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US 4,782,699 AGranted
Pulsed fuel level indicating system
AssigneeGeneral Motors Corporation
InventorEugene V. Gonze
Life of this patent
Estimating the term…
Abstract
To prevent electrochemical corrosion in a conventional float operated variable resistance fuel level detector due to alcohol in the fuel a current pulse is applied to the detector unit once a minute for a period of 1/1000 second. A solid state circuit stores the level reading between pulses and drives the fuel gauge.
Claims1
In a fuel level indicating system having a sending unit comprising a variable resistor subject to electrochemical corrosion and a display unit for indicating fuel level, an interface circuit for energizing the sending unit and driving the display unit comprising;
- means coupled to the sending unit for generating a series of spaced current pulses having a low "on" duty cycle of the order of 0.1 microsecond and a frequency of occurrence of the order of one current pulse per minute to periodically energize the variable resistor of said sending unit to produce a fuel level output, whereby the electrochemical action on the sending unit is minimized;
- and
- means responsive to the sending unit output and coupled to the display unit for generating a display drive signal.
Dependencies are inferred from the claim text.