• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.1
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• pp.53-60
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• 2012

As enforced by the regulation on the improving fuel efficiency and increased the demand on green technology, many interests are focused on electric vehicles and hybrid vehicles. Thus the technology development in electrification of vehicle operation system, including steering and braking field, is actively progressive. Especially electric power steering substitutes for hydraulic power steering rapidly in the market, which is more complex and bigger in packaging volume compared with electric power steering system. The core component in electric power steering system is a motor, which is required to be silent and powerful to guarantee required system performance. Brushless synchronous motors are widely used and many variations of the motors are introduced in the market, while the performance of each type is not well defined or studied for electric power steering system. In this paper, recent developments in brushless synchronous motor are reviewed and compared applying finite element analysis in electromagnetic field. As results, each characteristic of different types of brushless synchronous motors is compared and summarized for optimized selection in electric power steering system.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.166-173
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• 2013

An aluminum suspension corner module is widely used in high class passenger cars to reduce vehicle weight and improve fuel economy. According to the change of material and suspension type, the evaluation of the static strength and failure mode of the corner module is important. In this study, static strength and failure mode analysis of aluminium multi-link suspension corner module is presented. Static strength test system is designed and static failure mode tests of the corner module are carried out in longitudinal, lateral, and vertical direction. From the resuls of the tests we found that the failure modes are different compare to those of the steel corner module. The static failure modes and load-displacement curves of this study will be used as a guidance in design of a passenger car aluminium multi-link suspension corner module.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.2
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• pp.165-172
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• 2014

This study was focused on the investigation of the liquid propellants for the launch vehicle, past, present and future trends in worldwide. In general, storable and hypergolic propellants are used for the military purposes and comparing to this, the kerosine fuel and cryogenic propellants are used for the launching systems. Although liquid propulsion is seemed as a mature technology, the requirements of a renewed interest for space exploration has led to the development of a family of new engines, with more design margins, simpler to use and to produce associated with a wide variety of thrust and life requirements.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.244-254
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• 2002

To enhance the acceleration performance and fuel consumption rate of a vehicle, the torque converter is modified or newly-developed with reliable analysis model. Up to recently, the one dimensional performance model has been used for the analysis and design of torque converter. The model is described with constant parameters based on the concept of mean flow path. When it is used in practice, some experiential correction factors are needed to minimize tole estimated error. These factors have poor physical meaning and cannot be applied confidently to the other specification of torque converter. In this study, the detail dynamic model of torque converter is presented to establish the physical meaning of correction factors. To verify the validity of model, performance test was carried out with various input speed and oil temperature. The effect of oil temperature on the performance is analysed, and it is applied to the dynamic model. And, to obtain the internal flow pattern of torque converter, CFD(Computational Fluid Dyanmics) analysis is carried out on three-dimensional turbulent flow. Correction factors are determined from the internal flow pattern, and their variation is presented with the speed ratio of torque converter. Finally, the sensitivity of correction factors to the speed ratio is studied for the case of changing capacity factor with maintaining torque ratio.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.591-598
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• 2005

A three-way catalyst system of a natural gas vehicle (NGV) has characteristics of higher fuel consumption and higher thermal load than a lean-bum catalyst system. To meet stringent emission standards in the future, NGV with the lean-bum engine may need a catalyst system to reduce the amounts of HC, CO and NOx emission, although natural gas system has low emission characteristics. We conducted experiments to evaluate the conversion efficiency of the NOx reduction catalyst for the lean-burn natural gas engine. The NOx reduction catalysts were prepared with the ${\gamma}-Al_{2}O_3$ washcoat including Ba based on Pt, Pd and Rh precious metal. In the experiments, effective parameters were space velocity, spike duration of the rich condition, and the temperature of flowing model gas. From the results of the experiments, we found that the temperature for maximum NOx reduction was around $450^{\circ}C$, and the space velocity for optimum NOx reduction was around $30,000\;h^{-1}$ And we developed an evaluation model of the NOx reduction catalyst to evaluate the conversion performance of each other catalysts.

• Journal of the korean Society of Automotive Engineers
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• v.7 no.3
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• pp.30-35
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• 1985

자동차가 처음 만들어진 당시에는 목적지까지 무사히 도착하는 신뢰성이 중요한 과제가 되었으리 라 생각된다. 무사히 도착되니 다음은 어떻게 하면 빨리 도착할 수 있을까하는 요구에서 고속화 즉 기관의 고출력화가 이루어졌다. 자동차의 편리함이 인식되고 또 보급됨에 따라 자동차가 주 위한경에 미치는 영향이 문제가 되어 1960년대 후반부터 자동차배출가스규제가 시작되고 이어서 소음규제가 실시되어 점차 강화되고 있다. 1973년부터 시작된 석유위기이래 자동차의 석유사용 량을 저감시키는 목적으로 미국에서는 연비규제가 실시되기에 이르렀고 다른 국가들도 거기에 따르고 있다. 미국의 1975년 에너지정책, 보존법(Energy Policy and Conservation Act of 1975 )은 1974년의 평균연비 14mile/gallon을 1985년까지는 약 2배의 27.5mile/gallon까지 높이고자 하는 것이다. 가까운 일본에서도 약 35%정도 향상되고 있는 실정이다. 자동차의 저연비특성은 제품기능으로 점차 중요시되는 동시에 국가차원에서는 석유에너지절약의 한 방편으로 사회적으 로도 해결하여야할 입장에 이르렀다. 이 에너지 절약 문제는 자동차의 소형화를 포함한 국제 적인 자동차 재개발문제로 발전, 80년대의 신기술개발의 최대과제가 되고 있다. 또 최근의 사용 자의 요구는 운전성, 실용성에 대해서도 까다롭고 또 다양화하고 있다. 이들 요구와 엄격한 배 출가스규제 및 소용규제를 만족시키면서 연비저감을 꾀하느것인 만큼 실로 어려운 일임에는 틀 림없다. 여기서는 가솔린기관 승용차의 연비저감을 중심으로 규제의 상황, 연비의 향상기술에 대해서 논하고자 한다.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.759-762
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• 2005

Recently, Intelligent Transportation System(ITS) has been applied to satisfy increasing traffic demand every year and to solve many traffic problems. Especially, Advanced Traveller Information System(ATIS) is a transportation system to optimize the trip of each other vehicle. It is important to provide the driver with quick and comfortable path from source to destination. However, it is difficult to provide a shortest path in a road network with dynamic cost. Because the existing research has a static cost. Therefore, in this paper we propose an operator for searching traffic dependent shortest path. The proposed operator finds the shortest path from source to destination using a current time cost and a difference cost of past time cost. Such a method can be applied to the road status with time. Also, we can expect a predicted arrival time as well as the shortest path from source to destination. It can be applied to efficiently application service as ITS and have the advantages of using the road efficiently, reducing the distribution cost, preparing an emergency quickly, reducing the trip time, and reducing an environmental pollution owing to the saving the fuel.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.11
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• pp.912-917
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• 2001

In this study, we define the measuring method of crank angle precisely using an event and perform a study on the hardware structure and software algorithms which is applicable for the commercial engine. Also we developed a Computer-ECU(Personal computer based electronic control unit) using a computer and a microprocessor, for performing the ignition at a desire position(angle) and for controlling a duty ratio a pulse for ISC(Idle speed control). We applied these algorithms to the modeling which is induced a concept of event and got a better result than a conventional ECU in the state of transient as a result of performing air fuel ratio control in a commercial engine. This technique can be used for the back to improve ECU performance. It the present type of Hybrid I. C voltage regulator is altered to the new type of regulator, we will be surely able to reduce the production cost as well as simplify the design of alternator\`s rear bracket and rectifier part because of the removal of trio diode. Experiment is taken by MS-R004.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.857_858
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• 2009

On account of small size and light weight, a high-speed machine is regarded as a key technology for many future applications of drive systems. In high-speed applications, permanent magnet (PM) synchronous motors have a number of merits such as high efficiency and high power density. Accordingly, they are suitable for driving the air-blower of a fuel cell electric vehicle (FCEV) where space and energy savings are critical. Particularly, a surface-mounted PM motor of them is mainly used as a high-speed machine. However, the motor has a fatal flaw owing to a retaining can to maintain the mechanical integrity of a rotor assembly. The can results in the increase of magnetic air-gap length in the surface-mounted PM motor. Thus, in this paper, an interior PM motor is designed in order to drive the air-blower of FCEV instead of the surface-mounted PM motor, and the experimental results of two models are compared to verify the capability of the interior PM motor for a high-speed machine.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1322-1327
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• 2007

Many automotive companies have tried to apply the aluminum alloy sheet to car body because reducing the car weight can improve the fuel efficiency of vehicle. In order to do that, sheet materials require of weldablity, formability, productivity and so on. Aluminum alloy was not easy to join these metals due to its material properties. Thus, the laser is good heat source for aluminum alloy welding because of its high heat intensity. However, the welding quality was not good by porosity, underfill, and magnesium loss in welded metal for AA5182 aluminum alloy. In this study, Nd:YAG laser welding of AA 5182 with filler wire AA 5356 was carried out to overcome this problem. The weldability of AA5182 laser welding with AA5356 filler wire was investigated in terms of tensile strength and Erichsen ratio. For full penetration, mechanical properties were improved by filler wire. In order to optimize the process parameters, model to estimate tensile strength by artificial neural network was developed and fitness function was defined in consideration of weldability and productivity. Genetic algorithm was used to search the optimal point of laser power, welding speed, and wire feed rate.