Patent ID: 10519839

Abstract:
An exhaust purification system of an internal combustion engine comprises a catalyst 20, an air-fuel ratio sensor 41, a current detection device 61, a voltage application device 60, a voltage control part 71 and an air-fuel ratio control part 72. The air-fuel ratio control part controls the air-fuel ratio so that the output current of the air-fuel ratio sensor becomes a predetermined target value. The voltage control part performs at least one of voltage lowering control setting the applied voltage to a first voltage lower when the air-fuel ratio becomes higher than a lean judged air-fuel ratio, and a voltage raising control setting the applied voltage to a second voltage when the air-fuel ratio becomes lower than a rich judged air-fuel ratio. The reference voltage is a voltage at which the output current of the air-fuel ratio sensor becomes zero when the air-fuel ratio is the stoichiometric air-fuel ratio.