• International Journal of Automotive Technology
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• v.6 no.1
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• pp.15-21
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• 2005

The purpose of this paper is to experimentally investigate the engine pollutant emissions and combustion characteristics of diesel engine fueled with ethanol-diesel blended fuel (bio-diesohol). The experiments were performed on a single-cylinder DI diesel engine. Two blend fuels were consisted of $15\%$ ethanol, $83.5\%$ diesel and $1.5\%$ solublizer (by volume) were evaluated: one without cetane improver (E15-D) and one with a cetane improver (E15-D+CN improver). The engine performance parameters and emissions including fuel consumption, exhaust temperature, lubricating oil temperature, Bosch smoke number, CO, NOx, and THC were measured, and compared to the baseline diesel fuel. In order to gain insight into the combustion characteristics of bio-diesohol blends, the engine combustion processes for blended fuels and diesel fuel were observed using an Engine Video System (AVL 513). The results showed that the brake specific fuel consumption (BSFC) increased at overall engine operating conditions, but it is worth noting that the brake thermal efficiency (BTE) increased by up to $1-2.3\%$ with two blends when compared to diesel fuel. It is found that the engine fueled with ethanol-diesel blend fuels has higher emissions of THC, lower emissions of CO, NOx, and smoke. And the results also indicated that the cetane improver has positive effects on CO and NOx emissions, but negative effect on THC emission. Based on engine combustion visualization, it is found that ignition delay increased, combustion duration and the luminosity of flame decreased for the diesohol blends. The combustion is improved when the CN improver was added to the blend fuel.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.615-622
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• 2010

In this study, a 0D multizone spray-combustion model is developed for the estimation of the performance and NOx emission of medium-sized direct-injection marine diesel engine. The developed combustion model is coupled with the commercial 1D cycle-simulation model, Boost, to analyze the entire engine system, including the intake and exhaust. The combustion model code was generated using Fortran90, and the model was coupled with Boost by connecting the generated code to a user-defined high-pressure cycle (UDHPC) interface. Simulation was performed for two injectors (8 holes and 10 holes) and two engine loads (50% and 100%), and the results of simulation were in good agreement with engine performance test.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.23-32
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• 2013

This paper presents the simulation of the multi-cylinder 4-stroke cycle spark-ignition engine using a commercial simulation tool, AVL BOOST. Various models were examined to select the appropriate models that would best serve to analyze the main components of the intake and exhaust systems-the plenum chamber, the muffler and the exhaust manifold branch junction. For the plenum chamber and the muffler, the tank model and the pipe model were tested. In order to analyze the exhaust manifold branch junction, a complicated model which reflects the actual shape and involves pressure drops was compared to a simplified one. The results show that both the tank model and the pipe model are applicable with satisfying accuracies for the plenum chamber and the muffler. However, the tank model is more desirable in regards to convenience in modeling and efficiency in calculation. Though both the complicated model and the simplified model show satisfying accuracies for the exhaust manifold branch junction, the simplified model is recommended in regards to convenience in modeling and efficiency in calculation.

• Journal of the Korea Fashion and Costume Design Association
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• v.12 no.3
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• pp.43-55
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• 2010

The major advantages to use CAD System are that it reduce time and effort to manufacture products, and also can demonstrate the condition of the final product prior to the actual manufacturing process of the selected design using the simulation programs in CAD system. Specially in weave design, for use as Computer-Aided Weaving system, the complicated Dobby weave can figured out easily through calculating the complex weave plans of multi shafts. As to one of dobby weave structures, Supplementary warp is the warp threads which are in addition to the regular warps of the woven fabrics, and used for decorating the band or expressing some patterns. The purpose of this study is to research the weave design of Supplementary warp using Computer-Aided Weaving system, which is dobby weave design program of Weave Point. For performing this design study, it was researched the classified woven fabrics depending upon weaving processing, Computer-Aided Weaving system, and the characteristic of Supplementary warp fabrics. On the basis of the theoretical research, Supplementary warp was worked for the 24-shafts AVL computer dobby loom that applied to the various patterned images. The design work was done by Weave Point program of dobby weave, and simulated to fabrics before woven into the computer dobby loom. To see the visual images of fashion items, these simulated bobby fabrics were processed by three-dimension modeling through YoungWoo CNI CAD system. All the patterns of the Supplementary warp in this study could be applied for decorating the fashion clothing and accessories.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.64-70
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• 2008

Temperatures of engine head and liner depend on many factors such as spray and combustion process, coolant passage flow and engine related structures. To estimate the temperature distribution of engine structure, multi-dimensional computational fluid dynamics (CFD) codes have been mainly adopted. In this case, it is of great importance to obtain the realistic wall temperature distribution of entire engine structure. In the present work, a CFD-FEM coupling methodology was presented to address this demand. This approach was applied to a real large-size marine diesel engine. CFD combustion and coolant flow simulations were coupled to FEM temperature analysis. Wall heat flux and wall temperature data were interfaced between combustion simulation and solid component temperature analysis via translator by a commercial CFD package named FIRE by AVL. Heat transfer coefficient and surface temperature data were exchanged and mapped between coolant flow simulation and FEM temperature analysis. Results indicate that there exists the optimum cell thickness near combustion chamber wall to reasonably predict the wall heat flux during combustion period. The present study also shows that the effect of cell refining on predicting in-cylinder pressure during combustion is negligible. Hence, the basic guidance on obtaining the wall heat flux needed for the reasonable CFD-FEM coupling analysis has been established. It is expected that this coupling methodology is a robust tool for practical engine design and can be applied to further assessment of the temperature distribution of other engine components.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.92-99
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• 2013

High oil price and global warming problem are being continued all over the world. For this reason, fuel economy and emission of greenhouse gas are regulated by law in many countries. Therefore many companies are researching and producing hybrid electric vehicles (HEVs) which substitute conventional internal combustion engine vehicle. However, these researches and productions are restricted to mainly passenger cars. Because of cost and physical problems, commercial vehicles are difficult to evaluate fuel economy. So simulations are important and it is necessary to know how sensitive parameters that enter into simulation affect. In this paper, forward simulations using AVL Cruise were conducted for analysis of fuel economy for parallel hybrid bus and were repeated by changing each parameter. Based on these results, root mean square errors (RMSE) are calculated for analysis of fuel economy sensitivity. The number of target parameters are 15. These parameters were classified with high and low sensitivity parameter relatively.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.297-308
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• 2017

One of the major engine thermal management system(TMS) strategies for improving fuel economy is to operate the engine in high temperatures. Therefore, this work performed a numerical and experimental study to examine the effect of several different STOs(Starting Temperature of Opening) of wax-thermostat, ranging from $85^{\circ}C$ to $105^{\circ}C$, of gasoline engine on fuel economy and emission characteristics. In this study, a gasoline car equipped with waxthermostat was tested and simulated under FTP-75 and HWFET mode. CRUISE $M^{TM}$ was used to simulate vehicle dynamics, transient engine performance and TMS. The test results showed fuel savings for both drive cycles due to higher STO of $100^{\circ}C$, which is slightly worse than that of $90^{\circ}C$ and amounts between 0.34 and 0.475 %. These controversial results are attributed to experimental errors and uncertainty. The computational results for three STOs, $85^{\circ}C$, $95^{\circ}C$ and $105^{\circ}C$, showed that fuel savings attributed to the application of higher STOs of $95^{\circ}C$ and $105^{\circ}C$ are relatively small and range from 0.306 to 0.363 %. It is also found that the amount of HC and CO emissions from the tailpipe tends to decrease with higher engine coolant temperature because of faster catalyst light-off and improved combustion.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.3
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• pp.241-246
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• 2015

The interest of New Renewable Energy is increasing globally because of the increment of the uncertainty for the energy's supply and demand, and the increment of the frequency in weather anomaly and its damages. One of the New Renewable Energies, Hydrogen receives attention as the future energy that can deal with global environment regulation. Fuel Cell Electric Vehicle (FCEV) is an environment-friendly vehicle that uses Hydrogen as fuel. The electric power for FCEV is generated by chemical reaction with Oxygen from the air and Hydrogen. Hyundai Motor Company (HMC) has developed a proprietary fuel cell system since 2005. In 2012, HMC is the first car maker that mass-produces the ix35 FCEV to the worldwide such as North America, Europe, etc. In order to develop and improve the FCEV technology, data acquisition and analysis of the driving vehicle information is essential. Therefore, the monitoring system is developed, which is consist of datalogger, Automatic Vehicle Location (AVL) server and main server. Especially, WCDMA technology is integrated into the system which enables the data analysis without any restriction of time and region. The main function of the system is the analysis of the driving pattern and the component durability, and the safety monitoring. As a result, ix35 FCEV has successfully developed by using the developed monitoring system. The system is going to take an advantage of development in the future FCEV technology.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.250-256
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• 2014

EV(Electric Vehicle) has many benefits such as prevention of global warming and so on. But due to driving source changing from combustion engine to battery and e-motor, new R&D difficulties have arisen which changing of desired vehicle performance and multidisciplinary design constraints by means of strong coupled multi-physics domain problems. Additionally, dynamics performances of EV becomes more important due to increasing customer's demands and expectations for EV in compare with internal combustion engine vehicle. In this paper suggests model based development platform of EV through integrated simulation environment for improving analyse & design accuracy in order to solve multi-physics problem. This simulation environment is integrated by three following specialized simulation tools IPG CarMaker, AVL Cruise, DYMOLA that adapted to each purpose. Furthermore, control algorithm of TV(Torque Vectoring) system is developed using independent driven e-motor at rear wheels for improving handling performance of EV. TV control algorithm and its improved vehicle performances are evaluated by numerical simulation from standard test methods.

• Tribology and Lubricants
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• v.32 no.4
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• pp.132-139
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• 2016

The piston of a marine diesel engine works under severe conditions, including a combustion pressure of over 180 bar, high thermal load, and high speed. Therefore, the analyses of the fatigue strength, thermal load, clamping (bolting) system and lubrication performance are important in achieving a robust piston design. Designing the surface profile and the skirt ovality carefully is important to prevent severe wear and reduce frictional loss for engine efficiency. This study performs flexible multi-body dynamic and elasto-hydrodynamic (EHD) analyses using AVL/EXCITE/PU are performed to evaluate tribological characteristics. The numerical techniques employed to perform the EHD analysis are as follows: (1) averaged Reynolds equation considering the surface roughness; (2) Greenwood_Tripp model considering the solid_to_solid contact using the statistical values of the summit roughness; and (3) flow factor considering the surface topology. This study also compares two cases of skirt shapes with minimum oil film thickness, peak oil film pressure, asperity contact pressure, wear rate using the Archard model and friction power loss (i.e., frictional loss mean effective pressure (FMEP)). Accordingly, the study compares the calculated wear pattern with the field test result of the piston operating for 12,000h to verify the quantitative integrity of the numerical analysis. The results show that the selected profile and the piston skirt ovality reduce friction power loss and peak oil film pressure by 7% and 57%, respectively. They also increase the minimum oil film thickness by 34%.