The role of the front and rear oxygen sensors, the working principle of the oxygen sensor

The oxygen sensor we are talking about today is the key feedback sensor in the EFI engine control system.Secondly, it is divided into front oxygen sensor and rear oxygen sensor.YuanCatalysis is the boundary. Before the three-way catalysis is the front oxygen sensor, and the one after the three-way catalysis is the rear oxygen sensor. So, what are the roles of the front and rear oxygen sensors? Let's answer it for you.

First, let’s talk about the front oxygen sensor. Its function is to detect the oxygen concentration in the exhaust gas of the engine, and then transmit the acquired information to the ECU in the form of electrical signals, and the ECU will determine the air-fuel ratio based on the oxygen concentration information obtained. Feedback control. As for the rear oxygen sensor, it is mainly used to detect the oxygen concentration of exhaust gas after three-way catalytic purification. If the oxygen concentration data obtained by the front oxygen sensor and the rear oxygen sensor are the same, then the three-way catalyst has failed.

Working principle of oxygen sensor

The working principle of the oxygen sensor is actually the same as the battery we usually see. The zirconium oxide element inside is similar to the role of electrolyte. Under certain conditions (high temperature and platinum catalysis), the difference in oxygen concentration between the inner and outer sides of the element is used to form a battery with a difference in oxygen concentration (generating a potential difference). Then, if the concentration difference between the inside and outside of the zirconium tube is greater, the potential difference will increase accordingly. On the contrary, if the concentration difference is small, the resulting potential difference is naturally relatively small.