I make no claim to knowledge in thermodynamics - but - I think the increase
in efficiency is partly due to the increase in size. Larger objects lose a
lesser amount of heat (energy) than smaller ones. Common steam engines are
also more efficient in the larger sizes.

Bob Swinney
"Karl Townsend" wrote in message
k.net...
I'm curious, they claim a thermal efficiency of 50%, nearly double that of
an automotive diesel. How do they do it? and why can't it be done in the
automotive size engine?

Karl