• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.137-142
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• 2003

A fundamental study for developing a system of fault diagnosis of a pump is performed by using neural network. The acoustic signals were obtained and converted to frequency domain for normal products and artificially deformed products. The signals were obtained in various driving frequencies in order to obtain many types of data from a limited number of pumps. The acoustic data in frequency domain were managed to multiples of real driving frequency with the aim of easy comparison. The neural network model used in this study was 3-layer type composed of input, hidden, and output layer. The normalized amplitudes at the multiples of real driving frequency were chosen as units of input layer, Various sets of teach signals made from original data by eliminating some random cases were used in the training. The average errors were approximately proportional to the number of untaught data. The results showed neural network trained by acoustic signals can be used as a simple method far a detection of machine malfunction or fault diagnosis.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.81-86
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• 2004

A fundamental study for developing a system of fault diagnosis of a pump is performed by using neural network. The acoustic signals were obtained and converted to frequency domain for normal products and artificially deformed products. The signals were obtained in various driving frequencies in order to obtain many types of data from a limited number of pumps. The acoustic data in frequency domain were managed to multiples of real driving frequency with the aim of easy comparison. The neural network model used in this study was 3-layer type composed of input, hidden, and output layer. The normalized amplitudes at the multiples of real driving frequency were chosen as units of input layer. Various sets of teach signals made from original data by eliminating some random cases were used in the training. The average errors were approximately proportional to the number of untaught data. The results showed neural network trained by acoustic signals can be used as a simple method for a detection of machine malfuction or fault diagnosis.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.3
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• pp.255-263
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• 2018

This paper investigated design requirements for piston pumps, which were used as the power source of light rescue vehicle, and designed a piston pump satisfying such requirements. In order to satisfy the driving specification of the rescue device, the pump needs to be designed using the displacement volume of 110 cc/rev, the pressure of 350 bar and the rotation speed of 2,200 rev/min. The design was verified by flow and structural analyses respectively. The shape of the piston pump was optimized in terms of both flow characteristics and structural stability. A test equipment was also fabricated to verify the developed piston pump and test conditions were established. Finally, the developed piston pump was tested for its performance and operating temperature.

• Transactions of The Korea Fluid Power Systems Society
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• v.7 no.4
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• pp.9-14
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• 2010

Most power steering systems work by using a hydraulic system to turn the vehicle's wheels. The pressure is usually provided by a hydraulic pump driven by the vehicle's engine. A double-acting hydraulic cylinder applies a force to the steering gear, which in turn applies a torque to the steering axis of the road wheels. The flow to the cylinder is controlled by valves operated by the steering wheel ; the more torque the driver applies to the steering wheel and the shaft it is attached to, the more fluid the valves allow through to the cylinder, and so the more force is applied to steer the wheels in the appropriate direction. Since the pumps employed are of the positive displacement type, the flow rate they deliver is directly proportional to the speed of the engine. And for a long time, the type of hydraulic pump pulley was boss welding type. But recently, monolith type driving pulley is widely used. Therefore in this paper we studied the safety of monolith type driving pulley to the extracting force and endurance by FEM analysis and experiments.

• Journal of Biomedical Engineering Research
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• v.5 no.1
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• pp.63-68
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• 1984

The Infusion pump that is widely used in hospital has been designed. This system consists of microcomputer system, stepping motor control part and mechanical part for syringe driving. It has 450mmHg maximum pressure and $\pm$0.5% accuracy, and and especially keep the accent on the electrical and functional safety.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1824-1827
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• 2005

For application to micro fluid control systems such as ${\mu}TAS$ (Micro Total Analysis Systems) and DDS (Drug Delivery Systems), it is very significant to handle precise and minute flow rates with low pressure pulsation. In this study, a novel valveless piezoelectric pump using peristaltic motion with three disk type PZT actuators is presented. The newly devised pump with an effective size of $70mm{\times}60mm{\times}55mm$ has three actuator layers connected in series from inlet to outlet. The PZT actuator has a maximum displacement of 240 ${\mu}m$ and a maximum force of 1.6 N. When the driving voltage for PZT actuators is sequentially applied with a certain phase shift, the pumping is performed by peristaltic motion of liquid volume. The working fluid is shut off without the driving voltage. Three methods for sequential driving are proposed and experimentally investigated. First and second methods utilize an intermittent sinusoidal waveform with phase shift of $90{\circ}\;and\;120^{\circ}$, respectively. Third method uses a rectangular waveform with phase shift of $90^{\circ}$. A controller with multi-phase shifter is designed and fabricated. Then, frequency and voltage-flow rate characteristics and load pressure-flow rate characteristics are experimentally investigated to verify the validity of the developed pump.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.269-275
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• 2005

The engine cooling system for a medium duty V6, 4.5 L diesel engine was modeled with a commercial code, GT-Cool in order to investigate the effect of controllable electric pump on the cooling performance and the fuel economy. The simulation results of the cooling system model with mechanical coolant pump were validated with experimental data. Two different types of electric pumps were implemented into the cooling system model and PID control for electric pump operation was incorporated into the simulation study. Based on the simulation result with electric pump, conventional thermostat hysteresis was modified to reduce pump operation for additional improvement of fuel economy, and then the benefit of electric pumps with modified thermostat hysteresis on fuel economy was demonstrated with the simulation. The predicted result indicates that the cooling system with electric pump and modified thermostat hysteresis can reduce pump power consumption by more than $99\%$ during the FTP 74 driving cycle.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.137-145
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• 2008

In this paper, novel CMOS charge pump having NMOS and PMOS transfer switches and a bulk-pumping circuit has been proposed. The NMOS and PMOS transfer switches allow the charge pump to improve the current-driving capability at the output. The bulk-pumping circuit effectively solves the bulk forward problem of the charge pump. To verify the effectiveness, the proposed charge pump was designed using a 80-nm CMOS process. The comparison results indicate that the proposed charge pump enhances the current-driving capability by more than 47% with pumping speed improved by 9%, as compared to conventional charge pumps having either NMOS or PMOS transfer switch. They also indicate that the charge pump reduces the worst-case forward bias of p-type bulk by more than 24%, effectively solving the forward current problem.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.15 no.2
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• pp.97-122
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• 2011

Fluid dynamics driven by pumping without valves (valveless pumping) shows interesting physics. Especially, the driving function to generate valveless pump mechanism is one of important factors. We consider a closed system of valveless pump which consists of flexible tube part and stiffer part. Fluid and structure (elastic tube) interaction motions are generated by the periodic compress-and-release actions on an asymmetric location of the elastic loop of tubing. In this work, we demonstrate how important the driving forcing function affects a net flow in the valveless circulatory system and investigate which parameter set of the system gives a more efficient net flow around the loop.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.10 s.253
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• pp.1019-1025
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• 2006

Numerical simulations were conducted on the gerotor type oil pump. Three oil pump models having different port and groove shape were considered. Firstly, two original models (baseline & variant.1 model) were simulated in order to validate the accuracy of the simulation results and to better understand the flow characteristics in the pump. It was found that the cavitation phenomenon as well as the teeth tip leakage is most important parameter on the pump performance. Based on the simulation results of the original models, final model (variant.2 model) which has improved port shape and pressure relief valve is suggested to enhance pump performance and to reduce driving torque. The volumetric efficiency and the hydraulic torque of the Variant.2 model is improved 4% and reduced 6.1% each at 2000RPM in experiment.