• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.20-27
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• 1999

The proportion of diesel vehicle is very high in this country . PM and NOx emitted from diesel-posered vehicle is severely ;affecting to be air quality . Especially, diesel particulate matters(DPM) including black smoke are hazardous air pollutants to human health and environment. In order to reduce the exhaust emissions from diesel engines, it is necessary to analyze the characteristics of exhaust emissions from diesel engines in various driving conditions. Recently, there are occasion to increase the fuel consumption rate to engine power up. So, in this study we have tested a diesel engine detached from in use -diesel vehicle and analyzed exhaust emission by driving condition and fuel dispersion rate. From this results, we will prepare the comprehensive management plan for exhaust emissions from diesel vehicles and contribute to the improvement of air pollution in urban area.

• Korea Petroleum Association Journal
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• s.292
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• pp.24-27
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• 2014

환경부에서는 1990년대 말경 대기오염 문제를 해결하기 위한 방안으로서 디젤 버스를 CNG 버스로 대체하고자 CNG 탱크 추가 등으로 가격이 비싼 CNG 버스에 대하여 보조금을 지급하고 CNG 충전 인프라를 구축하는 등의 지원정책을 실시하여, 현재 국내에서 운행하는 버스는 일부 소도시를 제외하면 대부분 CNG 버스로 대체되었다. 이러한 CNG 버스 정책으로 인하여 당시만 해도 매연 배출이 심하던 디젤 버스로 인한 공해물질이 줄어들고 대기질이 어느 정도 개선된 효과를 거두었다. 최근들어 환경에 대한 중요 이슈의 개념이 변화하고 있으며 자동차 기술도 새로운 변모를 보여주고 있는 것이 현실이기 때문에 CNG 버스만으로 운영되는 정책이 향후에도 계속 유지가 되어야 할지 다시 한번 생각해보아야 할 필요가 있다.

• 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.

• 기계와재료
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• v.25 no.3
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• pp.92-105
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• 2013

전 세계는 지구온난화와 고유가시대를 맞이하여 배출가스 규제에서 온실가스와 연비 규제로 확대되면서 그린카라는 새로운 용어가 등장하였다. 원유 고갈과 원전 불안으로 수송연료에도 신재생 에너지와 세일가스 등장에 큰 기대를 걸고 있으며, 새로운 에너지원을 사용하는 전기자동차와 수소연료전지 자동차의 개발도 활발이 진행되고 있으나 자동차시장의 형성은 각종 규제의 만족은 물론이고 경제성, 안전성, 편리성 등이 수반되어야 한다. 향후 세계 자동차시장은 에너지의 수급 사정과 시대의 요구 조건에 따라 크게 좌우되므로 각 국가별 여건을 고려하여 단계를 구분해서 그 시대에 가장 적합한 그린카 차종이 무엇인지를 신중하게 분석하여 산업화 정책을 추진해야 할 것이다. 이러한 관점에서 최근 기계연구원이 주축이 되어 개발하여 운행 중인 디젤하이브리드 자동차를 중심으로 세계 그린카 개발동향을 소개하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.196-205
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• 2016

The exhaust gas discharged by cars not only threatens the health of the human body, but also contributes to global warming, due to the resulting increase in the concentrations of ozone, fine dust and carbon dioxide. Therefore, the government has steadily implemented careful inspection systems for exhaust emissions, in order to efficiently regulate the exhaust gas of cars. Studies on reducing the exhaust emissions of automobiles have been conducted in various fields, including ones designed to reduce the generation of HC, NOx, and $CO_2$ in the exhaust emission of vehicles. However, there have been insufficient studies on the reduction of the exhaust emission for old diesel vehicles. To develop careful inspection systems for the exhaust emissions of old diesel vehicles, studies on the reduction of the exhaust emissions and improvement of power are necessary by cleaning the carbon sediment in both the intake manifold and injector. Therefore, in this study, we analyzed and compared the amounts of gas emitted when simultaneously cleaning or not cleaning the intake manifold and injector of diesel automobiles with mileages over 80,000 km and operating periods over 5 years. The experimental results showed that in the case where the intake manifold and injector were simultaneously cleaned, there was a decline of 75.2% in the gas emission compared to the cases where only the manifold or injector is cleaned. Also, it was found that simultaneously cleansing the intake manifold and injector enabled the exhaust standard to be satisfied for less than 30% within 8.5 sec.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.23-34
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• 2009

In the railroad rolling stock depot, long-term maintenance tasks is done regularly every two or four year basis to maintain the functionality of equipments and rolling stock body or for the repair operation of the heavily damaged rolling stocks by fatal accidents. This paper addresses the computer simulation model building for the rolling stock maintenance shop for the CDC(Commuter Diesel Car) and Generator Car planned to be constructed at Daejon Rolling Stock Depot, which will be moved from Yongsan Rolling Stock Depot. We evaluated the processing capacity of two layout design alternatives based on the maintenance process chart through the developed simulation models. The performance measures are the number of processed cars per year, the cycle time, shop utilization, work in process and the average number waiting car for input. The simulation result shows that one design alternative outperforms another design alternative in every aspect and superior design alternative can process total 340 number of trains per year 15% more than the proposed target within the current average cycle time.

• Journal of Korean Society of Steel Construction
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• v.18 no.4
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• pp.437-446
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• 2006

Open-steel-plate-girder(OSPG) bridges are one of the most prevalent bridge types among Korean railway bridges. They account for about 40% of all Korean railway bridges. However, the line-type bearings used for OSPG bridges generate several problems with respect to the bridges' dynamic behavior and maintenance. The replacement of the existing bearings with polyurethane disk bearings could be a possible solution to this problem. This type of disk bearing is an elastic bearing using a polyurethane disk. This study estimated the variations in the natural frequency of a bridge when disk bearings were installed and the bridge's dynamic behavior with a running locomotive and running trains. The first natural frequency of the bridge was 3% lower than that of the as-built bridge after the installation of the disk lower, respectively. Also, the second and third frequencies were 7 and 15% lower, respectively. The disk bearings increased the vertical displacement of the bridge, but the pure displacement, excluding the disk deformation, did not vary. The vertical acceleration did not increase when the disk bearing was installed, with trains running. The shear pin in the disk bearing reduced the lateral displacement and the acceleration of the bridge.