This course is a core course for students majoring in automobile maintenance and testing as well as related fields. It aims to cultivate students' mastery of basic theoretical knowledge of automotive engine mechanical systems. The course content covers various aspects such as engine structure, working principles, fault diagnosis and troubleshooting, enabling students to comprehensively understand and master the core knowledge and skills of automotive engine mechanical systems. The course content is mainly divided into four parts: (1) Engine types and characteristics (2) Basic engine terminology (3) Introduction to the main structure of the engine (4) Introduction to other systems