RE: RE: EGR systems

From: Pindell, Tim P (TPindell@otterbein.edu)
Date: Tue Jan 08 2008 - 12:26:18 EST


>
> If there is some other horrible aspect of NOx I am waiting to
> be informed.

Nitric acid (in addition to the sulfuric acid from coal burning power
plants) in our waterways and soil. I don't know whether it's "horrible"
like PCBs or dioxin, but I'd still rather minimize it if possible.

> The implication that that the EGR is needed to control
> combustion temps is inane. TOO HOT does not happen at correct
> mixture, it is usually a too lean mixture.

>Running wide open
> throttle with a 12:1 mixture will be a lower EGT number than
> at 16:1.

>
> Under WOT if you go lean you burn down.

I think we're all familiar with the principle.

> I contend the EGR was a solution to a problem that never
> needed to be solved.

Maybe. I contend that if we all lived in filthy little sealed bubbles of
our own making, I wouldn't care what you did, but because >your<
pollutants (whatever they may be, NOx or not) eventually become >our<
pollutants we have a problem.

>
> The hi-po engines of the sixties didn't need it to keep from
> burning down engines.

Because that's not what EGR is for.

>
> NASCAR or NHRA don't seem to use EGRs because guess what,
> they are not a good thing,

Entirely different application. They typically run WOT most of the time
making the EGR system a moot point. Your street EGR system is inactive
at WOT as well.

>
> To defend them is an insult to your own and my intelligence.
>

Can't we have a reasonable discussion without...this?

> My 92 Dak gets about 1-2 mpg better when the EGR is blocked.
> Did you ever notice how your truck seems to run better before
> it is completely warmed up? I know part is the open loop
> before normal temps are reached, but the other is the EGR is
> not on line yet.

Yeah, and your cold-engine, open-loop fuel efficiency is in the crapper
with the result being relatively large amounts of CO and HC in my air as
opposed to what we get under normal operating temperatures. I'd rather
get into closed loop as soon as possible. Do you know what percentage of
increase in open-loop performance is due to the closed EGR valve? Given
that we are in an era where CAFE matters a bunch, 1-2 mpg could be huge,
although without using very precise measuring techniques, probably
within the margin of error for a single vehicle. I'd bet that current
engines can get your 1-2mpg increase (at least) and still run the EGR.
Is the extra 1-2mpg, given that it exists, "worth the trade-off"? I
don't know. There is a probably a lot more going on here.

>
> my Dakota will not pass the NOx standard with the EGR
> blocked, though the HC and CO are almost zero.

That's what the EGR system is there for. I understand your point.
Without the EGR system, you're still getting a good burn on a modern
closed-loop engine (with a whole raft of other gummint mandated gizmos.)
You're probably one of the relative few of us who are conscientious
enough to keep our engines in good repair. That matters as well.

>
> And once again...what does NOx do...generates a brown cloud
> and makes plants grow.

That's rather simplistic don't you think? If that's >all< it did, I
seriously doubt we'd be having this discussion. (Unless you're really
as cynical as Rick.) Soils have different acid buffering capacities,
plants use different amounts of it. I rather doubt that either of us
knows enough chemistry to argue this point very well. I'd prefer we not
screw around with complex natural systems that we don't completely
understand. Unintended consequences and whatnot. Let's be responsible
stewards.

>
> I remember reading and article in Machine Design in 1972...

I shudder to think what vehicles would be like if we kept to the 1972
standards. Carbs for everyone! Technology has advanced somewhat since
the Nixon administration. We have a couple dozen more cars too.

>
> One difference, I have 4 ferrets that agree with me.
>
>
> now lets go after CO2

Agreed. If I absolutely had to make a choice between NOx, CO2 and
fighting 4 ferrets, I'd definitely say "Bring on the brown clouds." I
think highly of our American technicians and engineers. I think they'll
continue to make progress on all fronts.

>
> rob/ferts/phx
>

tim/pups/cmh



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