Oxygen Sensor: Description and Operation

Oxygen Sensor With Internal Heater:

An oxygen (Lambda) sensor is used to provide more precise control of air/fuel mixtures. This system operates by measuring oxygen content in exhaust gases, as the amount of oxygen remaining in the exhaust gases is directly proportional to the air/fuel ratio of mixtures entering the engine. Oxygen sensors function only after exceeding approx. 600° F. In order to more quickly allow reliable oxygen sensor output a 12V heating element is built into the sensor. The sensor, mounted in the exhaust stream, reacts to the oxygen remaining in the exhaust gases and produces a variable voltage signal (0.1 - 1.0 VDC) depending upon the oxygen content.

Oxygen Sensor Voltage:

A rich mixture will produce a high voltage (up to 1.0V) and a lean mixture will produce a lower voltage.