单管计算电容式燃料液位传感器理论特性研究

Research on the Theoretical Characteristic of Single-Tube Cross Capacitance Fuel Level Sensor

由于计算电容原理在电磁计量领域具有极高的准确度,将其应用在传感器的研制上具有重要的现实意义。针对传统双层套筒的电容式液位传感器在加工及装配过程中极易引入误差、存在毛细现象等问题,首次将计算电容原理运用在燃料液位测量领域,对计算电容原理进行深入研究,设计新的计算电容结构并对其进行修正,同时结合新的结构建立新的燃料液位测量模型,得出相应的修正系数及液位测量公式。最后,以纯度为99.8%的无水乙醇作为被测燃料进行液位测量试验,燃料液位变化范围为180 mm,输出电容值在0.6 p F^17 p F之间,实验结果表明:燃料液位与传感器输出电容值具有良好线性关系,线性度达到0.48%。该研究为计算电容原理在工程中的应用奠定了理论基础。

It is of important practical significance to use the principle cross capacitance on sensor development be-cause of its extremely high accuracy in the field of electromagnetic metrology. The principle firstly used in fuel levelmeasurement to overcome the capillarity and the error due to machining and assembly in traditional capacitance lev-el sensor. With in-depth research on the principle,a new structure of cross capacitance was designed and modified.Meanwhile the appropriate correction parameter and measuring formulas was obtained by the fuel level measure-ment model of the new structure. Finally,the fuel level is experimented with purity 99.8% alcohol,the range of mea-surement is 180 mm,and the output capacitance is between 0.6 p F-17 p F. The results indicate that the fuel levelhas a good linear with the output capacitance,the linearity is respectively 0.48%. The research laid a foundation forthe application of the principle cross capacitance in engineering.