• Transactions of The Korea Fluid Power Systems Society
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• v.2 no.2
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• pp.8-13
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• 2005

This paper investigates a fast, accurate and inexpensive hydraulic motor speed control system using high speed on-off solenoid valves. In order to retain the advantages of the two position valve and obtain better performance, the valves are operated by pulse width modulation(PWM) control. PWM signal is generated from a LabWIEW program in microcomputer in order to set up various duty ratio and frequency of carrier wave in PWM signal with varying system parameters. As the results of experiments, the speed control of a hydraulic motor was successfully implemented using on-off solenoid valves. In order to attenuate the pressure ripple and speed variation due to discontinuously controlled flow through the on-off valves, a resonator hose fabricated for automobile power steering system was connected between the valve and a hydraulic motor. From experimental results obtained in the hydraulic motor system with a resonator hose, it was ascertained that the resonator hose showed excellent performances in reducing pressure ripple and motor speed variation.

• Journal of Drive and Control
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• v.11 no.1
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• pp.26-34
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• 2014

• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.1998-2008
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• 2020

Solenoid operated valves (SOV) play important roles in industrial process to control the flow of fluids. Solenoid valves can be found in so many industries as well as the nuclear plant. The ability to be able to detect the presence of faults and predicting the remaining useful life (RUL) of the SOV is important in maintenance planning and also prevent unexpected interruptions in the flow of process fluids. This paper proposes a fault diagnosis method for the alternating current (AC) powered SOV. Previous research work have been focused on direct current (DC) powered SOV where the current waveform or vibrations are monitored. There are many features hidden in the AC waveform that require further signal analysis. The analysis of the AC powered SOV waveform was done in the time and frequency domain. A total of sixteen features were obtained and these were used to classify the different operating modes of the SOV by applying a machine learning technique for classification. Also, a deep neural network (DNN) was developed for the prediction of RUL based on the failure modes of the SOV. The results of this paper can be used to improve on the condition based monitoring of the SOV.

• Journal of Aerospace System Engineering
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• v.1 no.3
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• pp.7-12
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• 2007

As a main part of an utility helicopter, the APU(Auxiliary Power Unit) has a solenoid valve system operated with a torque motor, which controls the flow rate in the fuel supply system. In this paper, we solved the Maxwell potential equations to analyze the electromagnetic force in the torque motor, and some additional analytic methods are used to compute the quantity of torque produced by the torque motor for the given circuit current. For the convenience, small displacement is assumed, and only magneto-static problem is considered for the two-dimensional cross section. The result will be compared with the three-dimensional analysis that will be studied in the near future.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.387-394
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• 2017

This paper develops a pump system for patient with chronic pain or cancer. The pump module is consists of two micro-valve and membrane. The micro-valve is operated by a solenoid. With two solenoid valves which are connected via a drug transport line, the inlet and outlet are completely blocked. A silicon rubber membrane located between the two valves makes the flow-rate constant without any backflow. This pump module can control the flow-rate of drugs by controlling the time that the valves are opened and closed. The reservoir consists of a drug chamber and a gas chamber. As the gas chamber encloses the drug chamber, propellant gas which is injected into the gas chamber pressurizes the drug chamber regardless of volume of the drug chamber. To design the pump module, analysis a constant efficiency test, and accuracy test for the pump module were conducted.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1122-1126
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• 1991

As microcomputers have become widespread and the high speed solenoid valves have been developed, digitally controlled hydraulic systems are used in many applications. This study deals with position control of hydraulic cylinder operated by two port 3-way high speed solenoid valve using a self-learning strategy. This was done by developing a control algorithm for the microcomputer which always automatically adjust the length of control pulse to the optimum value in accordance with the error regardless of changes in the operating condition and physical differences between components. Tests carried out in the laboratory indicate that a positional accuracy could be improved.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.183-188
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• 2014

Solenoid operated electromagnetic control valve (ECV) using in an external variable displacement swash plate type compressor is widely used for air conditioning control system because of its low energy consumption and high efficient characteristics. ECV controls the entire vehicle air conditioning system by means of a pulse width modulation (PWM) system that supplied from an external controller. Different pressure ports located within ECV has important functions to control the air/refrigerant flow through its internal passages. The flow paths are preciously maintained with acceptable ranges of leakage (gap) between the parts inside it which is followed by effective design and critical dimensioning of its internal features. Therefore, it saves energy losses from the solenoid operation as well as ensures the balance of forces within it. The research paper highlights analysis of the leakages (at different pressure ports) and dimensioning tolerance factors that affects the ECV performance.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.2
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• pp.81-91
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• 2000

Dynamic models of line regulator valve(LRV) and ratio control valve (RCV) are obtained for an electronic controlled CVT. LRV and RCV are operated by variable force solenoid(VFS). Considering the CVT shift dynamics, oil pump's efficiency and saturation characteristics of VFS, simulations are performed and compared with test results. Simulation results are in good agreement with the experiments, which shows the validity of the dynamic models of LRV and RCV obtained. In addition, the effects of the orifice size in the exhaust port of RCV are investigated. Simulation results show that as the orifice size decreases, the residual pressure in the primary actuator increases which insures the large torque transmission capacity, meanwhile the duration time for the downshift increases.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.43-51
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• 1998

Most of fuel-injection system operated with mechanical methods are difficult to control the injection quantity and injection timing as well as injection rate exactly. Moreover high pressure injection scheme is never be realized with conventional one. On the other hand, serious air pollution can be lessened with injection system equipped with those functions. Therefore, electronically controlled Unit Injuctor(UI) appeared to satify above mentioned desires. However, it is still difficult that the most important part, especially solenoid valve, is analyzed precisely, because of the existence of complex combination of electromagnetics, electrics and dynamic problems. In this study, experimental and theoretical analysis are accomplished for understanding of solenoid valve characteristics and further its design. As the result, the follows are obtained 1) As the increase of wire diameter, the response time became shorter and optimal inductance existed in relative with the response time and wire diameter. 2) According to increasing input voltage, the traction force increased, otherwise the response time was shortened. 3) As the increase of armature stroke, the traction force decreased and the response time became longer.

• Journal of the Korean Institute of Gas
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• v.26 no.1
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• pp.1-6
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• 2022

This paper is a purpose to study and analyze the engine starting failure examples for LPG car. The first example, the researcher verified the phenomenon that didn't supply the fuel because of filter clogging by fine alien substance in the gas valve line when he inspected the emergency cutting valve. The second example, there was no the influence of gas leakage when the solenoid operated at first. But the damage part of solenoid assemblying face wad downed a durability according to running a valve. Eventually, the researcher checked on the phenomenon of engine stopping by no gas feeding in solenoid because of leaking of gas. The third example, the researcher sought that the wiring sheaths of connector fin between EGR 10A fuse and LPG switch verified the burn-out phenomenon due to the bad contacting as tension damage produced the overheating. Therefore, the manager of a car has to do pre-inspection no producing electric failure and he must maintain his car with optimum condition.