I understand O2 sensors allow the ECU to know if the engine is running lean by detecting oxygen in the exhaust. Indeed, if the engine is running lean, the ECU can determine how lean based on the magnitude of the O2 sensor signal.
If the air fuel ratio is perfect (stoichiometric) or rich, there theoretically would not be any oxygen in the exhaust for the O2 sensor to detect. So, how the heck does the ECU/O2 sensor distinguish between a little rich and a lot rich, given that both conditions should have little or no O2 in the exhaust?
Sorry for the silly question. It just occurred to me that I don't understand this, even though I've thought I understood O2 sensing for years.
Thanks,
Neil
If the air fuel ratio is perfect (stoichiometric) or rich, there theoretically would not be any oxygen in the exhaust for the O2 sensor to detect. So, how the heck does the ECU/O2 sensor distinguish between a little rich and a lot rich, given that both conditions should have little or no O2 in the exhaust?
Sorry for the silly question. It just occurred to me that I don't understand this, even though I've thought I understood O2 sensing for years.
Thanks,
Neil