[Diy_efi] Fw: wide-band O2 sensor comparison

[Bruce]

I sent **my** used, and abused DIY-WB (your results may vary) to someone
that actually works with emission equipment for a living.   The sensor used
has 10K miles on it, and a couple periods of short term use unheated.
About the normal life of one used by an average guy.
   For a $20 controller, WTH, looks good to me.
   Like I have said from the beginning, not a Lab grade devise, and for the
average mechanic just wanting to get close, it works for me.
   Rather then edit the original letter, I'll let the reader go to the
DIY-WB.COM page and get the corresponding conversions, and draw their own
conclusions.   I did include the PS which was from a second letter.
   In case you haven't heard of the ETAS unit, it's what firm's like Ford
Motor Co use in their work.
   Bruce






> I tested Bruce Plecan's wide band oxygen sensor* today, back-to-back
> with a commercially available unit made by ETAS.  My impression is
> that Bruce's sensor is quite good, although I was not able to test
> under a wide range of conditions.
>
> I mounted Bruce's sensor at the tailpipe, in a fitting he provided.
> I used wads of aluminum foil to seal between the truck's large
> diameter tailpipe and the pipe that Bruce supplied, to minimize
> leaks.  Unfortunately the commercial ETAS sensor was not next to
> Bruce's; it was mounted near the engine, upstream of the catalytic
> converters.  However I only expect the catalytic converters to have
> a significant effect near stoichiometry (about 14.6 air/fuel ratio).
>
> I took data from both sensors while changing air/fuel ratio.  I did
> this at two different conditions: idle in neutral, and while brake
> torquing to about 1200 RPM (brake torquing is revving the engine
> with automatic transmission in drive and one foot firmly on the
> brakes).  I couldn't drive the vehicle with the sensor mounted,
> because of the wire going from the tailpipe to the cab of the truck
> (there was nowhere to support the wire).
>
> The readings at the two conditions agreed within less than half an
> air/fuel ratio.  I would expect Bruce's sensor to be even more
> repeatable if mounted closer to the engine (further from the
> tailpipe and possible leakage).
>
> Here's the data (A/F from commercial ETAS followed by voltage from
> Bruce's wide-band oxygen sensor).
>
> Idle in neutral:
> ETAS WB-O2
> 11.05 1.6
> 12.05 1.95
> 13.1 2.26
> 13.5 2.35
> 14.6 2.48
> 16.1 2.63
>
> Brake torque to ~1200 RPM:
> ETAS WB-O2
> 11.05 1.58
> 12.0 1.86
> 13.0 2.16
> 13.45 2.29
> 14.55 2.46
> 15.75 2.58
>
> Bruce, the above data is from sensor number 9513 (the cleaner one).
> Sensor number 7609, the blackened one, gave similar readings except
> that between 13 and 14.6 A/F it showed very large fluctuations.

P.S. Bruce, please post the A/F vs voltage calibration that you have
been using.  Your LED indicator seemed to be in good agreement with
the commercial ETAS, so the calibration must be close.






_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi