Wide range O2

[Jennifer and Brock Fraser]

>Second thot is that many of us will want to have a UEGO as our only O2
>sensor whilst testing, instead of having two bungs in our collectors
>(geez that sounds disgusting, don't it!  B), so if that is one of your
>goals, we'll need to consider "ordinary EGO emulation", to create/mimic
>the output your ECU is gonna expect; ya know that El Capitan shaped
>curve we've all come to know and 'love'. I don't think this will be at
>all difficult, cuz detecting stoich point on the UEGO is bedrock solid,
>since it's the point where the Ip current is ZERO, but it is something
>to consider.

Garfield (et al),

I have a little sideline item that is on-topic with your above mentioned
idea.  On the $8000 (wide-range) meters made by ECM (Engine Control and
Monitoring), they have a "dummy 02 sensor" output on the back of the box
that is able to be connected to a factory controller expecting a
"switchpoint" type signal.  Unfortunately, their algorithm was less than
genius in that it basically "switched" between 0 and 1 volt.  In other
words, it was binary.  As you might guess, this did a lame job of
simulating a sweeping signal from a real switching O2 sensor.

As another note, we often logged data with this meter and found that data
points that were a tenth of a second apart resulted in an amazing amount of
resolution.  For instance, if you recorded an event of "whacking open" the
throttle, you could see a quite lean period of about .2 seconds with a
factory ECM that represented the "lag time" between the fuel metering
system and the airflow surge...  We used this momentarily "high" AFR to
mark the beginning of the dyno run.

One last thing, I've come into contact with someone who built an interface
for one of these sensors to convert it to a factory-style switchpoint
waveform.  The goal was to run adjustable (but constant, once it was dialed
in) A/F ratios under closed loop with a factory ECM.  They had a trimming
adjustment that would move the simulated "stoich switch point" up and down
with actual A/F ratio.  At this point, all I know is the scope of what they
did.  I have yet to gather HOW they did it with the NGK sensor.  I do know
that they did not use the NGK interface box, so the circuit must have been
homebrew.  The device was used on a university project with an alternative
fuel.

-Brock