• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3102-3107
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• 2008

This paper was focused on the particulate matter (PM) on the gasoline and bio ethanol. Bio ethanol as a clean fuel is considered one of the alternative fuels that decreased the PM emission from the vehicle. Particle formation in SI engine was depended on the fuel and engine operating condition. In this paper, Particle number concentration behaviors were analyzed by DMS500 (Differential Mobility Spectrometer) and CPC (Condensation Particle Counter) instrument which was recommended by PMP (Particle Measurement Programme). Particle emissions were measured with various engine operating variables such as air excess ratio ($\lambda$), spark timing and intake valve opening (IVO) at part load condition. In vehicle test, the number of particulate matter was analyzed with golden particle measurement system, which was consist of CVS (Constant Volume Sampler), particle number counter and particle number diluter.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.3
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• pp.302-312
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• 2012

Underwater vehicles play a very important role in underwater engineering. Water-tight junction box (WJB) is one of the key components in underwater vehicle. This paper puts forward a pressure self-adaptive water-tight junction box (PSAWJB) which improves the reliability of the WJB significantly by solving the sealing and pressure problems in conventional WJB design. By redundancy design method, the pressure self-adaptive equalizer (PSAE) is designed in such a way that it consists of a piston pressure-adaptive compensator (PPAC) and a titanium film pressure-adaptive compensator (TFPAC). According to hydro-mechanical simulations, the operating volume of the PSAE is more than or equal to 11.6 % of the volume of WJB liquid system. Furthermore, the required operating volume of the PSAE also increases as the gas content of oil, hydrostatic pressure or temperature difference increases. The reliability of the PSAWJB is proved by hyperbaric chamber tests.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.10
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• pp.1041-1049
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• 2013

One of the causes of malfunction of commercial vehicle is corrosion or wear. In order to prevent corrosion and wear, lubricants have to be supplied periodically. However, the period of lubrication usually depends on operator's judgment. If the period is too short, excess lubricant will cause pollution and unnecessary expenses, where as long periodic supply of lubricant might cause wear, damage and eventual breakdown. Therefore, an automatic lubrication system with predetermined interval will reduce the excessive supply of lubricating oil and prevent wear and damage. This thesis presents an automatic lubrication system which consists of a lubricant pump and an embedded controller. An automatic lubrication operating algorithm is used to operate the lubricant pump and feedback the pressure status of the system using pressure sensors. The developed system shows an efficient periodic supply of lubricant.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.483-488
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• 2013

The psychoacoustic quality of ABS is now considered more important than before as the focus of recent ABS function is expanded to basic function from typical emergency function. Thus, the automotive parts manufacturing companies are actively working to improve NVH (Noise, Vibration, and Harshness) in ABS module. In terms of time, test place, and cost, however, it is very inefficient to have all the operating noise validation test in real vehicle configuration especially for partially improved ABS module. To contribute to reducing the development period and to grasping the improvements faster, this research presents the study of a correlation to predict ABS operating noise inside vehicle via HILS rig test. The regression equation in this paper was statistically drawn from using Minitab S/W, and based on that equation, the noise spectrum of vehicle interior was analogized.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.575-584
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• 2021

This study contains the process of developing a Mission Planning System (MPS) of an USV that can be applied in real situations and verifying them through HILS. In this study, we set the scenario of a single USV with limited operating time. Since the USV may not perform some missions due to the limited operating time, an objective function was defined to maximize the Mission Achievement Rate (MAR). We used a genetic algorithm to solve the problem model, and proposed a method using a 3-D population. The simulation showed that the probability of deriving the global optimal solution of the mission planning algorithm was 96.6% and the computation time was 1.6 s. Furthermore, USV showed it performs the mission according to the results of the MPS. We expect that the MPS developed in this study can be applied to the real environment where USV performs missions with limited time conditions.

• Journal of ILASS-Korea
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• v.28 no.2
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• pp.62-67
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• 2023

Recently, the global automobile industry is aiming for a transition from internal combustion locomotives to zero-emission vehicles. Electric vehicles powered by battery energy can operate at peak performance and improve fuel economy by applying multiple motors or multi-speed transmissions. In order to design a two-speed transmission, it is necessary to evaluate and analyze the application system and performance of electric vehicles. In this study, control performance optimization of a twostage battery electric vehicle equipped with an AMT-based automatic transmission was performed and performance according to control pattern changes was analyzed. In order to improve the operating efficiency of the motor, the shift control that sets the optimal operating point according to the vehicle speed and required torque was derived from the motor efficiency map. The performance of battery energy consumption and transmission loss energy according to the hysteresis interval was analyzed and optimized. The hysteresis interval applied to the optimal shift map acted as a factor in reducing the frequency and loss of shifts. It has been shown that keeping the hysteresis interval at about 4 km/h can reduce energy consumption while reducing the number of shifts.

• Korean System Dynamics Review
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• v.8 no.2
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• pp.5-23
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• 2007

According to the system dynamics model of this study, if there is a significant network effect on vehicle operating costs, it is difficult to achieve the shift to AFV even in the long term without a policy intervention because the car market is locked in to the current structure. Network effect can be caused by an increasing return to scale in fuel supply sector as well as in maintenance service sector. It is also related to the fact that the reliability and awareness of consumers on new products increases with the growth of the market share of the new products. There are several possible policy options to break the 'locked in' structure of car market, such as subsidy on vehicle price (capital cost), subsidy on fuel (operating cost) and niche management policy. Combined policy options would be more effective than relying on a single policy option to increase the market share of AFV.

• Journal of Industrial Technology
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• v.17
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• pp.87-93
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• 1997

A Special purpose program, based on the dimensional analysis, was developed to estimate the wide band turbulent noise in the blower of vehicle airhandling system. Acoustic power level was measured at 4 rating points around the operating condition. The experiment was performed on the reference blower model using international standard chamber, which could measure acoustic power according to the air-handling performance. Analytical model of the blower noise was determined by the measured data. Using the analytical acoustic model, it was possible to estimated the effect by the change of the operating condition, such as flow rate, static pressure and wheel rotating speed, furthermore, the diameter and the width of blower.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.913-917
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• 2007

The turbocharger for a vehicle is consisting of a centrifugal compressor and turbine. These compressor and turbine are vibrating and emitting noises through the T/C body, exhaust system (Catalyst, Bellows, Pipe, etc) and Intake system (Hoses, Intercooler pipes, Intercooler) as rotating. A turbocharger cold test bench is constructed to reduce these noises, especially for the purpose of realizing transient operating environment and oil temperature control to simulate the vehicle operating characteristics with intake system and exhaust system. This research laid the groundwork to develop a lower noise level T/C through understanding the mechanism of the noise source of T/C.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1502-1509
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• 2011

This Paper presents characteristic analysis in terms of interior permanent magnet synchronous motor for electric vehicle propulsion using numerical analysis. Torque ripple analysis, thermal analysis, demagnetization analysis of permanent magnet and mechanical stress analysis with variable operating condition are presented. According to these characteristic analysis, both the performance of motor and possible problems during the operation are examined thoroughly in advance.