EL-Wakil和Curzon-Ahlborn导出了内可逆卡诺热机的效率界限ηcA,严子浚导出了其最佳功率P、效率η关系(见图1中曲线1)。实际热机为不可逆循环,除热阻外,还存在其它很多不可逆性。一些文献采用一常系数项表征除热阻外的内不可逆性,得到不可逆热机的P-η关系(见图1中曲线2),本文研究表明,这种不可逆热机模型与实际热机特性不符。采用Bejan和Swanson的外热阻加内热漏不可逆定 EL-Wakil and Curzon-Ahlborn derived the efficiency limit ηcA of the endoreversible Carnot engine, and Yan Zi-jun derived its optimum power P and efficiency η (see curve 1 in Fig. 1). The actual heat is irreversible cycle, in addition to thermal resistance, there are many other irreversible. Some papers use a constant coefficient to characterize the irreversibility of internal resistance except for the thermal resistance, and obtain the P-η relationship of the irreversible heat engine (see curve 1 in Fig. 1). This study shows that this irreversible heat engine model does not accord with the actual heat engine characteristics. Bejan and Swanson external heat resistance plus heat leak irreversible