Model-Based NH3 Slip Detection for SCR + ASC System Control and OBD |
Wan Chuan1, Lou Diming1, Wang Tiantian2 |
1Automobile College, Tongji University, Shanghai 201804, China 2Key Laboratory of Conveyance and Equipment, Ministry of Education, East China Jiaotong University, Nanchang 330013, China |
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Received: May 9, 2024; Revised: June 6, 2024 Accepted: June 12, 2024. Published online: July 29, 2024. |
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ABSTRACT |
Since accuracy and adaptation of the closed-loop control in selective catalytic reduction (SCR) and ammonia slip catalytic (ASC) systems quite depend on the detection of ammonia (NH3), the identification of NH3 slip is important in the above systems. A model-based NH3 slip detection method by a brief dosing-off maneuver is proposed, which is utilizing NOx sensors’ cross-sensitivity between NH3 and NOx. When the operating conditions are suitable, NH3 slip detection function would trigger once the deviation of the DeNOx efficiency calculated by model and by sensor is over a limit. The NH3 slip could be detected when the consumption of NH3 storage exceeded a limit earlier than DeNOx efficiency below a limit. Validation test results showed this NH3 slip detection function can effectively detect the NH3 slip of SCR + ASC system, and immediately send out a NOx slip result if the tailpipe NOx emission exceeds the OBD limit. |
Key Words:
SCR + ASC system · Model · NH 3 storage · NH3 slip · Detection |
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