• 한국수소및신에너지학회논문집
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• 제13권3호
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• pp.233-241
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• 2002

To achieve hydrogen power system with high performance and stable operation, the COVimep of hydrogen fueled engine with direct injection was evaluated with the change of engine speed, injection timing, air-fuel equivalence ratio and spark timing. And the cause of cycle variation was analyzed by using coefficient of variation in combustion period defined in this study. the results showed that the cycle variation of hydrogen fueled engine is mainly dependent on the early combustion period.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.259-266
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• 1998

In the SI engine, the improvement of combustion stability is important not only for the fuel consumption rate but also for the emission control at idling of engine. Thus the engine speed fluctuation at idle operation mainly comes from cyclic variation of combustion in the SI engine. In this syudy, the improvement of combustion stability for the SI engine at idle condition by the cooling water temperature, duty ratio of ISC, spark ignition timing as well as the reducement of the harmful exhaust gas emission was discussed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.975-980
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• 1992

The purpose of this paper is to perform the engine driving well with controling the IAC(Idle Air Control) valve which controls the demand-air when the abrput increasing or decrasing and the idling, the fuel by controlling the injector, and the spark timing. This plant is the complex system because this should be controlled each other and each one affects other. We have controlled this system effectively by using Personal Computer in order to reduce the exhaust gas and improve the engine performance.

• 오토저널
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• 제9권5호
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• pp.66-76
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• 1987

The control technique for an electronic engine is studied. For this study an IBM-PC and a throttle body fuel injection system are selected. The computer controls fuel injection, spark timing, exhaust gas recirculation and idle speed. Fuel injection is adjusted either by a feed back signal of a zirconia $O_{2}$ sensor or programmed logic for starting, deceleration, warm ing up and idle modes. When a 3-way catalytic converter is used with the electronic engine control system, CO, THC, and NOx were reduced more than 90% simultaneously.

• 한국수소및신에너지학회논문집
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• 제26권1호
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• pp.28-34
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• 2015

HCCI (Homogeneous Charged Compression Ignition) hydrogen engine has relatively narrower operation range caused by backfire occurrence due to the rapid pressure rising by using higher compression ratio and significant reaction velocity. In this study, to grasp of backfire process and characteristic in the HCCI research hydrogen engine, in-cylinder pressure, intake pressure and backfire limit range are analyzed with compression ratio and intake valve open timing, experimentally. As the result, it is observed that knock is occurred just before backfire occurrence in HCCI hydrogen engine but not spark igntion type, this phenomenon is always the same for the above variables. Also backfire limit range are expanded up to 50% for the more retarding intake valve open timing in this operating conditions.

• 동력기계공학회지
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• 제9권1호
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• pp.14-22
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• 2005

This work deals with a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel is injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector is water-cooled by a specially designed coolant passage. Investigated are the engine performance and emission characteristics under the wide range of operating conditions such as 40 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, $150\;to\;180^{\circ}C$ in the inlet-air temperature, and $80^{\circ}$ BTDC to $20^{\circ}$ ATDC in the injection timing. A controlled auto-ignition gasoline engine can be achieved that the ultra lean-burn with self-ignition of gasoline fuel by heating inlet air. It can be achieved that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide had been significantly reduced by CAI combustion compared with conventional spark ignition engine.

• 한국자동차공학회논문집
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• 제13권1호
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• pp.9-18
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• 2005

The objective of this study is to analyse the spray characteristics according to the injection duration under the ambient pressure condition, and the injection timing in the visualization engine. In order to investigate the spray behavior, we obtained the spray velocity using the PIV method that has been an useful optical diagnostics technology, and calculated the vorticity from spray velocity component. These results elucidated the relationship between vorticity and entropy which play an important role in the diffusion process for the early injection case and the stratification process for the late injection case. In addition, we quantified the homogeneous diffusion rate of spray using the entropy analysis based on the Boltzmann's statistical thermodynamics. Using these method, it was found that the concentration of spray droplets caused by the increase of injection duration is more effective than the increase of momentum dissipation. We also found that the homogeneous diffusion rate increased as the injection timing moved to the early intake stroke process and BTDC $50^{\circ}$ was the most efficient injection timing for the stratified mixture formation during the compression stroke.

• 한국자동차공학회논문집
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• 제19권3호
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• pp.65-72
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• 2011

In this study, the numbers, sizes of particles from a single cylinder direct injection spark-ignition (DISI) engine fuelled with gasoline and LPG are examined over a wide range of engine operating conditions. Tests are conducted with various engine loads (2~10bar of IMEP) and fuel injection pressures (60, 90, and 120 bar) at the engine speed of 1,500 rpm. Particles are sampled directly from the exhaust pipe using rotating disk thermodiluter. The size distributions are measured using a scanning mobility particle sizer (SMPS) and the particle number concentrations are measured using a condensation particle counter (CPC). The results show that maximum brake torque (MBT) timing for LPG fuel is less sensitive to engine load and its combustion stability is also better than that for gasoline fuel. The total particle number concentration for LPG was lower by a factor of 100 compared to the results of gasoline emission due to the good vaporization characteristic of LPG. Test result presents that LPG for direct injection spark ignition engine help the particle emission level to reduce.

• 스마트미디어저널
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• 제6권4호
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• pp.58-64
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• 2017

현대 사회는 급속한 세계인구의 증가, 농촌 인구의 고령화, 산업화로 인한 농작물 재배 지역의 감소, 농촌 지역의 수익 구조의 불량 등으로 농부들의 탈농촌화 등으로 먹거리 문제 해결이 중요한 화두로 떠오르고 있다. 최근 농촌의 수익을 증대시키기 위해서 스마트 팜(Smart Farm) 분야의 연구가 활발하게 이루어지고 있다. 기존의 스마트 팜 연구는 주로 온실의 농작물의 재배 환경을 모니터링 하여 온실의 조도, 습도, 토양 등이 불량해지면 재배 환경인자를 제어하는 시스템을 자동으로 가동시켜 농작물의 재배 환경을 최적의 상태로 유지하는 데 중점을 두어 연구되고 있다. 즉, 실내에서 재배하는 농작물에 중점을 두어 연구가 이루어지고 있으며 실외에서 재배되는 농작물의 재배환경에 적용되는 연구는 많이 이루어지지 않았다. 본 논문에서는 과수원에서 자라는 과수의 수확 시기를 정확하게 예측하여 최상의 품질로 과일이 수확되게 지원하고 수확이 불량한 지역을 빅데이터 분석을 통해 모니터링하여 불량 지역의 수확성을 향상시키기 위해서 집중 관리할 수 있은 기능을 제공하는 아키텍처를 제안한다. 수확에 관련된 인자는 과일 색상 정보와 과일 무게 정보를 사용하며 실시간으로 수집되는 수확 상관인자 데이터를 Apache Spark 엔진을 이용하여 분석하도록 제안한다. Apache Spark 엔진은 대용량 배치성 데이터 분석 뿐만 아니라 실시간 데이터 분석에서도 우수한 성능을 보인다. 서비스를 수신하는 사용자 디바이스는 PC User 와 Smart Phone User를 지원한다. 센싱 데이터 수신 장치는 센싱되는 데이터를 수신한 후 서버로 전송하는 단순한 처리만 필요하므로 Arduino를 적용하였다. 과일의 수확시기를 조절하여 좋은 품질의 과일을 생산하려면 수확이 불량한 지역을 판단하여 불량지역을 집중 관리해야 한다. 본 논문에서는 빅 데이터 분석 기법을 이용해서 과일 수확의 불량지역을 판단하는 아키텍처 모델을 제안한다.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.86-92
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• 2003

To analyze the characteristics of ozone formation, measurements of the concentrations of individual exhaust hydrocarbon species have been made under various engine operating parameters in a 2-liter 4-cylinder engine for natural gas and LPG. Tests were performed at constant engine speed, 1800 rpm for two compression ratios of 8.6 and 10.6, with various operating parameters, such as excess air ratio of 1.0~1.6, bmep of 250~800 na and spark timing of BTDC 10~$55^{\circ}$. It was found that the natural gas gave the less ozone formation than LPG in various operating conditions. This was accomplished by reducing the emissions of propylene($C_3H_6$), which has relatively high maximum incremental reactivity factor, and propane($C_3H_8$) that originally has large portion of LPG. In addition, the natural gas show lower values in the specific reactivity and brake specific reactivity. Higher compression ratio of the test engine showed higher non methane HC emissions. However, specific reactivity value decreased since fuel species of HC emissions increase. brake specific reactivity showed almost same values under high bmep, over 500kPa for both fuels. This means that the increase of non methane HC emissions and the decrease of specific reactivity with higher bmep affect each other simultaneously. With advanced spark timing, brake specific reactivity values of LPG were increased while those of natural gas showed almost constant values.