How air-fuel ratio works
In order to optimize the exhaust gas catalytic rate (more than 90%), it is necessary to install an oxygen sensor in the exhaust pipe of the engine and realize closed-loop control. The working principle is that the oxygen sensor will measure the concentration of oxygen in the exhaust gas and convert it into an electrical signal and then send it. For the ECU, the air-fuel ratio of the engine is controlled in a narrow, near-ideal area (14.7:1). If the air-fuel ratio is large, although the conversion rates of CO and HC are slightly increased, the conversion rate of NOx is sharp. The drop is 20%, so the best air-fuel ratio must be guaranteed, and the best air-fuel ratio is achieved. The key is to ensure that the oxygen sensor works properly. If the fuel contains lead and silicon, the oxygen sensor will be poisoned. In addition, improper use can also cause malfunctions such as carbon deposition of the oxygen sensor, ceramic chipping, heater resistance wire burnout, and internal line breakage. The failure of the oxygen sensor causes the air-fuel ratio to be out of alignment, the exhaust condition to deteriorate, the catalytic converter efficiency to decrease, and the service life of the catalytic converter to be reduced for a long time.