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21.
J. -M. Koo C. H. Choi Y. Huh C. -S. Seok 《International Journal of Automotive Technology》2008,9(3):323-327
The limited slip differential (LSD) is a device that enables the driving force to be transmitted from one slipping wheel to
the other by temporarily restraining the differential function when unwanted slipping occurs on muddy or icy roads. Many types
of LSD have been developed, such as mechanical lock, disk clutch, viscous coupling, torsen and multiple clutch. This study
designed a new type of hydraulic LSD using a pressure generator base on a trochoid gear pump and evaluated the performance
of the new design. 相似文献
22.
B. J. Shim K. S. Park J. M. Koo M. S. Nguyen S. H. Jin 《International Journal of Automotive Technology》2013,14(2):207-212
By high particulate matter(PM) reduction performance, diesel particulate filter(DPF) is applied to almost all of modern HSDI diesel engine. PM emitted from diesel engine is consist of carbon based and non-carbon based material. Representative carbon based PM is soot. Non-carbon based PM is produced by wear of engine and exhaust component, combustion of lubrication oil and sulphur in fuel. Accumulation of non-carbon based PM affects pressure difference of DPF and thus accuracy of soot mass estimation in DPF can be lowered during normal and regeneration condition when the pressure difference caused by non-carbon based PM is not recognized correctly. Also unevenly accumulated PM inside of DPF can produce locally different exhaust gas temperature and thus it can lower accuracy of soot mass estimation during regeneration. This study focuses on estimation of soot oxidation rate not by conventional pressure difference but by exhaust gas analysis at up and downstream of DPF. Results, strong correlations between CO2 -fuel mass ratio and soot oxidation was observed. 相似文献
23.
In an effort to increase the operational efficiency of highways, South Korea has been increasing its design speed recently. However, the use of higher design speed will also increase construction costs. Moreover, increasing the design speed is expected to have an impact on safety. Hence, there is a strong need to demonstrate that the benefits outweigh the cost of having a higher design speed. This study surveyed a sample of design engineers to determine their awareness of the consequences of increasing design speed and their assessment of the right design speed for an actual rural arterial road. In addition to the survey, a case study of three recently upgraded highways was conducted to determine the changes in traffic volumes, speeds, travel times and accidents. The construction costs associated with the upgrades were also reported. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
24.
Jin Sol Cheon Beom-Seon Jang Ki Ho Yim HoSeong Daniel Lee Bon-Yong Koo Hanbaek Ju 《Journal of Marine Science and Technology》2016,21(2):309-324
Normally, the design slamming pressure on the bottomof a semi-submersible-type floating rig is determined in a simple way using the relative speed obtained from an air-gap analysis. However, few studies have taken a thorough, robust, and deep-background approach to the estimation of design pressure. To investigate the slamming pressure on the bottom of a semi-submersible rig, a simplified deformable stiffened plate of a zero-degree deadrise angle is simulated using the nonlinear FEM software LS-DYNA, which can take the influence of fluid–structure interaction (FSI) into account. Various parametric studies are carried out to examine the effects of structural flexibility, coupling stiffness, mesh size, velocity, stiffener size, and air cushion. The pressure response on the plate by the coupling of fluid and structure is studied and the FSI effect of each parameter is discussed. Then, equivalent transient and static loads that result in the same maximum or permanent deformation as FSI are evaluated for design purposes through a series of parametric studies. 相似文献