4 ignition outputs from 3 inputs

[d-shiznit]

Heres my problem:
I want to use an Adaptronic ecu, which has 3 ignition outputs, for sequential ignition on a 4cyl engine.

So basicly I need an ignitor module which has 3 inputs to 4 outputs.. or some sort of decoder circuit / adressing scheme.

Does anyone know of any?

I was thinking Microtech x4 maybe - but I can't get any info on them - I've found that Microtech is terrible with tech info.

Any help / ideas appreciated!

[The Witzl]

why an adaptronic?

If it only has 3 ignition outputs, then it is clearly designed for use with a wasted spark system. It would be a massive headache to try and make it work otherwise, and involve MORE cost than spending that little extra over the cost of an Adaptronic to get something capable of what you want straight off the shelf

[JustCallMeOrlando]

The Microtech X4 is a dumb igniter, I know, I've got one. It has 4 inputs and 4 outputs. I'm with Witzl, if you really want direct fire ignition buy something else. Me personally, i'd be just using wasted spark and take advantage of the unique features of the Adaptronic.

[Mos]

So basicly I need an ignitor module which has 3 inputs to 4 outputs.. or some sort of decoder circuit / adressing scheme.

From a digital electronics perspective this is trivial. Use two of the lines to select which of the coils you want to trigger, then decode these two lines into four (plenty of binary decoder chips around - a CMOS 4028 will do it, or use some NAND gates), and then gate (eg using CMOS 4081 quad 2 input AND gates) the coil trigger signal (third output from ecu) to the correct ignitor.

You would need to be able to set up the ECU to output these signals correctly and you will need to work out if you'll need positive or negative logic to trigger the ignitors. You would also need to get all the timings correct so you don't trigger the wrong coil.

This exercise would probably not be worthwhile unless you do the design, research and implementation yourself. If you have to pay someone to do it, you would probably be better off going with one of the solutions already suggested.

HTH.
Mos.

[thechuckster]

a few big thing with sequential fire is:
-knowing where the cranks is as well as the cams (e.g. crank & cam trigger)
-being able to deal with false and missing triggers
-keep track of all that while firing at the right time (e.g. rpm versus MAP load map, temp compensation, accel compensation, etc).

coil selection is the easy part (as mos points out) and can be done with a minimal amount of code.

Just go waste-spark - unless you're running big boost, CoP isn't essential.

[Mos]

Just go waste-spark - unless you're running big boost, CoP isn't essential.

Unless the engine already has CoP (But then you can always fire two coils at once and save yourself the hassle for virtually no benefit).

Mos.

[pilot]

What kind of control system do you have to be able to get a difference between waste-spark and sequential ignition? Unless you are trying to overcome a stationary difference on the engine (geometrical difference in intake runners, for example) you won´t have any possible gain in doing this. You can always use a stronger igniter with a higher power coil.

[thechuckster]

Only reason i could think of for going CoP is to use something complex like multiple-spark CDI.

[pilot]

Coil on plug doesn´t equal sequential ignition.

[thechuckster]

agreed, poor choice of terminology. should read "sequential/individual coil"

chees,
charles.

[JustCallMeOrlando]

Direct Fire

[camrygt?]

The Adaptronic has 4 injector drivers and does full sequencial fuel injection on a 4 cyl so the code is all there. Its just that it only has 3 ignition drivers.

4 ignitors with inputs connected in parallel pairs of 2 firing 1 coil each will give virtually the same spark perfomance as full sequencial anyway.