• 한국자동차공학회논문집
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• 제19권2호
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• pp.142-147
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• 2011

Compressed natural gas (CNG) is well known as one of the cleanest burning alternative fuels. Bi-fuel CNG vehicle can also run on gasoline or another fuel while dedicated natural gas vehicle is designed to run on natural gas only. Recently, increased attention has been focused on bi-fuel CNG/LPG taxi because of good fuel economy of CNG. A number of LPG taxis modified to CNG Bi-fuel vehicles are running in many cities. In this paper, the emissions characteristics of in-use passenger cars running on CNG and LPG were investigated. Chassis dynamometer test was used to measure exhaust emissions from an in-use fleet of 5 cars. Exhaust emissions were collected for CVS-75 driving mode. The test results showed that for CNG fuel mode, CO, $CO_2$ and NMHC emissions decreased to 9%, 12% and 14% respectively, and $CH_4$ and $NO_x$ emissions increased to 317% and 47% respectively.

• 오토저널
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• 제13권3호
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• pp.49-57
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• 1991

Natural gas is one of the most promising alternative fuels for automative vehicles, because it has lower exhaust emissions and better fuel economy characteristics than gasoline and can be used in conventional engines with a little modification. In the present study, a conventional gasoline engine was modified to a CNG dedicated engine, which can be operated with CNG( compressed natural gas) only, and a engine bench test was performed at various compression ratios. As a result, it was revealed that the prototype CNG engine can be operated with lower exhaust emissions, better fuel economy and better thermal efficiency, but with a sightly reduced brake horse power, compared to the conventional gasoline engine.

• 대한기계학회논문집A
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• 제35권4호
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• pp.439-445
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• 2011

대기오염 등 환경에 대한 관심이 높아지면서 경유차 배출 가스 저감을 위한 최적의 대안으로 최근 세계적으로 천연가스차량의 보급이 크게 확대되고 있는 추세이다. 이러한 추세에도 불구하고 그 안전성에 대해서는 많은 논란을 불러 일으키고 있으며 최근 그 이용에 따른 안전사고 또한 빈번하게 발생하고 있다. 천연가스버스 압력용기 파열 사고는 대중들이 많이 이용한다는 점에서 대형참사로 이어질 수 있는 잠재력을 가지고 있어 그 심각성은 매우 크다고 할 수 있다. 이에 법공학적인 측면에서 좀 더 전문화되고 체계적인 사고조사와 원인 규명을 통해서 사전에 예방대책을 마련함으로써 유사 및 동종재해의 발생을 최소화해야 한다. 본 연구에서는 구조해석을 통한 용기의 설계 검증과 용기의 파손형태 검사 및 재료 물성평가 등을 통해 용기파손에 의한 CNG 차량 폭발 사고에 관한 정확한 사고 원인을 규명함으로써 동일 형태의 차량 안전사고 예방에 기여하고자 한다.

• 청정기술
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• 제24권3호
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• pp.166-174
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• 2018

인체의 건강뿐만 아니라 일상 활동에도 막대한 악영향을 끼치고 있는 미세먼지를 저감하기 위하여 경유자동차의 엔진에 압축천연가스(CNG)와 경유를 함께 사용할 수 있도록 하는 혼소시스템이 개발되고 있다. 본 연구에서는 CNG와 경유를 함께 사용하는 혼소시스템을 경유버스에 적용하였을 때 얻을 수 있는 경제적 비용과 편익을 실제 주행결과를 바탕으로 평가 분석하여 혼소시스템의 경제적 타당성을 검토하였다. 혼소버스의 연간 주행거리가 30,000 km 이상이거나 경유와 CNG의 연료단가 차이가 408원 이상일 때 혼소시스템의 경제성이 확보되는 것으로 나타났다. 경제성 평가의 불확도평가 결과에서는 주행거리와 연료단가 등 입력 데이터의 변동성에 대해서도 경제성이 확보될 수 있는 확률이 매우 높았다. 민감도분석 결과에서는 혼소시스템의 경제적 타당성에 가장 큰 영향을 미치는 인자는 경유 연료단가로 나타났다. 이러한 결과를 바탕으로 혼소시스템의 보급을 늘리기 위한 경제적 유인책이 분석되었다. 본 연구결과는 경유 버스에서 발생하는 미세먼지 문제를 저감하기 위한 혼소시스템의 보급을 확대시키기 위한 정책적 방안을 개발하는데 기여할 수 있을 것이다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.911-915
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• 2007

This paper deal with the design concept of traction motor for Bimodal low floor vehicles that are CNG(Compressed Natural Gas) hybrid bus and Fuel-cell bus. The design concept of the traction motor is studied in terms of electrical characteristics and mechanical construction. Finally, this paper introduces the characteristic of the traction motor for low floor vehicles which are applied in the world, and mentioned the detail design concept of traction motor.

• 한국기계가공학회지
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• 제16권4호
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• pp.97-103
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• 2017

The objective of this study is to develop and commercialize an on-board fuel storage system for CNG vehicles. A type 4 vessel is made of resin-impregnated continuous filament windings on a polyamide (PA6) liner. In particular, this study localized the PA6 liner's fabrication and development. To analyze the filament winding, a specimen test was performed, and the results were verified values obtained using finite element analysis. In this study, the filament winding and fibers were optimized for a 207 bar composite cylinder in a compressed natural gas vehicle.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.7-17
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• 2003

Highly accurate control of an air-fuel ratio is very important to reduce exhaust gas emissions of gaseous-fuel engines. In order to achieve this purpose, a precise engine model is required to estimate engine performance from the engine design process which is applied to the design of an engine controller. Engine dynamics are considered to develop a dynamic engine model of a gaseous-fuel engine. An effective air mass ratio is proposed to study variations of the engine dynamics according to the water vapor and the gaseous-fuel in the mixture. The dynamic engine model is validated with the LPG engine under steady and transient operating conditions. The experimental results in the LPG gaseous-fuel engine show that the estimation of the air flow and the air-fuel ratio based upon the effective air mass ratio is more accurate than that of a normal engine model.

• 한국해양공학회지
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• 제27권1호
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• pp.51-58
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• 2013

Recently, there has been an increase in the demand for natural gas as a source of clean energy, which has increased the demand for LNG carriers. However, LNG carriers require a capital investment to obtain equipment for the regasification process, which prevents fires and explosions. Thus, on account of NIMBY, a CNG carrier is suggested that eliminates the need for regasification equipment. Meanwhile, carbon dioxide emissions are more and more regulated by international conventions such as the Kyoto Protocol. Because of this, $CO_2$ carriers have also received international attention as a methodology to transport and store $CO_2$ cargoes. Several vessels or tanks to transport and store $CO_2$ gas have been studied in various countries. This paper proposes a conceptual design for a 20ft container shaped tank to effectively transport small cargoes of $CO_2$ and CNG. The proposed pressure vessel or tank will be carried by a conventional containership or special cargo ship. The influences of the design parameters for proposed pressure vessel or tank. Including the materials, scantlings, and shape of the pressure vessel, are studied theoretically and computationally.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.145-151
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• 2005

Natural gas is one of clean fuels that can replace petroleum-based fuels, because it has low exhaust emission, comparatively high thermal efficiency and abundant deposits. In this addition, owing to high octane number and wide lean flammability limit, it has a strong point to increase the compression ratio. For this reason, the research is being actively executed to increase the generating power and thermal efficiency of the engine by raising the compression ratio through utilization of high octane number relevant to development of CNG engine. In this study, 0.63L single cylinder diesel engine has been used to alter easily compression ratio. Compression ratio has gotten under control by modifying the thickness of gasket between cylinder head and block without major structural modifications. As the result, as compression ratio has increased, generating power and fuel consumption ratio have been improved. As for emission concentration, as compression ratio has increased, THC concentration has been decreased while exhause concentration of NOx increased. In case compression ratio has excessively increased, brake output decrease and cycle variation have been increased. As the result acquired by analyzing brake output, fuel consumption ratio, cycle variation and exhaust, the engine driving condition has acquired $\varepsilon=13$ as the optimal compression ratio in this study.

• 대한기계학회논문집B
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• 제37권12호
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• pp.1129-1135
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• 2013

본 연구에서는 저발열량 천연가스가 현재 상용되고 있는 대형 천연가스 엔진에 미치는 영향을 살펴보기 위하여 3종류의 연료를 적용하였다. 전부하 운전조건과 WHSC 및 WHTC 모드 테스트를 수행하여 엔진성능 및 배기특성을 분석하였다. 실험결과 전부하 실험에서 토크성능이 $9,800kcal/Nm^3$의 발열량을 갖는 저발열량 가스의 경우 현행 천연가스($10,400kcal/Nm^3$)를 사용한 결과에 비해 4.4% 감소하였다. 저발열량 연료를 사용하였을 때 일산화탄소, 이산화탄소 및 질소산화물의 배출량은 감소하였지만, 탄화수소의 배출량은 증가하였다. WHSC 및 WHTC 실험결과 저발열량 연료에서 열효율이 증가하였으며 배기특성은 전부하 실험결과와 유사한 경향을 보였다. 저발열량 천연가스를 사용할 경우 제원상의 출력을 만족하기 어렵고, 탄화수소의 배출이 증가하는 문제점을 확인하였다.