基于缸盖振动信号分析的柴油机失火故障检测

Misfire Detection of Diesel Engine Based on Analysis of Cylinder Head Vibration Signal

用小波软阈值降噪的方法提高了柴油机缸盖振动信号的信噪比。对降噪后的振动信号进行了功率谱分 析,通过比较单缸断油前后功率谱的变化,找到了缸盖燃烧冲击振动的频段。以频段内振动信号的能量与总能量 的比值为诊断参数,识别了柴油机的失火故障。用实测数据证明了该方法的有效性。

Signal-to-noise ratio of cylinder head vibration signal was enhanced by using wavelet's soft threshold value de-noising method. Power spectrum analysis was applied to the de-noised vibration signal. Power spectrum of normal operation and the one of one-cylinder-oil-break operation was compared. The frequency range of cylinder head vibration, which was caused by combustion, was found out. The ratio of the energy of the above-mentioned frequency range to the total energy of the de-noised vibration signal was utilized as a fault diagnosis parameter, and misfire malfunction was identified by it. Real measurement data shows the capability of the proposed methods.