The impact of Miller cycle in combination to exhaust gas recirculation and post-injection on controlling diesel engine NO_x

ABSTRACT

To meet the requirements of increasing stringent emission regulations, innovative solutions are adopted to reduce NO_x emissions from diesel engines. In this study, the GT-Power software was utilized to investigate NO_x control possibility of Miller cycle in combination with exhaust gas recirculation (EGR) and post-injection in a diesel engine. The results indicate early intake valve closing reduced compression work, resulting in a power increase of 0.3 kW. Furthermore, the cooling effect of Miller cycle lowered maximum temperature by 24.5 K and NO_x emissions by 17.4%. Miller cycle and EGR combination was able to lower NO_x emissions by 83.7%, although it resulted in higher Soot emissions. Adding post-injection help to mitigate this issue, lowering NO_x emissions by over 20% and Soot emissions by 5.8%. Finally, the combination of MD75 + 12% EGR +2.5 mg post-injection mass at 34°CA ATDC achieved a 76.1% reduction in NO_x emissions with only a 2.6% impact on brake power using modeFRONTIER for multi-objective optimization.

KEYWORDS:

• Miller cycle
• EGR
• post-injection
• NO_x
• diesel engine

Acknowledgements

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability statement

The data that support the findings of this study are available from the corresponding author (https://cjxy.ujs.edu.cn/info/1063/4047.htm) upon reasonable request.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Jian Wang

Jian Wang received his Ph.D. in 2017. Now he is a professor of the School of Automotive and Traffic Engineering at Jiangsu University. His main research interests are internal combustion engine emission control, alternative fuels, and new vehicle technologies.

Luteng Chen

Jian Wang received his Ph.D. in 2017. Now he is a professor of the School of Automotive and Traffic Engineering at Jiangsu University. His main research interests are internal combustion engine emission control, alternative fuels, and new vehicle technologies.

Luteng Chen is currently a master student at Jiangsu University. His research interest is Miller cycle diesel engine.