On 28 Nov 2006 13:08:05 -0800, in message
om
"max camirand" wrote:

Matt:

I'm too young to remember the seventies. Can you point me towards a
link that explains what you're talking about, with regards to reduced
fuel efficiency in cars for marginally better results at the tailpipe?
Sounds interesting.

In the sixties cars ran at fairly high compression ratios thanks to
high octane gasoline spiked with tetra ethyl lead. Lead poisoning was
an issue and the higher temperatures produced at high compression
ratios lead to more oxides of nitrogen in the exhaust, a major
contributor to the photo-chemical smog that plagued Los Angeles and
other places. High compression engines are inherently more efficient
due to the thermodynamics involved.

Besides being dangerous, lead poisons the catalyst in catalytic
converters, so there was a triple whammy when it was removed, lower
octane because other additives had not been fully developed, thus
lower compression, lower compression still to cut NOx, and
inefficiently designed catalytic converter systems. Then came the oil
embargo that drove the price of gas up high enough that North
Americans had to care. The results were much better for smog in Los
Angeles, but there was strong sentiment that everybody was paying a
price that didn't make much difference in most locations.

Given time, automotive engineers and fuel specialists have advanced
the state of the art and current vehicles are both more efficient and
much cleaner than those of the 60s, but it took time to figure it out,
and not much attention was given to the problem until government
regulations required it. The result was a few years of absolutely
dismal fuel economy in the seventies.

Ryk