Mohammadreza NAZEMİ, Mahdi SHAHBAKHTİ, Hrishikesh SAİGAONKAR

Thermo-kinetic modelling of variable valve timing effects on Hcci Engine combustion

In this study the effects of variable valve timing on the combustion of a Homogeneous ChargeCompression Ignition (HCCI) engine have been analysed using a new modelling approach for HCCIengine cycle. A novel sequential modelling platform is developed using a combination of detailed multi -zone thermo- kinetic combustion model, 1D intake flow model and exhaust gas flow model. The newmodel utilizes CHEMKIN- PRO and GT - POWER software along with in- house exhaust gas flow model.Experimental data from a single-cylinder HCCI engine is used to validate the model. Validation resultsshow that the model can predict combustion phasing and Indicated Mean Effective Pressure (IMEP)with average errors of 1.1 crank angle degr ees (CAD) and 0.3 bar, respectively. The experimentallyvalidated model is then used to investigate the effects of intake valve timing on HCCI auto - ignitionradicals, zonal temperature, combustion phasing, IMEP, and exhaust emissions.

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1. H. Zhao, Homogeneous Charge Compression Ignition (HCCI) and Controlled Auto Ignition (CAI) Engines for the Automotive Industry, Woodhead Publishing, Brunel University, UK, 2007.
2. F. Zhao, T.W. Asmus, D.N. Assanis, J.E. Dec, J.A. Eng, and P.M. Najt, Homogeneous Charge Compression Ignition (HCCI) Engines: Key Research and Development, Progress In Technology, Issues PT - 94, 2003.
3. S. Saxena and I. D. Bedoya, Fundamental Phenomena Affecting Low Temperature Combustion and HCCI Engines, High Load Limits and Strategies for Extending These Limits, Progress in Energy and Combustion Science, 39(5): 457- 488, 2013.
4. N. Milovanovi c., R. Chen, and J.W.G. Turner. Influence of The Variable Valve Timing Strategy On The Control Of A Homogeneous Charge Compression (HCCI) Engine, SAE Technical Paper, 2004- 01 - 1899, 2004.
5. N. Milovanovic., D. Blundell, and J. Turner, Cam Profile Switching (CPS) And Phasing Strategy Vs Fully Variable Valve Train (FVVT) Strategy For Transitions Between Spark Ignition And Controlled Auto Ignition Modes, SAE Technical Paper, 2005- 01 - 0766, 2005.
6. S. M. Aceves, J. R. Smith., C. K. Westbrook, W. J. Compression Ratio Effect On Methane HCCI Combustion, Journal of Engineering for Gas Turbines and Power, 121(3): 569- 574, 1999.
7. D. Law, D. Kemp, J. Allen, G. Kirkpatrick, and T. Copland, Controlled Combustion in an IC- Engine With A Fully Variable Valve Train, SAE Technical Paper, 2001 - 01 - 0251, 2001.
8. P. A. Caton, H. H. Song, N. B. Kaahaaina, and C. F. Edwards. Residual- Effected Homogeneous Charge Compression Ignition With Delayed Intake- Valve Closing at Elevated Compression Ratio, International Journal of Engine Research, 6(4): 399- 419, 2005.
9. L. Koopmans, R. Ogink, and I. Denbratt., Direct Gasoline Injection in the Negative Valve Overlap of a Homogeneous Charge Compression Ignition Engine, SAE Transactions , pages 1365- 1376, 2003.
10. F.Agrell, H. Ångström , B Eriksson, J. Wikander, et al., Transient Control of HCCI Through Combined Intake and Exhaust Valve Actuation, SAE Technical Paper 2003 - 01 - 3172, 2003.
11. E. Hellström, A. G. Stefanopoulou, J. Vavra, A. Babajimopoulos, D. Assanis, L. Jiang and H. Yi lmaz, Understanding the dynamic evolution of cyclic variability at the operating limits of HCCI engines with negative valve overlap, SAE International Journal of Engines , 2012.
12. P. Borgqvist, P. Tunestål and B. Johansson, Investigation and comparison of residual gas enhanced HCCI using trapping (NVO HCCI) or rebreathing of residual gases, SAE Technical Paper 2011 - 01 - 1772, 2011.
13. P. Borgqvist, P. Tunestål, and B. Johansson, Comparison of negative valve overlap (NVO) and rebreathing valve strategies on a gasoline PPC engine at low load and idle operating conditions, SAE International Journal of Engines, 2013.
14. P. A. Caton, A. J. Simon, J. C. Gerdes, and C. F. Edwards Residual - effected homogeneous charge compression ignition at a low compression ratio using exhaust reinduction, International Journal of Engine Research, 2003.
15. H.Yun, N.Wermuth and P.Najt, High load HCCI operation using different valving strategies in a naturally- aspirated gasoline HCCI. SAE Technical Paper 2011 - 01 - 0899, 2011.
16. S. M. Aceves, D. L. Flowers, C. K. Westbrook, J. R Smith., W. Pitz, R. Dibble, M. Christensen and B. Johansson, A multi - zone model for prediction of HCCI combustion and emissions, SAE Technical Paper 2000- 01 - 0327, 2000.
17. M. Shahbakhti and C. R. Koch. Physics based control oriented model for HCCI combustion timing. ASME Journal of Dynamic Systems Measurement and Control, Vol. 132, Issue 2, 2010.
18. Aceves, S., Flowers, D., Martinez- Frias, J., Smith, J. et al., A Sequential Fluid- Mechanic Chemical - Kinetic Model of Propane HCCI Combustion, SAE Technical Paper 2001 - 01 - 1027, 2001.
19. M. Shahbakhti and C. R. Koch, Characterizing the cyclic variability of ignition timing in a homogeneous charge compression ignition engine fuelled with n- heptane/iso- octane blend fuels, International Journal of Engine Research, Vol. 9, Issue 5, pages 361 - 397, 2008.
20. N. P. Komninos, D. T. Hountalas and D. A. Kouremenos, Description of in- cylinder combustion processes in HCCI engines using a multi - zone model, SAE Technical Paper 2005- 05- 01 71, 2005.
21. H. Seiser, H. Pitsch, K. Seshadri, W. J. Pitz, and H. J. Curran, Extinction and autoignition of n- heptane in counterflow configuration Proceedings of the Combustion Institute, 28(2): 2029- 2037, 2000.
22. G. Woschni, Universally applicable equation for the instantaneous heat transfer coefficient in the internal combustion engine SAE Technical Paper 670931, 1967.
23. P. Kirchen, M. Shahbakhti and C. R. Koch, A skeletal kinetic mechanism for PRF combustion in HCCI engines, Journal of Combustion Science and Technology, 179(6): 1059 - 1083, 2007.