The working principle of alumina ceramic sensors

Principles of Aluminum Oxide Ceramic Sensors

Alumina ceramic sensors are situated at the joints of the exhaust pipe, with an alumina ceramic body sealed at one end with a thin platinum coating in front of the catalytic reaction converter. The latter is inserted into a maintenance sleeve and mounted within a metal body. The maintenance sleeve provides additional maintenance functions and secures the sensor to the exhaust intake branch.

Ceramic bodies are exposed externally in the exhaust, while internally they are互通 with the natural environment's air. The principle of the sensor is: when the temperature exceeds 300°C, the used alumina ceramic material acts as an electrical conductor for the compound. Under these前提 conditions, if the percentage composition of oxygen on both sides of the sensor is different, it will cause variations in working voltage on both sides. The variations in measurement values of different oxygen contents in the two natural environments (gas side and exhaust side) inform the ECU that the residual oxygen content in the exhaust can be detrimental to ensuring that harmful organic emissions are converted into an undesirable percentage.

Ceramic materials act as a dispersed system at temperatures below 300°C, thereby preventing sensors from transmitting effective data signals. The ECU plays a particularly crucial role in adjusting the air-fuel mixture after the engine is warmed up (operating in open-loop gain).

The sensor is equipped with heating elements to reach working temperature early. As current passes through the heating elements, it extends the years before the ceramic turns into an electric conductor, and promotes the likelihood of the sensor being installed at a later position in the exhaust pipe.