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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 24, Issue 5 - Sep 2016
Volume 24, Issue 4 - Jul 2016
Volume 24, Issue 3 - May 2016
Volume 24, Issue 2 - Mar 2016
Volume 24, Issue 1 - Jan 2016
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A Task Scheduling Strategy in a Multi-core Processor for Visual Object Tracking Systems
Lee, Minchae ; Jang, Chulhoon ; Sunwoo, Myoungho ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 127~136
DOI : 10.7467/KSAE.2016.24.2.127
The camera based object detection systems should satisfy the recognition performance as well as real-time constraints. Particularly, in safety-critical systems such as Autonomous Emergency Braking (AEB), the real-time constraints significantly affects the system performance. Recently, multi-core processors and system-on-chip technologies are widely used to accelerate the object detection algorithm by distributing computational loads. However, due to the advanced hardware, the complexity of system architecture is increased even though additional hardwares improve the real-time performance. The increased complexity also cause difficulty in migration of existing algorithms and development of new algorithms. In this paper, to improve real-time performance and design complexity, a task scheduling strategy is proposed for visual object tracking systems. The real-time performance of the vision algorithm is increased by applying pipelining to task scheduling in a multi-core processor. Finally, the proposed task scheduling algorithm is applied to crosswalk detection and tracking system to prove the effectiveness of the proposed strategy.
New Weight-reduction Design of the Fifth Wheel Coupler with a Trailer by Using Topology Optimization and Durability Tests
Kim, Cheol ; Lee, Seung-Yoon ; Lee, Yong-Choon ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 137~143
DOI : 10.7467/KSAE.2016.24.2.137
The fifth wheel coupler is a heavy automotive coupling structure which connects a tractor and a trailer used for heavy-duty trucks widely. It is subjected to various loads simultaneously such as rolling, pitching and yawing loads as well as coupling frictional and impact loadings. Most of existing couplers have been overdesigned and, therefore, it is necessary to reduce the dead weight to increase the fuel efficiency. The topology optimization was applied in order to find conceptual layout designs which could show major load paths and ribs locations, and then the size structural optimization was performed in order to determine the heights and thicknesses of coupler ribs with the predetermined various loading conditions for the development of a new slim coupler with a minimum weight and high enough strength and stiffness. As the results of the topology optimum design, an efficient new coupling structure for truck trailers was designed. The weight of the new fifth wheel coupler was reduced by 4.9 %, compared with the existing one, even though all strength requirements were satisfied. The fatigue test of the new coupler was performed with cyclic vertical loads (+78.4 to +235.2 kN) and horizontal loads (-91.2 to +91.2 kN) simultaneously at 1 Hz and the life of 2,000,000 cycles were achieved without failure.
Exhaust Gas Emission and Particulate Matter (PM) from Gasoline, LPG and Diesel Vehicle Using Different Engine Oil
Jang, Jinyoung ; Lee, Youngjae ; Kwon, Ohseok ; Woo, Youngmin ; Cho, Chongpyo ; Kim, Gangchul ; Pyo, Youngdug ; Lee, Minseob ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 144~151
DOI : 10.7467/KSAE.2016.24.2.144
This study effect of engine oils on regulated fuel economy and emissions including particulate matter (PM) to provide basic data for management of engine oil in vehicles. Three engine oils (Group III base oil, Group III genuine oil with additive package and synthetic oil with poly alpha olefins (PAOs)) were used in one gasoline, one LPG(liquefied petroleum gas) and two diesel vehicles. In the case of diesel vehicles, one is a diesel vehicle without DPF (diesel particulate filter) other is a diesel vehicle with DPF. In this study, the US EPA emission test cycle FTP-75, representing city driving, was used. HORIBA, PIERBURG, and AVL gas analyzers were used to measure the fuel economy and regulated emissions such as CO, NOx, and THC. The number of PM was measured using a PPS (pegasor particle sensor). And, the shape of PMs was analyzed by SEM (scanning electron microscope). The effects of oil type on fuel economy, exhaust gas, and PM were not significant because engine oil consumption by evaporation and combustion in the cylinder is very tiny. Fuel and vehicle type were dominant factors in fuel economy and emissions. HC emission from gasoline vehicles was higher than that from other vehicles and NOx emission from diesel vehicles was higher than that from other vehicles. The number of PM was not affected by the engine oil, but by the driving pattern and fuel. The shapes of the PM, sampled from each vehicle using any test engine oil, were similar.
Characteristics of Simultaneous Removal of NOx and PM over a Hybrid System of LNT/DPF + SCR/DPF in a Single Cylinder Diesel Engine
Kang, Wooseok ; Park, Su Han ; Choi, Byungchul ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 152~160
DOI : 10.7467/KSAE.2016.24.2.152
The market demand for diesel engine tends to increase in general passenger cars as well as commercial vehicles because of its advantages. However, to meet the vehicle emissions regulation which will be more stringent in the future, it is necessary to plurally apply all after-treatment technologies such as diesel oxidation catalyst (DOC), catalyzed diesel particulate filter (CDPF), lean NOx trap (LNT) and selective catalytic reduction (SCR), and so on. Accordingly, the exhaust after-treatment system for diesel vehicle requires the technology of minimizing the numbers of catalysts by integrating every individual catalysts. The purposes of this study is to develop hybrid exhaust after-treatment device system which simultaneously uses LNT/DPF and SCR/DPF catalyst concurrently reducing NOx and particulate matter (PM). As the results, the hybrid system with
generated at LNT/DPF working as a reducing agent of SCR/DPF catalyst, improving NOx conversion rate, was found to be more excellent in de-NOx performance than that in LNT/DPF alone system.
Evaluate the Effect of the Intake Manifold Geometry on Cylinder-to-cylinder Variation Using 1D-3D Coupling Analysis
Park, Sangjun ; Cho, Jungkeun ; Song, Soonho ; Cho, Jayun ; Wang, Taejoong ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 161~168
DOI : 10.7467/KSAE.2016.24.2.161
CNG engine has been used as a transportation because of higher thermal efficiency and lower CO2 and particulate matter. However its out put power is decreased due to cylinder-to-cylinder variation during the supply of air-fuel mixture to the each cylinder. It also causes noise and vibration. So in this study, 1D engine simulation model was validated by comparison with experiment data and 3D CFD simulation was conducted to steady-state flow analysis about each manifold geometry. Then, the effects of various intake manifold geometries on variation were evaluated by using 1D-3D coupling analysis at engine speed of 2100 rpm range in 12 L CNG engine. As a result, variation was improved about 4 % though 3D CFD analysis and there was a variation within 3 % using 1D-3D coupling analysis.
Study on Evaluation Method of Flow Characteristics in Steady Flow Bench(3) - Velocity Profile(1)
Park, Chanjun ; Sung, Jaeyong ; Ohm, Inyong ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 169~182
DOI : 10.7467/KSAE.2016.24.2.169
This paper is the third investigation on the evaluation methods of flow characteristics in a steady flow bench. In the previous works, several assumptions used in the steady flow bench were examined and the flow characteristics were estimated both by the conventional impulse swirl meter and a particle image velocimetry at 1.75B position. From these works, it was concluded that the assumption of the solid rotation might cause serious problems and both of the eccentricity and the velocity profile distort the flow characteristics when using the ISM at 1.75B plane. Therefore, the understanding of the detail velocity profiles is very important to keep discussing the issues about the steady flow evaluation method. For this purpose, the planar velocity profiles were measure at 1.75B position by particle image velocimetry and the characteristics were examined according to the valve angles and lifts. The results show that the planar velocity profiles of 11, 16,
valve angle heads according to the lift are similar to each other, however, that of
angle is an exceptional case in the all aspects. In addition, the swirl behaviors are not apparent up to 6~8 mm lift under the
angle and somewhat arranged motions are observed over the whole plane near the highest lift. At this point, the narrower the angle, the lower the lift at which the swirl motions become clear. On the other hands, when the angle is
, the center of swirl is always farthest from the cylinder center and only the indistinct swirl is observed even if at the highest lift. Also, all the swirl centers are quite apart from the cylinder center so that the effect of eccentricity may not be negligible at 1.75B regardless the valve angle. Related to the tangential velocity along with the radial direction, the bands of the velocity distribution are very wide and the mean velocities of cylinder center basis are lower than the velocity which is assumed in the ISM evaluation. Lastly, the mean tangential velocity profiles of swirl center basis are sometimes higher than that of ISM-assumed up to 0.6 non-dimensional distance less than 6mm lift, however, as the lift increases the profiles are different according to the angles and profile
is the most closed to the ideal profile. Consequently, the real velocity profile is far from the assumption of ISM evaluation.
Characteristic Dynamics Torque Vibration of Behavior in Wet Clutch Engagement for Dual Clutch Transmissions
Cho, Jaecheol ; Kim, Woojung ; Jang, Jaeduk ; Jang, Siyoul ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 183~190
DOI : 10.7467/KSAE.2016.24.2.183
Engine torque is transferred to the transmission where drag torque is minimized improving fuel efficiency. This is particularly true in a wet clutch pack. This study measures slip friction when the wet clutch pack in a DCT (Dual-Clutch Transmission) is disengaged, and the friction pads are slipping. Shudder engagement velocity, and applied forces can be measured under various working conditions through these torque transfer experiments. Test results demonstrate that the design parameters, and engagement conditions of wet clutch packs can be optimized to reduce shudder and frictional vibration during engagement in a dual clutch transmission.
Bumper Stay Design for RCAR Front Low Speed Impact Test
Kang, Sungjong ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 191~197
DOI : 10.7467/KSAE.2016.24.2.191
RCAR low speed impact test estimates repair cost of the impacted vehicle. In this study, for a mid-size vehicle front body model, structural performance for RCAR low speed impact were analyzed with changing the bumper stay shape and size. First, for improving the impact load transfer mechanism to side member the stay rear section shape at connecting area with side member was modified and the stay outer was redesigned to be normal to the barrier. Next, the investigation on stay thickness effect was carried out and the performances of several models with different forming shape were compared. The final design showed 13mm decrease in the maximum barrier intrusion distance and greatly reduced side member deformation. Additional analyses explained the validity of the final design.
An Experimental Study on the Aerodynamic Characteristics of a Streamline-designed High-speed Bus
Kim, Chul-Ho ; Lee, Seung-Hyun ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 198~204
DOI : 10.7467/KSAE.2016.24.2.198
In this study, a wind tunnel test was conducted to measure the aerodynamic characteristics of a streamline-designed high-speed bus with the change of wind direction and speed and the result is compared with the aerodynamic performance of a commercialized high-speed bus model (Model-0) manufactured by Zyle Daewoo Bus Corp. Aerodynamic performance of the existing rear-spoiler was tested to prove its aerodynamic effect on the test model bus. From the study, it was found that 24.6 % of the total drag of the original bus model (Model-0) was reduced on the streamline-designed model bus(model-1) without the rear-spoiler but only 14.3 % of the total drag was reduced with the spoiler on the streamlined model bus. It means that the rear spoiler does not work properly with the streamlined model bus (model-1) and should be noted that an optimum design of a rear-spoiler of a vehicle is important to reduce the induced pressure drag and increase the driving stability of a vehicle against yaw motion. The experimental outcome was also compared to the previous numerical research result to evaluate the reliability of the numerical algorithm of the aerodynamic performance analysis of a vehicle. The error rate (%) of the numerical result to the experimental output is about 5.4 % and it is due to the simplified body configuration of the numerical model bus. The drag increases at the higher yaw angle because the transparent frontal area of the model vehicle increases and the downward force increases with the yaw angle as well. It has a positive effect to the driving stability of the vehicle but the moderated downward force should be kept for the fuel economy of a vehicle.
Comparison of Performance between Symmetric Trapezoidal Fins and Asymmetric Trapezoidal Fins
Kang, Hyungsuk ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 205~213
DOI : 10.7467/KSAE.2016.24.2.205
Heat loss and fin efficiency of symmetric and asymmetric trapezoidal fins with variable slope of fin's top surface are obtained by using a two-dimensional analytic method. Shapes of symmetric and asymmetric fins are changed from rectangular through trapezoidal to triangular by adjusting the fin shape factor. The ratio of symmetric trapezoidal fin length to asymmetric trapezoidal fin length is presented as a function of fin base height and convection characteristic number. The ratio of symmetric trapezoidal fin efficiency to asymmetric trapezoidal fin efficiency is presented as a function of the fin base height and fin shape factor. One of results shows that asymmetric trapezoidal fin length is shorter than symmetric trapezoidal fin length (i.e., asymmetric trapezoidal fin volume is smaller than symmetric trapezoidal fin volume) for the same heat loss when the fin base height and fin shape factor are the same.
Real Time Traffic Signal Recognition Using HSI and YCbCr Color Models and Adaboost Algorithm
Park, Sanghoon ; Lee, Joonwoong ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 214~224
DOI : 10.7467/KSAE.2016.24.2.214
This paper proposes an algorithm to effectively detect the traffic lights and recognize the traffic signals using a monocular camera mounted on the front windshield glass of a vehicle in day time. The algorithm consists of three main parts. The first part is to generate the candidates of a traffic light. After conversion of RGB color model into HSI and YCbCr color spaces, the regions considered as a traffic light are detected. For these regions, edge processing is applied to extract the borders of the traffic light. The second part is to divide the candidates into traffic lights and non-traffic lights using Haar-like features and Adaboost algorithm. The third part is to recognize the signals of the traffic light using a template matching. Experimental results show that the proposed algorithm successfully detects the traffic lights and recognizes the traffic signals in real time in a variety of environments.
Relative Road Damage Analysis with Driving Modes of a Military Vehicle
Suh, Kwonhee ; Song, Bugeun ; Yoon, Hiseak ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 225~231
DOI : 10.7467/KSAE.2016.24.2.225
A military vehicle is driven at different usage modes with the army application and servicing conditions. For practical durability validation, DT(Development Test) on a new military vehicle should be run up to the durability target kilometers on test courses in the specified proving ground. Driving velocities with test courses at the endurance mode of DT are established definitely. However, OT(Operational Test) and initial endurance test of production car can't be performed only in the DT courses due to the development period limit. Therefore, this paper focuses on the method to analyze the relative road damages between the endurance test in DT and other endurance test. Road load acquisition tests on KLTV(Korean Light Tactical Vehicle) were implemented at 15 driving modes in off-road and cross-country courses of two tests. Wheel accelerations were processed through band-pass filter, and then the main frequency and maximum power of the signals were computed by PSD analysis. Finally, using the proving ground optimization based on RDS(Relative Damage Spectrum) characterization, the damage factors between off-roads of test courses were determined.
The Effect of the Embedded WGV on the Engine Performance for a 2-liter Turbo-charged Gasoline Engine
Jang, Jongkwan ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 232~241
DOI : 10.7467/KSAE.2016.24.2.232
The turbocharger, to decrease the harmful exhaust gas(CO, HC and etc.) and
emission as well as the increase of the engine output, would be an useful method for engine downsizing. Therefore the thermal endurance of turbine blade, the lubrication of turbine shaft and the engine knock according to the supercharge of the inlet air, had been studied. And there had been much progress in these research tasks to be achieved a breakthrough. But a study on the built-in WGV of a gasoline engine for a passenger car which may effect on the engine performance, is few. In this paper, the effect of the embedded WGV on the engine performance was performed through the endurance test, which was conducted more than 300 hrs using the 4 stroke, 1998 cc, water-cooled engine. To sum up the major results, there were an abrasion in the area of the WGV head edge and the thermal deformation on the WGV head face, These phenomena led to reducing the boost pressure which caused the reduction in the volumetric efficiency of the engine. It resulted in decreasing the engine power gradually during the life cycle of the embedded WGV.
Study on Evaluation Method of Flow Characteristics in Steady Flow Bench(4) - Velocity Profile(2)
Park, Chanjun ; Sung, Jaeyong ; Ohm, Inyong ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 242~254
DOI : 10.7467/KSAE.2016.24.2.242
This paper is the forth investigation on the evaluation methods of flow characteristics in a steady flow bench. In the previous works, it was concluded that the assumption of the solid rotation might cause serious problems and both of the eccentricity and the velocity profile distort the flow characteristics when using the ISM at 1.75B plane. Also particle image velocimetry (PIV) measurement at this position showed that the real velocity profile was far from the assumption of ISM evaluation. In this paper, the planar velocity profiles were measure from 1.75B to 6.00B position by PIV and the characteristics were examined according to the valve angles and lifts for further investigations about the effect of the position on the velocity profile. The results show that
valve angle is always an unique exceptional case in all aspects. If the valve angle is
and below, the planar velocity profiles according to the lift and the position are similar to each other, however, the tangential velocity curves along with the radial direction have common tendencies up to
angle. Also the well arranged swirl behaviors are generally observed at the position above 3.00B and the velocity contour lines come closer to the concentric circle as the valve lift increases. In addition, the gradient of tangential velocity along with the radial direction from the swirl center becomes stable and constant as the position goes downstream. Concurrently the velocity gradient is larger to the eccentric direction of the center. In the meantime the tangential velocity curves along with the radial direction are irregular and various at 1.75B, however, they become regular and reach higher level as the evaluation position goes downstream. At this time the curves of 4.50B are the best fitted to the ideal one. On the other hand in an exceptional case,
, the velocity contours are very complicated over 6mm valve lift regardless the position and the gradient increases to the opposite direction of the eccentric center. Also, 6.00B is a best fitting position in the geometrical cylinder center base. With respect to the swirl center, the distribution range of centers for 1.75B is different to that for the other positions and the eccentricities of this plane are larger regardless the valve angle. After 1.75B, there is no certain tendency in the center position change according to the valve angle and lift. Additionally, the eccentricities are not sufficiently small to neglecting the effect on ISM measurement.
Road Test Scenario and Performance Assessments of Lane Keeping Assistance System for Passenger Vehicles
Woo, Hyungu ; Yong, Boojoong ; Kim, Kyungjin ; Lim, Jaehwan ;
Transactions of the Korean Society of Automotive Engineers, volume 24, issue 2, 2016, Pages 255~263
DOI : 10.7467/KSAE.2016.24.2.255
Lane Keeping Assistance System (LKAS) is a kind of Advanced Driver Assistance Systems (ADAS) which are developed to automate/ adapt/ enhance vehicle systems for safety and better driving. The main system function of LKAS is to support the driver in keeping the vehicle within the current lane. LKAS acquires information on the position of the vehicle within the lane and, when required, sends commands to actuators to influence the lateral movement of the vehicle. Recently, the vehicles equipped with LKAS are commercially available in a few vehicle-advanced countries and the installation of LKAS increases for safety enhancement. The test procedures for LKAS evaluations are being discussed and developed in the international committees such as ISO (the International Organization for Standardization) and UNECE (United Nations Economic Commission for Europe). In Korea, the evaluations of LKAS for vehicle safety are planned to be introduced in 2016 KNCAP (Korean New Car Assessment Program). Therefore, the test procedures of LKAS suitable for domestic road and traffic conditions, which accommodate international standards, should be developed. In this paper, some bullet points of the test procedures for LKAS are discussed and proposed by extensive researches of previous documents and reports, which are released in public in regard to lateral test procedures including LKAS and Lane Departure Warning System (LDWS). And then, to evaluate the validity of the proposed test procedures, a series of experiments were conducted using commercially available two vehicles equipped with LKAS. Later, it can be helpful to make a draft considering domestic traffic situations for test procedures of LKAS.