柴油机燃烧过程和缸盖振动信号关系模拟分析

Correlations Between Vibration and Combustion Excitation of Diesel Engines

利用多维实体模型对195柴油机振动系统的相频特性、幅频特性进行了分析,结合缸内压力信号频谱特点,分析了缸盖振动信号与缸内压力、振动信号特征参数和燃烧状态特征参数之间的关系。指出缸内压力单独作用时,峰值压力前,缸盖表面振动位移和缸内压力、振动速度和压力升高率、振动加速度和压力二次导数有相似的变化趋势。缸盖表面振动位移能反映出最大峰值压力出现时刻、最大峰值压力和平均指示压力的变化;振动速度能反映出最大峰值压力出现时刻、最大压力升高率出现时刻、最大压力升高率和燃烧始点位置的变化;振动加速度信号能反映出燃烧始点位置和最大压力升高率出现时刻的变化。

A finite element model of a 195 diesel engine was developed to analyze the correlations between cylinder head vibration and in-cylinder pressure.Combined the amplitude responses and phase responses obtained using the model with the spectrum of in-cylinder pressure,the correlations between vibration and incylinder pressure and between vibration parameters and combustion parameters were analyzed.Results show that prior to peak pressure,vibration and in-cylinder pressure have the same trace.The vibration displacement excited by combustion can be used to indicate the location of peak pressure,the peak pressure and the indicated mean effective pressure.Vibration speed can describe the location of maximum rate of pressure rise,the combustion timing,locations of peak pressure and maximum rate of pressure.Vibration acceleration can describe location of maximum rate of pressure rise and combustion timing.