This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Swirl, Fuel Composition, Localized Heating, and Deposit Effects on Engine Knock Location
Annotation ability available
Sector:
Language:
English
Abstract
In this investigation, recently developed techniques to locate knock origins were applied to study fuel and deposit effects as they interact with charge motion. Particularly, the individual and interactive effects of swirl, fuel composition, localized heating, and deposits on in-cylinder knock origin were studied. A Waukesha Split Head CFR engine was modified to accept four pressure transducers for calculating by triangulation the cycle resolved in-cylinder origin of engine knock. Location of the origin of knock within the combustion chamber was based on the difference in time for each pressure transducer to register the onset of knock during the combustion cycle. Computer software was developed and optimized to maximize the success rate in locating knock within 1 cm. In order to explore the difference in location of knock due to fluid dynamics within the cylinder, the shrouded intake valve of the engine was modified to create different swirl conditions within the combustion chamber. Tests for knock location were performed under counterclockwise, clockwise, and no swirl conditions. Isooctane/n-heptane and toluene/n-heptane blends were tested to determine what differences in knock location are attributable to branched-paraffin/straight-chained paraffin versus aromatic/straight-chained paraffin chemistries. Tests were also performed to investigate the influence of localized heating within the combustion chamber on knock origin. A glow plug was inserted into the combustion chamber and data was collected at several compression ratios and power inputs to the glow plug. Finally, the effects of combustion chamber deposits on knock were investigated. Deposits were allowed to build up within the cylinder by running a deposit forming engine cycle. Tests were then performed at various knock intensities to discover the influence of those deposits on the location of in-cylinder knock origin. The effects of all the above mentioned parameters and their implications on the phenomena of engine knock are discussed.
Recommended Content
Technical Paper | Knock (Detonation) Control by Engine Combustion Chamber Shape |
Technical Paper | An Experimental Study on Knock Sensing for a Spark Ignition Engine |
Technical Paper | A Contribution to Knock Statistics |
Citation
Liiva, P., Cobb, J., and Acker, W., "Swirl, Fuel Composition, Localized Heating, and Deposit Effects on Engine Knock Location," SAE Technical Paper 932814, 1993, https://doi.org/10.4271/932814.Also In
References
- Liiva P. M. Valentine J. N. Cobb J. M. Acker W. P. “Use of Multiple Pressure Transducers to Find In-Cylinder Knock Location,” SAE paper 922368
- Midgely T. Boyd A. “Methods of Measuring Detonation in Engines,” SAE Trans. 17 Part 1 1922
- Draper C. S. “Pressure Waves Accompanying Detonation in the Internal Combustion Engine,” J. Aeronaut. Sci. 5 219 226 1938
- Maly T. “Photography at 500,000 Frames per Second of Combustion and Detonation in a Reciprocating Engine,” Proceedings of the Third Symposium on Combustion, Flame, and Explosion Phenomena 721 Williams and Wilkins, Combustion Institute, Pittsburgh 1949
- Hayashi T. Taki M. Kojima S. Kondo T. “Photographic Observation of Knock with a Rapid Compression and Expansion Machine,” SAE paper 841336
- Nakaqawa Y. Takagi Y. Itoh T. Iijima T. “Laser Shadowgraphic Analysis of Knocking In S.I. Engine,” SAE paper 845001
- Spicher U. Kröger H. Ganser J. “Detection of Knocking Combustion Using Simultaneously High-Speed Schlieren Cinema and Multi Optical Fiber Technique,” SAE paper 912312
- Checkel M. D. Dale J. D. “Computerized Knock Detection from Engine Pressure Records,” SAE paper 860028
- Checkel M. D. Dale J. D. “Pressure Trace Knock Measurement in a Current S.I. Production Engine,” SAE paper 860243
- Chun K. M. Heywood J. B. “Characterization of Knock in a Spark Ignition Engine,” SAE paper 890156
- Puzinauskas P. P. “Examination of Methods Used to Characterize Engine Knock,” SAE paper 920808
- Leppard W. R. “The Autoignition Chemistry of Isobutane: A Motored Engine Study,” SAE paper 881606
- Leppard W. R. “The Chemical Origin of Fuel Octane Sensitivity,” SAE paper 902137
- Pitz W. J. Westbrook C. K. Leppard W. R. “Autoignition Chemistry of N-Butane in a Motored Engine: A Comparison of Experimental and Modeling Results,” SAE paper 881605
- Westbrook C. K. Pitz W. J. Leppard W. R. “The Autoignition Chemistry of Paraffinic Fuels and Pro-Knock and Anti-Knock Additives: A Detailed Chemical Kinetic Study,” SAE paper 912314
- Pitz W. J. Westbrook C. K. Leppard W. R. “Autoignition Chemistry of C 4 Olefins Under Motored Engine Conditions: A Comparison of Experimental and Modeling Results,” SAE paper 912315
- Green R. M. Cernansky N. P. Pitz W. J. Westbrook C. K. “The Role of Low Temperature Chemistry in the Autoignition of N-Butane,” SAE paper 872108
- Wilk R. D. Green R. M. Pitz W. J. Westbrook C. K. Addagarla S. Miller D. L. Cernansky N. P. “An Experimental and Kinetic Modeling Study of the Combustion of n-Butane and Isobutane in an Internal Combustion Engine,” SAE paper 900028
- Adams K. M. Baker R. E. “Effects of Combustion Chamber Deposit Locations and Composition,” Symposium on Chemistry of Engine Combustion Deposits, Presented Before the Division of Petroleum Chemistry, Inc., American Chemical Society, Atlanta Meeting March 29 - April 3, 1981 555 564
- Graiff L. B. “Some New Aspects of Deposit Effects on Engine Octane Requirement Increase and Fuel Economy,” SAE paper 790938
- Benson J. D. “Some Factors Which Affect Octane Requirement Increase,” SAE paper 750933
- Curry S. “A Three Dimensional Study of Flame Propagation in a Spark Ignition,” SAE Paper No. 452B 1962