0
Research Papers: Internal Combustion Engines

# Thermodynamic Considerations Related to Knock: Results From an Engine Cycle Simulation

[+] Author and Article Information
Jerald A. Caton

Department of Mechanical Engineering,
Texas A&M University,
College Station, TX 77843–3123

1Although autoignition may occur without knock, knock requires autoignition.

2A small amount of knock, however, may be beneficial relative to performance since the last small amount of fuel is consumed rapidly.

Contributed by the IC Engine Division of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received February 19, 2018; final manuscript received February 26, 2018; published online May 29, 2018. Editor: David Wisler.

J. Eng. Gas Turbines Power 140(9), 092805 (May 29, 2018) (8 pages) Paper No: GTP-18-1078; doi: 10.1115/1.4039750 History: Received February 19, 2018; Revised February 26, 2018

## Abstract

The design and development of high efficiency spark-ignition engines continues to be limited by the consideration of knock. Although the topic of spark knock has been the subject of comprehensive research since the early 1900s, little has been reported on the coupling of the engine thermodynamics and knock. This work uses an engine cycle simulation together with a submodel for the knock phenomena to explore these connections. First, the autoignition characteristics as represented by a recent (2014) Arrhenius expression for the reaction time of the end gases are examined for a range of temperatures and pressures. In spite of the exponential dependence on temperature, pressure appears to dominate the ignition time for the conditions examined. Higher pressures (and higher temperatures) tend to enhance the potential for knock. Second, knock is determined as function of engine design and operating parameters. The trends are consistent with expectations, and the results provide a systematic presentation of knock occurrence. Engine parameters explored include compression ratio, engine speed, inlet pressure, start of combustion, heat transfer, and exhaust gas recirculation (EGR). Changes of cylinder pressures and temperatures of the unburned zone as engine parameters were varied are shown to be directly responsible for the changes of the knock characteristics.

<>

## References

Heywood, J. B. , 1988, Internal Combustion Engine Fundamentals, McGraw-Hill, New York.
Midgley, T., Jr. , 1920, “ Combustion of Fuels in Internal-Combustion Engine,” SAE J., 7, pp. 489–499.
Miller, C. D. , 1947, “ Roles of Detonation Waves and Autoignition in Spark-Ignition Engine Knock as Shown by Photographs Taken at 40,000 and 200,000 Frames Per Second,” SAE Q. Trans., 1, pp. 98–143.
Livengood, J. C. , and Wu, P. C. , 1955, “ Correlation of Autoignition Phenomena in Internal Combustion Engines and Rapid Compression Machines,” Fifth International Symposium on Combustion, Pittsburgh, PA, Aug. 30–Sept. 3, pp. 347–356.
Halstead, M. P. , Kirsch, L. J. , and Quinn, C. P. , 1977, “ The Autoignition of Hydrocarbon Fuels at High Temperatures and Pressures—Fitting of a Mathematical Model,” Combust. Flame, 30, pp. 45–60.
Cox, R. A. , and Cole, J. A. , 1985, “ Chemical Aspects of the Autoignition of Hydrocarbon-Air Mixtures,” Combust. Flame, 60(2), pp. 109–123.
Cowart, J. S. , Keck, J. C. , Heywood, J. B. , Westbrook, C. K. , and Pitz, W. J. , 1990, “ Engine Knock Predictions Using a Fully-Detailed and a Reduced Chemical Kinetic Mechanism,” Twenty-Third International Symposium on Combustion, Orléans, France, July 22–27, pp. 1055–1062.
Litzinger, T. A. , 1990, “ A Review of Experimental Studies of Knock Chemistry in Engines,” Prog. Energy Combust. Sci., 16(3), pp. 155–167.
Mittal, V. , Bridget, M. R. , and Heywood, J. B. , 2007, “ Phenomena That Determine Knock Onset in Spark-Ignition Engines,” SAE Paper No. 2007-01-0007.
Douaud, A. M. , and Eyzat, P. , 1978, “ Four-Octane-Number Method for Predicting the Anti-Knock Behavior of Fuels and Engines,” SAE Paper No. 780080.
Hoepke, B. , Jannsen, S. , Kasseris, E. , and Cheng, W. K. , 2012, “ EGR Effects on Boosted SI Engine Operation and Knock Integral Correlation,” SAE Int. J. Engines, 2, pp. 547–559.
Chen, L. , Li, T. , Yin, T. , and Zheng, B. , 2014, “ A Predictive Model for Knock Onset in Spark-Ignition Engines With Cooled EGR,” Energy Convers. Manage., 87, pp. 946–955.
Caton, J. A. , 2016, An Introduction to Thermodynamic Cycle Simulations for Internal Combustion Engines, Wiley, Chichester, UK.
Caton, J. A. , 2015, “ Thermodynamic Comparison of External and Internal Exhaust Gas Dilution for High Efficiency IC Engines,” Int. J. Engine Res., 16(8), pp. 935–955.
Caton, J. A. , 2014, “ Thermodynamic Considerations for Advanced, High Efficiency IC Engines,” ASME J. Eng. Gas Turbines Power, 136(6), p. 101512.
Caton, J. A. , 2012, “ The Uses and Limitations of a Thermodynamic Cycle Simulation for Assessing Spark-Ignition Engine Design,” Int. J. Powertrains, 1(3), pp. 259–303.
Woschni, G. , 1968, “ A Universally Applicable Equation for the Instantaneous Heat Transfer Coefficient in the Internal Combustion Engine,” SAE Paper No. 670931.
Caton, J. A. , 2006, “ Utilizing a Cycle Simulation to Examine the Use of EGR for a Spark-Ignition Engine Including the Second Law of Thermodynamics,” ASME Paper No. ICEF2006-1508.
Shyani, R. G. , and Caton, J. A. , 2009, “ A Thermodynamic Analysis of the Use of EGR in SI Engines Including the Second Law of Thermodynamics,” Proc. Inst. Mech. Eng., Part D, 223(1), pp. 131–149.
Elmqvist, C. , Lindstrom, F. , Angstrom, H.-E. , Grandin, B. , and Kalghatgi, G. , 2003, “ Optimizing Engine Concepts by Using a Simple Model for Knock Prediction,” SAE Paper No. 2003-01-3123.
Caton, J. A. , 2011, “ Comparisons of Global Heat Transfer Correlations for Conventional and High Efficiency Reciprocating Engines,” ASME Paper No. ICEF2011-60017.
Annand, W. J. D. , 1963, “ Heat Transfer in the Cylinders of Reciprocating Internal Combustion Engines,” Proc. Inst. Mech. Eng., 177(1), pp. 973–996.
Hohenberg, G. F. , 1979, “ Advanced Approaches for Heat Transfer Calculations,” SAE Paper No. 790825.

## Figures

Fig. 1

The reaction time from Chen et al. [12] correlation as a functions of pressure for temperatures of 500, 600, and 1000 K. The cases for compression ratios of 4, 8, and 12 are denoted with the circles.

Fig. 2

The accumulated time and the composite reaction time as functions of crank angle for compression ratios of 7, 8, and 12

Fig. 3

The knock integral as functions of crank angle for compression ratios of 4, 6, 8, and 12

Fig. 4

The knock intensity as functions of the compression ratio for engine speeds of 1000 and 1500 rpm

Fig. 5

The knock integral as a functions of crank angle for engine speeds of 1000, 1500, and 2000 rpm

Fig. 6

The knock integral as functions of crank angle for inlet pressures of 75, 85, and 95 kPa

Fig. 7

The knock integral as a function of crank angle for cooled EGR levels of 0%, 15%, and 30% for the case with an engine speed of 1000 rpm and a compression ratio of 10

Fig. 8

The bmep as functions of cooled EGR for the 1000 rpm and 10 compression ratio case

Fig. 9

The knock integral as a function of crank angle for adiabatic EGR levels of 0%, 15%, and 30% for the case with an engine speed of 1000 rpm and a compression ratio of 10

Fig. 10

The knock integral as a functions of crank angle for the base case for three correlations for the reaction time

Fig. 11

The knock integral as a functions of crank angle for the base case for three correlations for the cylinder heat transfer

## Discussions

Some tools below are only available to our subscribers or users with an online account.

### Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related Proceedings Articles
Related eBook Content
Topic Collections