This paper derives the relations between optimal efficiency and power
output of Carnot engines with heat transfer laws of q proportional to
(Delta T-1) and q proportional to (Delta T)(n). The bounds of efficien
cy at maximum power output are also given. The results, which are diff
erent from those based on Newton's law q proportional to Delta T, invo
lve some which have previously been presented. Published by Elsevier S
cience Ltd.