• 한국분무공학회지
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• 제1권1호
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• pp.55-62
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• 1996

In a fuel injection engine, atomization of liquid fuel and mixture formation process has influenced(or affected) directly on the engine performance and pollutant emission. In this study, the characteristics of fuel spray and the behaviors of secondary atomization developed at the downstream of the valves were investigated using an image processing method. Solid and perforated valves are chosen in order to evaluate the valve performance in terns of air flow rate, valve opening angle and valve shape. Experimental results clearly indicate that the spray atomization quality can be improved by increasing the perforated rat io and the blockage rat io in the perforated valve, the characteristics of spray atomization is improved by using the perforated valve with high perforated rat io and blockage ratio.

• 한국분무공학회지
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• 제1권2호
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• pp.50-56
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• 1996

In an fuel injection type gasoline engine, atomization of fuel droplet and mixture formation process are very important to understand engine combustion efficiency, and also has influence directly on the decision of engine performance and pollutant emission. In this study, perforated throttle valve instead of solid type throttle valve was developed and equipped to an SPI engine to promote secondary atomization and good droplet-air mixture formation. From the engine performance lest. it was verified that the case of perforated valve kas more advantages in each experimental parameters such as in cylinder gas pressure, mass burnt ratio, fuel consumption rate, and pollutant emission characteristics than that of solid one equipped. No matter what the same perforated valve, there are some distinct results in engine performance characteristics according to the perforate ratio.

• 한국분무공학회지
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• 제1권2호
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• pp.33-41
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• 1996

Mixture formation is one of the important factors to improve combustion performance of MPI gasoline engines. This is affected by spray and atomization characteristics of injector. Especially, in the case of EGI system, air-fuel mixing period is too short and formed a lot of fuel-film in the intake manifold and cylinder wall. This fuel-film is not burnt in cylinder, it is exhausted in the form of HC emission. In this paper, spray characteristics such as size distributions, SMD, and spray angle are measured by PMAS, and the fuel-film measuring device is developed specially. Using this device, the amount and distribution of fuel-film which flows into through valve can be measured Quantitatively. As the result of these experiments, the information of optimal spray characteristics and injection condition that minimize the fuel-film can be built up.

• 한국분무공학회지
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• 제4권2호
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• pp.33-39
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• 1999

This paper presents the spray atomization characteristics of the high-pressure gasoline injector for the direct-injection gasoline engine. The gasoline sprays of the injector were minted into a pressurized spray chamber with a optical access at various ambient pressures. The atomization characteristics of fuel spray such as mean diameter, mean velocity of droplet were measured by the phase Doppler particle analyzer system. In order to investigate the effect of fuel injection pressure on the quantitative characteristics of spray, the global visualization and experiment of particle measurement in the fuel spray were investigated at 3, 5 and 7 MPa of injection pressure under different ambient pressure in the spray chamber. Based on the results of this work, the fuel injection pressure of fuel injector in gasoline direct-injection engine have influence upon distribution of the mean velocity and droplet size of fuel spray. Also, the influence of injection pressure on the velocity distribution at various measuring location were investigated.

• 한국산업융합학회 논문집
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• 제1권2호
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• pp.41-48
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• 1998

This experimental study describes atomization characteristics of spray-spray impingement. Effect of the impingement location and angle on the penetration and the sauter mean diameter of the impinged spray were investigated. Experiment were performed under ranging from 50kPa to 250kPa spray pressure, ranging $30^{\circ}C$ to $135^{\circ}C$ angle on the penetration and free spray. In the case of this experimental, sauter mean diameter $D_{32}$ tends to decrease and duration of film disintegration $t_f$ to decrease, when spray pressure and angle on the penetration is increased. Sauter mean diameter $D_{32}$ were about 20% to be smaller compared with a free spray to jet-jet impingement and 30% to be smaller compared with a free spray to spray-spray impingement.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.52-58
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• 1998

The spray characteristics of air-assisted fuel injection and its effects on the engine combustion was investigated in this study. The atomization characteristics of a Bosch fuel injector inserted into the air-assist adapter were measured using particle motion analysis system. Droplet size decreased with air supplied and fine spray with below $60\mu\textrm{m}$ of SMD was acquired under the conditions of air-assist pressure over 0.5bar. The lean combustion performance of a 1.8L DOHC engine equipped with air-assist adapters was tested on the dynamometer. When the assistant air pressure is 1.0bar, lean limit recorded the highest value, and CO, HC emissions were decreased at the pressure over 1.0bar.

• 한국분무공학회지
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• 제1권4호
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• pp.32-39
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• 1996

Fuel spray in the MPI gasoline injector and its atomization characteristics are investigated with both macroscopic and microscopic visualization systems. The Bosch injector is inserted into an air-assist spray adapter which is designed to be fabricated and assembled easily. particle motion analysis system is used to measure the SMD of injector, where the assistant air pressure is varied from 0.0 to 1.5bar with fuel pressure 2.8bar. Droplet size decreased with higher air pressure and fine fuel spray with below $60{\mu}m$ of SMD is acquired at the assistant air pressure over 0.5bar.

• 한국분무공학회지
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• 제11권4호
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• pp.234-243
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• 2006

Diesel autothermal reforming (ATR) is a chemical process to produce hydrogen for fuel cell applications. Several previous studies were carried out to identify technical issues in diesel reforming. It is hard to vaporize diesel due to its high boiling points. Liquid droplets of diesel result in inhomogeneous fuel mixing with other reactants such as $O_2\;and\;H_2O$, which leads to reduce the reforming efficiency and make undesired coke in reactor. To solve the fuel delivery issue, we applied an ultrasonic device as a fuel injection system. Ultrasonic injector (UI) remarkably enhanced the reforming efficiency. This paper will present the reforming results using UI. And we will discuss about atomization effects of diesel on autothermal reforming reaction.

• 한국분무공학회지
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• 제5권2호
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• pp.68-74
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• 2000

A this experimental study is executed to analyze spray characteristics for air-shrouded injector and 4hole 2spray type injector used in a gasoline engine. Since spray parameters including spray penetration and angle, SMD, and atomization characteristics are very important to increase the engine performance, the image processing algorithm for measuring the non-spherical spray diameter is developed. Spray characteristics of the air-shrouded injector(2hole 2spray) and 4hole-2spray injector are analyzed respectively by this digital image processing method. Effective spray characteristics to injectors is derived from this experimentation and obtained the design guide for gasoline injector.

• 한국분무공학회지
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• 제9권3호
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• pp.1-7
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• 2004

This experiment was undertaken to investigate the atomization characteristics of the low viscosity biodiesel blended fuel and ultrasonic energy added one. Test fuels were conventional diesel fuel and biodiesel fuel. We compared to the characteristics of viscosity and surface tension, SMD between low viscosity biodiesel blended fuel and ultrasonic energy added one. Sauter mean diameter was measured under the variation of the spray distance. Viscosity and surface tension was measured under the variation of the time trace. To measure the droplet size, we used the Malvern system 2600C. Droplet size distribution was analyzed from the result data of Malvern system. Through this experiment, we found that the condition of the ultrasonic energy added situation had smaller Sauter mean diameter of droplet, viscosity and surface tension than that of the conventional situation.