Method for detection of fluctuation in air/fuel ratio of air-fuel mixture fed to internal combustion engine

摘要

A sensor comprises a layer of an oxygen ion conductive solid electrolyte such as stabilized zirconia, two electrode layers of a catalytic metal such as platinum formed porously on both sides of the electrolyte, only one of them formed on first side of the electrolyte layer being directly exposable to an exhaust gas stream, and a gas passage arranged to allow the exhaust gas to contact the other side of the electrolyte layer with a time lag behind the contact of the gas stream with the first side. A fluctuation in the air/fuel ratio of an air-fuel mixture fed to the engine across the stoichiometric ratio can be detected by this sensor since the fluctuation and the aforementioned time lag cause a difference between oxygen partial pressure on one side of the electrolyte layer and that on the other side, resulting in development of an output voltage of the sensor.