What is the working principle of an oxygen sensor?

[AddysonLee]

An oxygen sensor utilizes a ceramic sensing element to measure the oxygen potential in a vehicle's exhaust pipe. Based on the principle of chemical equilibrium, it calculates the corresponding oxygen concentration to monitor and control the air-fuel ratio of combustion, ensuring product quality and compliance with exhaust emission standards. Relevant information about oxygen sensors is as follows: 1. The oxygen sensor operates on the Nernst principle. Its core component is a porous ZrO2 ceramic tube, which is a solid electrolyte with porous platinum (Pt) electrodes sintered on both sides. 2. At a certain temperature, due to the difference in oxygen concentration on both sides, oxygen molecules on the high-concentration side (inside the ceramic tube) are adsorbed on the platinum electrode and combine with electrons (4e) to form oxygen ions O2-, making this electrode positively charged. The O2- ions migrate through oxygen ion vacancies in the electrolyte to the low-oxygen-concentration side (exhaust gas side), making that electrode negatively charged, thus generating a potential difference.