Numerical simulation on combustion processes of a diesel engine under O₂/CO₂ atmosphere

Abstract

A new diesel engine combustion model where the fuel is sprayed into the combustion chamber and burnt under O₂/CO₂ atmosphere is presented. The new combustion model can break through the bondage of the compromise NO _x –soot emission curve which can make the engine meet the more stringent emission regulations. The numerical simulation model for diesel engine combustion analysis is built by AVL-FIRE software. The pressure, temperature and emissions field distribution in cylinder are calculated under O₂/CO₂ atmosphere and under normal air atmosphere, respectively, by maintaining the engine basic parameters unchanged. Simulation results show that when the O₂ ratio is under 50%, fuel cannot be ignited and the temperature variation in the cylinder is small. The content of 65% O₂ and 35% CO₂ is the optimal ratio under O₂/CO₂ atmosphere. Soot emission under O₂/CO₂ atmosphere is ultra-low, while CO emission is comparable to that under the normal air atmosphere.

Keywords:

• O₂/CO₂ atmosphere
• diesel engine
• combustion
• emission
• numerical simulation

Acknowledgements

Thanks are due to the Mechanical Engineering Postdoctoral Research Centre of Hefei University of Technology. This research was substantially supported by “the Natural Science Foundation of Anhui Province, China (Grant No.1308085QE79)”, “the Scientific Research Funds of Hefei University of Technology” (Project No. 2012HGXJ0669, 2011HGBZ0927), “the Open Funds of State Key Laboratory of Engines” (Project No. K2011-09) and “the National Natural Science Foundation of China” (Project No. NSFC 50776027, 50975073).