Ox sender actual function

[Mark Wilcutts]

Just in case ANYONE is still interested in this subject...

I found an interesting paper that came out the following year by some Ford
people. It is SAE #930352 "Static Characteristics of ZrO2 Exhaust Gas
Oxygen Sensors". It sort of rebuts a few of the claims of the EPA paper
and presents a ton more data and references. If there's any interest, I
can scan and post a few pages. 


On Tue, 17 Nov 1998, Mark Wilcutts wrote:

> OK, I scanned the first two pages of the paper, if you're interested
> they're on my web site at:
> http://vehicle.me.berkeley.edu/~markw/efi/920289.html
> 
> I'm not an expert at scanning, and the pages require hand editing, so any
> additional pages may require quite some time. If you're interested in the
> paper I'd suggest ordering it from the SAE or finding an engineering
> school near you to photocopy it. 
> 
> (I hope the SAE doesn't kick my ass for copyright violation...)
> -- 
> Mark
> 
> On Wed, 11 Nov 1998, Mark Wilcutts wrote:
> 
> > I did a little digging and found the paper, it's SAE 920289 "Operating
> > Characteristics of Zirconia Galvanic Cells (Lambda Sensors) in Automotive
> > Closed-Loop Emission Control Systems" by Bozek, Evans, Tyree, Zerafa of
> > the EPA. I'll be taking a close look at this paper in the next few days.
> > 
> 
> > On Mon, 9 Nov 1998, Gregory A. Parmer wrote:
> > 
> > > > However, I believe here I once not to long ago heard someone mention that an
> > > > Oxygen sender in fact does not sense Oxygen as that would require higher
> > > > heat than present in most exhausts. That actually the sender senses carbon
> > > > particulate mater. What are the facts...
> > > 
> > > Apparently it senses CO and H.
> > > The following is taken from my beginnings of a FAQ that never got
> > > finished...it was posted by Dale Ulan on 28 Oct 94, I think.  This 
> > > version may be edited/abbreviated but a search of the archives will 
> > > get you the original post(s).  If you do the research and find the
> > > number of the mentioned SAE paper please let me know.  Isn't Dale 
> > > still here himself?
> > > -greg
> > > PS--the faq I started is at
> > > http://www.acesag.auburn.edu/~gparmer/efi/myfaq.html
> > > There are a few other O2 references also.
> > > 
> > > ------------------------------------------------------
> > > 
> > > About 1990, a few people from the EPA wrote an SAE paper on the subject of
> > > oxygen sensors. My copy of the paper is at school, so
> > >      I can't quote the names or give you the SAE paper number. But I can
> > > summarize it, because I was suprised, too.
> > >      The EPA was going to do a study of oxygen sensor aging and break-in
> > > periods, and quantify how this affects exhaust emissions. They
> > >      built a test setup with a heater (which would heat up the sensor and
> > > the gas it was exposed to), and a valving system that would allow
> > >      them to purge the test system with nitrogen gas, and then give
> > > samples of other gasses.
> > >      The most obvious test is to see what temperature was required for the
> > > sensor to sense oxygen. So they cranked up the O2 flow, and
> > >      started heating. The O2 sensor started to respond at about 800 or 900
> > > degrees C. No exhaust system operates at that under normal
> > >      road-load conditions.
> > >      At this point, they decided that their study should concentrate on
> > > this lack of O2 sensor activity. What they discovered was that the O2
> > >      sensor would respond to carbon monoxide and hydrogen. At normal
> > > operating temperatures, they concluded that the O2 sensor is not
> > >      capable of sensing oxygen at all. Few people seem to have read this
> > > paper, though, so most people out there think that the oxygen
> > >      sensor actually senses oxygen in a vehicle. It *can* sense oxygen,
> > > but it'll have to be glowing pretty bright to do it.
> > >      I would suggest going to your local technical library and finding
> > > this SAE article. It will be in one of the annual article abstract books,
> > >      somewhere between 1989 and 1993, and may be present in either the big
> > > thick SAE publication hardcovers, and/or in 'Sensors and
> > >      Actuators', an SAE special publication series (ref Dale Ulan --
> > > DIY_EFI email on 28 Oct 94). The output from an O2 sensor is shown
> > >      at http://www.bracken.co.uk/misc/ you will see a figure relating %
> > > O2, CO, H2, NOx etc to Lambda (ref Gus Cameron -- DIY_EFI
> > >      email on 24 Apr 1998).
> > > 
> > > 
> > 
> > 
> > 
> > 
> > 
> 
> 
>