Document Type: Original Article

Authors

1 The Faculty of Engineering, Mechanical Engineering Department, Ferdowsi University of Mashhad, Mashhad, Iran

2 The Faculty of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran.

Abstract

There has been an increasing interest in the enhancement the efficiency and functionality of engines, particularly petrol ones, in recent years. In this paper, four stroke spark ignition internal combustion engine cycle has been simulated based on first law of thermodynamics. The second law analysis has also been conducted to analyse the effects of ignition timings, combustion duration as well as engine speed upon engine efficiency and performance. The availability (exergy) balance equations of the engine cylinder has been considered in detail. Moreover, total availability fractions and process irreversibilities have been evaluated. By considering the results for brake and indicated mean effective pressure, it is shown that they behave in an opposite way in terms of increasing engine speeds. After perusing the figures, a conclusion is made, revealing that exergetic efficiency rises by increasing engine speed, whereas the opposite is true for brake thermal efficiency. Furthermore, The optimum point in which total efficiency ( both thermal and exergetic) shows the highest possible level happens at the speed of 2500 rpm

Keywords

Main Subjects

[1] Abd Alla, G.H., Computer Simulation of a Four Stroke Spark Ignition Engine, Energy Conversion and Management 43 (2002) 1043–1061.

[2] Farzaneh-Gord M., Maghrebi, M. J., Hajializadeh, H., Optimizing Four Stroke Spark Ignition Engine Performance, The second International conference on Modeling, Simulation, And Applied optimization, Abu Dhabi, UAE, March 24-27 2007.

[3] Stone, Richard, Introduction to Internal Combustion Engines, Department of Engineering Science, University of Oxford, 1999.

[4] Rakopoulos, C.D. and Kyritsis D.C., Comparative Second-Law Analysis of Internal Combustion Engine Operation for Methane, Methanol, and Dodecane Fuels, Energy 26 (2001) 705–722.

[5] Sobiesiak, A. and Zhang, S., the First and Second Law Analysis of Spark Ignition Engine Fuelled with Compressed Natural Gas, SAE International. 2003-01-3091.

[6] Rakopoulos, C. D., Giakoumis, E. G., Second-law Analyses Applied to Internal Combustion Engines Operation, Energy and Combustion Science 32 (2006) 2–47.

[7] Kopac, M. and Kokturk, L., Determination of Optimum Speed of an Internal Combustion Engine by Exergy Analysis, Int. J. Exergy, Vol. 2, No. 1, 2005.

[8] Heywood, John B, ” Internal Combustion Engine Fundamentals”, McGraw-Hill, Inc. 1988.

[9] Willard W. Pulkrabek,” Engineering fundamentals of internal combustion engine”,1997.

[10]­­­­­ Winterbone D., Advanced Thermodynamics for Engineers, Thermodynamics and Fluid Mechanics Division Department of Mechanical Engineering UMIST,1997.

[11] Moran, M. J., Shapiro, H. N., Boettner, D. D., & Bailey, M. B. Fundamentals of engineering thermodynamics. John Wiley & Sons, 2010.

[12] Ismet Sezer , Atilla Bilgin, Exergy analysis of SI engines, International Journal of Exergy 2008 - Vol. 5, No.2 pp. 204 - 217.

[13] Branes-Moss HW., A designer’s viewpoint, in passenger car engines, Conference Proceedings, Institution of Mechanical Engineers, London, 1975. p. 133–47.

[14] John B.Heywood,” Internal Combustion Engine Fundamentals”, McGraw-Hill, Inc. 1988.