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Cycle-by-Cycle Variations of a Spark Ignition Engine - A Statistical Analysis
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Sector:
Event:
Mid-Year Meeting
Language:
English
Abstract
The cycle-by-cycle combustion variation as reflected by the pressure development of a single cylinder, spark ignition, internal combustion engine is discussed. The data originated from a CFR-RDH engine which was instrumented with a pressure transducer whose signal was modified and digitized for statistical analysis of peak pressure, peak rate of pressure change, and crank angles at which peak pressure and peak rate of pressure changes occurred. These parameters were analyzed for averages, standard deviations, and cross-correlations. In addition, auto-correlations were made of peak pressure. A study was conducted on the effects of charge homogeneity using the F-test, and Bartlett's test was used to determine if significant changes in the standard deviations occurred with changes in engine conditions.
The results indicate that significant differences in the standard deviations of the four pressure development parameters exist for different engine operating conditions. Suggested variations in the combustion process are then inferred from these significant differences The inferences made are with respect to the average flame speed, the variations in flame speed and the phasing of the combustion process. While it is shown how engine operating variables affect cycle-by-cycle variations, evidence is also presented to establish that these variations are random.
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Authors
- R. K. Barton - Dept. of Mechanical Engineering, The Pennsylvania State University
- D. K. Kenemuth - Dept. of Mechanical Engineering, The Pennsylvania State University
- S. S. Lestz - Dept. of Mechanical Engineering, The Pennsylvania State University
- W. E. Meyer - Dept. of Mechanical Engineering, The Pennsylvania State University
Citation
Barton, R., Kenemuth, D., Lestz, S., and Meyer, W., "Cycle-by-Cycle Variations of a Spark Ignition Engine - A Statistical Analysis," SAE Technical Paper 700488, 1970, https://doi.org/10.4271/700488.Also In
References
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- Soltau J. P. “Cylinder Pressure Variations in Petrol Engines.” Proceedings of Automotive Division London Institute of Mechanical Engineers 2 1960-61 99
- Troutman C. L. Lestz S. S. “Exhaust Emissions and Cycle-to-Cycle Irregularities.” Automotive Safety Research Program The Pennsylvania State University June 1969
- Harrow G. A. Orman P. L. “A Study of Flame Propagation and Cyclic Dispersion in a Spark-Ignition Engine.” Proceedings of the Fourth Symposium ASME Crenfield July 1965
- Curry Shelly “A Three Dimensional Study of Flame Propagation in a Spark-Ignition Engine.” SAE Transactions 71 1963 628 650
- Eltinge Lamont “Fuel-Air Ratio and Distribution from Exhaust Gas Composition.” Paper 680114 SAE Automotive Engineering Congress Detroit January 1968
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- Neville A. M. Kennedy J. B. “Basic Statistical Methods for Engineers and Scientists.” Scranton, Pa. International Textbook Co. 1964
- Spiegel M. R. “Theory and Problems of Statistics.” New York Schaum Publishing Co. 1961
- Barton R. K. Lestz S. S. Duke L. C. “Knock Intensity as a Function of Engine Rate of Pressure Change.” Paper 700061 SAE Automotive Engineering Congress Detroit January 1970
- Kenemuth D. K. Lestz S. S. “Charge Conditioning Effects on Cycle-by-Cycle Pressure Development Variations of an SI Engine.” Automotive Safety Research Program The Pennsylvania State University March 1970