[Diy_efi] Ion Sensing project

[Bruce]

Seems like most of this is self defeating.
You want a long duration spark to get the reaction, as complete as possible.
Sacrificng spark for detonation detection just doesn't seem like the best
solution, to me.
The reason for CDIs is because you run out of dwell time for a proper spark
with a auto transformer.   If you're not running a v8 at over 6K RPM there
is no NEED for CDI.   You can do better ignition wise with DIS or CNP.

Might be why GM has some paper on post chamber ion detection.
Bruce



----- Original Message -----
From: <bill.shurvinton at nokia.com>
To: <diy_efi at diy-efi.org>
Sent: Thursday, July 04, 2002 8:49 AM
Subject: RE: [Diy_efi] Ion Sensing project


Not multispark, you just keep the spark going (you have about 40uS to
recharge).

But even in the worst case with multispark you SHOULD have finished all of
that well before TDC. I suppose the issue is that the more clever you try to
be with the CDI, the more that the ion sensing needs to be closely coupled
to the ignition. Or to put it another way, as long as you know when the
spark decay occurs you can take that into account in the sampling.

Bill

-----Original Message-----
From: ext Ville Vartiovaara [mailto:vvartiov at cc.hut.fi]
Sent: 04 July 2002 13:15
To: diy_efi at diy-efi.org
Subject: RE: [Diy_efi] Ion Sensing project



> maintain the spark  was to recharge the capacitor half-way though to
> give a sawtooth, so the voltage will be much higher due to coil. But

Sounds like multispark, which is different idea, but not sure..

But for ion sensing it's important that:
- The spark decays fast (no multispark or similar)
- The ion sensing voltage is below minimum arc-maintaining voltage.
Supposedly that 400V





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