基于振动速度的柴油机缸内峰值压力提取方法研究

基于数值模拟和试验研究,结合柴油机缸盖振动速度与缸内压力信号对应关系,根据微积分理论推导出描述柴油机缸内峰值压力的振动速度特征参数提取方法。模拟结果表明:基于振动速度提取的峰值位移和缸内峰值压力为近似线性对应关系,峰值位移可准确描述缸内峰值压力变化。试验结果表明:振动速度提取的峰值位移和缸内峰值压力有一致的变化趋势,两者为近似线性对应关系,但受干扰信息和工况波动等因素影响,线性度略差。结合不同工况提取的峰值位移和缸内峰值压力数据,基于最小二乘法理论拟合出不同机型峰值位移和缸内峰值压力线性关系曲线,基于该线性关系可实现基于振动速度的缸内峰值压力定量评价。

Extraction Method of In-Cylinder Peak Pressure Based on Vibration Velocity of Diesel Engine

According to the relationship between vibration velocity and in-cylinder pressure for cylinder head of diesel engine,the extraction method of vibration velocity characteristic parameter for describing the in-cylinder peak pressure of diesel engine was deduced with calculus theory based on numerical and experimental research.The results show that the peak displacement extracted from vibration velocity is approximately linear to the peak pressure and the peak displacement can hence describe the change of in-cylinder peak pressure accurately.The experimental results indicate that the peak displacement calculated by vibration velocity has the same trend with in-cylinder pressure,which shows the approximate linear relationship.However,the linearity is slightly worse due to the influence such as interference information and fluctuations in operating conditions.The fitting linear relationship between peak displacement and peak pressure for different engines is conducted by using the data extracted under different conditions based on least square method,which can realize the quantitative evaluation of in-cylinder peak pressure based on the vibration velocity.