"Ignoramus6950" wrote in message
...
I was thinking about electric cars today.

An internal combustion car, burns fuel inside cylinders and produces
energy according to Carnot cycle. Say, it makes 28% of energy from the
total BTU of fuel that it burns.

Compare it with an electric car. A coal electric power station
operates at efficiency of 33% (Wikipedia).

Then 10% of this is lost in power distribution.

More lost in stepping down line voltage to 220 volts.

Further, more is lost in a battery charger.

Then more is lost in the car battery.

Then more heat is lost in motor windings and power semiconductors.

This is probably by far less efficient than internal combustion an
distribution of gasoline!

And how is it going to reduce CO2 emissions, if more CO2 needs to be
burned as coal than would come from gasoline?



As far as cost per mile traveled, there can be no doubt that fully electric
automobiles are extremely economical to operate, and except for energy
that's lost due to heat and friction, they are 100% efficient all the way
from zero clear up to full rated output.

The problem is that the combustion engines that have traditionally been used
in automobiles are only mildly efficient at best when run at peak output, at
conditions other than peak, they are so terribly inefficient that trying to
compare them to a coal or natural gas fired electrical generation plant is
pretty much an absurd notion.

Enter the Atkinson cycle internal combustion engine, and hopefully you'll
start to understand the reason why hybrids are able to be so fuel-efficient
while also being able to perform reasonably well when you put the pedal
down.

http://en.wikipedia.org/wiki/Atkinson_cycle

"While a modified Otto cycle engine using the Atkinson cycle provides good
fuel economy, it is at the expense of a lower power-per-displacement as
compared to a traditional four-stroke engine.[3] If demand for more power is
intermittent, the power of the engine can be supplemented by an electric
motor during times when more power is needed. This forms the basis of an
Atkinson cycle-based hybrid electric drivetrain. These electric motors can
be used independently of, or in combination with, the Atkinson cycle engine,
to provide the most efficient means of producing the desired power. This
drive train first entered production in late 1997 in the Japanese-market
Toyota Prius."