• Journal of ILASS-Korea
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• v.27 no.4
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• pp.173-180
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• 2022

Cooling fog is being used in various parts of society such as fine dust reduction, cleanliness, and temperature drop. Cooling fog has the advantage of low flow rate and ease of use compared to other spray systems. In the case of cooling fog, it was confirmed that the injection angle increased as the pressure increased and the nozzle diameter increased. In this study, the minimum injection angle was 33.61 degrees and the maximum injection angle was 107.38 degrees. It was confirmed that the larger the nozzle diameter and the smaller the pressure, the larger the droplet size. In addition, it was confirmed that the Sauter Mean Diameter (SMD) increased along the X and Y axis directions. It was confirmed that the size of the droplet decreases as it approaches the nozzle tip due to the characteristics of the nozzle design factor.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.162-173
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• 1998

The high pressure common rail injection system offers a high potential for improving emmisions and performance characteristics in large direct diesel engines. High pressures in the common rail with electronic control allows the fuel quantity and injection timing to be optimized and controlled throughout a wide range of engine rpm and load conditions. In this study, high pressure supply pump, common rail, pipes, solenoid and control chamber, and nozzle were modeled in order to predict needle lift, rate of injection, and total injected fuel quantity. When the common rail pressure is raised up to 13.0 ㎫ and the targer injection duration is 1.0ms, the pressure drop in common rail is about 5.0㎫. The angle of effective pressurization is necessary to be optimized for the minimum pump drive torque and high pressure in common rail depending on the operating conditions. The characteristics of injection were also greatly influenced by the pressures in common rail, the areas of the inlet and exit orifice of the control chamber.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.12 no.1
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• pp.1-6
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• 1976

To investigate the relation of $NO_x$ emission and consumption rate in a direct injection diesel engine with a multihole nozzle under same fuel consumption and rpm, a naphthyl ethylenediaming method on NO, emission and Tektronix oscilloscop on the indicator diagrams have been used. Comparisons of the $NO_x$ emission and fuel consumption rate made on various conditions have led to the fllowing results. 1. The higher the injection pressure in the later injection time the lower $NO_x$ emission and the fuel consumption rate have been attained. 2. By the change of nozzle hole diameter under the same injection pressure, the $NO_x$ emission was much more lowered in the small diameter than large one, but fuel consumption rate was in inverse proption to the $NO_x$ emission. 3. The effect of injection spray angle, $\frac{1_n}{d_n}$ on $NO_x$ emission, fuel consumption rate under same injection time and injection pressure was neglectable.

• International Journal of Automotive Technology
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• v.6 no.1
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• pp.9-14
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• 2005

An experimental investigation has been carried out to reveal the atomization process of the diesel fuel spray. The spray injected through a single hole nozzle was taken by a camera on the opposite side of a stroboscope for macroscopic observation or a nanolite for microscopic observation. The effect of nozzle aspect ratio was analyzed with disintegration phenomena of the diesel spray. Based on the enlarged spray photograph, atomization process was observed in detail and further the spray cone angle was measured under various ambient pressures. The result shows that atomization of diesel spray in early stage of injection is mainly progressed in the vicinity of spray periphery region except the region close to the nozzle exit and spray head region. The spray cone angle is nearly constant under the pressurized condition, while it decreases with elapsing time under the atmospheric condition.

• Journal of ILASS-Korea
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• v.6 no.4
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• pp.39-48
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• 2001

The Gasoline Direct Injection(GDI) system has been highlighted due to the improvement of fuel consumption and the control of exhaust emission from gasoline engines. Main purpose of the present study is to measure spray characteristics of GDSI for real engine application. We have investigated experimentally spray tip penetration, spray angle, tip velocity and spatial spray distribution. Counter-rotating vortex grown on the spray surface plays an important role in the spray characteristics. Accordingly the spray tip penetration and tip velocity do not excess 50mm, 20m/s respectively, under 0.6MPa ambient pressure. the spray cone angle of GDSI have a same tendency to a simplex swirl atomizer.

• Journal of ILASS-Korea
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• v.6 no.3
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• pp.17-22
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• 2001

Recently LPG engine is developed to fulfill such new requirements as improved fuel efficiency in additional to further reduced exhaust emission. This experimental study is conducted to analyze spray characteristics for pintle type injector used in a LPLi (Liquid Phase LPG injection) engine. Since spray parameters including penetration length and spray angle make a role to design injector and engine intake system, spray visualization experiment is performed under atmosphere ambient and charging condition using Mie scattering method. From the experimental result under various LPG formation, the increased propane component decreases penetration length because boiling point of propane is lower than butane. To simulate intake charging condition in MPI engine, spray visualization is performed under high pressure condition. As a result, as ambient pressure is increased from atmosphere to 3.0 bar, penetration length is decreased. However, as ambient pressure is increased from atmosphere to 3.0 bar, spray angle is increased.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.291-294
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• 2002

This study describes the external spray characteristics of deflector nozzle such as the breakup procedures of liquid sheet, spray angle, discharge coefficient and bubble behaviors of spray and SMD at deflector nozzle. In order to visualize the spray behaviors shadow graphy technique were used. According to the increase of injection pressure, development of the spray passes through the dribbling, distoted jet, closed bubble due to the contraction by surface tension forces, the bubble opens into hollow tulip shape, and the curved surface straightened to form a conical sheet like as the simplex swirl atomizer. Spray cone angle was nearly 90 deg. Variations of SMD were examined in order to describe the dependency of SMD on the injection pressure and orifice diameter. The shape of deflector and oriffice diameter had an effect on the discharge coefficient.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.1
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• pp.100-107
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• 1998

Ventilation of the marine engine room is very important for the health of the workers as well as the nomal operation of machines. To find proper ventilation conditions of this engine room, numerical simulation with standard k-.epsilon. model was carried out. In the present study, the marine engine room is considered as a closed space with a heat source and forced ventilation ducts. The injection angle of air supply is found to be important. Injection with downword angle depresses recirculation flow, causing a strong steam in the wider space of the room. Ventilation and removal of the released heat are promoted with this pattern. There is a possibility of local extreme heating at the upper surface of engine when supply and exhaust ports of air are in bilateral symmetry. The effect of the increase of exhaust port area on ventilation decreases as the number of supply port increases.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.198-210
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• 1998

A crank angle-based engine control system has been developed for use as an engine research tool to provide precise control of the fuel injection(timing and duration) and ignition(timing and dwell) in real-time. The engine event information is provided by the engine shaft encoder, and the engine control system uses this information to generate spark and injector control signals for relevant cylinders. Eight different engine types and four different rotary encoder resolutions can be accommodated by this system. Also this system allows a user to individually control the ignition and fuel injection for each cylinder in a simple manner such as through a keyboard or in a real-time operation from a closed-loop control program.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.563-564
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• 2008