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이원근(Wongeun Lee),임효재(Hyojae Lim) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
A parametric study was conducted on pressure drop in a catalytic converter for automobile. In this work, we proposed a new pressure drop relation which contains the various parameters needed to calculate and got a few results. In a monolith of catalyst, the flow originally turbulent flow changes to laminar flow and thus the pressure drop through the monolith is linearly proportional to the velocity. The exhaust pressure is doubly affected by the increase of mean velocity and length when we decrease the diameter of monolith while the volume keeps constant. Theoretical parameters such as ?? and β are suggested to use as a reference value when there is no a experimental data. Especially in the part load test, these values should be modified to consider the property change of exhaust gas.<br/>
흡배기 밸브타이밍이 가솔린엔진의 부분부하 성능에 미치는 영향
이원근(Wongeun Lee),한봉훈(Bonghoon Han),김우태(Wootai Kim) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The potential benefit of dual CVVT was investigated by changing the exhaust valve timing in an intake CVVT engine. Intake/exhaust valve timing affects greatly on the part load performance by the combined effect of increased overlap, late intake valve closing timing, and park load knocking tendency. Pumping loss was reduced more effectively by exhaust cam phasing than intake can phasing. It is shown that there are many additional benefits of both intake/exhaust cam phasing over intake cam phasing only. Brake specific fuel consumption level was improved by about 2%, and addition reduction of about 30% in NOx emission was observed due to increased internal exhaust gas recirculation. Some potential reduction of hydrocarbon emission was also observed.
배기계 내구시험 중의 온도변화 simulation process 개발
이원근(Wongeun Lee),박상준(Sangjoon Park),한봉훈(Bonghoon Han),김우태(Wootas Kim) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Exhaust manifolds suffer from serious temperature variation during the thermal fatigue test. The spatial <br/> distribution of temperature changes at each moment Because transient flow can not be simulated during the long period of temperature change, the simulation can not be conducted by conjugate heat transfer analysis. In this study, a new procedure for transient thermal analysis is established by decoupling fluid-solid analysis. The procedure consists of (l) transient CFD calculation (2 cycle), (2) mapping heat transfer coefficient as a B.C of head conduction analysis and (3) transient heat conduction analysis in the long period (30 min). The realistic temperature change can be predicted by this procedure.<br/>
김용래(Yongrae Kim),이경현(Kyeonghyeon Lee),민경덕(Kyoungdoug Min),이원근(Wongeun Lee),김홍집(Hongjip Kim) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Simulation of CAI engine was conducted in an single cylinder engine which was modified for CAI combustion. Result of CFD calculation including a direct injection during underlap provided that the mixture concentration around intake valve close had a uniform distribution. A reduced chemical kinetic mechanism was used for gasoline fuel and initial conditions (EGR and temperature) were acquired from 1-D cycle simulation. The simulation results showed that CAI combustion was occurred at the temperature of 970 K ~ 1000 K and the pressure of around 15 bar. The EGR rate had an important role for high temperature mixture but the temperature in itself was more critical for the induction of CAI combustion. EGR and mixture temperature could be adjusted by an variation of valve lift and timing.