O2 sensor question

[Dave & Irina Eicher]

Interesting stuff Gar, appreciate the info. Do you have a feel for when the
meter design will be ready for public consumption?

thanks, dave

----- Original Message -----
From: Garfield Willis <garwillis at msn.com>
To: <diy_efi at diy-efi.org>
Sent: Thursday, March 23, 2000 2:46 PM
Subject: Re: O2 sensor question


> On Fri, 24 Mar 2000 03:02:33, "Mike (Perth, Western Australia)"
> <erazmus at wantree.com.au> wrote:
>
> >At 11:07 AM 22/3/2000 -0800,  garwillis at msn.com (Garfield Willis) wrote:
> >
> >>For those unfamiliar, "EGOR-the-module" is an interface for a
> >>current-pump-style NTK-Honda 5-wire wideband sensor, basically it's a
> >>black-box with pins, around which you'll be able to build a
> >>WOT/wideband-O2 engine manager; and "EGOR-the-meter" is a hand-held
> >>precision AFR meter with large digital and bar-graph display (and an
> >>analog out for logging, of course), useful for tuning/cal work.
> >
> >Are there any specs for the sensor ?
> >
> >I'd like to integrate the display into my own equipment,
> >
> >Tah
>
> Hey, one thing I gotta know...what's this "tah" interjection you often
> use, mean in WestOz? Is it like a grin, or a "heh heh" or "hee hee" like
> we do in the States? I've never seen it before and kinda appreciate the
> general Aussie verbal style, so I had to ask. If it's difficult (or
> embarrassing) to convey via public typing, don't sweat it.
>
> Anyway, on to your question. This has been explained before, but this
> type of sensor (the Honda-NTK sensor is one of the so-called
> "current-pump" types) REQUIRES a special sort of interface electrics to
> go with it. It's not merely a passive sensor like the older "Nernst" or
> switch type sensors, which just put out a voltage you read. There's a
> little pump inside these new sensors that squirts oxygen ions into (or
> out of) another measurement cell, in an attempt to balance out excess or
> depletion of oxygen in the exhaust gas. This clever trick is what allows
> these sensors to be so "linear" and good as O2 measurement devices, but
> makes operating the sensor more complicated than the older type.
>
> EGOR *is* that special interface electrics. If you want to roll your own
> display, you could use just an EGOR-module, and build your own
> instrument around that, but when you see how snarky and inexpensive our
> EGOR-meter is going to be, you'll probly just go for that instead.
>
> This discussion allows me to add another comment/recommendation about
> how to plan for using these sensors. Ya know, they're all still pretty
> spendy, even with the Honda sensor available with a goodly discount over
> the net for slightly less than $100, that's still a pretty decent
> chunkOchange for "consumables". I would think twice about planning on
> having such a sensor left in the exhaust ALL the time, and part of your
> normal everyday panel meters. Everybody knows that rich running, oil
> burning, and lead mix all contribute to shorter lifetimes for these
> sensors. Add to that the fact that any heated sensor has a VERY hot
> ceramic bit in them that can be instantly fractured if clobbered by a
> errant drop of water from a cold exhaust system. All it takes is
> condensation in the wrong place, a (perhaps unbeknownst to you) poorly
> chosen placement of the O2 bung, and all these things may put you in the
> position of test engineer where the supplies of sensors is paid for out
> of your own pocket. The auto mfgs. found out about those types of
> mistakes and paid for them (usually, hopefully) during engineering
> trials. You might want to avoid those costs if possible.
>
> Sure, you're gonna go for it if you're planning on a WOT/wideband ECU,
> because you don't have any choice, and you need that WOT tight control
> to get your track times down, or whatever. But if you're using it for
> tuning and tweaking your open-loop fuel maps in your EFI controller from
> time to time, I'd suggest you consider it a hand-held instrument that
> you use via a tail-pipe probe, and you only expose the sensor to these
> attendant dangers whenever you need to be performing those kinds of
> measurements. On the front panel of the EGOR-meter right below the ON
> switch, you're gonna see a litany of cautions (like a pilot's checklist,
> if you will) to help you avoid damaging the sensor, just because the
> bloody things still cost $100, and in most places that can still buy a
> nice dinner for two. But of course, it's everyone's choice. I'm just
> trying to point out some realities of the situation. Everything possible
> has been done to keep the deployment of this cool measurement technology
> as absolutely low-cost as possible. So the clients we're targeting we
> just ASSUME will want to be very careful with their sensors and baby
> them. But if your gameplan (e.g., WOT controller) or robust pocket
> change allows it, sure go for a permanent wideband sensor in your
> exhaust full-time, and use an EGOR-module to interface that sensor to
> your own custom electrics. That is one of the uses it's intended for,
> except we think mostly for both economy and appreciating the finer
> things in life, if you're not building an engine manager, you'll
> probably find our meter irresistible. :)  But like I said before, both
> the module and meter are going to be very affordable, so the choice will
> be yours.
>
> Gar
>
>
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