O2 sensor?

"Gary" wrote in message
ps.com...
On Jul 2, 6:52 pm, "Morgans" wrote:
"Blueskies" wrote

"A friend flying an IO-360 powered Glasair installed an oxygen sensor
system that has an panel mounted indicator light to show when balanced
combustion is reached. He simply adjusts mixture until the light comes
on and knows he has complete combustion (his theory is that EGT is
really just a good guess). He has had very good results from this
system in terms of fuel economy and performance.

How does it deal with the lead fouling issue?

I had always thought that Oxy sensors were only used while the engine
was at
low power settings, and that once it was cranked up to full power, the
engines ran in a closed loop system, ignoring the Oxy sensor. I would
think
a mass airflow sensor, and a programmed controller to set the mixture to
the
ideal settings would be more useful.

I would be interested in seeing how much the mixture was changed, with
the
advice of the Oxy sensor setup.

I have to admit that it does sound interesting.
--
Jim in NC

Jim,
You have it backwards. EFI uses pre-programmed settings until the
engine reaches operating temperature. Then the system enters "closed
loop mode" and uses output from the O2 sensor to provide "fuel trim"
data which offsets the preprogrammed values for minimum emissions.
Some later model cars have electrically heated O2 sensors to allow for
closed loop mode quicker (EPA lower emission requirements).

When used with 100LL the O2 sensor will slowly become contaminated
and cease to work.

Gary also in NC

I have been told that they slow down, but may not cease to work in the
absolute sense. In other works, they will become useless for the closed
loop control that an automotive ECM requires, but might remain quite useable
in the manner that a pilot might use them. As to a comparison between an O2
sensor and EGT, I just don't know; but I am quite curious.

BTW, it is probably usefull to think of the Open Loop Mode of the automotive
ECM at Wide Open Throttle as being analogous to the enrichment valve feature
of an aircraft carburetor. As soom as you no longer tramp the accelerator
firmly to the floor, the ECM will return to best economy (or possibly least
emissions) mixture--at least that is the impression which I received from
the limited litterature I read.

Peter
(Awaiting correction from any with real bench experience.)