Electronic circuit for fuel level sensor

Abstract

Corrosion of the fuel tank float device by electrolysis is minimized by driving the fuel level sender with short duty cycle pulses instead of a continuous current. While the fuel level sender is energized by a pulse, the analog sample and hold circuit obtains a reading from which fuel level can be determined. A synchronizing circuit controls the sequence in which the fuel level sender is energized and the reading taken, to insure that readings are taken during steady state conditions. An impedance matching circuit compensates for nonlinearities of the fuel level gauge. The impedance matching circuit includes a pair of precision resistors and a voltage multiplier circuit. The impedance matching circuit allows the moving coil fuel level gauge to be energized in a fashion which simulates a continuous current flowing between fuel level sender and gauge. The circuit can be interposed between conventional fuel level sender and conventional moving coil gauge, requiring little or no modification of those components but greatly reducing corrosion due to electrolysis.

Dependencies are inferred from the claim text.