Method and system for generating an inferred EGO signal in an asymmetrical Y-pipe exhaust system

摘要

A method and system for generating an inferred EGO sensor signal for use in monitoring operation of a catalytic convertor in an asymmetrical Y-pipe vehicle exhaust system utilizes current engine airflow and engine speed readings as address inputs for a look-up table of predetermined time delay values. The addressed time delay values are used to retrieve previously stored upstream EGO sensor signals corresponding to the time delay values. An inferred EGO sensor signal is then generated based on the retrieved EGO sensor signals, thus providing an inferred EGO sensor signal which accounts for the exhaust transport delay down the different respective exhaust pipe legs.