• Journal of the Korean Institute of Gas
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• v.13 no.4
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• pp.46-52
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• 2009

Hydrogen can extend the lean misfire limit to a large extent when it is mixed with conventional fuels for an internal combustion engine. This study is about fuel reforming to produce hydrogen enriched gas as a fuel for engine. Especially gasoline, which consists of numerous hydrocarbon fuels, considered as source of reformed gas. Various hydrocarbons, including commercial fuel were reformed and potentialities of reformed gas on vehicles were accessed. The reforming efficiency and hydrogen yield were observed. Maximum hydrogen yield were found with different gas hourly space velocity(GHSV) and O2/C ratio of reforming conditions.

• Journal of Hydrogen and New Energy
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• v.27 no.4
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• pp.441-446
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• 2016

Alcohols are particularly attractive as alternative fuels because they are a renewable resource. This paper describes the performance and emission characteristics of ethanol and methanol gasoline blended fuels in a spark ignition engine. This experimental results showed that alcohol gasoline blended fuels decreased the torque, brake mean effective pressure, and brake power decreased when alcohol blended fuels were applied to a gasoline engine and also CO, HC and NOx emissions were reduced in accordance with the contents of alcohol contents.

• Journal of Hydrogen and New Energy
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• v.8 no.1
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• pp.23-29
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• 1997

The combustion and smoke emission of an indirect injection diesel engine Were investigated running the engine on Hydrogen/diesel fuels. Hydrogen fuel supplied to the intake pipe was varied 0 to 10 percent of DF2' s heating value. The most inportant finding was that the smoke emission is not decreased with increase of hydrogen fuel supplement. Also, the ignition delay is almost negligible over 10 percent hydrogen fuel mixture.

• Proceedings of the KSME Conference
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• 2007.05b
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.84-91
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• 2006

A heavy duty hydrogen-natural gas fueled engine can obtain stable operation at ultra lean conditions and reduce emissions extremely. Reduction of $CO_2$ in its engine is one of the most benefit. In this study, rate of hydrogen addition($R_{dH2}$) and compression ratio($\varepsilon$) were investigated including performance of this engine. As results, it was found that phenomenon of pressure oscillation when increasing $R_{dH2}$ and $\varepsilon$, it means occurring knock. It consider that pressure oscillation was increased due to fast burning speed of hydrogen. Even if same compression ratio, pressure oscillation was remarkable increased according to increasing $R_{dH2}$. Therefore, limit compression ratio of knock occurring was reduced by increasing $R_{dH2}$.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.530-533
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• 2008

배출가스 및 이산화탄소 등 환경규제 강화와 에너지 고갈 문제는 기존의 내연기관, 동력전달장치, 소재 등의 성능 향상과 함께 대체에너지를 사용하는 자동차의 필요성이 증가하고 있으며, 이에 따라 수소연료전지자동차 등의 상용화가 요구되고 있다. 기존 자동차와는 패러다임이 전혀 다른 수소연료전지자동차는 현재 다양한 방향으로 연구 개발되고 있으므로 수소연료전지자동차 관련 평가기술 중 연료소비율 측정방법도 그에 따라 개발되고 진행되어야 할 것이나 현재 국내에 이와 관련한 체계적인 연구가 미미한 실정이며, 국제적인 표준도 현재 설정되어 있지 않은 상황이다. 따라서 현재까지 진행 중인 수소연료전지자동차 연료소비율 측정방법에 대한 기준 동향 및 연구 사례 조사를 통해 관련 연구 계획의 수립과 향후 수소연료전지자동차 연료소비율에 대한 평가기술 도출을 위한 기초 자료로 활용하기 위하여 본 연구를 수행하였다.

• Journal of Hydrogen and New Energy
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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.

• Journal of Hydrogen and New Energy
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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.

• Journal of the korean Society of Automotive Engineers
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• v.26 no.1
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• pp.49-51
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• 2004

• Journal of Hydrogen and New Energy
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• v.14 no.4
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• pp.283-290
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• 2003

To clarify the cause of backfire occurrence and realize a hydrogen fueled engine linear alternator system, dynamic characteristics of a free-piston hydrogen engine were analyzed and compared with those of conventional reciprocating engines. It was found that the mean velocity and acceleration of a free-piston engine were higher than those of reciprocating engines. Piston displacement and compression ratio were varied with the change of the fuel mass flow rate. Therefore, the operational stability and controllability were the most important thinks of the development of a free-piston hydrogen engine.