Introduction & O2 Sensor Questions

[James Boughton]

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Well I see Fred also receives "the attachment" :-)  I see it says =
something about eudora.  I don't use eudora so I am wondering if this is =
on your machine?
=09

>Have you thought about looking at the resistance of the built in heater =
element.
>I put an amp meter on mine once and could see the current drop as the =
sensor got
>hotter.(have an egt gauge too)

Yes, I looked at the resistance of the heater, but it was fairly slow to =
respond and only changed from 6 ohms to around 12 ohms which I was =
concerned about trying to measure since changes in lengths of the leads =
could have a large effect on the output.

>I thought I heard though that the accepted way to measure the temp was =
via
>the sensor's
>output impedance. I've got info somewhere on a O2 interface chip that =
looks
>at output
>impedance to determine when the sensor is warmed up enough to go on =
line.

>Fred

Yes, I suppose you could check the impedence of the sensor, but the main =
point of measuring temperature is to improve accuracy as opposed to =
determine the sensors readiness.  If you look at the Nernst equation it =
is linear with temperature.  Also, according to Heywood the exhaust gas =
oxygen partial pressure is also a function of temperature (above and =
beyond the function that is associated with the sensor output).  All I =
can say is I hope it works :-)  It has to be more accurate than a =
standard oxygen sensor.

>> Actually, I am working on a temperature compensated oxygen sensor for
fuel/air measurement in the rich region.  Getting the oxygen sensor with =
a
built in thermocouple has been the most difficult part.  I am curious =
why
you didn't suggest a thermocouple for temperature measurement?  It seems =
the
best method to me, but I've been wrong many times before:-).
>>
>>Jim Boughton
>>boughton at bignet.net
>>
>>Attachment Converted: C:\EUDORA\ATTACHME\REIntro2
>>

Jim Boughton - again!

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