Keywords
optimization
VVA
SI engine
How to Cite
Abstract
Nowadays, modern internal combustion engines show more and more complex architectures in order to improve their performance. Referring to the spark-ignition (SI) engines, downsizing philosophy and Variable Valve Actuation (VVA) systems allow to reduce the Brake Specific Fuel Consumption (BSFC) at low and medium load, while maintaining the required performance at high load. On the other hand, the above solutions introduce additional degrees of freedom for the engine control, requiring longer calibration time and experimental effort.
In the present work, a twin-cylinder turbocharged VVA SI engine is numerically investigated by a one-dimensional (1D) model (GT-PowerTM). The considered engine is equipped with a fully flexible VVA actuation system, realizing an Early Intake Valve Closure (EIVC) strategy. Proper "user routines" are implemented in the code to simulate turbulence and combustion processes.
In a first stage, 1D engine model is validated against the experimental data under part load condition, both in terms of overall performance and combustion evolution. The validated 1D engine model is then integrated in a multipurpose commercial optimizer (mode FRONTIERTM) with the aim to identify the engine calibrations that simultaneously minimize BSFC and Brake Mean Effective Pressure (BMEP) under part load operation at a specified engine speed of 3000rpm. In particular, the decision parameters of the optimization process are the EIVC angle, the throttle valve opening and the waste-gate valve opening and combustion phasing. Proper constraints are assigned for the pressure in the intake plenum in order to limit the gas-dynamic noise radiated by the intake mouth.
The adopted optimization approach shows the capability to reproduce with a very good accuracy the experimentally advised optimal calibration, corresponding to the numerically derived Pareto frontier in the Brake Mean Effective Pressure (BMEP)-BSFC tradeoff. The optimization also underlines the advantages of an engine calibration based on a combination of EIVC strategy and intake throttling, rather than a purely throttle-based calibration.
The developed automatic procedure allows for a "virtual" calibration of the considered engine on completely theoretical basis and proves to be very helpful in reducing the experimental costs and the engine time-to-market.
References
Moriya Y, Watanabe A, Uda H, Kawamura H, Yoshioka M and Adachi M. A Newly Developed Intelligent Variable Valve Timing System – Continuously Controlled Cam Phasing as Applied to a New 3 Liter Inline 6 Engine. SAE Int Cong and Exp Detroit (USA) 1996. http://dx.doi.org/10.4271/960579
Maekawa K, Ohsawa N and Akasaka A. Development of a Valve Timing Control System. SAE Int Cong and Exp Detroit (USA) 1989.
Grohn M and Wolf K. Variable Valve Timing in the new Mercedes–Benz Four-Valve Engines. SAE Int Cong and Exp, Detroit (USA) 1989.
Fukuo K, Iwata T, Sakamoto Y, Imai Y, Nakahara K and Lantz K. A Honda 3.0 Liter, New V6 Engine. SAE Int Cong and Exp Detroit (USA) 1997.
Hatano K, Iida K, Higashi H and Murata S. Development of a New Multi-Mode Variable Valve Timing Engine. SAE Int. Cong and Exp, Detroit (USA) 1993.
Kreuter P, Heuser P and Schebitz M. Strategies to Improve SI-Engine Performance by Means of Variable Intake Lift, Timing and Duration. SAE Int Cong and Exp Detroit (USA) 1992.
Theobald MA, Lequesne B and Henry R. Control of Engine Load via Electromagnetic Valve Actuators. SAE Int Cong. and Exp, Detroit (USA) 1994. http://dx.doi.org/10.4271/940816
Tuttle J. Controlling Engine Load by Means of Late Intake- Valve Closing. SAE Technical paper 800794, 1980.
Urata Y, Umiyama H, Shimizu K, Fujiyoshi Y, Sono H and Fukuo K. A Study of Vehicle Equipped with Non-Throttling SI Engine with Early Intake Valve Closing Mechanism. SAE Int Cong and Exp Detroit (USA), 1993.
Lee JC, Lee CW and Nitkiewicz JA. The Application of a Lost Motion VVT System to a DOHC SI Engine. SAE Int Cong and Exp Detroit (USA), 1995.
Leone TG, Christenson EJ, Stein RA. Comparison of Variable Camshaft Timing Strategies at Part Load. SAE Int Cong and Exp Detroit (USA), 1996.
Haugen D, Blackshear P, Pipho M and Esler W. Modifications of a Quad 4 Engine to Permit Late Intake Valve Closure. SAE Int Off-Highway and Powerplant Cong and Exp, Milwaukee (USA) 1991.
Lancefield TM, Gayler RJ and Chattopadhay A. The Practical Application and Effects of a Variable Event Valve Timing System. SAE Int Congr and Exp Detroit (USA), 1993.
Vogel O, Roussopoulos K, Guzzella L and Czekaj J. Variable Valve Timing Implemented with a Secondary Valve on a Four Cylinder SI Engine. SAE Int Cong and Exp, Detroit (USA), 1997. http://dx.doi.org/10.4271/970335
Fontana G and Galloni E. Variable valve timing for fuel economy improvement in a small spark-ignition engine. Applied Energy 2009; 86 (1): 96-105. http://dx.doi.org/10.1016/j.apenergy.2008.04.009
Wirth M and Schulte H. Downsizing and Stratified Operation –an Attractive Combination Based on a Spray-guided Combustion System. Int Conf on Automotive Technologies, Istanbul, 2006.
Fraser N, Blaxill H, Lumsden G and Bassett M. Challenges for Increased Efficiency through Gasoline Engine Downsizing. SAE Int J of Engines 2009; 2(1): 991-1008. http://dx.doi.org/10.4271/2009-01-1053
Roepke K and Fischer M. Efficient Layout and Calibration of Variable Valve Trains. SAE World Congress, Detroit (USA), 2001.
Mohiuddin AKM, Ashour AAIS and Shin YH. Design optimization of valve timing at various engine speeds using Multi-Objective Genetic Algorithm (MOGA). Proc of 19th IASTED Int Conf on Modeling and Simulation, Quebec City (Canada) 2008.
Maiani F, Sisi A and Leardini W. Multi-Objective Optimization of the Timing System on a Small 2-Wheeler Engine (SOHC): Methodology and Case Study. SAE/JSAE Small Engine Technologies Conf. and Exhibition, Pisa 2014.
Franke C, Wirth A and Peters N. New Aspects of the Fractal Behavior of Turbulent Flames. XXIII Int Symp on Combustion, Orléans 1990.
Gatowsky J and Heywood J. Flame Photographs in a Spark- Ignition Engine. Combustion and Flame 1984; 56(1): 71-81. http://dx.doi.org/10.1016/0010-2180(84)90006-3
Gouldin F. An application of Fractals to Modeling Premixed Turbulent Flames. Combustion and Flame 1987; 68(3): 249- 266. http://dx.doi.org/10.1016/0010-2180(87)90003-4
De Bellis V, Severi E, Fontanesi S and Bozza F. Hierarchical 1D/3D approach for the development of a turbulent combustion model applied to a VVA turbocharged engine. Part II: Combustion model. Energy Procedia 2014; 45: 1027- 1036. http://dx.doi.org/10.1016/j.egypro.2014.01.108
De Bellis V, Severi E, Fontanesi S and Bozza F. Hierarchical 1D/3D approach for the development of a turbulent combustion model applied to a VVA turbocharged engine. Part I: Turbulence model. Energy Procedia 2014; 45: 829- 838. http://dx.doi.org/10.1016/j.egypro.2014.01.088
Cipolla G. Heat transfer correlations applicable to the analysis of internal combustion engine head cooling. Heat and Mass Transfer in Gasoline and Diesel Engines, New York: Hemisphere 1989; 373-396.
Teodosio L, De Bellis V and Bozza F. Fuel Economy Improvement and Knock Tendency Reduction of a Downsized Turbocharged Engine at Full Load Operations through a Low-Pressure EGR System. SAE Int J of Engines 2015; 8(4). http://dx.doi.org/10.4271/2015-01-1244
Bozza F, De Bellis V, Minarelli F and Cacciatore D. Knock and Cycle-by-Cycle Analysis of a High Performance V12 Spark Ignition Engine. Part 2: 1D Combustion and Knock Modeling. ICE2015 XII Int Conf on Engines and Vehicles, Capri (Italy), 2015.
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Copyright (c) 2015 Bozza Fabio, Teodosio Luigi