Abstract: Apparatus for determining the fuel level in a fuel tank and for detecting the presence of water in the fuel tank. The fuel level in the tank is determined by detecting the change in capacitance between a pair of electrodes positioned with a generally vertical orientation so that as the fuel rises in the tank, an increasing area of the plates is adjacent to the fuel. Since the presence of water in fuel is very undesirable, the apparatus also includes means for detecting this water before it can effect engine performance and before it can effect the accuracy of the fuel level indicating circuitry.

Abstract: Apparatus for determining the liquid level in tanks, such as are used in recreational vehicles, which utilizes a pair of parallel plates secured to the outside of the tank to avoid contact with the liquid inside of the tank. The plates have a generally vertical orientation so that as the liquid rises in the tank, an increasing area of the plates is adjacent to the liquid. The change in capacitance between the plates as a function of liquid level is utilized to generate an electrical signal indicative of liquid level. The problems caused by highly viscous liquids coating the inside surface of the tank and yielding false readings are solved by utilizing a high frequency driving signal.

Abstract: Apparatus for determining the liquid level in tanks, such as are used in recreational vehicles, which utilizes a pair of parallel plates secured to the outside of the tank to avoid contact with the liquid inside of the tank. The change in capacitance between the plates as a function of liquid level is utilized to generate an electrical signal indicative of liquid level. With the present invention, more than one tank can be connected to the same measuring electronics and the measuring electronics may be mounted at a central point, adjacent the liquid level visual indicator. The present apparatus is relatively independent of variations in conductivity of the liquid in the tank and relatively independent of operating frequency. The apparatus is relatively unaffected by the capacitance of long cables between the plates and the measuring electronics.