S07.10-0020-79
Block diagram |
B6/15 | Intake camshaft position sensor | Y62 | Fuel injectors | |
B6/16 | Exhaust camshaft position sensor | A | Mercedes-Benz | |
B70/2 | Crankshaft Hall sensor | B | Nissan | |
N3/34 | ME-SFI [ME] control unit | C | Default | |
T1 | Ignition coils | D | Optional |
Function requirements synchronization of fuel injection and firing order, general points
Circuit 87 ON (engine management ON)
Engine running.
Synchronization of fuel injection and firing order, general points
Synchronization of the injection and firing order is processed by the ME-SFI [ME] control unit (N3/34) in order to actuate the ignition coils (T1) and fuel injectors (Y62).
Furthermore, synchronisation is required for fuel cut-off at the individual cylinders. The ME-SFI [ME] control unit (N3/34) synchronizes the injection and ignition sequence on the basis of the signals from the following sensors:
Intake camshaft position sensor (B6/15), intake camshaft position
Exhaust camshaft position sensor (B6/16), exhaust camshaft position
Crankshaft Hall sensor (B702), engine speed and crankshaft position
Function sequence for synchronization of the fuel injection and firing order
The function sequence is described in the following steps:
Function sequence for synchronization
Function sequence for engine speed signal
Function sequence for synchronization
When starting the engine, the injection sequence is specified to match the firing order. To this end, the voltage signals of the crankshaft Hall sensor (B70/2), the intake camshaft Hall sensor (B6/15) and the exhaust camshaft Hall sensor (B6/16) are read in. The ignition top dead center (TDC) of cylinder 1 is detected by the crankshaft Hall sensor (B70/2).
Function sequence for engine speed signal
When the crankshaft is rotating, the teeth on the sensor wheel generate a voltage signal (alternating voltage) in the crankshaft Hall sensor (B70/2). Each tooth generates one voltage signal. The ME-SFI control unit (N3/34) receives the voltage signal and uses it to identify fluctuations in the engine speed.
If the voltage signal from the crankshaft Hall sensor (B70/2) fails, the voltage signal from the intake camshaft Hall sensor (B6/15) is used for emergency running. During limp-home mode running, the maximum speed is limited to 3000 rpm.