• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2423-2430
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• 1994

Several factors of the efficient combustion process are shape of combustion chamber, position of spark plug, turbulence flow and so on. the shape of combustion chamber and position of spark plug are constrained to geometrically, and then it could not make a change the shape easily. But the turlence flow in combustion chamber have a great influence on combustion phenomena, and which is much easier to control relatively. And since characteristics of turbulence flow would be very important to the stability of combustion and performances, This study is also essential to future engine-low emission and lean burn engine. This paper shows that the visualization of the turbulence flow of single cylinder engine by using 2way, $45^{\circ}$ inclined and 2 channel hot wire probe through the park plug hole. We also study the characteristics of turbulence flow by means of ensemble averaged mean velocity, turvulence intensity and integral length scale.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_2
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• pp.73-77
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• 2001

The disposal of sewage sludge using landfills and ocean dumping is no longer a viable option due to land scarcity and increasingly stringent environmental control regulations. As such, various efforts have been made to develop new sewage sludge recycling technologies. This work investigates the fundamental physical and chemical characteristics of rural type sewage sludge from Chungnam province in South Korea. The average moisture content, ignition loss, elementary analysis, and average heating value of the sewage sludge samples were examined. The average moisture content of the dewatered sludge was about 80%, while the organic matter was about 50% of the total solid sludge weight. The average heating value of a sewage sludge and petroleum coke waste mixture(1:1 weight ratio) was about 5,000 ㎉/kg, thereby indicating a high potential for energy recycling.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.211-219
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• 1996

In a small high-speed D. I. diesel engine, the injected fuel spray into the atmosphere of the high temperature is burnt by go through the process of break up, atomization, evaporation and process of ignition. These process are important to decide the emission control and the rate of fuel consumption and out put of power. Especially, in the case of injected fuel spray impinging on the wall of piston cavity, the geometry of piston cavity gives great influence the ignitability of injected fuel and the flame structure. Ordinary, the combustion chamber of driving engine have unsteady turbulent flow be attendant on such as the change of temperature, velocity and pressure. So the analysis of spray behavior is difficult. In this study, the spray was impinged on the wall of 3 types of piston cavity such as Dish, Toroidal, Re-entrant type, in order to analyze the combustion process of impinging spray precisely and systematically. And hot wire probe was used for analyze non-steady flow characteristics of impinging spray, and to investigate the behavior of spray, the aspects of concentration c(t), standard deviation σ(t) and variation factor(vf) was measured with the lapse of time.

• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.63-69
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• 2013

The purposes of this study are to survey stereotypes of control-display relationships for seven principal controls in passenger cars using the paper-pencil and hardware tests, and to examine stereotype strength of the paper-pencil test through comparing the stereotypes for the controls derived by the two methods. Ninety two and 60 college-aged students participated in the paper-pencil test and the real car simulation of the hardware test, respectively. There are dominant motion-directions for all controls in the paper-pencil test, while in the hardware test, there are dominant motion-directions for six controls including head light, high beam, door window, ignition key, door key and door lock controls. The stereotypes of motion-directions for six controls obtained by the paper-pencil test were the same as or similar to those by the hardware test. It was inferred from this that the congruence of the stereotypes by the two methods might be attributed to two simple motion-direction principles of 'clockwise for increase' and 'upward for increase.' Although it is known that the hardware test would be best for obtaining accurate stereotypes between controls and displays, this study implies that if the paper-pencil test is well designed, the paper-pencil test can produce the same results as the hardware test at low cost and without consuming time.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.2
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• pp.18-25
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• 2002

In this paper, We have researched about the Electronic Ballast for 250W HPS(High Pressure Sodium) lamp. This Electronic Ballast is capable to operate the Ignition and Steady State Using the Class D LCC resonant tank, and minimizing the full-bridge inverter's Switching Stress by implementation Quasi-square ZC-ZVS Soft Switching Method. And also, We have reduced the heat of MOS-FETs and high frequency switching surge noise using the RCD damp snubber. Therefore, We are sure that the developed ballast has the properties of the stable & reliable Control and the function of minimizing the total noise of the system.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.27-37
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• 1997

Internal combustion engine is the main source of environmental pollutants and therefore better technology is required to reduce harmful elements from the exhaust gases all over the world. Especially, harmful elements from the exhaust gases are caused by incomplete combustion of mixture inside the engine cylinder and this abnormal combustion like misfire or partial burning is the direct cause of the air pollution and engine performance degradation. the object of this research is to detect abnormal combustion like misfire and to keep the engine performance in the optimal operating state. Development of a new system therefore could be applied to a real car. To realize this, the spark-plug in a conventional ignition system is used as a misfire detection sensor and breakdown voltage is analyzed. In this research, bias voltage(about 3kV) was applied to the electrodes of spark-plug and breakdown voltage signal is obtained. This breakdown voltage signal is analyzed and found that a combustion phenomena in engine cylinder has close relationship with harmonic coefficient K which was introduced in this research. Newly developed combustion diagnostic method( breakdown voltage signal analysis) from this research can be used for the combustion diagnostic and combustion control system in an real car.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.8-15
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• 2003

During cold operation, fuel injection in the intake port directly contributes to the unburned hydrocarbon formation in spark ignition engines. The relationship between injection parameters and HC emission behavior was investigated through a series of experiments. Spray behavior of port fuel injectors was characterized through a quantitative evaluation of mass concentration of liquid fuel by a patternator and PDA(Phase-Doppler. Anemometer). A 6-hole injector was found to produce finer spray than single hole injector. Using a purpose-built wall, the wetted fuel was measured, which was mostly affected by wall temperature. HC emissions were measured in a production engine varying coolant temperature$(20~80^{\circ}C)$, also with respect to the different types of injectors. In the 6-hole injector application, the engine produced less HC emission in low coolant temperature region. Though it produces much more amount of wetting fuel, it has the advantages of finer atomization quality. In high coolant temperature region, there was little effect by different types of injectors. The control schemes to reduce HC emissions during cold start could be suggested from the findings that the amount of fuel supply and HC emission could be reduced by utilizing fine spray and high intake wall temperature.

• Fire Science and Engineering
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• v.24 no.4
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• pp.92-97
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• 2010

Fire simulation by using a computational fluid dynamics model and examination of the fires at indoor shooting ranges broken out in the past were conducted, to presume causes of the fire at the indoor shooting range in Busan and suggest fire safety measures. On-site investigations and shooting tests on unburned gunpowder were also carried out. No trace of the muzzle spark and spark at the bullet trap was found in CCTV footage, and the impact of a stray bullet failed to ignite gunpowder. Cigarette was therefore presumed to be the most likely source of ignition among the potential sources. It appeared that the explosion in the shooting area was caused by violent burning of the polyurethane sound absorber and unburned gunpowder accumulated on it. The fire safety measures include prohibit of use of profile polyurethane sound absorber, removal of steel components from bullet trap, clean up and control of unburned gunpowder, etc.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.467-469
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• 2016

Car smart key system is a technology that allows you to turn activate / deactivate the auto lock through the contact form of electronic keys on the remote control and turn on the ignition by pressing the button. Smart key system is regarded as one of the essential options of the car as it is increasingly convenient to user, but there is no response yet for an attack to this situation. Therefore, in this paper, through an analysis of the amplification attack of a smart key we propose a way to stop the amplification attack and stop the car seized in case the car door opened due to the amplification attack.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.206-209
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• 2010

The visualization device for hybrid rocket is fabricated to investigate the combustion phenomena. Visualization device were composed with ignition system, oxidizer supply system, control system and data acquisition system, combustion visualization system. GOX as oxidizer and HDPE, Paraffin-LDPE Blending, Paraffin sd were used. As results, combustion phenomena and fuel droplet entrainment were observed.