Abstract: The pneumatic braking system of heavy commercial vehicles is a safety item in the whole vehicle, and its characteristics under certain conditions are sometimes easily overlooked by designers. Therefore, this paper takes the pneumatic braking system as the research object, analyzes the stress of internal components of the four-circuit protection valve when the residual pressure of each air storage chamber is different due to various reasons, and observes the corresponding relationship between inflation pressure and time through basic air pressure test. The final result shows that the pneumatic braking system with four-circuit protection valve is obviously different from the ordinary pneumatic braking system in certain conditions: the smaller the residual air pressure, the less easy it is to inflate, but the larger the residual air pressure, the higher the inflation priority. It is hoped that the research results of this article can bring some enlightenment to designers to avoid the occurrence of problems related to pneumatic braking.

Key words: Commercial vehicles; Brake air chamber; Pressure sensor; Four-circuit protection valve

摘要： 重型商用车的气制动系统在整车中属于安全项，其特定条件下的特性有时容易被设计 者忽视。文章以气制动系统为研究对象，通过基本的计算分析当车辆因各种原因导致各储气 室残压存在差异时，四回路保护阀内部元器件的受力，以及通过基本的气压测试试验，观察 各储气室残压存在差异时充气压力与时间的对应关系。结果表明，带有四回路保护阀的气制 动系统与普通的气制动系统在特定条件下充气特性明显不同：残留气压越小的储气室越不容 易充气，反而残留气压越大的储气室充气优先。希望文章的研究结果能给设计者带来一定的 启示，以避免气制动相关问题的发生。

关键词: 商用车；制动气室；压力传感器；四回路保护阀