• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.201-201
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• 2000

Recently in the design of fuel tanks(launch vehicle, ship, automobile) which transport a large amount of liquid in the cargo holds, the structural damage due to liquid-sloshing becomes an important problem. The impact pressure from sloshing is most violent when the liquid motion of a partially filled tank is in resonance with the motion of a system. In this paper, the sloshing natural periods in liquid tanks are estimated for partially filled tanks with various geometries. In addition to, controlled for a launch vehicle with liquid sloshing effect by PD controller and sloshing filter The PD gain and sloshing filter parameter arc determined by optimal algorithm.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.4
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• pp.345-350
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• 2020

Hydrogen is an green energy without pollution. Recently, fuel cell electric vehicle has been commercialized, and many studies have been conducted on hydrogen tanks for vehicles. The hydrogen tank for vehicles can be charged up to 70 MPa pressure. In this study, the change in filling time, pressure, and temperature for each hydrogen level in a 59 L hydrogen tank was predicted by numerical analysis. The injected hydrogen has the properties of real gas, the temperature is -40℃, and the mass flow rate is injected into the tank at 35 g/s. The initial tank internal temperature is 25℃. Realizable k-epsilon turbulence model was used for numerical analysis. As a result of numerical analysis, it was predicted that the temperature, charging time, and the mass of injected hydrogen increased as the residual capacity of hydrogen is smaller.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.2
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• pp.157-166
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• 2017

The Fuel Cell Electric Vehicle(FCEV) is recently evolving into a new trend in the automobile industry due to its relatively higher efficiency and zero greenhouse gas(GHG) emission in the tailpipe, as compared to that of the conventional internal combustion engine vehicles. However, it is important to analyze the whole process of the hydrogen's life cycle(from extraction of feedstock to vehicle operation) in order to evaluate the environmental impact of introducing FCEV upon recognizing that the hydrogen fuel, which is used in the fuel cell stack, is not directly available from nature, but instead, it should be produced from naturally available resources. Among the various hydrogen production methods, ${\sim}54.1%^{8)}$ of marketed hydrogen in Korea is produced from naphtha cracking process in the petrochemical industry. Therefore, in this study, we performed a well-to-wheels(WTW) analysis on the hydrogen fuel cycle for the FCEV application by using the GREET program from the US Argonne National Laboratory with Korean specific data. As a result, the well-to-tank and well-to-wheel GHG emissions of the FCEV are calculated as 45,638-51,472 g $CO_2eq/GJ$ and 65.0-73.4 g $CO_2eq/km$, respectively

• International Journal of Automotive Technology
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• v.7 no.1
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• pp.9-15
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• 2006

Prediction of the performance of a carbon canister in vehicle evaporative emission control system has become an important aspect of overall fuel system development and design. A vehicle's evaporative emission control system is continuously working, even when the vehicle is not running, due to generation of vapors from the fuel tank during ambient temperature variations. Evaporative emissions from gasoline powered vehicles continue to be a major concern. The objective of this paper is to clarity the flow characteristics and other such fundamental data for the canister during loading and purging are needed, and this data will prove valuable in the development of the canister. This paper is to evaluate the relationship between carbon canister condition and engine performance during engine operation, and the effects of evaporative emissions on the engine performance were investigated.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.1
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• pp.47-60
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• 2021

Hydrogen is a next-generation energy source, and according to the roadmap for activating the hydrogen economy, it is expected that industries to stably produce, store, and transport of hydrogen as well as the supply of hydrogen fuel cell vehicles will be made rapidly. Accordingly, safety measures for accidents of hydrogen vehicles in confined spaces such as tunnels are required. In this study, as part of a study to ensure the safety of hydrogen fuel cell vehicles in road tunnels, a basic investigation and research on the risk of fire and explosion due to gas leakage and hydrogen tank rupture among various hazards caused by hydrogen fuel cell vehicle accidents in tunnels was conducted. The following results were obtained. In the event of hydrogen fuel cell vehicle accidents, the gas release rate depends on the orifice diameter of TPRD, and when the gas is ignited, the maximum heat release rate reaches 3.22~51.36 MW (orifice diameter: 1~4 mm) depending on the orifice diameter but the duration times are short. Therefore, it was analyzed that there was little increase in risk due to fire. As the overpressure of the gas explosion was calculated by the equivalent TNT method, in the case of yield of VCE of 0.2 is applied, the safety threshold distance is analyzed to be about 35 m, and number of the equivalent fatalities are conservatively predicted to reach tens of people.

• Progress in Superconductivity and Cryogenics
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• v.16 no.4
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• pp.71-77
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• 2014

For a long-term space mission, filling process of cryogenic liquid propellant is operated on a space vehicle in space. A vent process during transfer and filling of cryogenic propellant is needed to maintain the fuel tank pressure at a safe level due to its volatile characteristic. It is possible that both liquid and vapor phases of the cryogenic propellant are released simultaneously to outer space when the vent process occurs under low gravity environment. As a result, the existing filling process with venting not only accompanies wasting liquid propellant, but also consumes extra fuel to compensate for the unexpected momentum originated from the vent process. No-Vent Fill (NVF) method, a filling procedure without a venting process of cryogenic liquid propellant, is an attractive technology to perform a long-term space mission. In this paper, the preliminary experimental results of the NVF process are described. The experimental set-up consists of a 9-liter cryogenic liquid receiver tank and a supply tank. Liquid nitrogen ($LN_2$) is used to simulate the behavior of cryogenic propellant. The whole situation in the receiver tank during NVF is monitored. The major experimental parameter in the experiment is the mass flow rate of the liquid nitrogen. The experimental results demonstrate that as the mass flow rate is increased, NVF process is conducted successfully. The quality and the inlet temperature of the injected $LN_2$ are affected by the mass flow rate. These parameters determine success of NVF.

• Journal of the Korean Institute of Gas
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• v.24 no.1
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• pp.23-32
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• 2020

It is not easy to fully fuel high pressure(70 MPa) hydrogen in a hydrogen vehicle tank quickly. This is because the temperature inside the tank rises rapidly due to heat caused by the Joule-Thomson effect, etc. So fueling protocols such as SAE J2601 in the U.S. and JPEC-S 0003 in Japan appeared. However, there is a problem with these protocols that a number assumption are introduced and the content is too complex and limited in scope. This study was conducted to develop a new protocol based on complete real-time communication. In this study, the hydrogen fueling simulation program were used to examine how the pressure ramp rate affects the temperature and pressure rise in the tank and the fueling flow rate. The results confirmed that the first parameter to be considered in determining the pressure ramp rate is the temperature of the tank.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.166-174
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• 2014

Fuel injection pressure has steadily increased in diesel engines for the purpose of improving fuel efficiency and cleaning exhaust gas, but it has now reached a point, where the cost for higher pressure does not warrant additional gains. Common rail systems on modern diesel engines have fuel pumps that are mechanically driven by crankshaft. The pumps actually house two pumping module inside: a low pressure pump component and a high pressure pump component. Part of the fuel compressed by the low pressure component returns to the tank in the process of maintaining the pressure in the common rail. Since the returning fuel represents pumping loss, fuel economy improves if the returned fuel can be eliminated by using a properly controled electrical fuel pump. As the first step in developing an electrical fuel pump the fuel supply system on a 6 liter diesel engine was modeled with AMESim to analyze the workload and the fuel feed rate of the injection pump, and the results served as basis for selecting a suitable servo motor and a reducer to drive the pump. A motor controller was built using a DSP and a program which controls the common rail pressure using a proportional control method based on the target fuel pressure information from the engine ECU. A test rig to evaluate performance of the fuel pump is implemented and used to show that the newly developed electrically driven fuel pump can satisfy the fuel flow demand of the engine under various operating conditions when the rotational speed of the pump is adequately controlled.

• Tribology and Lubricants
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• v.22 no.6
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• pp.329-334
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• 2006

In CNG (Compressed natural gas) fuel supply line, whose main components are receptacle and check valve are used to charge high pressure gas to the tank of NGV (Natural gas vehicle). It is reported that the seal is separated occasionally form valve seat and results in blockage of gas flow. In this paper, MARC is used to investigate the reasons of seal separation and suggest design improvements. The static gas pressure distributions acting on the seal which calculated using FLUENT are considered to investigate accurate seal deformation behaviors. Deformed seal shapes are obtained for various amounts of seal interference and its location, gas pressure distributions and Young's modulus of the rubber used. The results showed that the reasons of seal separation problems are verified theoretically, and suggested examples of new design method. Therefore the present numerical methods can be applied in designing and performance analysis of rubber seals adopted in high pressure fluid machineries.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.98-103
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• 2015

A flow passage opening device utilizing an acceleration follow-up technique allows fuel to flow continuously through a pressurized fuel tank system. It is very difficult to test the device in a real flight situation because of severe test condition and a cost problem. In this paper, therefore, the results of a basic negative g test conducted by low-speed airplane are compared with RecurDyn simulation. Dynamic behavior of the device in total flight profile of a high-speed vehicle is also analyzed by using RecurDyn to predict its performance.