Effect of hydrogen enrichment on the flame propagation, emissions formation and energy balance of the natural gas spark ignition engine

Petrol engines can run on natural gas, with little modification. The combustion characteristics of naturalgas is different from that of petrol, which eventually affects the engine performance. The performance of atypical automotive engine was studied running on natural gas, firstly at a constant speed for various loadsand then at a constant load for a range of speeds and results were compared with performance using petrol.Variation of the spark advance, consisting of centrifugal and vacuum advance mechanisms, wasinvestigated. Results showed some reduction in power and slight fall of efficiency and higher exhausttemperature, for natural gas. The air-fuel ratio for optimum performance was higher for gas than for petrol.This variation in spark requirement is mainly due to the slower speed of flame propagation for natural gas.For both the cases, the best power spark advance for natural gas was found to have higher values thanpetrol. This issue needs to be addressed during retrofitting petrol engines for running on natural gas.Journal of Chemical Engineering Vol.ChE 24 2006 42-49

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Study on the extension of lean operation limit through hydrogen enrichment in a natural gas spark-ignition engine

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2007.12.040 ◽

2008 ◽

Vol 33 (4) ◽

pp. 1416-1424 ◽

Cited By ~ 104

Author(s):

Fanhua Ma ◽

Yu Wang

Keyword(s):

Natural Gas ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Hydrogen Enrichment

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Energy Balance of a Spark Ignition Engine Running on Hydrogen, Synthesis Gas and Natural Gas

10.4271/2014-01-1337 ◽

2014 ◽

Cited By ~ 7

Author(s):

Pedro Orbaiz ◽

Michael Brear

Keyword(s):

Energy Balance ◽

Natural Gas ◽

Synthesis Gas ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Hydrogen Synthesis

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An experimental study the impact of the hydrogen enrichment on cycle-to-cycle variations of the large bore and lean burn natural gas spark-ignition engine

Fuel ◽

10.1016/j.fuel.2020.118868 ◽

2020 ◽

Vol 282 ◽

pp. 118868 ◽

Cited By ~ 2

Author(s):

Xiongbo Duan ◽

Banglin Deng ◽

Yiqun Liu ◽

Shunzhang Zou ◽

Jingping Liu ◽

...

Keyword(s):

Experimental Study ◽

Natural Gas ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Lean Burn ◽

Hydrogen Enrichment ◽

The Impact

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Optical analysis of flame inception and propagation in a lean-burn natural-gas spark-ignition engine with a bowl-in-piston geometry

International Journal of Engine Research ◽

10.1177/1468087418822852 ◽

2019 ◽

Vol 21 (9) ◽

pp. 1584-1596 ◽

Cited By ~ 8

Author(s):

Jinlong Liu ◽

Cosmin Emil Dumitrescu

Keyword(s):

Natural Gas ◽

Flame Propagation ◽

Diesel Engines ◽

Pressure Rise ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Expansion Velocity ◽

Cylinder Pressure ◽

Lean Burn ◽

Piston Bowl

Heavy-duty diesel engines can convert to lean-burn natural-gas spark-ignition operation through the addition of a gas injector in the intake manifold and of a spark plug in place of the diesel injector to initiate and control combustion. However, the combustion phenomena in such converted engines usually consist of two distinct stages: a fast-burning stage inside the piston bowl followed by a slow-burning stage inside the squish area. This study used flame luminosity data and in-cylinder pressure measurements to analyze flame propagation inside a bowl-in-piston geometry. The experimental results showed a low coefficient of variation and standard deviation of peak cylinder pressure, moderate rate of pressure rise, and no knocking for the lean-burn (equivalence ratio 0.66), low-speed (900 r/min), and medium-load (6.6 bar IMEP) operating condition. Flame inception had a strong effect on the flame expansion velocity, which increased fast once the flame kernel established, but it reduced near the bowl edge and the entrance of the narrow squish region. However, the burn inside the bowl was very fast. In addition, the long duration of burn inside the squish indicated a much lower flame propagation speed for the outside-the-bowl combustion, which contributed to a long decreasing tail in the apparent heat release rate. Furthermore, cycles with fast flame inception and fast burn inside the bowl had a similar end of combustion with cycles with delayed flame inception and then a retarded burn inside the bowl, which indicated that the combustion inside the squish region determined the combustion duration. Overall, the results suggested that the spark event, the flame development inside the piston bowl, and the start of the second combustion stage affected the phasing and duration of the two combustion stages, which (subsequently) can affect engine efficiency and emissions of diesel engines converted to a lean-burn natural-gas spark-ignition operation.

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An Experimental Investigation of Early Flame Development in an Optical Spark Ignition Engine Fueled With Natural Gas

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4039616 ◽

2018 ◽

Vol 140 (8) ◽

Cited By ~ 26

Author(s):

Cosmin E. Dumitrescu ◽

Vishnu Padmanaban ◽

Jinlong Liu

Keyword(s):

Natural Gas ◽

Flame Propagation ◽

Combustion Engine ◽

Turbulent Flame ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Piston Bowl ◽

Pressure Trace ◽

Flame Development ◽

Flame Region

Improved internal combustion engine simulations of natural gas (NG) combustion under conventional and advanced combustion strategies have the potential to increase the use of NG in the transportation sector in the U.S. This study focused on the physics of turbulent flame propagation. The experiments were performed in a single-cylinder heavy-duty compression-ignition (CI) optical engine with a bowl-in piston that was converted to spark ignition (SI) NG operation. The size and growth rate of the early flame from the start of combustion (SOC) until the flame filled the camera field-of-view were correlated to combustion parameters determined from in-cylinder pressure data, under low-speed, lean-mixture, and medium-load conditions. Individual cycles showed evidence of turbulent flame wrinkling, but the cycle-averaged flame edge propagated almost circular in the two-dimensional (2D) images recorded from below. More, the flame-speed data suggested different flame propagation inside a bowl-in piston geometry compared to a typical SI engine chamber. For example, while the flame front propagated very fast inside the piston bowl, the corresponding mass fraction burn was small, which suggested a thick flame region. In addition, combustion images showed flame activity after the end of combustion (EOC) inferred from the pressure trace. All these findings support the need for further investigations of flame propagation under conditions representative of CI engine geometries, such as those in this study.

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Laminar flame speed correlations for methane, ethane, propane and their mixtures, and natural gas and gasoline for spark-ignition engine simulations

International Journal of Engine Research ◽

10.1177/1468087417720018 ◽

2017 ◽

Vol 18 (9) ◽

pp. 951-970 ◽

Cited By ~ 31

Author(s):

Riccardo Amirante ◽

Elia Distaso ◽

Paolo Tamburrano ◽

Rolf D Reitz

Keyword(s):

Natural Gas ◽

Laminar Flame ◽

Spark Ignition ◽

Flame Speed ◽

Operating Conditions ◽

Spark Ignition Engine ◽

Computational Time ◽

Laminar Flame Speed ◽

Spark Ignition Engines ◽

Empirical Correlations

The laminar flame speed plays an important role in spark-ignition engines, as well as in many other combustion applications, such as in designing burners and predicting explosions. For this reason, it has been object of extensive research. Analytical correlations that allow it to be calculated have been developed and are used in engine simulations. They are usually preferred to detailed chemical kinetic models for saving computational time. Therefore, an accurate as possible formulation for such expressions is needed for successful simulations. However, many previous empirical correlations have been based on a limited set of experimental measurements, which have been often carried out over a limited range of operating conditions. Thus, it can result in low accuracy and usability. In this study, measurements of laminar flame speeds obtained by several workers are collected, compared and critically analyzed with the aim to develop more accurate empirical correlations for laminar flame speeds as a function of equivalence ratio and unburned mixture temperature and pressure over a wide range of operating conditions, namely [Formula: see text], [Formula: see text] and [Formula: see text]. The purpose is to provide simple and workable expressions for modeling the laminar flame speed of practical fuels used in spark-ignition engines. Pure compounds, such as methane and propane and binary mixtures of methane/ethane and methane/propane, as well as more complex fuels including natural gas and gasoline, are considered. A comparison with available empirical correlations in the literature is also provided.

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