Optimization research to minimize fuel consumption/ NOx emission of a two-stroke low speed marine diesel engine

This paper has proposed a single objective optimization approach using particle swarm optimization (PSO) algorithm to minimize fuel consumption (CO 2 emission) or NOx emissions. The proposed optimization approach is conducted based on a zero-dimensional engine model, which is validated with engine experiment data. The compression ratio (CR), start of injection timing (SOI) and exhaust valve closing timing (EC) are selected as optimization variables based on single-parameter sensitivity analysis, as they have significant impact on engine specific fuel oil consumption (SFOC) and NOx emissions. A diesel engine performance optimization program is established, with the minimum SFOC or NOx emissions as the optimization objective, respectively. During the optimization process, constraints on the maximum combustion pressure (P max ) and the maximum pressure rise rate are considered. A two-stroke diesel engine MAN’s 7G80ME-C is used for case analysis. The optimization results show that a maximum fuel reduction of 2.26% can be achieved at 100% load when SFOC is selected as objective. On the other hand, NOx emissions can be reduced up to 24.61% when minimizing NOx is selected as the objective.