Research on performance matching of intake and exhaust ports of marine medium speed dual fuel engine

The performance influence on the dual fuel engine by the intake/exhaust port flow coefficient and swirl are major factors to the dual fuel engine. Therefor the optimization of the intake and the exhaust ports was carried out to ensure the adaptability of the airway structure to the ACD320 dual fuel engine in this paper. According to the limitation conditions of the structural parameters, the multiple airways crossing the diameter of the intake/exhaust port were designed. The research on variation rules of flow and swirl characteristics in different intake/exhaust port circulation cross-sectional area by aerodynamics modeling and simulating approach to optimizing the matching degree between the cylinder and the intake/exhaust port of a marine dual fuel engine was presented. And the optimizing match results were verified and analyzed by the experimental results of the practical intake and exhaust port models. The influence on the performance by the intake/exhaust air flow area and the valve lift is analyzed comprehensively by the AVL test results of the intake and the exhaust ports. The suction and combustion processes at different size of intake and exhaust port are simulated by AVL Fire to validate the optimum matching. Results show that the intake flow coefficient tends to be stable when the diameter of the intake port greater than 83 mm, the swirl number tends to be stable when the diameter of the intake port greater than 88 mm and the exhaust flow coefficient tends to be stable when the diameter of the exhaust port greater than 80 mm. Analysis show that the mean flow coefficient present optimum consequence when the diameter of the intake port is 88.6 mm. By analyzing and comparing intake airflow, efficiency, emissions and indicate power, the fifth group (intake port 88.60 mm, exhaust port 80.00 mm) matching is the optimum matching for ACD320 type marine dual fuel engine. The results provide reference for the design and optimization of dual fuel engine. (C) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).