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DFSS를 이용한 Diesel Engine의 Idle Combustion Noise 개선
이근봉(Keunbong Lee),장현모(Hyunmo Jang),이상수(Sangsu Lee),이문식(Moonsig Lee) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
Current diesel engines have common rail FIE system, VGT, EGR and swirl to meet stringent emission regulation and comply with customer’s demand like fuel economy and driving pleasure. To optimize these control factors by conventional EMS calibration methods, calibration engineers need a lot of calibration time and efforts. Therefore instead of conventional methods, general DFSS method that has been successfully used on various engineering quality problems was applied in this study. This study is to improve the combustion noise without fuel economy and emissions penalties in idle conditions. After finding the effects of control factors on combustion noise, emissions and fuel economy using DFSS process, the investigated and the optimized control factors were confirmed at 4 kinds of idle operation conditions. The objective of this study was achieved with optimum control factors.
EN50289 동축케이블 전달 임피던스 측정 방법을 이용한 통신 케이블의 차폐 효과 분석
이근봉(Keunbong Lee),장난(Nan Zhang),전지운(Jiwoon Jeon),송승제(Seungje Song),나완수(Wansoo Nah) 한국전자파학회 2014 한국전자파학회논문지 Vol.25 No.11
본 논문에서는 EN50289 규격에 따른 동축케이블의 전달 임피던스 측정을 이용하여 여러 가지 통신 케이블의 차폐 특성을 분석하였다. EN50289 규격에서의 전달 임피던스 측정 방법은 CENELEC(European Committee For Electrotechnical Standardization)에서 규정한 Triaxial 방법이며, IEC Standard 96-1에서 규정한 Triaxial 방법과 달리 측정하고자 하는 동축케이블과 외부 도체의 직경에 관계없이 동축케이블의 전달 임피던스를 측정할 수 있는 장점이 있다. 본 논문에서는 EN50289 규격에 따른 동축케이블의 전달 임피던스 측정장치를 설계/제작하였으며, 이것을 이용한 실험 결과를 통해 측정 시스템의 신뢰할만한 주파수 대역을 결정하였고, 동축케이블의 쉴딩 기법의 차이에서 오는 영향에 대하여 분석하였다. 전달 임피던스 측정 결과, 케이블의 쉴딩 기법에 따라 전달 임피던스의 상당한 차이가 있음을 보였다. 또한, RG-58 통신용 케이블의 전달 임피던스 이론식에 의한 계산값과 측정값의 비교를 통하여 측정된 데이터가 유효함을 보였다. In this work by measuring transfer impedance of communication cables using EN50289 its Shielding effect is analyzed. transfer impedance measurement triaxial method using EN50289 is defined in CENELEC, it is unlike triaxial method prescribed in IEC Standard 96-1, can be measured regardless of diameter of coaxial cable and outer conductor. in this paper, transfer impedance measurement device of coaxial cable is designed and made according to EN50289 standard, The analysis determines the reliable working frequency range of coaxial cable and examined the impact of different shielding methods on coaxial cable. The transfer impedance measurements show considerable variations in results with various shielding methods. also the measurement procedure is verified through comparison of calculated and measured transfer impedance of RG-58 cable.
Transient Engine Test Bed를 이용한 가솔린엔진의 F/E 및 Emission개선에 관한 연구
이상수(Sangsu Lee),이창준(Changjun Lee),이근봉(Keunbong Lee),이문식(Moonsig Lee),이정근(Jeongkeun Rhee) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The fuel economy and emissions in a developing port injection gasoline engine with manual transmission were studied using a transient engine test bed. Because the fuel economy and emissions in the first few minutes during engine warmup show great importance, the first ECE cycle in NEDC mode was simulated. To match the fuel economy and emission levels with the roller bed test results, driver model on clutch and acceleration pedal actions were thoroughly adjusted to match engine speed and engine load of the vehicle. The faster catalyst light-off was investigated by varying crank-to-run air-fuel ratio and idle spark timing. and results showed that slightly lean air fuel ratio was more effective in heating lip the catalyst than retarding idle spark timing in terms of fuel economy. The additional engine EMS calibrations were performed to improve cruise operation points and idle regions using DOE method with L9 orthogonal test array. The overall results showed that both the fuel economy and emissions were improved during first ECE cycle in the NEDC mode test by the EMS calibration performed in this study.
Dynamic Engine Test Bench를 이용한 가솔린 차량의 Emission Test에 관한 연구
이상수(Sangsu Lee),이근봉(Keunbong Lee),이문식(Moonsig Lee),김숭기(Soongkee Kim) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
The fuel consumption and emissions from gasoline vehicle with MT and AT were tested using a dynamic engine test bench. The engine was dynamically controlled to simulate the dynamic behavior of engine inside the vehicle in motion. The variation of EMS data in vehicle such as engine speed, MAP and gear stage was closely reproduced with engine test bench by using inertia simulation and control software and found to reproduce fuel economy around ±1%, and emissions around ±10%. The forced soaking procedure, signal generator for TCU, realistic coolant temperature profile and idle MAP increased by dyno friction were tried for better correlation with vehicle data.
인터리브드 RPWM Buck 컨버터의 전도성 노이즈 감소에 대한 연구
이승현(Seunghyun Lee),이근봉(Keunbong Lee),나완수(Wansoo Nah) 한국전자파학회 2017 한국전자파학회논문지 Vol.28 No.4
본 논문에서는 DC-DC Converter에서의 고조파로 인한 전자기적 잡음을 줄이기 위해 Random PWM을 적용한 Interleaved Buck Converter(IBC) 시스템을 제안한다. PWM 직류전원장치에서 스위칭 방식을 사용하는 경우 스위칭 손실 및 EMI 문제가 발생하기 때문에 많은 고조파를 포함하고 있어 선간 전압의 왜곡 등을 유발한다. 따라서 이에 대한 해결방법으로 PRBS를 이용한 IBC를 최초로 제안한다. 이 방식의 회로 구조는 2개의 능동형 스위치를 가지며 180도의 위상차를 갖는 2개의 PWM 신호를 이용하여 회로를 제어한다. IBC는 1세트의 스위치를 추가하기 때문에, 비용 측면 등에서는 불리 할 수 있으나 전력분배, 출력전류 리플 감소, 빠른 회로 반응속도, 수동소자크기 감소의 이점을 가진다. 본연구의 타당성을 확인하기 위하여 PSIM 시뮬레이터를 이용하였고 Random PWM을 적용한 IBC 회로를 설계하여 기존의 PWM과 RPWM 방식만을 사용하는 Buck-converter 회로를 PSIM 시뮬레이터를 이용하여 결과를 확인하고 분석하였다. This paper presents a Interleaved Buck Converter(IBC) system with Random PWM to reduce electromagnetic noise by harmonics. Swithced mode power supply generally controlled by high switching frequency have a electromagnetic interference(EMI) issue due to the high-voltage/high-current switching to regulate the voltage in buck converter. To solve the problem. we present a novel IBC system with PRBS. IBC system has two active switches with 180 phase difference that controll the cicuit with two PWM signal. IBC system may be disadventageous for the cost due to the addtion of one set of switch, but it has adventages of power distribution, current ripple cancellation, fast transient response, and passive component size reduction. To verify the validity of study, simulation program has been bulit using PSIM and the experimental results of IBC system using RPWM was compared with the conventinal PWM and randomized PWM.
Post Injection을 이용한 Diesel Engine의 Turbo Lag개선 및 가속성능 향상
윤동필(Dongpil Yoon),박상운(Sangun Park),이근봉(Keunbong Lee),박영현(Younghyun Park),김숭기(Soongkee Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Growing concern about increasing greenhouse gases (GHG) today, automobile industry is highly requiring stricter emission regulations and improved fuel consumption. It means that engine development should be more focused on a high efficiency and small displacement engine. To achieve for this demand, one of the effective method is reduction of the engine size by using a turbocharger or supercharger. Turbocharged boost technologies are able to increase thermal efficiency. However, the turbocharged downsized engines generally have worse response than the naturally aspirated (NA) engines because it takes a few seconds to get the turbocharger rotate up to high speed, usually called "Turbo-lag". In order to solve this matter, one possible way is hard solution: some changes in intake/exhaust layout and turbo inertia can be considered, or more sophisticated systems such as a two-stage turbocharger or a supercharger. Different way is soft solution to avoid it: some variables to control the turbocharging systems are optimized. This paper deals with the transient response of a common rail diesel engine with variable geometry turbocharger (VGT). In the paper, a DFSS method was used and also analyzed each factor which influence to turbo lag. The researches discussed focused on soft solution from the result of this analysis. The control strategy is based on the optimization of post injection with conventional VGT control at various transient engine conditions. Also, we developed the algorithm of driver’s intention to accelerate rapidly based on the driver demand. Reflecting driver’s intention selectively, the control strategy for transient response is capable of improving the vehicle acceleration performance with minimum deterioration of total smoke emissions and fuel consumption during the sudden acceleration.