全可变液压气门系统气门运动规律动态测量与数据处理方法

Method of dynamic measurement and data processing of valve motion law for fully variable hydraulic valve system

搭建气门升程测试平台,测量全可变液压气门系统(fully hydraulic variable valve system,FHVVS)的气门运动规律,分析发动机转速、传感器动态响应特性以及数据处理方法对气门升程测量精度的影响。结果表明:凸轮轴瞬时转速波动随驱动电机转速的降低而增大,通过角标信号对采集的气门升程进行数据处理,可以减少由于瞬时转速波动导致的气门升程测量误差;传感器动态响应特性不足造成气门升程相位迟滞;气门加速度波动频率与液压压力波动频率应一致,通过选取合适的滤波截止频率准确计算气门加速度;经五点三次平滑法处理后的气门升程更接近实际结果。

A valve lift test platform is established to measure the valve lift of a fully hydraulic variable valve system(FHVVS),the effects of engine speed,sensor dynamic response characteristics,and data processing methods on the accuracy of valve lift measurement,are analyzed.The results indicate that the instantaneous speed fluctuation of the camshaft increased with the decrease of driving motor speed.By processing the collected valve lift data with an angle signal,the measurement error caused by instantaneous speed fluctuation can be effectively reduced.Moreover,insufficient sensor dynamic response characteristics may result in a phase lag in valve lift measurement.The consistency between the frequency of hydraulic pressure fluctuation and valve acceleration fluctuation can be used as a criterion for judging interference signal and valve acceleration signal.Based on this criterion,an appropriate filter cutoff frequency can be selected to accurately calculate valve acceleration.The valve lift data processed by the five-point,three-time smoothing method is more in line with the actual value.