Method and system for monitoring evaporative purge flow

U.S. Patent Number: 5386812

Abstract: An evaporative purge flow monitoring system is provided for use in a motor vehicle having a fuel tank and an internal combustion engine having an intake manifold. The purge flow monitoring system includes an evaporation canister in fluid communication with the fuel tank and a canister purge valve in fluid communication with the fuel tank and evaporation canister. A thermistor/resistor network is further provided in fluid communication with the canister purge valve and the intake manifold. An electronic engine control (EEC) assembly is similarly provided in electrical communication with the canister purge valve and the thermistor/resistor network such that the EEC is adapted to determine the voltage difference across the thermistor/resistor network resulting from discrete measurements within the canister purge valve duty cycle during a selected window of operation and compare the determined voltage difference to a calibrated difference so as to detect malfunctions of the canister purge valve.

Inventors: Curran; Patrick J. (Farmington Hills, MI), Niessen; Paul M. (Canton, MI), Schwager; Bryce A. (Ypsilanti, MI)

Assignee: Ford Motor Company (Dearborn, MI)

Application Number: 08/138,111

Issued: 1995-02-07

Expired: 2007-02-07

Classes: 123/520

Field of search: 123/516,518,519,520,198D

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