• Journal of ILASS-Korea
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• v.23 no.4
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• pp.234-243
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• 2018

Since September 2017, a small diesel vehicle certification test mode has been enhanced from NEDC to WLTC. The main reason for the change of the certification test mode is that the certification test mode of the emission control standard of the diesel vehicle does not sufficiently reflect various driving patterns of the actual roads. Several automakers have developed after-treatment systems such as LNT, SCR, and DPF to meet enhanced emissions regulations. In this study, four small diesel cars were selected for sale in Korea, and the exhaust gas measurement test was performed in the WLTC mode, which reflects the driving characteristics of the actual roads. As a result of test, LNT vehicle exceeded Euro 6 NOx regulation and SCR vehicle satisfied Euro 6 NOx regulation. In addition, both LNT and SCR systems showed high NOX emission characteristics due to speed, RPA and Vxa. For the PN, all test vehicles were fitted with a DPF and met the Euro 6 PN regulations, with similar PN emissions results in LNT and SCR system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.4
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• pp.217-224
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• 2022

Due to the issue of the sustainability in transportation area, the number of electric vehicles has significantly increased. Most automakers have decided or planned to manufacture the electric vehicles rather than carbon fueled vehicles. However, there are still some problems to figure out for the electric vehicles such as long charging time, driving ranges, supply of charging stations. Since the speed of growing the number of electric vehicles is faster than that of the number of charging stations, there are lack of supplies of charging stations for electric vehicles and imbalances of the location of the charging stations. Thus, the location problem of charging stations is one of important issues for the electric vehicles. Studies have conducted to find the optimal locations for the charging stations. Most studies have formulated the problem with deterministic or hierarchical models. In this paper, we have investigated the fluctuations of locations and the capacity of charging stations. We proposed a mathematical model for the location problem of charging stations with the vehicle routing problem. Numerical examples provide the strategy for the location routing problems of the electric vehicles.

• Tribology and Lubricants
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• v.38 no.2
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• pp.70-72
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• 2022

In this study, we report on a power system developed as a decelerator for a driving module in an electric vehicle. The system is to be mounted in a limited space. The research focus was on development of miniaturization, light weight, and high power density. In particular, we aimed to minimize the layout of existing external components as integrated or built-in, and to maximize the power density by applying optimal cooling technology to increased requirements for developing modular power systems applicable to various OEM models. South Korean automakers ranked fourth in global electric-vehicle sales in 2020, but domestic sales are relatively slow. Despite government's expansion in subsidies for eco-friendly cars, consumers are delaying purchases after 2021 considering the cost-effectiveness of electric vehicles. In major European markets, the demand for electric vehicles exceeded the demand for diesel cars, and sales of hybrid cars, which used to represent eco-friendly cars, are slowing down as Toyota, started selling electric vehicles. In this study, the internal lubrication characteristics of a decelerator installed in an electric vehicle were analyzed in terms of the deceleration time while driving. By selecting the proper oil and oil viscosity, it was confirmed that there is no problem in lubricating the bearings and gears of the decelerator.

• The Journal of the Korea Contents Association
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• v.18 no.8
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• pp.573-585
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• 2018

Services for navigation and entertainment through AI-based voice user interface devices are becoming popular in the connected car system. Given the classification of VUI agent developers as IT companies and automakers, this study explores attributes of agent persona and user experience that impact the driver's perceived safety and satisfaction. Participants of a car simulator experiment performed entertainment and navigation tasks, and evaluated the perceived safety and satisfaction. Results of regression analysis showed that credibility of the agent developer, warmth and attractiveness of agent persona, and efficiency and care of the UX dimension showed significant impact on the perceived safety. The determinants of perceived satisfaction were unity of auto-agent makers and gender as predisposing factors, distance in the agent persona, and convenience, efficiency, ease of use, and care in the UX dimension. The contributions of this study lie in the discovery of the factors required for developing conversational VUI into the autonomous driving environment.

• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.153-170
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• 2020

With the recent development of AI and ICT, autonomous vehicles are becoming a reality, and sales of the vehicles equipped with partial autonomous driving technology are also rapidly expanding. In this situation, technology research on autonomous vehicles has been actively conducted, but research on exploring the perception of autonomous vehicles from the user's perspective is relatively insufficient. Therefore, this study categorizes autonomous vehicle users into four types - , , , and . Then, it examines the characteristics of each type. For this purpose, we applied Q-methodology, a qualitative research method, to observe self-referent subjectivity of 32 P-samples using a Q-sample which consists of 34 statements. The results of our study have significance in that they provide domestic and global automakers with strategic directions for technological development and market expansion of autonomous vehicles, and academically provide hypotheses for subsequent quantitative research.

• International Commerce and Information Review
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• v.15 no.2
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• pp.71-82
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• 2013

The automotive supply chain is increasingly complex as automakers seek more profitable solutions with global out-sourcing and manufacturing strategies. In the automotive industry, using returnable plastic containers (RPCs) is very common for domestic operations, but for internationally, it has not been considered by many companies because of issues such as overall distance and difficulty of control. The results of this simulation can help to analyze the interactive and coherent behavior of packaging and supply chain systems. The data obtained from the model can be applied to make substantial decisions for choosing the most profitable packaging types, at the same time as it can lead to designing an optimum supply chain for RPCs used in international supply chains.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.1
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• pp.7-14
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• 2016

This study explores the feasibility of a cold storage system to provide thermal comfort for idle stop and go (ISG) vehicles. ISG function is the most valuable and environmental friendly technology in the current automobile industry. However, when an ISG vehicle stops, meaning when the engine standstill, the air-conditioning system does not work, because the compressor also stops. Therefore, passenger thermal comfort is not maintained, as cold air is not provided in the cabin. Consequently, many automakers have studied electric air-conditioning systems based on electrically-driven compressors or cold storage systems using phase-change materials. The experiments herein were conducted for the feasibility testing of different types of cold storage heat-exchangers, cold storage mediums, and thermo-expansion valves with current air-conditioners. The auxiliary cold storage system, filled with phase-change materials, was located behind the evaporator and almost stacked on top of it. In the experimental results, the air discharge temperature rate of increase was better than the conventional air-conditioning system when the compressor stopped and thermal comfort was maintained with $1.9{\sim}4.3^{\circ}C$ decreases within 60 seconds. The #1 cold storage heat-exchanger (CSH), #2 thermo-expansion valve (TXV) and #2 phase change material (PCM) were chosen because of the best temperature rise delay. It was concluded that a cold storage system is an effective solution for ISG vehicles to maintain thermal comfort during short engine stops.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.905-910
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• 2010

Exhaust manifolds are the first structures to be developed by hydroforming; mass production of exhaust manifolds by this method will be possible soon. This is obviously related with tight emission regulation induced by environmental problems commonly for both domestic and worldwide and standards, thus evoking its solution for domestic automakers. Compared to conventional cast products, thin-gauge tubular hydroformed exhaust manifold have superior features; for example, in the hydroformed exhaust manifold, gas decomposition during the cold-start period of the engine is reduced by lowering the heat sink, and manufacturing process is simplified since less welding is involved. The aim of this study is to develop a hydroformed exhaust manifold; the study deals with the components, the hydroforming process, and tool design of the manifolds. The performance of the exhaust system is evaluated by performing flow analysis, heat-transfer analysis, heat-stress analysis, and fatigue analysis by using a computer.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.6
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• pp.465-473
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• 2008

Type II compressed natural gas(CNG) storage vessels for automobiles have been acknowledged for their excellence and have recently become established in local regions. Their supply is not only to automakers in Korea such as Hyundai Motors but they are being increasingly exported. Although the available products have undergone safety evaluations and are certified by an authorized institution they are still short of the optimal design that is possible for such storage vessels. This research investigates the shape and thickness of the dome with the aim of optimizing the type II CNG storage vessels by using a finite element analysis technique. CNG storage vessels can be largely divided into 3 parts namely, the hear part, the cylinder part and the dome part. The head part is designed by means of a hot spinning process and this method is safer than that used in the design of the dome part even though its shape is similar. The thickness of the liners and reinforcing materials was optimized based on the requirements of the cylinder and dome parts. In addition, the shape of the dome, which is most suitable for Type II CNG storage vessels, is proposed by a process of review and analysis of various existing shape, and then conducting a structural stability evaluation to ensure the optimal design plan.

• Knowledge Management Research
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• v.18 no.3
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• pp.1-35
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• 2017

This study conducted comparative study on autonomous car's industry policy and corporate strategy of US, China, Germany, Japan and Korea. By analyzing core technologies and industry paradigm shifts of autonomous car industry, I was able to figure out autonomous car has high potential to be dominant transportation in the future and it is important to construct core competency in technology area. The meaningful findings by analyzing various primary and secondary data are as followings: First, in case of US, Google was leading autonomous car industry by developing its own OS and Platform. US government has been actively supporting and interacting with private firms and Universities for stimulating industry/technology convergence and establishing standard. Second, in case of Germany, autonomous car development was leading by several auto makers such as Mercedes, BMW in Hardware and manufacturing area, and German government was focusing on deregulations for private company. Third, in case of Japan which quite similar with German situation, they were both independently developing technology and expanding alliances with MNCs. And Japanese government was supporting triple helix system construction between local companies and universities. Fourth, in case of China, autonomous car industry was leading by IT companies, and various cooperations between IT companies and automakers were established. Chinese government was regulating foreign companies and supporting domestic companies both in market and technologies Last, in Korean case, the active and extensive alliances were lacking in Korean companies while strategic and strong government supports were missing in public sector. For competing with other countries and players, more active collaboration between different countries and strong policy supports are needed in Korean auto industry.