• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.263-270
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• 2010

In this study, an air cleaner is considered to improve comfort, safety, and health of automobile passengers. The performance and installation conditions of the air cleaner have been studied to investigate their effects on the air quality in the cabin room using numerical analysis. A five-passenger sedan and a seven-passenger minivan that have comparatively large indoor volume have been considered. The distributions of the local mean age and the volume averaged age of indoor air are calculated according to the variation of the placement and the air flow of the air cleaner. In addition, a decrease of contamination concentration, especially VOCs(volatile organic compounds), by the air cleaner is numerically analyzed with time-accurate unsteady calculation to quantify the effect of the air cleaner on the indoor air quality. As a result, the effective installation and operation conditions of the air cleaner for the automobile cabin room could be suggested.

• Journal of Mechanical Science and Technology
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• v.14 no.4
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• pp.418-425
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• 2000

Recently, many passenger cars have adopted automatic transmissions for shifting gears, and thus the smooth and precise control of gear shifts of passenger car automatic transmissions has become more and more essential for the riding comfort of vehicles equipped with automatic transmissions. In this article, a neural network-based supervisor for an automotive shift controller considering the throttle opening, variations in throttle opening, and the driving load is presented. For using the driving load information, an observer-based driving load estimation algorithm is proposed. A proportional-integral-derivative controller along with an open loop controller is used as a low level controller for controlling the gear shifts, and a supervisory controller for properly adapting the shift control parameters of the low level shift controller is designed using ANFIS. To evaluate the control performance of the proposed supervisor-based shift controller, both simulation studies and experimental studies are performed for various shifting situations.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.154-162
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• 2004

In this study, a mathematical model for analyzing the shifting transients of the passenger car with an automatic transmission is proposed. The proposed model comprises a power transmission system and a vehicle system, which are coupled. In order to extract the modeling parameters, on-road car test is carried out. The model is composed of a detailed powertrain, an engine/AT housing, a simplified suspension system, tires and a vehicle body model. On the test, the vehicle accelerations and pitch ratio are measured by using accelerometers and a gyro sensor. The speeds, the brake signal, and the throttle position are taken from sensors which already exist in the vehicle. Considering natural ftequencies, which is calculated from the measured accelerations, and the characteristic equation, vehicle model parameters are identified. Dynamic behaviors during upshift or downshift are simulated using the proposed vehicle model. By comparing and analyzing the simulation result and on-road car test data, the vibration of the Engine/AT housing influences the shifting transients. The effect of model parameters are also studied. Among model parameters, the location of engine mountings influences the vibration of the vehicle body.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.5
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• pp.444-452
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• 2010

This paper presents design and performance evaluation of electro-rheological(ER) shock absorber for electronic control suspension(ECS). In order to achieve this goal, a cylindrical ER shock absorber that satisfies design specifications for a mid-sized commercial passenger vehicle is designed and manufactured to construct ER suspension system for ECS. After experimentally evaluating dynamic characteristics of the manufactured ER shock absorber, the quarter-vehicle ER suspension system consisting of sprung mass, spring, tire and the ER shock absorber is constructed in order to investigate the ride comfort and driving stability. After deriving the equations of the motion for the proposed quarter-vehicle ER suspension system, the skyhook controller is implemented for the realization of quarter-vehicle ER suspension system. In order to present control performance of ER shock absorber for ECS, ride comfort and driving stability characteristics such as vertical acceleration and tire deflection are experimentally evaluated under various road conditions and presented in both time and frequency domain.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.214-222
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• 2012

Driver's feeling is variously affected by lots of components such as engine, frame, wheels, and seats during the operation of automobiles. The main objective of this research is to identify the correlation between subjective evaluation and vibration metrics that was set by ISO to investigate development of the car vibration quality index using multiple linear regressions(MLR). A previous research related with automotive vibration quality used the method of calculating acceleration values of the point of a seat, a seat back, foot as RMS for objective evaluation. The automotive comfort is determined by RMS values. In comparison with the previous research, this study includes not only the vibration metrics, but also subjective values by jury evaluation. By indentifying the correlation between subjective evaluation and vibration metrics, the automotive vibration quality index is developed through MLR. Based on the results of this study, the proposed the automotive vibration quality index which developed through MLR will be helpful to obtain objective and reliable automotive comfort values.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.123-134
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• 1999

Nowadays since the automobile is regarded as the third living space, comfortable conditions are required in the passenger compartment. The customer's concern on air-conditioning/heating, ventilation and demisting/defrosting performances has been much increased. Both ventilation and demisting /defrosting performances are directly influenced by register location, shape of regist guide vane, ventilation flow rate, air distribution , and air circulation pattern. Diffuse plume of air from the register is desirable not only to maintain comfort when the comfort when the comfortable condition has been satisfied but to improve demisting /defrosting performance. In this study, experimental and numerical investigation about the flow field of six different register vane types were carried out , respectively. The numerical analysis, based upon the $textsc{k}$-$\varepsilon$ turbulence model , was applied to the air flow field. The results show that the shape of register guide vane should be considered as an important design paramter.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.228-230
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• 2006

While trains perform a complete precision stopping control at stop point, it is essential to keep better commuters comfort in prompt. Because a train's brake force tends to increase a brake effort in a low speed and a low brake effort, a brake force in motor cars must be increased to keep better passenger comfort, to control the special braking qua1ities and to prevent the impact of the automatic coupler rather than trailer's, Rail cars must have a special braking process for the train stopping control. In the train stop mode, the train stopping control is designed to start at 20km/h. It starts by Dynamic brake blending, and then finally stops by only the friction. If these process are not exactly activated, the train may fail a complete precision stop. In this report, it studied the electric and friction brake processing during the precious stopping control. To achieve exact test results, the speed reference has to be reduced the calculated difference. In the precision stopping control. the ways of the keeping brake force in motor car was analyzed and some solutions of controling air pressure was brought up by means of direct test in main line, This study was based on line 5 in Seoul Metropolitan subway.

• Journal of Power System Engineering
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• v.14 no.3
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• pp.33-38
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• 2010

Technology of vehicle industry has been developing and it is required a better vehicle performance than before. Therefore, the consumers are asking not only an economic efficiency, functionality, polished design, ride comfort and silence but also a driving stability. The ride comfort, silence and driving stability are influenced by the size of vehicle and various facilities. But the principal factor is a room noise and vibration sensed by a driver and passenger. Thus, the NVH of vehicle has been raised and used as a principal factor for evaluation of vehicle performance. The primary objective of this study is an optimized design of powertrain mounting system. To optimized design was applied MSC.Nastran optimization modules. Results of dynamic analysis for powertrain mounting system was investigated. By theses results, design variables was applied 12 dynamic spring constant. And the weighting factor according to translational displacement and rotational displacement applied 3 cases. The objective function was applied to minimize displacement of powertrain. And the design variable constraint was imposed dynamic spring constant ratio. The constraint of design variable for objective function was imposed bounce displacement for powertrain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.683-688
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• 2012

Driver's feeling is variously affected by lots of components such as engine, frame, wheels, and seats during the operation of automobiles. The main objective of this research is to identify the correlation between subjective evaluation and vibration metrics that was set by ISO to investigate development of the car vibration quality index using multiple linear regressions (MLR). A previous research related with automotive vibration quality used the method of calculating acceleration values of the point of a seat, a seat back, foot as RMS for objective evaluation. The automotive comfort is determined by RMS values. In comparison with the previous research, this study includes not only the vibration metrics, but also subjective values by jury evaluation. By indentifying the correlation between subjective evaluation and vibration metrics, the automotive vibration quality index is developed through MLR. Based on the results of this study, the proposed the automotive vibration quality index which developed through MLR will be helpful to obtain objective and reliable automotive comfort values.

• Journal of IKEEE
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• v.23 no.1
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• pp.224-229
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• 2019

Seat of automobile is required to support the comfort to driver and passenger during the driving. The control method of the seat position is changed from manual type to power type, which means using the motor to increase the comfort of the driver. By using the motor, several problems, such as vibration, noise, and over-current, appeared. These problems can be reduced through the control of seat motor. In this study, a control technology of four control variables, which determine profile of the input voltage applying to the seat motor, is proposed to generate the current profile having soft-start and soft-stop. The current flowing through the coil by input voltage is described by mathematical modeling of power seat. It is confirmed that optimized current profile having soft-start and soft-stop can be generated from simulation using the mathematical model.