• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.74-80
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• 2007

An experiment was conducted with a common-rail direct injection diesel engine operated with neat dimethyl ether (DME). In order to investigate the effect of combustion characteristics and emission reduction of DME fuel, the experiment was performed at various injection pressure from 35 MPa to 50MPa. Also, the exhaust emissions from the engine were compared with that of diesel fuel. In this work, Cooled EGR was implemented to reduce $NO_x$ exhaust emissions. The results showed that DME has shorter ignition delay than that of diesel fuel. Despite of the increased $NO_x$ emissions with DME at an equal engine power compared to the case of fueling diesel, the engine emitted zero soot emissions all over the operating conditions in this work. $NO_x$ emission can be decreased greatly by adopting 45% of EGR while maintaining zero soot emission. Judging from the result of engine test, DME is a suitable fuel for common-rail diesel engine due to it's clean emission characteristics.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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• pp.443-454
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• 1998

Pt-V catalytic converter was installed on a heavy duty diesel engine and the characteristics of the emission reduction were tested using a engine dynamometer at various operating conditions. The emission reduction performance of Pt-V catalyst was also compared with that of a commercialized Pt catalyst currently being used in some of the heavy duty diesel engines in advanced countries. The effects of Pt-V and Pt catalysts on regulated and unregulated emissions were investigated using a 0.05 weight percent sulfur content fuel with an engine dynamometer Experiments for gaseous emissions (CO, HC and aldehyde) as well as particulate emissions (TPM, SOF and sulfate) have been conducted at several operating conditions such as T-7 mode, D-13 mode and S-13 mode before and after installing the Pt-V and Pt catalysts in the exhaust system. The emission reduction performance of Pt catalyst with respect to CO, HC, SOF, PAHs and aldehyde was found to be a little higher than that of Pt-V catalyst, but the Pt catalyst showed innate disadvantage of causing an increase of PM due to the sulfate formation via high SO2 conversion at high exhaust temperature, especially above 45$0^{\circ}C$.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.158-165
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• 2008

The combustion and exhaust emissions characteristics of a liquefied petroleum gas-di-methyl ether compression ignition engine with a variable valve timing device were investigated under various liquefied petroleum gas injection timing conditions. Liquefied petroleum gas was used as the main fuel and was injected directly into the combustion chamber. Di-methyl ether was used as an ignition promoter and was injected into the intake port. Different liquefied petroleum gas injection timings were tested to verify the effects of the mixture homogeneity on the combustion and exhaust emission characteristics of the liquefied petroleum gas-di-methyl ether compression ignition engine. The average charge temperature was calculated to analyze the emission formation. The ringing intensity was used for analysis of knock characteristics. The combustion and exhaust emission characteristics differed significantly depending on the liquefied petroleum gas injection and intake valve open timings. The CO emission increased as the intake valve open and liquefied petroleum gas injection timings were retarded. However, the particulate matter emission decreased and the nitrogen oxide emission increased as the intake valve open timing was retarded in the diffusion combustion regime. Finally, the combustion efficiency decreased as the intake valve open and liquefied petroleum gas injection timings were retarded.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.448-453
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• 2003

In this study, the effects of oxygen component in fuel and exhaust gas recirculation(EGR) method on the exhaust emissions has been investigated for a D.I. diesel engine. It was tested to estimate change of exhaust emission characteristics for the commercial diesel fuel and oxygenate blended fuel which has five kinds of blending ratio. Dimethoxy methane(DMM) contains oxygen component 42.5% in itself. and it is a kind of effective oxygenated fuel for reduction of smoke emission. It was affirmed that smoke emission was decreased with increasing of DMM blending ratio. But, NOx emission was increased compared with commercial diesel fuel. It was needed a NOx reduction countermeasure that EGR method was used as a countermeasure for NOx reduction. It was found that simultaneous reduction of smoke and NOx emission was achieved with DMM blended fuel and cooled EGR method($10{\sim}15%$).

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.392-397
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• 2001

As the air pollution caused by diesel vehicles goes worse, so non-road vehicles exhaust gas standard is strict in an foreign countries. In this paper, we calculate the amount of emission rates from Korean railroad lines and train kinds. Air pollutants emissions are calculated using by US EPA baseline in-use emission rates which is divided line-haul and switch mode. The calculated HC emissions on the railroad diesel vehicles are 1,209.1 t from Korean railroad lines.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.115-120
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• 2001

The present study examined the possibility of $NO_{x}$ reduction in the high temperature industrial furnaces. duct burner of gas turbine cogeneration and two-stage gas turbine combustor. The experimental study was carried out for the diffusion flame of second stage combustor with the variations of oxygen concentration and supplying rate of hot exhaust gas from first stage combustor. It also examined the flammability range and $NO_{x}$ formation of the second stage combustor in which the fuel is supplying into the mixture of oxygen hot exhaust gas from first stage combustor. The results show that the enrichment of oxygen and increase of exhaust gas lead to increase the $NO_{x}$ up to 50 ppm with 23% $O_{2}$ condition.

• Journal of ILASS-Korea
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• v.23 no.1
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• pp.1-8
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• 2018

In this study, the effects of variation in cam phasing and valve lift of exhaust valves by using Cam-in-Cam system on combustion and emission characteristics for diesel engine were investigated under GT-POWER simulation environment. This paper showed analytic result of combustion characteristics and diesel exhaust valve's control with GT-Power 1-D detail model. As a result, it was found that volumetric efficiency and IMEP were decreased as the exhaust valve opening and closing timing is advanced due to its internal EGR effects. Also, it was found that NOx emission were decreased as EVC timing was retarded. These show that the retarding the exhaust valve closing and opening while keeping the duration at constant can be effective for controlling AFR and mixing rate in diffusion combustion of diesel engine.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.526-534
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• 2000

In this study, the characteristics of exhaust emissions in medium speed diesel engine under various operating conditions were investigated through experiments to derive the optimum conditions for minimizing the exhaust emissions, especially, nitrogen oxides. The 355 KW$\times$1200 rpm medium speed diesel engine was intensively examined to investigate the trend of exhaust emissions in case that the parameters affecting combustion conditions such as fuel injection timing, intake air temperature and pressure, engine speed and load were changed. The exhaust emissions for 9 sets of medium speed diesel engine were analyzed in addition. From this study, NOx level could be reduced by 30~50% through the adjustment of retarded fuel injection timing, lowered intake air temperature and increased charging air pressure.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.114-120
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• 2011

Fuel reforming technology for the fuel cell vehicles has been frequently applied to internal combustion engine for the reduction of engine out emissions. Since syngas which is reformed from fossil fuel has hydrogen as a major component, it has abilities to enhance the combustion characteristics with wide flammability and high speed flame propagation. In this paper, syngas was feed to a 2.0 liter SI engine with MPI to improve exhaust emissions under cold start and early state of idle condition. Syngas fraction is varied to 0%, 10%, 25%, with various ignition timings. Exhaust emission characteristics and the exhaust system temperature were measured to investigate the effects of syngas addition on cold start. Result showed that HC emission could be dramatically reduced due to the fact that syngas has $H_2$ and no HC as components. The amount of $NO_x$ emission was decreased with the increase of syngas fraction. Because the dilution effect of $N_2$ and the retard of ignition timing reduces the peak combustion temperature inside the cylinder. Exhaust gas temperature was lower than that of gasoline feeding condition. Retarded ignition timing, however, resulted in increased exhaust gas temperature approximated to gasoline condition. It is supposed that the usage of syngas in an SI engine is an effective solution to meet the future strict emission regulations.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.4
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• pp.234-244
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• 2014

Recently it has been focused that the automobile engine has developed in a strong upward tendency for the use of the high viscosity and poorer quality fuels in achieving the high performance, fuel economy, and emission reduction. Therefore it is not easy to solve the problems between low specific fuel consumption and exhaust emission control at motor cars. In this study, it is designed and used the engine test bed which is installed with turbocharger and intercooler. In addition to equipped using CRDI by controlling injection timing with mapping modulator, it has been tested and analyzed the engine performance, combustion characteristics, and exhaust emission as operating parameters, and they were engine speeds(rpm), injection timing(bTDC), and engine load(%). From the result of an experimental analysis, peak cylinder pressure and the rate of pressure rise were increased, and the location of it was closer toward top dead center according to the increasing of engine speed and load, and with advancing injection timing. The combustion characteristics are effected by fuel injection timing due to be enhanced the mass burned fraction. Using the engine dynamometer for analyzing the engine performance, the engine torque and power have been enhanced according to advancing the fuel injection timing. In analyzing of exhaust emission, there has been a trade-off between PM and NOx with increasing of engine speed and load, and with advanced injection timing. The experimental data are shown that the formation of NOx has increased and PM, vice versa.