2. Measure whether there is excess oxygen in the exhaust gas after engine combustion, that is, oxygen content, and convert the oxygen content into voltage signal and transmit it to the engine computer, so that the engine can realize closed-loop control of excess air coefficient; 2. Ensure that the three-way catalytic converter has the maximum conversion efficiency for hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOX) in exhaust gas, and the maximum conversion and purification effect for discharged pollutants.

3. The oxygen sensor can also make up for the air-fuel ratio error caused by the wear of the mechanical parts of the EFI system; 3. Oxygen sensor is an important part of the engine, which uses three-way catalytic converter to reduce exhaust pollution.