• 한국자동차공학회논문집
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• 제8권4호
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• pp.51-58
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• 2000

It is well known that the majority of the emissions measured from vehicle exhaust in the US Federal Test Procedure(FTP-75) are emitted during the first 60 seconds. This paper describes an experimental study on SI engine emissions reduction after cold start with interval secondary air injection and coolant control. Secondary air injection after cold start to reduce exhaust emissions causes an exothermic reaction at the exhaust port and gives sufficient air to the catalyst. For that reason engine-out emissions oxidized in the exhaust port and the rapid heating of a catalytic converter after cold start with CSAI and ISAI are estimated. The influence of the coolant temperature on SI engine emissions has been estimated. In the present studycoolant control of the cylinder head tempeature is used to investigate the effect of coolant temperature on SI engine emissions. The results show that engine-out hydrocarbon and carbon monoxide emissions are considerably reduced with interval secondary air injection and coolant control.

• Journal of Advanced Marine Engineering and Technology
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• 제25권3호
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• pp.471-486
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• 2001

The principal trends in the course of emission control legislation are reviewed in this paper. In order to keep such a regulation, moreover, an inquiry ito the concrete technical possibility is conducted through review articles, Also, the composition of exhaust gases emitted from a marine diesel engine are investigated as several samples and the measures that can satisfy the value of regulation are handled with laying stress on the control methods discussed to date. It was concluded that various combined systems can be made to reduce NOx emissions without deteriorating substantially navigation costs since many technologies for reducing NOx emissions are being developed. All heat engines suffer from SOx emissions. There are two methods for reducing SOx emissions: desulfurization from exhaust gas and removal of sulfur composition from fuel oil. However it is necessary to watch the development of these technologies to evaluate which method is more favorable. Heat engines have a big problem in the regulation of environmental pollution from exhaust emissions. In the near future, however, diesel engines may be superior to other heat engines, owing to the high thermal efficiency, although the sales of individual models in dises engines may be prosperous and declining.

• 한국대기환경학회지
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• 제34권1호
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• pp.87-100
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• 2018

Fast economic growth and urbanization of China have been causing air pollution not only over its domestic but transboundary atmosphere. Recent high fine particle pollution episodes in China made the government move toward more stringent air pollution control policies - which are mostly fuel switching and emissions control. In this research, we tried to understand characteristics of Chinese emissions and their change by analyzing its emissions inventory by year, sector, and region. From the inter-comparison of existing bottom-up emission inventories, we found relatively good agreements (<20% difference) for $SO_2$ and $NO_x$, but 30% or more discrepancies for some pollutants. Inter-comparison with top-down $NO_x$ emissions estimates also showed 20~50% differences by year. The regional distribution and inter-annual changes of emissions revealed different stages of energy/fuel mix and policy penetration. Early increase of pollutants emissions in the eastern part of China might give strong influences to the Korean peninsular in early 2000s but, more stringent control in that region would help improving air pollution in Korea in near future.

• International Journal of Automotive Technology
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• 제7권7호
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• pp.763-768
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• 2006

Emission reduction in the cold start period of SI engines is crucial to meet stringent emission regulations such as SULEV Emissoin reduction is the starting point of the study in the which the variable valve timing (VVT) technology may be one promising method to minimize cold start emissions while maintaining engine performance. This is because it is possible to change valve overlap and residual gas fraction during cold start and idle operations. Our previous study showed that spark timing is another important factor for reducing cold-start emissions since it affects warm-up time of close-coupled catalysts (CCC) by changing exhaust gas temperature. However, even though these factors may be favorable for reduction of emissions, they may deteriorate combustion stability in these operating conditions. This means that the two variables should be optimized for best exhaust emissions and engine stability. This study investigated the effects of valve and spark timings in idle performance such as combustion stability and exhaust emissions. Experiments showed that valve timings significantly affected engine stability and exhaust emissions, especially CO and $NO_x$, due to change in residual gas fraction within the combustion chamber. Spark timing also affects HC emissions and exhaust gas temperature. Yet it has no significant effects on combustion stability. A control strategy of proper valve timing and spark timing is suggested in order to achieve a reduction in exhaust emissions and a stable operation of the engine in a cold start and idle operation.

• Journal of Mechanical Science and Technology
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• 제15권11호
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• pp.1588-1598
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• 2001

The effects of recirculated exhaust gas on the characteristics of NOx and soot emissions under a wide range of engine loads were experimentally investigated by using a four-cycle, four-cylinder, sw irl chamber type, water-cooled diesel engine operating at three engine speeds. The purpose of this study was to develop the EGR-control system for reducing NOx and soot emissions simultaneously in diesel engines. The EGR system is used to reduce NOx emissions, and a novel diesel soot removal device with a cylinder-type scrubber for the experiment system was specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The experiments were performed at the fixed fuel injection timing of 4$^{\circ}$ ATDC regardless of experimental conditions. It was found that soot emissions in exhaust gases were reduced by 20 to 70% when the scrubber was applied in the range of the experimental conditions, and that NOx emissions decreased markedly, especially at higher loads, while soot emissions increased owing to the decrease in intake and exhaust oxygen concentrations, and the increase in equivalence ratio as the EGR rate is elevated.

• 한국기후변화학회지
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• 제6권4호
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• pp.367-377
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• 2015

This study analyzed the effectiveness of China's policy to reduce of sulfur dioxide. China's $12^{th}$ Five-year plan on national economic and social development emphasized environmental protection and low-carbon economic development. Sulfur dioxide was one of the major gases to affect air pollution and climate change and its control became a key policy agenda in the environment and energy sector. As the absolute amount of sulfur dioxide emissions in China came from the industrial sector, the control of the coal-based energy was especially urgent. This study analyzed the factors that influenced the sulfur dioxide emissions and the policy effects to reduce sulfur dioxide in China from 2003 to 2012 based on regional data. The air pollution treatment investments showed the biggest impact together with energy conservation policy in reducing sulfur dioxide emissions. However, pollutant emissions charge did not show a relevant policy effectiveness in all regions as the amount of charge would be smaller than economic benefit from non-compliance. Rationalizing pollutant emissions charge is, therefore, a key policy task for further reduction of sulfur dioxide emissions.

• 한국자동차공학회논문집
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• 제23권6호
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• pp.623-632
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• 2015

This study proposes a control strategy of the common rail pressure with a fuel injection limitation algorithm to reduce particulate matter (PM) emissions under transient states. The proposed control strategy consists of two parts: injection quantity limitation and rail pressure adaptation. The injection limitation algorithm determines the maximum allowable fuel injection quantity to avoid rich combustion under transient states. The fuel injection quantity is limited by predicting the burned gas rate after combustion; however, the reduced injection quantity leads to deterioration of engine torque. The common rail pressure adaptation strategy is designed to compensate for the reduced engine torque. An increase of the rail pressure under transient states contributes to enhancement of the engine torque as well as reduction of PM emissions by promoting atomization of the injected fuel. The proposed control strategy is validated through engine experiments. The rail pressure adaptation reduced the PM emission by 5-10% and enhanced the engine torque up to 2.5%.

• Asian Journal of Atmospheric Environment
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• 제12권1호
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• pp.37-46
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• 2018

The Minamata Convention on Mercury entered into force on August 16, 2017. It requires Parties to the Convention to control and, where feasible, reduce mercury emissions from the listed sources. To implement the Convention, Japan amended the Air Pollution Control Law and added clauses that force operators to control their mercury emissions below emission limit values (ELVs). The ELVs have been established separately for new and existing sources, targeting the source categories listed in the Convention: coal-fired boilers, smelting and roasting processes used in the production of non-ferrous metals (lead, zinc, copper and industrial gold), waste incineration facilities and cement clinker production facilities. The factors used to establish the ELVs include the present state of mercury emissions from the targeted categories as well as the mercury content in fuels and materials, best available techniques (BATs) and best environmental practices (BEPs) to control and reduce mercury emissions and ELVs or equivalent standards to control mercury emissions in other countries. In this regard, extensive data on mercury emissions from flue gas and the mercury content of fuels and materials were collected and analyzed. The established ELVs range from $8{\mu}g/Nm^3$ for new coal-fired boilers to $400{\mu}g/Nm^3$ for existing secondary smelting processes used in the production of copper, lead and zinc. This paper illustrates the ELVs for the targeted source categories, explaining the rationales and approaches used to set the values. The amended Law is to be enforced on April 1, 2018. From future perspectives, checks of the material flow of mercury, following up on the state of compliance, review of the ELVs and of the measurement and monitoring methods have been noted as important issues.

• Journal of Korean Society for Atmospheric Environment
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• 제15권E호
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• pp.29-38
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• 1999

This study identified emission sources and emissions of air pollutants such as volatile organic compounds (VOCs), solvents, and acid gases produced from chemical plants. We collected air samples from various processes, reactors and facilities using VOC detectors and workers' experience. We identified chemical structures and emission concentrations of air pollutants. We analyzed total emissions of air pollutants emitted from the chemical plants. Also, we developed some emission reduction technologies based on chemical types and emission situations of the identified air pollutants. For reduction of air emissions of acid gases, we employed a method improving solubility of pollutants by reducing scrubber operation temperature, increasing surface area for effective contact of gas and liquid, and modifying or changing chemicals used in the acid scrubbers. In order to reduce air emissions of both amines and acid gases, which have had different emission sources each other but treated by one scrubber, we first could separate gas components. And then different control techniques based on components of pollutants were applied to the emission sources. That is, we first applied condensation and then acid scrubbing method using H2SO4 solution for amine treatment. However, we only used an acid scrubbing method using H2O and NaOH solution for acid gas treatment. In order to reduce air emissions of solvents such as dimethylformamide and toluene, we applied condensation and activated carbon adsorption. In order to reduce air emissions of mixture gases containing acid gases and slovents, which could not be separated in the processes, we employed a combination of various air pollution control devices. That is, the mixture gases were passed into the first condenser, the acid scrubber, the second condenser, and the activated carbon adsorption tower in sequence. In addition, for improvement of condensation efficiency of VOCs, we changed the type of the condensers attached in the reactors as a control device modification. Finally, we could successfully reduce air emissions of pollutants produced from various chenmical processes or facilities by use of proper control methods according to the types and specific emission situations of pollutants.

• 에너지공학
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• 제13권2호
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• pp.161-165
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• 2004

Evaporative emissions from gasoline powered vehicles continue to be a major concern. The performance of carbon canister in evaporative emission control systems has become an important aspect of overall fuel system development and design. A vehicle's evaporative emission control system is continuously working, even when the vehicle is not running, due to generation of vapors from the fuel tank during ambient temperature variations. In this study, the effects of evaporative emissions on the engine performance were investigated. The experimental results show the effectiveness of this system for future exhaust emissions and enhanced evaporative emissions. This paper discusses the evaluation on the relationship between carbon canister condition and engine performance while engine is running.