EXCESS AIR COEFFICIENT CONTROL METHOD AND DEVICE FOR CATALYTIC CONVERTER, VEHICLE, AND STORAGE MEDIUM

An excess air coefficient control method for a gasoline engine catalytic converter, comprising: in an engine idle stage before the ignition of a catalytic converter and after the start of an engine, controlling an excess air coefficient to alternately switch between a first set value and a second set value until an excess air coefficient sensor achieves a closed loop; when the excess air coefficient is controlled at the first set value, making the air-fuel ratio greater than 14.7 so as to perform lean control; and when the excess air coefficient is controlled at the second set value, making the air-fuel ratio less than 14.7 so as to perform enrichment control. Said method is able to reduce the emission amounts of NMOG and NOX at low cost. Also disclosed are an excess air coefficient control device for a gasoline engine catalytic converter, a vehicle and a computer readable medium.