中文摘要：

为了解决大型运载火箭液体发动机启动过程难以建立精确解析模型和难以实现实时在线故障诊断的问题，根据其启动过程的特点，设计了基于定时约束Petri网的故障诊断模型和诊断算法，在MATLAB中建立Simulink仿真模型和GUI仿真界面，验证了模型和算法的正确性和有效性．

英文摘要：

It is difficult to build a precise mathematic model and implement real-time fault diagnosis for the starting process of large liquid propellant rocket engines. According to its characteristics of the starting process, a fault diagnosis model based on Petri net with timing constraints and a fault diagnosis algorithm for the starting process of liquid propellant are proposed and implemented. Its Simulink simulation model and GUI simulation interface are built in MATLAB. Simulation experiments show that the proposed model and algorithm are valid and effective.