A Numerical Study on Combustion and Emission Characteristics of a Medium-Speed Diesel Engine Using In-Cylinder Cleaning Technologies

Energies

Shuang He²  Bao-Guo Du²  Li-Yan Feng²  Yao Fu²  Jing-Chen Cui²  Wu-Qiang Long¹ 

[1] Institute of Internal Combustion Engine, Dalian University of Technology, Dalian 116024, China;

关键词: medium-speed diesel engine;    Miller cycle;    EGR;    NO_x emissions;    numerical simulation;   

DOI  :  10.3390/en8054118

来源: mdpi

【 摘 要 】

In order to clarify the potential of internal purification methods on medium speed diesel engines to meet the IMO Tier III nitrogen oxide (NO_x) emission regulations, combined 1-D engine working cycle simulation and 3-D CFD simulation were conducted to predict the performance and emissions of the engine under different valve close timings, geometric compression ratios, injection timings, and Exhaust Gas Recirculation (EGR) rates. The numerical results show that, as the inlet valve close timing is advanced, NO_x is reduced by as much as 27%, but the peak of premixed combustion heat release rate is increased; this can weaken the ability to reduce NO_x with the Miller cycle. Moreover, the peak of premixed combustion heat release rate is reduced when the geometric compression ratio is increased to 15.4, and linking with injection timing by delaying 6°CA can further reduce NO_x by 55.3% from the baseline. Finally, over 80% NO_x reduction can be achieved when the above schemes are combined with over 15% EGR. The NO_x and soot can be reduced simultaneously by using moderate Miller cycle combination with moderate EGR, and the results show a large reduction of NO_x and moderate reduction of soot. This can be a feasible technical solution to meet Tier III regulations.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.