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냉각 시스템 제어에 따른 디젤 엔진의 배기가스 저감에 관한 연구
최경욱(Kyungwook Choi),조원준(Wonjoon Cho),이기형(Kihyung Lee) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
These days the exhaustion of petroleum resources and environmental problems are getting serious. Many researchers are focused on low emission and high performance vehicles. Therefore, we should concern about emission regulation when we design a new car. In this study, we investigated the characteristics of the traditional mechanical engine cooling systems which control the engine temperature using engine speed and wax type thermostat. This experiment used three components which are Radiator fan, water pump and water valve controlled by an electronic system based on the engine status (load, speed). We elucidated how different between traditional mechanical cooling system and electronic cooling system which control coolant temperature and coolant flow rate in a DI diesel engine in this paper. The results revealed a fuel saving and an emission (CO, HC) reduction on NEDC cycle.
EGR gas 온도에 따른 디젤 엔진의 연소 특성에 관한 연구
최경욱(Kyungwook Choi),문병헌(Byungheun Moon),김기범(Kibum Kim),이기형(Kihyung Lee) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.41
To satisfy stringent regulations on CO2 emission causing greenhouse effect automotive manufacturers have recently paid attention on a diesel engine. In this paper, low temperature cooling circuit strategy was proposed to control EGR gas temperature and charged air temperature. The cooling system in a High Speed Direct Injection Diesel Engine was modified for the purpose of this study and the strategy was tested in a stationary test bench. As a result, temperature of the coolant passing through EGR cooler could be decreased leading to increase in charging efficiency of EGR gas. Emission and Fuel consumption were improved by controlling the EGR gas temperature.
가솔린 엔진용 배기 폐열 회수 시스템의 효율 향상을 위한 연구
차원심(Wonsim Cha),최경욱(Kyungwook Choi),김기범(Kibum Kim),이기형(Kihyung Lee) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
In recent, there are tremendous efforts to apply co-generation concept in automobile to improve its thermal efficiency. The co-generation is basically a simple Rankine Cycle that uses the waste heat from the engine exhaust and coolant for heat source. In spite of developed NANO technology and advance material science, the bulky co-generation system is still a big concern in automotive application. Therefore, the system should be effectively designed not to add much weight on the vehicle, but the capacity of the waste heat recovery should be still large. With such a goal in mind, the system thermal efficiency was investigated in terms of the system operation condition and working fluid. This paper provides a direction for the optimal design of the automotive co-generation system.
Engine Warm-up 기간의 Zero Coolant 적용에 관한 연구
조원준(Wonjoon Cho),최경욱(Kyungwook Choi),김형익(Hyungik Kim),이기형(Kihyung Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Recently, there has been an interest in intelligent cooling system as it has the potential of achieving a better fuel economy and emission reduction. It is possible mainly due to the higher coolant temperature during engine warm-up and low speed/part-load conditions. Thus the purpose of our study was to investigate the relationship between zero coolant strategy and fuel consumption. A coolant flow test system was set for acquisition of coolant flow rate, pressure distribution and coolant temperature. Thease results were used for experimental data to validate the 1-D CFD code, Flowmaster2. From this study, we found that the zero coolant strategy improved fuel economy and emission reduction on the engine warm-up, and this results can be used for engine cooling system simulation model.
1D simulation을 이용한 랭킨 사이클 폐열 회수 시스템 성능 분석
이재민(Jaemin Lee),최경욱(Kyungwook Choi),이기형(Kihyung Lee) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5
Waste heat recovery from rejected energy of automotive engine is one of the most effective technique to improve thermal efficiency. In this paper, Organic Rankine Cycle (ORC) for waste heat recovery was investigated by using AMESim, 1D simulation tool. In particular, as mass flow rate of working fluid is varied, characteristics of ORC were evaluated. The data need to 1D simulation are acquired from experimental result. To increase quantity of waste heat recovery, ORC is composed of a high temperature loop (HT Loop) that recovers the waste energy of exhaust gas and a low temperature loop (LT Loop) that recover the waste energy of coolant. Consequently, when mass flow rate of working fluid was decreased, maximum temperature and maximum pressure in the ORC were increased. From this result, we found that this phenomenon affected an efficiency and power of ORC.
자동차 냉각 성능 향상으로 인한 배기 및 연비 저감에 대한 연구
문병헌(Byungheun Moon),이기형(Kihyung Lee),김기범(Kibum Kim),최경욱(Kyungwook Choi) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
The automotive cooling inventory is normally designed such that it can endure the excessive heat load situations that occur sporadically. Considering most normal driving modes, the cooling systems are unnecessarily large, which increases harmful emissions and fuel consumption of vehicles. An experimental study was carried out to evaluate a novel automotive cooling strategy using the latent heat of a phase change material (PCM) that made it possible to downsize the automotive engine cooling system. The heat load averaging capability of the PCM led to around 35% decrease in cooling system, and the engine warm-up time reduced around 60% as a result of downsizing the cooling system. In addition, severe coolant temperature shaking was successfully averaged out in the downsized cooling system with a heat accumulator containing PCM. This innovative cooling concept will definitely contribute to a considerable improvement in terms of fuel economy and emissions characteristics of vehicles by achieving stable combustion condition of engines as well as reducing total body weight. The more detailed discussion will be presented in the manuscript.
물리 모델 기반 1D 비정상상태 엔진 해석 기술 개발 및 적용 : G90 가솔린 3.5 터보 48V e-S/C
이동규(Dongkyu Lee),김지호(Jiho Kim),장원욱(Wonwook Jang),박종일(Jongil Park),남혜동(Hyedong Nam),최경욱(Kyungwook Choi) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11
Physical model based 1D engine transient simulation technic was developed in this study. Application to actual development work was regarded as the top priority after analyzing reasons why previous similar approaches had not been utilized in HMC. Transient phenomenon of boost build-up(Turbo-lag) during WOT acceleration for turbo-charged engine was modeled. The existing steady-state model was evolved to transient with minimized modifications. The response delay of actuators was considered as well as simplified ECU for WOT acceleration including scavenging logic. The developed model was validated against detailed measurement data. The technic was applied to RS4 G6DIII 3.5 T-GDi 48V e-S/C acceleration performance improvement. Several H/W layouts and S/W effects were evaluated before prototype design, then improvement direction was proposed.