• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.131-136
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• 2012

This paper investigated the combustion and exhaust gas characteristics of gasoline direct injection engines for various cooling water temperature. The engine-out nanoparticle emission number and size distribution were measured by a DMS-500 equipped upstream of the catalyst. A CLD-400 and an HFR-400 were equipped at the exhaust port to analyze the cyclic NOx and total hydrocarbon emission characteristics. The results showed that the nanoparticle emission number greatly increased at low coolant temperatures and that the exhaust mainly contained particulate matter of 5.10 nm. THC also increased under low temperature conditions because of fuel film on the combustion chamber. NOx emissions decreased under high temperature conditions because of the increase in internal exhaust gas recirculation. In conclusion, an engine management system control strategy for driving coolant temperature up rapidly is needed to reduce not only THC and NOx but also nanoparticle emissions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.12
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• pp.1691-1698
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• 2003

In this paper, the combination effects of oxygen component in fuel and exhaust gas recirculation on the exhaust emissions have been investigated for a direct injection diesel engine. It is a kind of effective oxygenated fuel of diether group that the smoke emission of DGM(diethylene glycol dimethyl ether) blended fuel is reduced remarkably compared with commercial diesel fuel, that is, it can supply oxygen component sufficiently at higher loads and speeds in diesel engine. But, NOx emission of oxygenated fuel was increased compared with commercial diesel fuel. Also, the effects of exhaust gas recirculation(EGR) on the characteristics of NOx emission has been investigated. It was found that simultaneous reduction of smoke and NOx was achieved with oxygenated fuel(DGM 5vol-%) and cooled EGR method(10∼15%).

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.9-10
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• 2005

A study on the combustion and exhaust emissions characteristics by using Emulsion Fuel in Diesel Engine is performed experimentally. In this paper, the experiments are performed at engine speed 1800rpm, emulsion fuel ratio is 0%, 5%, 10%, 15%, 20%, 25%, and main measured items are specific fuel consumption, NOx and Soot emissions etc. The obtained conclusions are as follows. 1) Specific fuel consumption increase maximum 19.8% at low load, but is not effected at full load. 2) NOx emissions decrease 30% in case of emulsion fuel ratio 25% at full load. 3) Soot emission decrease 58.9% in case of emulsion fuel ratio 25% at full load.

• Journal of Power System Engineering
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• v.8 no.1
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• pp.18-23
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• 2004

The direct injection diesel engine is one of the most efficient thermal engines. For this reason DI diesel engines are widely used for heavy-duty applications. But the world is faced with very serious problems related to the air pollution due to the exhaust emissions of diesel engine. So, that is air pollution related to exhaust gas resulted from explosive combustion should be improved. Exhaust Gas Recirculation(EGR) is a proven method to reduce NOx emissions. In this study, the experiments-were performed at various engine loads while the EGR rates were set from 0% to 20%. The emissions trade-off and combustion of diesel engine are investigated. Hot and cooled EGR are achieved without cooling and with cooling respectively. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke emissions. Also, the reduction rates of NOx emissions for hot and cooled EGR are similar at load 20%.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.1
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• pp.44-50
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• 2007

Diesel engines have high thermal efficiency, and they have less CO & HC emissions than another engines. while NOx & Soot emissions are very much. compared with exhaust emission standards. However, the limit level is more and more strengthened yearly due to the importance of environmental protection. So, the optimal countermeasures for the reduction of NOx & Soot emissions below limit level are required. Therefore. the author has investigated the effects of emulsified fuel on the characteristics of exhaust emissions. using an four-cycle, four-cylinder and direct injection diesel engine because the using of emulsified fuel among various methods for reducing NOx & Soot emissions is simple in installation low in cost and high in efficiency. The results of investigation according to various operating conditions are as follows : 1) Specific fuel consumption increase maximum 19.8% at low load. but is not affected at full load. 2) In case of emulsion ratio 25%, NOx emission decrease 32% at 75% load. 30% at full load. 3) In case of emulsion ratio 25%, Soot emission decrease 84% at 75% load, 59% at full load.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.317-318
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• 2015

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.7
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• pp.603-610
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• 2016

This paper describes experimental results about emission and NOx reduction of dilution effect (Nitrogen and carbon dioxide) about various fuel compositions of synthetic natural gas (SNG). Combustion experiment was performed to investigate the combustion characteristics for SNG with various hydrogen ratio in SNG, heat input and equivalence ratio in a partially premixed model gas turbine combustor. NOx emission was similar to each hydrogen ratio and flame characteristics was investigated from OH chemiluminescence images. There was a singularity of CO emission in stoichiometric condition and it can be identified using OH chemiluminescence intensity. In addition, dilution effect was studied in using nitrogen and carbon dioxide as diluent to reduce the NOx emission. Carbon dioxide diluent was more effective to NOx reduction than nitrogen diluent because of its high diluent specific heat and its heat capacity.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.2
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• pp.106-114
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• 1996

Extensive experiments were conducted to investigate the emission of DI diesel engine by using DMC(dimethyl carbonate) as an oxygenated fuel additives. The results indicate that smoke reduces almost linearly with fuel oxygen contents. Reductions of HC and CO were attained noticeably, while a small increase in NOx was encountered concurrently. The effective reduction in smoke with DMC was maintained with the presence of CO2, which suggested a low NOx and smoke operation could be obtained in combination of using oxygenated fuel and EGR. Further experiment was conducted a thermal cracking set-up for mechanism studies.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1081-1086
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• 2014

An experimental study was performed in order to compare with the case of using pure diesel the characteristics of combustion pressure and exhaust emissions when the engine speed was changed in a CRDI 4-cylinder diesel engine using biodiesel( Canola oil) blended and pure diesel fuel. As a results, the combustion pressure was decreased with increasing biodiesel blended rate when engine speed was 1,000, 1,500, 2000(rpm). but the combustion pressure of the engine speed 2,500rpm was increased with increasing biodiesel blended rate. The emission results show, that CO was decreased with increasing biodiesel blended rate and engine speed. The emission of $CO_2$, NOx, were increased with increasing biodiesel blended rate and engine speed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.7
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• pp.818-825
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• 2004

In this paper, the study of effects of flow parameters on flame structure and NOx emission concentration was performed in co-axial. laminar partially premixed methane/air flames. Such (low parameters as equivalence ratio(${\Phi}$), fuel split percentage($\sigma$), and mixing distance(x/D$\_$i/) were defined as a premixing degree and varied within ${\Phi}$=1.36∼9.52, $\sigma$=50∼100, and x/D$\_$i/=5∼20. The image of OH$\^$*/ and NOx concentration were obtained with an ICCD camera and a NOx analyzer. The flame structure observations show a categorization of partially premixed flames into three distinct flame regimes corresponding to ${\Phi}$<1.7(premixed flame structure), 1.7<${\Phi}$<3.3(hybrid structure), and ${\Phi}$>3.3(diffusion flame structure existing a luminous sooting region) at $\sigma$=75%, and x/D$\_$i/=10. As o decreases from 100% to 50%, and x/D$\_$i/ decreases, nonpremixed flame structure appear at low equivalence ratio relatively. In addition, the measured emissions for NOx rise steeply from ${\Phi}$=1.7, to ${\Phi}$=3.3, then constants ${\Phi}$>4.76. NOx emissions decrease with increase the level of premixing level. In conclusion, the main effect on flame structure and NOx production was at first equivalence ratio(${\Phi}$), and next fuel split percentage($\sigma$), and finally mixing distance(x/D$\_$i/).