EGO sensors

[Alexander M. Lichstein]

I wonder if anyone has really read the info that IS out there regarding EGO
sensors.  The O2 sensor is measuring ALL exhaust gas components.  That means
SOx's, NOx's, CO, CO2, O2 etc.  In an earlier message I had included unburned
HC's, but someone pointed out that the ceramic catalyst which forms part of the
cell wouldn't allow [large] HC's to permeate.  In fact, this catalyst (at
600'C) WILL combust the HC's, and the products of this reaction will then be
able to permeate, so they [HC's] should be included in the analysis (and
remember that there are dozens of families and thousands of memebers).  In any
case, the point is that each of these gases will generate a potential in the
cell.  Each effective emf wil be different, and these must all be taken into
consideration.  It so happens that the exhaust components of a stoichiometric
combustion mixture will generally cause a potential of 0.45V (or so) to be
generated in the cell.  This has to do with the rapid increases of CO while the
O2 drops, NO peaks, and SO drops (lean to rich).  Off of this turning point, we
must know the relative partial pressures of each component (and those which are
generated by the catalysis of the HC's mentioned above) in order to predict
what voltage will be generated.  The point is that these relative components
will be a function of ,but not limited to: fuel composition, additives,
temperature, mixing, humidity,  altitude, barometriuc pressure, engine
size/weight/height, space-time continuum etc.  Under completely known and
repeatable conditions, it could be said that readings will be consistent.  But
I defy you to make a correlation based on all of the above under generalized
conditions.  Yes... anyone can linearize a graph, but not if it moves around as
seconds, days, and years go by.  These are my comments... I have more if you
need.

- Z