Automobile Fuel Gaging by Pneumatic Methods

Abstract

The volume of gas in a closed liquid tank can be calculated from measurement of changing pressure of gas in the tank that occurs according as the change in the volume of gas in the tank by applying the ideal gas law. The volume of liquid in the tank is obtained by subtracting the volume of gas from the capacity of tank.
This paper treats the substantial problems which could occur when the above idea is applied to a real flexible automobile fuel tank, i.e., (1) how to compensate deformation of the flexible tank, which occurs according as the change in the volume of gas in the tank, (2) how to design a measurement system effectively implemented for automobile fuel tanks, and (3) what is the desired measuring condition to reduce effects of pressure noise occurring in the fuel tank of a running automobile, and presents a new measurement system that could solve the problems (1) and (2), and shows the desired condition in (3).
A measurement system realized by analog electronics circuits and measurements by the circuit demonstrate the proposed method can be effectively applied to automobile fuel gages.