基于倒频谱方法的柴油机气缸压力识别

Identification of cylinder pressure of diesel engine based on the cepstral analysis

分析了柴油机缸盖系统的激励源和其振动响应特性,把缸盖系统看作一个多输入单输出的线性系统,对测试的柴油机缸盖振动信号时域加窗截取对于气缸压力的那一段响应信号,去除邻缸的干扰和其它不相关的激励力的影响,通过低通滤波,消除高频噪声,对压力信号和振动信号进行倒频谱分析,利用求出的传递函数重构气缸压力,结果表明,恢复出来的压力信号和实测信号十分接近,该方法为柴油机的实时在线控制、监测和故障诊断有重要的应用价值。

The characteristic of the excitation and vibration response of cylinder cover are analyzed. The cylinder cover system is regarded as a multi-input/single-output linear system. It is proposed to intercept the acceleration signal due to the combustion pressure using time domain windows, remove the effect of other cylinders＇ disturbing,and remove high frequency noise using a low-pass filter, then the cepstral analysis is carried out for the signals of pressure and vibration in order to get the transfer function recovering cylinder pressure. The result shows that the recovered pressure is close to the raw signal, This method is valuable for real-time controlling, condition monitoring and faults diagnosis of the diesel engine.