APPROACH FOR DETERMINING EXHAUST GAS SENSOR DEGRADATION

摘要

A method for determining degradation of an exhaust gas sensor positioned in an exhaust system for an internal combustion engine of a vehicle is provided. The method includes modulating an air/fuel ratio of gas exhausted by the internal combustion engine to the exhaust system through a cycle that includes at least one rich-to-lean transition and at least one lean-to-rich transition, indicating a degradation condition of the exhaust gas sensor in response to at least one of a rich-to-lean response duration of the exhaust gas sensor and a lean-to-rich response duration of the exhaust gas sensor being greater than a delay threshold, and indicating the degradation condition of the exhaust gas sensor in response to a ratio of the rich-to-lean response duration to the lean-to-rich response duration being greater than an asymmetry threshold that is relative to an axis of symmetry of the rich-to-lean response duration versus the lean-to-rich response duration.