• Corrosion Science and Technology
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• v.21 no.6
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• pp.514-524
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• 2022

Carbon emissions from fuel consumption have been pointed by scientists as the cause of global warming. In particular, fossil fuels are known to emit more carbon when burned than other types of fuels. In this regard, International Maritime Organization has announced a regulation plan to reduce carbon dioxide emissions. Therefore, recently, Liquefied Natural Gas propulsion ships are responding to such carbon reduction regulation. However, from a long-term perspective, it is necessary to use carbon-free fuels such as hydrogen and ammonia. Nitrogen oxides might be generated during ammonia combustion. There is a possibility that incompletely burned ammonia is discharged. Therefore, rather than being used as a direct fuel, Ammonia is only used to reduce NO_X such as urea solution in diesel vehicle Selective Catalyst Reduction. Currently, LPG vehicle fuel feed system studies have evaluated the durability of combustion injectors and fuel tanks in ammonia environment. However, few studies have been conducted to apply ammonia as a ship fuel. Therefore, this study aims to evaluate corrosion damage that might occur when ammonia is used as a propulsion fuel on ships.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.1
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• pp.19-28
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• 2024

Environmental regulations are becoming more stringent in response to climate change, especially concerning marine pollution caused by ship emissions. Large ships are adjusting by integrating technologies to reduce pollutant emissions and transitioning to eco-friendly fuels such as low-sulfur oil and LNG. However, small ships face space constraints for installing LNG propulsion systems and the risk of power depletion with pure electric propulsion. Consequently, there's growing interest in researching hybrid propulsion methods that combine electricity and diesel for smaller vessels. Hybrid propulsion systems utilize diverse energy sources, requiring an effective method for evaluating their efficiency. This study proposes employing Bond graph modeling to comprehensively analyze energy dynamics within hybrid propulsion systems, facilitating better understanding and optimization of their efficiency. Modeling of the ship's energy system using Bond graphs will be able to provide a framework for integrating various energy sources and evaluating their effects.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.180-184
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• 2016

Legislative and regulatory actions regarding the exhaust gas from ships are being strengthened by both international organizations and national governments, to protect human health and the environment. Exhaust gas traps are excluded from exhaust gas regulation applications, but, recently, the United States, Britain, and other developed countries have examined a variety of ways to improve the system, including the introduction of electric propulsion systems to prevent air pollution generated by naval ships. This study investigates a large number of smoke problems of naval diesel engines to verify the effect of improving the nozzle characteristics. An exhaust gas emission measurement method to determine the quality of pollutant exhaust gas generated during low-load operation is proposed through the research methodology of the smoke problem. It was confirmed that the emissions value is improved by decreasing the nozzle hole diameter and increasing the injection pressure. At the same time, the flow rate decrease equation and setting up a test memo based on the nozzle diameter confirmed that the fuel consumption, to which the nozzle diameter in the flow path is related, is reduced.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.37-45
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• 2010

Computational simulation has been carried out to examine the effects of pilot injection to reduce both of NOx and Soot emissions in a marine diesel engine. For verification of the computational result, calculated cylinder pressure was matched to experimental pressure. In this study, the primary variables were injection timing, dwell time and injection rate while the amount of injection fuel was maintained constant. It was revealed that variation of pilot injection timing affects auto ignition and heat release rate. In the results, both of NO and soot emission were reduced without deterioration of in-cylinder pressure under the condition of $10^{\circ}$CA dwell time and 0.022kg/s injection rate.

• Journal of Energy Engineering
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• v.18 no.1
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• pp.31-36
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• 2009

There are several types of environment friendly vehicle being developed by auto manufactures. HEV (Hybrid Electric Vehicle) is most applicable one among them in actuality. HEV has two power sources, one is an internal combustion engine, the other one is an electric device. The HEV is developed for reducing fuel consumption and emissions. We selected the diesel engine as a main power source of HEV. The tests were carried out under different driving cycles which was CBDBUS (Central Business Driving Bus Schedule) and HWFET (Highway Fuel Economy Test). This research presents a simulation for the fuel economy and the emission of heavy diesel hybrid vehicle according to the SHEV (Serial Hybrid Electric Vehicle), PHEV (Parallel Hybrid Electric Vehicle), Plug-in SHEV and plug-in PHEV.

• 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.

• Journal of Environmental Health Sciences
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• v.39 no.6
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• pp.541-549
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• 2013

Objectives: We analyzed the characteristics of hazardous air pollutants (HAPs) in road tunnels in Seoul. Methods: Particle matter ($PM_{10}$), elemental carbon (EC), organic carbon (OC), and 16 species of polycyclic aromatic hydrocarbons (PAHs) in two road tunnels (NS tunnel and HJ tunnel) were sampled and analyzed from 2007 to 2011. Results: Levels of $PM_{10}$ and carbon ingredients which were mainly emitted from diesel-fueled vehicles showed a declining tendency in both road tunnels. PAHs levels in HJ were declining slightly while PAHs levels in the NS tunnel fluctuated considerably and showed an increasing tendency. Conclusions: These results suggested that the abatement project of diesel vehicle emissions by the Seoul metropolitan government from 2007 has had an impact on the reduction of DVE into the air, though there exist many things to consider for analyses.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.2
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• pp.203-209
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• 2015

Recently, the portion of electronic control in an engine system has been increasing with the aim of meeting the requirements of emissions and fuel efficiency of the engine system in the construction machinery industry. Correspondingly, the complexity of the engine management system (EMS) has increased. This study developed an engine HiLS system for reducing the cost and time required for function development for the EMS. The engine model for HiLS is composed of air, fuel, torque, and dynamometer models. Further, the mean value method is applied to the developed HiLS engine model. This model is validated by its application to a heavy-duty diesel engine equipped with an exhaust gas recirculation system and a turbocharger. Test results demonstrate that the model has accuracy greater than 90 and also verify the feasibility of the virtual calibration process.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.827-835
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• 1998

The effects of recirculated exhaust gas on the wear of cylinder liner piston and piston rings have been investigated by the experiment with a two-cylinder four cycle indirect injection diesel engine operating at 75% load and 1600 rpm speed For the purpose of comparison between the rates of two cylinders with and without EGR the recirculated exhaust gas is sucked into one of two cylinders after the soot among exhaust emissions is removed by an intntionally designed cylinder-type scrubber equipped with 6 water injectors(A water injector has 144 nozzles of 1.0 mm diame-ter) while only the fresh air into another cylinder. These experiments are carried out on the fuel injection at a fixed $15.3^{\circ}$ BTDC timing. It is found that firstly the mean wear amount of cylinder liner with EGR is more increased in the measurement positions of the second half than of the first half and the mean wear amount without EGR is almost uniform regardless of measurement posi-tions secondly the wear rates of the first and second piston ring(compression ring)thickness with EGR are more than twice but the wear rate of oil ring thickness without EGR is more increased than that with EGR and finally the wear rate of piston skirt with EGR is a little bit increased but the piston hed diameter is rather increased owing to soot adhesion and corrosion wear and espe-cially larger with EGR.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4723-4728
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• 2014

In this study, a thermoelectric module (TEM) and a diesel engine were modeled using 1-D commercial software AMESim, and the performance of the TEM was evaluated when the engine was operated under the NEDC driving cycle. The goal of TEM modeling was to investigate not only the waste heat recovery (WHR) rate and energy converting efficiency, but also the heat transfer rate by taking the materials characteristics into account. In addition, a diesel oxidation catalyst (DOC) was designed, and it was found that the waste heat recovery with TEM affects the activation of DOC and alters engine exhaust composition. The simulation indicated that the WHR using TEM is beneficial for decreasing the fuel consumption of vehicles, but the reduction in the exhaust temperature affects the activation of DOC, resulting in an approximately 14% increase in CO and HC emissions. Therefore, the effect of waste heat recovery on the automotive emission characteristics must be considered in the development of automotive engine WHR systems.