• International Journal of Automotive Technology
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• v.8 no.6
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• pp.697-704
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• 2007

Recently, a variable valve timing system has been widely adopted in internal combustion engine in order to improve the fuel economy and torque at low engine speed. In addition, it is known that varying valve timing according to the various engine operations could reduce exhaust gas, especially NOx, because of residual gas by valve overlap. In this study, to improve the low exhaust gas and fuel economy at part load condition, the residual gas and back flow of exhaust gas due to valve overlap were calculated computationally. Moreover, the characteristics of engine performances and NOx formations were investigated with the experiment of combination of intake and exhaust valve timing condition. Under these various valve operating conditions, the effects of both the positive valve overlap and negative valve overlap(valve underlap) were examined simultaneously. Finally, the characteristics of cyclic THC emission were analyzed by using Fast Response FID(FR-FID) in the cylinder, intake port and exhaust port positions. Besides, the effect of the different gradients of the valve timing change on engine performance was investigated and an optimum control strategy was suggested.

• Journal of Power System Engineering
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• v.18 no.4
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• pp.52-59
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• 2014

The purpose of this study is to evaluate the performance of after-treatment equipment and thermal storage devices for a heat recovery and combustor-type $CO_2$ generator fuelled a kerosene. To reduce the levels of harmful exhaust gases produced by a $CO_2$ generator, a catalyzed particulate filter(CPF) has been selected as an after-treatment device, by considering back pressure and exhaust gas temperature. The CO conversions of the catalyzed SiC filter(full plugging) were 92%, and the concentration of PM(particulate matter) was near ambient. A thermal recovery device was used to recover 13% of the heat energy from the exhaust gas through heat exchangers installed on the exhaust line of the $CO_2$ generator. 69% of the moisture within the exhaust gases was removed by condensing water, in order to minimize excessive humidity within the greenhouse.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.399-406
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• 2006

The smoke emission of diesel engines is being recognized as one of the major source of the air pollution problems. This study investigates the potential of esterified rice bran oil to reduce smoke emission as an alternative fuel for diesel engines. Because the esterified rice bran oil has approximately a 10.5% oxygen content, the combustion of the diesel engine improved and exhaust smoke decreased. Gas chromatography was used to analyze not only the total amount of hydrocarbon but also the amount of hydrocarbon components from $C_1$ to $C_6$ in the exhaust gas to determine an exact source responsible for the remarkable reduction in the smoke emission. The number of individual hydrocarbon($C_1{\sim}C_6$) as well as the total amount of hydrocarbon of esterified rice bran oil reduced significantly compared to that of hydrocarbon of diesel fuel.

• Special Issue of the Society of Naval Architects of Korea
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• 2017.10a
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• pp.54-58
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• 2017

The vessels which are operated in ECA (Emission Control Area) after $1^{st}$ January 2016 shall be complied with revised NOx emission requirement (Tier III). Effective solutions for NOx emission requirement are SCR (Selective Catalytic Reduction), EGR (Exhaust Gas Recirculation) and Installation of LNG Dual Fuel Engine. This study is considered the design modification as per application of LNG Ready notation. In case of LNG Ready - S notation, the vessel shall be retrofitted the Main engine with Dual fuel engine and LNG Fuel system after delivery. On this paper, the entire process for design modification was explained to meet the requirement for LNG Ready notation.

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.3-15
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• 1993

A multi-cylinder four cycle spark ignition engine equipped with on exhaust gas recirculation(EGR) system to reduce nitric oxide emission and to improve fuel consumption rate has been comprehensively simulated In a computer program including intake and exhaust manifolds. To achieve these goals, this program was tested against experiments performed on a standard production four cylinder four cycle gasoline engine with EGR system. As EGR rate Increased, the maximum temperature of combustion chamber and NO omission concentration decreased under each driving condition. But the emission concentration of CO didn't change much through whole district in spite of the increase of EGR rate. Fuel consumption rate improved under each driving condition according to the increased of EGR rate until 10 percent EGR rate. Therefore the degree of EGR depend not only on the NO emission but also on the economy and the engine performance criteria of the engine.

• Journal of Biosystems Engineering
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• v.34 no.2
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• pp.77-81
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• 2009

Our nature is facing with serious problems related to the air pollution from automobiles in these days. Specially, the exhaust emissions from the diesel engine are recognized as a main cause influencing the environment severly. In this study, the potential possibility of biodiesel fuel is investigated as an alternative fuel for a naturally aspirated CRDi type diesel engine. The smoke emission of biodiesel fuel 5 vol-% was reduced by approximately 40% at 3000 rpm and full load in comparison with diesel fuel. On the other hand, the power, torque and brake specific energy consumption didn't show significant differences. NOx emission of biodiesel fuel was, however, increased compared with commercial diesel fuel.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.84-89
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• 2014

Not only the emission regulation of on-road vehicle engine, but also emission regulation of off-road engine have been reinforced. It is the reason of wide application of emission reduction technology for off-road engines. In this study, optimization of engine parameters (Injector hole number, Injection timing and EGR rate) for reduction of NOx and smoke emissions were conducted by using the analysis of sensitivity and S/N ratio of Taguchi method(DOE). As results, this paper shows optimum value of the parameters for NOx and smoke emission reduction. From the result of reproducibility verification, it is final that the prediction value of NOx and smoke has the error of below 10%. Consequently, the method and results of this study will be used for quantitative reference to EGR control mapping in next study.

• 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.

• Journal of ILASS-Korea
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• v.20 no.1
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• pp.28-34
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• 2015

Recently, some researchers have been carried out risk assessment of vehicles exhaust on human health. Especially, some of VOCs which is non-controlled, was classified to hazardous pollutant, such as 1,3-Butadiene and BTEX(Benzene, Toluene, Ethylbenzene and Xylene). Therefore, the profile on non-controlled pollutant may be needed in the future, because it would be critical data or information to control them. Additionally, with increasing amount of motorcycle, the source profiling is essential for estimating emission factor and amount on motorcycle exhaust. For these, in this study, imported motorcycles (8 vehicles) were selected as a test model while considering the increasing ratio on sales volume between 2013 and 2014; it was also compared with domestic motorcycles on those. The experiment was conducted by driving mode, UDC and ECE+EUDC that made from EURO III. In addition, it was performed at cold start driving mode without effect by displacement, for evaluating only correlation of BTEX with HC. In order to apply the ratio (m,p-Xylene/o-Xylene) as a marker, the ratio was compared with those of tunnel, road side and residential area. As a result, it showed best correlation ($R^2=0.98$) among those. In the future, it has to be considered as a marker for effect evaluation to atmospheric environment by exhaust emission.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.134-134
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• 2010

Recently, the interest of the study about IGCC(Integrated Gasification Combined Cycle), one of New & Renewable Energy technologies, bas been increased due to the United Nations Framework Convention on Climate Change, the Low Carbon Green Growth policy, etc. Also, with this interest of IGCC, the study on the gas turbine utilizing the synthetic gas is performing actively. In the study of the gas turbine characteristic, the power performance and the combustion efficiency are mainly discussed and also the concern about the exhaust gas is being taken care of due to the increasing awareness of the environment. With this, we would like to go over the exhaust gas emission characteristic by the synthetic gas inflow in this test. In order to conduct such a test, we constructed a synthetic gas supplying system to supply the synthetic gases ($H_2$: hydrogen, $N_2$: nitrogen, CO: carbon monoxide, $CO_2$: carbon dioxide, and $H_2O$: steam) quantitatively and this combustion test was conducted by controlling the supplied synthetic gases artificially. The concentration of the exhaust gases appeared variously depending on the differences of the inflow nitrogen amount and the steam amount, whether or not the carbon dioxide flow in and so on. The results of the test can be able to be utilized for the IGCC study by understanding the exhaust gas emission characteristic of the coal gas turbine by synthetic gas composition.