顶置凸轮机构气门理论运动规律的精确计算

介绍了一种根据凸轮升程数据求取气门理论运动规律的计算方法。由于顶置凸轮轴式配气机构的摇臂比是变化的,为提高计算精度,采取了3项措施:根据凸轮升程数据求取气门理论升程数据并对该数据进行曲线拟合;将从动件的升程曲线分为缓冲段和工作段分别进行曲线拟合;将最优化计算和最小二乘法相结合对工作段进行曲线拟合。结果表明,这种计算方法精度高,函数表达式简单、直观,便于分析气门运动规律和凸轮主要设计参数。

Accurate Calculation of Valve Theoretic Movement Rules on OHC

A new mathematical method of valve theoretic movement rules according to the cam lift data was introduced.Owing to the fact that the rocker arm ratio of OHC valve train was variable,three measures were adopted for raising the calculation precision.The first was fitting the valve theoretic lift data which was calculated according to the cam lift data.The second was dividing the whole lift curve into two sections,the transition and working section which were fitted singly.The third was fitting the working section by using the methods of optimization and the least squares.The calculation results indicate that the counted precision of this new mathematical method is higher;the expression of fitting function is simple and visual;it is convenient to analyze the valve movement rule and the design parameters of cam profile.