EMISSION ANALYSIS OF A COMPRESSED NATURAL GAS DIRECTINJECTION ENGINE WITH A HOMOGENOUS MIXTURE

다국어 초록 (Multilingual Abstract)

In an era in which environmental pollution and depletion of world oil reserves are of major concern, emissions produced by automotive vehicles need to be controlled and reduced. An ideal solution is to switch to a cleaner fuel such as natural gas, which generates cleaner emissions. In addition, control over the in-cylinder air-fuel mixture can be best achieved through a direct-injection mechanism, which can further improve combustion efficiency. This need for cleaner automobiles provides the motivation for this paper’s examination of the use of computational fluid dynamic (CFD) simulations to analyze the concentrations of the exhaust gases produced by a compressed natural gas engine with a direct-fuel-injection system. In this work, a compressed natural gas direct-injection engine has been designed and developed through a numerical simulation using computational fluid dynamics (CFD) to provide an insight into complex in-cylinder behavior. The emissions analyzed in this study were carbon monoxide (CO), nitric oxide (NO) and carbon dioxide (CO2), i.e. the main pollutants produced by natural gas combustion. Based on a stoichiometric mixture, the concentrations of CO and NO were computed using the dissociation of carbon dioxide and the extended Zeldovich mechanism. CO2 was calculated using a mass balance of the species involved in the combustion process. The simulation results were then compared with the experimental data generated by a single-cylinder research engine test rig. A good agreement was obtained with the experimental data for the engine speeds considered for all emissions concentrations.

참고문헌 (Reference)

1 El-Tahry, S. H, "k-ε equation for compressible reciprocating engine flows" 7 (7): 345-353, 1983

2 Zellat, M, "Towards a universal combustion model in STAR-CD for IC engines: from GDI to HCCI and application to DI Diesel combustion optimization" 2005

3 Choa, H. M, "Spark ignition natural gas engines - A review" 48 (48): 608-618, 2007

4 Selamet, E. E., "Predicting chemical species in spark-ignition engines" 29 : 449-465, 2004

5 Magnussen, B. F, "On the structure of turbulence and a generalised eddy dissipation concept for chemical reaction in turbulent flow" 1981

6 Abdullah, S., "Numerical analysis of the combustion process in a com-pressed natural gas direct injection engine" 1 (1): 65-86, 2008

7 Belardini, P, "Multi-dimensional modelling of combustion and pollutants formation of new technology light duty diesel engines" 54 : 251-257, 1999

8 Agarwal, A, "Multi-dimensional modeling of ignition, combustion and nitric oxide formation in direct injection natural gas engines" SAE 2000

9 Launder, B. E, "Lectures in Mathematical Models of Turbulence" Academic Press Inc 1972

10 Soylu, S, "Examination of combustion characteristics and phasing strategies of a natural gas HCCI engine" 46 : 101-119, 2005

11 Huang, Z., "Effect of fuel injection timing relative to ignition timing on the natural gas direct-injection combustion" 125 : 783-790, 2003

12 Barths, H, "Computational fluid dynamics modelling of non-premixed combustion in direct injection diesel engines" 1 (1): 249-267, 2000

13 Zeng, K., "Combustion characteristics of a direct-injection natural gas engine under various fuel injection timings" 26 : 806-813, 2006

14 Borman, G. L, "Combustion Engineering" McGraw-Hill 1998

15 Wang, J., "Characteristics of direct injection combustion fuelled by natural gas–hydrogen mixtures using a constant volume vessel" 33 (33): 1947-1956, 2008

16 O. S. ABIANEH, "COMBUSTION DEVELOPMENT OF A BI-FUEL ENGINE" 한국자동차공학회 10 (10): 17-25, 2009

17 조행묵, "COMBUSTION AND EMISSION CHARACTERISTICS OF A LEAN BURN NATURAL GAS ENGINE" 한국자동차공학회 9 (9): 415-422, 2008

18 Turns, S. R, "An Introduction to Combustion - Concepts and Applications. 2nd Edn" McGraw-Hill 1999

19 Shiga, S, "A study of the combustion and emission characteristics of compressed-natural-gas direct-injection stratified combustion using a rapidcompression- machine" 129 : 1-10, 2002

20 Zhang, D. H, "A numerical study of natural gas combustion in a lean burn engine" 77 (77): 1339-1347, 1998

21 Zheng, Q. P, "A computational study of combustion in compression ignition natural gas engine with separated chamber" 84 : 1515-1523, 2005

22 Chen, R, "A computational study into the effect of exhaust gas recycling on homogeneous charge compression ignition combustion in internal combustion engines fuelled with methane" 41 : 805-813, 2002

23 Duclos, J. M., "3D modeling of combustion for DI-SI engines" 54 (54): 259-264, 1999