• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.198-206
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• 1999

An automobile outside rear view mirror system has been analyzed and designed to reduce vibration with a finite element model. model analysis is conducted for the calculation of natural frequencies. harmonic analysis is utilized to estimate the displacements of the glass surface under dynamic loads. The model is verified with the vibration experiment of the parts and the assembled body. The structure of the mirror system is optimized for the robustness defined by the Taguchi concept. At first, many potential design variables are defined. Final design variables are selected based on the amount of contribution on the objective function. That is, sensitive variables are chose. The SN ratio in the Taguchi method is replaced by an objective function with the mean and the standard deviation of the quality characteristic. The defined objective function is appropriate in the structural design in that the vibration displacements are minimized while the robustness is improved.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1366-1375
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• 2002

In cold forging of piston-pin for automobile parts, the flow defect appears by the dead metal zone. This appearance evidently happens in products with a thin piercing thickness for the dimension accuracy and the decrease of material loss. The best method that can prevent flow defect is removing dead metal zone. The purpose of this study is to investigate the material flow behavior of forward-backward extruded piston-pin through the relative velocity ratio and the stroke control of upper moving punch & container using the flow control forming technique. The finite element simulations are applied to analyse the flow defect, then the results are compared with the plasticine model material experiments. The model experiment results are in good agreement with the FE simulation ones.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.427-428
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• 2006

In this study, three dimensional(3-D) orifice model was developed fur automobile trunk hinge. Using that model the flow analysis was conducted to estimate pressure tendency of orifice model according to the variations in the design factors such as oil viscosity and orifice size.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.1004-1006
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• 2014

This study was conducted to improve the understanding of factors affecting an automobile seat cushion in dynamic conditions. When there are two dummies on the seat to measure each places respectively at once, the shape of the transfer function changes because the dummies affect each other as if they are linked with some kind of a spring when under excitation. A simple two-degree-of-freedom linear model is used to define a translational stiffness of dynamic coupling phenomenon. The cushion deflection model was created to find the relation between dynamic coupling and distance. Experimental set-up was made to compare with the two-degree-of-freedom linear model. The dynamic coupling factor could be utilized to improve the dynamic comfort of automobile seats.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.5
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• pp.15-22
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• 2014

The automobile cruise control system tries to maintain a constant velocity in the face of disturbance mainly caused by mass changes or changes in the slope of a road. The controller should compensate for such disturbances and model uncertainties. In this paper, we study on the disturbance observer based controller for cruise control system. In the presence of disturbances and model uncertainties, we carry out computer simulations in order to compare the performance of the conventional PI controller and DOB controller. From the simulation results, we found that the performance of DOB controller is superior to that of the conventional PI controller.

• Construction Engineering and Management
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• v.16 no.6
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• pp.32-40
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• 2015

• Journal of the korean Society of Automotive Engineers
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• v.17 no.6
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• pp.1-5
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• 1995

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.979-988
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• 2014

Recently, the interest in the thermal comfort is ever increasing as the time people stay in the automobile is gradually increasing. So far, however, the cooling performance of the HVAC(heating and ventilation air conditioning) system is evaluated by thermal environment criteria such as indoor air velocity and temperature, not by a thermal comfort index. Furthermore, the precise criteria has not been established yet when the thermal comfort for the automobile is evaluated using numerical analysis. In this study, the numerical analysis of automobile indoor thermal comfort according to various parameters such as HVAC operating mode, airflow, passenger boarding conditions is performed during the HVAC system's initial operating time(20 minutes). The solar ray tracing model and S2S radiation model are used and validated to simulate an external heat source. Based on this study, an evaluation model which can predict the thermal comfort index for the combination of the above parameters is presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.460-465
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• 1997

In the begining stage of development of a new automobile, decision of appropriate positions and room of resonators is important to NVH engineers. To find optimized positions of resonators of an automotive intake system, numerical approach such as acoustic FEM or BEM and experimental work are possible. However, either method requires many efforts and time to prepare a numerical or a real model. This research demonstrates easy way to design an adequate intake system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.2
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• pp.240-253
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• 1996

The refrigeration cycle of automobile air-conditioners is simulated in an effort to provide a computational tool for optimum thermodynamic design. In the simulation, thermodynamic and heat transfer analysis was performed for the four major components : evaporator, condenser, compressor, and expansion valve. Effectiveness-NTU method was used for modeling both evaporator and condenser. The evaporator was divied into many subgrids and simultaneous cooling and dehumidifying analysis was performed for each grid to predict the performance accurately. Blance equations were used to model the compressor instead of using the compressor map. The performance of each component was checked against the measured data with CFC-12. Then, all the components were combined to yield the total system performance. Predicted cycle points were compared against the measured data with HFC-134a and the deviation was found to be less than 5% for all data. Finally, the system model was used to predict the performance of CFC-12 and HFC-134a for comparison. The results were very reasonable as compared to the trend deduced from the measured data.