O2 Volts

[rr]

Bruce Plecan wrote:
> 
> Now, to me rather than go on,, with further testing while it might settle a
> curiousity, it doesn't help with what my goal is.
>   If you think about it, there are so many variables that on any one day,
> you can ask, where are things?.  ie O2 level, in the atmosphere varies day
> to day, along with other "rare" chemicals. that might contaminate the
> results.
>   In the oem applications they supply a reference voltage which as to effect
> the ionization, and performance of the O2 v generating strategy.
> 
>   The useful facts as I see them are:
>   In cold weather, a none heated O2 sensor can go open loop. due to the O2
> sensor being too cold.  A heated O2 develops enough heat so that it can
> "properly sense" the needed gases to operate.
>   The O2 sensor, as tested responds to HC rather than O2.
>   While you might be able to change things, or define other operating modes,
> I know that if I mount the sensor far enough away from the engine that being
> heated is neseccary, then I know what gases matter, and thus what the sensor
> is seeing.
> Grumpy
> 

I think your right on here, I've two observations that run the same
course.

a. A engine temperature based, o2 sensor output correction table in
ecm's.

b. 2.8l/3.1l f-body's, that get real bad fuel mileage in cold (<50f),
wet
weather. The o2 sensor is mounted low, at the 'y' pipe joint, about
one-and-a-half feet from the head exhaust port. (one wire, it cools
off).

I want to confirm this one with a scanner, once the weather gets cold
again, then try a heated sensor, if so.

BobR.


> > Varying the amounts of HC, CO,
> > >CO2, and NOx don't affect the sensor. Only O2 quantity in relation to
> > >the sensor's reference changes voltage.  TPS senses TP whether output
> > >voltage increases or decreases with increased throttle angle.  Why do
> > >you think an "inverted" output from the O2 sensor makes it a Not O2
> > >sensor?
> >     A TPS has a supply voltage that can be modulated in either increasing
> or
> > decreasing fashion with increasing throttle angle, but the O2 sensor has
> to
> > make its own voltage.  My simple logic led me to the conclusion that the
> > compound that is being actually being sensed must be the one that provides
> > this positive voltage.
> > Then I remembered that the O2 sensor is actually a differential sensor,
> like
> > you said: it provides voltage based on the differential between the
> outside
> > reference air and the gases in the exhaust.  So my new hypothesis is that
> > the sensor is sensing O2, but it actually produces voltage from the
> > reference oxygen; when it is compared to an oxygen-poor environment in an
> > exhaust stream, there is a voltage differential across the ion-sensing
> > electrodes, and the voltage produced at the reference side goes up the
> > signal wire.  When the O2 is even on both sides, no voltage is produced.
> >     Of course, this would only apply to the zirconium type O2 sensors, the
> > titanium dioxide ones do actually use a reference voltage and act as a
> > variable resistor.
> >     So now what I want to see is someone test a sensor using sealed
> chambers
> > for both reference and exhaust sides, using O2, HCs, an inert gas such as
> > argon, and another gas containing negative ions (maybe one of the
> halogens)
> > as a control. :-p
> > Soren