Main application

1.In order to obtain high exhaust gas purification rate and reduce the components of (CO) carbon monoxide, (HC) hydrocarbons and (NOx) nitrogen oxides in exhaust gas, EFI vehicles must use three-way catalytic converters. However, in order to effectively use the three-way catalytic converter, it is necessary to accurately control the air-fuel ratio so that it is always close to the theoretical air-fuel ratio. The catalyst is usually installed between the exhaust manifold and the muffler. The oxygen sensor has a characteristic that its output voltage suddenly changes near the theoretical air-fuel ratio (14.7: 1). This characteristic is used to detect the concentration of oxygen in exhaust gas and feed it back to the computer to control the air-fuel ratio. When the actual air-fuel ratio becomes higher, the concentration of oxygen in the exhaust gas increases and the oxygen sensor informs the ECU of the lean state of the mixture (small electromotive force: O volts). When the air-fuel ratio is lower than the theoretical air-fuel ratio, the concentration of oxygen in the exhaust gas decreases, and the state of the oxygen sensor (large electromotive force: 1 volt) is notified to the ECU computer.

2.ECU judges whether the air-fuel ratio is low or high according to the electromotive force difference from the oxygen sensor, and controls the fuel injection duration accordingly. However, if the oxygen transmitter is faulty and the output electromotive force is abnormal, the ECU computer cannot accurately control the air-fuel ratio. Therefore, the oxygen sensor can also make up for the error of air-fuel ratio caused by the wear of machinery and other parts of the EFI system. It can be said that it is the only "intelligent" sensor in the EFI system.

3.The function of the sensor is to determine whether there is excess oxygen in the exhaust gas of the engine after combustion, 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 closed-loop control with excess air factor as the goal; Ensure that the three-way catalytic converter has the maximum conversion efficiency for hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOX) in the exhaust gas, and convert and purify the discharged pollutants to the greatest extent.

Usage introduction

Oxygen sensors are widely used in petroleum, chemical industry, coal, metallurgy, papermaking, fire protection, municipal administration, medicine, automobile, gas emission monitoring and other industries.