• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.1114-1119
• /
• 2001

Previously, we have analyzed Vehicle interior noise by dBA based analysis. However, dBA based analysis can not describe the various sound phenomenon that consumer hear. Sound quality matrics can describe various sound phenomenon that dBA based analysis could not explain. In this paper, we will demonstrate the difference of between dBA based analysis and real sound feeling, and analyze sound examples by sound metrics and Principle Component Analysis. In this way we can analyze vehicle interior noise more effectively.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2003.09a
• /
• pp.288-294
• /
• 2003

Increasing the volume of traffic on the roads causes social and economical problems such as increasing air-pollution and distribution cost. Prefabricated light weight bridge becomes a possible solution for these problems in the urban area where it is difficult to construct new one or expend the existing road. There are some merits in this kind of bridge. First, the design live and dead loads are minimized by allowing only passenger cars. Second employing prefabrication construction scheme reduces the construction time. Third, there is no need to buy land if the elevation road is placed on the top of existing one. In seismic design of bridges, base isolation has been an effective solution when the bridge has stiff piers and a heavy superstructure. The prefabricated light weight bridge has different dynamic characteristics from the ordinary bridges. In this paper, the applicability of base isolators such as lead rubber bearing and elastomeric bearing, to prefabricated light weight bridge is examined.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.602-605
• /
• 2008

Recently, it has been trending toward speed-up not only in the passenger car but in the freight car. In this paper, the trend of the market demand for the technology of railway freight cars and the development direction of other country or company were studied by analysing the patent map. The effort for developing the technology is it seems to be more strengthened especially in the parts of bogie, brake, suspension. The increasing rate of the number of patent application from the United States of America is noticeable. The results of this paper can be used for making the development plans of competitive technologies and benchmarking of them.

• Journal of Aerospace System Engineering
• /
• v.3 no.4
• /
• pp.1-6
• /
• 2009

Aerodynamic noise is becoming the major source of annoyance for modern cars recently and is caused by many different noise sources in a car. Appropriate CFD technologies, therefore, have been developed to resolve the noise problems related with aerodynamics. It is necessary for designers to fully understand the relationship between vehicle aerodynamics and wind noise acoustics. In this study, we simulate the flow fields around two different shapes of side mirror models of passenger car and analyze the noise phenomena around one side mirror model that has lower drag than the other model using Fluent 6.3.

• Journal of Hydrogen and New Energy
• /
• v.31 no.6
• /
• pp.522-529
• /
• 2020

This study evaluated the effect of improving the atmospheric environment based on the premise that the supply of hydrogen fuel cell vehicles (HFCV) will be achieved as many as the number of vehicles presented in the hydrogen economy activation roadmap announced by the Korean government in January 2019. The HFCV supply target (2.7 million passenger cars) suggested in the hydrogen economy revitalization roadmap was logically allocated to the five major metropolitan areas in Korea. Air pollution damage costs by region were calculated by reflecting the basic unit of damage cost to the estimated air pollutant emissions. As a result, it was confirmed that the benefits per unit of some cities in Gyeonggi-do were derived more than major cities in the metropolitan area.

• Journal of Institute of Convergence Technology
• /
• v.11 no.1
• /
• pp.25-28
• /
• 2021

Recently, the fire safety of road tunnels has been important issues in South Korea. However, proper fire safety regulations has not made for road tunnels. Due to geographical challenges in South Korea, road tunnels should be constructed to secure stable traffic flows. In the Guidelines for Installing and Managing Disaster Prevention Facilities of Road Tunnels (NFSC 603), main target vehicles are passenger cars. This guidelines cannot support big fires from larger vehicles such as cargo, oil trucks. In this study, fire safety for a road tunnel in port area was analyzed with fire dynamics theory under cargo truck fire scenario. Sujunsan road tunnel in Busan city was chosen as a target tunnel, which links between Busan port and highways to increase cargo shipping. The results show the limitations of present guidelines (NFSC 603) for road tunnel from large fire situations.

• Journal of ILASS-Korea
• /
• v.23 no.4
• /
• pp.212-220
• /
• 2018

As increase the number of vehicles, the issue of greenhouse gas that was emitted by them became important. As a result, greenhouse gas (GHG) regulations are being strengthened and efforts are being actively made to reduce greenhouse gas emissions in the automotive industry. In the other hand, regulations for harmful emission of vehicles have been reinforced by step. Especially, the lastly applied step, so called Euro 6, not only decreased NOx limit down to half of Euro 5 but also introduced real driving emission limit for NOx and PN. It is a challenge for manufacturers to meet the recent GHG regulation as well as the latest emission regulation. To overcome these regulations a De-NOx after-treatment system is being applied to diesel vehicles that are known emitting the lowest GHG among conventional internal combustion engines. At the time of the introduction of Euro 6 emission standard in Korea, in the domestic fuel economy certification test, some diesel vehicles emitted more $CH_4$ than Euro 5 vehicles. As a result, it was confirmed that LNT-equipped vehicles emitted a high level $CH_4$ and the level exceeded the US emission standard. In order to determine the reason, various prior literature was investigated. However, it was difficult to find a detailed study on the methane increase with LNT. In this paper, to determine whether the characteristics of vehicles equipped with LNT the affects the above issue and other greenhouse gases, 6 passenger cars were tested on several emission test modes and ambient temperatures with a environment chamber chassis dynamometer. 2 cars of these were equipped with LNT only, other 2 cars had SCR only, and LNT + SCR were applied to remaining 2 cars. The test result shown that the vehicles equipped with LNT emitted more $CH_4$ than the vehicles with SCR only. Also, $CH_4$ tended to increase as the higher acceleration of the test mode. However, as the test temperature decreases, $CH_4$ tended to decreased. $CO_2$ was not affected by kinds of De-NOx device but characteristic of the test modes.

• Analytical Science and Technology
• /
• v.29 no.3
• /
• pp.136-141
• /
• 2016

In the present study, the distribution of glass particles inside 10 patrol cars of Chungnam Province has been studied. The target seats were front seats (driver’s seat, passenger’s seat) and the back seat. The target areas were the bottom of the seat (seat contacting buttocks, back of the seat, and the corner of the seat (the bottom and back attached part)). The target areas were tape lifted with an adhesive tape. The glass particles adhering to the adhesive tape were examined and counted under a stereomicroscope. The total number of glass particles found was 679. Among them, 471 (driver’s seat 293, passenger seat 178) were collected from front seats, which are usually occupied by police officers. The majority of glass particles were under 0.49 mm size. The results show that the majority of glass particles can be found on the front seats, rather than on the back seat. There is a high probability that glass particles found on the front seat adhere to police officers, so that to get further transferred to the convict upon physical contact (secondary transfer). Thus, there is a risk of misinterpretation of the value of glass evidence in the course of forensic examinations. Hence, a separate method to prevent cross contamination has to be prepared by police authorities as soon as possible.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.8
• /
• pp.4707-4712
• /
• 2014

Considerable fuel in cars is consumed by air resistance. The flow resistance against the air stream was analyzed by flow analysis near the passenger car body. In this study, the models were used were cars available on the real market. Two velocities entered into inlet plane of flow were 80 km/h and 110 km/h using the flow analysis of CFX. As the study method, the velocity of air flow near the car and the pressure on the rear part of car body were investigated at the driving of car. The shapes of the study models were models 1 and 2, and the flow streams were four cases of 1, 2, 3, and 4. In case 1 among the four cases, the maximum pressure ($1.017{\times}10^5Pa$) on the rear part was highest and the maximum velocity (43.81m/s) of air flow near car body was fastest. The air drag force in the case of high speed (110km/h) driving a passenger car was higher than that of a normal driving speed (80km/h). The drag force at wide section area of the car body becomes higher than the narrow section area. The shape of the car body can be effectively designed to reduce the air resistance using the study results of this analysis.

• International Journal of Highway Engineering
• /
• v.8 no.3 s.29
• /
• pp.63-76
• /
• 2006

For a private toll road project, deciding optimal toll is an important element of economic analysis for the project and a challengeable work. In this study, the optimal toll of a private toll bridge, Geoga Bridge which connects Geoje Island of Gyeongnam Province and Gaduk Island of Busan was estimated using Stated Preference (SP) data. The SP data were collected by interviewing the passenger car drivers travelling on the National Road 14. They are latent users of the bridge. A fuzzy approximate reasoning model to estimate the optimal toll was built using the SP data. For the input variable of the model, the saved travel time and toll level were employed and the diversion rate to the bridge was employed for the output variable. The diversion rates for each toll level and saved travel time were estimated and the toll level which had maximized the toll revenue was decided as optimal toll. The optimal toll was tested by comparing with the average pay rate of passenger car drivers. Since the optimal toll for passenger cars at one hour saving, the 6,250 won is about 50 % of the average pay rate of passenger car divers, the toll was evaluated not to be high. The technique employed in this study may be used for the estimation of the optimal tolls for other kinds of vehicles.