배압 계산시 압력계수의 영향 연구

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/>

포트 마스킹이 엔진의 부분부하 성능에 미치는 영향:Part I - 희박연소 한계

이원근(Wongeun Lee),엄인용(Inyong Ohm) 한국자동차공학회 2001 한국 자동차공학회논문집 Vol.9 No.5

This paper is the first of companion papers, which investigate port-masking effects on lean misfire limit. Port-masking was applied to commercial SOHC 3-valve and OOHC 4-valve engine by inserting masking plates between manifold and port. To induce various conditions of stratification, six types of masking plates were applied. The masking plates were placed in the upstream of injector to prevent wall wetting and two ports were not separated to permit both fuel and air entering through masked port. The results were compared with those by conventional port throttling.<br/> The results show that lean misfire limit mainly depends on masking direction, that is, high lean misfire limit is achieved when the port near the spark plug is masked. The mechanism of stratification by masking is different from axial stratification by port throttling. In this case, the rich mixture entering through masked port plays a very important role in the stratification process.

가솔린 엔진에서 압축비 변경 방법이 성능에 미치는 영향

이원근(Wongeun Lee),엄인용(Inyong Ohm) 한국자동차공학회 2001 한국 자동차공학회논문집 Vol.9 No.4

In this study, it is observed that the distribution of combustion chamber volume affects the volumetric efficiency. The distribution ratio was adjusted by controlling combustion chamber volume of head and piston bowl one. Four cases were investigated, which are the combination of different distribution ratios and different compression ratios (9.8-10.0). A commercial SOHC 3-valve engine was modified by cutting the bottom face of the head and/or replacing the piston by the one that has different volume.<br/> The result shows that the less the head side volume, the more volumetric efficiency is achieved under the same compression ratio. It is also observed that increasing volumetric efficiency results in early knock occurrence due to increased real compression ratio. To consider reliability in estimating the volumetric efficiency, we examined the sensitivity of the AFR equation to possible errors in emission measurements. It is shown that the volumetric efficiency, which is calculated by measuring AFR and fuel consumption, can be controlled in 1 % error.<br/>

촉매를 고려한 배압 계산에서의 인자 결정 연구

이원근(Wongeun Lee),임효재(Hyojae Lim) 한국자동차공학회 2003 한국 자동차공학회논문집 Vol.11 No.5

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 a 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/>

Youtube API를 활용한 데이터 분석, 저장 웹 서비스

이성원(Lee Seongwon),이원근(Lee Wongeun),이지혁(Lee Jihyeok),박진산(Park Jinsan),천용태(Cheon Yongtae) 한국정보기술학회 2023 Proceedings of KIIT Conference Vol.2023 No.6

경험적 분포함수의 통계량을 이용한 확률분포형의 결정

신홍준(Shin Hongjoon),이원근(Lee Wongeun),허준행(Heo Jun-Haeng) 대한토목학회 2009 대한토목학회 학술대회 Vol.2009 No.10

흡배기 밸브시기 동시 변경이 SOHC SI 엔진성능에 미치는 영향

엄인용(Inyong Ohm),이원근(Wongeun Lee) 한국자동차공학회 2003 한국 자동차공학회논문집 Vol.11 No.6

Variable valve timing(VVT) mechanisms are used widely for improving fuel consumption and reducing emissions. Most of application, however, are limited in the DOHC engine. Dual equal retard/advance strategy is relatively simple one and can be applied to both SOHC and DOHC engines. In this study, effects of dual equal valve timing retard/advance are investigated to observe the feasibility of VVT system on an SOHC SI engine. The result shows that fuel economy and emissions are improved in the dual retard condition due to increased internal EGR. Some amount of increase in volumetric efficiency can be achieved by advancing valve timing at low speed and by retarding at high speed. In this case, however, full load power is not so much improved as the volumetric efficiency increases because of severe knock. In the dual advance condition, there is no merit in the fuel economy and emission.<br/> <br/>

축소화학반응식을 이용한 CAI 엔진의 연소특성 해석

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.