• Journal of the Korean Society of Combustion
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• v.15 no.4
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• pp.53-57
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• 2010

The purpose of the present work is to investigate the effect of gasoline-premixing on a combustion and emissions characteristics in a compression ignition engine. For studying combustion characteristics, a combustion pressure and rate of heat release (ROHR) were measured using a single-cylinder DI compression ignition engine with a common-rail injection system and premixed fuel injection system. In addition, exhaust emissions characteristics were studied using emission analyzers and smoke meter. The experimental results showed that the case of gasoline-premixing had longer ignition delay and lower combustion pressure compared to the cases of diesel direct injection. Furthermore, premixed gasoline-air mixture reduced NOx emissions due to low peak of ROHR.

• The Journal of Internal Korean Medicine
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• v.39 no.6
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• pp.1150-1167
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• 2018

Objective: The purpose of this study was to investigate the effect reducing blood pressure (BP) using Xuefuzhuyu Decoction (XFZYD) in adults with essential hypertension (EH). Method: Search engine, such as PubMed, EMBASE, Cochrane library, Web of Science, J-STAGE, CiNii, CNKI, OASIS, NDSL, KISS, RISS, and DBpia, were used. The search period was from the beginning of the search engine to June 30, 2018 and there were no limits regarding languages. The selection and extraction of literatures were performed independently by two authors. Meta-analysis was done on the total effective rate (TER), Systolic BP (SBP) and Diastolic BP (DBP). Cochrane's risk of bias (ROB) was used as the methodological quality assessment scale. Results: Twenty studies were finally selected. We observed that a combination treatment using XFZYD and an antihypertensive drug (AHD) was 5.1 times more effective in lowering BP than using AHD alone on TER. The mean differences in SBP and DBP were -10.65 mmHg (95% Confidential Interval (CI) -13.55 mmHg, -7.74 mmHg, P<0.00001), -5.92 mmHg (95% CI -7.14, -4.38, P<0.00001), respectively. Conclusion: A combination treatment using XFZYD and AHD may be more effective in reducing BP than using AHD alone. Because of the poor methodological quality of the studies conducted thus far, high-quality clinical trials will be required in the future.

• Journal of the Korean Society of Combustion
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• v.16 no.3
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• pp.52-58
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• 2011

The purpose of this paper is to investigate the effect of equivalence ratio on the combustion and emission characteristics of a compression ignition engine fueled with biodiesel. In this research, a single-cylinder direct injection engine with 373.3 cc of displacement volume was tested on DC dynamometer. In order to investigate the effect of biodiesel equivalence ratio on combustion characteristics, the experiments were conducted at various equivalence ratios and injection pressures of 40~120 MPa. For investigating engine performance, lambda meter was connected and equivalence ratios was varied from 0.6 to 1.0. In addition, the exhaust emissions such as oxides of nitrogen($NO_X$), hydrocarbon(HC) and carbon monoxide(CO) were measured by exhaust gas analyzer under the various air/fuel ratios. The experimental results show that maximum IMEP was measured at the 0.8 of equivalence ratio. Furthermore, $NO_X$ emission was rapidly decreased as the increase of equivalence ratio. However soot emission was significantly increased according to the increase of equivalence ratio.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.4 s.316
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• pp.10-20
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• 2007

In this paper, we propose the reference implementation of WIPI runtime engine supporting various platforms such as REX OS, Qplus and Windows. We describe the architecture of WIPI runtime engine according to each platform, and introduce the method for avoiding repetitive develoment. And we explain the implementation of a linker and a loader on REX OS and describe the runtime engine structure on Qplus, a kind of embedded linux. And we introduce the implementation of the Jlet/MIDlet emulator based on a Java virtual machine and the Clet emulator based on Windows. Finally we verify the interoperability and the perfection of the proposed reference implementation through the result of the HCT and the PCT and the normal operation of the example programs.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3026-3031
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• 2008

In conventional closed-loop crankcase ventilation systems, the lubrication oil had to be re-circulated to the intake manifold, in the form of oil mist mixed with the blow-by gas. This blow-by gas containing the engine lubricant oil affects on the engine problems and the exhaust emissions. A high-efficient oil separator is required to minimize consumption of engine oil and reduce harmful emissions. In the conventional oil separator of CI engines, it has good oil separation performance even though separator design is simple, due to lots of the blow-by gas. As the emission regulation becomes severe, the oil separator for SI engines is also required. But in SI engines, separator design should be optimized, due to small size of oil particles and little amount of blow-by gas. In this study, oil separation performance classified by diameter of oil mist in cylinder head cover internal model which has three cyclones and two baffle plates for SI engine is calculated with CFD methodology.

• Journal of Magnetics
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• v.21 no.4
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• pp.537-543
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• 2016

Currently, an interest in electric vehicles (EVs) exhibited by automakers, government agencies and customers make it as more attractive research. This is due to carbon dioxide emitted by conventional combustion engine that worsens the greenhouse effect nowadays. Since electric motors are the core of EVs, it is a pressing need for researchers to develop advanced electric motors. As one of the candidates, switched flux machine (SFM) is initiated in order to cope with the requirement. This paper proposes a new alternate circumferential and radial flux (AlCiRaF) of permanent magnet switched flux machines (PMSFM) for light weight electric vehicles. Firstly, AlCiRaF PMSFM is compared with the conventional PMSFM based on some design restrictions and specifications. Then the design refinements techniques are conducted by using deterministic optimization method in order to improve preliminary performance of machine. Finally the optimized machine design has achieved maximum torque and power of 47.43 Nm and 12.85 kW, respectively, slightly better than that of conventional PMSFM.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.6
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• pp.729-735
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• 2007

AC cold arc welding process with AWS E Ni-CI and NiFe-CI is sometimes used to repair damaged cast iron parts in diesel engine room. But if some difference in hardness on welding zones, repaired parts would be cracked in a short. To overcome this default. this study is performed on varying preheating temperature of welding parts, selecting welding rod etc. Experimental results showed that difference in hardness on welding zones at $200^{\circ}C$ was less than $100^{\circ}C$ and less low current than high current. From this study we could conclude that repair welding at $200^{\circ}C$ preheating and low current as possible as welding in damaged cast iron parts was a little difference in hardness on welding zones.

• Journal of Energy Engineering
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• v.25 no.2
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• pp.29-36
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• 2016

In this study, diesel/natural gas dual-fuel engine was studied numerically using DoE method. The engine is CI engine for power generation and modelled by 1-D simulation GT-power. The combustion and emission characteristics were analyzed as a function of IVO, IVC and the ratio of natural gas to total fuel enegy. As the proportion of natural gas increases, the BSFC(Brake specific fuel consumption) is increased and BSNOx(Brake specific NOx) is decreased. If specific valve timing to improve the BSFC is applied to the engine, the BSFC is decreased by 1% and simultaneously BSNOx is decreased by 36%.

• Journal of ILASS-Korea
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• v.24 no.1
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• pp.35-42
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• 2019

Syngas is widely produced by incomplete combustion of coal, water vapor, and air (oxygen) in a high-temperature/high-pressure gasifier through a coal-gasification process for power generation. In this study, a simulation syngas which was mainly composed of $H_2$, CO, $CO_2$, and $N_2$ was fueled with diesel. A modified single cylinder compression ignition (CI) engine is equipped with intake port syngas supply system and mechanical diesel direct injection system for dual fuel combustion. Combustion and emission characteristics of the engine were investigated by applying various syngas composition ratios and compression ratios. Diesel fuel injection timing was optimized to increase indicated thermal efficiency (ITE) at the engine speed 1,800 rpm and part load net indicated mean effective pressure ($IMEP_{net}$) 2 to 5 bar. ITE of the engine increased with the $H_2$ concentration, compression ratio and engine load. With 45% of $H_2$ concentration, compression ratio 17.1 and $IMEP_{net}$ 5 bar, ITE of 41.5% was achieved, which is equivalent to that of only diesel fuel operation.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.2
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• pp.1-8
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• 2004

In this paper, we implement the Digital Signal Processing System based on Human Machine Interface technology for the telematics with embedded noise-robust speech recognition engine and develop the communication system which can be applied to the automobile information center through the human-machine interface technology. Through the embedded speech recognition engine, we can develop the total DSP system based on Human Machine Interface for the telematics in order to test the total system and also the total telematics services.