• Asian Journal of Atmospheric Environment
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• 제9권1호
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• pp.78-85
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• 2015

In the past several decades, biofuels have emerged as candidates to help mitigate the issues of global warming, fossil fuel depletion and, in some cases, atmospheric pollution. To date, the only biofuels that have achieved any significant penetration in the global transportation sector are ethanol and biodiesel. The global consumption of biodiesel was rapidly increased from 2005. The goal of this study was to examine the chemical composition on particulate pollutant emissions from a diesel engine operating on several different biodiesels. Tests were performed on non-road diesel engine. Experiments were performed on 5 different fuel blends at 2 different engine loading conditions (50% and 75%). 5 different fuel blends were ultra-low sulfur diesel (ULSD, 100%), soy biodiesel (Blend 20% and Blend 100%) and canola biodiesel (Blend 20% and Blend 100%). The chemical properties of particulate pollutants were characterized using an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Organic matter and nitrate were generally the most abundant aerosol components and exhibited maximum concentration of $1207{\mu}g/m^3$ and $30{\mu}g/m^3$, respectively. On average, the oxidized fragment families ($C_xH_yO_1{^+}$, and $C_xH_yO_z{^+}$) account for ~13% of the three family sum, while ~87% comes from the $C_xH_y{^+}$ family. The two peaks of $C_2H_3O_2$ (m/z 59.01) and $C_3H_7O$ (m/z 59.04) located at approximately m/z 59 could be used to identify atmospheric particulate matter directly to biodiesel exhaust, as distinguished from that created by petroleum diesel in the AMS data.

• 한국대기환경학회지
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• 제32권6호
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• pp.613-623
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• 2016

In this study, pilot experiments were conducted by setting operation conditions to analyze characteristics of emission for air pollutant from small two-stroke engines. Emission factors of the measured concentration of pollutant were compared with EEA. Emission factor of CO analyzed by experiments - concentration, flow rate, fuel consumption, etc.- was estimated at 816,011 g-CO/ton-fuel in average. It was confirmed that more than 80% of the fuel consumption is discharged to the Carbon Monoxide, and that as the engine load becomes higher, emission factor of CO increases in the form of log function. The average emission factor of $NO_x$ and $PM_{10}$ was $3,801g-NO_x/ton-fuel$ and $3,730g-PM_{10}/ton-fue$l each. The deviation was not large by comparing the fuel-based emission factor of EEA and the result of this study. Since considerable pollutants are expected to be discharged from the small two-stroke engines, continuous research and support of the policy is required.

• 한국분무공학회지
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• 제29권2호
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• pp.53-59
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• 2024

Cars are one of the main causes of air pollution in large cities, and 34.6% of domestic air pollution emissions come from mobile sources, of which cars account for 69.6%. In particular, the importance of nitrogen oxides (NOx) and particulate matter (PM), which are major pollutants in diesel vehicles, is increasing due to their high contribution to emissions. Therefore, in this study, the problem of natural regeneration caused by low exhaust gas temperature during low speed and low load operation was solved by applying a complex regeneration DPF that is not affected by temperature conditions to large diesel vehicles with higher driving time and engine displacement than small and medium-sized vehicles. And the feasibility of application to large diesel vehicles was reviewed by measuring the emission reduction efficiency. As a result of the reduction efficiency test on the actual vehicle durability product, PM showed a reduction efficiency of 84% to 86%, and the reduction efficiency of gaseous substances showed a high reduction efficiency of over 90%. The actual vehicle applicability test was completed with three driving patterns: village bus vehicle, police car, and road-going construction equipment vehicle, and no device problems occurred until the end of the test. Both load and no-load smoke measurement results showed a smoke reduction efficiency of over 96%.

• 한국터널지하공간학회 논문집
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• 제22권3호
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• pp.323-335
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• 2020

본연구에서는 현행 도로터널의 환기설계기준의 적정성을 검토하기 위하여 사례조사를 수행하고, 5개 터널을 대상으로 입자상 및 가스상 물질의 농도를 현장측정 하였다. 사례조사 결과는 설계기준 대비 TSP (가시도)는 27.9%, CO는 1.6%, NOx는 3.4% 수준으로 분석되었고, 현장측정 결과는 각각 2.6%, 0.8%, 0.2%의 수준에 불과하였다. 또한 5개 터널에 대한 입자상물질(TSP)의 입경분석 결과, 타이어 마모, 재부유 분진 등의 입자라 할 수 있는 PM10 이상의 입경의 영역은 20.4%로 나타났다. 따라서 현행 도로터널 환기설계 기준으로 제시된 입자상물질은 엔진배출량 외에 비엔진배출량에 대한 고려가 반드시 필요하며, 최근의 연구결과를 통한 제작차 오염물질 배출량 및 경사속도 보정계수 등을 적용하여 대상오염물질에 대한 설계기준의 합리적인 개정이 요구되며 WRA (PIARC)에서도 환기설계 기준의 개정 필요성을 권고하고 있다. 현행 터널 내 낮은 환기설비(제트팬) 가동율을 고려할 경우 향후 터널 내 운영상 관리기준의 신설에 대한 필요성이 제기된다.

• International Journal of Automotive Technology
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• 제6권3호
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• pp.221-227
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• 2005

Aim of this study is to investigate an aerodynamic effect of a drag-reducing device on a heavy-duty truck. The vehicle experiences two different kinds of aerodynamic forces such as drag and uplifting force (or downward force) as it is traveling straight forward at constant speed. The drag force on a vehicle may cause an increase of the rate of fuel consumption and driving instability. The rolling resistance of the vehicle may be increased as result of the negative uplifting or downward force on the vehicle. A device named roof-fairing system has been applied to examine the reduction of aerodynamic drag force on a heavy-duty truck. As for a engineering design information, the drag-reducing system should be studied theoretically and experimentally for the best efficiency of the device. Four different types of roof-fairing model were considered in this study to investigate the aerodynamic effect on a model truck. The drag and downward force generated by vehicle has been obtained from numerical calculation conducted in this study. The forces produced on four fairing models considered in this study has been compared each other to evaluate the best fairing model in terms of aerodynamic performance. The result shows that the roof-fairing mounted truck has bigger negative uplifting or downward force than that of non-mounted truck in all speed ranges, and drag force on roof-fairing mounted truck has smaller than that of non-mounted truck. The drag coefficient $(C_D)$ of the roof-fairing mounted truck (Model-3) is reduced up to $41.3\%$ than that of non-mounted trucks (Model-1). A downward force generated by a roof-fairing mounted on a truck is linearly proportional to the rolling resistance force. Therefore, the negative lifting force on a heavy-duty truck is another important factor in aerodynamic design parameter and should be considered in the design of a drag-reducing device of a tractor-trailer. According to the numerical result obtained from present study, the drag force produced by the model-3 has the smallest of all in all speed ranges and has reasonable downward force. The smaller drag force on model-3 with 2/3h in height may results of smallest thickness of boundary layer generated on the topside of the container and the lowest intensity of turbulent kinetic energy occurs at the rear side of the container.

• 한국응용과학기술학회지
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• 제35권4호
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• pp.1108-1119
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• 2018

대기오염에 대한 관심은 국내 외에서 점진적으로 상승하고 있으며, 자동차 및 연료 연구자들은 청정(친환경 대체연료) 연료와 연료품질 향상 등을 위해 새로운 엔진 설계, 혁신적인 후 처리 시스템 등의 많은 접근을 통하여 차량 배출가스와 온실가스를 감소시키려고 노력하고 있다. 이러한 연구들은 주로 차량의 배출가스 (규제 및 미규제물질, PM 입자 배출 등)와 온실가스의 두 가지 이슈로 진행되고 있다. 자동차의 배출가스는 환경오염과 인체에 악영향을 주는 많은 문제를 일으키고 있다. 이러한 배출가스를 줄이기 위하여 각국에서는 배출가스 시험모드를 새로 만들어 규제하고 있다. 2007 년부터 UN ECE의 WP.29 포럼에서 배출가스 인증을 위한 전 세계의 조화된 light-duty 차량 시험 절차 (WLTP)가 개발되었다. 이 시험 절차는 유럽과 동시에 국내 light-duty 디젤 차량에도 적용되어졌다. Light-duty 차량의 대기오염 물질 배출량은 거리 당 무게로 규제되어 있어 주행주기가 결과에 영향을 미칠 수 있다. 차량의 배출가스는 주행 및 환경조건, 주행습관 등에 따라 크게 달라진다. 극단적인 외기온도는 배출가스를 증가시키는데, 이것은 더 많은 연료가 실내를 가열하거나 냉각해야하기 때문이다. 또한 높은 주행속도는 증가된 항력을 극복하기 위해 필요한 에너지로 인해 배출가스 량을 증가시킨다. 일반적으로 상승하는 차량속도와 비교할 때, 급격한 차량가속도도 배출가스를 증가시킨다. 부가적인 장치 (에어컨 또는 히터)와 도로경사 또한 배출가스를 증가시킨다. 본 연구에서는 3대의 light-duty 차량을 가지고 light-duty 차량의 배출가스 규제에 사용되는 WLTP, NEDC 및 FTP-75로 시험을 하였으며, 배출가스가 다른 주행 사이클에 의해 얼마나 많은 영향을 받을 수 있는지를 측정하였다. 배출 가스는 통계적으로 의미있는 차이를 보이지 않았다. 최대 배출 가스는 주로 냉각 된 엔진 조건에 의해 야기되는 WLTP의 저속 단계에서 발견된다. 냉각 된 엔진 상태에서 배출가스의 양은 시험 차량과 크게 다르다. 이는 WLTP 구동 사이클에 대처하기 위해 다른 기술적 솔루션이 필요하다는 것을 의미한다.