GF07.61-P-4009G ME-SFI Synchronization of Fuel Injection and Firing Order, Function
GF07.61-P-4009G ME-SFI Synchronization of Fuel Injection and Firing Order, Function
ENGINE 273 in MODEL 463.202 /222 /236 /237 up to 31.5.12
- as of model year 2009
/YoM 08
B6/4 Left intake camshaft Hall sensor
B6/5 Right intake camshaft Hall sensor
B6/6 Left exhaust camshaft Hall sensor
B6/7 Right exhaust camshaft Hall sensor
B70 Crankshaft Hall sensor
N3/10 ME-SFI [ME] control unit
R4 Spark plugs
T1/1 Cylinder 1 ignition coil
T1/2 Cylinder 2 ignition coil
T1/3 Cylinder 3 ignition coil
T1/4 Cylinder 4 ignition coil
T1/5 Cylinder 5 ignition coil
T1/6 Cylinder 6 ignition coil
T1/7 Cylinder 7 ignition coil
T1/8 Cylinder 8 ignition coil
Y62y1 Cylinder 1 injector
Y62y2 Cylinder 2 injector
Y62y3 Cylinder 3 injector
Y62y4 Cylinder 4 injector
Y62y5 Cylinder 5 injector
Y62y6 Cylinder 6 injector
Y62y7 Cylinder 7 injector
Y62y8 Cylinder 8 injector
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
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.
1 Crank angle (CKA)
2 Cylinder top dead center and firing order
3 Crankshaft Hall sensor voltage pulse
4 Engine speed signal
5 Voltage signal from LH and RH intake camshaft Hall sensor
6 Voltage signal from LH and RH exhaust camshaft Hall sensor
a Recognition of ignition TDC of cylinder 1
- Voltage pulse 3: second negative signal edge after the gap
- Voltage pulses 5 and 6: "low"
- Voltage pulse 4: changes from "high" to "low"
