发动机缸内压力信号频谱分析及滤波方法的研究

STUDY ON FREQUENCY BAND ANALYSIS AND FILTERING FOR PRESSURE SIGNAL IN ENGINE CYLINDER

对135发动机纯压缩缸内压力两种实测信号和由KIVA2计算的模拟信号的三者频谱对比分析,得到了通道效应干扰在发动机缸内压力频谱中的事实位置及形状,并通过有、无通道效应的两种实测燃烧压力时域信号频谱对比分析得到进一步确认。通过数据频谱分析指出:在处理通道效应干扰信号中,光顺处理没有效果;巴特沃思带阻滤波法具有先天的缺陷。设计了频谱曲线拟和滤波方法对实测的发动机燃烧的缸内压力时域信号进行滤波,具有良好滤除通道效应的效果。

The types of passage effect on the whole frequency band characteristic of the cylinder pressure and its exact generating component are found by contrast analysis of the frequency band characteristics of the two types of measured cylinder pressure signals as well as the simulation cylinder pressure signal calculated by the KIVA2 program for the 135-engine. The results are confirmed further by examining two types of measured combustion cylinder pressures, that is with and without the passage effect, by the same analysis method. It is pointed out that the smoothing process is invalid and the filtering process with Butterworth band block filter is also deficient when they are used to eliminate passage effect signal. A new filtering method designed for fitting frequency band curve is used to filter the passage effect signal with nicer result.