机体振动信号时频特性与燃烧压力相关性分析

Correlation analysis between time-frequency characteristics of vibration signals and combustion pressure

为了探明机体振动信号与缸内燃烧状态间的相关性,本文通过改变转速、转矩、润滑油温度及配缸间隙形成不同的燃烧状态,利用连续小波变换算法得到了振动信号时频域特性,并与燃烧压力峰值进行对比分析。结果表明:随转速增加,燃烧压力峰值出现波动,8 kHz以上成分的能量总体呈增加的趋势;随转矩增加,燃烧压力峰值及振动信号的能量均增加;随润滑油温度升高,20 kHz以上主要频率成分的能量增加;随配缸间隙增加,10kHz以上频率成分的能量总体呈增加的趋势。

In order to investigate the correlation between block vibration signal and combustion status in the cylinder,parameters including engine speed,torque,lubricating oil temperature and piston-liner clearance were changed to form different combustion status.Time-frequency analysis result was contrasted with the peak combustion pressure.Results showed that the peak combustion pressure fluctuated under different engine speed.The energy of frequency components higher than 8 kHz generally increased.The peak combustion pressure and the energy of block vibration signal all increased with the increase of engine torque.The energy of main frequency components above 20 kHz increased with the increase of lubricating oil temperature.The energy of frequency component higher than 10 kHz always increased with the increase of piston-liner clearance.