• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.35-41
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• 2005

The effects of cooled-ECR on the characteristics of combustion and exhaust emissions were investigated in a single cylinder HCCI diesel engine The premixed charge (gasoline or diesel) was obtained with premixing chamber and high-pressure (5.5MPa) injection system. Exhaust pressure control and cooled ECR system were used in order to reduce pressure fluctuation and to mix the exhaust gas well with the fresh intake air. The experimental results show that NOx emissions from conventional diesel engine are steeply decreased by HCCI diesel combustion with cooled-EGR in both case of gasoline and diesel premixing. But soot emissions are rapidly increased with the increase of ECR rate. The recycled exhaust gas increased the ignition delay of mixture and decreased maximum combustion pressure. HC and CO emissions of HCCI combustion are increased with ECR rate.

• Journal of Energy Engineering
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• v.17 no.4
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• pp.212-217
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• 2008

This study carried out the safety evaluation of non-refillable butane can for portable gas range equipped with relief valve for prevention of explosion. The can is heated by electric heater at the real using condition and the extreme condition after installing at a portable gas range for checking the operating pressure and the evaluating suitability of releasing flux. And the possibility of fire or explosion was tested when the gas was released from the relief valve at the real condition. As a result of this safety evaluation test, a non-refillable butane can with relief valve prevents the can from exploding by control of internal pressure.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.108-116
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• 2002

The diesel engine is one of the most effective transport options available in all sizes and covering a wide range of applications. But, many researchers developing the diesel engine are facing tough challenges in view of the increasingly lower emissions standards. Thus, this study will explore the possible fuel additive technology to further reduce the emissions from the IDI diesel engine. The purpose of this study is to investigate the effects of oxygenated fuels on the exhaust emissions and to attain a better trade-off relation between smoke and NOx in four cylinder diesel engine. Experiments were conducted with oxygenated fuels as an effective way to improve the combustion efficiency. Some of oxygenated fuel(Diglyme and DEE) were added to the conventional diesel fuel which had no an oxygen content. Also, EGR was adopted for reducing NOx without any strong adverse effects on other exhaust emissions. This study concluded that exhaust emissions in diesel engine could be reduced by adding the oxygenated fuels which had lower boiling point, and the combustion efficiency was also improved as the oxygen content in fuel increased.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.3
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• pp.99-105
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• 2011

This paper described the effect of the multiple injections on the emission characteristics and combustion stability in a common rail diesel engine. In order to investigate the influence of multiple injections in a passenger car diesel engine, the injection strategy was varied with pilot injection, post injection and one main injection at various conditions. Based on the experimental results, the combustion and emissions characteristics were analyzed for the various injection strategies such as main, pilot-main, double-pilot-main, double- pilot-main-post injection strategy. It is revealed that the $NO_X$, HC and CO emissions are reduced by double pilot and post injection at medium load, however, soot emission is increased. Also, in the case of multiple injection, the combustion pressure is increased smoothly near the TDC and the coefficient of variation and fuel consumptions are decreased.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.4
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• pp.132-139
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• 2010

This paper describes an investigation of the performance and emission characteristics of a commercial cylinder direct injection diesel engine operating on natural gas with pilot diesel ignition. Engine tests for variations in the pilot injection timing were performed at an engine speed of 1500 rpm. This study showed that the performance of the dual-fuel diesel engine increased as the engine load increased and as the pilot diesel injection timing angle advanced. The peaks of cylinder pressure, pressure rise rate, and heat release rate all increased while the fuel ignition timing advanced with the pilot injection timing. The engine operation was stable, and the least smoke was produced at a pilot injection timing of $12^{\circ}$ before top dead center. NOx emissions were only exhausted under high-load conditions, and they increased as the pilot injection timing angle advanced.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.35-41
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• 2003

산업의 고도화 및 도시의 집중화로 오염물질의 종류가 다양화 되었으며 여러 가지 오염물질 중에서도 비산 분진, 황산화물(SOx) 등은 연료 중의 특정성분을 제거하거나 연료를 대체하여 그 배출량을 줄일 수 있다. 그러나 질소산화물(NOx)의 경우에는 연료의 문제가 아니라 연소과정에서 반드시 발생되는 특징을 가진 오염물질이다. 이와 같이 환경오염물질의 제거기술에 있어 가장 중요하게 고려되어야 할 사항은 오염가스 제거의 효율성과 경제성이다. 따라서 본 연구에서는 사무실, 가정 등 주로 실내공기정화를 위하여 NOx 제거를 위한 선 대 평판형 플라즈마 반응기에 자석의 개수에 의한 자계세기 및 자속밀도 시뮬레이션과 도출된 시뮬레이션 결과를 바탕으로 제작된 반응기에 자석을 부가한 NOx 제거에 대한 실험을 하였다. 그 결과 자석을 부가한 경우가 NOx 제거효과에 있어 효율이 좋음을 알 수 있었다.

• Clean Technology
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• v.14 no.2
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• pp.144-151
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• 2008

Life cycle assessment was carried out to evaluate the environmental values of dimethylas a diesel alternative fuel with the assumption of dimethyl ether production from natural gas via synthesis gas. The whole life cycles from raw material acquisitions to the final usages of diesel and dimethyl ether were involved in the assessment. Inventory analysis showed that the most significant environmental impacts came from resource depletions and air emissions. Impact assessment revealed that dimethyl ether was environmentally better in the aspect of human health and ecosystem quality but worse in resource depletions compared with diesel fuel. Suggestions for environmental improvement of dimethyl ether as a diesel alternative fuel were prepared based on the assessment results.

• JOURNAL OF ELECTRICAL WORLD
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• s.264
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• pp.70-78
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• 1998

석유 등의 화석연료가 연소되면서 발생하는 이산화탄소를 주체로 하는 ''온실효과가스''의 배출량이 점점 더 증가해 감에 따라 지구온난화가 국제적으로도 커다란 환경문제가 되고 있다. 이산화탄소의 배출을 억제하기 위한 구체적인 시책은 바로 자에너지(에너지 절약/ 이용합리화)의 수행이다. 이번에 자에너지를 주목적으로, ISO14001의 환경매니지먼트 모델을 전체적으로 지원하는 공장에너지관리시스템과 조명$\cdot$빌딩분야에서 환경매니지먼트 모델을 지원하는 조명제어시스템 및 빌딩 설비 감시시스템을 구축하였다. 신규개발한 Controller의 소프트웨어는 24시간 가동가능한 OS(Operating System)에 제어미들웨어를 탑재하여 Object설계방법으로 제작된 기능별 어플리케이션 소프트웨어를 각 시스템별로 조합한다. 하드웨어는 퍼스컴과 동일한 DOS/V머신 구성으로 하여 시스템의 주체가 되는 부송부의 하드웨어를 개발하였다. 구축한 각 시스템의 내용은 다음과 같다. (1)공장에너지관리시스템 수집한 에너지사용량 데이터를 관리$\cdot$분석용으로 가공하는 생에너지 지원용 어플리케이션 소프트웨어를 탑재하고있어 환경매니지먼트 시스템(ISO14001)을 실행하는 데에도 유용하다. (2)조명제어시스템 지금까지 단독기기였던 조도일정제어의 조광컨트롤러에 B/NET 전송기능을 탑재하여 스케줄 및 디맨드 감시에 의한 조광제어를 시행하여 한층 더 생에너지를 실현한다. (3)빌딩설비 감시시스템 빌딩의 에너지관리, 조명$\cdot$공조제어에 의한 생에너지화, 보전업무의 효율화$\cdot$생력화를 실현한다.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.1
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• pp.9-16
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• 2005

Jet vane is an useful component which is installed at the end of a nozzle for the purpose of the posture control and the secure controlling stability during the initial launching of a rocket. During several seconds from its initial launching moment, the JV driving part is heated due to the direct contact of the vane with the combusted gas and the vane is ablated mechanically or chemically. In this study, as the fundamental study for the thermal analysis of jet vane, the heat transfer into a jet vane which is located in the uniform supersonic flow field is calculated. For this, boundary layer integral method and finite difference method are used simultaneously. Based on the thermal boundary conditions derived from the analysis, the transient heat conduction in the vane is also calculated.

• Journal of Hydrogen and New Energy
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• v.23 no.3
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• pp.264-273
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• 2012

In this paper, two types of integrated gasification combined cycle (IGCC) plants using either an air separation unit (ASU) or an ion transport membrane (ITM), which provide the oxygen required in the gasification process, were simulated and their thermodynamic performance was compared. Also, the influence of adopting a pre-combustion $CO_2$ capture in the downstream of the gasification process on the performance of the two systems was examined. The system using the ITM exhibits greater net power output than the system using the ASU. However, its net plant efficiency is slightly lower because of the additional fuel consumption required to operate the ITM at an appropriate operating temperature. This efficiency comparison is based on the assumption of a moderately high purity (95%) of the oxygen generated from the ASU. However, if the oxygen purity of the ASU is to be comparable to that of the ITM, which is over 99%, the ASU based IGCC system would exhibit a lower net efficiency than the ITM based system.