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LPL EGR System 적용 대형 디젤엔진의 EURO-5 NOx 규제대응에 관한 연구
이교승(Kyo Seung Lee),박형배(Hyung Bae Park) 한국동력기계공학회 2006 한국동력기계공학회 학술대회 논문집 Vol.- No.-
Recently, many small and midium size diesel vehicles are have equipped turbocharger to get high performance and EGR system to reduce NOx emissions but its application to heavy-duty diesel engine is not common yet. In this work, the simulation model for EURO-3 engine was developed using WAVE and then its performance and emission level were verified by comparing with experimental results. The possibility of current EURO-3 engine with LPL EGR system satisfying the EURO-5 regulation would examine. ESC 13 mode was chosen as the primary engine test mode, and the injection timing and fuel quantity were changed to compensate the lost engine performance caused by EGR. The system developed in this study shows that the current EURO-3 engine could satisfy EURO-5 NOx regulation by applying LPL EGR.
논문 : 응고 ; 주조과정에서의 유동 및 열전달현상에 관한 수치적 연구
이진호 ( Jin Ho Lee ),목진호 ( Jin Ho Mok ),이교승 ( Kyo Seung Lee ) 대한금속재료학회 ( 구 대한금속학회 ) 1996 대한금속·재료학회지 Vol.34 No.11
Numerical analysis is made to see how to control the defects caused by fluid flow and solidification in the casting process. With SIMPLER algorithm the Marker Method that is induced in the MAC or SMAC method has been adopted to analyse the behavior of the free surface in the mold. The normal and the tangential stress condition have been used as free surface boundary conditions. The flow field and thermal behavior is investigated from the start of the filling process to the final solidification. The flow is assumed to be 2-D, incompressible, and laminar, and the material is pure aluminium. Calculation domain was organized on the basis of the staggered mesh generation. For one model, different inlet condition has been applied to estimate the flow, solidification, the free surface position, and the phase change surface motion. This result is helpful to find the most desirable mold design.
2영역 모델을 이용한 EGR사용 직접분사식 디젤엔진의 Nox생성예측
김철환,이진호,전광민,이교승,Kim, Cheol-Hwan,Lee, Jin-Ho,Chun, Kwang-Min,Lee, Kyo-Seung 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.3
In this study, numerical calculation is carried out to investigate the influence of injection timing, fuel amount, intake $O_2$ concentration, and EGR on Nitric Oxide(NO) formation using a two-zone model in a diesel engine. Results can be summarized as follows. The NO formation is very sensitive to the burned gas temperature, so multi-zone model must be applied to combustion process to predict the burned gas temperature exactly. Since the burned gas temperature increases rapidly during the premixed combustion, most NO is formed within 20 crank angle degrees after ignition. As the injection timing is retarded, the combustion occurs later in the expansion process which causes the decrease of burned gas temperature and, as a result, NO formation decrease. The increase of fuel amount results in the increase of earlier formation of NO in the engine. As the intake $O_2$ concentration increases, the maximum pressure and burned gas temperature increase due to activate combustion. And, [O] mole fraction of equilibrium combustion products also increase. Therefore NO exponentially increases. If exhaust gas is recirculated, the burned gas temperature decreases which results in NO decrease. If exhaust gas is cooled, more NO can be decreased.
박성준(Sung-Jun Park),이교승(Kyo-Seung Lee),남궁재관(Chai-Kwan Namkoong) 한국생산제조학회 2005 한국생산제조학회지 Vol.14 No.3
A new measuring method for tool deflection has been developed when sculptured surface is processed in ball-end milling. Since the vibration due to cutting forces has low frequencies, an electromagnetic sensor is used for measuring the exact vibration displacement. The amplitude and direction of vibration displacement during the cutting process is presented as orbital plot. In this study, it assumes that the vibration displacement is proportional to the length of cutting chip. Therefore, tool deflection is calculated by summing up the vibration displacement of unit chip length for engaged chip length. In addition, computer programs has been developed to predict the deflection of tools when machining sculptured surface. This developed program predicts the tool deflection per block of NC data, so that it can easily identify the parts which have the possibility of machining errors.