Wide Ratio O2

[Steven Gorkowski]

Thanks for this information I needed the graphs to make a standard O2
sensor work and you and this company gave me this information. I have
used a standard O2 sensor in the past but without temp regulation and
temp sensing and agree that it is not as accurate as I need but if the
uC(pic) can regulate the heater so it is close to a temp curve . I can
build a meter for under $100 and will output A/f ratio to a standard
rs232 port.

Thanks again

Steve

garfield at pilgrimhouse.com wrote:

> On Thu, 26 Mar 1998 21:37:57 -0600, Steven Gorkowski <kb4mxo at mwt.net>
> wrote:
>
> >I do not get it, if I do 12 bit A/d conversion dividing the it into
> >4000+ pieces from 0 to 1v  and make a table so the table relates to
> A/f
> >ratio and compensate for temp. buy reading with therm. probe . Tell
> me
> >how the reading can't be accurate.
>
> Begs the question, dude. Most/all of them "el cheapo" meters are
> neither
> calibrated nor temp compensated. Thas THE problemo. I want you to take
> a
> look at a perfect example of an "el cheapo" sensor/box at:
>         http://www.splitsec.com/ego1/ego1ds.htm
> Scroll down far enough and you'll see their so-called "calibration"
> curves for their sensor/box. There are three curves show there, for
> 750degF, 1200degF, 1500degF, all very likely EGT temps observed in
> use.
> OK, now let's pick an example; we'll use yours of wanting to obtain
> max
> HP, which would be on the rich side of stoich, so look at the graph,
> and
> see what you read as far as AFR, if the sensor is outputting say 0.9V.
>
> Well, the AFR is either 12+, or 13+, or 14, depending on the temp!
> Somehow I don't think this is quite what you were hoping for, in terms
>
> of accuracy!? They don't have and so can't offer ANY data on
> determining/calibrating what the temp of the probe might be, nor are
> they implying that they even assume you'd be monitoring the ex-gas
> temps
> with a t-couple. I know this firsthand, because I talked to the
> designer
> for over a half-hour about his 'box', playing ignorant, and asking how
> I
> could use his device to actually MEASURE AFR. His final comment was,
> don't get too hung up on the AFR numbers; they're only
> "representative".
> Heh. Yeah.
>
> So yes, IF you use a fine grain transfer function, AND you map sensor
> output Vs to AFR, AND you map them along with measured probe (not even
>
> just EGT) temperatures, then YES you'll have a *measurement*
> instrument.
> But I dare say you won't find any of them el cheapo $100-$250 boxes
> that
> begin to meet ANY of them "IFs". And remember, my comments and your
> reply were in response to someone asking about using such an el cheapo
>
> to measure AFR, so I don't think I'm addressing a straw man. N'est ce
> pas?
>
> Garfield