基于振动信号的柴油机缸内燃烧状态估计方法

Estimation of Combustion Status in Diesel Engine Based on Vibration Signal

利用S变换对柴油机燃烧激励的响应信号进行了时频分析,通过分析找出最能表征各种燃烧状态特征的时频域。据此设计了FIR带通滤波器,并对燃烧激励的响应信号进行滤波,滤波后的信号与缸内燃烧状况有良好的相关性。用这种方法对不同的燃烧状况建立样本库,求取实测信号与样本库中样本的贴近度,可判别缸内的燃烧状况,模拟试验结果验证了该方法的有效性。

The vibration signal generated by combustion in diesel engine can be converted from one-dimensional time domain signal to a two-dimensional time-frequency domain using S-transform and time-frequency domain, which contains richer information of combustion status. A FIR band-pass filter was designed according to the frequency range of the time-frequency domain. The vibration signals generated by combustion in different combustion statuses were passed through the band-pass filter and the filtered signal had well relation with combustion status. A sample bank could be built using the filtered signals. The similar degree between the measured signal and the templates were calculated and the combustion status of the diesel engine was estimated according to the peak magnitude of similar degree. Finally, the simulated results show that the method is feasible.