thermocouples and mixture.

[John Werner x25054]

>>>>> "jc" == john carroll <jac at wave.sheridan.wy.us> writes:

    jc> It seems that watching the temperature across the converter
    jc> with a pair of thermocouples would be the best way to make use
    jc> of exhaust gas temperature to monitor mixture.  If it works,
    jc> it has the elegance of causing something that does not
    jc> contribute to performance become useful.

I would think you really would want to monitor the temperature where
you can more quickly detect a change.  The problem I see is that the
large thermal mass of the catalyst would change temperature too slowly
to use to quickly adjust the mixture.  I would be afraid of the
exhaust temperatures rising suddenly (too lean) and burning a valve
before the cat showed much change (due to the new mixture).

A better approach, IMHO, would be to monitor on the exhaust manifold,
or even in the exhaust stream itself.  Perhaps a needle like thermal
couple probe inserted into a hole in the exhaust manifold would work.

BTW: I remember reading somewhere that Volvo looked into a fuel
control system based off of exhaust temperature instead of Ox sensors.

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