Development and application of a practical diesel-n-butanol-PAH mechanism in engine combustion and emissions prediction

ABSTRACT

A practical generation mechanism of n-butanol-polycyclic-aromatic-hydrocarbons (PAH) in diesel engine was established, and the generation kinetics of NOx and soot was embedded into the engine simulation. n-Dodecane, iso-cetane, iso-octane, toluene and decalin were used as a surrogate of diesel so as to achieve the purpose of physical and chemical properties of surrogate closer to the actual fuel. In order to further describe the soot behavior, the PAH model includes the formation pathways of A₁-A₇. The mechanism including 149 species and 497 reactions was first validated by zero-dimensional ignition delay, and the combustion properties of each constituent and diesel/n-butanol mixture were precisely captured by the mechanism. The combustion and emission characteristics of diesel/n-butanol blends were then studied using a computational fluid dynamics model coupled with the current mechanism in the engine operated under various exhaust gas recirculation and split injection strategies. Moreover, the findings also pinpoint that relative to 100% diesel, B30 exhibits decreasing emissions of NOx and soot at 25% EGR rate with the pilot/main injection timing of 342.5 °CA/360.5°CA and the pilot injection ratio of 8% or 10%.

KEYWORDS:

• Diesel-n-butanol-PAH mechanism
• EGR
• NOx
• soot
• split injection

Acknowledgments

“This work is supported by the National Natural Science Foundation of China (Grant No. 51806250 and 51976016). We also thank to the support by the Natural Science Foundation of Hunan Province, China (Grant No. 2019JJ50836)”.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51806250] and [51976016].

Notes on contributors

Yuqiang Li

Yuqiang Li, Associate Professor, School of Energy Science and Engineering, Central South University. The main research direction is Advanced Combustion and Emissions Control of Internal Combustion Engine.

Junhong Zhao

Junhong Zhao, School of Energy Science and Engineering, Central South University. The main research direction is Combustion Chemical Reaction Kinetics.

Wei Tang

Wei Tang, School of Energy Science and Engineering, Central South University. The main research direction is Multi-dimensional Combustion Simulation of Internal Combustion Engine.

Shitu Abubakar

Shitu Abubakar, College of Mechanical and Electrical Engineering, Central South University. The main research direction is New Energy vehicles.

Gang Wu

Gang Wu, Associate Professor, College of Automotive and Mechanical Engineering, Changsha University of Science and Technology. The main research directions are Vehicle Powertrain Combustion and Emission control.

Juan Huang

Juan Huang, College of Mechanical and Electrical Engineering, Hunan Agricultural University.  The main research direction is Internal Combustion Engine Emission Control Technology.