STUDIES OF UNCONVENTIONAL HEAT ENGINE DESIGN, OPERATION AND EFFICIENCY - 4-STEP QUASI-CARNOT CYCLES WITH A LINEAR P V TRANSITION/

Although the ideal Carnot engine rejoices in the largest efficiency of any heat engine operating between given temperature extremes, alterna tive closed-loop four-step cycles in which a variable-temperature, str aight-line transition replaces the Carnot high-temperature isothermal expansion appear ostensibly to offer a higher thermodynamic efficiency . This arises from the fact that higher maximal temperatures are attai ned; the efficiency of the equivalent Carnot engine operating between such temperature extremes reinstates Carnot supremacy by slightly tran scending the unconventional engine's efficiency. Our investigations st ress the importance of the second, as well as the first, law of thermo dynamics, and consider operating characteristics quantitatively for sp ecimen engines of various design.