• Journal of Energy Engineering
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• v.18 no.3
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• pp.163-168
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• 2009

This paper describes the homogeneous charge compression ignition (HCCI) engine for a new concept. HCCI engines are being considered as a future alternative for diesel and gasoline engines. HCCI engines have the potential for high indicated thermal efficiency under part load and very low NOx emissions. The objective of this paper is to clear the effects of exhaust gas recirculation (EGR) rate on the HCCI. For this purpose, a 4-cylinder, compression ignition engine was converted into a HCCI engine This work has been run with propane and butane fuels at a constant speed.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.586-587
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• 2012

자동차 산업에 있어서 반도체 기술발전과 더불어 차량 내 기능들이 효율성, 경제성 및 친환경적인 관심을 고려하여 기계식 방식에서 전력전자식 방식으로 대체되고 있는 실정이다. 엔진의 연비를 향상시키기 위해서는 엔진의 연소효율을 개선하거나, 엔진에서 발생되는 손실을 줄이는 것이 필요한데, VVA(Variable Valve Actuation, 가변 밸브 작동) 기술은 엔진 흡기 유동 강화, 펌핑 손실 저감, 기계적 마찰 손실 저감등을 통해 엔진의 연비를 향상시킬 수 있다. 또한 VVA 엔진을 장착한 차량은 차량의 발진 응답성이 향상되고, 배기가스 배출량을 줄일 수 있어 친환경 저연비 차량을 실현하는데 핵심 차량부품기술이다. 최근까지 차량의 전동기 구동의 경우 DC모터 방식이 많이 적용되어 왔으나 DC모터의 내구성 및 효율 등의 이유로 BLDC모터로 바뀌고 있는 추세이다. 본 논문에서는 이와 같은 VVA 기구의 적용을 위하여 BLDC모터 제어기를 개발하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.1-7
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• 2008

Recent trends of development in small size gasoline engines are both to have higher compression ratio for the purpose of improved fuel consumption and to advance spark timing up to DBL in a low to mid engine speed region for a good acceleration performance of vehicles. However, there occurs the deviation of corrected engine torque results during engine performance test on dynamometer because test conditions influence the onset of knock. Therefore, this research shows the test deviation of corrected engine torque decreases when knock correction rate is used.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1037-1038
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• 2007

프리피스톤 기관은 크랭크가 없는 엔진을 동력원으로 리니어 발전기를 구동시켜 전기에너지를 생성하는 시스템으로 기존 왕복 구동식 기관에 비해 기계적 손실이 작고, 팽창 에너지를 최대한 활용할 수 있는 고효율 기관으로 평가되고 있다. 또한 프리피스톤 기관은 가솔린, 디젤, 수소, 천연가스와 같은 청정 연료를 사용할 수 있기 때문에, 최근 에너지 수급 문제 및 대체 에너지원으로 활용할 수 있다는 장점을 가지고 있다. 프리피스톤 기관에 적용되는 리니어 발전기의 경우 기존 회전형 발전기보다 효율은 다소 떨어지는 단점은 있으나, 동력 변환을 하지 않는 리니어 엔진에 적용할 경우에는 효율적 이득을 볼 수 있다. 본 논문에서는 리니어 발전기의 성능 측정을 위한 시험 장치를 구성하고, 프리피스톤용 기관에 적용되는 평판형 및 원통형 타입의 리니어 발전기의 손실 및 효율 특성을 비교하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.2
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• pp.121-127
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• 2011

NOx (Nitrogen Oxide) reduction system periodically needs a rich or stoichiometric operating condition to reduce NOx. A new method that optimizes the control of external HC injection into a diesel exhaust pipe for HC-type LNT (Lean NOx Trap) catalyst system has been developed. In this paper, these catalysts are called HC-LNT catalysts. The concentration and amount of HC can be controlled by controlling the external injection. In this study, we investigated the relationship between the spray behavior of hydrocarbons injected into the transparent exhaust pipe and NOx reduction characteristics. From the results of this experiment, we obtained useful information about the optimum injection and position of HC injector to the exhaust pipe. Further, we obtained useful information about the optimal injection condition for an HC-LNT catalyst system with a gasoline PFI (port fuel injection) typeinjector.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.7-13
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• 2003

The purpose of this study is to investigate the effect of the in-cylinder flows and different injection timings on fuel behavior in the cylinder of a GDI engine. Three different flows types induced by using masked port, unmasked port, and port deactivation were tumble, swirl&tumble, and high swirl respectively. LIEF technique was applied to investigate the mixture formation and fuel distribution at ignition time in the transparent engine with optical access through the piston top and upper part of cylinder liner. Injection timings of 180,90, and 60 degrees before TDC were examined. It was found that tumble flow was more effective on the homogeneous mixture formation than other flow and swirl flow transported more fuel vapor to the exhaust side at early injection mode, and swirl and swirl & tumble flow made fuel vapor concentrate around the cylinder center at late injection mode.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.279-282
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• 2009

Motohawk ECU(Engine Control Unit)에 의한 가솔린기관의 연료분사제어 알고리즘 연구를 통하여 연비를 절감할 수 있는 방안을 연구한다. 실제 차량엔진 ECU는 캘리브레이션 이외의 제어 알고리즘을 변경하여 구현하기가 쉽지 않으므로 상기의 프로토타입 ECU를 활용하여 연료분사제어 로직을 변경해가면서 연료분사와 관련된 여러가지 파라메터의 연구가 가능하다. 또한 프로그래밍은 Matlab과 Simulink로 구현할 수 있어서 최적연비를 얻기 위한 로직의 구현을 실시간으로 할 수 있으며 차량의 특성상 프로그램의 임베딩이 가능하여야 하므로 이러한 목적에 프로토타입 ECU에 의한 로직개발은 많은 장점이 있다. 이러한 ECU를 활용하여 여러 가지 제어 변수에 의한 최적화된 연료분사 로직의 설계 및 미치는 영향을 평가한다.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.65-71
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• 1999

Recently new engine system is being required to cope with intensive emission restriction . For this reason, GDI(Gasoline direct injection) engine system which can satisfy both as good fuel economy as diesel engine and the performance to surpass PFI gasoline engine is being development . Since fuel injection system plays a significant role in GDI engine performance, the investigation of the spray characteristics injected from GDI injector above all is indispensable for GDI system development. In this study , spray developing shape was visualized using laser sheet with Nd : YAG laser and atomization characteristics was analyzed by measuring velocities and droplet size with PDA. Utilizing these results , the basic design factor of GDI injector can be offered.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.127-133
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• 2008

Since the 1960's, exhaust gas recirculation(EGR) has been used effectively in spark ignition(SI) engines to control the exhaust emissions of the oxides of nitrogen(NOx). The most important requirements for the application of EGR systems to conventional SI engines are controllable flow rate and good dynamic response. In order to evaluate the characteristics of the electronic EGR valve, a test bench which is consisted of blower, heater, air flow meter and driving unit for electronic EGR valve was set up to simulate engine operating conditions. During the tests, the valve actuation parameters were controlled and the valve lifts and flow rates were measured to infer the characteristics of EGR valve. The results confirmed the capabilities of mathematical analysis and it seems that the correction for the valve lift and potentiometer output is necessary to achieve precise control of EGR rates.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.353-358
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• 2000

To achieve the requirement for high fuel economy and low emissions, the research for GDI engines is recently very brisk in the whole world. This study was performed to measure distribution of average particle size in non-evaporating spray. The 2-D fluorescence/scattering images of fuel spray were captured simultaneously by visualization system composed of a laser sheet, a doubling prism, optical filters, and an ICCD camera. Using the ratio of the two light intensities, particle size distribution was obtained. The SMD measured by fluorescence/scattering technique was compared with it obtained by PDA. The experimental results show that the spray structure of GDI injector and temporal SMD distribution.