• Journal of Energy Engineering
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• v.17 no.4
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• pp.227-232
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• 2008

Carbon dioxide is considered a major greenhouse gas that contributes to global wanning. $CO_2$ is a major component of the exhaust in the combustion of any hydrocarbon fuel. The regulation for $CO_2$ emission from vehicles has become much more stringent in recent years. These more stringent regulations require vehicle manufacturers to develop alternative fuels that reduce exhaust emissions. This paper evaluated the correlation of $CO_2$ emission and fuel economy in the Gasoline, Diesel, and LPG vehicles according to FTP-75 and NEDC(ECE15+EUDC) driving mode. From this study, we discovered that the decrease rate of $CO_2$ emission is higher for fuels of lower carbon concentration. When the relationship between $CO_2$ emission and fuel consumption rate according to used fuels is expressed as a function, one can find out that they have a high correlation. LPG vehicles produce less $CO_2$ emission than gasoline and diesel vehicles.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.212-220
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• 2018

As increase the number of vehicles, the issue of greenhouse gas that was emitted by them became important. As a result, greenhouse gas (GHG) regulations are being strengthened and efforts are being actively made to reduce greenhouse gas emissions in the automotive industry. In the other hand, regulations for harmful emission of vehicles have been reinforced by step. Especially, the lastly applied step, so called Euro 6, not only decreased NOx limit down to half of Euro 5 but also introduced real driving emission limit for NOx and PN. It is a challenge for manufacturers to meet the recent GHG regulation as well as the latest emission regulation. To overcome these regulations a De-NOx after-treatment system is being applied to diesel vehicles that are known emitting the lowest GHG among conventional internal combustion engines. At the time of the introduction of Euro 6 emission standard in Korea, in the domestic fuel economy certification test, some diesel vehicles emitted more $CH_4$ than Euro 5 vehicles. As a result, it was confirmed that LNT-equipped vehicles emitted a high level $CH_4$ and the level exceeded the US emission standard. In order to determine the reason, various prior literature was investigated. However, it was difficult to find a detailed study on the methane increase with LNT. In this paper, to determine whether the characteristics of vehicles equipped with LNT the affects the above issue and other greenhouse gases, 6 passenger cars were tested on several emission test modes and ambient temperatures with a environment chamber chassis dynamometer. 2 cars of these were equipped with LNT only, other 2 cars had SCR only, and LNT + SCR were applied to remaining 2 cars. The test result shown that the vehicles equipped with LNT emitted more $CH_4$ than the vehicles with SCR only. Also, $CH_4$ tended to increase as the higher acceleration of the test mode. However, as the test temperature decreases, $CH_4$ tended to decreased. $CO_2$ was not affected by kinds of De-NOx device but characteristic of the test modes.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.409-417
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• 2014

Since the oil price has been significantly jumped for recent some years, the diesel engine of the merchant ship has been mainly used the heavy oil of low quality. Thus, it has been often exposed to severely corrosive environment more and more because temperature of the exhaust gas in a combustion chamber is getting higher and higher with increasing of using the heavy oil of low quality. As a result, wear and corrosion of most parts surrounded with combustion chamber is more serious compared to the other parts of the engine. Therefore, an optimum weldment for these parts is very important to prolong their lifetime in a economical point of view. In this study, four types of filler metals such as Inconel 625, 718, 1.25Cr-0.5Mo and 0.5Mo were welded with SMAW and GTAW methods in the forged steel which would be generally used with piston crown material. And the corrosion properties of weld metal, heat affected zone and base metal were investigated using electrochemical methods such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. in 35% H2SO4 solution. The weld metal and base metal exhibited the best and worst corrosion resistance in all cases of filler metals. In particular, the weld metal welded with filler metals of Inconel 718 revealed the best corrosion resistance among the filler metals, and Inconel 625 followed the Inconel 718. Hardness relatively indicated higher value in the weld metal compared to the base metal. Furthermore, Inconel 625 and 718 indicated higher values of hardness compared to 1.25cr-0.5Mo and 0,5Mo filler metals in the weld metal.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.1-6
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• 2024

An easy approach to replacing older diesel engines is to replace them with gas engines using fuels such as CNG or LPG. However, fuels such as LPG have not been applied to large gas engines in many cases, so it is not easy to predict the performance of gas engines based on CNG fuel. Accordingly, in this study, we applied LPG fuel to a CNG-based large gas engine and examined the performance and emission characteristics. In particular, the results were confirmed through tests to see how effective EGR, which is widely used for NOx reduction, is applied. As a result, in the case of LPG, even though the operating conditions were secured to a level that excludes serious knocking, mild knocking at high loads was still found to be more frequent than CNG. However, it was possible to secure an output level similar to CNG in the high-speed range. Efficiency was higher due to a faster combustion speed than CNG, and it was confirmed that it was possible to simultaneously reduce NOx and the frequency of mild knocking through the application of EGR.

• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.15-20
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• 2010

The interest on the utilization of landfill gases and biogases for energy production has been increasing due to environment concerns and global warming caused by burning fossil fuels, renewable nature of these gases. Using those synthesis gases to generate energy with engine encourages more efficient collection reducing emissions into the atmosphere and generates revenues for the operators. However the lower calorific value of synthesis gases than that of LPG or CNG affects the combustion stability and power output. Thus it becomes necessary to address disadvantages involved by studying synthesis gases in technological perspective. This paper discussed synthesis gas as a fuel for 60kW dual-fuel engine to produce power in an effective way. The methane diluted with $N_2$ was used as a fuel and developed ECU and injector driver facilitated the investigations with diesel fuel.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.3
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• pp.287-295
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• 2006

PAHs (Polycyclic Aromatic Hydrocarbons), one of the carcinogenic materials in environment, were investigated in this study. The standardized analysis conditions were tested, and then various factors which affect to the ambient PAHs concentration in Seoul were estimated. Moreover, the emissions of PAHs from major stationary sources were investigated to determine the quantitative relationships between ambient PAHs concentrations and emission sources. From the factor analysis, three factors relevant to the ambient PAHs in Seoul were found. Factor 1 was related to the concentrations of chrysene, pyrene, indeno (1, 2, 3-cd)pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo prerylene which were mainly emitted from gasoline and diesel fueled cars. Factor 2 showed higher loadings in phenanthrene and anthracene which were due to LNG and BC oil combustion in industry and home. And factor 3 included dibenz(a, h)anthracene and acenaphthene which were emitted from open burning and municipal solid waste incineration. Conclusively, all of three factors were consisted in 82% of total variance. The contribution of mobile sources in ambient air in Seoul was estimated at 64%, that of industrial and home sources at 17%, and that of open burning and municipal incineration at 1%.

• Journal of the Korean Institute of Gas
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• v.17 no.1
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• pp.1-6
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• 2013

Using natural gas-hydrogen blended fuel (HCNG) in a heavy duty vehicle is regarded as an alternative to meet reinforced emission regulation compared to a recent direct injection (DI) diesel engine. Hydrogen can lead stable lean combustion even under leaner mixture condition than natural gas, so that improving not only thermal efficiency but also $NO_x$ emissions. In the present study, the feasibility of HCNG engine's commercialization was accessed with HCNG fuel (30% $H_2$ and 70% natural gas) in aspect to the reliability and possibility to reduce $NO_x$ emissions by the level of EURO-VI under various operating conditions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.11
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• pp.1548-1562
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• 2003

This paper is the first of several companion papers which compare the methods of Air-fuel ratio determination. There are many methods which calculate Air-Fuel ratio from exhaust emission. Most of them are based on the simple chemical equations, which use balance of atom, and the error of the calculation is negligible as far as the instrumentation accuracy is guaranteed. They assume homogeneous mixture and complete combustion to the extent of oxygen availability. Because of these simple assumptions, they cannot offer the information about the fuel distribution state and the malfunction of instrument. For these limitations, Eltinge offered new one based on stricter mathematical model. This result coincides with the others very well and gives more information about the mixture state and instrumentation. Consequently this might be a general solution for Air-fuel ratio determination and exhaust composition. The objects of the calculation, however, were not commercial fuels except gasoline and the compensation method of unburned hydrocarbon was not appropriate to recent analyzer. Moreover he did not consider the fuel which contains oxygen, such as methanol, ethanol and blend of gasoline-alcohol. In this paper, Eltinge chart is expanded to the arbitrary fuel composition as the reference exhaust compositions for the purpose of further discussions about Air-fuel ratio determination methods and the charts fur gasoline, diesel, methanol, M85, liquefied petroleum gas(LPG), natural gas(NG), propane, butane are illustrated.

• Asian Journal of Atmospheric Environment
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• v.5 no.2
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• pp.86-96
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• 2011

The positive matrix factorization (PMF2) and multilinear engine (ME2) models have been shown to be powerful environmental analysis techniques and have been successfully applied to the assessment of ambient particulate matter (PM) source contributions. Because these models are difficult to apply practically, the US EPA developed a more user-friendly version of the PMF. The initial version of the EPA PMF model does not provide any rotational capabilities; for this reason, the model was upgraded to include rotational functions in the EPA PMF ver. 2.0. In this study, PMF and EPA PMF modeling identified ten particulate matter sources including secondary sulfate I, vehicle gasoline, secondary sulfate II, secondary nitrate, secondary sulfate III, incinerators, aged sea salt, airborne soil particles, oil combustion, and diesel emissions. All of the source profiles determined by the two models showed excellent agreement. The calculated average concentrations of $PM_{2.5}$ were consistent between the PMF2 and EPA PMF ($17.94{\pm}0.30{\mu}g/m^3$ and $17.94{\pm}0.30\;{\mu}g/m^3$, respectively). Also, each set of estimated source contributions of the PMF2 and EPA PMF showed good agreement. The results from the new EPA PMF version applying rotational functions were consistent with those of PMF2. Therefore, the updated version of EPA PMF with rotational capabilities will provide more reasonable solutions compared with those of PMF2 and can be more widely applied to air quality management.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.915-921
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• 2012

In this study, we propose a new method for estimating the IMEP using difference pressure, which is the pressure difference between the cylinder pressure and the motoring pressure. The estimated IMEP, denoted as $IMEP_{diff}$, optimizes the theoretical IMEP calculation range based on the fact that the difference pressure exists between the start and the end of combustion. $IMEP_{diff}$ is verified to have a high linear correlation with IMEP with $R^2$ of 0.9955. The proposed method can estimate the IMEP with 21% of the cylinder pressure data and 31% of the calculation effort compared to the theoretical IMEP calculation method, and therefore, it has great potential for real-time implementations. The estimation and control performance of $IMEP_{diff}$ is validated by engine experiments, and by controlling $IMEP_{diff}$, the torque variation between the cylinders was reduced.