| 摘要 |
The present invention relates to a rich control method for reducing discharge of NOx in a reducing agent rich control system. The present invention is to provide a rich control method to efficiently reduce the discharge of NOx by controlling a rich level in accordance with the state of an NOx reducing agent. The reducing agent rich control system includes: a front lambda sensor and a rear lambda sensor, which respectively measure an air-fuel ratio on a front end and a rear end of a NOx catalyst; and a control unit controlling the rich level of a reducing agent using signals of the front lambda sensor and the rear lambda sensor, an occlusion amount of NOx, and other driving condition data. The rich control method includes: a step of determining normal finish of rich control after the reducing agent at a predetermined rich level is supplied to the NOx catalyst, using the control unit; and a step of determining deterioration of the NOx catalyst using the control unit when the finish of the rich control is abnormal. |
