Ignition Module, Function

Function of the Ignition Module

ENGINE 137.970




1 - 6 Cylinders 1 to 6
A Spark plug, ignition circuit a
B Spark plug, ignition circuit b
N3/10 Motor electronics control unit
N91 ECI ignition system mains unit
N92/1 ECI ignition module, right cylinder bank
A Microchip
B Switch-over between the main voltage of 180 volts and the auxiliary voltage of about 23 volt
C Output stages
D Uncoupling of the ion current signal
E Filtering of the ion current signal
N92/2 ECI ignition module, left cylinder bank

An L/C/R coil/condenser/resistance) - oscillating circuit with control and regulating circuit generates a 180 volt AC voltage (primary voltage) for every spark plug. This is then stepped up in the ignition coils above in the spark plug sockets to create the ignition voltage (secondary voltage).
Once ignition has taken place there is then a switch-over to the auxiliary voltage of about 23 volts. This is used to measure the ion currents at the spark plugs.
The ion current signal is decoupled in the ignition module, filtered and then transferred over a screened cable to the ME control unit.