Collaborative optimization of exhaust gas recirculation and Miller cycle of two-stage turbocharged marine diesel engines based on particle swarm optimization

• Published in: Journal of Central South University 2022-07, Vol.29 (7), p.2142-2156
• Main Authors: Tang, Xu-yang, Wang, Peng, Zhang, Zhong-yuan, Zhang, Feng-li, Shi, Lei, Deng, Kang-yao
• Format: Article
• Language: English
• Subjects: Algorithms; Collaboration; Diesel engines; Emission standards; Engineering; Exhaust gases; Exhaust systems; Full load; Marine engines; Metallic Materials; Multiple objective analysis; Nitrogen oxides; Numerical models; Optimization; Particle swarm optimization; Superchargers; The 2nd World Congress on Internal Combustion Engines; Turbines
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-022-5082-x

To meet increasingly stringent emission standards and lower the brake-specific fuel consumption (BSFC) of marine engines, a collaborative optimization study of exhaust gas recirculation (EGR) and a Miller cycle coupled turbocharging system was carried out. In this study, a one-dimensional numerical model of the EGR, Miller cycle, and adjustable two-stage turbocharged engine based on WeiChai 6170 marine diesel engine was established. The particle swarm optimization algorithm was used to achieve multi-input and multi-objective comprehensive optimization, and the effects of EGR-coupled Miller regulation and high-pressure turbine bypass regulation on NO x and BSFC were investigated. The results showed that a medium EGR rate-coupled medium Miller degree was better for the comprehensive optimization of NO x and BSFC. At medium EGR rate and low turbine bypass rates, NO x and BSFC were relatively balanced and acceptable. Finally, an optimal steady-state control strategy under full loads was proposed. With an increase in loads, the optimized turbine bypass rate and Miller degree gradually increased. Compared with the EGR-only system, the optimal system of EGR and Miller cycle coupled turbine bypass reduced NO x by 0.87 g/(kW·h) and BSFC by 17.19 g/(kW·h) at 100% load. Therefore, the EGR and Miller cycle coupled adjustable two-stage turbocharging achieves NO x and BSFC optimization under full loads.