Biofuels for Spark Ignition Engines: Comparison
View Latest Version
Please note this is a comparison between Version 2 by Peter Tang and Version 1 by Ashraf Elfasakhany.

Biofuels are receiving increased scientific attention, and recently different biofuels have been proposed for spark ignition engines. Different biofuels, mainly ethanol, methanol, i-butanol-n-butanol, and acetone, are blended together in single dual issues and evaluated as renewables for SIE. Each blend showed some advantaged and drawbacks in terms of emissions and performance. 

  • biofuels
  • single blends
  • dual blends
  • spark ignition engines (SIE)

1. Introduction

The world is on the edge of an energy crisis, due to limited energy sources along with ever-increasing energy demand [1]. Statistics show that energy needs will increase by about 50% in 2025. Currently, the available sources of energy mainly depend on fossil fuel, which is limited with a non-renewable capability. The main sources of energy are oil (32%), coal (27%), and natural gas (22%) [2]. The problems of environmental pollution and global warming, related to fossil fuels, as well as the oscillation of oil prices can significantly support searching for alternative fuels for the future. Among the most promising alternatives, biofuels are recommended [3]. Biofuels are fuels produced from bio-origin sources, such as biomass.

Biofuels were used in the early decades of the last century but due to the low price of fossil fuels, biofuels were limited in entering into commercial play. Historically, at the beginning of the Second World War, biofuels, especially alcohols, were reused as fuel sources. Later on, in the beginning of the seventies of the last century, an oil crisis was revealed where the gulf countries refrained from exporting oil [2]. This led to a steep rise in the crude oil price, whereby the price of a barrel increased from USD 3 to USD 45. This, in turn, led to the world being directed towards biofuels again [4]. Currently, several countries are using biofuels; in particular, the largest biofuel-producing countries are the United States of America, Brazil, China, and India, respectively, due to their benefits, as discussed later [5].

Despite the benefits of biofuels as a renewable source of energy, especially the reductions in greenhouse gases emissions and global warming, in comparison with fossil fuels, biofuels represent less than 1% of the global market for automobile fuels, and such biofuels depend strongly on governmental support [6,7][6][7]. Many countries have started to take serious steps toward producing and using biofuels as a main source of energy in their different energy applications, in order to meet the jump in their energy needs and reduce their imported energy dependency. In particular, Brazil is one of the leading countries in the production of biofuels, where 30% of the biofuels are used in its transport trucks [8]. The United States, for example, plans to replace 30% of liquid oil with biofuels in 2025 [6]. India increased biofuel rates from 5% to 20% [9]. India plans to reduce its dependency on oil by 10% in 2022 [10]. The European Union (EU) countries increased their dependency on biofuels [11]. Biofuel production doubled from 2003 to 2017 in some EU countries. The biggest producers of ethanol in the EU are Germany, France, and Poland. The greatest biofuel consumers in the EU are considered in Latvia (31.2%), Finland (26.7%) and Sweden (24.8%) [12]. China aims to increase its biofuel production capacity from 76 Mt in 2015 to 152 Mt in 2030 [13].

Biofuels are currently among the most important sources of renewable fuels, unlike other natural sources such as petroleum, coal, and other fossil fuels. Biofuels could be derived from plants and animal wastes (mostly horse and cow manures). The agricultural residues are also used for biofuels production. In detail, there are several sources of biofuels from agricultural residues, such as coconut and palm oils [14,15][14][15]. There are also available sources such as sunflower seeds, soybeans, peanuts, cones, wheat, sugar beet and maize [16,17][16][17]. In general, biofuels can be produced from dedicated crops, also called energy crops, or from wastes produced by agro-industry and agriculture, or from food waste or food by-product wastes. Biofuels are generated by a series of biological processes, such as hydrolysis, fermentation, and microbiological enzymes, which convert sugar molecules into fuels. Using such methods, hydrocarbons are extracted from the biomass sources; as such, biofuels are classified as natural organic compounds.

In comparison with fossil fuels, biofuels offer several benefits, as discussed next. Biofuel is a renewable source of energy; it turns the agriculture residues into energy; it makes an efficient use of residues with additional income instead of useless disposal; it helps towards a cleaner environment by turning residues into fuel instead of farmers burning them; and finally, it is an available source of energy in all countries, thus meeting strategy needs [18].

One of the main benefits of biofuels as promising future fuels includes their being carbon-free. Carbon dioxide, which is emitted from biofuels in combustion conditions, is extracted from the atmosphere while plants grow. This means that there is no emission of carbon dioxide in biofuel combustion. Biofuels also include oxygen in their structure, which makes fuel burn more completely, e.g., reduces the fuel pollutant emissions produced from volatile organic compounds [19,20][19][20]. Biofuels also have a high octane number, which eliminates the need to add lead to increase the octane number of regular fuels, as in the fossil fuel condition [21]. In addition, biofuels are degraded biologically, and are mostly non-toxic fuels [22].

Despite the several benefits of biofuels, as discussed above, there are some drawbacks. One of problems of biofuels is their production from food agriculture sources, such as maize and wheat; this, in turn, leads to an increase in food prices, and that can directly affect the lives of poor people [23,24][23][24]. Recently, this problem has been partially solved by imposing domestic legislation to prevent the production of biofuels from food sources, using agricultural and animal residues instead [25,26][25][26]. One further problem is the increased costs of biofuel production; however, this problem gets better with time, and in the near future the price would be competitive with other fuels.

Biofuels are reviewed in the literature, and some studies have focused on biofuel types [27]. McDowall et al. [28] reviewed the future of biofuels. Global production methods of biofuels in recent utilizations were reviewed by Refs. [29,30,31][29][30][31]. Recent technologies for biofuel productions from different residues were reviewed by Ref. [32]. Biofuel production systems from the modeling point of view were reviewed by Ref. [33]. The future of biofuel as renewable energy sources is reviewed by Refs. [34,35,36][34][35][36]. In spite of all such review studies, there is still a gap in the reviewing of biofuels [37]. There are few studies focusing on the review of biofuels for Spark ignition engines (SIE) [13].

2. Biofuels for Spark Ignition Engines

Spark ignition engines (SIE) generally work based on the principle of receiving a mixture of air and gasoline fuel, compressing it, and igniting it using a spark-plug to produce a high temperature/pressure in the cylinder(s). At the time of the invention of the SIE (at the beginning of the last century), biofuels (from feed energy corps and food) were used as an energy source in the engine [38]. The first use of biofuels (ethanol) was in the 1800s. Later on, in 1826, the scientist Sawmill Morey worked to improve the engine’s performance using biofuels/bioethanol [38]. In 1860, the German engineer Nicholas Otto used biofuels (alcohols) in one of his engines [38]. In 1908, Henry Ford designed an engine using biofuels (ethyl alcohol) as an energy source [38]. In 1917, the famous scientist Alexander Graham Bell presented a paper in National Geographic about biofuels (ethanol) [38]. However, due to the low cost of fossil fuels, the using of biofuels was limited. Currently, researchers are directed toward biofuel blend technique. The first time gasoline was mixed with biofuels was in 1930 [38]. Biofuels were in development for the first time as fuels for transportation via a fermentation process of sugars into ethanol [39]. Several countries marketed biofuel blends for use in the SIE, such as Germany, Brazil, the Netherlands, France, United States of America and many other countries [40,41,42][40][41][42].

Biofuels are generally classified into four generations, according to early studies [43,44,45,46,47,48,49][43][44][45][46][47][48][49]. In the first generation, the biofuels were generated from food energy corps. This led to increased food prices due to food shortages [50] and, accordingly, the world moved into the next generation. In the second generation, the biofuels were from non-food corps, such as wheat, straw, and corn husk. The technology of biofuel production is scarce and complex, which makes biofuel production expensive and, in turn, the third generation was introduced. In the third generation, the biofuels were manufactured from microbial algae and cyanobacteria. In the fourth generation, the biofuels are generated from genetic microorganisms using thermochemical processing of CO2. However, the fourth generation is still under development. In the following is a detailed discussion of using different biofuel blends in spark ignition engines.

The investigation on ethanol and methanol fuels showed many advantages in terms of engine efficiency, released emissions and high thermal proportion, which led to development of widespread use of such fuel [59,84]. Up to 10 percent n-butanol and iso-butanol in gasoline was investigated by Elfasakhany [98,127]; emissions and mixed fuel efficiency are improved for mixed fuels compared to clean gasoline. Elfasakhany [139] examined SIE pollutant emissions and engine efficiency. Compared to clean gasoline, the findings showed better engine efficiency and lower pollutant emissions for fuel blends. In literature, Elfasakhany [148-154], examined performance and pollutant emissions of SIE using ethanol, methanol, n-butanol, i-butanol, and acetone, at same blend rates (3, 7, and 10 vol.%) and engine working conditions. The comparison focused on the engine emissions via CO

The investigation on ethanol and methanol fuels showed many advantages in terms of engine efficiency, released emissions and high thermal proportion, which led to development of widespread use of such fuel [51][52]. Up to 10 percent n-butanol and iso-butanol in gasoline was investigated by Elfasakhany [53][54]; emissions and mixed fuel efficiency are improved for mixed fuels compared to clean gasoline. Elfasakhany [55] examined SIE pollutant emissions and engine efficiency. Compared to clean gasoline, the findings showed better engine efficiency and lower pollutant emissions for fuel blends. In literature, Elfasakhany [56][57][58][59][60][61][62], examined performance and pollutant emissions of SIE using ethanol, methanol, n-butanol, i-butanol, and acetone, at same blend rates (3, 7, and 10 vol.%) and engine working conditions. The comparison focused on the engine emissions via CO

2, CO, and UHC and performance via volumetric efficiency, brake power, and torque in a wide range of engine speeds from 2600 to 3400 r/min. Additionally, Elfasakhany [158,159] compared between different blends under same conditions. Results recommended some blends (especially ternary ones) than the dual types.

, CO, and UHC and performance via volumetric efficiency, brake power, and torque in a wide range of engine speeds from 2600 to 3400 r/min. Additionally, Elfasakhany [63][64] compared between different blends under same conditions. Results recommended some blends (especially ternary ones) than the dual types.

3. Benefits and Weaknesses of Using Biofuels in SIE

Biofuels show many benefits, such as decreasing greenhouse gases (GHG) and global warming, and shortening the dependency on fossil fuels. In the literature, some studies have discussed the advantages of specific biofuels in terms of combustion and emissions. In particular, Ryojiro Minato [160][65] discussed the advantages of bio-ethanol; Liu et al. [161][66] discussed the advantages of bio-methanol; Veza et al. [162][67] discussed the advantages of butanol. In other studies, researchers discussed the disadvantages of biofuels [163][68]. One study summarized the advantages and disadvantages of different biofuel types. The benefits and weaknesses of using biofuels in SIE either in single or dual blended conditions with gasoline are summarized by Elfasakhany [164][69]. The study concluded that the biofuels can offer promising well-to-wheel CO2 balance in our environment, and increase engine efficiency and output power. Biofuels’ oxygen content also offers benefits for the fuel combustion. Nevertheless, biofuels showed some weaknesses, such as minor carbon and hydrogen contents and heating values, and some corrosiveness of engine systems for some biofuel type(s). Boiling temperature, absorption with water, vapor toxicity and autoignition of biofuels showed benefits for some types and weaknesses for others; a summary of the benefits and weaknesses of using biofuels in cars is given in Table 1.

Table 1. Benefits and weaknesses of using biofuels compared to gasoline in SI engines.

Properties

Bio-Ethanol

Bio-Methanol

I-Butanol

N-Butanol

Acetone

Performance

Ben.

Ben.

Ben.

Ben.

Ben.

Emissions

Ben.

Ben.

Ben.

Ben.

Ben.

Oxygen content

Ben.

Ben.

Ben.

Ben.

Ben.

Hydrogen content

Wek.

Wek.

Wek.

Wek.

Wek.

Carbon content

Wek.

Wek.

Wek.

Wek.

Wek.

Absorption with water

Wek.

Wek.

Ben.

Ben.

Ben.

Boiling Temp.

Wek.

Wek.

Ben.

Ben.

Wek.

Vapor toxicity

Ben.

Ben.

Wek.

Wek.

Ben.

Heating value

Wek.

Wek.

Wek.

Wek.

Wek.

Autoignition

Ben.

Ben.

Wek.

Wek.

Ben.

Corrosion

Wek.

Wek.

Ben.

Ben.

Wek.

Ben: benefits, Wek: weaknesses.

4. Summary

Different biofuels are compared with each other and with the commercial gasoline under same rates and conditions. Ethanol and methanol showed many benefits and some drawbacks as alternative fuels for spark ignition engines, in comparison with gasoline in spark ignition engines. They can improve have the capability to improve engine performance and pollutant emissions; however, but they showed some perform problems in terms of engine starting condition in cold environment as well as a and vapor lock in hot climate condition. They showed also incompatibility with some engine material and their miscible with water is another disadvantage.

Different biofuels are compared with each other and with the commercial gasoline under same rates and conditions. Ethanol and methanol showed many benefits and some drawbacks as alternative fuels for spark ignition engines, in comparison with gasoline. They have the capability to improve engine performance and pollutant emissions; however, they showed some problems in terms of engine starting condition in cold environment as well as a vapor lock in hot climate condition. They showed also incompatibility with some engine material and their miscible with water is another disadvantage.

References

  1. Midttun, A.; Piccini, P.B. Facing the climate and digital challenge: European energy industry from boom to crisis and transformation. Energy Policy 2017, 108, 330–343.
  2. Celik, A.N.; Ozgür, E. Review of Turkey’s photovoltaic energy status: Legal structure, existing installed power and comparative analysis. Renew. Sustain. Energy Rev. 2020, 134, 110344.
  3. Elfasakhany, A.; Bai, X.S. Numerical and experimental studies of irregular-shape biomass particle motions in turbulent flows. Eng. Sci. Technol. 2019, 22, 249–265.
  4. Alpanda, S.; Alva, A.P. Oil crisis, energy-saving technological change and the stock market crash of 1973–74. Rev. Econ. Dyn. 2010, 13, 824–842.
  5. Ajanovic, A.; Haas, R. On the future prospects and limits of biofuels in Brazil, the US and EU. Appl. Energy 2014, 135, 730–737.
  6. Thompson, W.; Whistance, J.; Meyer, S. Effects of US biofuel policies on US and world petroleum product markets with consequences for greenhouse gas emissions. Energy Policy 2011, 39, 5509–5518.
  7. Kay, A.; Ackrill, R. Governing the transition to a biofuels economy in the US and EU: Accommodating value conflicts, implementing uncertainty. Policy Soc. 2012, 31, 295–306.
  8. Martinez, C.L.M.; Saari, J.; Melo, Y.; Cardoso, M.; Almeida, G.M.; Vakkilainen, E. Evaluation of thermochemical routes for the valorization of solid coffee residues to produce biofuels: A Brazilian case. Renew. Sustain. Energy Rev. 2021, 137.
  9. Usmani, R.A. Potential for energy and biofuel from biomass in India. Renew. Energy 2020, 155, 921–930.
  10. Sindelar, S.; Aradhey, A. India Biofuels Annual 2017. In USDA Foreign Agriculture Service; New Delhi, India, 2017. Available online: (accessed on 25 November 2020).
  11. Buchspies, B.; Kaltschmitt, M.; Neuling, U. Potential changes in GHG emissions arising from the introduction of biorefineries combining biofuel and electrofuel production within the European Union–A location specific assessment. Renew. Sustain. Energy Rev. 2020, 134, 0395.
  12. Bórawski, P.; Borawska, A.B.; Szymanska, E.J.; Jankowski, K.J.; Dubis, B.; Dunn, J.W. Development of renewable energy sources market and biofuels in The European Union. J. Clean. Prod. 2019, 228, 467–484.
  13. Hao, H.; Liu, Z.; Zhao, F.; Ren, J.; Chang, S.; Rong, K.; Du, J. Biofuel for vehicle use in China: Current status, future potential and policy implications. Renew. Sustain. Energy Rev. 2018, 82, 645–653.
  14. Ge, J.C.; Kim, H.Y.; Yoon, S.K.; Choi, N.J. Optimization of palm oil biodiesel blends and engine operating parameters to improve performance and PM morphology in a common rail direct injection diesel engine. Fuel 2020, 260, 6326.
  15. Ge, J.C.; Kim, H.Y.; Yoon, S.K.; Choi, N.J. Reducing volatile organic compound emissions from diesel engines using canola oil biodiesel fuel and blends. Fuel 2018, 218, 266–274.
  16. Elfasakhany, A. Powder biomass fast pyrolysis as in combustion conditions: Numerical prediction and validation. Renew. Energy Focus 2018, 27, 78–87.
  17. Elfasakhany, A. Modeling of Pulverised Wood Flames. Ph.D. Thesis, Fluid Mechanics Department, Lund University, Lund, Sweden, 2005.
  18. Elfasakhany, A.; Bai, X.S. Modeling of Pulverised Wood Combustion: A Comparison of Different Models. Prog. Comp. Fluid Dyn. 2006, 6, 188–199.
  19. Elfasakhany, A.; Klason, T.; Bai, X.S. Modeling of Pulverised Wood Combustion Using a Functional Group Model. Combust. Theory Modeling 2008, 12, 883–904.
  20. Elfasakhany, A. Modeling of Secondary Reactions of Tar (SRT) Using a Functional Group Model. Int. J. Mech. Eng. Tech. 2012, 3, 123–136.
  21. Sangeeta; Moka, S.; Pande, M.; Rani, M.; Gakhar, R.; Sharma, M.; Rani, J.; Bhaskarwar, A.N. Alternative fuels: An overview of current trends and scope for future. Renew. Sustain. Energy Rev. 2014, 32, 697–712.
  22. Thangavelu, S.K.; Ahmedb, A.S.; Ani, F.N. Review on bioethanol as alternative fuel for spark ignition engines. Renew. Sustain. Energy Rev. 2016, 56, 820–835.
  23. Elfasakhany, A. Alcohols as Fuels in Spark Ignition Engines: Second Blended Generation; Lambert Academic Publishing: Bahnhofstrabe, Germany, 2017; ISBN 978–3–659–97691–9.
  24. Elfasakhany, A. Benefits and Drawbacks on the Use Biofuels in Spark Ignition Engines; Lambert Academic Publishing: Beau Bassin, Mauritius, 2017; ISBN 978–620–2–05720–2.
  25. Elfasakhany, A.; Tao, L.X.; Bai, X.S. Transport of pulverized wood particles in turbulent flow: Numerical and experimental studies. Energy Procedia 2014, 61, 1540–1543.
  26. Elfasakhany, A.; Tao, L.; Espenas, B.; Larfeldt, J.; Bai, X.S. Pulverised Wood Combustion in a Vertical Furnace: Experimental and Computational Analyses. Appl. Energy 2013, 112, 454–464.
  27. Lin, C.Y.; Lu, C. Development perspectives of promising lignocellulose feedstocks for production of advanced generation biofuels: A review. Renew. Sustain. Energy Rev. 2021, 136, 0445.
  28. McDowall, W.; Eames, M. Forecasts, scenarios, visions, backcasts and roadmaps to the hydrogen economy: A review of the hydrogen futures literature. Energy Pol. 2006, 34, 1236–1250.
  29. Mahmudul, H.M.; Hagos, F.Y.; Mamat, R.; Adam, A.A.; Ishak, W.F.W.; Alenezi, R. Production, characterization and performance of biodiesel as an alternative fuel in diesel engines–a review. Renew. Sustain. Energy Rev. 2017, 72, 497–509.
  30. Balat, M.; Balat, H. Recent trends in global production and utilization of bio-ethanol fuel. Appl. Energy 2009, 86, 2273–2282.
  31. Bezerra, T.L.; Ragauskas, A.J. A review of sugarcane bagasse for second-generation bioethanol and biopower production. Biofuel. Bioprod. Biorefin. 2016, 10, 634–647.
  32. Gupta, A.; Verma, J.P. Sustainable bio-ethanol production from agro-residues: A review. Renew. Sustain. Energy Rev. 2015, 41, 550–567.
  33. Hall, L.M.H.; Buckley, A.R. A review of energy systems models in the UK: Prevalent usage and categorisation. Appl. Energy 2016, 169, 607–628.
  34. Mofijur, M.; Masjuki, H.H.; Kalam, M.; Rahman, S.A.; Mahmudul, H. Energy scenario and biofuel policies and targets in ASEAN countries. Renew. Sustain. Energy Rev. 2015, 46, 51–61.
  35. Azad, A.K.; Rasul, M.; Khan, M.M.K.; Sharma, S.C.; Hazrat, M. Prospect of biofuels as an alternative transport fuel in Australia. Renew. Sustain. Energy Rev. 2015, 43, 331–351.
  36. Cremonez, P.A.; Feroldi, M.; Araújo, A.V.; Borges, M.N.; Meier, T.W.; Feiden, A.; Teleken, J.G. Biofuels in Brazilian aviation: Current scenario and prospects. Renew. Sustain. Energy Rev. 2015, 43, 1063–1072.
  37. Alizadeh, R.; Peter, D.; Soltanisehat, L.L. Outlook on biofuels in future studies: A systematic literature review. Renew. Sustain. Energy Rev. 2020, 134, 0326.
  38. Singh, R.S.; Walia, A. Biofuels Historical Perspectives and Public Opinions; CRC Press; Taylor and Francis Group: Boca Raton, FL, USA, 2016; ISBN 9781315370743.
  39. Bergthorson, J.M.; Thomson, M.J. A review of the combustion and emissions properties of advanced transportation biofuels and their impact on existing and future engines. Renew. Sustain. Energy Rev. 2015, 42, 1393–1417.
  40. Nadaleti, W.C.; Przybyla, G.; Filho, P.B. Analysis of emissions and combustion of typical biofuels generated in the agroindustry sector of Rio Grande do Sul State–Brazil: Bio75, syngas and blends. J. Clean. Prod. 2019, 208, 988–998.
  41. Santos, I.T. Confronting governance challenges of the resource nexus through reflexivity: A cross-case comparison of biofuels policies in Germany and Brazil. Energy Res. Soc. Sci. 2020, 65, 1464.
  42. Puricelli, S.; Cardellini, G.; Grosso, M. A review on biofuels for light-duty vehicles in Europe. Renew. Sustain. Energy Rev. 2021, 137, 0398.
  43. Liew, W.H.; Hassim, M.H.; Ng, D.K.S. Review of evolution, technology and sustainability assessments of biofuel production. J Clean. Prod. 2014, 71, 11–29.
  44. Carneiro, M.L.N.M.; Pradelle, F.; Braga, S.L.; Gomes, M.S.P.; Martins, A.R.F.A.; Turkovic, F. Potential of biofuels from algae: Comparison with fossil fuels, ethanol and biodiesel in Europe and Brazil through life cycle assessment (LCA). Renew. Sustain. Energy Rev. 2017, 73, 632–653.
  45. Alalwan, H.A.; Alminshid, A.H.; Aljaafari, H.A.S. Promising evolution of biofuel generations. Subject review. Renew. Energy Focus 2019, 28, 127–139.
  46. Oehlschlaeger, M.A.; Wang, H.; Sexton, M.N. Prospects for biofuels: A review. J. Therm. Sci. Eng. Appl. 2013, 5, 1006.
  47. Souza, L.L.P.; Lora, E.E.S.; Palacio, J.C.E.; Rocha, M.H.; Renó, M.L.G.; Venturini, O.J. Comparative environmental life cycle assessment of conventional vehicles with different fuel options, plug-in hybrid and electric vehicles for a sustainable transportation system in Brazil. J. Clean. Prod. 2018, 203, 444–468.
  48. Bhargavi, G.; Rao, N.P.; Renganathan, S. Review on the extraction methods of crude oil from all generation biofuels in last few decades. In IOP Conference Series: Materials Science and Engineering, Proceedings of the International Conference on Recent Advances in Materials, Mechanical and Civil Engineering, Hyderabad, India, 1–2 June 2017; IOP Publishing Ltd.: Bristol, UK, 2018; Volume 330.
  49. Awudu, I.; Zhang, J. Uncertainties and sustainability concepts in biofuel supply chain management: A review. Renew. Sustain. Energy Rev. 2012, 16, 1359–1368.
  50. Menten, F.; Chèze, B.; Patouillard, L.; Bouvart, F. A review of LCA greenhouse gas emissions results for advanced biofuels: The use of meta-regression analysis. Renew. Sustain. Energy Rev. 2013, 26, 108–134.
  51. Elfasakhany, A. The effects of ethanol–gasoline blends on performance and exhaust emission characteristics of spark ignition engines. Int. J. Automot. Eng. 2014, 4, 608–620.
  52. Elfasakhany, A. Investigation on performance and emissions characteristics of an internal combustion engine fuelled with petroleum gasoline and a hybrid methanol–gasoline fuel. Int. J Eng. Tech. 2013, 13, 24–43.
  53. Elfasakhany, A. Experimental study on emissions and performance of an internal combustion engine fueled with gasoline and gasoline/n-butanol blends. Energy Convers. Manag. 2014, 88, 277–283.
  54. Elfasakhany, A. Experimental investigation on SI engine using gasoline and a hybrid iso-butanol/gasoline fuel. Energy Convers Manag. 2015, 95, 398–405.
  55. Elfasakhany, A. Performance and emissions analysis on using acetone–gasoline fuel blends in spark–ignition engine. Eng. Sci. Tech. JESTECH 2016, 19, 1224–1232.
  56. Elfasakhany, A. Investigations on performance and pollutant emissions of spark–ignition engines fueled with n-butanol–, iso-butanol–, ethanol–, methanol–, and acetone–gasoline blends: A comparative study. Renew. Sustain. Energy Rev. 2017, 71, 404–413.
  57. Elfasakhany, A. Gasoline engine fueled with bioethanol-bio-acetone-gasoline blends: Performance and emissions exploration. Fuel 2020, 274, 7825.
  58. Elfasakhany, A. Dual and Ternary Biofuel Blends for Desalination Process: Emissions and Heat Recovered Assessment. Energies 2021, 14, 61.
  59. Elfasakhany, A. Performance and emissions of spark–ignition engine using ethanol–methanol–gasoline, n-butanol–iso-butanol–gasoline and iso-butanol–ethanol–gasoline blends: A comparative study. Eng. Sci. Tech. JESTECH 2016, 19, 2053–2059.
  60. Elfasakhany, A. Exhaust emissions and performance of ternary iso-butanol–bio-methanol–gasoline and n-butanol–bio-ethanol–gasoline fuel blends in spark-ignition engines: Assessment and comparison. Energy 2018, 158, 830–844.
  61. Elfasakhany, A. Investigations on the effects of ethanol–methanol–gasoline blends in a spark–ignition engine: Performance and emissions analysis. Eng. Sci. Tech. JESTECH 2015, 18, 713–719.
  62. Elfasakhany, A.; Mahrous, A.F. Performance and emissions assessment of n-butanol–methanol–gasoline blends as a fuel in spark–ignition engines. Alex. Eng. J. 2016, 55, 3015–3024.
  63. Elfasakhany, A. Experimental study of dual n-butanol and iso-butanol additives on spark–ignition engine performance and emissions. Fuel 2016, 163, 166–174.
  64. Elfasakhany, A. Engine performance evaluation and pollutant emissions analysis using ternary bio-ethanol–iso-butanol–gasoline blends in gasoline engines. J. Clean. Prod. 2016, 139, 1057–1067.
  65. Veza, I.; Said, M.F.M.; Latiff, Z.A. Recent advances in butanol production by acetone-butanol-ethanol (ABE) fermentation. Biomass Bioenergy 2021, 144, 5919.
  66. Wang, Y.; Hu, L.L.L.; Zhuang, L.; Lu, J.; Xu, B. A feasibility analysis for alkaline membrane direct methanol fuel cell: Thermodynamic disadvantages versus kinetic advantages. Electrochem. Commun. 2003, 5, 662–666.
  67. Elfasakhany, A. Biofuels in Automobiles: Advantages and Disadvantages: A Review. Curr. Altern. Energy 2019, 3, 1–7.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Video Production Service
Feedback