• 한국자동차공학회논문집
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• 제11권2호
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• pp.104-110
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• 2003

As exhaust emission standards are more stringent, higher conversion efficiency of automotive catalytic converter is required. In addition, catalytic converter is deteriorated during mileage accumulation of vehicle. Therefore the specification of catalytic converter should be decided in consideration of emission standards and deterioration. Because the decision of the specification of catalytic converter is required at the beginning of vehicle development procedure, it is important and necessary to fix the target values of green vehicle exhaust emissions. To do this, a linear regression analysis was done with in-use exhaust emissions data of 5 different kinds of vehicle that received US94 emission standards certification, and data handling methods including some statistical estimation were proposed. As a result, the fixed target values of NMHC, CO, NOx of green vehicle against US94 emission standards were 0.079, 0.83, 0.116, respectively. And expected in-use deterioration factor of NMHC, CO, NOx were 1.75, 2.02, 1.38, respectively. And also it was blown that even if failure rate is 30% after 80,000km driven, it might be sufficiently safe from emission failure confirmatory test of Korea. It is hopeful to make a database of in-use emissions to increase the confidence in correctness of the calculated target values.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2940-2945
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• 2008

The scale of 2.4 MW MCFC was taken to construct a high-efficiency and economical power generation system without CO2 emission into the atmosphere for utilizing its exhaust gas. The conventional steam turbine power generation system (STGS) was evaluated and the net generated power (NGP) was estimated to be only 133 kW and the STGS is not economically feasible. A CO2-caputuring repowering system was proposed, where low temperature steam (LTS) produced at HRSG by using exhaust gas from MCFC is utilized as a main working fluid of a gas turbine, and the temperature of LTS was raised by combusting fuel in a combustor by using pure oxygen, not the air. It has been shown that NGP of the proposed system is 264 kW, and CO2 reduction amount is 608 t-CO2/y, compared to 306 t-CO2/y of STGS. The CO2 reduction cost was estimated to be negligible small, even when the costs of oxygen production and CO2 liquefaction facilities etc. were taken into account.

• 한국수소및신에너지학회논문집
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• 제14권2호
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• pp.138-145
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• 2003

There are high expectations for DME(Dimethyl Ether) as a new alternative fuel for diesel engine. Compared with the conventional diesel engine, nearly zero soot emission and high thermal efficiency have been reported from DME fuelled CI engines. However, higher NOx emission is one of the disadvantages from DME Engines. In the present study, cooled EGR(Exhaust Gas Recirculation) was applied to DME engine modified from conventional Dl diesel engine, and effects of EGR were examined under various EGR temperature. Finally, it was concluded that the cooled EGR is an effective solution to reduce NOx emission from DME engine.

• 한국가스학회지
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• 제19권6호
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• pp.110-115
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• 2015

본 논문에서는 현재 입자상물질 저감장치인 DPF의 문제를 해소하기 위하여 제안된 것으로서, 단일채널내의 배기가스 통로를 양방향 제어하여 연소시 발생되는 배기가스를 효율적으로 정화한다. 1개의 DPF장치를 장착하고 회전형 밸브를 교번제어 하여 DPF 내부에 입자상물질 적층현상으로 인한 배기가스의 내부압력 증가를 피할수 있고, 출력저하 및 연비효율이 떨어지는 등의 문제를 획기적으로 개선하여 고효율의 출력을 유도할 수 있는 입자상물질 정화시스템을 개발한다.

• 한국항해항만학회지
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• 제48권2호
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• pp.125-136
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• 2024

This research presents an innovative integrated ethanol solid oxide fuel cell (SOFC) system designed for applications in marine vessels. The system incorporates an exhaust gas heat recovery mechanism. The high-temperature exhaust gas produced by the SOFC is efficiently recovered through a sequential process involving a gas turbine (GT), a regenerative system, steam Rankine cycles, and a waste heat boiler (WHB). A comprehensive thermodynamic analysis of this integrated SOFC-GT-SRC-WHB system was performed. A simulation of this proposed system was conducted using Aspen Hysys V12.1, and a genetic algorithm was employed to optimize the system parameters. Thermodynamic equations based on the first and second laws of thermodynamics were utilized to assess the system's performance. Additionally, the exergy destruction within the crucial system components was examined. The system is projected to achieve an energy efficiency of 58.44% and an exergy efficiency of 29.43%. Notably, the integrated high-temperature exhaust gas recovery systems contribute significantly, generating 1129.1 kW, which accounts for 22.9% of the total power generated. Furthermore, the waste heat boiler was designed to produce 900.8 kg/h of superheated vapor at 170 ℃ and 405 kP a, serving various onboard ship purposes, such as heating fuel oil and accommodations for seafarers and equipment.

• 한국기계가공학회지
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• 제19권9호
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• pp.40-46
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• 2020

Inspection of vehicle systems is regularly performed by the state to ensure the emission status and the safety of vehicles. Thereby, the safety and quality of life can be improved by reducing green-house gases and fine dust, which are the main causes of vehicle defects and air pollution. This study analyzed the soot measuring probes used in the free acceleration mode method, at no-load condition, looking at the efficiency of a probe to measure soot emissions from diesel vehicles. In this study, a technique that can improve the inhalation efficiency of the probe over the (a) probes and the improved (b) probes was applied to probes (c). Probe (c) involves a structure designed close to the center of the circumference of the exhaust pipe. Results showed that the suction efficiency was improved by adding a variable center unit.

• 태양에너지
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• 제2권2호
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• pp.11-20
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• 1982

This paper presents the experimental investigations of a system as a second treatment means to increase boiler efficiency and heat transfer from combustion gas to heating surfaces in the case of spray combustion. In order to reburn residual combustible components accelerate the burning rate of sprayed fuel droplets, improve the diffusion flame and delay the residence time of the flame, advice with slit type nozzles for spouting preheated supplementary air is used in this study. In the experiment, boiler efficiency and smoke concentration in the exhaust gas at given conditions are measured in both case of installing and not-installing device in the model of combustion chamber which was designed to be equipped with five surfaces. The results obtained in this experiment are as follows ; 1. The optimum values of air rate ${\lambda}$ are about 1.3 in both case. 2. The exhaust gas temperature in the case with device increases about $30{\sim}70^{\circ}C$ above that of the case without the device. 3. Boiler efficiency and reduction effect of smoke emissions are improved considerably.

• 한국기계가공학회지
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• 제19권1호
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• pp.29-35
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• 2020

Car inspection systems are regularly carried out by the state to ensure the safety and emission status of cars, thereby improving the safety and quality of life by reducing fine dust and greenhouse gases that are the main culprits of vehicle defects and air pollution. These automobile inspections are largely divided into either regular or comprehensive inspections. This study analyzed the smoke measuring probes used in the lug - down 3 mode. In the previously issued paper "Improvement of Soot Probe Efficiency for Automotive Emission Measurement," an improved smoke measurement probe(B) improved on the problems that arise from the current smoke measurement probe (A). In this study, a technique that can improve the probe's inhalation efficiency over the improved (B) probes was applied to probes (C). Probe (C) involves a structure designed close to the center of the circumference of the exhaust pipe, and the suction efficiency was improved by adding a variable center unit.

• 동력기계공학회지
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• 제6권2호
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• pp.18-23
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• 2002

Recently, as people pay attention to the environmental pollution, the emission of diesel engine has become a serious problem. Diesel Oxidation Catalysts(DOC) were experimentally investigated for the purification of pollutants exhaust emission from the diesel engine. In this study, the conversion efficiency of exhaust gas was investigated with various washcoat materials of the DOC. It was formed that CO conversion efficiency depended on temperature, but THC conversion was dominated by temperature and space velocity. Conversion efficiency of THC and CO increased with the addition of ZSM-5 in the washcoat, whereas these conversion efficiency decreased by adding Nd and Ba additives. $V_2O_5$ additive had the thermal stability for high temperature. Thermal durability of the catalyst was improved as increase of $V_2O_5$ additive.

• Journal of Biosystems Engineering
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• 제22권2호
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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.