• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.387-394
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• 2017

This paper develops a pump system for patient with chronic pain or cancer. The pump module is consists of two micro-valve and membrane. The micro-valve is operated by a solenoid. With two solenoid valves which are connected via a drug transport line, the inlet and outlet are completely blocked. A silicon rubber membrane located between the two valves makes the flow-rate constant without any backflow. This pump module can control the flow-rate of drugs by controlling the time that the valves are opened and closed. The reservoir consists of a drug chamber and a gas chamber. As the gas chamber encloses the drug chamber, propellant gas which is injected into the gas chamber pressurizes the drug chamber regardless of volume of the drug chamber. To design the pump module, analysis a constant efficiency test, and accuracy test for the pump module were conducted.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.7
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• pp.1398-1407
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• 1992

The prediction of heat loss during laminar flame propagation was carried out by measurement of gas pressure and visualization of flame propagation in the constant volume combustion chamber. And to validate the prediction, the instantaneous temperature at wall of combustion chamber was also measured. Consequently, it was found that heat loss was increased according to increasing of maximum flame travel distance, but rate of heat loss for heat release during laminar flame propagation was nearly constant. And heat loss depends on heat transfer area which was contacted the wall by burned gas regardless to spark plug location.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.122-134
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• 1995

The present study was investigated combustion characteristics of methane-air mixtures at stratified charge in a constant volume combustion chamber. The main results obtained from this study can be summarized as follows. In case of ${\phi}_s=1.0$, total burning times greatly affected rather than initial time of pressure increase and maximum combustion pressure. In case of ${\phi}_t=1.0$, initial time of pressure increase and total burning times were affected considerably in comparison with the case of ${\phi}_s=1.0$. Also, even the very lean mixture which total equivalence ratio is ${\phi}_t=0.69$(${\phi}_s=1.0$, ${\phi}_m=0.65$), by changing configuration of the critical passage-hole and using a stratified mixture, it is possible to decrease substantially the initial time of pressure increase. total burning times and NOx concentration without deteriorating combustion characteristics such as maximum combustion pressure, rate of heat release etc. in comparison with the use of single chamber(in case of ${\phi}=1.0$) only. Specifically, our trends were revealed remarkably in the case of Type D which is reduced a flame contact area of sub-chamber side of the passage-hole.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.629-634
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• 2010

Natural gas is a promising alternative fuel that can be used to satisfy the strict engine emission regulations in many countries. To develop natural-gas engines, low emission, efficient fuel consumption, and increased power ratings have to be realized. In this study, a cylindrical constant-volume combustion chamber (CVCC) was used to investigate natural-gas combustion characteristics for different prechamber design parameters and equivalence ratios. In particular, the maximum combustion pressure and mass fraction of the burned gas were evaluated by considering orifice diameter, volume ratio of prechamber and equivalence ratio. Using this result and by analyzing the changes in combustion characteristics with variations in design parameters, the optimum prechamber parameters were determined.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.152-157
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• 2008

The biodiesel becomes one of the favorite alternative fuel applied to diesel engines. This research aims to understand the physics of spray and combustion characteristics of a biodiesel fuel in a constant volume chamber. For spray visualization, biodiesel was injected into a combustion chamber and a high speed camera was applied at various combustion conditions. To investigate heat-release rates and flame propagations, spark was ignited on a hydrogen fuel for the premixed combustion and then biodiesel was injected directly. In addition, parametric study was made by various geometries of combustion chambers and temperatures of fuels and injection pressures. This technology may contribute to improve the performance of bio-diesel engine and reduce emissions in future.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.4
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• pp.31-38
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• 1992

The objective of this study is to determine the ignition feasibility of a single shot, air-assisted gasoline fuel injector operated in a constant volume combustion chamber under atmospheric condition. A number of parameters has been selected for this experiments, such as dwelling time, spark gap position(r,z), spark electrode geometry, supplied air and fuel masses and spray cone deflector angle. On-site visual inspection of the instantaneous flame glow was chosen as one way to judge the successful ignition. In addition, chamber pressure and occasional photography were mobilized as for data recording. It was clearly observed that there was an entrainment air-fuel mixture toward spray axis from the spray formation and its development later on. The optimum ignition conditions were found for those parameters given above.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.75-83
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• 2001

This paper presents the evaluation of combustion characteristics of sing-hole plasma jet ignitions in comparison with conventional spark ignition for variable of swirl velocity. Plasma jet plugs are three types according to ejecting directions : center of chamber, positive and negative swirl flow direction. Experiments are carried out for equivalent ratio 1.0 of LPG-air mixture in a constant volume cylindrical vessel. Not only the flame propagation is photographed at intervals, but the pressure variation in the combustion chamber is also recorded throughout the entire combustion process. The results show that the plasma jet ignitions and spark ignition enhance the overall combustion rate by increasing the swirl velocity. The dependence of the combustion rate swirl velocity leade to the conclusion that the placma jet plug, which ejects plasma jet to the cwnter of combustion chamber is the most desirable ignitor than other plugs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.125-134
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• 2015

This is the third paper on the combustion characteristics of the landfill gas in a constant volume combustion chamber for a large displacement volume commercial engine. It is the first in this series to discuss the effects of the torch device on combustion. The results show that an optimum orifice ratio exists regardless of the torch volume, and a few adverse effects on the combustion are observed for an excessively small orifice ratio. In addition, the torch ignition decreases the initial burn duration, and the decrease in the heat transfer caused by this decreased duration contributes to an increase in the peak combustion pressure. Finally, the torch mostly plays a positive role in shortening the main burn duration when the combustion condition is worsened by a lower methane fraction. Yet, the torch decreases the initial burn duration rather than the main burn as the methane fraction increases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.345-350
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• 2017

Downsizing is widely applied to diesel engines in order to improve fuel efficiency and reduce exhaust emissions. Engine sizes are becoming smaller but pressure and temperature inside combustion chambers are increasing. Therefore, research for fuel spray under high pressure and temperature conditions is important. A constant volume chamber which simulates high temperature and pressure likely to be found in diesel engines was developed in this study. Pressure and temperature were increased abruptly because of ignition of the pre-mixture in the constant volume chamber. Then pressure and temperature were gradually decreased due to the heat loss through the chamber wall. Fuel spray occurred when temperature and pressure were reached at the target condition. In this experiment, the temperature condition should be exactly defined to understand the relation between fuel evaporation and ambient temperature. A fast response thermocouple was developed and used to measure the temporal and spatial temperature distribution during the combustion process inside the combustion chamber. In the results, the core temperature was slightly higher than the bulk temperature calculated by the gas equation. Ed-note: do you want to say 'ideal gas equation'? This was attributed to the heat transfer loss through the chamber wall. The vertical temperature deviation was higher than the horizontal temperature deviation by 5% which resulted from the buoyancy effect.

• International Journal of Automotive Technology
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• v.8 no.1
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• pp.19-25
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• 2007

This experimental study was carried out to obtain both low emissions and high thermal efficiency by rapid bulk combustion. Two kinds of experiments were conducted to obtain fundamental data on the operation of a RI engine by a radical ignition method. First, the basic experiments were conducted to confirm rapid bulk combustion by using a radical ignition method in a constant volume chamber (CVC). In this experiment, the combustion velocity was much higher than that of a conventional method. Next, to investigate the desirable condition of engine operation using radical ignition, an applied experiment was conducted in an actual engine based on the basic experiment results obtained from CVC condition. A sub-chamber-type diesel engine was reconstructed using a SPI type engine with controlled injection duration and spark timing, and finally, converted to a RI engine. In this study, the operation characteristics of the RI engine were examined according to the sub-chamber's specifications such as the sub-chamber volume and the diameter and number of passage holes. These experimental results showed that the RI engine operated successfully and was affected by the ratio of the passage hole area to the sub-chamber volume.