Where do you get the idea that I said any of that?dannobee wrote: ↑Wed May 31, 2023 9:54 am I stick by my statement; EGR is inert, it has no affect on the amount of oxygen in the exhaust. Look no further than your 5 gas exhaust analyzer. With the probe out of the exhaust, 20.7% oxygen, with the probe inside the exhaust, 0.3% oxygen. Where is this "other" oxygen of which you speak coming from? Hint, it's simply not there.
With respect to "Hot O2," you do realize that EGR COOLS the combustion process, right? Because the main purpose of EGR is to reduce oxides of nitrogen emissions formed by high combustion temperatures. Ideal gas laws (Charles's Law, to be exact) are not germane to this discussion.
And if you somehow think that disconnecting the EGR valve from a properly running system would increase mileage, you lack the basic understanding of pumping losses and the effect of introducing an inert gas into the intake charge of an engine. Conduct the experiment for yourself. Go disconnect the EGR system on your daily driver and compare the mileage before and after.
Diesel EGR is entirely different because Diesels don't require a homogeneous fuel air mixture for the flame front. And where is the oxygen sensor on a Diesel?
I told you I already understood why it doesnt' change the O2 sensor reading, And my theory was that adding EGR would INCREASE fuel efficiency by reducing pumping losses at low throttle.