A study on the indirect urea dosing method in the Selective Catalytic Reduction system

Scientific Conference on Automotive Vehicles and Combustion Engines 2016

Brzezaski, M.^1 ; Sala, R.^2

Institute of Automobiles and Internal Combustion Engines, Cracow University of Technology, Al. Jana Pawla II 37, Krakow

31-864, Poland^1

Automotive Research and Development Institute Ltd, BOSMAL, ul. Sarni Stok 93, Bielsko-Biala

43300, Poland^2

关键词: Engine operations;    Equivalence ratios;    Exhaust gas streams;    Measured results;    Regular solution;    Scientific researches;    Selective catalytic reduction systems;    Wide temperature ranges;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/148/1/012062/pdf
DOI  :  10.1088/1757-899X/148/1/012062

来源: IOP

【 摘 要 】

This article presents the results of studies on concept solution of dosing urea in a gas phase in a selective catalytic reduction system. The idea of the concept was to heat-up and evaporate the water urea solution before introducing it into the exhaust gas stream. The aim was to enhance the processes of urea converting into ammonia, what is the target reductant for nitrogen oxides treatment. The study was conducted on a medium-duty Euro 5 diesel engine with exhaust line consisting of DOC catalyst, DPF filter and an SCR system with a changeable setup allowing to dose the urea in liquid phase (regular solution) and to dose it in a gas phase (concept solution). The main criteria was to assess the effect of physical state of urea dosed on the NOx conversion ratio in the SCR catalyst. In order to compare both urea dosing methods a special test procedure was developed which consisted of six test steps covering a wide temperature range of exhaust gas generated at steady state engine operation condition. Tests were conducted for different urea dosing quantities defined by the a equivalence ratio. Based on the obtained results, a remarkable improvement in NOx reduction was found for gas urea application in comparison to the standard liquid urea dosing. Measured results indicate a high potential to increase an efficiency of the SCR catalyst by using a gas phase urea and provide the basis for further scientific research on this type of concept.