Effects of Different Injection Strategies on Combustion and Emission Characteristics of Diesel Engine Fueled with Dual Fuel

• Main Authors: Jianbin Luo, Zhonghang Liu, Jie Wang, Heyang Chen, Zhiqing Zhang, Boying Qin, Shuwan Cui
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Processes
• Subjects: diesel-natural gas; dual-fuel engine; diesel injection strategy; combustion; emission
• Online Access: https://www.mdpi.com/2227-9717/9/8/1300

In this work, an effective numerical simulation method was developed and used to analyze the effects of natural gas mixing ratio and pilot-main injection, main-post injection, and pilot-main-post injection strategies on the combustion and emission characteristics of diesel engine fueled with dual fuel. Firstly, the one-dimensional calculation model and three-dimensional CFD model of the engine were established by AVL-BOOST and AVL-Fire, respectively. In addition, the simplified chemical kinetics mechanism was adopted, which could accurately calculate the combustion and emission characteristics of the engine. The results show that the cylinder pressure and heat release rate decrease with the increase of the natural gas mixing ratio and the NO_x emission is reduced. When the NG mixing ratio is 50%, the NO_x and CO emission are reduced by 47% and 45%, respectively. When the SODI3 is 24 °CA ATDC, the NO_x emission is reduced by 29.6%. In addition, with suitable pilot-main injection and pilot-main-post injection strategies, the combustion in the cylinder can be improved and the trade-off relationship between NO_x and soot can be relaxed. Thus, the proper main-post injection strategy can improve the combustion and emission characteristics, especially the reduction in the NO_x and CO emissions.