• 한국자동차공학회논문집
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• 제6권4호
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• pp.47-55
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• 1998

A new ignition system concept was developed to improve ignition performance, accuracy of control and the reliability of the ignition system. The new ignition system has ho호 frequency discharge characteristics with 1.5-2.0 ms discharge duration, in place of the usual solitary longer duration event. We applied the system to a commercial engine to study its influence on the maximum combustion pressure attained during the cycle, when this peak pressure occurred, imep, variation rate of the engine speed and the flammability limit of a lean mixture. In this study, we clarified that the new ignition system had a beneficial effect of the lean mixture flammability limit. Also for a given mixture strength we found that the mew ignition system gave a higher peak cylinder pressure than in the case of the conventional ignition system.

• 한국안전학회지
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• 제19권1호
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• pp.66-71
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• 2004

This paper describes that the improved effects on the ignition limit are studied by parallel safety components for propane-air 5.25vol.% mixture gas in low voltage inductive circuits. The experimental devices are used in the IEC type spark ignition test apparatus. The improved effects on the ignition limit are respectively obtained as the maximum rising rate of 650%, 1,080% by composing parallel circuits between inductance and safety components (condenser and diode) as compared with disconnecting inductance with the safety components. The more values of inductance the higher improved effects of ignition limit rise. This improving method for the ignition limit is not concerned with the safety components. Diode appears to effect greatly better than condenser. It is considered that the result can be used for not only data for researches and development of intrinsically safe explosion-proof machines which are applied equipment and detectors used in hazardous areas but also for data for its equipment tests.

• 한국화재소방학회논문지
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• 제18권1호
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• pp.18-23
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• 2004

본 논문은 IEC형 불꽃점화 시험장치를 이용하여 저압 유도회로의 최소 점화한계를 프로판-공기 5.25 Vol.%의 혼합 가스에 대하여 실험적으로 구하였으며, 또한 유도회로의 인덕턴스 L에 안전소자로서 저항을 병렬접속 하였을 경우 프로판-공기 5.25 Vol.%의 혼합 가스에 대한 점화한계 개선효과를 고찰하였다. 그 결과, 최소 점화한계는 전류의 크기에 따라 좌우되었다. 또한, 전원으로부터 공급되는 에너지는 인덕턴스에 우선 축적되고, 그 초과분의 에너지가 폭발성 가스의 점화원으로 작용하였다. 점화한계 개선효과는 인덕턴스가 300mH일 때, 최고 330%의 개선효과가 나타났으며 인덕턴스가 클수록 점화한계 개선효과가 크게 나타났다. 또한 병렬로 접속한 저항의 크기가 적을수록 점화한계 개선 효과가 크다. 본 연구결과는 본질안전 방폭형 전기기기의 연구개발을 위한 기본자료로 활용할 수 있을 뿐만 아니라 이들 기기의 방폭 성능에 대한 시험자료로도 활용이 가능할 것으로 사료된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1854-1856
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• 1996

This study describes the minimum ignition limit for LPG-Ai-r mixtures by switching sparks in radio-frequency limits using RF power supply and IEC type ignition spark apparatus. As a result, the minimum ignition limit voltage is increased in proportional to the rate of increasing of frequency in LPG-Air mixed gas. Especially, increment between 10[kHz] and 30[kHz] is typical. It is considered that ignition is caused by one discharge until 10 [kHz] and, beyond 10[kHz] ignition is caused by more than two discharges. The reason is analysed that energy loss is caused by existing pause interval between discharges.

• 한국자동차공학회논문집
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• 제5권6호
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• pp.183-191
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• 1997

For the improvement of ignitability we need ignition energy and its discharge characteristics which are suitable for a part distribution of the mixture density around the ignition spark plug and the flow characteristics of the mixture in the combustion. Especially, for the solving of the instability of initial ignition and lean ignitability limit in the case of lean-burn combustion, the more powerful ignition energy is required. The conclusions from the observation can be summarized as follows: 1) The ignitability limit for HIS expands wider and the combustion is more stable than for CDI. 2) The combustion duration and ignition timing depend upon the distribution of local mixture density in the vicinity of ignition spark plug.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.92-98
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• 2003

An LPG engine for heavy-duty vehicles has been developed using liquid phase LPG injection (hereafter LPLi) system which has regarded as one of the next generation LPG fuel supply systems. In this wort to investigate the lean bum characteristics of heavy-duty LPLi engine, various injection timing (SOI, start of injection) and double ignition method were tested. The results showed that lean misfire limit of LPLi engine could be extended. by 0.2 $\lambda$ value, using the optimal SOI timing in LPLi system. Double ignition method test was carried out by installing the second spark plug and modified ignition circuit to ignite two spark plugs simultaneously. Double ignition resulted in the stable combustion under ultra lean bum condition, below $\lambda=1.7$, and extension of lean misfire limit compare to ordinary case. Therefore, LPLi engine with optimal SOI and double ignition method could be normally operated at around $\lambda=1.9$ and showed higher engine performance.

• 한국연소학회지
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• 제22권2호
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• pp.36-41
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• 2017

Aero gas turbine engines must demonstrate their ability to be ignited on ground conditions or relighted in flight. The electric spark ignition is usually used in current aero gas turbine engines. Experiments on ignition characteristics relating to spark igniter penetration depth under atmospheric pressure and temperature conditions were conducted on the model combustor which is scaled in 1/18. Exciter was operated during 2 seconds, and successful ignition phenomena were confirmed by the pressure rising sharply in combustor. In addition, instantaneous ignition images were captured by a high-speed camera. It showed kernel propagation and successful ignition events in the sector model combustor. Ignition test results showed that ignition limit with increase in penetration depth of the igniter plug was wider. When the penetration depth of the igniter plug increased under the same fuel injection pressure condition, successful ignition events were obtained in higher differential pressure conditions between inlet and outlet of the combustor. The results demonstrate that the ratio of the combustible mixture, which is exposed to the high temperature environment around the igniter plug tip, increases. Thereby affect the combustor ignition performance.

• 에너지공학
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• 제23권3호
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• pp.1-6
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• 2014

The more or less homogeneous fuel-air mixture that exists at the end of the compression process is ignited by an electric ignition spark from a spark plug shortly before top dead center. The actual moment of ignition is an optimization parameter; it is adapted to the engine operation so that an optimum combustion process is obtained. Brake mean effective pressure (BMEP) of the spark ignition energy control device (IECD) than conventional spark system at the stoichiometric mixture is increased about 9%. For lean burn engine, the lean limit is extended about 25% by using the IECD. It was considered the stability of combustion by the increase of flame kernel according to the high ignition energy supplies in initial period and discharge energy period lengthen by using the IECD.

• 오토저널
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• 제10권4호
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• pp.66-74
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• 1988

The ignition quality of ignition system is influenced by spark energy, discharge pattern of spark energy and spark duration. In this paper, the characteristics of multiple spark ignition system have been investigated for various number of spark and spark interval. The results, which were compared with those obtained with a standard single spark ignition, show that engine output is increased, and lean misfire limit is extended with the multiple spark ignition system. The most effective number of spark at the most effective spark interval that are determined by engine performance test, were 6 times spark at 0.02ms spark interval. For the above condition of spark, engine torque was increased about 20% comparing with conventional ignition system and lean misfire limit was extended to air-fuel ratio 22.5:1. This study researched the rate of heat release and quantity of heat release influenced by a condition of spark on the mass burned in order to investigate the relationship between the rate of mass burned and number of spark times.

• 한국가스학회지
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• 제1권1호
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• pp.106-112
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• 1997

본 연구는 직류 저항회로의 개폐불꽃에 의한 폭발성 가스의 점화한계를 실험적으로 고찰하였다. 실험은 IEC형 불꽃점화 시험장치의 폭발용기에 폭발성 가스(메탄-공기 프로판-공기, 에틸렌-공기, 수소-공기)를 각각 넣고 텅스텐 전극과 카드뮴 전극사이에서 발생하는 3,200회의 개폐불꽃에 의한 점화유무를 확인하므로서 점화한계를 구하였다. 또한 실험장치의 점화감도교정을 실험한 후에 실시하므로서 실험의 정확성을 기하였다. 실험결과 최소 점화 전류값을 갖는 최소점화한계농도는 메탄-공기 8.3 [$Vol\%$], 프로판-공기 5.25[$Vol\%$], 에틸렌-공기 7.8[$Vol\%$], 수소-공기 21[$Vol\%$]로서 기존의 실험결과와 유사한 결과를 나타내었다. 또한 최소점화한계농도에서 전압과 최소점화잔류와의 관계를 구한 결과 최소점화한계는 메탄, 프로판, 에틸렌, 수소가스의 순서로 낮아졌고 점화전류의 크기는 전원전압의 크기와 반비례하고, 전극의 과열현상으로 인하여 전압 약 20(V)이하에서는 최소점화전류가 2(A)를 넘으면서 심화한계곡선이 급격히 상승한다는 것 등을 알 수 있었다.