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Fluid Dynamic Study of Unthrottled Part Load SI Engine Operations with Asymmetric Valve Lifts
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 13, 2009 by Consiglio Nazionale delle Ricerche in Italy
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This paper describes how a fully three-dimensional CFD model was used to investigate the turbulence generation mechanisms of an unthrottled 4 valve SI engine operating with different intake valve lift strategies (symmetric and asymmetric). In the context of Early Intake Valve Closure (EIVC) strategies, the aim of the work is to highlight the potentialities to increase turbulence levels also at light load using asynchronous intake valve lift, thus promoting both tumble and swirl motions.
Six simulations are presented, four at low engine speed (2500 rpm) and two at high speed (6000 rpm, that serve as reference), concerning an SI engine at full and light load, with symmetric and asymmetric intake lifts. One of these simulations was executed in standard throttling conditions.
The CFD transient simulations involved three strokes of the engine: exhaust, intake and compression up to combustion TDC. 1D data are used for boundary and initial conditions. Experimental steady state flow test data are also used for a preliminary assessment of the CFD model capability.
It is shown that, at equal engine load achieved with EIVC strategies, the case with a single valve lift yields higher turbulence intensities than dual symmetric lifts.
CitationBattistoni, M. and Mariani, F., "Fluid Dynamic Study of Unthrottled Part Load SI Engine Operations with Asymmetric Valve Lifts," SAE Technical Paper 2009-24-0017, 2009, https://doi.org/10.4271/2009-24-0017.
- Arcoumanis, C. Hu, Z. Whitelaw, J. H. ‘Steady flow characterization of tumble-generating four-valve cylinder heads’ Proc. Inst. Mech. Eng. Vol. 207 203 210 1993
- Heywood, J. B. “Internal Combustion Engine Fundamentals” McGraw Hill Book Company New York 1998
- Gosman, A. D. Tsui, Y. Y. Vafidis, C. ‘Flow in a Model Engine with a Shrouded Valve – a Combined Experimental and Computational Study' SAE paper 850498 1985
- Arcoumanis, C. Hu, Z. Vafidis, C. Whitelaw, J. H. ‘Tumbling Motion: a mechanism for turbulence enhancement in spark-igniton engines’ SAE paper 900060 1990
- Hadded, O. Denbratt, I. ‘Turbulence Characteristics of Tumbling air Motion in Four-Valve S.I. Engines and their Correlation with Combustion Parameters’ SAE paper 910478 1991
- Kern, Y. K. Seung M. O. Jin W. L. ‘The Effects of Tumble Flow on Lean Burn Characteristics in a Four-Valve SI Engine’ SAE paper 970791 1997
- Pischinger M. Salber W. Van Der Staay F. Baumgarten H Kemper H. “Benefits of the Electromechanical Valve Train in Vehicle Operation” SAE paper 2000-01-1223 2000
- Clearly D. Silvas G. “Unthrottled Engine Operation with Variable Intake Valve Lift, Duration, and Timing” SAE paper 2007-01-1282 2007
- Kim J. N. Kim H. Y. Yoon S. S. Sa S. D. “Effect of Intake Valve Swirl on Fuel-Gas Mixing and Subsequent Combustion in a CAI Engine” International Journal of Automotive Technology Vol. 9 No. 6 649 657 2008
- Bianchi G. M. Cantore G. Mattarelli E. Guerrini G. Papetti F. “The Influence of Stroke-to-Bore Ratio and Combustion Chamber Design on Formula One Engines Performance” SAE paper 980126 1998
- Baretzky U. Andor T. Diel H. Ullrich W. “The Direct Injection System of the 2001 Audi Turbo V8 Le Mans Engines” SAE paper 2002-01-3357 2002
- Grimaldi, C. N. Carducci, F. Postrioti, L. Bella, G. Rotondi, R. Vignaroli, G. “Dependence of High Performance Engine Modeling on Discharge Coefficient” High Tech Engines and Cars, 7th International Congress May 2001 Modena, Italy Proceedings on CD-ROM
- Postrioti, L. ‘Experimental Characterization of Discharge Coefficient and Tumble Motion in a Competition Engine Intake System’, High Tech Engines and Cars 8th International Congress May 2002 Modena, Italy Proceedings on CD-ROM
- Grimaldi, C. N. Battistoni, M. Postrioti, L. ‘Flow Characterization of a High Performance S.I. Engine Intake System – Part 1: Experimental Analysis’ SAE Technical Paper Series No. 2003-01-0623 2003
- Bella, G. De Maio, A. Grimaldi, C. N. “Flow Characterization of a High Performance S.I. Engine Intake System. Part 2: Numerical Analysis”, 2003 SAE World Congress, March 2003, Detroit, MI” SAE Paper 2003-01-0632 2003
- Grimaldi, C. N. Battistoni, M. Uccellani, M. ‘Dependence of Flow Characteristics of a High Performance S.I. Engine Intake System on Test Pressure and Tumble Generation Conditions – Part 1: Experimental Analysis’ SAE Technical Paper Series No. 2004-01-1530 2004
- Mariani F. Cavalletti M. ‘Dependence of Flow Characteristics of a High Performance S.I. Engine Intake System on Test Pressure and Tumble Generation Conditions – Part 2: Numerical Analysis’ SAE Technical Paper Series No. 2004-01-1531 2004
- Grimaldi C. N. Battistoni M. “Experimental Analysis of the Tumble Generation Process in the Intake System of a 4-Valve SI Engine” 10th International Conference High Tech Engines and Cars May 2004 Modena, Italy proceedings on CD-ROM
- Grimaldi, C. N. Battistoni, M. Mariani, F. “Experimental and Numerical Analysis of Charge Motion Characteristics Depending on Intake Valves Actuation Strategies‘” SAE Technical Paper Series No. 2005-01-0242 2005
- Battistoni M. Cancellieri A. Mariani, F. “Steady and Transient Fluid Dynamic Analysis of the Tumble and Swirl Evolution on a 4V Engine with Independent Intake Valves Actuation” SAE paper 2008-01-2392 2008
- Arcoumanis C. Godwin S.N. Kim J.W. “Effect of Tumble Strength on Combustion and Exhaust Emissions in a Single-cylinder, Four Valve, Spark-ignition Engine” SAE Paper 981044 1998
- Schechter M.M. Levin M.B. “Camless engine” SAE paper 960581 1996
- Sellnau M. Rask E. “Two-Step Variable Valve Actuation for Fuel Economy, Emissions, and Performance” SAE paper 2003-01-0029 2003
- Allen J. Law D. “Production Electro-Hydraulic Variable Valve-Train for a New Generation of I.C. Engines” SAE paper 2002-01-1109 2002
- Battistoni M. Mariani F. Postrioti L Grimaldi C.N. Cristiani M. Petrone M. Petrecchia S. “Numerical Analysis of a New Concept Variable Valve Actuation System” SAE paper 2006-01-3008 ; SAE 2006 Transactions - Journal of Engines 2006
- Avl List GmbH “AVL Boost Users Guide”, version 5.1.1 July 2008
- CD-Adapco “STAR-CD Ver. 4.06 Documentation” 2008
- Cancellieri A. “Analisi termofluidodinamica dell’evoluzione del moto della carica in motori alternativi a combustione interna tramite simulazioni cfd-3d non stazionarie con mesh mobile” PhD thesis Dep. of Industrial Engineering - Perugia University (Italy) 2009
- Lee K. Bae C Kang K. “The Effects of Tumble and Swirl Flows on Flame Propagation in a Four-Valve S.I. Engine” Applied Thermal Engineering (Elsevier) 2007 27 2122 2130
- Nagayama I. Araki Y. Iioka Y. “Effects of Swirl and Squish on S.I. Engine Combustion and Emission” SAE Paper 770217 1977