• Journal of ILASS-Korea
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• v.6 no.3
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• pp.32-37
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• 2001

The characteristics of engine performance with fuel injection system in D.I. diesel engine were studied in this paper. A fuel injection system has an important role in the performance and emission gas in a diesel engine. In this paper, an experimental study has been performed to verify the effect of the performance and the emission gas with the factors such as diameters of an injection nozzle hole, diameters of an injection pipe and injection timing in the fuel injection system. The authors have obtained the results that optimizing the factors of fuel injection system is significant to enhance the performance of the engine system and consumption ratio of fuel, smoke, and NOx.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.645-652
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• 2010

The aim of this investigation was study on the non-evaporation diesel spray characteristics injected through a common-rail diesel injector under various ambient pressure. The diesel spray was investigated with observation of macroscopic characteristics such as spray tip penetration and spray cone angle by the shadowgraph and the image processing method. The numerical study was conducted using a computational fluid dynamics code, AVL-FIRE. The breakup models used were WAVE model and standard $k-{\varepsilon}$ turbulence model was applied. The numerical study used input data which spray cone angle and fuel injection rate was achieved by Zeuch's method. Comparison with experimental result such as spray tip penetration was good agreement. Distribution of droplet diameter were conducted on four planes where the axial distances were 5, 15, 39 and 49mm respectively downstream from the orifice exit.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.180-184
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• 2016

Legislative and regulatory actions regarding the exhaust gas from ships are being strengthened by both international organizations and national governments, to protect human health and the environment. Exhaust gas traps are excluded from exhaust gas regulation applications, but, recently, the United States, Britain, and other developed countries have examined a variety of ways to improve the system, including the introduction of electric propulsion systems to prevent air pollution generated by naval ships. This study investigates a large number of smoke problems of naval diesel engines to verify the effect of improving the nozzle characteristics. An exhaust gas emission measurement method to determine the quality of pollutant exhaust gas generated during low-load operation is proposed through the research methodology of the smoke problem. It was confirmed that the emissions value is improved by decreasing the nozzle hole diameter and increasing the injection pressure. At the same time, the flow rate decrease equation and setting up a test memo based on the nozzle diameter confirmed that the fuel consumption, to which the nozzle diameter in the flow path is related, is reduced.

• Journal of Energy Engineering
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• v.11 no.2
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• pp.90-98
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• 2002

The effects of swirl and combustion parameters on the performance and emission in a turbo-charged D.I. diesel engine of the displacement 9.4L were studied experimentally in this paper. Generally the swirl in the combustion process of diesel engine promotes mixing of the injection fuel and the intake air. It is a major factor to improve the engine performance because the fuel consumption and NO$_{x}$ is trade-off according to the high temperature and high pressure of combustion gas in a turbocharged D.I. diesel engine, it's necessary to thinking over the intake and exhaust system, the design of combustion bowl and so on. In order to choose a turbocharger of appropriate capacity. As a result of steady flow test, when the swirl ratio is increased, the mean flow coefficient is decreased, whereas the gulf factor is increased. Also, through engine test its can be expected to meet performance and emissions by optimizing the main parameter's; the swirl ratio is 2.43, injection timing is BTDC 13$^{\circ}$ CA, compression ratio is 16, combustion bowl is re-entrant 5$^{\circ}$, nozzle hole diameter is $\Phi$0.28*6, turbocharger is GT40 model which are compressor A/R 0.58 and turbine A/R 1.19.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.12
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• pp.1489-1495
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• 2013

High-pressure flows are ubiquitous in many industrial fields. A representative application is fuel injection using a common-rail control system in diesel engines, where the injection pressure in the injector exceeds 1000 bar. In high-speed injection, the fluid injected through the nozzle undergoes breakup owing to the interaction with the ambient gas. The breakup process influences mixture formation, which in turn influences combustion in diesel engines. Therefore, it is very important to analyze the breakup process of fuel spray. The Reitz and Diwakar model and cascade atomization and breakup (CAB) model were used in this study as sub-models for the numerical analysis of the breakup process of fuel spray. This study aims to precisely analyze the breakup process of spray and to investigate the breakup frequency of the injected fuel. Consequently, it proposes a suitable sub-model for analyzing the breakup process of a diesel spray by using CFX, a commercial CFD program.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.11-18
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• 2001

To clarify the influence of SAC shape of hole-type diesel nozzle on injection characteristics and spray patterns, the injection rate of three nozzle types(standard SAC nozzle, Needle-cut VCO nozzle and VCO nozzle) were measured by Zeuch's method and pictures of the sprays were taken by CCD camera. As the pump speed became higher, the injection characteristics of the three nozzles were different. Injection rate and perssure curves at the high pressure pipe in Needle-cut VCO nozzle were much more similar to the VCO nozzle than those of the SAC nozzle. When the needle was at pre-lift period for all speeds, the spray of the Needle-cut VCO nozzle showed almost the same shape as the SAC type nozzle. There was no differense in spray pattern at the needle full-lift periods.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.160-170
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• 1997

The objective of this study is to investigate the atomization characteristics and the performance characteristics of a C. I. engine by using the changes of the injection nozzle type and the ultrasonic-energy-added system. In order to evaluate the effect of ultrasonic energy and of change of injection nozzle type in the performance characte- ristics of a diesel engine, measurements of droplet size of diesel fuel were carried out by using Malvern system. In all types of injection nozzles, SMD of the ultrasonic- energy -added diesel fuel was smaller than that of the conventional diesel fuel and the more injection pressure increased, the more SMD decreased. There was a small increase in SMD with the distance from injection nozzle under all conditions of the injection nozzle types. The minimum SMD was found in the injection nozzle of B type. In the diesel engine test, there were three results about the engine performance. Compared with the injection nozzle of A type, B type had excellent effects in the engine performance. The most excellent effects about the engine performance were obtained in the case of ultrasonic-energy-added diesel fuel. In addition, the torque diagram in the case of ultrasonic-energy-added diesel fuel was more stable and periodical than others.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.7
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• pp.1123-1130
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• 2004

Numerical simulations have been carried out to investigate the effect of nozzle hole geometry on the combustion characteristics of the large diesel engine. 6S90MC-C. Spray and combustion phenomena were examined numerically using FIRE code. Wane breakup and Zeldovich models were adopted to describe the atomization characteristics and NOx formation processes. Predictions on the cylinder peak pressure and NOx emission were first verified with the experimental data to confirm the reliability of numerical calculations. The comparison results showed good agreements within the range of 0.64% and 4.6% respectively. Finally, the effects of fuel spray angle and diameter on the engine performance were investigated numerically to find the optimum nozzle hole geometry considering fuel consumption, NOx emission and heat flux of the combustion chamber wall. It was concluded that the combustion gas recirculation in cylinder by changing fuel injection direction is an effective method to reduce NOx emission by about 10% with increasing fuel oil consumption, 1.4% in a large diesel engine.

• Journal of ILASS-Korea
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• v.12 no.3
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• pp.154-159
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• 2007

Spray tip penetration and spray angle for one main injection were measured at the atmospheric condition with the fuel injection pressure of 270 bar and 540 bar. It investigates an effect of different nozzle hole geometry of conventional cylindrical one and those of elliptical ones. Injection period represented by injector pulse drive was fixed at 1ms. From the result of this study, it is shown that spray tip penetration becomes shorter and spray angle becomes wider with the elliptical nozzle hole geometry due to fast break-up of a fuel liquid column.

• Journal of ILASS-Korea
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• v.7 no.2
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• pp.16-21
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• 2002

Liquefied petroleum gas (LPG) has been used as motor fuel due to its low emissions and low cost. This study addresses the analysis of the LPG spray behavior near injection nozzle. The LPG spray photographs are compared with sprays of diesel fuel at the same conditions. The LPG spray photos show that the dispersion characteristic depends very sensuously on the ambient pressure soon after injection. The spray angle is very wide in a low ambient pressure condition until the saturated pressure at this test condition, but the angle value is quickly reduced at the condition over the pressure.