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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society of Automotive Engineers
Journal Basic Information
Journal DOI :
The Korean Society of Automotive Engineers
Editor in Chief :
Volume & Issues
Volume 23, Issue 6 - Nov 2015
Volume 23, Issue 5 - Sep 2015
Volume 23, Issue 4 - Jul 2015
Volume 23, Issue 3 - May 2015
Volume 23, Issue 2 - Mar 2015
Volume 23, Issue 1 - Jan 2015
Selecting the target year
Analysis of Uncertainties in Estimation of Critical Speeds from Tire Yaw Marks
Han, Inhwan ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 361~370
DOI : 10.7467/KSAE.2015.23.4.361
There will inevitably be errors and uncertainties in tire yaw mark related critical speed formula, which is derived merely from the relationship between the centrifugal force and the friction force acting on the point-mass vehicle. Constructing and measuring yaw marks through appropriate simulation works have made it possible to perform uncertainty analysis in calculation of critical speeds under variation of variety of conditions and parameters while existing yaw mark experimental tests have not performed properly. This paper does not present only the critical speed analysis results for parametric sensitivity and uncertainty of chord and middle ordinate, coefficient of friction and road grade, but also modeling uncertainty such as variation of braking level during turning and vehicle size. The yaw mark analysis methods and results may be now applied in practice of traffic accident investigation.
Structural Design of the Light Weight Axle Beam for Medium Duty Commercial Vehicle Using Hot Press
Sim, Kijoong ; Shin, Hangwoo ; Cho, Wonyoung ; Choi, Gyoojae ; Lee, Youngchoon ; Son, Youngho ; Jeon, Namjin ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 371~379
DOI : 10.7467/KSAE.2015.23.4.371
This paper represents the structural design of the light weight axle beam for medium duty commercial vehicle using hot press. To reduce the weight of the axle, axle beam of solid type was replaced by hollow type which was made by hot press. According to the change of axle beam structure and manufacturing method, we have to investigate the structural strength and fatigue performance. To verify the axle beam performance, the structural analysis was carried out by simplified axle beam model and various design parameters that are axle beam height, thickness and width. From the analysis results, the light weight axle beam structure was founded and applied the full model analysis. This study will be used as a guidance in development of the light weight axle for medium duty commercial vehicle.
Performance Comparison Analysis of Frequency Sensing Shock Absorber and Passive Shock Absorber
Noh, Daekyung ; Seo, Wonjin ; Yun, Jooseop ; Jang, Joosup ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 380~387
DOI : 10.7467/KSAE.2015.23.4.380
Various forms of passive shock absorber have developed to supplement performance which is poorer than that of active shock absorber. It is called 'Hybrid Conventional Damper (HCD)'. Frequency sensing shock absorber that this study will cover belongs to the HCD. This study aims to demonstrate that performance of frequency sensing shock absorber is superior than that of passive shock absorber. Study process is as follows. Firstly, analysis models for both passive shock absorber and frequency sensing shock absorber are developed to secure reliability. Then, elements which cause difference of ride quality are found out through comparison of hysteresis characteristics. By comparison of frequency characteristic, furthermore, damping principle of frequency sensing shock absorber is understood. Also, it determines if the absorber performs well even though maximum excitation speed is changed. Finally, the study proves that performance of frequency sensing shock absorber is superior than that of passive shock absorber after comparing change of damping power in excitation condition that various frequencies are mixed.
Metal Injection Molding Analysis of WGV Head in a Turbo Charger of Gasoline Automobile
Park, Bo-Gyu ; Park, Si-Woo ; Park, Dae-Kyu ; Kim, Sang-Yoon ; Jeong, Jae-Ok ; Jang, Jong-Kwan ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 388~395
DOI : 10.7467/KSAE.2015.23.4.388
The waste gate valve (WGV) for gasoline vehicles operate in a harsh high-temperature environment. Hence, WGVs are typically made of Inconel 713C, which is a type of Ni-based superalloy. Recently, the metal injection molding (MIM) process has attracted considerable attention for parts used under high-temperature conditions. In this study, an MIM analysis for the head and other parts of the WGV is conducted using a commercial CAE program Moldflow. Further, optimal manufacturing conditions are determined by analyzing flow characteristics at various injection times and locations. Moreover, to improve the accuracy of the analysis results, we compare the actual temperature of the mold during injection processing with that observed through the analysis. As the results, metal injection patterns of analysis are well in accord with these of short shot test. And the temperature variations of analysis is also very similar with those of feedstock when metal injection molding.
Development of a Car Door Checker for Reducing Noise in Opening
An, Byeongju ; Son, Sungmin ; Yun, Jaedeuk ; Jung, Yoongho ; Kim, Hyongdon ; Shin, Jongil ; Seo, Seungwoo ; Jang, Kookjin ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 396~401
DOI : 10.7467/KSAE.2015.23.4.396
A door checker holds a car door at several opening angles and limits the maximum door opening, so that the door does not bump against to passengers. Recently, the performance of door checker becomes more important as the feeling of door opening and closing effects on the quality of a car. However, some of door checkers make squealing noise when they are used for ages, which causes consumer's complaints as well as decreasing commercial value of the product. In this study, after various experiments for the noise, we concluded that the major reasons of the noise are acceleration of wearing and loss of lubricant due to impurities in working parts. Therefore, we developed a new mechanism of door checker which can resolve the major reasons of the noise. The developed mechanism is effective to prevent inflow of impurities and loss of lubricant by locating working parts in the case. We also proved that the developed mechanism does not make any noise after the test of 50,000 times of operations.
Quasi-dimensional Analysis of Combustion and Emissions in a Stratified GDI Engine under Ultra-lean Conditions
Lee, Jaeseo ; Huh, Kang Yul ; Kwon, Hyuckmo ; Park, Jae In ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 402~409
DOI : 10.7467/KSAE.2015.23.4.402
In this study a quasi-dimensional model is developed to predict the combustion process and emissions of a GDI engine under ultra-lean conditions. Combustion of a GDI engine condition is modeled as two simultaneous processes to consider significant fuel stratification. The first process is premixed flame propagation described as burning in a hemispherically propagating flame. The second is diffusion-controlled combustion modeled as mixing of multiple spray zones in the burned gas region. Mixing is an important factor in ultra-lean conditions leaving stratified mixture of developing sprays behind the propagating premixed flame. Sheet breakup and Hiroyasu models are applied to predict the velocity of a hollow cone spray. Validation is performed against measured pressures and NOx and CO emissions at different load and rpm conditions in the test engine.
Experimental Study on Natural Gas Conversion Vehicle(1) - Fuel Economy, Emission and Roadability
Kim, Hyung-Gu ; Kim, Inok ; Ohm, Inyong ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 410~419
DOI : 10.7467/KSAE.2015.23.4.410
In this study, the roadability, fuel economy and emission characteristics were evaluated for a natural gas converted vehicle. The results are as follows; Not only the shortage of power was observed in stall test, but also large deterioration of acceleration performance was exposed in roadability. Compared to the original LPG system, the acceleration is 76% in start acceleration and 45 ~ 65% in overtaking acceleration, especially the decline became larger when air conditioner is at work. Furthermore, because the mapping data, which controls the injection depending on driving condition, do not match up with injection system, the failure of air-fuel ratio feedback control occurs resulting from the large gap between the required and the really supplied amount of fuel. This failure cause the exhaust gas to emit without catalytic conversion and the fuel economy based on the fuel heat value to get worse 22% in the mode test and 16% in road test respectively. In addition, the existing injection system does not secure enough fuel at the starting so that it may lead to the fail of clod start, the deterioration of hot start and inharmonic of engine at the idle after start.
Statistical Review for USNCAP on SUV & Pick-up, Part 1: Frontal Crash Test
Beom, Hyenkyun ; Kim, Joseph ; Cho, Kisoon ; Yi, Hoki ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 420~427
DOI : 10.7467/KSAE.2015.23.4.420
This paper statistically reviewed for the USNCAP frontal crash test results carried out by NHTSA. Vehicle samples were selected on total 20 vehicles which were included on 15 vehicles for MPV&SUV and 5 Pickup. The results was summarized as followings. The performance for the driver was better than the passenger's in the average sense. There exist distinctions between the driver and the passenger on the USNCAP front test procedure, for example dummy size, seating position and airbag style. Therefore these differences originated in the statistical results. Main effect was Neck injury for crash performance on both dummies on the average value. Root cause of neck injury was different for each dummy, ie, the driver caused from Nte & Ntf, but the passenger did absolutely Nte mode. Reliability evaluated from the standard deviation was highly dependent upon chest injury on the driver and neck injury on the passenger. Restraint system was also summarized.
Experimental Study of the Effect on Cabin Thermal Comfort for Cold Storage Systems in Vehicles
Lee, Daewoong ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 428~435
DOI : 10.7467/KSAE.2015.23.4.428
This paper presents the experimental study of cabin thermal comfort using a cold storage heat exchanger in a vehicle air-conditioning system. Recent vehicle-applied ISG functions for fuel economy and emission, but when vehicles stop, compressors in the air-conditioning system stop, and the cabin temperature sharply increases, making passengers feel thermal discomfort. This study conducts thermal comfort evaluation in the vehicle, which is applied to a cold storage system for the climate control wind tunnel test and the vehicle fleet road test with various airflow volume rates and ambient temperatures blowing to the cold storage heat exchanger. The experimental results, in the cold storage system, air discharge temperature is
lower than current air-conditioning system when the compressor stops and provides cold air for at least 38 extra seconds. In addition, the blowing airflow volume to the cold storage heat exchanger with various ambient temperature was examined for the control logic of the cold storage system, and in the results, the airflow volume rate is dominant over the outside temperature. For this study, a cold storage system is economically useful to keep the cabin at a thermally comfortable level during the short period when the engine stops in ISG vehicles.
Proposal of a Novel Plug-in-hybrid Power System Based on Analysis of PHEV System
Kim, Jinseong ; Park, Yeongil ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 436~443
DOI : 10.7467/KSAE.2015.23.4.436
In order to develop the PHEV(plug-in hybrid electric vehicle), the specific power transmission systems considering the PHEV system characteristics should be applied. A PHEV applied to series-parallel type hybrid power transmission system is a typical example. In this paper, the novel hybrid power systems are proposed by analyzing the existing PHEV system. The backward simulation program is developed to analyze the fuel efficiency of hybrid power system. Quasi-static models for each components such as engine, motor, battery and vehicle are included in the developed simulation program. To obtain an optimal condition for hybrid systems, an optimization approach called the dynamic programming is applied. The simulation is performed in various driving cycles. A weakness for the existing system is found through the simulation. To compensate for a discovered weakness, novel hybrid power systems are proposed by adding or moving the clutch to the existing system. Comparing the simulation results for each systems, the improved fuel efficiency for proposed systems are verified.
Experimental Study on Natural Gas Conversion Vehicle(2) - Evaluation of Injection System
Kim, Hyung-Gu ; Kwon, Suntae ; Ohm, Inyong ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 444~453
DOI : 10.7467/KSAE.2015.23.4.444
In the previous study, several problems were observed in a NG conversion vehicle, which were fail of air-fuel ratio closed loop control, aggravated fuel economy, increased harmful emission and declined roadability. It was provisionally supposed that the mismatch of injection system with the engine caused these performance deterioration. In this context, the characteristics of fuel injection system of commercial conversion kit for NG were investigated experimentally varying the engine speed, fuel rail pressure and volume. The results are as follows; The injection quantity decreases as the engine speed increases due to the extremely small rail volume of the presenting system and flow rate of No. 2 injector are always lower than that of the other ones regardless of the speed under the dynamic operation condition. Furthermore the existing system does not meet the required fuel quantity for the normal engine operation over 3000 RPM. On the other hands, the large rail volume systems ease and/or eliminate the difference of injection quantity between the injectors according to the speed variation, however, these systems decrease injection flow rate and still cannot supply sufficient fuel. Finally, suitable combination of the higher rail pressure and the larger rail volume might be a solution about these problems.
Improvement of the Correlation between Sled FEA and Test of Vehicle Seatbelt System Using the Statistics Technique
Lee, Kwangseop ; Kim, Dooyong ; Yun, Hongsik ; Lee, Kyeongsang ;
Transactions of the Korean Society of Automotive Engineers, volume 23, issue 4, 2015, Pages 454~461
DOI : 10.7467/KSAE.2015.23.4.454
This study compares the results of a sled test and FEA(Finite Element Analysis) of a vehicle seatbelt system and aims to propose a method to efficiently reduce the error rate in the results of the FEA. This study evaluates the relative importance of potential causes, applying AHP(Analytic Hierarchy Process) technique in order to improve the reliability of the result of the FEA, and draw a highly reliable result of FEA, conducting a Taguchi Method and optimization for reducing the error rate in the FEA through the design of experiments.