[Diy_efi] Ion Sensing project

[Bruce]

If you want to do a DIY CDI Dick Smith in Australia used to sell a CDI ki=
t,
for a rather resonable price, only down side was that you had to wind you=
r
own transformer for it
Bruce




----- Original Message -----
From: "William Shurvinton" <shurvinton at orange.net>
To: <diy_efi at diy-efi.org>
Sent: Thursday, July 04, 2002 3:22 PM
Subject: Re: [Diy_efi] Ion Sensing project


> I agree with Ville on this, in that that ION sensing is (in theory)
ignition
> agnostic. However, since you have to have a voltage generator at sround
> 400V, which just happens to be what CDI needs you can also use is to
charge
> a bank of capacitors for a CNP CDI system. By coupling the ignition and
ION
> sensing together you open up a number of interesting possibilities that
can
> keep the arc struck for a lot longer and get very good time control of
when
> the arc is extinguished.
>
> So you can have 50Kv to bridge the spark gap, then 50A or so to ensure =
a
> good fat flame kernel, hold it for 10=B0ish and turn it off just in tim=
e for
> the ION sensing to start it's stuff. All nicely adjustable and possibly
just
> what the doctor ordered for engines where the pesky combustion chamber =
is
> rotating whilst you are trying to light the mixture.
>
> CDI through a dizzy I 'personally' rate along side catalytic converters=
,
> chocolate tea pots and triumph herald suspension :-)
>
> Bill
> ----- Original Message -----
> From: Ville Vartiovaara <vvartiov at cc.hut.fi>
> To: <diy_efi at diy-efi.org>
> Sent: Thursday, July 04, 2002 3:18 PM
> Subject: Re: [Diy_efi] Ion Sensing project
>
>
> > > 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 th=
e
> best
> > > solution, to me.
> > > The reason for CDIs is because you run out of dwell time for a prop=
er
> spark
> > > with a auto transformer.   If you're not running a v8 at over 6K RP=
M
> there
> > > is no NEED for CDI.   You can do better ignition wise with DIS or C=
NP.
> >
> > As far as I remember, the CDI is being discussed here only to get som=
e
> > voltage level to compare to. :) Wheter it is CDI or not is not a prob=
lem
> > as long as the spark is done until TDC.. Shouldn't be a problem. ;)
> > And CDI has shorter decay time than a plain coil, so..



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