Effects of Stroke to Bore Ratio on Exergy Balance in Spark Ignition Engines

Öz

This study aims to investigate theoretically the effects of stroke to bore ratio on exergy balance in spark ignition (SI) engines. For this purpose, a two–zone quasi–dimensional cycle model was developed for SI engines without considering the complex calculation of fluid dynamics. The combustion process is simulated as turbulent flame entrainment model in the cycle simulation. Principles of the second law of thermodynamics were applied to the developed model in order to perform the exergy (or availability) analysis. The variations of exergetic terms and irreversibilities throughout the investigated part of the cycle were analyzed depending on stroke to bore ratio. The results of the study showed that variation of stroke to bore ratio have significant effects on the variation of the exergetic terms, irreversibilities and efficiencies. Exergy transfer with work increases, while exergy transfer with heat decreases with increasing of stroke to bore ratio. The maximum increment in exergy transfer with work is about 12.5% and maximum decrement in exergy transfer with heat is about 11.25% for the stroke to bore ratio of 1.3 compared to stroke to bore ratio of 0.7. Irriversibilities and exergy transfer with exhaust decrease with the increasing of stroke to bore ratio. The maximum decrements are about 3.1% in the irriversibilities and 4.9% in exergy transfer with exhaust for the stroke to bore ratio of 1.3 compared to stroke to bore ratio of 0.7. The first and second law efficiencies are increase, while brake specific fuel consumption decreases with the increase of the stroke to bore ratio. The maximum increments are about 12.3% in the first and second law efficiencies and the maximum decrement is about 11.3% in brake specific fuel consumption for the stroke to bore ratio of 1.3 compared to stroke to bore ratio of 0.7.

Anahtar Kelimeler

• Spark ignition engine
• Stroke to bore ratio
• Exergy analysis

Kaynakça

1. Khoa N. X., Nhu Q. and Lim O., “Estimation of parameters affected in internal exhaust residual gases recirculation and the influence of exhaust residual gas on performance and emission of a spark ignition engine,” Applied Energy, 278, 115699, 2020.
2. Ozcan H. and Yamin J. A. A., “Performance and emission characteristics of LPG powered four stroke SI engine under variable stroke length and compression ratio,” Energy Conversion and Management, 49, 1193–1201, 2008.
3. Poulos S. G. and Heywood J. B., “The effect of chamber shape on spark ignition engine combustion,” Society of Automotive Engineering, SAE paper no 830334, 1–27, 1983.
4. Sung N. W. and Jun S. P., “The effects of combustion chamber geometry in an SI engine”, Society of Automotive Engineering, SAE paper no 972996, 227–239, 1997.
5. Filipi Z. S. and Assanis D. N., “The effect of the stroke–to–bore ratio on combustion, heat transfer and efficiency of a homogeneous charge spark ignition engine of given displacement,” International Journal of Engine Research, 1(2), 191–208, 2000.
6. Sher E. and Bar–Kohany T., “Optimization of variable valve timing for maximizing performance of an unthrottled SI engine–a theoretical study,” Energy, 27, 757–775, 2002.
7. Hu Z., Whitelaw J. H. and Vafidis C., “Flame propagation studies in a four–valve pentroof–chamber spark ignition engine,” Society of Automotive Engineering, SAE paper no 922321, 1–11, 1992.
8. Caton J. A., “Detailed results for nitric oxide emissions as determined from a multiple–zone cycle simulation for a spark–ignition engine,” Fall Technical Conference of the ASME, Internal Combustion Engine Division, New Orleans, Los Angeles, pp. 1–19, 2002.

9. Rakopoulos C. D. and Giakoumis E. G., “Second law analyses applied to internal combustion engines operation,” Progress in Energy and Combustion Science, 32(1), 2–47, 2006.
10. Moran M. J. and Shapiro H. N., “Fundamentals of engineering thermodynamic,” New York: John Wiley & Sons Inc., 2000.
11. Caton J. A., “A review of investigations using the second law of thermodynamics to study internal–combustion engines,” SAE World Congress, Detroit, Michigan, pp. 1–15, 2000.
12. Rakopoulos C. D., “Evaluation of a spark ignition engine cycle using first and second law analysis techniques,” Energy Conversion and Management, 34(12), 1299–1314, 1993.
13. Gallo W. L. R. and Milanez L. F., “Exergetic analysis of ethanol and gasoline fueled engines,” Society of Automotive Engineers, SAE paper no 920809, 907–915, 1992.
14. Shapiro H. N. and Van Gerpen J. H., “Two zone combustion models for second law analysis of internal combustion engines,” Society of Automotive Engineers, SAE paper no 890823, 1408–1422, 1989.
15. Alasfour F. N., “Butanol–a single–cylinder engine study: exergy analysis,” Applied Thermal Engineering, 17(6), 537–549, 1997.
16. Caton J. A., “Results from the second–law of thermodynamics for a spark–ignition engine using a cycle simulation,” Fall Technical Conference of the ASME, Internal Combustion Engine Division, Ann Arbor, Michigan, pp. 35–49, 1999.
17. Caton J. A., “Operation characteristics of a spark–ignition engine using the second law of thermodynamics: effects of speed and load,” SAE World Congress, Detroit, Michigan, pp. 1–17, 2000.
18. Sohret Y., Gürbüz H. and Akçay I. H., “Energy and exergy analyses of a hydrogen fueled SI engine: effect of ignition timing and compression ratio,” Energy, 175, 410–422, 2019.
19. Sezer I. and Bilgin A., “Exergy analysis of SI engines,” International Journal of Exergy, 5(2), 204–217, 2008.
20. Ferguson C. R., “Internal combustion engine, applied thermosciences,” New York: John Wiley & Sons Inc., 1985.
21. Sezer I., “Application of exergy analysis to spark ignition engine cycle,” PhD Dissertation, Blacksea Technical University, Trabzon, Turkey, 2008.
22. Blizard N. C. and Keck J. C., “Experimental and theoretical investigation of turbulent burning model for internal combustion engines,” Society of Automotive Engineers, SAE Paper no 740191, 846864, 1974.
23. Keck J. C., “Turbulent flame structure and speed in spark–ignition engines,” International Nineteenth Symposium on Combustion, the Combustion Institute, 19(1), 14511466, 1982.
24. Tabaczynski R. J., Ferguson C. R. and Radhakrishnan K., “A turbulent entrainment model for sparkignition combustion,” Society of Automotive Engineers, SAE paper no 770647, 24142432, 1977.
25. Tabaczynski R. J., Trinker F. H. and Sahnnon B. A. S., “Further refinement of a turbulent flame propagation model for spark–ignition engines,” Combustion and Flame, 39, 111121, 1980.
26. Bayraktar H. and Durgun O., “Mathematical modeling of sparkignition engine cycles,” Energy Sources, 25, 651666, 2003.
27. Gülder Ö., “Correlations of laminar combustion data for alternative S.I. engine fuels,” Society of Automotive Engineers, SAE paper no 841000, 123, 1984.
28. Bilgin A., “Geometric features of the flame propagation process for an SI engine having dual–ignition system,” International Journal of Energy Research, 26, 9871000, 2002.
29. Cengel Y. A. and Boles M. A., “Thermodynamics, an engineering approach: 2nd edition,” New York: McGraw–Hill Inc., 1994.
30. Rezac P. and Metghalchi H., “A brief note on the historical evolution and present state of exergy analysis,” International Journal of Exergy, 1(4), 426437, 2004.
31. Van Gerpen J. H. and Shapiro H. N., “Second law analysis of diesel engine combustion,” Transaction of ASME Journal of Engineering Gas Turbines and Power, 112, 129137, 1990.
32. Caton J. A., “Results from the second–law of thermodynamics for a spark–ignition engine using a cycle simulation,” Proceedings of the ASME–ICED Fall Technical Conference, Ann Arbor, Michigan, pp. 3549, 1999.
33. Caton J. A., “Operation characteristics of a spark–ignition engine using the second law of thermodynamics: effects of speed and load,” SAE World Congress, Detroit, Michigan, pp. 117, 2000.
34. Zhang S., “The second law analysis of a spark ignition engine fueled with compressed natural gas,” MS Dissertation, University of Windsor, Ontario, Canada, 2002. Kotas T. J., “The exergy method of thermal plant analysis,” Malabar: Krieger Publishing, 1995.