• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3335-3340
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• 2007

The government have been tightening EM regulation gradually but the effect is not good because of rapid increase of vehicles. And medium & heavy duty diesel vehicles, even though the number is small, exhaust very large pollutants(about over 50%). Especially it is more severe about old trucks and buses. Accordingly, CNG vehicle and the retrofit of diesel to CNG must be an alternative in order to protect the atmospheric environment and improve the air quality in the metropolitan area. The main object of this study is to secure the retrofit technology of diesel to CNG vehicle and the management system of CNG engine. we passed the government emission certification test. In addition to this, the mass production for retrofit is also studied. Results of emission and durability test for certification are as follows; there was no problem during 30,000km vehicle durability test and good emission levels satisfying the regulation.

• 한국자동차공학회논문집
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• 제16권6호
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• pp.104-108
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• 2008

Recently, studies conducted by our research group, revealed the possibility for reducing BSFC, NOx and PM emissions to meet the Euro 4 & 5 legislations. The main objective of the present study is to get better fuel economy in commercial vehicles by considering real driving conditions. Firstly, in order to improve fuel economy on fields, specifically it is required to analyze the driving pattern and make the representative modes from real field data. Secondly, it is performed to make the engine dynometer test to optimize the fuel consumption by reflecting on the representative driving modes, based on the Korea 2008 emission legislation equal to the Euro 4. The engine components such as engine calibration, combustion chamber, turbocharger and ancilliaries were modified to optimize vehicle fuel economy over a typical customer drive cycle whilst still meeting the exhaust emission restrictions. Finally, these results were confirmed by field testing of vehicle equipped with the updated calibration engine. It was placed the two vehicles together traveling the same route and accomplishing the same amount of stops(back to back), in order to evaluate the fuel consumption in comparison to the current vehicle. Through several repeats such as the engine calibration and field test, we could get 3 % to 7.7 % vehicle fuel economy improvements compared to previous vehicle.

• 산업공학
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• 제25권1호
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• pp.134-141
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• 2012

The steering gear box for mid-heavy duty electric vehicles are usually produced by only a few specialized companies. The special techniques, such as designing, producing and testing technology have been veiled. For this reason, steering gear boxes are imported from other country. The durability test with the electric vehicle which is satisfies the design parameters takes several years, and a prototype is installed in the real vehicle for the test. In this research, the steering gear box of the steering system was developed based on the reverse engineering and the testing methods and the steering gear box development process have been suggested. The prototype is also developed with the CAD and CAE tools. Developed steering gear box have been tested in torque tester and have satisfied requied torque. As a result, the process and testing methods studied in this research are useful in the development processes of electric vehicles steering system.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.181-189
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• 2000

The aerodynamic characteristics of large transport vehicle has become more and more important in recent vehicle design to improve driving performance in high speed cruising and raise the product valve with regard to a comfortable driving condition. Hence, detailed knowledge of the flow field around truck coner vane is essential to improve fuel efficiency and reduce the dirt contamination on vehicle body surface. In this study, three-dimensional flow characteristics around corner vane attached to truck cabin were computed for the steady, incompressible, and high speed viscous flow, adopting the RNG k-$\varepsilon$ turbulence model. In order to investigate the influence of configuration and structure of corner vane, computations were carried out for four cases at a high Reynolds number, Re=4.1$\times$106 (based on the cabin height). The global flow patterns, drag coefficient and the distributions such as velocity magnitude, turbulent kinetic energy around the corner vane, were examined. As a result of this study, we could identify the flow characteristics around corner vane for the variation of corner vane length and width. Also, suggest the improved structure to reduce the dirt contamination in cabin side.

• 공업화학전망
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• 제24권4호
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• pp.22-35
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• 2021

현재 수소전기차는 승용 및 상용 등 다양한 모빌리티 분야에서 전 세계적으로 이슈가 되고 있다. 환경규제 강화, 신기후체제 출범 등의 변화의 물결에 따라 자동차산업의 패러다임이 친환경으로 전환되고 있으며, 세계적으로 관련 기술 개발 및 보급을 위한 확대 정책이 발표되고 있다. 1990년 초 수소전기차(Fuel Cell Electric Vehicle, FCEV) 기술 개발이 진행되어 1994년 독일 다임러사가 세계 최초로 NECAR1을 개발하였다. 이후 많은 완성차가 상용화를 위해 기술개발이 진행되었으며, 2013년 국내 현대차가 세계최초로 양산차인 투싼 ix 수소전기차를 출시하였다. 1년 이후 다시 일본 도요타에서 세계 최초로 전용 차체를 적용한 미라이 수소전기차가 출시되면서 초기시장이 형성되었으며, 이후 현대차는 NEXO를 2018년에 발표하였다. 전 세계적으로 가장 많이 팔린 수소전기차에 해당된다. 2021년 미라이 2세대가 더욱 진보된 기술을 바탕으로 출시되었으며, 국내 현대차에서도 2세대 수소전기차 출시를 앞두고 있다. 또한 수소승용차 뿐만 아니라 수소상용차 시장이 뜨겁게 부각되고 있으며, 각국에서 수소상용차 기술개발을 진행하고 있다. 본 기획특집에서는 각국의 수소전기차 기술개발 및 보급 정책을 소개하고 국내 기술개발 및 보급 정책의 타당성을 확인하고자 하였다.

• 융복합기술연구소 논문집
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• 제11권1호
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• pp.19-23
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• 2021

These days, sales of battery electric vehicles have been rapidly increasing due to the strict CO₂ regulations. However, since it take too long to measure the energy economy of electric vehicles, it has been required to improve the procedure of energy economy measurement. In order to improve this problem, the present study analyzed the battery charge/discharge pattern according to the changes in battery SOC (state of charge). In general, the energy economy test is started with a battery SOC charged to 100 %. However, it was identified that when the battery is fully charged, it can actually be charged over the 100 % (e.g., 100.5 %). This can induce errors in the energy economy measurement. Therefore, the present study recommend to start the test at SOC 99.9 %. The regenerative braking was partly restricted for the SOC over 90 %. This made it difficult to estimate the overall energy economy of the electric vehicle. However, it was identified that there was no change in the battery charge/discharge characteristics under the SOC 90 %. Therefore, the energy economy test can be shortened by predicting the overall energy economy through a short mileage test.

• Environmental Engineering Research
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• 제20권4호
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• pp.397-402
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• 2015

SCR has been popularly approved as one of the most effective means for NOx emission control in heavy-duty and medium-duty vehicles currently. However, high urea dosing would lead to ammonia slip. And $NH_3$ sensor for vehicle emission applications has not been popularly used in real applications. This paper presents experimental studies on the diesel engine urea-SCR system by using a double NOx sensor system that is arranged in the downstream of the SCR catalyst based on ammonia cross-sensitivity. It was shown that the NOx conversion efficiency rised as $NH_3/NOx$ increases and the ammonia slip started from the $NH_3/NOx$ equal to 1.4. The increase of temperature caused high improvement of the SCR reaction rate while the space velocity had no obvious change. The ammonia slip was in advance as catalyst temperature or space velocity increase and the ammonia storage reduced as catalyst temperature or space velocity increase. The NOx real-time conversion efficiency rised as the ammonia accumulative storage increase and reached the maximum value gradually.

• 한국산학기술학회논문지
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• 제10권9호
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• pp.2210-2220
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• 2009

대형 특수차량용 독립현가형 액슬은 극소수 전문업체에서 생산되며 설계, 제작, 시험평가 등 세부기술은 제공되지 않고 있다. 또한 액슬 제작을 위한 설계기준 설정에는 시작품을 실제 차량에 탑재하여 수년 이상 소요되는 내구성 시험이 필수적이다. 본 연구는 독립현가형 액슬의 핵심부품인 스루드라이브를 역설계방법으로 개발하였으며 개발목표 달성 확인에 필요한 시험평가기준을 제안하였다. 또한 CAD/CAE 도구를 사용하여 제품을 설계하고 설계검증을 거쳐 시제품을 제작하였다. 본 연구에 적용된 개발절차 및 방법은 차량의 동력전달계통 개발에 유용할 것이다.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.1-7
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• 2013

This paper focuses on cooling fan control by using a magnetic clutch type for the improvement of fuel economy on a heavy city bus. In general, Heavy duty vehicles use viscous clutch type cooling fan which has some disadvantages, such as slow response, wide temperature variation of engine coolant water. But a magnetic clutch type cooling fan can be controlled electronically so the engine coolant temperature can be precisely controllable and this effects could be used to reduce fuel consumption. A control system for applying the magnetic clutch type cooling fan was developed in this study and applied to the real field test and chassis dynamometer test. The result showed well controlled coolant temperature and enhancement of fuel economy.

• 한국공작기계학회논문집
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• 제16권3호
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• pp.56-63
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• 2007

Modern diesel vehicle has to comply with the EURO IV, V regulation with low level of particulate matter and smoke emission Moreover, emission standards of each countries are becoming stringent in advanced countries such as USA and Europe. Because Bio-diesel is similar to diesel fuel, it is essential to judge the environmental and health effects deriving from the use of Bio-diesel in diesel engine. The deterioration characteristics of emission in accordance with aging vehicles must be regulated for Bio-diesel. Therefore, under 1200 driving hours, 220,000km driving distance condition and full load, the deterioration characteristics of emission were estimated. We could reduce sulfur contents of fuel, particulate matter and smoke emission by using Bio-diesel and conform the influence of engine performance, emission, and fuel consumption by Bio-diesel deterioration