GF07.61-P-4009MIS ME-SFI Synchronization of Fuel Injection and Firing Order, Function
GF07.61-P-4009MIS ME-SFI Synchronization Of Fuel Injection And Firing Order, Function
- as of model year 09
Function requirements synchronization of fuel injection and firing order, general points
^ Circuit 87M ON (engine control ON)
^ Engine running
Synchronization of the fuel injection and firing order, general points
Synchronization of the injection and firing order is processed by the ME-SFI [ME] control unit in order to actuate the ignition coils (T1) and fuel injection valves (Y62)N3/10
Furthermore, the 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 (B70), engine speed and crankshaft position
- LH and RH intake camshaft Hall sensors (B6/4, B6/5), intake camshaft positions
- LH and RH exhaust camshaft Hall sensors (B6/6, B6/7), exhaust camshaft positions
Function sequence for synchronization of the fuel injection and firing order
When the engine is started, the injection sequence is determined according to the firing order, using the voltage signals from the crankshaft Hall sensor and the intake camshaft or exhaust camshaft Hall sensors. To do this, ignition TDC ( Top Dead Center) must be detected in cylinder 1.
At the 2nd negative signal edge following the gap in the signal from the crankshaft Hall sensor, the ME-SFI [ME] control unit detects the TDC position in cylinders 1 and 6. If the signal from an intake camshaft Hall sensor is at 0 V (low) at this time, the ME-SFI [ME] control unit processes it to detect ignition TDC in cylinder 1.
If the voltage pulse is missing from a camshaft Hall sensor the voltage pulse will be used as a substitute in a certain sequence by another camshaft Hall sensor for recognition of the ignition TDC of cylinder 1.
If no voltage signal is available from any of the camshaft Hall sensors, ignition and injection take place after 360° CKA ( CranK A ngle) 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 Identification:
Component Identification:
