control unit corrects the fuel pressure in the rails via the pressure regulating valve (Y74) and the quantity control valve (Y94) and corrects the injection period by actuating the fuel injectors of cylinders 1 to 6 (Y76/1 to Y76/6).

The fuel pressure in the rails and the injection period of the fuel injectors combine to produce a specific injection quantity.

Function sequence for 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.

	Electrical function schematic for smooth running control		PE07.10-P-2711-97NBD
	Overview of system components for common rail diesel injection (CDI)		GF07.16-P-9997OGF