【摘要】 有效识别出氨（NH₃）泄漏是柴油机NO_x转化（De NO_x）系统实现精确闭环控制与自适应修正的基础．针对NO_x传感器对排气中的NH₃和NO_x存在交叉敏感这一情况，提出了一种基于停喷状态下选择性催化还原（SCR）系统储氨响应特性的NH₃泄漏识别方法．在工况条件合适时，持续将NO_x转化效率的传感器测量值和预测值的比值与标定限值进行对比，超过限值时则触发停喷诊断动作，并在停喷过程中通过对比催化器的储氨消耗超过限值的时间与转化效率低于限值的时间先后，实现对NH₃泄漏状态的准确识别．结果表明：该方法能够有效识别出SCR系统的NH₃泄漏，并能够在NO_x排放超过车载故障诊断（OBD）限值时准确识别出NO_x排放超标．更多还原

【Abstract】 Identification of ammonia（NH₃） slip is important for accurate closed-loop control and self-adaptation of De NO_x systems. A NH₃ slip detection function based on NH₃ coverage changing behavior of selective catalytic reduction（SCR） system under dosing stopped status was proposed based on NO_x sensors’ cross-sensitivity between NH₃ and NO_x. Under suitable operating conditions,once the ratio of the DeNO_x efficiency calculated by the sensor to that calculated by model was over the calibrated limit,the NH₃ slip detection function would be triggered. The NH₃ slip could also be detected if the ammonia consumption became over a limit at the time earlier than the DeNO_x efficiency below a limit. Validation tests results show that this NH₃ slip detection function can effectively detect the NH₃ slip of the SCR system,and can immediately send out a NO_x slip result when NO_x emission exceeds the onboard diagnostics（OBD） limit.更多还原