【摘要】 通过比较发动机原理教材中四冲程柴油机换气过程中排气过程表述的异同，指出现有教材中常见的错误，这些错误会给学生和其他读者学习理解造成困惑。作者和编辑应以更严谨的态度编写和出版教材，即使是对经典的插图，也要以审慎的态度仔细审读，以避免图文矛盾和内容错误。也希望相关教材中的错误能得到及时修正，方便学生和读者学习。更多还原

【Abstract】 In several general textbooks of engine principle,some important differences are found in the exhaust process of four-stroke engine.The descriptions and diagrams are different in different textbooks,and some of them are wrong that will make difficult to understand for students and other readers.Authors and publishers should pay special attention to the correctness and rigor of textbooks and improve the quality of textbooks.更多还原