• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.395-400
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• 2017

The paper discussed the air-to-fuel ratio control of automotive fuel-injection systems using the cerebellar model articulation controller(CMAC) neural network. Because of the internal combustion engines and fuel-injection's dynamics is extremely nonlinear, it leads to the discontinuous of the fuel-injection and the traditional method of control based on table look up has the question of control accuracy low. The advantages about CMAC neural network are distributed storage information, parallel processing information, self-organizing and self-educated function. The unique structure of CMAC neural network and the processing method lets it have extensive application. In addition, by analyzing the output characteristics of oxygen sensor, calculating the rate of fuel-injection to maintain the air-to-fuel ratio. The CMAC may easily compensate for time delay. Experimental results proved that the way is more good than traditional for petrol control and the CMAC fuel-injection controller can keep ideal mixing ratio (A/F) for engine at any working conditions. The performance of power and economy is evidently improved.

• Annual Conference of KIPS
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• 2006.11a
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• pp.291-294
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• 2006

본 연구는 화재로부터 인명과 재산을 보호하기 위한 자동 소화 시스템으로서 마이컴을 사용하여 고신뢰성, 고정밀도, DIGITAL화를 추구하는 시스템을 개발 하였다. 기존의 소화 방제 시스템들은 스프링클러를 사용하여 물로 화재를 진압하고 있으며 이러한 시스템은 비용이 많이 들고 대량의 물을 사용하고 있기 때문에 수손피해($80{\sim}120{\ell}/min$)가 있고 대용량 펌프 및 $47,000{\ell}$의 저장시설이 필요하다. 이러한 문제점을 해결하기 위하여 본 시스템은 이산화탄소($CO_2$ 가스나 하론1301 가스 또는 질소 가스를 분사하여 대기 중의 산소를 희석시키거나 질소의 양을 증가시키는 방법으로 화재를 진압하는 시스템을 개발 하였다. 개발된 시스템은 고가의 장비 즉, 전산실, 통신기기실, 전기실, 발전기실, 케이블실, 제어실, 필름 보관실 등에 사용되어 장비를 보호하고 인명의 피해를 최소화하는데 사용될 것 있다.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.835-838
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• 2009

본 논문은 환경공해의 주범인 자동차의 매연을 감소할 수 있는 방법에 대한 연구이다. 자동차 매연의 주요원인은 연료의 불완전 연소와 연료 자체의 특성때문이다. 따라서 본 논문에서는 가솔린/경유 차량을 CNG/LPG 차량으로 대체하고 CNG/LPG연료의 특성을 감안하여 연료의 공급과 분사량, 분사시간을 차량 ECU에서 보내지는 신호를 기본데이터로 차량의 가속과 감속 아이들 상태에서 차량을 적응적으로 최적화 할 수 있게 실시간으로 보정데이터를 계산한다. 본 논문의 결과로 기존의 구조변경차량의 출력에서 20%이상, 배기가스 에서 10% 이상의 향상되었다.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.34-39
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• 2015

Recently, most of the energy consumed in vehicle is derived from fossil fuels. For this reason, the demand for clean, renewable and affordable alternative energy is forcing the automotive industry to look beyond the conventional fossil fuels. Natural gas represents today a promising alternative to conventional fuels for vehicles propulsion, because it is characterized by a relatively low cost, better geopolitical distribution than oil, lower environmental impact, higher octane number and a higher self ignition temperature. Above all, CNG is an environmentally clean alternative to the existing spark ignition engines with the advantages of minimum change. In this study was installed bi-fuel system that a conventional 2 liters gasoline engine was modified to run on natural gas by a gas injection system. Experiments were mainly carried on the optimization of an ECU control strategy affecting the emission characteristics of CNG/Gasoline bi-fule vehicle. The test results shown that CO2 emission in bi-fuel mode was reduced 16% compared to gasoline fuel in the NEDC mode. Also the amount of CO and HC emissions in bi-fuel and gasoline modes were found to equality. But Compared to gasoline, the bi-fuel mode resulted in higher NOx emissions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.10
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• pp.1001-1009
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• 2012

In this study, the cooling characteristics of combustion gas were investigated by injecting liquid nitrogen ($LN_2$) into a liquid rocket combustion chamber, which uses liquid oxygen (Lox) and kerosene as propellants. $LN_2$ injectors and an extended chamber for mixing were installed at the end of the ordinary LRE combustion chamber, and a nozzle was installed after the chamber for mixing. First, an ignition test of the liquid rocket engine was conducted to verify the stable combustion process. Next, a hot firing test was performed step-by-step for safety. Finally, the test was performed for 20 s. The results showed that the combustion gas of the LRE could be successfully cooled by using $LN_2$.

• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.48-53
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• 2012

The purpose of this paper studies the failure cases including with system of liquefied phase injection in liquified petroleum gas vehicle. The first case, resulting with inspection the injector of LPG, it occasionally certified the injection damage phenomenon that the fuel efficiency(km/l) was decreased to 5% by carbon deposit with injector hole when the driver operates the vehicle. The second case, it certified the interference phenomenon of air flow with carbon deposit in ISA system control for idle speed of engine and throttle body suppling air into engine. As a result, the fuel efficiency was decreased 7%. The third case, the outer air during intake stroke was intermittently flowed in this gasket gap because of weaken adhesion power phenomenon for cylinder block by intake manifold gasket tearing. Consequentially, it certified the decrease for fuel efficiency to 3% by risen the amount of fuel injection as the air inflow quantity. These failure examples reduced the power performance of engine and the fuel efficiency of vehicle. It have to minimize of failure phenomenon preparing through quality management.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.816-819
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• 2007

국내에서 IGCC 플랜트의 복합발전시스템의 평가는 여러 분야별로 진행되어 왔다. 크게 살펴보면 다음과 같다. 첫 번째는 가스터빈 쪽의 기술이다. 즉, 기존 천연가스를 이용하는 가스터빈을 어떻게 하면 석탄가스를 사용하는 IGCC 플랜트에 적합하게 맞출 것인가 하는 문제이다. 두 번째는 효율을 어떻게 하면 높일 수 있는가의 문제로서 석탄의 종류, 가스화 방법을 효율적으로 선택, HRSG(heat recovery steam generator)를 효율적으로 설계, 그리고 정제공정에서의 에너지 소비를 줄이는 분야였다. 세 번째는 어떻게 하면 오염을 줄일까의 문제로서 질소나 스팀 분사를 연계하여 NOx를 감소시키고 정제 공정에 사용되는 촉매를 개발한다던지 공정을 발달시키는 분야였다. 이 외에도 여러 종류의 연구가 이 분야에서 있었으나 주로 설계 분야의 연구가 주되였다. 이것은 발전소의 건설을 위한 초기 단계로서 당연한 결과일 수 있다. 그러나, 지금 IGCC 플랜트가 건설되는 과정에 있으므로 우리나라 전력계통 연계와의 문제도 생각해보아야 한다고 생각한다. 따라서 이번 연구에서는 IGCC 플랜트 운영의 불확실성이 약간이라도 존재하기에 이 플랜트가 기저발전 보다는 첨두발전 쪽이나 태양열/광발전, 풍력발전 등 다른 신재생에너지 자원처럼 독립된 전력 시스템으로 운영될 것이라 생각하고 이렇게 운영될 때는 발전소의 부하률의 변화가 심할 수 있다는 가정하에 플랜트의 부하률에 따른 석탄의 합성가스, 연료가스 전환량 및 전환효율 및 발전량 및 발전효율을 전산모사를 통해 예측해보았다.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.9-16
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• 2019

The experiment on the liquid jet in crossflow in supersonic BFS (backward-facing step) flow was conducted to investigate the mixing characteristics. The working fluids are nitrogen and water. The shadow graph technique was used to visualize the flow field. Images captured by the high-speed camera were applied to analyze the flow phenomena. The liquid jet was injected at the re-circulation zone created by the supersonic jet flow. Experimental conditions are defined based on the pressure of the nitrogen gas chamber and pressurized liquid tank. In respective cases, the penetration depth of liquid jet and location of the Mach disc were observed to be proportional to the momentum ratio of gas and liquid jets.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.53-59
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• 2011

The using of diesel engine will be increased in the world for fuel economy. But diesel engine emits harmful emissions such as much NOx, smoke etc. In this study, experiments were performed to investigate the spray characteristics of diesel spray in a common-rail system according to fuel temperature, injection pressure, injection period and fuel viscosity etc. using a high speed video camera. Diesel oil has different spray patten due to injection pressure and injection period in a common-rail system. A Filter pressure was influenced by fuel temperature which was turned to fuel viscosity related to a fluid flowing. The effect of the bio-diesel fuel mixing ratio on the spray and atomization characteristics was also investigated at various experimental conditions. It shows that the droplet atomization characteristics of bio-diesel fuel showed deteriorated results as the mixing ratio of biodiesel increased because of the high viscosity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.8
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• pp.448-455
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• 2009

A performance analysis of the regenerative gas turbine system with afterfogging is carried out. Because of the high temperature at the outlet of air compressor, afterfogging has a potential of improved recuperation of exhaust heat than inlet fogging. Thermodynamic analysis model of the gas turbine system is developed by using an ideal gas assumption. Using the model, the effects of pressure ratio, water injection ratio, and ambient temperature are investigated parametrically on thermal efficiency and specific power of the cycle. The dependency of pressure ratio giving peak thermal efficiency is also investigated. The results of numerical computation for the typical cases show that the regenerative gas turbine system with afterfogging can make a notable enhancement of thermal efficiency and specific power. In addition, the peak thermal efficiency is shown to decrease almost linearly with ambient temperature.