• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.53-59
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• 2011

The using of diesel engine will be increased in the world for fuel economy. But diesel engine emits harmful emissions such as much NOx, smoke etc. In this study, experiments were performed to investigate the spray characteristics of diesel spray in a common-rail system according to fuel temperature, injection pressure, injection period and fuel viscosity etc. using a high speed video camera. Diesel oil has different spray patten due to injection pressure and injection period in a common-rail system. A Filter pressure was influenced by fuel temperature which was turned to fuel viscosity related to a fluid flowing. The effect of the bio-diesel fuel mixing ratio on the spray and atomization characteristics was also investigated at various experimental conditions. It shows that the droplet atomization characteristics of bio-diesel fuel showed deteriorated results as the mixing ratio of biodiesel increased because of the high viscosity.

• Journal of the Korean Society of Combustion
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• v.20 no.2
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• pp.28-35
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• 2015

In this study, the CH4/air lean-rich combustion system with exhaust gas recirculation (EGR) was investigated to explore the potential for lowering pollutant emissions. To achieve this purpose, experiments of lean-rich combustion system with EGR were conducted to measure the changes in the characteristics of the pollutant emission and flame shape with various equivalence ratios and EGR rates. Here, this study was applied to the fuel distribution ratio of 3:1 for the formation of the lean and rich flames. Additionally, the results were compared with $CH_4$/air lean premixed combustion system. The results show that flame shape of lean-rich combustion system was determined by lean and rich equivalence ratios (${\Phi}_L$ and ${\Phi}_R$) and stratified flame was formed with increasing ${\Phi}_R$. According to the pollutant emission characteristics based on experimental results, the NOx and CO emission index (EINOx and EICO) decreased with increasing EGR rate. Especially, in the range needed to form a stable flame, the reduction rates of EINOx and EICO were approximately 47% and 48% for an EGR rate of 25%, global equivalence ratio of 0.85 and ${\Phi}_L$ of 0.80 compared with lean premixed combustion system (${\Phi}$ = 0.78).

• Environmental and Resource Economics Review
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• v.13 no.1
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• pp.133-160
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• 2004

This paper analyzes the long-run effects of an environmental tax levied on motor vehicles. If the government charges their consumers the tax as much as the monetary value of the external damage due to the pollutants emitted from motor vehicles, the operation of vehicles is reduced to the socially optimal level, alike to ordinary Pigouvian taxes. Thus, air pollution abatement is realized in the short run. Moreover, in the long run, the tax leads the consumers to prefer cleaner vehicles owing to the tax burden, and so the firms produce the motor vehicles with less pollutants emitted to meet the change of demand. Therefore, the tax has the additional effect on air pollution abatement. This result is obtained from the simulation in the oligopoly model which has an interior solution when the vehicles are horizontally and vertically differentiated.

• Journal of ILASS-Korea
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• v.21 no.2
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• pp.95-103
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• 2016

The effect of pilot injection quantity on the combustion and emissions characteristics of a compression ignition engine with a biodiesel-compressed natural gas (CNG) dual fuel combustion (DFC) system is studied in this work. Biodiesel is used as a pilot injection fuel to ignite the main fuel, CNG of DFC. The pilot injection quantity is controlled to investigate the characteristics of combustion and exhaust emissions in a single cylinder diesel engine. The injection pressure and injection timing of pilot fuel are maintained at approximately 120 MPa and BTDC 17 crank angle, respectively. Results show that the indicated mean effective pressure (IMEP) of biodiesel-CNG DFC mode is similar to that of diesel-CNG DFC mode at all load conditions. Combustion stability of biodiesel-CNG DFC mode decreased with increase of engine load, but no notable trend of cycle-to-cycle variations with increase of pilot injection quantity is discovered. The combustion of biodiesel-CNG begins at a retarded crank angle compared to that of diesel-CNG at low load, but it is advanced at high loads. Smoke and NOx of biodiesel-CNG are simultaneously increased with the increase of pilot fuel quantity. Compared to the diesel-CNG DFC, however, smoke and NOx emissions are slightly reduced over all operating conditions. Biodiesel-CNG DFC yields higher $CO_2$ emissions compared to diesel-CNG DFC over all engine conditions. CO and HC emissions for biodiesel-CNG DFC is decreased with the increase of pilot injection quantity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.281-284
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• 2011

Recently, many drivers was the damage caused by similar oil product sales and gas station by not using quantitative gas. so, these damages is expected to rise damages by increasing these problem. By using similar oil products, caused damage in the fuel lines' working of lubrication and self-cleaning function for the occurred trouble in the part of the early obsolescence and the accumulation of impurities in the fuel lines, combustion rate due to the difference between retail gasoline engine, the burden of weight, Toxic substances in exhaust emissions, engine oil and unresolved issue is the chemical reaction can occur. to prevent these damages, using the system use in-vehicle state data with OBD-II protocol and measure quantitative gas and similar oil. In this paper, there implement similar oil identification and quantitative gas system through OBD-II scanner to provide WiFi communcation by using WinCe development Board.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.133-140
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• 2016

Thermoelectric generator, which is known as using Seebeck effect, have been widely applied in many industrial parts, for instance, from submarine to equipments capable of producing hot or cooling water. Its usefulness was verified in terms of producing electric power using temperature difference and vice versa. Application on thermoelectric generator has been mainly forced on exhaust gas of automotive engine so far. In this study, the possibility was investigated whether electric power could be produced by using cooling water in automotive engine. As the result, it showed that electric power had differences depending on shapes of power auxiliary apparatus and, in this experiment, maximum of electric power was 1.5 voltage.

• Journal of Power System Engineering
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• v.19 no.3
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• pp.16-21
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• 2015

Nitrous oxide($N_2O$) concentration in the atmosphere has been constantly increased by the human activities with industrial growth after the industrial revolution. One of factors to increase $N_2O$ concentration in the atmosphere is the $N_2O$ emission caused by the combustion of marine fuel. Especially, a sulfur component included in marine fuel oils is known as increasing the $N_2O$ formation in diesel combustion. Form this point of view, $N_2O$ emission from a ship is not negligible. On the other hand, Exhaust gas recirculation(EGR) that have thermal, chemical and dilution effect is effective method for reducing the NOx emission. In this study, an author investigated $N_2O$ reduction by using EGR on a direct injection diesel engine. The test engine was a 4-stroke diesel engine with maximum output of 12 kW at 2600rpm, and operating condition of the engine was a fixed load of 75%. The experimental oil was a blend-fuel that were adjusted with sulfur ratio of 3.5%, and EGR ratio of 0%, 10%, 20% and 30%. In conclusion, diesel fuel that contained 3.5% sulfur component increased $SO_2$ emission in exhaust gas, and increment of EGR ratio reduced NO emission. Moreover, $N_2O$ emission was decreased as over 50% at EGR ratio of 10% and reduced 100% at EGR ratio of 30% compared with $N_2O$ emission of 0% EGR ratio.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.381-386
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• 2015

Environmental pollution and alternative energy has attracted increasing interest. The use of diesel engines is expected to increase in the world owing to their fuel economy. The problem of air pollution emissions from marine engines is causing a major concern in many areas. An alternative fuel was introduced as an environmentally friendly fuel to reduce the toxic emissions from conventional fossil fuels. Biodiesel fuel, which is a renewable energy is highlighted as environmentally friendly energy. This energy can be operated in regular diesel engines when it is blended with invariable ratios without making changes. In this study, a bio-diesel fuel was produced from waste cooking oil and applied to a marine diesel engine to examine the effects on the characteristics of combustion. Waste cooking oil contains a high cetane number and viscosity component, a low carbon and oxygen content. As a result, the brake specific fuel consumption was increased, and the cylinder pressure, rate pressure rise and rate of heat release were decreased.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.395-400
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• 2017

The paper discussed the air-to-fuel ratio control of automotive fuel-injection systems using the cerebellar model articulation controller(CMAC) neural network. Because of the internal combustion engines and fuel-injection's dynamics is extremely nonlinear, it leads to the discontinuous of the fuel-injection and the traditional method of control based on table look up has the question of control accuracy low. The advantages about CMAC neural network are distributed storage information, parallel processing information, self-organizing and self-educated function. The unique structure of CMAC neural network and the processing method lets it have extensive application. In addition, by analyzing the output characteristics of oxygen sensor, calculating the rate of fuel-injection to maintain the air-to-fuel ratio. The CMAC may easily compensate for time delay. Experimental results proved that the way is more good than traditional for petrol control and the CMAC fuel-injection controller can keep ideal mixing ratio (A/F) for engine at any working conditions. The performance of power and economy is evidently improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5980-5987
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• 2014

As a response to exhaust gas regulations, the electronic control system was applied to the diesel engine. The injected fuel mass and injection timing are accurately controlled using it, and the fuel efficiency and the engine output are significantly increased. In addition, the noise and the vibration of vehicles are decreased. To maintain the optimal performance of an electronic control diesel engine, it is important to control the fuel injection pressure accurately using the fuel pressure regulator. When the fuel pressure regulator is not worked normally, the failure phenomena (starting failure, staring delay, accelerated failure, engine mismatch et al.) occurred because the fuel pressure is not stabilized and controlled accurately. In this study, the effects on a fuel pressure, return fuel mass flow, and engine rotating speed according to the control rate of fuel pressure regulator were investigated to analyze the performance variation under the failure conditions of a fuel pressure regulator. As a result, when the control rate of a fuel pressure regulator decreased by 4%~6% compared to that of the standard condition, the variation of engine rotating speed and return fuel flow were increased greatly, and the abnormal condition occurred. In addition, it is possible to diagnose the failure of a fuel pressure regulator by monitoring these conditions.