Daimlerchrysler Corporation

Craig Summers

Wei D Wang

Richard K Moote

Mark J Poublon

Chris J Booms

Douglas M Stander

Jason E Wielenga

Danny K Schuelke

Thomas W Stephens

William E Leisenring

Dave Carlson

Tom Stephens

David J Carlson

Bill Leisenring

In a motor vehicle having an engine with an exhaust catalyst and an oxygen sensor upstream of the catalyst and an oxygen sensor downstream of the catalyst, a method for detecting whether the catalyst has aged. Over a test block period of time, the method periodically obtains upstream data points from an oxygen sensor located upstream of the catalyst and from and oxygen sensor located downstream of the catalyst. Absolute differences are calculated between consecutive pairs of the upstream data points and the downstream data points. A ratio between the sums of absolute differences is then calculated, and the ratio is used to determine whether the catalyst has aged.

Exhaust catalyst monitoring arrangement

A non-intrusive method and arrangement for detecting the aging of an oxygen sensor, without increasing tailpipe emissions, is provided. The method detects an aging oxygen sensor, located between a motor vehicle engine and a catalytic converter, by sampling a series of oxygen level signals taken over a calibratable time block only when at least one engine operating condition satisfies a predetermined criterion whereunder the method will not intrude upon the engine controller's ability to minimize undesirable exhaust emissions. After a series of signal processing, the samplings are then compared to calibratable thresholds in order to determine the aging degree of the oxygen sensor.

Oxygen sensor monitoring arrangement

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Northville, MI, United States of America

Craig Summers