This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
The Potential of the Variable Stroke Spark-Ignition Engine
Annotation ability available
Sector:
Language:
English
Abstract
A comprehensive quasi-dimensional computer simulation of the spark-ignition (SI) engine was used to explore part-load, fuel economy benefits of the Variable Stroke Engine (VSE) compared to the conventional throttled engine. First it was shown that varying stroke can replace conventional throttling to control engine load, without changing the engine characteristics. Subsequently, the effects of varying stroke on turbulence, burn rate, heat transfer, and pumping and friction losses were revealed. Finally these relationships were used to explain the behavior of the VSE as stroke is reduced. Under part load operation, it was shown that the VSE concept can improve brake specific fuel consumption by 18% to 21% for speeds ranging from 1500 to 3000 rpm. Further, at part load, NOx was reduced by up to 33%. Overall, this study provides insight into changes in processes within and outside the combustion chamber that cause the benefits and limitations of the VSE concept.
Recommended Content
Authors
Topic
Citation
Alsterfalk, M., Filipi, Z., and Assanis, D., "The Potential of the Variable Stroke Spark-Ignition Engine," SAE Technical Paper 970067, 1997, https://doi.org/10.4271/970067.Also In
References
- Pierce, J. “Variable Stroke Mechanisms,” October 6 1914
- Biermann, A. E. “Variable Stroke Piston Engines,” October 20 1959
- Welsh, H. W. Riley C. T. “The Variable Displacement Engine: An Advanced Concept Power Plant,” SAE Paper 710830 October 1971
- Pouliot, H. N. Delameter W. R. Robinson C. W. “A Variable Displacement Spark Ignition Engine,” SAE Paper 770114 February 1977
- Siegla, D. C. Siewert R. M. “The Variable Stroke Engine - Problems and Promises,” SAE Paper 780700 August 1978
- Siewert, R. M. “Engine Combustion at Large Bore-to-Stroke Ratios,” SAE Paper 780968 1978
- Filipi, Z. Assanis, D. N. “Quasi-Dimensional Computer Simulation of the Turbocharged Spark-Ignition Engine and its Use for 2- and 4-Valve Engine Matching Studies,” SAE Paper 910075 SAE Transactions 1991
- Filipi Z. S. Assanis D. N. “On Determining the Optimum Stroke-to-Bore Ratio for A Spark Ignition Engine of Given Displacement,” XXVI FISITA Congress Prague June 1996
- Tabaczynski, R. J. Ferguson, C.R. Radhakrishnan, K. “A Turbulent Model for Spark-Ignition Engine Combustion,” SAE Paper 770647 SAE Transactions 86 1977
- Tabaczynski R. J. Trinker F. H. Shannon B. A. “Further Refinement and Validation of a Turbulent Flame Propagation Model for Spark-Ignition Engines,” Combustion and Flame 39 2 111 121 1980
- Poulos, S. G. Heywood, J. B. “The Effect of Chamber Geometry on Spark Ignition Engine Combustion,” SAE Paper 830334 SAE Transactions 92 1983
- Stoddart, D. A. “Polydyne Cam Design, Parts I, II and III,” Machine Design Jan.-Feb.-March 1953
- Assanis, D. Polishak, M. 1990 “Valve Event Optimization in a Spark Ignition Engine,” ASME Transactions, Journal of Engineering for Gas Turbines and Power 112 3 341 347
- Noyes, R. “Analytical Prediction of Discharge Coefficients for Engine Poppet Valves,” GM Research Publication GMR-3376 Warren, MI 1980
- Komiyama, K. Heywood, J.B “Predicting NOx Emissions and Effect of Exhaust Gas Recirculation in Spark-Ignition Engines,” SAE Paper 730475 SAE Transactions 82 1973
- Patton, K. J. Nitchke, R. G. Heywood, J. B. “Development and Evaluation of a Friction Model for Spark-Ignition Engines,” SAE Paper 890836 1989