Oxygen Sensor: Description and Operation

The sensor is installed in the exhaust pipe and makes use of solid electrolyte oxygen concentration cell which is characterized by sharp changes in the output voltage in the vicinity of the air/fuel ratio. Using theses changes, then oxygen sensor senses the oxygen concentration in the exhaust gas and feeds it back to the ECU. The ECU then judges if the air/fuel ratio is richer or leaner compared to the ideal ratio and provides feedback control to adjust the ratio accordingly.