Daimlerchrysler Corporation

Tenneco Automotive Operating Company Inc.

Thomas W Stephens

Wei D Wang

Roger C Sager

Richard K Moote

Chris J Booms

Mark J Poublon

Douglas M Stander

James J Reynolds, Iii

Jason E Wielenga

Danny K Schuelke

David P Ploucha

William E Leisenring

Craig Summers

Craig Keighron

David J Carlson

A method for monitoring an exhaust after-treatment system that doses an exhaust treatment fluid held from a tank into an exhaust stream. The method includes determining a first temperature of the exhaust treatment fluid in the tank using a temperature sensor. If the first temperature of the exhaust treatment fluid is less than a predetermined temperature, a heater is activated to increase the first temperature of the exhaust treatment fluid. The increasing first temperature is then monitored relative to the predetermined temperature. Then, a second temperature when a phase change of the exhaust treatment fluid occurs is detected. The detected second temperature is then compared to the predetermined temperature to determine whether the exhaust treatment fluid is of sufficient quality, or to determine whether the temperature sensor is rational.

Exhaust treatment system with urea temperature rationality diagnostic

A method of diagnosing an operating condition of a short runner valve in an intake manifold of an internal combustion engine using an exhaust sensor in an exhaust manifold of the internal combustion engine. The short runner valve is commanded to an open position for a test period, it is resolved whether the test period has elapsed, and it is determined whether a sensed exhaust gas parameter has exceeded a threshold during the test period. A pass signal is issued if the sensed exhaust gas parameter has exceeded the threshold within the test period. Otherwise, a fail signal is issued if the sensed exhaust gas parameter has not exceeded the threshold within the test period.

Short runner valve diagnostic

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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Dearborn, MI, United States of America

Thomas W Stephens