• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.44-50
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• 2002

The spray characteristics of GDI(Gasoline Direct Injection) injector affects on engine efficiency and emission of a GDI engine. Thus, many researchers have investigated the spray characteristics and the mixture formation of GDI injector. In this study, it was tried to provide the fundamental data for GDl injector design which effects on the spray macroscopic characteristics such as penetration and spray angle. In addition, the mixture formation analyzed by using entropy analysis. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. The results show that as injection pressure increases but as ambient pressure increases, spray penetration decreases and spray angle doesn't affected by increasing injection pressure and ambient temperature. From the entropy analysis results, we could find that the direct diffusion phenomena is a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially in vaporizing conditions.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.654-661
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• 1999

This is fundamental study to improve performance of the SI engine,. In this study a conven-tional kerosene engine was modified to LPG dedicated engine which can be operated with LPG(Liquefied Petroleum Gas) The modified model were tested in accordance with various compression ratios. Also the engine performance with modified model was compared with the conventional one. The results are sum-marized as follow; 1. In comparison with the conventional kerosene Gasoline engine and LPG dedicated engine can be operated with lower exhaust emission better fuel economy and better thermal efficiency. 2. But is produce a slightly lower brake horse power.

• Journal of Energy Engineering
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• v.17 no.2
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• pp.47-53
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• 2008

The objective of this paper is to clarify the flow characteristic, velocity distribution, pressure loss, and other such fundamental data for the canister during loading and purging. The amount of gas that is loaded increases as the loading rate is decreased and the time increased, and the purging improves as the purge rate is increased. The hydrocarbons that are purged initially have a high concentration, and a large amount is purged. During loading and purging, the temperature initially increases and decreases drastically due to heat generation and heat loss.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.6
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• pp.650-655
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• 2015

A high energy ignition system is essential for lean burn or high EGR gasoline engine, which is getting more and more interest to improve fuel economy. The high energy ignition systems comprise plasma jet, laser beam, corona discharge and so on. In this study, a high energy ignition system using corona discharge is developed and tested in a constant volume combustion chamber. The developed system shows extension of lean limit of propane-air mixture and enhencement of combustion speed. Various shape of corona discharge plugs are also tested and compared in this study.

• Journal of the korean Society of Automotive Engineers
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• v.8 no.1
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• pp.75-86
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• 1986

This paper describes a simulation program of intake and exhaust processes in a 4-stroke S.I. engine and also studies the relationship among various engine parameters under different engine speed and load conditions. This simulation program includes the engine cylinder model for the intake and exhaust processes and its formulation and evaluates the system characteristics such as inlet mass, pumping work and residual gas in the cylinder-which influence on power output, fuel economy and exhaust emissions. In order to evaluate the accuracy of the simulation program, predicted results were compared with the experimental data obtained on the 4-stroke, 4-cylinder gasoline engine and satisfactory agreement was obtained.

• KSBB Journal
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• v.31 no.4
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• pp.193-199
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• 2016

Global warming caused from the heavy consumption of fossil fuel is one of the biggest problems to be solved. Biofuel has been gained more attention as an alternative to reduce the consumption of fossil fuel. Recently, butanol produced from the genus Clostridium has been considered as one of the promising alternatives for gasoline, fossil based fuel. Nevertheless, the lack of the genome-engineering tools for the genus Clostridium is the major hurdle for the economic production of butanol. More recently, genome engineering tools have been developed for metabolic engineering of butanol-producing Clostridium species, which includes genome scale network model and genome editing tools on the basis of mobile group II introns and CRISPR/Cas system. In this study, the genome engineering tools for butanol-producing Clostridium species have been reviewed with a brief future perspective.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.767-780
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• 2015

Transport biofuels produced from biomass can be substituted for petroleum fuels due to GHG reduction, sustainability and environmental friendly. Mandates and targets of biofuels are announced in the European union, United states and other countries worldwide and promoted by the government policies. This paper reviewed current status of the national biofuels policies and fuel specifications in transport sector. EU biofuels policy shifted and GHG emission reduction became the main focus of the policy. There are specification requirements for biofuels in the U.S. under the RFS2, but there are other polices as well that serve to promote the uptake of biofuels both at the federal and state level. Korea government has allowed 2.3% oxygen in gasoline to come from oxygenates, increased the biodiesel blend mandate from B2 to B2.5 effective from Jul. 31, 2015.

• Journal of Hydrogen and New Energy
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• v.21 no.5
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• pp.435-441
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• 2010

To verify the possibility of a power generation system using biogas from the waste of pig farm for rural electric production, a SI gasoline engine is modified to use biogas fuel and was installed in a 20 KVA power generation system. An electronic speed regulation unit is developed to keep the system speed at 1500 rpm. Experimental investigations have been carried out to examine the performance characteristics of power generation system (such as: system frequency, phase output voltage,$\ldots$). In addition, the operating parameters and output emissions ($NO_x$, HC, and $CO_2$) of biogas-fueled engine are preliminary evaluated and analyzed for the change of system load. Results indicated that the researched power generation system shows a high stability of output voltage and frequency with help of speed regulator. Biogas fuel (mainly $CH_4$ and $CO_2$) has an environmental impact and potential as a green alternative fuel for SI engine and they would not require significant modification of existing engine hardware. Output emissions of biogas-fueled engine are found to be relative low. $NO_x$ emission increases with the increase of output electric power of the power generation system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.10
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• pp.985-993
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• 2012

In this paper, a new method is proposed to estimate the sound pressure generated from gasoline direct injection (GDI) engine. There are many noise sources as much as components in GDI engine. Among these components, fuel pump, fuel injector, fuel rail, pressure pump and intake/exhaust manifolds are major components generated from top of the engine. In order to estimate the contribution of these components to engine noise, the total sound pressure at the front of the engine is estimated by using airborne source quantification (ASQ) method. Airborne source quantification method requires the acoustic source volume velocity of each component. The volume velocity has been calculated by using the inverse method. The inverse method requires many tests and has ill-condition problem. This paper suggested a method to obtain volume velocity directly based on the direct measurement of sound intensity and particle velocity. The method is validated by using two known monopole sources installed at the anechoic chamber. Finally the proposed method is applied to the identification and contribution of noise sources caused by the GDI components of the test engine.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.415-423
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• 2007

This study assessed the characteristic of BTEX (Benzene, Toluene, Ethylbenzene, Xylene) concentration ratios of industrial emission sources and the neighborhoods of industrial area, fuel such as gasoline, light oil, LPG, and similar gasoline, and ambient air in Daegu. The BTEX in aromatic compounds was the most abundant VOC in Daegu. The BTEX ratios were (0.2:2.6:1.0:1.8) for the neighborhoods of industrial area, (2.6:11.3:1.0:1.2) for residential area, (2.2:11.0:1.0:1.6) for commercial area, (1.0:14.9:1.0:1.3) for industrial area, and (0.2:2.6:1.0:1.8) for the neighborhoods of industrial area. Average BTEX ratios in Daegu were B/T ratio (0.1), B/EB ratio (1.5), B/X ratio (1.1), T/EB ratio (12.6), T/X ratio (10), EB/X ratio (0.7), Expecially, B/T ratio in Daegu was similar as the other cities, Bangkok, Manila, and Hongkong. Comparing other cities with B/T ratio, the main sources of VOC were vehicular exhaust and emission of industrial facilities. Furthermore, BTEX correlation were evaluated at the emission sources and regional areas. Results showed that correlation coefficient values of emission sources, fuels and neighborhood of industry were significant magnitude above 0.65(p<0.01). Also, there showed highly significant correlations among BTEX. Calculated correlation coefficients of ambient air sampling sites were $0.61{\sim}0.954$ for commercial /residential area and $0.613{\sim}0.998$ for industrial area. However, they showed different correlation between commercial/residental area and industrial area. It implied that the emission sources were different from each area.