Design and evaluation of a single-tube cross-capacitance fuel level sensor

Abstract

In order to improve the accuracy and reduce the weight of the cross-capacitor fuel level sensor, a novel single-tube cross-capacitor fuel level sensor is designed. Specifically, the fuel level measurement model of the single-tube cross-capacitance sensor is established, and the relationship between the measured liquid level and the sensor output capacitance is derived. Then, a finite element analysis model is constructed to solve the capacitance output of the sensor. The results of experiments conducted demonstrate that the output capacitance value of the designed single-tube cross-capacitive sensor changes linearly in the range 0-14 pF, with linearity ? 0.8%, hysteresis error ? 0.1%, and maximum reference error ?1.0% FS at a liquid level of 120 mm. The optimized structural parameters were as follows: plate gap angle ? = 2?, quartz tube inner radius R0 = 11.5 mm, quartz tube thickness R1 ? R0 = 1.6 mm, and sensitivity = 0.0723 pF/mm (representing an 11.1% increase after optimization). The cross-capacitive fuel level sensor developed in this study is both lightweight and high precision.