• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.476-482
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• 2014

In this study, the characteristics of emulsified fuel and engine emissions were studied with engine dynamometer. Microexplosion took place in the combustion chamber. While combustion, emulsion fuel scattered to micro particles and it caused to smoke reduction. The heat produced from water vapour reduce the temperature of internal combustion chamber and it caused to inhibition of NOx production. It can be verified by the lower exhaust temperature of each ND-13 mode using emulsion fuel than that of MDO fuel. The NOx and smoke concentration were reduced by increasing water content in emulsion fuel. The power also decreased according to the increment of water content of emulsion fuel because emulsion fuel has low calorific value due to high water content than MDO. As a result of ND-13 mode test with 17% moisture content, it was achieved 24% reduction in NOx production, 76% reduction in smoke density, 11% reduction of $SO_2$ and 13% reduction in power loss.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.11
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• pp.999-1004
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• 2010

Recently, many technologies have been developed in order to satisfy stringent emission regulations. However, in the case of diesel engines, the stringent emission regulations with respect to NOx and PM have not yet been satisfied. A dramatic reduction in the NOx and PM emissions could be achieved by using after-treatment systems such as lean NOx trap (LNT) and urea-SCR systems. However, the high temperature in the exhaust pipe affects the spray behavior of the secondary injector, which is used for supplying the Urea-SCR. Because of this high temperature, it is difficult to achieve uniform distribution of the reducing agent in the manifold. In this paper, the characteristics of a urea-SCR injector used for injecting in the exhaust pipe are presented. The purpose of this study was to investigate the spray characteristics of the injector, such as the spray angle, injection quantity, and SMD. In addition, laser diagnostics and high-speed-camera images were used to analyze the injector spray characteristics and to present a distribution of reduction in the transparent manifold.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.183-184
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• 2001

전 세계적으로 철도차량에 의한 대기오염물질은 도로 차량과 기타 산업부문과 비교할 때 비교적 낮은 비율을 차지하지만 점차 미세먼지나 질소산화물의 배출량이 증가하면서 주요 대기오염원으로 부각되고 있다. 최근 미국 등 선진국을 중심으로 배출가스 규제대상을 기존의 도로용 차량에서 비도로용 차량까지 확대적용하고 있으며, 우리나라에서도 이에 대한 대책마련을 서두르고 있다. (중략)

• Journal of the Korean Institute of Gas
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• v.13 no.6
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• pp.39-43
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• 2009

Gasoline engine have proved its utility in light, medium and heavy duty vehicle in every sector of the world community. The concern about long term availability of petroleum and the increasing threat for the environment by the increasing load of vehicular emission, compel the technology to upgrade itself for meeting the challenges. CNG is environmentally clean alternative to the existing SI Engines with out much change in the hardware. Many researchers have found this as a potential substitute to meet the energy requirement. Higher octane number and higher self ignition temperature make it a good gaseous fuel. Although power output is slightly lesser than the gasoline it's thermal efficiency is better than the gasoline for the same SI Engine. Results showed that reduced CO, hydrocarbon emissions is a favorable outcome, with slight increase in NOx emission when compared with gasoline fuel to dual fuel mode in the existing SI Engines.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.1
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• pp.79-85
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• 1984

터어보과급 디이젤 엔진의 저속 및 급가속영역에서 발생하는 매연의 배출을 억제하기 위하여 흡 입 공기량을 증가시키는 방안으로서 흡기관의 동적효과를 이용하기 위한 통합과급 시스템을 개발 하였다. 동조회전수에 있어서 음향임피던스 방법에 의하여 공명흡기관의 칫수를 결정하였고 흡입 공기 냉각기를 부착하여 전 회전영역에서의 흡입공기 밀도비를 증가시켰다. 기존 엔진을 변형한 두가지 시스템을 설계하여 성능측정을 하였으며, 이들에 대한 비교 및 실용성에 관해 자세히 언 급하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.3
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• pp.409-420
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• 2017

The amount of ventilation required in making the tunnel ventilation plan is an important factor for determining the capacity of the ventilation system. The amount of pollutant emission for each type of vehicle (basic emission amount for the design of ventilation volume) for estimating the required ventilation amount is based on the 'Standard for Allowing the Emission for the car manufacturing', proposed by Ministry of Environment. However, in 2013, the Ministry of Environment announced the 'Regulations on the calculation method of total emissions from vehicles' as a regulation for calculating the pollutants emitted from vehicles. In this regulation, there are the 'Emission factors for each type of vehicle'. Therefore, it is necessary to review the application of the Regulation to the estimation of the required ventilation volume for the road tunnel. In this study, the influence of the strengthened emission regulation in 2015 caused by the case of manipulation of emission volume for the diesel vehicle on the calculation of the required ventilation volume in the road tunnel has been checked. In addition, in this study, the required ventilation volume calculated according to the Standard for Allowing the Emission for the car manufacturing revised by Ministry of Environment and "Emission factors for each type of vehicle" and that calculated according to the EURO emission standard were compared for analysis. This study has implications that it provides the basic design data for calculating the reasonable ventilation capacity of the ventilation system based on the ground for calculating the required ventilation volume.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.658-665
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• 2014

Natural gas for marine diesel engine is considered as an important and clean source of energy because of simultaneously reducing the emission of NOx, SOx and GHG. Especially with a appearance of shale gas, the using of natural gas has been investigated aggressively and expected to expand rapidly. By the reports, gas engine and diesel engine were both in a similar performance in the power aspect, and the SFOC of gas engine was shown a little better than that of diesel engine. But the characteristics of exhaust gas emission were different according to various combustion technologies. And with lean burn technology, the emission of NOx could be reduced to 85% lower than that of diesel engine. In this paper, it was described that a simulation program has been developed to predict NOx emission. The developed program is adopted two-zone model and Wiebe function for combustion in cylinder. The effects of premixed and diffusive combustion could be simulated by using the excess air ratio as input data. And it was confirmed that the results of simulation were agreed with the general trends of exhaust gas emission according to various combustion conditions such as lean burn, premixed and diffusive combustion.

• Clean Technology
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• v.12 no.2
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• pp.78-86
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• 2006

Computational analyses are conducted on the combustion characteristics of the coal- and the biomass-derived synthetic gases with low-Btu heating value in gas engine. Using thermochemical analyses on the synthetic gases, combustion pressure, temperature, exhaust gas composition, NO emission and engine power are predicted and the predicted results are compared with small-scale pilot engine test results. In order to investigate the unsteady combustion phenomena in gas engine combustion chamber, CFD analyses are carried out on the coal and the biomass synthetic gases and their computed results are compared to provide the guidelines for the design modification and the tuning of the gas engine burning the synthetic gases as alternative fuels.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.4
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• pp.351-358
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• 2015

In the recent times, the use of gasoline direct injection (GDI) engines has been regarded as a means of enhancing conformance to emission regulations and improving fuel efficiency. GDI engines have been widely adopted in the recent years for their better engine performance and fuel economy compared to those of conventional MPI gasoline engines. However, they present some disadvantages related to the mass and quantity of particulate matter generated during their use. This study investigated the nanoparticle characteristics of the particulate matter exhausted from a GDI engine vehicle installed with different types of gasoline particulate filters, after subjecting it to ultra-lean burn driving conditions. Three metal foam and metal fiber filters were used for each experimental condition. The number concentrations of particles were analyzed for understanding their behavior, and the reduction characteristics were obtained for each type of filter.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.66-73
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• 2021

In this study, The full load test and WHTC mode test were performed to examine the effect on a heavy duty natural gas engine according to the type of standard gas for certification to check engine performance and exhaust characteristics. Two types of standard gas (G_r, G₂₃) and commercially available natural gas were applied as the fuel used. As a result of the test results of three natural gases with different fuel compositions, G₂₃ with a high nitrogen content was inferior in torque, fuel consumption, and thermal efficiency conditions. In addition, when evaluated in the WHTC mode it was possible to obtain a result that satisfies the EURO VI regulation. However, compared to the other two fuels, the emission characteristics of G₂₃ decreased CO2 and CO, but increased CH4, NOx and PN emissions.