Quote:
Originally Posted by Daox
Interesting idea, but unless I'm missing something, I don't think that this will be a problem either. If the exhaust gas is coming out the engine rich, it will recycle some of that rich exhaust gas, but the rest of the rich exhaust gas will still get to the O2 sensor and it will trim the fuel injectors back until it hits a slightly lean condition, then back again as it normally would with a narrow band sensor setup.
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What I was suggesting, and I don't know for sure if it would work this way:
If the EGR pulls exhaust gasses from after the first O2 sensor (between O2-1 and the cat) it would be pulling in gasses that had already been metered by the O2 sensor, and reintroducing them to the combustion chamber without having been metered by the intake sensors, so now you've got gasses in the combustion chamber (including whatever oxygen was left over in the exhaust gasses) that haven't been compensated for by the intake sensors, that are going to pass the O2 sensor again.
Although it does seem like the O2 sensor should richen the mixture slightly and burn off that O2 that was left over, so it wouldn't pass the sensor again. So maybe it won't be a problem.
Guess I should have worked the path out in my head a little more before posting, eh?
Also, you're correct about turbulence in the combustion chamber - you wouldn't really be able to ensure that it all stayed at the bottom unless it was injected there. Of course, the unburned HC's flowing back into the combustion chamber should help with the stratification of the "normal" intake by providing some "bridging" between the fuel/air molecules of burnable material.
Only experimentation will yield results, though.