IMM wrote:


Because there have been minor improvements in a flawed highly inefficient
piston engine design over the past 30 years, you appear to think this
exonerates the internal combustion engine, or it is efficient or clean or
something. It is NOT.

The engine it at the end of its lifespan, it should have gone 50 years ago.

snip



As I mentioned in another post, according to MIT the fuel cell is not viable
yet for vehicles, which are the world's worst polluters.

Far more efficient Rotary and Stirling diesel and petrol units appear the
best options to fill the gap. The Stirling is external combustion, which is
much a clean on the burn. Even the Rev Tec Aussie engine, a piston engine,
improves thermal efficiency from 25% to over 50%.


What you have failed to realise, is that even these are only stopgaps too.

At the very best, a fuel BURNING engine delivers only 60%

efficiency - maybe a little more. The rest is waste heat.


If you had goine to a snotty uni, where the theory is taught, you would
understand that any heat engine - and all the above are heat engines -
has its efficiency dictated by the ratio of the temperature of burn to
the echaust temperature. Especially as that is why a 'condensing boiler'
is built the way it is.

The big picture is about energy conservation, especially in terms of
waste heat, and the irreversible (in the short to medium term) problem
if taking fossilised carbon out of the ground and pumping it into the air.

To solve that you need to

- use less.
- burn plants you grew last year.
- generate power by means that don't generate waste heat OR
- use waste heat to replace the use of fuel elsewhere (CHP)

Use of the engines described does not solve any of these apart from, in
a minor way, the first.

Fuel cells can solve many of the above, but in the end. electricity is
bets because it generates very little waste heat when used to generate
mechanial motion.

The issues then become how to generate electricity without using fossil
fuel and/or heat engines. Feul cells are not heat engines, but usually
use fossil fuel. Nuclear power doesn't use fossil fuel, but does use a
heat engine. windmills do neither, but are ugly, of variable power, and
woefully inefficient in terms of space used. Water and wave power does
neither, but is localised as to its applicability. solar cells are even
ore woefully inneficient, but there mat be better technology coming..
burning domestc rubbish and biomass is good as it doesn't use (much)
fossil fuel - i.,e. it's more or less carbon neutral, but it does tend
to need treatement to reduce pollution of toxic flue gasses.

There is no easy answer. But simply slightly better heat engines
burining fossil fuils are almost the worst of all possible answers.