• Journal of KIISE:Computing Practices and Letters
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• v.8 no.6
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• pp.727-735
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• 2002

In this paper, we design and implement a MPLS based IP-VPN service module as an application for ACE2000 MPLS system. ACE2000 MPLS VPN service module has been developed using the BGP4 extension protocol. The IP-VPN service module supports differentiated QoS using the MPLS traffic engineering. In addition, it offers a path protection mechanism and the restart mechanism of MPLS system and forwarding engine for supporting a highly reliable service.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.4
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• pp.912-919
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• 2001

Improvement of the atomization characteristics by adopting the air-shrouded injector has been considered as one of the important methods for decreasing HC emissions in SI engines. Thus, in this study to develop air-shrouded injector with a finer spray, atomization characteristics of differ-ent types of commercial air-shrouded injectors were investigated through the spray imaging and the drop size measurements. As a results, it was found that the internal mixing type of air-shroud-ed injector had a good atomization characteristics. But, a number of large droplets were found in the internal mixing type commercial injector, this shortcoming was improved by adopting the thread type air passages in the air nozzle.

• Journal of IKEEE
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• v.23 no.4
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• pp.1230-1235
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• 2019

In this paper, we have developed sensor composited heater of 2-pin, and unified the fuel filter. In order to evaluate the performance of the 2-pin sensor composited fuel heater, we have make of the low temperature fluidity system. The one measure and analysis the electrical and oil flow quantity characteristics at an input and out port of 2-pin sensor composited fuel heater. Especially, in the characteristics verification elements of the proposed goods, we use the test chamber for the temperature variable and oil flow quantity test, and designed an embedded system for interfacing an engine. By interfacing both user and the system, it support an experimental and date gathering function in 2-pin sensor composited fuel filter. And then test the temperature, oil pressure, electrical characteristics and oil flow quantity in variable status from - 30 ℃ to + 80 ℃. These can help us to determine the quality and performance of elementary goods.

• Journal of the Korean Institute of Gas
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• v.19 no.1
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• pp.1-5
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• 2015

In general, natural gas is used as GHP(Gas Engine Driven Heat Pump) fuel. On this study, the influences of different natural gas heating value on GHP were evaluated. As a result of engine test & field test using low heating value gas($9,800kcal/Nm^3$) as fuel, the engine power was reduced slightly, however the performance of start-up, the stability of operation and the characteristics of emission gas were almost similar. So it is considered that the normal operation of GHP is possible without any tuning when the low heating value($9,800kcal/Nm^3$) of natural gas was used as fuel.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.1
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• pp.65-72
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• 2014

Turbine rotor-pyrostarter coupled test was performed for the verification of thermo-structural suitability of a turbopump turbine. Newly developed solid propellant and design concept were used in pyrostarter development. In case of turbine rotor, rotor configuration modification and post EDM machining process are adopted in rotor manufacturing respectively for the thermal stress relief and the surface integrity improvement on the blade surfaces. In the test, combustion gas of pyrostarter was directly ejected from the nozzles and impinged on the stationary turbine rotor specimen through the identically shaped flow passage of turbopump. Three kind of thermal load - design to extreme condition - test were performed and no damages were found on the turbine rotor specimens.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.619-626
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• 2016

The new 1.4 L turbocharged LPG direct injection (T-LPDI) engine is presented in this paper to improve the fuel efficiency of the vehicles installed with the 2.0 L LPG port fuel injection (LPI) engine, while maintaining the performance as a downsizing concept for the new engine platform development. Firstly, the return type high pressure LPG fuel supply system is designed and mounted in the new 1.4 L T-LPDI engine. As a result, this new engine shows a much better WOT performance and approximately 8 % of improved fuel economy level, as compared to the 2.0 L LPI vehicle. Secondly, the LPDI engine specific optimized design for high pressure fuel components and fuel injection control strategies are proposed and evaluated in order to overcome the restartability problem in a heat-soaked condition called the vapor lock phenomenon. Consequently, these experimental results illustrate a great potential for the developed 1.4 L T-LPDI engine as a possible substitute for the 2.0 L LPI engine.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.76-89
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• 2018

The distribution of the combined heat and power system is active as a solution to the instability of energy supply and environmental pollution caused by continuous industrial development. In Korea, the safety standards for combined heat and power system using a gas engine are insufficient therefore the study on this is needed. In this study, the safety performance and structural/material assessment items of domestic and international standards applied to the combined heat and power system were analyzed to carry out a standardization study on safety performance applicable to 20 kW gas engine combined heat and power system. In addition, the safety performance assessment (plan) of the gas engine combined heat and power system was derived by performing risk analysis and risk assessment using HAZOP. Assessment items include engine ignition systems related to safety performance, piping tight performance, watering and temperature rise performance, combustion performance, electrical efficiency, thermal efficiency, overall efficiency and humidity performance. Gas and water pipes, gas control and shut-off valves, durability, heat resistance, and cold resistance of metal or non-metallic materials related to the structure and materials of the gas engine combined heat and power systems.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.4
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• pp.104-111
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• 2019

Staged combustion cycle engines exhibit higher combustion performance compared with open cycle engines with a gas generator. An advanced research of the staged combustion cycle engine is going on for the next program following the KSLV-II program. Various experiments have been carried out for the technology demonstration model, TDM0A and TDM0B. The experiments on the combustion performance are aimed to understand the engine start condition and combustion characteristics. They also aim to develop the oxidizer-rich pre-burner and the combustor of the staged combustion cycle engine. The engine-shaped model, TDM1A is fabricated based on the experimental data. The combustion experiment of the TDM1A shows that the combustion pressure of the combustor is approximately 91 bar and the turbine rotation is approximately 28,00 rpm. The result is stable and satisfies the development requirements. The present paper reports on the development process and characteristics of engine models from TDM0A to TDM1A.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.7-13
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• 2014

As the interest on the air pollution is gradually rising up at home and abroad, automotive and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward various main issues : whether PM emissions should be regulated for diesel and gasoline vehicles and whether gasoline and LPG powered vehicles can be further neglected from PM emission inventories. Finally, the greenhouse gas ($CO_2$, $CH_4$, $N_2O$) regulation has been discussed including automotive emission regulation. The greenhouse gas and emissions (PM) particle of automotive had many problem that cause of ambient pollution, health effects. This paper discussed the influence of LPG fuel on automotive cold startability and exhaust emissions gas. Also, this paper assessed emission characteristics due to the test temperature. These test temperature were performed by dividing the temperature of the test mode and the lowest local temperature in winter. Through this study, the correlation of cold startability, exhaust emission and greenhouse gas emission was analyzed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.703-709
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• 2017

Korea Utility Helicopter(KUH) is a project to replace the aging helicopter presently being operated by the military with a domestic helicopter. The auxiliary power unit is a device that supplies emergency power to the system by an alternator installed when the main generator fails and the start motor converts the electrical energy of the battery into mechanical rotational energy to rotate the auxiliary power unit engine. With continuing power and operation, defects of the starting motor were found and improvements were carried out to solve it. In the failure mode analysis, the causes of possible defects were classified into 5 categories. Analysis of the 5 factors revealed that the main cause of defects is mechanical wear, which was found to be related to spring pressure. 250 tests were conducted through the theoretically determined pressure and regression analysis was performed with 4 sampling.The results showed that pressure was related to wear rate. In conclusion, early wear and breakage due to wear can be controlled through spring force and test showed the prediction of wear and the validity of the result were confirmed.