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Variable Valve Closure Timing for Load Control and the Otto Atkinson Cycle Engine
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Abstract
Two fundamental methods of improving the brake specific fuel consumption of a spark ignition engine at part load have been investigated. These comprise the reduction of pumping losses by variable intake valve timing and changes of clearance volume to increase the expansion ratio. The resulting Otto-Atkinson cycle engine competes with the Diesel cycle engine.
Test bed results from a four cylinder engine are reported which largely confirm previous predictions from thermodynamic cycle simulation. The interactive effects between cylinders on pumping loss and mixture requirements are discussed.
These results show that brake specific fuel consumption improvements of up to 13% are obtainable from variable valve closure delay alone at some operating points over the usual range of speed and load, and that an additional variable clearance volume control can increase this to a maximum of 20%. It is noted that possible requirements for good manifold design may be different from those in current conventional engines.
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Authors
Citation
Saunders, R. and Abdul-Wahab, E., "Variable Valve Closure Timing for Load Control and the Otto Atkinson Cycle Engine," SAE Technical Paper 890677, 1989, https://doi.org/10.4271/890677.Also In
References
- Lichty, L. “Combustion Engine Processes” McGraw Hill New York 1967
- Patrick, M. “The sad tale of Edward LaForce and his revolutionary engine” Car and Driver April 1979
- Luria, D. Taitel, Y. Stotter, A. “The Otto-Atkinson Engine, a new concept in automotive economy” SAE Paper 820352
- Tuttle, J. H. “Controlling Engine Load by Means of Late Intake valve Closing” SAE Paper 800794
- Tuttle, J. H. “Controlling Engine Load by Means of Early intake valve closing” SAE Paper 820408
- Saunders, R. J. Rabia, S. M. “Part Load Efficiency in Gasoline Engines” Instn. Mech. Engrs. Seminar on Practical Limits of Efficiency of Engines 1986
- Saunders, R. J. “Atkinson Cycle - Spark Ignition Engines” Int. J. of Vehicle Design, IAVD Congress on Vehicle Design and Components Geneva 1984
- Benson, R. S. Baruah, P. C. “Performance and Emission Prediction for a Multi-cylinder Spark Ignition Engine” Instn. Mech, Engrs. Proc. 1977 191 32 77
- Rabia, S. M. University of Sheffield 1988
- Benson, R. S. Annand, W. J. D. Baruah, P. C. “A simulation Model Including intake and Exhaust Systems for a single cylinder four-stroke cycle spark ignition engine” Int. J. Mech. Sci. 1975 17 97 124
- Annand, W. J. D. “Heat Transfer in the Cylinders of Reciprocating Internal Combustion Engines” Inst. Mech. Engrs. Proc. 1963 177 36
- James, E. H. “Some aspects of compression ratio increase on spark ignition engine combustion” Inst. Mech. Engrs. Seminar on Practical Limits of Efficiency of Engines 1986
- Caris, D. F. Nelson, E. E. “A new look at High Compression Engines” SAE Transactions 1959 67 112 124
- Emslie, C. Rushworth, M. University of Sheffield, Department of Mechanical Engineering 1983
- Keck, J. C. Heywood, J. B. Noske, G. “Early flame development and burning rates in spark ignition engines and their cyclic variability” SAE Paper 870164
- Eisele, H. P. Weiss, E. “Applicability of an uncooled pressure pick-up” MTZ 46 1985 11 445 448
- Muller, H. Winter, B. Roude-Brandenberger, K. “Comparative experiments with Piezoelectric Pressure Transducers to Determine their Suitability for use in Combustion Engines” MTZ 1986 1