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[연료 및 윤활유부문] 고차스펙트럼 해석법을 이용한 비선형 기계적 시스템에 관한 연구
이준서(Joonseo Lee),차경옥(Kyungok Cha) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In this paper higher order spectral techniques are applied to some simple mechanical systems. The system studied is the nonlinear magnetic beam. This is a simply supported beam, driven by an electromagnetic shaker. At the free end, .pairs of repelling magnets are placed. By varying the position and number of magnets, the nature of the nonlinearity can be changed, be it skewed or symmetric, and by varying the distance between the magnets the strength of the nonlinearity can also be altered. Using this controllable system, auto higher order spectral methods are applied, assuming only a knowledge of an output signal.
[진동·소음부문] 자동차 배기계의 능동형 제어 머플러 개발에 관한 실험적 고찰
이해철(Haechul Lee),차경옥(Kyungok Cha) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This study is on the development of a new muffler composed of a valve system using an elasticity of spring. The valve system using the elasticity of spring is set along the exhaust-gas flow and designed to work itself alone the driving condition of a engine. By that reason, the engine capacity is so enlarged that a muffler with controller sensing exhaust-gas pressure is able to be satisfied to noise reduction and power enlargement more than conventional muffler. The purpose of this study is to develope the new muffler which has more noise reduction and power enlargement than conventional muffler and electric-control muffler.
단기통엔진에서의 GTL(Gas-To-Liquid) 연료특성 연구
김동희(Donghee Kim),이용규(Kyungok Cha),최교남(Yonggyu Lee),정동수(Kyonam Choi),차경옥(Dongsoo Jeong) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_1
Recently, alternative fuels are drawing more attentions due to the increasing need for lower emission characteristics and fuel consumption rate in automotive engine. The GTL(gas to luquid) is the one of most favored candidates. GTL is a synthetic liquified fuel made from natural gas or charcoal with Fischer-Tropsch mechanism. It has higher cetane number(more than 75) and almost negligible sulphur and aromatic contents. Therefore, enhanced emission characteristics are expected even in the application in diesel engines without any modification. In this study, the engine performances and emission characteristics are compared between diesel and GTL fuel in the single cylinder diesel engine. Also the various blendings between Diesel and GTL(30%, 50% in volume) are also tested to investigate optimal blending ratio in the respect of emission characteristics. Noticeable reduction in soot, THC and CO emission are observed without the loss of engine power due to low sulphur and aromatic contents in GTL. Also, the ignition delay decreased due to higher cetane number of GTL, which slightly decreased the amount of NOx emissions.
이민호(Minho Lee),차경옥(Kyungok Cha),조규백(Gyubaek Cho),최교남(Kyonam Choi),정동수(Dongsoo Jeong) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.5_1
In the future, automotive engine should satisfy the more stringent CO₂emission regulation without trading off the higher thermal and combustion efficiencies. Natural gas is one of the most promising alternative fuels for automotive engine, because it can reduce exhaust gas emissions than gasoline, diesel and LPG fuel, and can be used in conventional engines with a little modification. But, the performance of natural gas engine is fewer than gasoline, diesel and LPG fuel engine. Therefore, natural gas engine is requires a different methods for the improvement of engine characteristics such as engine power, fuel economy, brake thermal efficiency and exhaust gas emissions. Low compression, high expansion ratio could be one of the solutions in this context, which can be realized in automotive engines by making the expansion period longer than compression period.<br/> The objective of this study is to examine the effect of low compression, high expansion ratio on engine characteristics such as engine power, fuel economy, brake thermal efficiency. To realize low compression, high expansion ratio in engines, intake valve timing was varied by applying several cam-shafts with different cam profiles. Also a supercharger was adopted to increase the power. These experiment results may be utilized to develop natural gas engine of high efficiency and low emissions for automotive.
[디젤엔진부문] 터보과급 디젤엔진의 성능 및 배기가스특성에 관한 연구
윤준규(Junkyu Yoon),차경옥(Kyungok Cha) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The characteristics of performance and exhaust emission in a turbocharged D.I. diesel engine was studied experimentally in this paper. The system of intake port, fuel injection and turbocharger are very important factors which have influence on the engine performance and exhaust emission because the properties in the injected fuel depend on the combustion characteristics.<br/> The optimum results which is tested as available parameters for better performance and emission are as follows; the swirl ratio is 2.43, injection timing is BTDC 13' CA, compression ratio is 16, combustion bowl is re-entrant 5' , nozzle hole diameter is ?? 0.28*6, turbocharger is GT40 model which are compressor A/R 0.58 and turbine A/R 1.19.<br/>
내부 EGR 효과를 이용한 활성화학종에 의한 급속연소 특성
이진수(Jinsoo Lee),차경옥(Kyungok Cha),최수진(Sujin Choi),조규백(Gyuback Cho),정동수(Dongsoo Jeong) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Exhaust gas emissions from internal combustion engines are one of the major sources of air pollution. It is extremely difficult to increase gasoline engine efficiency and to reduce simultaneously NOx and PM(particulate matter) in diesel combustion.<br/> This paper offers some basic concepts of overcoming the above problems. To solve the problems, a recommended technique is CAI(controlled auto-ignition) combustion. The internal EGR(exhaust gas recirculation) effect is suggested to realize CAI combustion.<br/> Thus, an experimental study was carried out to achieve internal EGR using homogeneous premixed gas mixture in the constant volume combustion chamber(CVCC). Moreover, two kinds of obstacles were used to simulate internal EGR effect. Flame propagation photos and pressure signals were acquired to verify internal EGR effect. Hole type obstacle creates high speed burned gas jet. It achieves the highest flame propagation speed due to the effect of geometry and burned gas jet. Double mesh type was also found to increase flame propagation speed.
이민호(Minho Lee),차경옥(Kyungok Cha),최교남(Kyonam Choi),조규백(Gyubaek Cho),정동수(Dongsoo Jeong) 한국자동차공학회 2002 한국자동차공학회 Symposium Vol.2002 No.11
GHP, operated by gas engine instead of electrical motor, has there is better energy saving 20% comparing with<br/> EHP(electrical motor-driven heat pump) by using the exhaust heat from the engine effectively. This means that GHP<br/> has an advantage in the reduction of CO2 which causes main greenhouse effects.<br/> Natural gas engine for GHP should be mostly based on 4 stroke water-cooled diesel engine which has high power<br/> in low speed, but sometimes could be based on automotive LPG engines because of easy modification.<br/> In this paper, experimental study for the improvement of both thermal efficiency by exhaust heat and emission<br/> reduction has been conducted by using catalyst and SAI systems in case of the conversion of an automotive LPG<br/> engine into GHP natural gas engine.