Seang-Wock Lee
Kookmin University
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Publication
Featured researches published by Seang-Wock Lee.
international conference on vehicular electronics and safety | 2012
Chulho Choi; Yeonsik Kang; Seang-Wock Lee
In this study, nonlinear model predictive control (NMPC) is proposed for performing emergency collision avoidance maneuvers. NMPC is employed as a high-level controller that simultaneously controls the longitudinal and the lateral vehicle motion. The designed emergency collision avoidance controller considers the constraints of maximum wheel steering angle and maximum acceleration. NMPC predicts vehicle position using open-loop dynamics and calculates the optimized wheel steering control input and acceleration control input. A collision avoidance maneuver that does not consider vehicle dynamics may not avoid obstacles. In the worst case, it may transition into another dangerous situation. The performance of the proposed collision avoidance maneuver is simulated in Matlab/Simulink and CarSim, a realistic commercial simulation software.
ASME 2011 Internal Combustion Engine Division Fall Technical Conference | 2011
Hoin Kang; Jerald A. Caton; Seang-Wock Lee; Seokhwan Lee; Seungmook Oh
LPG (Liquefied Petroleum Gas) has been widely used as an alternative fuel for gasoline and diesel vehicles in light of clean fuel and diversity of energy resources. But conventional LPG vehicles using carburetors or MPI fuel injection systems can’t satisfy the emissions regulations and CO2 targets of the future. Therefore, it is essential to develop LPG engines of spark ignition or compression ignition type such that LPG fuel is directly injected into the combustion chamber under high pressure. A compression ignition engine using LPG is the ideal engine with many advantages of fuel economy, heat efficiency and low CO2 , even though it is difficult to develop due to the unique properties of LPG. This paper reports on numerical and experimental studies related to LPG fuel for a compression ignition engine. The numerical analysis is conducted to study the combustion chamber shape with CATIA and to analyze the spray and fluid behaviors with FLUENT for diesel and LPG (n-butane 100%) fuels. In one experimental study, a constant volume chamber is used to observe the spray formation for the chamber pressure 0 to 3MPa and to analyze the flame process, P-V diagram, heat release rate and emissions through the combustion of LPG fuel with the cetane additive DTBP (Di-tert-butyl peroxide) 5 to 15 wt% at 25MPa of fuel injection pressure. In engine bench tests, experiments were performed to find the optimum injection timing, lambda, COV and emissions for the LPG fuel with the cetane additive DTBP 5 to 15 wt% at 25MPa fuel injection pressure and 1500 rpm. The penetration distance of LPG (n-butane 100%) was shorter than that of diesel fuel and LPG was sensitive to the chamber pressure. The ignition delay was in inverse proportion to the ambient pressure linearly. In the engine bench tests, the optimum injection timing of the test engine to the LPG fuel with DTBP 15 wt% was about BTDC 12° CA at all loads and 1500 rpm. An increasing of DTBP blending ratio caused the promotion of flame and fast burn and this lead to reduce HC and CO emissions, on the other hand, to increase NOx and CO2 emissions.Copyright
International Journal of Automotive Technology | 2014
Yong-Seok Cho; Seang-Wock Lee; Woongchul Choi; Y. B. Yoon
International Journal of Hydrogen Energy | 2012
Seang-Wock Lee; Woongchul Choi; Yong-Seok Cho
Journal of Mechanical Science and Technology | 2011
Seang-Wock Lee; Han-Seung Lee; Young-Joon Park; Yong-Seok Cho
Journal of Mechanical Science and Technology | 2008
Duk-Sang Kim; Young-Joon Park; Seang-Wock Lee; Yong-Seok Cho
International Journal of Automotive Technology | 2010
Seang-Wock Lee; Yong-Seok Cho; Doo-Sung Baik
International Journal of Automotive Technology | 2012
Seang-Wock Lee; Yong-Seok Cho; Woongchul Choi; Jung-Sug Lee; Young-Su Park
International Journal of Automotive Technology | 2017
Dong-Seop Eom; Seok-Ho Kang; Seang-Wock Lee
Journal of Mechanical Science and Technology | 2016
Gi-Young Park; Seok-Ho Kang; Seang-Wock Lee