• Journal of Korean Society of Transportation
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• v.29 no.5
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• pp.107-120
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• 2011

Traffic signal is one of the major factors that affect the amount of vehicle emissions on urban highway. The amount of vehicle emissions in urban area is highly affected by the vehicle's cruising speeds heavily influenced by the traffic signal lighting conditions. It was attempted in this study to trace the changing patterns of the vehicle emissions by collecting the emission data from a set of simulation studies and by categorizing vehicle cruising conditions into four different groups: idling, acceleration, deceleration, and running at a constant speed. Authors propose a simple emission model prepared based on Kinematic theory. The validation test results showed that the amount of the emission estimated by the proposed model was relatively satisfactory compared to the one of the existing model employing the average speed data only as the determinant.

• Journal of Korean Society of Transportation
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• v.34 no.5
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• pp.377-393
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• 2016

Vehicle emissions have been known as a critical factor to give a negative impact on the public health. In particular, particulate matters(PM) and NOx are highly related with respiratory diseases such as asthma. This study aimed at analyzing spatio-temporal patterns of PM and NOx generated from urban freeway traffic. MOVES, which is a well-known emission analysis tool presented by US Environmental Protection Agency(EPA), was applied to estimate PM and NOx based on traffic volume and speed data obtained from Seoul Outer Ring Expressway during January~June, 2012. K-means clustering analysis was used for categorizing the Level of Vehicle Emissions(LOVE) to support more systematical identification of the significance of emissions. Then, spatio-temporal analyses of estimated emissions were conducted by LOVE. Finally, this study proposed a set of strategies to reduce both PM and NOx to enhance public health based on analysis results.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.34-39
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• 2015

Recently, most of the energy consumed in vehicle is derived from fossil fuels. For this reason, the demand for clean, renewable and affordable alternative energy is forcing the automotive industry to look beyond the conventional fossil fuels. Natural gas represents today a promising alternative to conventional fuels for vehicles propulsion, because it is characterized by a relatively low cost, better geopolitical distribution than oil, lower environmental impact, higher octane number and a higher self ignition temperature. Above all, CNG is an environmentally clean alternative to the existing spark ignition engines with the advantages of minimum change. In this study was installed bi-fuel system that a conventional 2 liters gasoline engine was modified to run on natural gas by a gas injection system. Experiments were mainly carried on the optimization of an ECU control strategy affecting the emission characteristics of CNG/Gasoline bi-fule vehicle. The test results shown that CO2 emission in bi-fuel mode was reduced 16% compared to gasoline fuel in the NEDC mode. Also the amount of CO and HC emissions in bi-fuel and gasoline modes were found to equality. But Compared to gasoline, the bi-fuel mode resulted in higher NOx emissions.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.33-41
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• 2015

Dimethyl ether (DME) can be used as a clean diesel alternative fuel due to the high cetane number and low emission, it can also be applied to automotive fuel as a blended liquefied petroleum gas (LPG) because physical properties are similar to those of LPG. In this study, feasibility test of LPG vehicle using blended DME-LPG fuel was investigated. Three types of fuel supply such as LPLi (Liquid phase LPG injection), LPGi (Liquid phase gas injection) and mixer type were selected to consider the LPG fuel-injection system. The performance characteristics of LPG vehicle were examined by using LPG and blended DME-LPG fuel in order to compare the exhaust emissions (CO, THC, $NO_X$) and fuel economy. The emissions and fuel economy of DME-LPG blend fuel were comparable to those of LPG with increasing driving distance.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.9-15
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• 2016

Liquefied petroleum gas (LPG) and compressed natural gas (CNG) are often used as fuel for vehicles because they are clean alternative gas fuels. CNG, as a low-carbon fuel, can contribute to the reduction of greenhouse gas emissions. LPG is often used as fuel for taxis because the performance is almost the same as that of gasoline but the price is lower. In the present study, the exhaust gas and the particle number (PN) of particulate matter, which is a recent environmental issue, were compared between LPG and CNG for the same vehicle. A chassis dynamometer was used to conduct the test according to the Federal Test Procedure (FTP)-75 and Worldwide harmonized Light-duty vehicle Test Procedure (WLTC) modes. The PN values of discharged particles having sizes of 5 nm or larger and 23 nm or larger were measured using two condensation particle counters (CPC). The ratio of carbon dioxide was high in the exhaust gas from the LPG vehicle; the ratio of methane was high in the exhaust gas from the CNG vehicle. The PN values of the emitted particles from the two fuels were similar. The PN values of particles having sizes of 23 nm or smaller were high in the high-speed WLTC mode.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.7-18
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• 2007

There are few studies on air pollution due to vehicle emissions in spite of the importance of this field. Therefore, this study describes trends and suggests implications through analysis relating to existing emissions research. This study has been divided into three areas. The first part is about estimating vehicle emissions. In this part, the authors analyze limits in ways of calculating emissions in the existing macroscopic view and then suggest the development of a model for calculating emissions considering velocity and acceleration. These variables are a function of traffic and individual driving behavior in the microscopic view. The second part is about management techniques for reducing vehicle emissions. The traffic management techniques for reducing vehicle emissions should conform to regional characteristics. The final part is about traffic operation for reducing vehicle emissions. The authors suggest the development of a micro-simulator and then the development of strategies for traffic operation. It is necessary to design better models estimating emissions and then, using real time data, to make a monitoring system simulating emission rates. This study serves as a literature review to make a foundation for further research about emissions research for transportation engineering.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.184-194
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• 2023

Purpose: The purpose of this study is to identify the characteristics of C02 emissions by road before establishing a policy to reduce greenhouse gas emissions. Method: As for the analysis method, the traffic volume and speed of the road were estimated using the traffic Assignment model targeting 27 arterial road axes in Incheon Metropolitan City. And, after estimating CO2 emissions by road axis by applying this, the characteristics of each group were analyzed through cluster analysis. Result: As a result of cluster analysis using total CO2 emissions, CO2 emissions by truck vehicles, and the ratio of truck vehicle emissions to total carbon dioxide emissions, four clusters were classified. When examining the characteristics of each road included in each group, it was analyzed that the characteristics of each group appeared according to the level of impact by CO2 emissions and truck vehicles. Conclusion: It is judged that it is necessary to establish a plan in consideration of CO2 emission characteristics for road CO2 management for greenhouse gas reduction.

• Defense and Technology
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• no.7 s.281
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• pp.66-75
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• 2002

과거 10년전만해도 산업, 난방, 발전 등이 대기오염의 주된 원인이었으나 자동차의 증가로 말미암아 최근에는 자동차의 배기가스 즉 질산화물질(NOx), 일산화탄소(CO), 탄화수소(HC), 총먼지(TSP : Total Solid Particlate), 아황산가스(SO2) 등이 대기를 오염시키는 주요 물질이 되었다. 인구의 증가, 산업의 발달, 경제수준의 향상은 자동차 증가를 촉진시키는데 촉매제 역할을 해왔으며 대도시에서의 자동차에 의한 오염물질 배출량은 앞으로도 차량의 증가와 더불어 가속화할 전망이다.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.91-97
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• 2023

Aging construction machinery and vehicles with old diesel engines usually have a long life span, so they continue to emit harmful emissions. Therefore, replacing these older diesel engines with engines that meet the latest emisstion standard is expected to help improve air quality, and engines with propane fuels, which are easily available at construction sites, can be an appropriate alternative. In this study, a propane fueled engine was developed based on a 6.8-liter CNG engine, and technologies such as gas injectors, exhaust gas recirculation (EGR), and enhanced catalysts were applied. As a result, nitrogen oxides achieved half of the emission performance at the Stage-V level, the latest emission standard, while securing diesel engine output and torque in the same class.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.89-97
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• 2007

The car-dependent traffic system based on highly advanced industrialization and economic growth causes various urban problems including traffic jams, energy consumption, air pollution, noise, car accidents and other issues. Particularly in urban areas, air pollution from motor vehicles is worse than pollution from past industrialization. In this study, therefore, the authors grasped car exhaust reduction effects by using microsimulation and those traffic policies that could make cars flow smoothly, reducing the air pollution in urban areas through analysis on profitability. As a result, the weekday-based car using system has been found most effective as it does not need investment cost. However, this system may be socially unacceptable, as it requires the government to change driver behavior. Therefore, the government needs to first reach a consensus with the citizens regarding this system. This system will also be effective with other alternatives. As a follow-up study, the authors will research citizens' perceived impacts of car exhaust on air pollution through a study on preference and grasp the possibility of applying these study results to real traffic policies.