船用柴油机缸压在线监测系统开发

Development of Online Cylinder Pressure Monitoring System for Marine Diesel Engines

研制由基于现场可编程门阵列(Field-Programmable Gate Array,FPGA)的数据采集硬件和以NI LabVIEW为开发平台的上位机软件组成的船用柴油机缸压在线监测系统,数据采集硬件通过以太网与上位机相连。该系统在线采集上止点、曲柄转角和各缸气体压力等信号,通过等曲柄转角化、上止点标定和多周期平均等处理,计算平均指示压力、压缩压力、爆发压力、燃烧始点及膨胀压力等气缸压力特征参数和放热率;气缸压力特征参数既可用图表形式单缸显示,也可用柱状图形式多缸对比显示;测试结果通过数据库进行管理,以便于后续进行历史趋势分析。经过柴油机试验,验证该系统满足设计要求,可实现对柴油机运行状况的实时监测。

An online cylinder pressure monitoring system for marine diesel engines is designed and developed. The system features an FPGA-based data acquisition hardware, NI LabVIEW based host computer software, and the Ethernet connection between the data acquisition hardware and the host computer. The system collects data online, covering the top dead center position, the crankshaft angle, and the gas pressure of all the cylinders, and calculates the mean indicated pressure, the compression pressure, the explosion pressure against uniformly separated crankshaft angles and further, the timing of combustion, the expansion pressure and the heat release rate with the top dead center position calibrated and the multi-cycle data measurements averaged. The test results for each cylinder can be individually displayed in a diagram. The parameters of all the cylinders can also be presented together in one bar chart for comparison. A database is designed to manage the data for subsequent historical trend analysis. Validation tests are conducted with a laboratorial diesel engine and it is proved that the developed system can achieve real-time monitoring of diesel engine operation condition satisfactorily and meets the design objective.