| 摘要 |
PURPOSE: A catalyst diagnosis system and method for a vehicle are provided to distinguish the deterioration of catalyst by diagnosing the reduction in oxygen storage capacity of a catalyst. CONSTITUTION: A catalyst diagnosis system for a vehicle comprises a catalyst(200), first and second oxygen sensors(210,220), and a controller(300). The catalyst purifies exhaust gas through oxidation and reduction. The first and second oxygen sensors are respectively installed in the upper stream and downstream sides of the catalyst and sense the density of oxygen according to lean/rich transition of air-fuel ratio. The controller detects the oxygen storage capacity of the catalyst in an idle condition and compares it with the critical value in order to determine the contamination of the catalyst. |
