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Computerized Knock Detection from Engine Pressure Records
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English
Abstract
THE WORK REPORTED in this paper is part of an on-going study of cyclic variability in spark-ignition engines. In order to analyze knock and its variability from cycle to cycle in a meaningful way, an algorithm has been developed to characterize the severity of the bulk pressure change associated with knocking combustion. This algorithm depends on the third differential of pressure over the period when autoignition might occur. A large negative value of third differential indicates the abrupt pressure rise and narrow pressure peak commonly associated with end gas autoignition. This knock diagnostic has the advantage of working on a low frequency data acquisition rate (1 point/CA° or less) and of producing consistent results in spite of high frequency noise on the pressure signal such as might be caused by resonance of a spark plug-mounted pressure transducer.
The proposed Knock Indicator is applied to data from a low speed Waukesha C.F.R. engine and is compared with several other pressure trace parameters to establish its validity as a knock diagnostic. It is shown that the Knock Indicator consistently predicts the degree of abrupt pressure rise associated with end-gas autoignition and thus is a suitable algorithm for monitoring the severity of knock as well as its occurrence. The method is suitable for use within most research programs which use routine engine cycle analysis as it adds knock severity measurement without any additional equipment or operational constraints. The low computational requirement may also make the method useful for future on-board combustion diagnostic systems.
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Citation
Checkel, M. and Dale, J., "Computerized Knock Detection from Engine Pressure Records," SAE Technical Paper 860028, 1986, https://doi.org/10.4271/860028.Also In
References
- Oppenheim A.K. “The Knock Syndrome-Its Cures and Its Victims.” SAE Paper No. 841339 Fuels and Lubricants Meeting Baltimore 1984
- Thring R.H. “Gasoline Engines and Their Future.” Mechanical Engineering, A.S.M.E. October 1983 40
- Kando M. Nimi A. Nakamuro T. “Indiscope-A New Combustion Pressure Indicator with Washer Transducers.” SAE Paper No. 750883 Automobile Engineering Meeting Detroit 1975
- Randall K.W. Powell J.D. “A Cylinder Pressure Sensor for Spark Advance Control and Knock Detection.” SAE Paper No. 790139 SAE Transactions 88 508 1979
- Miyamoto N. Murayama T. Gotah S. “Unique Measuring Method of Indicator Diagrams Using Strain History of Head Bolts.” SAE Paper No. 800983 Off Highway Meeting Milwaukee 1980
- Fleming W.J. “Engine Sensors-State of the Art.” SAE Paper No. 820904 SAE Transactions 91 3004 1982
- Morris J.E. Anderson H. Smith R. “Retrofit Feedback Control of A/F Ratio and Ignition Timing for Fuel Economy.” SAE Paper No. 820389 SAE Transactions 91 1559 1982
- Morris J.E. Li-Chi “Improved Intra-Cylinder Combustion Pressure Sensor.” SAE Paper No. 850374 1985 11
- Draper C.S. “Pressure Waves Accompanying Detonation in the Internal Combustion Engine.” Jrnl of the Aero Sco. 5 6 219 1938
- Evers L.W. “Spark Plug Pressure Transducers for Measuring Indicated Work.” SAE Paper No. 780148 SAE Congress Detroit 1978
- Barton R.K. Letz S.S. Duke L.C. “Knock Intensity as a Function of Engine Rate of Pressure Change.” SAE Paper No. 700061 January 1971
- Wolber W.G. Ebaugh P.J. “Automotive Engine Control Sensors ′85.” SAE Paper No. 850491 1985 101
- Arrigoni V. Cornetti G. Gaetani B. Ghezzi P. “Quantitative Systems for Measuring Knock.” Proc. Inst. Mech. Engrs., Automobile Div. 186 48/72 575 1972
- Ferraro C.V. Marzano M. Nuccio P. “Knock-Limit Measurement in High-Speed S. I. Engines.” SAE Paper No. 850127 SAE Congress Detroit 1985
- Leppard W.R. “Individual-Cylinder Knock Occurrence and Intensity in Multicylinder Engines.” SAE Paper No. 820074 SAE Congress Detroit 1982