Principle:
The oxygen sensor is a standard configuration on the car. It uses ceramic sensitive elements to measure the oxygen potential in the car exhaust pipe, and calculates the corresponding oxygen concentration by the chemical balance principle to monitor and control the combustion air-fuel ratio to ensure product quality And the measuring element that meets the exhaust emission standard.
Oxygen sensor is widely used in the atmosphere control of various types of coal combustion, oil combustion, gas combustion, etc. It is the best combustion atmosphere measurement method at present. It has the advantages of simple structure, rapid response, easy maintenance, convenient use, accurate measurement, etc. Using the sensor to measure and control the combustion atmosphere can not only stabilize and improve product quality, but also shorten the production cycle and save energy.
Make up
The oxygen sensor uses the Nernst principle.
The core element is a porous ZrO2 ceramic tube, which is a solid electrolyte, with porous platinum (Pt) electrodes sintered on both sides. At a certain temperature, due to the different oxygen concentrations on both sides, the oxygen molecules on the high-concentration side (the inner side of the ceramic tube 4) are adsorbed on the platinum electrode and combine with the electrons (4e) to form oxygen ions O2-, which makes the electrode positively charged, O2 -The ions migrate to the low oxygen concentration side (exhaust gas side) through the oxygen ion vacancies in the electrolyte, so that the electrode is negatively charged, that is, a potential difference is generated.
When the air-fuel ratio is low (rich mixture), there is less oxygen in the exhaust gas, so there are less oxygen ions outside the ceramic tube, forming an electromotive force of about 1.0V;
When the air-fuel ratio is equal to 14.7, the electromotive force generated on the inner and outer sides of the ceramic tube is 0.4V~0.5V, and this electromotive force is the reference electromotive force;
When the air-fuel ratio is high (lean mixture), the oxygen content in the exhaust gas is high, and the oxygen ion concentration difference between the inside and outside of the ceramic tube is small, so the generated electromotive force is very low, close to zero.
Function
The function of the sensor is to determine the information about whether there is excess oxygen in the exhaust after combustion of the engine, that is, the oxygen content, and convert the oxygen content into a voltage signal and transmit it to the engine computer, so that the engine can realize the closed-loop control with the excess air factor as the target; to ensure; The three-way catalytic converter has the greatest conversion efficiency for the three pollutants of hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOX) in the exhaust gas, and maximizes the conversion and purification of emission pollutants .
Purpose
Oxygen sensors are widely used in industries such as petroleum, chemical, coal, metallurgy, papermaking, fire protection, municipal administration, medicine, automobiles, and gas emission monitoring.
YASEN is an manufacture enterprise professional in the production of VM oxygen sensors, if you need order them, welcome to contact us!
Post time: Nov-24-2021