"Rich Grise" wrote in message
news
On Mon, 13 Feb 2006 18:03:39 -0500, Ed Huntress wrote:
"carneyke" wrote in message
oups.com...
I think my point is for everything we do there
will always be a "bad" side and its a shame it gets so political. So
please accept my appollogy for being rude and as Jim wrote "Ignorant".
Sorry Jim.....

Gee, you must be coming from an awfully polite newsgroup. g

FWIW, most of the fuel you burn in your car goes out the tailpipe. A
super-efficient spark-ignition engine turns something like 24% of its
fuel
into motive power (if my memory of this number is not accurate, someone
please correct me; I haven't looked it up for years). Of that, something
like 60% makes it to the drive wheels. So a spark-ignition-engined car,
on a
good day, delivers somewhere around 15% of the thermal potential of the
fuel, as motive power to the wheels.

It doesn't get a lot better with other engine types. A large, efficient,
stationary diesel is good for something like 28% at the shaft. The
number is
similar for a huge, stationary, multi-stage steam turbine. And, believe
it
or not, also for a Stirling, running with helium or hydrogen for a
working
fluid, at very high internal gas pressure and with a high-efficiency
heat
exchanger at each end.

Sucks, doesn't it? And that's on a good day. d8-)

Speaking of losing memory neurons, I seem to recall seeing a sort of
diagram, back in the '50's, when they had flat-head straight 6's, that
something like 2% of the potential power in the fuel actually got to the
wheels.

Ha! Well, they may have exaggerated that a bit g, but the percentage is
very low. Flatheads were pretty awful from a thermal-efficiency
standpoint -- too much combustion-chamber surface area relative to
combustion-chamber volume.

There were HUGE thermal losses, and friction, and yadda yadda yadda...

Yeah, sometimes you have to wonder how they go anywhere at all. d8-)

Compare that with a hydrogen fuel cell: up to 80% or so, without fancy
cogeneration. The electric motor it powers also is around 80% efficient, for
something like 64% overall efficiency.

Unfortunately, producing the hydrogen is not that efficient. No free lunch,
once again.

--
Ed Huntress