The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 30, 1994
Filed:
Apr. 15, 1992
Nick M Johnson, Los Altos, CA (US);
Chun-Foong Cheah, San Francisco, CA (US);
Other;
Abstract
A circuit for responding to the output of a capacitive fuel sensor that can distinguish gasoline from methanol and produces an output that is related to the methanol proportion. The response is independent of the conductivity in the sensor resulting from fuel contamination. A square wave is employed to excite the sensor and the circuit provides for stabilizing the square wave amplitude. The circuit includes an amplitude modulation detector that converts the square wave transients into a fuel composition related voltage output that can be applied to an engine control mechanism that will adjust the automotive engine to operate efficiently with the fuel being supplied. Circuits are shown for linearizing the fuel composition to voltage response and a charge dispenser amplitude modulation detector is described wherein the detection occurs only during the square wave transient interval.