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디젤기관의 EURO-6 배기규제 대응을 위한 Urea-SCR 모델의 NOx 및 NH₃ 배출 특성 연구
서준협(Junhyeop Seo),이성욱(Seangwock Lee),조용석(Yongseok Cho),강연식(Yeonsik Kang) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
The Selective Catalytic Reduction(SCR) system is a highly-effective device for NOx reduction of diesel engines. Generally, the ammonia(NH₃) was generated from reaction mechanism of urea solution in the SCR system using the liquid urea as the reductant. Therefore, the precise urea dosing control is a very important factor for reducing NOx and NH₃ slip in the SCR system. In this study, same exhaust gas composition was used in the rig test bench according to exhaust gas temperature and space velocity to analyze characteristics of NOx and NH₃. Parameter indentification of the proposed SCR model is performed using the rig-test experimental data sets. Then, simulations are performed to validate the proposed SCR dynamic system. Thus, the results of this study aim at development of SCR control algorithm to maximize NOx reduction efficiency and minimize NH3 slip through urea injection control strategy.
Vibrometer를 이용한 스프링 장력에 따른 Valvetrain 동특성에 대한 시험적 고찰
서준협(Junhyeop Seo),박재형(Jaehyung Park),주진석(Jinseok Choo) 한국자동차공학회 2020 한국자동차공학회 학술대회 및 전시회 Vol.2020 No.11
Today, issue of high fuel efficiency, reduction of exhaust gases and weight highlighted on development trend of Gasoline and Diesel Engine. Therefore it is important to research and development of each part of engine. Valvetrain play an essential part in suction of air and emission of exhaust gas in Internal Combustion Engine and need to maintain stable behavior from idle speed to max speed. Especially, because about 40% of engine friction loss is valvetrain at low speed, friction reduction for reducing fuel efficiency is the most important factor during engine development. For this reason, many experts study improving valvetrain system from camshaft to valve in order that valvetrain operate stable while valve spring load decrease. Especially, Experts have made many attempts to improve contact loss, valve bounce and jumping in high speed. Valve spring has to provide sufficient preload to keep the valve closed on the base circle. Because of high valve back pressures. This function becomes more important at diesel. Also, valve spring has to provide suitable force to balance dynamic load and avoid unstable movement such as valve bouncing, jumping and so on. Thus, the result of this study aim at development of valvetrain maximize friction reduction and minimize unstable valve movement.