| 摘要 |
PURPOSE: An exhaust gas purifying method for a vehicle is provided to improve the exhaust gas purifying efficiency by carrying out the transition of an air-fuel ratio of an engine to a concentrated air-fuel ratio if a total discharge amount of NOx exceeds an occlusion capability of an occlusion type catalyst converter due to a long time lean burn of the engine. CONSTITUTION: An exhaust gas purifying method for a vehicle includes the steps of recognizing an amount of NOx able to be occluded in an occlusion type catalyst converter by test and recognizing a discharge amount of NOx according to an air amount in a lean burn area, determining whether a total discharge amount of the NOx in the continuous lean burn of an engine exceeds an occlusion capability of the occlusion type catalyst converter by an electronic control unit(ECU), and lowering an air-fuel ratio of the engine to a concentrated air-fuel ratio by the ECU if yes.
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