ME-SFI synchronization of fuel injection and firing order - function - GF07.61-P-4009BK

ENGINE 113.967 in MODEL 219 

ENGINE 113.964 in MODEL 164.1 

ENGINE 113.971 in MODEL 251 

When the engine is started, the injection sequence in line with the firing order is defined on the basis of the signals supplied by the crankshaft position sensor and the camshaft Hall sensor.

Fig 1: Fuel Injection And Firing Order Communication Diagram

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Signal assignment 

Fig 2: Crankshaft Position Sensor Signal Graph

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

When the crankshaft is rotating, an alternating voltage is generated in the crankshaft position sensor by the teeth of the driven plate. During this operation, each tooth generates an alternating voltage signal. No voltage is generated as a result of the gap created by 2 missing teeth.

The engine control unit detects the TDC position of cylinders 1 and 6 from the 2nd negative slope after the gap.

If, at this moment, the signal from the camshaft Hall sensor is at 0 volt ("low") the ME control unit processes this in order to detect ignition TDC of cylinder 1.

Synchronization of the fuel injection and firing order is further processed by the ME-SFI control unit for actuating the ignition coils and the fuel injectors.

In addition the synchronization is required for the anti-knock control and the fuel cut-off on the individual cylinders.