• Title, Summary, Keyword: Backfire

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Extension of Backfire Limited Equivalence Ratio in Hydrogen Engine by Using Multi Point Ignition Method (다점점화에 의한 수소기관의 역화발생 억제효과에 관한 검토)

  • Kim, Y.Y.;Lee, C.W.;Lee, Jongtai
    • Transactions of the Korean hydrogen and new energy society
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    • v.14 no.2
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    • pp.131-137
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    • 2003
  • Backfire occurrence must be controlled for the practical use of hydrogen fueled engine. It was found from preceeding studies that crevice volume around piston rings could effect a backfire occurrence. In this study, a possible countermeasure to backfire occurrence was evaluated by using multi point ignition method around piston ring. The results showed that backfire limited equivalence ratio was increased by a little due to a enhancing effect of mixture combustion around piston crevice volume.

A Study of Backfire Control in a Hydrogen-Fueled Engine with External Mixture Using Changes of Valve Overlap Period (밸브오버랩기간 변화에 의한 흡기관 분사식 수소기관의 역화억제에 관한 연구)

  • Kang, J.K.;Cong, Huynh Thanh;Noh, K.C.;Lee, J.T.
    • Proceedings of the KSME Conference
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    • pp.3311-3316
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    • 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.

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A Study on the Damage by Engine Backfire in the Mixer-type LPG Vehicles (Mixer-type LPG차량에서 엔진역화에 의한 차량 파손에 관한 연구)

  • Jeon, Kwang-Su;Choi, Sung-Eun;Chin, Young-Wook;Chung, Jin-Eun
    • Proceedings of the Safety Management and Science Conference
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    • pp.223-229
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    • 2009
  • The engine backfire leading to the damage to the intake system is observed in the mixer-type LPG engines. The hot spot flowing back into the intake manifold from the engine cylinder during the valve overlap period is known to give rise to the backfire. This backfire is known to be the main cause of the abrupt stop of the vehicle leading to the accidents on the streets. In this study, the cylinder pressure buildup at the later stage of combustion due to the prolonged burning is presumed to be the main cause of the backflow leading to the backfire. This is experimentally observed by creating the engine misfire using the ill-conditioned ignition systems.

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An Experimental Study on Phenomenon of Backfire in H2 HCCI Engine (예혼합 압축착화 수소기관의 역화현상에 관한 실험적 연구)

  • Lee, Jongmin;Lee, Jonggoo;Lee, Kwangju;Lee, Jongtai
    • Transactions of the Korean hydrogen and new energy society
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    • v.26 no.1
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    • pp.28-34
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    • 2015
  • HCCI (Homogeneous Charged Compression Ignition) hydrogen engine has relatively narrower operation range caused by backfire occurrence due to the rapid pressure rising by using higher compression ratio and significant reaction velocity. In this study, to grasp of backfire process and characteristic in the HCCI research hydrogen engine, in-cylinder pressure, intake pressure and backfire limit range are analyzed with compression ratio and intake valve open timing, experimentally. As the result, it is observed that knock is occurred just before backfire occurrence in HCCI hydrogen engine but not spark igntion type, this phenomenon is always the same for the above variables. Also backfire limit range are expanded up to 50% for the more retarding intake valve open timing in this operating conditions.

The Characteristics of Backfire for 2 stroke Free-Piston Hydrogen Fueled Engine with Uni-flow Scavenging (Uni-flow 소기방식 2행정 프리피스톤 수소기관의 스트로크변화에 따른 역화 특성)

  • Cho, Kwan-Yeon;Cho, Hyung-Wook;Lee, Jong-Tae
    • Transactions of the Korean hydrogen and new energy society
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    • v.20 no.5
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    • pp.371-377
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    • 2009
  • Backfire characteristics for hydrogen fueled free piston engine with uni-flow scavenging is investigated with different stroke, exhaust vlave openning timing and fuel-air equivalence ratio by using RICEM (Rapid Intake Compression Expansion Machine) for combustion research of free piston engine. As results, it is found that backfire can be occurred due to slow combustion of unhomogeneous mixture in the piston crevice volume or/and in the cylinder near piston head. And the more stroke of free piston H2 engine with uni-flow scavenging is short the more opening timing of exhaust valve have to be advanced to control backfire.

Study on Backfire for a Two-Stroke Hydrogen Fueled Free-Piston Engine with Loop Scavenging (루프소기방식을 갖는 2행정 프리피스톤 수소기관의 역화에 관한 연구)

  • Cho, Kwan-Yeon;Byun, Chang-Hee;Back, Dae-Ha;Lee, Jong-Tae
    • Transactions of the Korean hydrogen and new energy society
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    • v.21 no.6
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    • pp.487-492
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    • 2010
  • For developing a two-stroke free-piston hydrogen engine with high efficiency and low emission, determination of the scavenging type is one of the most important factor. In this research, backfire characteristics for loop scavenging were analyzed with the number of piston crevice volume and piston expansion speed. Rapid Compression Expansion Machine, RCEM was used for combustion research of the free piston $H_2$ engine in the experiment. As the results, it was shown that although backfire occurring in a loop scavenging type can be partially controled by a complete exhaust of burned gas, possibility of backfire basically exist due to the structure which piston crevice volumes contact with fresh mixture in a scavenging port. However, a loop scavenging may be considered as combustion chamber of a free piston $H_2$ engine from the point of view that backfire does not occur nearby lean equivalence ratio obtained high thermal efficiency. It was also analyzed that an advances of backfire occurrence timing with increase of the fuel-air equivalence ratio were due to promotion of flame propagation into piston crevice volumes by decrease of the quenching distance.

The Characteristics of Backfire for a Free-Piston Hydrogen Fueled Engine with Reverse Uni-flow Scavenging (Reverse uni-flow 소기방식을 갖는 2행정 프리피스톤 수소기관의 역화 현상에 관한 연구)

  • Byun, Chang-Hee;Choi, Kwan-Yeon;Back, Dae-Ha;Lee, Jong-Tae
    • Transactions of the Korean hydrogen and new energy society
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    • v.21 no.2
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    • pp.98-103
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    • 2010
  • In order to develop two-stroke free-piston hydrogen engine to obtain high thermal efficiency and low emission, backfire occurrence have to be prevented. In this research, backfire characteristics are analyzed as functions of the intake valve opening timing and compression chamber pressure under piston by using RICEM (Rapid Intake Compression Expansion Machine) that has reverse uni-flow scavenging. As the result, reverse uni-flow scavenging is advantage about back fire. but, it exists suitable intake valve opening timing and its timing become known that equivalence ratio 1 retard until the piston rises. Also, To rise chamber pressure of lower piston, this does not cause backfire occurs in equivalent ratio 0.6 observed back fire. Therefore, 2cycle hydrogen fueled free-piston engine is undesirable scavenging compression by compressing the piston.

Backfire Occurrence by Abnormal Electric Discharge in Hydrogen Fueled Engine (수소기관의 이상점화에 의한 역화발생)

  • Kim, Y.Y.;Ryu, T.H.;Lee, Jong T.
    • Transactions of the Korean hydrogen and new energy society
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    • v.13 no.1
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    • pp.65-73
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    • 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.

A Study on the Backfire and Abnormal Combustion in the Free-piston Hydrogen Fueled Engine (프리피스톤 수소기관의 역화 및 이상연소에 관한 연구)

  • Kim, K.M.;Park, S.W.;Lee, J.H.;Noh, K.C.;Lee, J.T.;Lee, Y.K.
    • Transactions of the Korean hydrogen and new energy society
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    • v.17 no.1
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    • pp.1-7
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    • 2006
  • The free-piston hydrogen fueled engine is estimated as the next generation power system which can obtain high efficiency and low emission, simultaneously. In order to develop the free-piston hydrogen fueled engine, it is necessary to stable the combustion. The engine combustion, backfire and knock phenomenons were studied by using RICEM for researching combustion characteristics of free-piston engine. As the results, backfire occurrence was not observed in the free-piston engine under limited experimental condition. And knocking occurred in case of higher cylinder wall temperature.

A Study on Enhancement of Combustion Performance by Dilution of Hydrogen in Heavy-Duty Hydrogen Engine (수소기관의 수소연료의 희석에 의한 역화억제효과에 관한 연구)

  • KIM, S.Y.;KIM, Y.Y.;Kim, Y.T.;LEE, JONG T.
    • Transactions of the Korean hydrogen and new energy society
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    • v.15 no.4
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    • pp.348-354
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    • 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.