Quote:
Originally Posted by BoostAddicted
the only thing heat does is help the oxygen sensor work better. Exhaust gas is general a constant temp as long as no misfires are occurring.
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well im looking for no arguments.. but if your "professional" and your saying exhaust gas temps stay the same i dont believe that.. the more fuel. the hotter the exhaust gets. and vise versa, depending on air concentration around you the car is adjusting its fuel mixture, thus causing elevating or lowering of EX temps. this is only my opinion... im not saying i KNOW this.. but this is what i strongly believe. i could never imagine a cars exhaust staying the same temp at all.[/quote]
sorry wrong again actually a lean mixture can cause higher exhaust temps. For example low octane fuel causing spark knock.
A zirconia 02 sensor produces a voltage from 0 to 1 volt, when it is induced to oxygen.
a titania 02 work similar however the pcm runs 1 volt to the sensor and will the induction of oxygen it creates sort of a variable resistor. Producing a signal from 0 to 1 volt.
However none of this can happen with out heat to help the chemical reaction while oxygen passes by the the sensors core. This information I'm sure is what you misunderstood your instructor say.
That is also why late model o2 sensors have heater built in to help it work faster.
Your also right about the exhaust temp changing as it will as the engine warms up and threw out the different rpm ranges. But the change it not constant, and know way can fuel trim be calculated by it.