Abstract: A control system for an engine of a vehicle includes one or more oxygen (O2) sensors disposed proximate to a three-way catalytic converter (TWC) in an exhaust system of the vehicle, the one or more O2 sensors each being configured to measure an O2 level of exhaust gas produced by the engine, and a controller in signal communication with the one or more O2 sensors. The controller is programmed to detect a fuel shut-off (FSO) event where the engine ceases providing fuel to the engine, determine an accumulated gas flow through the TWC during the FSO event, determine the FSO event has ended, and initiate a fuel enrichment event for a predetermined duration where the engine is supplied with a fuel enrichment level having a rich fuel/air ratio. The fuel enrichment level and the predetermined duration are chosen to reduce non-methane hydrocarbon (NMHC) emissions while maintaining NOx emission control.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method for identifying high driveability index fuel for use in a motor vehicle engine includes the steps of determining an engine rotational speed after the engine has started, measuring an elapsed time required for the engine rotational speed to increase from a predetermined low limit to a predetermined high limit, and identifying high driveability index fuel when the elapsed time is greater than a predetermined time limit.