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Oxygen Sensor Standard Configuration For Automobiles

Oxygen sensor is the standard configuration of the car, using the Nernst principle. It is the use of ceramic sensors to measure the oxygen potential in automotive exhaust pipe, the chemical equilibrium principle to calculate the corresponding oxygen concentration, to monitor and control the combustion air-fuel ratio, to ensure product quality and exhaust emission standards of the measurement elements. It has the advantages of simple structure, quick response, easy maintenance, convenient use and accurate measurement.

Oxygen sensors are essential components in an engine that uses a ternary catalytic converter to reduce exhaust pollution. As the air-fuel ratio of mixed gas deviates from the theoretical air-fuel ratio, the purification capability of the ternary catalysts to CO, HC and NOx will be reduced drastically, so the oxygen sensor is installed in the exhaust pipe to detect the concentration of oxygen in the exhaust gas, and to send the feedback signal to the ECU, and then the ECU controls the increase or decrease of fuel injection quantity, The air-fuel ratio of the mixed gas is controlled near the theoretical value.

In order to obtain high exhaust gas purification rate and reduce the carbon monoxide, (HC) hydrocarbons and NOx compounds in exhaust gas, the ternary catalyst must be used. However, in order to effectively use the ternary catalytic converter, the air-fuel ratio must be controlled precisely so that it is always close to the theoretical air-fuel ratio. The catalyst is usually installed between the exhaust manifold and the muffler. An oxygen sensor has a property that has a mutation in the voltage output near the theoretical air-fuel ratio (14.7:1). This feature is used to detect the concentration of oxygen in the exhaust and feed back to the computer to control the air-fuel ratio. When the actual Air-fuel ratio is higher, the oxygen concentration increases in the exhaust gas and the oxygen sensor informs the ECU of the state of the mixture (small electromotive force: o Volt). When the air-fuel ratio theory is low, the concentration of oxygen in the exhaust gas decreases while the state of the oxygen sensor (Big electromotive force: 1 volts) Notices (ECU) computer.

The ECU judges the low or high air-fuel ratio according to the electromotive force difference from the oxygen sensor, and controls the fuel injection duration accordingly. However, such as the oxygen transmitter failure to make the output electromotive force is not normal, (ECU) computer can not accurately control the air-fuel ratio. So the oxygen sensor can also make up for the error caused by the abrasion of other parts of mechanical and EFI system. It can be said that the only "smart" sensor in the EFI system.

The role of the sensor is to determine the excess of oxygen in the exhaust of the engine after combustion, namely oxygen content, and converts the oxygen content to the voltage signal to the engine computer, enables the engine to realize the closed-loop control with the excessive air factor as the target; to ensure the hydrocarbon (HC) in the exhaust of the ternary catalytic converter, Carbon monoxide (CO) and nitrogen oxides (NOx) three kinds of pollutants have the greatest conversion efficiency, the largest degree of emission of pollutants conversion and purification.