• Journal of Advanced Marine Engineering and Technology
• /
• 제34권4호
• /
• pp.508-514
• /
• 2010

본 논문은 커먼레일 디젤엔진의 정속운전시 배출되는 나노크기의 입자상 물질을 분석하는데 초점을 두었다. 디젤산화촉매 후단에서 나노입자상 물질의 개수농도 저감수준은 크지 않았으나 매연여과장치 후단에서 분석한 결과 1,000배 정도 저감되는 결과를 확인하였다. 고속 고부하 조건에서는 매연여과장치의 자연재생 효과로 인해 입자상 물질은 증가하였다. 연료분사시기를 BTDC $6^{\circ}CA$ 에서 ATDC $4^{\circ}CA$까지 지각시킨 결과 입자상 물질의 개수농도는 감소하였지만 최지각 조건인 ATDC $9^{\circ}CA$에서는 증가하는 결과를 확인하였다. EGR 적용시 핵화모드 입자상 물질은 저감되는 경향을 보였으며 축적모든 입자는 증가하였다.

• 한국연소학회지
• /
• 제15권3호
• /
• pp.57-66
• /
• 2010

The purpose of this paper is to investigate the effects of fuel injection strategy and engine load on the structure and emissions characteristics of a DI diesel engine with 1.6L of piston displacement. In order to analyze the particulate matter (PM) and exhaust emissions characteristics in a direct injection diesel engine, the quantity of PM and exhaust emissions (including HC, CO and $NO_X$) were investigated under various injection strategies and engine loads. Two different injection strategies (one pilot/main injection and two pilots/main injection) was investigated under the various engine loads. A thermophoretic sampling method with a scanning electron microscope (SEM) were used to obtain the PM morphology (including primary particles, the size of the agglomerates, the number of agglomerates, the fractal dimension). The quantity of soot gradually increased with increasing engine load at both injection strategies. The primary particles in the PM agglomerates indicate that the average of the primary particle and radius of gyration increased as the engine load increased.

• 한국환경보건학회지
• /
• 제38권4호
• /
• pp.277-290
• /
• 2012

Objectives: Diesel engine exhaust (DE) accounts for a significant percentage of air pollutants that are associated with various health outcomes including mortality, asthma, chronic bronchitis, respiratory tract infection, etc. In June, 2012, the International Agency for Research on Cancer (IARC) released the assessment results that classified DE as "carcinogenic to humans" (Group 1). This review is therefore focused on the lung cancer risks of DE. Methods: Literatures were searched using PubMed with key words of "diesel exhaust", "lung cancer", and other related terms for the period between 1990 and 2012. A total of 295 articles were searched and sixteen epidemiologic studies were identified as potentially relevant. Results: Sixteen epidemiologic studies about the lung cancer risks of workers exposed to DE in various occupations were summarized in two tables, 1) retrospective cohort studies and 2) case-control studies. Increased lung cancer risk, although not always smoking adjusted, was observed in 6 out of 8 retrospective cohort studies and 4 of 8 case-control studies. Conclusions: Diesel fuel is widely used in Korea. Exposure to DE is confirmed to be a human carcinogen by IARC. Noncancer health risks of DE also need careful attention as DE is a major source of fine-particle pollution. Along with the efforts for reducing the DE emission through improvements of diesel engines and fuel, and the use of alternative fuels, comprehensive health risk assessment of DE should be conducted to minimize the adverse health effects.

• 한국대기환경학회지
• /
• 제19권2호
• /
• pp.133-143
• /
• 2003

Numerous evidence have been reported that fine particulate matters can play an important role in threatening human health. Recently concerns on fine particle pollution from various engines may require re-examination of particulate emission standards. The particles emitted by most diesel engines are mainly divided into their size ranges such as Dp< 50 nm and 50 nm< Dp< 1,000 nm. In this work, the number concentration and the size distribution of fine particles emitted from an exhaust manifold of a railroad diesel engine were measured under load test conditions using a scanning mobility particle sizer (SMPS). The fine particles observed were within the range of 7 to 304 nm under different load conditions with two different dilution ratios. The fine particles exhibited unique patterns showing bimodal shapes in size distribution.

• International Journal of Automotive Technology
• /
• 제8권2호
• /
• pp.165-177
• /
• 2007

Predictions of diesel particulate filtration are typically made by modeling of a particle collection, and providing particle trapping levels in terms of a pressure drop. In the present study, a series of single channel diesel particulate filter (DPF) experiments are conducted, the pressure traces are inversely analyzed and essential filtration parameters are deducted for model closure. A DPF filtration model is formulated with a non-linear description of soot cake regression. Dependence of soot cake porosity, packing density, permeability, and soot density in filter walls on convective-diffusive particle transportation is examined. Sensitivity analysis was conducted on model parameters, relevant to the mode of transition. Soot cake porosity and soot packing density show low degrees of dispersion with respect to the Peclet number and have asymptotes at 0.97 and $70\;kg/m^3$, respectively, at high Peclet number. Soot density in the filter wall, which is inversely proportional to filter wall Peclet number, controls the filtration mode transition but exerts no influence on termination pressure drop. The percolation constant greatly alters the extent of pressure drop, but is insensitive to volumetric flow rate or temperature of exhaust gas at fixed operation mode.

• 한국자동차공학회논문집
• /
• 제22권7호
• /
• pp.8-15
• /
• 2014

In order to satisfy stringent future emission regulation in diesel engines, systematic approaches to mitigate the harmful exhaust emissions were developed, such as engine hardware, fuel injection equipment, engine control, and after-treatment system. In this study, to improve the nano-particle and NOx emissions from a state-of-the-arts diesel engine, effect of various EGR and fuel injection pressure with combustion analysis were evaluated. Size-resolved nano-particle and NOx emissions showed trade-off characteristics with various EGR rate and increment of fuel injection pressure.

• 한국분무공학회지
• /
• 제22권4호
• /
• pp.190-196
• /
• 2017

The aim of this work is to investigate the combustion and exhaust emission characteristics of low-temperature combustion (LTC) at various EGR test conditions using a single cylinder common-rail diesel engine. In high EGR rate combustion mode with DME fuel, 30% (${\Phi}=0.61$) and 50% (${\Phi}=0.86$) of EGR were respectively examined, and then the combustion, exhaust emissions, nano-particle characteristics of each cases were measured. From these results, it revealed that The ignition delay and combustion duration are prolonged as the increase of EGR rate. In addition, at an advanced injection timing (BTDC $30^{\circ}$), ignition delays were fairly increased because the dilution effect of EGR and also low charge in-cylinder temperature created a lean mixture, thus decreased the peak release rate.

• 한국입자에어로졸학회지
• /
• 제4권2호
• /
• pp.51-67
• /
• 2008

In this study, we devoted to kinetic measurement of the catalytic oxidation of iron-containing flame soot particles and better understanding the role of catalytic particles on carbon oxidation in particular at low temperature, targeting on autothermal regeneration of diesel particulate filter by diesel exhaust gas. Carbon-based Fe-containing particles generated by spraying ferrocene-doped diesel fuel in an oxy-hydrogen flame are tested and compared with a commercial carbon black powder for thermogravimetric analysis (TGA), secondary ion mass spectrometry (SIMS), Fourier-transform infrared spectroscopy (FTIR), Induced coupled plasma-Atomic emission spectroscopy (ICP-AES), and High-resolution transmission electron microscopy (HR-TEM). As a result, we found that a small amount of the ferrocene addition led to significant reductions in a on-set temperature and an activation energy of the carbon oxidation as well. An oxygenated surface complex forming at the particle surface could be thought as active species that would be readily consumed in particular at low temperature.

• International Journal of Automotive Technology
• /
• 제2권4호
• /
• pp.123-133
• /
• 2001

An important goal in diesel engine research is the development of a means to reduce the emission of oxides of nitrogen ($NO_x$) and soot particulate. A phenomenological model based on the multizone concept is used in the current paper to analyze and compare the effects of exhaust gas recirculation (EGR) and split fuel injection on emission from a compression-ignited, direct-injection engine. The present results show that $NO_x$ can be reduced with a minimum penalty of soot particle emission with cooled EGR. Compared with EGR, split fuel injection has a higher soot penalty at a given level of $NO_x$ reduction.

• 한국자동차공학회논문집
• /
• 제20권3호
• /
• pp.88-97
• /
• 2012

To measure the traffic pollutants with high temporal and spatial resolution under real conditions, a mobile emission laboratory (MEL) was designed. The equipment of the mini-van provides gas phase measurements of CO, NOx, CO2 and THC (Total hydrocarbon), and number density & size distribution measurements of fine and ultra-fine particles by a fast mobility particle sizer (FMPS) and a condensation particle counter (CPC). The inlet sampling port above the bumper enables the chasing of different type of vehicles. This paper introduces the technical details of the MEL and presents data from the experiment in which a MEL chases a city bus fuelled by diesel, DME and Bio-diesel. The dilution ratio was calculated by the ratio of ambient NOx and tail-pipe NOx. Most particles from the bus fuelled by diesel were counted under 300 nm and the peak concentration of the particles was located between 30 and 60 nm. However, most particles in the exhaust of the bus fuelled by DME were nano-particles (diameter: less than 50 nm). The bus fuelled by Bio-diesel shows less particle emissions compare to diesel bus due to the presence of the oxygen in the fuel.