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Originally Posted by AndrewJ
Still, I'm having a hard time convincing myself that the air sensor(s) are only going to count the air that's passing through one way (into the engine). I can't help but think it'll end up enriching the mix by "re-counting" the air that has been ejected back from the engine, and re-injecting the fuel for said amount of air.
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So I've done a bit of thought on that... Actually, that's what most of my thoughts focused on as that's arguably one of the key sensors for fuel trim that will be affected.... The conclusion I came to, for a MAF sensor, is that it will not be a problem.
So MAF sensors operate VIA the use of a heater wire (typically). Bulk flow over the wire cools it in a predictable manner. As long as the manifold vacuum is negative - there will always be positive (into engine) bulk flow. The degree of which depends on engine speed and pressure.
In my thought experiment - pressure is what will change. Rather than the typical 22" Hg (or so) - I think there will be slightly higher pressure which in turn results in less bulk flow. WHICH makes sense as we're rejecting a portion of flow per intake stroke.
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Is any of this worthy of Grant Writing? Call me crazy, but someone might pony up a few bucks for the sake of engine research.
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That doesn't sound like a bad idea actually.... I'll stay by what I had said before about my timetable (school for me, right now, takes up all my time - despite that it also takes all my money too
). But someone else should totally go for it if they have the means
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Any word on the emissions profile as well?
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No clue - that's one thing I don't even know where to begin on how to think about it
Intuitively, I imagine that the engine management will compensate for the lower airflow (MAF) in addition to normal a/f metering (O2 sensor). I would think that exhaust temperature change would stay nominal BUT I'm not sure. Given the lower compression and longer power stroke (compared to compression stroke) - the rejection cycle might have lower temperatures (better for NOx?). Exhaust content has been a voodoo type subject for me... I personally would build it, then measure
Turtle
