• Journal of the Korean Institute of Gas
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• v.20 no.3
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• pp.30-37
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• 2016

Electrical apparatuses for use in the presence of flammable gas atmospheres have to be specially designed to prevent them from igniting the explosive gas. Flameproof design implies that electrical components producing electrical sparks are contained in enclosures and withstand the maximum pressure of internal gas or vapours. In addition, any gaps in the enclosure wall have to designed in such a way that they will not transmit a gas explosion inside the enclosure to an explosive gas or vapours atmosphere outside it. In this study, we explained some of the most important physical mechanism of MESG(Maximum Experimental Safe Gap) that the jet of combustion products ejected through the flame gap to the external surroundings do not have an energy and temperature large enough to initiate an ignition of external gas or vapours. We measured the MESG and maximum explosion pressure of ternary gas mixtures(propane-acetylene-air) by the test method and procedure of IEC 60079-20-1:2010. As a result, the composition of propane gas that has lower explosive power than acetylene gas in the ternary gas mixtures makes greater effects on MESG and explosion pressure.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.8-17
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• 2010

This paper proposes a novel LCD CCFL-backlight electronic ballast using the phase-shift full-bridge inverter. The proposed electronic ballast reduces the ignition voltage and eliminates current spikes using the new digital dimming control applied with soft-starting. Thus the electronic ballast improves ignition behavior of the CCFL and hence increases the CCFL's life span. For this, this paper analyzes the full-bridge inverter topology of the proposed electronic ballast and explains the new digital dimming control algorithm applied to the ballast, briefly. And this paper shows a design example of the prototype circuit and explains an implementation method of the digital dimming control which is implemented on a single-chip microcontroller with software. This was implemented as actual prototype electronic ballast, and its experimental results showed that the proposed electronic ballast operates correctly. The ignition voltage of the prototype in the digital dimming operation was reduced about 30[%] compared with the conventional electronic ballast and there were not any current spikes.

• Journal of IKEEE
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• v.18 no.2
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• pp.179-184
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• 2014

In this paper, we have developed a data monitoring system for activation analysis based on fuel heater of diesel cars. The light oil of diesel engine below a constant temperature be changed to the waxing materials of a semisolid status like a paraffin, and then it may not start. In order to evaluate an engine activation performance, we suggest an engine start time with an change between an extremely low temperature and high temperature, a delay time goes with heater resistor and current and pressure. So, we have developed sensor module system that can obtain the operational status data between fuel line and fuel heater, and evaluate the performance of fuel heater through monitoring of a temperature and pressure. Finally, we can gather the temperature and pressure data of this system with mobile terminal, remotely and propose an utility of this system that can find problems of fuel heater through measured data.

• Journal of the korean Society of Automotive Engineers
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• v.6 no.3
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• pp.36-44
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• 1984

The prediction of the emission concentrations in 4-cycle 4-cylinder spark ignition engine is made by considering the model with the extended Zedovich mechanism. The predicted values for nitric oxide, carbon dioxide and carbon monoxide agree with the experimentally measured ones.

• Fire Science and Engineering
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• v.30 no.5
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• pp.1-8
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• 2016

Safety management in hazardous areas with potentially explosive gas atmospheres (here in after referred to as hazardous areas) in large scale facilities dealing with combustible or flammable materials at home and abroad is very important (significant) for the coexistence of the company and local society based on business continuity management (BCM) and reliance. For the safety management in hazardous areas, two systems are mainly used: (1) the control system for the prevention of combustible or flammable substances and (2) the explosion proof system for the elimination of ignition sources when flammable gases are leaked to inhibit the transition to fire or explosion accidents. While technology and regulations on explosion proof facilities or devices for electrical ignition sources are well developed and defined, those for thermal ignition sources need to be more developed and established. In this study, the internal combustion engine in hazardous areas was investigated to determine the risk of ignition. For this purpose, document searches were conducted on the relevant international standards and accidents cases and risk analysis reports. In addition, this study assessed the application cases of the diesel engine's safety equipment, such as spark arresters regarding the site of process safety management (PSM) system in central Korea. To practically apply these results to the hydrocarbon industry, the safety management method for explosion prevention in hazardous areas was provided by risk identification for ignition sources of internal combustion engines, such as diesel engines.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.9
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• pp.1736-1743
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• 1992

The combustion in the cylinder of spark ignition engine is completed after the delayed time that the liquid film fuel is vapourized as flowing into the combustion chamber. It is necessary to enhance the homogeneity of mixture and the combustion phenomenon in order to improve the heat efficiency and the emission characteristics of spark ignition engine. The main purpose of this paper is to manufacture a combustion analyzing system and examine closely the influence of non-uniformity due to the liquid film fuel flowing in the intake manifold on the combustion characteristics by using a 4 stroke multi- cylinder spark ignition engine. Moreover, with each cylinder, the interpretation of combustion characteristics by indicator diagram and the concentration of exhaust gas were investigated.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.4
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• pp.75-82
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• 1990

To study on the behavior of the early stage of the spark kernel at constant pressure condition, the expressions of the thermal properties such as compressibility factor, thermal conductivity, and electrical conductivity of the high temperature air were newly suggested. The newly suggested simple expressions of the thermal properties of the high temperature air showed good results. Under the assumption of constant pressure, one dimensional numerical analysis was executed by varying surrounding conditions and discharging current of electrical spark. Numerical results show tat high surrounding pressure suppresses the growth of the spark kernel but supplies much electrical energy into the air, on the other hand high surrounding temperature increases the growth of the spark kernel but supplies less electrical energy. Also the result shows that , in case of direct current discharge, deposited electrical energy is able to be expressed in linear function of time approximately.

• Journal of the Korean Institute of Gas
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• v.8 no.1 s.22
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• pp.18-24
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• 2004

This study issues the component's ratings when low powered do intrinsic safety instrumentations using in flammable atmospheres. Test of reverse bias of zener diode characteristics and ignition characteristics test for power source consist of zener diode and resistor have done using IEC spark test apparatus. With this test, the ratings for zener diode and resistor are calculated and the design method of intrinsically safe power supply system is reported.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1203-1205
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• 1987

가솔린 엔진용 전자 제어 에뮬레이션 시스템은 엔진의 운전 상태를 알려 주는 각종 센서로 감지한 정보를 A/D변환기를 통해 마이크로프로세서에 입력시키고, 이 정보를 이용하여 운전 상태를 분석한 후 엔진이 푤요로 하는 연료량, 점화시기, 배기가스의 재순환량, 공회전수 등을 전자적으로 제어하여 엔진의 최적제어를 실현시킴으로서 연료소비율 및 배기가스 중 공해물질 함량을 감소시키기 위한 장치이다.

• Proceedings of the KIEE Conference
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• 2000.11d
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• pp.624-628
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• 2000

이 논문에서는 이산형 상태 공간 모델에서의 새로운 FIR 필터를 제안한다. 선형성, 무진동성, FIR 구조, 초기 조건과의 무관성등을 디자인 과정에서 고려해서 성능 지표를 최소화 하는 필터를 구한다. 성능지표로는 구간에서 외란 에너지와 현재 추정 에러의 최대 이득으로 생각하며, 이 지표는 일반적인 성능지표와는 다르다. 제안된 필터는 배치 형태로 먼저 구하고, 점화식 형태로 바꿀 수 있음을 보인다. 제안한 필터는 확률론적 시스템의 이동 구간 무편향 FIR 필터(RHUFF)와 유사함을 보인다.