ION Project Papers & Info Sources

[Joachim M. Wagner]

HI, Gar

sounds great what you have found out! What influence does this ion sensor
have on the e.f.i. or ignition system?? And what are the output signals
created from ECU given to the engine???

Joachim 

----------
> Von: garfield at pilgrimhouse.com
> An: diy_efi at efi332.eng.ohio-state.edu
> Betreff: Re: ION Project Papers & Info Sources
> Datum: Samstag, 9. Mai 1998 08:45
> 
> On Fri, 08 May 1998 21:57:05 -0700, garfield at pilgrimhouse.com wrote:
> 
> >On Fri, 08 May 98 19:37:02 -0700, Andrew Ghali <andrewg at netcom.com>
> >wrote:
> >>http://www.mecel.se/my_html/body_Ion_Sense.htm
> >>
> >>It mentions that Mecel has a patent issued in 1984 on ionization
current
> >>measurement used in Saab's DI system.
> >
> >Excellent little blurb there.
> 
> Just a couple follow-up comments and some NEWS. In looking at Mecel's
> page a lil more, I see that the DI system (which DOES include ion
> sensing for cylinder commutation) was intro'd in '87, which means this
> stuff IS 10 years old. The other thing to note is that although the
> patent was issued in '84 and deployed in '87, there is a real dearth of
> articles/papers until the mid-ninties. In larger corporate circles, this
> usually means there was a "ban" on publishing sensitive info until
> several years and cash cows could be harvested. This is a likely
> indication that Saab WAS INDEED tryna keep the stuff secret for quite a
> few years.
> 
> Now the bit of news. You will note on the Mecel page that there's been a
> DI system in the 9000s since 87/88? Well, a buddy of mine, who manages a
> Saab parts dept. and whom I've been plying with questions since this all
> started, today came up with some notes and a warrantee unit from a '90
> Saab, and the lil board that does the Ion Detection stuff in those
> earlier models is readily viewable (unlike the later models, that are
> SERIOUSLY potted) if you remove the protective covers. On that lil board
> that stands up like a "module" SIP, the ONLY active parts are an LM-139
> Quad Comparator (SGS-Thomson variety with cerdip and -25 to +125degC
> rating, so them guys know what they're doin) and a lone transistor. A
> sprinkling of the usual diodes and passive discretes, of course, but the
> point IS, it ain't no special sauce or any analog black magic, cuz there
> ain't even no op amps, so if there IS any filtering it's of the lowliest
> kind, since there is no active filtering possible on this board. I
> traced the circuit out enough to know for sure this IS the module that
> does the ion detection, cuz two of them comparators directly drive the
> signals that say which cylinder is firing. This is EXTREMELY
> encouraging, cuz if we can understand this technology, the circuitry to
> implement it obviously is pretty dirt simple AND dirt cheap. As a result
> of this latest intel, I am even more confident that after digesting the
> available papers and summing up all our fractional wits, we're VERY
> likely to get a workable DIY implementation. ION is beginning to smile
> upon us, methinks. Maybe if we're nice to her, she's tell us her
> secrets. B)
> 
> Gar
>