I'm trying to build an ignition control module for my motorbike MZ ETZ 250.
I had change the ignition coil whit a low impedance 0.4, and now I need to adjust the dwell angle (dwell time) to keep alive my coil driver IGBT transistor.
The used microcontroller is Atmega 8 at 8 Mhz.
The software structure:
Read the ignition pickup (a hall sensor)transform in RPM when is RPM is equal with the preselected one, delay ON signal with the preset value from the map at that RPM, than turn ON the driver until the signal coming from pickup will be OFF.
The only thing what bother me is how often I need to adjust the delay time? The RPM sample I mean.
I think the optimal time is 3ms ON to charge the ignition coil enough.
Any suggestion are welcomed!