Hi all. I need to focus on the operation of the oxygene sensor, and I don't mean the wideband sensors. I wonder if it's possible to see a tendancy of an engine begin to run lean by monitoring the oxygene sensor output? Even if the engine runs in closed loop and the sensor output walks up and down according to the fuel regulation, would I see the times when the output signal is low (lean) increase relative to the times the signal is high (rich)? Or could I put it this way. If the oxygene sensor output is only 10% of the period high and 90% low, could this indicate that engine is running lean? Or the same around if the output is high 90% of the period and 10% low, could this indicate a rich run? Thanks,
Oxygene sensor behaviour during rich and lean run
Oct 14, 2011
6 Replies
Nope, they're not at all linear & if it's switching then it's essentially running right. What makes you think it's wrong?
Is there any way to determine "where" in the fuel trim area the engine runs for the moment, by just looking at the sensor output signal? If something made the mixture lean and the ecu had to walk all the way up to its maximum fuel trim, would there be no different behaviour on the oxygene sensor output? When the ecu hits the maximum fuel trim value, and still doesn't get a rich reading from the sensor, a fault code will probably be set aswell right?
Look, I just want to get in deep with closed loop operation, I have no problem with my car. Thanks!
Regards TF
You need to look at the STFT and LTFT's; not so much the actual lambda values...
Tim.
This is mainly about wideband, but explains narrow band too.
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Not accurately,
No, once it's at trim then it'll be about 50%, if you want to know how far it's trimmed then you nead an ECU reader
Yes
Oxygene was a brilliant album by Jean Michel Jarre so perhaps you mean Oxygen? :-)
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