How the lambda sensor works

An optimum fuel-air mixture (ratio 1:14) is required so that the catalytic converter can develop its effect fully. The intelligent technology of the lambda sensor determines the residual oxygen content in the exhaust gas and thus delivers a value with which the fuel-air mixture can be regulated.

The measuring basis is an electric voltage that arises in the sensor - due to the difference between the amount of oxygen in the outside air and the oxygen content of the exhaust gas.

This voltage is measured by two wafer-thin electrodes making contact with the outside air and with the exhaust gas. The basic material of the lambda sensor is a ceramic material permeable to oxygen ions - as a rule zirconium oxide.