缸内压力信号中燃烧激励引起高频谐波的特征参数

Characteristic parameters of high frequency harmonics caused by combustion excitation in cylinder pressure signal

针对振动信号与缸内压力信号辨识的相位燃烧特征参数间存在滞后角、且不同工况下滞后角不一致的问题,研究了缸内压力信号中可用于表征高频谐波能量的特征参数.分析了缸内压力信号的时频分布特点,确定燃烧激励信号的频带范围;建立了单缸柴油机一维仿真模型,对峰值压力等参数进行了分析.结果表明:峰值压力、最大压升率、最大压升率与燃烧始点到最大压升率点间隔角比值及燃烧始点到峰值压力点间隔角与缸内压力信号高频谐波能量呈近似线性关系;所提出的参数,包括实测振动速度信号中的pirA′B′,pirA′B′δφ′,δθ′能用于表征高频谐波能量,为基于振动速度信号特征参数修正相位滞后角提供了参考.

To solve the problems of existing lag angle between the phase combustion parameters identified by vibration signal and cylinder pressure signal and of existing different lag angles under different working conditions,the parameters for characterizing the high-frequency harmonics of in-cylinder pressure signal were investigated.The S-transformation of cylinder pressure was analyzed to determine the range of frequency distribution caused by the combustion excitation.The one-dimensional simulation model of the single-cylinder diesel engine was established to analyze the maximum pressure.The results show that the maximum pressure rise rate,the peak pressure,the ratio of the maximum pressure rise rate to the interval between the start of combustion and the maximum pressure rise rate and the interval between the start of combustion and the peak pressure are approximately linear to the high frequency energy of the cylinder pressure signal.In the vibration velocity signal,the corresponding parameters of pir A′B′,pir A′B′δφ′andδθ′can be used to represent the high-frequency energy.A reference is provided for correcting lag angle based on characteristic parameters of vibration velocity signals.