• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.3
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• pp.154-161
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• 2005

The durability of a vehicle is a very important performance which can be evaluated from endurance test. This study developed a procedure for determination of a duty cycle theoretically. Vehicle load data is classified and rearranged using standard test road profile. A load pattern and a duty cycles are extracted from classified vehicle data using genetic algorithm. A duty cycle could be utilized in dynamo test to meet required test mileage. The derived duty cycles have been verified by fatigue test through the dynamometer test.

• Clean Technology
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• v.24 no.3
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• pp.166-174
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• 2018

Since particulate matter has high impacts on human health and everyday life, the dual fuel systems utilizing diesel and compressed natural gas have been developed to improve the environmental performance of diesel vehicles. The objective of this study is to estimate the economic feasibility of the dual fuel system based on real operating data of dual fuel buses and diesel buses. The system is economically feasible if the annual mileage of the dual bus is higher than 30,000 km, or if the unit fuel price of diesel is higher than that of CNG by 408 won. The uncertainty analysis results show that the economic feasibility of the system is probabilistically high, regardless of the variability of input data such as mileage and unit prices for the fuels. The sensitivity analysis results show that diesel and CNG prices are the highest contributor to the net present value of the system. Based on these results, economic incentives are suggested to disseminate the systems. This study would provide valuable economic information for bus business industry and policy maker to help make decisions for applying and disseminating the dual fuel systems to mitigate particulate matter problems.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.407-413
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• 2006

The liquefied petroleum gas(LPG), mixture of propane and butane, has the potential to reduce toxic hydrocarbon emissions and inhibit ozone formation due to its chemical composition. Conventional mixer systems, however, have problems in meeting the future lower emission standards because of the difficulty in controlling air-fuel ratio precisely according to mileage tar accumulation. Liquid Phase LPG injection(LPLi) system has several advantages in more precise fuel metering and higher engine performance than those of the conventional mixer type. On the other hands, leakage problem of LPLi system at the injector tip is a main obstacle for meeting more stringent future emission regulations because these phenomena might cause excessive amount of THC emission during cold and hot restart phase. The main focus of this paper is the development of a leaked fuel recirculation system, which can eliminate the leaked fuel at the intake system with the activated carbon canister. Leaked fuel level was evaluated by using a fast response THC analyzer and gas chromatography. The result shows that THC concentration during cold and hot restart stage decreases by over 60%, and recirculation system is an effective method to meet the SULEV standard of the LPLi engine.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.649-659
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• 2016

This paper describes control algorithm and control structure of vehicle control unit for range-extended electric vehicle equipped with engine-generator system, and specially presents methods which determine optimal operating points and decreases a vibration or a shock for operating the engine-generating system. The vehicle control algorithm is consisted of several parts which are sequence control, calculation of wheel demand torque, determination of operating points, and management of operating points and so vehicle controller has be made possible to efficiently manage calibration parameters. The control algorithm is evaluated by driving test modes, launching performance and operating engine-generator system and so on. In conclusion, this paper present methods for extending a mileage, improving a launching performance and reducing vibration or shock when the engine-generating system is starting or is stopping.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.666-672
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• 2008

Train wheels are the most important part of the high-speed rail system with supporting body, running stably and safely. Wheel exchange and fix plan is computed by the worker who managing entire Train Maintenance Process based on his know-how so that this system is losing its reliability and accuracy. And predicting of the wheel's lifetime is absolutely difficult matter because of uncertainty between trains like mileage of the type of trains, condition of operation, curve section and wheel's cutting pattern. Therefore workers always used to hold many wheels. For this reason, the cost of stock is soar when the level of stock was normal. If the stock is sufficient, the cost of stock will rise. On the other hand, If the stock is deficient, we would have trouble that the plan of the train maintenance process will be failed. Thus this paper aimed at application that "Wheel Managing System" which is able to predict wheel's life-cycle and demands under the RIMS(Rolling-Stock Information Maintenance System) with analysing wheel exchanging and cutting status considering economical or stable aspects.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1423-1426
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• 2001

차세대 이동통신 서비스인 IMT2000에서 기본적으로 탑재될 예정인 USIM 카드는 스마트 카드의 또 다른 이름으로서 보다 더 안전하고 다양한 기능을 수행할 수 있다. 본 논문에서는 USIM 카드의 유효성을 입증하기 위하여, 쇼핑몰 마일리지 통합 관리 어플리케이션을 제안한다. 마일리지 통합 관리 어플리케이션은 USIM 카드의 메모리에 저장되어, 한 개인의 독립적인 프로그램으로서 작동되며, 적립된 마일리지의 현금화를 가능하게 한다. USIM 카드의 연산 기능을 이용하여, 각기 다른 마일리지 체계를 가지는 여러 쇼핑몰들간의 통합 마일리지를 직접 계산하고 적립할 수 있는 프로그램을 제안하였다. 본 시스템의 핵심은, 공인기관의 디렉토리를 참조하여 USIM 카드로 서베이 한다는 점이다.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.1
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• pp.25-31
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• 2003

There are a lot of factors influencing on the automobile fuel economy such as average speed, average acceleration, acceleration sum per kilometer, and so on. In this study, various driving data were recorded during road tests. The accumulated road test mileage in Seoul metropolitan area is around 1,300 kilometers. The data were analyzed by multivariate statistical techniques including correlation analysis, principal component analysis, and multiple linear regression analysis. The analyzed results show that the average trip time per kilometer is one of the most important factors to fuel consumption and the increase of the average speed is desirable for reducing emissions and fuel consumption.

• Journal of the Korean Society for Railway
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• v.8 no.5
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• pp.477-482
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• 2005

Through a year's commercial operation, Korea High Speed Railway has solved defectives from several breakages at the beginning and is going into the stage of stable operation. Among issues, wheel wear becomes a matter of primary concerns in view of vehicle's stability and maintenance. It was understood as above that wear status has been improved in the test by which railway system including vehicles and tracks was stabilized during a year's commercial operation, comparing to that with excessive wear in the trial operation prior to opening to the public. To make out wheel's wear status and characteristics of equivalent conicity at present when the service has been introduced a year ago and the average cumulative mileage of vehicles reach almost 500,000km, wheel's wear types were analyzed with the current vehicles in service.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.415-420
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• 2005

Korea High Speed Railway of which wheels have been excessively worn during the trial operation prior to opening was additionally applied with solid lubricant besides the existing oil lubricant in order to overcome such excessive wear. Therefore, it was shown that wear status has been improved in the test by which railway system including vehicles and tracks was stabilized during a year's commercial operation, comparing to that with excessive wear in the trial operation prior to opening to the public. In this connection, wheel's wear per mileage was analyzed, based on vehicles in service in order to make out the wheel's wear at present, from which the useful data relating to wheel maintenance could be obtained.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.214-216
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• 2001

인터넷과 전자상거래가 활성화됨에 따라 인터넷상에서의 보다 안전하고 다양한 기능을 수행할 수 있는 지불수단이 필요하게 되었다. 스마트 카드는 안전성과 이동성이 뛰어나기 때문에, 전자상거래상의 일들을 수행하기에 적합하다. 특히, 스마트 카드의 차세대 COS로 주목받는 Java Card는 어플리케이션의 개발의 용이성과, 뛰어난 독립성을 제공하므로, 효율적인 개발을 할 수 있다. 본 논문에서는 지불에 관련된 쇼핑몰 마일리지 통합 관리 시스템의 개발을 제안함으로써 다양한 로열티 서비스 제공에 대하여 연구하였다. 제안된 시스템은 Java Card 내에 저장되는 한 개인의 독립적인 프로그램으로서, Java Card의 연산기능을 이용하여 서로 다른 마일리지 체계를 가지는 이종 쇼핑몰간의 통합마일리지를 직접 계산하고, 적립할 수 있는 카드 어플리케이션을 제안하였다.