oder, check your "facts". what you report is so far from what happened at the
time we can onl assume your parents were still in grade school, or that you
personally learned to read just last year.
(modervador)
Date: 9/30/2004 1:26 PM Eastern Daylight Time
Message-id:
What I know is that what you say and what is true are often opposites,
and that you sometimes can't read or count backwards from 1961 to
1960.
What I'll say now is that I was addressing the question on the
reasoning behind oxygenated gasoline. I do claim that it exists
especially because of carbed engines initially, which I expanded upon
to show how non-carbed engines also benefit. I never implied that the
EPA accomodated car manufacturers on this issue, generally the
opposite was true. The winter RFG (reformulated gasoline) program went
into effect 1995, a year or two after the last carburetted new truck
was sold in the US and 2 or 3 years after the last car. Plenty of
carb'ed cars were on the road in big cities then, less now, but the
program continues because of benefits even to fuel-injected vehicles.
As for the CVCC, few if any gasoline engines got better mileage in
comparable vehicles and it was listed by the EPA as #1 for 1977. It
"sold poorer" (your words) even at the same time it was the only Honda
car engine available in U.S. in the early 1980s, when Honda was
expanding production and making great increases in car sales in the
US. But you knew that, didn't you?
What you don't know, or at least you haven't said correctly, is the
history of automotive technology and the formulation of gasoline.
%mod%
(JAXAshby) wrote in message
...
oder, they got poorer fuel mileage than catalytic converter engines, but
you
knew that didn't you? they also sold poorer partly because of their poor
fuel
mileage and more so because they were maintenance hogs. but you knew that,
didn't you?
are you *still* claiming that oxygenated gasoline exists because those
carb'd
engine -- few in number -- needed special fuel upon warm up, AND the EPA
wanted
to accomodate the car manufacturers?
yeah, sure. whatever you say.
(modervador)
Date: 9/29/2004 11:07 AM Eastern Daylight Time
Message-id:
(JAXAshby) wrote in message
...
Reduction of CO emissions during warm-up for carbureted engines.
mum mum vador, knock it off. for all practical purposes there are no
carbueted
auto engines on the road for a very long time. I believe that last such
sold
as new was the miserable CVCC engine, and that was well more than 25
years
ago.
The carburetted CVCC engine's last year was 1985. By 1984 it was
running closed-loop with feedback from an O2 sensor in the exhaust
stream to maintain a stoichiometric mixture, so the "lean burning
stratified charge" feature of the original CVCC was no longer being
used although the head retained the pre-combustion chamber and carb
retained the auxilliary 3rd barrel to feed the prechamber. The
prechamber and 3rd barrel were done away with for 1986. The last year
for the standard carbed Accord engine was 1989 (injection was an
option starting in 1985) and the Civic models all got fuel injection
in 1988 I think.
But that's just the Hondas. There were plenty of other carbed engines
made which are still around, both open-loop and closed-loop, and I
don't care to dredge to find when the last one was sold new in the
U.S., but it was more like 14 years ago and it likely wasn't a Honda.
There are also open-loop fuel injection systems (no O2 sensor).
With open loop, before the engine warms up, combustion is less
controlled and the choke (or idle enrichment in FI) makes it run
slichtly rich, increasing CO output. Even with closed loop, the design
of the O2 sensor and engine management system is a factor. The O2
sensor does not send out a signal till it warms up, so the engine
management system must run in open-loop mode till then, defaulting to
slightly rich with elevated CO output. Many O2 sensors have a heating
element to speed the warm-up of the sensor to decrease the time
running open-loop. But then there's the catalytic converter, the final
link. Till it warms up, it allows the CO to escape unconverted. Some
catalytic converters are being designed to have heaters that decrease
warm-up time.
So even the most modern car has some period after a cold start, during
which it runs open-loop and spews more CO than it does after warm-up.
Oxygenated fuels increase the oxygen-to-hydrocarbon ratio during
open-loop running and thus promote more complete combustion that
produces CO2 rather than CO. In several metropolitan areas there
remains a high proportion of older cars with carbs and early-version
fuel injection systems. In winter months the warm-up time is increased
during which these cars emit increased CO to an extent large enough
that the EPA (or some other branch of gummint) has mandated oxygenated
fuels during the coldest months in these areas.
%mod%
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