ME-SFI synchronization of fuel injection and firing order, function - GF07.61-P-4009G
ENGINE 273 in MODEL 463.202/222/236/237 up to 31.5.12 as of model year 2009/YoM 08
Function requirements for synchronization of the injection and firing order for the ME-SFI gasoline injection and ignition system (engine electronics) (ME), general points
- Circuit 87M ON (engine control ON)
- Engine running
Synchronization of ME-SFI fuel injection and firing order, general points
Synchronization of the injection and firing order is processed by the ME-SFI [ME] control unit for actuation of the ignition coils and the fuel injection valves (Y62).
Furthermore synchronization is required for the knock control and the fuel shutoff on the individual cylinders.
The ME-SFI [ME] control unit synchronizes the injection and firing using the signals from the following sensors:
- Crankshaft Hall sensor, engine speed, crankshaft position
- LH and RH intake camshaft Hall sensor, intake camshaft positions
- LH and RH exhaust camshaft Hall sensor, exhaust camshaft positions
Synchronization of the ME-SFI fuel injection and firing order, function sequence
When the engine is started, the injection sequence is determined according to the firing order, using voltage signals from the crankshaft Hall sensor and the intake camshaft or exhaust camshaft Hall sensors. To do this, ignition TDC must be detected in cylinder 1.
The ME-SFI [ME] control unit detects TDC position in cylinders 1 and 6 on the 2nd. negative signal edge after the gap in the signal from crankshaft Hall sensor. If the signal from an intake camshaft Hall sensor is 0 V at this time, the ME-SFI [ME] control unit processes it in order to detect ignition TDC in cylinder 1.
If the voltage signal from a camshaft Hall sensor is missing, the voltage signal from another camshaft Hall sensor is taken according to a certain sequence and used as a replacement to detect ignition TDC in cylinder 1.
If no voltage signal is available from any camshaft Hall sensor, ignition and injection take place after a 360° crank angle in order to allow an emergency start.
When the engine is shut down, coasting detection takes place, which also evaluates the engine turn back shortly before standstill. During a computer run on by the ME-SFI [ME] control unit, the found rest position of the crankshaft as a °crank angle is stored and used for the next engine start.
If coasting detection does not produce a result, or the engine has been turned while shut down, injection and firing order are synchronized at engine start.
| Component description for ME-SFI [ME] control unit | N3/10 | GF07.61-P-6000G |