[SEL] OT PA trip & fuel costs

[bill at antique-engines.com]

>>and then feeding the engines  increased EGR gasses to
deal with the increased NOx emissions caused by the  higher combustion
temps. <<

Large quench areas are also a cause of NOX. So to reduce NOX emissions,
they had to find a way to minimize quench. do that and you have detonation
issues, melted pistons due to reduced or removed boundry layer, etc. To
offset that, the fastburn chamber was designed.
Like I say, racers have known for years you need higher compression and
faster burn for more power AND effeciency.
Cubic inches=power
higher compression ratio=power but more "ping" so you add quench. Add
turbulance to improve and increase burn rates. Flow the heads for power
and effeciency - todays head designs outflow "muscle car" heads that have
been ported and polished.
People cursed the EGR, but it actually is a good thing for your engine as
far as a longer life on engine pushed hard. I know a couple folks who
actually have resurrected their EGR to reduce ping and squeeze a bit more
"life" out of their engines.

Bill
Runnells, Iowa
Chapman/OWE&PCo. Registry and History
http://antique-engines.com
1970 Javelin (originally about 10:1, now about 9.4:1 with step-dish
pistons for more quench and faster burns)
1982 Eagle SX/4
1980 Eagle wagon
http://theamcpages.com

>
> In a message dated 6/6/2007 4:37:03 P.M. Eastern Daylight Time,
> bill at antique-engines.com writes:
>
> Note on  gas engines, they have INCREASED compression ratios and are using
> fast burn  chambers.
> Remember the compression ratios of the 60's and early 70's were  in the
> 10:1 and 9:1 range, then dropped to 8:1 in the green decades - they  are
> back up.
> Wonder why??
>
>
>
> The major reason compression ratios increased a few years back was that
> the
> EPA was focusing on cold start hydrocarbons.  I forget the exact numbers
> they
> were quoting, but I remember them saying that cars released more raw
> hydrocarbons out the tailpipe in the first few miles (before the catalytic
>  converter
> was lit) than they did in the next 50 miles of driving...or something
> like
> that.  They were looking at all kinds of solutions like heated  catalytic
> converters.  These things had electric heater grids that would  heat them
> to
> operating temps before the driver could start the car.  They  also looked
> at
> hydrocarbon absorbers like the ones Toyota used on their hybrids  for a
> few years.
> Eventually they settled on bumping the compression ratios  to get the cold
> start hydrocarbons in line, and then feeding the engines  increased EGR
> gasses to
> deal with the increased NOx emissions caused by the  higher combustion
> temps.
> Joe Rappa
> Mexico, NY
>
>
>
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