[DML] Second part of fuel addivives & efficiency message

["RYERSON,TERRI" <tryerson@xxxx>]

Second part of Fuel additives & Efficiency message.

Additional factors such as combustion heat loss to the cooling system,
frictional losses from rotating and reciprocating parts, and the losses
sustained merely pumping the fuel / air mixture into and the exhaust out
of the engine make the efficiency even worse than Carnots law would
predict.

Current implementations of internal combustion engines and, believe it or
not, those that have existed for many years are already very close to the
theoretical maximum efficiency. Only very slight gains in actual
efficiency through computer fuel injection and ignition systems have been
realized.

How then is it that cars get better fuel mileage today than thirty years
ago? The answer is simple: gains in fuel economy have NOT been realized
through higher efficiency of the engines. Rather they have been achieved
through:

Radial Tires: lower rolling resistance.
Higher coolant temperatures: less combustion heat loss to the cooling
water.
Streamlining the body: lower air resistance.
Smaller cars: lower weight needs less power ( fuel ) to accelerate. This
results in lower losses when the car is stopped. Stopping a car wastes
fuel by transferring energy into heat in the brakes.

These are the reasons that all of these super carburetors and fuel
additives cannot increase the efficiency of existing engines.

Another area of interest is with regard to the loss of efficiency that is
caused by catalytic converters. This area is a very small loss in
efficiency compared to the others mentioned above. This is because the
catalytic
converter and the exhaust system as a whole contributes to losses only
through back pressure. Higher back pressure results in more energy being
wasted pumping the exhaust out of the engine. Unfortunately, contrary to
common belief, this loss is very small. The pressure in the exhaust port
of an operating engine is quite low, much less that one pound per square
inch. A catalytic converter is basically a straight through pipe, that
contains
a sheet of something like asbestos ( may even BE asbestos ) that has been
loaded with a Platinum powder. A VERY small amount of it I might add. As
such the converter contributes very little to back pressure and hence very
little penalty to efficiency.

A much bigger contributor to loss of efficiency due to the exhaust system
is the system itself. The muffler is the biggest loss, followed by bends
and
twists in the exhaust pipe. Bends and twists increase backpressure a lot.
Another factor is the basic internal size of the exhaust system: a bigger
internal diameter pipe has lower losses. Eliminating the muffler, getting
rid of all the bends and twists, and increasing the internal diameter
provides a fairly large increase in fuel economy. Indeed if one looks the
exhaust system in a racing car it is possible to see all these features in
place.

In the end analysis there is no free lunch.

Regards,

George Ryerson
Yellow '83 DMC
DbPgmr@xxxx