• Journal of ILASS-Korea
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• v.28 no.1
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• pp.1-9
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• 2023

In the cylinder of gasoline direct injection engines, the spray targeting from injectors is of great significance for fuel consumption and pollutant emissions. The automotive industry is putting a lot of effort into improving injector targeting accuracy. To improve the targeting accuracy of injectors, it is necessary to develop models that can predict the spray targeting positions. When developing spray targeting models, the most used technique is computational fluid dynamics (CFD). Recently, due to the superiority of machine learning in prediction accuracy, the application of machine learning in this field is also receiving constant attention. The purpose of this study is to build a machine learning model that can accurately predict spray targeting based on the design parameters of injectors. To achieve this goal, this study firstly used laser sheet beam visualization equipment to obtain many spray cross-sectional images of injectors with different parameters at different injection pressures and measurement planes. The spray images were processed by MATLAB code to get the targeting coordinates of sprays. A total of four models were used for the prediction of spray targeting coordinates, namely ANN, LSTM, Conv1D and Conv1D & LSTM. Features fed into the machine learning model include injector design parameters, injection conditions, and measurement planes. Labels to be output from the model are spray targeting coordinates. In addition, the spray data of 7 injectors were used for model training, and the spray data of the remaining one injector were used for model performance verification. Finally, the prediction performance of the model was evaluated by R² and RMSE. It is found that the Conv1D&LSTM model has the highest accuracy in predicting the spray targeting coordinates, which can reach 98%. In addition, the prediction bias of the model becomes larger as the distance from the injector tip increases.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.5
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• pp.615-623
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• 2004

This study was conducted for developing the emission factors of nitrogen oxide(NOx) and carbon monoxide (CO) from the combustion boilers burning liquefied natural gas (LNG). These emission factors were compared with those of U.S. EPA and European Environment Agency (EEA). NOx and CO concentration in the flow gas were measured using Kane-May, KM9106 and Thermo Environmental Instruments Inc., 42C-HL. Measurement were conducted at thirty industrial and commercial LNG boilers. Emission factors were calculated on the basis of fuel consumption (kg-pollutant/㎥-fuel burned). NOx concentration at industrial boiler was 14~125 ppm and it was measured as 35~125 ppm at commercial boiler. NOx emission factors of industrial boiler and commercial boiler were 1.84kg/$m^3$ and 2.09kg/$m^3$, respectively. NOx emission factor of commercial boiler was higher than that of industrial boiler. The NOx emission factors estimated in this study were lower than those of U.S. EPA and higher than those of EEA. Average CO emission factor of industrial boiler was 0.65 kg/$m^3$ and at commercial boiler it was 0.70kg/$m^3$, CO emission factor at industrial boiler was lower than that at commercial boiler.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.764-767
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• 2003

The characteristics of diesel spray have much effect on the engine performances such as power. fuel consumption rate and emissions. Therefore, the measurement of fuel spray characteristics is very important for the improvement of heat engine. The factors which control diesel spray characteristics are injection pressure, ambient temperature and density etc. Spray behaviors are visualized by using the high speed video camera and spray angle, spray penetration are measured. Experimental equations of spray penetration and spray angle were derived by using the experimental results. 1) Ambient temperature and density influence on the characteristics of diesel spray. 2) Experimental equation of spray penetration is expressed as follows 0＜t＜ $t_{b}$ ; $S_1$=11.628$\Delta$ $P^{0.485}$ $\rho$$_{a}$ $^{-0.478}$ $t^{1.337}$, $t_{b}$ ＜t; $S_2$=7.457$\Delta$ $P^{0.523}$ $\rho$$_{a}$ $^{-0.382}$ $t^{0.548}$ 3) Experimental equation of spray Angie is expressed as follows $T_{a}$ =293K; Tan($\theta$/2)=059($\rho$$_{a}$ / $\rho$$_{f}$ )$^{0.437}$, $T_{a}$ =473K; Tan($\theta$/2)=0588($\rho$$_{a}$ / $\rho$$_{f}$ )$^{0.404}$_{f}$ )$^{0.404}$

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2D
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• pp.167-174
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• 2012

Recently, the effort to reduce $CO_2$ emission concerning certified emission reductions (CERs) is progressing lively with the institute in the center through lifecycle. However, the technique for reduce $CO_2$ emission is the first stage yet and the technique is insufficient to calculate with accuracy it. Therefore, this study tries to develop the method to measure by actual time $CO_2$ emission of construction equipment using Zigbee sensor. To review the method that calculate $CO_2$ emission, have classified the impact factors that affect at $CO_2$ emission by IPCC guideline. It also has review the application of Zigbee sensor that use wireless data communication. The reviewed result get that the measuring objects are the $CO_2$ emssion, RPM and fuel consumption of equipment, there are needs to search the year of equipment, waiting time, kind of vehicle and fuel that affect to $CO_2$ emission.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.45-53
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• 2004

An experimental study was carried out to obtain the fundamental data about the effects of radicals induced injection on premixture combustion. A constant volume combustor divided to the sub-chamber and the main chamber was used. The volume of the sub-chamber is set up to occupy less than 1.5％ of that of whole combustion chamber. Radial twelve narrow passage holes are arranged between the main chamber and the sub-chamber. The products including radicals generated by spark ignition in the sub-chamber will derive the simultaneous multi-point ignition in the main chamber. While the equivalence ratio of pre-mixture in the main chamber and the sub-chamber is uniform. We have examined the effects of the sub-chamber volume, the diameter of passage hole, and the equivalence ratio on the combustion characteristics by means of burning pressure measurement and flame visualization. In the case of radical ignition method(RI), the overall turning time including the ignition delay became very short and the maximum burning pressure was slightly increased in comparison with those of the conventional spark ignition method(SI), that is, single chamber combustion without the sub-chamber. The combustible lean limit by RI method is extended to more ER=0.25 than that by SI method. Therefore the decrease of every emission including NOx and the improvement of fuel consumption is anticipated due to lean burn.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.5
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• pp.1-8
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• 2016

Micro turbojet engine test and infrared signal measurement were conducted to understand the characteristics of the engine performance and infrared signal with the variants of the exhaust nozzle configuration. A cone type nozzle and five rectangle type nozzles which has aspect ratio from one to five were used for the experimental work. The results show that there are not much difference between cone and rectangle nozzles of the thrust and specific fuel consumption. However infrared signal from exhaust gas become smaller as increasing aspect ratio.

• Journal of the Korean earth science society
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• v.22 no.3
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• pp.237-247
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• 2001

The concentrations of gaseous mercury (Hg) determined between two different time periods of the late 1980s and the late 1990s were compared to account for the effects of changes between source/sink relationships of atmospheric Hg in an urban area. The Hg concentration levels were different remarkably between the two time periods due possibly to changes in source/sink relationships. The results showed that the Hg levels in the former period were measured to be 14.4${\pm}$9.56ngm$^{-3}$ (N = 2714), whereas those of the latter period were characterized by approximately three-fold decreased values of 5.34${\pm}$3.92 ngm$^{-3}$ (N=2576). Using two independent measurement data sets, we examined the patterns of Hg distribution at different time scales. When analyzed over 24 hour scale, these data sets exhibited two distinctive distribution patterns. The former period showed enhanced concentration levels during daytime, while the latter period showed relative depletion during daytime. The patterns of the two data sets were also examined over seasonal scale. The results of two different time periods consistently showed the occurrences of maximum seasonal values during winter. The former period was characterized by seasonal patterns of fuel consumption with excessive Hg levels during winter. Conversely, no distinctive trend was apparent for the latter period with slight changes in concentration levels across seasons. In order to analyze the factors affecting Hg distributions between two different periods, we conducted both correlation and factor analysis on both all data sets and on seasonally divided data groups. The results of these analyses consistently indicate that the Hg concentration levels for two different time periods are regulated by distinctive source processes that are characteristic of each period.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.48-48
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• 2010

Sound quality and NVH-issues(Noise, Vibration and Harshness) of vehicles has become very important for car manufacturers. It is interpreted as among the most relevant factors regarding perceived product quality, and is important in gaining market advantage. The general sound quality of vehicles was gradually improved over the years. However, today the development cycles in the automotive industry are constantly reduced to meet the customers' demands and to react quickly to market needs. In addition, new drive and fuel concepts, tightened ecological specifications, increase of vehicle classes and increasing diversification(increasing market for niche vehicles), etc. challenge the acoustic engineers trying to develop a pleasant, adequate, harmonious passenger cabin sound. Another aspect concerns the general pressure for reducing emission and fuel consumption, which lead to vehicle weight reductions through material changes also resulting in new noise and vibration conflicts. Furthermore, in the context of alternative powertrains and engine concepts, the new objective is to detect and implement the vehicle sound, tailored to suit the auditory expectations and needs of the target group. New questions must be answered: What are appropriate sounds for hybrid or electric vehicles? How are new vehicle sounds perceived and judged? How can customer-oriented, client-specific target sounds be determined? Which sounds are needed to fulfil the driving task, and so on? Thus, advanced methods and tools are necessary which cope with the increasing complexity of NVH-problems and conflicts and at the same time which cope with the growing expectations regarding the acoustical comfort. Moreover, it is exceedingly important to have already detailed and reliable information about NVH-issues in early design phases to guarantee high quality standards. This requires the use of sophisticated simulation techniques, which allow for the virtual construction and testing of subsystems and/or the whole car in early development stages. The virtual, testing is very important especially with respect to alternative drive concepts(hybrid cars, electric cars, hydrogen fuel cell cars), where complete new NVH-problems and challenges occur which have to be adequately managed right from the beginning. In this context, it is important to mention that the challenge is that all noise contributions from different sources lead to a harmonious, well-balanced overall sound. The optimization of single sources alone does not automatically result in an ideal overall vehicle sound. The paper highlights modern and innovative NVH measurement technologies as well as presents solutions of recent NVH tasks and challenges. Furthermore, future prospects and developments in the field of automotive acoustics are considered and discussed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.116-118
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• 2023

In recent years, the need for economical and sustainable ship routing has emerged due to the enforced regulations on environmental issues. Despite the development of weather forecasting technology, maritime accidents by rough waves have continued to occur due to incorrect weather forecasts. In this study, onboard measurements are conducted to observe the acutal situation on merchant ships in operation encountering rough waves. The types of measured data include information related to navigation (Ship's position, speed, bearing, rudder angle) and engine (engine revolutions, power, shaft thrust, fuel consumption), weather conditions (wind, waves), and ship motions (roll, pitch, and yaw). These ship experiments was conducted to 28,000 DWT bulk carrier, 63,000 DWT bulk carrier, 20,000 TEU container ship, and 12,000 TEU container ship. The actual ship experiment of each ship is intended to acquire various types of data and utilize them for multi-objective studies related to ship operation. Additionally, in order to confirm the sea conditions, the directional wave spectrum was reproduced using a wave simulation model. Through data collection from ship experiments and wave simulations, various studies could be proceeding such as the measurement for accurate wave information by marine radar and analysis for cargo collapse accidents. In addition, it is expected to be utilized in various themes from the perspective of safety and efficiency in ship operation.

• 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.