Oxygen Sensors

Basic Description

An oxygen sensor is an electronic device used to measure the oxygen content in exhaust gasses. In the automotive industry it is also known as a Lambda sensor, and is used to regulate the air/fuel mixture and exhaust gas emissions in the internal combustion engine. The lambda sensor is used to indicate whether the fuel mixture is rich or lean. The levels of oxygen are determined by exposing one electrode to the outside air and another to the exhaust gas. The difference in oxygen content causes a flow of electrons through a ceramic element that generates a voltage potential between two boundary layers. The voltage created is directly related to the level of oxygen content in the exhaust gas.

The lambda sensor is very sensitive to temperature. The temperature of the ceramic element will determine its ability to conduct the oxygen ions and essentially influence the response time of the sensor. Most sensors are manufactured with an integrated electrical heating element to sustain the response time at low exhaust temperatures. This function assures that the emissions of the vehicle are controlled over a wider range of engine operating temperatures, especially during cold starts.

Manufacturers

Beru, Bosch, Delphi, Denso

For More Information

[1] How does the Oxygen Sensor in a Car Work?, HowStuffWorks.com, Apr. 1, 2000.

[2] Oxygen Sensor, Wikipedia.

[2] Oxygen Sensors Are a Critical Key to Passing Emissions, Autohaus website.

[4] The Modern Oxygen Sensor, Bosch Product Information. [pdf]