Engine Cycles

发动机循环

For a constant mass of gas, the operation of a heat engine is a repeating cycle and its PV diagram will be a closed figure. The idea of an engine cycle is illustrated below for one of the simplest kinds of cycles. If the cycle is operated clockwise on the diagram, the engine uses heat to do net work. If operated counterclockwise, it uses work to transport heat and is therefore acting as a refrigerator or a heat pump.

对于质量恒定的气体，热机的运作是一个重复的循环，其PV图将是一个封闭的图形。下图展示了其中一种最简单的循环示意图。如果循环在图上是顺时针进行的，热机将利用热量做净功。如果逆时针进行，则利用功来传输热量，因此它起到制冷机或热泵的作用。