• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.1-11
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• 2000

This study is aimed to develop a proto-type LPG engine for medium-duty commercial vehicles in order to substitute for conventional diesel engine. Recently, it is recognized that diesel engines are main cause for smoke pollution in urban site. So, it is expected to reduce this environmental emission by developing and substituting LPG engine which has the advantage of practical use in a short development period in aspects of infrastructures. For that, after analysing the specifications and performance characteristics of a base diesel engine, parts of combustion chamber, intake system, fuel supply and ignition systems suitable for LPG combustion were re-designed and manufactured. And and engine controller for fuel supply and ignition distributions was matched by feedback mapping based on the speed-load conditions. The torque and power of LPG engine were increased by 6∼12% on the overall driving conditions compared to the base diesel engine, and fuel consumption rate marked the similar level based on the fuel price. Exhaust emissions such as THC, CO, NOx recorded the same order with conventional LPG engine for passenger car.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.234-243
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• 2018

Since September 2017, a small diesel vehicle certification test mode has been enhanced from NEDC to WLTC. The main reason for the change of the certification test mode is that the certification test mode of the emission control standard of the diesel vehicle does not sufficiently reflect various driving patterns of the actual roads. Several automakers have developed after-treatment systems such as LNT, SCR, and DPF to meet enhanced emissions regulations. In this study, four small diesel cars were selected for sale in Korea, and the exhaust gas measurement test was performed in the WLTC mode, which reflects the driving characteristics of the actual roads. As a result of test, LNT vehicle exceeded Euro 6 NOx regulation and SCR vehicle satisfied Euro 6 NOx regulation. In addition, both LNT and SCR systems showed high NOX emission characteristics due to speed, RPA and Vxa. For the PN, all test vehicles were fitted with a DPF and met the Euro 6 PN regulations, with similar PN emissions results in LNT and SCR system.

• Environmental Analysis Health and Toxicology
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• v.25 no.2
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• pp.111-120
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• 2010

DEPs (diesel exhaust particles) like any other particles can be also inhaled into lung to participate in a damaging reaction to the organ. Possible damages might be apoptosis and inflammatory responses to the cells in respiratory track. The aim of this study was cytotoxicity evaluation of DEPs from five in-use diesel vehicles using a murine macrophage cell (RAW 254.7). We found that most DEPs have a considerable cytotoxicity compared to the control and SRM 2975. When measured by MTT assay and extents of apoptosis, DEPs of two highmileage vehicles had higher toxicity than those of the other three low-mileage vehicles tested. Although mRNA expression level of TNF-${\alpha$ somewhat explains the trend of cytotoxicity and apoptosis, that of IL-1$\beta$ did not. Correlation studies among the extents of MTT assay, apoptosis, and TNF-$\alpha$ expression showed that the extents between apoptosis and TNF-$\alpha$ expression was most highly correlated (r=0.96). These results suggest that cytotoxicity of various DEPs could be compared easily by measuring the extent of apoptosis or TNF-$\alpha$ expression by DEPs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.7
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• pp.737-744
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• 2012

A mobile emission laboratory (MEL) was designed to measure the amount of traffic pollutants, with high temporal and spatial resolution under real conditions. Equipment for the gas-phase measurements of CO, NOx, $CO_2$, and THC and for the measurement of the number, concentration, and size distribution of fine and ultra-fine particles by an FMPS and CPC was placed in a minivan. The exhausts of different types of vehicles can be sampled by an MEL. This paper describes the technical details of the MEL and presents data from the experiment in which a car chases passenger vehicles fuelled by diesel and gasoline. The particle number concentration in the exhaust of the diesel vehicle was higher than that of the gasoline vehicle. However, the diesel vehicle with a DPF emitted fewer particles than the vehicle equipped with a gasoline direct injection engine, with particle diameters over 50 nm.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.225-236
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• 2004

Diesel engines which emit a lot of PM and NOx have been known as a main air polluter. Especially, diesel particulate matters (OPM) including black smoke are hazardous air pollutants to human health and environment. The nations retaining advanced engine technologies have reinforced emission regulations. To meet these regulations diesel engine manufacturers have developed low-emission diesel engines, aftertreatment equipments, alternative fuel technologies and so on. In this study, particle number concentrations characteristics according to particle size and engine driving conditions were analyzed when these low-emission technologies were applied. There was a tendency of increasing particle number concentrations from heavy-duty diesel engines with increasing engine rpm and load rate. In the cases of COPF (Catalytic Diesel Particulate Filter), CNG (Compressed Natural Gas) engine and ULSD (Ultra Low Sulfur Diesel) more than 99% of particle number concentration were removed.

• Tribology and Lubricants
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• v.26 no.2
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• pp.111-121
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• 2010

The purpose of this study is to examine the effect of diesel soot contents on the deterioration of engine oil in terms of the changes in the dielectric constants of diesel engine oils. Therefore, it is figured out the level of oil deterioration by investigating how are the dielectric constants of diesel engine oils changed according to changes in diesel soot contents. The measured data will be able to be used as the reference data to judge the level of oil deterioration induced by diesel soot when the previously developed oil deterioration sensor will be applied at diesel vehicles in the future.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.745-756
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• 2013

The purpose of this study is to evaluate representativeness of fuel-based emission factors. Twelve light-duty diesel vehicles which meet Euro-3 to 5 legislative emission limits were selected for emission tests. Second-by-second modal emission rates of vehicles were measured on a standard laboratory chassis dynamometer system. An off-cycle driving cycle was developed as a representative Korean real-world on-road driving cycle. Fuel-based emission factors were developed for short trip segments that involved in the selected driving cycle. Each segment was defined to have unit travel distance, which is 1 km, and characterized by its average speed and Relative Positive Acceleration (RPA). Fuel-based $NO_x$ emission factors demonstrate relatively good representativeness in terms of vehicle operation conditions. $NO_x$ emission factors are estimated to be within ${\pm}20%$ of area-wide emission factor under more than 40% of total driving situations. This result implies that the fuel-based $NO_x$ emission factor could be practically implemented into the on-road emission management strategies, such as a remote sensing device (RSD). High emitting vehicles as well as high emitting operating conditions heavily affect on the mean values and distributions of CO and THC emission factors. Few high emitting conditions are pulling up the mean value and biasing the distributions, which weaken representativeness of fuel-based CO and THC emission factors.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.754-762
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• 1998

Exhaust emissions in diesel engine are affected by fuel properties but the reason for this is not clear. Especially the recent strong interest in using low-grade fuel demands extensibe investigation in order to clarify the exhaust emissions. Bio-Diesel oil has a great possibility to solve the pollution problem caused by the exhaust gas from diesel engine vehicles. The use of bio-oils in diesel engines has received considerable atten-tion to the forseeable depletion of world oil supplies. So bio-diesel oil has been attracted with attentions for alternative and clean energy source. The purpose of this paper is to evaluate the fea-sibility of the rice-bran oil for alternative fuel in a diesel engine with rgard to exhaust emis-sions.

• Journal of ILASS-Korea
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• v.17 no.4
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• pp.205-209
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• 2012

This study focused on comparing macroscopic characteristics of DME and diesel fuel experimentally. DME fuel is one of the most promising alternative fuels because of its superiority in atomization characteristic and clearness in terms of exhaust gas compared with existing fossil fuels. In addition, DME fuel has high cetane number so it could be applied to compression ignition engine. However because DME fuel exists in gas phase at room temperature and atmospheric pressure, and it corrodes rubber parts of fuel line, DME fuel is hard to apply to commercial vehicles. To establish knowledge about DME fuel and furthermore, to develop commercial DME vehicles such as passenger cars, many research have been proceeded steadily. The present study, by comparing spray characteristics of DME fuel to those of diesel fuel, improved atomization characteristics in DME were revealed. Injection quantity measurement and spray visualization experiment were progressed and it was revealed that DME fuel shows small injection quantity than that of diesel fuel and axial development of spray in terms of spray tip penetration decreases when DME fuel was injected.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.680-685
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• 2006

The latest trend in the automotive industry demands the development of high stiffness car bodies and the securement of inter-system performance for low vibration and noise vehicles. This demand, however, conflicts with need for light weight design and greater fuel efficiency, thus raising the importance of optimization design to satisfy both developmental goals. We chose two European medium sedans, which has gasoline engine and diesel one, to elucidate the noise characteristics of diesel passenger cars, whose sales have been increasing in both Korea and Europe. In the present study a systematic experiment was conducted to analyze the noise characteristics in diesel cars. we made it possible for differentiating car management according to customer demand while allowing for improved commercial feasibility. it was possible to improve interior noise by 2 dB(A) on average sound pressure level. As a result, by 4% higher on articulation index(AI).