• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.781-787
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• 2014

The dimensionless extinction constants of particulate matter for F-76 diesel and JP-8 aviation fuels were measured at both 633 nm and 853 nm in the transmission cell where the simultaneous gravimetric measurement of PM concentration is compared to the light extinction measurement. For the F-76 diesel PM, the average value of the dimensionless extinction constants at 633 nm was 8.8 whereas that of the dimensionless extinction constants for JP-8 was 9.8 at the same wavelength. As the wavelength is increased to 853 nm, the average value for the F-76 diesel was reduced to 8.2 whereas that for JP-8 was decreased to 8.9.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.181-188
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• 2001

The evaluation of the noise for the an existing engine was carried out to improve the current noise level. The applied techniques were 1m air-borne noise, combustion noise analysis, torsional analysis at the front pulley and sound pressure intensity. In addition, the evaluation of the possibility to the noise reduction by means of wrapping the parts was performed to propose the detailed information in engine design. In view of the obtained results, the following countermeasures were recommended to reduce the current noise level through the above methods. Furthermore, in order to assess the influence of combustion noise on the overall engine noise, the noise test was also performed by the change of intake air temperature up to 5$0^{\circ}C$ in steps of 1$0^{\circ}C$. Finally, the fixed design specifications to reduce the engine noise will be decided in consideration of the test data for proto type engine.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.53-60
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• 2009

In this study, LPG-blended DME fuel was experimentally investigated in CI(compression ignition) engine. In particular, performance, emissions characteristics (including hydrocarbon, CO, and NOx emissions), and combustion stability of engine fueled with LPG-blended DME fuel were examined. The extent of LPG fuel in the blended fuel was 0-40 wt%. Results showed that stable engine operation was possible in a wide range of engine loads on DME blended with maximum 30% of LPG by mass in a CI engine. Considering the results of the engine power output and exhaust emissions, blended fuel up to 30% of LPG by mass can be used as an alternative to diesel in a CI engine. LPG blended DME fuel is expected to have potential for enlarging the DME market.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.5
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• pp.178-187
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• 1997

For the experimental measurement of heat flux of DI diesel engine combustion chamber, the instantaneous temperature probes and data acquisition system were developed. By the analysis of measured temperatures at the cylinder head, the temperature at the point 3 which is located between intake and exhaust valve was higher than that of the other points. Temperatures at the point located mear the exhaust valve were higher than those of intake valve. The instantaneous and mean temperature at the cylinder head increases proportionally to the increase of the engine speed, while the temperature swing varies inversely. Temperature swings have influence on the maximum heat flux values from gas into head surface. It has been verified that these probes and data acquisition system perform well by the comparison of the trend of instantaneous temperature variation with that of measured combustion chamber pressure variation with respect to crank angle. It is presumed that these probes could be used in the measurement of other parts of combustion chamber as piston, cylinder wall etc. for the future study.

• Journal of Power System Engineering
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• v.19 no.2
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• pp.64-69
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• 2015

Marine diesel engines with high thermal efficiency and fuel diversity used for propulsive power have been taking charge of important position on marine transport. However, marine environment has recently focused on emissions such as nitrogen oxide and sulfur oxide which is generated from combustion of low grade fuels. EGR(Exhaust gas recirculation) system is one of effective methods to reduce the nitrogen oxide emission from marine diesel engines. In general, it is considered that recirculating gas influences fuel combustion and emissions in diesel engines. However, along with positive effects of EGR, the EGR system using fuels of including high sulfur concentration should be considered about re-combustion and activation of sulfur dioxide in recirculating gas. Therefore, in experimental study, an author investigates effects of sulfur dioxide mixture concentration in intake air on combustion and exhaust emission characteristics in a direct injection diesel engine. In results, change of sulfur dioxide concentrations in intake air had negligible impact on combustion chamber pressure, rate of heat release and emissions compared with effects of oxygen decreasing and carbon dioxide increasing of EGR.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.308-315
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• 2013

Water emulsion technology has the problem of unstable combustion due to the rapid separation of water. To solve the problem, a hybrid mixing device was developed. The device attached on the burner was tested. As a result, the fuel consumption reduced to 12% in the similar condition of exhaust emissions and flame temperature, and 45.5%, 98.5% and 97.2% of NOx, CO, and smoke were reduced at the same inlet air and fuel flow rate.

• Tribology and Lubricants
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• v.24 no.4
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• pp.196-204
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• 2008

In this study, the pressure distributions on the oil film of piston pin bearings are found by two-dimensional lubrication analysis in order to help the optimum design of the bearings of piston pin. The lubrication analysis is carried out together with an equation related with the oil pressure-viscosity index. The oil film pressure distribution is used as an input data for pressure boundary conditions at the piston pin-boss surface. Finally, the piston pin-boss stress distribution coupled with the thermal stress is calculated, and then compared with the results of the stress analysis which is not counted with the oil film pressure boundary condition.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.2
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• pp.114-121
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• 2009

There are increased in using the bio-ethanol, as the carbon neutral attracts many researchers due to a reduction in carbon dioxide spotted as the global warming gas. A gasoline engine with 100% of the bioethanol was developed and used in Brazil already, but researches of using the bio-ethanol in diesel engines are lack. In this study, combustion tests with blend fuel of the gas oil and bio ethanol by 50% maximally due to a low cetane number of bio-ethanol were accomplished as a basic study of introduction of using the bioethanol in diesel engines. The result was that smoke emission was decreased with increase in proportion of the bio-ethanol, due to the increase of a amount of pre-mixed combustion with ignition delay. Although the amount of $CO_2$ is reduced according as the bio-ethanol is used(carbon neutral), the emission of $CO_2$ with increase in the proportion of the bio-ethanol was more increased due to lower a heat value of bio-ethanol than gas oil.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.6
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• pp.91-97
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• 2010

This paper described the effects of DME blended fuel on the engine combustion and emission characteristics of four cylinder CRDI diesel engine. Biodiesel was added into the DME fuel in order to improve the low kinematic viscosity of DME fuel. In this work, the experiment was performed under th various injection timings and injection strategy at constant engine speed and engine load. To maintain the fuel pressure and temperature, pressure and temperature controllers were installed to the DME fuel system. The results show that ignition delay was shortened and combustion duration was extended when DME blended fuel is supplied. Despite of slightly higher NOx emission with DME blended fuel at equal conditions in comparison with those of diesel fuel, the engine showed lower HC and CO emission characteristics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.156-160
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• 2006

This study investigated the characteristics of spray generated by a liquid-liquid co-axial swirl injector used in a combustor of the liquid rocket engine. The linear stability analysis[1] was introduced In liquid sheet breakup and Post[2]'s collision model which considers shattering was adopted on the collision model after breakup. Every model was implemented to KIVA[3], which was adopted as solve. To validate the implemented models the cases of high and low injection velocity were calculated respectively and each result agreed well with test results.