Volume Measurement of Liquid in a Deformed Tank-Application to the Fuel Meter of Automobiles

This paper describes how to directly and accurately measure liquid volume in a deformed tank which has gas-leaking pinholes, whose attitude changes and walls vibrate, and in which liquid sloshes. The proposed method is different from conventional methods that use level meters, and makes the measurement possible without setting level detecting devices such as a float in the tank. The method makes use of Boyle's law, and the measurement procedure is as follows: (a) first, we determine the volume of gas in the tank by measuring gage pressure increased by compressing the volume of gas in the tank, and (b) next, we find the volume of liquid by subtracting the volume of gas from capacity of the tank. This demonstrates that one standard measurement system can be applied to a variety of tanks with a certain range of volume capacities, whereas conventional methods using level meters require designing and manufacturing different detecting devices depending on the shapes of the tank. Thus, the proposed method can be effectively applied to the accurate measurement of the amount of fuel in automobile tanks which may be deformed and may have different shapes. Here, we focus our discussion only on measuring fuel in an automobile tank, but this method can be generally applied to the measurement of the volume of liquid, solid or powder in a tank. The principle of measurement and the procedure for designing, an instrument system based on the proposed measurement method is described. The validity of the proposed method was experimentally examined and the observed measurement error was about 1% for a standard 50 liter tank.