ION-related IGN Comments & Coil Quest

[Bruce Plecan]

Subject: ION-related IGN Comments & Coil Quest

All the General Motors Distributorless Coils are four terminal.
Cheers
Bruce



>Hey Maties.
>
>I had a brain-flash (or fart, we'll see shortly) whilst looking over the
>DSE schematics for their CDI plans/article.
>
>[SIDEBAR: the circuit and assembly is DIRT simple, and looks well thot
>out and done (true, the pc board is a disappointment cuz of it's size,
>but they wanted one you could do at home, I guess. Me I'd cram it in
>niceNtight on a piece of two-plane thru-hole 0.1" perf board), and the
>only "custom" part is really doable with anyone with two hands and half
>a brain-stem; it's the main inverter transformer, and the plans call out
>all the particulars and part nos. for the bobbin/core and other pieces
>from Philips you need to buy to assemble this "custom" transformer. The
>parts list is quite detailed in that respect; major kudos for that.
>Sooo, nuthin esoteric or hard about this one "custom" transformer.
>Sounds daunting but it's really a pieceOcake no-brainer.]
>
>The guy's design (John Clarke...anyone on the list from Oz know him,
>BTW?) is for use with stock IGN coils. So while tryna think-out an ION
>circuit that doesn't need HV diodes, and still can use the stock coils,
>and having troubles seeing how that's EVER gonna be possible, the thot
>struck me... HEY, I'll ask all them bloaks on diy_efi if ANYONE has ever
>seen a so-called 4-terminal stock auto IGN coil? What I mean by that is,
>consider the normal IGN coils we're all used to. They're basically a
>3-terminal device; one terminal is the HV output (the "top" of the
>secondary, if you will), and then there's a "shared/common" connection
>for both primary and the other side of the secondary, and then the third
>terminal, which is for the primary feed. So you essentially have what we
>used to call an auto-transformer, or a transformer with a common
>connection for both primary and secondary.
>
>Now, what would be REALLY ideal for ION is a stock automotive IGN coil,
>but one that has it's primary and secondary completely independent (no
>common'd terminal), so you have a 4-terminal device, with three pins on
>the low voltage connector, and one for the HV secondary output.
>
>So, there's the bottom line question, maties; anyone every seen such a
>beastie? I and my Napa pal went through our books and his inventory this
>afternoon, even called Echlin, but couldn't come up with anythin. Of
>course, we don't give a rip what shape or form it's in for eXperimental
>purposes, but I'd sure be grand if a real "in-situ" coil existed we
>could also use with the real ION. Ask around, see what you can come up
>with; I'm certain that IF such a beastie exists, sooner or later someone
>on the list will exhume it!
>
>Meanwhile, I'm still slowly working on my "patent commentary" and
>example circuits, so it's comin.
>
>Hey, BTW, I had another somewhat bizarre thot, incase we CAN'T find such
>a coil to play with, that even with box stock IGN systems, and NO mods,
>one could actually build some lil adapter blocks that went between the
>HV lead and the plug top, and using some few HV diodes (there's nuthin
>wrong with them, BTW, they're robust and failsoft, it's just that I'm
>stuck on being able to do the "elegance" thang like Saab did, where THEY
>don't need any atoll), you could ADD the ionization detection into an
>existing IGN system, on a per-plug basis. I see absolutely nuthin that
>would prevent this, EXCEPT we still don't know if the longer spark
>duration of inductive IGN is gonna "blank" critical portions of the IGN
>phase. But, yeah, even the idea that MikeMorrin suggested might be
>possible, in that these "inserted measurement blocks" could actually
>quench the "tail" of the inductive spark early and MAKE a window for ION
>to do it's measurement magic. That too might be possible.
>
>I only mention this possibility because IF we could make this work, if
>only for eXperimental purposes, it would allow dyno tuners and others to
>LEAVE their acoustic knock detectors on the engine, and COMPARE the
>"indicator and measurement" functionality of one vrs the other, and
>REALLY determine if ION is giving you anything back. The reason I
>mention dyno tuners in particular is they have the easiest time in
>dialing in a forced "knock" on command. The rest of us have to tweak
>timing manually, and be careful we don't overdo it with load and
>throttle. I know there are several guys on the list that could do this
>comparison, so this too is another avenue of eXperimentation. Here, I
>don't think the "ionization circuit" per se is the
>difficult/questionable part, but rather what to do with the stock
>inductive IGN system's spark duration.
>
>Thas all fer now. Scan yer personal archives and see if you've ever seen
>a "4-terminal" IGN coil. Any feedback appreciated.
>
>Gar
>
>