中文摘要：

介绍了适用于工程应用的柴油机气阀漏气声发射便携式监测系统。其中，声发射传感器通过手持式安装座便携式放置在柴油机缸盖，以STM32F103VC微处理器为核心的便携式信号采集控制器远距离控制NI FPGA数据采集卡的高速数据采集，LabVIEW平台下开发的声发射信号分析软件对采集的信号进行预处理后，经过滤波、信号区间提取和EMD信号分析处理，提取气阀漏气特征参数，监测柴油机气阀状态。经某中速机的试验验证，系统能适用于船舶现场工程环境。

英文摘要：

The portable monitoring system for valve leakage based on acoustic emission technology isintroduced, which is suitable for engineering application. An AE sensor can be portably located on the cylinderhead through a portable sensor adapter. A handheld data acquisition controller based on STM32F103VCmicroprocessor is used to remotely control the data acquisition of a high resolution FPGA data acquisitiondevice. A Lab VIEW monitoring software is developed to preprocess, filter, phase extraction, EMD （EmpiricalMode Decomposition） handling, feature parameters extraction and valve condition monitoring. Finally, theapplicability and feasibility of the monitoring system under fieM environments is verified on a medium-speedmarine diesel engine.