How is incomplete combustion of fuels in automobiles recognized?I'm doubtful if it's using CO2 or SO2?

Question

Please help me.I'm taking AIEEE exam on 27th of April. Can anyone give me any tips to excel?

Thanks in advance to all the kind hearts that help

Answer 1

The computer measures the amount of air flowing into the engine via the MAF, the mass air flow sensor, and calculates how much fuel is need to combust fully with it, also taking lots of other parameters into account, like engine temperature, speed, etc., and injects that amount of fuel into the cylinders.

There are two oxygen sensors in the exhaust stream, one on each side of the catalytic converter. They tell the computer how much oxygen is in the exhaust. I believe some is needed so that the  catalytic converter will function properly.

So if I have this correctly, the engine always runs with a small excess of osygen, which is used to combust any leftovers, in the catalytic converter.