• Proceedings of the KSME Conference
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• 2000.04b
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• pp.892-898
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• 2000

This study is on the development of a new muffler composed of a valve system using an elasticity or spring. The valve system using the elasticity of spring is set along the exhaust-gas flow and designed to work itself alone the driving condition of a engine. By that reason the engine capacity is so enlarged that a muffler with controller sensing exhaust-gas pressure is able to be satisfied to noise reduction and- power enlargement more than conventional muffler. The purpose of this study is to develope the new muffler which has more noise reduction and power enlargement than conventional muffler and electric-control muffler.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.88-90
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• 1994

The permanent magnet type stepping motor is used widly for various devices, such as FA and OA machine. Characteristics of the stepping motor is analyzed using permeance method. Static, dynamic and I step response characteristics of PM type stepping motor for idle air valve is discussed.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2578-2580
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• 2000

A siumlator had been developed and used for reliability verification on medium size steam turbine control programs prior to its actual operation in field. A mathematical model on thermal dynamics pertaining to prime mover steam turbine and electrical generator was realized and included in this simulator. Also, many operating data acquired from fields was utilized in order to decide mechanical and thermal dynamic characteristics such as friction loss, windage loss and inertia. A user can decide closing or opening velocity of steam stop valve and steam regulation valve. This simulator is able to generate steam pressure, turbine speed, electrical power, and power system frequency.

• Solar Energy
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• v.20 no.1
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• pp.63-72
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• 2000

In this study, theoretical simulation method for the steady state characteristics of a refrigeration cycle which consists of one condenser and multi-evaporator (Multi-air conditioner) is presented. The simulation was performed for a typical multi-air conditioning system consisted one outdoor unit with air-cooled condenser, compressor, linear electric expansion valve and bypass circuit and connected three-evaporators (three indoor units). The simulation results are good agreement with those of experiments within 5 $\sim$ 10% at the given system operation conditions which are condensing pressure, evaporating pressure, sub-cooled degree of condenser, superheated degree, discharge temperature of compressor and pulse of linear electric expansion valve.

• Computers and Concrete
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• v.24 no.5
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• pp.437-444
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• 2019

PLC and its expansion module, electric ball valve and cooling pipe, electric heating steel plate and various components of the system, which is used to control test and process data. By automatically adjusting the opening of the valve, the system makes the top temperature and cooling speed develop along the ideal temperature diachronic curve. Moreover, the system enables the temperature difference between inside and surface of test block limited in a given range by automatically controlling the surface board heating. The method of physical simulation test by sandbox with built-in cooling water pipe and heating rod is adopted. On the premise of a given standard value, the operation of the system is checked under different working conditions. Further, an extension of this system is proposed, which enables its application to obtain some thermal parameters when cooperating with numerical simulation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.3
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• pp.189-197
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• 2016

Green vehicles include electric vehicles, natural gas vehicles, and fuel cell vehicles (FCVs). In FCVs, pressure vessels have cylinder valves to control hydrogen flow. These valves should be of high quality in terms of safety because hydrogen is stored at ultra-high pressure in pressure vessels. Hence, safety evaluation of these valves is necessary to secure the safety of the FCV. A structural analysis of the cylinder valve was conducted in this study by using a commercial finite element analysis code. The results showed that the safety factor of valve component ranged 1.06-186.44. After categorizing, the stress components at critical points of the cylinder valve parts were evaluated using the corresponding allowable design criteria in the ASME code. The pressurization cycle test was performed as per the regulation to evaluate the safety of the valve.

• Journal of ILASS-Korea
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• v.19 no.1
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• pp.25-32
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• 2014

For reduction of $CO_2$ emission emitted from combustion engine, the developed nations have been focused on R&D of hybrid electric vehicle. Further more, many automobile companies are researching on various techniques related to engine used in HEV to enhance fuel economy. One of key techniques is miller cycle that control a valve timing to reduce compression stroke for saving energy and increase expansion stroke for high power. In this study, it was investigated the in-cylinder flow characteristics of miller cycle with variable intake valve timing by using the ANSYS simulation code. For simulation, the key analytic parameter defined as intake valve closing timing and cam profile. As main results, it was shown that LIVC cause a lower pressure inside cylinder and had better control turbulence intensity.

• Journal of Energy Engineering
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• v.17 no.4
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• pp.212-217
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• 2008

This study carried out the safety evaluation of non-refillable butane can for portable gas range equipped with relief valve for prevention of explosion. The can is heated by electric heater at the real using condition and the extreme condition after installing at a portable gas range for checking the operating pressure and the evaluating suitability of releasing flux. And the possibility of fire or explosion was tested when the gas was released from the relief valve at the real condition. As a result of this safety evaluation test, a non-refillable butane can with relief valve prevents the can from exploding by control of internal pressure.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.1-10
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• 1999

The engine exhaustive valve became essential as the important element. The dissimmilar welding method of exhaustive valve head to stem was asked for manufacturing the engine exhaustive valve, for which the electric resistance are welding has been conventionally used, resulting in poor quality of the welded joint. In this paper, not only the development of optimizing of friction welding with more reliability and more applicability but also the development of in-process real-time weld qudlity(such as strength and toughness) evaluation technique by acoustic emission for friction welding of the engine exhaustive valve(SUH3-SUH35 dissimilar steels) were perfomed. The high temperature(500, 500, 600$^{circ}$C) creep properties prediction of the friction welded joint of SUH3-SUH35 was investigated relating to the initial strain meethod(ISM) as a new approach, resulting in obtaining an experimental equation of creep life prediction.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.79-84
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• 2011

In general, a valve body of the automatic transmission(AT) is controlled by the clutch, the brake and lubricating oil flow in a hydraulic system and lubricant flow for each valve can be adjusted independently. To increase the lifetime of AT, the lubrication flow rate in a valve body for a 6 speed AT based parallel hybrid electric vehicle must be provided with proper oil distribution and control. In this study, we carried out several experiments without the inner parts of AT and with a AT assembly. The variation of the flow rate on oil temperature and pressure between an oil supply port and the outlets of the lubrication port was evaluated and analyzed. In the case of AT without the inner parts, it was evident that as the oil required for an operation of the clutch and brake was discharged from the outlet port, the flow rate from each lubrication port is decreased. However, the flow rate of the AT assembly was slightly increased. In addition, the lubrication flow rate was increased with increasing the oil temperature, and also it was reduced with increasing the oil pressure. Details of the resulting data are discussed.