Exhaust noise signal of a truck engine is processed. The random noise signal independent of rotational speed is removed from the signal series by short-time self-correlation analysis after frame processing. Then, the time-frequency energy distribution diagram of the signal series is obtained by using short-time Fourier transform. Based on the instantaneous frequency speed extraction algorithm, the instantaneous frequency of the engine is estimated with the help of the improved spectral peak searching method, the speed of the engine is calculated and the corresponding curve is plotted. Based on the information of the rotation speed of the engine, the exhaust noise signal is equally spaced according to the speed and the spectrum array chart analysis is carried out. The relationship between the exhaust noise and the rotational speed is determined. According to the results, the main order information, the sensitive frequency and the sensitive speed are analyzed and obtained. The exhaust noise analysis based on instantaneous frequency estimation algorithm is realized, which provides a theoretical reference for the design and optimization of exhaust systems.%对某卡车发动机排气噪声信号分帧处理,由短时自相关分析得到去除非转速相关随机噪声的信号序列,对该序列进行短时傅里叶变换得出时间-频率能量分布图;基于瞬时频率转速提取算法,利用改进谱峰值搜索法估计发动机瞬时频率进而得到转速曲线.利用该转速信息对原发动机排气噪声信号按等转速间隔切片进行谱阵图分析,确定发动机排气噪声与转速之间的对应关系,分析出主要阶次信息、敏感频率和转速,实现了基于瞬时频率估计转速提取算法的排气噪声分析,为排气系统的设计与优化提供理论参考.
展开▼
