• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.149-162
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• 1999

One of the most important steps of the design, capacity and operation analysis stapes in the two-lane two way highways is the effect of heavy vehicle to traffic flow quality. This heavy vehicle's effect on traffic flow can be represented as PCE, which is the number of passenger cars that are displaced by a single heavy vehicle of a particular type under prevailing roadway, traffic, and control conditions. In this paper, we focus on the heavy vehicles effect on volume, speed, delay, and the maneuver of freedom which are major MOE's in traffic operation analysis and PCE criterion which should be measurable, determinable and able to reflect the traffic flow characteristics. Therefore, the objective of the paper is to determine the PCE criterion and to develop a new PCE determination method. In this study, delay is adopted as PCE criterion and, for calculation of delay, the highway is divided into the passing zone and the no-passing zone. PCE is determined by comparing the delay due to total traffic flow interaction with the delay due to a single heavy vehicle, Also, this paper proposes a new method to determine the average PCE on the highway that has the passing zones and no-passing zones.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.79-90
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• 2007

In determining vertical grades in highway alignment design, engineers usually consider heavy vehicle performances on the upgrade. Heavy vehicles usually experience speed reduction on the upgrade and with recent years weight/horsepower improvements for heavy vehicles the speed reduction shows some change. However, in spite of the weight to horsepower improvements for the design vehicles from 300lb/HP to 200lb/HP in the AASHTO, there was no change in the maximum vertical grades. Therefore, a review of the maximum vertical grade reflecting existing heavy vehicle performances is required. In particular, in South Korea where highways pass through lots of mountaineous terrain, the maximum vertical grades must be reviewed throughly. In this study the amount of heavy vehicle performances during past decades were investigated and their expected impacts on highway vertical alignment designs were subsequently analyzed. A worldwide terrain analysis and international design standards were compared to set South Korean vertical grade standards. Traffic flow simulation Vissim was utilized to simulate vehicular flows on the upgrade and new truck performance curves on the grades were developed. Based on the new curve, it was decided that $1{\sim}2%$ increase of the maximum vertical grades could be allowed.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.3
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• pp.73-82
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• 2011

Most of countries start to restrict the emission gases of vehicles especially CO2 because of the global warming. Many vehicle companies including Toyota have launched various HEVs to satisfy the restriction laws and to improve the vehicle's efficiency. However, development for heavy-duty hybrid system is not plentiful rather than the passenger car. In this study, we choose the optimal size of engine, motor and battery for heavy-duty hybrid systems using dynamic programming. Also we analyze the correlation of the system's cost and efficiency because the added cost of vehicle to make the hybrid system is very important factor for the manufacturing companies. Finally, this study suggests a method to choose the appropriate system components size considering its performance and the cost. With this method, it is possible to select the component size for various systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.121-129
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• 2000

this paper develops a computational model for the turning maneuver analysis of a cabover type heavy truck. The model having 42 degree-of-freedom is developed using ADAMS. Leaf springs used in the front and rear suspension systems are modeled by dividing it three links and joining them with joints. Force and displacement relationship showing nonlinear hysteric characteristics of the leaf spring is measured and modeled with an exponential function. A velocity and force relationship of a shock absorber is measured and modeled with a spline function. And a stabilizer bar is modeled using ADAMS beam element to consider a twisting and bending effect. To verify the developed model an actual vehicle test is performed in the double lane change course with 50kph and 60kph vehicle velocity. In the actual vehicle test lateral acceleration roll angle and yaw rate are measured, The tendency and peak-to-peak values of the actual vehicle test and simultion results are compared each other.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.4
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• pp.107-116
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• 1992

The structural integrity of bridges is mainly damaged by overloaded heavy vehicles. The increasing volumes of overloaded heavy vehicles has been indicated as serious state. As results several countries have revised their bridge load codes. However, because of variety of truck types and their weights it is difficult to develop rational standard truck loads. In addition the common practice that only one design configuration of standard truck is adopted to design variety of bridges causes further difficulties. The objective of the study is to investigate the statistical characteristics of vehicle loadings based on survey data collected, in which some major factors, such as vehicle configurations, vehicle weights, traffic modes, etc., are incorporated. The vehicle load effects due to single presence of heavy truck are also tested with several short-span bridges and probabilistic characteristics of current design practices are evaluated.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.307-314
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• 2015

The purpose of this study is know the fuel economy of difference tractive resistance calculation methods on light duty low-floor bus. Two tractive resistance calculation methods(coastdown test and JFCM conversion formula) are tested to understand the difference of fuel economy. JFCM was developed for fuel economy regulations of heavy duty vehicle. That show a big difference as a result of the calculation using coastdown test and JFCM conversion formula. The difference of the tractive resistance affects the fuel economy.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.466-470
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• 1997

This paper forcuses on methods of achieving a direct vector control of induction motors for an electric vehicle based on a closed-loop flux observer. Also over-modulation topology and maximum torque per ampere over the entire field weakening region have been implemented. The proposed scheme is verified through the simulation and the experiment using the chassis dynampmeter and road load driving test for the induction motor controller and the electric vehicle system.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.143-145
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• 2005

This paper describes the transmission method of an information using communication networks between RTU(Remote Terminal Unit) and PCU(Protection and Control System) of the DC switchgear for Light Railway Vehicle. Also the test result carried out in the laboratory was represented. In this test, transmission signal waveform, polling time, response time and request/response frame between RTU and PCU were measured. The field test including the measurements of analog signal and status of the digital logic operation of PCU was conducted in Gyeongsan Test Track.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.1
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• pp.103-110
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• 2017

Most commercial vehicles have adopted the hydraulic power steering system. To reduce fuel consumption and to improve steering controllability, a hybrid electric power steering system is being developed for commercial vehicles. In this study, the HILS (Hardware In the Loop Simulation) system equipped with a commercial vehicle hybrid electric power steering system was developed and the vehicle dynamic performance of a truck with the steering system was evaluated. The hybrid electric power steering system is composed of the EHPS motor pump, column mounted EPS system, and ball nut steering gear box for heavy commercial vehicles. The accuracy of vehicle models equipped with the HILS system was verified with comparisons between the simulation results and field test results. The road reaction forces of the steering system were generated from the vehicle model and verified using field test results. Step steering tests using the verified HILS system were carried out and the performance of a newly developed commercial vehicle hybrid electric power steering system was evaluated.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.45.3-45
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• 2001

This paper deal with a fault detection algorithm for front wheel passenger car systems by using robust $H{\infty}$ control theory. Firstly, we present a unified formulation of vehicle dynamics for front wheel car systems and transform this formulation into state space form. Also, by considering the cornering stiffness which depends on the tyre-road contact conditions, a multiplicative uncertainty for vehicle model is described. Next, the failures of sensor and actuator for vehicle system are defined in which the fault .lter is considered. From the nominal vehicle model, an augmented system includes the multiplicative uncertainty and the model of fault filter is proposed. Lastly by using $H{\infty}$ norm property the fault detect conditions are deefi.ned, and the actuator and sensor failures are detected and isolated by designing the robust $H{\infty}$ controller, respectively.