• Journal of the Korean Institute of Gas
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• v.22 no.1
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• pp.1-8
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• 2018

FCV is installed with a automatic valve attached in an high pressure cylinder to control the hydrogen flow. The supply of hydrogen from the cylinder into the fuel cell stack is controlled via the on/off operation of a solenoid attached to the automatic valve. The solenoid needs to provide the necessary attraction force even at any saturation temperature caused by drive of the vehicle. In this study, the simplified prediction equations for the saturation temperature are suggested. The finite element analysis was performed by steady state technique, according to the boundary condition in order to predict the saturation temperature and attraction force. Finally, the saturation temperature was validated through comparison between the analysis results and measurement results. From the results, the measured saturation temperature $5.9^{\circ}C$ lower with respect to the analysis results. And the error of attraction force ranged from 1.0 to 2.1 N at testing conditions.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.203-206
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• 2005

The objective of study on composite cylinder for alternative fuel vehicle is to develop safe, efficient, and commercially viable, on-board fuel storage system for the fuel cell vehicle or natural gas vehicle that use highly compressed gaseous fuel such as hydrogen or natural gas. This study presents the whole procedure of development and certification of a type 3 composite cylinder of 207bar service pressure and 70 liter water capacity, which includes design/analysis, processing of filament winding, and validation through various testing and evaluation. Design methods of liner configuration and winding patterns are presented. Three dimensional, nonlinear finite element analysis techniques are used to predict burst pressure and failure mode. Design and analysis techniques are verified through burst and cycling tests. The full qualification test methods and results for validation and certification are presented.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.123-129
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• 2005

The unbalance of the power output, noise, and vibration is happened by the disproportionate pressure variation in the cylinder. For this reason, decrease of the pressure in the cylinder and increase of the residual gas effect on the engine performance. If the abnormal combustion is continued, the crack would be occurred in the engine block. And it could be broken down. For the normal combustion of the SI engine, it is important to supply the balanced mixture by each operating condition. In this study, it was tested the combustion characteristics in the cylinder according to the abnormal adjusting of intake & exhaust valve. This test is willing to set a basic data's analysis fur developing an automotive diagnosis system by analyzing the pressure in the cylinder, the output signal of MAP sensor, the exhaust gas, etc.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.405-411
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• 1999

Dynamic effect of gas in exhaust manifold influences the volumetric efficiency of the engine. Especially in case of multi-cylinder engine the shape of exhaust manifold is important for the opti-mum design of exhasut manifold complicated. In this paper the effects of exhaust manifold systems on volumetric efficiency were investigated for the 4 cylinder 4 stroke-cycle diesel engine. Volumetric efficiency was calculated by the method of characteristics. The calculation results coincided well the test results. This study showed that the appropriate position and diameter of exhaust manifold branch are important factors in increasing volumetric efficiency and decreasing pumping loss.

• Journal of Biosystems Engineering
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• v.17 no.1
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• pp.5-17
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• 1992

To develop an analytic method of combustion characteristics in a small sized and single cylinder type diesel engine for a power tiller, 1) the theoritical analysis of combustion gas in engine cylinder was performed based on thermoscience and 2) the computer program which could be used to calculate those values of the apparent burning rate, the heat loss, the gas temperature and the fuel-air equivalence ratio with the experimental cylinder pressure data, was developed. This method would provide the practical and quantative data for the diesel combustion process. Through the use of this method, following details would be obtained: 1) the application in the modeling of combustion process without detail knowledeg of combustion process, 2) the basis for the complete modeling of diesel engine, and 3) the basic information for the design of combustion chamber by the prediction of engine performance.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.1-8
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• 2000

A new method of knock detection in SI engines, using a change of ion concentration in the combustion chamber, was developed. In order to measure in-cylinder ionization current, ionization probes were installed at spark plug and cylinder head of production engine. It was found that the electric current generated by ionized gas in core burned gas region of knocking cycle is between 2 and 10 times larger than that of normal cycle, because the burned gas temperature which is the dominant parameter of a change of ion concentration increases. However, a change of ionization current in boundary region of burned gas is relatively weak. Hence a change of ion concentration in core burned gas region can be used for knock detection.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.1
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• pp.45-53
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• 1983

There exist many kinds of frictions in internal combustion engine such as piston ring and skirt, cam and tappet, bearing friction etc. Among them, the frictions between piston ring, skirt and cylinder are particular. These frictions for motoring test are differ from that of firing test even though the temperature of cooling water and lubricating oil keep identically. The frictions for firing test are increased due to combustion pressure and products. The precise calculation of the friction is difficult. But we can assume that the friction is governed by the viscosity of lubricating oil and gas pressure of cylinder. And the viscosity of lubricating oil is dependant on gas temperature of cylinder, so the piston friction may be governed by gas pressure and temperature of cylinder. In this treatise, we propose the method of evaluating piston friction under the condition of constant engine speed, and we analyzed the behaviours and influence of factors concerned with the piston friction for output correction when the inlet pressure and temperature were varied. The main results are as follows: 1) The behaviours on the inlet conditions for the contact force of the piston rings and the viscosity of the lubricating oil concerned with piston friction are found. 2) The essential point the these behaviours is dependant on the cyclic variation following to the inlet conditions. 3) According to our analysis, It was observed that the viscosity of lubricating oil is more effective than the contact force to the piston rings.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.6
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• pp.72-84
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• 1988

Engine performance is one of the main objectives specified at the beginning of a new engine design project. The cycle simulation for SI engine is based on the zero-dimensional gas exchange model and a heat release expression by Viebe. This program also requires minimum input data and takes only a short time to run. Heat transfer from cylinder transfer formula. The flow coefficient (effective area) is calculated from valve lift using the standard flow coefficient curve and engine friction is calculated from the Millington and Hartles' engine friction formula. The chemical species considered in burned gas are 6 species CO, CO, H$_{2}$, H$_{2}$O, $O_{2}$, N$_{2}$ and the cylinder pressure, homogeneous cylinder temperature, gas composition and burned fraction are calculated at each crank angle through the cycle. To check the validity and accuracy, experimental study was done with 3 engines for measuring cylinder pressure, indicated mean effective pressure, brake mean effective pressure and air flow rate, etc. Despite its simple assumptions, cycle simulation showes excellent breathing and performance correlation when compared with data of tested engines, and have been proved useful in engine design.

• 한국가스학회:학술대회논문집
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• 2005.05a
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• pp.233-233
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• 2005

• Journal of the Korean Institute of Gas
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• v.22 no.1
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• pp.60-63
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• 2018

This paper presents the FEM analysis results on the strength safety of a gas valve for a LPG cylinder. Based on the FEM analysis, the maximum von Mises stress on the boundary zone between a safety valve and the upper area of the thread is 99.2 MPa for the supplied gas pressure of 3.5 MPa in which the gas valve is fully opened. The maximum von Mises stress of 99.2 MPa is considered as safety value, because that value is lower than the yield stress of a brass material. In this case, the maximum deformation at the upper right part of the pressure regulator is 0.002mm. The maximum deformation zone is not a meaning part of the sealing part such as an O-ring or a diaphragm of a gas valve and a pressure regulator. The proposed hybrid gas valve model in which is integrated with a conventional cut-off valve and a pressure regulator is recommended as a gas leakage free mechanism and minimized compact size for a LPG cylinder.