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A Variable-Displacement Spark-Ignition Engine
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1977 by SAE International in United States
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A five-cylinder variable displacement research engine has been designed, built, and tested for over one year. Displacement is varied by changing the piston stroke using a four-bar linkage. By proper choice of the linkage dimensions, compression ratio can be held constant as the stroke changes, or it can be tailored to optimize economy and performance. Before the engine was built, its dynamics were thoroughly analyzed, and a five-cylinder configuration was selected to minimize vibration. Test data show that BSFC is, as expected, less dependent on load than in conventional engines, and averages less than 0.5 lb/bhp-hr over the load and speed range of ordinary automobile operation. Several methods for estimating urban fuel economy from dynamometer data predict a significant improvement compared with conventional engines. Emission controls have not yet been applied to this engine.
CitationPouliot, H., Delameter, W., and Robinson, C., "A Variable-Displacement Spark-Ignition Engine," SAE Technical Paper 770114, 1977, https://doi.org/10.4271/770114.
- Pierce J., “Variable Stroke Mechanisms,” U. S. Patent No. 1,112,832, October 6, 1914.
- Rietti G., “Combustion-Engine,” U. S. Patent No. 1,095,675, May 5, 1914.
- Biermann A. E., “Variable Stroke Piston Engines,” U. S. Patent No. 2,909,163, October 20, 1959.
- Welsh H. W. and Riley C. T., “The Variable Displacement Engine: An Advanced Concept Power Plant,” Paper 710830 presented at SAE National Combined Fuels and Lubricants, Power-plant and Truck Meetings, St. Louis, October 26-29, 1971.
- Hopkins H., Personal Communication.
- Taylor C. F., “The Internal-Combustion Engine in Theory and Practice,” Vol. II, Chapter 8, MIT Press, Cambridge, Massachusetts, 1968.
- Spindt R. S., “Air-Fuel Ratios from Exhaust Gas Analysis,” SAE Trans. V. 74, 1965.
- “Code of Federal Regulations, Title 40, Protection of Environment, Parts 70 to 99, as of July 1, 1975,” CFR 86.777-15, U. S. Government Printing Office, 1975.
- Stivender D. L., “Development of a Fuel Based Mass Emission Measurement Procedure,” SAE Paper 710604.
- Eltinge L., “Fuel-Air Ratio and Distribution from Exhaust Gas Composition,” SAE Paper 680114, pp. 425-450.
- Vanderbrug T., Jet Propulsion Laboratories, Private Communication.