Mounting o2 sensor. Where in exhaust?

[oldcorollas]

the narrow band sensor is made from Zirconia.
when there is a difference in amount of oxygen from one side to the other, at high temps, it generates a voltage.
that is how narrow bands work.


for wideband, you have two zirconia cells.
one works the same as a narrow band, ie it generates voltage between air and inner side of sensor.

what makes it snazzy is that the second zirconia cell is hooked up backwards.. ie instead of generating a voltage based on oxygen difference, it uses an applied voltage to cause an oxygen difference.
so it actually pumps oxygen into or out of the gap between it and the inner narrow band sensor, to keep the narrow band sensor at stoich.
the voltage/current that is required for the second zirconia cell to pump oxygen to keep the inner sensor at stoich, is what is measured, ie turned into a lambda signal..

that make sense?

[Big rob]

Read this: http://www.megamanual.com/PWC/index.htm