A Computational Study of Abnormal Combustion Characteristics in Spark Ignition Engines

The U.S. Renewable Fuel Standard requires an increase in the production of ethanol and advanced biofuels up to 36 billion gallons by 2022. Ethanol will be limited to 15 billion gallons, which leaves 21 billion gallons to come from other sources. Due to its high octane number, renewable character, and minimal toxicity, ethanol was believed to be one of the most favorable alternative fuels to displace gasoline in spark ignition engines. Replacing gasoline with ethanol results in a substantial reduction in vehicle range, and high ethanol content blends can cause material compatibility issues and require adaptive engine calibrations. In addition, ethanol is fully miscible in water which requires blending at distribution sites instead of the refinery. Higher carbon number alcohols, on the other hand, have a higher energy density and lower affinity for water than ethanol, which could mitigate some of the above mentioned issues. However, little information is available on the combustion characteristics of a majority of the longer-chain alcohols. This study evaluates the combustion properties of higher carbon number alcohols, ranging from ethanol (C2) to hexanol (C6) in a direct-injection, spark-ignition engine. Test fuels are created by splash blending alcohols at a volumetric concentration of 50% with a blendstock for oxygenate blending. Combustion characteristics are evaluated by comparing overall efficiencies as well as heat release characteristics and emissions for a set of representative steady-state operating points. Results suggest that combustion properties of blends of alcohols with carbon numbers from two to six are similar to those of the reference fuel at low and medium engine loads. Properties of blends of alcohols with carbon numbers from two to four are similar to those of the reference fuel even at high loads. However, due to their reduced knock resistance, the suitability of longer chain alcohols, specifically C5 and longer, as blending agents at increased levels is questionable.

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Performances and Emissions Characteristics of Three Main Types Composition of Gasoline-Ethanol Blended in Spark Ignition Engines

International Review of Mechanical Engineering (IREME) ◽

10.15866/ireme.v10i7.9968 ◽

2016 ◽

Vol 10 (7) ◽

pp. 552

Author(s):

Marthen E. N. Paloboran ◽

I. Nyoman Sutantra ◽

Bambang Sudarmanta

Keyword(s):

Spark Ignition ◽

Spark Ignition Engines

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Methods of testing small spark ignition engines for agricultural use

10.3403/00060303u ◽

2015 ◽

Keyword(s):

Spark Ignition ◽

Spark Ignition Engines ◽

Agricultural Use

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Ethanol/Gasoline Blends as Alternative Fuel in Last Generation Spark-Ignition Engines: A Review on CO and HC Engine Out Emissions

Energies ◽

10.3390/en14134034 ◽

2021 ◽

Vol 14 (13) ◽

pp. 4034

Author(s):

Paolo Iodice ◽

Massimo Cardone

Keyword(s):

Physicochemical Properties ◽

Alternative Fuels ◽

Experimental Studies ◽

Alternative Fuel ◽

Exhaust Emissions ◽

Spark Ignition ◽

Operating Conditions ◽

Spark Ignition Engine ◽

Spark Ignition Engines ◽

The Impact

Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to investigate the effect on engine out emissions and combustion efficiency. In the next section, this article focuses on the impact of ethanol/gasoline fuels on CO and HC formation. Many studies related to combustion characteristics and exhaust emissions in spark-ignition engines fueled with ethanol/gasoline fuels are thus discussed in detail. Most of these experimental investigations conclude that the addition of ethanol with gasoline fuel mixtures can really decrease the CO and HC exhaust emissions of last generation spark-ignition engines in several operating conditions.

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State of Art of Using Biofuels in Spark Ignition Engines

Energies ◽

10.3390/en14030779 ◽

2021 ◽

Vol 14 (3) ◽

pp. 779

Author(s):

Ashraf Elfasakhany

Keyword(s):

Engine Performance ◽

Spark Ignition ◽

Pollutant Emissions ◽

Spark Ignition Engines ◽

Engine Emissions ◽

Cold Starting ◽

Starting Conditions ◽

Unburned Hydrocarbons ◽

Scientific Attention ◽

State Of Art

Biofuels are receiving increased scientific attention, and recently different biofuels have been proposed for spark ignition engines. This paper presents the state of art of using biofuels in spark ignition engines (SIE). Different biofuels, mainly ethanol, methanol, i-butanol-n-butanol, and acetone, are blended together in single dual issues and evaluated as renewables for SIE. The biofuels were compared with each other as well as with the fossil fuel in SIE. Future biofuels for SIE are highlighted. A proposed method to reduce automobile emissions and reformulate the emissions into new fuels is presented and discussed. The benefits and weaknesses of using biofuels in SIE are summarized. The study established that ethanol has several benefits as a biofuel for SIE; it enhanced engine performance and decreased pollutant emissions significantly; however, ethanol showed some drawbacks, which cause problems in cold starting conditions and, additionally, the engine may suffer from a vapor lock situation. Methanol also showed improvements in engine emissions/performance similarly to ethanol, but it is poisonous biofuel and it has some sort of incompatibility with engine materials/systems; its being miscible with water is another disadvantage. The lowest engine performance was displayed by n-butanol and i-butanol biofuels, and they also showed the greatest amount of unburned hydrocarbons (UHC) and CO emissions, but the lowest greenhouse effect. Ethanol and methanol introduced the highest engine performance, but they also showed the greatest CO2 emissions. Acetone introduced a moderate engine performance and the best/lowest CO and UHC emissions. Single biofuel blends are also compared with dual ones, and the results showed the benefits of the dual ones. The study concluded that the next generation of biofuels is expected to be dual blended biofuels. Different dual biofuel blends are also compared with each other, and the results showed that the ethanol–methanol (EM) biofuel is superior in comparison with n-butanol–i-butanol (niB) and i-butanol–ethanol (iBE).

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