Why is carnot engine not 100% efficient though no loss of kinetic energy is involved?

BECAUSE THE CONVERSION OF HEAT ENERGY TO MECHANICAL ENERGY IS A NON SPONTANEOUS PROCESS BECAUSE IN THIS ENNTROPY OF THE SYSTEM DECREASES.

FROM FORMULA EFFECIENCY=(1-T₂/T₁) X 100 %   CLEARLY FROM THE FORMULA WE CAN SEE THAT THE VALUE OF T₂/T₁ CANT BE ZERO THEREFORE THERE IS NO MECHANISM WHICH CAN GIVE 100% EFFICIENCY 

Hey even in Ideal conversion of heat to work does not give 100% efficiency..Because heat is low grade energy and you are converting low grade energy to high grade one ..soo you need to pay for that...that''s why it''s not possible...Carnot is jst an ideal approach of converting heat in to work that''s it