Re: digital ignition

[brads@mindspring.com]

At 08:09 AM 12/28/98 PST, you wrote:
>I picked-up some info on a simple DIY electronic ignition system, using 
>a Motorola processor,  which allows you to ditch the distributor and 
>program your own custom ignition curve, via a PC serial interface. It 
>comes with circuit info, prototype software for the controller.  With 
>some minor modification, it could be adapted to use knock-sensor data to 
>optimise ignition timing and also an O2 sensor.

  That wouldn't happen to be the DDIS system using the 68HC11 designed by
Tim Drury, would it? 

> engine timing  :- I can't think of anything I can use to get engine 
>timing info.  Many systems use an inductor circuit on a toothed crank 
>pulley, which pulses each time a tooth passes the inductor. TDC is 
>marked with a missing tooth.

16V distributors have a hall sensor which has everything you need for
timing info. I can't remember if 8V have that as well? Sure a toothed wheel
on the crank pulley might be a bit more accurate, but you can make a good
system with just the hall senders, like VW did. Plus with the hall senders,
your circuit will be simpler than that for the DDIS.

Using most of the stock components, and just making your own "brain" would
be a bit simpler than having to fabricate all new sensors, housings,etc.


>Or even better, has anyone else done a similar project.

  Once or twice...

Brad


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