自由活塞斯特林发动机活塞位移测量

Study on Displacement Measurement of Free Piston Stirling Engine

自由活塞斯特林发动机活塞往复振动位移对研究发动机特性具有重要意义,然而该类发动机活塞位于高压封闭腔体内且结构较为紧凑,其活塞往复振动位移难于直接进行测量。加速度传感器具有尺寸小、安装方便和工作稳定等特点,提出了采用加速度传感器测量活塞位移的方法。根据加速度传感器测量位移的原理,建立了一套加速度传感器测量自由活塞斯特林发动机活塞位移的标定试验系统,以位移传感器为基准测试并分析了不同活塞振幅和不同振动频率下加速度传感器测量位移的误差大小。实验结果表明,在活塞振幅小于8 mm,振动频率大于20 Hz条件下,加速度传感器测量位移的误差小于5%。因此加速度传感器可以用于测量自由活塞斯特林发动机的活塞往复运动位移。最后成功把加速度传感器测量的自由活塞斯特林发动机活塞振动位移用于发动机循环指示功的实验研究。

The displacements of piston and displacer are meaningful to study on the characteristics of free piston Stirling engine.However,the pistons are in a high pressure and compact space,so the displacements are difficult to measure directly.Base on the small size,easy installation and stable operation,in this paper the acceleration sensor has been used to measure the displacements.According to the principle of measuring the displacement with acceleration sensor,the calibration experiment system has been built.The displacement sensor is used to calibrate the acceleration sensor at different frequencies and amplitudes.Experimental results show that the deviation is less than 5%when the frequency is higher than 20 Hz and amplitude is smaller than 8 mm.So the acceleration sensor could be used to measure the displacements of free piston Stirling engine.Finally,the acceleration sensor is successfully used in the experimental study of engine cycle PV work.