Automotive Planar Oxygen Sensors

The oxygen sensor detects the oxygen content in the engine exhaust and sends a corresponding voltage signal to the electronic control unit (ECU) to reflect whether the air fuel mixture ratio is lean or rich.

In the conventional engine management system, there is only one oxygen sensor, which is called the control oxygen sensor and installed in the upstream position of the three-way catalyst.

Newer car is equipped with a diagnostic oxygen sensor installed at the downstream end of the three-way catalytic converter.

The diagnostic oxygen sensor will detect whether the control oxygen sensor is still in the best working condition, and then the ECU can calculate amount of compensation needed for the correction offset.