| 摘要 |
The catalyst monitoring method involves sensing the switching rate of a first upstream exhaust gas oxygen sensor, and disabling the catalyst monitoring function when exhaust gas oxygen sensor switching of the first upstream exhaust gas oxygen sensor is below a minimum threshold value. The number of exhaust gas oxygen sensor switches for the first upstream and second downstream sensors for a specified mass air flow condition are recorded when the first upstream exhaust gas oxygen sensor is switching above the minimum threshold value. The method also involves determining a ratio indicating catalyst hydrocarbon processing efficiency by dividing the number of second downstream exhaust gas oxygen sensor switches by the number of first upstream exhaust gas oxygen switches after a specified number of first upstream exhaust gas oxygen switches have been recorded. A fault is indicated when the exhaust gas oxygen switch ratio exceed a specified value. |
