Catalytic monitoring method

摘要

An adaptive catalytic monitoring method for an engine having two engine banks each coupled to one of two catalytic converters uses first and second exhaust gas oxygen sensors respectively upstream and downstream of one catalytic converter. Third and fourth exhaust gas oxygen sensors are respectively coupled upstream and downstream of the other catalytic converter. Switch ratios are determined for each of the engine banks based the switching ratios of each upstream and downstream pair of exhaust gas oxygen sensors, with the switch ratio being adjusted by an adjustment gain that is a function of airflow and a catalytic converter characteristic. A combination of the adjusted switch ratios is used to determine overall catalytic converter system performance.