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Experimental studies on the diesel engine urea-SCR system using a double NOx sensor system

  • Tang, Wei (School of Automotive and Traffic Engineering, Jiangsu University) ;
  • Cai, Yixi (School of Automotive and Traffic Engineering, Jiangsu University) ;
  • Wang, Jun (School of Automotive and Traffic Engineering, Jiangsu University)
  • Received : 2015.08.19
  • Accepted : 2015.11.06
  • Published : 2015.12.31

Abstract

SCR has been popularly approved as one of the most effective means for NOx emission control in heavy-duty and medium-duty vehicles currently. However, high urea dosing would lead to ammonia slip. And $NH_3$ sensor for vehicle emission applications has not been popularly used in real applications. This paper presents experimental studies on the diesel engine urea-SCR system by using a double NOx sensor system that is arranged in the downstream of the SCR catalyst based on ammonia cross-sensitivity. It was shown that the NOx conversion efficiency rised as $NH_3/NOx$ increases and the ammonia slip started from the $NH_3/NOx$ equal to 1.4. The increase of temperature caused high improvement of the SCR reaction rate while the space velocity had no obvious change. The ammonia slip was in advance as catalyst temperature or space velocity increase and the ammonia storage reduced as catalyst temperature or space velocity increase. The NOx real-time conversion efficiency rised as the ammonia accumulative storage increase and reached the maximum value gradually.

Acknowledgement

Supported by : National Natural Science Foundation of China

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