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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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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 18, Issue 6 - Nov 2010
Volume 18, Issue 5 - Sep 2010
Volume 18, Issue 4 - Jul 2010
Volume 18, Issue 3 - May 2010
Volume 18, Issue 2 - Mar 2010
Volume 18, Issue 1 - Jan 2010
Selecting the target year
Microstructural Analysis of Local Tensile Deformation Characteristics in A356 Hollow Sand Cast Chassis Part
Kim, Jae-Joong ; Ko, Young-Jin ; Lim, Jong-Dae ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 1~6
Aluminum rear lower arm is designed for luxury sedan and manufactured by hollow sand casting in the present study. Here we present the relationship between local microstructure and coupon tensile test in the rear lower arm. The characteristics of the local tensile deformation are supposed to be dependent upon Si distribution and DAS (dendrite arm spacing). Si distribution affects the yield strength and DAS affects the elongation of local area in the part, respectively.
A Study on the Exhaust System Model for Thermal Stress Analysis of Exhaust Manifold
Choi, Bok-Lok ; Lee, Kyung-Woo ; Chang, Hoon ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 7~13
In this study, we investigated the efficient FE modelling techniques for thermal stress analysis of the exhaust manifold subject to thermo-mechanical cyclic loadings. At first, full engine model was considered to identify the critical locations and their results were compared to failure site shown by the engine bench test. And the equivalent system model was proposed based on the mechanical behavior of the full engine model. The weak areas of both FE models show a good agreement with the experimental crack location. As a result, a simplified modelling methodology was verified to estimate the thermo-mechanical behaviors of the exhaust manifold under thermal shock test condition.
Matching Simulations with Tests of Cruise Bus Using Multi-body Dynamics Technology
Choi, So-Hae ; Park, Seong-Jun ; Lee, Jeong-Han ; Yoo, Wan-Suk ; Sohn, Jeong-Hyun ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 14~22
In this study, a large bus is tested for measuring the steering response based on the slarom test and step steer test. A full car model by using ADAMS/Car is established for computer simulation. For bus modeling, user defined templates are made and used in the simulation. Simulation results according to the slarom and step steer test are compared to the physical experiments, in which several sensors are installed to measure vehicle responses. The results obtained from the comparison show a good agreement with regard to the vehicle velocity and steering angle.
Development of Average Inverter Model for Analysis of Automotive Electric Drive System
Choi, Chin-Chul ; Bae, Kyu-Tae ; Lee, Woo-Taik ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 23~30
A detailed circuit level model requires a small sampling time to represent high frequency switching behaviors with proper resolution. The small sampling time leads a large execution time to obtain the system analysis results. As the alternative of the detailed circuit model, an averaged PWM switch model was proposed for the rapid system level analysis. There exists a voltage distortion between the reference and output voltage because of non-ideal switching characteristics, such as the dead-time, diode forward voltage drop and conduction resistance. This paper analyzed causes and effects of the voltage distortion. The average inverter model, which reflecting this voltage distortion, is developed for the rapid and accurate analysis of automotive electric drive system in MATLAB/Simulink environment. The rapidity and accuracy of the proposed inverter model is proved through comparison between simulation and experiment.
Study on FWDB Frontal Vehicle Crash Test
Kim, Joseph ; Beom, Hyen-Kyun ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 31~37
In proportion to increasing interest in vehicle safety, many country have regulated vehicle safety and performed NCAP(New Car Assessment Program). However vehicles which had good results in these compliance and NCAP frontal crash test have caused problems such as the fork effect and over-riding in real car-to-car accidents. To complement these issues, new frontal crash test modes using new barrier like FWDB and PDB have been developed by EEVC WG15. In this paper, FWDB frontal crash test was performed and the result was compared with the full frontal crash test using the rigid wall in order to comprehend the characteristic of FWDB. The results of FWDB test were compared with one of USNCAP and KNCAP. Using USNCAP data, vehicle performance like deformation and wall force were studied. A comparative study of dummy injuries was made by using KNCAP result. The results showed that vehicle performance of FWDB test like displacement and effective acceleration was similar in spite of absorbing energy of FWDB due to the greater vehicle deformation of rigid wall test. In FWDB test, driver dummy head bottomed out but most of injuries were superior to the injury of rigid wall test.
The Effect of Ultrasonic Impact Treatment(UIT) for Fatigue Life of Weldment
Song, Jun-Hyouk ; Lee, Hyun-Woo ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 38~45
Welding structures are designed to endure its expected life. The most important factors are life. Especially on welded structure, fatigue strength is critical. So this study performed a research on Box and T shape weldment specimen to examine the influence of welding type. In this experiment, the results indicate Box shape was available in more than T shape. Fatigue tests were performed to evaluate the fatigue strength of the both as-welded and statically pre-loaded specimens by 3 point bending load. Fatigue life can be improved by using Ultrasonic Impact Treatment(UIT) effect. Ultrasonic Impact Treatment(UIT) is excellent for eliminating the tensile residual stresses and generating compressive residual stresses which elevate fatigue strength of welded structures. Also, this shows that welding part has better fatigue life and welding was performed well. In this study, to evaluate the Ultrasonic Impact Treatment(UIT) effect, for welding structure, the experiment was conducted at various levels of stress range between 100MPa and 500MPa. From the test results, it was indicated that fatigue performance was improving by Ultrasonic Impact Treatment(UIT)
Emission Analysis in Catalytic Converter Adopted Secondary Air Injection System for Cold Start Period
Yun, Jeong-Eui ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 46~52
In this paper, emission analysis during cold start period of CVS-75 mode in LPG vehicle was performed to find out proper operating conditions of SAI(Secondary Air Injection) system. In order to meet SULEV target, the simulated emission system had a SAI system as well as a MCC(Manifold Catalytic Converter) and a UCC(Under body Catalytic Converter). Using commercial 1-D code AMESIM, in which 7 step global surface chemical reactions of Langmuir-Hinshelwood type were adopted, transient emission analysis in the exhaust system during cold start period of CVS-75 mode were carried out to figure out the effects of flow rate, duration of supply air on HC, CO, NO emission.
Automotive Airbag Inflator Analysis Using Measured Properties of Modern Propellants
Seo, Young-Duk ; Kim, Gun-Woo ; Hong, Bum-Suk ; Kim, Jin-Ho ; Chung, Suk-Ho ; Yoh, Jai-Ick ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 53~62
An airbag is composed of housing assembly, door assembly, cushion assembly, and an inflator. The inflator is the essential part that generates gas for airbag. When an airbag is activated, it effectively absorbs the crash energy of the passenger by inflating a cushion. In this study, tank tests were performed with newly synthesized propellants with various compositions, and the results are compared with the numerical results. In the simulation of inflator, a zonal model has been adopted which consisted of four zones of flow regions: combustion chamber, filter, gas plenum, and discharge tank. Each zone was described by the conservation equations with specified constitutive relations for gas. The pressure and temperature of each zone of the inflator were calculated and analyzed and the results were compared with the tank test data. In the zone of discharge tank the pressure quickly rose, the pattern of pressure curve was very similar to the pressure curve of real test. And in zone 1 & 2 & 3 the mass of products was increased and decreased with time. In zone 4, the mass of products was increased with time like real inflator. From the similarity of pressure curve in zone 4 and closed bomb calculation the modeled results are well correlated with the experimental values.
The Effect of a Compressive Follower Pre-load on the Ligament of Lumbar Spine and the Relationship with Low Back Pain
Moon, Chang-Hyun ; Chung, Tae-Eun ; Sin, Hyo-Chol ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 63~69
A noble model of the whole lumbar spine (L1~L5) considering all the passive elements, especially the ligaments of the lumbar spine was developed. The purpose of this study was to investigate the relationship between the shear stress of the AVB and the ALL and the effect of a compressive follower pre-load on all ligaments with various motions. The result shows that the shear stress at the AVB and the ALL are positively correlated. This indicates that the shear stress of the ligament can be used an index of low back pain. Regarding the effect of a follower pre-load, contrary to our expectation, the shear stress of the ligaments was not always reduced by applying follower pre-load; flexion was decreased and axial rotation did not change, while extension and lateral bending were increased.
A Study on Optimizing Drying Performance of Air Dryer
Park, Won-Ki ; Lee, Hi-Koan ; Yang, Gyun-Eui ; Mun, Sang-Don ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 70~75
Compressed air represents an energy source and an force-transmission medium for brake systems on medium-heavy and heavy-duty commercial vehicles. However, one disadvantage is the tendency of air to absorb moisture in the form of water vapor. This water vapor condenses once the air, which is heated during compression, cools back to ambient temperature upon emerging from the air compressor. The resulting condensation assumes the form of moisture in pneumatic lines, air tanks, cylinders and valve assemblies and can have negative consequences for the brake system and vehicle safety. The pneumatic systems on today's vehicles are equipped with air dryers, in which the supplied air is dried according to the adsorption principle. In the systems, the compressed air flows through a granular desiccant with molecular sieves which captures the water molecules.
Experimental Investigation on DeNOx Performance according to the Urea-SCR System Control at Various Operating Conditions for Diesel Engines
Han, Jung-Won ; Gong, Ho-Jeong ; Hwang, In-Goo ; Myung, Cha-Lee ; Park, Sim-Soo ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 76~83
Recently, as the current and future emission regulations go stringent, the research of NOx reduction has become a subject of increasing interest and attention in diesel engine. Selective Catalytic Reduction (SCR) is one of the effective technology to reduce NOx emission from diesel engine. Especially, Urea-SCR that uses urea as a reductant is becoming increasingly popular as a cost effective way of reducing NOx emissions from heavy duty vehicles. In this research, we designed urea injector and DCU (Dosing Control Unit) specially developed for controlling the Urea-SCR process onboard vehicles. As passenger and commercial diesel engine experiment, we grasped characteristics of NOx emission and SCR catalyst temperature level in advance. As a result, highest NOx emission level was shown in condition of low engine speed and high load. On the other hand, SCR catalyst temperature was highest at high engine speed and load. On the basis of these result, we conducted the NOx reduction test at steady engine operating conditions using the urea injector and DCU. It was shown that 74% NOx conversion efficiency on the average and 97% NOx conversion efficiency was obtained at high SCR catalyst temperature.
Shape Optimization of an Automotive Wheel Bearing Seal Using the Response Surface Method
Moon, Hyung-Ll ; Lm, Jong-Soon ; Kim, Heon-Young ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 84~90
This paper presents the shape optimization process for the automotive wheel bearing seal lip using the finite element method and the response surface method. First, to predict performance of the bearing seal lip, we used the non-linear finite element analysis. And then, we compared the analysis results with the test results to verify the finite element model. The objective function in optimizing process was obtained from results of the mud slurry test, which is one of many tests for evaluating performance of wheel bearing. After the mud slurry test for the four models which have the similar cross-sectional shape, we measured the wear area of the seal lip and the moisture content in grease. The objective function has been chosen by comparing the results of mud slurry test and characteristics of seal lip, such as contact force, contact area, contact pressure, and interference. Finally, within limited design parameters, we suggested the optimized shape of seal lip, which is expected to improve the wear and the sealing effect of it.
Combustion and Emission Characteristics of Passenger Car Common-rail Diesel Engine with DME Fuel
Lee, Dong-Gon ; Youn, In-Mo ; Roh, Hyun-Gu ; Choi, Seuk-Cheun ; Lee, Chang-Sik ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 91~97
This paper described the effects of DME blended fuel on the engine combustion and emission characteristics of four cylinder CRDI diesel engine. Biodiesel was added into the DME fuel in order to improve the low kinematic viscosity of DME fuel. In this work, the experiment was performed under th various injection timings and injection strategy at constant engine speed and engine load. To maintain the fuel pressure and temperature, pressure and temperature controllers were installed to the DME fuel system. The results show that ignition delay was shortened and combustion duration was extended when DME blended fuel is supplied. Despite of slightly higher NOx emission with DME blended fuel at equal conditions in comparison with those of diesel fuel, the engine showed lower HC and CO emission characteristics.
Combustion and Nano-particulate Emissions Characteristics of a Compression Ignition Engine Fueled with Biodiesel according to EGR Ratio
Cha, June-Pyo ; Yoon, Seung-Hyun ; Lee, Chang-Sik ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 98~104
An experimental investigation was conducted to analyze the effects of EGR ratio on the combustion, exhaust emissions characteristics and size distributions of particulate matter in a single cylinder diesel engine with common-rail injection system fueled with biodiesel derived from soybean. In order to analyze the combustion, exhaust emissions and measurement of size distributions of particulate matter were carried out under various EGR ratio which was varied from 20~60% and the results were compared to those of results without EGR. The experimental results show that ignition delay was extended and maximum value of rate of heat release (ROHR) was decreased according to increasing of EGR ratio. In addition, oxidies of nitrogen (
) emissions were reduced but soot emissions were increased under increasing of EGR ratio. However, under higher EGR ratio region, soot was slightly decreased. And then the particulate size distribution shows that high exhaust gas temperature restrain the formation of soluble organic fraction (SOF) which were beyond the accumulation mode (100~300nm) and lead to increase of nuclei mode particles.
Performance and Emission Characteristics of a Compression Ignition Engine Operated with LPG and Cetane Enhancing Additives
Lee, Seok-Hwan ; Oh, Seung-Mook ; Choi, Young ; Kang, Kern-Yong ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 105~113
In this study, a feasibility test of liquid petroleum gas (LPG) compression ignition (CI) engine has been carried out to study the effectiveness of cetane enhancing additive: Di-tertiary-butyl peroxide (DTBP). Performance and emissions characteristics of a CI engine fuelled with DTBP blended LPG fuel were examined. Also, the effect of EGR (exhaust gas recirculation) on the combustion and emissions characteristics has been investigated. Results showed that stable engine operation over a wide range of the engine loads was possible. Exhaust emissions measurements showed that hydrocarbon were decreased with the blended fuel at enhancing cetane number. Furthermore, the combustion stability of LPG with a cetane number improver was equivalent to that of commercial Diesel fuel. Increasing the EGR rate leads to deteriorate the IMEP (indicated mean effective pressure) and increase the ignition delay. It was found that the exhaust emissions with the EGR resulted in a very large reduction in nitrogen oxides at the expense of higher THC and CO emissions. Considering the results of engine performance and exhaust emissions, LPG blended fuel of enhancing cetane number could be used as an alternative fuel for diesel in a CI engine.
Design Process of Light-weighted Fuel Cell Vehicle Body Frame
Kim, Ki-Tae ; Kang, Sung-Jong ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 114~121
This paper presents a design process of light-weighted fuel cell vehicle (FCV) frame to meet design target of natural frequency in early design stage. At first, using validated FE model for the current design, thickness optimization was carried out. Next. optimization process, comprised of beam model size optimization, shell model design and shell model thickness optimization, was investigated for two frame types. In addition, in order to ensure hydrogen tanks safety against rear impact load, structural collapse characteristics was estimated for the rear frame model finally produced from the previous optimization process and, with the target of equal collapse characteristics to the current design model, structural modification with small weight increase was studied through static structural collapse analyses. The same attempt was applied to the front side frame. The results explain that the proposed process enables to design light-weighted frames with high structural performance in early stage.
Priority Decision based on Users' Requirements for the Development of Military Vehicles
Lee, Bum-Koo ; Cho, Yong-Kun ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 122~129
The military vehicles are necessary to perform various war battle missions but in reality they are not as convenient as the civil vehicles. Thus, it is problematic regarding the satisfaction about convenience, operation, and performances of military vehicles. Since most of military vehicles used in Korea were made by bench-marking the models of United States developed in the latter half of 1970's. It is question whether the current military vehicles can provide the functions and expected performance fully or not if we do not study what the user friendly military vehicles are. This article report soldiers' user satisfaction survey on military vehicles and provide arguments on the priority decision based on users' requirements. Future direction for the development of military vehicles is discussed.
A Study on the Modal Characteristics of a Large-sized Military Truck
Suh, Kwon-Hee ; Lim, Hyeon-Vin ; Song, Bu-Geun ; Chang, Hun-Sub ; Yoo, Woong-Jae ; Oh, Cheol-Jo ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 130~137
Due to test facility and specialty, it is physically difficult to conduct the modal tests of large-sized structures such as truck, bus and airplane. So, in case of a large-sized truck, the mode analysis on a full vehicle model comprised of reliable cabin, frame, and deck has been generally performed. However, the reliability of overall vibrational characteristics of the analytic model has not been fairly guaranteed by the testified models of each subsystem owing to the existence of cab suspension and the nonlinear mounting between a chassis frame and a special deck system. In this paper, a method to find out the modal characteristics of a large-sized military truck is presented. New modal test equipment is developed to set the boundary conditions of three military truck variants as close as a free-free condition. And the mode analysis method using coupled structure and dynamic models is established to consider the above-mentioned dynamic non-linearities of the vehicle itself. The usefulness of the suggested method is verified by comparing with the modal test results. Finally, the modal parameters of the final variant are extracted using the proved analytic method.
Vibration Reduction of a Large-sized Bus Roof through Change of the Factors Characteristics
Kuk, Jong-Young ; Park, Jong-Chan ; Lim, Jung-Hwan ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 138~144
If the vibration is occurred in a large-sized bus roof, it makes people annoying and complaining the quality of a large-sized bus. So in design stage, it must be considered. To assess vibration at the roof which is equipped with air conditioner in design stage, finite element model is constructed. Computer simulation analysis and experimental method are performed. The dynamic characteristics of the large-sized bus are found by using eigenvalue method. It is related with dynamic behavior. The running conditions of a large-sized bus are velocity and road condition which followed experimental conditions. And the frequency response of a large-sized bus is well correlated with analysis result. Modal participation method is used for finding major modes at each peak. Using this method, we found that front and rear suspension system, engine mounting system and roof structure are the major reasons of the roof vibration. To reduce vibration level of roof in a large-sized bus, spring stiffness of front and rear suspension system, spring stiffness of engine mounting system and roof structure are properly combined. From this study, the vibration characteristics of the roof structure of a large-sized bus can be to a satisfactory level.
The Study for Improving the Combustion in a Common-rail Diesel Engine using Swirl Groove Piston
Bang, Joong-Gheol ;
Transactions of the Korean Society of Automotive Engineers, volume 18, issue 6, 2010, Pages 145~151
The performance of a direct-injection diesel engine often depends on the strength of swirl or squish, the shape of combustion chamber, the number of nozzle holes, etc. This is natural because the combustion in the cylinder was affected by the mixture formation process. Since the available duration to make the mixture formation of air-fuel is very short, it is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this paper, the combustion process of a common-rail diesel engine was studied by employing two kinds of pistons. One has several grooves with inclined plane on the piston crown to generate swirl during the compression and expansion strokes in the cylinder in order to improve the atomization of fuel. The other is a toroidal piston, generally used in high speed diesel engines. To take photographs of flame and flaming duration, a four-stroke diesel engine was remodeled into a two-stroke visible single cylinder engine and a high speed video camera was used.