I made a multiple spark CD ignition system for my HND back in 1984. Loosely (very) based upon a project in a magazine to give me a starting point..
I wound my own transformer, with antiphase feedback driving the base of a push-pull inverter to create some BIG kilovolts to charge the discharge capacitors, which were fired off three thyristors. The firing was triggered off a decade counter chip and it had some discrete components too to supply dc to the digital triggering section. The output fed into a car coil and single spark plug.
Running it all from a car battery, and using a square wave generator to simulate the points switching, it showed up on the analyser in the car lab at college, to have three big CD pulses at the sparkplug in the time it took normally for one to happen.
Due to the reactance of the system it wouldnt run faster that 3000rpm (simluated).
I innovated, designed, built and docummented the whole caboodle in two years. Got a lot of grief from a couple of lecturers as it didn't involve an interface for a ZX81/Spectrum/Pet PC. But the old heads in the dept thought is was ace. Wasn't perfect, but it worked!
Still got it here.. Its a bit tatty, but I can't bear to dump it. Still got the draft of the documentation too. Even made my own pcb's for it!
Was always doing car crap in my spare time.. Using a DMS600 discharge relay and a bank of nicds, I made a neat wee ignition booster that put more current into the coil of my old Escort that was depleted by the use of the starter motor. It totally discharged upon firing, but charged again for use the next time. Seemed to work as it always started easily.
Could I repeat such nonsense these days? Doubt it.. Don't even ask me what I did with a colour tv flyback t/f, ten voltage multpliers from Diascopes and two nails in bit of board!! Apparently creating your own O3 ozone is bad for the sinuses!! ..hahaha!!
