• 한국자동차공학회논문집
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• 제3권2호
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• pp.95-101
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• 1995

Experiments have been conducted to investigate the characteristics of formaldehyde and nitrous oxide formation from the catalytic reaction of methane. Catalysts used in the experiment were Pd. Pd/Pt/Rh loaded on ${\gamma}-Al_2O_3$ and ${\gamma}-Al_2O_3-La_2O_3$ monolith. In the catalytic reaction of methane. as the concentration of NO, $O_2$ and $CH_4$ increased, the formaldehyde emission was increased. The concentration of $N_2O$ increased as NO and CO increased. It was also found that the formaldehyde emission was produced by the gas reaction of methane in high temperature above 950K.

• 산업기술연구
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• 제27권B호
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• pp.65-70
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• 2007

The LNG tank are properly designed to fit with the limited installation space of a light duty truck, Hyundai Porter II. This designed LNG tank has 36 liter capacity, so two LNG tanks installed on Porter II truck allow it to run about 432 km per fueling. It is almost two times greater than CNG mileage for same truck. To analyze the relationship between car acceleration and heat leak for different fuel vapor/liquid ratios, the modified Fortran program "Pro-Heatleak" is used. Computational analysis shows that the relationship between the heat leak and vapor/liquid ratio is linearly inversed. Heat leak increases with increasing of car acceleration when fuel vapor/liquid ratio is less than 0.5 and decreases when fuel vapor/liquid ratio is greater than 0.5. The difference between maximum and minimum heat leak for full tank is about 12 percents. For the fuel vapor/liquid ratio equal to 0.5 heat leak does not depend on car acceleration.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.213-218
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• 1997

CNG dual fuel engine for heavy duty diesel engine has been equipped to a Korean bus engine and tested to compare th engine performance and the emission characteristics with the existing diesel fueled engine. The results are summarized as follows. Diesel fueled engine has the fuel injection timing of BTDC17°. The injection timing of CNG modified engine is retarded to BTDC14° for reduction of NOx. Performance optimization has been carried out to have engine power equivalent to or better than the diesel fueled engine. Smoke is decreased by 85% by Korean smoke 3 mode test. By 6 mode test CO is increased by 313% and THC is increased by 1407%. NOx is decreased by 27%. Even though THC is increased very much, it's not too serious problem since CO and THC emission of diesel engine are very little compared to gasoline engine and THC don't give bad effect on human health. But the reduction technologies of CO and THC need to be considered.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.178-185
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• 1998

To reduce the particulate matter and nitrogen oxides from diesel engine, many studies are proceeding and being accomplished practically. In this situation CNG engine has important meaning both as a clean fuel and an alternative energy. In order to present the direction and application of CNG, we simulated various operating conditions, that is, spark timing, compression ratio and fuel composition etc. Thus we try to understand how those affect performance and exhaust characteristics. The simulation program results found that the optimum combustion start angle was 21$^{\circ}$ at 1800rpm and fuel composition affects performance and emissions, also we could understand the formation of emission as crank angle is changed.

• 한국자동차공학회논문집
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• 제8권2호
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• pp.57-63
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• 2000

This paper deals with a study on combustion and emission characteristics of a direct injection diesel engine dual fueled with natural gas. Dual fuelling systems tend to emit high unburned fuel especially at low load, resulting in a decreased thermal efficiency. This is because natural gas-air mixtures are too lean for flame to propagate under low load conditions. Suction air quantity and injection timing controls are very useful to improve emissions and thermal efficiency at low load.

• 융복합기술연구소 논문집
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• 제3권2호
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• pp.57-60
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• 2013

The purpose of this study is to analysis of how to calculate fuel efficiency in major development countries (U.S. and Europe) and energy consumption formular derivation of domestic CNG fuel and prove by vehicle test. The formula of fuel consumption is different in mpg(mile per gallon), l/100km, and km/l each countries. CNG fuel has a significant impact on fuel density, composition, and Hydro-Carbon ratio. So, this study how to measurement and calculation procedures of CNG gaseous fueled vehicle energy consumption rate.

• 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.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.86-92
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• 2003

To analyze the characteristics of ozone formation, measurements of the concentrations of individual exhaust hydrocarbon species have been made under various engine operating parameters in a 2-liter 4-cylinder engine for natural gas and LPG. Tests were performed at constant engine speed, 1800 rpm for two compression ratios of 8.6 and 10.6, with various operating parameters, such as excess air ratio of 1.0~1.6, bmep of 250~800 na and spark timing of BTDC 10~$55^{\circ}$. It was found that the natural gas gave the less ozone formation than LPG in various operating conditions. This was accomplished by reducing the emissions of propylene($C_3H_6$), which has relatively high maximum incremental reactivity factor, and propane($C_3H_8$) that originally has large portion of LPG. In addition, the natural gas show lower values in the specific reactivity and brake specific reactivity. Higher compression ratio of the test engine showed higher non methane HC emissions. However, specific reactivity value decreased since fuel species of HC emissions increase. brake specific reactivity showed almost same values under high bmep, over 500kPa for both fuels. This means that the increase of non methane HC emissions and the decrease of specific reactivity with higher bmep affect each other simultaneously. With advanced spark timing, brake specific reactivity values of LPG were increased while those of natural gas showed almost constant values.

• 한국자동차공학회논문집
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• 제19권3호
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• pp.38-43
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• 2011

A CNG/diesel dual-fuel engine uses CNG as the main fuel and injects a small amount of diesel as an ignition priming. This study proposed the modification of the existing diesel engine into a dual-fuel engine that injects diesel with a high pressure by common rail direct injection (CRDI) and by injecting CNG at the intake port for premixing. And experiment was progressed for understanding about effect of CNG mixing ratio. The CNG/diesel dual-fuel engine showed equally satisfactory coordinate torque and power regardless of CNG mixing ratio. The PM emission was low at any CNG mixing ratio because of very small diesel pilot injection. In case of NOx and HC, high CNG mixing ratio showed low NOx and HC emissions at low speed. At medium & high speed, low CNG mixing ratio showed low NOx and HC emissions. Therefore, it would be optimized by controlling CNG mixing ratio.

• 디자인학연구
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• 제19권4호
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• pp.175-186
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• 2006

21세기는 화석연료 자원의 고갈과 더불어 자동차의 배기가스로 인한 환경오염 문제의 심각성이 더욱 심화되어 화석연료를 대신할 수 있는 대체에너지 개발에 선진국을 비롯한 각 국에서 연구가 진행되고 있다. 제천은 주변에 많은 문화재 단지와 역사문화 유적지를 갖고 있다. 뿐만 아니라 다양한 문화 행사도 주최하고 있어 관광자원도 고루 갖추었다고 할 수 있다. 그러나 제천을 비롯하여 주변의 관광지들을 연계할 수 있는 교통수단이 미비하고 일반적이어서 특별한 교통수단을 개발할 경우 또 다른 관광자원으로서의 역할이 기대된다. 제천지역의 특성화를 위한 친환경운송수단 교통시스템의 설정을 위해 이론적 배경으로 제천지역의 특성을 조사하였다. 방향설정을 위해 기존의 성공적인 사례연구를 통해 교통시스템을 연구하였다. 또한 친환경 에너지원을 사용하는 운송수단인 태양열자동차, 연료전지자동차, 하이브리드 카, 전기자동차, 천연가스 자동차 등의 내용, 방식, 구조 및 장 단점 등을 연구 조사하였다. 연구조사를 바탕으로 제천지역에 적합한 친환경운송수단의 가능한 방향을 세 가지로 제안하였다. 제안된 안을 각 계 전문가들의 자문을 통해 비교 검토한 후 가장 적합한 교통시스템, 자동차 에너지원 및 차량형식, 승차인원과 차량제원 등을 결정하였다. 결정된 방향으로 자동차디자인 프로세스에 따라 디자인 안을 도출하고자 하였다. 제천과 주변지역을 연계하고 청정지역의 이미지를 살릴 수 있도록 친환경 에너지원을 사용하는 교통수단의 특별한 익스테리어디자인을 제천시청과 충북도청에 제안하므로 제천을 관광특성화 할 셔틀버스의 디자인비즈니스를 개발하고자 하였다.