Control of peak pressures of an HCCI engine under varying swirl and operating parameters

Abstract

The major advantages of homogeneous charge compression ignition (HCCI) are high efficiency in combination with low NO_x-emissions. However, one of the major challenges with HCCI is the control of higher peak pressures which may damage the engine, limiting the HCCI engine life period. In this paper, an attempt is made to analyze computationally the effect of induction swirl in controlling the peak pressures of an HCCI engine under various operating parameters. A single cylinder 1.6 L reentrant piston bowl diesel engine is chosen. For computational analysis, the ECFM-3Z model of STAR –CD is considered because it is suitable for analyzing the combustion processes in SI and CI engines. As an HCCI engine is a hybrid version of SI and CI engines, the ECFM-3Z model with necessary modifications is used to analyze the peak pressures inside the combustion chamber. The ECFM-3Z model for HCCI mode of combustion is validated with the existing literature to make sure that the results obtained are accurate. Numerical experiments are performed to study the effect of varying properties like speed of the engine, piston bowl geometry, exhaust gas recirculation (EGR) and equivalence ratio under different swirl ratios in controlling the peak pressures inside the combustion chamber. The results show that the swirl ratio has a considerable impact on controlling the peak pressures of HCCI engine. A reduction in peak pressures are observed with a swirl ratio of 4 because of reduced in cylinder temperatures. The combined effect of four operating parameters, i.e., the speed of the engine, piston bowl geometry, EGR, and equivalence ratio with swirl ratios suggest that lower intake temperatures, reentrant piston bowl, higher engine speeds and higher swirl ratios are favorable in controlling the peak pressures.

Key words： HCCI engine; ECFM-3Z; Swirl ratio; peak pressures; engine speed; piston bowl geometry

References

1 Karthikeya Sharma T, Amba Prasad Rao G, Madhu Murthy K. Performance of HCCI diesel engine under the influence of various working and geometrical parameters. International Journal on Theoretical and Applied Research in Mechanical Engineering, 2012, 1(1): 2319–3182

2 Epping K, Aceves S, Bechtold R, Dec J E. The potential of HCCI combustion for high efficiency and low emissions. SAE Technical Paper, 2002, Paper No. 2002-01-1923

3 Liu B, Su W, Wang H, Huang H. Characteristics and energy distribution of modulated multi-pulse injection modes based diesel HCCI combustion and their effects on engine thermal efficiency and emissions. Frontiers of Energy and Power Engineering in China, 2007, 1(4): 420–427

4 Heywood J B. Internal Combustion Engine Fundamentals. New York: McGraw-Hill, Inc., 1988

5 Onishi S, Jo S H, Shoda K, Jo P D, Kato S. Active thermo-atmosphere combustion (ATAC)—a new combustion process for internal combustion engines. SAE Paper, 1979, Paper No. 790501

6 Karthikeya Sharma T, Amba Prasad Rao G, Madhu Murthy K. Combustion analysis of ethanol in an HCCI engine. Trends in Mechanical Engineering and Technology, 2013, 3(2): 6

7 Manimaran R, Thundil Karuppa Raj R. Computational studies of swirl ratio and injection timing on atomization in a direct injection diesel engine. Frontiers in Heat and Mass Transfer, 2014, 5(1): 7

8 Venkateswaran S P, Nagarajan G. Effects of the re-entrant bowl geometry on a DI turbocharged diesel engine performance and emissions—a CFD approach. Journal of Engineering for Gas Turbines and Power, 2010, 132(12): 122803

9 Maroteaux F, Noel L, Ahmed A. Numerical investigations on methods to control the rate of heat release of HCCI combustion using reduced mechanism of n-heptane with a multidimensional CFD code. Combustion Theory and Modelling, 2007, 11(4): 501–525

10 Duclos J P, Zolver M, Baritaud T. 3D modeling of combustion for DI-SI engines. Oil & Gas Science and Technology, 1999, 54(2): 259–264

11 Colin O, Benkenida A. The 3-zone extended coherent flame model (ECFM3Z) for computing premixed/diffusion combustion. Oil & Gas Science and Technology – Rev. IFP, 2004, 59(6): 593–609

12 Abouri D, Zellat M, Duranti S, Ravet F. Advances in combustion modeling in STAR-CD: validation of ECFM CLE-H model to engine analysis. In: 18th International Mutidimentional Engine User’s Meeting at the SAE Congress. Detroit, USA, 2008

13 Subramanian G, Vervisch L, Ravet F. New developments in turbulent combustion modeling for engine design: ECFM-CLEH combustion sub-model. SAE Technical Paper, 2007, Paper No. 2007-01-0154

14 Moureau V, Lartigue G, Sommerer Y, Angelberger C, Colin O, Poinsot T. Numerical methods for unsteady compressible multi-component reacting flows on fixed and moving grids. Journal of Computational Physics, 2005, 202(2): 710–736

15 Zellat M, Duranti S, Liang Y, Kralj C, Schmidt G, Duclos J M. Towards a universal combustion model in STAR-CD for IC engines: from GDI to HCCI and application to DI Diesel combustion optimization. In: Proceedings of 14th SAE International Multidimensional Engine User’s Meeting. Detroit, USA, 2005

16 Bakhshan Y, Tarahomi A R. Multi-dimensional simulation of n-heptane combustion under HCCI engine condition using detailed chemical kinetics. Journal of Engine Research, 2011, 22: 3–12

17 Ganesh D, Nagarajan G. Homogeneous charge compression ignition (HCCI) combustion of diesel fuel with external mixture formation. Energy, 2010, 35(1): 148–157

18 Viggiano A, Magi V. A comprehensive investigation on the emissions of ethanol HCCI engines. Applied Energy, 2012, 93: 277–287

19 Sjöberg M, Dec J E. Effects of engine speed, fueling rate, and combustion phasing on the thermal stratification required to limit HCCI knocking intensity. SAE Technical Paper, 2005, Paper No. 2005-01-2125

20 Gu Y, Mayor J R, Dahm W J A. Turbulence-augmented minimization of combustion time in mesoscale internal combustion engines. In: 44th AIAA Aerospace Sciences Meeting and Exhibit. Reno, USA, 2006, AIAA-2006-1350

21 Chen G, Iida N, Huang Z. Numerical study of EGR effects on reducing the pressure rise rate of HCCI engine combustion. Frontiers of Energy and Power Engineering in China, 2010, 4(3): 376–385

22 Murali K B, Mallikarjuna J M. Effect of engine speed on peak tumble flows in a motored internal combustion engine-an experimental investigation using particle image velocimetry. Journal of Applied Fluid Mechanics, 2011, 4(1): 1–14

23 Martinez-Frias J, Aceves S M, Flowers D, Smith J R, Dibble R. Equivalence ratio-EGR control of HCCI engine operation and the potential for transition to spark-ignited operation. SAE Technical Paper, 2001, Paper No. 2001-01-3613

24 Christensen M, Johansson B. Influence of mixture quality on homogeneous charge compression ignition. SAE Transactions. Journal of Fuels and Lubricants, 1998, 107: 1–13

25 Jaichandar S, Annamalai K. Influences of re-entrant combustion chamber geometry on the performance of Pongamia biodiesel in a DI diesel engine. Energy, 2012, 44(1): 633–640