• Transactions of the Korean hydrogen and new energy society
• /
• v.4 no.1
• /
• pp.1-9
• /
• 1993

To find performance and knock limit for compression ratio in hydrogen fueled engine, the variable compression ratio hydrogen fueled engine which was able to vary compression ratio during firing was manufactured and estimated. The characteristics of the variable compression ratio hydrogen fueled engine were as follows : 1) compression ratio variation by moving of cylinder head, 2) OHC which can be realized low S/V ratio, short flame propagation distance and unvariable configuration of combustion chamber for compression ratio variation, 3) direct injection of hydrogen gas to restrict back fire.

• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.879-885
• /
• 2000

This study is carried out to make clear the reason of occurrence of sudden acceleration incident of AT vehicle. The stepping motor is used to control the engine speed at idle by compensating the volume of air. By the way it's valve is contaminated by blow-by gas, deposit and back fire etc. This contamination could occur the load of motor at low temperature. This plays an important role in damaging the motor's coil with the motor's performance interfered. If it's coil is damaged the ISC could malfunction. If these phenomena occur, the speed of engine may increase or the engine may stall with hunting.

• Journal of Advanced Marine Engineering and Technology
• /
• v.27 no.1
• /
• pp.117-123
• /
• 2003

In a bi-fuel engine using gasoline and LPG fuel, with the current ignition timing for gasoline being used, the effective performance could not be taken in LPG fuel supply mode. The ignition timing in LPG fuel mode must be advanced much more than that of gasoline mode for the compensation of its lower flame speed, due to engine torque drop. This study aims to develop the control system for ignition spark timing conversion which is composed of hardwares and control algorithm for gasoline/LPG engine. We propose the control system which can advance the ignition spark timing in LPG fuel mode more than used in gasoline fuel mode. The advance of ignition timing is achieved by change of the ignition dwell time of coil igniter. The engine torque and F/E(Fuel-Economy) in LPG fuel mode are measured to evaluate the difference of engine performance between before and alter changing ignition spark timings. The engine torque and F/E are increased respectively, which proves the developed control system is effective so much for gasoline and LPG bi-fuel engine.

• Transactions of the Korean hydrogen and new energy society
• /
• v.15 no.4
• /
• pp.348-354
• /
• 2004

Hydrogen gas has several merits such as lower ignition energy, wide flammability and shorter quenching distance. It leads to high thermal efficiency but backfire occurrence. In this study, feasibility of expansion of BFL(Back-Fire Limit) equivalence ratio and combustion characteristics by a dilution of hydrogen fuel are experimently examined by using experimental heavy duty single cylinder hydrogen fueled engine. As results, it is found that BFL equivalence ratio is expanded to rich range and torque is increased.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.7
• /
• pp.1702-1708
• /
• 1995

Owing to the serious problem of hydrocarbon fuel such as environmental pollution, the development of alternative fuel is very urgent. To adopt hydrogen to the internal combustion engine, a solenoid-drive type in-cylinder injection system was constructed. The injection system was installed to the single cylinder research engine, and the engine performance and the emission of citric oxide were tested upon the fuel-air equivalence ratio and the spark timing. In the case of in-cylinder injection system, hydrogen is injected after the intake valve is close, so it is possible to operate the engine without the back fire and the fall of its volumetric efficiency. In the region of the fuel-air equivalence ratio below 0.5, hydrogen and air aren't well mixed and the thermal efficiency is lowered, so the nozzle should be designed to inject hydrogen uniformly into the combustion chamber. In the region of the fuel-air equivalence ratio above 0.7,the fuel-air mixture burns very fast and the amount of citric oxide emission increases rapidly, so the spark timing should be retarded as compared with MBT.

• Transactions of the Korean hydrogen and new energy society
• /
• v.13 no.1
• /
• pp.65-73
• /
• 2002

Because of low flame ion density in hydrogen-air mixture, many residual electric energy could be existed in the ignition system of hydrogen engine, If these residual energy discharged abnormally during intake stroke, it may be the cause of backfire occurrence which is serious problem in development of hydrogen fueled engine but unsolved in spite of many concerned research on it. In this study, the possibility of backfire occurrence by abnormal electric discharge and countermeasure of that were investigated by using the experimental single cylinder hydrogen fueled engine with two types of ignition system. The results show that abnormal electric discharge appeared in low load with low ion density and then results in back fire occurrence, It is also seen that countermeasure method installing larger earth resistance in high tension code is effective to control abnormal electric discharge.

• Fire Science and Engineering
• /
• v.24 no.3
• /
• pp.1-8
• /
• 2010

This study is searched in the on actual condition and analysis about the fire fighting measure of 123 main wooden cultural properties designated by the Cultural Heritage Administration. First, the management of wooden cultural properties and the present condition of fire occurrence are arranged. Second, The field research and the information research of related government agencies are done from August. 2008 to October. 2008 about 123 main wooden cultural properties: Cultural properties designation classification, location classification, building area, number of possession cultural properties, present condition of fire fighting, a fire engine drive direction for fire suppression, number of self-defense fire brigade, fire administrator nomination, and the distance and time from a fire station are arranged in this study. Third, the inside and outside present conditions are classified and analyzed by average index for the fire occurrence risk of 123 main wooden cultural properties. And the basic data is arranged for the fire fighting measure of main wooden cultural properties.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.3311-3316
• /
• 2007

To analyze the influence of valve overlap period on a backfire occurrence, the single cylinder research engine with MCVVT(Mechanical Continuous Variable Valve Timing) system is developed and backfire limit equivalence ratio defined as fuel-air ratio equivalence ratio at which backfire occurs is examined according to various valve overlap period. The MCVVT is the system to control valve overlap period by mechanical device. It is estimated that the lower valve overlap period has the higher backfire limit equivalence ratio though the same energy is supplied. When the valve overlap period is changed from 30$^{circ}$ CA to 0$^{circ}$ CA, backfire limit equivalence ratio is increased 74%, approximately. It means that valve overlap period is concern in backfire occurrence, and may be one of the methods for controlling back fire occurred in a $H_2$ engine.

• Transactions of the Korean hydrogen and new energy society
• /
• v.33 no.3
• /
• pp.255-260
• /
• 2022

Hydrogen gas fuel was applied to a small-sized two stroke engine for a mobile power source instead of gasoline fuel. Port fuel supply showed a limitation in terms of power due to the back fire at the engine intake manifold. So in this study, hydrogen direct injection system was applied to overcome this drawback by using a low pressure direct gas injector. The result from this strategy showed that hydrogen direct injection improved fuel efficiency as well as torque and power comparing to the port fuel supply system.

• Fire Science and Engineering
• /
• v.23 no.3
• /
• pp.121-130
• /
• 2009

This study is researched about the field trip of temples and the data for fire extinguishment manual of fire stations: it is done from June 2008 to December 2008 the 80 main temple wooden cultural properties among the 124 main wooden cultural properties appointed by the Cultural Heritage Administration. Cultural properties appointment classification, location classification, temple area, building area in a temple, building area of appointment cultural properties, a fire engine drive direction for fire suppression in a fire, distance from a fire station, and present condition of a fire administrator are researched. The cultural properties possess characteristic is in 2 cases: the whole things in a temple are appointed as cultural properties and only the wooden building is. The cultural properties are classified: the transport is possible or not. The special quality of cultural properties are classified for early correspondence and cultural properties transport in a fire and the basic data are arranged for damage limitation.