Patent ID: 11898511
Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 3:
4. The control device according to claim 2, wherein the one or more electronic control units are configured to
calculate the maximum oxygen storage capacity of the catalyst based on the amount of oxygen stored in the catalyst when the target air-fuel ratio is maintained at the lean set air-fuel ratio in the oxygen amount variation control and an amount of oxygen released from the catalyst when the target air-fuel ratio is maintained at the rich set air-fuel ratio in the oxygen amount variation control,
determine that the catalyst is abnormal when the maximum oxygen storage capacity is less than a predetermined threshold, and
determine that the catalyst is abnormal when the maximum oxygen storage capacity is equal to or higher than the threshold and a ratio of a period during which the air-fuel ratio detected by the air-fuel ratio sensor is maintained near the stoichiometric air-fuel ratio to a period during which the target air-fuel ratio is maintained at the rich set air-fuel ratio in the oxygen amount variation control is less than a predetermined value.