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Transactions of the Korean Society of Automotive Engineers
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Journal DOI :
The Korean Society of Automotive Engineers
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Volume & Issues
Volume 17, Issue 6 - Nov 2009
Volume 17, Issue 5 - Sep 2009
Volume 17, Issue 4 - Jul 2009
Volume 17, Issue 3 - May 2009
Volume 17, Issue 2 - Mar 2009
Volume 17, Issue 1 - Jan 2009
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Vehicle Detection Using Edge Analysis and AdaBoost Algorithm
Song, Gwang-Yul ; Lee, Ki-Yong ; Lee, Joon-Woong ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 1~11
This paper proposes an algorithm capable of detecting vehicles in front or in rear using a monocular camera installed in a vehicle. The vehicle detection has been regarded as an important part of intelligent vehicle technologies. The proposed algorithm is mainly composed of two parts: 1)hypothesis generation of vehicles, and 2)hypothesis verification. The hypotheses of vehicles are generated by the analysis of vertical and horizontal edges and the detection of symmetry axis. The hypothesis verification, which determines vehicles among hypotheses, is done by the AdaBoost algorithm. The proposed algorithm is proven to be effective through experiments performed on various images captured on the roads.
Comparison of Rapid Braking Characteristics between an Expert Driver and a General Person
Kim, Kee-Nam ; Lee, Ji-Hoon ; Kim, Min-Seok ; Yoo, Wan-Suk ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 12~18
Skid mark and coefficient of friction are usually utilized to calculate the velocity and behavior of vehicles. For a critical case such as traffic accident reconstruction, however, the initial velocity of the car should be calculated precisely. In this study, in order to estimate the speed at the brake onset, rapid braking tests were executed on the proving ground. We compared with a skid length and wheel locking time of an expert driver and a general person. We verified that the skid mark of expert driver occurs longer than general person's. A new method is proposed to determine the speed of a vehicle at the brake onset of maximum braking, which could be applied to a reconstruction of vehicle with Non-ABS.
Effect of D-Range Neutral Control of Automatic Transmission on LA-4 Mode Fuel Economy
Wi, Hyo-Seong ; Jung, Youn-Sik ; Park, Jin-Il ; Park, Kyoung-Seok ; Lee, Jong-Hwa ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 19~23
This paper focuses on vehicle fuel economy improvement using D-Range neutral control of automatic transmission. The system objected to reducing of fuel consumption during idle. Usually, turbine of conventional auto transmission is mechanically linked to wheel during idling condition. Therefore speed ratio of torque converter is zero for that period. This causes needless power loss by the torque converter slip. To improve this inefficiency automobile makers develops electronically-controlled D-range neutral control system. The D-range neutral control system minimizes slip on the torque converter by shifting gear to a neutral position during vehicle stoped with D-range gear position. However there's insufficient study about the effect of D-range neutral control system on vehicle fuel economy. In this paper, researches are performed on effect of D-range neutral control system on vehicle fuel economy by experiment with two different vehicle. And it is also estimated the effect on vehicle fuel economy using computer simulation. As a result, 1.8% of LA-4 mode fuel economy improvement can be achieved in a vehicle by D-range neutral control system.
Study of Design & CFD Analysis for Partial DPF Utilizing Metal Foam
Yoon, Cheon-Seog ; Cho, Gyu-Baek ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 24~34
DPF(Diesel Particulate Filter)s have been used to reduce the most of PM(particulate matters) from the exhaust emissions of diesel engine vehicles. Metal foam is one of promising materials for the DPFs due to its cost effectiveness, good thermal conductivity and high mechanical strength. It can be fabricated with various pore sizes and struct thickness and coated with catalytic wash-coats with low cost. In order to design metal foam filter and analyze the flow phenomena, pressure drop and filtration experiment are carried out. Partial DPF which has PM reduction efficiency of more than 50 % is designed in this paper. Also, CFD analysis are performed for different configurations of clean filters in terms of pressure drop, uniformity index, and velocity magnitude at face of filter. Filter thickness and the gap between front and rear filters are optimized and recommended for manufacturing purpose.
The Effect of N-butane and Propane on Performance and Emissions of a SI Engine Operated with LPG/DME Blended Fuel
Lee, Seok-Hwan ; Oh, Seung-Mook ; Choi, Young ; Kang, Kern-Yong ; Choi, Won-Hak ; Cha, Kyoung-Ok ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 35~42
In this study, a spark ignition engine operated with LPG and DME blended fuel was studied experimentally. The effect of n-butane and propane on performance and emissions of a SI engine fuelled by LPG/DME blended fuel were examined. Stable engine operation was achieved for a wide range of engine loads with propane containing LPG/DME blended fuel compare to butane containing LPG/DME blended fuel since octane number of propane was much higher than that of butane. Also, engine output operated with propane containing blended fuel was comparable to pure LPG fuel operation. Engine output power was decreased and break specific fuel consumption (BSFC) was increased with the blended fuel since the energy content of DME was much lower than that of LPG. Considering the results of engine output power, bsfc, and exhaust emissions, the propane containing LPG/DME blended fuel could be used as an alternative fuel for LPG.
An Experimental Study on Regeneration Characteristics by Variation of Exhaust Gas Temperature, HC and
Concentrations on DOC-CDPF System
Cho, Yong-Seok ; Lee, Seang-Wock ; Lee, Jung-Sub ; Yoon, Yu-Bin ; Park, Young-Joon ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 43~49
A catalyzed diesel particulate filter (CDPF) causes the progressive increase in back pressure of an exhaust system due to the loading of soot particles. To minimize pressure drop which is generated by CDPF, the filter should be regenerated when it collects a certain quantity of soot. It is important to know characteristics of regeneration of CDPF with various of exhaust gas temperatures and compositions. The oxidation of HC in DOC leads to increase gas temperature of DOC downstream. The increased gas temperature by DOC has an positive effect on CDPF regeneration. This study presents characteristics of regeneration of CDPF with DOC according to various gas composition, such as HC and
concentration. The test-rig is used to control each gas composition and temperature during regeneration of CDPF. Experimental results indicate that the increased concentration of
regenerates DPF more actively. With increasing HC concentration, the gas temperature of CDPF upstream increased due to more oxidation of HC. But excessive supply of HC leads to decrease of
concentration in the CDPF, which makes it hard to regenerate CDPF.
Development of a Lane Keeping Assist System using Vision Sensor and DRPG Algorithm
Hwang, Jun-Yeon ; Huh, Kun-Soo ; Na, Hyuk-Min ; Jung, Ho-Gi ; Kang, Hyung-Jin ; Yoon, Pal-Joo ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 50~57
Lane Keeping Assistant Systems (LKAS) require the cooperative operation between drivers and active steering angle/torque controllers. An LKAS is proposed in this study such that the desired reference path generation (DRPG) system generates the desired path to minimize the trajectory overshoot. Based on the reference path from the DRPG system, an optimal controller is designed to minimize the cost function. A HIL (Hardware In the Loop) simulator is constructed to evaluate the proposed LKAS system. The single camera is mounted on the simulator and acquires the monitor images to detect lane markers. The performance of the proposed system is evaluated by HIL system using the Carsim and the Matlab Simulink.
Assisted Flow Rate Characteristics in Hydraulic Power Steering System
Lee, Byung-Rim ; Ryu, Sang-Woock ; You, Chung-Jun ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 58~63
Flow rate of the power steering oil pump is affected by oil temperature, engine rpm and pressure of pump. In this paper, considering those conditions, approximate model expressed by flow rate characteristics between hydraulic power steering oil pump and steering gear is proposed. Oil pump displacement is considered to be 9.6cc/rev. which is adapted to mid size car. Flow rate of the oil pump is predicted from the proposed model and compared with experimental data. And catch-up is also predicted in each steering wheel speed and is compared with experimental results.
Numerical Modeling to Evaluate Rear Crashworthiness for Round Recliner of Automotive Seats
Kim, Jung-Min ; Lee, Kyoung-Taek ; Kim, Heon-Young ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 64~71
The development of more safe recliners is an important issue in the automotive industry. However, the development of new recliners is costly and take much time because it is typically based on experimental evaluation using prototypes. This study presents the evaluation of rear crashworthiness for round recliner using finite element method. That reduces the number of repeating test and gives an information about stiffness. To evaluate rear crashworthiness, the FMVSS 301 simulation and pendulum impact simulation were performed. The load path on two simulations was observed and compared each other in this paper. Also stress, strain and internal energy was compared. It is attempted the tooth strength simulation using a substructure option on PAM-CRASH.
An Experimental Study on the Improvement of Fuel Economy according to Coolant and Oil Temperature
Cho, Won-Joon ; Kim, Hyung-Ik ; Lee, Ki-Hyung ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 72~79
Recently, the internal combustion engines have focused on reducing the
gas in order to cope with severe regulations for fuel economy. Therefore, various new technologies have been developed. Among them, cooling system is spotlighted because it has great effect on fuel economy. In this study, we measured the friction losses of engine parts according to engine speed and oil temperature. We also obtained optimized oil temperature which has the minimum friction losses. Then, we selected optimized oil temperature range and gave informations of friction losses for each engine parts. In addition, we analyzed relationship between coolant temperature and oil temperature by using engine performance test system. From this experiment, we obtained the database for relationship between coolant temperature and oil temperature. Then, we found the optimal temperature about engine oil. We analyzed BSFC and exhaust emissions by controlling the high coolant temperture. If we controlled coolant temperature more higher, BSFC has a little difference but exhaust emissions such as THC and CO have reduced. By using these experimental results, we predicted that IC engine have more low fuel consumption and exhaust emissions by optimized cooling control strategy.
Design Methodology of Main Bearing Cap by a Finite Element Analysis
Yang, Chull-Ho ; Han, Moon-Sik ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 80~86
Main bearing cap is one of the essential structural elements in internal combustion engine. Main bearing cap guides and holds the crankshaft, withstanding the full combustion and inertia loads of the engine. A seamless design methodology using FEA has been proposed to produce a reliable design of main bearing cap. A Levy's thick cylinder model was applied to calculate the contact pressure between bearing shell and housing bore. A calculated contact pressure at housing bore is within the allowed limit comparing with that from bearing shell model. An adequate FEA model was suggested to obtain reliable solutions for the durability of main bearing cap. 3D global model consists of engine bulkhead, main bearing cap, and bolts. Sub-model consisting of cap and part of bolts is used to get detailed solution of main bearing cap. A very careful contact modeling practice is needed to resolve the convergence problems frequently encountering during combined geometric and material non-linear problems. A proposed methodology has been applied to the main bearing cap model successfully and obtained reliable stress results and fatigue safety factors.
Analysis of Performance and Emissions Characteristics on Gasoline Engine for Hybrid Vehicles with Optimum EGR Rate and the Cylinder Variation of EGR Rate
Park, Cheol-Woong ; Choi, Young ; Kim, Chang-Gi ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 87~95
EGR(Exhaust gas recirculation) provides an important contribution in achieving the development targets of low fuel consumption and low exhaust emission levels on gasoline engine for hybrid vehicles while allowing stoichiometric fuelling to be retained for applications using the three-way catalysts. However, the occurrence of excessive cyclic variation with high EGR normally prevents substantial fuel economy improvements from being achieved in practice. Therefore, the optimum EGR rate in gasoline engine for hybrid vehicles should be carefully determined in order to achieve low fuel consumption and low exhaust emission. In this study, 2 liters gasoline engine with E-EGR system was used to investigate the effects of EGR with optimum EGR rate on fuel economy, combustion stability, engine performance and exhaust emissions. As the engine load becomes higher, the optimum EGR rate tends to increase. The increase in engine load and reduction in engine speed make the fuel consumption better. The fuel consumption was improved by maximum 5.5% at low speed, high load operating condition. As the simulated EGR variation on a cylinder is increased, due to the increase in cyclic variation, the fuel consumption and emissions characteristics were deteriorated simultaneously. To achieve combustion stability without a penalty in fuel consumption and emissions, the cylinder-to-cylinder variations must be maintained under 10%.
Digital Elderly Human Body Modeling Part I : Standard Anthropometry and Exterior/Interior Geometries
Han, Ji-Won ; Choi, Hyung-Yun ; Yoon, Kyong-Han ; Park, Yo-Han ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 96~104
An anatomically detailed elderly human body model is under development. Using the anthropometric database of domestic nation-wide size survey, SizeKorea, a standard size and shape of 50th %tile elderly was constructed. Through the local recruitment process, a male volunteer with 71 years of age, 163cm of height and 63kg of weight has been selected. The exterior (skin) and interior (skeleton and organ) geometries were acquired from whole body 3D laser scan and various medical images such as CT, X-ray, and Ultrasonic of the volunteer. A particular attention has been paid into the combining process of exterior and interior geometries especially for joint articulation positions since they were measured at different postures (sitting vs. supine). A whole ribcage of PMHS which possessed similar anthropometry and age of standard 50th %tile elderly was prepared and dissected for the precise gauge of cortical rib bone thickness distributions. After completing the morphological construction of elderly human body, the finite element modeling will be processed by meshing elements and assigning mechanical properties to various biological tissues which reflect the aging effect.
A Study on Combustion Process of Biodiesel Fuel using Swirl Groove Piston
Bang, Joong-Cheol ; Kim, Sung-Hoon ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 105~113
The performance of a direct-injection type diesel engine often depends on the strength of swirl or squish, shape of combustion chamber, the number of nozzle holes, etc. This is of course because the combustion in the cylinder was affected by the mixture formation process. In this paper, combustion process of biodiesel fuel was studied by employing the piston which has several grooves with inclined plane on the piston crown to generate swirl during the compression stroke in the cylinder in order to improve the atomization of high viscosity fuel such as biodiesel fuel and toroidal type piston generally used in high speed diesel engine. To take a photograph of flame, single cylinder, four stroke diesel engine was remodeled into two stroke visible engine and high speed video camera was used. The results obtained are summarized as follows; (1) In the case of toroidal piston, when biodiesel fuel was supplied to plunger type injection system which has very low injection pressure as compared with common-rail injection system, the flame propagation speed was slowed and the maximum combustion pressure became lower. These phenomena became further aggravated as the fuel viscosity gets higher. (2) In the case of swirl groove piston, early stage of combustion such as rapid ignition timing and flame propagation was activated by intensifying the air flow in the cylinder. (3) Combustion process of biodiesel fuel was improved by the reason mentioned in paragraph (2) above. Consequently, the swirl grooves would also function to improve the combustion of high viscosity fuel.
Modeling and CAE Simulation of Chassis Driveline Test Bench for Vehicle NVH Improvement
Kim, Kee-Joo ; Ju, Hyung-Jun ; Lee, Yong-Heon ; Bae, Dae-Sung ; Sung, Chang-Won ; Baik, Young-Nam ; Sohn, Il-Seon ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 114~119
The authors have investigated the NVH problems of drive system in full vehicle test. However it is difficult to define the NVH problems of driveline system. Since it is hard to measure the rotating part and it is vague that only the drive system induces the NVH problem. Vibration in a driveline is presented in this paper. In the experiment, the rear sub-frame and propeller shafts and axle were composed and mounted with rubber each other. For applying the vibration input instead of the torsional vibration effect of an engine, the shaker was taken. In particular, torsional vibration due to fluctuating forced vibration excitation across the joint between driveline and rear sub-frame was carefully examined. Accordingly, the joint response was checked from experiments and the FE-simulation using FRF (frequency response function) analysis was performed. All test results were signal processed and validated against numerical simulations. In present study, the new test bench for measuring the vibration signal and simulating the vehicle chassis system was proposed. The modal value and the mode shape of components were analyzed using the CAE model to identify the important components affecting driveline noise and vibration. It could be reached that the simplified test bench could be well established and be used for design guide and development of the vehicle chassis components.
Development Methods of Remanufacturing Industry for Resources Recycle
Mok, Hak-Soo ; Jeon, Chang-Su ; Han, Chang-Hyo ; Kwak, Hyun-Soo ; Park, Sang-Jin ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 120~129
Remanufacturing is an industrial manufacturing process. The merits of remanufacturing are to reuse old products to perform like a new product and to save energy, natural resources, landfill space and to reduce air pollution by less re-smelting. This paper proposes a systemic approach for activating the domestic remanufacturing industry. The approach is based on inside and outside regulations to apply remanufacturing companies. And, we analyzed the state and problems of remanufacturing industry for automobile parts. Also 5 essential tactics and 20 detail strategies are suggested. On the basis of the approach, the domestic remanufacturing industry will carry out the cooperation for their competitions.
Modeling and Characteristic Analysis of HEV Li-ion Battery Using Recursive Least Square Estimation
Kim, Ho-Gi ; Heo, Sang-Jin ; Kang, Gu-Bae ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 130~136
A lumped parameter model of Li-ion battery in hybrid electric vehicle(HEV) is constructed and system parameters are identified by using recursive least square estimation for different C-rates, SOCs and temperatures. The system characteristics of pole and zero in frequency domain are analyzed with the parameters obtained from different conditions. The parameterized model of Li-ion battery indicates highly dependant of temperatures. The system pole and internal resistance changes 6.6 and 18 times at
, comparing with those at
, respectively. These results will be utilized on constructing model-based state observer or an on-line identification and an adaptation of the model parameters in battery management systems for hybrid electric vehicle applications.
Modeling and Performance Analysis of SCR
Catalyst for Reducing
Emissions in Diesel Engine
Kim, Young-Deuk ; Kim, Woo-Seung ; Lee, Chun-Hwan ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 137~145
The steady-state kinetics of the selective catalytic reduction (SCR) of
has been investigated over a commercial
catalyst. In order to account for the influence of transport effects the kinetics are coupled with a fully transient two-phase 1D+1D monolith channel model. The Langmuir-Hinshelwood (L-H) mechanism is adopted to describe the steady-state kinetic behavior of the
catalyst. The reaction rate expressions are based on previously reported papers and are modified to fit the experimental data. The steady-state chemical reaction scheme used in the present mathematical model has been validated extensively with experimental data of selective
reduction efficiency for a wide range of inlet conditions such as space velocity, oxygen concentrations, water concentration, and
ratio. The parametric investigations are performed to examine how the
slip from a SCR
catalyst and the conversion of
are affected by the reaction temperature,
feed ratio, and space velocity for feed gas compositions with
ratios of 0 and 0.5.
Experimental Studies on the Performance Characteristics of Heat Exchangers of
Air Conditioning System for Vehicle
Kim, Sung-Chul ; Lee, Dong-Hyuk ; Won, Jong-Phil ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 146~153
The performance characteristics of heat exchangers which consist of a gas cooler, an evaporator and an internal heat exchanger have been investigated at various operating conditions of
air conditioning system by experiments. The heat exchangers were designed for use in the vehicle
air conditioning system, when considering the characteristics of heat transfer and high pressure as
refrigerant. This paper studied the performance of heat exchangers at various compressor speeds and expansion valve openings, and quantified the heat transfer rates and pressure drops. Heat transfer rates at the gas cooler and the evaporator were 6.9 kW and 5.2 kW, respectively, when the compressor speed was 4000 rpm and refrigerant vapor quality at the evaporator outlet was 0.98. Therefore, this paper carried out that the heat exchangers were analyzed to achieve superior performance for the vehicle transcritical
Influential Factors for NO_X Reduction Performance of Urea-SCR System for an In-use Medium Duty Diesel Engine
Kim, Hong-Suk ; Jeong, Young-Il ; Song, Myoung-Ho ; Lee, Seang-Wock ; Park, Hyun-Dae ; Hwang, Jae-Won ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 154~161
This study is a part of project of urea-SCR system development for an in-use medium duty diesel engine. This study shows the effect of ammonia oxidation catalyst and SCR volume on
reduction performance. When AOC(Ammonia Oxidation Catalyst) is not used, the urea injection should be controlled accurately to prevent
slip. However, it is found that the accurate
slip control is not easy without AOC in real engine operating conditions, because
reaction characteristics change with many factors such as exhaust gas temperature and
absorbance on SCR. SCR volume is also one of important design parameters. This study shows that
reduction efficiency increases with increase of SCR volume especially at high space velocity and low exhaust gas temperature conditions. Additionally, this paper shows the emissions of EURO-2 medium duty diesel engine can be improved to the level of EURO-5 with a DPF and urea-SCR system.
Development of Real Time Multibody Vehicle Dynamics Software Part I : Real Time Vehicle Model based on Subsystem Synthesis Method
Kim, Sung-Soo ; Jeong, Wan-Hee ; Lee, Chang-Ho ; Jung, Do-Hyun ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 162~168
The real-time multibody vehicle model based on the subsystem synthesis method has been developed. Suspension, anti roll bar, steering, and tire subsystem models have been developed for vehicle dynamics. The compliance effect from bush element has been considered using a quasi-static method to achieve the real time requirement. To validate the developed vehicle model, a quarter car and a full vehicle simulations have been carried out comparing simulation results with those from the ADAMS vehicle model. Real time capability has been also validated by measuring CPU time of the simulation results.
Development of Real-time Multibody Vehicle Dynamics Software Part II: Preprocessor and Postprocessor Using MATLAB GUI and VR Toolbox
Ha, Kyoung-Nam ; Jeong, Wan-Hee ; Kim, Sung-Soo ; Jung, Do-Hyun ; Tak, Tae-Oh ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 169~175
Real-time multibody vehicle dynamics software has been developed for virtual handling tests. The software can be utilized for HILS(Hardware In the Loop Simulations) and consists of three modules such as a graphical vehicle modeling preprocessor, a real time dynamics solver, and a virtual reality graphic postprocessor for virtual handling tests. In the graphical vehicle modeling preprocessor, vehicle hard point data for a suspension model are automatically converted into multibody vehicle model. In the real time dynamics solver, the efficient subsystem synthesis method is used to create multibody equations of motion for a subsystem by a subsystem. In the virtual reality graphic postprocessor, an animator has been also developed by using Matlab Virtual Reality Toolbox for virtual handling tests.
A Study on the Passenger Airbag Design Parameters Influencing Child Injury
Choi, Won-Jung ; Kim, Kwon-Hee ; Ko, Hun-Keon ; Kim, Dong-Seok ; Son, Chang-Kyu ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 176~181
The passenger airbag(PAB) designed for standard sized adults may induce unexpected results to children in out-of-position(OOP) postures. In this work, using MADYMO software, simulations of the OOP injury of children have been performed with respect to PAB design parameters and child dummy positions. The attention is focused on some details with respect to the injury of 3 and 6 year old children in two OOP postures. Among the various design parameters of the passenger airbag systems, four parameters are selected for the sensitivity analysis of the injury with the Taguchi method: bag folding pattern, vent hole size, position of the cover tear seam and the type of door tear seam. An optimal combination of the parameters is suggested.
Study of Flow Characteristics behind a Sunroof Wind Deflector for Wind Noise Reduction
Lee, Dug-Young ; Yoon, Jong-Hwan ; Shin, Jae-Hyuk ; Kim, Sang-Kon ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 182~189
The noise from the sunroof can be divided into the low frequency buffeting noise and the high frequency turbulence noise generated when a car runs at the high driving speed. The wind deflector suppresses the buffeting noise generation by accelerating the vortex shedding from the front edge of sunroof opening, and guides the flow direction so that air can pass smoothly over the sunroof opening. To reduce the buffeting noise and the high frequency noise, it is very important to locate a deflector in a proper position depending on the driving speed and the sunroof opening width. The deflector's sectional shape also plays an important role in efficiently reducing the buffeting and high frequency noise. In this paper, we determined the optimum deflector's sectional shape and examined the flow characteristics behind a sunroof deflector through CFD analysis with changing the deflector height, the driving speed and the sunroof opening width. It is found that the deflector needs to be located in the higher location to control the buffeting noise by shedding the higher frequency vortices to accelerating vortices from the sunroof front edge. The deflector may act as a new noise source at the high driving speed, then it is desirable to put the deflector at the proper height to reduce the flow fluctuations and the noise generation. We also made a road test to verify CFD analysis results in this study.
Structural Design of an Upper Control Arm, Considering Static Strength
Song, Byoung-Cheol ; Park, Han-Seok ; Kwon, Young-Min ; Kim, Sung-Hwan ; Park, Young-Chul ; Lee, Kwon-Hee ;
Transactions of the Korean Society of Automotive Engineers, volume 17, issue 1, 2009, Pages 190~196
This study proposes a structural design method for the upper control arm installed at the rear side of a SUV. The weight of control arm can be reduced by applying the design and material technologies. In this research, the former includes optimization technology, and the latter the technologies for selecting aluminum as a steel-substitute material. Strength assessment is the most important design criterion in the structural design of a control arm. At the proto design stage of a new control arm, FE (finite element) analysis is often utilized to predict its strength. This study considers the static strength in the optimization process. The inertia relief method for FE analysis is utilized to simulate the static loading conditions. According to the classification of structural optimization, the structural design of a control arm is included in the category of shape optimization. In this study, the kriging interpolation method is adopted to obtain the minimum weight satisfying the strength constraint. Optimum designs are obtained by ANSYS WORKBENCH and the in-house program, EXCEL-kriging program. The optimum results determined from the in-house program are compared with those of ANSYS WORKBENCH.