• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.33-39
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• 2019

The improvement of emissions, fuel economy, and combustion noise is a primary target in the development of heavy-duty diesel engines. Multiple injection has been introduced as one of the most promising strategies for this goal. In this research, various multiple injection methods were applied to achieve the optimal strategy in terms of emissions, fuel economy, and combustion noise. In the case of one pilot injection, the smoke emission deteriorated, while the NOx emission was reduced. In the case of 2 pilot injections, the NOx and smoke emissions were reduced by 73% and 84%, respectively. In this case, the combustion noise was analyzed with the maximum pressure-rise rate, and the fuel economy was evaluated with the help of the indicated specific fuel consumption. A 15%:15% 2-pilot injection strategy accomplished improvements of 32.9% for NOx, 60.4% for smoke, 1.95% for fuel consumption, and 19.4% for combustion noise compared to the case of single injection. Based on the data, an optimal injection strategy will be developed for a greater operating range in future work.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.E2
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• pp.57-65
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• 2007

In Korea, there is a general lack of information available on air emissions from industry. The reasons for this include the lack of regulatory requirements for emission monitoring, limited information on specific industries, and difficulties in monitoring certain sources. This paper presents the first detailed air pollutant emission factors from composite wood product manufacturing in Korea. This study introduced emission factors for wood-based panels such as plywood, particle board (PB), and medium density fiberboard (MDF). The emission factors of particulate matters (PM) and hazardous air pollutants (HAPs) from MDF were higher than that from other wood products. The concentration of total volatile organic compounds (TVOCs) for hot press from wood-based panels was higher than drying or gluing processes. Emissions data from NPIP were compared to the data from the suggested emission factors in this study and the US EPA's. The data from our emission factors were closer to the observed results than the data using the US EPA's emission factor.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.363-379
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• 2014

In an effort to cope with recent high oil price and global warming, developments of air lubricated ships have been pursued to reduce greenhouse gas emissions and to save fuel costs by reducing the frictional resistance. In this study, reduction in the frictional resistance by air lubrication with air layers generated on the lower surface of a flat plate was investigated experimentally in the large water tunnel of SSMB. The generated air layers were observed, and changes in the local frictional drag were measured at various flow rates of injected air. The results indicated that air lubrication with air layers might be useful in reducing the frictional resistance at specific conditions of air injection. Accordingly, resistance and self-propulsion tests for a 66K DWT bulk carrier were carried out in the towing tank of SSMB to estimate the expected net power savings.

• Journal of Environmental Impact Assessment
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• v.17 no.5
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• pp.321-330
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• 2008

Methane is a potent greenhouse gas and methane emissions from landfills have been linked to global warming. In this study, LandGEM (Landfill Gas Emission Model) was applied to predict landfill gas quantity over time, and then this result was compared with the data surveyed on the site, Cheongju Megalo Landfill. LandGEM allows the input of site-specific values for methane generation rate (k) and potential methane generation capacity $L_o$, but in this study, k value of 0.05/yr and $L_o$ value of $170m^3/Mg$ were considered to be most appropriate for reflecting non-arid temperate region conventional landfilling, Cheongju Megalo Landfill. High discrepancies between the surveyed data and the predicted data about landfill gas seems to be derived from insufficient compaction of daily soil-cover, inefficient recovery of landfill gas and banning of direct landfilling of food garbage waste in 2005. This study can be used for dissemination of information and increasing awareness about the benefits of recovering and utilizing LFG (landfill gas) and mitigating greenhouse gas emissions.

• Journal of Environmental Policy
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• v.5 no.1
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• pp.1-23
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• 2006

This study explores what potential future greenhouse gas allocation schemes might mean for OECD countries, and discusses a number of concepts of equity, examines three specific burden sharing rules and formulae. The results indicate that Korea reduces its emission from 8.1% and 19.8% which is 34.9-85.8 million tons of $CO_2$ emission on the assumption that the overall level of abatement remains 20% of total 2000 OECD emissions.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1298-1307
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• 2001

Recently, the efforts to improve fuel economy and to reduce pollutant emission have become the main subject in the development of a gasoline engine. A lean combustion engine admitted as the best alternative is relatively lower fuel consumption rate and exhaust emissions. In this study, it is focused on intensifying intake flow field as one of methods to improve the performance of the lean combustion. First, three different types of suitable swirl control valve(SC7) with high swirl and tumble ratio are selected through steady flow experiment, being installed in a spark ignition engine. The relationship between lean misfire limit and torque was investigated with injection timing and spark ignition timing. Also, the effect of intensified swirl new on the combustion Stability and exhaust emissions was experimently examined by the measuring in-cylinder pressure and combustion variation. The results show that the engine with swirl control calve is superior to other conventional engine on the lean misfire limit, specific torque, combustion variation and emission, and the appropriate injection timing and spark ignition timing exist according to the type of swirl control valve.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.2
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• pp.57-62
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• 2000

The effect of exhaust gas recirculation(EGR) on the characteristics of exhaust gas emissions, and SFC are experimentally investigated by four-cylinder, four-cycle and direct injection marine diesel engine. In order to reduce the soot contents in the recirculated exhaust gas to intake system of the engines, a soot removal system of a cylinderical-type scrubber is specially designed and manufactured for the experimental system. (1) SFC is increased in downward convex curve style with increasing excess air ratio, it is increased with increasing EGR rate at the same excess air ratio. (2) NOx emission is reduced in downward convex curve style with increasing excess air ratio, it is reduced with increasing EGR rate at the same excess air ratio. (3) Soot emission is decreased in downward convex curve style with increasing excess air ratio, it is reduced with increasing EGR rate at the same excess air ratio. (4) CO emission is increased in nearly straight line style with increasing excess air ratio, it is increased with increasing EGR rate at the same excess air ratio. (5) HC emission is not constant tendency with increasing excess air ratio, it is increased with increasing EGR rate at the same excess air ratio.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.108-121
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• 1998

Using gas chromatography, the light hydrocarbon emissions were analyzed from SI engine fueled with methane and liquified petroleum gas(LPG), and the effects of fuel and engine operating condition were discussed. For this purpose, 14 species of light hydrocarbon including 1, 3-butadiene were separated, calibrated with standard gas, and measured from undiluted emissions. The brake specific hydrocarbon emission(BSHC) and ozone forming potential(BSO)3 were calculated and discussed with the changes of fuel, engine speed, load, fuel/air equivalence ratio, coolant temperature, and spark timing. As a result, exhaust emission was composed of mainly fuel composed of mainly fuel comp- onent and other olefin components of similar carbon number. The olefin components such as ethylene and propylene determine most of the ozone forming potential. The fraction of fuel component in total hydrocarbon emission was bigger with methane fuel than with LPG fuel. Also fuel fraction increased at high speed or high speed or high temperature of exhaust gas, and to lesser extent with high coolant temperature and retarded spark. However, the effect of equivalence ratio had different tendency according to fuels.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.336-343
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• 2017

Intake air conditions, such as air temperature, pressure, and humidity, are very important parameters that influence engine performance including combustion and emissions characteristics. The purpose of this study is to investigate the effects of intake air temperature on combustion and exhaust emissions characteristics in a single cylinder diesel engine. In this experiment, an air cooler and a heater were installed on the intake air line and a gas flow controller was installed to maintain the flow rate. It was found that intake air temperature induced the evaporation characteristics of the fuel, and it affects the maximum in-cylinder pressure, IMEP(indicated mean effective pressure), and fuel consumption. As the temperature of intake air decreases, the fuel evaporation characteristics deteriorate even as the fuel temperature has reached the auto-ignition temperature, so that ignition delay is prolonged and the maximum pressure of cylinder is also reduced. Based on the increase in intake air temperature, nitrogen oxides(NOx) increased. In addition, the carbon monoxide(CO) and unburned hydrocarbons(UHC) increased due to incomplete fuel combustion at low intake air temperatures.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1110-1116
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• 1993

A study on optimum operation performances of power efficiency, economy and exhaust emissions for a tractor was conducted. A mathematical model of multiple degree polynomial equation was applied to established the function of solid multiple parameter curves for specific fuel consumption (ge), cabon monoxide (CO) ,hydrcarbons (HC) and cabonaceous smoke (Rb). The optimum operation theorems for economy operation indicated by ge and for exhaust emissions described by Co , HC and Rb were obtained from analytical method and performance test data. The optimum operation theorems could exhibit optimum operation working points, curves, and regions. The optimum matching relations of engine speed and transmission parameters were analyzed by using computer simulation methods in accordance with the tractor specifications , actual farm working conditions in a typical drawbar pull work such as plowing , the optimum operation objective function, the ideal transmission ratio, practical gear shif ing positions and practical travel speed of the tractor TN55 medel. The results of the anlayzes indicated clearly that the optimum power efficient operation, energy saving and pollution reducing would be realized if the tractor would be operated according to theoptimum operation methods.