• Journal of ILASS-Korea
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• v.26 no.3
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• pp.111-119
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• 2021

Deteriorated agricultural diesel engines using mechanical fuel injection systems have low fuel injection pressures. And they are not equipped with an exhaust gas abatement device, so it produces a lot of exhaust gas. Remanufactured used injectors can reduce emissions because spray characteristics are improved. In addition, remanufacturing is environmentally friendly and economical compared to producing new parts. For efficient injector remanufacturing, it is necessary to conduct a comparison experiment on the spray characteristics of an used mechanical injector and a new injector of the same model. In this study, the spray characteristics of the two injectors were compared by performing an injection quantity measurement and a spray visualization experiment. As a result, the used injector had a larger injection quantity, a shorter spray tip penetration, a wider spray angle and a smaller spray area than the new injector.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.3
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• pp.175-185
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• 2023

Many small vessels such as fishing boats operate in the world's oceans; accordingly, interest in these small vessels' exhaust-gas problem is increasing. Research on the application of electric-propulsion technology has been steadily conducted; however, the subject is limited to research ships or leisure boats, while research on application efficiency remains insufficient. This study attempts to apply lithium-battery electric-propulsion technology to small ships. A gross tonnage of 9.77, a representative fishing boat, is to be redesigned as a fully electrified ship. Without changing the main cabin's dimensions and fuel tanks, the ship's propulsion system is redesigned based on a lithium-battery electric-propulsion system. In addition, the redesigned system is compared with the original sample ship's diesel-propulsion system for application-effect analysis. The results indicate that under controlled sailing conditions, the weight and volume of the electric-propulsion system are 9.5 and 10.5 times those of the diesel-propulsion system, respectively. These values indicate that the system cannot meet fishing boats' high endurance requirements. Therefore, under the existing technical conditions, applying the full lithium-battery electric-propulsion system to solve the problem of high emissions from fishing boats shows limited feasibility.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1045-1050
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• 2014

$N_2O$(Nitrous Oxide) is known as the third major GHG(Green House Gas) following $CO_2$(Carbon Oxide) and $CH_4$(Methane). The GWP(Global Warming Potential) factor of $N_2O$ is 310 times as large as that of $CO_2$ because $N_2O$ in the atmosphere is very stable, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. Investigation on the cause of the $N_2O$ formation have been continuously reported by several researchers on power sources with continuous combustion form, such as a boiler. However, in the diesel engine, research on $N_2O$ generation which has effected from fuel components has not been conducted. Therefore, in this research, author has investigated about $N_2O$ emission rates which was changed by nitrogen and sulfur concentration in fuel on the diesel engine. The test engine was a 4-stroke direct injection diesel engine with maximum output of 12 kW at 2600rpm, and operating condition of that was set up at a 75% load. Nitrogen and sulfur concentrations in fuel were raised by using six additives : nitrogen additives were Pyridine, Indole, Quinoline, Pyrrol and Propionitrile and sulfur additive was Di-tert-butyl-disulfide. In conclusion, diesel fuels containing nitrogen elements less than 0.5% did not affect $N_2O$ emissions in the all concentrations and kinds of the additive agent in the fuel. However, increasing of the sulfur additive in fuel increased $N_2O$ emission in exhaust gas.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.13-22
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• 2017

Objectives: The objective of this study was to evaluate the exposure levels of door-to-door deliverers to fine particulate matter (PM2.5). Another objective was to confirm the general working patterns of door-to-door deliverers via survey. Methods: In the city of Daegu, ten door-to-door deliverers who wished to join the study were recruited. The general working characteristics of door-to-door deliverers were surveyed using self-reported questionnaires. In the cabin of each car driven by a deliverer, a real-time PM2.5 sampler (Sidepak, Model AM510, TSI Inc., MN, USA) and a GPS device (GPS 741, Ascen, Korea) were installed. Each deliverer was monitored for four days per week so that each day could be monitored at least four times. Results: A total of 40 measurements of PM2.5 concentrations were taken during delivery of parcels. The average exposure levels of door-to-door deliverers to PM2.5 was $44.62{\mu}g/m^3$ ($7-9443{\mu}g/m^3$. Exposure levels to PM2.5 according to the day of the week and coverage areas were not significantly different (p>0.05). Door-to-door deliverers using trucks with older diesel engines manufactured before 2006 had significantly higher exposure levels to PM2.5 than in the case of trucks with diesel engines manufactured after 2006 (p<0.05). Many of the door-to-door deliverers reported the status of having windows open during the delivery task. During delivery services, the working hours spent in residential areas were higher than on roadsides, but exposure levels to PM2.5 in residential areas and on roadsides were $46.17{\mu}g/m^3$ and $49.90{\mu}g/m^3$, respectively. Real-time PM2.5 exposure levels were significantly different between roadways and residential areas (p<0.001). Conclusions: PM2.5 exposure levels of door-to-door deliverers were found to be affected by higher vehicle emissions from the roadsides near their vehicle during deliveries and while driving to other locations compared to by PM2.5 from the diesel engines of their own trucks. Particle concentrations from roadsides and emissions from nearby vehicles through open windows were the main source of PM2.5.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.117-124
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• 2011

Automotive engines require strategies to fulfill the emission regulations in terms of NOx and PM. A dramatic reduction in NOx and PM emissions could be achieved with high pressure injection, innovative combustion strategies and EGR. Recently, Lean NOx Trap (LNT) and Urea-SCR are considered as more practical strategy to suppress the engine-out emissions substantially for copying with severe regulation. These systems need to reduce the reducing agent injection system which has a huge impact on NOx purification efficiency. In this paper, different three injectors have been used to investigate spray characteristics and engine emission test was conducted to clarify the effect of these injectors on the NOx reduction.

• Journal of ILASS-Korea
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• v.21 no.4
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• pp.214-222
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• 2016

Changes in road infrastructure affect driving patterns and pollutant emission characteristics. we analyzed the changes in driving patterns and pollutant emission characteristics of the driving route via measured driving patterns at year 2009 and 2016. Since 2009, there has been an increase in population and traffic demand, including residential areas and industrial facilities. Traffic conditions were improved such as the opening of the highway Inter-Change to Seoul and the construction of underground driveway. As a result, the average vehicle speed increased. More detail comparisons have made on the changes of the underground driveway section and the crossroad section, which are expected to have significant changes in the transportation infrastructure. The vehicle speed distribution of the underground driveway changed from low speed to high speed, and the increase of the time spent at the high speed and high load caused the increase of NOx emissions. The vehicle speed also increased at the crossroad section, and the consequence NOx and $CO_2$ emissions decreased. It is mainly because the decreased time spent at idle, which results from the proper traffic demand management at this area.

• Journal of ILASS-Korea
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• v.19 no.1
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• pp.40-46
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• 2014

Recently rise in oil prices feet the burden on not only diesel vehicle driver but also LPG vehicle driver, and get interested in various way to reduce fuel costs. In this study discuss on exhaust emissions characteristics on driving cycle mode and ignition advance condition change of CNG/LPLI Bi-Fuel vehicle. Experimental test was performed by changing the conditions of fuel (LPG/CNG), spark advance (Base, $10^{\circ}CA$, $15^{\circ}CA$), and driving mode (FTP-75, HWFET, and NEDC). In case of CO emission, in the order of CNG Base, CNG S/A10, S/A15 condition are average reduced -21%, -35%, -29% respectively compared to LPG fuel. The active emission reduction from the initial engine start, spark retard is likely to be beneficial in catalyst warm-up and improve combustion stability rather than spark advance.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.22-28
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• 2005

Exhaust gas emissions from internal combustion engines are one of the major sources of air pollution. And, it is extremely difficult to increase gasoline engine efficiency and to reduce $NO_X$ and PM(particulate matter) simultaneously in diesel combustion. This paper offers some basic concepts to overcome the above problems. To solve the problems, a recommended technique is CAI(controlled auto-ignition) combustion. In this paper, a flame trap was used to simulate internal EGR(exhaust gas recirculation) effect. An experimental study was carried out to find combustion characteristics using homogeneous premixed gas mixture in the constant volume combustion chamber(CVCC). Flame propagation photos and pressure signals were acquired to verify the flame trap effect. The flame trap creates high speed burned gas jet. It achieves higher flame propagation speed and more stable combustion due to the effect of geometry and burned gas jet.

• Particle and aerosol research
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• v.13 no.2
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• pp.43-52
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• 2017

Policy direction for the management of air quality in Korea has been on the reduction of the average concentrations of the criteria air pollutants such as sulfur dioxide and fine particles. However, recently, risk based management of air pollutants becomes an important issue. In this study, to develop an effective air quality management policy direction in Korea, (1) the fourth Multiple Air Toxics Exposure Study (MATES IV) carried out in the South Coast Air Quality Management District (SQAQMD) in the USA is reviewed and (2) the results are compared with in these in Seoul and (3) policy directions are suggested. It was found that (1) systematic integrated study comprising of measurement, modeling, emission inventory estimation, and risk assessment was essential to estimate the health risk of air pollutants reliably, (2) cancer risk of diesel particle was dominant over other air pollutants, and (3) health risk based emissions were different from amount based emissions. It was suggested that (1) reducing the exposure from hot spots might important to reduce health risk from air pollutants and (2) an integrated air quality management administration system is important for the efficient management of air pollution.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.221-226
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• 2018

Despite the increasingly stringent automotive emissions regulations, the impact of vehicle emissions on air pollution remains large. In addition, since the issue of emission of more exhaust gas than the exhaust gas measured in the test room when the vehicle passing the exhaust gas regulation standard is run on the actual road, many countries studied and introduced gas regulations about Real Driving Emission using Portable Emission Measurement System. At present, Korea regulations restrict the number of NOx and PN in diesel vehicles. In the case of gasoline vehicles, there is no regulation on emission gas, but there is a problem of continuing automobile exhaust gas problems and a large amount of gasoline GDI vehicle's PN emission. So research and interest are increasing due to this problem. In this study, characteristics of exhaust gas depending on changes of ambient temperature were analyzed among various factors affecting exhaust gas measurement of gasoline vehicles. As a result, at the low temperature test, the lower the ambient temperature, the more the exhaust gas was emitted. At ordinary temperature test, no specific tendency was observed due to changes of ambient temperature.