卡诺热机[2]是一个依卡诺循环运作的虚拟引擎，其基本架构是由尼古拉·卡诺在1824年建立，在1834年时埃米尔·克拉佩龙扩充了卡诺热机的概念，在1857及1866年提出熵的概念时，鲁道夫·克劳修斯也对卡诺热机进行数学的阐述。
每一个热力学系统都有其特定的状态，当一系统在几个不同的状态之间变化，最后回到原来的初始状态时，就产生了热力学循环。热机的特性是在热力学循环的过程中，系统会对外界作功。
参考资料
- ↑ Figure 1 in Carnot (1824, p. 17) and Carnot (1890, p. 63). In the diagram, the diameter of the vessel is large enough to bridge the space between the two bodies, but in the model, the vessel is never in contact with both bodies simultaneously. Also, the diagram shows an unlabeled axial rod attached to the outside of the piston.
- ↑ In French, Carnot uses machine à feu, which Thurston translates as heat-engine or steam-engine. In a footnote, Carnot distinguishes the steam-engine (machine à vapeur) from the heat-engine in general. (Carnot, 1824, p. 5 and Carnot, 1890, p. 43)