• Proceedings of the KSME Conference
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• 2001.11b
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• pp.806-811
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• 2001

Since the characteristics of combustion and pollutant in Diesel engines were mainly effected by the characteristics of in-cylinder gas flow and fuel spray, an understanding of those was essential to the design of the D.I. Diesel engines. The improvement of volumetric efficiency of air charging into combustion chamber is a primary requirement to obtain better mean effective pressure of an engine. Since parameters such as the air resistances in intake and exhaust flow passages, valve lift and valve shape influence greatly to the volumetric efficiency, it is very important to investigate the flow characteristics of intake and exhaust port which develops air motion in the combustion chamber. In this study, two approach methods were used for design intake and exhaust port; experiment and computation which were made by using steady flow test rig and commercial CFD code. This paper presents the results of an experimental and analytical investigation of steady flow through the prototype cylinder head ports and valves of the HHI's H21/32 HIMSEN Engine.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.44-51
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• 2005

According to the increasing concern on the global environment, the $CO_2$ regulation has been discussed including automobile emission regulation. In order to cope with this rapid changing circumstances, the development of an ultra low emission and super fuel economy automobile is essential. Direct injection LPG engine is the one of the possible future engine to maximize the engine efficiency. This experimental study for the development of direct injection LPG engine technology is promoted with two parts; spray characteristics of high pressure swirl injector, and performance characteristics of direct injection LPG engine. Engine characteristics according to the fuel was analyzed in order to establish stratified combustion technology for LPG engine by using the DISI engine. In the engine experiment, control system was manufactured for gasoline and LPG fuel. The engine was modified 2,000 cc GDI engine (fuel supply device, fuel injection device). Through this experiment, engine operating condition, engine speed and spark timing (MBT), fuel injection position, and fuel rate were investigated.

• International Journal of Naval Architecture and Ocean Engineering
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• v.3 no.4
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• pp.286-292
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• 2011

In order to design a shear coaxial injector of solid particles for underwater propulsion system, basic experiments on gas-liquid shear coaxial injector are necessary. In the gas-liquid coaxial injector self-pulsation usually occurs with an intense scream. When self-pulsation occurs, mass flow rate oscillation and intense scream are detected by the interactions between the liquid and gas phase. Self-pulsation must be suppressed since this oscillation may cause combustion instabilities. Considerable research has been conducted on self-pulsation characteristics, but these researches are conducted in swirl coaxial injector. The main objective of this research is to understand the characteristics of self-pulsation in shear coaxial injector and reveal the mechanism of the phenomenon. Toward this object, self-pulsation frequency and spray patterns are measured by laser diagnostics and indirect photography. The self-pulsation characteristics of shear coaxial injector are studied with various injection conditions, such as the pressure drop of liquid and gas phase, and recess ratio. It was found that the frequency of the self-pulsation is proportional to the liquid and gas Reynolds number, and proportional to the L/d.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.26-33
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• 2006

The use of high-density propellants can provide performance advantages in space launch vehicles by allowing an improved structural ratio due to smaller propellants tanks. The Jet A-1 fuel is currently used in Korean space launch vehicle development and it has lower density than other advanced hydrocarbon fuels such as RP-1 or RG-1. In this paper, the results of hydraulic and combustion tests conducted for the two newly developed densified hydrocarbon fuels are presented and they are compared with the results of Jet A-1. Conclusively, the two densified hydrocarbon fuels presented equivalent or even higher combustion performance compared to the Jet A-1 and the performance difference was found to be more obvious in the injector of external mixing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.3
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• pp.275-283
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• 2013

An injector that uses methane gas ($CH_4$) and liquid oxygen ($LO_x$) as propellants was designed to verify the combustion characteristics of an engine that uses methane, which is one of the next-generation propellants. A swirl/shear coaxial-type injector was used, and flow analysis was performed using Fluent to determine the main design parameters of the injector. A hydraulic test was performed to understand the atomization and spray pattern characteristics of the injector. Next, a combustion test was performed at the design point to understand the ignition and combustion stability. Additional combustion tests were performed according to the O/F ratio to investigate the combustion characteristics and stabilities using the characteristic exhaust velocity ($C^*$) and fluctuation of the chamber pressure. The experimental results showed that the combustion efficiency was greater than 90%, and the pressure fluctuation was lower than 2% under all conditions.