• Journal of Power System Engineering
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• v.1 no.1
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• pp.42-51
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• 1997

In this study, in order to investigate the influence of cam profile on the injection rate, the characteristics of injection in PLN (pump - line - nozzle) diesel injection system were simulated. Six types of the profile of fuel cam were used for simulation. The maximum injection pressure and maximum injection rate of initial and end phase were analyzed to demonstrate the characteristics of injection. The mathematical model of the injection system and the computation results were verified by experimental results. Simulation results showed that the maximum injection pressure, maximum injection rate, injection quantity and pressure drop in the end phase were proportional to the velocity of fuel cam during the effective stroke.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.3
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• pp.138-145
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• 2005

Recently, the tightening of an available crude oil supplies has resulted in the development of intense consciousness for saving fuels. At the same time, some research programs have been launched to secure substitute energy sources for petroleum-derived fuels, and to reduce unhealthy products, such as CO, HC, NOx and smoke. To keep up with these trends in society, the regulation affecting diesel smoke may be greatly strengthened in a short time. In not too distant future, LPG and LNG are the most hopeful substitute fuels for automobile and truck uses. This paper discusses how to use such gaseous fuels in a diesel engine, and how much methods for introducing these fuels affect the engine performance.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.249-256
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• 2000

In order to investigate the effectiveness of methanol, which has high latent heat of evaporation and oxygen contents, for DI diesel engine performance and exhaust emission, the methanol was injected at the suction port of DI diesel engine. The injector used for test was conventional gasoline engine injector and controlled the quantity of methanol per cycle by the power supply controller which designed specially for injector. The results shown that the maximum pressure point was delayed, the value of maximum pressure was decreased, and the concentrations of both NOx and Soot were decreased, as the methanol injection quantity increased, and also the thermal efficiency of engine injected methanol under the high load condition was similar to no methanol injection but under the medium load condition was decreased within the experimental conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.28-35
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• 2002

The objective of this paper is to quantitatively investigate the effects of alcohol mixture on the combustion improvement of main fuel in supplying alcohol to direct injection diesel engine by auxiliary injection method and blend method. If alcohol is supplied, engine performance greatly improves in high load range. In case of supplying ethanol, BSFC improves, the emission of smoke and NO decreases by delaying main fuel injection timing 5$\^{C}$A. The maximum delivery quantity of alcohol is limited to approximately 50% of total fuel delivery due to misfire and knocking. The limit quantity of main fuel injection that does not accompany misfire and the deterioration of BSFC was approximately 15∼18.5mg/st.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.75-81
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• 2001

This paper presents the atomization characteristics of single hole injector in the direct injection type diesel engine. The spray characteristics of fuel injector such as the droplet size and velocity were measured by phase Doppler particle analyzer. In this paper, the atomization characteristics of fuel spray are investigated for the experimental analysis of the measuring data by the results of mean diameter and mean velocity of droplet. The effect of fuel injection pressure on the droplet size shows that the higher injection pressure results in the decrease of mean droplet diameter in the fuel spray. The minimum size of fuel spray droplet appears on the location of 40mm axial distance from nozzle exit of diesel injector. Based on the experimental results, the correlation between the droplet diameter and mean velocity of the diesel spray due to the change of axial and radial distance from the nozzle tip were investigated.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1206-1207
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• 2011

하이브리드 발전시스템에서 전압과 주파수제어는 서로 다른 분산전원의 동기화 및 전력제어에 있어서 매우 중요하다. 본 논문에서는 디젤 발전 시스템에서 연료 분사량을 제어하여 주파수를 담당하는 Governor 제어기에 대한 제어 알고리즘을 개발하여 적용함으로써, 연료분사량을 최적화하여 일정한 속도제어를 하고자 한다. 이는 기본 제어기 알고리즘에 전력에 대한 전류 지령치를 첨가함으로서 제어기의 속응성 및 안정도를 개선할 수 있다. 또한 기존 디젤발전기의 부하에 따른 전압 및 주파수 특성을 분석하고, 시뮬레이션 함으로서 본 알고리즘을 검증하였다.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.36-44
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• 2000

In his study the simulation was carried out by simplifing and modeling dividing into fuel injectioin pump high pressure pipe and fuel injection valve in the fuel injection system of a low speed marine diesel engine. A computer simulation model was developed using the method of characteristics to analyze the unsteady flow in the fuel injection system considering cavitation and variation of fuel density and bulk modulus. Comparison was commenced between the calculated data and experimental data of pressure and injection quantity at the high pressure distributor in fuel injection system for the training ship "M/V hanara" the effects of the high pressure pipe length diameter plunger diameter nozzle openning pressure were also investigated by simulating results.g results.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.2
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• pp.137-146
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• 1996

Behaviour of ultra-high pressure diesel spray and its structure in a constant-volume pressure chamber were studied with injection pressure ranging from 35 to 110MPa. Sprays were observed by using the back illumination scattering method and righ angle scattering method. The spray process mechanism were investigated with both photographs. As a result, the spray angle and air entrainment angle was larger as injection pressure and back pressure increase. It becomes clear that mean air-fuel ratio is increased by increasing the injection pressure.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.1
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• pp.41-49
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• 1993

Piston slap is one of the major sources of noise in a 4-cycle diesel engine. Piston slap is not only one of major source mounted near the top and bottom of the piston thrust and antithrust skirts. Effects of engine speed, load and coolant temperature on piston motion were investigated. The measured piston motion showed 6 slapes per cycle resulting from the change of side force. Major piston slap timing was retarded as engine speeds became higher. The increase of engine load made large piston transverse movement toward thrust side of cylinder block. Piston transverse movement was due to reduced piston-liner clearance at higher coolant temperature.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.49-56
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• 1999

The effects of the internal flow in a D.I. Diesel injection nozzle on the atomization of a spray were analyzed experimentally. Flow visualization studies were made using a transparent acrylic model nozzle as a diesel nozzle . Water instead of disel fuel was used as the injection liquid. The geometry of the model nozzle was scaled up 10 times of the actual nozzle and the injection pressure for the model nozzle was adjusted so as to achieve a Reynolds number at the discharge hole that was the same as the actual nozzle. Experimental results show that when the needle lift was small, the high turbulence in the sac chamber generated by the high velocity seat flow made the spread angle of the spray plume large. Cavitation, which arose from the sac chamber, makes the spread angle of the spray plume large but the discharge coefficient small.