• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.9
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• pp.810-817
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• 2001

Performance of a water-to-water multi-type heat pump system using R22 which has tow indoor units has been investigated experimentally. The refrigerant flow rate of each indoor unit was regulated by an electronic expansion valve and the total refrigerant flow rate of the system was controlled by a variable speed compressor. In the system, evaporator outlet pressure of refrigerant and outlet temperatures of secondary fluid from indoor units were selected as control variables. Experiments were executed for both cooling and heating modes using PID control method with fuzzy logic, and results of the test are compared with a classical PID method. In the case of PID control with fuzzy logic, the fuzzy control rules corrects PID parameters each time. Results show that PID control with fuzzy logic has the merits of quick response and reduced overshoot.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.67-73
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• 2013

This experimental work described the effect of flow control valve type on the performance of wobble plate type fuel pump for the stable DME fuel supply. In order to study this, different four types of flow control valves (ITV, SCV, IMV and MPROP) were installed on the wobble plate fuel pump, and fuel flow rate, torque, and temperature variation of pump were investigated under various operating conditions by using pump performance test system. It was revealed that wobble plate type fuel pump worked well with ITV and SCV control valve, and the flow rate and torque of fuel pump was in proportion to the value of valve open duty. The maximum flow rate and torque of fuel pump were achieved around the 50% duty of control valve. Temperature variation at all pump measuring points were under $60^{\circ}C$ which is acceptable.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.160-170
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• 2006

If hydraulic pump controlled by mechanical type regulator has more than one control function, the construction of regulator will be very complicated and control performance falls drastically. It is difficult to have more than one control function for hydraulic pump controlled by electronic type hydraulic valve due to the inconsistency of controllers. This paper proposes a multi-function control technique which controls continuously flow, pressure and power by using EPPR(Electronic Proportional Pressure Reducing) valve in swash plate type axial piston pump. Nonlinear mathematical model is developed from the continuity equation for the pressurized control volume and the torque balance for the swash plate motion. To simplify the model we make the linear state equation by differentiating the nonlinear model. A reaction spring is installed in servo cylinder to secure the stability of the control system. We analyze the stability and disturbance by using the state variable model. Finally, we review the control performances of flow, pressure and power by tests using PID controller.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.12
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• pp.75-81
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• 2008

A robust controller is proposed for regulating effectively the pressure of control cylinder of swash plate type variable displacement axial piston pump. In order to design a precise and robust pressure control system, a mathematical model for swash plate control system is identified by the signal compression method. Based on the identified mathematical model, an $H_{\infty}$ robust swash plate controller is designed which is robust to the variation of the load pressure. The precise and robust swash plate control characteristics are verified by experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.316-322
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• 2007

The EHA(Electro-hydrostatic Actuator) reveals completely different characteristics from the conventional valve-controlled Electro-hydraulic actuators. In this paper, its mathematical model including nonlinear elements was derived to be verified by experiments. Based on this, a simulation program was developed for the EHAs consisting of an electric motor driven hydraulic pump, pipe lines and a cylinder. The influence of important design parameters such as peak motor torque and rotational inertia moment of the hydraulic pump on control performance was investigated, where the test condition was intentionally selected so that the motor torque was saturated during the transient phase. As a result, design requirements for improving the control accuracy under full speed operation conditions of the EHAs were investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.674-678
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• 2007

기술수준의 발달로 인해 건물이 대형화 고층화됨에 따라 높은 양정의 펌프를 사용하고 있으며, 배관계통을 대부분 전자식 밸브를 채택하여 입상급수라인의 수충격 현상이 대두되어 수충격 현상제어를 위한 여러 방법들이 시행되고 있다. 본 연구는 수충격 현상을 제어하는 방법 중 수충격 방지기를 이용하여 입상급수라인의 수충격 현상의 제어를 효과적으로 제어할 수 있었다. 향후 본 연구를 계속 진행 시켜나감에 따라 수충격 현상의 제어에 큰 성과를 거둘수 있을 것으로 판단된다.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.351-357
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• 2019

This research is automatic Wet Pipe Sprinkler System, dry pipe Sprinkler System, preaction Sprinkler system, vacuum Sprinkler system, deluge Sprinkler system, etc., key components of each Sprinkler system, verve valve, valve, etc. This is to simplify the various processes of the manufacturing process into a single process to create an environment in which a single machine can simultaneously produce a standardized product, thereby improving the price competitiveness of the product, reducing the cost of maintaining the product, and making it more adaptable to the new sprinkler system that is developed in the future. Automatic Wet Pipe Sprinkler System, desipe Sprinkler System, preaction sprinkler system, vacuum Sprinkler system, deluge Sprinkler system, both types of existing Sprinkler system, only replace the primary and secondary tubing valves.It has the advantage of being easy to apply to the lower system. Legal and institutional research is needed for the commercialization of the Sprinkler system applying the solenoid valve as a future project.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.8
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• pp.19-24
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• 2022

We developed a prototype from the design of a trim, which is the most important in the localization development of a 1500 Ib high-differential pressure-control valve used for boiler feedwater, and measured the flow coefficient, the most basic design data for valves. The following conclusions were drawn. The comparison of the design values of the flow coefficients for the existing X-trim and the multicore trim designed for localization development showed that they were almost identical, and the X-trim value was slightly lower. The comparison of the X-trim and multicore trim based on the valve flow coefficient test showed that they were generally similar, indicating no problem with the design. In the future, we plan to compare and analyze the flow paths for the X-trim and multicore trim via flow analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.464-469
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• 2019

A remote monitoring panel and control system was developed to control various valves and access control chambers, including gas shutoff valves used in CBR(Chemical, Biological and Radiological) facilities. The remote monitoring panel consisted of a main panel installed in the NBC (Nuclear, Biological and Chemical) control room and auxiliary panel installed in the clean room, and the size was divided into pure control and control including CCTV. This system can be monitored and controlled remotely according to the situation where an explosion door and gas barrier door can occur during war and during normal times. This system is divided into normal mode and war mode. In particular, it periodically senses the operation status of various valves, sensors, and filters in the CBR facilities to determine if each apparatus and equipment is in normal operation, and remotely alerts situation workers when repair or replacement is necessary. Damage due to the abnormal operation of each device in the situation can be prevented. This enables control of the blower, supply and exhaust damper, emergency generator, and coolant pump according to the state of shutoff valve and positive pressure valve in the occurrence of NBC, and prevents damage caused by abrupt inflow of conventional weapons and nuclear explosions.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.7 no.1
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• pp.32-37
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• 2011

In this study, control characteristics and energy performance with flow rate control methods were reviewed with the simulation. The heating system is classified such as fan coil unit and HVAC system currently used in buildings with valve control and pump inverter control. The simulation analysis program is made by TRNSYS ver. 15 with the actual data. As a result of this study, the central heating system with pump inverter control decreases electricity energy and reduces gas consumption. Inverter control method shows better performance in comparison with valve control one for energy saving.