Fuel quantity gauge
AssigneeSimmonds Precision Products, Inc.
InventorIrwin Wallman
Life of this patent
Estimating the term…
Abstract
A capacitance type fuel quantity gauge for a fuel tank which includes a probe capacitor in the fuel tank having a capacitance which varies in accordance with the fuel level and connected by one conductor to the output of a Lo-Z oscillator, two oppositely polled diodes connected together and to the capacitor, the positive diodes connected by another conductor to a signal conditioner and the negative diode connected to the one conductor by an inductance, the one conductor connected to the oscillator output and to the signal conditioner by a capacitor and inductance, respectively, so that the one conductor carries both the Lo-Z signal and the DC negative signal.
Claims5
A capacitance type fuel quantity gauge for a fuel tank, comprising in combination:
- a tank unit, including:
- a probe capacitor, the capacitance of which varies in accordance with the fuel quantity gauged;
- a pair of oppositely poled diodes, each having a side connected to one side of the probe capacitor;
- AC blocking means connected to the opposite side of the probe capacitor and to the other side of one of the diodes;
- and DC blocking means connected between the other side of the diodes;
- a signal conditioner, including:
- AC voltage source;
- signal processing means;
- DC blocking means connected to the AC voltage source and the signal processing means;
- and AC blocking means connected to the DC blocking means of the signal conditioner and to the signal processing means;
- and
- a conductor connected to the connection of the DC blocking means of the tank unit to one of the pair of diodes and to the signal processing means;
- and
- a multiplexing conductor connected to the connection of the AC blocking means of the tank unit to the opposite side of the probe capacitor and to the AC blocking means and DC blocking means of the signal conditioner,
- whereby the AC signal voltage from the AC signal source and the DC signal return voltage from of the diodes are carried by the multiplexing conductor.
Dependencies are inferred from the claim text.