Synchronize Fuel Injection And Firing Order Function - GF07.10-D-1006TSB

Engine 274 in model 907

Block diagram

Function requirements

Circuit 87M (Engine management ON)
Engine running.

Function

Synchronization of the injection and firing order is processed by the ME-SFI [ME] control unit (N3/36) in order to actuate the ignition coils (T1) and fuel injectors (Y62).

Furthermore, synchronization is required for knock control and fuel shutoff on the individual cylinders. The ME-SFI control unit synchronizes the injection and firing order using the signals from the following sensors:

Intake camshaft Hall sensor (B6/29)
Exhaust camshaft Hall sensor (B6/30)
Crankshaft Hall sensor (B702), engine speed and crankshaft position

Function sequence

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 do this, the voltage signals are read in by the crankshaft Hall sensor and the camshaft Hall sensors. The ignition TDC (top dead center) of cylinder 1 is detected by the crankshaft Hall sensor.

Function sequence for engine speed signal

Using the signal from the crankshaft Hall sensor, the ME-SFI [ME] control unit generates the short circuit-proof engine speed signal (e.g. for cold testing and diagnosis) and outputs it to the powertrain CAN (CAN C).

direction recognition

If the engine rotates backwards, something which can only happen sporadically, briefly before standstill, after the engine has been stopped, then the pulse duration for the 0 volt-pulse is altered. The ME-SFI [ME] control unit can thereby determine any change in direction of rotation and thus record the exact angular position of the crankshaft at any given time.

This information is required, in particular, when quickly starting the engine in the ECO start/stop mode.

Electrical function schematic, synchronization of the injection and firing order	PE07.10-D-2706-97TSA
Overview of system components for gasoline injection and ignition system with direct injection	GF07.70-D-9998TSB