Exhaust system monitoring methods and systems

Abstract

A diagnostic system for an exhaust system including a catalyst and a post-catalyst oxygen sensor is provided. The system generally includes a fuel control module that commands fuel to transition from a rich condition to a lean condition and that commands fuel to transition from the lean condition to the rich condition. A first diagnostic module monitors the post-catalyst oxygen sensor during the transition from the rich condition to the lean condition. A second diagnostic module monitors the catalyst during the transition from the lean condition to the rich condition.

Description

technical field [0001] The present invention relates to methods and systems for diagnosing malfunctions of catalysts and post-catalyst oxygen sensors in vehicles. Background technique [0002] During combustion, gasoline is oxidized and hydrogen (H) and carbon (C) combine with air. Formation of different compounds including carbon dioxide (CO 2 ), water (H 2 O), carbon monoxide (CO), nitrogen oxides (NO X ), unburned hydrocarbons (HC), sulfur oxides (SO X ) and other compounds. [0003] Motor vehicle emissions systems include catalytic converters that convert exhaust gases chemically into carbon dioxide (CO 2 ), nitrogen (N) and water (H 2 O) to reduce exhaust emissions. The exhaust gas oxygen sensor produces a signal indicating the oxygen content of the exhaust gas. An inlet or front catalyst oxygen sensor monitors the oxygen content associated with the inlet exhaust stream of the catalytic converter. The import O 2 The sensor is also the primary feedback mechanis...

AI Technical Summary

Problems solved by technology

However, multiple intrusive detections increase exhaust emissions and / or cause engine instability and reduced drivability noticeable by the vehicle driver

Furthermore, traditional diagnostic procedures are complex and computationally intensive than desired

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