• Journal of Advanced Marine Engineering and Technology
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• v.27 no.7
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• pp.839-844
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• 2003

As sea water is being used as only heat source of LNG open rack vaporizer, serious problem has been risen in LNG terminal by the lack of heating energy source for LNG vaporization due to the temperature drop of sea water in winter. In this paper the new double-tube triple-flow(TRIDEX) vaporizer was suggested to solve the problem and the system was thermally analysed. LPG(liquefied petroleum gas) and sea water were introduced as the heat sources for LNG TRIDEX vaporizer. The flow patterns of TRIDEX vaporizer are as follows: LNG flow in the annular space, PG(petroleum gas) flow in the inner tube, and sea water flow in the outside of the double pipe. The overall LNG vaporization system was consisted of TRIDEX vaporizer, LPG vaporizer and PG heater. LPG in TRIDEX was directly dispersed in the sea water desalination unit, so that LPG turns to be gas phase for the reuse in TRIDEX vaporizer. New TRIDEX vaporizer system for LNG evaporation was analysed as much more effective than the present single tube one in the case of colder temperature of sea water in winter.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.54-62
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• 2007

The knock characteristics in an engine were investigated under homogeneous charge compression ignition (HCCI) operation. Liquefied petroleum gas (LPG)and gasoline were used as fuels and injected at the intake port using port fuel injection equipment. Di-methyl ether (DME) was used as an ignition promoter and was injected directly into the cylinder near compression top dead center (TDC). A commercial variable valve timing device was used to control the volumetric efficiency and the amount of internal residual gas. Different intake valve timingsand fuel injection amounts were tested to verify the knock characteristics of the HCCI engine. The ringing intensity (RI) was used to define the intensity of knock according to the operating conditions. The RI of the LPG HCCI engine was lower than that of the gasoline HCCI engine at every experimental condition. The indicated mean effective pressure (IMEP) dropped when the RI was over 0.5 MW/m2and the maximum combustion pressure was over 6.5MPa. There was no significant relationship between RI and fuel type. The RI can be predicted by the crank angle degree (CAD) at 50 CA. Carbon monoxide (CO) and hydrocarbon (HC) emissions were minimized at high RI conditions. The shortest burn duration under low RI was effective in achieving low HC and CO emissions.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.4
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• pp.809-816
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• 2001

This is a fundamental study to improve the performance of the LPG engine. The result were summarized as followed. 1. The measured torque and power on the fuel of LPG were indicated about 8% lower than those on gasoline with the same compression ratio. 2. In the case of LPG, BSFD at compression ratio of 9.7 was about 5% lower than that of 8.3 at 3,000ppm 3. HC and CO concentrations of the LPG were lower about 53%, 35% than those of gasoline

• Journal of Biosystems Engineering
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• v.22 no.2
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• pp.189-198
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• 1997

In order to find out the potential of LP gas as a substitute fuel for small fm engine, experiments were carried out with a four-stroke spark-ignition engine which was modified from a kerosene engine mounted on the power tiller. Performance characteristics of kerosene and LP gas engine such as torque, volumetric efficiency fuel consumption rate, brake thermal efficiency, exhaust temperature, and carbon monoxide and hydrocarbon emissions were measured and analyzed under various levels of engine speed and compression ratio. The results were summarized as follows. 1. It showed that forque of LPG engine was 41% lower than that of kerosene engine with the same compression ratio, but LPG engine with compression ratio of 8.5 it was showed similar torque level to kerosene engine with compression ratio of 4.5. 2. Fuel consumption of LPG engine was reduced by about 5.1% and thermal efficiency was improved by about 2% compared with kerosene engine with the same compression ratio. With the incrasing of compression ratio in LPG engine fuel consumption rate decreased and thermal efficiency increased. 3. Exhaust temperature of LPG engine was about 15% lower than that of kerosene engine. Concenrations of emissions from LPG engine was affected insignificantly by compression ratios, and carbon monoxide emissions from the LPG engine was not affected by engine speed so much. The carbon monoxide and hydrocarbon emissions from LPG engine were about 94% and 66% lower than those of kerosene engine, respectively.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.68.3-68
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• 2002

This paper presents a neural network approach to control exhaust gas recirculation(EGR) in a Liquefied Petroleum Gas(LPG) engine. In order to meet Increasingly stringent automotive exhaust emission regulations, alternative fuels such as LPG engines have been developed in many countries. HC&CO emissions of LPG engines can be easily reduced through air-fuel ratio control, but the control effect on NOx reduction is not good enough. Consequently EGR system is introduced to achieve a significant reduction in NOx emissions. Conventional EGR control uses the mapping method. The calibration time is long and the work is complex when adopting this mapping method. However neural networks are suitable f...

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.29-34
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• 2007

In recent years, the need for more fuel-efficient and lower-emission vehicles has driven the technical development of alternative fuels such as LPG(Liquefied Petroleum Gas) which is able to meet the limits of better emission levels without many modifications to current engine design. LPG has a hish vapor pressure and lower viscosity and surface tension than diesel and gasoline fuels. These different fuel characteristics make it difficult to directly apply the conventional gasoline or diesel fuel pump. In this study, experiments are performed to get performance and efficiency of the fuel pump under different condition of the temperature, rotating speeds, and composition of fuel. The characteristics of fuel pump were affected by cavitation occurred from the variation of temperature and composition.

• Journal of information and communication convergence engineering
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• v.4 no.1
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• pp.18-22
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• 2006

A small-sized gas identification system has been fabricated and characterized using an integrated gas sensor array and artificial neural-network. The sensor array consists of four thick-film oxide semiconductor gas sensors whose sensing layers are $In_{2}O_{3}-Sb_{2}O_{5}-Pd-doped\;SnO_2$ + Pd-coated layer, $La_{2}O_{5}-PdCl_{2}-doped\;SnO_2,\;WO_{3}-doped\;SnO_{2}$ + Pt-coated layer and $ThO_{2}-V_{2}O_{5}-PdCl_{2}\;doped\;SnO_{2}$. The small-sized gas identification instrument is composed of a GMS 81504 containing an internal ROM (4k bytes), a RAM (128 bytes) and four-channel AD converter as MPU, LEDs for displaying alarm conditions for three gases (liquefied petroleum gas: LPG, liquefied natural gas: LNG and carbon monoxide: CO) and interface circuits for them. The instrument has been used to identify alarm conditions for three gases among the real circumstances and the identification has been successfully demonstrated.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.23-28
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• 2002

As the interest on the air pollution is gradually rising up at home and abroad, automotive industries have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative aftertreatment systems, and using clean fuels. Methanol, ethanol, LNG, LPG, H2, reformulated gasoline are generally recognized as the clean fuel. Since the low price policy of government on LPG has expanded its vehicle market recently, there is concern of the exhaust emission of LPG vehicle. In this paper, we studied the value of LPG fuel as a clean fuel by comparing the results of the exhaust emission from LPG and Gasoline fueled vehicles, and discussed its limitation of LPG vehicle with mixer type as a fuel supply system. FTIR was used to understand the difference of exhaust emission components of LPG and Gasoline fueled vehicles.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.49-56
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• 2021

Liquefied Petroleum Gas is divided into liquefied gases containing propane (C₃H₈) and butane (C₄H₁₀). The quality of LPG varies greatly depending on the composition of the mixture, so it is important to measure the composition accurately. It is difficult to determine the composition of the mixture because liquid and gas coexist at room temperature. Therefore, the uncertainty in determining the concentration of hydrocarbons by component is high, and there are many problems that differ from the actual content standard. Therefore, it is necessary to develop a mixed liquid propane standard gas for the composition and accurate concentration of hydrocarbon substances. Mixed liquid propane standard gas is manufactured into bellows-type constant-pressure cylinders by ISO-6142 (2015). The homogeneity of the four standard gases manufactured was confirmed to be GC-FID. The manufacturer's uncertainty of expansion was 0.01 % to 0.30 % and homogeneity was 0.03 % to 0.25 %. In this mixed liquid propane standard gas, the relative expansion uncertainty of weight method, manufacturing consistency, cylinder adsorption and long-term stability was developed within 0.26 %-1.3 9% (95% of confidence level, k=2).

• Journal of the Korean Institute of Gas
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• v.19 no.1
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• pp.18-22
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• 2015

This paper presents the stress strength safety of LPG steel cylinder for various corner radiuses of upper round end plate and lower round end plate by using a finite element method. The FEM analyzed results indicate that the most influential elements is a corner radius of upper round end plate and lower round end plate rather than a thickness of LPG cylinder. But, the thickness of a steel cylinder is an important design element considering for a weight reduction of a cylinder. Thus, this paper recommends that the LPG steel cylinder thickness is 2.3~2.6mm and the corner radius of upper round end plate and lower round end plate is over 157mm as an optimum design for the maximum testing pressure of 3.04MPa.