Measuring and testing – Simulating operating condition – Marine
Patent
1991-02-25
1993-07-20
Raevis, Robert
Measuring and testing
Simulating operating condition
Marine
G01M 1900
Patent
active
052283356
ABSTRACT:
Dual oxygen sensors before and after the exhaust catalytic converter of a motor vehicle combined with a specialized algorithm to substantially continuously compare the real time electric output of the oxygen sensors and, in response to the comparison, output an indication of the activity of the catalyst and failure of the catalyst. The algorithm in substantially real time "monitors" the continuously changing oxygen content of the before and after catalyst exhaust stream and through a phase comparison or an integration process in the preferred embodiment makes the proper comparison for determination of catalyst acceptability or failure. With a microcomputer equipped motor vehicle the algorithm is suitable for on-board continuous monitoring of the exhaust catalyst for indication to the vehicle operator when catalyst failure occurs. Failure can be total catalyst failure or partial failure to a degree where Federal exhaust emissions regulations are no longer met. The algorithm includes filter subroutines to "filter" out momentary excursions of oxygen sensor output due to momentary excursions of overly rich air/fuel ratios. Thus, the algorithm screens out momentary excursions of exhaust air/fuel ratio that even a properly functioning catalyst would be unable to convert and control.
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patent: 5032821 (1991-07-01), Domanico et al.
Meitzler, Allen H., Application of Exhaust-Gas-Oxygen Sensors to the Study of Storage Effects in Automotive Three-Way Catalysts, Sae 800019, 1980.
Clemmens William B.
Koupal John W.
Sabourin Michael A.
Deimen James M.
Raevis Robert
The United States of America as represented by the United States
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