• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.127-133
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• 2008

Since the 1960's, exhaust gas recirculation(EGR) has been used effectively in spark ignition(SI) engines to control the exhaust emissions of the oxides of nitrogen(NOx). The most important requirements for the application of EGR systems to conventional SI engines are controllable flow rate and good dynamic response. In order to evaluate the characteristics of the electronic EGR valve, a test bench which is consisted of blower, heater, air flow meter and driving unit for electronic EGR valve was set up to simulate engine operating conditions. During the tests, the valve actuation parameters were controlled and the valve lifts and flow rates were measured to infer the characteristics of EGR valve. The results confirmed the capabilities of mathematical analysis and it seems that the correction for the valve lift and potentiometer output is necessary to achieve precise control of EGR rates.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.695-700
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• 2006

For the precise superheat temperature control of an air conditioner, an electronic expansion valve may be used instead of a thermal expansion valve. In this paper, technical and economical aspects of expansion valves were studied in order to find out the possibility to use an electronic expansion valve to replace a thermal expansion valve.

• Journal of Power System Engineering
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• v.2 no.3
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• pp.34-40
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• 1998

Performance characteristics of a refrigeration systems with various expansion valves and superheat changes were investigated experimentally. Experimental data have been taken utilizing three different devices; a thermostatic expansion valve, a linear type electronic expansion valve and a solenoid type electronic expansion valve. The data taken from tile three types of expansion valves were discussed with the temperature distribution of each zone in the evaporator and the superheat changes of the evaporator outlet In each zone temperature distribution fluctuated larger with the thermostatic expansion valve than with the electronic expansion valves. The optimum superheat ranged from $5^{\circ}C\;to\;15^{\circ}C$, and the superheat with the thermostatic expansion valve showed hunting phenomenon, which affected the evaporating and condensing temperature.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.3
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• pp.160-166
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• 2016

This study proposes the development and performance evaluation of electronic proportional control valve having an LVDT. The electronic proportional control valve is composed of hydraulic valve, proportional solenoid and controller. LVDT is to reduce the steady state error for the reference input of the controller by the feedback signal to detect the displacement of the spool. Designed LVDT is applied to the common proportional valve. In order to evaluate the performance of the developed valve, the hydraulic test equipment was developed and flow tests were carried out. From experimental results, it was proved that the hysteresis was less than 1% based on the maximum flow rate.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.8
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• pp.746-756
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• 2001

An experimental study was conducted to investigated the effect of refrigerant flow control on the performance of a variable-speed heat pump operating in both cooling and heating mode. For this purpose, cooling and heating capacity, EER and refrigerant mass flow rate corresponding to an electronic valve as well as a capillary tube were measured as functions of compressor speed, length of capillary tube (or valve opening of the electronic valve), refrigerant charge, and outdoor temperature. From the comparison of experimental results, it was found that the performance variation due to the electronic valve opening became significant as the operating conditions(outdoor temperature and compressor speed) deviated from the standard condition at which heating capacity and EER were rated for the indicated capillary tube.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.2
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• pp.282-288
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• 2010

The paper presents the characteristics of capacity control of variable speed water cooler with the electronic expansion valve open/close degree. It is a preliminary study on the optimum control of the water cooler system using a variable speed compressor controlled by inverter. The electronic expansion valve controlled by the variation of compressor speed maintains the constant degree of superheat at the evaporator outlet, which aims to find the degree of superheat obtaining the optimum refrigeration effect. The investigation indicates that there is a point achieving the maximum cooling capacity by the variation of the electronic expansion valve open/close degree with constant compressor speed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.2
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• pp.163-171
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• 2006

In order to control multi-zone temperatures, a multi-type air-conditioning system may be used. In this study, control algorithms for the compressor and the electronic expansion valve of a multi-type air-conditioning system were developed by using fuzzy logics. The compressor control algorithm was composed of a compressor pressure setpoint algorithm, a compressor pressure setpoint reset algorithm, and a compressor frequency setpoint algorithm. The electronic expansion valve control algorithm was composed of an indoor temperature control algorithm, and a superheat control algorithm. These algorithms were applied to a multi-type air-conditioning system. Test showed good results for the control of a multi-type air-conditioning system.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.469-473
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• 2005

Capacities of a tandom-type air-conditioner may be modulated by turning on/off multiple compressors and adjusting positions of a electronic expansion valve. In this study. control algorithms for compressors and a electronic expansion valve were developed by using fuzzy’ logics. There algorithms were implemented in a test lab and proved to be effective for the control of indoor air temperature and superheat temperature.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.675-680
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• 2006

Capacities of a tandem-type air-conditioner may be modulated by turning on and off of multiple compressors, and adjusting the position of a electronic expansion valve. In this study, control algorithms for compressors and a electronic expansion valve were developed by using fuzzy logics. The pressure control algorithm was also developed for the safe operation of compressors. There algorithms were implemented in a test lab and proved to be effective for the control of indoor air temperature and superheat temperature,

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.159-165
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• 2021

Electronic devices used in the mobile environments fabricated under the plasma conditions in high vacuum system. Especially for the development of advanced electronic devices, high quality plasma as the process conditions are required. For this purpose, the variable conductance throttle valves for controllable plasma employed to the high vacuum system. In this study, we analyzed the effects of throttle valve applications on vacuum characteristics simulated to obtain the optimum design modelling for plasma conditions of high vacuum system. We used commercial simulator of vacuum system, VacSim(multi) on this study. Reliability of simulator verified by simulation of the commercially available models of high vacuum system. Simulated vacuum characteristics of the proposed modelling agreed with the observed experimental behaviour of real systems. Pressure limit valve and normally on-off control valve schematized as the modelling of throttle valve for the constant process-pressure of below 10-3 torr. Simulation results plotted as pump down curve of chamber, variable valve conductance and conductance logic of throttle valve. Simulated behaviors showed the applications of throttle valve sustained the process-pressure constantly, stably, and reliably in plasma process.